NREL is a national laboratory of the U.S. Department of Energy, Office of Energy 

Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

In-Situ Catalytic Fast Pyrolysis 

Technology Pathway

Mary Biddy and Abhijit Dutta

National Renewable Energy Laboratory

Susanne Jones and Aye Meyer

Pacific Northwest National Laboratory

NREL is a national laboratory of the U.S. Department of Energy, 

Office of Energy Efficiency & Renewable Energy, operated by the 

Alliance for Sustainable Energy, LLC, under contract 

DE-AC36-08GO28308.

Pacific Northwest National Laboratory is operated by Battelle for the 

United States Department of Energy under contract 

DE-AC05-76RL01830.

Technical Report

NREL/TP-5100-58056 

PNNL-22320

March 2013

Prepared for the U.S. Department of Energy Bioenergy Technologies Office
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In-Situ Catalytic Fast 

Pyrolysis Technology 

Pathway 

Mary Biddy and Abhijit Dutta

National Renewable Energy Laboratory

Susanne Jones and Aye Meyer

Pacific Northwest National Laboratory

NREL is a national laboratory of the U.S. Department of Energy, 

Office of Energy Efficiency & Renewable Energy, operated by the 

Alliance for Sustainable Energy, LLC, under contract 

DE-AC36-08GO28308.

Pacific Northwest National Laboratory is operated by Battelle for the 

United States Department of Energy under contract 

DE-AC05-76RL01830.

Technical Report 

NREL/TP-5100-58056 

PNNL-22320

March 2013

Prepared for the U.S. Department of Energy Bioenergy Technologies Office
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1 

In-Situ Catalytic Fast Pyrolysis

Developing Technology Pathway Cases to Understand the Cost of 

Converting Biomass to Hydrocarbon Fuels

In support of the Bioenergy Technologies Office, the National Renewable Energy Laboratory 

(NREL) and the Pacific Northwest National Laboratory (PNNL) are undertaking studies of 

biomass conversion technologies to hydrocarbon fuels to identify barriers and target research 

toward reducing conversion costs. 

Process designs and preliminary economic estimates for each of these pathway cases were 

developed using rigorous modeling tools (Aspen Plus and Chemcad). These analyses 

incorporated the best information available at the time of development, including data from 

recent pilot- and bench-scale demonstrations, collaborative industrial and academic partners, and 

published literature and patents. The economic results of these analyses are in the process of 

further refinement and will be published in FY13 and FY14 design reports. This report 

summarizes the preliminary technical data used for the models and identified data gaps.

This technology pathway case investigates converting woody biomass using in-situ catalytic fast 

pyrolysis followed by upgrading to gasoline-, diesel-, and jet-range hydrocarbon blendstocks. 

Technical barriers and key research needs that should be pursued for this pathway to be 

competitive with petroleum-derived blendstocks have been identified. 

Process Block Diagram

Key Highlights

• In-situ vapor phase catalytic upgrading of fast pyrolysis vapors combines direct 

liquefaction of biomass by pyrolysis and pyrolysis vapor upgrading in the same vessel. 

• In-situ catalytic pyrolysis has the potential to reduce costs associated with upgrading 

conventional fast pyrolysis oil to a hydrocarbon by producing a lower-oxygen-content 

-

Flue Gas

Liquid

Off-gas

Heat Integration and Power Generation

Hydrogen 

Plant

Wastewater 

Treatment

Feed 

Handling & 

Preparation

Catalytic 

Pyrolysis and 

Quench

Catalytic 

Hydrotreating & 

Product 

Fractionation

Woody 

Biomass

Process Heat 

and Power 

Integration Off-gas

H2

Hydrocarbon 

Biofuels (i.e., 

Gasoline, 

Diesel, Jet) 
2 

intermediate phase with lower associated water. Hydrogen consumption during final 

upgrading to a hydrocarbon will also be reduced. 

• The addition of the vapor phase upgrading catalyst to the same reactor that pyrolyzes the 

biomass eliminates the external vapor phase reactor (ex-situ vapor phase upgrading), thus 

likely reducing capital and operating costs.

• The upgraded vapor’s lower reactivity may allow use of extended surface heat 

exchangers to recuperate heat and reduce the cooling water load when the vapors are 

condensed. 

• Important research needs for this pathway include developing catalysts with improved 

yields, stability, and lifetimes, maximizing overall conversion to the desired hydrocarbon 

product, optimizing CFP oil hydrotreating, and developing economic wastewater 

treatments. 

