CN102674608A - Method for recycling and treating high-concentration phenol/ammonia wastewater - Google Patents

Abstract

The invention discloses a method for recovering and treating high-concentration phenolic ammonia wastewater, which mainly includes the following steps: first, acid gas is used to saturate and absorb the high-concentration phenolic ammonia wastewater from which suspended solids and tar have been removed, and the wastewater enters an extraction tower after the pH value is lowered , carry out continuous countercurrent extraction; use single tower pressurized stripping process to deacidify, deammoniate and strip the solvent in the extracted raffinate phase, add alkali to the side line of the acid water stripping tower, discharge the acidic gas phase and extractant from the top of the tower, and discharge the acid gas phase and extractant from the top of the tower, and the lower side line Ammonia gas is obtained after three-stage fractional condensation; the extracted extract phase enters the rectifying phenol column to recover the extractant, and at the same time, crude phenol is obtained as a by-product. The acid gas used in the present invention is produced in the wastewater treatment process, and the internal circulation of the acid gas achieves the purpose of energy saving and environmental protection; and the deacidification, deamination and stripping of the solvent are simultaneously realized in the single tower gas stripping process, which can effectively treat high-concentration phenol Ammonia wastewater, recovering crude phenol and ammonia at the same time, the effluent can meet the requirements of subsequent conventional biochemical treatment, so that the final wastewater can be discharged up to standard.

Description

A kind of recycling treatment method of high-concentration phenolic ammonia wastewater

technical field

The invention belongs to the field of coal gasification wastewater treatment. The invention relates to a chemical treatment method of phenolic ammonia wastewater, in particular to a recovery and treatment method of high-concentration phenolic ammonia wastewater.

Background technique

The shortage of water resources has become one of the most severe challenges facing mankind today. my country is a country rich in coal resources, and there are many coal chemical companies. A large amount of industrial wastewater is produced in the process of coal coking, gas purification and chemical product recovery and refining. It must be treated in time and recycled to alleviate the current water shortage and environmental pollution. pressure from pollution. The water quality composition of coal gasification wastewater is complex and the concentration of pollutants is high. It usually contains a large amount of ammonia nitrogen, phenolic substances, single-ring aromatic hydrocarbons and polycyclic aromatic hydrocarbons, heterocyclic compounds containing nitrogen, sulfur, and oxygen, as well as some tar and cyanide. In the actual treatment of phenol-containing wastewater, for high-concentration phenol-containing wastewater, phenol should be recycled first; for wastewater with low phenol concentration and no recovery value or wastewater with residual phenol after recycling , it must be treated in a harmless manner to meet the discharge standards in order to achieve the unity of economic and environmental benefits.

For the treatment of high-concentration phenolic ammonia wastewater, it is difficult to meet the discharge standards by purely physical and chemical methods, and several different treatment methods are required to be used comprehensively. Usually, a combination of chemical separation pretreatment process and biochemical treatment is used. Part of the ash, oil, etc. are removed through precipitation, extraction, stripping and other units, and the valuable substance phenol ammonia is recovered, and then sent to biochemical treatment. The existing processes mainly include deacidification, extraction and dephenolization followed by deamination, and deacidification, deamination and solvent extraction and dephenolization.

Chinese patent 201010227835.2 proposes a method for treating phenol-containing wastewater from crushed coal pressurized gasification. This patent is aimed at deacidifying phenol-containing wastewater, which is washed by a carbon dioxide scrubber. After the acid gas is saturated, it enters the extraction tower for extraction and dephenolization. After dephenolization The waste water flows out from the bottom of the extraction tower and is pumped to the ammonia recovery section. However, the waste water contains a large amount of acid gas and a small amount of extractant, which is not considered to be removed, and directly enters the ammonia recovery section. Chinese patent 201010292208.7 also uses carbon dioxide saturated absorption first, and then extracts and removes phenols. The waste water after dephenolization is stripped to remove acid gas and ammonia, and the waste water at the bottom of the single tower is sent to the solvent stripping tower to recover the solvent. In the single tower process, the temperature of the tower kettle is 120~170°C to make the extractant in the water evaporate up and escape from the side line and the top of the single tower. The extraction and recovery are unreasonable, and the distribution coefficient of diisopropyl ether for polyphenol extraction is extremely low, and the total phenol content of the treated wastewater is not ideal.

