Salt-containing wastewater evaporation and concentration device taking ammonia distillation waste heat as heat source

Abstract

The utility model belongs to the technical field of ammonia distillation waste heat recycling devices, and particularly relates to a salt-containing wastewater evaporation and concentration device taking ammonia distillation waste heat as a heat source. Comprising an ammonia distillation tower, an evaporative condenser and a salt-containing wastewater pipeline, wherein the evaporative condenser is provided with an ammonia gas inlet, a concentrated ammonia water outlet, an ammonia distillation wastewater inlet, an ammonia distillation wastewater outlet, a low-concentration water inlet, a first high-concentration water outlet, a low-concentration water outlet, a low-concentration spraying opening, a second high-concentration water outlet and a high-concentration spraying opening; an ammonia dephlegmator is mounted at the top end of the ammonia still, an ammonia gas outlet end of the ammonia dephlegmator is communicated with an ammonia gas inlet through a pipeline, a stronger ammonia water outlet is communicated with a desulfurization pipeline, and a wastewater outlet end of the ammonia still is connected with a wastewater settling tank through a pipeline. According to the device, waste heat of ammonia gas and ammonia distillation wastewater can be fully utilized while the ammonia gas is cooled, salt-containing wastewater is evaporated and concentrated, and the concentration and the temperature of the salt-containing wastewater are improved, so that the energy consumption of a subsequent evaporation salt extraction process is greatly reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of ammonia evaporation waste heat recovery and utilization devices, in particular to a salt-containing wastewater evaporation and concentration device using ammonia evaporation waste heat as a heat source. Background Art

[0002] During the coking production process, the moisture brought in by the coking coal and the combined water generated during the coking process are cooled, separated from the oil and water, and deoiled to become residual ammonia water with a temperature of about 75°C. Since the residual ammonia water contains a large amount of toxic and harmful substances such as ammonia, phenol, sulfide, cyanide, etc., the coking industry usually uses ammonia evaporation to treat it, that is, steam is used to evaporate ammonia and some harmful substances. The ammonia vapor and water vapor at about 104°C are cooled by circulating cooling water and sent to the desulfurization device for desulfurization. The remaining ammonia evaporation wastewater with a temperature of about 108°C is first exchanged with the raw ammonia water for ammonia evaporation, and then cooled to 30-40°C by circulating cooling water and sent to the sewage treatment plant for further biochemical treatment.

[0003] On the one hand: During the ammonia evaporation process, every 1m 3 The remaining ammonia water usually consumes 80-120kg of low-pressure steam, and this part of the heat is eventually taken away by the circulating cooling water, resulting in heat waste. On the other hand, the ammonia wastewater cooler usually adopts a spiral plate heat exchanger or a shell-and-tube heat exchanger. Since the remaining ammonia water contains a small amount of tar, after the ammonia evaporation treatment, the asphaltene remaining in the ammonia evaporation wastewater precipitates and accumulates on the low-temperature heat exchanger surface in large quantities, causing the heat exchanger to be blocked and unable to be cleaned, resulting in the need for regular replacement of the heat exchange equipment and increased equipment investment.

[0004] Brine is a high-salt wastewater formed by membrane concentration, ion exchange regeneration or evaporation of surface water, groundwater or other water sources. It mainly comes from circulating water sewage from cooling towers, reverse osmosis concentrated water and concentrated water from other desalination equipment. If brine is discharged directly into natural water bodies, it will increase the salt content of the water body, destroy the ecological balance of the water body, and even cause the death of aquatic organisms. With increasingly stringent environmental protection requirements and the improvement of national emission standards, zero discharge of brine has become an important issue for chemical companies, especially in the relatively water-scarce northern region. The total salt content of clean sewage such as industrial circulating water sewage and RO concentrated water is relatively high, prompting some companies to extract salt from clean sewage. At present, the commonly used salt extraction methods are divided into two types: membrane concentration and evaporation concentration.

