Catalytic gasification of biomass (Miscanthus) enhanced by CO2 sorption

Abstract

The main objective of this work concerns the coupling of biomass gasification reaction and CO sorption. The study shows the feasibility to promote biomass steam gasification in a dense fluidized bed reactor with CO sorption to enhance tar removal and hydrogen production. It also proves the efficiency of CaO-CaAlO/olivine bi-functional materials to reduce heavy tar production. Experiments have been carried out in a fluidized bed gasifier using steam as the fluidizing medium to improve hydrogen production. Bed materials consisting of CaO-based oxide for CO sorption (CaO-CaAlO) deposited on olivine for tar reduction were synthesized, their structural and textural properties were characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), and temperature-programmed reduction (TPR) methods, and the determination of their sorption capacity and stability analyzed by thermogravimetric analysis (TGA). It appears that this CaO-CaAlO/olivine sorbent/catalyst presents a good CO sorption stability (for seven cycles of carbonation/decarbonation). Compared to olivine and Fe/olivine in a fixed bed reactor for steam reforming of toluene chosen as tar model compound, it shows a better hydrogen production rate and a lower CO selectivity due to its sorption on the CaO phase. In the biomass steam gasification, the use of CaO-CaAlO/olivine as bed material at 700 °C leads to a higher H production than olivine at 800 °C thanks to CO sorption. Similar tar concentration and lighter tar production (analyzed by HPLC/UV) are observed. At 700 °C, sorbent addition allows to halve tar content and to eliminate the heaviest tars.

Integrated catalytic adsorption steam gasification in a bubbling fluidized bed for enhanced H2 production: perspective of design and pilot plant experiences

“…at temperatures higher than 727 and 675°C, respectively. Moreover, Zamboni et al . and Aarlien et al .…”

“…This increase clearly shows the existence of reverse carbonation (calcination reaction) in the system, which has been reported by Xu et al 15 and Pfeifer et al 16 at temperatures higher than 727 and 675 °C, respectively. Moreover, Zamboni et al 17 and Aarlien et al 18 reported maximum CO 2 sorption temperatures at 660 and 700 °C for enhanced H 2 production, respectively. This suggests that the optimum temperature of 675 °C is suitable for high H 2 composition with minimal CO 2 in ICA steam gasification, and also provides evidence of a good fluidized bed operation in the present study.…”

“…Steam methane reforming and char gasification are both endothermic reactions and the activities depend heavily on high temperature. However, temperatures greater than 725°C for biomass gasification with in situ CO 2 adsorbent in the bed give rise to concern due to reverse carbonation, especially when CaO is used as an adsorbent . Using a steam methane reforming catalyst in the bed not only enhances hydrogen production but also provides more CO (even at low temperature) to allow the water shift reaction to move in a forward direction.…”

Enrichment of Hydrogen Production from Biomass‐Gasification‐Derived Syngas over Spinel‐Type Aluminate‐Supported Nickel Catalysts

“…[1,2] Through ag asificationp rocesst hat involves as eries of thermochemical conversion reactions,b iomass solids can be converted to gas-phasep roducts.T he gas/vapor-phase end productso fb iomass gasification are composed mainlyo fC O, CO 2 ,C H 4 ,H 2 ,a nd low concentrations of C 2 -C 3 species. [3,4] Thec oncentration of H 2 in syngas produced from the gasification of biomass is usuallyl ow,b ut can be increased by the followingr eactions that produce additional H 2 :…”

Technoeconomic perspectives on sustainable CO2 capture and utilization

“…They show that adding 10 mol% Li 2 CO 3 promotes both sorption and desorption due to a K-Li eutectic phase that promotes the diffusion of K and CO 2 into the sorbent matrix. Second, Zamboni et al (Zamboni et al 2016) demonstrate the synergistic effect of high-temperature sorption on steam-based biomass gasification in a fluidized bed of CaOCa 12 Al 14 O 33 /Olivine to enhance hydrogen production and tar removal.…”