Coal Stoker Refractory Specifications

A coal stoker refractory operates as an automatic coal burner that feeds coal into the fire at a specifically set rate. As a result, they require less monitoring. They are also able to function continuously, as long as the coal is kept in supply and the resulting ash debris is regularly cleared. Coal stokers have a range of household uses, including stoves, furnaces and boilers, as well as industrial applications such as power stations.

Components

• The average coal stoker refractory is comprised of several components. These include a furnace chamber, a boiler or other heat source, a feeder, a ventilation air system, a collection hopper and a rotating metal grate bar floor that transports the coal along the furnace chamber towards the heat source.

Categories

• Coal stokers vary according to the rate at which coal is burned. They are categorized into four classes. Class 1 stokers burn between 4.5 to 45 kilograms of coal per hour. Class 2 stokers burn from 45 to 135 kilograms each hour.Class 3 uses between 135 and 540 kilograms per hour. Class 4 stokers burn over 540 kilograms every hour.

Coals

• The size of coals used is approximated between three-quarters of an inch and one-and-a-quarter inches. When using bituminous coal, the optimum ash fusion temperature ranges between 2200 degrees and 2600 degrees Fahrenheit. Coals are treated with oil to limit the amount of dust produced, however, excess oil creates wet coal, resulting in poor combustion.

Operation

• Feeders found at the front of the boiler places coal to the back of the furnace. A ventilation fan located beneath the floor allows combustion air into the furnace chamber. This enables some coal to burn while in transit, a process called suspension burning. The burnt ash falls off as the rotating floor reaches the front of the boiler, and is collected in the collecting hopper. The cycle then repeats itself.