[0005] Membrane concentration and evaporation for salt extraction: After collecting saline wastewater such as industrial circulating water, RO concentrated water, etc., sodium carbonate and calcium hydroxide / sodium hydroxide are added to remove calcium and magnesium ions in the wastewater. The clean water after filtration enters the ultrafiltration membrane for filtration, and the filtered clean water enters the primary reverse osmosis membrane (RO membrane) for treatment. The produced clean water with low salt content is reused, and the concentrated water enters the secondary RO membrane and the tertiary RO membrane in turn for concentration. After the brine concentration is concentrated to 4%-8%, it is sent to the evaporation salt extraction device for salt extraction treatment to produce solid salt.

[0006] Disadvantages of membrane concentration and evaporation salt extraction:

[0007] (1) Industrial circulating water and RO concentrated water usually contain high levels of alkali metal ions such as calcium and magnesium. After multi-stage concentration, these alkali metal ions will precipitate in the form of solid salts such as calcium sulfate and calcium carbonate, causing blockage of membrane pores and greatly shortening the service life of the equipment. The double alkali method can remove some alkali metal ions, but it will consume a large amount of raw materials such as sodium carbonate, greatly increasing the operating costs of the device;

[0008] (2) The influent brine concentration of the three-stage RO membrane filtration in the existing device reaches 10,000-20,000 mg / L. The operating pressure of the membrane is relatively high, and the quality requirements of the membrane are relatively high. The operating efficiency of the membrane decays rapidly and the service life is short.

[0009] Evaporation concentration and salt extraction: After collecting saline wastewater such as industrial circulating water, RO concentrated water, etc., sodium carbonate and calcium hydroxide / sodium hydroxide are added to remove calcium and magnesium ions in the wastewater. The clean water after filtration enters the ultrafiltration membrane for filtration, and the filtered clean water enters the primary reverse osmosis membrane (RO membrane) for treatment. The produced low-salt clean water is reused, and the concentrated water enters the secondary RO membrane and the tertiary RO membrane in turn for concentration. After the brine concentration is concentrated to 4%-8%, it is sent to the evaporation salt extraction device for salt extraction treatment to produce solid salt.

[0010] Disadvantages of evaporation and concentration of salt:

[0011] (1) Evaporation and concentration require a large amount of heat, which is usually provided by steam or gas, resulting in high operating costs;

[0012] (2) During the evaporation and concentration process, a large amount of salt-containing wastewater is carried away by the cooling air flow, which can easily cause salt diffusion and pollution. Summary of the invention

[0013] The utility model aims to provide a saline wastewater evaporation and concentration device using the waste heat of ammonia evaporation as a heat source, so as to solve the problems existing in the prior art.

[0014] The utility model solves the technical problem by adopting the following technical scheme: a salt-containing wastewater evaporation and concentration device using the waste heat of ammonia evaporation as a heat source, comprising an ammonia evaporation tower, an evaporative condenser, and a salt-containing wastewater pipeline; the evaporative condenser is provided with an ammonia gas inlet, a concentrated ammonia water outlet, an ammonia evaporation wastewater inlet, an ammonia evaporation wastewater outlet, a low-concentration water inlet, a first high-concentration water outlet, a low-concentration water outlet, a low-concentration spray outlet, a second high-concentration water outlet, and a high-concentration spray outlet;

[0015] An ammonia decompressor is installed at the top of the ammonia still tower. The ammonia outlet of the ammonia decompressor is connected to the ammonia inlet through a pipeline, and the concentrated ammonia outlet is connected to the desulfurization pipeline. The wastewater outlet of the ammonia still tower is connected to the wastewater sedimentation tank through a pipeline. The wastewater sedimentation tank is connected to the ammonia heat exchanger through a pipeline and a wastewater pump. The ammonia heat exchanger is connected to the ammonia still wastewater inlet through a pipeline, and the ammonia still wastewater outlet is connected to the wastewater treatment pipeline.

