Title: Methane conversion to higher hydrocarbons over copper loaded BZSM-5 in the presence of oxygen

Authors: Ramli Mat; Mahadhir Mohamed; Anwar Johari; Asmadi Ali

Addresses: Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, Skudai, 81310 Johor Bahru, Malaysia. ' Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, Skudai, 81310 Johor Bahru, Malaysia. ' Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, Skudai, 81310 Johor Bahru, Malaysia. ' Department of Engineering Science, Faculty of Science and Technology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia

Abstract: The direct conversion of methane to higher hydrocarbons either over metal catalyst or zeolite has not been successful so far in achieving the methane conversion with higher hydrocarbons selectivity within the economic range due to oxidation of the product. The present research aims at improving the performance of BZSM-5 catalyst with the addition of copper. Catalytic behaviours at different reaction conditions were investigated. Reaction temperature, oxygen concentration, copper loading and space velocity have been identified as the contributing factors in methane conversion and higher hydrocarbon selectivity. Methane conversion is favourable at higher temperatures which shows 78% conversion at 900°C. The selectivity of C₅⁺ hydrocarbons increases from 650°C up to 800°C, but decreases slightly soon after. In methane conversion, the initial step involves an activation of methane to form CH₃^* free radicals via concerted actions between copper species and acid sites. CH₃^* radicals react in the gas phase to form C₂⁺. The formation of CO_x was derived from the secondary reaction of the CH₃^* radicals with metal oxide catalyst or complete combustion of C₂⁺ products. The formation of CO_x was reduced at low oxygen concentration and short residence time. [Received: January 31, 2011; Accepted on June 3, 2011]

Keywords: methane conversion; oligomerisation; zeolite; acidity; natural gas; hydrocarbons; reaction temperature; oxygen concentration; copper loading; space velocity; catalytic behaviour.

DOI: 10.1504/IJOGCT.2011.043717

International Journal of Oil, Gas and Coal Technology, 2011 Vol.4 No.4, pp.356 - 374

Published online: 29 Jan 2015 *

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