High-concentration organic wastewater treatment system

Abstract

The high-concentration organic wastewater treatment system comprises a deacidification and deamination unit, an extraction and dephenolization unit and an extraction agent recovery unit which are connected in sequence, pollutants such as ammonia nitrogen, sulfide, oil and phenol in the sewage are effectively removed through treatment such as deacidification and deamination, extraction and dephenolization, extraction agent recovery and the like. And a multi-stage heat exchanger in the deacidification and deamination unit improves the heat efficiency of wastewater treatment and reduces the energy consumption at the same time. Due to the design of a water tower in the extraction agent recovery unit, the extraction agent can be recovered and recycled, the material consumption is reduced, and the sewage treatment cost is reduced. In the extraction and dephenolization unit, a tar circulating pump is additionally arranged at the bottom of a phenol tower, so that the temperature of tower bottoms of the phenol tower is quickly increased and is uniform, and the recovery rate and purity of an extracting agent are improved. By effectively treating the high-concentration organic wastewater, the pollution to the environment is reduced, and the ecological environment is favorably protected. And through recycling of the extraction agent and recovery of carbolic oil, the utilization rate of resources is increased, and the sustainable development requirement is met.

Description

Technical Field

[0001] The utility model belongs to the technical field of coal wastewater treatment, and specifically relates to a high-concentration organic wastewater treatment system. Background Art

[0002] Coal wastewater has a complex composition. The nuclear magnetic resonance chromatogram shows that the wastewater contains dozens of inorganic and organic compounds. Among them, inorganic compounds are mainly large amounts of ammonia nitrogen, sulfide, cyanide, etc. In addition to phenols, organic compounds also include monocyclic and polycyclic aromatic compounds, heterocyclic compounds containing nitrogen, sulfur, and oxygen, etc. Since the wastewater also contains various chromophores and auxochromophores, the chromaticity of blue carbon wastewater is as high as tens of thousands times. Phenols, heterocyclic compounds, and ammonia nitrogen contained in the wastewater will cause great harm to humans, aquatic products, and crops. They must be treated to reduce the pollutant content to a certain standard before they can be used.

[0003] Before biochemical treatment of coal wastewater, ammonia nitrogen, sulfide, oil, phenol, etc. in the coal wastewater must be removed. However, the existing system for removing ammonia nitrogen, sulfide and phenol has low energy utilization rate and high energy level consumption. In order to achieve the goal of energy conservation and emission reduction, it is urgent to improve the system. Summary of the invention

[0004] The technical problem to be solved by the utility model is to overcome the shortcomings of the prior art and provide a high-concentration organic wastewater treatment system with reasonable design, high energy utilization rate and environmental protection.

[0005] The technical solution adopted to solve the above technical problems is: a high-concentration organic wastewater treatment system, wherein a deacidification and deammoniation unit, an extraction and dephenolization unit, and an extraction agent recovery unit are connected in sequence;

[0006] The deacidification and deammonification unit is as follows: the raw sewage pipe is divided into two routes, one of which is connected to the hot material inlet of the deacidification and deammonification tower through a three-stage heat exchange mechanism, and the other is connected to the cold material inlet of the deacidification and deammonification tower;

[0007] The deacidification and deammonification tower is provided with a purified water inlet pipe and a hydrogen sulfide exhaust pipe at the top, an ammonia outlet at the side, and a low-pressure steam inlet pipe and a liquid discharge pipe at the bottom. The liquid discharge pipe at the bottom of the deacidification and deammonification tower is connected to the bottom liquid inlet of the three-stage heat exchange mechanism through a bottom liquid pump, the bottom liquid outlet of the three-stage heat exchange mechanism is connected to the extraction dephenolization unit through a wastewater condensation mechanism, the ammonia outlet of the deacidification and deammonification tower is connected to the ammonia inlet of the three-stage heat exchange mechanism, and the ammonia outlet of the three-stage heat exchange mechanism is connected to the ammonia cooling mechanism;

[0008] The three-stage heat exchange mechanism is used for heat exchange between raw sewage and deacidified and deammonified wastewater and ammonia gas;

[0009] The extractive dephenolization unit comprises: a solvent tank is connected to the inlet of a solvent circulation tank through a first solvent booster pump, an outlet of the solvent circulation tank is connected to the solvent inlet of an extraction tower through a second solvent booster pump, a feed port of the extraction tower is connected to a wastewater condensation mechanism, a discharge port of the extraction tower is connected to the feed port of an extract tank, a wastewater discharge port of the extraction tower is connected to an extractant recovery unit, a discharge port of the extract tank is connected to the feed port of a phenol tower through an extract booster pump and an extract heat exchanger connected in sequence, a solvent discharge port of the phenol tower is connected to the feed port of a phenol tower solvent receiving tank through an extract heat exchanger and a solvent condenser, a discharge port of the phenol tower solvent receiving tank is connected to the inlet of a solvent circulation tank, and a phenol oil discharge port of the phenol tower is connected to a tar storage tank through a tar cooler;