[0016] The saline wastewater pipeline is connected to the low-concentration water inlet, and the first high-concentration water outlet is connected to the evaporation salt extraction pipeline;

[0017] The low-concentration water outlet is connected to the low-concentration spray port through a pipeline and a low-concentration circulation pump, the second high-concentration water outlet is connected to the cooling water inlet end of the ammonia fractionator through a pipeline and a high-concentration circulation pump, and the cooling water outlet end of the ammonia fractionator is connected to the high-concentration spray port through a pipeline.

[0018] Furthermore, a partition is provided in the middle of the evaporative condenser, which divides the evaporative condenser into two parts: a high-concentration zone and a low-concentration zone. A connecting hole is provided in the middle and lower part of the partition to connect the cooling air and the salt-containing wastewater to the high-concentration zone and the low-concentration zone through the connecting hole.

[0019] Furthermore, the tops of the high-concentration zone and the low-concentration zone of the evaporative condenser are open, and the high-concentration zone and the low-concentration zone of the evaporative condenser are both installed with spray devices and heat exchange pipes from top to bottom.

[0020] Furthermore, the feed end of the spray device in the high-concentration zone is a high-concentration spray port, and the feed end of the spray device in the low-concentration zone is a low-concentration spray port.

[0021] Furthermore, the heat exchanger row pipe is composed of a plurality of straight tubes and a plurality of heat exchanger tube boxes. The plurality of straight tubes are parallel to each other and linearly arranged to form a group of tube rows. The plurality of heat exchanger tube boxes are linearly arranged from top to bottom on both sides of the condensing heat exchanger. The plurality of tube rows are arranged in a zigzag shape and are connected to the heat exchanger tube boxes on both sides of the condensing heat exchanger in sequence from top to bottom, thereby forming a zigzag one-way passage. The first heat exchanger tube box at the upper end of the one-way passage is the head end of the heat exchanger row pipe, and the last heat exchanger tube box at the lower end of the one-way passage is the end of the heat exchanger row pipe. One side of the heat exchanger tube box is open, and a removable box cover is provided at the open end of the heat exchanger tube box.

[0022] Furthermore, the box cover of the heat exchange tube box at the head end of the heat exchange tube in the high-concentration zone is connected to the ammonia inlet, and the box cover of the heat exchange tube box at the end of the heat exchange tube in the high-concentration zone is connected to the concentrated ammonia water outlet. The first high-concentration water outlet is located at the lower position of the side of the high-concentration zone of the evaporative condenser, and the second high-concentration water outlet is located at the bottom of the high-concentration zone of the evaporative condenser.

[0023] Furthermore, the evaporative condenser is provided with an axial flow fan and a water collector in sequence from top to bottom above the spray device in the low-concentration zone. The box cover of the heat exchange tube box at the head end of the heat exchange tube in the low-concentration zone is connected to the ammonia vapor wastewater outlet, and the box cover of the heat exchange tube box at the end of the heat exchange tube in the low-concentration zone is connected to the ammonia vapor wastewater inlet. The low-concentration water inlet is located at the lower position of the side of the low-concentration zone of the evaporative condenser, and the low-concentration water outlet is located at the bottom of the low-concentration zone of the evaporative condenser. The evaporative condenser is provided with an acid addition port at the lower part of the side of the low-concentration zone.

[0024] Furthermore, the straight tube is a titanium tube or a ceramic tube.

[0025] Furthermore, the evaporative condenser is an evaporative condenser with an inner lining layer on the inner wall, the inner lining layer of the evaporative condenser is a PP board or fiberglass reinforced plastic, and the surface of the inner lining layer of the evaporative condenser is coated with an anti-corrosion paint layer.

