CN104909421A - Treatment method of high-concentration phenolic wastewater generated in lignite upgrading process - Google Patents

Abstract

The invention discloses a treatment method of high-concentration phenolic wastewater generated in a lignite upgrading process. The method comprises the following steps: high-concentration phenolic wastewater subjected to deacidification and ammonia removal enters a plurality of extraction columns connected in series, each extraction column uses a fresh extractant to perform counter-current extraction on the phenolic wastewater, and cross-flow extraction is formed between every two extraction columns. The extractant can be methyl isobutyl ketone, mesityl oxide or tert amyl methyl ether. The number of the extraction columns can be 2-4. The amounts of the fresh extractants in the extraction columns can be different. After the wastewater treated by the method is subjected to solvent stripping, the optimal COD (chemical oxygen demand) can be down to 4000 mg/L below, and the total phenol content is lower than 220ppm, thereby completely satisfying the demands for conventional subsequent biochemical treatment.

Description

A treatment method for high-concentration phenol-containing wastewater produced during lignite upgrading

technical field

The invention belongs to the field of treatment and recovery methods for high-concentration phenol-containing wastewater, and in particular relates to a treatment method for high-concentration phenol-containing wastewater produced in the upgrading process of lignite.

Background technique

Lignite is the coal with the lowest degree of coalification, but it takes tens of millions of years to form, and it is a precious non-renewable resource. Its coalification degree is between peat and bituminous coal, and has the characteristics of high moisture content, high oxygen content, high volatile matter, and low calorific value. If lignite is not upgraded, it will be difficult to use it later. Therefore, lignite upgrading has become the key to the efficient development and utilization of lignite. Coal is thermally decomposed through the coal dry distillation process at 500-1100 degrees Celsius under the condition of isolation of air to produce gas, tar, crude benzene and coke.

The wastewater produced by the lignite upgrading process is a kind of industrial organic wastewater containing volatile phenols, polycyclic aromatic hydrocarbons and heterocyclic compounds such as oxygen, sulfur, nitrogen, high COD, high phenol value, high ammonia nitrogen, and is difficult to treat. Lignite upgrading wastewater has more complex components and higher content than that produced by Lurgi furnace or BGL furnace. COD can be as high as 50,000-120,000, total phenols are 12,000-21,000ppm, and the content of polyphenols is between 6,000-15,000ppm. Chinese patent CN102506575B is a very general treatment method, which uses high-temperature incineration to perform harmless treatment of wastewater with a water content of at least 90%. The ammonia nitrogen, sulfur, polyphenols and some macromolecular organic substances in the wastewater cannot be directly converted into No pollution, still will produce a lot of waste gas, and dissolve into water during the separation process with water vapor. And it is obviously not practical in application, there are high requirements for incineration temperature, low organic matter content in water, so the incineration value is not high, the actual treatment cost is too high, and the equipment requirements are higher when the treatment volume is large, etc. At present, there are very few literatures on the method of treating high-concentration phenolic ammonia wastewater produced by lignite upgrading by chemical unit operation method, and it is difficult to reduce COD and total phenols to the ideal level by using the conventional extraction method of high-concentration phenolic ammonia recovery to treat lignite upgrading wastewater. Therefore, according to the water quality of high-concentration phenol ammonia wastewater in the lignite upgrading process, the high-concentration phenol-containing wastewater after deacidification and deamination, providing an effective dephenolization technology to recover crude phenol products is an urgent problem in the coal chemical industry for lignite upgrading. environmental protection issues.

Contents of the invention

The object of the present invention is to provide a treatment method for high-concentration phenol-containing wastewater produced during the lignite upgrading process, which is also applicable to other wastewater treatment with higher polyphenol content. Its idea is to integrate cross-current extraction and counter-current extraction, which has a good effect on this type of wastewater with high COD and high polyphenol content.

