Effect of mass ratio of shell to core on hydrocracking performance of β@SBA-15 composite zeolite
A series of β@SBA-15 composite zeo-lites with different mass ratio of shell to core(here-inafter referred to as core-shell ratio)were pre-pared,and the acidic sites were constructed in the shell material.After acidic sites were constructed,β@AlSBA-15 composite zeolite was used as the main cracking component to prepare catalyst,and the effect of the core-shell ratio of the composite ze-olite on the hydrocracking performance of the cata-lyst was investigated on 200 mL fixed bed reactor.The results showed that the optimal core-shell ratio for composite zeolite was 6∶4.A high core-shell ratio could result in incomplete core-shell structure,while a low core-shell ratio could lead to separated phase.Under similar conversion rate conditions with Middle East vacuum gas oil as raw material,theβ@SBA-15 composite zeolite with a core-shell ratio of 6∶4 showed the best hydrocracking performance,the highest selectivity to middle distillate oil(84.9%),the lowest freezing point of jet oil and the lowest freezing point of diesel at-61 ℃ and-5 ℃ respec-tively.