Design and Thermal Analysis of Heat Exchanger for Energy Conservation

Energy conservation has become an area of immense importance in the present era of fast depletion of fossil fuel. Study of exhaust emissions and their control is also equally important because of global worming concerns. This paper discusses the recovery of waste heat from the hot flue gases in thermal power plants and usage of the same to preheat a part of the condensate to improve the cycle efficiency. Thereby it results in substantial cost reduction as well as decrease in the emissions of various pollutants. This can be achieved by designing a shell and finned tube heat exchanger placed into the flue gas duct between ID fan and chimney. A part of the condensate is heated in this heat exchanger, while the flue gases are cooled to an acceptable lower temperature. The dew point of S02 on moisture content of coal and relative humidity of air was studied. The effect of different baffle cuts and tube pitches of heat exchanger have been investigated. The heat exchanger is designed for minimum pressure drop on water and flue gas side and by improving the plant cycle efficiency and observed that about 6 percent energy is conserved