Research On Optimizing Design Method Of Dry And Wet Cooling System In Thermal Power Plant

The dry and wet cooling system is the major trend of cooling system in coal-fired plant. The initial temperature difference (ITD) of the dry and wet cooling tower is the main factor which affects the safety and economy of the dry and wet cooling unit, furthermore, it's also an important parameter in the cold-end design for air cooling unit. As we know, the optimization design plays an important role in improving the economy of dry and wet cooling system.In this paper, the cooling system in thermal power plant is discussed, and the features and varieties are introduced. Then air-cooled dry and wet combination units are analyzed, aiming to the features of the air cooling system and wet cooling system. The optimization theory of the dry and wet combination units and optimization calculation of the dry and wet cooling power are the main content. The heat quantity of the air cooling system and wet cooling system has been distributed rationally, aiming to the features of the no fully weight in summer operating in thermal power plant. As an example, the ITD value of a 300MW dry and wet cooling system in certain place is optimized by taking the average annual costs of dry and wet cooling system as objective function,converted the invest costs and orbit costs in service fixed number of years,and a satisfied effect is reached. The cooling tower is an important accessory equipment of a thermal power plant which has great effect on safe and economical operating. Besides, the optimizing design for the dimension of the dry and wet cooling tower is a part of optimizing design for the cooling system. A comprehensive analysis on optimizing the dimension of the dry and wet cooling tower is given, the optimizing design is also optimized by taking the average annual costs of dry and wet cooling system as objective function, furthermore, this method is illustrated with a practical application and a satisfied result is also reached. Moreover, sensitivity analysis is given, and the relation curves of the average annual costs and the ITD value are got under different ambient air temperature, different cost of generate electricity and different price of cooling triangle.As mentioned in this paper, the optimal design method for dry and wet cooling system is valueful for the design and operation of cooling system at different economic and meteorological conditions, and have practical significance for promoting combined cooling units development.