黏合剂对其ZSM-5分子筛成型物裂解石脑油的影响

为考察成型时,黏合剂性能对ZSM-5分子筛的影响,对同一分子筛用六种不同黏合剂捏合,挤条成型,进行SEM、NH₃-TPD和N₂物理吸附表征。结果表明,六个成型物在形貌和BET比表面积均无明显差异,二次孔数量明显比分子筛原粉增加。所用纯硅溶胶黏合剂的成型物,其NH₃-TPD酸量、微孔体积和微孔比表面积低于其分子筛原粉。所用含铝黏合剂的成型物,其NH₃-TPD酸量、微孔体积和微孔比表面积变化不明显,BJH累积孔体积明显增加。在固定床反应器中于600 ℃裂解石脑油。发现,纯硅溶胶黏合剂成型物的乙烯+丙烯收率明显低于含铝黏合剂。

Influence of adhesive on the performance of extruded ZSM-5 catalysts in naphtha cracking

Six adhesives were used to prepare ZSM-5 catalysts through kneading and extruding.The extruded ZSM-5 catalysts were characterized by SEM,NH3-TPD and N2 physical sorption and used in naphtha cracking.The results indicated that these ZSM-5 extrudants have no significant differences in their morphology and specific surface area,but have markedly more secondary pores compared with the original ZSM-5 sample.With pure silicon collosol as the adhesive,the resultant ZSM-5 extrudant exhibits lower acid amount,cumulative pore volume,micropore surface area and volume than the original ZSM-5 sample;however,the acid amount,surface area and cumulative pore volume of the extrudants obtained with aluminum-containing adhesives are almost identical to those of the original ZSM-5.For the naphtha cracking in a fixed bed reactor at 600 ℃,the yield of ethylene plus propylene over the extruded ZSM-5 catalyst with silicon collosol as additive is lower than that over the extrudants obtained with aluminum-containing adhesives.