systems analyses the DOE goal of $25/bbl (1991 dollars) for liquids from coal can be reached.

The aforementioned estimate based on Wilsonville data concerned dedicated coal liquefaction plants. Coproduction of liquids and electricity with advanced gasification systems can be expected to reduce costs. The reduction would likely be significant but probably less than the $5 to $7/bbl estimated for F-T liquefaction. Coprocessing of coal with residual fuel or tar in oil refineries has been studied by both industry and DOE.

While use of coal introduces both coal and ash handling requirements, improved process performance and continued low-cost of coal are expected to revive commercial interest in the mid-term period (2006-2020) if oil prices follow EIA projections (EIA, 1994). Several research areas offer promise for reducing the cost and improving the efficiency of direct liquefaction by hydrogenation: use of raw coal gasifier product with a catalyst capable of in situ shifting of CO to H2, removal of the oxygen in coal as CO2 rather than water, use of a low-pressure reactor, and minimized production of light hydrocarbons.

Direct Coal Liquefaction by Pyrolysis

Controlled heating of coal in pyrolysis can produce modest yields of liquids. The heat of pyrolysis is small, and, if the char product can be used without cooling, high thermal efficiencies can be achieved. The pyrolysis liquids are low in hydrogen and high in oxygen compared to petroleum residuum or bitumen but could be coprocessed with bitumen or fed to a direct coal liquefaction unit. Their tendency to polymerize on storage limits their use as a supplementary fuel for power generation without further processing.

While probably of lower value to a refinery than bitumen, it seems possible that coproduction with gasification could make pyrolysis liquids competitive with tar in the same period as deployment of advanced power generation systems. DOE studied coproduction of pyrolysis char and coke (mild gasification) and began construction of demonstration facilities, but no further funding has been requested in the FY 1995 budget. A CCT demonstration of this technology using low-sulfur Western coal is under way; the plan is to market pyrolysis liquids as power plant fuel oil and to burn the coke.

Coal Refineries and Coproduct Systems

The energy industries are mostly specialized, oriented to a narrow range of products and markets. Electric utilities supply electricity along with some steam to local users; oil refineries supply liquid fuels along with some petrochemical feedstocks; and gas suppliers collect, purify, and transmit natural gas to end users. Government regulations differ for these areas, and separate specialty business units have been established to deal with these separate regulatory systems.

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