Academic literature on the topic 'Sorption-Enhanced gasification'

The energy supply in Austria is significantly based on fossil natural gas. Due to the necessary decarbonization of the heat and energy sector, a switch to a green substitute is necessary to limit CO2 emissions. Especially innovative concepts such as power-to-gas establish the connection between the storage of volatile renewable energy and its conversion into green gases. In this paper, different methanation strategies are applied on syngas from biomass gasification. The investigated syngas compositions range from traditional steam gasification, sorption-enhanced reforming to the innovative CO2 gasification. As the producer gases show different compositions regarding the H2/COx ratio, three possible methanation strategies (direct, sub-stoichiometric and over-stoichiometric methanation) are defined and assessed with technological evaluation tools for possible future large-scale set-ups consisting of a gasification, an electrolysis and a methanation unit. Due to its relative high share of hydrogen and the high technical maturity of this gasification mode, syngas from steam gasification represents the most promising gas composition for downstream methanation. Sub-stoichiometric operation of this syngas with limited H2 dosage represents an attractive methanation strategy since the hydrogen utilization is optimized. The overall efficiency of the sub-stoichiometric methanation lies at 59.9%. Determined by laboratory methanation experiments, a share of nearly 17 mol.% of CO2 needs to be separated to make injection into the natural gas grid possible. A technical feasible alternative, avoiding possible carbon formation in the methanation reactor, is the direct methanation of sorption-enhanced reforming syngas, with an overall process efficiency in large-scale applications of 55.9%.

The aim of this work is to identify the effect of the CaO phase as a CO2 sorbent and mayenite (Ca12Al14O33) as a stabilizing phase in a bi-functional material for CO2 capture in biomass syngas conditioning and cleaning at high temperature. The effect of different CaO weight contents is studied (0, 56, 85, 100 wt%) in sorbents synthesized by the wet mixing method. These high temperature solid sorbents are upgraded to bi-functional compounds by the addition of 3 or 6 wt% of nickel chosen as the metal active phase. N2 adsorption, X-ray diffraction, scanning electronic microscopy, temperature-programmed reduction analyses and CO2 sorption study were performed to characterize structural, textural, reducibility and sorption properties of bi-functional materials. Finally, sorption-enhanced reforming of toluene (chosen as tar model), of methane then of methane and toluene with bi-functional compounds were performed to study the best material to improve H2 content in a syngas, provided by steam biomass gasification. If the catalytic activity on the sorption enhanced reforming of methane exhibits a fast fall-down after 10–15 min of experimental test, the reforming of toluene reaches a constant conversion of 99.9% by using bi-functional materials.

The growing demand for sustainable energy solutions has led to significant interest in biomass gasification and methane reforming. To address this demand, a novel calcium looping process (CaLP) is proposed, which integrates biomass sorption-enhanced gasification (BSEG) with in situ calcium CaCO3-based methane reforming (CaMR). This process eliminates the need for CaCO3 calcination and facilitates the in situ utilization of CO2. The effects of gasification temperature, steam flowrate into the gasifier αG(H2O/C), reforming temperature, and steam flowrate into the reformer αR(H2O/C) were systematically evaluated. Increasing the gasification temperature from 600 °C to 700 °C enhances CO and H2 yields from 0.653 to 11.699 kmol/h and from 43.999 to 48.536 kmol/h, respectively. However, CaO carbonation weakens, reducing CaO conversion from 79.15% to 48.38% and increasing CO2 release. A higher αG(H2O/C) promotes H2 yield while suppressing CO and CH4 formation. In the CaMR process, raising the temperature from 700 °C to 900 °C improves CH₄ conversion from 64.78% to 81.29%, with a significant increase in CO and H2 production. Furthermore, introducing steam into the reformer enhances H2 production and CH4 conversion, which reaches up to 97.30% at αR(H2O/C) = 0.5. These findings provide valuable insights for optimizing integrated biomass gasification and methane reforming systems.