Device and method for cooperative production of low-temperature water heat energy recovery and desorption device cooling

Abstract

The invention relates to the technical field of urea production equipment, in particular to a device and method for cooperative production of low-temperature water heat energy recovery and desorption device cooling, and the device comprises a low-temperature water system, a lithium bromide refrigeration system and a desorption backflow cooling system, and the low-temperature water system comprises a low-pressure methylamine condenser and a low-temperature water cooler; the lithium bromide refrigerating system comprises a lithium bromide unit and a cold water pump, and the desorption reflux cooling system comprises a reflux condenser, a reflux cold liquid level tank, a desorption tower, a desorption tower heat exchanger and a wastewater cooler. By the adoption of the device and method for cooperative production of heat energy recovery of the low-temperature water and cooling of the analysis device, efficient recovery and utilization of heat of the low-temperature water are achieved, the use amount of circulating water is reduced, the stability of an analysis system is improved, and the problem that a heat exchange pipe is prone to scaling and corrosion is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of urea production equipment, and particularly to a device and method for collaborative production of low-pressure water heat energy recovery and desorption device cooling. Background Art

[0002] In the process of urea production, the low-pressure carbamate condenser (low carbamate cooler) is a core device responsible for condensing the ammonia and carbon dioxide gas mixture discharged from the rectification column. Its supporting low-pressure water system undertakes the function of heat removal. In the traditional process, the temperature of the low-pressure water rises to 60 - 80°C after absorbing the condensation heat, but this part of the low-grade heat energy is not effectively utilized and is usually directly cooled by a circulating water cooler, resulting in a large amount of heat waste and a large consumption of circulating water.

[0003] At the same time, the reflux condenser of the desorption device generally uses circulating water as the cooling medium. Since the gas discharged from the desorption column contains corrosive components such as ammonia and carbamate, when the circulating water exchanges heat with the high-temperature gas phase, it is easy to cause fouling and blockage of the heat exchange tubes due to a large temperature difference, resulting in uneven flow of the circulating water and exacerbating the corrosion of the heat exchange tubes. And when the heat exchange tubes of the reflux cooler leak, ammonia nitrogen will directly pollute the circulating water system, causing a sudden increase in the ammonia nitrogen concentration of the whole plant's circulating water, resulting in the exceeding of the circulating water quality standard, and forced shutdown for maintenance and water replacement is required. During the shutdown maintenance process, urea production needs to be reduced to the minimum amount, seriously affecting urea production and consumption. Summary of the Invention

[0004] The purpose of the present invention is to provide a device and method for collaborative production of low-pressure water heat energy recovery and desorption device cooling, to achieve efficient recovery and utilization of low-pressure water heat, reduce the amount of circulating water used, improve the stability of the desorption system, and solve the problem of easy fouling and corrosion of heat exchange tubes.

[0005] To achieve the above purpose, the present invention provides a device for collaborative production of low-pressure water heat energy recovery and desorption device cooling, including a low-pressure water system, a lithium bromide refrigeration system, and a desorption reflux cooling system. The low-pressure water system includes a low-pressure carbamate condenser and a low-pressure water cooler. The lithium bromide refrigeration system includes a lithium bromide unit and a chilled water pump. The desorption reflux cooling system includes a reflux condenser, a reflux cooling liquid level tank, a desorption column, a desorption column heat exchanger, and a waste water cooler;

[0006] The low-pressure water outlet pipe of the low-pressure carbamate condenser is connected to the low-pressure water inlet pipe of the lithium bromide unit. The low-pressure water outlet pipe of the lithium bromide unit is connected to the low-pressure water circulation pump. The low-pressure water circulation pump is connected to the low-pressure water cooler. The low-pressure water cooler is connected to the low-pressure water inlet pipe of the low-pressure carbamate condenser;

[0007] The chilled water outlet pipe one of the lithium bromide unit is connected to the chilled water pump. The chilled water pump is connected to the chilled water inlet pipe two of the reflux condenser. The chilled water outlet pipe two of the reflux condenser is connected to the chilled water inlet pipe one of the lithium bromide unit;

[0008] The reflux condenser is also connected to a reflux cold liquid level tank. The liquid phase pipeline of the reflux cold liquid level tank is connected to the stripping column through a reflux pump. The waste liquid pipe at the bottom of the stripping column is connected to the waste liquid inlet 1 of the stripping column heat exchanger, and the waste liquid outlet 1 of the stripping column heat exchanger is connected to the waste liquid inlet 2 of the waste water cooler.

