KAMAL K PANT
Articles written in Journal of Chemical Sciences
Volume 129 Issue 11 November 2017 pp 1705-1711 REGULAR ARTICLE
Molybdenum impregnated zeolite catalyst has been well-known for methane conversion into higher hydrocarbons under non-oxidative condition. HZSM-5 & HMCM-22 zeolites are the effective supports for this purpose. However, the catalytic performance of HMCM-22 supported molybdenum catalyst is consideredsuitable than that for HZSM-5 catalyst with high aromatic selectivity due to unique pore structure and framework of MCM-22 zeolite support. Effect of Mo loading over MCM-22 zeolite has been studied for the activity test and observed that 5 wt% metal content over the support (MCM-22) is optimum for the proper tuning of acidic & metallic sites of the catalyst. Effect of silica/alumina ratio (SAR, molar) of MCM-22 zeolite has also been studied and observed that lower SAR (30) is suitable (C₆H₆ selectivity, 37%) comparatively to higher SAR (55)(C₆H₆ selectivity, 18%). Lower GHSV (720 mL/g.h) is effective for higher hydrocarbon production compared to higher GHSV (1200 mL/g.h) due to low residence time. Mo/MCM-22 catalysts with different Mo loading werecharacterized by BET surface area, XRD, Raman spectroscopy and NH₃-TPD analysis. Unique pore systems [10 & 12 membered ring (MR)] and framework of MCM-22 zeolite support are the key factors for effective methane conversion to value added chemicals when loaded with molybdenum.
Volume 129 Issue 11 November 2017 pp 1747-1754 REGULAR ARTICLE
Application of Fischer-Tropsch synthesis (FTS) in the utilization of low H ₂/CO ratio (0.5–1.5) gas obtained from coal and biomass gasification can be done by selecting a catalyst system active for both FTS and WGS reaction. The enhancement of H ₂ content depends on the extent of water gas shift (WGS) reaction and can be quantified by measuring usage ratio define as a mole of H₂ to CO converted. With an attempt to utilize low H ₂/CO ratio syngas bimetallic (Fe/Co/SiO ₂) were prepared and compared with monometallic (Fe/SiO ₂ and Co/SiO ₂) catalysts. The catalysts were tested in fixed bed reactor at industrial relevant FTS conditions(T: 220−260 ◦C, P: 2.0 MPa, GHSV-1.2 SL/gcat-h, H ₂/CO: 1–1.5). The incorporation of Fe-Co bimetallic catalyst facilitates both FT and WGS reaction because of the presence of iron and cobalt phases. Compared to monometallic catalyst there is a significant increase in CO conversion over the bimetallic catalyst. Also, the yield of C ₅+ was significantly higher over bimetallic catalyst compared to iron catalyst, where olefin was the major product. Selected catalyst (Fe/Co/SiO ₂) was tested for their activity toward WGS reaction. Effects of temperature, pressure, and feed composition on WGS reaction over bimetallic catalyst were studied. Lower value usage ratio (1.62 and 1.58) reveals the occurrence WGS reaction Fe-Co bimetallic catalyst at 240 ◦C and 260 ◦C. At 240 ◦C, 72% CO conversion, and 60% C ₅ + selectivity show that the catalyst efficiently utilizes the increased H ₂/CO ratio in the production of liquid hydrocarbon.
Volume 130 Issue 6 June 2018 Article ID 0064
Effect of reaction conditions were investigated for Fischer-Tropsch (FT) synthesis process over Fe/Cu/K./SiO2 catalyst for maximization of a selective range of liquid hydrocarbon (C5−20). Operating conditions of the reaction have a strong impact on the activity and selectivity of the process. The parametersthat influence the FT synthesis reaction and product distribution include the reactor temperature, pressure,space velocity, the H2/CO molar ratio in the feed syngas and the catalyst. Experiments were performed at varying range of temperature, pressure, Space velocity and H2/CO molar ratio. Variation inC5+ selectivity and (olefin/paraffin) O/P ratio were observed and analyzed to select the optimum values. Reaction conditions affect the H2and CO surface coverage and re-adsorption of olefins which play a crucial role in altering overall product selectivity. Reaction rates for FT and water gas shift (WGS) reactions were compared at different conditions. At optimum conditions, CO conversion and C5+ selectivity were 45.9% and 77.4%, respectively.
Volume 134, 2022
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