The Techno-Economic Basis for Coproduct Manufacturing To Enable Hydrocarbon Fuel Production from Lignocellulosic Biomass

Abstract

Biorefinery process development relies on techno-economic analysis (TEA) to identify primary cost drivers, prioritize research directions, and mitigate technical risk for scale-up through development of detailed process designs. Here, we conduct TEA of a model 2000 dry metric ton-per-day lignocellulosic biorefinery that employs a two-step pretreatment and enzymatic hydrolysis to produce biomass-derived sugars, followed by biological lipid production, lipid recovery, and catalytic hydrotreating to produce renewable diesel blendstock (RDB). On the basis of projected near-term technical feasibility of these steps, we predict that RDB could be produced at a minimum fuel selling price (MFSP) of USD $9.55/gasoline-gallon-equivalent (GGE), predicated on the need for improvements in the lipid productivity and yield beyond current benchmark performance. This cost is significant given the limitations in scale and high costs for aerobic cultivation of oleaginous microbes and subsequent lipid extraction/recovery. In light of this predicted cost, we developed an alternative pathway which demonstrates that RDB costs could be substantially reduced in the near term if upgradeable fractions of biomass, in this case hemicellulose-derived sugars, are diverted to coproducts of sufficient value and market size; here, we use succinic acid as an example coproduct. The coproduction model predicts an MFSP of USD $5.28/GGE when leaving conversion and yield parameters unchanged for the fuel production pathway, leading to a change in biorefinery RDB capacity from 24 to 15 MM GGE/year and 0.13 MM tons of succinic acid per year. Additional analysis demonstrates that beyond the near-term projections assumed in the models here, further reductions in the MFSP toward $2–3/GGE (which would be competitive with fossil-based hydrocarbon fuels) are possible with additional transformational improvements in the fuel and coproduct trains, especially in terms of carbon efficiency to both fuels and coproducts, recovery and purification of fuels and coproducts, and coproduct selection and price. Overall, this analysis documents potential economics for both a hydrocarbon fuel and bioproduct process pathway and highlights prioritized research directions beyond the current benchmark to enable hydrocarbon fuel production via an oleaginous microbial platform with simultaneous coproduct manufacturing from lignocellulosic biomass.

The costs of sugar production from different feedstocks and processing technologies

“…Biddy et al . reported that the fixed capital cost of a lignocellulosic sugar production plant with an annual capacity of 724 000 tonne of biomass was approximately 793.07 million dollars .…”

“…The material costs account for over 90% of the total production cost . Biddy et al . reported an estimated sugar production cost of $0.29/kg for an industrial‐scale operation …”

Direct conversion of cellulose into ethanol and ethyl‐β‐d‐glucoside via engineered Saccharomyces cerevisiae

“…The current market capacity for sugar‐based alkyl polyglycosides has been estimated around 90 kt in 2015, and expected to reach 135 kt in 2024 (Hill & Rhode, ; Shaw, ), and BASF SE, Shanghai Fine Chemicals, Dow Chemical Company, E. I. du Pont de Nemours and Company, Henkel, and LG Household & Health Care produce alkyl polyglucosides at commercial scale for manufacturing household detergents, industrial cleaners, personal care, and agricultural chemicals. In addition, it has been suggested that additional transformational improvements in the coproduction of fuel and chemicals enhanced the overall technoeconomic feasibility of the lignocellulosic biorefinery process (Biddy et al, ). Hence, coproduction of ethanol and ethyl‐β‐ d ‐glucoside could ultimately make a substantial impact on the overall technoeconomic feasibility of the SSF of cellulose.…”

Life‐cycle analysis of integrated biorefineries with co‐production of biofuels and bio‐based chemicals: co‐product handling methods and implications

“…To enable commercially viable hydrocarbon fuel production from lignocellulosic biomass, integrated biorefineries (IBRs) that co‐produce value‐added bio‐chemicals that can improve biorefinery economics have recently begun to be investigated. For example, innovative biochemical conversion technologies to deconstruct herbaceous biomass into sugars and subsequently upgrade sugars into renewable diesel blendstock (RDB) and succinic acid (SA) have been evaluated through TEA modeling . Techno‐economic analysis of this IBR concept with detailed process modeling has demonstrated that co‐production of SA can lower the minimum fuel selling price of hydrocarbon fuels substantially compared to a fuel‐only biorefinery design because the revenue of the co‐produced SA offsets the production costs of RDB.…”