Coke oven plants are large and expensive. They take coal of certain types and heat it in chambers at temperatures in excess of 1000 degrees centigrade in the absence of air. This meanns the product does not combust. Chemicals and water are driven off leaving a mass of carbon with a little ash. This is pushed out of the chamber, quenched with water and, when dry, sent for use, often to blast furnaces, where it provides the fuel for heat and the refduvcing gas, Carbon Monoxide, which removes the oxygen from iron ore leaving iron and slag.
The chemicals are separated and sold into other indusstries. Many products come from coal.
This plant is almost 40 years old and near closing. There should be no smoke or flame visible from the structure and pushed coke should not show heavy smoke.