In order to improve the thermal efficiency of the industrial gas steam boiler in the whole power plant, the industrial gas steam boiler in the power plant is equipped with a feed water heater. The heater before the feed pump is called a low pressure heater and the one after the feed pump is called a high pressure heater. After the feed water is fed by the high pressure heater, the feed water temperature is greatly increased. For example, the feed water temperature of medium pressure industrial gas steam boiler is mostly heated to 172 ��, and the high pressure furnace is generally heated to 215 ��.
During the operation, due to the leakage of high-pressure heater, the feedwater is supplied to the industrial gas steam boiler by the bypass when the high-pressure heater is disconnected. After the water supply temperature of the industrial gas steam boiler is reduced, a part of the heat in the fuel is to be used to increase the feed water temperature. If the evaporation amount is kept constant, the amount of fuel is increased, and the flue gas temperature and the flue gas flow rate of the furnace outlet are increased, and the heat absorption of the superheater is increased, and the steam temperature is necessarily increased. After the water supply temperature is reduced, it is assumed that the amount of fuel does not change, the amount of heat in the fuel is used to increase the feed water temperature, the amount of heat used to evaporate the generated steam is reduced, and at this time, due to the change in the combustion condition, the furnace The flue gas temperature and flue gas velocity at the outlet of the chamber are not changed, and the heat absorption of the superheater is not reduced. But due to the reduced evaporation, the steam temperature is necessarily increased. So the water supply temperature is reduced and the steam temperature is necessarily increased.
