Research On The Intensification Of Heat Transfer In Flue Gas Condensing Heat Exchanger And Engineering Application

The main future direction of energy technology development is making use of energyeconomically, efficiently and cleanly and exploiting new energy resources. How to make useof natural gas efficiently and how to improve the heat energy utilization of natural gas thermalpower equipment to the maximum level is a hot topic to be solved in the fields of energy andenvironment academic community and engineering application during the Twelveth Five-YearPeriod.The paper is aiming at researching strengthening technology of flue gasconvection-condensation heat transfer and further recovery and utilization technology of fluegas condensing waste heat, with theoretical and experimental studies combining theengineering measurement, studying on the law of flue gas convection-condensation heattransfer on new compound anticorrosion surface and heat transfer performance of newcompound anticorrosion surface condensing heat exchanger. Energy saving program design ofnatural gas boiler room has been completed. The tracking and monitoring tasks have beendone when the application of new compound anticorrosion surface condensing heat device tothe reconstruction project of waste utilization in nature gas boiler room is completed, whichprovide the basis for the development of flue gas condensing heat depth recycling device andprovide technical support for improving our country natural gas using level.Establish visualizing heat transfer experiment system by using CCD high-speed cameraapparatus, visual observation and the heat transfer experiment research toconvection-condensation heat transfer characteristics and condensing forms of gas on newcompound anticorrosion flat surface have been carried on. Come to a conclusion that the wayof smoke convection-condensation heat transfer is drop wise condensation, and obtainexperimental correlation on flue gas forced convection-condensation heat transfer.Comparedto the previous anti-corrosion surface experiment results, the efficiency of gas convectivecondensation heat transfer increased by6times at least.Law of convective condensation heat transfer in flue gas side of newcomposite corrosion surface condensing heat exchanger was studied in the experiment.Influence factors and the law of temperature conductivity of heat exchanger can beobtained,and experimental correlation on flue gas forced convection-condensation heattransfer of new compound anticorrosion heat exchanger can be obtained as well.Completing computational analysis of operation condition and smoke condensate heatsaving potential of three existing boiler rooms(ten boilers, and two direct-fired machines), andcompleting project design of energy saving renovation engineering of waste heat utilization,which provide technician support for energy saving control of existing boiler rooms.Take use of the anticorrosive unit of further recycling condensing heat of the flue gas inutilization of waste heat and energy-saving projects of natural gas boiler room, and carry outtracking and detecting throughout the heating season. Measured data show that, for the boilerswhich thermal efficiency is over95%and potential of exhaust heat recovery is relatively small, exhaust gas temperature is down to50℃from190~200℃, and thermal efficiency isimproved by9.8%,and boiler total thermal efficiency improved to105%after taking use ofthe unit of recycling condensing heat of flue gas.At the same time, we can obtain eperimentalcorrelation on flue gas forced convection-condensation heat transfer, and obtain correctionvalue of theoretical calculation of heat recovery device energy saving rate.