COMSOL Simulations Of Wall Flow Reactors For Toluene Catalytic Combustion

In recent years,with the rapid development of urbanization and industrialization,the problem of environmental pollution has become more and more prominent,especially the serious pollution of atmospheric environment.Volatile organic compounds are the main components of air pollutants.VOCs are very harmful to both the environment and human health.They can not only form photochemical smog,but also lead to the greenhouse effect,stratospheric ozone depletion and fine particulate matter PM2.5 and other secondary air pollutants.Toluene is a typical kind of VOCs,and also an important raw material for organic chemicals in industrial field,which is widely used as a solvent in coatings,dyes and other industries,and usually emitted at a lower concentration.Varies of methods have been proposed for toluene removal so far,including absorption,condensation,membrane separation,catalytic combustion,biological methods,and molecular complexation technique,and the catalytic combustion method is considered to be the most effective means for toluene removal.Compared with thermal combustion,toluene can be fully burn without continuously applying a large amount of external heating source and any secondary pollution by using catalytic combustion method.This subject is based on the theoretical knowledge of toluene catalytic combustion.The Mars-van Krevelen kinetic model proposed was adopted as kinetic parameters.In order to avoid cumbersome,repetitive,and long-period experiments,varies of simulations were conducted based on the same experimental conditions as Ordanez's.Thus,the correctness of the model was also verified.The COMSOL Multiphysics is a large-scale finite element analysis software with powerful multi-physics coupling analysis capability,It has the advantages of high computational efficiency and stable performance,which ensures the accuracy and credibility of numerical simulation.Based on the kinetic equation of Pt catalytic combustion toluene,a two-dimensional numerical simulation model consedered energy conservation,momentum conservation and energy conservation was established,and used to simulate the catalytic combustion process of low concentration toluene in flow reactor and wall flow reactor.The results show that the performance of toluene in the wall flow reactor is better than that in the flow reactor;When the initial temperature reaches at 523 K,the toluene can be completely eliminated.The smaller the pore width is,The more adequate toluene reaction can be,but too small pores are not suitable for the industry conditions;As the inlet flow rate decreases,the conversion of toluene improves,however,the too low inlet flow rate will lower the reaction temperature;With a higher initial concentration of toluene,both of the reaction temperature and toluene conversion rate can be higher.This study has important guiding significance for revealing the multi-physics coupling mechanism in the catalytic combustion of toluene and achieving efficient removal of toluene.