[0010] The extractant recovery unit comprises: a feed inlet of a water tower is connected to a wastewater outlet of an extraction tower through a water tower condenser, a drain outlet of the water tower discharges purified water through a water tower condenser and a purified water condenser, and a solvent outlet of the water tower is connected to an inlet of a solvent circulation tank through a water tower top cooler;

[0011] The deacidification and deammoniation tower, the phenol tower and the water tower are all connected with a reboiler.

[0012] As a preferred technical solution, a tar circulation pump is arranged between the phenol oil discharge outlet of the phenol tower and the tar cooler, the inlet of the tar circulation pump is connected to the phenol oil discharge outlet, and the outlet is divided into two paths, one is connected to the inlet of the tar cooler, and the other is connected to the feed port of the phenol tower reboiler.

[0013] As a preferred technical solution, the three-stage heat exchange mechanism includes a first heat exchanger, a second heat exchanger, and a third heat exchanger connected in sequence; the inlet A of the first heat exchanger is connected to the raw sewage pipe, and the outlet A is connected to the inlet A of the second heat exchanger, the outlet A of the second heat exchanger is connected to the inlet A of the third heat exchanger, and the outlet A of the third heat exchanger is connected to the hot material inlet of the deacidification and deammonification tower; the inlet B of the first heat exchanger is connected to the outlet B of the third heat exchanger, and the outlet is connected to the inlet of the wastewater condensation mechanism, the inlet B of the third heat exchanger is connected to the outlet of the bottom liquid pump, the inlet B of the second heat exchanger is connected to the ammonia exhaust outlet of the deacidification and deammonification tower, and the outlet B is connected to the inlet of the ammonia cooling mechanism.

[0014] As a preferred technical solution, the wastewater condensing mechanism includes a first wastewater condenser and a second wastewater condenser connected in series.

[0015] As a preferred technical solution, the ammonia cooling mechanism includes a first gas tank, a second gas tank, a third gas tank, a first ammonia heat exchanger, a second ammonia heat exchanger, and a liquid ammonia cooler. The air inlet of the first gas tank is connected to the outlet B of the second heat exchanger, and the air outlet is connected to the air inlet of the second gas tank through the first ammonia heat exchanger. The air outlet of the second gas tank is connected to the air inlet of the third gas tank through the second ammonia heat exchanger, and the air outlet of the third gas tank discharges ammonia; the discharge pipes of the first gas tank, the second gas tank, and the third gas tank are connected in parallel to the liquid ammonia cooler.

[0016] As a preferred technical solution, the raw wastewater pipe is connected to an alkali adding device.

[0017] The beneficial effects of the utility model are as follows:

[0018] The utility model improves the thermal efficiency of wastewater treatment by arranging a multi-stage heat exchanger, while reducing energy consumption. The design of the water tower allows the extractant to be recovered and recycled, reducing material consumption and reducing the cost of sewage treatment. By adding a tar circulation pump at the bottom of the phenol tower, it is beneficial to quickly increase the temperature of the phenol tower bottom liquid and make the temperature uniform, thereby improving the recovery rate and purity of the extractant.

[0019] The utility model reduces environmental pollution by effectively treating high-concentration organic wastewater, and is helpful to protect the ecological environment. The utilization rate of resources is improved by recycling the extractant and recovering the phenol oil, and meets the requirements of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the process of the deacidification and deammoniation unit of the utility model.

[0021] Figure 2 It is a schematic diagram of the process of the extraction and dephenolization unit and the extraction agent recovery unit of the utility model.

[0022] Among them, the alkali adding device 1, the first heat exchanger 2, the second heat exchanger 3, the deacidification and deammonification tower 4, the third heat exchanger 5, the first ammonia heat exchanger 6, the second ammonia heat exchanger 7, the third gas storage tank 8, the second gas storage tank 9, the first gas storage tank 10, the liquid ammonia cooler 11, the deammonification tower reboiler 12, the tower bottom liquid pump 13, the wastewater condensation mechanism 14, the first solvent booster pump 15, the solvent tank 16, the solvent circulation tank 17, the extraction tower 18, the extract tank 19, the extract lifting pump 20, the extract heat exchanger 21, the solvent condenser 22, the phenol tower 23, the tar storage tank 24, the tar cooler 25, the tar circulation pump 26, the phenol tower reboiler 27, the water tower top cooler 28, the water tower 29, the water tower condenser 30, the purified water condenser 31, the water tower reboiler 32, the second solvent booster pump 33, and the phenol tower solvent receiving tank 34. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited to the following embodiments.