[0009] Preferably, the low-pressure aqua ammonia condenser's low-temperature water outlet pipe is also connected to a low-temperature water circulation pump through a low-temperature water regulating valve.

[0010] Preferably, a temperature regulating valve is installed on the main line of the low-temperature water cooler, a flow regulating valve is installed on the secondary line of the low-temperature water cooler, and a circulating water regulating valve is installed on the inlet circulating water pipeline of the low-temperature water cooler.

[0011] Preferably, the cold water pump is also connected to the cold water inlet of the waste water cooler, and the cold water outlet of the waste water cooler is connected to the cold water inlet pipe 1 of the lithium bromide unit.

[0012] Preferably, the gas phase pipeline of the reflux cold liquid level tank is connected to the atmospheric absorption column, and the reflux pump is also connected to the gas phase pipeline of the rectifying column at the bottom of the low-pressure aqua ammonia condenser.

[0013] Preferably, the gas outlet pipeline and the ammonia water pipeline at the top of the stripping column are both connected to the bottom inlet of the reflux condenser. The ammonia water pipeline is also connected to the ammonia water inlet of the stripping column heat exchanger, and the ammonia water outlet of the stripping column heat exchanger is connected to the stripping column.

[0014] Preferably, a low-temperature water high-level tank is connected to the low-temperature water outlet pipe of the low-pressure aqua ammonia condenser, a reflux cold high-level tank is connected to the water outlet pipe of the reflux condenser, and the waste liquid outlet 2 of the waste water cooler is connected to the low-temperature water high-level tank and the reflux cold high-level tank respectively through a stripping waste liquid pump.

[0015] Preferably, a cut-off valve is installed on the bottom pipeline of the reflux cold high-level tank.

[0016] The present invention also provides a production method for the above-mentioned device for collaborative production of low-temperature water heat energy recovery and stripping device cooling, including the following steps:

[0017] S1. Heat recovery of the low-temperature water system

[0018] S1.1. The high-temperature low-temperature water generated by the low-pressure aqua ammonia condenser enters the lithium bromide unit for heat exchange, transferring the heat to the lithium bromide solution, causing the water in the lithium bromide solution to evaporate into refrigerant vapor for preparing cold water;

[0019] S1.2. The low-temperature water coming out of the lithium bromide unit enters the low-temperature water heat exchanger through the low-temperature water circulation pump for further cooling, and the cooled low-temperature water re-enters the low-pressure aqua ammonia condenser for recycling;

[0020] S2. Lithium bromide refrigeration system

[0021] The chilled water of the lithium bromide unit is divided into two paths by the chilled water pump. One path is sent back to the reflux condenser, and the other path is sent to the waste water cooler. The chilled water coming out of the reflux condenser then returns to the lithium bromide unit to form a chilled water cycle.

[0022] S3. Analytical reflux cooling system

[0023] S3.1. The outgas of the analytical column and ammonia water enter the reflux condenser from the bottom inlet of the reflux condenser, are cooled and then discharged from the top of the reflux condenser to the reflux cooling liquid level tank. The gas phase of the reflux cooling liquid level tank goes to the atmospheric absorption column; the liquid phase reflux liquid of the reflux cooling liquid level tank is sent to the top of the analytical column and the gas phase pipeline of the rectification column respectively by the reflux pump.

[0024] S3.2. The waste liquid at the bottom of the analytical column is first cooled by the analytical column heat exchanger and then enters the waste water cooler for further cooling. A part of the cooled analytical waste liquid is sent out by the analytical waste liquid pump, and part of the analytical waste liquid is led to the low-profile water high-level tank and the reflux cooling high-level tank as makeup water.

