The Characterization of Coal Liquefaction Products Obtained under Inert Atmosphere and Catalytic Conditions. Part I: Insoluble Products (Chars)

In this study, two types of Turkish lignite were liquefied under inert atmosphere and catalytic conditions. Catalyst was added to the reaction medium by physically mixing or impregnation. The products obtained at coal liquefaction were separated into two groups as soluble products with THF extraction and insoluble products (chars). The effects of various process parameters on the properties of chars were examined. The ash contents of chars were decreased significantly by increasing solvent to coal ratio and reaction temperature, and changed partially by pressure, catalyst type and concentration. Carbon, hydrogen and nitrogen contents of the chars decreases, but the sulphur and oxygen contents increase with increasing solvent to coal ratio, pressure, catalyst concentration, reaction time and reaction temperature. The fuel quality of chars obtained by catalyst impregnation method was determined to be much higher with respect to the catalyst physically mixing method.