Modified ZSM-5 Molecular Sieve Catalyst Honeycomb Molding And Its Industrial Application

Cyanide containing waste gas has serious harm to human body and environment,the modified ZSM-5 zeolite catalyst our research group product has the excellent performance at purifying it,this paper centers on the modified ZSM-5 zeolite catalyst,solved a series of problems encountered in the industrial process of the catalyst monolithic honeycomb molding.Achieved the monolithic honeycomb catalyst industrial production,and its catalytic activity and quality performance were tested.Finally,the industrial application process of monolithic honeycomb catalyst was completed.Firstly,on the basis of previous studies,propose the extrusion pressure is related to the degree of hardness of the molding material,and the suitable hardness of the extruded honeycomb catalyst is about 12 MPa,based on that,the evaluation standard of the suitable material for extrusion molding was established.The effects of different acid formed aluminum sol on forming monolithic honeycomb catalyst also researched,found that nitric acid is better than acetic acid,oxalic acid and citric acid.Single factor method was used to study the effects of water,SB powder,sesbania powder on the molecular sieve catalyst monolithic honeycomb extrusion molding,found the content of water between 45%?55%is appropriate,and increase the content of SB powder is beneficial to the strength,but overtop is not conducive to extrusion molding,the suitable quality of the content of SB powder is between 7.5%-14%,when the pressure of extruded into strips is between 4-6.5 MPa and the pressure of extruded into monolithic honeycomb is between 9-15 MPa.The use of Sesbania powder is beneficial to the lubrication of extrusion.Study on the suitable extrusion molding formula proved that the amount of modified ZSM-5 zeolite catalyst is 30.4%,extrusion assistant of sesbania powder is 2.6%,SB powder is 13%,nitric acid is 5%and water is about 49%.In the study of drying,let the monolithic catalyst first dried when weight loss of 15%in the shade,then use the temperature programmed method to dry weight loss to 45%,mean the water content is about 5%,which solve the problem of monolithic honeycomb catalyst cracking during drying.The heating rate and calcination temperature were determined by TG.Secondly,in the catalytic activity evaluation and quality detection of monolithic honeycomb catalysts,there are no influence of molding or 600 ?calcination on the crystal structure of zeolite catalyst by XRD,and the effect to pore structure and specific surface area of the zeolite catalyst can ignore by BET.Through the activity evaluation experiment,found in different reaction velocity and oxygen content conditions,the production of the monolithic catalyst showed good catalytic activity,when the reaction temperature is 400?,the conversion rate of C₃H₃N,C₃H₆ and CO was close to 100%,and improve the temperature of reaction,the catalyst still has a good performance.Through compression performance test,the average compressive strength of the monolithic catalyst was 0.4 Mpa in landscape orientation and up to 6.98 Mpa in radial direction.By thermal shock test,prove it is more than 11 times when the monolithic catalyst broken.Finally,the monolithic catalyst production was start-up in acrylonitrile factory of Jilin Petrochemical Co.The effects of catalyst bed temperature and reaction velocity on catalyst activity were studied,when the exhaust gas treatment volume reached 100 thousand m3/h and the gas inlet temperature was 280 ? and the exit temperature was 570 ?,acrylonitrile content remain below 9 mg/m3,the conversion rate of over 95%,and hydrocyanic acid was completely transformed,NOx content was less than 40 mg/m3,in line with the limited demond of national emission standards.