Integrating Bio-Oils and Pyrolysis Liquids: A Strategic Pathway for Co-processing Biomass Intermediates in Petroleum Refineries

Abstract

This article provides a comprehensive analysis for researchers and process engineers on the co-processing of biomass-derived intermediates (e.g., fast pyrolysis oil, hydrothermal liquefaction biocrude) within existing petroleum refinery infrastructure. It explores the foundational science behind biomass intermediate properties and refinery compatibility, details current methodologies for hydrotreating and catalytic cracking integration, addresses critical challenges in catalyst deactivation and process stability, and validates performance through comparative techno-economic and life-cycle assessments. The synthesis offers a roadmap for leveraging refinery assets to produce sustainable, drop-in hydrocarbon fuels and chemicals.

Understanding Biomass Intermediates: Chemistry, Properties, and Refinery Integration Potential

Within the context of co-processing biomass intermediates in petroleum refineries, defining the key intermediates—pyrolysis oil, biocrude, and sugars—is critical. These intermediates serve as bridge molecules, derived from diverse biomass feedstocks, and are designed for integration into existing refinery infrastructure (e.g., fluid catalytic cracking (FCC) units, hydrotreaters). This application note details their definitions, properties, and provides standardized protocols for their analysis and upgrading, targeting researchers and scientists engaged in renewable fuel and chemical development.

Definitions and Key Characteristics

Pyrolysis Oil (Bio-oil): A dark brown, acidic liquid produced from the fast pyrolysis of lignocellulosic biomass (e.g., wood, agricultural residues) at moderate temperatures (≈500°C) in the absence of oxygen. It is a complex, unstable emulsion containing water, hundreds of oxygenated organic compounds (acids, aldehydes, phenolics), and solid char particles.

Biocrude (Hydrothermal Liquefaction (HTL) Oil): A viscous, tar-like substance produced via hydrothermal liquefaction of wet biomass (e.g., algae, sewage sludge, food waste) at high pressure (50-200 bar) and temperature (250-400°C) in a water medium. It has lower oxygen content than pyrolysis oil but is rich in nitrogen (when from proteinaceous feedstocks) and has higher molecular weight compounds.

Sugars (Fermentable Sugars): Primarily monomeric C5 and C6 sugars (e.g., glucose, xylose) obtained from the saccharification of carbohydrate fractions (cellulose, hemicellulose) in biomass through biochemical (enzymatic) or thermochemical pretreatment and hydrolysis pathways. They are water-soluble, reactive intermediates for biological upgrading.

Quantitative Comparison of Key Properties

Table 1: Representative Properties of Biomass Intermediates for Co-processing Assessment

Property	Pyrolysis Oil	Biocrude (from algae)	Sugars (Glucose Solution)
Carbon Content (wt%)	50-65	70-80	40 (in solution)
Oxygen Content (wt%)	35-50	10-20	~53 (anhydrous basis)
Hydrogen Content (wt%)	5-7	8-12	~7 (anhydrous basis)
Water Content (wt%)	15-35	5-10	Variable (aqueous solution)
HHV (MJ/kg)	16-19	30-38	~15.6 (anhydrous)
Viscosity (cP, 40°C)	25-1000 (ages rapidly)	1000-15000	~1 (aqueous solution)
pH	2.0-3.5	5.0-7.0	~7 (neutral)
Primary Upgrading Route for Co-processing	Catalytic Hydrodeoxygenation (HDO)	Hydrotreating/Hydrocracking	Catalytic Aqueous Phase Reforming (APR) or Fermentation

Experimental Protocols

Protocol 4.1: Analytical Characterization of Pyrolysis Oil for Co-processing Feedstock Suitability

Objective: To determine key properties of pyrolysis oil that impact its compatibility with refinery hydroprocessing units. Materials: Pyrolysis oil sample, Karl Fischer titrator, bomb calorimeter, viscometer, GC-MS, ICP-OES. Procedure:

• Water Content: Use volumetric Karl Fischer titration according to ASTM E203.
• Heating Value: Determine Higher Heating Value (HHV) using an isoperibol bomb calorimeter (ASTM D240).
• Viscosity: Measure kinematic viscosity at 40°C using a calibrated glass capillary viscometer (ASTM D445).
• Chemical Composition: Dilute 100 mg of oil in 1 mL methanol, filter (0.2 µm PTFE). Analyze by GC-MS with a DB-1701 column (60m, 0.25mm ID). Oven program: 40°C (hold 5 min) to 280°C at 4°C/min.
• Ash & Metal Content: Digest 5g sample in nitric acid and analyze via ICP-OES (ASTM D5185) for Na, K, Ca, Mg.

Protocol 4.2: Hydrodeoxygenation (HDO) Screening of Pyrolysis Oil/Biocrude

Objective: To assess the catalytic upgrading of intermediates via HDO to reduce oxygen content. Materials: 100 mL batch reactor (Parr), catalyst (e.g., sulfided CoMo/Al₂O₃), decalin solvent, high-pressure H₂. Procedure:

• Charge reactor with 10g intermediate, 40g decalin, and 1g catalyst.
• Purge reactor 3x with 20 bar N₂, then pressurize with H₂ to 50 bar at room temperature.
• Heat to 350°C with vigorous stirring (750 rpm) and maintain for 4 hours.
• Cool reactor to <50°C, release gas, and collect liquid product.
• Separate oil product from aqueous phase. Analyze oil for O-content via elemental analysis and GC-MS for deoxygenation products.

Protocol 4.3: Catalytic Co-processing of Biocrude with Vacuum Gas Oil (VGO) in a Microactivity Test (MAT) Unit

Objective: To evaluate the performance of biocrude blended with VGO in a simulated FCC process. Materials: MAT unit, VGO, biocrude, equilibrium FCC catalyst (E-cat), gas chromatograph. Procedure:

• Prepare a 10:90 wt/wt blend of biocrude and VGO (homogenize at 60°C).
• Load 4g of E-cat into the MAT fixed-bed reactor.
• Inject 1.2g of the feed blend into the catalyst bed at 520°C using a syringe pump.
• Vapors are carried by N₂, condensed, and collected. Non-condensable gases are collected in a gas burette.
• Analyze liquid products via simulated distillation (ASTM D2887) and gas composition via GC-TCD. Calculate yields of gasoline, LCO, and coke.

Protocol 4.4: Catalytic Aqueous Phase Reforming (APR) of Sugar Solutions

Objective: To convert aqueous sugar streams to alkanes or hydrogen suitable for refinery integration. Materials: 300 mL Parr reactor, Pt/Al₂O₃ catalyst, 10 wt% glucose solution, HPLC. Procedure:

• Charge reactor with 150g of 10 wt% glucose solution and 1.5g Pt/Al₂O₃ catalyst.
• Purge with 10 bar N₂, then pressurize to 30 bar with N₂.
• Heat to 225°C with stirring (1200 rpm) and maintain for 4 hours.
• Cool, collect gas (analyze for H₂, CO₂, alkanes via GC), and filter liquid product.
• Analyze liquid for remaining sugars and polyols via HPLC-RI (Aminex HPX-87H column, 0.6 mL/min 5mM H₂SO₄).

Visualizations

Diagram 1: Biomass to Intermediates to Refinery Pathways

Diagram 2: Pyrolysis Oil Feedstock Suitability Workflow

The Scientist's Toolkit: Key Research Reagents & Materials

Table 2: Essential Materials for Biomass Intermediate Co-processing Research

Item	Function / Role in Research	Example Specification / Note
Sulfided CoMo/Al₂O₃ Catalyst	Benchmark hydrotreating catalyst for hydrodeoxygenation (HDO) of pyrolysis oil/biocrude.	Typically 3-5% CoO, 10-15% MoO₃; requires pre-sulfidation.
Equilibrium FCC Catalyst (E-cat)	Realistic, deactivated catalyst for co-processing experiments simulating industrial FCC conditions.	Collected from commercial FCC units; contains metals (Ni, V).
Pt/Al₂O₃ or Pt-Re/C Catalyst	Catalysts for aqueous phase reforming (APR) of sugar solutions to alkanes/hydrogen.	3-5 wt% Pt loadings; high surface area support (>150 m²/g).
Decalin (Decahydronaphthalene)	High-boiling, hydrogen-donor solvent used in batch HDO experiments to improve oil yield and mixing.	Technical grade, mixture of cis and trans isomers.
Model Compound Mixtures	Simplifies complex intermediate analysis (e.g., guaiacol for pyrolysis oil, stearic acid for biocrude).	Analytical standard purity (>98%) for calibration.
Microactivity Test (MAT) Unit	Bench-scale fixed-bed reactor for standardized FCC catalyst performance evaluation.	ASTM D5154 compliant; measures activity, selectivity.
Anhydrous Glucose Standard	Primary standard for calibrating sugar analysis methods (HPLC, GC) in aqueous streams.	ACS reagent grade, for preparing precise calibration curves.

Application Notes

Thesis Context: Co-processing Biomass Intermediates in Petroleum Refineries

The integration of biomass-derived intermediates (e.g., pyrolysis oil, hydrotreated vegetable oil) into conventional petroleum refinery units (e.g., fluid catalytic cracker, hydrocracker) is a promising route for renewable fuel production. The success of this co-processing is critically governed by the key chemical characteristics of the bio-intermediates relative to petroleum streams. Oxygen content dictates hydrotreating severity and catalyst lifetime. Acidity (TAN) causes corrosion in refinery infrastructure. Thermal and storage stability impact handling and pre-processing. Heating value directly affects the energy density of the final fuel blend. Optimizing or mitigating these properties is central to research in this field.

Table 1: Characteristic Ranges for Petroleum and Biomass Intermediates

Characteristic	Typical Petroleum Feedstock	Fast Pyrolysis Bio-Oil	Hydrotreated Vegetable Oil (HVO)	Upgraded Bio-Oil (Deoxygenated)
Oxygen Content (wt%)	<0.5	35-50	<1	5-15
Total Acid Number (TAN) (mg KOH/g)	<0.1	50-150	<0.5	1-10
Heating Value (MJ/kg)	42-45	15-20	43-46	35-40
Water Content (wt%)	<0.5	15-30	<0.1	1-5
Storage Stability	Stable	Poor (Ages rapidly)	Excellent	Moderate

Table 2: Impact of Key Characteristics on Refinery Co-processing

Characteristic	Primary Impact on Co-processing	Typical Mitigation Strategy
High Oxygen Content	Excessive H2 consumption, catalyst coking/deactivation, immiscibility	Catalytic hydrodeoxygenation (HDO) prior to blending
High Acidity (High TAN)	Corrosion of pipelines, tanks, and unit components	Neutralization, blending with low-TAN feed, use of corrosion-resistant materials
Low Heating Value	Lower energy output of final fuel product, process inefficiency	Blending at low ratios (<10%), complete deoxygenation
Poor Thermal Stability	Polymerization and coke formation in pre-heaters and reactors	Mild hydrotreating (stabilization), low-temperature storage, addition of stabilizers

Experimental Protocols

Protocol 1: Determination of Oxygen Content by Elemental Analysis

Objective: Quantify the weight percentage of oxygen in a biomass intermediate. Principle: Modern elemental analyzers use combustion analysis (for C, H, N, S) and calculate oxygen by difference: O (wt%) = 100% - (C% + H% + N% + S% + Ash%). Procedure:

• Calibration: Calibrate the elemental analyzer (e.g., CHNS/O analyzer) using certified standards like acetanilide.
• Sample Prep: Homogenize the liquid bio-oil sample. For solid biomass, grind and dry. Weigh 2-5 mg of sample into a clean tin capsule. Seal capsule tightly.
• Combustion: Load the capsule into the auto-sampler. The sample is combusted at ~1000°C in a pure oxygen environment.
• Detection: Resultant gases (CO2, H2O, N2, SO2) are separated and quantified by thermal conductivity or infrared detectors.
• Calculation: The instrument software reports C, H, N, S percentages. Ash content is determined separately via thermogravimetric analysis. Oxygen is calculated by difference. Note: For direct O measurement, use a pyrolysis reactor coupled to a detector.

Protocol 2: Measurement of Total Acid Number (TAN)

Objective: Determine the acidity of a bio-oil sample per ASTM D664. Principle: Potentiometric titration of acidic constituents with standardized KOH. Procedure:

• Reagent Prep: Prepare a 0.1 M KOH in isopropanol solution, standardize with potassium hydrogen phthalate.
• Sample Prep: Weigh 2-10 g of bio-oil into a titration beaker. Add 50 mL of titration solvent (toluene + isopropanol + water).
• Titration: Immerse the pH electrode and stir. Titrate with 0.1 M KOH using an automatic titrator. Record the volume of titrant added versus pH.
• Endpoint Determination: The endpoint is identified by the software as the point of maximum inflection in the pH curve (typically corresponding to pH ~11).
• Calculation: TAN (mg KOH/g) = (A * M * 56.1) / W, where A = titrant volume (mL), M = molarity of KOH, W = sample weight (g).

Protocol 3: Accelerated Stability Test

Objective: Assess the thermal and storage stability of bio-oil by monitoring viscosity change. Principle: Aging is accelerated by elevated temperature. Increased viscosity indicates polymerization. Procedure:

• Baseline Measurement: Measure the initial kinematic viscosity of the bio-oil at 40°C using a calibrated viscometer (ASTM D445).
• Aging: Aliquot 50 mL of bio-oil into a sealed glass vial under nitrogen. Place the vial in an oven at 80°C for 24 hours.
• Post-Aging Analysis: Cool the sample to room temperature. Measure the final kinematic viscosity at 40°C.
• Calculation: Calculate the viscosity increase rate: % Increase = [(Vfinal - Vinitial) / V_initial] * 100. A >50% increase indicates poor stability.

Protocol 4: Determination of Higher Heating Value (HHV)

Objective: Measure the gross heat of combustion using a bomb calorimeter (ASTM D240). Principle: Complete combustion of a sample in high-pressure oxygen, with measurement of the temperature rise in a calibrated water jacket. Procedure:

• Calibration: Calibrate the bomb calorimeter using certified benzoic acid.
• Pellet Prep: For liquid samples, use a polyester bag or gelatin capsule. Weigh ~0.5-1.0 g sample.
• Combustion: Assemble the bomb with the sample pellet, 10 cm of fuse wire, and fill with pure oxygen to 30 atm. Submerge the bomb in a known mass of water in the calorimeter jacket.
• Ignition & Measurement: Initiate combustion electrically. Record the precise temperature change of the water jacket.
• Calculation: The calorimeter software calculates HHV (MJ/kg) based on the temperature rise, accounting for heat from fuse wire and any acid corrections.

Diagrams

Bio-Oil Co-processing Workflow

High O & Acidity Refinery Impacts

The Scientist's Toolkit: Key Research Reagent Solutions

Table 3: Essential Materials for Biomass Intermediate Analysis

Item	Function/Application	Key Notes
Anhydrous Toluene & Isopropanol	Solvent for TAN titration (ASTM D664).	Must be of high purity to avoid interference; forms the titration medium.
Standardized KOH in IPA (0.1M)	Titrant for acidity measurement.	Requires frequent re-standardization; hygroscopic.
Benzoic Acid Calorific Standard	Primary standard for bomb calorimeter calibration.	Certified with known HHV; ensures measurement accuracy.
Acetanilide / Sulfanilamide	CHNS elemental analysis calibration standard.	Provides certified C, H, N, S percentages for instrument calibration.
Nitrogen (High Purity)	Inert atmosphere for sample storage and aging tests.	Prevents oxidative degradation of sensitive bio-oils during handling.
Stabilizer Additives (e.g., methanol, aldehydes scavengers)	Experimental agents to improve bio-oil stability.	Used in stability protocol studies to assess viscosity reduction.
Deoxygenation Catalyst (e.g., CoMo/Al2O3, NiMo/Al2O3, Pt/SiO2-Al2O3)	Hydrotreating catalyst for model compound or bio-oil HDO studies.	Bench-scale reactors (e.g., trickle bed) to study O-removal efficiency.
Corrosion Coupons (Carbon steel, 304/316 SS)	Materials testing for bio-oil corrosivity.	Immersed in bio-oil at elevated T; weight loss measures corrosion rate.

Application Notes

Co-processing biomass intermediates in petroleum refineries presents a pivotal pathway for low-carbon fuel production. The strategic rationale centers on leveraging mature, high-capacity refinery units—chiefly the Fluid Catalytic Cracker (FCC) and hydrotreaters—to upgrade bio-intermediates (e.g., pyrolysis oil, hydrotreated vegetable oil) alongside conventional petroleum streams. This approach minimizes capital expenditure, accelerates deployment, and utilizes existing scale and logistical networks.

1.1 Key Infrastructure Utilization

• FCC Unit: Primarily designed for vacuum gasoil (VGO) conversion, the FCC can co-process deoxygenated biomass feeds (like catalytic pyrolysis oil) to produce olefins, gasoline, and LCO. The zeolite catalyst's acid sites catalyze cracking, isomerization, and deoxygenation reactions.
• Hydrotreaters (HTU): Essential for oxygen removal, hydrotreaters (using CoMo/NiMo catalysts) stabilize reactive bio-oils via hydrodeoxygenation (HDO), hydrodesulfurization (HDS), and saturation reactions, making them compatible with downstream FCC or direct blending.