[0025] Advantages of the present invention:

[0026] (1) The present invention adopts a device and method for collaborative production of low-profile water heat energy recovery and analytical cooling with the above structure. The low-grade heat energy of the low-profile water is used to produce chilled water by the lithium bromide unit, avoiding the waste of heat directly discharged into the circulating water, and at the same time reducing the consumption of by-product steam of urea by the lithium bromide unit, realizing the cascade utilization of energy and reducing energy consumption.

[0027] (2) The present invention adopts a device and method for collaborative production of low-profile water heat energy recovery and analytical cooling with the above structure. The amount of circulating water used in the low-profile water cooler is reduced because the low-profile water is first cooled by the lithium bromide unit; the lithium bromide unit uses demineralized water instead of circulating water as chilled water, and the reflux condenser and the waste water cooler use analytical waste liquid as makeup water, all of which reduce the amount of circulating water used and save water resources.

[0028] (3) The present invention adopts a device and method for collaborative production of low-profile water heat energy recovery and analytical cooling with the above structure. The reflux condenser uses the chilled water of the lithium bromide unit and the analytical waste liquid instead of the circulating water used in the whole plant circulation as the cooling medium. When the heat exchange tube leaks, the ammonia nitrogen leaking into the chilled water is limited within the closed-loop system of reflux condenser → lithium bromide unit → chilled water pump, and does not contact the circulating water and demineralized water total system, avoiding polluting the circulating water of the whole plant.

[0029] (4) The device and method for collaborative production of low-key water heat energy recovery and analysis with cooling of the present invention adopt the above-mentioned structure. The reflux condenser and the waste water cooler use the analyzed waste liquid (basically steam condensate) as the cooling medium, and its water quality is relatively clean, effectively solving the problems that circulating water is prone to scale formation, blockage of heat exchange tubes and aggravated corrosion due to large temperature difference, prolonging the service life of the equipment and reducing the equipment maintenance frequency.

[0030] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0031] Figure 1 is a schematic diagram of the device for collaborative production of low-key water heat energy recovery and analysis with cooling of the present invention;

[0032] Figure 2 is a partial schematic diagram of the analysis reflux cooling system of the present invention.

[0033] Reference Signs:

[0034] 1. Low-key water system; 11. Low-pressure carbamate condenser; 111. Low-key water outlet pipe; 112. Low-key water inlet pipe; 12. Low-key water cooler; 13. Rectifying tower gas phase pipeline; 14. Low-key water circulation pump; 15. Low-key water regulating valve; 16. Temperature regulating valve; 17. Flow regulating valve; 18. Circulating water regulating valve; 19. Low-key water high-level tank;

[0035] 2. Lithium bromide refrigeration system; 21. Lithium bromide unit; 22. Chilled water pump; 23. Low-key water inlet pipe; 24. Low-key water outlet pipe; 25. Chilled water outlet pipe 1; 26. Chilled water inlet pipe 1;

[0036] 3. Analysis reflux cooling system; 31. Reflux condenser; 311. Chilled water outlet pipe 2; 312. Chilled water inlet pipe 2; 32. Reflux cooling liquid level tank; 321. Liquid phase pipeline; 33. Analysis tower; 331. Waste liquid pipe; 332. Gas outlet pipeline; 34. Analysis tower heat exchanger; 341. Waste liquid inlet 1; 342. Waste liquid outlet 1; 343. Ammonia water inlet; 344. Ammonia water outlet; 35. Waste water cooler; 351. Waste liquid inlet 2; 352. Waste liquid outlet 2; 353. Chilled water inlet; 354. Chilled water outlet; 36. Reflux pump; 37. Analyzed waste liquid pump; 38. Reflux cooling high-level tank; 39. Shut-off valve. Detailed Embodiments

[0037] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the field to which the present invention pertains. The above-mentioned features mentioned in the present invention or the features mentioned in the specific examples can be combined arbitrarily. These specific embodiments are only used to illustrate the present invention and do not limit the scope of the present invention.

