CN114804473A - Device and method for reducing and treating coal chemical industry wastewater - Google Patents

Abstract

The invention relates to the field of wastewater treatment, and discloses a device and a method for coal chemical industry wastewater reduction treatment. The device for the coal chemical industry wastewater reduction treatment comprises a deacidification deamination tower, a concentration tower and an alkaline washing tower. The coal chemical industry wastewater reduction treatment method comprises the following steps: (1) performing deacidification and deamination treatment on the coal chemical industry wastewater to obtain acid gas, ammonia-containing water vapor and kettle liquid; (2) distilling and concentrating the kettle liquid to obtain a gaseous product and a concentrated phenol liquid; (3) and carrying out dephenolization treatment on the gaseous product by using alkali liquor to obtain dephenolized gas and washing liquor, and condensing the dephenolized gas to obtain low-pollution water. The method provided by the invention can ensure that the COD of the low-pollution water is below 2000mg/L, reduce the treatment load of the low-pollution water, reduce the wastewater amount to 5-70 wt% of the original water amount according to the requirement, and is beneficial to realizing the water balance of various process systems. Meanwhile, the invention has simple whole process flow and more thorough solution of the pollution problem of the waste water.

Description

Apparatus and method for reduction treatment of coal chemical wastewater

technical field

The invention relates to the field of wastewater treatment, in particular to a device and method for reducing the amount of coal chemical wastewater.

Background technique

In the composition of coal resources in my country, low-rank coals such as lignite and long flame coal account for more than 50%. Because low-rank coal has the characteristics of high moisture, high volatility and high activity, in-situ conversion is a more suitable utilization method. Encouraged by national policies, a large number of large-scale coal chemical projects using low-rank coal as raw materials have been invested in and constructed. These projects are of great significance to optimizing the comprehensive utilization of energy, promoting economic development, and can effectively enhance the national energy security capability.

Due to the short coal-forming time of low-rank coal, high moisture content and high volatile content, a large amount of phenol-containing wastewater will be generated during the drying, dry distillation, and gasification conversion processes. Depending on the properties of low-rank coal, conversion processes and products, 0.4-1.4 tons of phenol-containing wastewater will be generated for every ton of coal converted. At present, after the projects under construction in my country are put into operation, more than 200 million tons of phenol-containing wastewater will be generated every year. This part of the wastewater has a high pollution load and a complex composition. The COD is as high as 20000-80000mg/L, and more than 400 types of pollutants can be detected, including 5000-25000mg/L of phenols, 5000-15000mg/L of ammonia, and a large number of other pollutants. Long-chain alkanes and fatty acids, polycyclic aromatic hydrocarbons, quinolines, indole, pyridine and other heterocyclic compounds have strong biological toxicity and extremely poor biodegradability. The treatment of such wastewater has always been a world-class problem.

For this type of wastewater, most of the current methods are phenolic ammonia recovery - biochemical treatment - advanced treatment three links in series to deal with. That is, the chemical separation device is used to separate most of the pollutants such as phenols and other organic compounds, ammonia and acid gases in the wastewater to reduce the pollution load of the wastewater before entering the subsequent biochemical treatment device for biochemical treatment. The wastewater is reused for advanced treatment by ozone oxidation, adsorption and other processes. The whole treatment system has the problems of long process, large investment and high operating cost, and the stability of operation is still not ideal.

In order to simplify the treatment process, in theory, this kind of high-concentration phenol-containing wastewater can be used as pulping water for coal-water slurry or incinerated after coal blending, which can simply and completely solve the pollution problem of phenol-containing wastewater. However, this solution faces the problems of a large amount of phenol-containing wastewater, the inability to achieve water balance, and the high overall energy consumption. In order to cooperate with the realization of the scheme, it is urgent to provide a device and method for reducing the amount of coal chemical wastewater.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the problems of long process flow, large investment, high operating cost, large amount of phenol-containing wastewater, inability to achieve water balance, and high overall energy consumption in the existing coal chemical wastewater treatment system in the prior art, and provide a coal chemical industry. The device and method for reducing the amount of chemical waste water can simplify the overall treatment plan of coal chemical waste water, and solve the problem of treatment of this type of waste water more thoroughly with less investment.