A treatment method for high-concentration phenol-containing wastewater produced during the lignite upgrading process, the method is to conduct continuous countercurrent and cross-current integrated extraction of high-concentration phenol-containing wastewater through several extraction towers to obtain dephenolized wastewater and an extraction mixture, specifically The process is:

The high-concentration phenol-containing wastewater enters the first extraction tower from the upper part of the first extraction tower, and the first extraction agent enters the first extraction tower from the bottom of the first extraction tower, and the high-concentration phenol-containing wastewater passes through the first extraction tower and the first After the continuous countercurrent extraction of the extractant, the waste water and extract I after the first extraction are obtained; the waste water after the first extraction comes out of the first extraction tower, and enters the second extraction tower from the upper part of the second extraction tower. The bottom of the second extraction tower enters the second extraction tower, and the waste water after the first extraction and the second extraction agent are continuously extracted in the second extraction tower to obtain the waste water and extract II after the second extraction; the waste water after the second extraction According to the same method, continue to enter the subsequent extraction tower and perform continuous countercurrent extraction with the extractant to obtain the dephenolized wastewater and the extraction mixture after mixing the extracts.

According to requirements, the above method can end the extraction process after the secondary extraction, the wastewater after the secondary extraction is the dephenolization wastewater, and the mixture of the extract I and the extract II is the extraction mixture.

In the above method, fresh extractant and high-concentration phenol-containing wastewater are used for countercurrent extraction in each extraction tower, and cross-flow extraction is formed between the extraction towers.

The extractant that enters each extraction tower is a fresh extractant, and the fresh extractant includes a newly purchased extractant, a recycled extractant, and a mixture of the two. The volume of extractant entering each extraction tower can be the same or different.

The high-concentration phenol-containing wastewater is high-concentration phenol-containing wastewater after deacidification and deamination.

The number of extraction towers is 2-4, the extraction temperature is 40-80° C., and the high-concentration phenol-containing wastewater flows through each extraction tower in series. When the number of extraction towers is 2, the extraction process ends after the second extraction, and the wastewater after the second extraction is dephenolization wastewater; and so on, when the number of extraction towers is 3, the wastewater after three extractions is dephenolization wastewater Phenol wastewater; when the number of extraction towers is 4, the wastewater after four extractions is the dephenol wastewater.

The extraction stages of the extraction towers are all 2-10 stages, and the stages of each extraction tower can be different.

The extractant is methyl isobutyl ketone, mesityl oxide or methyl tert-amyl ether.

The volume ratio of the extractant entering each extraction tower to the high-concentration phenol-containing wastewater is 1:1-1:10.

The method also includes stripping the solvent from the dephenolized waste water through a raffinate phase rectification tower to obtain waste water that meets the requirements of conventional subsequent biochemical treatment, and passing the extraction mixture through a solvent recovery tower to recover the solvent to obtain crude phenol and recycled extractant.

After the dephenolized wastewater enters the raffinate phase rectification tower for solvent stripping, the COD can be as low as below 4000mg/L and the total phenols below 220ppm when the effluent index is the best, which can fully meet the requirements of conventional subsequent biochemical treatment.

The principle of the invention is: the continuous contact countercurrent extraction and the cross-current extraction are integrated together, and the advantages of the two are combined to realize the extraction of high-concentration total phenols and total COD. That is, multiple extraction towers are combined according to the idea of cross-flow extraction for dephenol extraction, and the liquid-liquid phase equilibrium is carried out in each independent extraction tower according to continuous countercurrent extraction; the extractant entering each extraction tower is fresh, and The waste water entering each extraction tower is passed in series. Simple multi-stage cross-flow extraction consumes a lot of extractant, and simple continuous contact countercurrent extraction can hardly meet the extraction effect. Therefore, the combination of the two can achieve the best effect of both extraction agent consumption and extraction effect.

Compared with the prior art, the present invention has the following advantages:

(1) The method of the present invention can reclaim the valuable by-product crude phenol in the high-concentration phenol-containing wastewater.

(2) Compared with the conventional chemical recovery system of the high-concentration phenolic ammonia wastewater produced by the Lurgi furnace or the BGL furnace, the extraction process of the present invention has been changed, which can greatly improve the extraction performance. The treatment capacity of the subsequent raffinate phase is the same as that of conventional phenol ammonia recovery. The treatment capacity of the extraction phase needs to be expanded according to the increase in the amount of extractant, but it can directly reduce the COD and total phenols of wastewater to the acceptable index of conventional biochemical treatment, eliminating the need for intermediate catalytic oxidation, etc. links.

(3) The method of the present invention adopts the method of cross-current extraction between the extraction towers and the internal countercurrent extraction of a single extraction tower, and the use of fresh extractant in each extraction tower can better enhance the extraction effect. For the high-concentration phenol-containing wastewater produced by lignite upgrading, COD60000-120000mg/L, total phenols 12000-21000ppm, COD can be reduced to below 4000mg/L, and total phenols are below 220ppm.

