Production method for low-QI (Quality Index) coal pitch

Abstract

The invention relates to a production method for low-QI (Quality Index) coal pitch. The production method is characterized by comprising the following steps: (1) circularly adding intermediate temperature pitch into a molecular distiller through a circulating pump, and (2) distilling by the molecular distiller under the conditions of vacuum negative pressure at 0.01-0.1MPa, initial distilling temperature at 130-180 DEG C and temperature difference of distilling and condensing temperature at 40-80 DEG C, continuously increasing the temperature during the distilling process, and stopping distilling when the distilling temperature is increased to 310-380 DEG C, thereby finishing the production of the low-QI coal pitch. The intermediate temperature pitch is processed according to a molecular distilling method; the production method has the characteristics of low distilling temperature, high vacuum degree, high heat-transferring efficiency, short heating time of raw materials, high separating degree, non-toxic and harmless property, pollution-free property, pure product, small energy consumption, and the like; the obtained product has the advantages that the QI value is less than 0.3%, the softening point is at 80-120 DEG C, the coking value is more than 46% and the TI value is more than 12%; the obtained product is free from sodium ion; and when the production method is adopted for soaking the pitch, the pitch soaked for two times can reach the level of the pitch soaked for three times according to a common pitch soaking method.

Description

technical field [0001] The invention belongs to the technical field of coal chemical industry, in particular to a production method of low-QI coal tar pitch. Background technique [0002] Coal tar pitch is one of the main raw materials of carbon products. Due to its special properties, coal tar pitch has always been the focus of attention of carbon experts at home and abroad. With the advancement of technology, regardless of whether coal tar pitch is used as an impregnating agent, a binder or a raw material for advanced carbon materials such as carbon fibers, the quality requirements for coal tar pitch are getting higher and higher, and the quality of coal tar pitch is most affected by QI (quinoline Insoluble matter), the lower the QI, the better the quality of coal tar pitch, so reducing the QI in coal tar pitch is the first problem to be solved to improve the quality of coal tar pitch. [0003] QI refers to quinoline insolubles, that is, 20 times the weight of quinoline i...

AI Technical Summary

Problems solved by technology

Among them, the solvent static sedimentation method has the characteristics of less investment and simple process, but the purification effect is relatively poor; the centrifugal separation method is characterized by huge equipment, high energy consumption, incomplete removal of QI, and serious pollution; the solvent extraction method has low investment and low purification effect. Good, but the yield is very low, the amount of solvent used is large, and it takes a long time; the thermal filtration method has a good separation effect, but the requirements for the filter are very high, and the filter is difficult to clean