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Two-Step Thermal Cracking of an Extra-Heavy Fuel Oil: Experimental Evaluation, Characterization, and Kinetics
Industrial & Engineering Chemistry Research ( IF 4.2 ) Pub Date : 2018-05-24 , DOI: 10.1021/acs.iecr.8b00819
Mohammad Ghashghaee 1 , Samira Shirvani 1
Affiliation  

This work deals with an efficient two-step thermal upgrading process for converting extra-heavy fuel oil to light olefins (ethylene, propylene, and butenes) and fuels (gasoline and diesel fuel). In the first step, mild thermal pretreatment was implemented at different temperatures (360–440 °C) in the liquid phase to obtain a more suitable feedstock for an olefin production unit. Thanks to this cost-effective pretreatment, the upgraded feedstock demonstrated considerable flowability and crackability compared to the initial fuel oil, making the subsequent vapor-phase operation easier to handle at temperatures as high as 800 °C with no severe operational impediments. The quantitative 1H and 13C NMR studies shed light on the enhanced features of the thermally treated feedstock toward lighter and more valuable products. As a result, remarkable olefin production (74.7 or 55.1 wt % light olefins based on the upgraded or the original feedstock) was accomplished in this two-step process. The process could be alternatively stopped at the first stage for maximum liquid fuels (69.3 wt %) with gasoline as the larger constituent. The detailed kinetic investigations of the thermal decomposition of the feedstock using several reliable approaches revealed that the activation energy predictions (42.3–272.9 kJ/mol) by the Kissinger–Akahira–Sunose method almost perfectly matched the trend of a reference Starink model over the whole range of conversion. All model-free methods correlated with a coefficient of determination above 97.9%. Avrami’s theory was further applied to determine the reaction order, and the values were slightly smaller than those from a five-lump kinetic model of the semibatch operation. However, the apparent activation barrier in the reactor was in good correspondence with the range from the microscale nonisothermal decomposition.

中文翻译:

超重燃料油的两步热裂解:实验评估,表征和动力学。

这项工作涉及有效的两步热升级过程,该过程可将超重燃料油转化为轻质烯烃(乙烯,丙烯和丁烯)和燃料(汽油和柴油燃料)。第一步,在液相中不同温度(360–440°C)下进行温和的热预处理,以获得更适合于烯烃生产装置的原料。由于采用了这种具有成本效益的预处理方法,与最初的燃料油相比,这种提质后的原料显示出了可观的流动性和易裂化性,从而使后续的气相操作更容易在高达800°C的温度下进行,而没有严重的操作障碍。定量1 H和1313 C NMR研究揭示了经过热处理的原料向更轻,更有价值的产品的增强特性。结果,在该两步方法中完成了显着的烯烃生产(基于经升级的原料或原始原料的74.7或55.1重量%的轻质烯烃)。对于以汽油为主要成分的最大液体燃料(69.3 wt%),该过程也可以在第一阶段停止。使用几种可靠的方法对原料进行热分解的详细动力学研究表明,基辛格—阿卡希拉—桑索斯方法的活化能预测值(42.3–272.9 kJ / mol)几乎与整个参考Starink模型的趋势完全吻合转换范围。所有无模型方法的测定系数均高于97.9%。Avrami理论进一步用于确定反应顺序,其值比半间歇操作的五集动力学模型的值小。然而,反应器中的表观活化势垒与微量非等温分解的范围高度对应。
更新日期:2018-05-25
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