Research On Energy Saving Transformation Of Back Pressure In 600MW Direct Air Cooling Unit

In northern China,the phenomenon of water shortage is widespread.In order to reduce the waste of water resources,direct air cooling has been adopted more and more widely.However,since the air-cooling medium of the direct air-cooled heat exchanger is air,its heat exchange performance is unavoidably affected by natural conditions such as ambient temperature,wind speed and pressure.The heat transfer performance of the direct cooling system directly affects the economy of the unit operation.The back pressure fluctuation is closely related to the operation safety of the unit.Therefore,analyzing the influencing factors of the heat exchange performance of the direct air cooling system and making reasonable modifications to improve the heat exchange capacity appears very important.In this paper,by examining the terrain condition of a power plant,we know that the plant air-cooled island is located between the peaks on both sides and is affected by canyon wind all the year round,together with the high summer ambient temperature,which adversely affects the back pressure of the unit.Due to the sand blown by the canyon wind all the year round and various impurities,the heat exchanger tube forms a certain degree of scale formation,which directly leads to the air-cooled heat exchanger performance decreasing year by year.Therefore,in this paper,the direct air-cooled island and the peaks on both sides of the plant are modeled firstly.The cause of high backpressure in the unit is analyzed by numerical simulation and the influence on the heat transfer capacity of direct air-cooling when the change of ambient wind speed is explored.In view of the fact that the ambient wind affects the heat transfer performance of the air-cooled island and causes a high back pressure,a new type of air-cooling system is proposed in combination with the strong ability of anti-natural change of the indirect air-cooling unit and the small heat transfer margin of the jet condenser.In this way,the original direct cooling system is retrofitted to reduce the back pressure,and calculate the back pressure drop before and after the reconstruction at the time.Finally,the conclusion and the prospect of the full text are summarized.