Contents of the invention

The object of the present invention is to provide a kind of recovery treatment method of high-concentration phenolic ammonia waste water in view of the deficiencies in the prior art.

In order to achieve the above object, the present invention adopts the following technical solutions:

A kind of recovery processing method of high-concentration phenol ammonia waste water, comprises the following steps:

(1) Saturated absorption of acid gas

Control the temperature of the high-concentration phenolic ammonia wastewater from which suspended solids and tar have been removed at 30-70°C, enter the tower from the upper part of the acid gas absorption tower, and the acid gas enters from the lower part of the absorption tower, and saturate the high-concentration phenolic ammonia wastewater with acid gas Absorption, the acid gas-saturated phenol ammonia wastewater pH value is controlled to 7~8 and then enters the extraction tower; the acid gas can be recycled after being discharged from the top of the absorption tower;

(2) Solvent extraction dephenolization

Step (1) The treated acid gas-saturated phenolic ammonia wastewater enters the extraction tower from the upper part of the extraction tower, and conducts continuous countercurrent extraction with the extractant entering from the lower part of the extraction tower. The extraction temperature is 40~80 ° C; The volume ratio of the solvent is (4~8):1; the extracted extract phase enters the phenol tower of the rectification device to recover the solvent, and the raffinate phase enters the deacidification, deammoniation and solvent stripping section;

(3) Deacidification, deamination and solvent stripping by single tower pressurized stripping

Use single tower pressurized stripping to carry out deacidification, deammoniation and solvent stripping at the same time, specifically including: the raffinate phase obtained in step (2) is divided into two feeds, cold and hot, and enters the sour water stripping tower, and the temperature of the tower kettle is 130~170℃, the pressure of the tower kettle is 0.3~0.7MPa, the temperature of cold feed is 40~80℃, the temperature of hot feed is 120~155℃, the ratio of cold and hot feed is 1: (2~5); acid water vapor Alkali is added to the side line of the lifting tower, the gas phase and extraction agent are discharged from the top of the tower, and the effluent from the tower kettle enters the biochemical treatment section;

After the gas phase is extracted from the upper side line and cooled, the oil and water are separated, the extractant is recycled, and the condensate enters the waste water tank or the sour water stripping tower for dephenolization and deamination, and the solvent after dephenolization and deamination is recycled; the lower side line undergoes three-stage fractional condensation Finally, the ammonia gas is sent to the ammonia refining system. The operating pressure of the first stage partial condenser is 0.3~0.5MPa, and the operating temperature is 110~140°C. The operating pressure of the second stage partial condenser is 0.28~0.4MPa, and the operating temperature is 70~ 105°C, the operating pressure of the three-stage partial condenser is 0.2~0.35MPa, and the operating temperature is 30~50°C;

(4) Solvent recovery

Put the extraction phase obtained in step (2) into the phenol column for rectification to separate the extractant and crude phenol. The temperature of the bottom of the rectification phenol column is 190~220°C, the operating pressure is 0.1~0.2MPa, and the reflux ratio is 0.2~0.8. The final extractant is recycled, and the crude phenol is used as a by-product.

In the step (1) of the present invention, the acid gas used in the acid gas absorption tower is generated during the wastewater treatment process, and only needs to be additionally introduced when the device is initially opened. After the device is successfully operated, the acid gas is internally circulated. The specific circulation line is : A part of the acid gas produced by the top of the sour water stripping tower enters the acid gas absorption tower, and the rest enters the boiler or waste gas treatment device.

In step (1), the acid gas is carbon dioxide and/or hydrogen sulfide.

