阅读说明：本技术 一种分离中低温煤焦油中酚类物质的方法 (Method for separating phenolic substances in medium and low temperature coal tar ) 是由 闫燕 房峰 苏鹏飞 张强 王启超 曹峰 吴文雷 陈立江 于 2020-08-07 设计创作，主要内容包括：本发明属于化工行业分离纯化技术领域,具体涉及一种分离中低温煤焦油中酚类物质的方法,采用两部萃取分离工艺,分离出纯度大于99％的酚类物质,具体步骤如下：中低温煤焦油与混合萃取剂混合、沉降,得到富酚组分,富酚组分进入萃取塔,塔底重组分进入回收塔2,回收塔2塔顶组分再进入回收塔3,回收塔3塔底组分为酚类物质。本发明的分离工艺操作条件简单,萃取剂价格较低,性质较稳定,设备投资及能耗较低,酚类回收率高且萃取剂均可回用,没有三废产生。(The invention belongs to the technical field of separation and purification in the chemical industry, and particularly relates to a method for separating phenols in medium and low temperature coal tar, wherein two extraction separation processes are adopted to separate the phenols with the purity of more than 99%, and the specific steps are as follows: and mixing and settling the medium-low temperature coal tar and the mixed extracting agent to obtain a phenol-rich component, feeding the phenol-rich component into an extraction tower, feeding the heavy component at the bottom of the tower into a recovery tower 2, feeding the component at the top of the recovery tower 2 into a recovery tower 3, and feeding the component at the bottom of the recovery tower 3 into a phenolic substance. The separation process has the advantages of simple operation conditions, low cost of the extracting agent, stable property, low equipment investment and energy consumption, high phenol recovery rate, recycling of the extracting agent and no generation of three wastes.)

1. A method for separating phenolic substances in medium and low temperature coal tar is characterized in that two extraction separation processes are adopted to separate the phenolic substances with the purity of more than 99 percent, and the specific steps are as follows:

(1) the medium-low temperature coal tar is uniformly mixed with the mixed extracting agent A, B according to a certain proportion, and the mixture is settled and layered, wherein the upper layer is a non-phenolic substance 1, and the lower layer is a phenolic-rich solvent;

(2) the separated phenol-rich solvent enters an extraction tower from the upper end of the tower, and an extractant C enters the extraction tower from the lower end of the tower and is subjected to countercurrent extraction;

(3) the components at the top of the extraction tower enter a recovery tower 1, the components at the top of the recovery tower 1 are an extracting agent C and are recycled, and the components at the bottom of the extraction tower are non-phenolic substances 2;

(4) the components at the bottom of the extraction tower enter a recovery tower 2, the components at the bottom of the recovery tower 1 are an extracting agent A and are recycled, and the components at the top of the tower enter a recovery tower 3;

(5) the tower top component of the recovery tower 3 is a non-phenol substance 3, after the non-phenol substance 3 is stood for layering, the upper layer is a non-phenol substance 4, and the lower layer is an extracting agent B for recycling; the tower bottom component of the recovery tower is phenolic substances;

(6) the non-phenolic substances 1, 2 and 4 are used as oil blending components to blend the diesel oil;

the medium and low temperature coal tar contains 60-70% of phenolic substances and the balance of non-phenolic substances.

2. The method for separating phenolic substances from medium and low temperature coal tar according to claim 1, wherein the extracting agent A is: one of glycerol, ethylene glycol and diethylene glycol, and the extractant B is: water, triethylamine and organic acid solution.

3. The method for separating phenolic substances from medium and low temperature coal tar according to claim 1, wherein the extracting agent C is: n-hexane, isohexane, cyclohexane and acetonitrile.

4. The method for separating phenolic substances from medium and low temperature coal tar according to claim 1, wherein the mass ratio of the extracting agent A to the extracting agent B in the mixed extracting agent A, B is 2:1-10:1, and the mass ratio of the mixed extracting agent A, B to the medium and low temperature coal tar is 1:1-20: 1.

5. The method for separating phenolic substances from medium and low temperature coal tar according to claim 4, wherein the mass ratio of the extracting agent A to the extracting agent B in the mixed extracting agent A, B is 1:1-5: 1; the mass ratio of the mixed extracting agent A, B to the medium-low temperature coal tar is 5:1-15: 1.

