Research On The Calculating Method Of The Optimum Vacuum Of Double Back Pressure Condenser

As an auxiliary equipment of the steam turbine, condenser has material effect on operationperformance of steam turbine. Recently the condensing turbine that is put into operationmatched with the double back pressure condenser or multi-pressure condenser mostly. Thecondenser’s structure which compares to single-pressure condenser is different, thecorresponding parameters are also different, thus in the calculation of optimum vacuum of thecondenser should also have differences.In purpose of calculating the optimum vacuum of double back pressure condenser，firstly,this paper programs to determine the exhaust steam pressure of double back pressurecondenser, according to the calculation of the general curve for steam turbine electric powerchange of the steam turbine can be got from exhaust steam pressure change. Then consideringcooling water pump’s working condition and cooling water costs to calculate the optimumvacuum of condenser. The purpose of this research is to calculate the optimum vacuum ofdouble back pressure condenser to get close to the optimization of the cooling water system,content of this research is divided into the following three parts.First of all, according to structure characteristics of double back pressure condenser, heattransfer characteristics are analyzed. The single-pressure condenser is compared, and it pointsout the superiorities.Second, in order to predict the steam turbine power with the change of pressure changedegree, it take advantage of the steam turbine general curve that based on the using of the testdata to draw, the process of multiple theoretical calculation methods such as equivalententhalpy drop method, steam turbine method are compared.Finally, on this basis, consider water-saving factor to calculate the optimum vacuum ofdouble back pressure condenser, by changing the traditional definition of the optimumvacuum this can be more economic to get the purpose of optimizing the cooling water system.Through the optimized calculation of water circulating system in the actual plant units, it getthe optimization of pumps’ combinations which consider the factor of cooling water costs and with the condition of not consider factor of cooling water costs to compare.