Process Design Details

Feed handling: Woody biomass is dried to approximately 10 wt% moisture and finely ground to 

2–6 mm. Waste heat streams from the pyrolysis section are used to dry the biomass. Drying and 

grinding costs are included in the feedstock costs (Jones and Male 2012). 

Catalytic fast pyrolysis: The model is based on a process consisting of a catalyst-containing 

circulating fluidized bed pyrolysis reactor, cyclones, and a combustor. Biomass is contacted with 

hot catalyst (and possibly a heat carrier) and fluidizing gas in a short residence time pyrolysis 

reactor at ~500°C and atmospheric pressure in the absence of air. Biomass is converted to 

condensable vapors and non-condensable gas, char, and coke. The evolved vapors are 

catalytically converted to less reactive compounds than those produced by uncatalyzed fast 

pyrolysis. Char and catalyst are separated from the vapor in cyclones and sent to a combustor to 

burn the char and any coke on the catalyst. This also serves to reheat the catalyst, which is 

returned to the pyrolysis reactor. Cyclones by themselves do not completely remove particulates 

from the product. Effective solids removal from the products is necessary to protect downstream 

equipment. This could be done, for example, by hot filtration of the vapor product prior to 

quenching or cold filtration of the liquid products. The pyrolysis vapors leaving the cyclone are 

condensed by heat recovery and trim cooled. Non-condensable gases are removed and two liquid 

phases are formed. The predominately organic phase is sent to hydrodeoxygenation and the 

predominately aqueous phase is routed to water treatment. 

Oxygen content of the organic phase and carbon content of the aqueous phase are dependent 

upon reaction time, temperature, and catalyst type. Yields are based on laboratory-scale 

experimental results for vapor phase upgrading (Dayton 2011a; Dayton 2011b). In-situ catalyst 

usage was not called out in these references. The nth plant cost model assumes two parallel 

catalytic pyrolyzers each processing 1,000 dry metric tonnes per day (tpd) of dry biomass. 

Catalytic hydrodeoxygenation: Catalytic pyrolysis oil is combined with hydrogen at 255°–

410°C and ~2,000 psi and is converted to hydrocarbon, water, and gas over a fixed bed reactor.

Depending upon the reactivity of the catalytic pyrolysis oil, two beds may be needed. The first 

bed is operated at the lower end of the temperature range to further reduce any remaining highly 

reactive compounds. The second bed is operated at the higher end of the temperature range, and 
3 

possibly at a lower space velocity to allow complete deoxygenation. The ideal goal is that the 

catalytic pyrolysis oil is of high enough quality so that only a single hydrotreater is needed. After 

cooling, the products are separated and the hydrocarbon product is distilled into C4 minus, 

gasoline range, and diesel range material. The targeted oxygen content of the upgraded oil is <1 

wt%. The cost model assumes that the product quality is sufficiently suitable for gasoline and 

diesel blendstocks. Wastewater is assumed to have <1 wt% carbon. The process model is based 

on experimental conditions and hydrodeoxygenation conversion for catalytic pyrolysis oil 

(Dayton 2011b; Zacher et al. 2011) and conventional pyrolysis oil (Elliott et al. 2009). The flow 

scheme is based on the upgrading section of the PNNL pyrolysis design case (Jones et al. 2009).

Hydrogen plant: Off-gases from the catalytic pyrolysis reactor, from the hydrodeoxygenation 

section, and from wastewater treatment are sent to a conventional hydrogen plant consisting of a 

steam reformer, water gas shift reactor, pressure swing adsorption unit, and heat recovery. 

Supplemental natural gas is not needed to satisfy the hydrogen demand based on the modeled 

results and the assumed level of catalytic pyrolysis oil oxygen content. No processing penalty is 

assumed for using off-gas in place of natural gas as reformer feed; this may be optimistic. The 

hydrogen plant size is within typical commercial scale. Design conditions are based on 

commercial-type systems running on natural gas (SRI Consulting 2007). Alternately, the 

fluidized bed reformer system developed for steam reforming of biomass syngas for the 2012 

ethanol demonstration (Dutta et al. 2011) can be used as the reformer for this process.

Wastewater treatment: The aqueous phase from catalytic pyrolysis likely contains acids, 

aldehydes, and phenolics. As no data yet exist for this treatment, it is assumed to be digestible in 

a process similar to the one described in NREL’s biochemical ethanol design report (Humbird et 

al. 2011). Off-gas from the digester is routed to the hydrogen plant. The process was modeled as 

a stoichiometric reactor with complete conversion to CO2 and CH4. 

