Carbon cycle: capture and activation of carbon dioxide using hydrotalcites

Alsamaq, Suzanne (2012). Carbon cycle: capture and activation of carbon dioxide using hydrotalcites. University of Birmingham. Ph.D.

Preview

alsamaq12PhD.pdf
PDF - Accepted Version
Download (3MB)

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:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):