The gasification reactivity of residual coal chars from supercritical fluid extraction of coal

The gasification rate of chars from the supercritical fluid extraction of coals was measured in a carbon dioxide atmosphere using an isothermal thermogravimetric analyzer. The chars were prepared by pyrolysing residual coals extracted with toluene or toluene-tetralin mixtures as supercritical solvents. The gasification rate of chars was enhanced by extraction, with the supercritical fluids. The effects of extraction conditions and coal rank on the gasification rate of residual char were evaluated. The results suggested that the increase in the gasification rate can be attributed to an increase in the surface area of residual coal resulting from the extraction.