In step (2) of the present invention, the extractant is diisopropyl ether, methyl isobutyl ketone or methyl tert-amyl ether.

In step (3) of the present invention, sodium hydroxide solution or sodium carbonate solution is added when adding alkali to the side line, and the mass concentration of the sodium hydroxide solution or sodium carbonate solution is 15-50%.

In step (3), the gas phase discharged from the top of the sour water stripping tower contains acid gas, water vapor, ammonia gas and extractant. After cooling and oil-water separation, the oil phase extractant is recycled, and part of the acid gas is recycled into the acid gas absorption Tower, the rest goes to boiler or exhaust gas treatment unit.

In step (3), the gas phase extracted from the side line at the upper part of the sour water stripping tower mainly contains acid gas, water vapor, ammonia gas and extractant. After cooling and oil-water separation, the oil phase extractant is recycled, and the condensate enters the waste water tank or circulation Back to the single tower.

In step (3), the gas phase extracted from the side line at the lower part of the sour water stripping tower mainly contains acid gas, water vapor, ammonia gas and extraction agent. Cycle back to the single tower.

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

(1) Different from the traditional technology that specifically uses carbon dioxide saturation to absorb high-concentration phenolic ammonia wastewater, the acid gas used in the present invention is generated during the wastewater treatment process, and only needs to be additionally introduced when the device is initially opened. After the device is successfully operated, the acid gas Internal circulation can make the pH value of the wastewater entering the extraction tower lower than 8, creating a good acid-base environment for solvent extraction;

(2) According to the water quality of high-concentration phenolic ammonia wastewater, choose different extractants. For those with low polyphenol content, choose diisopropyl ether, and for those with high polyphenol content, choose methyl isobutyl ketone or methyl tert-amyl ether. And the amount of extractant is small, and the solvent is almost completely recovered in theory;

(3) A single-tower pressurized air strip is used to realize the acid gas and extractant from the top of the tower, the extractant and ammonia from the side line, and the water from the tower kettle directly enters the biochemical industry. This multi-functional single tower makes the process more concise and has deacidification The functions of tower, deamination tower and water tower;

(4) After the acid gas from the top of the single tower is separated from the extraction agent, part of the acid gas is circulated into the acid gas saturated absorption tower, and the rest is recovered in boilers or other devices;

(5) The wastewater in the present invention only needs to go through one heating and one cooling process, the heat exchange system is simpler and the energy consumption is lower;

(6) The method of the present invention can not only effectively remove phenol, ammonia and acid gas in wastewater, but also greatly reduce the content of other organic pollutants in wastewater, COD is lower than 3000mg·L ^-1 , and the pH value of the final effluent down to around 7.

Description of drawings

Fig. 1 is the schematic diagram of the device used in the recovery treatment method of the high concentration phenolic ammonia wastewater of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. But the protection scope of the present invention is not limited thereto.

The recovery treatment device of the high-concentration phenol ammonia waste water that the present invention adopts is as shown in Figure 1, mainly comprises: acid gas absorption tower 1, extraction tower 2, solvent tank 3, rectification phenol tower 4, acid water stripping tower 5, acid gas Separation tank 6, oil-water separation tank 7, primary flash tank 8, secondary flash tank 9 and tertiary flash tank 10.