Description of drawings

Fig. 1 is a kind of typical process principle flow chart of the treatment method of the high-concentration phenol-containing wastewater produced by a kind of lignite upgrading process of the present invention, and two extraction towers are arranged. In the figure: 1—high concentration phenol-containing wastewater after deacidification and deamination, 2—first extraction tower, 3—waste water after primary extraction, 4—first extraction agent, 5—extract I, 6—second Extraction tower, 7—dephenol waste water, 8—second extractant, 9—extract II, 10—extractant, 11—extract mixture.

Detailed ways

The present invention will be further described in detail below with reference to the examples and drawings, but the implementation of the present invention is not limited thereto.

Fig. 1 is a kind of typical process principle flow chart of the treatment method of the high-concentration phenol-containing wastewater produced by a kind of lignite upgrading process of the present invention, and two extraction towers are arranged. In the figure: the extraction agent (10) is divided into the first extraction agent (4) and the second extraction agent (8); the high-concentration phenol-containing wastewater (1) after deacidification and deamination is extracted from the first extraction tower (2) The upper part enters the first extraction tower (2), and the first extraction agent (4) that enters from the first extraction tower (2) tower kettle is countercurrently extracted in the first extraction tower (2) to obtain the waste water (3 ) and extract I (5); the waste water (3) after the primary extraction that comes out from the first extraction tower (2) tower still enters the second extraction tower (6) from the second extraction tower (6) top, and from the second extraction tower (6) top The second extraction agent (8) that enters in the tower kettle of the second extraction tower (6) carries out countercurrent extraction in the second extraction tower (6), obtains dephenolized waste water (7) and extract II (9); dephenolized waste water ( 7) From the tower bottom of the second extraction tower (6), the waste water enters the raffinate phase rectification tower to strip the solvent and then enters the subsequent biochemical treatment unit; extract I (5) and extract II (9) are mixed to obtain The extraction mixture (11) enters the solvent recovery tower to recover the solvent to obtain crude phenol.

If necessary, the dephenolic waste water (7) can continue to enter the third, fourth... N extraction towers to reach the target value, and then the solvent stripping treatment. The amount of extractant entering each extraction tower can be different, but the same amount of extractant can be used for the convenience of operation. The extractant used can be methyl isobutyl ketone, mesityl oxide or methyl tert-amyl ether. The number of extraction towers is 2-4, the extraction temperature is between 40-80°C, and the volume ratio of extraction agent and waste water entering each extraction tower is 1:1-1:10. The extraction stages of each extraction tower are 2-10 stages, and the stages of each extraction tower can be different.

Example 1

Four extraction towers are connected to process the high-concentration phenol-containing wastewater produced during the lignite upgrading process. The extraction stages of each extraction tower are 5, using methyl isobutyl ketone as the extraction agent, and the extraction temperature is 40°C. Each extraction tower The volume ratio of the extraction agent to the high-concentration phenol-containing wastewater is 1:3, and the specific process is:

The high-concentration phenol-containing wastewater after deacidification and deamination enters from the upper part of the first extraction tower, the first extraction agent enters from the bottom of the first extraction tower, and the high-concentration phenol-containing wastewater passes through the first extraction tower and the first extraction The waste water and extract I after the first extraction are obtained after the continuous countercurrent extraction of the agent; the waste water after the first extraction comes out from the bottom of the first extraction tower and enters the upper part of the second extraction tower, and the second extraction agent enters from the bottom of the second extraction tower. The waste water after the extraction obtains the waste water after the second extraction and the extract II after continuous countercurrent extraction with the second extraction agent in the second extraction tower; It comes out and enters the subsequent extraction tower, and continues to carry out continuous countercurrent extraction with the extractant entering from the bottom of the extraction tower. After continuous countercurrent and cross-current extraction in 4 extraction towers, the dephenolized wastewater and the extraction mixture of various extracts are obtained.

In the present embodiment, the high-concentration phenol-containing wastewater COD120000mg/L (potassium dichromate method) and total phenol 21000ppm (iodine bromide method) after deacidification and deamination have a treatment capacity of 260 tons/hour. The resulting dephenolized wastewater enters the raffinate phase rectification tower to strip the solvent, and finally the obtained wastewater has a COD as low as 4500 mg/L and a total phenol of 220 ppm.

