摘要
采用等体积浸渍法制备Pt-Sn/γ-Al2O3催化剂,并使用KNO3或KCl对其进行改性制备Pt-Sn-K/γ-Al2O3催化剂。采用固定床反应器,在580℃、0.1MPa、氢气/异丁烷体积比2、进料总空速2000h-1（异丁烷空速667h-1）条件下,评价催化剂的异丁烷脱氢催化性能。同时,使用XRD、压汞法、CO2-TPD和O2-TPO对催化剂进行表征。结果表明,KNO3改性的Pt-Sn-K/γ-Al2O3催化异丁烷脱氢反应的转化率和异丁烯收率均高于KCl改性的Pt-Sn-K/γ-Al2O3催化剂,但其异丁烯选择性却略低于后者;随着Pt-Sn-K/γ-Al2O3中K负载量的增加,其催化异丁烷脱氢反应的转化率降低,异丁烯选择性则逐渐增加,异丁烯收率呈现先增加后减小的趋势,合适的K质量分数在0.4%~0.8%范围。Pt-Sn-K/γ-Al2O3催化剂中的Pt、Sn和K处于高度分散状态或者含量很少;钾盐的掺入未对催化剂孔体积和平均孔半径产生大的影响;催化剂表面存在弱碱中心和强碱中心,后者对催化异丁烷脱氢反应更有利。
Pt-Sn/7-Al2O3 catalyst was prepared by incipient impregnation, and then modified by KNO3 or KC1 to form the Pt-Sn-K/γ-Al2O3 catalyst. The catalytic performance of the prepared Pt-Sn-K/γ-Al2O3 for isobutane dehydrogenation was evaluated under the condition of 580℃, 0.1 MPa, φ（H2 ）/φ（i-C4 H10 ） = 2, total feedstock GHSV= 2000 h-1 （GHSV（i-C4 H10 ） = 667 h^-1 ） in a fixed bed reactor. Meanwhile, the catalysts were characterized by means of XRD, mercury intrusion porosimetry, CO2-TPD and O2-TPO. The results showed that both the conversion and isobutene yield of isobutane dehydrogenation catalyzed by the Pt-Sn-K/γ-Al2O3 modified by KNO3 were higher and isobutene selectivity was somewhat lower than that of modified by KC1. The conversion of isobutene dehydrogenation reduced with the increase of potassium content in Pt-Sn-K/γ-Al2O3, while the isobutene selectivity increased, the isobutene yield first increased and then decreased as a composite result. The appropriate potassium content of Pt-Sn-K/γ-Al2O3 for isobutane dehydrogenation was in the range of 0.4 %-0.8 %. Pt, Sn and K were highly decentralized or had a very little amount in Pt-Sn-K/γ-Al2O3. The addition of potassium into Pt-Sn/γ-Al2O3 had very little impact on the pore volume and average pore radius of the catalyst. There existed both weak and strong base sites on the surface of Pt-Sn-K/γ-Al2O3, and the latter might promote the isobutane dehydrogenation.
出处
《石油学报（石油加工）》
EI
CAS
CSCD
北大核心
2015年第4期869-874,共6页
Acta Petrolei Sinica(Petroleum Processing Section)
关键词
异丁烷
不同钾盐
改性
负载型催化剂
脱氢性能
isobutane
different potassium salt
modification
supported catalyst
dehydrogenation performance