[0026] The utility model has the following beneficial effects:

[0027] 1. The utility model can fully utilize the waste heat of ammonia and ammonia wastewater while cooling ammonia gas, evaporate and concentrate the salt-containing wastewater, increase its concentration and temperature, thereby greatly reducing the energy consumption of the evaporation and salt extraction process. 3 Taking the ammonia evaporation device with an annual capacity of 10000 tons / h as an example, it can save about 3.5t / h-4.0t / h of low-pressure saturated steam for evaporation and concentration. The unit price of steam is 120 yuan / t, which can save more than 3.61 million yuan in evaporation energy consumption costs each year.

[0028] 2. The saline wastewater is circulated in the evaporative condenser through the low-concentration circulating pump and the high-concentration circulating pump, and heat is exchanged with the ammonia gas and the ammonia evaporation wastewater in the heat exchange pipe, so that the ammonia gas is condensed into ammonia water, and the saline wastewater is evaporated and concentrated by gradient, and the temperature is increased, so as to achieve the purpose of recycling the waste heat of ammonia evaporation and increasing the concentration of saline wastewater, avoiding the loss of water resources caused by the cooling of industrial circulating water, and reducing the evaporation of circulating water by 3.5m 3 / h or more, which plays a role in saving water resources.

[0029] 3 After the cooling air enters the evaporative condenser from the open end of the high-concentration zone, it passes through the high-concentration zone and the low-concentration zone for spray washing in turn, and after the water is collected by the water collector, it is discharged from the evaporative condenser through the axial flow fan from the low-concentration zone, which minimizes the amount of brine and salt content brought out by the cooling air, and greatly reduces the impact of concentrated salt dispersion on the surrounding environment.

[0030] 4. When the asphaltene and other substances remaining in the ammonia wastewater precipitate and accumulate in large quantities in the straight pipe, causing the straight pipe to be blocked, the cover of the heat exchange tube box can be opened to clear the blockage, thereby avoiding the blockage of the straight pipe and affecting production.

[0031] 5. By adding a small amount of acid to the evaporative condenser from the acid addition port to control the pH value of the saline wastewater between 4 and 6, the formation and precipitation of alkali metal substances such as calcium sulfate and magnesium hydroxide can be effectively prevented, so that the brine concentration can be increased to 15 times the original concentration without clogging, thereby greatly reducing the water volume and energy consumption of the subsequent evaporation and salt extraction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the utility model.

[0033] Figure 2 It is a front sectional structural schematic diagram of the evaporative condenser of the utility model.

[0034] Figure 3 It is a side sectional structural schematic diagram of a low-concentration zone of an evaporative condenser of the utility model.

[0035] Figure 4 This utility model Figure 2 Schematic diagram of the cross-sectional structure at AA in the middle.

[0036] Among them: 1. Ammonia still; 2. Ammonia fractionator; 3. Wastewater settling tank; 4. Wastewater pump; 5. Evaporative condenser; 51. High concentration zone; 511. Second high concentration water outlet; 512. High concentration spray port; 513. Ammonia gas inlet; 514. Concentrated ammonia water outlet; 52. Low concentration zone; 521. Low concentration water outlet; 522. Low concentration spray port; 523. Ammonia still wastewater outlet; 524. Ammonia still wastewater inlet; 53. Axial flow fan; 54. Partition; 55. Connecting hole; 56. Low-concentration water inlet; 57. First high-concentration water outlet; 58. Water collector; 59. Acid addition port; 6. Low-concentration circulation pump; 7. High-concentration circulation pump; 8. Ammonia heat exchanger; 9. Heat exchanger pipe; 91. Straight pipe; 92. Heat exchanger pipe box; 93. Box cover; 10. Spraying device; 11. Wastewater treatment pipeline; 12. Salt-containing wastewater pipeline; 13. Evaporation and salt extraction pipeline; 14. Desulfurization pipeline; 15. Pipeline. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0038] like Figure 1-4As shown, a salt-containing wastewater evaporation and concentration device using the waste heat of ammonia evaporation as a heat source includes an ammonia evaporation tower 1, an evaporative condenser 5, and a salt-containing wastewater pipeline 12. The evaporative condenser 5 is provided with an ammonia gas inlet 513, a concentrated ammonia water outlet 514, an ammonia evaporation wastewater inlet 524, an ammonia evaporation wastewater outlet 523, a low-concentration water inlet 56, a first high-concentration water outlet 57, a low-concentration water outlet 521, a low-concentration spray port 522, a second high-concentration water outlet 511, and a high-concentration spray port 512.

