FUEL 85 |
| This article discusses means by which coal can be liquefied with as little as 0.5 weight percent addition of hydrogen, and the value-added products that can be manufactured. Historically, direct liquefaction has been used to produce synthetic crudes with characteristics analogous to petroleum crudes; i.e., the aim has been to achieve a synthetic crude which resembles sweet light petroleum crude as much as possible. Because coals have lower hydrogen-to-carbon ratio (mH/mC) than light petroleum crude, this means that about ten mass percent hydrogen must be added to the coal feedstock in order to give it the desired properties. In addition, coals tend to contain a high percentage of aromatic chemicals, which are less well suited to transportation fuels. Thus, extensive refining is required to convert coal to a light aliphatic crude. With less hydrogen consumption and less refining, coal feedstocks are likely to result in a heavy, aromatic synthetic crude rather than a light aliphatic crude. Yet, heavy aromatic crudes can be refined to produce value-added finished products, albeit with a somewhat different product suite than would be normally obtained from lighter crudes. In particular, the distillation “bottoms” from liquefied coal can result in value-added products such as mesophase pitch, binder pitch, impregnation pitch, needle grade coke, and anode grade coke, all of which are commodity products with established markets. A major application is the development of anode grade carbon for use in metals smelting. |
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Coal Conversion to Clean Liquid and Gaseous Fuels
8:15 AM-12:10 PM, Monday, August 20, 2007 Boston Park Plaza -- Chartes River Room, Oral
Division of Fuel Chemistry |