Effect of Volatile and Ash Contents in Coal on the Volatilization of Arsenic during Isothermal Coal Combustion

Abstract

The effects of the temperature, volatile content, and ash content on the volatilization kinetics of arsenic were discussed. Six Chinese coals were tested in an isothermal thermogravimetric reactor at 600–1300 °C. Sequential chemical extraction analysis was employed to know the speciation transformation of arsenic during coal combustion. Results show that the volatilization ratio of arsenic increases with the temperature, and most arsenic volatilizes between 700 and 1000 °C. The volatile content has a positive effect on the volatilization rate of arsenic in the initial stage of combustion. With the same level of ash content, high-volatile coals (>30%) own a larger volatilization rate of arsenic (0.55–0.6% s–1) than the low-volatile coals (<12%) (0.25% s–1). In contrast, coals with a higher ash content tend to obtain a lower volatilization rate of arsenic during the process. Despite the effect of volatile and ash contents on the volatilization rate of arsenic, the final volatilization ratio of arsenic large...