Influence of devolatilization treatment on gasification kinetics characteristics of biomass across different gasification stages

Gasification experiments on devolatilization (MTD) char derived from corn stalk in a steam atmosphere were conducted using a thermogravimetric analyzer. The gasification reactivity of MTD-char at different gasification stages was investigated, and the internal correlation between the gasification kinetics characteristics and physicochemical properties of MTD-char was explored. The results demonstrated that the reduction of H/C and O/C after the MTD of corn stalk increased the final gasification temperature, maximum gasification weight loss rate, and corresponding temperature, whereas the increase in alkali and alkaline earth metal elements, especially K, reduced the gasification initiation temperature and activation energy, thereby improving gasification reactivity. Furthermore, because of the formation of graphite intercalation compounds, the catalytic effect of K on biomass gasification reactivity was mainly concentrated in the middle and late stages of gasification, the average gasification reaction rates in the middle and late stages of gasification increased from 0.338 %/°C and 0.22 %/°C in corn stalk to 0.644 %/°C and 0.597 %/°C in the MTD-char obtained at 550 °C, respectively. This study is of great significance in revealing the gasification reaction mechanism of MTD-char and in the design of relevant gasification reactors.