Thermodynamic Charactersitics Of Thermal Remediation Processes For Organic-Polluted Solids Based On ANSYS Simulation

With the increasingly serious problem of solid organic waste(SOW),it is urgent to treat them effectively.Thermal remediation processes for organic-polluted Solids has been widely recognized and applied,with the advantages of high efficiency,short cycle periods,waste recycling,etc.The SOW rotary kiln is the most important thermal equipment for thermal remediation processes for organic-polluted solids,which is affected directly by safety,stability and the economy of the SOW rotary kiln.Therefore,the study of thermal characters on the SOW rotary kiln and rotary kiln for waste-heat utilization is carried out.In this paper,problems such as temperature distribution,heat flux density,thermal properties and thermal efficiency of rotary kiln are discussed.The modeling and analysis of results show that the temperature and heat flux density of each layer of SOW rotary kiln increase first then decrease along the axial direction,and the peak value of temperature and heat flux appear at 20 m from the kiln head.According to the change of radial temperature,the heat preservation effect of firebrick is best,followed by cylinder and kiln skin.It is further concluded that the heat stress of fire resistant brick and kiln crust increases and decreases alternately along the axial direction,while the heat stress of the cylinder changes relatively gently,but the heat stress value increases steeply at the four rims,which is caused by the constraints of the rims.In addition,taking into account high calorific value of flu gas from the SOW rotary kiln,a residual heat utilization rotary kiln is used to recycle flu gas heat,and the finite element model of the residual heat utilization rotary kiln was established.The temperature distribution of the residual heat utilization rotary kiln,material,the change of heat flux density in the rotary kiln and so on were simulated,and the effects of soil types on thermal characters were discussed.The results show that the sand cooled the flue gas most effectively,followed by the loam,while clay has the worst ability of cooling flue gas.Furthermore,the effect of inlet flue gas temperature on the thermal efficiency of the residual heat utilization rotary kiln was explored,the conclusion is that thermal efficiency reaches its peak when the inlet flue gas temperature gets to 780 ℃,with the loam treated,while the thermal efficiency peak of rotary kiln,when the sand treated,corresponds to an inlet flue gas at the temperature of 760℃.The physical models of the SOW rotary kiln and the residual heat utilization rotary kiln for waste-heat utilization are built based on ANSYS,and the heat resource of dual-tube rotary kiln comes from the SOW rotary kiln,reusing solid organic waste effecitvely.