Grate firing

Grate firing is a type of industrial combustion system used for solid fuels. It now is used mainly for burning waste and biomass, but also for smaller coal furnaces.

Types

travelling grate in an old steam boiler

Until the 1930s, the Dutch oven was the primary technology used to improve combustion for low-quality or high-moisture fuels. It has largely been replaced by the following:

Travelling grate
A moving grate which is covered with a fuel layer, 10-30 cm. Power control by means of varying the grate velocity
Reciprocating grate
For ash-rich, low calorific fuels like municipal waste, arrangement of stationary and moving grates -> conveying and mixing (forward-moving type or reverse-action grate)
Vibrating grate
Water cooled membrane wall, with holes for air. For burning coal or wood.

Grate area

The grate area is the area of the grate (length x width). The larger the grate area, the more fuel can be burned per hour. The amount of fuel burned also depends on the fuel or bed movement velocity.

References

  1. ↑ EN 12952-16:2022 Water-tube boilers and auxiliary installations – Part 16: Requirements for grate and fluidized-bed firing systems for solid fuels for the boiler. European Committee for Standardization (CEN). EN 12952. Brussels: CEN. 2022.
  2. ↑ Petchers, Neil (2012). Combined Heating, Cooling & Power Handbook: Technologies & Applications. New York: Routledge. p. 108. ISBN 9788770229135.

See also