The use of desuperheating water for extraction steam has a certain influence on thermal performance of the units

but the research on this aspect is relatively less. Taking a 330 MW cogeneration unit as an example

two schemes of extraction steam desuperheating with desuperheating water intake located at the outlet of condensate pump(scheme 1) and the place between No. 6 and No. 7 low pressure heaters(scheme 2) are compared by using the software EBSILON. The results show that

no matter the temperature of desuperheating water is high or low

as long as the desuperheating water is used

the coal consumption rate of the unit will increase

but the increment of coal consumption rate can be reduced by using desuperheating water with higher temperature. Under the rated condition

the increase of coal consumption rate of scheme 2 is 52.1% lower than that of scheme 1. At the same time

the temperature of desuperheating water also has an effect on the increase of extraction steam at the same heating load. In addition

both the flow rate of desuperheating water and the increment of coal consumption rate increase at first and then decrease with the increase of heating load at a certain live steam flow rate. When the desuperheating water is used

the system analysis should be carried out. By selecting the desuperheating water reasonably

the daily operation load of the unit can effectively avoid the area with the largest coal consumption rate increment.