CaO-based chemical looping gasification of biomass for the production of hydrogen-enriched gas and CO₂ negative emissions: A review

Hydrogen as an energy carrier plays an important role in the energy consumption system. Compared to other technologies, CaO-based chemical looping gasifi cation of biomass (CaO-based CLGB) is a sustainable way for producing hydrogen-enriched gas and CO₂ negative emissions. As the residence time of fi xed carbon in a gasifi er is short, the CO₂ capture effi ciency of the CaO-based CLGB system is low. To conquer this problem, the CaO-based CLGB con fi guring with carbon stripper was discussed in this paper. The decay of the CO₂ capture capacity of natural CaO-based sorbents is a main factor to restrain the development of CaO-based CLGB. Some promising methods have been applied to solve this problem. According to the purpose of technology, three representative technologies were discussed in this paper. Compared to other technologies, replacing natural or synthetic CaO-based sorbents is an economic and environmentally friendly solution. Calcium-rich industrial waste (CRIW) combined with the characteristics of cheapness, wide-source and environmental protection is an ideal substitute of CaO-based sorbents for replacing natural or synthetic CaO-based sorbents. The prospect of CRIW as a CaO-based sorbent was discussed in this paper.