Study On Different Driven Approach Of FeedWater Pump In Direct Air-cooling Unit

With the rapid development of national economy, China’s electricity consumptionincreases every year, and most of the current electricity comes from coal-fired powerplants. Direct air-cooling unit uses air as cooling medium, compared with conventionalwet cold power plant, it saves a lot of water resources, thus is widely used in coal-richregions. In order to further reduces the power cost of direct air-cooling power plant, thisessay studies on different driven approach of feedwater pump.This paper is based on600MW supercritical direct air cooled condenser. Themathematical model of condenser performance with the environment temperature, facevelocity, heat transfer coefficient and exhaust heat load is established. The linearrelationship between exhaust steam heat load and exhaust steam pressure under designconditions is also studied. On the other side, the thermal economy comparison scheme ofthe different driven approach of electric feedwater pump and steam feedwater pump isproposed. And the exhaust steam pressure of different driven approach is determinedaccording to the exhaust steam heat load of main condenser. On the basis of steamturbine theory and PowerBuilder program, the heat regenerative system parameters ofdifferent driven approach are obtained. Finally, the unit’s thermal economic indices canbe got according to the equivalent enthalpy drop method. The result shows that thescheme of steam feedwater pump with wet cooling tower has optimum economicindicators while taking standard coal consumption rate of power supply as the unitenergy consumption evaluation criteria.