What is "coal gas"

Coal \Coal\ (k[=o]l), n. [AS. col; akin to D. kool, OHG. chol, cholo, G. kohle, Icel. kol, pl., Sw. kol, Dan. kul; cf. Skr. jval to burn. Cf. Kiln, Collier.]

1. A thoroughly charred, and extinguished or still ignited, fragment from wood or other combustible substance; charcoal.

2. (Min.) A black, or brownish black, solid, combustible substance, dug from beds or veins in the earth to be used for fuel, and consisting, like charcoal, mainly of carbon, but more compact, and often affording, when heated, a large amount of volatile matter. Note: This word is often used adjectively, or as the first part of self-explaining compounds; as, coal-black; coal formation; coal scuttle; coal ship. etc. Note: In England the plural coals is used, for the broken mineral coal burned in grates, etc.; as, to put coals on the fire. In the United States the singular in a collective sense is the customary usage; as, a hod of coal. Age of coal plants. See Age of Acrogens, under Acrogen. Anthracite or Glance coal. See Anthracite. Bituminous coal. See under Bituminous. Blind coal. See under Blind. Brown coal or Brown Lignite. See Lignite. Caking coal, a bituminous coal, which softens and becomes pasty or semi-viscid when heated. On increasing the heat, the volatile products are driven off, and a coherent, grayish black, cellular mass of coke is left. Cannel coal, a very compact bituminous coal, of fine texture and dull luster. See Cannel coal. Coal bed (Geol.), a layer or stratum of mineral coal. Coal breaker, a structure including machines and machinery adapted for crushing, cleansing, and assorting coal. Coal field (Geol.), a region in which deposits of coal occur. Such regions have often a basinlike structure, and are hence called coal basins. See Basin. Coal gas, a variety of carbureted hydrogen, procured from bituminous coal, used in lighting streets, houses, etc., and for cooking and heating. Coal heaver, a man employed in carrying coal, and esp. in putting it in, and discharging it from, ships. Coal measures. (Geol.)

   1. Strata of coal with the attendant rocks.

   2. A subdivision of the carboniferous formation, between the millstone grit below and the Permian formation above, and including nearly all the workable coal beds of the world.

      Coal oil, a general name for mineral oils; petroleum.

      Coal plant (Geol.), one of the remains or impressions of plants found in the strata of the coal formation.

      Coal tar. See in the Vocabulary.

      To haul over the coals, to call to account; to scold or censure. [Colloq.]

      Wood coal. See Lignite.

n. (context petrochemistry English) The poisonous gas, used domestically for cooking etc and formerly for lighting, prepared by heating coal with steam; it is a mixture of hydrogen and carbon monoxide; synthesis gas or town gas.

n. gaseous mixture produced by distillation of bituminous coal and used for heating and lighting

Coal gas is a flammable gaseous fuel made from coal and supplied to the user via a piped distribution system. Town gas is a more general term referring to manufactured gaseous fuels produced for sale to consumers and municipalities.

Coal gas contains a variety of calorific gases including hydrogen, carbon monoxide, methane and volatile hydrocarbons together with small quantities of non-calorific gases such as carbon dioxide and nitrogen.

Prior to the development of natural gas supply and transmissionduring the 1940s and 1950s in the United States and during the late 1960s and 1970s in Great Britainvirtually all gas for fuel and lighting was manufactured from coal. Town gas was supplied to households via municipally-owned piped distribution systems.

Originally created as a by-product of the coking process, its use developed during the 19th and early 20th centuries tracking the industrial revolution and urbanization. By-products from the production process included coal tars and ammonia, which were important chemical feedstock for the dye and chemical industry with a wide range of artificial dyes being made from coal gas and coal tar. Facilities where the gas was produced were often known as a manufactured gas plant (MGP) or a gasworks.

The discovery of large reserves of natural gas in the North Sea off the UK coast during the early 1960s led to the expensive conversion or replacement of most of the nation's gas cookers and gas heaters, with the exception of Northern Ireland, from the late 1960s onwards.

The production process is distinct, both physically and chemically, from that used to create a range of gaseous fuels known variously as manufactured gas, syngas, hygas, Dowson gas, and producer gas. These gases are made by partial combustion of a wide variety of feed stocks in some mixture of air, oxygen, or steam, to reduce the latter to hydrogen and carbon dioxide although some destructive distillation may also occur.