纳米HZSM-5沸石酸度的调节及对液化气裂解反应的影响

Tailoring the Acidity of Nano-sized HZSM-5 Zeolite and Its Effect on the Catalytic Cracking of LPG

通过对纳米HZSM-5沸石进行钠离子浸渍改性和在小型常压固定床反应器中开展碳四液化气催化裂解制丙烯反应研究,探讨了催化剂酸度对反应选择性的影响.结果表明,钠离子改性能够选择性地去除纳米HZSM-5沸石表面的强酸中心,而对弱酸中心则基本无影响.在用钠离子改性基本上消除催化剂强酸中心的情况下,混合碳四液化气的催化裂解反应主要发生在丁烯分子上,丙烯的最高选择性可达60%,丙烯和乙烯的总选择性可达80%.

By impregnating sodium ion onto nano-sized HZSM-5 zeolite and carrying out the catalytic cracking of C4 liquefied petroleum gas （LPG） over the modified catalysts in a small fixed-bed reactor, the effect of catalyst acidity on the selectivity of the catalytic cracking was investigated. Results show that, impregnating with sodium ions can selectively eliminate the strong acid sites of the nano-sized zeolite. In the condition of all the strong acid sites of the nano-sized zeolite being killed by sodium ions, only butenes in the C4 LPG undergo catalytic cracking, which gives the highest propytene selectivity of about 60%. The total selectivity to ethylene and propylene amounts to about 80%.