[0038] Embodiment 1

[0039] As Figures 1 to 2 shown, the present invention provides a device for collaborative production of low-pressure water heat energy recovery and desorption device cooling, including a low-pressure water system 1, a lithium bromide refrigeration system 2, and a desorption reflux cooling system 3. The low-pressure water system 1 includes a low-pressure ammonium carbamate condenser 11 and a low-pressure water cooler 12. The lithium bromide refrigeration system 2 includes a lithium bromide unit 21 and a chilled water pump 22. The desorption reflux cooling system 3 includes a reflux condenser 31, a reflux cooling liquid level tank 32, a desorption tower 33, a desorption tower heat exchanger 34, and a wastewater cooler 35.

[0040] The bottom of the low-pressure ammonium carbamate condenser 11 is connected to the gas-phase pipeline 13 of the rectification tower. The gas phase of the rectification tower enters the low-pressure ammonium carbamate condenser 11 for condensation, and the generated ammonium carbamate solution is discharged from the upper part. The low-pressure water outlet pipe 111 at the top of the low-pressure ammonium carbamate condenser 11 is connected to the low-pressure water inlet pipe 23 of the lithium bromide unit 21. The low-pressure water outlet pipe 24 of the lithium bromide unit 21 is connected to the low-pressure water circulation pump 14. The low-pressure water circulation pump 14 is connected to the low-pressure water cooler 12. The low-pressure water cooler 12 is connected to the low-pressure water inlet pipe 112 at the top of the low-pressure ammonium carbamate condenser 11. After the low-pressure water of the low-pressure ammonium carbamate condenser 11 enters the lithium bromide unit 21 to exchange heat and recover heat, it is then sent to the low-pressure water cooler 12 by the low-pressure water circulation pump 14 for cooling. While realizing the recovery and utilization of the low-pressure water heat energy, it also reduces the use of circulating water in the low-pressure water cooler 12.

[0041] The low-pressure water outlet pipe 111 of the low-pressure ammonium carbamate condenser 11 is also connected to the low-pressure water circulation pump 14 through a low-pressure water regulating valve 15. The low-pressure water regulating valve 15 is used to regulate the flow direction of the low-pressure water. During normal production, the low-pressure water regulating valve 15 is closed, so that the high-temperature low-pressure water discharged from the low-pressure ammonium carbamate condenser 11 is all recovered for heat energy by the lithium bromide unit 21. When the lithium bromide unit 21 fails or needs to be overhauled, the low-pressure water regulating valve 15 is opened, and the high-temperature low-pressure water can bypass the lithium bromide unit 21 and directly enter the low-pressure water circulation pump 14, avoiding the paralysis of the entire low-pressure water system 1 due to the shutdown of the lithium bromide unit 21, ensuring the continuity of urea production, and realizing the efficient and stable operation of the low-pressure water system 1 under different working conditions.

[0042] A temperature regulating valve 16 is installed on the main line of the low-key water cooler 12, a flow regulating valve 17 is installed on the secondary line of the low-key water cooler 12, and a circulating water regulating valve 18 is installed on the inlet circulating water pipeline of the low-key water cooler 12. The flow regulating valve 17 cooperates with the temperature regulating valve 16 to regulate the bypass flow of the low-key water cooler 12. When the temperature of the low-key water meets the process requirements after being cooled by the lithium bromide unit 21, the secondary line flow regulating valve 17 can be opened and the temperature regulating valve 16 can be closed slightly to allow some low-key water to directly bypass the cooler, reducing the load of the cooler and the consumption of circulating water. When it is necessary to increase the cooling capacity (such as when the lithium bromide unit 21 fails or the temperature of the low-temperature regulated water is too high), the secondary line flow regulating valve 17 is closed and the temperature regulating valve 16 is opened wide to make all the low-key water pass through the main line of the low-key water cooler 12 to ensure the cooling effect.

[0043] The cold water outlet pipe 25 of the lithium bromide unit 21 is connected to the cold water pump 22, the cold water pump 22 is connected to the cold water inlet pipe 312 of the reflux condenser 31, and the cold water outlet pipe 311 of the reflux condenser 31 is connected to the cold water inlet pipe 26 of the lithium bromide unit 21. The cold water pump 22 is also connected to the cold water inlet 353 of the waste water cooler 35, and the cold water outlet 354 of the waste water cooler 35 is connected to the cold water inlet pipe 26 of the lithium bromide unit 21.

