The effect of swelling pretreatment on the coal liquefaction in tetralin with microwave energy

Three Turkish coals, a Zonguldak coal and Tuncbilek and Beypazari lignites were used to examine the effect of solvent swelling pretreatment on the solubilization and dissolution behavior. Methanol, THF ( tetrahydrofuran) and TBAH ( tetrabutylammonium hydroxide) were used as swelling agents. For the investigation of dissolution behavior of coals, the microwave heating period was changed from 10 to 30 min at 5 min intervals. While solvent pretreatment enhanced the THF solubles yields for the Zonguldak coal, solvent treatment decreased the THF solubles yields for the Tuncbilek and Beypazari lignites. The data obtained in this study indicated that the formation mechanism of AS ( asphaltenes), PAS ( preasphaltenes) and oils depend on the coal and swelling agent type.