Recent advances and prospects in high purity H2production from sorption enhanced reforming of bio-ethanol and bio-glycerol as carbon negative processes: A review

Hydrogen has wide applications in the chemical and petroleum industries and is a clean energy carrier for electrical power generation and transportation. However, in current industries, H2is mainly obtained from the steam reforming of natural gas and coal gasification, which resulted in huge emissions of CO2(greenhouse gasses) and high energy consumption for H2purification. Hence, developing H2production technology in sustainable routes with low carbon emissions is still urgent. Sorption-enhanced steam reforming of bio-ethanol (SESRE) and sorption-enhanced steam reforming of bio-glycerol (SESRG), which coupled in-situ CO2capture with the steam reforming of bio-ethanol or bio-glycerol, are promising strategies to yield high purity of H2without emitting CO2into the atmosphere. In these strategies, high purity of H2can be produced when the high energy-consumption process such as H2purification is avoided; besides, negative CO2emissions can be achieved when the captured CO2is used or sequestered. The catalysts play a pivotal role in the steam reforming processes, and the dual-functional materials (DFMs) are well regarded as the most promising solid catalysts that contribute to high-purity H2production and CO2capture. Thus far, there is no criterion to guide DFMs engineering for H2generation in the SESRE and SESRG processes. Hence, in this work, a comprehensive review of the recent advances and prospects in SESRE and SESRG is presented, which provides constructive insight into the development of SESRE and SESRG technology. The optimum operating conditions in the SESRE and SESRG systems are analyzed via thermodynamics and kinetics, and the recent research progress of the DFMs is critically reviewed. Furthermore, the reforming reaction pathways and reaction mechanisms were discussed to improve the understanding of DFMs design. Finally, the prospect and challenges in the SESRE and SESRG strategies are outlooked.