A kind of method for reducing polycyclic aromatic hydrocarbon content in coal tar pitch

Abstract

A method for reducing the content of polycyclic aromatic hydrocarbons in coal tar pitch, said method is to add potassium permanganate modifier into distilled water, and mix uniformly to obtain potassium permanganate solution; Freeze, then pulverize and sieve to obtain coal tar pitch powder with a particle size of less than 80 meshes, add the coal tar pitch powder to the potassium permanganate solution prepared above at room temperature, keep the stirring speed constant, and react at room temperature to prepare Modified coal tar pitch was obtained. The invention is carried out at normal temperature, and the content of strong carcinogen polycyclic aromatic hydrocarbons in the obtained modified coal tar pitch is greatly reduced, and the process is simple in operation, saves energy and reduces consumption, does not produce secondary pollution, and is easy for industrialized production.

Description

technical field [0001] The invention relates to a method for modifying coal tar pitch, in particular to an environment-friendly method for modifying coal tar pitch using potassium permanganate as a modifying agent. technical background [0002] Coal tar pitch is a bulk product obtained after deep processing of coal tar. my country is a major producer of coal tar pitch. In the last century, coal tar pitch was widely used in road paving. The content of polycyclic aromatic hydrocarbons in coal tar pitch is relatively high, among which strong carcinogens such as benzopyrene A large amount exists in coal tar pitch. With the enhancement of people's awareness of environmental protection, the application of coal tar pitch is largely restricted due to its potential toxicity. However, with the increasing shortage of oil resources in recent years, it can be used for road paving. Therefore, it is particularly important to carry out low-toxicity modification of coal tar pitch so that it ca...

AI Technical Summary

Problems solved by technology

[0005] For example, "Reducing Benzo (a) pyrene Content of Coal-tar-pitch Modified by Styrene-butadiene Rubber Through Dynamic Vulcanization" in 2012, page 292-300 of volume 743-744, the reaction uses SBR as a modifier and sulfur as a crosslinking agent , reacted at 180°C with a stirring speed of 4000rpm for 30 minutes, and the content of benzopyrene was reduced by nearly half, but the process was complicated and the high temperature energy consumption was large

[0006] 2014 "Research on Coal Tar Pitch Toxicity Reduction and Its Performance" Issue 01-03 and 08, the document reported that 3% PS, 7% PEG, 5% paraformaldehyde and 0.5% polyphosphoric acid and other mixtures to process coal tar pitch, the content of poisons contained in the obtained modifier is greatly reduced, and the effect is obvious, but it is obvious that this method involves many modifiers and the cost is high

The benzopyrene content of the obtained modified coal tar pitch is reduced by 36%-72%, but its technological process is relatively cumbersome and difficult for large-scale industrial application

[0008] The publication number is CN103450693A, and the name is "composite modified coal tar pitch and its preparation method". The main raw materials are coal tar pitch and residual oil, and the polymer materials with modifiers of 0-20wt% are waste rubber, most polymers , benzaldehyde, paraformaldehyde, trioxane polyethylene glycol, etc., and 0-5wt% additives such as polyphosphoric acid, elemental sulfur, etc., after treatment, the content of benzopyrene in the modified coal tar pitch is reduced by 30-70%, However, many modifiers are involved and the dosage is large, which makes the modification cost higher and limits the industrial application of coal tar pitch

[0009] Most of the above-mentioned coal tar pitch modifiers are limited to polymers, and the dosage is about 20% of the coal tar pitch, or directly adding petroleum pitch to the coal tar pitch can more or less reduce the content of toxic substances in the coal pitch, but most of the process It is cumbersome, not only uses a large amount, but also is expensive, and the space for reducing toxicity is limited, which greatly limits the application of coal tar asphalt pavement