[0039] An ammonia fractionator 2 is installed at the top of the ammonia still 1. The ammonia outlet of the ammonia fractionator 2 is connected to the ammonia inlet 513 through a pipeline 15, and the concentrated ammonia outlet 514 is connected to the desulfurization pipeline 14. The wastewater outlet of the ammonia still 1 is connected to the wastewater sedimentation tank 3 through a pipeline 15. The wastewater sedimentation tank 3 is connected to the ammonia heat exchanger 8 through a pipeline 15 and a wastewater pump 4. The ammonia heat exchanger 8 is connected to the ammonia wastewater inlet 524 through a pipeline 15, and the ammonia wastewater outlet 523 is connected to the wastewater treatment pipeline 11.

[0040] The saline wastewater pipeline 12 is connected to the low-concentration water inlet 56 , and the first high-concentration water outlet 57 is connected to the evaporation salt extraction pipeline 13 .

[0041] The low-concentration water outlet 521 is connected to the low-concentration spray port 522 through the pipeline 15 and the low-concentration circulation pump 6, the second high-concentration water outlet 511 is connected to the cooling water inlet end of the ammonia decompressor 2 through the pipeline 15 and the high-concentration circulation pump 7, and the cooling water outlet end of the ammonia decompressor 2 is connected to the high-concentration spray port 512 through the pipeline 15.

[0042] A partition 54 is provided in the middle of the evaporative condenser 5 , which divides the evaporative condenser 5 into two parts: a high-concentration zone 51 and a low-concentration zone 52 . A connecting hole 55 is provided in the lower middle part of the partition 54 , which is used to connect the cooling air and the salt-containing wastewater to the high-concentration zone 51 and the low-concentration zone 52 through the connecting hole 55 .

[0043] The tops of the high-concentration area 51 and the low-concentration area 52 of the evaporative condenser 5 are both open, and a spray device 10 and a heat exchange pipe 9 are installed from top to bottom in the high-concentration area 51 and the low-concentration area 52 of the evaporative condenser 5. The spray device 10 is a common spray method, composed of a plurality of spray pipes, which are connected in parallel to the spray main pipeline, and a nozzle is installed on the spray pipe, so that the cooling medium is sprayed from the nozzle to the heat exchange pipe 9, thereby realizing heat exchange.

[0044] The feed end of the spray device 10 in the high-concentration zone 51 is a high-concentration spray port 512 , and the feed end of the spray device 10 in the low-concentration zone 52 is a low-concentration spray port 522 .

[0045] The heat exchange row pipe 9 is composed of a plurality of straight pipes 91 and a plurality of heat exchange tube boxes 92. The plurality of straight pipes 91 are parallel to each other and are arranged linearly to form a group of tube rows. The plurality of heat exchange tube boxes 92 are arranged linearly from top to bottom on both sides of the condensing heat exchanger. The plurality of groups of tube rows are arranged in a zigzag shape and sequentially connect the heat exchange tube boxes 92 on both sides of the condensing heat exchanger from top to bottom, thereby forming a zigzag one-way passage. That is, the heat exchange tube box 92 at the top of one side of the condensing heat exchanger is connected to the heat exchange tube box 92 at the top of the other side of the condensing heat exchanger through the tube row, and then connected back to the second heat exchange tube box 92 from the top on the opposite side through the tube row, and so on, thereby forming a one-way passage.

[0046] The first heat exchange tube box 92 at the upper end of the one-way passage is the head end of the heat exchange exhaust pipe 9, and the last heat exchange tube box 92 at the lower end of the one-way passage is the end of the heat exchange exhaust pipe 9. One side of the heat exchange tube box 92 is open, and a removable box cover 93 is provided at the open end of the heat exchange tube box 92.

