Study On Operation And Structural Optimization Of Large Domestic Waste Incinerator

At present,grate furnace is the main type of waste incinerator in the world.Grate furnace technology has become mature in developed countries,while at home,it is imported from abroad and formed after localization,and there are still various problems.In view of high moisture characteristics of domestic garbage,the research and development of large and efficient garbage incineration equipment with low thermal reduction rate,low pollution emission and versatility has become an important trend in this field.In this paper,the 600 t/d waste incineration grate furnace designed by Jiangsu Tianying Green Energy Equipment Co.Ltd.was used as the research object.Bed calculation software FLIC and commercial CFD software Fluent were combined for the numerical simulation of combustion in the waste incinerator.The combustion condition of municipal solid waste(MSW)of different heat values under different run parameter variables(including proportion of primary and second air,primary air temperature and primary air volume ratio)and structural parameter variables(including rear arch angle and first rear arch position)were predicted.Temperature distribution and flow field distribution inside the incinerator and gas component and pollution concentration at the exit of the flue were given.The optimal run parameter variables and structural parameter variables for incinerators incinerating waste with different heat values were obtained according to the simulation results,which provided theoretical support for equipment design and operation.To verify the simulation results,experiments were carried out on the basis of actual projects.Through the research on the optimization of the MSW incinerator,it was know that for MSW with a heat value of 6200 kJ/kg,the best proportion of primary and second air was 78.5%:21.5%.Increasing or decreasing the proportion wouldn't improve the combustion effect.As for MSW with different heat values,raising the air temperature of the dry section and combustion section of the primary air as much as possible would improve the combustion condition in the incinerator.While as for high heat value MSW,much attention should be payed to prevent temperature excursion.The best air temperature of the dry section and combustion section of the primary air for MSW with a heat value of 6200 kJ/kg were 493 K and 458 K respectively.In addition,for MSW with different heat values,increasing the air volume ratio of combustion section properly would improve the combustion condition.Likely,temperature excursion should be prevented cautiously for MSW with high heat value.The best primary air volume ratio for MSW with a heat value of 6200 kJ/kg was 30%:50%.Through the study of the structure optimization of the MSW incinerator,it was known that increasing the angle of the rear arch with the post point of the post arch fixed had a limited ability in improving the combustion condition,while reducing the angle would deteriorate the combustion condition in the furnace.Therefore,the best design angle of the rear arch is 30?.The position of the first rear arch had little impact to the combustion condition for MSW with a heat value of 6200 kJ/kg.Moving the position of the first rear arch had a greater impact on the combustion condition for MSW with a high heat value.