In order to achieve the above purpose, the first aspect of the present invention provides a device for reducing the amount of coal chemical wastewater, including a deacidification and deamination tower, a concentration tower and an alkali washing tower, wherein the deacidification and deamination towers are respectively connected to the concentration towers and the alkaline washing tower, the concentration tower is communicated with the alkaline washing tower;

The deacidification and deamination tower is used for deacidification and deamination treatment of coal chemical wastewater to obtain acid gas, ammonia-containing steam and still liquid;

The concentration tower is used for distilling and concentrating the still liquid to obtain gaseous product and concentrated phenol liquid;

The alkaline washing tower is used for dephenolizing the gaseous product to obtain dephenolized gas and washing liquid, the washing liquid is returned to the deacidification and deamination tower, and the dephenolized gas is condensed to obtain low-pollution water.

A second aspect of the present invention provides a method for reducing the amount of coal chemical wastewater, comprising the following steps:

(1) carrying out deacidification and deamination treatment of coal chemical waste water to obtain acid gas, ammonia-containing steam and still liquid;

(2) described still liquid is carried out distillation and concentration, obtain gaseous product and concentrated phenol liquid;

(3) dephenolizing the gaseous product with alkaline solution to obtain dephenolized gas and washing liquid, and condensing the dephenolized gas to obtain low-pollution water.

Through the above-mentioned technical scheme, the present invention can obtain the following beneficial effects:

(1) The present invention can divide the phenol-containing wastewater from coal chemical industry into two parts: concentrated phenol solution and low-pollution water. The concentrated phenol liquid can be treated by coal slurry, incineration and other processes, and the low-pollution water can be simply biochemically treated or used as cooling water to make up water. Compared with the traditional treatment method of phenol-containing wastewater from coal chemical industry, the method provided by the present invention has a simple overall process and solves the pollution problem of wastewater more thoroughly.

(2) The present invention can ensure that the COD of the low-pollution water is below 2000 mg/L by using the alkaline washing tower to elute the organic substances such as phenols in the gaseous product, thereby reducing the processing load of the low-pollution water. Moreover, the washing liquid that has absorbed organic substances such as phenols enters the deacidification and deamination tower without secondary pollution.

(3) The present invention can reduce the waste water to 5-70wt% of the original water according to the demand, which is beneficial to realize the water balance of various process systems.

Description of drawings

FIG. 1 is a schematic diagram of a device for reducing the amount of coal chemical wastewater provided by the present invention.

Description of reference numerals

1. Deacidification and deamination tower 2. Concentration tower 3. Alkali washing tower

4. Storage tank 5. Built-in partial condenser 6. Wastewater feeding pipeline

7. The first cooler 8. The heat exchanger 9. The acid gas outlet pipeline

10. The first reboiler 11, the second reboiler 12, the outlet pipeline of concentrated phenol liquid

13. Alkali addition pipeline 14. Low pollution water outlet pipeline 15. Second cooler

Detailed ways

The endpoints of ranges and any values disclosed herein are not limited to the precise ranges or values, which are to be understood to encompass values proximate to those ranges or values. For ranges of values, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined with each other to yield one or more new ranges of values that Ranges should be considered as specifically disclosed herein.

A first aspect of the present invention provides a device for reducing the amount of coal chemical wastewater, comprising a deacidification and deamination tower, a concentration tower and an alkali washing tower, wherein the deacidification and deamination tower is respectively connected to the concentration tower and the alkali washing tower, Described concentration tower is communicated with alkali washing tower;

The deacidification and deamination tower is used for deacidification and deamination treatment of coal chemical wastewater to obtain acid gas, ammonia-containing steam and still liquid;

The concentration tower is used for distilling and concentrating the still liquid to obtain gaseous product and concentrated phenol liquid;

The alkaline washing tower is used for dephenolizing the gaseous product to obtain dephenolized gas and washing liquid, the washing liquid is returned to the deacidification and deamination tower, and the dephenolized gas is condensed to obtain low-pollution water.

