Abstract: [Objectives] In order to solve the problem of high energy consumption of 330MW coal-fired thermal power generation units, this study proposes an optimization method for cold-end system based on mathematical modeling. Through the reasonable configuration of circulating water pump and cooling fan, the vacuum degree of the condenser is accurately adjusted to improve the efficiency of the unit. [Methods] Taking a 330MW closed-circuit unit of a power plant as the object, the optimization model was constructed based on the total heat transfer coefficient method and enthalpy difference method proposed by the Heat Exchange Institute (HEI). The operation combination under different load conditions was simulated and calculated, and the optimal parameter configuration was determined, including the number of pumps and fans turned on and the vacuum degree of the condenser, and the accuracy of the model was verified by using the actual data. [Results]The performance of the cooling-end system is significantly improved after optimization: the cooling water temperature of the cooling tower is reduced by 26.38%, the cooling water temperature of the incoming tower is reduced by 22.12%, the vacuum degree of the condenser is increased by 1.57%, and the net output power is increased by 0.3%. These improvements effectively reduce cooling water temperature, reduce energy and coal consumption, and improve thermal efficiency and power generation capacity. [Conclusions] This method solves the problems of low efficiency and high energy consumption in the traditional mode, reduces fuel consumption and operating costs, prolongs the life of equipment, achieves a win-win situation of economic and environmental benefits, provides a new path for energy conservation and emission reduction of coal-fired units, and promotes the sustainable development of the power industry.

Key words: steam turbine vacuum, energy savingof cooling towers, energy conservation and emission reduction, mathematical modeling, Intelligent optimization