The main goal of this work is to access the benefits of using a sorption-enhanced membrane reactor (SEMR) comparatively to a sorption-enhanced reactor (SER) and a traditional reactor (TR) for H2 production through glycerol steam reforming (GSR). A SER, where a potassium-promoted hydrotalcite-like material (K-MG30) was used to capture the CO2 produced during GSR on an alumina supported Rh catalyst, was tested. An enhancement of the H2 production was observed not only during the pre- and breakthrough of CO2 but also during the post-breakthrough as compared to the conventional TR. While the initial enhancement was mostly due to CO2 sorption and affected more directly the water-gas shift (WGS) reaction, the observed catalytic activity of K-MG30 towards glycerol decomposition and mainly WGS reaction was responsible for the improved performance during post-breakthrough. Still, considerably higher H2 purity was obtained in the first moments. Ultimately, a much significant improvement in terms of H2 production was observed in the SEMR, where a Pd-Ag membrane separated selectively the hydrogen from the other gases. An increment of the maximum H2 yield in the pre- and breakthrough regions from 1.6 up to 3.6 mol∙molfedglycerol-1 was obtained. The simultaneous removal of both H2 and CO2 significantly benefited the WGS reaction. Consequently, only H2 was obtained in the gas phase of the retentate stream during the pre-breakthrough period. Moreover, ultra-pure H2 was obtained in the permeate side of the dense Pd-Ag membrane, meaning that if the SEMR is continuously operated in the pre-breakthrough region, pure H2 would continuously be obtained in both retentate and permeate streams.

From sorption-enhanced reactor to sorption-enhanced membrane reactor: A step towards H2 production optimization through glycerol steam reforming

Tosti S.;
2019

Abstract

The main goal of this work is to access the benefits of using a sorption-enhanced membrane reactor (SEMR) comparatively to a sorption-enhanced reactor (SER) and a traditional reactor (TR) for H2 production through glycerol steam reforming (GSR). A SER, where a potassium-promoted hydrotalcite-like material (K-MG30) was used to capture the CO2 produced during GSR on an alumina supported Rh catalyst, was tested. An enhancement of the H2 production was observed not only during the pre- and breakthrough of CO2 but also during the post-breakthrough as compared to the conventional TR. While the initial enhancement was mostly due to CO2 sorption and affected more directly the water-gas shift (WGS) reaction, the observed catalytic activity of K-MG30 towards glycerol decomposition and mainly WGS reaction was responsible for the improved performance during post-breakthrough. Still, considerably higher H2 purity was obtained in the first moments. Ultimately, a much significant improvement in terms of H2 production was observed in the SEMR, where a Pd-Ag membrane separated selectively the hydrogen from the other gases. An increment of the maximum H2 yield in the pre- and breakthrough regions from 1.6 up to 3.6 mol∙molfedglycerol-1 was obtained. The simultaneous removal of both H2 and CO2 significantly benefited the WGS reaction. Consequently, only H2 was obtained in the gas phase of the retentate stream during the pre-breakthrough period. Moreover, ultra-pure H2 was obtained in the permeate side of the dense Pd-Ag membrane, meaning that if the SEMR is continuously operated in the pre-breakthrough region, pure H2 would continuously be obtained in both retentate and permeate streams.
Glycerol; Hydrogen; Sorption-enhanced membrane reactor; Sorption-enhanced reactor; Steam reforming
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.12079/52197
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