Effect of Aromatics on Deep Hydrodesulfurization of Dibenzothiophene and 4,6-Dimethyldibenzothiophene over NiMo/Al2O3 Catalyst
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- 作者：Tao Song ; Zisheng Zhang ; Jinwen Chen ; Zbigniew Ring ; Hong Yang ; Ying Zheng
- 刊名：Energy & Fuels
- 出版年：2006
- 出版时间：November 2006
- 年：2006
- 卷：20
- 期：6
- 页码：2344 - 2349
- 全文大小：199K
- 年卷期：v.20,no.6(November 2006)
- ISSN：1520-5029
文摘
The influence of different aromatics on the deep hydrodesulfurization (HDS) of dibenzothiophene (DBT)and 4,6-dimethyldibenzothiophene (4,6-DMDBT) over a commercial NiMo/
-Al2O3 hydrotreating catalystwas investigated in a fixed-bed multiphase microreactor under designed conditions. Both the sulfur-containingcompounds and the aromatic compounds in feeds and hydrotreated products were identified and quantified byGC-AED. Catalyst deactivation was observed, and a simple model for it was established. The kinetic behaviorof these model compounds was studied with an assumption of pseudo-first-order reaction kinetics. The rateconstants and the corresponding activation energies were determined, and the heat of adsorption for eachcompound on the catalyst surface was computed by density functional theory using the Material Studio software.The HDS rate for 4,6-DMDBT was much lower than that for DBT, which is attributed to the steric hindranceof the methyl groups at the 4 and 6 positions. The apparent activation energy of 4,6-DMDBT was higher thanthat of DBT under the same conditions. TThe HDS reaction rate significantly decreased with an increase ofthe content of aromatics in the feed. Aromatics with 2 or more rings were found to have stronger retardanteffect on HDS than monoaromatics. This adverse effect was more pronounced for 4,6-DMDBT than for DBT.The competitive adsorption between the sulfur compounds and aromatics on the catalyst surface was the mainreason for the decreased HDS efficiency as qualitatively verified by the heat of adsorption data.
-Al2O3 hydrotreating catalystwas investigated in a fixed-bed multiphase microreactor under designed conditions. Both the sulfur-containingcompounds and the aromatic compounds in feeds and hydrotreated products were identified and quantified byGC-AED. Catalyst deactivation was observed, and a simple model for it was established. The kinetic behaviorof these model compounds was studied with an assumption of pseudo-first-order reaction kinetics. The rateconstants and the corresponding activation energies were determined, and the heat of adsorption for eachcompound on the catalyst surface was computed by density functional theory using the Material Studio software.The HDS rate for 4,6-DMDBT was much lower than that for DBT, which is attributed to the steric hindranceof the methyl groups at the 4 and 6 positions. The apparent activation energy of 4,6-DMDBT was higher thanthat of DBT under the same conditions. TThe HDS reaction rate significantly decreased with an increase ofthe content of aromatics in the feed. Aromatics with 2 or more rings were found to have stronger retardanteffect on HDS than monoaromatics. This adverse effect was more pronounced for 4,6-DMDBT than for DBT.The competitive adsorption between the sulfur compounds and aromatics on the catalyst surface was the mainreason for the decreased HDS efficiency as qualitatively verified by the heat of adsorption data.