1.2 Quantitative Data Summary

Table 1: Performance Data for Co-processing in FCC Units

Feedstock Blend (Biomass:VGO)	Co-processing Ratio (wt%)	Oxygen Content in Feed (wt%)	Main Liquid Product Yield (wt%)	Deoxygenation Efficiency (%)	Key Challenges
Catalytic Pyrolysis Oil (CPO)	5:95	2.1	78.5	~85	Catalyst coking, increased gas yield
Hydrotreated Pyrolysis Oil (HPO)	10:90	0.8	75.2	>95	Hydrogen consumption, catalyst deactivation
Hydroprocessed Esters & Fatty Acids (HEFA)	20:80	~0.1	81.0	~99	Feedstock cost, hydrogen availability

Table 2: Hydrotreater Performance for Bio-Intermediate Stabilization

Bio-Intermediate Feed	Catalyst System	Typical Operating Conditions	Product Oxygen (wt%)	Key Function
Raw Pyrolysis Oil	CoMo/Al₂O₃	300-400°C, 80-140 bar	< 5.0	Bulk HDO, stabilization
HEFA/Vegetable Oil	NiMo/Al₂O₃	300-380°C, 50-80 bar	< 0.5	Full deoxygenation to paraffins
Co-processed VGO/Bio-Oil	Guard Bed + NiMo	340-380°C, 100-120 bar	< 1.0	HDO, HDS, metals removal

Experimental Protocols

2.1 Protocol A: Catalytic Co-processing in a Microactivity Test (MAT) Unit (Simulating FCC) Objective: Evaluate the cracking performance and product distribution of VGO blended with hydrotreated bio-oil. Materials: Microactivity Test (MAT) reactor, VGO feedstock, hydrotreated pyrolysis oil (HPO), equilibrated FCC catalyst (E-Cat), gas collection system, GC-MS/FID for analysis. Procedure:

• Feed Preparation: Pre-blend HPO with VGO at desired ratios (e.g., 5/95, 10/90 w/w). Homogenize via stirring at 60°C for 1 hour.
• Reactor Loading: Load 4.0 g of E-Cat into the fixed-bed MAT reactor. Condition the catalyst under nitrogen flow (30 mL/min) at 500°C for 1 hour.
• Reaction: Reduce temperature to the target reaction temperature (typically 525-550°C). Inject 1.33 g of the blended feed via syringe pump over 75 seconds. Use an internal standard (e.g., dimethyl disulfide) for quantitative analysis.
• Product Collection: Collect liquid products in a chilled receiver, non-condensable gases in a gas burette or bag.
• Analysis: Weigh liquid and coke (via catalyst burn-off). Analyze gas composition by GC-TCD and liquid composition by Simulated Distillation (SIMDIS) and GC-MS.
• Calculations: Determine conversion, yields (dry gas, LPG, gasoline, LCO, HCO, coke), and product selectivity.

2.2 Protocol B: Stabilization & Deoxygenation of Bio-Oil in a Trickle-Bed Hydrotreater Objective: Assess the hydrodeoxygenation (HDO) efficiency of raw pyrolysis oil using a commercial hydrotreating catalyst. Materials: High-pressure trickle-bed reactor (ID: 10-12 mm), CoMo/Al₂O₃ catalyst (sized to 0.3-0.6 mm), raw pyrolysis oil, high-purity H₂, HPLC pump, back-pressure regulator, gas-liquid separator. Procedure:

• Catalyst Presulfidation: Load 10 mL of catalyst into the reactor center, flanked by inert quartz. Activate catalyst by presulfidation with a 3% dimethyldisulfide (DMDS) in diesel stream at 280°C, 40 bar H₂, for 4 hours.
• System Stabilization: Set reactor to target conditions (e.g., 350°C, 120 bar). Establish H₂ flow at 100 mL/min (STP) and allow system to stabilize for 2 hours.
• Feed Introduction: Initiate bio-oil feed via HPLC pump at a Liquid Hourly Space Velocity (LHSV) of 1.0 h⁻¹. Maintain a constant gas-to-liquid ratio (e.g., 1000:1 v/v).
• Product Sampling: Allow 24 hours for system line-out. Collect liquid product from the high-pressure separator every 12 hours. Analyze for water content (Karl Fischer), total acid number (TAN), elemental composition (CHNS/O), and GC-MS for speciation.
• Data Monitoring: Record gas composition (via online GC) to monitor for CO, CO₂, and light hydrocarbons from decarboxylation/decarbonylation.
• Shutdown: Terminate bio-oil feed, continue H₂ flow while cooling to <100°C before depressurization.

Visualizations

3.1 Pathway Diagram

Title: Co-processing Biomass Pathway in Refinery Units

3.2 Experimental Workflow Diagram

Title: Hydroprocessing Experiment Workflow

The Scientist's Toolkit

Table 3: Key Research Reagent Solutions & Materials

Item	Function in Co-processing Research
Equilibrated FCC Catalyst (E-Cat)	Realistic, industry-relevant cracking catalyst containing zeolite Y; used in MAT tests to simulate commercial FCC unit performance.
CoMo/Al₂O₃ & NiMo/Al₂O₃ Catalysts	Standard hydrotreating catalysts for hydrodeoxygenation (HDO) and desulfurization; presulfided before bio-oil experiments.
Microactivity Test (MAT) Unit	Bench-scale fixed-bed reactor system for standardized evaluation of FCC catalyst activity and product selectivity.
Trickle-Bed Reactor System	High-pressure continuous flow reactor simulating industrial hydrotreater hydraulics and catalyst contact modes.
Model Bio-Oil Compounds	Compounds like guaiacol, furfural, or acetic acid used to study specific reaction pathways without feedstock complexity.
Dimethyldisulfide (DMDS)	Common sulfiding agent used in-situ to activate hydrotreating catalysts before introducing reactive bio-oil.
Internal Standards (e.g., Dodecane, DMDS)	Added in precise quantities to feed or product for accurate quantitative GC analysis and yield calculations.
Karl Fischer Titrator	Essential instrument for measuring water content in bio-oils and hydrotreated products, a key metric of HDO efficiency.

Within the research paradigm of co-processing biomass intermediates in petroleum refineries, a systematic assessment of feedstock compatibility is critical. This application note details the protocols for determining blending limits and the requisite pre-treatment methodologies for lignocellulosic bio-oils and pyrolysis oils with conventional petroleum streams. The primary objective is to establish scientifically rigorous boundaries for stable mixture formulation prior to catalytic upgrading in refinery units (e.g., FCC, hydrotreaters).

Table 1: Characteristic Property Ranges of Biomass Intermediates vs. Vacuum Gas Oil (VGO)

Property	Fast Pyrolysis Oil (FP Oil)	Catalytic Pyrolysis Oil (CP Oil)	Hydrothermal Liquefaction (HTL) Biocrude	Typical Petroleum VGO	ASTM Test Method
Density (15°C), kg/m³	1150 - 1250	1000 - 1100	900 - 1050	900 - 950	D4052
Viscosity (40°C), cSt	20 - 100	10 - 40	50 - 500	5 - 15	D445
Oxygen Content, wt%	35 - 45	15 - 25	8 - 18	<0.5	D5622/E385
Water Content, wt%	15 - 30	5 - 15	2 - 8	<0.1	D6304
TAN (Total Acid No.), mg KOH/g	75 - 150	30 - 80	10 - 50	<0.1	D664
HHV (MJ/kg)	16 - 19	22 - 28	30 - 36	40 - 42	D5865
Coking Tendency (MCRT), wt%	15 - 30	10 - 20	5 - 15	0.5 - 2.0	D4530

Table 2: Recommended Blending Limits for Co-processing Stability

Biomass Intermediate	Max Recommended Blend Ratio (vol% with VGO)	Key Limiting Factor	Observation / Failure Mode
FP Oil (Raw)	1 - 5%	High Acidity, Phase Separation	Corrosion, catalyst poisoning, poor miscibility >5%.
CP Oil (Mildly Upgraded)	5 - 15%	Thermal Instability, Olefin Content	Increased coke formation in pre-heaters >15%.
HTL Biocrude (Stabilized)	10 - 20%	Viscosity, Residual Oxygenates	Pumpability issues, reactor plugging at high blends.
Deoxygenated Bio-Oil (HDO)	Up to 25%	Cost, Hydrogen Consumption	Technically feasible at higher ratios; economic limit primary.

Experimental Protocols

Protocol 3.1: Miscibility and Phase Stability Assessment

Objective: To determine the maximum blending ratio before phase separation under refinery-relevant conditions. Materials: Biomass intermediate, base petroleum feedstock (e.g., VGO), heated stirring mantle, graduated cylinders, oven. Procedure:

• Pre-heat petroleum feedstock to 60°C ± 5°C.
• Add biomass intermediate in 1% volume increments under constant shear mixing (500 rpm).
• After each addition, maintain blend at 80°C for 4 hours in a sealed, transparent container.
• Visually inspect for phase separation, haze, or particulate formation.
• Centrifuge a 50 mL sample at 3000 rpm for 15 min (ASTM D2709). Record any separated layer volume.
• The blending limit is defined as the ratio preceding the observation of >0.5 vol% separated phase.

Protocol 3.2: Accelerated Thermal Aging for Stability Prediction

Objective: To assess the chemical stability of blends and predict fouling/coking propensity. Materials: High-pressure batch reactors (Parr), aluminum alloy sample tubes, micro-reactor unit, GC-MS. Procedure:

• Prepare blends at 5%, 10%, and 20% bio-intermediate ratios.
• Load 50 mL of blend into a micro-reactor tube.
• Pressurize with N₂ to 30 bar and heat to 350°C at a rate of 10°C/min. Hold for 2 hours.
• Cool reactor, recover liquid and solid products.
• Filter solids through a pre-weighed 0.45 µm filter. Calculate total insoluble content (wt%).
• Analyze liquid product via Simulated Distillation (ASTM D7169) and GC-MS for compositional changes.

Protocol 3.3: Pre-treatment via Mild Hydrodeoxygenation (HDO)

Objective: To reduce oxygen content and acidity to improve compatibility. Materials: Fixed-bed catalytic reactor, sulfided CoMo/Al₂O₃ or NiMo/Al₂O₃ catalyst, H₂ gas supply, high-pressure pumps. Procedure:

• Condition catalyst at 300°C under 10% H₂S/H₂ for 4 hours.
• Pump raw bio-oil at LHSV of 1.0 h⁻¹.
• Operate reactor at: Temperature = 250-300°C, Pressure = 80-100 bar, H₂/Oil ratio = 500-750 L/L.
• Collect liquid product in a high-pressure separator.
• Analyze product for O-content (Elemental Analyzer), TAN (D664), and water content (D6304).
• Target: Oxygen content <5 wt%, TAN <5 mg KOH/g.

Visualization: Workflows and Pathways

Diagram Title: Feedstock Compatibility Assessment Workflow

Diagram Title: Pre-treatment HDO Reaction Pathways

The Scientist's Toolkit

Table 3: Essential Research Reagent Solutions & Materials

Item / Reagent	Function / Purpose in Compatibility Assessment	Typical Specification / Notes
Model Compound Mix	Simulates key problematic fractions of bio-oil (e.g., acetic acid, guaiacol, furfural).	Used in fundamental miscibility and reactivity studies.
Sulfided CoMo/Al₂O₃ Catalyst	Standard hydrotreating catalyst for pre-treatment HDO experiments.	Pre-sulfided, 1/16" extrudates; requires activation.
Tetralin (1,2,3,4-Tetrahydronaphthalene)	Hydrogen-donor solvent; used in thermal aging tests to distinguish radical coking.	Acts as a free radical scavenger.
Potassium Hydroxide in Isopropanol	Titrant for Total Acid Number (TAN) determination per ASTM D664.	0.1 N KOH solution, must be standardized.
Karl Fischer Reagent (Coulometric)	For precise determination of water content in hygroscopic bio-oils.	Hydranal or equivalent; single-component preferred.
Microreactor System w/ Inconel Liner	Bench-scale simulation of refinery thermal conditions.	Operable to 450°C, 200 bar; resistant to acidic corrosion.
Stable Carbon Isotope-Labeled Compounds	Tracers (e.g., ¹³C-acetic acid) to track oxygen removal pathways.	Used in advanced kinetic and mechanistic studies.

Review of Current Research and Major Pilot/Commercial Projects (2020-Present)

Application Notes: Co-processing Biomass Intermediates in Petroleum Refineries

Technical Rationale and Status

Co-processing involves the simultaneous conversion of biomass-derived intermediates (e.g., pyrolysis oil, hydrotreated vegetable oil) with conventional petroleum streams in existing refinery units, primarily Fluid Catalytic Cracking (FCC) and Hydrotreaters. This leverages existing capital infrastructure to produce partially renewable fuels and chemicals, supporting decarbonization goals. Research from 2020-present has focused on catalyst stability, feedstock pre-treatment, and understanding reaction mechanisms to mitigate challenges like coking, corrosion, and oxygen removal.

Key Research Findings (2020-Present)

Table 1: Summary of Key Pilot and Commercial Co-processing Projects (2020-Present)

Project Name / Lead Organization	Location	Reactor Type	Biomass Intermediate	Co-processing Ratio (Biomass:Oil)	Key Outcome / Yield	Status (as of 2024)
UOP/ENI Ecofining Co-processing	Various (Commercial)	Hydrotreater	HVO, UCO	Up to 25%	High yield of renewable diesel/jet; minimal unit modification.	Commercial
Neste Co-processing	Porvoo, Rotterdam, Singapore	Hydrotreater	PFAD, POME	~10% (initial)	Successful integration into RD production; scalable.	Commercial Operation
TotalEnergies BioTfuel (Demonstration)	France	Hydrotreatment & FCC	Pyrolysis Oil (upgraded)	Varies	Demonstrated full chain from biomass to fuel.	Pilot/Demo Completed (2022)
Ghent University & Valero Study	Belgium (Research)	Micro-Activity Test (MAT) FCC	Pyrolysis Oil (Catalytic)	20%	Increased coke yield (8-12 wt%) vs. VGO; modified catalysts required.	Research Published (2021-23)
Pacific Northwest National Lab (PNNL) & Partners	USA	Continuous Flow Hydrotreater	Pyrolysis Oil (Stabilized)	5-15%	Demonided catalyst deactivation (Fe poisoning) can be managed with guard beds.	Pilot Scale Research
Repsol Innovation Hub	Spain	Pilot FCC	Bio-oil from Wastes	Up to 10%	Successful production of renewable olefins and fuels; focused on feedstock flexibility.	Pilot Active

Table 2: Quantitative Data from Recent Co-processing FCC Research Studies

Study Focus (Year)	Biomass Feed	Co-process %	Coke Yield Increase (vs. base)	Liquid Product Yield	Oxygenate Content in Product	Key Catalyst Modification
Catalytic Pyrolysis Oil in FCC (2022)	Catalytic Pyrolysis Oil	20%	+150% (from 5% to 12.5%)	Decreased by ~15%	<2 wt%	Increased matrix surface area, metal traps
Hydrotreated Pyrolysis Oil (2023)	HPO (2-5 wt% O)	10%	+40%	Comparable to VGO	<0.5 wt%	Zeolite Y with moderate acidity
Raw Pyrolysis Oil (2021)	Raw Pyrolysis Oil	5%	+300% (severe coking)	Severely reduced	>5 wt%	Not effective; pre-treatment essential

Critical Challenges & Solutions

• Catalyst Deactivation: Oxygenates and inorganic contaminants (K, Na, Fe) in bio-oils accelerate catalyst coking and poisoning. Solutions: Advanced feedstock stabilization (mild hydrotreating), use of guard beds, and development of more robust FCC catalysts with tailored matrices.
• Corrosion: Organic acids (e.g., acetic acid) in raw pyrolysis oil cause corrosion. Solution: Material upgrades or, more effectively, hydrodeoxygenation (HDO) pre-treatment.
• Process Integration: Optimizing blending points, operating temperatures, and hydrogen partial pressures is non-trivial. Solution: Advanced process modeling and control strategies developed in recent pilot studies.

Experimental Protocols

Protocol: Microactivity Test (MAT) for FCC Co-processing Evaluation

Aim: To evaluate the product distribution and catalyst deactivation during the co-processing of petroleum vacuum gas oil (VGO) with biomass-derived pyrolysis oil in a simulated FCC environment.

Materials & Equipment:

• Reactor: Fixed-bed MAT unit with isothermal heating.
• Catalyst: Equilibrium FCC catalyst (e.g., Zeolite Y-based), sieved to 75-150 µm.
• Feedstocks: Petroleum VGO (reference), Catalytic Pyrolysis Oil (CPO), blended feeds (e.g., 95:5, 80:20 VGO:CPO).
• Gas Supply: Nitrogen (carrier gas), Air (for coke burn-off).
• Analyzers: Online GC for gaseous products (C1-C5), Refrigerated Receiver for liquid products, CO/CO₂ analyzer for regeneration gas.

Procedure:

• Catalyst Preparation: Load 4.0 g of catalyst into the reactor. Condition at 550°C under N₂ flow (30 mL/min) for 1 hour.
• Reaction: Set reactor temperature to 525°C. Inject a precise mass of feed (typically 1.33 g) via syringe pump over 75 seconds. Maintain N₂ flow.
• Product Collection: Route vapors through a condenser (0°C). Collect liquid product in a sealed receiver for 5 minutes post-injection. Quantify non-condensable gases via online GC.
• Stripping: Purge the catalyst with N₂ for 10 minutes to remove interstitial hydrocarbons.
• Regeneration (Coke Analysis): Switch gas to air. Program temperature to rise to 700°C. Quantify CO and CO₂ produced from coke combustion to calculate coke yield on catalyst.
• Analysis: Weigh liquid product. Analyze by Simulated Distillation (ASTM D7169) and 2D GC (if available) for hydrocarbon speciation. Calculate conversion, yields of gasoline, LCO, and bottoms.

Protocol: Stabilization of Pyrolysis Oil via Mild Hydrotreating for Co-processing

Aim: To reduce the oxygen, acid, and water content of raw pyrolysis oil to produce a stabilized intermediate suitable for refinery hydrotreaters.

Materials & Equipment:

• Reactor: Trickle-bed or continuous flow high-pressure reactor (Parr, Autoclave Engineers).
• Catalyst: Sulfided CoMo/Al₂O₃ or NiMo/Al₂O₃ hydrotreating catalyst (extrudates).
• Feed: Raw woody biomass pyrolysis oil, filtered to <10 µm.
• Gas Supply: Hydrogen (>99.9%), Nitrogen.
• Co-solvent: Hydrocarbon diluent (e.g., light gas oil) to improve pumpability and mixing.

Procedure:

• Feed Preparation: Blend raw pyrolysis oil with 20-30 wt% light gas oil. Homogenize thoroughly.
• Catalyst Activation: Load catalyst into reactor. Activate via in-situ sulfidation using a 3 wt% DMDS in gas oil solution under H₂ pressure (35 bar) at 320°C for 6 hours.
• Reaction Conditions: Set reactor temperature to 250-300°C. Set H₂ pressure to 80-120 bar. Set Liquid Hourly Space Velocity (LHSV) to 1.0-2.0 h⁻¹. Establish H₂-to-oil ratio of 500-1000 L/L.
• Continuous Operation: Pump prepared feed through the pre-heater and reactor. Maintain conditions for a target run length (e.g., 100-200 hours) to assess stability.
• Product Separation: Cool reactor effluent. Separate gas, aqueous phase, and organic phase in a high-pressure separator. Recover the stabilized organic product (Hydrotreated Pyrolysis Oil, HPO).
• Analysis: Characterize HPO for elemental composition (C, H, O), Total Acid Number (TAN), water content, and viscosity. Compare to raw oil.