In some embodiments of the present invention, a schematic diagram of a device for reducing the amount of coal chemical wastewater is shown in FIG. 1 . The device comprises a deacidification and deamination tower 1, a concentration tower 2, an alkali washing tower 3 and a storage tank 4, wherein the deacidification and deamination tower 1 is respectively connected to the concentration tower 2 and the alkali washing tower 3, and the concentration tower 2 is connected to The alkaline washing tower 3 is connected to the storage tank 4 .

In some embodiments of the present invention, the coal chemical wastewater feed pipeline 6 is connected to the upper part of the deacidification and deamination tower 1 through the first cooler 7 , and the coal chemical wastewater feed pipeline 6 is connected to the deacidification tower 1 through a heat exchanger 8 . The middle and upper part of acid deamination tower 1.

In some embodiments of the present invention, the acid gas outlet pipeline 9 is connected to the top of the deacidification and deamination tower 1, and the concentration tower 2 is connected to the bottom of the deacidification and deamination tower 1; 1. A side line is set up to produce ammonia-containing steam, which is used as a heat source for the concentration tower 2, and can continue to be refined into ammonia products.

In the present invention, after the ammonia-containing steam extracted from the side line of the deacidification and deamination tower 1 and the tower kettle liquid of the concentration tower 2 pass through the first reboiler 10 for heat exchange, the ammonia-containing steam itself is condensed to 80-120 ℃, The condensed ammonia-containing water vapor enters the subsequent segregation and absorption unit to be processed into ammonia products for sale.

In some embodiments of the present invention, the deacidification and deamination tower 1 is used for deacidification and deamination treatment of coal chemical wastewater, acid gas is obtained at the top of the tower, and still liquid is obtained at the bottom of the tower. The acid gas enters the incineration device, and the kettle liquid is pumped into the concentration tower 2.

In some embodiments of the present invention, the top of the concentration tower 2 is provided with a built-in partial condenser;

The concentration tower 2 is provided with a feed port, and the bottom of the deacidification and deamination tower 1 is connected to the feed port;

Preferably, the feed port is arranged at the lower part of the concentration tower 2, and a tray or packing is arranged inside the concentration tower 2 above the feed port so that the theoretical number of stages satisfies 3-5 stages. No tray or packing is provided inside the concentration tower 2 below the feed port.

In some embodiments of the present invention, the concentration tower 2 can be set to be single-effect or double-effect, which is not particularly limited in the present invention.

In some embodiments of the present invention, preferably, the bottom of the concentration column is provided with 3 outlets; wherein, the first outlet is connected to the bottom of one side of the concentration column 2 through the first reboiler 10; the second The outlet is connected to the bottom of the other side of the concentration tower 2 through the second reboiler 11 , and the third outlet is connected to the concentrated phenol liquid outlet pipeline 12 . Wherein, the first reboiler 10 uses the ammonia-containing steam as a heat source, and the second reboiler 11 can use a fresh heat source to supplement heat and realize flexible adjustment.

In some embodiments of the present invention, the concentration tower 2 is used for distilling and concentrating the still liquid produced by the deacidification and deamination tower 1, and gaseous products are obtained from the top of the concentration tower 2. A concentrated phenol liquid is obtained at the bottom; the concentrated liquid is sent out of the boundary area and can be used for coal-water slurry pulping or mixed with coal for incineration.

In some embodiments of the present invention, the alkaline washing tower 3 is provided with upper and lower circulating washing sections, both of which are provided with packing, and the theoretical stages of the two circulating washing sections are both 1-3. ;

The bottom of the alkali scrubbing tower 3 is connected to the bottom circulation return port of the alkali scrubbing tower 3 and the deacidification and deamination tower 1 respectively by the pump, and the middle side line of the alkali scrubbing tower 3 is connected to the upper circulation return port of the alkali scrubbing tower 3 by the pump; The alkali solution adding pipeline 13 is connected to the top of the alkali washing tower 3 .