[0024] exist Figure 1 , 2 In the present embodiment, the high-concentration organic wastewater treatment system is composed of a deacidification and deammoniation unit, an extraction and dephenolization unit, and an extraction agent recovery unit connected in sequence.

[0025] The deacidification and deammonification unit is as follows: an alkali adding device 1 is connected to the raw sewage pipe for adjusting the pH value of the raw sewage. The raw sewage after alkali addition is divided into two paths, one path enters from the hot material inlet of the deacidification and deammonification tower 4 after being heated by the three-stage heat exchange mechanism, and the other path enters from the cold material inlet of the deacidification and deammonification tower 4; a purified water inlet pipe and a hydrogen sulfide exhaust pipe are arranged on the top of the deacidification and deammonification tower 4, an ammonia discharge port is arranged on the side, and a low-pressure steam inlet pipe and a drain pipe are arranged at the bottom. The purified water inlet pipe is used to add purified water into the deacidification and deammonification tower 4. In order to reduce the ammonia content in the acid gas at the top of the tower, the hydrogen sulfide exhaust pipe is used to discharge hydrogen sulfide gas. The drain pipe at the bottom of the deacidification and deammonification tower 4 is connected to the tower bottom liquid inlet of the three-stage heat exchange mechanism through a tower bottom liquid pump 13, and the tower bottom liquid outlet of the three-stage heat exchange mechanism is connected to the extraction dephenolization unit through a wastewater condensation mechanism 14. The ammonia discharge port of the deacidification and deammonification tower 4 is connected to the ammonia inlet of the three-stage heat exchange mechanism, and the ammonia outlet of the three-stage heat exchange mechanism is connected to the ammonia cooling mechanism.

[0026] The three-stage heat exchange mechanism includes a first heat exchanger 2, a second heat exchanger 3, and a third heat exchanger 5 which are connected in sequence; the inlet A of the first heat exchanger 2 is connected to the raw sewage pipe, and the outlet A is connected to the inlet A of the second heat exchanger 3, the outlet A of the second heat exchanger 3 is connected to the inlet A of the third heat exchanger 5, and the outlet A of the third heat exchanger 5 is connected to the hot material inlet of the deacidification and deammonification tower 4; the inlet B of the first heat exchanger 2 is connected to the outlet B of the third heat exchanger 5, and the outlet is connected to the inlet of the wastewater condensation mechanism 14, the inlet B of the third heat exchanger 5 is connected to the outlet of the bottom liquid pump 13, the inlet B of the second heat exchanger is connected to the ammonia discharge outlet of the deacidification and deammonification tower 4, and the outlet B is connected to the inlet of the ammonia cooling mechanism.

[0027] The raw sewage after adding alkali is first heat exchanged with the deamination and deacidification wastewater after heat exchange, and then heat exchanged with ammonia for the second time, and finally heat exchanged with the deamination and deacidification wastewater just discharged from the deacidification and deammonification tower 4 for the third time. After three heat exchanges, the raw sewage after adding alkali is changed from cold material to hot material, which fully utilizes the thermal energy and reduces the heat loss.

[0028] The wastewater condensing mechanism 14 comprises a first wastewater condenser and a second wastewater condenser connected in series, and is used to further cool the deamination and deacidification wastewater to reach the extraction temperature.

[0029] The ammonia cooling mechanism includes a first gas tank 10, a second gas tank 9, a third gas tank 8, a first ammonia heat exchanger 6, a second ammonia heat exchanger 7, and a liquid ammonia cooler 11. The air inlet of the first gas tank 10 is connected to the outlet B of the second heat exchanger 3, and the air outlet is connected to the air inlet of the second gas tank 9 through the first ammonia heat exchanger 6. The air outlet of the second gas tank 9 is connected to the air inlet of the third gas tank 8 through the second ammonia heat exchanger 7, and the air outlet of the third gas tank 8 discharges ammonia; the discharge pipes of the first gas tank 10, the second gas tank 9, and the third gas tank 8 are connected in parallel to the liquid ammonia cooler 11, and the liquid ammonia cooler 11 discharges liquid ammonia.

[0030] The bottom of the deacidification and deammonification tower 4 is connected to a deacidification and deammonification tower reboiler 12 and a low-pressure steam pipe, and the low-pressure steam pipe is used to introduce low-pressure steam into the deacidification and deammonification tower 4 to remove ammonia and sulfur in the raw wastewater through a stripping process.