The high-concentration phenol ammonia wastewater 11 enters from the upper part of the acid gas absorption tower 1, and absorbs the acid gas 15 entering from the lower part of the acid gas absorption tower 1 countercurrently. tank6. The waste water 27 from the lower part of the acid gas absorption tower enters from the upper part of the extraction tower 2, and carries out continuous countercurrent extraction with the extraction agent 28 which enters from the solvent tank 3 and enters from the lower part of the extraction tower 2. The extraction phase 29 in the upper part of the extraction tower 2 enters the rectification phenol tower 4 through heat exchange, and after the tower top gas phase 30 of the rectification phenol tower is cooled, the extractant is circulated back to the solvent tank, and partly refluxes to the rectification phenol tower, and the rectification phenol tower The crude phenol by-product 17 is obtained in the tower kettle. The waste water 31 at the outlet of the lower part of the extraction tower 2 is divided into two streams 32 and 33 , hot and cold, and enters the sour water stripper 5 , and the outlet water 26 of the sour water stripper 5 enters the biochemical section after cooling down. The side line of the sour water stripper 5 has an alkali-adding pipeline 18. The top gas phase 34 of the acid water stripping tower 5 enters the acid gas separation tank 6 after being cooled, and part of the acid gas 35 circulates to the acid gas absorption tower 1, and the remaining 21 goes to the boiler or acid gas treatment device, and the condensate of the acid gas separation tank 6 36 enters the oil-water separation tank 7 for further oil-water separation to separate the extractant 16 and the water phase 37. The side line 19 on the upper part of the acid-water stripper 5 also enters the oil-water separation tank 7 to separate the extraction agent 16 and the water phase 37 after heat exchange and cooling, and the extraction agent 16 separated by the oil-water separation tank 7 is recycled for use in the solvent removal tank 3 and the water phase 37 Mix with the condensate 25 of the condensing system and go to the waste water tank or the acid water stripper 4. The lower side line 20 of the sour water stripper 5 passes through the primary flash tank 8, the secondary flash tank 9 and the tertiary flash tank 10 to obtain ammonia gas 24 and condensate 25, and the ammonia gas 24 is further deammonized and refined, and the condensate 25 and the water phase 37 that comes out from the oil-water separation tank 7 are mixed into the waste water tank or the acid water stripper 4.

The acid gas absorption tower 1 is a packed extraction tower, the extraction tower 2 is a rotary disk extraction tower or a packed extraction tower, and the rectifying phenol tower 4 and the acid water stripping tower 5 are plate towers.

Example 1

The flow rate of phenolic ammonia wastewater at 37°C is 85 tons/hour, the total phenol content is 5599 mg·L ^-1 , of which polyphenol content is 1980 mg·L ^-1 , ammonia is 7975 mg·L ^-1 , carbon dioxide is 5000 mg·L ^-1 , hydrogen sulfide is 1000 mg·L ^{-1 1} , pH 9.3. Pass into the acid gas absorption tower, adjust the pH value of phenolic ammonia wastewater to 7.2, and then enter the extraction tower; the extraction tower is a packed extraction tower, the extraction agent is methyl isobutyl ketone, the extraction temperature is 40 ° C, and the volume ratio of the waste water extraction agent is 4: 1. The extracted extract phase enters the phenol column to recover the solvent, the tower kettle is 210°C, the tower top is 118°C, the operating pressure is 0.18MPa, and the reflux ratio is 0.2; The temperature at the top of the tower is 56°C, the temperature at the bottom of the tower is 160°C, the pressure at the bottom of the tower is 0.6MPa, the ratio of cold and hot feed is 1:3, the temperature of cold feed is 40°C, the temperature of hot feed is 150°C, and alkali is added to the side line of the acid water stripping tower , the gas phase and extractant are discharged from the top of the tower, and the effluent from the tower kettle enters the biochemical treatment section;

The gas phase extracted from the upper side line is cooled and the oil and water are separated, and the extractant is recycled; after the lower side line is subjected to three-stage fractional condensation, 85% (wt.) ammonia gas is obtained for further ammonia refinement. The operating pressure of the first-stage fractional condenser is 0.5MPa, and the operating temperature The operating pressure of the second-stage partial condenser is 0.4MPa, and the operating temperature is 90°C. The operating pressure of the third-stage partial condenser is 0.35MPa, and the operating temperature is 50°C.

In the treated wastewater, the total phenol was 220 mg·L ^-1 , the total ammonia was 312 mg·L ^-1 , the acid gas was trace amount, and the COD was 2140 mg·L ^-1 .

