Purification method for coal pitch

Abstract

The invention relates to a method for purifying coal tar pitch, which is characterized in that the method comprises the following steps: using mid-temperature coal tar pitch or coal tar maltha as a raw material, and using a mixed solvent consisting of arene from coking and coal oil or light diesel fuel from petrifaction to perform sufficient mixing and dissolving at certain temperature; performing centrifugal separation to remove the residue, and distilling the obtained clear solution to remove and reclaim the solvent so as to obtain the purified pitch with the content of quinoline undissolved substances of between 0.01 and 0.04 percent. The method has the advantages of simple process, low production cost, high separation efficiency and lower QI content; besides, the purified pitch can completely meet the requirements on producing the products of needle coke, carbon fiber and the like.

Description

technical field [0001] The invention relates to a method for purifying coal tar pitch, which belongs to the field of deep processing of coal tar pitch. Background technique [0002] my country's coal tar pitch is very rich in resources, but currently it is mainly used as primary products such as medium temperature coal tar pitch, modified pitch, fuel oil, etc., with low added value and serious waste of resources. In fact, medium-temperature coal tar pitch or coal tar soft pitch has a high content of aromatics, and is an important raw material for high value-added products such as needle coke and carbon fiber. The problem is that to prepare this type of high value-added products, quinoline insolubles (QI) must first be completely removed. At present, the removal process of quinoline insolubles in coal tar pitch is very immature. For example, the patent document CN101289625 discloses a method of using medium-temperature coal pitch or coal tar soft pitch as a raw material, us...

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Problems solved by technology

[0003] Patent document CN101294090 discloses a centrifugal purification method for coal tar pitch, but it is operated at room temperature, the temperature is too low, the solvent has a very low dissolving ability for pitch, a large amount of solvent must be used, the processing load is high, the equipment is huge, and the energy consumption of solvent recovery is very high ;Using a single-component solvent, there is no flocculation effect on QI particles, and the centrifugation effect is limited. It must be further processed with a 0.02-0.8 μm filter material, and the process is very complicated.