Study On The Whole Honeycomb Molding Process Of Different Silicon-aluminum Ratio ZSM-5 Molecular Sieves And Purifying The Performance Of Vocs

Volatile organic compounds are important part of atmospheric pollutants,and their treatment methods include adsorption technology and catalytic combustion technology.ZSM-5 zeolite is a common solid adsorbent and catalyst carrier.Powdered ZSM-5 zeolite cannot be used in fixed bed reactors,and ZSM-5 zeolite powder needs to be molded.The whole honeycomb formed zeolite has the advantages of reduced pressure and low resistance.Therefore,this thesis mainly studies the overall honeycomb molding process of different silicon-aluminum ratio ZSM-5 molecular sieves and the performance of purifying VOCs-containing exhaust gas.In this thesis,the whole honeycomb forming process of ZSM-5 zeolite with different silica-alumina ratios was studied.Investigate the factors affecting of the mechanical strength and performance in different silicon-aluminum ratio ZSM-5 molecular sieves after molding.Influencing factors include binders,extrusion aids,water to powder ratio,plasticity,drying conditions and other additives.The experimental results show that the optimum process conditions for the overall honeycomb molding of ZSM-5-300 molecular sieve are as follows:The plasticity index Pi of ZSM-5-300 molecular sieve mud should be 0.35.Silica sol should be used as the binder,and the relative content of silica sol should be 15%.The content of Sesbania powder is 4%.The relative content of hydroxypropyl methylcellulose should be 3%.The water to powder ratio should be 0.51.The optimum process conditions for Cu-ZSM-5-30 molecular sieve integral honeycomb molding are as follows:The plasticity index Pi of Cu-ZSM-5-30 molecular sieve mud should be 0.36.Aluminum sol should be used as the binder,and the relative content of aluminum sol should be 15%.The content of Sesbania powder is 5%.The relative content of hydroxypropyl methylcellulose should be 4%.The water to powder ratio should be 0.8.The relationship between the water-powder ratio and the ratio of silica to aluminum in the overall honeycomb forming of ZSM-5 zeolite with a ratio of silicon to aluminum of 30,120,170 and 300 was studied.In this thesis,the experiment of adsorbing toluene-containing waste gas and desorption of toluene by ZSM-5-300 whole honeycomb molecular sieve was studied.Investigating factors affecting the adsorption and desorption of toluene on ZSM-5-300 monolithic honeycomb molecular sieve,including adsorption temperature,inlet toluene partial pressure,molecular sieve percentage,desorption temperature.The experimental results show that ZSM-5-300 whole honeycomb molecular sieve adsorbs toluene-containing exhaust gas.When the adsorption temperature is 20?,the volumetric space velocity is 2000 h-1,and the inlet toluene partial pressure is 30 Pa,ZSM-5-300 whole honeycomb.The molecular sieve adsorbed toluene had a penetration adsorption capacity of 12.4 mg/g and a saturated adsorption capacity of 16.9 mg/g.When ZSM-5-300 whole honeycomb molecular sieve desorbs toluene,the desorption rate reaches 90%when the desorption temperature is 200?,and the time required for the desorption rate to reach 90%is 3 h.The prepared Cu-ZSM-5-30 monolithic honeycomb molecular sieve was used to catalyze the oxidation of benzene,toluene and xylene.Cu-ZSM-5-30 monolithic honeycomb molecular sieve catalytic combustion of benzene-containing waste gas.The catalytic combustion temperature is 440?,the volumetric space velocity is 12000 h-1,the inlet benzene concentration is 2000 mg/m3,and the molecular sieve percentage is 85%.The conversion rate of benzene can reach 92%;Cu-ZSM-5-30 whole honeycomb molecular sieve catalytic combustion of toluene-containing waste gas,when the catalytic reaction temperature is 320?,the volumetric space velocity is 12000 h-1,and the inlet concentration is 3000.When the percentage of molecular sieve is 85%,the conversion rate of toluene can reach 93%.Cu-ZSM-5-30 monolithic honeycomb molecular sieve catalytic combustion of xylene-containing waste gas.When the catalytic reaction temperature is 340?,the volumetric space velocity is 8000 h-1,the inlet concentration is 2000 mg/m3,and the molecular sieve percentage is 85%.The conversion of xylene can reach 92%.