Steam and power: Off-gases that are not needed for hydrogen generation are sent to a boiler for 

combustion to generate superheated steam. Steam not utilized in the process is sent for power 

generation in a turbine system. 

Data Gaps, Uncertainties, and Research Needs

The majority of the model is literature based and there may be little or no new data available in 

the next year. The goal of this pathway is to reach a minimum fuel selling price of $3/gallon of 

gasoline equivalent (in 2011 U.S. dollars). To reach this targeted product price, the key 

bottlenecks, uncertainties, and areas for further development are summarized as follows: 

• Demonstrate and optimize yield. Most of the literature data is based on ex-situ-type 

processing where pyrolysis vapors from the cyclone are upgraded in a separate reactor. 

There is very little data in the literature regarding pyrolysis combined with upgrading in a 

single vessel. Processing costs, organic losses to the aqueous phase, and extent of 

upgrading were estimated based on ex-situ processing. Coke production may be 

significant. The primary goal in optimizing this process is to retain as much carbon in the 

liquid product as possible while removing the highly reactive oxygen species. 

• Develop reactor design data. Little is known about the design and operation of the 

catalytic pyrolysis reactor. Research is needed to understand issues such as the effect of 
4 

biomass residence time, catalyst residence time, and the biomass-to-catalyst ratio, each of 

which is likely important for both performance and economics. It is also not known if an 

inert heat carrier, such as sand, will be needed. Heat and mass transfer effects need to be 

researched through experimental efforts on a continuous system consistent with the 

assumed design. Careful design of the product recovery scheme is needed to ensure 

product stability and mitigate fouling. Handling large amounts of solids will also need 

attention. Effective removal of solids is necessary to ensure no negative effects on 

downstream integration. 

• Develop and optimize pyrolysis catalyst. Catalyst maintenance and stability are 

unknown, as are regeneration protocols and lifetime. Mineral and carbon deposits may be 

difficult to remove. Testing with biomass and detailed characterization of catalyst 

performance and deactivation modes are needed. Catalysts developed for this process 

need to be both mechanically and thermally stable and robust to improve overall 

lifetimes. The catalyst must produce a catalytic pyrolysis oil product that is an 

improvement over conventional pyrolysis oil, and that oil must be produced in good 

yield. A fundamental understanding of the detailed reaction mechanisms and kinetics can 

enable the design of catalysts with optimal productivity rates and yields toward desired 

product slates. Investigating the solid/vapor interface chemistry and increasing the 

catalytic conversion will be key for catalyst improvements. Rational design and 

development of catalysts could be accomplished using a combination of computational 

and experimental techniques.

• Optimize hydrotreating. Hydrodeoxygenation upgrading may be performed in a single 

bed if the catalytic pyrolysis oil is of sufficiently low oxygen content or if the oxygen is 

contained within relatively unreactive species that do not readily polymerize. Parameter 

testing and development of compounds’ structure-reactivity relationships are needed.

Hydrodeoxygenation catalyst maintenance issues are unknown but should be easier to 

manage than processing raw fast pyrolysis oil. Long term catalyst testing, upgraded biooil speciation, and fuel quality tests are needed. There is a need to understand mass 

transfer issues of hydrogen in bio-oil and on the catalyst, as well as to determine how 

alkenes, aromatics, and oxygenates affect hydrogen usage. 

• Characterize fuels and intermediates. The final hydrocarbon products may not be of 

sufficient quality to use as a blendstock, which was assumed in the economics. Key 

properties such as cetane and octane, as well as flash points, smoke points, cloud or pour 

points, and distillation curves must be verified against gasoline and diesel specifications. 

Consideration should be given to production of refinery intermediates instead of finished 

fuels, and as such, better characterization of the catalytic pyrolysis oil is needed. The offgas composition should also be better characterized to verify its suitability as a hydrogen 

plant feedstock. 

• Establish optimum catalytic pyrolysis oil properties. A key part of the process design 

will be developing an understanding of effective process integration, specifically the 

trade-offs between the amount and quality of oil produced via catalytic pyrolysis and the 

impact this has on downstream hydrodeoxygenation. Higher quality oil requires less 

hydrodeoxygenation but the yield may be reduced from the catalytic pyrolysis step. 
5 

Lower quality oil will require higher severity hydrodeoxygenation but also may have 

higher yields.

