Application Of Direct Evaporative Cooling Technology In Energy-saving Of Boiler System Of Thermal Power Plant

Aiming at the problem of effect on load resulting from lack of air for combustion in boiler of thermal power plant in summer, the research of the application technology concerned is made in this thesis. A method that direct evaporative cooling technology is adopted to cool the air supply of boiler in order to increase the air density and the oxygen concentration in air supply is presented to solve the problem.In this thesis, the energy-saving technology of boiler and forced draft fan is introduced. The principle, the applied field, the equipment developed and the status in quo of research of the evaporative cooling technology is also introduced. The CFD software FLUENT is used to simulate the temperature, pressure and velocity distribution in boiler room. By analyzing the change of the meteorologic and air supply state parameter of whole year, the extent of change of the air density and the oxygen concentration in air supply after evaporative cooling is obtained. The process of the heat and mass transfer of membrane direct evaporative cooling is analyzed in thermodynamics and the mathematical model of cross-flow direct evaporative cooler is established. According to the existent equipment in laboratory, the test-bed of direct evaporative cooling using packing material on which the water is sprinkled is set up. Meanwhile, the test device and instrument concerned is introduced and the project of the orthogonal test is planed. The performance parameter of the direct evaporative cooler is obtained in different test condition by testing actually. The original data measured is analyzed and used to make charts by special software and then the effect of each factor on the performance of the direct evaporative cooler is summed up.Finally, in connection with an actual case, the applied effect of reconstruction of air supply system of boiler of thermal power plant by direct evaporative cooling technology is analyzed in detail. And the energy-saving and economical analysis of the thermodynamic performance and air supply system of boiler after reconstruction is concerned. Through the theoretical calculation, after reconstruction, the temperature of air supply is decreased and the air density and oxygen concentration in air supply is increased, which can satisfy the oxygen supply for combustion in hearth. Consequently, the reconstruction is able to solve the problem of lack of air for combustion in boiler in summer and realize the energy-saving. By absorbing the heat emitted from boiler surface, the energy can be recycled. Meanwhile, the air quality of boiler room is improved.