A coke battery consists of many coke ovens stacked together in rows. These ovens are tall chambers into which coal is loaded from the top through ports covered by lids. To avoid burning the coal, oxygen must be kept out of the coke ovens. After a heating cycle of 12 to 36 hours, the tall doors on the side of each coke oven are opened and the hot coke is pushed out of the oven by a huge mechanical arm and into a container for transportation, usually a rail car. The flaming hot coke is then quenched with either water or air to cool it before storage, or is transferred to the blast furnace for use in iron making.
Pollution generated by coke making is of substantial environmental concern.
The major sources of pollution are air releases of gases and particulate matter escaping from doors and lids, and air and water pollution from quenching operations. These releases often are accompanied by flames that increase the release of gases and particulate matter into the environment. The largest strides in pollution prevention for the iron and steel industry can be made by decreasing the need for coke, either in part or entirely. By eliminating the need for coke, the air emissions and solid wastes generated by coke making also are eliminated. Increased productivity, higher iron utilization, and greater energy efficiency are additional benefits.