Grate firing
Encyclopedia
Grate firing was the first combustion
system
used for solid fuel
s. It now is used mainly for burning waste
and biomass
, but also for smaller coal
furnaces.
Reciprocating grate
Vibrating grate
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
system
System
System is a set of interacting or interdependent components forming an integrated whole....
used for solid fuel
Solid fuel
Solid fuel refers to various types of solid material that are used as fuel to produce energy and provide heating, usually released through combustion....
s. It now is used mainly for burning waste
Waste
Waste is unwanted or useless materials. In biology, waste is any of the many unwanted substances or toxins that are expelled from living organisms, metabolic waste; such as urea, sweat or feces. Litter is waste which has been disposed of improperly...
and biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
, but also for smaller coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
furnaces.
- Capacities 0.3 to 175 MWth in industry and CHP
- Fuel fired per grate area 1-2 MW/m2, maximum grate area 100 m2
- Grates are typical only suitable for coarse particles, for fine particles a spreader is required, increases max. capacity
- Primary air through the grate (also used for cooling) and secondary air
Types
;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.
See also
- fluidised bed firing
- pulverized fuel firing