Example 2

Two extraction towers are connected to process the high-concentration phenol-containing wastewater produced during the lignite upgrading process. The extraction stages of each extraction tower are 5, and methyl isobutyl ketone is used as the extraction agent. The extraction temperature is 65°C. Each extraction tower The volume ratio of the extraction agent to the high-concentration phenol-containing wastewater is 1:4, and the specific process is:

The high-concentration phenol-containing wastewater after deacidification and deamination enters the first extraction tower from the upper part of the first extraction tower, and is countercurrently extracted with the first extractant that enters from the bottom of the first extraction tower in the first extraction tower to obtain a The waste water and extract I; The waste water after the extraction from the first extraction tower still enters the second extraction tower from the second extraction tower top, and the second extractant that enters from the second extraction tower still Countercurrent extraction is carried out in the second extraction tower to obtain dephenolized wastewater and extract II.

In this example, the high-concentration phenol-containing wastewater after deacidification and deamination has a COD of 60,000 mg/L, a total phenol of 15,000 ppm, and a treatment capacity of 260 tons/hour. After the obtained dephenolic wastewater enters the raffinate phase rectification tower to strip the solvent, the COD of the finally obtained wastewater is as low as 4000mg/L and the total phenols are 260ppm.

Example 3

Two extraction towers are connected to process the high-concentration phenol-containing wastewater generated during lignite upgrading. The volume ratio of the extraction agent of the tower to the high-concentration phenol-containing wastewater is 1:4, and the specific process is as follows:

The high-concentration phenol-containing wastewater after deacidification and deamination enters the first extraction tower from the upper part of the first extraction tower, and is countercurrently extracted with the first extractant that enters from the bottom of the first extraction tower in the first extraction tower to obtain a The waste water and extract I; The waste water after the extraction from the first extraction tower still enters the second extraction tower from the second extraction tower top, and the second extractant that enters from the second extraction tower still Countercurrent extraction is carried out in the second extraction tower to obtain dephenolized wastewater and extract II.

In this example, the high-concentration phenol-containing wastewater after deacidification and deamination has a COD of 60,000 mg/L, a total phenol of 15,000 ppm, and a treatment capacity of 260 tons/hour. The resulting dephenolized wastewater enters the raffinate phase rectification tower to strip the solvent, and the finally obtained wastewater has COD as low as 6500mg/L and total phenols as low as 420ppm.

Example 4

Two extraction towers are connected to process the high-concentration phenol-containing wastewater produced during the lignite upgrading process. The number of extraction stages in each extraction tower is 5, and mesityl oxide is used as the extraction agent. The extraction temperature is 65°C. The volume ratio of extractant to high-concentration phenol-containing wastewater is 1:4, and the specific process is:

The high-concentration phenol-containing wastewater after deacidification and deamination enters the first extraction tower from the upper part of the first extraction tower, and is countercurrently extracted with the first extractant that enters from the bottom of the first extraction tower in the first extraction tower to obtain a The waste water and extract I; The waste water after the extraction from the first extraction tower still enters the second extraction tower from the second extraction tower top, and the second extractant that enters from the second extraction tower still Countercurrent extraction is carried out in the second extraction tower to obtain dephenolized wastewater and extract II.

In this example, the high-concentration phenol-containing wastewater after deacidification and deamination has a COD of 60,000 mg/L, a total phenol of 15,000 ppm, and a treatment capacity of 260 tons/hour. After the obtained dephenolic wastewater enters the raffinate phase rectification tower to strip the solvent, the COD of the finally obtained wastewater is as low as 6100mg/L and the total phenols are 390ppm.

Example 5

Three extraction towers are connected to process the high-concentration phenol-containing wastewater produced during the lignite upgrading process. The extraction stages of each extraction tower are 5, and methyl isobutyl ketone is used as the extraction agent. The extraction temperature is 60°C. Each extraction tower The volume ratio of the extraction agent to the high-concentration phenol-containing wastewater is 1:3, and the specific process is:

The high-concentration phenol-containing wastewater after deacidification and deamination enters from the upper part of the first extraction tower, the first extraction agent enters from the bottom of the first extraction tower, and the high-concentration phenol-containing wastewater passes through the first extraction tower and the first extraction The waste water and extract I after the first extraction are obtained after the continuous countercurrent extraction of the agent; the waste water after the first extraction comes out from the bottom of the first extraction tower and enters the upper part of the second extraction tower, and the second extraction agent enters from the bottom of the second extraction tower. The waste water after the extraction obtains the waste water after the second extraction and the extract II after continuous countercurrent extraction with the second extraction agent in the second extraction tower; It comes out and enters the subsequent extraction tower, and continues to carry out continuous countercurrent extraction with the extractant entering from the bottom of the extraction tower. After continuous countercurrent and cross-current extraction in three extraction towers, the dephenolized wastewater and the extraction mixture mixed with each extract are obtained.

