Fischer-Tropsch synthesis (FTS) is the preferred basis for the indirect liquefaction of coal and biomass for the production of liquid transportation fuels. Conventional FTS is highly unselective and produces lots of solid wax that requires additional equipment to convert the wax through a hydrogen intense process before it can be fractionated into separate liquid transportation fuels. This significantly increases both capital and operating costs for both treating the waxes and the generation of the hydrogen.
Based upon the results of experiments conducted under DOE/NETL sponsored cooperative agreement to demonstrate a compact, pressurized, high temperature reformer and a highly selective cobalt-zeolite hybrid Fischer-Tropsch (FT) catalyst a techno-economic analysis (TEA) and life-cycle analysis (LCA) was conducted to show the effects of these new technologies when compared to conventional indirect liquefaction coal-to-liquid (CTL).
The TEA showed that the improved technologies were able to reduce the capital cost of the indirect CTL process by; eliminating the need for several parasitic gas cleaning steps, eliminating the need for FTS product upgrading, and reducing the need for hydrogen generation. These cost reductions improved the economic competitiveness of the CTL process. The LCA showed that the addition of a moderate amount of biomass reduced the overall greenhouse gas emissions associated with the liquid fuels below that of a comparable petroleum derived fuel. The addition of CO2 capture technology can further reduce the greenhouse gas emissions, however, the associated costs can significantly alter the cost competitiveness.