6. The method for separating phenolic substances from medium and low temperature coal tar according to claim 1, wherein the mass ratio of the extracting agent C to the medium and low temperature coal tar is 1:1-20: 1.

7. The method for separating phenolic substances from medium and low temperature coal tar according to claim 6, wherein the mass ratio of the extracting agent C to the medium and low temperature coal tar is changed to 1: 1-5:1.

8. The method as claimed in claim 1, wherein the temperature at the top of the recovery column 1 is 67-72 ℃, the pressure at the top of the recovery column is 101.3-120Kpa, and the temperature at the bottom of the recovery column is 169-179 ℃.

9. The method as claimed in claim 1, wherein the temperature at the top of the recovery column 2 is 121 ℃, the pressure at the top of the recovery column is 15-35Kpa, and the temperature at the bottom of the recovery column is 230-240 ℃.

10. The method as claimed in claim 1, wherein the temperature at the top of the recovery column 3 is 87-89 ℃, the pressure at the top of the recovery column is 15-35Kpa, and the temperature at the bottom of the recovery column is 155-162 ℃.

Technical Field

The invention belongs to the technical field of separation and purification in the chemical industry, and particularly relates to a method for separating phenols in medium and low temperature coal tar.

Background

At present, medium-low temperature coal tar contains a large amount of phenolic substances, phenols and non-phenols are mostly separated by auxiliary methods such as alkali washing, acid washing neutralization and the like, the operation procedures are more and complicated, the product recovery rate is low, the amount of wastewater in the process is large, the subsequent sewage treatment cost is high, and the method is not beneficial to environmental protection.

Medium and low temperature coal tar is currently used for producing gasoline, the medium and low temperature coal tar contains more phenol products, the added value of phenols is higher, the boiling points of phenols and non-phenols are mutually crossed, the phenols and the non-phenols cannot be separated by common rectification, and the phenols and the non-phenols are mostly separated by auxiliary methods such as alkali washing, acid washing neutralization and the like, so that the operation procedures are more and complicated, the product recovery rate is low, and the amount of wastewater in the process is large.

Disclosure of Invention

For the technical problems existing at present, the invention provides a method for separating phenolic substances from medium and low temperature coal tar, which adopts two extraction and separation processes, has the advantages of simple operation conditions, lower price of an extracting agent, more stable properties, lower equipment investment and energy consumption, high recovery rate of phenols, reuse of the extracting agent and no generation of three wastes.

The technical scheme of the invention is as follows:

a method for separating phenolic substances from medium and low temperature coal tar, wherein the medium and low temperature coal tar is separated into the phenolic substances with the purity of more than 99% by adopting two extraction separation processes, and the specific steps are as follows:

(1) the medium-low temperature coal tar is uniformly mixed with the mixed extracting agent A, B according to a certain proportion, and the mixture is settled and layered, wherein the upper layer is a non-phenolic substance 1, and the lower layer is a phenolic-rich solvent;

(2) the separated phenol-rich solvent enters an extraction tower from the upper end of the tower, and an extractant C enters the extraction tower from the lower end of the tower and is subjected to countercurrent extraction;

(3) the components at the top of the extraction tower enter a recovery tower 1, the components at the top of the recovery tower 1 are an extracting agent C and are recycled, and the components at the bottom of the extraction tower are non-phenolic substances 2;

(4) the components at the bottom of the extraction tower enter a recovery tower 2, the components at the bottom of the recovery tower 1 are an extracting agent A and are recycled, and the components at the top of the tower enter a recovery tower 3;

(5) the tower top component of the recovery tower 3 is a non-phenol substance 3, after the non-phenol substance 3 is stood for layering, the upper layer is a non-phenol substance 4, and the lower layer is an extracting agent B for recycling; the tower bottom component of the recovery tower 3 is phenolic substances;

(6) the non-phenolic substances 1, 2 and 4 are used as oil blending components to blend the diesel oil;

the medium and low temperature coal tar contains 60-70% of phenolic substances and the balance of non-phenolic substances.

