Why is the thermal efficiency of the boiler greater than 100%?
2021-12-29 14:46:05
First of all, we must first know what is the high calorific value and low calorific value of fuel?
Fuel calorific value is divided into high calorific value and low calorific value.
High calorific value: all the heat released when the fuel is completely burned, including the latent heat of vaporization released by the water vapor in the flue gas that has condensed into water.
Low calorific value: deduct the latent heat of vaporization of water vapor in the flue gas from the high calorific value of the fuel.
High calorific value = low calorific value + latent heat of vaporization of water vapor
The low calorific value is the closest to the actual calorific value of an industrial boiler during combustion, and is often used in design calculations. That is to say, the efficiency of the original boiler does not consider the part of the latent heat of gasification that accounts for 11% of the exhaust gas. The thermal efficiency of the general boiler is 90 ~92%.
Therefore, when calculating the boiler efficiency based on the low calorific value, if the condensation technology is used to utilize the latent heat of vaporization and part of the sensible heat in the exhaust gas, the efficiency may be greater than 100%.
Fuel calorific value is divided into high calorific value and low calorific value.
High calorific value: all the heat released when the fuel is completely burned, including the latent heat of vaporization released by the water vapor in the flue gas that has condensed into water.
Low calorific value: deduct the latent heat of vaporization of water vapor in the flue gas from the high calorific value of the fuel.
High calorific value = low calorific value + latent heat of vaporization of water vapor
The low calorific value is the closest to the actual calorific value of an industrial boiler during combustion, and is often used in design calculations. That is to say, the efficiency of the original boiler does not consider the part of the latent heat of gasification that accounts for 11% of the exhaust gas. The thermal efficiency of the general boiler is 90 ~92%.
Therefore, when calculating the boiler efficiency based on the low calorific value, if the condensation technology is used to utilize the latent heat of vaporization and part of the sensible heat in the exhaust gas, the efficiency may be greater than 100%.
Consultation