In some embodiments of the present invention, the alkaline washing tower 3 is used for dephenolizing the gaseous product obtained from the concentration tower 2, and the top of the alkaline washing tower 3 obtains dephenolized gas, and the alkaline washing tower 3 The bottom of the tower gets the washing liquid. The washing liquid is returned to the deacidification and deamination tower 1, which will not cause secondary pollution and can improve the deamination effect at the same time.

In the present invention, by arranging the alkaline washing tower into upper and lower circulating washing sections, it can ensure that the gaseous product is fully contacted with the alkaline solution, and the organic substances such as phenols in the gaseous product can be washed out.

In some embodiments of the present invention, the top of the alkali washing tower 3 is connected to the storage tank 4 through the second cooler 15 ; the outlet of the storage tank 4 is connected to the low-pollution water outlet pipe 14 .

In some embodiments of the present invention, after the dephenolization gas extracted from the top of the alkali washing tower 3 is condensed by the second cooler 15 , low-pollution water is obtained and enters the storage tank 4 . The low-pollution water extracted from the storage tank 4 can enter the biochemical device for further treatment or be used as make-up water for circulating water.

A second aspect of the present invention provides a method for reducing the amount of coal chemical wastewater, comprising the following steps:

(1) carrying out deacidification and deamination treatment of coal chemical waste water to obtain acid gas, ammonia-containing steam and still liquid;

(2) described still liquid is carried out distillation and concentration, obtain gaseous product and concentrated phenol liquid;

(3) dephenolizing the gaseous product with alkaline solution to obtain dephenolized gas and washing liquid, and condensing the dephenolized gas to obtain low-pollution water.

In the present invention, through deacidification and deamination, distillation concentration and dephenolization, the wastewater of coal chemical industry is divided into two parts: concentrated phenol solution and low pollution water. Compared with the traditional treatment method of phenol-containing wastewater from coal chemical industry, the method provided by the present invention has a simple overall process and solves the pollution problem of wastewater more thoroughly.

In some embodiments of the present invention, the deacidification and deamination treatment is performed in a deacidification and deamination tower. Preferably, the process of deacidification and deamination treatment includes: dividing the coal chemical wastewater into cold and hot water from the upper part and the middle upper part of the deacidification and deamination tower into the tower, and controlling the gauge pressure at the top of the deacidification and deamination tower The temperature at the top of the tower is 0-0.4MPa, the temperature at the top of the tower is 35-65℃, the gauge pressure at the bottom of the tower is 0.02-0.42MPa, and the temperature at the bottom of the tower is 99-145℃. The acid gas extracted from the top of the deacidification and deamination tower enters the incineration device. The ammonia-containing water vapor extracted from the side line is used as the heat source of the concentration tower, and it is condensed to 80-120 ℃ and then enters the subsequent segregation and absorption device to be processed into ammonia products for sale. The liquid in the tower kettle of the deacidification and deamination tower is pumped to the concentration tower.

In some embodiments of the present invention, the distillation and concentration are carried out in a concentration tower, and the process of the distillation and concentration includes: sending the deacidified and deaminated still liquid into a concentration tower for vacuum distillation, and the top of the tower is collected The gaseous product is produced, and the concentrated solution obtained from the tower kettle is mixed with coal for incineration.

In some embodiments of the present invention, the conditions for distillation and concentration include: the reflux ratio of the concentration column is 0.05-0.2, the recovery rate of the top of the concentration column is 0.3-0.95, and the operating absolute pressure of the concentration column is 0.05-0.1 MPa.

In the present invention, the recovery rate of the top of the concentration tower refers to the ratio of the flow rate of the gaseous product extracted from the top of the concentration tower to the flow rate of the material entering the concentration tower. The reflux ratio of the concentration column refers to the ratio of the flow rate of the reflux liquid returned to the column by the built-in partial condenser to the flow rate of the gaseous product produced at the top of the column.