Visualizations

Title: Biomass Co-processing Pathway from Feedstock to Fuel

Title: Microactivity Test (MAT) Protocol Workflow

The Scientist's Toolkit: Key Research Reagent Solutions

Table 3: Essential Materials for Co-processing Research

Item / Reagent	Function / Application	Key Characteristics / Notes
Equilibrium FCC Catalyst (E-Cat)	Benchmark catalyst for MAT testing; represents real-world, deactivated catalyst.	Contains metal impurities (Ni, V, Fe); defined porosity and acidity. From commercial FCCUs.
Model Oxygenate Compounds	To study specific reaction pathways (e.g., guaiacol for lignin derivatives, acetic acid for corrosion).	High purity (>98%) guaiacol, furfural, anisole, acetic acid. Used in fundamental kinetic studies.
Catalytic Pyrolysis Oil (CPO)	A more consistent biomass intermediate produced with in-situ cracking catalysts.	Lower oxygen (~15 wt%) and acid content than raw bio-oil; better suited for co-processing studies.
Sulfided Hydrotreating Catalysts (CoMo, NiMo)	For bio-oil stabilization (HDO) pre-treatment experiments.	Typically on γ-Al₂O₃ support; require in-situ sulfidation prior to use with bio-oil.
Deactivated Catalyst Standards	To study the effects of specific poisons (K, Na, Fe) on FCC performance.	Laboratory-prepared catalysts with controlled concentrations of contaminant metals.
Internal Standards for GC/MS	For quantitative analysis of complex liquid product streams from co-processing.	Deuterated analogs of aromatics, alkanes, and phenols (e.g., dodecane-d26, phenol-d6).
Porous Absorbents / Guard Bed Media	For pre-removal of inorganic contaminants (alkali metals) from bio-oil vapors/liquids.	Materials like activated alumina, silica gel, or engineered metal traps.

Process Pathways and Implementation: Hydrotreating, Catalytic Cracking, and Hybrid Systems

Hydrodeoxygenation (HDO) for Co-processing in Diesel Hydrotreaters

Within the broader thesis investigating the co-processing of biomass-derived intermediates in existing petroleum refinery infrastructure, Hydrodeoxygenation (HDO) presents a critical catalytic pathway. It enables the conversion of thermally unstable, oxygen-rich bio-oils and fatty acids into stable hydrocarbons suitable for diesel blending. Integrating HDO into conventional diesel hydrotreaters (DHTs) offers a potentially cost-effective route for renewable fuel production but requires careful management of feedstock compatibility, catalyst selection, and process severity to mitigate operational challenges such as catalyst deactivation and exothermic heat release.

Table 1: Typical Properties of Co-processing Feedstocks vs. Petroleum Diesel Feed

Property	Petroleum VGO	Fast Pyrolysis Bio-Oil	Fatty Acids (e.g., Soy)	Hydrotreated Vegetable Oil (HVO)
Oxygen Content (wt%)	<0.5	35-50	10-12	<0.5
Acid Number (mg KOH/g)	~0	50-200	~200	<0.5
Sulfur (ppmw)	10,000-30,000	<100	<10	<10
Heating Value (MJ/kg)	~42	16-20	~37	~44
Density (g/mL)	0.85-0.95	1.1-1.3	0.88-0.90	0.78-0.80
Stability	High	Very Low (Aging)	Moderate	High

Table 2: Catalyst Performance in HDO Co-processing (Bench-Scale)

Catalyst Type	Active Metals	Support	Typical Temp. (°C)	Pressure (bar H₂)	Main Product Yield (C₁₈+)	Key Challenge
Sulfided	NiMo, CoMo	γ-Al₂O₃	300-380	50-100	60-75%	Oxygen removal competes with HDS; water causes sintering.
Non-Sulfided	Pt, Pd, Ru	C, SiO₂, Al₂O₃	250-350	30-80	70-85%	Sulfur in feed can poison noble metals; higher cost.
Bifunctional	Ni, Pt, Pd	Zeolite (e.g., ZSM-5)	300-400	20-50	50-70%	Excessive cracking to gasoline-range; coke formation.

The Scientist's Toolkit: Essential Research Reagents & Materials

Table 3: Key Reagents and Materials for HDO Co-processing Research

Item	Function & Explanation
Model Compound (e.g., Guaiacol, Stearic Acid)	Represents key oxygenate functionalities (e.g., methoxy-phenol, carboxylic acid) in complex bio-oils for fundamental mechanistic studies.
Sulfided Catalyst Precursors (NiMoO₄, CoMoO₄)	Commercial or synthesized precursors that activate in situ under DHT conditions to form the active metal sulfide phases.
Decalin or Dodecane Solvent	High-boiling, inert hydrocarbon medium to dilute viscous bio-feedstocks, improve pumpability, and simulate petroleum blend.
Internal Standard (e.g., Dodecane, Hexadecane)	Added in known quantities to reactant feed for accurate quantification of conversion and yield via Gas Chromatography (GC).
High-Pressure Syringe Pump	Precisely delivers liquid bio-feed/petroleum mixtures against high back-pressure of reactor systems.
Online Micro GC or Refinery Gas Analyzer	Monitors light gases (H₂, CO, CO₂, C₁-C₄) in real-time to track deoxygenation (via CO/CO₂) and cracking pathways.
Simulated Distillation (SimDis) GC	Determines the boiling point distribution of liquid products to assess match with diesel specifications.

Detailed Experimental Protocols

Protocol 1: Catalytic HDO Activity Test in a Trickle-Bed Reactor (Bench-Scale)

• Objective: Evaluate the performance and stability of sulfided CoMo/Al₂O₃ catalyst under co-processing conditions.
• Materials: CoMo/Al₂O₃ catalyst (0.5-1.0 mm pellets), hydrotreated light gas oil (HT-LGO), refined soybean oil, dimethyl disulfide (DMDS), high-purity H₂ (>99.9%), high-pressure syringe pumps, fixed-bed trickle-flow reactor, back-pressure regulator, gas-liquid separator, online GC.
• Procedure:
  • Catalyst Loading & Sulfidation: Load 10-50 cm³ of catalyst pellet into reactor isothermal zone. Under 30 bar H₂ pressure, initiate sulfidation by co-feeding a 2-4 wt% DMDS in LGO solution at 230°C, ramping to 320°C over 8-12 hours. Hold until H₂S breakthrough is stable.
  • Baseline Petroleum Run: Establish baseline by feeding 100% HT-LGO at standard DHT conditions (e.g., 340°C, 80 bar, LHSV 1.5 h⁻¹, H₂/Oil ratio 300 L/L). Collect liquid products every 24h for 72h and analyze for sulfur (ASTM D5453).
  • Co-processing Run: Prepare a blended feed of 95 vol% HT-LGO and 5 vol% soybean oil. Switch feed to this blend, maintaining identical process conditions. Collect liquid products at 6h, 12h, 24h, and then daily.
  • Product Analysis: Analyze liquid products for total acid number (TAN, ASTM D664), oxygen content (via elemental analysis or GC×GC), cloud point (ASTM D5773), and simulated distillation. Quantify gas-phase CO, CO₂, and C₁-C₄ via online GC.
  • Shutdown & Catalyst Analysis: After 200-500 hours on stream, purge reactor with H₂, then N₂, and cool. Recover catalyst for post-mortem analysis (TGA for coke, XPS for surface species, SEM for morphology).

Protocol 2: Accelerated Thermal Stability & Compatibility Test for Feed Blends

• Objective: Assess the propensity of bio-oil/petroleum blends to form gums, sediments, or phase separation under thermal stress.
• Materials: Fast pyrolysis bio-oil (stabilized), straight-run gas oil, filtration setup (0.8 μm membrane), aging cell (Bomb-type), oven.
• Procedure:
  • Blend Preparation: Create blends (e.g., 2%, 5%, 10% bio-oil) in gas oil using high-shear mixing for 15 minutes. Filter a sample of each fresh blend to determine initial particulate content (ASTM D4870).
  • Thermal Aging: Charge 100 mL of each blend into separate aging cells. Pressurize with N₂ to 5 bar and place in an oven pre-heated to 100°C for 168 hours (1 week).
  • Post-Aging Analysis: Cool cells to room temperature. Visually inspect for phase separation. Filter the entire contents through a pre-weressed 0.8 μm membrane. Dry and weigh the filter to determine total insoluble sediment (mg/100mL). Measure TAN and viscosity of the filtered liquid.
  • Compatibility Rating: Blends showing >10 mg/100mL sediment or significant viscosity increase are deemed high-risk for fouling pre-heat exchangers and reactor tops in commercial units.

Visualization: Pathways and Workflows

Diagram 1: HDO Co-processing in a DHT Unit

Diagram 2: HDO Co-processing Reseach Workflow

Fluid Catalytic Cracking (FCC) Unit Integration with Biomass-Derived Feeds

This application note is framed within a broader research thesis on co-processing biomass intermediates in petroleum refineries. The objective is to systematically evaluate the technical feasibility and catalytic implications of integrating pyrolysis oil (bio-oil) and hydrotreated vegetable oil (HVO) into the conventional FCC feedstock slate. The FCC unit, a central conversion asset, presents a pivotal opportunity for biorenewable integration, demanding rigorous protocols for feedstock characterization, catalyst testing, and product analysis.

Key Research Data & Comparison

The following tables summarize critical quantitative findings from recent studies on FCC co-processing.

Table 1: Typical Properties of Biomass-Derived Feeds vs. Conventional VGO

Property	Conventional VGO	Fast Pyrolysis Bio-Oil	Hydrotreated Vegetable Oil (HVO)
Oxygen Content (wt%)	<0.5	35-50	<1
Hydrogen Content (wt%)	~12	6-7	~15
Density (kg/m³)	900-920	1100-1300	770-780
Acidity (TAN, mg KOH/g)	<0.1	50-100	<0.1
Final Boiling Point (°C)	>500	~300 (Non-volatile fraction)	~350

Table 2: Co-processing Performance Summary (10 wt% Biomass Feed Blend)

Performance Metric	VGO Base Case	VGO + Raw Bio-Oil	VGO + Catalytic Pyrolysis Oil	VGO + HVO
Conversion (wt%)	75-80	68-72	74-78	78-82
Dry Gas Yield (wt%)	3-4	5-8	4-5	2-3
LPG Yield (wt%)	15-18	12-15	16-18	18-20
Gasoline Yield (wt%)	45-50	38-42	44-48	48-52
Coke Yield (wt%)	5-6	8-12	6-7	4-5
Olefinicity (C₃⁺/C₃⁰)	6-8	4-6	6-7	8-10

Experimental Protocols

Protocol: Feedstock Pre-treatment and Stabilization

• Objective: To reduce oxygen content and acidity of raw bio-oil via mild hydrodeoxygenation (HDO) to produce a stable, co-processable feed.
• Materials: Raw pyrolysis oil, fixed-bed reactor system, sulfided CoMo/Al₂O₃ catalyst, H₂ gas.
• Methodology:
  • Load 50 mL of catalyst into a fixed-bed reactor (300°C, 5 MPa H₂).
  • Feed raw bio-oil at LHSV of 2.0 h⁻¹ with an H₂/oil ratio of 600 L/L.
  • Maintain reaction temperature at 250-300°C.
  • Collect liquid product in a cold separator and analyze for oxygen content (ASTM D5622) and Total Acid Number (TAN, ASTM D664).
• Success Criteria: Oxygen content <10 wt%; TAN <5 mg KOH/g.

Protocol: Microactivity Test (MAT) for Catalyst Screening

• Objective: To evaluate the catalytic cracking performance of equilibrated FCC catalyst (E-CAT) with blended feeds.
• Materials: ASTM standard MAT unit, E-CAT sample, blended feed (e.g., 95/5 VGO/Stabilized Bio-Oil).
• Methodology:
  • Fix 4.0 g of E-CAT in the reactor. Preheat to reaction temperature (525°C).
  • Inject 1.33 g of blended feed via syringe pump over 75 seconds (Cat/Oil = 3).
  • Crack products are carried to an online GC for detailed hydrocarbon analysis.
  • Coke yield is determined by burning off spent catalyst in a separate regenerator and measuring CO₂.
• Success Criteria: Test reproducibility within ±1.5% for conversion.

Protocol: Accelerated Catalyst Deactivation (Steaming)

• Objective: To simulate catalyst aging and assess tolerance to biomass-derived contaminants (e.g., alkali metals).
• Materials: Fresh FCC catalyst, steam generator, tube furnace.
• Methodology:
  • Impregnate fresh catalyst with 1000 ppm K (as KNO₃ solution) via incipient wetness.
  • Place 10 g of catalyst in a fluidized bed steamer.
  • Expose to 100% steam at 800°C for 4-8 hours.
  • Perform MAT (Protocol 3.2) on the steamed catalyst and compare activity retention (% of baseline).
• Success Criteria: Quantify relative activity loss vs. non-impregnated steamed catalyst.

Diagrams & Visual Workflows

FCC Co-processing Feedstock Integration Workflow

Experimental Protocol Sequence for FCC Co-processing Research

The Scientist's Toolkit: Key Research Reagent Solutions

Item	Function in Co-processing Research
Equilibrated FCC Catalyst (E-CAT)	Realistic, industry-relevant catalyst sample containing metal contaminants, used in MAT and deactivation studies.
ZSM-5 Additive	Shape-selective zeolite additive used to boost light olefin (propylene) yield during co-processing.
Potassium Nitrate (KNO₃) Solution	Used for deliberate contamination of catalyst to study deactivation by alkali metals present in biomass feeds.
Tetralin (1,2,3,4-Tetrahydronaphthalene)	Model hydrogen-donor solvent used in exploratory studies to suppress thermal coking from bio-oil.
Deactivated Alumina (α-Al₂O₃)	Inert diluent used in fixed-bed reactors during pre-treatment studies to manage exotherms and bed volume.
Sulfided CoMo/Al₂O₃ Catalyst	Standard hydrotreating catalyst used for bio-oil stabilization via mild hydrodeoxygenation (HDO).
Internal Standards (e.g., Dodecane, Hexamethylbenzene)	For quantitative gas chromatography (GC) analysis of liquid products and coke yield determination, respectively.

The integration of renewable carbon into existing petroleum refinery infrastructure is a cornerstone of modern biorefinery research. This work, framed within a broader thesis on Co-processing biomass intermediates in petroleum refineries, addresses a central challenge: the inherent instability and high oxygen content of raw bio-oils and pyrolysis oils, which cause polymerization, corrosion, and catalyst poisoning in refinery units. The two-stage processing approach decouples stabilization from deep upgrading. An initial Mild Hydrodeoxygenation (HDO) stage selectively removes the most reactive oxygen species, stabilizing the intermediate. A subsequent Deep Upgrading stage, often under more severe conditions or with different catalysts, achieves near-complete deoxygenation and cracking to produce refinery-ready hydrocarbons. This methodology enhances process control, improves catalyst longevity, and maximizes yield of targeted fuel-range products.

Application Notes

Note A: Rationale for Stage Decoupling. Mild HDO (typically 200-300°C, 20-70 bar H₂) targets carboxylic acids, aldehydes, and ketones, preventing acidic corrosion and resin formation. Deep upgrading (typically 300-400°C, 70-150 bar H₂) focuses on recalcitrant oxygenates (e.g., phenolics) and C-C bond scission. This prevents excessive hydrogen consumption and coke formation in a single, overly severe step.

Note B: Catalyst Selection Strategy.

• Stage 1 (Mild HDO): Sulfided CoMo/Al₂O₃ or NiMo/Al₂O₃ catalysts are common, offering good resistance to sulfur impurities. Recent research focuses on supported noble metals (Pt, Pd, Ru) on moderate-acidity supports (e.g., TiO₂, ZrO₂) for higher activity at lower temperatures.
• Stage 2 (Deep Upgrading): Bifunctional catalysts combining a hydrogenation/dehydrogenation metal (Pt, Pd, Ni) with a solid acid (Zeolites like HZSM-5, HBEA) are prevalent. The acid site facilitates cracking, isomerization, and dehydration, while the metal site supplies hydrogen and prevents coking.

Note C: Co-processing Compatibility. The stabilized bio-intermediate from Stage 1 possesses improved hydrophobicity and thermal stability, enabling its direct blending with petroleum streams (e.g., vacuum gas oil) for co-feeding into Fluid Catalytic Cracking (FCC) or Hydroprocessing units in Stage 2. This leverages existing refinery scale and efficiency.

Table 1: Comparative Performance of Single-Stage vs. Two-Stage Upgrading of Pine Wood Pyrolysis Oil.

Parameter	Raw Bio-Oil	Single-Stage Severe HDO	Two-Stage: Mild HDO Output	Two-Stage: Final Product
Processing Conditions	-	400°C, 120 bar H₂	Stage 1: 250°C, 50 bar H₂	Stage 2: 350°C, 100 bar H₂
Oxygen Content (wt%)	40-50%	<5%	15-20%	<3%
Total Acid Number (mg KOH/g)	60-100	<5	<10	<1
Water Content (wt%)	15-30%	<2%	5-10%	<1%
Higher Heating Value (MJ/kg)	16-19	42-44	35-38	43-45
Coke Yield (wt% on cat.)	-	High (15-25%)	Low (<5%)	Moderate (5-10%)
Overall C7+ Hydrocarbon Yield	-	25-35%	-	40-50%

Table 2: Representative Catalysts and Their Functions in Two-Stage Processing.

Stage	Catalyst Example	Primary Function	Key Reaction Pathways
1. Mild HDO	5% Ru/TiO₂	Selective Hydrogenation	R-COOH → R-CHO → R-CH₂OH; R-CHO → R-CH₃ + H₂O
1. Mild HDO	Sulfided NiMo/γ-Al₂O₃	Hydrotreating, HDO	Removal of S, O, N heteroatoms; saturation of olefins
2. Deep Upgrading	1% Pt/HZSM-5	Hydrocracking, Aromatization	C-C cleavage, dehydrocyclization, isomerization
2. Deep Upgrading	Ni-W/SiO₂-Al₂O₃	Hydroprocessing	Severe HDO, hydrodearomatization, saturation

Experimental Protocols

Protocol 1: Mild HDO Stabilization of Fast Pyrolysis Bio-oil.

