Validation of catalysts for a WGS process to treat a syngas stream from biomass gasification

Abstract

H2 has become crucial in the global shift toward sustainable energy, due to its decarbonizing potential. However, most production technologies remain dependent on fossil fuels, leading to significant greenhouse gas emissions. There is a growing focus on developing low-emission technologies utilizing renewable energy or including carbon capture and storage technologies (CCS). Biomass gasification integrated with water-gas shift (WGS) has been particularly notable, generating high purity H2 and facilitating CO2 capture. Industries are highly interested in developing and optimizing their operations. In Spain, Técnicas Reunidas leads efforts to upgrade and clean syngas through WGS reaction, before CO2 capture. The current work aimed to evaluate the use of catalysts, both in high-temperature shift (HTS) and low-temperature shift (LTS) individually and in series, using syngas from biomass gasification at laboratory scale. Key objectives included simulating the biomass gasification process integrated to WGS system using Aspen Plus as a baseline for experimental studies, investigating catalyst performance under near industrial conditions and validating results experimentally. Simulations proved to be a useful tool to estimate the syngas composition, also, the experimental results were consistent with theoretical, despite some discrepancies due to the ideal conditions from simulation models. In the HTS reactor within the ranges studied, higher CO inlet content led to increased CO2 production. Higher temperatures improved CO conversion, while lower GHSV extended reactant-catalyst contact time enhancing conversion. Pressure validation showed no variations in catalyst activity across the range of industrial conditions, having no impact on CO conversion. For the LTS reactor, lower temperatures enhanced CO conversion. The two-stage HTS and LTS process in series was more effective than single-stage processes, achieving higher CO conversion and improved H2 production, meeting the company's quality standards. The research provided valuable insights into the catalytic WGS process integrated with biomass gasification, offering a pathway for scaling up to pilot and industrial scales.