Numerical investigation and performance enhancement of 210 MW boiler by utilization of waste heat in flue gas

Abstract

The developing trend of increase in the price of fossil fuels forced the industries to find alternative energy sources and minimize heat loss. The utilization of waste heat in industries plays a pivot role to reduce the fuel consumption and emission of greenhouse gases. Overall it leads to a reduction in the cost of production. It is observed from the coal fired power plants, that the temperature of flue gas at the exit of the air preheater, which is the final regenerative device and, a proportionate amount of heat is carried away by way of the flue gases to the atmosphere. A substantial amount of fuel may be saved by way of utilizing the thermal energy from flue gas. Due to this saving, the performance of the boiler can also be increased considerably. A heat exchanger is used to extract the heat from flue gas to working fluid. The waste heat from the flue gas can be utilized to heat the feed water coming out from the condensate extraction pump. Feedwater gets heated once it gets into the heat exchanger. The heat exchanger is placed after the air preheater and it is analyzed in ANSYS 14.5 software. The effectiveness and efficiency of the heat exchanger is estimated to be 0.61 and 68.32% respectively. This heat exchanger could be used to save 6527.77$ in coal consumption by annually. This is accomplished through without traumatic the original machine in the power plant.