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Carbon cycle: capture and activation of carbon dioxide using hydrotalcites

Alsamaq, Suzanne (2012)
Ph.D. thesis, University of Birmingham.

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Abstract

Dry Reforming of methane (DRM) was performed successfully over hydrotalcite catalysts (A) Ni\(^2\)\(^+\)/Mg\(^2\)\(^+\)/Al\(^3\)\(^+\), (B) Ni\(^2\)\(^+\)/Mg\(^2\)\(^+\)/Al\(^3\)\(^+\)/Fe\(^3\)\(^+\), (C) Ni\(^2\)\(^+\)/Co\(^2\)\(^+\)/Al\(^3\)\(^+\) and (D) Ni\(^2\)\(^+\)/Co\(^2\)\(^+\)/Al\(^3\)\(^+\)/Fe\(^3\)\(^+\). The highest conversions for CH\(_4\) and CO\(_2\) were 85% and 75% respectively, achieved at 750°C, CO\(_2\)/CH\(_4\) ratio of 1.50 with a residence time of 2.4 seconds over catalyst B. Activation energy was calculated for the DRM reaction of 81.5 kJ mol\(^-\)\(^1\). A coke formation study showed that catalyst B formed the lowest weight percentage of coke at around 10 ± 4 (wt%) after 5 hours of reaction.

Adsorption capacity of CO\(_2\) into hydrotalcite was tested in TGA and a fixed bed reactor. Adsorbent B displayed the highest adsorption capacity of CO\(_2\) compared to the rest of the adsorbents. CO\(_2\) capacities of 0.53 mmol g\(^-\)\(^1\) over calcined powdered adsorbent B and 0.41 mmol g\(^-\)\(^1\) upon the pellets were recorded using TGA. The capacity dropped to 0.30 mmol g\(^-\)\(^1\) when subjected to a dilute CO\(_2\) in He flow in the fixed bed reactor. Powdered amine (N2)-modified HTlcs showed a CO\(_2\) adsorption capacity of 2.38 mmol g\(^-\)\(^1\) measured using TGA. The best adsorption capacity of CO\(_2\) over tablets was with amine (N2)-modified HTlcs in a fixed bed reactor at 2.85 mmol g\(^-\)\(^1\).

Type of Work:Ph.D. thesis.
Supervisor(s):Wood, Joseph and Al-Duri, Bushra
School/Faculty:Colleges (2008 onwards) > College of Engineering & Physical Sciences
Department:School of Chemical Engineering
Subjects:QD Chemistry
Institution:University of Birmingham
ID Code:3867
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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