Steam gasification of cellulose pulp char: Insights on experimental and kinetic study with a focus on the role of Silicon

This paper deals with steam gasification kinetics of cellulose pulp extracted from biomass with on the focus silicon effect. Isothermal TGA tests were performed under various operating conditions. The gasification reactivity increased with increasing temperature and steam pressures. The reactivity of cellulose pulp biochar was 3 times lower than that of the biomass char. This is attributed to the difference in the inorganic content, namely AAEM and Si. The gasification of pulp biochar revealed the negative effect of Si, which was the main inorganic element present in the cellulose pulp. Biochar reactivity decreased with increasing Si concentration. The reactivity could be correlated to Si content. The morphological structure had an impact at a low conversion rate, although it was less influential than Si. Thus, a kinetic model for describing the gasification kinetics was developed using %Si as a key-parameter. The comparison to the experimental data showed that the proposed model can reasonably predict the gasification behavior of different biochars with satisfactory accuracy (<10%) as far as industrial processes are concerned. Further analysis of alkaline-washed cellulose confirmed the inhibiting effect of Si on the gasification process. The reaction time was 2.5 times lower after the partial elimination of Si.