Preparation And Application Research Of SAPO-34Sieve Thin-filmed Catalyst

Ethylene and propylene are important basic petrochemical raw materials and they are the most consumed products in petrochemical industry. Ethylene and propylene are traditionally produced from petroleum feedstock by catalytic or steam cracking process, while the supply of petroleum is insufficient, the price volatility is large. On the basic of such situation, coal to olefins via methanol is drawing the world’s attention.The preparation of industry catalyst with high catalytic performance is the key technology that constraint industrialization of methanol to olefins and catalyst formation is an important factor influencing the performance of industry catalyst.Ehance the catalytic performance and extend lifetime of SAPO-34sieve catalyst is the main aim of my paper. Fluidized-bed spray coating technology was adopted for the forming of MTO catalyst and the thin-filmed catalyst with "onionskin" structure is prepared by coating mechanism of particles in fluidized-bed spray granulation.The active component in thin-filmed catalyst was adhered to surface, this structre can enhance update rate of catalyst, decrease diffusion resistance of gas. Thus the selectivity of ethylene, propylene can be enhanced and secondary reaction can be decreased. The thin-filmed catalyst is regular sphere, the flowability is good, so it can be used in moving bed. Parameters that influenced the particals growth rate are researched in the experiment. The particles growth rate increased with an increasing of spray rate, sieve catalyst concentration and mass rate of sieve components with binder. There is no big difference in growth rate of the thin-film catalyst prepared by SAPO-34sieve catalyst and spray dried SAPO-34catalyst. While the economic benefit with SAPO-34sieve catalyst is bigger because of the absence of spray drying forming process.The attration investigate of thin-film catalyst is performed according to ASTMD5757-2000. The thin-filmed catalyst’s attration rate is1.36wt%per hour. The catalytic performance of thin-filmed catalysts is evaluated in fixed bed reactor. The thin-filmed catalysts exhibit good performance when the evaluate time lasting196minutes. The conversion of methanol is larger than99.5%, the ethylene selectivity is up to41.56%and the propylene selectivity is up to39.24%. The catalytic performance of thin-filmed catalyst declined when reactation time is212min. The catalytic performance of the regenerated thin-filmed catalysts is compared with the original thin-filmed catalysts. The regenerated thin-filmed catalysts exhibit the same catalytic performance with the original thin-filmed catalysts.The residence time of thin-filmed catalyst can be controlled efficaciously in moving bed, thus the amount of coke can be controlled efficaciously which is conducive to enhance the selectivity of ethylene and propylene. The abrasion declines because of the small collision among the thin-filmed catalyst particles, so the effective life is extended.