• Objective: To partially deoxygenate bio-oil, reducing acidity and reactivity for improved stability.
• Materials: Raw pine pyrolysis oil, sulfided NiMo/Al₂O₃ catalyst (250-500 µm), high-pressure fixed-bed reactor, H₂ gas, condensers, liquid product collectors.
• Procedure:
  • Load 10.0 g of catalyst into the isothermal zone of a fixed-bed reactor. Pre-reduce catalyst under H₂ flow (100 mL/min) at 300°C for 2 hours.
  • Set reactor temperature to 250°C and pressure to 50 bar under H₂ flow.
  • Feed raw bio-oil via HPLC pump at a weight hourly space velocity (WHSV) of 1.0 h⁻¹ with a H₂/oil ratio of 500 mL/mL (STP).
  • Maintain reaction for 6 hours, collecting liquid products in a cooled trap. Separate aqueous and organic phases.
  • Analyze the organic phase (stabilized oil) for: Total Acid Number (ASTM D664), elemental composition (CHNS/O), water content (Karl Fischer), and GC-MS for composition.
  • Stability Test: Hold a sample at 80°C for 24h and measure viscosity change. Stabilized oil should show <20% increase vs. >100% for raw bio-oil.

Protocol 2: Deep Hydrocracking/Upgrading of Stabilized Bio-Oil.

• Objective: To convert stabilized bio-oil into hydrocarbon fuels.
• Materials: Stabilized oil from Protocol 1, Pt/HZSM-5 (1 wt% Pt, Si/Al=40) catalyst, same reactor system.
• Procedure:
  • Load 5.0 g of Pt/HZSM-5 catalyst. Activate under H₂ at 400°C for 3 hours.
  • Set reactor to 350°C and 100 bar H₂.
  • Feed the stabilized bio-oil at WHSV of 1.5 h⁻¹ and H₂/oil ratio of 800 mL/mL.
  • Collect liquid and gas products over a 4-hour period. Quantify gas yield via wet gas meter and analyze by online GC (TCD/FID).
  • Recover liquid product, measure yield, and analyze via Simulated Distillation (ASTM D7169) to determine boiling point distribution and fuel fraction yield (C5-350°C).
  • Characterize spent catalyst for coke content via Thermogravimetric Analysis (TGA).

Visualization: Workflow & Pathway Diagrams

Diagram Title: Two-Stage Bio-Oil Upgrading Process Flow

Diagram Title: Key Reaction Pathways in Two-Stage HDO

The Scientist's Toolkit: Research Reagent Solutions

Table 3: Essential Materials for Two-Stage Upgrading Experiments

Item	Function & Rationale
Sulfided NiMo/Al₂O₃ Pellets	Benchmark Stage 1 catalyst. Provides hydrotreating activity, tolerates bio-oil impurities. Must be pre-sulfided.
Pt/HZSM-5 Powder (1% Pt)	Prototypical Stage 2 bifunctional catalyst. Pt sites hydrogenate, zeolite acid sites crack and isomerize.
Fixed-Bed Microreactor System	Bench-scale continuous flow system with precise T/P control, essential for mimicking industrial process conditions.
High-Pressure HPLC Pump	Precisely meters viscous, unstable bio-oil feedstocks into the high-pressure reactor environment.
Online Micro-GC with TCD/FID	For real-time analysis of light gases (H₂, CO, CO₂, C1-C6) produced during reaction, critical for mass balance.
Karl Fischer Coulometric Titrator	Precisely measures trace water content in feed and products, a key metric for deoxygenation efficiency.
Simulated Distillation (SimDis) GC	Determines the boiling point distribution of liquid products, quantifying yield of gasoline, diesel, and jet fuel ranges.

Catalyst Selection and Formulation for Oxygenate Removal and Coke Management

Co-processing biomass-derived intermediates (e.g., pyrolysis oil, hydrotreated vegetable oil) in existing petroleum refinery units, such as fluid catalytic cracking (FCC), is a promising route for biofuel production. This research is a core component of a broader thesis aiming to achieve economically viable and sustainable integration. A primary technical challenge is the high oxygenate content of biomass feeds, which leads to excessive coke formation, catalyst deactivation, and undesirable product profiles. This Application Note details catalyst selection and formulation strategies specifically targeted at enhancing oxygenate removal (hydrodeoxygenation - HDO) and managing coke deposition during co-processing.

Key Catalyst Functions and Performance Data

Effective catalysts must balance multiple functions. Quantitative data from recent studies is summarized below.

Table 1: Performance of Catalyst Formulations for Model Oxygenate Conversion

Catalyst Formulation	Target Oxygenate	Temp. (°C)	Pressure (bar)	O-Removal (%)	Coke Yield (wt%)	Key Finding	Ref.
Pt/Al₂O₃	Acetic Acid	300	30	99.5	0.8	High decarboxylation, low coke.	[1]
NiMo/Al₂O₃	Guaiacol	350	50	95.2	4.1	Good HDO, modest coke.	[2]
HZSM-5 (Zeolite)	Anisole	450	1 (N₂)	88.7	12.5	High aromatics, severe coking.	[3]
Pt/HZSM-5	Anisole	400	30	99.1	3.2	Bifunctionality reduces coke.	[4]
Co/SBA-15 (Mesoporous)	Furfural	250	20	92.0	1.5	Mesoporosity aids coke management.	[5]

Table 2: Co-processing FCC Catalyst Additives Evaluation

Additive Type	Base Catalyst	Biomass Feed %	Conv. (%)	Δ Coke (rel. to base)	Δ Gasoline O (ppm)	Function	Ref.
La-ZSM-5	REUSY	10% PyOil	+2.1	+15%	-205	Mild cracking, some O-removal.	[6]
MgO-Al₂O₃	REUSY	20% HVO	-1.5	-25%	-150	Basic sites neutralize acids, reduce coking.	[7]
P-Modified Zeolite Beta	REUSY	15% PyOil	+0.5	-30%	-320	Passivates strong acid sites, enhances HDO.	[8]

Experimental Protocols

Protocol 3.1: Catalyst Synthesis via Wet Impregnation (e.g., NiMo/Al₂O₃)

Objective: To prepare a supported metal sulfide catalyst for hydrodeoxygenation (HDO). Materials: γ-Alumina support (high surface area, 250 m²/g), Ammonium heptamolybdate tetrahydate, Nickel(II) nitrate hexahydrate, Deionized water. Procedure:

• Pore Volume Calculation: Determine the water pore volume of the alumina support (typically ~0.8 mL/g) using a standard water adsorption test.
• Solution Preparation: Dissolve stoichiometric amounts of Mo and Ni precursors (e.g., for 12 wt% MoO₃, 3 wt% NiO) in deionized water equal to 95% of the support's pore volume.
• Impregnation: Slowly add the aqueous solution dropwise to the alumina powder under continuous manual stirring in an evaporating dish.
• Drying: Place the dish in a static oven at 120°C for 12 hours.
• Calcination: Transfer the dried material to a muffle furnace. Heat in air from room temperature to 500°C at a ramp rate of 5 °C/min and hold for 4 hours.
• Sulfidation (Pre-treatment): Load calcined catalyst into a fixed-bed reactor. Activate under a flow of 10% H₂S/H₂ at 350°C for 4 hours prior to HDO testing.

Protocol 3.2: Fixed-Bed Reactor Evaluation of Oxygenate Conversion & Coke Deposition

Objective: To assess catalyst activity, selectivity, and coking tendency under controlled conditions. Materials: Synthesized catalyst (sized to 150-250 μm), Model oxygenate (e.g., guaiacol) in hydrocarbon solvent (e.g., dodecane), High-pressure H₂, On-line GC/MS, Thermogravimetric Analyzer (TGA). Procedure:

• Reactor Loading: Pack 0.5 g of catalyst (diluted 1:5 with inert SiC) into the isothermal zone of a stainless-steel tubular reactor (ID = 6 mm).
• Leak Testing & Pre-treatment: Pressure-test the system with N₂. Perform in-situ sulfidation (Protocol 3.1, Step 6) or reduction in H₂ as required.
• Reaction Conditions: Set temperature (300-400°C), pressure (30-50 bar), and H₂ flow rate (e.g., 100 mL/min). Initiate liquid feed (model compound, 1-5 wt%) via HPLC pump at a desired weight hourly space velocity (WHSV, e.g., 2 h⁻¹).
• Product Analysis: After 1 hour stabilization, collect liquid and gaseous products. Analyze via GC-MS for oxygenate conversion and product distribution. Quantify water yield via Karl Fischer titration.
• Coke Quantification (Post-run): a. Cool reactor under inert flow (N₂). b. Recover spent catalyst carefully. c. Perform TGA analysis: Heat ~20 mg spent catalyst from 100°C to 800°C in air (ramp 10 °C/min). The weight loss in the 350-650°C range is attributed to combustion of deposited coke.

Protocol 3.3: Accelerated Deactivation Testing for FCC Co-processing

Objective: To simulate long-term coking and deactivation in a microactivity test (MAT) unit. Materials: Equilibrium FCC catalyst (E-Cat), Biomass intermediate (e.g., stabilized pyrolysis oil), VGO feedstock, MAT reactor system with online product analysis. Procedure:

• Catalyst/Feed Blending: Prepare a feed blend containing 10-20 wt% biomass intermediate in conventional vacuum gas oil (VGO).
• Baseline MAT: Conduct a standard MAT run (ASTM D3907) with pure VGO on the E-Cat at 520°C, catalyst-to-oil ratio (CTO) of 3, to establish baseline conversion and yield profile.
• Co-processing MAT: Repeat MAT run under identical conditions using the biomass-VGO blend.
• Repeat Injection (Deactivation Cycle): Perform 5-10 consecutive MAT injections on the same catalyst charge, regenerating with air at 550°C for 10 minutes between each run. This simulates the FCC unit's cyclic operation.
• Analysis: Monitor the decline in conversion and increase in coke yield relative to baseline over the cycles. Characterize spent catalyst via N₂ physisorption (surface area/pore volume loss) and FTIR or NH₃-TPD (acid site characterization).

Visualization: Pathways and Workflows

Title: Oxygenate Pathways & Catalyst Strategy Map

Title: Catalyst R&D Workflow for Co-processing

Title: Surface Reaction Network: HDO vs. Coking

The Scientist's Toolkit: Research Reagent Solutions

Table 3: Essential Materials and Reagents for Catalyst Research

Item	Function/Description	Key Consideration for Co-processing Research
Model Oxygenates	Representative compounds for controlled experiments.	Guaiacol (phenolic), Furfural (aldehyde), Acetic Acid (carboxylic acid) cover major O-species.
Zeolite Supports (HZSM-5, HY, Beta)	Provide strong Brønsted acidity for cracking.	Must be modified (e.g., with P, La) to temper acidity and reduce coking from oxygenates.
Mesoporous Supports (SBA-15, Al-MCM-41)	High surface area, tunable pores >2 nm.	Facilitates diffusion of bulky biomass molecules, reduces pore-mouth coking.
Metal Precursors	Source of active HDO metals.	Ni, Mo, Co, W for sulfide catalysts; Pt, Pd, Ru for noble metal catalysts.
Sulfiding Agent (e.g., Dimethyl Disulfide - DMDS)	In-situ source of H2S for activating metal sulfide catalysts.	Critical for maintaining active sulfided phase under HDO conditions.
Stabilized Pyrolysis Oil (Bio-Oil)	Real biomass intermediate for co-processing tests.	Must be homogenized and filtered; high water and solids content can be challenging.
Thermogravimetric Analyzer (TGA)	Quantifies coke burn-off and catalyst stability.	Use air atmosphere for coke combustion; correlate weight loss with deactivation.
NH₃-TPD System	Measures catalyst acidity (amount & strength).	Strong acid sites correlate with coking; monitor their reduction after modification.
Microactivity Test (MAT) Unit	Bench-scale simulator of FCC process.	Enables rapid, cyclic testing of catalyst deactivation under co-processing conditions.

This document provides detailed application notes and protocols for experiments related to the co-processing of biomass-derived intermediates in existing petroleum refinery units. This work is framed within a broader thesis research program aiming to de-fossilize the transportation fuel and chemical sectors by integrating sustainable carbon feedstocks. The focus is on practical, scalable data from integrated pilot or demonstration runs, providing a critical bridge between fundamental catalysis research and commercial implementation for an audience of researchers, scientists, and process development professionals.

Case Study Summaries & Data Tables

Data synthesized from recent integrated runs demonstrate the viability and challenges of co-processing.

Table 1: Operational Parameters for Representative Co-processing Runs

Case Study	Reactor Type	Primary Petroleum Feed	Biomass Intermediate	Co-processing Ratio (wt%)	Temperature (°C)	Pressure (MPa)	Catalyst
Fast Pyrolysis Oil in FCC [1]	Fluid Catalytic Cracker	Vacuum Gas Oil	Catalytic Fast Pyrolysis Oil	20%	525-550	0.2	Zeolite (ZSM-5 based)
Hydrotreated Vegetable Oil (HVO) in Hydrocracker [2]	Fixed-Bed Hydrocracker	Heavy Vacuum Gas Oil	Hydrotreated Vegetable Oil	10%	370-390	15.0	NiMo/Al₂O₃
Catalytic Pyrolysis Oil in Hydrotreating [3]	Trickle-Bed Hydrotreater	Straight-Run Gas Oil	Stabilized Pyrolysis Oil	5%	350	8.5	CoMo/Al₂O₃
Lignin Oil in Fluid Catalytic Cracking [4]	Advanced Catalytic Cracking	Atmospheric Residue	Depolymerized Lignin Oil	15%	500	0.15	Equilibrium FCC Catalyst

Table 2: Yields and Product Distribution from Integrated Runs

Case Study	Total Liquid Yield (wt%)	Deoxygenation Efficiency (%)	Gas Yield (wt%)	Coke Yield (wt%)	Key Product Distribution (within Liquid)	Notes
Fast Pyrolysis Oil in FCC [1]	68.2	~95 (as CO/CO₂)	18.5	8.3	Gasoline: 42%, LCO: 18%, Olefins: 12%	High coke yield; Olefinicity increased.
HVO in Hydrocracker [2]	94.5	100 (Pre-hydrotreated)	4.1	<0.5	Jet Fuel: 38%, Diesel: 55%	Excellent yield, drop-in quality products.
Pyrolysis Oil in Hydrotreating [3]	78.0	88	15.2	1.8	Diesel-Range: 65%, Naphtha: 25%	Catalyst deactivation rate 2x baseline.
Lignin Oil in FCC [4]	62.8	91	22.0	10.2	Aromatics (BTX): 28%, Gasoline: 35%	High aromatic selectivity; severe coking.

Experimental Protocols

Protocol 3.1: Integrated Co-processing in a Microactivity Test (MAT) FCC Unit

Objective: To evaluate the performance and product slate of co-processing catalytic fast pyrolysis (CFP) oil with vacuum gas oil (VGO) under standard FCC conditions. Materials: See Scientist's Toolkit. Procedure:

• Feed Preparation: Homogenize the CFP oil (stored at 4°C) and warm to 30°C. Mix thoroughly with pre-heated VGO (60°C) at the target co-processing ratio (e.g., 20:80 wt%) using a high-shear mixer for 30 minutes.
• Reactor Setup: Load 4.0 g of equilibrium FCC catalyst into the fixed fluidized-bed MAT reactor. Condition the catalyst under N₂ flow (30 cc/min) at 538°C for 1 hour.
• Run Execution: Inject 1.33 g of the blended feed via a syringe pump into the catalyst bed over 75 seconds. Maintain reactor temperature at 525°C.
• Product Collection: Liquid products are condensed in a chilled receiver (0°C). Non-condensable gases are collected in a gas bag for GC-TCD/FID analysis. Spent catalyst is recovered for coke measurement by combustion in a TGA.
• Analysis: Weigh liquid and water phases. Analyze liquid by Simulated Distillation (ASTM D2887) and detailed hydrocarbon analysis (GCxGC). Analyze gas composition via GC.

Protocol 3.2: Fixed-Bed Hydrocracker Co-processing Run

Objective: To assess the yield of jet/diesel range hydrocarbons from co-processing hydrotreated vegetable oil (HVO) with heavy VGO. Procedure:

• Catalyst Loading & Activation: Load a stacked-bed configuration (hydrotreating catalyst top, hydrocracking catalyst bottom) into a high-pressure fixed-bed reactor. Sulfidize the catalyst in-situ using a dimethyldisulfide (DMDS)/gas oil feed at 320°C and 8 MPa for 24 hours.
• Baseline Run: Establish baseline performance by processing 100% HVGO at standard conditions (375°C, 15 MPa, LHSV 1.0 h⁻¹, H₂/oil ratio 1000 NL/L).
• Co-processing Run: Switch feed to the pre-mixed blend (10% HVO, 90% HVGO). Maintain identical operating conditions. Allow 48 hours for line-out before collecting data over a 72-hour period.
• Sampling & Analysis: Collect liquid product samples every 24 hours. Analyze for sulfur, nitrogen, density, and cetane/index. Determine boiling point distribution via SimDist. Monitor H₂ consumption from gas recycle loop.
• Shutdown: After run, purge reactor with H₂, then N₂ before cooling to room temperature. Recover catalyst for post-mortem analysis (e.g., TPO, TEM).

Visualizations

Diagram 1: Co-processing Experimental Workflow

Diagram 2: Biomass Intermediate Upgrading Pathways

The Scientist's Toolkit: Essential Research Reagents & Materials

Table 3: Key Research Reagent Solutions and Materials

Item	Function/Application	Key Characteristics/Notes
Equilibrium FCC Catalyst (E-CAT)	The working catalyst in MAT tests; mimics commercial unit activity/selectivity.	Contains metal impurities (Ni, V) from refinery use; defines baseline performance.
Model Bio-Oil Compounds	(e.g., Guaiacol, Acetic Acid, Furfural) Used for fundamental reactivity studies.	Simplifies complex bio-oil; allows for precise kinetic and mechanistic analysis.
Dimethyldisulfide (DMDS)	Standard in-situ sulfiding agent for activating hydroprocessing catalysts.	Decomposes at ~200°C to provide H₂S, required to convert metal oxides to active sulfides.
Internal Standards (for GC)	(e.g., Dodecane, Biphenyl, Fluoranthene) For quantitative product analysis.	Must be inert and elute in a clear region of the chromatogram relative to products.
Deoxygenation Monitor Solution	A calibrated mix of oxygenates in decane. Used for GC response factor determination.	Critical for accurately quantifying low levels of residual oxygen in products.
High-Pressure H₂ Gas (≥99.99%)	Reactant and purge gas in hydroprocessing experiments.	Ultra-high purity minimizes catalyst poisoning by CO or other contaminants.
Reference Petroleum Feeds	Well-characterized VGO, Atmospheric Gas Oil. Provide consistent baseline for comparison.	ASTM certified properties (S, N, density, boiling curve) are essential.

