Modified HZSM-5 as FCC additive for enhancing light olefins yield from catalytic cracking of VGO
Modified HZSM-5 as FCC additive for enhancing light olefins yield from catalytic cracking of VGO
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DOI：
10.1016/j.apcata.2014.03.021
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发表时间：
2014-05-05
影响因子：
5.5
通讯作者：
Al-Khattaf, S.
中科院分区：
文献类型：
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作者：
Awayssa, O.;Al-Yassir, N.;Al-Khattaf, S.
用Mn和碱处理对不同Si/Al-2比的HZSM-5进行改性，并将其用作FCC催化剂添加剂，以提高加氢处理的阿拉伯轻质减压瓦斯油（VGO）催化裂化的低碳烯烃（特别是丙烯）产率。Mn/HZSM-5和碱处理的HZSM-5添加剂的性能使用商业平衡USY FCC催化剂（E-Cat）在固定床微活性测试装置中在550 ℃和各种催化剂/油比下评估。对于30、80和280的Si/Al-2，在含母体HZSM-5的E-Cat上的轻质烯烃产率分别增加到18.1、25.4和27.4重量%，相比之下，在E-Cat上的轻质烯烃产率为15.4重量%（在75重量%转化率下）。Mn改性的HZSM-5分子筛作为添加剂，可进一步提高低碳烯烃产率。在E-Cat-Mn/HZSM-5（Si/Al-2 = 80，2.0wt%Mn）上实现了29.2wt%的最高轻质烯烃产率。Mn/HZSM-5催化剂提高低碳烯烃产率的主要原因是降低了ZSM-5分子筛的酸密度和强酸中心的数量，并可能使ZSM-5分子筛的孔径局部变窄。碱处理的HZSM-5也表现出较高的轻烯烃产率相比，母体HZSM-5，由于形成分级微台面拓扑结构。在含E-Cat碱处理的HZSM-5（Si/Al-2 = 80-280，使用适当的脱硅条件）上获得类似于28.3wt%的最高轻质烯烃产率。(C)© 2014 Elsevier B. V.保留所有权利。
HZSM-5 with varying Si/Al-2 ratios were modified with Mn and alkaline treatment and tested as FCC catalyst additives to enhance the yield of light olefins (in particular, propylene) from catalytic cracking of hydrotreated Arab Light vacuum gas oil (VGO). The performance of the Mn/HZSM-5 and alkaline treated HZSM-5 additives were assessed using a commercial equilibrium USY FCC catalyst (E-Cat) in a fixed-bed micro-activity test unit at 550 degrees C and various catalyst/oil ratios. The yield of light olefins over E-Cat containing parent HZSM-5 increased to 18.1, 25.4 and 27.4 wt% for Si/Al-2 of 30, 80 and 280, respectively, compared with 15.4 wt% over E-Cat (at 75 wt% conversion). Further increase in light olefins yield was achieved upon using Mn modified HZSM-5 as an additive. The highest light olefins yield of 29.2 wt% was achieved over E-Cat-Mn/HZSM-5 (Si/Al-2 = 80, 2.0 wt% Mn). The enhanced production of light olefins over the Mn/HZSM-5 additive is mainly attributed to the decrease in the acid density and the amount of strong acid sites, and (possibly) the partial narrowing of ZSM-5 micropore. Alkaline treated HZSM-5 also exhibited high light olefins yield compared with parent HZSM-5, due to the formation of hierarchical micro-mesa topology. The highest light olefins yield of similar to 28.3 wt% was obtained over E-Cat-containing alkaline treated HZSM-5 (Si/Al-2 = 80-280, using the appropriate desilication conditions). (C) 2014 Elsevier B.V. All rights reserved.