Simulation And Optimization Of Coal Erosion Wear Of The Coal Economizer Tube Bundle In Waste Incineration Boilers

With the development of national economy and the increase of urban population,the phenomenon of "garbage siege" brought by the increase of urban waste generation in China is becoming more and more prominent.The number of waste incineration power plants is increasing because they can realize the harmless,resourceful and quantified domestic waste,and have good economic and social benefits.Waste incineration boiler is one of the three main engines of waste incineration power plants,and its safe operation is related to the safe production of enterprises.In actual production,the high-temperature flue gas in the boiler flue will carry soot particles to impact the wall of the boiler economizer tube bundle thus causing serious erosion and wear,affecting the safe operation of boiler equipment.Therefore,it is important to study the flow characteristics and erosion wear characteristics of flue gas and soot particles in the flue to reduce the erosion wear of the boiler economizer and ensure the stable operation of waste incineration power plants.In this paper,the chemical composition and metallurgical organization of the coal economizer tube sample were determined by using energy spectrum analysis and metallurgical organization analysis for a boiler coal economizer tube bundle of a waste incineration power plant in Fuzhou City.Fluent software was applied to establish the coal economizer erosion and wear model,and the flue gas flow field was optimized by setting the wave-type deflector,and the flue gas flow field distribution clouds,soot particle trajectory and erosion and wear characteristics were studied before and after optimization.The influence of four factors,such as different flue gas velocity,soot particle size,mass flow rate and longitudinal pipe distance,on the erosion rate of the coal economizer tube bundle is analyzed,and the correlation between the four factors and the erosion rate of the coal economizer tube bundle is found using MATLAB software program based on the gray correlation analysis.The main findings of the study are as follows:(1)The material composition and metallurgical organization of the coal economizer tube bundle after erosion and wear meet the requirements of relevant standards.(2)The uniformity of the flue gas flow field is improved and the erosion and wear phenomenon is significantly reduced after setting the wave-type deflector.(3)Under the conditions of flue gas velocity,soot particle size and mass flow rate,the optimized average erosion rate is reduced by about 15%,25% and 18% respectively;under the condition of longitudinal pipe distance,the optimized maximum average erosion rate is reduced by about 12%.(4)When the flue gas physical parameters(flue gas velocity,soot particle size,mass flow rate)and the structural parameters of the tube bundle(longitudinal tube spacing)increase,the average erosion rate of the coal saver tube bundle increases.When the flue gas velocity becomes larger,the average erosion rate of the wall surface of the coal economizer bundle increases.When the soot particle size increases,the average erosion rate of the tube bundle wall surface increases,but the increasing trend will gradually decrease,and the increase will also increase when the flue gas velocity increases.When the mass flow rate increases,the average erosion rate of the tube bundle increases linearly with the increase of mass flow rate,and the larger the soot particle size,the larger the increasing trend,and shows a linear increase.With the increase of longitudinal pipe distance,the average erosion rate of pipe bundle will also increase,but the increase is slow,when the mass flow rate increases,the average erosion rate of pipe bundle wall will also increase.(5)Using gray correlation analysis and MATLAB programming,the correlations of four factors,namely,flue gas velocity,soot particle size,mass flow rate,and longitudinal pipe distance,on the average erosion rate were calculated,and the factors were ranked according to their effects on the average erosion rate,from largest to smallest,in the following order: flue gas velocity,soot particle size,mass flow rate,and longitudinal tube distance.