Grate firing

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Grate firing was the first combustion system used for solid fuels. It now is used mainly for burning waste and biomass, but also for smaller coal furnaces.

Combustion high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized in a mixture termed as smoke

Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion in a fire produces a flame, and the heat produced can make combustion self-sustaining. Combustion is often a complicated sequence of elementary radical reactions. Solid fuels, such as wood and coal, first undergo endothermic pyrolysis to produce gaseous fuels whose combustion then supplies the heat required to produce more of them. Combustion is often hot enough that incandescent light in the form of either glowing or a flame is produced. A simple example can be seen in the combustion of hydrogen and oxygen into water vapor, a reaction commonly used to fuel rocket engines. This reaction releases 242 kJ/mol of heat and reduces the enthalpy accordingly :

A system is a group of interacting or interrelated entities that form a unified whole. A system is delineated by its spatial and temporal boundaries, surrounded and influenced by its environment, described by its structure and purpose and expressed in its functioning.

Solid fuel solid material that can be burnt to release energy

Solid fuel refers to various forms of solid material that can be burnt to release energy, providing heat and light through the process of combustion. Solid fuels can be contrasted with liquid fuels and gaseous fuels. Common examples of solid fuels include wood, charcoal, peat, coal, Hexamine fuel tablets, wood pellets, corn, wheat, rye, and other grains. Solid fuels are extensively used in rocketry as solid propellants. Solid fuels have been used throughout human history to create fire and solid fuel is still in widespread use throughout the world in the present day.

Contents

Types

travelling grate in an old steam boiler 1-wanderrost-kohlekessel travelling grate.JPG
travelling grate in an old steam boiler
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.

See also

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