Study On Condensing Heat Exchanger Of Gas-fired Boiler

With the optimization of energy structure, adjustment on the structure of energy sources of China, especially the implementation of changing coal to natural gas and energy-saving policy of big city like capital. So it is becoming more and more necessary for fields of international energy resources environment and engineering application department to development new technology equipments on high efficiently using natural gas.This paper aimed at developing condensing equipments for recycling thermal energy of flue gas of middle-small boiler research the key technology condensing equipments for recycling thermal energy of flue gas, based on previous study accumulation of our studying team and present manufacture mold and processing conditions, develop the prototype of condensing heat exchanger for 1 ton boiler, and put it into engineering application and monitor it, optimal scheme proposed on this foundation.Convection-condensation heat exchange of condensing heat exchanger both sides is selected for model building, FLUENT method is simulated of resistance flue gas side and water side of the condensing heat exchanger, rule of flowing obtained by simulating is compared with design data, that the simulated results anastomosed very well with the designing parameters, provide favorable reference for reasonably designing heat exchanger structure and further optimization.On the basis of previous study and measuring, mold reform is reformed and further optimized at low cost and draw out the drawings of 1 ton, the total copper amount reduces 8.2%, the total area of heat transfer increases 19.85%, and resistance on water side become one half, foundation is established for the optimization various series of gas-fired boiler.The measurement of condensing heat exchanger applied to the engineering shows that: the exhaust smoke temperature can be decreased from 170℃to 50℃, improve the boiler efficiency by about 9%, the thermal efficiency of boiler can reach up to 103% according to low heat of the gas. Best running condition obtained, returning water temperature and flue gas Re on thermal efficiency of condensing heat exchanger,and experimental correlation is summarized, all of these establish foundation for further optimizing similar equipments.If this is used just in Beijing boiler room calculated as the prototype, can save gas 2 billion m3/a, save 4 billion yuan/a fuel cost, generate 125 t/a condensed water and also reduce NOX 290 t/a, CO2 38.2 million t/a, social and economic Benefits is very huge.