A coke oven battery is a group of ovens in which coal is heated to extremely high temperatures in the absence of air. This process concentrates the carbon in the coal to produce coke.
Coal is processed into coke in large batteries of ovens before entering a blast furnace. The carbon in coke is more concentrated, making it more efficient than coal. Before carbonization, coal is blended, pulverized and oiled to ensure proper density. The resulting coke is used to reduce the amount of iron in blast furnaces.
Inside the coke oven battery, coal is heated to 2012 degrees Fahrenheit in order to drive out volatile compounds. Each oven in the battery shares a common heating flu with the adjacent oven. The result is coke, which is hard but porous, and has more concentrated carbon than coal.
In the United States, most of the coke produced comes from byproduct coke oven batteries. In these coke oven batteries, the compounds burned off by the heating process are recovered and reused.
In non-recovery coal production, coke oven batteries heat the coal, and the combusted gases escape through a stack. This creates a natural draft in the oven. These were originally referred to as beehive ovens.