Example 2

The flow rate of phenolic ammonia wastewater at 37°C is 85 tons/hour, the total phenol content is 5599 mg·L ^-1 , of which polyphenol content is 1980 mg·L ^-1 , ammonia is 7975 mg·L ^-1 , carbon dioxide is 5000 mg·L ^-1 , hydrogen sulfide is 1000 mg·L ^{-1 1} , pH 9.3. Pass into the acid gas absorption tower, use the acid gas absorption tower to adjust the pH value of phenol ammonia wastewater to 8.0, and then enter the extraction tower; the extraction tower is a packed extraction tower, the extraction agent is methyl tert-amyl ether, the extraction temperature is 40 ° C, and the waste The solvent volume ratio is 7:1, the extracted extract phase enters the phenol tower to recover the solvent, the tower tank is 220°C, the tower top is 87°C, the operating pressure is 0.12MPa, and the reflux ratio is 0.8; the raffinate phase is divided into cold and hot feeds Enter the acid water stripping tower, the temperature at the top of the tower is 50°C, the temperature of the tower kettle is 170°C, the pressure of the tower kettle is 0.7MPa, the ratio of cold and hot feed is 1:3, the temperature of cold feed is 40°C, the temperature of hot feed is 155°C, the acid Alkali is added to the side line of the water stripping tower, the gas phase and extraction agent are discharged from the top of the tower, and the effluent from the tower kettle enters the biochemical treatment section;

The upper side line is drawn out, cooled and separated from oil and water, and the extractant is recycled; after the lower side line is subjected to three-stage fractional condensation, 90% (wt.) ammonia gas is obtained for further ammonia refinement. The operating pressure of the first-stage fractional condenser is 0.4MPa, and the operating temperature is 110°C, the operating pressure of the second stage partial condenser is 0.35MPa, the operating temperature is 70°C, the operating pressure of the third stage partial condenser is 0.2MPa, and the operating temperature is 30°C.

In the treated wastewater, the total phenol was 320 mg·L ^-1 , the total ammonia was 268 mg·L ^-1 , the acid gas was trace, and the COD was 2490 mg·L ^-1 .

Example 3

The flow rate of phenolic ammonia wastewater at 92°C is 85 tons/hour, the total phenol content is 5140mg·L ^-1 , of which polyphenol content is 1800mg·L ^-1 , ammonia is 8500mg·L ^-1 , carbon dioxide is 4500mg·L ^-1 , hydrogen sulfide is 80mg·L ^{-1 1} , pH 10.1. After the wastewater is cooled to 55°C, it is passed into the acid gas absorption tower and the acid gas absorption tower is used to adjust the pH value of the phenolic ammonia wastewater to 8.0 before entering the extraction tower; the extraction tower is a packed extraction tower, the extraction agent is methyl isobutyl ketone, and the extraction temperature 58°C, the volume ratio of waste water extractant is 5.5:1, the extracted extract phase enters the phenol tower to recover the solvent, the bottom of the tower is 210°C, the top of the tower is 119°C, the operating pressure is 0.1MPa, and the reflux ratio is 0.5; the raffinate phase is divided into cold, The two hot feeds enter the sour water stripping tower, the temperature at the top of the tower is 48°C, the temperature of the tower bottom is 165°C, the pressure of the bottom of the tower is 0.65MPa, the ratio of cold and hot feed is 1:3, the temperature of cold feed is 58°C, and the temperature of hot feed is 58°C. The temperature is 140°C, alkali is added to the side line of the acid water stripping tower, the gas phase and extraction agent are discharged from the top of the tower, and the water from the tower kettle enters the biochemical treatment section;

The upper side line is drawn out, cooled and separated from oil and water, and the extractant is recycled; after the lower side line is subjected to three-stage fractional condensation, 82% (wt.) ammonia gas is obtained for further ammonia refinement. The operating pressure of the first-stage fractional condenser is 0.45MPa, and the operating temperature is 128°C, the operating pressure of the second stage partial condenser is 0.35MPa, the operating temperature is 90°C, the operating pressure of the third stage partial condenser is 0.2MPa, and the operating temperature is 36°C.

