Treatment Variable Effects on Supercritical Gasification of High-Diversity Grassland Perennials

Low-input high-diversity (LIHD) mixtures of native grassland perennials were subjected to a supercritical treatment process with the aim of obtaining hydrogen-rich gases. The process was studied based on the following treatment variables: reaction temperature (374 °C to 575 °C, corresponding to a pressure range of 22.1 to 40 MPa), residence time (10 to 30 min), biomass content in the feed, and catalysts (0% to 4% NaOH and solid alkali CaO–ZrO₂). The gaseous phase produced from gasification of LIHD primarily consisted of hydrogen (H₂), with a mixture of carbon monoxide (CO), methane (CH₄), and carbon dioxide (CO₂). The statistical significance of treatment variables was evaluated using analysis of variance (ANOVA). It showed that at the level of P?<?0.05, temperature, catalysts, and biomass content in the feed significantly affected gas yields, while residence time was not significant.