Method for extracting heavy liquefied oil from residue of coal direct liquefaction, extracted heavy liquefied oil, and application thereof

Abstract

The invention provides a method for extracting heavy liquefied oil from the residue of coal direct liquefaction, extracted heavy liquefied oil, and an application thereof. The method comprises steps that: (a) coal liquefaction residue powder and an extraction solvent are mixed in a residue extraction apparatus, and the residue is extracted, such that heavy liquefied oil in the residue is extracted into the solvent; (b) solid-liquid separation is carried out upon the extraction mixture and the extraction residue obtained in the step (a) by using a cyclone separator, such that a supernatant mixture and an underflow mixture are obtained; (c) fine filtration is carried out upon the supernatant mixture obtained in the steps (b), and the filtrate is delivered in to a distillation separation apparatus; (d) pressure-rough-filtration is carried out upon the underflow mixture obtained in the step (b), the obtained filtrate is processed through fine filtration, and the obtained filtrate is delivered into the distillation separation apparatus; (e) the filtration mixture is separated in the distillation separation apparatus; the solvent is recovered and reused; and heavy liquefied oil with a solid impurity content lower than 0.1wt% is obtained. Between the step (d) and the step (e), a step (f) can be included. The steps (f) is that: the filtration residue obtained in the rough-filtration process in the step (d) is dried through meat medium back flushing; and the residual solvent is recovered and delivered into the distillation separation apparatus.

Description

technical field [0001] The invention relates to the field of coal deep processing, in particular to a method for solid-liquid separation and solvent recovery after coal liquefaction residue extraction. Specifically, the present invention provides a method for extracting heavy liquefied oil from coal direct liquefaction residue, the heavy liquefied oil extracted by the method and its application. Background technique [0002] Direct coal liquefaction is an important supplement to the shortage of oil resources in my country, and is of great significance to my country's energy security. [0003] In all current direct coal liquefaction processes, the conversion rate of coal cannot reach 100%, and there is always liquefaction residue accounting for about 30% of the liquefied coal input in the end. Liquefaction residue is a high-carbon, high-ash and high-sulfur substance mainly composed of coal minerals, catalysts, unreacted coal, asphaltene and heavy liquefied oil. Among them, ...

AI Technical Summary

Problems solved by technology

Although this process can obtain an extraction product with an ash content of less than 1%, and the solvent recovery rate is relatively high, the extraction temperature is relatively high at 325-340°C and the pressure is relatively high at about 5.0MPa

In addition, the extraction conditions of this process are relatively harsh, the energy consumption of the device is high, the equipment requirements are high, and the efficiency of sedimentation separation is not high

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