In the treated wastewater, the total phenol was 240 mg·L ^-1 , the total ammonia was 298 mg·L ^-1 , the acid gas was trace, and the COD was 2230 mg·L ^-1 .

Example 4

The flow rate of phenol ammonia wastewater at 60°C is 85 tons/hour, the content of unit phenol is 5550mg·L ^-1 , ammonia is 8500mg·L ^-1 , carbon dioxide is 4500mg·L ^-1 , hydrogen sulfide is 80mg·L ^-1 , and the pH value is 9.8. Pass into the acid gas absorption tower, use the acid gas absorption tower to adjust the pH value of the phenolic ammonia wastewater to 7.8, and then enter the extraction tower; the extraction tower is a rotary extraction tower, the extraction agent is diisopropyl ether, the extraction temperature is 60 ° C, the volume The ratio is 4:1, the extraction phase after extraction enters the phenol tower to recover the solvent, the tower tank is 190°C, the tower top is 68°C, the operating pressure is 0.2MPa, and the reflux ratio is 0.6; the raffinate phase is divided into cold and hot two feeds into the acid Water stripping tower, tower top temperature 55°C, tower bottom temperature 130°C, tower bottom pressure 0.3MPa, cold and hot feed ratio 1:3, cold feed temperature 60°C, hot feed temperature 120°C, sour water stripping Alkali is added to the side line of the tower, the gas phase and extractant are discharged from the top of the tower, and the effluent from the tower kettle enters the biochemical treatment section;

The upper side line is drawn out, cooled and separated from oil and water, and the extractant is recycled; after the lower side line is subjected to three-stage fractional condensation, 75% (wt.) ammonia gas is further fed into ammonia refinement. The operating pressure of the first-stage fractional condenser is 0.3MPa, and the operating temperature The operating pressure of the second-stage partial condenser is 0.28MPa, and the operating temperature is 90°C. The operating pressure of the third-stage partial condenser is 0.1MPa, and the operating temperature is 30°C.

In the treated wastewater, unit phenol was 186 mg·L ^-1 , total ammonia was 350 mg·L ^-1 , acid gas was trace, and COD was 2983 mg·L ^-1 .

Example 5

The flow rate of phenolic ammonia wastewater at 92°C is 85 tons/hour, the total phenol content is 5140mg·L ^-1 , of which polyphenol content is 1800mg·L ^-1 , ammonia is 8500mg·L ^-1 , carbon dioxide is 4500mg·L ^-1 , hydrogen sulfide is 80mg·L ^{-1 1} , pH 10.1. After the wastewater is cooled to 70°C, it is passed into the acid gas absorption tower, and the acid gas absorption tower is used to adjust the pH value of the phenolic ammonia wastewater to 8.0 before entering the extraction tower; the extraction tower is a packed extraction tower, and the extraction agent is methyl tert-amyl ether. The extraction temperature is 72°C, the volume ratio of the waste water extractant is 5.5:1, the extracted extract phase enters the phenol tower to recover the solvent, the tower kettle is 210°C, the tower top is 88°C, the operating pressure is 0.15MPa, and the reflux ratio is 0.5; the raffinate phase is divided into The cold and hot feeds enter the sour water stripping tower, the temperature at the top of the tower is 48°C, the temperature of the tower kettle is 165°C, the pressure of the tower kettle is 0.65MPa, the ratio of cold and hot feeds is 1:5, the temperature of the cold feed is 72°C, and the temperature of the hot The feed temperature is 150°C, alkali is added to the side line of the acid water stripping tower, the gas phase and extractant are discharged from the top of the tower, and the effluent from the tower kettle enters the biochemical treatment section;

The upper side line is drawn out, cooled and oil-water separated, and the extractant is recycled; the lower side line is subjected to three-stage fractional condensation to obtain 82% (wt.) ammonia for further ammonia refinement. The operating pressure of the first-stage fractional condenser is 0.43MPa, and the operating temperature is 127°C, the operating pressure of the second stage partial condenser is 0.35MPa, the operating temperature is 89°C, the operating pressure of the third stage partial condenser is 0.12MPa, and the operating temperature is 32°C.

