Current Science

Sudip Maity ¹, Olusola O. James ¹, Biswajit Chowdhury ², Aline Auroux ³

Affiliations
1 Liquid Fuels Section, Central Institute of Mining and Fuels Research (DC), Dhanbad 828 108, IN
2 Applied Chemistry Department, Indian School of Mines, Dhanbad 828 108, IN
3 Institute de Rechereches sur la Catalyse et l’Environnement de Lyon, UMR 5256, CNRS/Universite Lyonl, FR

Abstract

The present study reports the possibility of using copper as a low-cost reduction promoter in cobaltbased Fischer-Tropsch (FT) catalysts. Adsorption behaviour of CO and H₂ on alumina-supported Co and Co-Cu catalysts has been examined. Amount of CO and H₂ desorption and temperature of desorption are used to gain insights about the performance of the catalysts. Presence of Cu alters CO and H₂ adsorption on Co-alumina catalyst. Modification of alumina with Ca enhances Co dispersion and the amount of CO adsorbed. However, increase in the amount of CO adsorbed does not translate into increase in CO conversion. The Co-Cu-based catalysts display higher amount of H₂ adsorbed and higher CO desorption temperature. The latter is at the expense of the amount of CO adsorbed for low CO conversion resulting in lower activity for FT synthesis. The catalysts display high selectivity towards oxygenates. The high CO adsorption strength on Co-Cu-based catalysts is rationalized in terms of synergistic interaction of CO with cobalt particles through carbon atom and copper particles through oxygen atom.

Keywords

Adsorption, Alumina, Copper–Cobalt Catalysts, Desorption.

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Prabal Boral ¹, Atul K. Varma ², Sudip Maity ¹

Affiliations
1 Central Institute of Mining and Fuel Research, PO: FRI, Dhanbad 828 108, IN
2 Indian School of Mines, Dhanbad 826 004, IN

Abstract

In order to study the X-ray structural parameters, five coals have been chosen from different coal basins of India. These coals have been demineralized by standard HF + HCl treatment and treated with nitric acid in aqueous and glacial acetic acid media. X-ray diffraction (XRD) patterns of the samples are recorded using a slow step scan (2 s/step) over an angular range 2θ ∼ 10-90°. TOPAS software has been used to determine the structural parameters like interlayer spacing (d₀₀₂), crystallite size (L_c), aromaticity (f_a) and average number of aromatic layers (N_c). The structural parameters have been correlated with chemical as well as petrographic parameters of coals. Mean random reflectance (MR_r) of the studied coals varies between 0.44% and 0.54% and the vitrinite, liptinite and inertinite contents vary between 17.8% and 66.4%, 9.2% and 20.3% and 20.7% and 62.9% respectively. Nitration in both the media has increased d₀₀₂ values. This study also shows that d₀₀₂ and fa values are dependent on the rank of the coal, rather than only the carbon content (C_dmf, dry mineral free basis). XRD rank parameter values have been directly correlated with the petrographic rank parameters. Nitration in both the media has induced similar kind of effect on individual macerals. Behaviour of the macerals to chemical treatment is also reported in this study.

Keywords

Coal, Maceral, Nitration, Rank, XRD Parameters.

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