Synergetic Effects Of Silicon Carbide And Molecular Sieve Loaded Catalyst On Microwave Assisted Catalytic Oxidation Of VOCs

Along with the rapid development of modern industry, volatile organic compoundshave become one of the main atmospheric pollutants in our country. Catalytic oxidationtechnology has advantages of low light-off temperature and high degradation efficiency,which has caused more and more concerns. Distinguished from traditional electricheating, microwave heating has the selectivity, in order to make the catalyst in themicrowave field more effectively the use of microwave energy to improve theefficiency of catalytic oxidation, need with the help of the reactivity ofmicrowave-absorbing material. On the other hand, to reduce the energy consumptionand improve the efficiency of catalytic oxidation, absorbing material with catalyst inwhich way is particularly important. Therefore, research work on how to combinemicrowave-absorbing materials and catalyst under microwave irradiation is importantfor catalytic oxidation of VOCs.Molecular sieve loaded catalyst was prepared by impregnation method, and typicalaromatic VOCs toluene and halogenated VOCs chlorobenzene were selected as the goalpollutants to be treated in the experiment of microwave assisted catalytic oxidation, andmicrowave-absorbing material silicon carbide and the catalyst were investigated forcatalytic oxidation of toluene under microwave irradiation. Research work examinedabsorbing heat performance of silicon carbide and molecular sieve carrier. Researchwork examined effects of silicon carbide and molecular sieve loading Cu-V catalyst’smixture ratio as well as mixed approach changes on degradation of toluene. Researchwork examined bed temperature distribution in the fixed bed reactor and molecular sieve loading Cu-V-Ce catalyst’s adsorption of toluene. Research work examineddegradation effect of microwave assisted catalytic oxidation of chlorobenzene under theoptimal conditions. Characteristics of catalyst were measured through scanning electronmicroscope, specific surface area test and X-ray diffraction analysis. The economy ofthe common microwave heating mode and the heat storage type microwave heatingmode were be compared.The result showed that absorbing heat performance of both Qinghai Yongqiangsilicon carbide and Tianjin Kermel5A molecular sieve were good, which could improvethe utilization efficiency of microwave energy and reduce energy consumption ofreaction. Fixed bed reactor had advantages of both thermal storage property andlow-temperature catalytic oxidation when20%silicon carbide was filled at the bottomof the reactor, and this could effectively improve utilization of microwave energy aswell as catalytic oxidation efficiency of toluene. Under microwave power of75W and47W, complete-combustion temperatures of molecular sieve loaded Cu-V catalyst andCu-V-Ce catalyst to toluene were325℃and160℃, respectively. The good adsorptionof toluene of molecular sieve loading Cu-V-Ce catalyst could effectively extend thetoluene’s residence time on the catalyst, which promoted the catalytic oxidation oftoluene. In the catalytic oxidation experiments of chlorobenzene, two kinds of catalystalso showed good activity in low temperature and catalytic performance.Characteristics of the catalysts showed that mixture of rare-earth element Ceincreased dispersion of active components in the surface of catalyst, micropore structureof catalyst effectively guaranteed high adsorption capacity for toluene, while amorphousphase of Cu and V oxides increased activity of catalyst greatly. Economic analysisshowed that energy consumption of the heat storage type microwave heating process islower than the ordinary microwave heating process, which had certain practicalapplication prospect.