In some embodiments of the present invention, the dephenolization treatment is carried out in an alkali washing tower, and the process of the dephenolization treatment includes: passing the gaseous product obtained at the top of the concentration tower into the bottom of the alkali washing tower, and mixing with the alkali The liquid is countercurrently contacted, and the gaseous product after alkali washing is extracted from the upper part of the alkali washing tower, and condensed to obtain low-pollution water (or distillate), which is used as the make-up water for circulating water.

In some embodiments of the present invention, the lye is quantitatively replenished from the top of the alkaline washing tower, and the excess lye is pumped into the deacidification and deamination tower under the condition that the liquid level in the tower kettle is kept stable to improve the deamination effect. .

In some embodiments of the present invention, the conditions of the dephenolization treatment include: the liquid-gas mass ratio of the upper circulating washing section of the alkali washing tower is 5-20, and the liquid-gas mass ratio of the lower circulating washing section is 5-15; The operating absolute pressure of the washing tower is 0.05-0.1MPa. Wherein, the liquid-gas mass ratio refers to the mass ratio of lye and gaseous products in the alkaline scrubber.

In some embodiments of the present invention, preferably, the pressure of the alkaline washing column is the same as the pressure of the concentration column.

In some embodiments of the present invention, in step (3), the alkali solution is selected from NaOH solution with a concentration of 30-50wt%; the addition amount of the alkali solution is 0.3-1kg/t waste water (converted to 100wt% NaOH calculation).

In the present invention, in step (3), the lye needs to be preheated in advance, and the temperature of the lye should be consistent with the temperature of the gaseous product to ensure that the gaseous product will not be condensed in the lye too much middle.

The present invention will be described in detail below by means of examples.

Example 1

In a coal pyrolysis plant, the amount of phenolic wastewater from coal chemical industry is 100t/h, about 7500mg/L of phenol, 5000mg/L of ammonia, 3200mg/L of carbon dioxide, 20mg/L of hydrogen sulfide, and 38,000mg/L of COD. According to the process equipment flow chart of Fig. 1, the wastewater treatment of coal chemical industry is carried out, and the steps are as follows:

(1) Deacidification and deamination: The coal chemical wastewater is divided into cold and hot parts from the upper and middle upper parts of the deacidification and deamination tower, so that the surface pressure at the top of the tower is 0.4MPa, the temperature at the top of the tower is 65℃, and the bottom of the tower is The gauge pressure is 0.42MPa, the temperature at the bottom of the tower is 144-145℃, and the acid gas extracted from the top of the tower enters the incineration device. The ammonia-containing water vapor extracted from the side line is used as the heat source of the concentration tower. After being condensed to 120 °C, it enters the subsequent segregation and absorption device to be processed into ammonia products for sale. The liquid in the tower kettle of the deacidification and deamination tower is pumped to the concentration tower.

(2) Distillation concentration: the still liquid of the deacidification and deamination tower is sent into the concentration tower for vacuum distillation. There are 6 trays (theoretical stages are 3) above the feed inlet of the concentration tower, the operating absolute pressure is 0.05MPa, the top of the concentration tower is equipped with a built-in partial condenser, and the reflux ratio is controlled to be 0.05. The gaseous product is extracted from the top of the tower, and the recovery rate is 0.95. The concentrated liquid obtained from the tower still is mixed with coal and burned.

(3) alkali-eluting phenol: the gaseous product obtained at the top of the concentrated tower is passed into the bottom of the alkali-washing tower, and is in countercurrent contact with the lye, and the gaseous product after the alkali-washing is extracted from the top of the alkali-washing tower, and after condensation, the distillation column is obtained. The effluent is used as supplementary water for circulating water. Among them, the pressure of the alkali washing tower is the same as the pressure of the concentration tower. The lye is quantitatively replenished from the top of the alkaline washing tower. Under the condition that the liquid level of the tower kettle is kept stable, the excess lye is pumped into the deacidification and deamination tower to improve the deamination effect. The lye is 40% sodium hydroxide solution, and the added amount is 100kg/h. The theoretical stages of the upper and lower two circulating washing sections of the alkaline washing tower are both 1 stage. The liquid-gas mass ratio of the upper circulating washing section is 5, and the liquid-gas mass ratio of the lower circulating washing section is 5.

