Effectiveness of Different Transition Metal Dispersed Catalysts for In Situ Heavy Oil Upgrading
Effectiveness of Different Transition Metal Dispersed Catalysts for In Situ Heavy Oil Upgrading
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DOI：
10.1021/acs.iecr.5b02953
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发表时间：
2015-11-04
影响因子：
4.2
通讯作者：
Wood, Joseph
中科院分区：
文献类型：
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作者：
Al-Marshed, Abdullah;Hart, Abarasi;Wood, Joseph
据报道，用于原位催化升级的粒径小于100 nm的超分散粒子的性能优于通过将造粒炼油厂催化剂加入到脚趾到脚跟空气注入(TAI)工艺的水平生产井中实现的强化催化升级。重油的加氢转化是在搅拌间歇反应器中进行的，反应温度为425℃，压力为50bar(氢气初始压力)，转速为900rpm，反应时间为60min，使用了一系列无载体过渡金属(Mo、Ni和Fe)催化剂。从产品分布、物理性能和产品质量三个方面评价了金属纳米颗粒(NPs)的效果。并对生产的焦炭和回收的催化剂进行了研究。与单独的热裂化(24度API和53.5 CP)相比，使用NPs观察到的升级油的API重力和粘度水平约为21度API和108 CP；使用NPs进行适度升级是由于缺乏沸石、氧化铝或二氧化硅等载体提供的裂化功能。然而，研究发现，分散纳米颗粒的存在显著地抑制了焦炭的形成：4.4wt%(MoS_2)、5.7wt%(NiO)和6.8wt%(Fe_2O_3)，而单独热裂解得到的焦炭质量分数为12wt%。结果还表明，随着分散的无担载金属纳米颗粒以硫化物的形式存在，改质油的中间馏分(177-343℃)得到了改善，尤其是MoS2，相对于43wt%(热裂解)和28wt%(原料油)，MoS2的SOwt%。Fe_2O_3和NiO的中间馏分产率分别为47wt%和49wt%。因此，铁和镍基无载体NPs的活性与MoS2的活性相似。与镍和钼催化剂相比，铁基催化剂用于重油改质的成本和可用性是其优势，这可能证明了它的偏好。X-射线衍射仪和扫描电子显微镜分析表明，与热裂解制得的喷射型焦炭相比，在改质过程中引入分散型催化剂有利于生产可用作工业燃料的海绵型焦炭。
Ultradispersed particles of a size less than 100 nm for in situ catalytic upgrading have been reported to outperform the augmented catalytic upgrading achieved by incorporating pelleted refinery catalyst to the horizontal production well of the toe-to-heel air injection (THAI) process. Hydroconversion of heavy oil was carried out in a stirred batch reactor at 425 degrees C, 50 bar (initial H-2 pressure), 900 rpm, and 60 min reaction time using a range of unsupported transition metal (Mo, Ni, and Fe) catalysts. The effect of metal nanoparticles (NPs) was evaluated in terms of product distribution, physical properties, and product quality. The produced coke and recovered catalysts were also studied. The levels of API gravity and viscosity of the upgraded oils observed with the NPs was approximately 21 degrees API and 108 cP compared with thermal cracking alone (24 degrees API and 53.5 cP); this moderate upgrade with NPs is due to the lack of cracking functionality offered by supports such as zeolite, alumina, or silica. However, it was found that the presence of dispersed NPs significantly suppressed coke formation: 4.4 wt % (MoS2), 5.7 wt % (NiO), and 6.8 wt % (Fe2O3) compared to 12 wt % obtained with thermal cracking alone. The results also showed that with dispersed unsupported metal NPs in sulfide form the middle distillate (177-343 degrees C) of the upgraded oil was improved, particularly with MoS2, which gave SO wt % relative to 43 wt % (thermal cracking) and 28 wt % (feed oil). The middle distillate yields for Fe2O3 and NiO are 47 and 49 wt %, respectively. Hence, iron and nickel-based unsupported NPs showed similar activity when compared to the activity of MoS2. The cost and availability of iron-based catalysts compared to those of Ni and Mo for heavy oil upgrading are advantages that may justify its preference. Furthermore, the X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses showed that introducing dispersed catalysts to the upgrading helped to produce sponge-type coke that could be used as industrial fuel compared to shot-type obtained upon thermal cracking.