DESIGN AND ANALYSIS OF AIR PREHEATER

Air preheater is one of the accessories of steam generators, that works as a heat exchanger that utilizes the heat of the flue gas of the boiler, heating the air needed for the combustion of the fuel, thereby increasing the thermal efficiency of the boiler. It makes a considerable contribution to improve the overall efficiency of fossil-fuel-fired power plants. The paper presents the design of a Recuperative Tubular type, air-through-air Preheater with the staggered tube arrangement, designed to meet specific performance requirements, using the software application SOLIDWORKS. An analytical study was undertaken and various heat transfer performance parameters like outlet temperature of the air, inside and outside heat transfer coefficients, overall heat transfer coefficient and rate of heat transfer involving conduction and convection modes of heat transfer were found. The results were tabulated and graphically depicted. These results were validated using CFD analysis at 100% load and were found to be in good agreement with each other, with very little deviation. These heat transfer parameters are critical in the designing and functioning of Air Preheater to get the desired output. Air flow phenomenon, flue gas flow phenomena, temperature distribution and pressure drop in the Air Preheater were discussed in the CFD analysis.