[0031] The extractive dephenolization unit comprises: a solvent tank 16 is connected to the inlet of a solvent circulation tank 17 through a first solvent booster pump 15, an outlet of the solvent circulation tank 17 is connected to the solvent inlet of an extraction tower 18 through a second solvent booster pump 33, a feed port of the extraction tower 18 is connected to a second wastewater condenser, a discharge port of the extraction tower 18 is connected to the feed port of an extract tank 19, a wastewater discharge port of the extraction tower 18 is connected to an extractant recovery unit, a discharge port of the extract tank 19 is connected to the feed port of a phenol tower 23 through an extract booster pump 20 and an extract heat exchanger 21 connected in sequence, the phenol tower 23 is used to separate the solvent (extractant) from phenol oil, a solvent discharge port of the phenol tower 23 is connected to the feed port of a phenol tower solvent receiving tank 34 through an extract heat exchanger 21 and a solvent condenser 22, a discharge port of the phenol tower solvent receiving tank 34 is communicated with the inlet of the solvent circulation tank 17, and a phenol oil discharge port of the phenol tower 23 is connected to a tar storage tank 24 through a tar cooler 25.

[0032] A phenol tower reboiler 27 is connected to the bottom of the phenol tower 23, and a tar circulation pump 26 is installed between the phenol oil discharge port of the phenol tower 23 and the tar cooler 25. The inlet of the tar circulation pump 26 is connected to the phenol oil discharge port, and the outlet is divided into two paths, one of which is connected to the inlet of the tar cooler 25, and the other is connected to the feed port of the phenol tower reboiler 27. The bottom liquid of the phenol tower 23 is sent to the phenol tower reboiler 27 by the tar circulation pump 26 for reheating and then returns to the tower. When the bottom liquid level is high, part of the bottom liquid at the outlet of the tar circulation pump 26 enters the tar cooler 25, and is sent to the tar storage tank 24 after cooling. The tar circulation pump 26 is used to circulate the bottom liquid of the phenol tower 23, which is beneficial to the rapid heating and uniform temperature of the bottom liquid of the phenol tower 23, and can ensure the stable control of various process parameters and smooth operation of the phenol tower 23, and ultimately improve the recovery rate and purity of the extractant. The recovery rate reaches 99.98%, the purity is greater than 99.5%, and the water content of the phenol oil produced from the phenol tower 23 is less than 0.3%.

[0033] The solvent from the solvent circulation tank 17 and the deamination and deacidification wastewater from the deacidification and deamination tower 4 are extracted in the extraction tower 18, and a phenol oil-containing extraction mixture is obtained at the top of the extraction tower 18, which is collected in the extract tank 19, and then heat-exchanged and heated with the solvent gas discharged from the phenol tower 23 in the extract heat exchanger 21, and then used as the feed of the phenol tower 23. At the same time, the solvent gas discharged from the top of the phenol tower 23 is condensed and then sent to the solvent circulation tank 17 for recycling as the extractant of the extraction tower 18.

[0034] The extractant recovery unit is as follows: the feed port of the water tower 29 is connected to the wastewater outlet of the extraction tower 18 through the water tower condenser 30, the water outlet of the water tower 29 discharges purified water through the water tower condenser 30 and the purified water condenser 31, the solvent outlet of the water tower 29 is connected to the inlet of the solvent circulation tank 17 through the water tower top cooler 28, and the lower part of the water tower 29 is connected with a water tower reboiler 32; the wastewater discharged from the wastewater outlet of the extraction tower 18 is heat exchanged with the purified water discharged from the water tower 29 through the water tower condenser 30, the wastewater discharged from the wastewater outlet of the extraction tower 18 is heated and enters the water tower 29, and then enters the water tower reboiler 32, the wastewater discharged from the extraction tower 18 is converted into an azeotrope, the solvent vapor is discharged through the solvent outlet at the top of the water tower 29 and enters the solvent circulation tank 17 after being condensed by the water tower top cooler 28, the purified water is cooled by the water tower condenser 30, and is discharged after cooling by the purified water condenser 31 again.

