High-purity H2 production through glycerol steam reforming in multifunctional reactors
M. Salomé Macedo, Elka Kraleva, Heike Ehrich, Natalia Uriarte, R. Sanz, D. Alique, M.A. Soria, Luı́s M. Madeira
Abstract
• Multifunctional reactors have been studied to improve glycerol steam reforming (GSR); • Sorption-enhanced reactor (SER), membrane reactor (MR) and sorption-enhanced membrane reactor (SEMR) seem promising; • An improvement of 80 % in the H 2 yield was observed when using a SEMR; • Real crude glycerol effluent allows to obtain highly-pure renewable H 2 in both SEMR sides. 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 H 2 production through glycerol steam reforming (GSR). In the different reactor configurations, home-prepared materials have been employed: a NiAlLaO x reforming catalyst, an hydrotalcite-based sorbent for CO 2 capture, and a composite-membrane with a Pd-thickness of ca. 9 μ m to selectively separate H 2 from the reaction medium. An enhancement of 5.5 % in the H 2 production was observed in the SER during the pre-breakthrough stage in comparison to the conventional TR. Further enhancement of the H 2 yield was observed using the SEMR during pre-breakthrough, being attained an H 2 yield of 6.6 mol H 2 ∙ mol G,in -1 at 475 °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 TR configuration, evidencing also the positive effect of the membrane upon being coupled with the CO 2 -selective sorbent. The simultaneous removal of both H 2 and CO 2 clearly improves the overall GSR performance, allowing to obtain highly-pure H 2 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 H 2 through steam reforming in both reactor sides, thus evidencing a possible viable path for biomass-based H 2 production, while also allowing to promote the economics of the biodiesel manufacturing process.