Synergistic promotion of K and Ca in the efficient production of H2-rich syngas from cotton stalks

At present, hydrogen production from biomass has received more and more attention. The alkali/alkaline earth metals (AAEMs) in biomass have catalytic effect in the production of H2-rich syngas. Nevertheless, the impact of AAEMs on diverse gas constituents and the underlying mechanisms of their interactions remain elusive. In this study, steam gasification experiments were carried out on different samples before and after acid treatment in a fixed bed reactor. The results demonstrated that the abundant of AAEMs in cotton stalks could markedly enhance gas production, with H2 and syngas production reaching 29.4 mmol/gbiomass and 34.4 mmol/gbiomass, respectively. More importantly, the mechanism of K-dominant catalytic processes and the K and Ca synergistic effect in efficient production were confirmed by pickling-impregnation experiments. Furthermore, a series of commonly used characterizations further elucidated the effects of acid treatment to remove AAEMs on materials. In conclusion, the findings of this study demonstrate the effect and reaction mechanism of AAEMs in the gasification of biomass through experimentation, thereby providing insights into the synergistic effect of K and Ca.