[0044] In addition to using low-key water as a heat source, the lithium bromide unit 21 is also connected with by-product steam of urea as a heat source. The cooling medium of the lithium bromide unit 21 is desalted water from the desalination station to produce cold water. The cold water of the lithium bromide unit 21 is divided into two paths by the cold water pump 22. One path is sent to the reflux condenser 31 to cool the gas from the analysis tower 33 and ammonia water. The cold water coming out of the reflux condenser 31 then returns to the lithium bromide unit 21 to form a cold water cycle. The other path is sent to the waste water cooler 35 to cool the analysis waste liquid produced by the analysis tower 33.

[0045] The gas outlet pipeline 332 at the top of the analysis tower 33 and the ammonia water pipeline are both connected to the bottom inlet of the reflux condenser 31. The reflux condenser 31 is also connected to the reflux cold liquid level tank 32. The gas from the analysis tower 33 and ammonia water enter the lower part of the reflux condenser 31 together, and after being cooled, they are discharged from the top of the reflux condenser 31 and enter the reflux cold liquid level tank 32. The gas phase pipeline of the reflux cold liquid level tank 32 is connected to the atmospheric absorption tower, and the liquid phase pipeline 321 of the reflux cold liquid level tank 32 is connected to the analysis tower 33 through the reflux pump 36. The reflux pump 36 is also connected to the rectifying tower gas phase pipeline 13 at the bottom of the low-pressure methylamine condenser 11.

[0046] The ammonia pipeline is also connected to the ammonia water inlet 343 of the stripping tower heat exchanger 34, and the ammonia water outlet 344 of the stripping tower heat exchanger 34 is connected to the stripping tower 33. After the ammonia pipeline is led out from the external ammonia water storage facility, it is first connected to the ammonia water inlet 343 of the stripping tower heat exchanger 34 and exchanges heat reversely with the high-temperature waste liquid discharged from the bottom of the stripping tower 33. The preheated ammonia water flows out from the ammonia water outlet 344 of the stripping tower heat exchanger 34, and then is sent to the bottom inlet of the reflux condenser 31 to be mixed and cooled with the gas discharged from the stripping tower 33. The waste heat of the stripping waste liquid is used to preheat the ammonia water, reducing the cooling load of the reflux condenser 31 and at the same time reducing the steam consumption of the stripping tower 33.

[0047] The bottom waste liquid pipe 331 of the stripping tower 33 is connected to the waste liquid inlet 1-341 of the stripping tower heat exchanger 34, and the waste liquid outlet 1-342 of the stripping tower heat exchanger 34 is connected to the waste liquid inlet 2-351 of the waste water cooler 35. The high-temperature stripping waste liquid discharged from the bottom of the stripping tower 33 is connected to the waste liquid inlet 1-341 of the stripping tower heat exchanger 34 through the waste liquid pipe 331. After exchanging heat reversely with the ammonia water in the heat exchanger, the stripping waste liquid is discharged from the waste liquid outlet 1-342, and then is connected to the waste liquid inlet 2-351 of the waste water cooler 35 through a pipeline. In the waste water cooler 35, the stripping waste liquid exchanges heat with the low-temperature cold water produced by the lithium bromide unit 21, and after further cooling, it is discharged from the waste liquid outlet 2-352 and sent out of the boundary through the stripping waste liquid pump 37.

[0048] A low-pressure makeup water high-level tank 19 is connected to the low-pressure makeup water outlet pipe 111 of the low-pressure carbamate condenser 11, a reflux cold high-level tank 38 is connected to the water outlet pipe of the reflux condenser 31, and the waste liquid outlet 2-352 of the waste water cooler 35 is connected to the low-pressure makeup water high-level tank 19 and the reflux cold high-level tank 38 respectively through the stripping waste liquid pump 37. The low-pressure makeup water high-level tank 19 and the reflux cold high-level tank 38 use the stripping waste liquid to make up water for the system to maintain the stability of the system liquid level.

