Liquefaction of Victorian Brown Coal

Publisher Summary This chapter deals with the process of liquefaction of Victorian brown coal. Coal liquefaction is considered as an alternative to petroleum in countries when the rate of petroleum production could not keep up with the growing demand. A route to an efficient liquefaction lies in the development of suitable catalysts to lower capital investment and operating costs by improving the selectivity to the desired products, reducing operating severity and increasing throughput rates. One of the most expensive components in direct coal liquefaction is the cost of hydrogen. Hydrogen production is estimated to represent 15% to 40 % of the capital cost of a commercial plant. The investment cost escalates with increasing hydrogen requirement. For coals whose hydrogen content is the lowest of the available fossil fuel resources, it is necessary to add about 8 wt% hydrogen to produce gasoline and distillates. The use of catalysts helps to minimize the hydrogen consumption, approaching that required by stoichiometry, contributing to the reduction of cost. However, there is the cost of the catalyst itself, which is usually cited based on the use of very expensive metals as catalysts. Solvent/coal ratios in slurry and oil yield are also important factors influencing the cost of coal-derived oil. Reduction of the solvent/coal ratio can decrease the cost of coal liquefaction because the reactor efficiency increases in inverse proportion to the ratio.