Hydrogen with high purity can be directly derived from fossil and renewable energy sources, like natural gas, coal and biomass, by the so-called sorption-enhanced reforming (SER) and water gas shift (SEWGS) processes characterized by simultaneous CO2 capture.This paper deals with CO2 capture on a solid sorbent under cyclic (carbonation/decarbonation), industrially relevant conditions. Hydrotalcite-like compounds (double Mg/Al hydroxy-carbonates), in comparison to CaO-based sorbents, are characterized by a comparatively smaller energy demand for regeneration and the operating temperature range is much lower (200-400°C), making them particularly attractive for SEWGS processes.Different kinds of hydrotalcite were prepared and the Mg2+/Al3+ ratio, the effect of a promoter addition and the substitution of the bivalent cation (Ca instead of Mg) were investigated, with commercial and laboratory synthesized samples.Original and heat-treated hydrotalcite samples were characterized by XRD, BET and SEM-EDX in order to detect composition, crystalline phases and morphology. Sorption capacity was investigated under cyclic conditions by means of TGA-DSC. Step-response experiments were performed in a micro-reactor to evaluate the kinetic behavior, and a first-order-with-dead-time model for gas mixing was used to fit the results and work out the CO2 dynamic load on the solid phase. © 2013 The Institution of Chemical Engineers.

Experimental evaluation of Mg- and Ca-based synthetic sorbents for CO2 capture

Stendardo, S.
2014

Abstract

Hydrogen with high purity can be directly derived from fossil and renewable energy sources, like natural gas, coal and biomass, by the so-called sorption-enhanced reforming (SER) and water gas shift (SEWGS) processes characterized by simultaneous CO2 capture.This paper deals with CO2 capture on a solid sorbent under cyclic (carbonation/decarbonation), industrially relevant conditions. Hydrotalcite-like compounds (double Mg/Al hydroxy-carbonates), in comparison to CaO-based sorbents, are characterized by a comparatively smaller energy demand for regeneration and the operating temperature range is much lower (200-400°C), making them particularly attractive for SEWGS processes.Different kinds of hydrotalcite were prepared and the Mg2+/Al3+ ratio, the effect of a promoter addition and the substitution of the bivalent cation (Ca instead of Mg) were investigated, with commercial and laboratory synthesized samples.Original and heat-treated hydrotalcite samples were characterized by XRD, BET and SEM-EDX in order to detect composition, crystalline phases and morphology. Sorption capacity was investigated under cyclic conditions by means of TGA-DSC. Step-response experiments were performed in a micro-reactor to evaluate the kinetic behavior, and a first-order-with-dead-time model for gas mixing was used to fit the results and work out the CO2 dynamic load on the solid phase. © 2013 The Institution of Chemical Engineers.
Solid sorbents;SEWGS);Sorption enhanced reforming and water gas shift (SER
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.12079/2503
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