In the treated wastewater, the total phenol was 264 mg·L ^-1 , the total ammonia was 310 mg·L ^-1 , the acid gas was trace amount, and the COD was 2642 mg·L ^-1 .

Example 6

The flow rate of phenolic ammonia wastewater at 92°C is 100 tons/hour, the total phenol content is 5140mg·L ^-1 , of which polyphenol content is 1800mg·L ^-1 , ammonia is 8500mg·L ^-1 , carbon dioxide is 4500mg·L ^-1 , hydrogen sulfide is 80mg·L ^{-1 1} , pH 10.1. After the wastewater is cooled to 70°C, it is passed into the acid gas absorption tower, and the acid gas absorption tower is used to adjust the pH value of the phenolic ammonia wastewater to 7.4 before entering the extraction tower; the extraction tower is a packed extraction tower, and the extraction agent is methyl isobutyl ketone. The temperature is 80°C, the volume ratio of the wastewater extractant is 8:1, the extracted extract phase enters the phenol tower to recover the solvent, the bottom of the tower is 210°C, the top of the tower is 116°C, the operating pressure is 0.17MPa, and the reflux ratio is 0.8; the raffinate phase is divided into cold , The hot two feeds enter the acid water stripping tower, the temperature at the top of the tower is 86°C, the temperature of the tower bottom is 170°C, the pressure of the bottom of the tower is 0.7MPa, the ratio of cold and hot feed is 1:5, the temperature of cold feed is 80°C, and the temperature of hot feed is 80°C. The feed temperature is 155°C, alkali is added to the side line of the sour water stripping tower, the gas phase and extractant are discharged from the top of the tower, and the effluent from the tower kettle enters the biochemical treatment section;

The upper side line is drawn out, cooled and separated from oil and water, and the extractant is recycled; after the lower side line is subjected to three-stage fractional condensation, 82% (wt.) ammonia gas is obtained for further ammonia refinement. The operating pressure of the first-stage fractional condenser is 0.5 MPa, and the operating temperature is 140°C, the operating pressure of the second stage partial condenser is 0.4MPa, the operating temperature is 105°C, the operating pressure of the third stage partial condenser is 0.35MPa, and the operating temperature is 50°C.

In the treated wastewater, the total phenol was 334 mg·L ^-1 , the total ammonia was 189 mg·L ^-1 , the acid gas was trace, and the COD was 2746 mg·L ^-1 .

Claims (8)

1. a high-concentration phenol and ammonia Wastewater Recovery treatment process is characterized in that, may further comprise the steps:

(1) sour gas saturated absorption

With the high-concentration phenol ammonia waste water controlled temperature of removing suspended substance, tar is 30 ~ 70 ℃; Get in the tower from acid gas absorption tower top; Sour gas gets into from the bottom, absorption tower; By sour gas the high-concentration phenol ammonia waste water is carried out saturated absorption, the phenol ammonia waste water pH value that sour gas is saturated is controlled to be 7 ~ 8 backs and gets into extraction tower; Sour gas can be recycled after discharging from the top, absorption tower;

(2) SX dephenolize

The phenol ammonia waste water that sour gas after step (1) is handled is saturated gets in the extraction tower from extraction tower top, carries out continuous countercurrent extraction with the extraction agent that gets into from the extraction tower bottom, and extraction temperature is 40 ~ 80 ℃; The volume ratio of phenol ammonia waste water and extraction agent is (4 ~ 8): 1; Extraction phase after the extraction gets into rectifier unit phenol tower and reclaims solvent, and extracting phase gets into depickling deamination and solvent stripping workshop section;