Overcoming Key Challenges: Catalyst Deactivation, Corrosion, and Process Economics

The co-processing of biomass-derived intermediates (e.g., pyrolysis oil, hydroprocessed esters and fatty acids) with conventional petroleum streams in existing refinery units presents a promising path for renewable fuel production. However, this strategy introduces unique catalyst deactivation challenges. Biomass feeds often contain high oxygenates, alkali/alkaline earth metals, and unsaturated compounds that exacerbate coke formation, metal poisoning, and polymerization. This article details application notes and protocols for studying and mitigating these deactivation pathways, critical for the techno-economic viability of co-processing.

Mechanisms and Quantitative Data

Table 1: Common Catalyst Poisons in Co-processing Feeds and Their Effects

Poison Source (Biomass Feed)	Typical Contaminant	Primary Deactivation Mode	Approximate Tolerance Limit (wt% on catalyst)	Regeneration Potential
Pyrolysis Bio-oil	Organic Oxygenates (Acids, Aldehydes)	Coke via polymerization	N/A (Kinetic driven)	Partial via oxidative burn-off
Agricultural Residues	K, Na, Ca (Alkali Metals)	Active site blockage, pore plugging	0.5-2%	Irreversible
Tall Oil, Animal Fats	Phosphorus, Metals (Ca, Mg)	Acid site neutralization	<0.1%	Irreversible
All Biomass	Unsaturated Hydrocarbons (Diolefins)	Coke precursor, polymer formation	Varies	Partial via hydrogenation

Table 2: Catalyst Performance Decay in Co-processing Experiments

Catalyst Type	Process	Biomass Blend Ratio	Time-on-Stream to 50% Activity Loss (h)	Primary Deactivation Cause	Ref
NiMo/Al2O3	Hydrotreating	20% Pyrolysis Oil	~200	Coke (Polymerized oxygenates)	[1]
FCC Catalyst	Fluid Catalytic Cracking	10% HDO Oil	~150	Coke, Zeolite Unit Cell Damage	[2]
Pt/SAPO-11	Hydroisomerization	30% HEFA	~400	Mild Coke, Metal Agglomeration	[3]

Experimental Protocols

Protocol 1: Accelerated Coking Test for Catalyst Screening

Objective: To evaluate and rank catalyst formulations for coke resistance under co-processing conditions. Materials: Fixed-bed microreactor, HPLC pumps, mass flow controllers, candidate catalysts (e.g., Pt/Al2O3, Zeolite-based), model feed (20% furfural in decane), hydrogen gas. Procedure:

• Catalyst Loading: Sieve catalyst to 150-250 µm. Load 0.5 g into reactor tube sandwiched between quartz wool.
• Pre-treatment: Activate catalyst under 50 mL/min H2 at 400°C for 2 hours.
• Reaction: Switch to model feed at 2 mL/h liquid flow with 100 mL/min H2 (350°C, 30 bar). Run for 24h.
• Analysis: Perform Temperature-Programmed Oxidation (TPO) on spent catalyst to quantify coke burn-off temperature and amount using online MS (CO2 signal). Key Metrics: Coke yield (mg coke/g cat), TPO peak temperature (indicates coke graphiticity).

Protocol 2: Metals Deposition and Poisoning Study

Objective: To simulate and quantify irreversible deactivation by biomass-borne metals. Materials: Laboratory-scale hydrotreater, aqueous solutions of K, Ca, or P salts, vacuum gas oil (VGO), reference catalyst (e.g., CoMo/Al2O3). Procedure:

• Impregnation: Impregnate fresh catalyst pellets with 1-5 wt% metal via incipient wetness using nitrate or acetate salts. Dry and calcine.
• Activity Test: Evaluate initial activity of fresh and metal-doped catalysts in hydrodesulfurization (HDS) of model compound (dibenzothiophene) at standard conditions (340°C, 40 bar).
• Post-mortem: Use SEM-EDX and XPS to map metal distribution on spent catalyst particles. Key Metrics: % Loss in HDS activity relative to fresh catalyst, metal penetration depth profile.

Protocol 3: Mitigation via Guard Beds and Pre-treatment

Objective: To test the efficacy of upstream protection for the primary catalyst. Materials: Dual-bed reactor, guard bed materials (activated carbon, low-cost adsorbent, sacrificial catalyst), co-processing feed (10% bio-oil, 90% VGO). Procedure:

• Setup: Pack guard material (2 g) in upstream bed, primary hydrotreating catalyst (1 g) in downstream bed.
• Operation: Run co-processing feed under typical conditions (370°C, 80 bar H2) for 100h.
• Analysis: Compare product quality (e.g., O, S content) and pressure drop across beds over time. Analyze spent guard bed for trapped contaminants via ICP-OES. Key Metrics: Extension of primary catalyst lifetime, contaminant capture capacity of guard bed (mg contaminant/g sorbent).

The Scientist's Toolkit

Table 3: Key Research Reagent Solutions for Deactivation Studies

Reagent/Material	Function in Experiment	Typical Supplier/Example
Dibenzothiophene (DBT)	Model sulfur compound for tracking HDS activity loss due to poisoning	Sigma-Aldrich, >98% purity
Furfural / Guaiacol	Model oxygenate compounds to induce controlled coke formation	TCI Chemicals, reagent grade
Potassium Nitrate (KNO3)	Aqueous precursor for simulating alkali metal poisoning	VWR Chemicals
Temperature-Programmed Oxidation (TPO) System	Quantifies amount and type of coke on spent catalysts	Micromeritics AutoChem
Tetralin (1,2,3,4-Tetrahydronaphthalene)	Hydrogen-donor solvent to suppress thermal coke in experiments	Alfa Aesar, 95%

Visualizations

Title: Coke Formation Pathway from Biomass Oxygenates

Title: Mitigation Strategy Framework for Catalyst Deactivation

Title: Co-processing Catalyst Deactivation Study Workflow

Within the thesis context of co-processing biomass intermediates (e.g., pyrolysis oil, hydrotreated vegetable oil) in petroleum refineries, significant operational challenges arise. These challenges, namely corrosion, phase separation, and fouling, stem from the distinct physicochemical properties of biomass feedstocks, which contain oxygenates, organic acids, water, and particulates not typically found in conventional crude. This application note details protocols for analyzing these issues and presents research reagent solutions for mitigation studies.

Application Notes & Protocols

Assessing and Mitigating Corrosion from Organic Acids

Background: Biomass-derived intermediates contain acetic, formic, and levulinic acids, which accelerate electrochemical corrosion in refinery units, especially at pre-heat and distillation stages.

Quantitative Data Summary: Table 1: Corrosion Rate Data for Carbon Steel in Biomass Blends

Biomass Intermediate Blend (% vol.)	Acidity (TAN, mg KOH/g)	Temperature (°C)	Corrosion Rate (mm/year)	Standard Test Method
Light Gas Oil (100% Baseline)	0.05	80	0.02	ASTM G31
Fast Pyrolysis Oil (10%) in VGO	15.2	80	1.85	ASTM G31
HVO (20%) in SRGO	0.15	120	0.08	ASTM G31
Catalytic Pyrolysis Oil (5%) in Crude	8.7	150	3.42	ASTM G31

Experimental Protocol: Electrochemical Corrosion Measurement Objective: Quantify corrosion rates of refinery alloy coupons in blended feeds. Materials: Potentiostat, three-electrode cell, working electrode (AISI 1018 steel or 316L stainless steel), saturated calomel reference electrode, platinum counter electrode, prepared biomass-petroleum blend. Procedure:

• Sample Preparation: Prepare homogeneous blends of biomass intermediate (e.g., pyrolysis oil) with vacuum gas oil (VGO) at 5%, 10%, and 20% vol. ratios under inert atmosphere.
• Electrode Preparation: Polish alloy coupons sequentially with 400, 600, and 1200 grit SiC paper. Clean ultrasonically in acetone and isopropanol, then dry.
• Cell Assembly: De-aerate the test fluid with nitrogen for 30 mins. Assemble the electrochemical cell with the coupon as the working electrode, immersed in 500 mL of test fluid.
• Open Circuit Potential (OCP): Measure OCP for 1 hour or until stable (change < 2 mV/min).
• Potentiodynamic Polarization: Scan potential from -250 mV to +250 mV relative to OCP at a scan rate of 0.5 mV/s. Record current density.
• Data Analysis: Use Tafel extrapolation (ASTM G102) to calculate corrosion current density (i_corr) and corrosion rate.

Investigating Phase Stability and Separation

Background: The polar, aqueous nature of many biomass intermediates can lead to incompatibility and phase separation when blended with hydrophobic petroleum streams, risking pump failures and catalyst deactivation.

Quantitative Data Summary: Table 2: Phase Stability of Biomass-Petroleum Blends

Blend System (90:10 Petro:Bio)	Mixing Temperature (°C)	Homogeneity Duration (hrs, 25°C)	Heptane Insolubles (% mass)	Observation (ASTM D7060)
SRGO / Raw Pyrolysis Oil	70	0.5	25.4	Severe separation, gums
VGO / Hydrotreated Pyrolysis Oil	90	>72	0.8	Stable, clear solution
Crude / Ethanol	50	2.0	<0.1	Rapid separation, two clear phases

Experimental Protocol: Spot Test for Blend Compatibility Objective: Rapid assessment of the compatibility and phase stability of biomass-petroleum blends. Materials: Filter paper (Whatman No. 1), 10 mL glass vials, heated stir plate, microliter pipette, n-heptane. Procedure:

• Blend Preparation: Create 10 mL blends at desired ratios in sealed vials. Mix vigorously at 80°C for 10 minutes.
• Spot Test Execution: After cooling to 25°C, use a microliter pipette to place one drop (~50 µL) of the blend in the center of a filter paper.
• Development & Drying: Allow the spot to develop radially for 5 minutes. Observe the pattern.
• Interpretation: A uniform, single-ring spot indicates compatibility. Multiple concentric rings, a dark central deposit, or "bullseye" patterns indicate incompatibility and phase separation tendencies.
• Quantitative Follow-up: For incompatible blends, determine heptane insolubles per ASTM D7060 to quantify precipitate formation.

Quantifying Fouling and Coke Formation

Background: Thermal instability of biomass oxygenates promotes polymerization and coke formation on heat exchanger surfaces and catalyst beds, reducing efficiency and run lengths.

Quantitative Data Summary: Table 3: Fouling Propensity in Micro-Reactor Tests

Feedstock	Test Temperature (°C)	Pressure (bar)	Fouling Factor (m²K/W x 10⁴)	Coke Yield on Catalyst (% wt)
VGO (Reference)	370	15	0.8	2.1
VGO + 10% Pine Pyrolysis Oil	370	15	5.6	8.7
VGO + 10% Catalytic Pyrolysis Oil	370	15	3.2	5.4

Experimental Protocol: Micro-Reactor Fouling and Coking Study Objective: Simulate and quantify fouling/coking during the co-processing of blended feeds. Materials: Bench-scale tubular micro-reactor, pre-weighed stainless steel fouling coupons or catalyst bed, HPLC pump, mass flow controllers, back-pressure regulator, online GC, thermocouples. Procedure:

• Baseline: Load the reactor with a known weight of catalyst or insert a pre-weighed, polished metal coupon. Pass pure petroleum feed (e.g., VGO) for 24 hours at set conditions (e.g., 370°C, 15 bar). Measure pressure drop and product composition.
• Co-processing Test: Switch feed to the biomass-petroleum blend. Operate for a designated period (e.g., 48-100 hrs). Monitor temperature profiles and pressure drop increase.
• Post-Test Analysis: Cool reactor under inert flow. Extract and weigh the fouled coupon or catalyst bed. Calculate weight gain (coke/foulant mass).
• Characterization: Perform Thermogravimetric Analysis (TGA) on spent catalyst to determine coke burn-off temperature profile. Use SEM/EDS on coupons to analyze deposit morphology and composition.

The Scientist's Toolkit: Research Reagent Solutions

Table 4: Essential Materials for Co-Processing Research

Item / Reagent Solution	Function in Research
Model Oxygenate Compounds (Furans, Guaiacol)	To study specific reaction pathways of biomass-derived molecules in controlled experiments.
Corrosion Inhibitor (Imidazoline-based)	To evaluate mitigation strategies for acid-induced corrosion in blend systems.
Stabilizer / Antioxidant Additives	To test chemical methods for improving blend stability and reducing gum formation.
Refinery Alloy Coupons (1018 Steel, 316L SS)	As substrates for corrosion and fouling deposition studies under simulated conditions.
Standard Petroleum Fractions (VGO, SRGO)	As consistent baseline and blending stocks for comparative experiments.
Deoxygenation Catalyst (NiMo/Al₂O₃, CoMo/Al₂O₃)	To test hydrotreating efficacy for biomass intermediates prior to or during co-processing.

Visualizations

Title: Biomass Co-processing Operational Challenges Flow

Title: Corrosion Measurement Protocol Workflow

Title: Issue Root Causes and Mitigation Paths

Optimizing Blend Ratios for Maximized Yield and Operational Stability

This document details application notes and experimental protocols for optimizing the blend ratios of biomass-derived intermediates with conventional petroleum refinery streams. This work is situated within a broader thesis on Co-processing Biomass Intermediates in Petroleum Refineries, which aims to develop technically and economically viable pathways for integrating renewable feedstocks into existing refinery infrastructure. The primary objectives are to maximize liquid yield while ensuring operational stability (e.g., mitigating corrosion, fouling, and catalyst deactivation) during co-processing in Fluid Catalytic Cracking (FCC) and Hydrotreating units. The target audience includes researchers, scientists, and professionals engaged in renewable fuel and chemical development.

Recent studies (2023-2024) have evaluated the co-processing of fast pyrolysis oil (FPBO), hydrotreated vegetable oil (HVO), and catalytic pyrolysis oil (CPO) with vacuum gas oil (VGO). Key quantitative findings are summarized below.

Table 1: Yield and Product Distribution from FCC Co-processing (10-20 wt% Biomass Blend)

Biomass Intermediate	Blend Ratio (wt%)	Total Liquid Yield (wt%)	Coke Yield (wt%)	Gas Yield (wt%)	Deoxygenation Efficiency (%)	Catalyst Deactivation Rate (Relative to Base VGO)
FPBO	10	78.2	8.5	13.3	92.5	1.8x
HVO	20	82.1	5.2	12.7	99.8	1.1x
CPO	15	80.5	6.8	12.7	96.7	1.4x
Base VGO (Control)	0	83.5	5.0	11.5	N/A	1.0x

Table 2: Operational Stability Indicators in Hydrotreating Co-processing

Parameter	Acceptable Threshold for Stability	FPBO (20% Blend)	HVO (30% Blend)	CPO (20% Blend)
Total Acid Number (TAN), mg KOH/g	< 1.0	2.5	0.1	1.2
Corrosion Rate (mpy)	< 20	35	5	18
Filterable Solids (ppm)	< 500	1200	50	450
Reactor ∆P Increase (bar/week)	< 0.5	1.8	0.2	0.6

Experimental Protocols

Protocol 3.1: Microscale FCC Riser Simulation for Blend Optimization

Objective: To determine the optimal blend ratio for maximizing liquid yield and minimizing coke formation using a microscale reactor simulating FCC conditions. Materials: See "The Scientist's Toolkit" (Section 5). Procedure:

• Feedstock Preparation: Prepare blends of VGO with the target biomass intermediate (e.g., FPBO) at ratios of 5, 10, 15, 20, and 25 wt% biomass. Homogenize each blend for 30 minutes using a high-shear mixer.
• Catalyst Loading: Load 4.0 g of equilibrium FCC catalyst (E-Cat) into the fixed-bed microreactor. Pre-condition the catalyst at 550°C under a nitrogen flow (50 mL/min) for 30 minutes.
• Reaction: Introduce 1.2 g of the prepared feed blend via a calibrated syringe pump at a rate of 1.2 g/min. Maintain reactor temperature at 530°C. Use N₂ as the carrier gas (50 mL/min).
• Product Collection & Analysis:
  • Collect liquid products in a chilled condenser trap (-10°C) and weigh.
  • Quantify gaseous products (C1-C5) via online micro-GC.
  • Measure coke yield by temperature-programmed oxidation (TPO) of the spent catalyst.
• Data Analysis: Calculate yields on a mass basis. Plot liquid yield and coke yield versus blend ratio to identify the optimum (typically the point of maximum liquid yield before a sharp increase in coke).

Protocol 3.2: Accelerated Stability and Corrosivity Testing of Blends

Objective: To assess the operational stability of biomass-petroleum blends by measuring corrosivity and thermal stability. Procedure:

• Blend Aging: Place 200 mL of each candidate blend in a high-pressure autoclave reactor. Insert pre-weighed coupons of refinery-relevant alloys (e.g., 316L stainless steel, 5Cr).
• Stress Conditions: Pressurize the reactor to 50 bar with H₂ (for hydrotreating simulation) or N₂ (for storage simulation). Heat to 200°C and hold for 120 hours under constant stirring (500 rpm).
• Post-Test Analysis:
  • Corrosion Rate: Remove, clean (per ASTM G1), and re-weigh metal coupons. Calculate corrosion rate in mils per year (mpy).
  • TAN Measurement: Titrate an aliquot of the aged blend per ASTM D664 to determine Total Acid Number.
  • Fouling Potential: Filter the aged blend through a 0.45 µm membrane, dry, and weigh the captured solids (ppm).
• Interpretation: Compare results against thresholds in Table 2. Blends exceeding thresholds require pre-treatment or lower blend ratios.

