Liquefaction

Abstract

AbstractTo eliminate much of the hardware and many of the processing steps involved in indirect liquefaction, an alternative is to add hydrogen directly to coal, intending to make liquids in one step. Direct liquefaction is simpler in concept, but still involves high temperatures and pressures and the need to convert the primary liquid products to clean, usable fuels. When petroleum is in short supply or prices are high, there is great interest in direct liquefaction. Direct liquefaction has been demonstrated to be commercially feasible, beginning with the Bergius-Bosch plants in Germany during 1939–1945. Research and development were rekindled after the oil price shocks and embargo of the 1970s. When oil is widely available at low price, there is scant interest. A direct liquefaction plant in China seems currently to be the world’s only commercial direct liquefaction plant.