Equilibria and kinetics of CO2 adsorption on hydrotalcite adsorbent

Experimental data for the adsorption and desorption of CO2 on potassium promoted hydrotalcite adsorbent were measured under conditions depicting the separation enhanced steam-methane reforming process. Adsorption saturation capacities of 0.58 and 0.65 mol/kg were measured at 753 and 673 K, respectively, under wet feed conditions. An ~ 10% reduction of the saturation capacity was observed under dry feed conditions. In both cases, a Langmuir model adequately described the adsorption isotherm. Experimental data revealed the rapid degradation of the adsorbent under dry feed conditions, and higher losses at higher temperatures. Adsorbent regeneration was possible by means of a steam purge, but some irreversible loss in capacity was indicated for very long times-on-stream. A dynamic model accounting for semi-technical scale operation was developed to describe the key operating steps of the pressure swing based adsorptive process. Kinetic studies suggested mass transfer control for the adsorption, depressurization, and purge steps of operation. The study illustrated the complexities of CO2 adsorption on hydrotalcite. Some variation in adsorption parameters is expected depending on the conditions of pre-treatment. For adsorbent previously not contacted with steam or CO2 feed, observations indicated an initial strong adsorption of material, depicting a chemisorption mechanism.

Equilibria and kinetics of CO 2 adsorption on hydrotalcite adsorbent

Adsorption-enhanced steam-methane reforming

Combustion and gasification of coals in fixed-beds

https://hal.archives-ouvertes.fr/hal-02594054/document

Chi-Hsiung Li

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