Research On Control Method Of Plasma Furnace For Solid Waste Treatment

With the continuous development of modernization,urbanization,and industrialization in China,municipal and industrial solid waste have been increasing in recent years,posing an increasingly severe challenges to the solid waste treatment capacity in China.Among the solid wastes,aluminum ash,especially secondary aluminum dross,is a toxic and hazardous waste listed in the national non-ferrous metal smelting waste list,and its harmless treatment and resource utilization are imminent.Traditional aluminum dross disposal methods,including pyrometallurgical processes and hydrometallurgical processes,have obvious limitations.Plasma torch technology,as an emerging pyrometallurgical technology for aluminum dross recovery,will have an increasingly wide prospects in the aluminum dross treatment market due to its advantages of high temperature,easy control,high enthalpy value,and low pollution.In this paper,the temperature control process of aluminum dross roasting is studied based on the pilot line of plasma aluminum dross disposal.The main research contents are as follows:(1)Analysis of the plasma furnace roasting system: The process flow of plasma furnace roasting was mainly analyzed,the temperature control requirements and difficulties of plasma furnace roasting system were studied,and the temperature control scheme of plasma furnace was designed.(2)Calculation of heat balance of rotary kiln: Based on the analysis of the chemical reaction and heat transfer process of the aluminum ash roasting process,the balance model taking the materials and heat within the scope of the rotary kiln as the research object were established,and the balance of materials and heat were analyzed.Calculations of energy consumption and oxygen content of the carrier gas were calculated.(3)Research on plasma torch power control method: A plasma torch power curve test system was established,and the relationship between plasma torch power-flowcurrent was tested;A plasma torch power control method based on look-up table and nonlinear interpolation was proposed.(4)Research on rotary kiln temperature control method: Through the calculation of the heat balance of the rotary kiln,the mechanism model of the rotary kiln was established,and the model was modified according to the temperature measurement data of the temperature in the kiln obtained by the experiment;through the simulation analysis of the response process of the rotary kiln temperature PID control,the PID parameters were adjusted in combination with the mechanism model.The actual debugging shows that the above temperature control algorithm has small overshoot and fast response,which can better realize the temperature control of the rotary kiln.