A kind of system that improves superheater desuperheating water pressure
Technical field
The utility model relates to a kind of system that improves desuperheating water pressure, particularly relates to a kind of system that improves superheater desuperheating water pressure.
Background technology
Superheater spray desuperheating system is because of simple in structure, easy to operate, characteristics such as the temperature adjustment amplitude is big and inertia is little, thereby is used widely on modern boiler unit.The spray desuperheating system has become an important component part of power plant thermal system, and its project organization and method of temperature control directly influence the security and the economy of power plant's operation.Because the pressure that needs to the superheater spray desuperheating is very high, so must there be sufficiently high pressure at its water source, just sufficiently high pressure reduction, superheater spray desuperheating water is all taken from high-pressure feed water at present.
300MW level unit adopts governing feedwater pump, and when running on the lower load, the pressure reduction between superheater desuperheating water and the superheated steam reduces, the water spray insufficient pressure, and injection flow rate is very few and cause the accident of overtemperature of superheated vapor to take place.
The common technology scheme that addresses this problem at present has two kinds: a kind of is to install control valve on feedwater piping additional, when load descends, during the desuperheating water insufficient pressure, by turning down the aperture of control valve, improve the feedwater pump lift, thereby improve the pressure of desuperheating water, have enough pressure to spray in the boiler superheater, reach cool effect to guarantee desuperheating water; Another kind is on feed pump equipment booster stage to be set, the pressure of the desuperheating water that draw in the exit of booster stage all will be higher than the pressure of high-pressure feed water at any load condition, thereby guarantee that desuperheating water has enough pressure to spray in the boiler superheater when running on the lower load, reach cool effect.
On feedwater piping, install the scheme of control valve additional, the choke pressure drop of control valve is 1.0MPa ~ 1.5MPa, and the resistance of 0.3MPa ~ 0.4MPa is also arranged during the control valve standard-sized sheet, so big pressure drop, cause the power consumption of feed pump will increase by 1.5%, influenced the economy of power plant's operation.And the control valve price of scheme installing is very expensive, increases the power plant construction initial cost.The scheme of booster stage is set on feed pump equipment, when boiler superheater does not need to spray desuperheating water, can cause disturbance to the current in the feed pump, and increase the power consumption of feed pump, operation to feed pump has certain influence, and influences the economy of power plant's operation.
Summary of the invention
The purpose of this utility model is to provide a kind of system that improves superheater desuperheating water pressure.
The purpose of this utility model is implemented by following technical scheme, a kind of system that improves superheater desuperheating water pressure, it comprises high-pressure heater, described high-pressure heater outlet is connected by pipeline with boiler economizer, the feed pump outlet is connected with superheater direct-contact desuperheater inlet with described high-pressure heater inlet by pipeline respectively, and the pipeline that connects described feed pump outlet and described high-pressure heater inlet is provided with electronic quick throttle valve.
It comprises three described high-pressure heaters, and three described high-pressure heaters are connected in series by pipeline.
During normal the operation, electronic quick throttle valve standard-sized sheet is when load decline, during the desuperheating water insufficient pressure, by turning down electronic quick throttle valve opening, increase the resistance of feedwater piping, improve the feedwater pump lift, make electronic quick throttle valve front and back high-pressure feed water keep certain pressure reduction, thereby improve the pressure reduction between desuperheating water and the superheated steam, to guarantee that high-pressure feed water can have enough pressure to spray in the boiler superheater, reach cooling-down effect, guarantee safe operation of the boiler.The choke pressure drop of electronic quick throttle valve can be adjusted according to the pressure reduction between desuperheating water and the superheated steam when underload, and when normal operation was valve wide open, resistance was 0.05MPa.Still be normal operating condition no matter, adopt water supply system pressure drop that the quick throttle valve causes much smaller than adopting the water supply system pressure drop of transferring valve to cause at underload.
Advantage of the present utility model is, guaranteeing that the running on the lower load high-pressure feed water can have enough pressure to spray in the boiler superheater, reach under the prerequisite of cooling-down effect, reduced significantly and given water resistance, reduced the power consumption of feed pump, save station service, improved the economy of power plant, reduced initial cost greatly.
Description of drawings
Fig. 1 is 1 one kinds of schematic diagrames that improve the system of superheater desuperheating water pressure of embodiment.
Feed pump 1, electronic quick throttle valve 2, superheater direct-contact desuperheater 3, high-pressure heater 4, high-pressure heater 5 and high-pressure heater 6, boiler economizer 7.
The specific embodiment
Embodiment 1:A kind of system that improves superheater desuperheating water pressure, it comprises high-pressure heater 4, high-pressure heater 5 and the high-pressure heater 6 that is connected in series by pipeline successively, high-pressure heater 6 outlet and boiler economizer 7 are connected by pipeline, feed pump 1 outlet is connected with superheater direct-contact desuperheater 3 inlets with high-pressure heater 4 inlets by pipeline respectively, and 1 outlet of connection feed pump is provided with electronic quick throttle valve 2 with the pipeline of high-pressure heater 4 inlets.