coke oven[′kōk ‚əv·ən]
an industrial unit for coking pit coal. The first coke ovens (”stall” ovens) were used in the early 19th century. They consisted of brick walls 1.5 m high, up to 15 m long, and 2–2.5 m apart. Coal was loaded into the space between the walls, covered with earth on the top and ends, and ignited. Coking lasted eight to ten days. Beehive ovens began to be used in the 1830’s. In this case, coking was performed in closed domed chambers, with limited access of air. Flame ovens with external heating began to be used in the mid-19th century. The coal charge was loaded into chambers lined with firebrick and separated by heating spaces with vertical channels in which coke-oven gas was burned. An important development during the 1870’s involved the recovery of chemicals from coke-oven gas. The coking chambers in the ovens were separated from the heating channels.
Modern coking ovens are divided into horizontal and vertical types, according to the method of charging the coal. Horizontal batch-type coke ovens are the most widespread units. They consist of a coking chamber, heating ducts located on both sides of the chamber, and regenerators. The upper part of the chamber contains loading hatches, and the ends of the chamber are closed by removable doors. The chambers may be up to 13–16 m long, 4–7 m high, and 0.4–0.5 m wide. The chamber is heated by combustion of coke-oven, blast-furnace, or other gases in the vertical channels. The coking cycle of a single coal charge (usually 13–18 hours) depends on the chamber width and the temperature of the heating duct. When coking is complete, the red-hot coke is pushed out of the chamber through the door openings by the coke pusher and is quenched. To make the coking plant more compact and to achieve better use of the heat, coke ovens are combined into groups (61–77 ovens each), with common systems for supplying heating gas and coal and for the discharge of coke-oven gas. All operations concerning servicing of the coke oven (loading, unloading, opening and closing of the doors and hatches, and pushing out and quenching of the coke) are mechanized and automated. Continuous coking ovens, such as the vertical and circular types, are being developed.
D. A. KOPANEVA