According to statistics, when the treatment capacity is 100t/h, the amount of distillate is about 95t/h, and the concentrated liquid is about 5t/h; the distillate contains about 350mg/L phenol, 95mg/L ammonia, and 1400mg/L COD. L. The waste water was reduced to 5wt% of the raw water. When the concentrated liquid is incinerated with coal blending, the desulfurization and denitrification load of the boiler does not increase significantly, and there is no secondary pollution.

Example 2

Treat the phenol-containing waste water of coal chemical industry according to the method of embodiment 1, the difference is that in step (1), the gauge pressure at the top of the deacidification and deamination tower is 0MPa, the temperature at the top of the column is 35°C, and the gauge pressure at the bottom of the tower is 0.02MPa , the temperature at the bottom of the tower is 99°C;

In step (2), the theoretical number of stages above the feed inlet of the concentration tower is 5, the operating pressure is an absolute pressure of 0.1 MPa, the reflux ratio is 0.2, and the recovery rate at the top of the tower is 0.3;

In step (3), the lye solution is 30% sodium hydroxide solution, and the added amount is 30kg/h. The theoretical stages of the upper and lower two circulating washing sections of the alkaline washing tower are both 3 stages. The liquid-gas mass ratio of the upper circulating washing section is 15, and the liquid-gas mass ratio of the lower circulating washing section is 15.

According to statistics, when the processing capacity is 100t/h, the amount of distillate is about 30t/h, and the concentrate is about 70t/h; the distillate contains about 120mg/L of phenol, 50mg/L of ammonia, and 760mg/L of COD. L. The waste water was reduced to 70 wt% of the raw water.

Example 3

Treat the phenol-containing waste water of coal chemical industry according to the method of Example 1, the difference is that in step (1), the gauge pressure at the top of the deacidification and deamination tower is 0.18MPa, the temperature at the top of the tower is 50°C, and the gauge pressure at the bottom of the tower is 0.2 MPa, the temperature at the bottom of the tower is 120℃;

In step (2), the theoretical number of stages above the feed inlet of the concentration tower is 4, the operating absolute pressure is 0.08MPa, the reflux ratio is 0.1, and the recovery rate at the top of the tower is 0.6;

In step (3), the alkali solution is 50% sodium hydroxide solution, and the added amount is 50kg/h. The theoretical stages of the upper and lower two circulating washing sections of the alkaline washing tower are both 2 stages. The liquid-gas mass ratio of the upper circulating washing section is 7, and the liquid-gas mass ratio of the lower circulating washing section is 8.

According to statistics, when the treatment capacity is 100t/h, the amount of distillate is about 60t/h, and the concentrated liquid is about 40t/h; the distillate contains about 260mg/L of phenol, 75mg/L of ammonia, and 950mg/L of COD. L. The waste water was reduced to 40 wt% of the raw water.

To sum up, using the device and method provided by the present invention to treat coal chemical wastewater can ensure that the COD of low-pollution water is below 2000 mg/L, and reduce the processing load of low-pollution water. Moreover, the waste water can be reduced to 5-70 wt% of the raw water amount according to the demand, which is beneficial to realize the water balance of various process systems. In the prior art, the three links of phenolic ammonia recovery-biochemical treatment-advanced treatment are generally used in series to treat coal chemical wastewater. According to statistics, when the treatment capacity is 100t/h, using the existing scheme, the phenolic ammonia recovery effluent can be recovered. COD is 1500-3000mg/L higher than this scheme, and most of the COD components are refractory pollutants with poor biodegradability, so the biochemical scale and investment are large, and the effluent needs to be further treated by advanced treatment devices. The total investment of the three links of phenolic ammonia recovery-biochemical treatment-advanced treatment is more than 250 million yuan, and by using the technical solution provided by the present invention, the scale of the biochemical device can be greatly reduced, the advanced treatment device can be cancelled, and the overall investment can be reduced by 40%. %above.