[0049] A cut-off valve 39 is installed on the bottom pipeline of the reflux cold high-level tank 38. The cut-off valve 39 remains open during normal operation, and the stripping waste liquid is used to make up water for the reflux cold high-level tank 38 according to the liquid level of the reflux cold high-level tank 38. When the liquid level of the reflux cold high-level tank 38 rises abnormally, the cut-off valve 39 is quickly closed to prevent the liquid in the reflux cold high-level tank 38 from overflowing. The ammonia nitrogen content in the cold water is sampled and analyzed. When the ammonia nitrogen content is high, it can be judged that the internal heat exchange tubes of the reflux cold are leaking, and the ammonia nitrogen leaking into the cold water is limited within the closed-loop system of the reflux condenser 31 → lithium bromide unit 21 → cold water pump 22, and does not come into contact with the total circulating water and desalted water systems, avoiding polluting the circulating water of the whole plant. The stripping and reflux system can maintain normal operation in the short term, and planned shutdown and maintenance are carried out according to the overall production situation and the cold water quality situation.

[0050] Example 2

[0051] The present invention also provides a production method of a device for co-producing cooling in a low-pressure water heat energy recovery and analysis device of Embodiment 1, including the following steps:

[0052] S1. Heat recovery of the low-pressure water system 1

[0053] S1.1. Heat energy recovery under normal conditions. The vapor phase of the rectifying column enters the low-pressure carbamate condenser 11 for condensation. The generated carbamate solution is discharged from the upper part. At the same time, the generated high-temperature low-pressure water flows into the lithium bromide unit 21 from the top outlet pipe of the low-pressure carbamate condenser 11 for heat exchange, transferring the heat to the lithium bromide solution, causing the water in the lithium bromide solution to evaporate into refrigerant vapor for preparing cold water.

[0054] S1.2. The low-pressure water coming out of the lithium bromide unit 21 enters the low-pressure water heat exchanger through the low-pressure water circulation pump 14 for further cooling, and the cooled low-pressure water re-enters the low-pressure carbamate condenser 11 for recycling.

[0055] S1.3. When the lithium bromide unit 21 fails or is under maintenance, open the low-pressure water regulating valve 15, and the high-temperature low-pressure water bypasses the lithium bromide unit 21 and directly enters the low-pressure water cooler 12 through the low-pressure water circulation pump 14 for cooling, maintaining the cooling function of the low-pressure carbamate condenser 11 and avoiding the interruption of urea production.

[0056] S1.4. If the temperature of the low-pressure water already meets the process requirements after passing through the lithium bromide unit 21, open the flow regulating valve 17 on the bypass line of the low-pressure water cooler 12 and close the temperature regulating valve 16 on the main line to bypass part of the low-pressure water around the cooler and reduce the consumption of circulating water; if the lithium bromide unit 21 fails or the temperature of the low-pressure water is too high, close the bypass flow regulating valve 17 and fully open the main line temperature regulating valve 16 to make all the low-pressure water pass through the cooler to ensure the cooling effect.

[0057] S2. Lithium bromide refrigeration system 2

[0058] S2.1. The lithium bromide unit 21 uses low-pressure water (main heat source) and urea by-product steam (auxiliary heat source) as heat drives and desalted water as the cooling medium to produce low-temperature cold water.

[0059] S2.2. The cold water of the lithium bromide unit 21 is divided into two paths by the cold water pump 22. One path is sent back to the reflux condenser 31 to cool the gas discharged from the analysis tower 33 (including ammonia, water vapor, etc.) and ammonia water. The cold water coming out of the reflux condenser 31 then returns to the lithium bromide unit 21 to form a cold water circulation; the other path is sent to the waste water cooler 35 to cool the high-temperature waste liquid discharged from the analysis tower 33, and after heating up, it returns to the lithium bromide unit 21 to form a double-loop cooling circulation.

[0060] S3. Analysis reflux cooling system 3

[0061] S3.1. The gas discharged from the top of the stripping column 33 (containing ammonia and water vapor) converges with the aqueous ammonia from the ammonia pipeline (from an external storage facility), enters the bottom of the reflux condenser 31, and is discharged from the top of the reflux condenser 31 to the reflux cold liquid level tank 32 after cooling.