In this example, the high-concentration phenol-containing wastewater after deacidification and deamination has a COD of 75890mg/L, a total phenol of 19560ppm, and a treatment capacity of 140 tons/hour. The resulting dephenolized wastewater enters the raffinate phase rectification tower to strip the solvent, and the finally obtained wastewater has a COD as low as 4000mg/L and a total phenol of 280ppm.

Example 6

Two extraction towers are connected to process the high-concentration phenol-containing wastewater produced during the lignite upgrading process. The extraction stages of each extraction tower are 10, and methyl isobutyl ketone is used as the extraction agent. The extraction temperature is 80°C. Each extraction tower The volume ratio of the extraction agent to the high-concentration phenol-containing wastewater is 1:2, and the specific process is:

The high-concentration phenol-containing wastewater after deacidification and deamination enters the first extraction tower from the upper part of the first extraction tower, and is countercurrently extracted with the first extractant that enters from the bottom of the first extraction tower in the first extraction tower to obtain a The waste water and extract I; The waste water after the extraction from the first extraction tower still enters the second extraction tower from the second extraction tower top, and the second extractant that enters from the second extraction tower still Countercurrent extraction is carried out in the second extraction tower to obtain dephenolized wastewater and extract II.

In this example, the high-concentration phenol-containing wastewater after deacidification and deamination has a COD of 75890mg/L, a total phenol of 19560ppm, and a treatment capacity of 140 tons/hour. After the obtained dephenolic wastewater enters the raffinate phase rectification tower to strip the solvent, the COD of the finally obtained wastewater is as low as 6810mg/L and the total phenols are 528ppm.

Example 7

Four extraction towers are connected to process the high-concentration phenol-containing wastewater produced during lignite upgrading. Each extraction tower has two extraction stages, using methyl isobutyl ketone as the extraction agent, and the extraction temperature is 40°C. Each extraction tower The volume ratio of the extraction agent to the high-concentration phenol-containing wastewater is 1:2, and the specific process is:

The high-concentration phenol-containing wastewater after deacidification and deamination enters from the upper part of the first extraction tower, the first extraction agent enters from the bottom of the first extraction tower, and the high-concentration phenol-containing wastewater passes through the first extraction tower and the first extraction The waste water and extract I after the first extraction are obtained after the continuous countercurrent extraction of the agent; the waste water after the first extraction comes out from the bottom of the first extraction tower and enters the upper part of the second extraction tower, and the second extraction agent enters from the bottom of the second extraction tower. The waste water after the extraction obtains the waste water after the second extraction and the extract II after continuous countercurrent extraction with the second extraction agent in the second extraction tower; It comes out and enters the subsequent extraction tower, and continues to carry out continuous countercurrent extraction with the extractant entering from the bottom of the extraction tower. After continuous countercurrent and cross-current extraction in 4 extraction towers, the dephenolized wastewater and the extraction mixture of various extracts are obtained.

In this example, the high-concentration phenol-containing wastewater after deacidification and deamination has a COD of 75890mg/L, a total phenol of 19560ppm, and a treatment capacity of 140 tons/hour. After the obtained dephenolic wastewater enters the raffinate phase rectification tower to strip the solvent, the COD of the finally obtained wastewater is as low as 5211mg/L and the total phenols are 355ppm.

Comparative example 1

An extraction tower with 10 extraction stages is used to treat the high-concentration phenol-containing wastewater generated during the lignite upgrading process. Methyl isobutyl ketone is used as the extraction agent, the extraction temperature is 65°C, and the volume ratio of the extraction agent to the high-concentration phenol-containing wastewater is 1. : 2, the specific process is:

The high-concentration phenol-containing wastewater after deacidification and deamination enters from the upper part of the extraction tower, and the extractant enters from the bottom of the extraction tower. The high-concentration phenol-containing wastewater undergoes continuous countercurrent extraction with the extractant to obtain extracted wastewater and extracts.

