Coal

Name:
Coal
Detailed information:
A natural, solid, combustible material formed from prehistoric plant life, it occurs in layers or veins in sedimentary rocks. It is far more plentiful than petroleum in the U.S. an important source of heat and energy. It occurs chiefly in West Virginia and Kentucky, as well as in Wyoming and other western states. Much of it is too high in sulfur content to meet desirable pollution standards unless sulfur is removed by scrubbing. Chemically, coal is a macromolecular network composed of groups of polynuclear aromatic rings, to which are attached subordinate rings connected by oxygen, sulfur, and aliphatic bridges. This extended open structure is conducive to catalytic reactions, which in effect subdivide it into smaller molecules that can be defined readily. Coal is an important source of chemical raw materials. Pyrolysis (destructive distillation) yields coal tar and hydrocarbon gases that can be upgraded by hydrogenation or methanation to synthetic crude oil and fuel gas, respectively. Catalytic hydrogenation yields hydrocarbon oils and gasoline. Gasification produces carbon monoxide and hydrogen (synthesis gas), from which ammonia and other products can be made. Numerous processes for adapting these reactions to large-scale production of fuel oil and gasoline have been developed in the U.S., but none has yet proved economically successful. The process is being used abroad (Lurgi and Sasol methods).

Hazard:

TLV: 2 mg/m3 respirable dust.

See Gasification; Hydrogenolysis; Hydrosolvation; Peat; Lignite.