A recovery method of extractant in high-viscosity coal-based oil residue raffinate

Abstract

The method relates to a method for recycling extractant in high-viscosity coal-based oil dreg extraction residues. The method comprises the following steps: (1) carrying out solid-liquid separation ofan extraction residue phase and residues to respectively obtain an extraction phase and a viscous solid phase and introducing the extraction phase into a next process; (2) adding the viscous solid phase into a film dryer and indirectly heating to respectively obtain washing oil steam and oil dreg particles; (3) cooling and separating the oil dreg particles to respectively obtain cooled oil dreg particles and a gas phase, introducing the gas phase into a torch system and introducing the cooled oil dreg particles into a residue discharging pipeline; (4) enabling the washing oil steam to flow through a Venturi washing tower to respectively obtain tower bottom circulating liquid, condensed washing oil and uncondensed light oil steam, cooling the tower bottom circulating liquid and then returning the tower bottom circulating liquid to a Venturi in the tower, returning the condensed washing oil to an extraction stage for reusing; (5) condensing the uncondensed light oil steam to respectively obtain uncondensed gas and condensed excess oil in a tower tray at the top of the tower; and (6) exhausting the uncondensed gas. The method is low in investment, easy to implement and high in benefit.

Description

technical field [0001] The invention relates to the technical field of coal chemical industry, in particular to a method for recovering an extractant in a high-viscosity coal-based oil residue raffinate. Background technique [0002] Coal liquefaction technology is one of the important processes in coal chemical industry, and it is an effective technical way to solve my country's energy demand. Coal liquefaction residue is usually the residue obtained after vacuum distillation of coal hydrogenation liquefaction products. The coal liquefaction process will produce liquefaction residues that account for 20% to 30% of the total coal input. The oil residue includes heavy liquefied oil, asphalt Such substances and unconverted coal, etc., among which, the content of heavy oil and bituminous substances accounts for about 50% of the oil residue. [0003] With the rapid development of the industrialization of direct coal liquefaction, how to efficiently utilize heavy oil and bitumin...

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Problems solved by technology

[0003] With the rapid development of the industrialization of direct coal liquefaction, how to efficiently utilize heavy oil and bituminous substances in the liquefaction residue has gradually become the focus of research. The traditional methods include blending, dry distillation and gasification. These methods cannot To give full play to the unique advantages of high added value of heavy oil and bituminous substances in the residue, the method currently used is to use organic solvent extraction to recover this part of the oil

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