[0047] The box cover 93 of the head end heat exchange tube box 92 of the heat exchange tube 9 in the high concentration zone 51 is connected to the ammonia inlet 513, and the box cover 93 of the tail end heat exchange tube box 92 of the heat exchange tube 9 in the high concentration zone 51 is connected to the concentrated ammonia water outlet 514. The first high concentration water outlet 57 is located at the lower position of the side of the high concentration zone 51 of the evaporative condenser 5, and the second high concentration water outlet 511 is located at the bottom of the high concentration zone 51 of the evaporative condenser 5.

[0048] The evaporative condenser 5 is provided with an axial flow fan 53 and a water collector 58 in order from top to bottom above the spray device 10 in the low concentration zone 52. The box cover 93 of the heat exchange tube box 92 at the head end of the heat exchange tube 9 in the low concentration zone 52 is connected to the ammonia evaporation waste water outlet 523. The box cover 93 of the heat exchange tube box 92 at the end of the heat exchange tube 9 in the low concentration zone 52 is connected to the ammonia evaporation waste water inlet 524. The low concentration water inlet 56 is located at the lower position of the side of the low concentration zone 52 of the evaporative condenser 5. The low concentration water outlet 521 is located at the bottom of the low concentration zone 52 of the evaporative condenser 5. The evaporative condenser 5 is provided with an acid addition port 59 at the lower part of the side of the low concentration zone 52.

[0049] The straight tube 91 is a titanium tube or a ceramic tube.

[0050] The evaporative condenser 5 is an evaporative condenser 5 with an inner lining layer on the inner wall. The inner lining layer of the evaporative condenser 5 is a PP plate or glass fiber reinforced plastic. The surface of the inner lining layer of the evaporative condenser 5 is coated with an anti-corrosion paint layer.

[0051] The working principle of the utility model is:

[0052] The remaining ammonia water enters the ammonia evaporation tower 1 for ammonia evaporation. The evaporated ammonia gas and water vapor are cooled by the ammonia fractionator 2 and enter the heat exchange exhaust pipe 9 of the high concentration zone 51 of the evaporative condenser 5. After heat exchange and cooling, the ammonia gas becomes concentrated ammonia water and flows from the desulfurization pipeline 14 to the next desulfurization process.

[0053] The ammonia evaporation wastewater after ammonia evaporation enters the wastewater sedimentation tank 3 from the bottom of the ammonia evaporation tower 1 for sedimentation. The settled ammonia evaporation wastewater is pumped into the ammonia heat exchanger 8 through the wastewater pump 4 for heat exchange, and then enters the heat exchange exhaust pipe 9 of the low concentration zone 52 of the evaporative condenser 5 for heat exchange and cooling, and finally flows to the wastewater treatment device through the wastewater treatment pipeline 11 for the next step of treatment.

[0054] The salt-containing wastewater continuously enters the low-concentration zone 52 of the evaporative condenser 5 from the salt-containing wastewater pipeline 12, and the low-concentration circulation pump 6 pumps it into the spray device 10 of the low-concentration zone 52. The ammonia vapor wastewater in the heat exchange exhaust pipe 9 is sprayed downward from the spray device 10 to cool down and then returns to the bottom of the low-concentration zone 52, thereby forming a cycle.

[0055] After the cooling air enters the evaporative condenser 5 from the open end of the high-concentration zone 51, it passes through the high-concentration zone 51 and the low-concentration zone 52 for spray washing in turn, and is discharged from the evaporative condenser 5 through the axial flow fan 53 after the water is collected by the water collector 58, thereby minimizing the amount of salt water and the salt content brought out by the cooling air, and greatly reducing the impact of concentrated salt dispersion on the surrounding environment.

