The important effect of economizer:
The first effect is to raise water temperature, boiling economizer can also produce a small amount of steam. Enter the water supply from the deaerator economizer, low pressure deaerator water temperature is 104 ℃, high-pressure oxygen the water temperature of about 158 ℃. MV furnace (4.4Mpa) saturation temperature of about 256 ℃, high-pressure furnace (11 Mpa) saturation temperature of 317 ℃, a much higher temperature than oxygen. If no economizer, water directly into the drum, since less water into the drop tube heat too, a large part of the heating surface water wall to raise the water temperature, which is used to generate steam to reduce the heating surface of the evaporator boiler the amount is reduced. After installing economizer, can significantly raise the water temperature. For boiling economizer can raise the water temperature to the saturation temperature of the boiler pressure and steam to produce a small amount (about 10% to 20% of the amount of evaporation of the boiler). Wall after the water absorbs heat, can be vaporized evaporation boiler significantly improved.
The second effect is to reduce the flue gas temperature, flue gas heat recovery, improve boiler thermal efficiency and save fuel. Superheater outlet flue gas temperature of about 700 ℃, even after a lot of convection superheater tubes arranged, boiler water temperature due to the saturation temperature of the steam drum pressure, the temperature of the flue gas leaving the convection bank is still up to 250 ~ 350 ℃, the flue gas is also It contains a lot of calories. After installation of the superheater or economizer convection bank can effectively reduce the flue gas temperature, a lot of heat recovery, save a lot of fuel, due to the early coal-fired boilers are generally, so called economizer.