γ-Al2O3 supported Co-W based catalysts with varying Co (1 - 3 wt %) and W (7 - 13 wt %) loadings were prepared using impregnation and sonochemical methods. All prepared catalysts were characterized with elemental analysis, BET analysis, X-ray diffraction (XRD), NH3 temperature programmed desorption (TPD), temperature programmed reduction (TPR) and thermogravimetry analysis (TGA). <p>The performances of all the synthesized catalysts were tested at a pressure of 8.9 MPa, LHSV of 2 h-1 and temperatures of 340, 350 and 360 °C in a laboratory trickle bed microreactor for hydrodesulphurization (HDS) and hydrodenitrogenation (HDN) of light gas oil (LGO) derived from Athabasca bitumen. The performance tests with impregnated catalysts indicated a maximum in activity for HDS and HDN reactions (sulfur and nitrogen conversions at 93.0 and 57.1 % at 360 °C) for Co(3 wt %)-W(10 wt %)/γ-Al2O3 whereas the performance tests with sonochemically prepared catalysts showed a maximum in activity (sulfur and nitrogen conversions at 87.9 and 42.5 % at 360 °C) for Co(3 wt %)-W(11.5 wt %)/ γ-Al2O3. These two catalysts were selected for detail performance, optimization and kinetic studies. The effects of reaction temperature (340 - 380 °C), pressure (7.6 - 10.3 MPa), liquid hourly space velocity (1.5 - 2.0 h-1) and hydrogen gas/gas oil ratio (400 - 800 mL/mL) were examined on HDS and HDN of LGO with these catalysts. The reaction kinetics for HDS was best fitted with a Power Law model whereas same for HDN was found to be best represented by a Langmuir-Hinshelwood model with a reasonable accuracy (0.90 <R2 <0.95). The activation energy for HDS of LGO were 14 and 12 kJ/mol for selected impregnated and sonochemically prepared catalysts whereas the same for HDN were 9 and 14 kJ/mol for these catalysts, respectively.
Calculation showed that the fitted HDS rate expressions were apparent and HDN rate expressions were intrinsic under existing reaction conditions. It also showed that the pore diffusion resistances for both HDS and HDN increased with an increase in reaction temperature from 340 to 380 °C.
| Identifer | oai:union.ndltd.org:USASK/oai:usask.ca:etd-01292007-115806 |
| Date | 30 January 2007 |
| Creators | Vishwakarma, Santosh Kumar |
| Contributors | Dalai, Ajay K. |
| Publisher | University of Saskatchewan |
| Source Sets | University of Saskatchewan Library |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-01292007-115806/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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