9781422285534

36 Coal

into coal seams, pumping in oxygen or air under pressure, and collecting the coal gas. This can be burned as fuel or, in many cases, changed into yet another form, called syngas, or synthesis gas. Syngas is mainly hydrogen and carbon monoxide, and it has various uses as a fuel in power plants, factories, and vehicles. The coal gasification process is evolving all the time. Coal gas can be routed to making intermediate substances for gasoline and diesel production, or to produce hydrogen for the chemical industry and hydrogen-fuelled vehicles. Yet another outcome can be methane-based synthetic natural gas (SNG), also called substitute natural gas, which is used in the same way as regular natural gas. And there is another group of processes called direct coal-to-liquids (CTL), where coal is converted by various chemical means to liquid fuels such as gasoline and diesel, without the between stage of gasifying. Many of the coal-based technologies discussed above are interlinked, with the product from one becoming the raw material for the next. This is part of the shift to use the plentiful natural resource of coal in cleaner, more efficient ways. However, at present, nine-tenths of North American coal still is burned to generate electricity. Other Coal Products Coal is also used in the making of many other products, including: • various products made by paper, chemical, and pharmaceutical industries • creosote oil, naphthalene, phenol, and benzene • ammonia products such as nitric acid and agricultural fertilizers • solvents, dyes, fibers, and plastics • activated carbon in water and air filters • carbon fiber in mountain bikes, tennis racquets, racing cars, and similar products • cement, concrete, and other construction materials • cosmetics, hair shampoos, and toothpastes • lubricants, water repellents, and resins