Experimental and computational evaluation of activated carbons for carbon dioxide capture from high pressure gas mixtures

Caldwell, Simon James (2015). Experimental and computational evaluation of activated carbons for carbon dioxide capture from high pressure gas mixtures. University of Birmingham. Ph.D.

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Abstract

This PhD project aimed to study the separation of carbon dioxide from high pressure gas mixtures as it is directly applicable to pre-combustion carbon dioxide capture. Adsorption isotherms were produced and best fit by the Langmuir-Freundlich and dual-site Langmuir (DSL) isotherms. Breakthrough experiments investigated the separation under dynamic conditions. These showed that adsorption capacities need to be studied on a volumetric basis. The multicomponent DSL isotherm model was the most suitable for predicting breakthrough capacities.

An axial dispersed plug flow model was validated against the experimental data with a reasonable accuracy. Cyclic experiments were validated, which were found to be restricted by the surrounding pipework and instruments. A parameter sensitivity analysis indicated the particle diameter, bed voidage and particle voidage had the greatest effect on the breakthrough curve.

Pressure swing adsorption systems were also simulated. Simple cycles and counter-current operation were proven to not produce high quality heavy or light product. A novel purge recycle step was introduced and improved the carbon dioxide purity. A carbon dioxide purity of 93.8% was achieved by using a rinse step after pressure equalisation steps, but required a compressor and resulted in a significant reduction in carbon dioxide capture rate.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):