The preferred embodiments of the present invention have been described above in detail, however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, a variety of simple modifications can be made to the technical solutions of the present invention, including combining various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed in the present invention. All belong to the protection scope of the present invention.

Claims (10)

1. The device for reducing the coal chemical wastewater is characterized by comprising a deacidification and deamination tower, a concentration tower and an alkaline washing tower, wherein the deacidification and deamination tower is respectively communicated with the concentration tower and the alkaline washing tower, and the concentration tower is communicated with the alkaline washing tower;

the deacidification and deamination tower is used for carrying out deacidification and deamination treatment on the coal chemical wastewater to obtain acid gas, ammonia-containing water vapor and kettle liquid;

the concentration tower is used for distilling and concentrating the kettle liquid to obtain a gaseous product and a concentrated phenol liquid;

the alkaline tower is used for carrying out dephenolization treatment on the gaseous product to obtain dephenolized gas and washing liquid, the washing liquid returns to the deacidifying and deaminating tower, and the dephenolized gas is condensed to obtain low-pollution water.

2. The apparatus of claim 1, wherein the deacidification deamination tower is provided with a side draw for withdrawing the ammonia-containing water vapor for use as a heat source for the concentration tower and to enable continued refining to ammonia product.

3. The apparatus according to claim 1 or 2, wherein the top of the concentration column is provided with a built-in dephlegmator;

the concentration tower is provided with a feed inlet, and the bottom of the deacidification deamination tower is connected with the feed inlet;

the feed inlet is arranged at the lower part of the concentration tower, and trays or packing are arranged in the concentration tower above the feed inlet, so that the theoretical stage number can meet 3-5 stages.

4. The apparatus according to any one of claims 1 to 3, wherein the bottom of the concentration column is provided with a first reboiler and a second reboiler, the first reboiler using the ammonia-containing water vapor as a heat source, the second reboiler using an external heat source as a heat source; and the outlet of the tower kettle of the concentration tower is connected with a concentrated phenol liquid outlet pipeline.

5. The device according to any one of claims 1 to 4, wherein the alkaline tower is provided with an upper circulating washing section and a lower circulating washing section, the upper circulating washing section and the lower circulating washing section are both provided with packing, and the theoretical stages of the two circulating washing sections are 1-3 stages.

6. A coal chemical industry wastewater reduction treatment method is characterized by comprising the following steps:

(1) performing deacidification and deamination treatment on the coal chemical industry wastewater to obtain acid gas, ammonia-containing water vapor and kettle liquid;

(2) distilling and concentrating the kettle liquid to obtain a gaseous product and a concentrated phenol liquid;

(3) and carrying out dephenolization treatment on the gaseous product by using alkali liquor to obtain dephenolized gas and washing liquor, and condensing the dephenolized gas to obtain low-pollution water.

7. The method of claim 6, wherein the deacidification deamination process is performed in a deacidification deamination tower under conditions comprising: the gauge pressure at the top of the deacidification and deamination tower is 0-0.4MPa, the temperature at the top of the tower is 35-65 ℃, the gauge pressure at the bottom of the tower is 0.02-0.42MPa, and the temperature at the bottom of the tower is 99-145 ℃.

8. The process according to claim 6 or 7, wherein the distillation concentration is carried out in a concentration column, the conditions of the distillation concentration comprising: the reflux ratio of the concentration tower is 0.05-0.2, the extraction rate at the top of the concentration tower is 0.3-0.95, and the operation absolute pressure of the concentration tower is 0.05-0.1 MPa.

9. The method according to any one of claims 6 to 8, wherein the dephenolation treatment is carried out in a caustic scrubber under conditions comprising: the liquid-gas mass ratio of the upper section of the circulating washing section of the alkaline tower is 5-20, and the liquid-gas mass ratio of the lower section of the circulating washing section is 5-15; the operating absolute pressure of the alkaline washing tower is 0.05-0.1 MPa.

10. The method according to any one of claims 6-9, wherein the lye is selected from the group consisting of NaOH solutions with a concentration of 30-50 wt%; the addition amount of the alkali liquor is 0.3-1kg/t wastewater.

Images