摘要
采用分级改性的方法制备Zn-ZSM-5/Pt-L核壳型双金属催化剂,通过改变金属负载量的组配方式对催化剂表面酸性进行调控,利用X射线衍射(XRD)、氮气吸附脱附、氨气程序升温脱附(NH3-TPD)、吡啶吸附-原位傅里叶变换红外光谱(Py-FTIR)等手段进行表征,并以正戊烷为原料对催化剂的轻烃芳构化性能进行评价。结果表明,在复合分子筛核壳结构的基础上,分级引入双金属的改性方式有效地调控了催化剂表面的酸分布以及L/B酸比例,使双金属催化剂更好地发挥L酸和B酸的协同催化作用,当Zn和Pt负载量分别为1.0%和0.6%时所表现出的催化性能最优,其正戊烷芳构化反应的转化率为99.1%、芳烃选择性达到47.2%。
The core-shell composite zeolite Zn-ZSM-5/Pt-L was prepared via step-by-step modification. The surface acidity was regulated by changing the ratio of two metals. The physical and chemical properties were investigated by X-ray diffraction (XRD), N2 adsorption-desorption, ammonia tempera- ture-programmed desorption (NH3-TPD) and in situ Py-FTIR spectroscopy. The light hydrocarbon aromatization performance of catalysts was evaluated using n-pentane as the raw material. The results exhibit that the modification of introducing active metal step-by-step effectively regulates the L/B acid ratio and distribution on the catalyst surface, which could cause more excellent synergism between B acid and L acid. At the loading of Zn and Pt metal of 1.0% and 0.6%, respectively, the catalytic performance reaches the best. The conversion rate of pentane is 99.1% and aromatic selectivity is up to 47.2%.
出处
《石油炼制与化工》
CAS
CSCD
北大核心
2015年第7期67-72,共6页
Petroleum Processing and Petrochemicals
基金
国家自然科学基金项目(20976077
21076100)
国家重点基础研究发展规划(973)项目(2007CB216403)
中国石油天然气股份有限公司合同项目(10-01A-01-01-01)