Combined Heat Exchange And Dust Removal Technology For Utilization Of The Low-temperature Flue Gases Waste Heat

With the rapid development of economy, the energy demand is increasing surprisingly inChina．Energy short supply has been one of the principal elements restricting the development ofeconomy and society．In industrial processes，almost50％of thermal energy transforms intolow-grade waste heat discharged directly, which leads to energy waste and environmentalpollution．How to recover and use of this part of the low-grade thermal energy has importantpractical significance with energy saving.The thesis main research recovery and utilization of flue gas waste heat by fin-tube heatexchanger. The heat transfer performance and dust properties of the heat exchanger were studiedby using the numerical simulation method.The main contents and conclusions are as following：1. For uniform annular fin, it was difficult to obtain analytical solution of the temperaturedistribution on the fin, using curve fitting method to solve differential equations, the calculationwill be simple and small errors. based on the same metal consumption, the optimal structure ofuniform annular fin: fin height13mm, fin thickness0.74mm, the heat transfer94W, finefficiency83%; based on the same heat transfer (90W) of a single fin, the optimal structure ofuniform annular fin: fin height12.5mm, fin thickness0.71mm, fin efficiency84%.2. Establishing mathematical model for fin-tube heat exchanger, and using Visual C++tosolve heat transfer coefficient, heat transfer and thermal resistance factor of heat exchanger in thedifferent conditions. The analysis of flue gas temperature, flow rate of flue gas, watertemperature and flow rate of water impact of heat transfer performance by single factor analysisand orthogonal experiment. The results show that lower flue gas temperature, faster flow rate offlue gas, lower water temperature and faster flow rate of water, the loss of heat transferirreversible is smaller. The more heat transfer is while higher flue gas temperature, faster flowrate of flue gas, lower water temperature and faster flow rate of water. The impact of heattransfer, maximum is flue gas temperature, minimum is flow rate of water. The impact ofthermal resistance factor, maximum is flow rate of flue gas, minimum is water temperature.3. Analysis of dust removal mechanism for fin-tube heat exchanger in the flue gas treatment,including gravity setting, interception effect, inertial impaction effect and thermophoresisdeposition. Flue gas flow rate is linear relationship with pressure loss, and the higher flow rate,the lower pressure loss.