Ultrasound-assisted classification preparation method of lignite extracts and residues

Abstract

The invention discloses an ultrasound-assisted classification preparation method of lignite extracts and residues, and belongs to the field of coal chemical industry. The preparation method particularly comprises the steps that lignite is mixed with an organic solvent, ultrasound-assisted thermal dissolution treatment is conducted under an inert gas atmosphere at 360 DEG C, a lignite and organic solvent mixture subjected to thermal dissolution treatment is centrifuged at room temperature and washed with a thermal dissolution solvent, the organic solvent in a centrifugal washing solution is separated and recycled, and room-temperature soluble lignite extracts and residues are obtained; solid residues are subjected to centrifugal washing again with an N,N-dimethylformamide solvent at room temperature, and room-temperature deposited lignite extracts and residues are obtained. According to the ultrasound-assisted classification preparation method of the lignite extracts and residues, the yield of the lignite extracts and residues is high, classification preparation for the lignite extracts and residues is achieved, in the preparation process, no specific thermal filtration separation processing equipment is needed, the dose of the thermal dissolution solvent is small, the process is simple, the cost is low, the method is suitable for industrial production, and classification extraction of the lignite extracts and residues is beneficial for subsequent processing and utilization of the lignite extracts and residues.

Description

technical field [0001] The invention belongs to the technical field of coal chemical industry, and in particular relates to the preparation of lignite hot melt. Background technique [0002] In my country's coal resources, lignite is the most abundant, accounting for about 77% of the total coal reserves, but most of the lignite is difficult to be efficiently utilized due to its high ash content, high moisture content, and low calorific value. Separation of organic compounds in coal by pyrolysis to obtain thermally soluble coal (ash-free coal) is an important clean coal utilization technology researched and developed at home and abroad in recent years. Utilizing the characteristics of low ash content of thermally soluble coal, it can be directly It is injected into a gas turbine to generate electricity by combustion, and it can also realize efficient catalytic hydrogenation liquefaction of coal (Fuel, 2015, 139, 516-522. Energy Fuels, 2009, 23, 3652-3657.) and low-temperature ...

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Problems solved by technology

At present, most of the preparation methods of coal hot solubles are to first heat-dissolve the coal (high-temperature extraction), then obtain the coal hot-melt solution through hot filtration, and finally separate the solvent to obtain the coal hot-soluble matter. The preparation process of this method requires a specific heat Filtration device, and the yield of hot soluble matter for lignite is generally low, so it is necessary to adopt a thermal solution treatment method with continuous flow of solvent to improve the yield of coal hot soluble matter (Fuel, 2001, 80, 1573-1582.), but the heat treatment process A large amount of heat-soluble solvents are required, which have certain restrictions on the practical application of the preparation of lignite heat-soluble substances, especially industrial production; in addition, this method is difficult to carry out fractional extraction of coal heat-soluble substances. In fact, after coal is heat-dissolved, There are two kinds of thermally soluble coals, soluble and deposited at room temperature, and the chemical composition and structure of these two thermally soluble coals are quite different, which are suitable for different subsequent processing and utilization (Energy Fuels, 2015, 29, 1279-1294. )

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