[0056] The saline wastewater is evaporated and concentrated in the low-concentration zone 52 to increase the salt concentration, and is temporarily stored at the bottom. When the liquid level is higher than the connecting hole 55, it overflows into the high-concentration zone 51, and is pumped into the ammonia decompressor 2 by the high-concentration circulation pump 7 to cool the evaporated ammonia vapor and water vapor, and flows back to the high-concentration zone 51, thus forming a cycle. When the saline wastewater in the high-concentration zone 51 has a liquid level higher than the height of the first high-concentration water outlet 57, it flows from the first high-concentration water outlet 57 through the evaporation and salt extraction pipeline 13 to the evaporation and salt extraction process for the next step of evaporation and salt extraction.

[0057] Since the saline wastewater is evaporated and concentrated in the evaporative condenser 5, a small amount of acid is added to the evaporative condenser 5 from the acid adding port 59 to control the pH value of the saline wastewater to be between 4 and 6, which can effectively prevent the formation and precipitation of alkali metal substances such as calcium sulfate and magnesium hydroxide, so that the brine concentration can be increased to 15 times the original concentration without clogging, thereby greatly reducing the energy consumption of the subsequent evaporative salt extraction process.

[0058] The heat exchange exhaust pipe 9 is composed of a straight pipe 91 and a heat exchange pipe box 92. When the asphaltene and the like remaining in the ammonia wastewater precipitate and accumulate in large quantities in the straight pipe 91, causing the straight pipe 91 to be blocked, the box cover 93 of the heat exchange pipe box 92 can be opened to clear the blockage.

[0059] It should be noted that Figure 1-Figure 3 This is a schematic diagram of the connection method of each structure of the utility model, which does not show the exact position of the structure. Figure 4 It can be seen that the ammonia evaporation wastewater outlet 523 , the ammonia evaporation wastewater inlet 524 , the ammonia gas inlet 513 , and the concentrated ammonia water outlet 514 are respectively located on both sides of the evaporative condenser 5 , rather than being located on the same side of the evaporative condenser 5 .

[0060] The above-described embodiments are merely descriptions of preferred implementations of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by ordinary persons in the art to the technical solution of the present invention shall fall within the scope of protection of the present invention.

[0061] The technology, shape and structure parts not described in detail in the present invention are all known technologies.

Claims

1. A salt-containing wastewater evaporation and concentration device using the waste heat of ammonia evaporation as a heat source, characterized in that: It includes an ammonia distillation tower, an evaporative condenser, and a salt-containing wastewater pipeline. The evaporative condenser is provided with an ammonia gas inlet, a concentrated ammonia water outlet, an ammonia distillation wastewater inlet, an ammonia distillation wastewater outlet, a low-concentration water inlet, a first high-concentration water outlet, a low-concentration water outlet, a low-concentration spray outlet, a second high-concentration water outlet, and a high-concentration spray outlet; An ammonia decompressor is installed at the top of the ammonia still tower. The ammonia outlet of the ammonia decompressor is connected to the ammonia inlet through a pipeline, and the concentrated ammonia outlet is connected to the desulfurization pipeline. The wastewater outlet of the ammonia still tower is connected to the wastewater sedimentation tank through a pipeline. The wastewater sedimentation tank is connected to the ammonia heat exchanger through a pipeline and a wastewater pump. The ammonia heat exchanger is connected to the ammonia still wastewater inlet through a pipeline, and the ammonia still wastewater outlet is connected to the wastewater treatment pipeline. The saline wastewater pipeline is connected to the low-concentration water inlet, and the first high-concentration water outlet is connected to the evaporation salt extraction pipeline; The low-concentration water outlet is connected to the low-concentration spray port through a pipeline and a low-concentration circulation pump, the second high-concentration water outlet is connected to the cooling water inlet end of the ammonia fractionator through a pipeline and a high-concentration circulation pump, and the cooling water outlet end of the ammonia fractionator is connected to the high-concentration spray port through a pipeline.

