STATUS AND FUTURE OPPORTUNITIES FOR CONVERSION OF SYNTHESIS GAS TO LIQUID FUELS

This review provides an account and an evaluative assessment of technological advances in the manufacture of liquid fuels from synthesis gas (hydrogen and carbon oxides), and suggests opportunities for future research deemed promising for the installation of practical processes. Manufacture of syngas from coal, gas or biomass is not part of this review. Significant progress has been achieved for synthesis of oxygenate and hydrocarbon fuels on all technological levels: scientific research, engineering development and pioneering plant installations. For oxygenate fuels, improved synthesis technology has been provided by novel catalysts, innovative engineering for plant simplification, and methodology for coproduction of chemicals and of electricity. For hydrocarbon fuels, improvements have been achieved by utilizing fixed fluid bed synthesis, by a novel combination of middle distillate synthesis plus hydrocracking and by promising slurry phase operation. The review summarizes new understanding of the chemistry of syngas catalysis. Economic considerations are discussed, with new emphasis on fuel performance values. The main barrier to commercial production of synfuels is their cost relative to gasoline from petroleum. There are opportunities to improve synfuel economics by technology which has the potential: (a) to lower manufacturing cost by 10-30%; (b) to synthesize products which justify 25% higher prices (fuels of premium engine performance or chemical-electricity coproducts); and (c) to produce fuels with valuable environmental benefits. Liquid fuels from biomass may offer a special economic incentive if a future CO2 tax is imposed. Specific opportunities for future research, to develop new and improved technology for oxygenate and for hydrocarbon fuels, are suggested in terms of technical objectives and potential benefits. Promising research concepts are indicated, based on research advances discussed herein.