Economizer 
 Rear of the boiler flue economizer that will heat the boiler feed water into the drum pressure saturated water heating surface, because it is relatively low absorption of the flue gas, reducing the flue gas exhaust gas temperature, saving energy, improve efficiency, so called economizer. 
 Economizer in the boiler used to heat boiler feed water; role are: to reduce exhaust gas temperature, increase boiler efficiency; to drum stress reduction; to reduce the economizer heating surface of boiler replacement cost of evaporation; reduce the boiler temperature difference, reduce the losses of cold source 
 The role of economizer two. The first role is to raise water temperature, can also produce a small amount of boiling steam economizer. Into the water from the deaerator economizers, low oxygen water temperature is generally 104 ℃, high temperature of deaerator about 158 ??℃. Medium pressure boiler (4.4Mpa) the saturation temperature is about 256 ℃, high-pressure boiler (11 Mpa) in the saturation temperature of 317 ℃, high temperature is much more than oxygen. If there is no economizer, water directly into the drum, then drop the tube into the water due to heat too much, a large part of water wall heating surface used to raise water temperature, and used to generate steam heating surface reduced evaporation of the boiler was reduced. After installation of the economizer, can significantly increase the water temperature. For the boiling Economizer, water temperature can be raised to the saturation temperature under the pressure of the boiler and steam to produce a small amount (about 10% of the boiler evaporation to 20%). Into the water wall to absorb heat when the water, you can vaporization, evaporation of the boiler was significantly increased. 
 The second effect is to lower the gas temperature, flue gas heat recovery, improve boiler thermal efficiency, save fuel. Superheater exit gas temperature is about 700 ℃, even after the layout of a large number of convective superheater tubes, boiler water temperature due to pressure saturated steam drum temperature, the temperature of flue gas to leave the convection tubes are still as high as 250 ~ 350 ℃, the flue gas also contains a lot of heat. Or convection superheater tubes in the post-install economizer, flue gas temperature can effectively reduce, recycle a lot of heat, save a lot of fuel, because the early coal-fired boiler is usually, so called economizer. 
 After installing the boiler economizer into the drum of water temperature greatly increased. Economizer for boiling, the water temperature into the drum of the drum is the saturation temperature under pressure, is for non-boiling type economizer into the drum temperature does not exceed the water supply but also close to the saturation temperature. Therefore, the water heated by the economizer, because the water temperature is equal or close to the saturation temperature of steam drum pressure, can reduce the thermal stress caused by temperature difference and improve the working conditions of the drum. 
 Steel Economizer not pressure limits can be used as boiling type, generally 32 to 51 mm diameter carbon steel pipes. Sometimes the tube plus fin and fin to improve heat transfer. Steel Economizer parallel arrangement by the level of elbow tube (often called serpentine tube) formed 
 Economizer function: 
 1, the absorption of low-temperature flue gas heat, reduce exhaust gas temperature, reduce exhaust losses and save fuel. 
 2, the water supply into the drum before the economizer heating, thus reducing the heat-absorbing water in the heating surface can be used to replace part of the economizer high cost of heating surface evaporation. 
 3, the water temperature has increased, is reduced into the drum wall temperature, thermal stress is reduced accordingly, to extend the drum life. 
 4, the economizer recirculation role: 
 In the boiler (drum boiler) in the startup process, because of its soft drinks do not build the pipeline cycle, the boiler feed water at a standstill, this time in non-economizer flow of water within the state, along with the strengthening of combustion, smoke increased temperature, economizer prone to vaporization of the water, so that the local is in over-temperature economizer state. To avoid this situation, and from the water pipes draw a line under the drum of concentrate to the economizer of a pipeline entrance, as the recycling pipeline, so that the water in the economizer flow state. avoid vaporization. 

 Energy Equipment Co., Ltd. Tianjin Xinhua