Two methods of producing liquid fuels are direct coal liquefaction (DCL) and indirect coal liquefaction(ICL). In DCL the coal is directly contacted with a catalyst at elevated temperatures in the presence of added hydrogen.

The ICL process consists to two major steps:

1) gasification to produce a synthesis gas and

2) conversion of the gas to a liquid by synthesis over a catalyst in a Fischer-Tropsch process. Removal of the sulfur from the coal before passing the gas over the catalyst is necessary to prevent "poisoning" of the catalyst. Removal of the CO2 is also desirable to improve synthesis efficiency. Without mitigation coal liquefaction emits 7-10 times the CO2 of oil production. This deficiency is nearly totally eliminated in the coal gasification projects being demonstrated by DOE. DCL processes are more efficient than ICL processes, 67% vs 55%, but higher quality coal and a more complicated process is required for DCL. Combining coal liquefaction with electricity production leads to a much more efficient process that utilizes some of the heat that would otherwise be wasted.

 

in the where to ride?

 

One thing that comes out of new ways to extract "oil", is a variety of molecules that may have totally unexpected properties. For example, PAO synthetic oil (Mobil 1 and Amsoil), comes from a by-product of oil shale extraction.