A coke oven plant is a facility that produces coke, a type of fuel that is derived from coal by heating it in an oxygen-free environment. Coke is mainly used as a reducing agent and a source of heat in the blast furnace process of ironmaking. In addition to coke, the coke oven plant also produces by-products such as coke oven gas, tar, ammonia, benzene and other chemicals.
The operation of a coke oven plant involves several steps. The main steps are:
Coal handling:
The coal is delivered to the coke oven plant and stored in a coal yard. The coal is then crushed and blended to achieve a suitable quality and size for coking. The coal blend is transferred to a coal tower, where it is charged into a Larry car. The Larry car travels along the top of the coke oven battery and feeds the coal into the ovens through charging holes.
Coking:
The coal is heated in the coke ovens at a temperature of about 1100°C for 16 to 20 hours. During this process, the volatile matter in the coal is driven off as coke oven gas, and the fixed carbon remains as coke. The coke oven gas is collected and sent to the by-product plant for treatment and recovery of valuable chemicals. The coke ovens are sealed with refractory bricks and lids to prevent air ingress and gas leakage.
Coke pushing:
After the coking cycle is completed, the coke is pushed out of the oven by a ram car or a pusher machine. The hot coke falls into a quench car, which transports it to the quenching tower.
Coke quenching:
The hot Coke is quenched with water or inert gas to cool it down and stabilize its physical properties. The quenched coke is then discharged from the quench car onto a wharf or a conveyor belt.
Coke screening:
The Coke is screened and sorted into different sizes according to the requirements of the blast furnace or other customers. The smaller fractions of coke are used for sintering or as nut coke. The larger fractions of coke are known as blast furnace coke.
By-product recovery:
The coke oven gas that is generated during coking contains various chemicals such as tar, ammonia, benzene, naphthalene, hydrogen sulfide, carbon monoxide and others. These chemicals are recovered and purified in the by-product plant using various processes such as condensation, absorption, distillation and scrubbing. The clean Coke oven gas is then used as fuel for heating purposes in the plant or sold to external customers.
The operation of a coke oven plant requires careful control and monitoring of various parameters such as temperature, pressure, gas composition, coal quality, coke quality and environmental emissions. The operation also involves various safety hazards such as fire, explosion, gas poisoning, dust exposure and heat stress. Therefore, proper safety measures and precautions are necessary to ensure the safe and efficient operation of the coke oven plant.
