Gasoline from coal and/or biomass with CO₂ capture and storage. 1. process designs and performance analysis

Fifteen alternative process designs for the production of synthetic gasoline from coal, biomass, or coal + biomass via gasification, methanol synthesis, and methanol-to-gasoline synthesis are analyzed, including some that produce a substantial electricity co-product and some that employ CO₂ capture, with CO₂ stored in deep saline formations or via injection for enhanced oil recovery. This paper reports process mass/energy balance simulation results and fuel-cycle greenhouse gas (GHG) emissions comparisons. A companion paper addresses economic and strategic issues. Key findings of the performance analysis include the following: (i) For two plants designed with the same liquid fuel output, but with one co-producing electricity, the additional feedstock needed for co-production is converted to electricity more efficiently than if that feedstock were used in a stand-alone power plant. (ii) Plants using only coal as feedstock have fuel-cycle GHG emissions greater than the conventional fossil fuels their products would displace, except for a co-production system with CO₂ capture and storage (CCS) which has about 40% less emissions. (iii) Plants that co-process 35% to 47% sustainably provided biomass with coal achieve net zero fuel-cycle GHG emissions. (iv) The logistics of biomass supply constrain these latter plants to modest scales (<10 000 barrels per day gasoline). (v) A biomass-only plant with CCS has highly negative net GHG emissions and a more severe scale constraint (∼4000 bbl/d).