Effect of cyclohexane as hydrogen-donor in ultradispersed catalytic upgrading of heavy oil
Effect of cyclohexane as hydrogen-donor in ultradispersed catalytic upgrading of heavy oil
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DOI：
10.1016/j.fuproc.2015.07.016
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发表时间：
2015-10-01
影响因子：
7.5
通讯作者：
Wood, Joseph
中科院分区：
文献类型：
--
作者：
Hart, Abarasi;Lewis, Charlotte;Wood, Joseph
在趾部到跟部空气注入（THAI）工艺中引入催化剂以增强井下改质受到由于重油裂化引起的焦化而导致的失活的限制。本研究旨在减少重油改质过程中可能出现的催化剂失活问题。超分散的催化剂颗粒可以潜在地替代丸状催化剂，丸状催化剂在THAI操作期间一旦失活就可能难以再生。分散的颗粒可以潜在地一次通过井下应用于重油的原位改质。所研究的催化剂是细粉碎的粒状Ni-Mo/Al 2 O 3催化剂（2.4 μ m）。液体、焦炭和气体的产物分布可受促进加氢转化反应而不是简单裂化的合适的加氢源的存在的影响。为了提高液体产率，同时抑制焦炭形成，环己烷作为氢供体溶剂的效果进行了研究，在搅拌间歇式反应器（100毫升），温度425摄氏度，初始压力175巴，搅拌500 rpm，和一个短的反应时间为10分钟。环己烷的使用进行了评估，对氢气。与相同条件下的氮气环境相比，在氢气气氛下的反应显著降低了焦炭产率41.3%。此外，相对于4.67wt.%，随着环己烷：油比从0.01增加到0.08（g.g（-1）），焦炭减少62-45.4%。在氮气环境下的超分散催化改质中在不添加环己烷的情况下观察到的焦炭的量随着环己烷：油比的增加，所产生的油API比重和中间馏分（200-343 ℃）增加，同时粘度降低。发现估计的0.073 CH：油比以类似于在相同条件下在氢气气氛下升级的方式抑制焦炭形成。(C)2015作者出版社：Elsevier B. V.
The incorporation of catalysts to enhance downhole upgrading in the Toe-to-Heel Air Injection (THAI) process is limited by deactivation due to coking arising from the cracking of heavy oil. This study aims to reduce the catalyst deactivation problems that can occur with upgrading of heavy oils. Ultradispersed catalyst particles could potentially replace pelleted catalysts which may be difficult to regenerate once deactivated during the THAI operation. The dispersed particles could potentially be applied once through, down-hole for in situ upgrading of heavy oil. The catalyst studied was finely crushed pelleted Ni-Mo/Al2O3 catalyst (2.4 mu m). The product distribution of liquid, coke and gas may be influenced by the presence of a suitable hydrogemsource which promotes hydroconversion reactions rather than simple cracking. In order to improve liquid yield whilst suppressing coke formation, the effect of cyclohexane as hydrogen-donor solvent was studied in a stirred batch reactor (100 mL) at temperature 425 degrees C, initial pressure 175 bar, agitation 500 rpm, and a short reaction time of 10 min. The use of cyclohexane was evaluated against that of hydrogen gas. The reaction under hydrogen atmosphere significantly reduced coke yield by 41.3% compared with a nitrogen environment under the same conditions. Also, the coke decreased by 62-45.4% as the cyclohexane:oil ratio increased from 0.01 to 0.08 (g.g(-1)) relative to 4.67 wt.% of coke observed without added cyclohexane in ultradispersed catalytic upgrading under nitrogen environment As the cyclohexane:oil ratio increases, the produced oil API gravity and middle distillate fractions (200-343 degrees C) increase whilst the viscosity decreases. An estimated 0.073 CH:oil ratio was found to suppress coke formation in a similar manner to upgrading under hydrogen atmosphere at the same conditions. (C) 2015 The Authors. Published by Elsevier B.V.