Effect Of Microwave Heating And Magnesium Doping On Catalytic Performance Of MnO₂ And Its Industrial Application

The rapid development of our country's industry is accompanied by the rising emissions of industrial volatile organic compounds?VOCs?.Excessive organic gases in the air have many hazards to the environment and the human body.Developing an energy-saving and efficient VOCs treatment technology is of great significance to environmental protection and national health.At present,catalytic combustion technology is being widely used and concerned due to its characteristic of simple process and Purification thoroughly.The catalytic activity and economy of the catalyst are the key factors which influence the catalytic combustion technique applied to engineering.At the same time,the traditional heating methods have the problems of slow heating and uneven heating of the bed,which limits the further application of the catalytic combustion technique.MnO₂ has been extensively studied for its special pore structure and cheap and easy-to-obtain properties,but pure commercial MnO₂ has the problems of high light-off temperature and low activity.In response to these problems,this paper prepared higher catalytic activity?-MnO₂ by traditional hydrothermal oxidation reduction and studed the effect of Mg doping on the structure and activity of manganese dioxide,further studied the effect of microwave heating on the catalytic performance of MnO₂.Taking Guangzhou Auto Parts Enterprise as an Example to Verify the Effect of Microwave Assisted MnO₂ Catalysis on VOCs Treatment.The main research contents are as follows:?1?Effect of Mg Doping on the Catalytic Performance of MnO₂.Mg-doped?-MnO₂were synthesised by hydrothermal method,The results show that Mg doping can promote the crystallization of MnO₂ during the reaction and increase the specific surface area and catalytic activity of?-MnO2 significantly.Specific surface area of Mg-doped?-Mn O₂ increase at first and then descend with the doping amount increasing from 0 to 30%.The specific surface area of the sample 10Mg/?-MnO₂ was the highest,reaching 110.2m²/g,which was 2.28 times of0Mg/?-Mn O2.In the catalytic toluene experiment,Mg-doped/?-MnO₂ showed more excellent catalytic activity than pure?-MnO₂,The complete conversion temperature(T₁₀₀)of 10Mg/?-MnO₂ is reduced by 50?compared to 0Mg/?-MnO₂ and the Thermal stability of 10Mg/?-MnO₂ is better than pure?-MnO₂.?2?Effect of Microwave on MnO₂ Catalytic Activity.Compared with the traditional resistance tube furnace heating,microwave heating with fast,low energy consumption characteristics,and Microwave has its non-thermal effect,can effectively reduce the catalyst on the toluene light-off temperature and complete conversion temperature.Compared with the heating in the resistance furnace,Light-off temperature(T₁₀)and complete conversion temperature(T₁₀₀)of 0Mg/?-MnO₂ decreased by 21?and 20?,respectively.10Mg/?-MnO₂ decreased by 32?and 18?respectively under microwave heating.At the same time,the thermal stability of the catalyst when microwave heating is obviously better than the resistance furnace heating.?3?Taking an auto parts manufacturers VOCs treatment project as an example to verify whether microwave assisted manganese dioxide catalyst technology can effectively purify industrial emissions of organic waste gas.Determined and analyzed the company's VOCs treatment program,And the VOCs purification equipment was further designed and selected.The actual engineering operation shows that the microwave assisted manganese dioxide catalyst can effectively degrade the organic waste gas,and can keep 90%of the removal rate of toluene and xylene after stable operation,and the removal rate of non-methane total hydrocarbons can reach 90%,Emission concentration is far lower than the local standards in Guangdong Province.The average daily operation and maintenance costs of equipment is about 338 yuan and has high user satisfaction.It was shown that microwave assisted manganese dioxide catalyst technology is a cost-effective catalytic treatment technology,with a high value of popularization and application.