Incomplete combustion of solids has the greatest loss.
Heat loss includes: smoke loss;Heat loss of incomplete combustion of gas;Heat loss from incomplete combustion of solids;Heat loss;Ash physical heat loss.
The heat loss of boiler is mainly as follows:
1. Heat loss from smoke extraction
Industrial boilers smoke exhaust temperature is higher, in 200 ~ 300 degrees, such a high smoke exhaust temperature, it means more part of the fuel heat is taken away by the smoke in the atmosphere, resulting in the boiler smoke exhaust heat loss.The higher the exhaust temperature, the more the exhaust heat is lost.Generally, the heat loss of smoke extraction can be reduced by about 1% when the smoke extraction temperature decreases by 15 ~ 20 degrees.
In order to reduce the heat loss of smoke exhaust, it is often used to increase the heating surface of the tail, such as increasing the coal economizer and air preheater, but can not reduce the smoke exhaust temperature too much, otherwise it will cause the boiler metal consumption increased more and the possibility of low temperature corrosion of the heating surface of the tail increased.In addition, when the boiler is running, it can reduce the heat loss of exhaust smoke through constant ash, controlling excess air coefficient and reducing air leakage in various parts of the flue.
2. Incomplete combustion
In the flue gas contains a part of combustible gas in the furnace does not achieve complete combustion, but with the flue gas emissions, this part of the heat loss is called gas incomplete combustion heat loss.The furnace size is too small, the height is not enough and so on will cause the combustible gas to enter the low temperature flue without enough time to burn and cause the gas incomplete combustion heat loss.Adding secondary air to the boiler can enhance the mixing of air and combustible gas and promote complete combustion.
3.Incomplete combustion of solids
In the combustion process of solid fuel, there is always a part of fuel that does not burn but leaves the boiler with ash or fly ash. This part of heat loss is called heat loss of incomplete solid combustion.For solid fuel boilers, the heat loss from incomplete combustion of solid is the main heat loss in the total heat loss.The more ash there is, the more fuel is trapped in the ash, and the greater the heat loss.
4. Heat loss
During boiler operation, the temperature of furnace wall and boiler body is always higher than the temperature of surrounding air, which will cause heat loss and heat dissipation.The heat loss is related to the boiler's external area, adiabatic degree, ambient air temperature and air flow velocity.General requirements of the furnace wall surface temperature should not exceed 50 degrees.