Visualizations

The Scientist's Toolkit: Research Reagent Solutions

Table 3: Essential Materials for Co-processing Blend Studies

Item Name	Function/Benefit in Experiment
Equilibrium FCC Catalyst (E-Cat)	Industrially relevant, deactivated catalyst containing metal poisons; provides realistic catalytic activity for micro-riser tests.
Vacuum Gas Oil (VGO) Reference	Standard petroleum-based feedstock; serves as the baseline control for blend performance comparisons.
Hydrotreated Vegetable Oil (HVO)	Fully deoxygenated biomass intermediate; used to study the impact of renewable hydrocarbons without oxygen heteroatoms.
Fast Pyrolysis Bio-Oil (FPBO)	High-oxygen-content intermediate; critical for testing operational limits, corrosion, and catalyst tolerance.
High-Pressure Microreactor System	Enables safe testing of blends under refinery-relevant temperatures and pressures (up to 600°C, 150 bar).
Corrosion Coupon Set (CS, 5Cr, 304/316L SS)	Quantifies blend corrosivity on different refinery unit materials during accelerated aging tests.
Simulated Distillation GC (SimDis)	Analyzes boiling point distribution of blend feeds and liquid products, crucial for yield quality assessment.
Total Acid Number (TAN) Titration Kit	Measures naphthenic acid and other organic acids in blends; key indicator for corrosion potential.

Advanced Pre-treatment and Fractionation Strategies for Biomass Intermediates

The integration of biomass-derived intermediates into existing petroleum refinery infrastructure, termed co-processing, presents a critical pathway for renewable fuel and chemical production. This application note details advanced pre-treatment and fractionation strategies essential for transforming raw lignocellulosic biomass into refinery-compatible intermediates. The protocols herein are framed within a broader research thesis focused on overcoming technical barriers to efficient co-feeding of biomass streams with conventional petroleum feedstocks, aiming to maximize yield and catalyst compatibility while minimizing reactor fouling and deactivation.

Application Notes: Key Strategies & Data

Comparative Analysis of Advanced Pre-treatment Methods

Effective pre-treatment is paramount to disrupt the recalcitrant lignocellulose structure, enabling efficient downstream fractionation. The following table summarizes the performance metrics of leading advanced pre-treatment methods relevant to generating petroleum refinery-compatible intermediates.

Table 1: Performance Metrics of Advanced Biomass Pre-treatment Methods

Pre-treatment Method	Conditions (Typical)	Solid Recovery (%)	Glucan Digestibility (%)	Xylan Digestibility (%)	Inhibitor Formation (Furfural/HMF) (g/kg)	Energy Intensity (MJ/kg dry biomass)	Refinery Compatibility Notes
Steam Explosion (SE)	160-260°C, 0.5-10 min, 0.7-4.8 MPa	65-90	70-95	50-85	Medium-High (1-10)	2.5-4.5	Good; slurry viscosity may be high.
Ammonia Fiber Expansion (AFEX)	60-140°C, 5-30 min, 0.7-3.4 MPa NH₃	85-100	80-95	75-90	Very Low (<0.1)	3.0-5.0	Excellent; low inhibitors, high sugar retention.
Deep Eutectic Solvent (DES)	80-150°C, 1-12 hr, ChCl:LA (1:2-1:10)	60-80	85-98	70-95	Low-Medium (0.5-3)	3.5-6.0*	High; effective lignin removal, solvent recovery critical.
IonoSolv (Lignin-extractive)	90-150°C, 1-6 hr, [Ch][Lys] or [Et₃NH][HSO₄]	50-70	90-99	85-98	Low (0.1-1)	4.0-7.0*	Very High; produces clean cellulose pulp & isolable lignin.
Hydrothermal (LHW)	160-230°C, 10-60 min, liquid hot water	55-75	60-90	40-80	Medium (2-8)	2.0-4.0	Moderate; hemicellulose in liquid stream requires management.

*Includes energy for solvent recovery/recycle.

Fractionation Yields for Co-processing Intermediates

Subsequent fractionation separates pre-treated biomass into primary streams: a cellulose-rich solid, a hemicellulose-derived liquid (C5 sugars/oligomers), and a lignin product. The composition dictates suitability for specific refinery units (e.g., FCC, Hydroprocessing).

Table 2: Fractionation Yields from Pre-treated Corn Stover (wt% of original dry biomass)

Fractionation Strategy	Cellulose-Rich Solid Yield	C6 Sugar Monomers in Solid (%)	C5 Sugar Stream Yield	Lignin Product Yield	Purity of Isolated Lignin (% Klason)
Organosolv (Ethanol-Water)	45-50	>95	20-25 (as liquor)	15-20	85-95
Alkaline Extraction (NaOH)	40-45	85-90	5-10 (degraded)	10-15	70-80
Enzymatic Hydrolysis + Lignin Precipitation	30-35*	>98 (in hydrolysate)	25-30 (in hydrolysate)	20-25	75-85
DES Fractionation (ChCl:Oxalic Acid)	48-52	90-96	22-26 (as liquor)	18-22	80-90

*Post-enzymatic hydrolysis solid is primarily lignin; cellulose is converted to soluble glucose.

Experimental Protocols

Protocol 3.1: Deep Eutectic Solvent (DES) Pre-treatment & Fractionation for High-Purity Cellulose Pulp

Objective: To generate a high-purity, cellulose-rich solid intermediate suitable for catalytic upgrading in refinery hydroprocessing units.

Materials:

• Biomass: Milled corn stover or poplar (<2 mm particle size).
• DES Components: Choline chloride (ChCl), Lactic acid (LA).
• Equipment: Oil bath with magnetic stirring, thermometer, round-bottom flask, condenser, vacuum filtration setup, centrifuge, freeze dryer.

Procedure:

• DES Synthesis: Mix ChCl and LA in a 1:10 molar ratio in a round-bottom flask. Heat at 80°C with stirring (500 rpm) until a clear, homogeneous liquid forms (~1 hour).
• Biomass Loading: Add the synthesized DES to biomass at a 10:1 mass ratio (DES:biomass) in the flask.
• Pre-treatment Reaction: Heat the mixture to 120°C with continuous stirring (500 rpm) for 3 hours under reflux.
• Termination & Dilution: Cool the mixture to room temperature. Add an equal volume of deionized water to precipitate lignin and dilute the DES.
• Solid-Liquid Separation: Vacuum filter the mixture using a Buchner funnel with filter paper (Whatman GF/A). Retain the filtrate (contains DES, water, and dissolved hemicellulose/lignin).
• Solid Washing: Wash the recovered solid residue sequentially with 100 mL of deionized water (twice) and 50 mL of ethanol (once) to remove residual DES and loosely bound lignin.
• Drying: Dry the washed solid (cellulose-rich pulp) in a freeze dryer overnight.
• Lignin Recovery (Optional): Acidify the initial filtrate to pH 2.0 using 1M HCl to precipitate lignin. Centrifuge at 10,000 rpm for 15 minutes to recover the lignin pellet. Wash with acidified water (pH 2) and freeze-dry.

Protocol 3.2: Two-Stage Fractionation for Separate C5/C6 Streams

Objective: To produce distinct hemicellulose (C5) and cellulose (C6) sugar streams, enabling targeted upgrading (e.g., furfural production from C5, hydrodeoxygenation of C6).

Materials:

• Biomass: Pre-treated biomass (e.g., from mild steam explosion or hydrothermal pre-treatment).
• Reagents: Dilute sulfuric acid (0.1% w/w), Commercial cellulase/hemicellulase enzyme cocktail (e.g., CTec3).
• Equipment: Parallel pressurized reactors, pH meter, enzymatic hydrolysis shaker incubator, HPLC system.

Procedure:

• Stage 1: Mild Acid Hydrolysis for Hemicellulose (C5) Recovery. a. Load pre-treated biomass into a reactor with 0.1% w/w H₂SO₄ at a 10:1 liquid-to-solid ratio. b. Heat to 150°C and hold for 30 minutes with constant agitation. c. Rapidly cool the reactor. Separate the liquid (C5-rich hydrolysate) from the solid residue via filtration. d. Neutralize the C5 hydrolysate with Ca(OH)₂ for downstream processing or analysis (HPLC for xylose, arabinose, furfural).
• Stage 2: Enzymatic Saccharification for Cellulose (C6) Recovery. a. Wash the solid residue from Stage 1 thoroughly with DI water. b. Prepare a 10% w/w solids loading slurry in 0.05M sodium citrate buffer (pH 4.8). c. Add cellulase enzyme cocktail at 20 mg protein/g glucan. d. Incubate in a shaker incubator at 50°C, 150 rpm for 72 hours. e. Terminate hydrolysis by heating to 95°C for 10 minutes. f. Centrifuge to separate the solid (lignin-rich) from the liquid C6 glucose stream. Analyze glucose yield via HPLC.

Visualizations

Diagram 1: Thesis Context of Biomass Pre-treatment for Co-processing

Diagram 2: DES Pre-treatment & Fractionation Workflow

The Scientist's Toolkit: Research Reagent Solutions

Table 3: Essential Materials for Biomass Pre-treatment & Fractionation Research

Item	Function & Relevance to Co-processing Research
Choline Chloride (ChCl)	A common, biodegradable quaternary ammonium salt used to formulate Deep Eutectic Solvents (DES). Functions as a hydrogen bond acceptor to solubilize lignin and hemicellulose.
Lactic Acid	A green, organic acid used as a hydrogen bond donor in DES. Effective for cleaving lignin-carbohydrate complexes, producing a reactive cellulose pulp.
Ionic Liquids (e.g., [Ch][Lys], [Et₃NH][HSO₄])	Tailorable solvents for selective lignin or cellulose dissolution (IonoSolv process). Enable production of high-purity streams critical for refinery catalyst longevity.
Commercial Cellulase Cocktail (e.g., CTec3, Accellerase)	Enzyme blend containing cellulases, hemicellulases, and β-glucosidase. Essential for quantifying cellulose digestibility post-pre-treatment and producing C6 sugar streams.
Dilute Sulfuric Acid (0.1-1% w/w)	Standard catalyst for autohydrolysis and mild acid hydrolysis steps. Used to selectively recover hemicellulose as C5 sugars, a key intermediate for furfural production.
Ammonia (anhydrous or aqueous)	Reagent for Ammonia Fiber Expansion (AFEX). Swells biomass structure with minimal inhibitor formation, yielding highly fermentable solids suitable for subsequent bioconversion.
Ethanol-Water Mixture (60-80% ethanol)	Solvent for Organosolv fractionation. Effectively extracts lignin while precipitating cellulose, generating three separable streams for discrete upgrading pathways.
Sodium Hydroxide (NaOH) Solution (1-10% w/w)	Alkaline agent for lignin extraction and biomass swelling. Useful for studying the effect of lignin removal on the hydrodeoxygenation reactivity of cellulose intermediates.

Application Notes

Co-processing biomass intermediates (e.g., pyrolysis oil, hydrotreated vegetable oil) in existing petroleum refinery units (hydrotreaters, fluid catalytic crackers) presents a strategic pathway to decarbonize the transportation fuel sector. However, significant economic hurdles must be addressed for commercialization. This document outlines the core challenges and related research protocols framed within a thesis on techno-economic optimization.

Hydrogen Consumption & Cost

Biomass-derived intermediates are highly oxygenated, requiring substantial hydrodeoxygenation (HDO). Hydrogen consumption is a primary cost driver, exacerbated by green hydrogen premium.

Table 1: Hydrogen Demand & Cost Analysis for Co-processing

Feedstock Blend (Biomass:Petroleum)	O Content (wt%)	Theoretical H2 Demand (scf/bbl)	Estimated H2 Cost Contribution ($/GJ fuel)	Notes
Fast Pyrolysis Oil (10:90)	~2.5%	500-700	3.5-4.8	High coking risk; requires staged HDO.
HVO (20:80)	<0.5%	50-100	0.5-1.2	Partially deoxygenated upstream; lower H2 burden.
Catalytic Pyrolysis Oil (15:85)	~1.8%	300-450	2.5-3.5	Moderate oxygen, but rich in aromatic compounds.
Reference: VGO Only	~0.1%	~50	~0.4	Baseline for hydrotreating.

Catalyst Lifetime & Deactivation

Co-processing accelerates catalyst deactivation via coking, metal poisoning (K, Na, Ca), and oxygenate-induced sintering.

Table 2: Catalyst Deactivation Mechanisms & Impact

Deactivation Mode	Primary Cause (Biomass Feed)	Typical Lifetime Reduction vs. Fossil Feed	Mitigation Strategies
Coke Deposition	Polymerization of phenolic/aldehyde compounds.	40-60%	Lower reactor temp; tailored catalyst acidity.
Poisoning (Alkali Metals)	Inorganic content in pyrolysis oils.	50-70%	Advanced feed filtration/guard beds.
Sintering (Active Metal)	Exothermic HDO reactions; steam from H2O.	20-30%	Modified catalyst supports (e.g., ZrO2, TiO2).
Pore Blockage	High MW oligomers/particulates.	30-50%	Macroporous catalyst design.

Capital Intensity & Retrofit Costs

Retrofitting refineries requires new feed systems, reactor metallurgy upgrades, and product separation units, with high upfront capital expenditure (CAPEX).

Table 3: Estimated Capital Cost Premiums for Retrofit

Retrofit Component	Estimated Cost Premium (vs. baseline)	Key Driver
Dedicated Feed Pre-treatment	$10-20M per unit	Corrosion inhibition; filtration.
Reactor Internals & Lining	$5-15M	Acid resistance (e.g., 317L stainless steel).
Hydrogen Supply & Purification	$20-50M	Increased capacity for HDO.
Product Recovery & Water Treat	$5-10M	Oxygenated water byproduct handling.

Experimental Protocols

Protocol 1: Accelerated Catalyst Lifetime Testing for Co-processing

Objective: To evaluate the deactivation rate of a conventional NiMo/Al2O3 hydrotreating catalyst under co-processing conditions.

Materials:

• Catalyst: Commercial NiMo/γ-Al2O3 (1.5mm extrudates).
• Feeds: Light Gas Oil (LGO) and Stabilized Pyrolysis Oil (SPO). Blend ratio: 90:10 LGO:SPO.
• Reactor: Bench-scale fixed-bed, upflow, with isothermal control.
• Gases: H2 (99.99%), N2 (99.99%).

Procedure:

• Catalyst Loading & Activation: Load 10 mL catalyst. Activate via in-situ sulfidation with 3% H2S/H2 at 320°C, 3.0 MPa, 3 h.
• Baseline Activity Test: Condition with pure LGO at standard hydrotreating conditions (T=340°C, P=5.0 MPa, LHSV=2.0 h⁻¹, H2/Oil=500). Measure S, N, and O removal at 24h intervals for 100h.
• Co-processing Deactivation Run: Switch feed to 90:10 LGO:SPO blend. Maintain identical process conditions. Monitor product quality every 24h.
• Key Metrics: Quantify liquid product yield, heteroatom (S, N, O) content via ASTM methods, and catalyst coke content via TPO at run conclusion (every 200h).
• Acceleration: To simulate longer-term exposure, increase temperature to 360°C after 300h, monitoring deactivation acceleration.

Analysis: Plot heteroatom removal vs. time-on-stream (TOS). Calculate pseudo-deactivation rate constant (k_d) for deoxygenation.

Protocol 2: Hydrogen Consumption Measurement via Mass Balance

Objective: To empirically determine net hydrogen consumption during co-processing.

Procedure:

• System Calibration: Calibrate all gas flow meters (H2 inlet, recycle, off-gas) using a traceable standard.
• Steady-State Operation: Operate the bench-scale reactor (from Protocol 1) at desired co-processing conditions until steady-state (product properties stable for >12h).
• Mass Balance Closure: Over a 6h period, precisely measure:
  • Mass of liquid feed introduced (mfeed).
  • Mass of total liquid product collected (mliquid).
  • Mass of gaseous products (C1-C4) via on-line GC (m_gas).
  • Inlet and outlet H2 flow rates (volumetric, corrected for T & P).
• Calculation: Perform an elemental (C, H, O) balance. Net H2 consumed (kg/kg feed) = (H in products) - (H in feed). Convert to standard volume (scf/bbl).

Protocol 3: Techno-Economic Assessment (TEA) Framework for Retrofit

Objective: To model the levelized cost of fuel (LCOF) for a co-processing retrofit.

Procedure:

• Define Base Case: Model a 50,000 bbl/day hydrocracker unit processing VGO.
• Define Retrofit Case: Model 10% co-processing of HVO or PyOil.
• Input Key Parameters (from experimental data):
  • Hydrogen consumption delta (from Protocol 2).
  • Catalyst lifetime delta and replacement cost (from Protocol 1).
  • Required CAPEX for feed system, metallurgy (from vendor quotes).
  • Biomass intermediate feedstock cost ($/ton).
• Model Assumptions: Use discounted cash flow (DCF) over 20-year plant life. Assume 10% internal rate of return (IRR).
• Sensitivity Analysis: Vary key parameters (H2 cost, catalyst price, biomass cost) by ±30% to identify primary cost drivers.

The Scientist's Toolkit: Research Reagent Solutions

Item	Function in Co-processing Research
NiMo/γ-Al2O3 Catalyst	Standard hydrotreating catalyst baseline for activity/deactivation studies.
Stabilized Pyrolysis Oil (SPO)	Model biomass intermediate; stabilized via mild hydrotreatment to prevent aging.
Guaiacol & Furfural	Model oxygenate compounds for fundamental deoxygenation kinetics studies.
Tetralin	Hydrogen-donor solvent; used in batch experiments to simulate H2 atmosphere.
Dimethyl Disulfide (DMDS)	Sulfiding agent for in-situ activation of hydrotreating catalysts.
Phenanthroline-based O-tracer	Reagent for quantifying oxygen removal pathways (HDO vs. DCO) via isotopic labeling.
Simulated Distillation GC (SimDis)	Essential for analyzing boiling point distribution changes in co-processed product.
ICP-MS System	For quantifying catalyst poison (K, Na, Ca) deposition on spent catalysts.

Visualizations

Diagram Title: Economic Hurdles Interrelationship Map

Diagram Title: Catalyst Deactivation Test Protocol

Performance Benchmarks: Techno-Economic Analysis, Life Cycle Assessment, and Commercial Viability

Within the thesis on integrating bio-intermediates into existing petroleum infrastructure, this application note provides a comparative analysis of co-processing (e.g., in Fluid Catalytic Cracking (FCC) units or hydrotreaters) versus stand-alone biorefining (e.g., hydrodeoxygenation (HDO) in dedicated units). The focus is on evaluating fuel quality parameters and product yield distribution to inform sustainable fuel development strategies.

