Effect of Various Experimental Parameters on the Swelling and Supercritical Extraction Properties of Lignite

Abstract The original lignite sample, the samples swollen in dimethylsulfoxide (DMSO), dimethylformamide (DMF), pyridine, tetrahydrofuran (THF), acetone, ethylenediamine (EDA), N-methyl-2-pyrrolidone (NMP), tetrabutylammonium hydroxide (TBAH), the samples impregnated by ZnCl2 as catalyst and the samples both swollen in the solvents and impregnated by ZnCl2 were subjected to the supercritical toluene extraction and the effects of temperature, pressure, pre-swelling procedure, hydrogen donor solvent (tetralin), and catalyst on the extract yields were investigated.