Coke ovens and by-product plants

• Author: International Labour Organization
• Pages: 45-47

MEISI05-R-2005-02-0159-1-En.doc

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6. Coke ovens and by-product plants

6.1. Hazard description

6.1.1. Most coke is produced from coal. The coal is charged into an oven, which is

then sealed. A by product coke battery contains twenty or more tall, wide and narrow

ovens, arranged side by side like slices in a loaf of bread. After charging, a coke oven is

heated for 12 hours or more, during which time a variety of volatile chemicals are driven

off. In a by-product battery, these chemicals are collected and refined into a wide range of

products. The remaining coke oven gas is used as a fuel. In a non-recovery battery, the

ovens are typically low, broad structures, and the chemicals are burned in the headspace

above the coke or in the flues which heat the oven. Some new systems are under

development, but most involve similar hazards. Coke can also be produced from

petroleum.

6.1.2. Most health hazards in coke production arise from the volatile chemicals

driven off the coal during coking. Coke oven emissions contain cancer-causing

polynuclear aromatic hydrocarbons, along with toxic gases and vapours such as benzene,

hydrogen sulphide, carbon monoxide and ammonia. Workers in the coal preparation plant

are exposed to coal dust, which can cause lung damage. Coke ovens must be kept hot to

maintain their structural integrity, so production and maintenance operations pose the risk

of heat stress.

6.1.3. Safety hazards in coke production include mobile equipment, burns, fire and

explosion. Coke batteries are served by large tracked mobile equipment, including larry

cars used in charging, pusher machines used to remove the coke, and door machines used

to remove the oven doors when the coke is ready to be pushed. Visibility can be poor if

emissions are badly controlled, especially if the “coke side,” where hot coke is extracted, is

under a shed. Workers can suffer severe burns if they come into contact with hot coke,

doors or jambs, or if they step through a loose charging lid on the top of the battery. Coke

oven gas is flammable and explosive, as are many of the chemicals collected in by-product

plants.

6.2. Hazard control on by-product coke batteries

6.2.1. Coke oven doors, jambs and other equipment should be designed so as to

minimize the occurrence and magnitude of leaks.

6.2.2. Leaks from coke oven doors, lids, and other equipment should be eliminated or

reduced through a comprehensive operation and maintenance programme designed for that

purpose.

6.2.3. Leaking doors and jambs should be identified through a 24-hour inspection

programme, and repaired at the conclusion of the coking cycle. Other leaks should be

eliminated as soon as practicable.

6.2.4. Coke should not be pushed from the oven before the coking process is

complete.

6.2.5. Sealants for doors, lids and other equipment should be free of asbestos and

other hazardous materials.

6.2.6. Larry cars, pusher machines, door machines and similar equipment should be

operated from enclosed cabs equipped with filtered, conditioned air systems.