How Coke is Made
Sun Coke furnishes metallurgical coke to integrated steelmakers that utilize blast furnace technology. The company has served the steel industry for over 40 years and produces over 2.5 million tons of coke per year, 15% of total U.S. production, from its plants in Vansant, Virginia, East Chicago, Indiana, and Haverhill, Ohio. The recently constructed 1.8 million tons per year cokemaking facility and cogeneration power plant in Vitória, Brazil, became operational in early March 2007. But how is the coke made?
The process:
- A horizontal bed of coal (in a granulated form) approximately 3 feet deep, 12 feet wide and 42 feet long is loaded into the side of a hot oven (1,500° F at its coolest) using a leveling conveyor.
- The coal immediately absorbs heat from the surrounding refractory. Volatile matter in the coal is driven from the bed and burned, transferring heat from combustion back to the refractory.
- Partial combustion of volatiles occurs in the oven crown above the bed. Gases are then drawn into sole flues beneath the oven floor where more air is introduced to complete combustion and provide underfiring to the process. This allows the coal to form into chunks of coke about the size of a football or smaller.
- The gases then pass into an afterburner tunnel where any remaining uncombusted gases are oxidized.
- The afterburner tunnel system routes the hot gases to waste heat generators.
- Resulting steam can be used for process steam applications in various types of plants or for electrical power generation.
- The coke is pushed out and moved first to a quenching facility where it is cooled and then to an area where it is crushed and prepared for transport.
- Coke is shipped to customers by conveyor belt, by rail, and by barge. All coke leaving the Haverhill site will be shipped by rail car.
At the Haverhill coke plant, 47 tons of coke is loaded (charged) into each oven every 48 hours. Heat is neither gained or lost by the refractory (bricks that line the oven walls) over a normal coking cycle. This feature allows the Sun Coke oven to be a self-sustaining operation without any requirement for auxiliary fuel.
