Inactivation Of The Impact On The Performance Of The Composite Molecular Sieve Catalyst Cracking

Deactivation of bizeolite (zeolite Y and ZRP-1) cracking catalyst during hydrothermal treatment and metal contamination was investigated. Test results indicated that ZRP-l zeolite possessed better hydrothermal stability, metal resistance, secondary crackability and lower hydrogen transfer activity than that of zeolite Y zeolite Y exhibited excellent large molecule crackability. The combination of the two types of zeolite was more than just a mixture, synergistic effect occurred. The changes of product distribution between the fresh and deactivated bizeolite were found to be more significant than that of individual zeolite. It was also observed that after deactivation of the bizeolite cracking catalyst the light olefin yield increased significantly at the expense of gasoline. It might be explained that not only the catalytic performance of the individual zeolite, but also the relative proportion of the two types of zeolite was altered during deactivation. Therefore, the synergistic effect could be modified. As a result, the secondary crackability and light olefln selectivity were enhanced. It is proposed that the changes in yields and selectivity might be minimized during the deactivation of the bizeolite cracking catalyst by proper adjusting the relative proportion of the two types of zeolite.