High-purity H2 production through glycerol steam reforming in multifunctional reactors

Abstract

Different hybrid intensified reactor configurations (sorption-enhanced reactor-SER-, membrane reactor-MR- and sorption-enhanced membrane reactor-SEMR-) were studied aiming to assess their benefits comparatively to a traditional reactor (TR) for high-purity H2 production through glycerol steam reforming (GSR). In the different reactor configurations, home-prepared materials have been employed: a NiAlLaOx reforming catalyst, an hydrotalcite-based sorbent for CO2 capture, and a composite-membrane with a Pd-thickness of ca. 9 mu m to selectively separate H2 from the reaction medium. An enhancement of 5.5 % in the H2 production was observed in the SER during the pre-breakthrough stage in comparison to the conventional TR. Further enhancement of the H2 yield was observed using the SEMR during pre-breakthrough, being attained an H2 yield of 6.6 molH2 & sdot; mol- 1G , in at 475 degrees C and retentate pressure of 4.0 bar (1.0 bar in the permeate side), which represents an average enhancement of 80 % in comparison to the TR configuration, evidencing also the positive effect of the membrane upon being coupled with the CO2-selective sorbent. The simultaneous removal of both H2 and CO2 clearly improves the overall GSR performance, allowing to obtain highly-pure H2 in both retentate and permeate sides during pre-breakthrough. It was also demonstrated that the use of a real crude glycerol effluent in the SEMR allows to obtain highly-pure renewable H2 through steam reforming in both reactor sides, thus evidencing a possible viable path for biomass-based H2 production, while also allowing to promote the economics of the biodiesel manufacturing process.