Preferably, the extractant a is: one of glycerol, ethylene glycol and diethylene glycol, and the extractant B is: water, triethylamine and organic acid solution.

Further preferably, extractant C is: n-hexane, isohexane, cyclohexane and acetonitrile.

Preferably, the mass ratio of the extracting agents A and B in the mixed extracting agent A, B is 2:1-10:1, and the mass ratio of the mixed extracting agent A, B to the medium-low temperature coal tar is 1:1-20: 1.

Further preferably, the mass ratio of the extracting agents A and B in the mixed extracting agent A, B is 1:1-5: 1; the mass ratio of the mixed extracting agent A, B to the medium-low temperature coal tar is 5:1-15: 1.

Preferably, the mass ratio of the extracting agent C to the medium-low temperature coal tar is 1:1-20: 1.

Further preferably, the mass ratio of the extracting agent C to the medium-low temperature coal tar is changed to 1:1-5: 1.

Preferably, the recovery column 1 has an overhead temperature of 67 to 72 ℃, an overhead pressure of 101.3 to 120Kpa (absolute) and a bottom temperature of 169-179 ℃.

Preferably, the temperature at the top of the recovery column 2 is 118-121 ℃, the pressure at the top of the recovery column is 15-35Kpa (absolute pressure), and the temperature at the bottom of the recovery column is 230-240 ℃.

Preferably, the temperature at the top of the recovery column 3 is 87 to 89 ℃, the pressure at the top of the column is 15 to 35Kpa (absolute pressure), and the temperature at the bottom of the column is 155-162 ℃.

Preferably, the extraction tower is a packed extraction tower, the recovery tower 1, the recovery tower 2 and the recovery tower 3 are packed recovery towers, and other types of extraction towers or recovery towers can be selected according to actual needs.

In the medium-low temperature coal tar, the non-phenolic substances contained in the medium-low temperature coal tar are other components such as 1, 3, 5-trimethylbenzene, o-xylene, n-dodecane, indane, 1-methylnaphthalene, pyridine, naphthalene, indene, methyl ethylbenzene, tetramethylbenzene and the like.

The invention provides a method for separating phenolic substances from medium and low temperature coal tar, which comprises the steps of firstly uniformly mixing the medium and low temperature coal tar with a mixed extracting agent A, B, settling and layering, wherein the upper layer is a non-phenolic substance 1, the lower layer is a phenol-rich solvent, the phenol-rich solvent enters an extraction tower from the upper end of the tower, the extracting agent enters the extraction tower from the lower end of the tower, light components at the top of the tower enter a recovery tower 1, components at the top of the recovery tower 1 are an extracting agent C, recycling is carried out, and components at the bottom of the recovery tower 1 are non-phenolic substances 2; the tower bottom component of the extraction tower enters a recovery tower 2, the tower bottom component of the recovery tower 2 is an extracting agent A and is recycled, the tower top component of the recovery tower 2 enters a recovery tower 3, the tower top component of the recovery tower 3 is subjected to standing and layering, the upper layer is a non-phenolic substance 4, the lower layer is an extracting agent B and is recycled, the tower bottom component of the recovery tower 3 is a phenolic substance, and the purity is higher than 99%; in the invention, the non-phenolic substances 1, 2 and 4 can all be used as oil blending components to blend the diesel oil. The extracting agent of the invention can be recycled, thus reducing the cost, reducing the waste of resources and avoiding the environmental pollution.

The invention adopts the mixed extractant and two extraction separation processes, the effect of separating phenolic substances from non-phenolic substances is optimal, which can not be realized by a single extractant and a single extraction separation; the boiling points of phenolic substances and non-phenolic substances are crossed, and the phenolic substances and the non-phenolic substances cannot be separated by ordinary rectification, but the high-purity phenolic substances can be separated by extracting twice and then passing through a recovery tower by the method; the method has the advantages of fewer and simple processes, high product recycling rate, more than 99% of the purity of the recycled phenolic substances, and capability of recycling the extracting agent in the process, thereby reducing the waste of resources.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The foregoing is only a preferred embodiment of this invention and it should be noted that modifications can be made by those skilled in the art without departing from the principles of the invention and these modifications should also be considered as within the scope of the invention.