Understanding the role of Fischer-Tropsch reaction kinetics in techno-economic analysis for co-conversion of natural gas and biomass to liquid transportation fuels

With the increased availability of low-cost natural gas, the co-conversion of natural gas and biomass-to-liquid fuels has attracted attention from industry due to its potential for improving liquid fuel yields while lowering greenhouse gas emissions. This study provides an understanding of Fischer-Tropsch kinetics, improvements in processing strategies for hydrocarbon production, and of its impact on cost for the co-conversion of natural gas and biomass-to-transportation fuels. Studies that investigate the effect of Fischer-Tropsch reaction kinetics on techno-economic analysis can be used to develop process models that consider reaction stoichiometry and account for the effect of the paraffin-to-olefin ratio. We consider two processing scenarios: (1) one that does not employ a hydrocracker, and (2) the other where a hydrocracker serves as an integral part of the process scheme. Our analysis shows that co-processing natural gas not only facilitates the economic benefits of converting biomass-to-liquid fuels but also facilitates flexibility in process integration. The resulting minimum fuel selling price ranged from $2.47-$3.47/GGE (gallon gasoline equivalent) without the hydrocracker and ranged from $2.17-$3.60/GGE with the inclusion of the hydrocracker, for a 50 million GGE hydrocarbon fuel production facility and for varying blending ratios for biomass from 0-100% with natural gas. The hydrocracker helps to increase the production of diesel and jet fuels substantially, with carbon efficiencies of 50% attained for a chain growth probability of 0.87. The cost penalty comes from the capital expenses of the hydrocracker, and the expense may not be offset with hydrocarbon yield improvement. (c) 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.