2. The device for evaporating and concentrating saline wastewater using waste heat from ammonia evaporation as a heat source according to claim 1, characterized in that: A partition is arranged in the middle of the evaporative condenser, which divides the evaporative condenser into a high-concentration zone and a low-concentration zone. A connecting hole is arranged in the middle and lower part of the partition, which is used to connect the high-concentration zone and the low-concentration zone with the cooling air and the salt-containing wastewater through the connecting hole.

3. The device for evaporating and concentrating saline wastewater using waste heat from ammonia evaporation as a heat source according to claim 2, characterized in that: The tops of the high-concentration zone and the low-concentration zone of the evaporative condenser are both open, and spray devices and heat exchange pipes are installed from top to bottom in the high-concentration zone and the low-concentration zone of the evaporative condenser.

4. The device for evaporating and concentrating saline wastewater using waste heat from ammonia evaporation as a heat source according to claim 3, characterized in that: The feed end of the spray device in the high-concentration zone is a high-concentration spray port, and the feed end of the spray device in the low-concentration zone is a low-concentration spray port.

5. The device for evaporating and concentrating saline wastewater using waste heat from ammonia evaporation as a heat source according to claim 3, characterized in that: The heat exchange row pipe is composed of a plurality of straight pipes and a plurality of heat exchange tube boxes. The plurality of straight pipes are parallel to each other and linearly arranged to form a group of tube rows. The plurality of heat exchange tube boxes are linearly arranged from top to bottom on both sides of the condensing heat exchanger. The plurality of tube rows are arranged in a zigzag shape and sequentially connected to the heat exchange tube boxes on both sides of the condensing heat exchanger from top to bottom, thereby forming a zigzag one-way passage. The first heat exchange tube box at the upper end of the one-way passage is the head end of the heat exchange row pipe, and the last heat exchange tube box at the lower end of the one-way passage is the end of the heat exchange row pipe. One side of the heat exchange tube box is open, and a detachable box cover is provided at the open end of the heat exchange tube box.

6. The device for evaporating and concentrating saline wastewater using waste heat from ammonia evaporation as a heat source according to claim 5, characterized in that: The box cover of the heat exchange tube box at the head end of the heat exchange tube in the high concentration zone is connected to the ammonia inlet, and the box cover of the heat exchange tube box at the end of the heat exchange tube in the high concentration zone is connected to the concentrated ammonia water outlet. The first high concentration water outlet is located at the lower position of the side of the high concentration zone of the evaporative condenser, and the second high concentration water outlet is located at the bottom of the high concentration zone of the evaporative condenser.

7. The device for evaporating and concentrating saline wastewater using waste heat from ammonia evaporation as a heat source according to claim 5, characterized in that: The evaporative condenser is provided with an axial flow fan and a water collector in order from top to bottom above the spray device in the low-concentration zone. The box cover of the heat exchange tube box at the head end of the heat exchange tube in the low-concentration zone is connected to the outlet of the ammonia vapor wastewater. The box cover of the heat exchange tube box at the end of the heat exchange tube in the low-concentration zone is connected to the inlet of the ammonia vapor wastewater. The low-concentration water inlet is located at the lower position of the side of the low-concentration zone of the evaporative condenser. The low-concentration water outlet is located at the bottom of the low-concentration zone of the evaporative condenser. The evaporative condenser is provided with an acid addition port at the lower part of the side of the low-concentration zone.

8. The device for evaporating and concentrating saline wastewater using waste heat from ammonia evaporation as a heat source according to claim 5, characterized in that: The straight tube is a titanium tube or a ceramic tube.

9. The device for evaporating and concentrating saline wastewater using waste heat from ammonia evaporation as a heat source according to claim 1, characterized in that: The evaporative condenser is an evaporative condenser with an inner lining layer on the inner wall. The inner lining layer of the evaporative condenser is a PP plate or glass fiber reinforced plastic. The surface of the inner lining layer of the evaporative condenser is coated with an anti-corrosion paint layer.

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