Coupling Process of Heavy Oil Millisecond Pyrolysis and Coke Gasification: A Fundamental Study

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• 作者：Jinhong Zhang ; Yuanjun Che ; Zhenbo Wang ; Yingyun Qiao ; Yuanyu Tian
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：August 18, 2016
• 年：2016
• 卷：30
• 期：8
• 页码：6698-6708
• 全文大小：561K
• 年卷期：0
• ISSN：1520-5029

文摘

To realize the clean and high-efficiency utilization of the inferior heavy oil, a novel conceptional process coupling heavy oil millisecond pyrolysis and coke gasification processes was proposed. The effects of reaction temperature and residence time on the flash pyrolysis behavior of vacuum residue (VR) were first investigated using Py-GC/TOF-MS. Results show that increasing the reaction temperature from 600 to 800 °C, as well as shortening the residence time from 400 to 200 ms could reduce the coke yield by approximately 28%. 1-Alkenes are the most abundant class in the cracked products, and the selectivity of total olefins in the light products from C₃ to C₁₆ could be over 75%. Then the cracking performance of VR over Y zeolite-based equilibrium FCC catalysts, silica sands, and calcium aluminate catalysts were studied by a fluidized bed reactor. Furthermore, the coked catalysts were gasified in steam and steam–O₂ mixture atmosphere, respectively. Results show that the calcium aluminate catalyst has appropriate cracking activity, excellent light olefin selectivity, significant coke gasification activity, and good hydrothermal stability. The feed conversion can be up to approximately 98 wt% at 650 °C, with 70% light olefin selectivity in the cracking gas, while the coke yield is only 6.4 wt% in the pyrolysis of VR with a 16 wt% Conradson carbon residue. Moreover, the calcium aluminate catalyst could reduce the gasification temperature and increase the coke gasification efficiency and the hydrogen content of syngas. These studies demonstrate that directly processing inferior heavy oil in the coupling process using calcium aluminate catalyst is feasible.