| This paper took the cold end gas extraction system of 330MW power units of Guohua Huizhou Power station as the study object. It studied the influence of back pressure variation on plant unit power. It proposed a method of determining the maximum condenser vacuum, so it lay the foundation for optimizing of the working water temperature of the water ring vacuum pump. Analysis of vacuum performance and to amend under different operating conditions, get the actual pump performance curve; Proposed the critical temperature of the working water ,and determining the method of critical temperature; Analysis of influence on the accumulation in condenser under different water temperature, The establishment of the mathematical model of influence on condenser heat transfer coefficient and pressure; Work on the water temperature often is higher than the critical temperature, so proposed to auxiliary cooling system, achieving the optimal operation of the water temperature. |