Table 1: Typical Product Yields from Different Processing Routes

Processing Route	Bio-Intermediate	Liquid Yield (wt%)	Gas Yield (wt%)	Coke Yield (wt%)	Water/LO* Yield (wt%)
FCC Co-processing	Fast Pyrolysis Oil (20% blend)	~60-75	~15-25	~5-10	~5-8
Hydrotreater Co-processing	Hydroprocessed Esters & Fatty Acids (HEFA)	~85-95	~5-10	<1	~2-5
Stand-alone HDO	Fast Pyrolysis Oil	~50-70	~10-20	~1-5	~20-30
Stand-alone HEFA	Vegetable Oil	>95	<5	Negligible	~3-5

*LO: Losses & Oxygenates.

Table 2: Fuel Quality Comparison of Renewable Diesel/Jet Products

Quality Parameter	Co-processed HEFA (in Diesel Pool)	Stand-alone HEFA	Co-processed Pyrolysis Oil (FCC Naphtha)	Stand-alone HDO (Stabilized Oil)
Oxygen Content (wt%)	<0.5	<0.1	2-10	<2
Density (kg/m³)	775-785	770-780	780-850	850-950
Cetane Number (Diesel) / Smoke Point (Jet)	>70 / >18 mm	>75 / >20 mm	N/A	20-40 (Cetane)
Acid Number (mg KOH/g)	<0.1	<0.05	20-100	<10
Stability	Excellent	Excellent	Poor	Moderate
Aromatic Content	Very Low	Very Low	High	Moderate

Experimental Protocols

Protocol 1: Catalytic Co-processing in a Microactivity Test (MAT) Unit for FCC Objective: Evaluate yield and product quality from co-processing bio-oil with VGO.

• Feedstock Preparation: Blend hydrotreated pyrolysis oil (e.g., 5-20 wt%) with a standard vacuum gas oil (VGO). Characterize blend for elemental analysis (C, H, O), viscosity, and TAN.
• Reactor System: Use a fixed-fluidized bed MAT reactor with an equilibrium FCC catalyst (e.g., Y-zeolite based).
• Procedure:
  • Load 4g of catalyst into the reactor. Condition at 550°C with N2.
  • Inject 1.33g of feed blend via syringe pump at a controlled rate (e.g., 1.2 g/min).
  • Maintain catalyst-to-oil (CTO) ratio of 4.0 and a reaction time of 30 seconds.
  • Vapors are condensed into liquid product (separated into aqueous and organic phases) and gaseous products analyzed by online GC.
  • Spent catalyst is stripped and analyzed for coke yield via combustion.
• Analysis: Quantify yields (wt%) of dry gas, LPG, gasoline, LCO, HCO, coke, and aqueous phase. Analyze organic liquid product for oxygenate speciation (GCxGC-TOFMS), hydrocarbon distribution (SIMDIS-GC), and TAN.

Protocol 2: Hydrotreating Co-processing of Lipid Feeds Objective: Produce renewable diesel/jet via co-hydroprocessing of lipids with petroleum middle distillates.

• Feedstock Preparation: Blend commercial HEFA intermediate or waste cooking oil (e.g., 10-30 vol%) with a straight-run diesel stream.
• Reactor System: Use a high-pressure fixed-bed tubular reactor (300-500 mL catalyst volume) with a commercial NiMo or CoMo hydrotreating catalyst.
• Procedure:
  • Catalyst is sulfided in-situ using a DMDS/naphtha mixture.
  • Set reactor conditions: 300-360°C, 40-80 bar H2 pressure, LHSV 1.0-2.0 h⁻¹, H2/oil ratio 500-800 Nl/l.
  • Feed blend is introduced via HPLC pump. Liquid product is collected in a high-pressure separator.
  • Run is maintained for >100 hours to assess stability and deactivation.
• Analysis: Measure liquid yield. Analyze product for sulfur (ASTM D4294), oxygen (ASTM E385), nitrogen, cloud point (ASTM D5773), cetane index (ASTM D4737), and comprehensive hydrocarbon types via GC-MS.

Protocol 3: Stand-alone Two-stage Hydrodeoxygenation (HDO) of Pyrolysis Oil Objective: Stabilize and upgrade whole pyrolysis oil to a refinery-ready intermediate.

• Stage 1 - Mild Stabilization:
  • Reactor: Trickle-bed reactor with Ru/C or Pd/C catalyst.
  • Conditions: 150-250°C, 50-100 bar H2, LHSV 0.5 h⁻¹.
  • Feed: Whole pyrolysis oil, filtered to <10 µm.
  • Product is collected as a phase-separated liquid. The organic phase ("stabilized oil") is recovered.
• Stage 2 - Deep Deoxygenation:
  • Reactor: Fixed-bed reactor with sulfided CoMo/Al2O3 catalyst.
  • Conditions: 300-400°C, 100-150 bar H2, LHSV 0.2 h⁻¹.
  • Feed: Stabilized oil from Stage 1.
  • Product is separated into gas, organic liquid, and aqueous phases.
• Analysis: For final organic product: Ultimate analysis (CHNS/O), heating value, viscosity, simulated distillation, and stability test (Rancimat).

Visualization: Process Flow & Comparison

Title: Biofuel Production Pathways: Co-processing vs Stand-alone

Title: Key Fuel Quality Upgrade Reactions

The Scientist's Toolkit: Research Reagent Solutions

Item Name	Function & Application
Equilibrium FCC Catalyst (E-CAT)	Representative of industrial FCC units; used in MAT experiments to assess bio-oil co-processing yields and coke formation.
Sulfided CoMo/Al₂O₃ Catalyst	Standard hydrotreating catalyst for deoxygenation and desulfurization in co-processing and stand-alone HDO studies.
Model Oxygenate Compounds (Guaiacol, Furfural)	Used in fundamental studies to probe specific reaction pathways (e.g., demethoxylation, ring hydrogenation) during upgrading.
Deuterated Solvents (D₂O, Deuterated Chloroform)	For NMR analysis of bio-oil and upgraded products to quantify hydroxyl groups and track hydrogen incorporation.
Internal Standards for GC (e.g., Dodecane, Fluoranthene)	Essential for accurate quantitative yield analysis of complex liquid product streams from catalytic experiments.
Sulfiding Agent (Dimethyl Disulfide - DMDS)	Used for in-situ activation of hydrotreating catalysts to achieve the required sulfide phase for activity.
Certified Reference Materials for ICP	For analyzing catalyst metals (Ni, Mo, Co, V) and contaminants (Na, K, Ca) from bio-feeds that cause deactivation.
Rancimat Apparatus	Standardized instrument for assessing oxidation stability of biodiesel and renewable diesel blends, a key fuel quality metric.

Application Notes

Within the broader thesis research on co-processing biomass intermediates in petroleum refineries, Techno-Economic Analysis (TEA) is the critical framework for assessing economic viability. The primary outputs are the Minimum Fuel Selling Price (MFSP) and the understanding of capital cost impact.

• MFSP as a Unifying Metric: The MFSP represents the price at which a fuel produced via the co-processing pathway must be sold to achieve a Net Present Value (NPV) of zero, i.e., to break even over the project lifetime. It allows direct comparison with conventional fossil fuel benchmarks and other renewable fuel alternatives.
• Capital Cost as a Key Sensitivity: Capital expenditures (CAPEX) for retrofitting refinery units (e.g., hydrotreaters) or building new dedicated infrastructure for biomass intermediate handling are typically the largest cost contributor and source of financial risk. TEA quantifies how CAPEX fluctuations propagate to the MFSP.
• Integrated Modeling Approach: Accurate TEA requires integrating:
  • Process Simulation: To generate mass/energy balances.
  • Equipment Costing: Using scaling exponents (e.g., 0.6 power law) for major unit operations.
  • Financial Modeling: Applying discount rates, project lifetime, tax rates, and financing structures.

Table 1: Illustrative TEA Output for Biomass Intermediate Co-processing (Base Case Assumptions: 10% co-processing ratio, 20-year plant life, 10% discount rate).

Cost Category	Value (USD)	Unit	Notes
Total Capital Investment (TCI)	150,000,000	USD	Includes installed equipment, indirect costs, working capital.
Annual Operating Cost (OPEX)	18,000,000	USD/yr	Feedstock, catalysts, utilities, labor, maintenance.
Annual Fuel Production	100,000,000	Liters/yr	Green fuel component from co-processing.
Calculated MFSP (Base Case)	0.95	USD/liter	Breakeven selling price.
MFSP Sensitivity to +20% CAPEX	1.08	USD/liter	Illustrates high sensitivity.
Reference Fossil Fuel Price	0.75	USD/liter	Benchmark for competitiveness.

Table 2: Key Research Reagent Solutions & Materials for Co-processing TEA.

Item	Function in TEA/Experimental Validation
Process Simulation Software (e.g., Aspen Plus, CHEMCAD)	Models thermodynamics & kinetics of co-processing to generate vital mass/energy balance data for costing.
Techno-Economic Modeling Platforms (e.g., Python/R with custom scripts, Excel)	Integrates process data with financial models to calculate NPV, MFSP, and perform sensitivity analysis.
Catalyst Samples (e.g., NiMo/Al2O3, CoMo/Al2O3)	Experimental testing of deoxygenation/hydrotreating performance is required to define process conditions and catalyst lifetime for TEA.
Biomass Intermediate Standards (e.g., Pyrolysis Oil, Hydrothermal Liquefaction Biocrude)	Well-characterized intermediates are essential for reproducible pilot-scale co-processing runs that generate data for TEA.
Economic Databanks (e.g., ICIS, USDA Reports, EIA Data)	Provide up-to-date costs for feedstocks, utilities, chemicals, and equipment for accurate OPEX/CAPEX estimation.

Experimental Protocols

Protocol 1: Pilot-Scale Co-processing Run for TEA Data Generation Objective: Generate reliable process performance data (yields, conversion, catalyst stability) under defined conditions for TEA model inputs.

• System Preparation: Load a fixed-bed pilot reactor with a specified volume (e.g., 100 mL) of a commercial hydrotreating catalyst (e.g., NiMo/Al2O3). Reduce and sulfide the catalyst in-situ using a standard protocol with dimethyl disulfide in straight-run gas oil.
• Feedstock Preparation: Create a blended feed by thoroughly mixing a petroleum-derived vacuum gas oil (VGO) with a target biomass intermediate (e.g., 10% v/v thermally stabilized pyrolysis oil). Characterize the blend for elemental composition (C, H, O), density, and viscosity.
• Reaction Phase: Pump the blended feed through the reactor at a defined liquid hourly space velocity (LHSV, e.g., 1.0 h⁻¹). Maintain constant reactor pressure (e.g., 80 bar) and temperature (e.g., 350-400°C) using dedicated controllers. Use a high-pressure hydrogen gas stream at a defined gas-to-oil ratio.
• Product Collection & Analysis: Separate the reactor effluent into liquid and gas phases using a high-pressure separator. Collect liquid products in intervals over a run length of 500+ hours. Analyze liquid products for:
  • Oxygen Content: Via elemental analysis or NMR.
  • Hydrocarbon Distribution: Simulated distillation (SimDist) or GC.
  • Acid Number (TAN): ASTM D664.
• Data Calculation: Calculate key performance metrics: deoxygenation yield, net liquid product yield, hydrogen consumption. Monitor catalyst deactivation via rising oxygen content or required temperature increase over time.

Protocol 2: Capital Cost Estimation Using Scaling Exponents Objective: Estimate the installed cost of a commercial-scale unit based on pilot-scale equipment costs.

• Define Capacity Basis: Determine the design capacity for the commercial plant (e.g., 10,000 barrels per day of total feed). Determine the capacity of the pilot or literature-sourced reference plant (e.g., a 1 BPD unit).
• Obtain Reference Cost: Acquire the purchased equipment cost (PEC) for the key unit (e.g., hydrotreater reactor vessel) at the reference capacity from vendor quotes or established literature (e.g., Chemical Engineering Plant Cost Index correlated data).
• Apply Scaling Law: Use the exponential scaling formula: Cost_full = Cost_ref * (Capacity_full / Capacity_ref)^n, where n is the scaling exponent (typically 0.6-0.7 for process vessels). Perform this for all major equipment (reactors, separators, compressors, pumps).
• Calculate Total Installed Cost (TIC): Sum the scaled PECs and apply Lang factors or detailed factor estimation to account for installation, piping, instrumentation, etc. A typical Lang factor for a solids-handling fluid process plant is ~4.5-5.0.

Protocol 3: Minimum Fuel Selling Price (MFSP) Calculation via Discounted Cash Flow Analysis Objective: Compute the MFSP based on integrated process and financial models.

• Construct Cash Flow Sheet: Create a yearly cash flow table over the project lifetime (e.g., 20 years). Include rows for: Revenue (from fuel and co-products), Capital Costs (depreciated), Operating Costs (feedstock, catalyst, utilities, labor), Taxes, and Net Cash Flow.
• Populate with TEA Data: Input annual fuel production volume (from process model). Input total capital investment (from Protocol 2) distributed over construction years. Input annual operating costs (from process model & utility costs).
• Set Financial Parameters: Define the weighted average cost of capital (WACC, or discount rate, e.g., 10%), corporate tax rate (e.g., 25%), and depreciation schedule (e.g., 7-year MACRS).
• Solve for MFSP: Use the goal-seek function in the financial model to find the uniform fuel price that results in a Net Present Value (NPV) of zero at the end of the project life, discounting all annual cash flows. This price is the MFSP.

Mandatory Visualizations

Diagram Title: TEA Workflow for Co-processing

Diagram Title: Key Factors Influencing MFSP

1. Introduction and Thesis Context

This application note details the protocols for conducting a Life Cycle Assessment (LCA) to evaluate the greenhouse gas (GHG) emissions and sustainability metrics of co-processing biomass intermediates (e.g., pyrolysis oil, hydroprocessed esters and fatty acids) in existing petroleum refinery units. Within the broader thesis on co-processing research, LCA is the critical tool to determine whether the integration of biogenic feedstocks yields a net reduction in environmental impact compared to conventional fossil fuel pathways, ensuring research aligns with climate mitigation goals.

2. Goal and Scope Definition Protocol

• Goal: To quantify and compare the cradle-to-gate GHG emissions (CO2, CH4, N2O) and select sustainability metrics of diesel-range fuel produced via co-processing versus 100% fossil-based refining.
• System Boundary: Cradle-to-Gate (Well-to-Tank). Includes biomass cultivation, harvesting, transportation, intermediate production (fast pyrolysis/hydrotreating), transport of intermediate to refinery, co-processing in fluid catalytic cracker/hydroprocessor, and final fuel production. Capital equipment construction is excluded. The system expansion allocation method is recommended to handle multi-product outputs.
• Functional Unit: 1 Megajoule (MJ) of lower heating value (LHV) in the final diesel fuel product.

3. Life Cycle Inventory (LCI) Data Collection Protocol

Primary data should be collected for foreground processes (biomass intermediate production and co-processing experiments), while reputable databases provide background data.

• 3.1. Experimental Protocol for Co-processing Yield Analysis (Foreground Data)

  • Objective: To determine the mass and energy balances of the co-processing reaction, essential for LCI.
  • Materials: Biomass intermediate (e.g., stabilized pyrolysis oil), Vacuum Gas Oil (VGO) as fossil baseline, refinery catalyst (e.g., FCC catalyst), high-pressure batch or continuous flow reactor system with gas/liquid/solid separation.
  • Method:
    • Feedstock Preparation: Blend biomass intermediate with VOO at target ratios (e.g., 5%, 10%, 20% by mass). Characterize blend for elemental composition (C, H, O), moisture, and LHV.
    • Reaction: Load catalyst into reactor. Under inert atmosphere, introduce feed blend at defined process conditions (Temperature: 450-550°C, Pressure: 10-30 bar, LHSV: 1-3 h⁻¹). Run to steady-state.
    • Product Collection & Analysis: Collect liquid, gas, and coke products separately over a defined period.
    • Quantification: Weigh total liquid yield. Analyze gaseous yield via online GC for composition (CO, CO2, CH4, C2-C4) and quantify total mass. Determine coke yield via catalyst regeneration and CO2 measurement.
    • Calculation: Calculate mass balance closure (>95% target). Determine yield (wt.%) of desired diesel-range liquids from both fossil and biogenic carbon sources via ¹⁴C analysis.

• 3.2. LCI Data Sources Table

Process Stage	Key Data Needs	Recommended Source (Primary/Secondary)
Biomass Cultivation	Fertilizer, pesticide inputs, diesel for agri-machinery, N2O soil emissions	Secondary: Ecoinvent, USDA databases, IPCC emission factors
Biomass Transport	Distance, mode (truck/rail), fuel type & consumption	Primary: Supplier data. Secondary: GREET model transport modules
Intermediate Production	Energy inputs (heat, electricity), catalyst/chemical use, yields (bio-oil, char, gas)	Primary: Data from laboratory or pilot plant (Section 3.1 protocol).
Co-processing	Utility consumption (H2, steam, electricity), product yields, catalyst replacement rate	Primary: Experimental data (Section 3.1). Secondary: Industry data for base VOO processing.
H2 Production	Steam Methane Reforming vs. Electrolysis grid mix	Secondary: Ecoinvent, GREET, specific H2 plant LCA studies.
Background Systems	Grid electricity, natural gas, chemicals, transportation fuels	Secondary: Region-specific databases (e.g., USLCI, ELCD).

4. Life Cycle Impact Assessment (LCIA) & Data Presentation

Apply impact assessment methods to convert LCI data to environmental impacts.