(3) single tower pressurization stripping carries out depickling deamination and solvent stripping

Adopt single tower pressurization stripping to carry out depickling deamination and solvent stripping simultaneously; Specifically comprise: the extracting phase that step (2) is obtained is divided into hot and cold two bursts of chargings entering sour water stripping (SWS) tower; Tower still temperature is 130 ~ 170 ℃, and tower still pressure is 0.3 ~ 0.7MPa, and the cold feed temperature is 40 ~ 80 ℃; Hot feed is 120 ~ 155 ℃, and hot and cold charge ratio is 1: (2 ~ 5); Sour water stripping (SWS) tower side line adds alkali, and cat head is discharged gas phase and extraction agent, and the water outlet of tower still gets into biochemical treatment workshop section;

The top side line is extracted gas phase out after cooling, oily water separation, and extraction agent recycles, and phlegma gets into waste water tank or the sour water stripping (SWS) tower carries out the dephenolize deamination, and the solvent behind the dephenolize deamination is recycled recovery; The bottom side line obtains ammonia and sends into the ammonia refining system after three grades of fractional condensation; One-level partial condenser working pressure is 0.3 ~ 0.5MPa; Service temperature is 110 ~ 140 ℃, and the working pressure of secondary partial condenser is 0.28 ~ 0.4MPa, and service temperature is 70 ~ 105 ℃; The working pressure of three grades of partial condensers is 0.2 ~ 0.35MPa, and service temperature is 30 ~ 50 ℃;

(4) solvent recuperation

The extraction phase that step (2) is obtained gets into phenol tower rectifying separation extraction agent and crude phenols, and the tower still temperature of rectifying phenol tower is 190 ~ 220 ℃, and working pressure is 0.1 ~ 0.2MPa, reflux ratio 0.2 ~ 0.8, and the extraction agent recycle after the separation, crude phenols are as sub product.

2. recovery and treatment method according to claim 1; It is characterized in that in the step (1), the sour gas that uses in the said acid gas absorption tower is as producing in the wastewater treatment process; Only when the initial unlatching of device, need extra introducing; Device move successfully back sour gas circulating inside, and concrete recycle circuit is: the part entering acid gas absorption tower of the sour gas that is produced by the sour water stripping (SWS) column overhead, rest part entering boiler or emission-control equipment.

3. recovery and treatment method according to claim 2 is characterized in that, in the step (1), said sour gas is carbonic acid gas and/or hydrogen sulfide.

4. recovery and treatment method according to claim 3 is characterized in that, in the step (2), said extraction agent is DIPE, hexone or TAME.

5. recovery and treatment method according to claim 4 is characterized in that, in the step (3), adds sodium hydroxide solution or sodium carbonate solution when said side line adds alkali, and the mass concentration of said sodium hydroxide solution or sodium carbonate solution is 15 ~ 50%.

6. according to the described recovery and treatment method of one of claim 1 ~ 5; It is characterized in that in the step (3), the sour water stripping (SWS) column overhead is discharged in the gas phase and contained sour gas, water vapour, ammonia and extraction agent; Through cooling, oily water separation; The oil phase extraction agent recycles, and the part circulation of sour gas gets into acid gas absorption tower, and rest part gets into boiler or emission-control equipment.

7. recovery and treatment method according to claim 6; It is characterized in that; In the step (3), sour water stripping (SWS) tower top side line is extracted out in the gas phase and is mainly contained sour gas, water vapour, ammonia and extraction agent, after overcooling, oily water separation; The recycle of oil phase extraction agent, phlegma gets into waste water tank or circulation receipt tower.

8. recovery and treatment method according to claim 7; It is characterized in that; In the step (3), sour water stripping (SWS) tower bottom side line is extracted out in the gas phase and is mainly contained sour gas, water vapour, ammonia and extraction agent, after three grades of fractional condensation; It is refining that the vapor phase ammonia pneumatic transmission is gone into ammonia, and phlegma gets into waste water tank or circulation receipt tower.

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