Deactivation Reasons And Regeneration Routes Of Catalyst For Cumene Synthesis

Deactivation and regeneration processes of QZ-2000 catalyst of Jilin PetrochemicalCompany Ltd for alkylation of benzene and propylene to forming cymene are studied. TG isapplied to ascertain the coke nature in used catalyst; XRF result showes that there isarsenic-containing species, which indicate that both coking and arsenic poisoning contributedto deactivation of QZ-2000 alkylation catalyst. Considering of properties of coke and arsenicspecies, deactivated alkylation catalyst is washed by organic acids to remove arsenic andcalcined to remove coke. Three regeneration routes for the deactivated catalyst areinvestigated and compared, which are "calcined directly"(Routeâ… ), "acid washed first thencalcined" (Routeâ…¡) and "calcined firstly, acid washed secondly, calcined again thirdly"(Routeâ…¢). Both ICP-AES and Ag-DDC are used to detect the content of element As in thedeactivated catalyst. It is shown that citric acid is more effective than formic acid and aceticacid. The removed arsenic ratio increases with washing temperature and time, and does notchange obviously under conditions of higher than 80℃and more than 2h. Immerged into 2ï¼…citric acid, 27.4ï¼…arsenic is removed from deactivated catalyst under 80℃for 4h. There areno distinct influence for zeolite framework by three regeneration routes in XRD spectrumgraph; NH₃-TPD curves showes that strong acid sites of catalyst has been recovered well byregeneration Routeâ…¡than regeneration Routeâ… and regeneration Routeâ…¢. The regeneratedcatalyst by Routeâ…¡in alkylation reaction performes good activity compared with freshQZ-2000 catalyst. So We can conclude that Routeâ…¡is the optimal regeneration scheme forindustrial deactivated QZ-2000 catalyst of alkylation. Moreover, Routeâ…¡is also fit for thedeactivated QZ-2000, QZ-2001-04 and QZ-2001-05 catalysts of Lanxing Company Ltd inHarbin, and their catalytic activity recover obviously after regeneration by Routeâ…¡.