A previous Iowa State University (ISU) analysis published in 2010 investigated the technical and economic feasibility of the fast pyrolysis and hydroprocessing of biomass, and concluded that the pathway could produce cellulosic biofuels for a minimum fuel selling price (MFSP) of $2.11/gal. The 2010 ISU study was largely theoretical in that no commercial-scale fast pyrolysis facilities were being constructed at the time of publication.The present analysis expands upon the 2010 ISU study by performing an updated techno-economic analysis of the fast pyrolysis and hydroprocessing pathway. Recent advances in pathway technology and commercialization and new parameters suggested by the recent literature are accounted for. The MFSP for a 2000 MTPD facility employing fast pyrolysis and hydroprocessing to convert corn stover to gasoline and diesel fuel is calculated to quantify the economic feasibility of the pathway.The present analysis determines the MFSP of gasoline and diesel fuel produced via fast pyrolysis and hydroprocessing to be $2.57/gal. This result indicates that the pathway could be competitive with petroleum, although not as competitive as suggested by the 2010 ISU study. The present analysis also demonstrates the sensitivity of the result to process assumptions. Keywords fast pyrolysis, hydroprocessing, catalytic pyrolysis, techno-economic analysis, Bioeconomy Institute, Mechanical Engineering Disciplines Industrial Engineering | Mechanical Engineering | Systems EngineeringComments NOTICE: This is the author's version of a work that was accepted for publication in Fuel. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently publishedin in Fuel, 106, April (2013) NOTICE: This is the author's version of a work that was accepted for publication in Fuel. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently publishedin in Fuel, 106, April (2013)

No abstract

Catalytic fast pyrolysis (CFP) offers a simple and robust route to convert raw lignocellulosic biomass to aromatic hydrocarbons. During CFP, cellulose, hemicellulose, and lignin are first thermally decomposed to bio-oil vapors that are further converted to aromatics in the presence of a ZSM-5 zeolite catalyst. The high temperatures required for CFP also favor coke formation, an undesired byproduct, through condensation of the oxygenated intermediates on ZSM-5′s outer surface and/or secondary reactions inside its micropores. Introducing mesopores through desilication represents a possible strategy to enhance mass transport and intracrystalline diffusion, and consequently favor aromatic production over undesired coke formation. Here, we study the effect of desilication on the structure, acidity, and performance of aluminum-rich ZSM-5. Detailed characterization of the obtained zeolite catalysts indicates that mild desilication conditions do not significantly affect the elemental composition, crystallographic structure, microporosity, and distribution of aluminum atoms in framework and extraframework sites. However, the number of accessible Brønsted acid sites increased by ∼50% as a result of the enhanced mesoporosity. Desilication increased the aromatic yields obtained for red oak pyrolysis (27.9%) compared to the parent zeolite (23.9%), without impacting the liquid product distribution (67.4% selectivity to benzene, toluene, and xylene). Our results suggest the catalytic performance could be further improved by enlarging the mouth of ink bottle shaped mesopores in order to further enhance mass transport between the gas phase and the zeolite's micropore network.

A techno-economic analysis of mild catalytic pyrolysis (CP) of woody biomass followed by upgrading of the partially deoxygenated pyrolysis liquid is performed to assess this pathway's economic feasibility for the production of hydrocarbon-based biofuels. The process achieves a fuel yield of 17.7 wt% and an energy conversion of 39%. Deoxygenation of the pyrolysis liquid requires 2.7 wt% hydrogen while saturation of aromatic rings in the pyrolysis liquid increases total hydrogen consumption to 6.4 wt%. Total project investment is $457 million with annual operating costs of $142 million for a 2000 metric ton per day facility. A minimum fuel selling price (MFSP) of $3.69/gal is estimated assuming 10% internal rate of return. Twentynine percent of the capital outlay is the result of including a co-generation system to consume heat generated from burning part of the off-gases from pyrolysis and upgrading and all of the coke during regeneration of catalysts. Forty-five percent of the MFSP arises from the cost of biomass feedstock. Hydrogen required for the upgrading process is generated using the balance of the process off-gases.The analysis reveals that an optimum design would include a cogeneration unit; however using natural gas for hydrogen generation is more favorable than using process off-gases as the feed. An uncertainty analysis indicates a probable fuel price of $3.03/gal, demonstrating the potential of the CP pathway as an alternative to petroleum-derived transportation fuels. AbstractA techno-economic analysis of mild catalytic pyrolysis (CP) of woody biomass followed by upgrading of the partially deoxygenated pyrolysis liquid is performed to assess this pathway's economic feasibility for the production of hydrocarbon-based biofuels. The process achieves a fuel yield of 17.7 wt% and an energy conversion of 39%. Deoxygenation of the pyrolysis liquid requires 2.7 wt% hydrogen while saturation of aromatic rings in the pyrolysis liquid increases total hydrogen consumption to 6.4 wt%.Total project investment is $457 million with annual operating costs of $142 million for a 2000 metric ton per day facility. A minimum fuel selling price (MFSP) of $3.69/gal is estimated assuming 10% internal rate of return. Twenty-nine percent of the capital outlay is the result of including a co-generation system to consume heat generated from burning part of the off-gases from pyrolysis and upgrading and all of the coke during regeneration of catalysts. Forty-five percent of the MFSP arises from the cost of biomass feedstock. Hydrogen required for the upgrading process is generated using the balance of the process off-gases.This is a manuscript of an article from Green Chemistry 16 (2014): 627, doi: 10.1039/C3GC41314D. Posted with permission. 2The analysis reveals that an optimum design would include a cogeneration unit; however using natural gas for hydrogen generation is more favorable than using process off-gases as the feed.An uncertainty analysis indicates a probable fuel price of $3.03/gal, demonstrating the potent...