Research On Model Of Thermal Calculation For Quad-sectional Rotory Air Preheater

For a long time in the future,thermal power will still occupy the main power industry in our country.In recent years.With the increasing problems of environmental protection,the increasing engineering application of circulating fluidized bed boiler,and the development for large capacity pulverized coal boiler,quad-sectional air preheater had been developed and applied fast,because of the characteristics of low air leakage rate.At the same time,with the boiler installed a denitration device,the problems of the low temperature corrosion and ash clogging will be more serious for air preheater,so the studied of the heat transfer characteristics and the effect of denitration device on the quad-sectional air preheater,has important guiding significance to safe operation and low temperature corrosion problems of the quad-sectional air preheater.A thermal calculation of quad-sectional rotary air preheater was built with the multi-section lumped parameter method,based on the analysis of the operation mode and heat transfer characteristics of quad-sectional rotary air preheater.The mathematical model is transformed into a general algorithm of the algorithm library of simulation system by using Fortran language.Using a software platform integrated simulation support system,the thermal calculation was solved by means block configuration,And think of the quad-sectional air preheater of a 300 MW circulating fluidized bed boiler unit as an example.The thermal calculation could get the temperature distribution of flue gas,air and heat storage element.The dewpoint of sulfuric acid and ammonium bisulfate were calculated based on the thermal calculation,this airticle explores the distribution of condensation bands of sulfuric acid and ammonium bisulfate condensation in air preheater with denitrification device.The results show that: the relative deviations between calculated values and design values was 0.3% for the outlet temperature of the gas,the relative deviations between calculated values and design values was 0.2% for the outlet air temperature in primary air side,the calculated values are in good agreement with the designed values for the outlet air temperature in left-secondory air side and right-secondory air side;the design values are compared with calculated date for the outlet temperature of gas and air in three different conditions,the maximum were 0.5%,therefore it can proved the correctness and reliability of the model.As the rotor angle increases,the outlet temperature of the flue gas under different working conditions is gradually increased;the temperature of metal wall is increased first,and then reduced to the original temperature slowly.Regardless of whether the furnace desulfurization,the height of condensation bands of sulfuric acid and ammonium bisulfate increases with the the reduction of load;After the installation of denitrification device,when the import temperature of flue gas decrease 10?,the condensation zone of ammonia sulfate and sulfuric acid are moving up,But the influence of condensation of ammonium bisulfate on the air preheater is more than the sulfuric acid;With the improvement of desulphurization efficiency in the boiler,the condensation of ammonium bisulfate in the air preheater was moved downward.