Technique Study on Removing Oxygen Containing Compounds in Lignite by Solvent Extraction

In order to remove oxygen containing compounds in lignite and improve the comprehensive utilization of lignite value, alkali extraction coupled supercriti cal methanol treatment had been used for advanced treatment of lignite. The extraction temperature, alkali concentration and ratio of solvent to lignite on the removal ef fect of the oxygen containing compounds had been researched. Experimental results showed that the optimal conditions for alkali extraction were extraction temperatur e 180。C, alkali concentration 1%, solvent ratio 6 : 1. Under this condition, the oxygen removal rate was 32% in lignite. Coupling alkali extraction and supercritical metha nol treatment, the total deoxidizing rate had been increased to more than 40% and carboxyI and phenolic hydroxyl groups had been removed efficiently.