In this comparative example, the high-concentration phenol-containing wastewater after deacidification and deamination has a COD of 60,000 mg/L, a total phenol of 15,000 ppm, and a treatment capacity of 260 tons/hour. The resulting dephenolized wastewater enters the raffinate phase rectification tower to strip the solvent, and finally the wastewater COD is as low as 7250mg/L and the total phenols are 580ppm.

Comparative example 2

A 10-stage cross-flow extraction process was used to treat the high-concentration phenol-containing wastewater produced during the lignite upgrading process. Methyl isobutyl ketone was used as the extraction agent, the extraction temperature was 65°C, and the volume ratio of the extraction agent to the high-concentration phenol-containing wastewater was 1:20. The specific process is:

After deacidification and deamination, the high-concentration phenol-containing wastewater and fresh extractant are put into the first extraction tank for stirring, and then the lower raffinate phase and the fresh extractant are put into the second extraction tank for stirring, and then the lower raffinate phase is again Enter the third extraction tank with the fresh extractant and stir and let it stand. In this way, the raffinate phase from the ninth extraction tank enters the tenth extraction tank and stirs and stands still. The raffinate phase is the waste water after dephenolization. The final product of the extraction phase is to collect the upper extract phases of each extraction kettle and mix them.

In this comparative example, the high-concentration phenol-containing wastewater after deacidification and deamination has a COD of 60,000 mg/L, a total phenol of 15,000 ppm, and a treatment capacity of 260 tons/hour. After the obtained dephenolic wastewater enters the raffinate phase rectification tower to strip the solvent, the COD of the finally obtained wastewater is as low as 13860mg/L and the total phenols are 2568ppm.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (7)

1. a treatment method for high-concentration phenol-containing wastewater produced by lignite upgrading process, characterized in that, the method is to carry out continuous countercurrent and cross-current integrated extraction of high-concentration phenol-containing wastewater through several extraction towers to obtain dephenolization Wastewater and extraction mixture, the specific process is: The high-concentration phenol-containing wastewater enters the first extraction tower from the upper part of the first extraction tower, and the first extraction agent enters the first extraction tower from the bottom of the first extraction tower, and the high-concentration phenol-containing wastewater passes through the first extraction tower and the first After the continuous countercurrent extraction of the extractant, the waste water and extract I after the first extraction are obtained; the waste water after the first extraction comes out of the first extraction tower, and enters the second extraction tower from the upper part of the second extraction tower. The bottom of the second extraction tower enters the second extraction tower, and the waste water after the first extraction and the second extraction agent are continuously extracted in the second extraction tower to obtain the waste water and extract II after the second extraction; the waste water after the second extraction According to the same method, continue to enter the subsequent extraction tower and perform continuous countercurrent extraction with the extractant to obtain the dephenolized wastewater and the extraction mixture after mixing the extracts. 2. The method for processing the high-concentration phenol-containing wastewater produced in a lignite upgrading process according to claim 1, wherein the high-concentration phenol-containing wastewater is high-concentration phenol-containing wastewater after deacidification and deamination. 3. the treatment method of the high-concentration phenol-containing wastewater that a kind of lignite upgrading process produces according to claim 1, is characterized in that, the number of described extraction tower is 2-4, and extraction temperature is 40-80 ℃, The high-concentration phenol-containing wastewater flows through the extraction towers in series. 4. The method for treating high-concentration phenol-containing wastewater produced in a lignite upgrading process according to claim 1, wherein the extraction stages of the extraction towers are 2-10 stages. 5. the processing method of the high-concentration phenolic wastewater that a kind of lignite upgrading process produces according to claim 1 is characterized in that, described extraction agent is methyl isobutyl ketone, mesityl oxide or methyl tert-amyl base ether. 6. the processing method of the high-concentration phenolic waste water that a kind of lignite upgrading process produces according to claim 1 is characterized in that, the extraction agent that enters each extraction tower and high-concentration phenolic waste water volume ratio are 1:1- 1:10. 7. the processing method of the high-concentration phenolic waste water that a kind of lignite upgrading process produces according to claim 1, is characterized in that, described method also comprises that dephenolic waste water is obtained by stripping solvent of raffinate phase rectification tower For wastewater that meets the requirements of conventional subsequent biochemical treatment, the extraction mixture is passed through a solvent recovery tower to recover the solvent to obtain crude phenol and recycled extractant.