West Biofuels Fuel Ethanol and Value-Added Chemicals from Biomass Residuals

The project team conducted research to advance the commercial readiness of a system to convert woody biomass residue into a mixed alcohol product high in renewable fuel ethanol. Woody biomass is a critically underutilized resource in California and this technology could enable a new market for this material, as well as a new in-state biofuels production sector. In addition, the process was shown to produce a fuel much lower in carbon intensity than current ethanol produced from corn, and which reduced criteria pollutant emissions and forest fire risk.

The researchers' approach utilized synthesis testing with a commercially available mixed alcohol synthesis catalyst on three different reactor scales to evaluate the technical and commercial viability of the process. The testing evaluated the synthesis of alcohols from syngas that is produced from a Fast Internally Circulating Fluidized Bed gasifier operating on woody biomass. The first system was a bench-scale reactor that was used for parameter testing to optimize a number of operating parameters including temperature, flow, pressure, and gas composition. A second larger bench-scale system was used to conduct 1,000 hours of on-stream testing with biomass syngas to look at performance degradation of the catalyst. The third system was constructed as a single reactor tube with cooling system, condenser, and gas recycling as it would be implemented in the commercial system. The project team was able to show a high conversion rate for the biomass-based syngas and a product stream high in ethanol and higher alcohols (primarily propanol) using the scaled process. Techno-economic analysis showed that this process reduced the capital cost of a benchmark system by about 10 percent, reducing the price per gallon of ethanol. In addition, the process yielded a 10-times-higher quantity of co-products like propanol, which have a potentially high market value than ethanol; if achieved, this would substantially lower the cost of producing ethanol. The project successfully demonstrated the catalytic pathway to make mixed alcohol product from woody biomass that shows commercial promise. The project team intends to further develop the process with further scale-out testing the integrated system for longer cycle times and scale-up testing with a demonstration scale system.