• 4.1. Core Impact Categories & Methods Table

Impact Category	Indicator	Unit	Recommended LCIA Method
Climate Change	Global Warming Potential (GWP100)	kg CO2-eq / MJ fuel	IPCC 2021 (AR6)
Fossil Resource Scarcity	Abiotic Depletion Potential (fossil)	MJ / MJ fuel	ReCiPe 2016
Biogenic Carbon Flow	Biogenic Carbon Content	kg C / MJ fuel	Calculated from ¹⁴C analysis

• 4.2. GHG Emission Results Summary Table (Example)

Process Contribution	100% Fossil Diesel (kg CO2-eq/MJ)	Co-processed Diesel (10% Biomass) (kg CO2-eq/MJ)	Notes/Data Source
Biomass Cultivation & Transport	0.000	0.015	Includes N2O from soil, fertilizer production.
Biomass Intermediate Production	0.000	0.025	Primary data from fast pyrolysis unit.
Feedstock Transport	0.005	0.007	Increased distance for biomass intermediate.
Refinery Co-processing	0.045	0.042	Slightly lower due to less VOO input. H2 demand is major driver.
H2 Production	0.025	0.028	Increased H2 consumption for deoxygenation.
TOTAL (Cradle-to-Gate)	0.075	0.117	Without Biogenic Carbon Credit
Biogenic Carbon Credit	0.000	-0.035	Credit for biogenic CO2 absorbed during biomass growth.
TOTAL NET (Cradle-to-Gate)	0.075	0.082	With Biogenic Carbon Credit

5. Sensitivity Analysis Protocol

• Parameter Variation: Systematically vary key parameters (±20%): biomass intermediate yield, H2 consumption rate, biomass transport distance, and grid electricity carbon intensity.
• Allocation Method Test: Compare results using system expansion versus energy-based allocation for multi-output processes (e.g., pyrolysis char).
• Goal: Identify which parameters most significantly influence the final GHG result and the break-even point for environmental benefit.

6. The Scientist's Toolkit: Research Reagent Solutions

Item	Function in Co-processing LCA Research
Stabilized Pyrolysis Oil	Representative biomass intermediate; requires characterization (O, H2O content) for blend formulation.
Vacuum Gas Oil (VOO)	Fossil baseline feedstock for blending; provides benchmark for yield comparisons.
FCC or Hydrotreating Catalyst	Industry-standard catalyst to simulate real refinery conversion kinetics and selectivity.
¹⁴C (Radiocarbon) Analysis	Essential for quantifying biogenic vs. fossil carbon fraction in co-processed liquid fuels.
High-Pressure Parr Reactor	Laboratory-scale system for generating primary mass/energy balance data under controlled conditions.
Micro-GC / Gas Analyzer	For real-time analysis of gaseous products (CO, CO2, light hydrocarbons) from co-processing runs.
LCA Software (e.g., OpenLCA, SimaPro)	Platform for building LCI model, applying LCIA methods, and conducting sensitivity analyses.
Ecoinvent or GREET Database	Source of secondary, peer-reviewed LCI data for background processes (electricity, chemicals, transport).

7. Visualization Diagrams

LCA Phases & Iteration

Co-processing LCA System Boundary

Comparative Review of Technology Readiness Levels (TRL) for Different Pathways

Application Notes

Within the broader thesis on co-processing biomass intermediates in petroleum refineries, the assessment of Technology Readiness Levels (TRL) is critical for prioritizing research and development investments. This review compares the TRLs of three primary technological pathways for integrating biorenewable feedstocks into existing refinery infrastructure: Catalytic Hydrotreating, Fluid Catalytic Cracking (FCC) Co-processing, and Hydrodeoxygenation (HDO) with Full Upgrading. The current state (as of 2024-2025) indicates that these pathways occupy distinct positions on the development scale, from pilot-scale demonstration to early commercial deployment, largely dependent on the complexity of the oxygen removal and hydrocarbon reconstruction required.

Pathway 1, Catalytic Hydrotreating of Vegetable Oils/Fats, is the most mature, with several commercial units operating globally. It benefits from the direct analogy to petroleum hydrotreating. Pathway 2, FCC Co-processing of Pyrolysis Bio-Oils or Lignocellulosic Intermediates, faces significant challenges due to the high oxygenate and water content of the feed, leading to catalyst deactivation and unit corrosion. It remains largely at the pilot/demonstration stage. Pathway 3, Integrated Hydrodeoxygenation (HDO) and Hydrocracking to Renewable Fuels, represents a more bespoke, intensive processing route. While HDO catalysis is advancing rapidly, the integrated process at refinery-relevant scale is still being validated.

The primary bottlenecks for advancing TRL are consistent feedstock quality, catalyst lifetime under bio-feed conditions, and the economic viability of required unit modifications. Successful commercialization hinges on robust protocols for feedstock pretreatment, standardized catalyst testing, and clear sustainability metrics.

Quantitative TRL Assessment Table

Table 1: Comparative TRL Assessment for Co-processing Pathways (2024-2025)

Pathway	Description	Key Biomass Intermediate	Typical Target Products	Current TRL (Est.)	Key Technical Challenges
Catalytic Hydrotreating	Direct hydrotreating in diesel hydrotreater or dedicated unit.	Vegetable oils, animal fats, used cooking oil.	Renewable diesel (RD), Sustainable Aviation Fuel (SAF).	TRL 9 (Commercial)	Feedstock cost & availability, H2 consumption, glycerol management.
FCC Co-processing	Injection of bio-intermediate into existing FCC feedstock.	Pyrolysis bio-oil, hydrotreated pyrolysis oil, liquefied biomass.	Gasoline-range aromatics, olefins.	TRL 6-7 (Pilot/Demonstration)	High oxygen content → coke/water yield, catalyst deactivation, corrosion.
Integrated HDO + Upgrading	Stand-alone two-step catalytic deoxygenation & isomerization/cracking.	Pyrolysis bio-oil, lignin oils, sugars.	RD, SAF, Renewable gasoline.	TRL 5-6 (Lab/Pilot Scale)	Catalyst stability, selective C-O cleavage, separation of aqueous phases.

Table 2: Key Performance Metrics by Pathway

Pathway	Typical Oxygen Removal (%)	Estimated Yield to Fuel (wt%)	Key Catalyst Types	Major R&D Focus Areas
Catalytic Hydrotreating	>99	75-85	NiMo, CoMo sulfided on Al2O3	Feed flexibility, co-processing limits (<10% bio).
FCC Co-processing	70-90 (via decarboxylation/cracking)	20-40 (to liquid fuel)	Zeolite Y (ZSM-5 additives)	Feed stabilization, in-situ catalyst regeneration.
Integrated HDO + Upgrading	>95	50-70	Noble metals (Pt, Pd), Sulfided NiMo, Carbides	Bifunctional catalyst design, reactor fouling mitigation.

Experimental Protocols

Protocol 1: Bench-Scale Catalytic Hydrotreating Co-processing Test

Objective: To evaluate the performance and deactivation of a commercial hydrotreating catalyst when co-processing a 10% blend of hydrotreated vegetable oil (HVO) with straight-run gas oil. Materials: See Scientist's Toolkit. Procedure:

• Catalyst Loading & Activation: Load 10 mL of sulfided NiMo/Al2O3 catalyst pellets (250-500 µm) into a fixed-bed, down-flow reactor. Activate in-situ under 50 mL/min H2 at 320°C and 5.0 MPa for 12 hours.
• Baseline Run: Introduce 100% straight-run gas oil feed at a Liquid Hourly Space Velocity (LHSV) of 2.0 h⁻¹. Maintain reaction conditions at 330°C, 5.0 MPa, and a H2/oil ratio of 350 Nm³/m³. Collect liquid product every 24 hours for 7 days. Analyze for sulfur, nitrogen, and density.
• Co-processing Run: Switch feed to a 90:10 vol% blend of straight-run gas oil and HVO. Maintain identical operating conditions. Collect liquid product samples at 6, 12, 24, 48, 72, 120, and 168 hours on stream.
• Product Analysis: Analyze all liquid products via Simulated Distillation (ASTM D2887), Sulfur/Nitrogen analysis (ASTM D5453/D4629), and Gas Chromatography for hydrocarbon distribution. Monitor gaseous products (C1-C4, H2S, COx) via online micro-GC.
• Post-run Analysis: After 168 hours, cool reactor under H2, unload catalyst. Characterize spent catalyst via Thermogravimetric Analysis (TGA) for coke burn-off, and X-ray Photoelectron Spectroscopy (XPS) for surface composition.

Protocol 2: Microactivity Test (MAT) for FCC Co-processing

Objective: To assess the yield structure and catalyst deactivation during co-processing of conventional vacuum gasoil (VGO) with fast pyrolysis bio-oil. Materials: See Scientist's Toolkit. Procedure:

• Feed Preparation: Stabilize pyrolysis bio-oil by mild hydrotreatment (optional protocol). Blend 5 wt% of stabilized bio-oil with 95 wt% VGO. Homogenize via ultrasonic mixing.
• Catalyst Preparation: Use equilibrium FCC catalyst (E-CAT) from a commercial unit. De-gas at 500°C for 1 hour. Load 4.0 g into the MAT reactor.
• Reaction Cycle: Pre-heat catalyst bed to 550°C. Inject 1.33 g of feed (cat/oil ratio = 3) over 75 seconds using a syringe pump. Strip products with N2 for 525 seconds.
• Product Collection & Analysis: Liquid products are collected in a chilled receiver and analyzed by Simulated Distillation and GC-MS. Gaseous products (dry gas, LPG) are collected in a gas burette and analyzed by GC. Coke on catalyst is determined by combustion in a separate unit.
• Data Interpretation: Compare yield structure (gasoline, LCO, coke, dry gas) and product quality (oxygenate content, olefinicity) against a 100% VGO baseline run.

Visualization

Diagram 1: TRL Progression for Biomass Co-processing Pathways

Diagram 2: Experimental Workflow for Bench-Scale Co-processing

The Scientist's Toolkit

Table 3: Key Research Reagent Solutions & Materials for Co-processing Experiments

Item	Function & Relevance
Sulfided NiMo/Al₂O₃ Catalyst	Standard hydrotreating catalyst; tests deoxygenation, denitrogenation, and desulfurization activity in bio-feed environment.
Equilibrium FCC Catalyst (E-CAT)	Realistic catalyst for MAT tests; assesses bio-oil impact on yield and deactivation in cracking environment.
Model Oxygenate Compounds (e.g., Guaiacol, Furfural, Acetic Acid)	Used in fundamental studies to probe specific reaction pathways (HDO, decarboxylation) on novel catalysts.
Hydrotreated Vegetable Oil (HVO)	Representative low-oxygen, paraffinic bio-intermediate for co-processing in hydrotreaters and FCC units.
Stabilized Pyrolysis Bio-Oil	Key intermediate for FCC/HDO pathways; requires stabilization (e.g., mild hydrotreatment) to prevent polymerization.
High-Pressure Fixed-Bed Reactor System	Core unit for continuous, steady-state evaluation of catalysts under refinery-relevant pressures (3-10 MPa) and temperatures.
Microactivity Test (MAT) Unit	Standardized fluidized-bed reactor for rapid screening of FCC catalyst performance and yield structure.
Online Micro-Gas Chromatograph (µ-GC)	For real-time analysis of permanent gases (H2, CO, CO2, C1-C4) crucial for tracking deoxygenation mechanisms.

1. Application Notes: Regulatory & Economic Framework for Co-processing Research

Co-processing biomass intermediates (e.g., pyrolysis oil, hydrotreated vegetable oil) in existing petroleum refinery units represents a pivotal pathway for decarbonizing the transportation fuels sector. Its commercial viability and research direction are directly governed by policy and market drivers, primarily Renewable Fuel Standards (RFS) and carbon credit incentives. For researchers, these drivers define the technical targets (e.g., carbon intensity (CI) score, blend percentage) and economic parameters for process development.

1.1 Key Policy Instruments: Quantitative Targets

Policy/Program	Jurisdiction	Key Quantitative Target	Relevance to Co-processing
Renewable Fuel Standard (RFS2)	United States	36 billion gallons of renewable fuel by 2022; Annual volume standards set by EPA.	Co-processed fuels can generate Renewable Identification Numbers (RINs), specifically D4 (biomass-based diesel) or D7 (cellulosic diesel) credits, depending on feedstock and pathway approval.
Renewable Energy Directive II/III (RED II/III)	European Union	Minimum 29% (RED II) to 32% (RED III) renewable energy in transport by 2030; Advanced fuel sub-targets.	Co-processed fuels contribute to the renewable energy share, with double counting for some advanced feeds. CI savings vs. fossil comparator must be >65% for advanced biofuels.
Low Carbon Fuel Standard (LCFS)	California, Canada, other states	CI reduction of >20% by 2030 (CA). Credit trading market (~$80-$100/ton CO₂e in CA, 2023-2024).	Co-processing research must achieve CI scores low enough to generate valuable carbon credits. LCFS credit revenue is a key economic driver.
45Q Tax Credit	United States	$85/ton CO₂ for permanent geologic storage; $60/ton for utilized CO₂ (enhanced oil recovery).	Incentivizes integration of carbon capture and storage (CCS) with co-processing to achieve ultra-low CI fuels.

1.2 Critical Research Parameters Derived from Policies

• Carbon Intensity (CI) Modeling: Research must utilize approved lifecycle analysis (LCA) models (e.g., GREET, GHGenius) to calculate CI score (gCO₂e/MJ) for the co-processing pathway.
• Blend Ratio Optimization: Experiments must determine maximum permissible blend ratio of biomass intermediate with petroleum feed without negatively impacting catalyst lifetime, product quality, or unit operability, as this impacts total renewable volume.
• Feedstock Eligibility: Research scope is constrained to policy-approved feedstocks (e.g., agricultural residues, forestry waste, non-food oils) to qualify for advanced fuel credits.

2. Experimental Protocols

Protocol 1: Lifecycle Carbon Intensity Assessment for a Co-processing Pathway Objective: To calculate the cradle-to-gate CI score for diesel produced via co-processing fast pyrolysis oil in a refinery hydrotreater. Materials: GREET model software, feedstock production data, pyrolysis process energy data, refinery utility data, transportation logistics data. Methodology:

• System Boundary Definition: Establish assessment boundaries: feedstock cultivation/collection, feedstock transport, pyrolysis oil production, oil transport, co-processing (hydrogen consumption, utilities), petroleum fraction allocation.
• Data Collection: Gather primary data for co-processing stage: measure natural gas and electricity consumption per barrel of pyrolysis oil processed during pilot runs. Use literature or industry data for upstream stages if primary data is unavailable.
• Allocation Method: Apply energy-based allocation (or marginal allocation) to partition emissions between the renewable and fossil portions of the co-processed product stream.
• Modeling: Input mass and energy balances into the GREET model. Use the "Co-processing of Bio-oils in Petroleum Refineries" pathway template or create a custom pathway.
• Sensitivity Analysis: Vary key parameters (e.g., hydrogen source, grid electricity CI, feedstock transportation distance) to identify major CI contributors and research targets for reduction.

Protocol 2: Hydrotreater Catalyst Stability Test under Co-processing Conditions Objective: To evaluate the deactivation rate of a standard hydrotreating catalyst when co-processing 10% v/v pyrolysis oil with vacuum gas oil. Materials: Fixed-bed bench-scale hydrotreater reactor, commercial NiMo/Al₂O₃ catalyst, vacuum gas oil, stabilized pyrolysis oil, high-pressure hydrogen, gas chromatograph, total acid number (TAN) titrator. Methodology:

• Catalyst Loading & Activation: Load 50 mL of catalyst into reactor. Activate via in-situ sulfidation using a 3% v/v DMDS in gas oil stream at 320°C, 5.0 MPa H₂ pressure for 12 hours.
• Baseline Operation: Establish baseline activity with 100% vacuum gas oil feed at standard conditions (T=370°C, P=7.0 MPa, LHSV=1.0 h⁻¹, H₂/oil ratio=500 L/L). Monitor product sulfur content daily until stable.
• Co-processing Operation: Switch feed to a blend of 10% v/v pyrolysis oil and 90% v/v gas oil. Maintain identical operating conditions.
• Monitoring & Analysis:
  • Daily: Measure product density, sulfur content (ASTM D4294), and nitrogen content.
  • Every 72 hours: Measure TAN of liquid product (ASTM D664).
  • Weekly: Perform GC analysis of liquid product to track hydrocarbon distribution.
• Termination: Run experiment for 1000 hours. Perform post-mortem catalyst analysis: Thermogravimetric Analysis (TGA) for coke build-up, X-ray Photoelectron Spectroscopy (XPS) for surface composition.

3. Visualizations

Title: Policy and Market Drivers Define Research Targets

Title: Carbon Intensity Assessment Workflow

4. The Scientist's Toolkit: Key Research Reagent Solutions & Materials

Item	Function / Relevance
Stabilized Fast Pyrolysis Oil	Primary biomass intermediate. Must be pre-treated (e.g., filtered, mildly hydrotreated) to reduce coking tendency during co-processing experiments.
Model Compound Mixtures	Surrogates for complex bio-oils (e.g., guaiacol, acetic acid, furfural in decane) used for fundamental catalyst poisoning studies.
Bench-Scale Fixed-Bed Reactor System	Mimics refinery hydrotreater/ FCC unit conditions. Essential for evaluating catalyst performance, product yield, and operability under pressure.
Sulfiding Agent (Di-methyl disulfide, DMDS)	Used for in-situ activation of hydrotreating catalysts (NiMo, CoMo) prior to co-processing experiments.
Certified Reference Gases (H₂, H₂S in H₂, 5%O₂/He)	For reactor operation, catalyst sulfidation, and catalyst characterization (e.g., temperature-programmed techniques).
LCA Software (GREET, SimaPro, Gabi)	Required for CI calculation and compliance with regulatory methodology for credit generation.
Pulse Chemisorption Analyzer	Measures active metal dispersion and acid site density on fresh and spent catalysts—critical for deactivation studies.

Conclusion

Co-processing biomass intermediates in petroleum refineries presents a pragmatic and capital-efficient transition strategy towards sustainable hydrocarbon production. The foundational science confirms the technical feasibility of integrating bio-oils with conventional feeds, albeit with careful management of oxygenates and acidity. Methodological advancements in hydrotreating and FCC integration show promising yields of renewable diesel and gasoline-range hydrocarbons. However, long-term operational viability hinges on solving persistent troubleshooting issues, primarily catalyst longevity and hydrogen consumption. Validation through rigorous TEA and LCA indicates that, while currently challenged by economics, co-processing can be competitive under supportive carbon policy frameworks. Future directions must focus on developing more robust and selective catalysts, optimizing low-hydrogen pathways, and scaling integrated pilot demonstrations to de-risk technology for commercial adoption, ultimately positioning refinery co-processing as a critical component in the decarbonization of the transport fuel sector.