• Determine optimum wastewater treatment. Wastewater treatment is largely 

unexplored, and anaerobic digestion may not be appropriate for the types of species 

present. There is a need to understand the impact of organic compounds on wastewater 

treatment, to understand the toxicity of trace compounds, and to minimize carbon loss to 

wastewater treatment. Research is needed to understand the conversion of organics in the 

aqueous phase to hydrogen, bio-products, and species that can rejoin the predominately 

organic phase. Consideration should also be given to alternate wastewater treatment

methods such as catalytic hydrothermal gasification. 

Summary and Next Steps

This study assessed the processing of woody biomass conversion via in-situ catalytic fast 

pyrolysis followed by upgrading and finishing to gasoline-, diesel-, and jet-range hydrocarbon 

blendstocks. A literature-based techno-economic analysis was performed to identify technology 

gaps, uncertainties, and research needed to achieve a minimum fuel selling price of $3/gallon of 

gasoline equivalent. A design case detailing this pathway will be developed in FY14. 

References

Agblevor, F.; Mante, O.; Abdoulmoumine, N.; McClung, R. (2010). “Production of Stable 

Biomass Pyrolysis Oils Using Fractional Catalytic Pyrolysis.” Energy & Fuels (24); pp. 4087-

4089. 

Czernik, S. (2011). “Catalytic Pyrolysis of Biomass at NREL.” Presented at TC Biomass 2011, 

Chicago, Illinois, September 27-30, 2011. 

Dayton, D. (2011a), “Catalytic Biomass Pyrolysis for Bio-Crude Production: Catalyst Screening 

and Process Development.” Presented at TC Biomass 2011, Chicago Illinois, September 27-30, 

2011. 

Dayton, D. (2011b). “Catalytic Deoxygenation of Biomass Pyrolysis Vapors to Improve Bio-Oil 

Stability.” Presented at the 2011 DOE/OBP Thermochemical Platform Review, February 16, 

2011. 

Dutta, A.; Talmadge, M.; Hensley, J.; Worley, M.; Dudgeon, D.; Barton, D.; Groendijk, P.; 

Ferrari, D.; Stears, B.; Searcy, E. M.; Wright, C. T.; Hess, J. R. (2011). Process Design and 

Economics for Conversion of Lignocellulosic Biomass to Ethanol: Thermochemical Pathway by 

Indirect Gasification and Mixed Alcohol Synthesis. NREL/TP-5100-51400. Golden, CO: 

National Renewable Energy Laboratory. 

Elliott, D.; Hart, T.; Neuenschwander, G.; Rotness, L.; Zacher, A. (2009). “Catalytic 

Hydroprocessing of Biomass Fast Pyrolysis Bio-Oil to Produce Hydrocarbon Products.” 

Environmental Progress & Sustainable Energy (28:3); pp. 441-449. 

Humbird, D.; Davis, R.; Tao, L.; Kinchin, C.; Hsu, D.; Aden, A.; Schoen, P.; Lukas, J.; Olthof, 

B.; Worley, M.; Sexton, D.; Dudgeon, D. (May 2011). Process Design and Economics for 
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Biochemical Conversion of Lignocellulosic Biomass to Ethanol: Dilute-Acid Pretreatment and 

Enzymatic Hydrolysis of Corn Stover. NREL/TP-5100-47764. Golden, CO: National Renewable 

Energy Laboratory. 

Jones, S.; Valkenburg, C.; Walton, C.; Elliott, D.; Holladay, J.; Stevens, D.; Kinchin, C.; Czernik, 

S. (February 2009). Production of Gasoline and Diesel from Biomass via Fast Pyrolysis, 

Hydrotreating and Hydrocracking: A Design Case. PNNL-18284. Richland, WA: Pacific 

Northwest National Laboratory.

Jones, S.; Male, J. (2012). Production of Gasoline and Diesel from Biomass via Fast Pyrolysis, 

Hydrotreating and Hydrocracking: 2011 State of Technology and Projections to 2017. PNNL 

22133. Richland, WA: Pacific Northwest National Laboratory. 

Mante, O.; Agblevor, F. (2011). “Catalytic Conversion of Biomass to Bio-Syncrude Oil.” 

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Pyrolysis of Biomass and Catalytic Hydrotreating to Liquid Transportation Fuels.” PNNL-SA82908. Presented at TC Biomass 2011, Chicago Illinois.