Production Of Liquid Fuels From Coal By The Fischer Tropsch Synthesis

Large U.S. coal reserves and viable technology make promising a domestic industry producing liquid fuels from coal. Weighing benefits, costs, and environmental issues, a productive and robust U.S. strategy is to promote a limited amount of early commercial experience in coal-to-liquids production and to prepare the foundation for managing associated greenhouse-gas emissions, both in a way that reduces uncertainties and builds future capabilities.

As the price of crude oil sets a record high, liquid transportation fuels synthesized from coal, natural gas, and biomass are proposed as one solution to reducing dependency on imported petroleum and strained refinery capacity. The technology to do so developed from processes that directly and indirectly convert coal into liquid fuel. Congress now faces decisions on whether, and to what extent, it should support such a solution. Lacking domestic petroleum resources, but abundant in coal, Germany built synthetic fuel plants during World War II that employed the Bergius coal hydrogenation process (direct liquefaction), and Fischer-Tropsch synthesis (indirect). The United States attempted to capitalize on the German experience after World War II. Despite considerable investment in synthetic fuel research and development, the United States cut support for commercialization when crude oil prices dropped and supplies stabilized in the mid-1980s. Since then, several synthetic fuels plants have been constructed around the world that convert coal, natural gas, or biomass to liquid fuels using the Fischer-Tropsch process. Several private ventures in the United States are now studying the feasibility of constructing Fischer-Tropsch synthetic fuel plants based on coal, natural gas, and biomass. Proposals to expand the use of coal to synthesize transportation fuels have generated much opposition, particularly because the carbon dioxide (CO2) produced in the Fischer-Tropsch process is a greenhouse gas associated with global warming. Also, opponents claim that coal-based synthesis, in particular, is inefficient and thus prohibitively expensive. Proponents counter that Fischer-Tropsch technology provides a means of capturing carbon dioxide for geological sequestration (though a promising solution, sequestration remains unproven on an industrial scale) and that it appears economically viable in a sustained crude oil price range above $40 to $45 per barrel. Fischer-Tropsch synthesis is well suited to producing middle-distillate range fuels like diesel and jet. The diesel produced is superior to conventionally refined diesel in terms of higher cetane-number and low sulfur content. Overall, middle distillate fuels represent roughly a quarter of U.S. refinery production, which is primarily driven by the demand for gasoline. In order for a synthetic fuels industry (whether coal, natural gas, or biomass based) to begin rivaling or even supplanting conventional petroleum refining, a major shift in transportation mode toward diesel engine light-passenger vehicles would have to occur. Coal-to-liquids would also compete for the same resources needed for electric power generation, and the rail capacity currently supporting their demand. Recent energy legislation promotes research on capturing and storing greenhouse gas emissions and improving vehicle fuel efficiency, among other goals. Fisher-Tropsch fuels present the paradox of high carbon emissions associated with production versus lower carbon emissions associated with their use.