Method for depolymerizing lignite by using ionic liquid

Abstract

The invention provides a method for depolymerizing lignite by using an ionic liquid, belonging to the technical field of comprehensive utilization of lignite. The method comprises the following steps: selecting an ionic liquid which is beneficial to efficiently depolymerizing lignite, adding lignite powder and the ionic liquid into a reaction kettle, heating under the assisting action of microwaves to 50-350 DEG C, and reacting for 2 minutes to 5 hours to obtain a reaction product; after the reaction finishes, separating the reaction product from residues by a high-speed centrifugal separation method or an organic solvent washing and filter membrane filtration method; and washing the supernatant or filtrate with water, evaporating to obtain the organic solvent, reaction product and ionic liquid, wherein the organic solvent and ionic liquid can be recycled, and the lignite reaction product can be separated by the organic solvent to obtain high-added-value organic chemicals of alkyl aromatics and multielement cyclic aromatics containing alkoxy groups and phenolic groups. The method has the advantages of simple technique, clean process, and high added value of the product, and needs no or little harmful or volatile organic solvents.

Description

Technical field:

[0001] The invention belongs to the technical field of comprehensive utilization of lignite, and in particular relates to a method for depolymerizing lignite in an ionic liquid under mild conditions and separating a depolymerization product from the ionic liquid. Background technique:

[0002] my country is rich in medium and low-rank coal resources, especially the proven reserve of lignite reaches 130.3 billion tons. Due to the presence of high ash (about 30%), high moisture (20-50%) and low calorific value (about 14MJ.kg) of most lignite -1 ), low ash melting point, poor thermal stability, and easy weathering and spontaneous combustion are considered inferior fuels. However, lignite is a coal with a low degree of metamorphism, and it retains the macromolecular structure of coal-forming plants to a greater extent. By choosing an appropriate method to depolymerize lignite, ultra-clean coal and many high value-added oxygen-containing organic chemicals can b...