Method for processing low-temperature pyrolyzed coal tar

Abstract

The invention relates to a method for processing low-temperature pyrolyzed coal tar. The method comprises the following steps of: pressurizing and standing low-temperature coal tar to be pyrolyzed, dehydrating initially by changing surface tension, adding a demulsifying agent to form azeotropic water through light oil circulation and performing final dehydration; extracting crude phenate from the dehydrated low-temperature coal tar by alkaline washing; purifying the extracted crude phenate through oil-water mixed gas and decomposing through carbon dioxide so as to obtain crude phenol; and dehydrating the obtained crude phenol, deslagging and rectifying so as to obtain a target product. By the method, the phenol extraction rate of the low-temperature pyrolyzed coal tar is over 95 percent, the problem of difficult oil and water separation can be solved and the dehydration rate after processing is between 0.5 and 1 percent. The method is a processing method which has low cost and reasonably utilizes a low-temperature coal tar resource.

Description

technical field [0001] The invention relates to a low-temperature pyrolysis coal tar processing method, in particular to a low-temperature pyrolysis coal tar processing method in which phenol is first extracted and then distilled. Background technique [0002] According to the different pyrolysis temperature, coal tar can be divided into low-temperature coal tar and high-temperature coal tar. With the massive development of low-rank coal with abundant reserves in my country, the reasonable separation and processing of low-temperature coal tar has become an important issue in the field of pyrolysis coal tar. [0003] Due to the low pyrolysis temperature and a small amount of secondary pyrolysis, the composition characteristics and processing methods of low-temperature coal tar are obviously different from those of high-temperature coal tar. The content of phenolic compounds and saturated hydrocarbons is also higher than that of high-temperature coal tar, while the content of a...

AI Technical Summary

Problems solved by technology

[0004] The early methods of low-temperature pyrolysis of coal tar mainly used processing methods such as centrifugal separation, atmospheric and vacuum distillation, solvent dilution precipitation and distillation coking. Because low-temperature coal tar contains a large amount of phenol (an important chemical raw material, Account for about 35% of total weight,), and existing these methods all can not extract phenol, cause the low-temperature coal tar that contains many precious compounds (as phenolic compound etc.) at present only as a kind of low price, even cheap Liquid fuels are sold in the market, which is a great waste of comprehensive utilization of resources

Images