The effect of preswelling and/or pretreatment of some Turkish coals on the supercritical fluid extract yield

The effects of preswelling, and/or pretreatment with 1N HCl of four Turkish coals (Bolu-Göynük, Seyitömer, Tunçbilek and Soma-Merkez) on the supercritical toluene extract yields have been investigated. Methanol, 1,4-dioxane, THF (tetrahydrofuran), pyridine and EDA (ethylenediamine) were used as swelling agents. Solvent swelling and pretreatment with 1N HCl of coals significantly enhanced the liquid yields. The effectiveness of the swelling solvents in enhancing the liquid yield is in the same order as their swelling ratios. Swelling in EDA and pyridine were more effective for the extraction of coals. The highest improved liquid yields in supercritical toluene for each coal was obtained by the combined effects of pretreatment and preswelling of coals. No simple trend in reactivity increment with properties of coals was observed.