Study On Key Technologies Of Water Wall Anti-corrosion For Large Scale Msw Grate Incinerator

With the rapid development of China's economy and the acceleration of urbanization,the proper disposal of municipal solid waste?MSW?has become a key issue that Chinese cities need to resolve.Incineration is now the preferred technology for MSW disposal because of its advantages of reduction,harmlessness and resource recovery.However,due to the complex and variable composition of MSW,the corrosion of the water wall is severe during incineration,which is a potential threat to the safety,stability and environmental protection of the incinerator operation.In this paper,the experimental method was adopted to study the feasibility of Ca?OH?₂ in the furnace to absorb the acid gas in the flue gas to eliminate the corrosion of water wall.The adsorption efficiency and optimal addition ratio of Ca?OH?₂ to HCl were analyzed.Anti-corrosion performance of surfacing technology.Secondly,through the thermal calculation of the incinerator,the corrosion rate of the wall of the water wall is investigated under different flue gas temperature,ash scale thickness,excess air coefficient,load and waste heat value.Finally,based on the results of thermal calculations,the FLIC+FLUENT numerical simulation method is applied to optimize the air distribution scheme of the incinerator to improve the temperature field and velocity field of the furnace and the flue,thereby the high temperature corrosion of the water wall was reduced.The results show that the application of calcium-based absorbent during the incineration may significantly reduce the corrosion of acid gas,but it has a strengthening effect on the corrosion of alkali metal co-melt,and it is necessary to strictly control the quantity of absorbent.The surfacing process can achieve better anti-corrosion effect,but it has little effect on the removal of corrosion elements in the ash.The increase of the thickness of the ash layer,the increase of the calorific value of the garbage,the decrease of the excess air ratio,and the increase of the load all increase the corrosion rate of the water wall.The proportion of air distribution at each level of primary wind:10:10:27:27:26;the ratio of primary and secondary air ratio:0.7:0.3;the ratio of the secondary air to the air outlet:0.4:0.6,the best operation for optimizing the air distribution condition.The test is carried out to verify the operation condition.