Research On Optimization Of Combustion Characteristics And Safety Of Waste Incinerator

The waste incineration method has the advantages of reduction,harmlessness and recycling,and is widely used in the treatment of domestic waste,medical waste and general industrial waste.In order to improve the efficiency of waste incineration,the combustion characteristics of the waste incinerator and the emission of nitrogen oxides must be studied to achieve the purpose of energy saving and emission reduction.The waste incinerator is an important equipment for the process of waste incineration.When the temperature of the water wall of the incinerator is too high or stress concentration occurs,it is easy to cause an over-temperature tube explosion accident and affect the safe operation of the incinerator.Therefore,it is of great significance to study the combustion characteristics and safety of garbage incinerators.This paper takes a 750t/d waste incinerator in Guangzhou as the research object,and uses numerical simulation,on-site monitoring and survey evaluation to study the combustion characteristics and safety of the waste incinerator.The main research contents are:(1)Establish a calculation model for the waste incinerator,and use the FLIC program to simulate the solid waste combustion process above the bed to obtain data such as the concentration,velocity,and temperature of each flue gas component on the bed surface.Using the obtained data as the inlet boundary condition of FLUENT gas-phase combustion,use FLUENT software to numerically simulate the combustion process under the actual operating conditions of the waste incinerator to obtain the temperature field,velocity field and component field during the operation of the incinerator The distribution and verification of the actual operating conditions of the waste incinerator are compared with the simulated values.The error of each parameter is less than the engineering error.(2)Based on the simulation calculation of actual operating conditions,the combustion process in the furnace was optimized by changing the proportion of secondary air and exhaust air,and the temperature field,velocity field and NO concentration field inside the garbage incinerator under five operating conditions were obtained.The results show that the increase of secondary air ratio speeds up the mixing speed of flue gas,improves the combustion efficiency in the furnace,and the reduction of exhaust air ratio leads to the gradual increase of NO concentration at the outlet of the garbage incinerator.The best air distribution condition for the waste incinerator studied in this chapter is working condition 2.(3)The two-dimensional and three-dimensional models of the water wall of the waste incinerator were established,and the thermal stress of the water wall of the waste incinerator was studied using the thermal-structure coupling analysis module of ANSYS Workbench software.The results show that the thermal stress of the water-walled pipe gradually decreases from the inside to the outside,and the thermal stress at the vertex of the inner wall of the pipe to the fire side is the largest.The maximum thermal stress of the water-cooled wall decreases as the fin thickness increases,the maximum thermal stress increases as the pitch length increases,the maximum thermal stress increases with the wall thickness.The maximum thermal stress point of the water-cooled wall of the garbage incinerator studied is located near the pipe at the wall boundary,and the maximum thermal stress is 116.57 MPa.(4)Study on the safety of waste incinerators.The traditional FMECA method and FMECA method based on fuzzy VIKOR were used to evaluate the safety of the operating system of the waste incinerator.Through analysis,it is found that the main failure mode affecting the safe operation of the waste incinerator is the rupture of the water-wall pipe caused by local high temperature and thermal stress,and corresponding protective measures are given.