Claims

1. A high-concentration organic wastewater treatment system, characterized in that: The deacidification and deammoniation unit, the extraction and dephenolization unit, and the extraction agent recovery unit are connected in sequence; The deacidification and deammonification unit is as follows: the raw sewage pipe is divided into two routes, one of which is connected to the hot material inlet of the deacidification and deammonification tower through a three-stage heat exchange mechanism, and the other is connected to the cold material inlet of the deacidification and deammonification tower; The deacidification and deammonification tower is provided with a purified water inlet pipe and a hydrogen sulfide exhaust pipe at the top, an ammonia outlet at the side, and a low-pressure steam inlet pipe and a liquid discharge pipe at the bottom. The liquid discharge pipe at the bottom of the deacidification and deammonification tower is connected to the bottom liquid inlet of the three-stage heat exchange mechanism through a bottom liquid pump, the bottom liquid outlet of the three-stage heat exchange mechanism is connected to the extraction dephenolization unit through a wastewater condensation mechanism, the ammonia outlet of the deacidification and deammonification tower is connected to the ammonia inlet of the three-stage heat exchange mechanism, and the ammonia outlet of the three-stage heat exchange mechanism is connected to the ammonia cooling mechanism; The three-stage heat exchange mechanism is used for heat exchange between raw sewage and deacidified and deammonified wastewater and ammonia gas; The extractive dephenolization unit comprises: a solvent tank is connected to the inlet of a solvent circulation tank through a first solvent booster pump, an outlet of the solvent circulation tank is connected to the solvent inlet of an extraction tower through a second solvent booster pump, a feed port of the extraction tower is connected to a wastewater condensation mechanism, a discharge port of the extraction tower is connected to the feed port of an extract tank, a wastewater discharge port of the extraction tower is connected to an extractant recovery unit, a discharge port of the extract tank is connected to the feed port of a phenol tower through an extract booster pump and an extract heat exchanger connected in sequence, a solvent discharge port of the phenol tower is connected to the feed port of a phenol tower solvent receiving tank through an extract heat exchanger and a solvent condenser, a discharge port of the phenol tower solvent receiving tank is connected to the inlet of a solvent circulation tank, and a phenol oil discharge port of the phenol tower is connected to a tar storage tank through a tar cooler; The extractant recovery unit comprises: a feed inlet of a water tower is connected to a wastewater outlet of an extraction tower through a water tower condenser, a drain outlet of the water tower discharges purified water through a water tower condenser and a purified water condenser, and a solvent outlet of the water tower is connected to an inlet of a solvent circulation tank through a water tower top cooler; The deacidification and deammoniation tower, the phenol tower and the water tower are all connected with a reboiler.

2. The high-concentration organic wastewater treatment system according to claim 1, characterized in that: A tar circulation pump is arranged between the phenol oil outlet of the phenol tower and the tar cooler. The inlet of the tar circulation pump is connected to the phenol oil outlet, and the outlet is divided into two paths, one is connected to the inlet of the tar cooler, and the other is connected to the feed port of the phenol tower reboiler.

3. The high-concentration organic wastewater treatment system according to claim 1, characterized in that: The three-stage heat exchange mechanism includes a first heat exchanger, a second heat exchanger, and a third heat exchanger which are connected in sequence; the inlet A of the first heat exchanger is connected to the raw material sewage pipe, and the outlet A is connected to the inlet A of the second heat exchanger, the outlet A of the second heat exchanger is connected to the inlet A of the third heat exchanger, and the outlet A of the third heat exchanger is connected to the hot material inlet of the deacidification and deammonification tower; the inlet B of the first heat exchanger is connected to the outlet B of the third heat exchanger, and the outlet is connected to the inlet of the wastewater condensation mechanism, the inlet B of the third heat exchanger is connected to the outlet of the tower bottom liquid pump, the inlet B of the second heat exchanger is connected to the ammonia discharge outlet of the deacidification and deammonification tower, and the outlet B is connected to the inlet of the ammonia cooling mechanism.

4. The high-concentration organic wastewater treatment system according to claim 1 or 3, characterized in that: The wastewater condensing mechanism comprises a first wastewater condenser and a second wastewater condenser connected in series.

5. The high-concentration organic wastewater treatment system according to claim 3 is characterized by: The ammonia cooling mechanism includes a first gas tank, a second gas tank, a third gas tank, a first ammonia heat exchanger, a second ammonia heat exchanger, and a liquid ammonia cooler. The air inlet of the first gas tank is connected to the outlet B of the second heat exchanger, and the air outlet is connected to the air inlet of the second gas tank through the first ammonia heat exchanger. The air outlet of the second gas tank is connected to the air inlet of the third gas tank through the second ammonia heat exchanger, and the air outlet of the third gas tank discharges ammonia. The discharge pipes of the first gas tank, the second gas tank, and the third gas tank are connected in parallel to the liquid ammonia cooler.

6. The high-concentration organic wastewater treatment system according to claim 1, characterized in that: The raw material sewage pipe is connected with an alkali adding device.

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