| The commercial HZSM-5 molecular sieve was used as the precursor and pretreated with NaOH solution to synthesize HZSM-5/Y composite molecular sieve by the addition of aluminum source and Y-directing agent, and the HZSM-5/Y composite molecular sieve was characterized by XRD, SEM and BET. The effect of NaOH solution concentration on the structure and morphology of the composite molecular sieve was investigated. The catalytic properties of the composite molecular sieve in the cracking oleic acid reaction were further investigated and compared with the catalytic properties of commercial HZSM-5 molecular sieve. The results showed that the HZSM-5/Y composite molecular sieve prepared with 1.5 mol/L NaOH solution had a selected molecular sieve structure and exhibited good performance in the catalytic cracking reaction. When the molecular sieve synthesized was used, the liquid product yield reached 542%, the oleic acid deoxidation rate was 38.5%, and the acid value of the liquid product was 2.6 mgKOH/g at reaction temperature of 475 ℃ and mass space velocity of 6.99 h-1. Compared with the commercial HZSM-5 molecular sieve, the composite molecular sieve had higher selectivity to acyclic alkane of 5-12 carbon atoms, and the cracked liquid product had lower acid value,but the life of the composite molecular sieve was poor. |
