Low temperature adsorption of carbon dioxide in solid materials is a cost-effective option for implementing decarbonization in a retrofitting plant strategy. Among several natural and artificial sorbents, geopolymer-zeolite composites represent a valid alternative owing to the affinity and synergy between zeolite and the geopolymer binder. Thermal effects are usually associated to CO2 adsorption in solids: in particular zeolites exhibit values in the range 33 to 40 kJ/mol. The occurrence of the thermal effects (i.e. positive/negative variation of the bed temperature) impacts on the adsorption/desorption behavior and system performance. In this study, the relationship between adsorption/desorption and bed temperature has been studied in dynamic tests, complemented by thermogravimetric analysis and static sorption experiments. In dynamic tests, the maximum adsorption capacity was 1.40 mmol/g at 20% mol. of CO2 inlet concentration, whilst it resulted 0.80 mmol/g in a shorter breakthrough test. Correspondingly, the temperature peak during adsorption revealed an increase up to 20 °C. The thermal effect was exploited during desorption with a combined pressure-swing and temperature-swing strategy, leading to a shorter time for sorbent regeneration. A novel numerical model of the adsorption process well fitted the experimental results at different inlet CO2 concentration, providing insights for process design and optimization.

The relevance of thermal effects during CO2 adsorption and regeneration in a geopolymer-zeolite composite: Experimental and modelling insights

Doghieri F.;Minelli M.
2021

Abstract

Low temperature adsorption of carbon dioxide in solid materials is a cost-effective option for implementing decarbonization in a retrofitting plant strategy. Among several natural and artificial sorbents, geopolymer-zeolite composites represent a valid alternative owing to the affinity and synergy between zeolite and the geopolymer binder. Thermal effects are usually associated to CO2 adsorption in solids: in particular zeolites exhibit values in the range 33 to 40 kJ/mol. The occurrence of the thermal effects (i.e. positive/negative variation of the bed temperature) impacts on the adsorption/desorption behavior and system performance. In this study, the relationship between adsorption/desorption and bed temperature has been studied in dynamic tests, complemented by thermogravimetric analysis and static sorption experiments. In dynamic tests, the maximum adsorption capacity was 1.40 mmol/g at 20% mol. of CO2 inlet concentration, whilst it resulted 0.80 mmol/g in a shorter breakthrough test. Correspondingly, the temperature peak during adsorption revealed an increase up to 20 °C. The thermal effect was exploited during desorption with a combined pressure-swing and temperature-swing strategy, leading to a shorter time for sorbent regeneration. A novel numerical model of the adsorption process well fitted the experimental results at different inlet CO2 concentration, providing insights for process design and optimization.
Boscherini M.; Miccio F.; Papa E.; Medri V.; Landi E.; Doghieri F.; Minelli M.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11585/795960
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