[0062] The gas phase of the reflux cold liquid level tank 32 goes to the atmospheric absorption tower to recover ammonia in the uncondensed gas and reduce unorganized emissions; the liquid phase reflux liquid of the reflux cold liquid level tank 32 is sent to the top of the stripping column 33 and the gas pipeline 13 of the rectification column (to assist in adjusting the methylammonium liquid balance) through the reflux pump 36 respectively.

[0063] S3.2. The aqueous ammonia is countercurrently heat-exchanged with the high-temperature waste liquid discharged from the bottom of the stripping column 33 through the stripping column heat exchanger 34, and then enters the stripping column 33 after being preheated by the waste heat of the waste liquid, reducing the steam consumption of the stripping column 33.

[0064] The waste liquid at the bottom of the stripping column 33 is first cooled by the stripping column heat exchanger 34, and then enters the waste water cooler 35 for further cooling. A part of the cooled stripping waste liquid is sent out through the stripping waste liquid pump 37, and part of the stripping waste liquid is led to the low-pressure water high-level tank 19 and the reflux cold high-level tank 38 as makeup water.

[0065] S4. Leakage monitoring and control

[0066] The cut-off valve 39 at the bottom of the reflux cold high-level tank 38 is normally open and makes up water as needed; if the liquid level rises abnormally, quickly close the valve to prevent overflow. Regularly take samples to analyze the ammonia nitrogen content of the cold water in the reflux cold high-level tank 38. If the content increases, it is judged that the heat exchange tubes of the reflux condenser 31 are leaking. Since the cold water system is a closed loop (reflux condenser 31 → lithium bromide unit 21 → cold water pump 22), the leaked ammonia nitrogen is restricted within the closed loop, and production can be maintained in the short term. Wait for maintenance during planned shutdown to avoid polluting the whole plant's circulating water system.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions of the present invention or make equivalent replacements, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An apparatus for collaborative production of low-profile water heat energy recovery and analysis device cooling, comprising a low-profile water system, a lithium bromide refrigeration system, and an analysis reflux cooling system, characterized in that: The low-pressure aqua system includes a low-pressure carbamate condenser and a low-pressure aqua cooler. The lithium bromide refrigeration system includes a lithium bromide unit and a chilled water pump. The stripping reflux cooling system includes a reflux condenser, a reflux cooling liquid level tank, a stripping column, a stripping column heat exchanger, and a waste water cooler. The low-pressure aqua outlet pipe of the low-pressure carbamate condenser is connected to the low-pressure aqua inlet pipe of the lithium bromide unit. The low-pressure aqua outlet pipe of the lithium bromide unit is connected to a low-pressure aqua circulation pump. The low-pressure aqua circulation pump is connected to the low-pressure aqua cooler. The low-pressure aqua cooler is connected to the low-pressure aqua inlet pipe of the low-pressure carbamate condenser. The chilled water outlet pipe 1 of the lithium bromide unit is connected to the chilled water pump. The chilled water pump is connected to the chilled water inlet pipe 2 of the reflux condenser. The chilled water outlet pipe 2 of the reflux condenser is connected to the chilled water inlet pipe 1 of the lithium bromide unit. The reflux condenser is also connected to the reflux cooling liquid level tank. The liquid phase pipeline of the reflux cooling liquid level tank is connected to the stripping column through a reflux pump. The waste liquid pipe at the bottom of the stripping column is connected to the waste liquid inlet 1 of the stripping column heat exchanger. The waste liquid outlet 1 of the stripping column heat exchanger is connected to the waste liquid inlet 2 of the waste water cooler.

2. The device for co-producing cooling of a low-key water heat energy recovery and analysis device according to claim 1, characterized in that: The low-pressure aqua outlet pipe of the low-pressure carbamate condenser is also connected to the low-pressure aqua circulation pump through a low-pressure aqua regulating valve.

3. The device for collaborative production of low-key water heat energy recovery and analysis and cooling according to claim 1, wherein: A temperature regulating valve is installed on the main line of the low-pressure aqua cooler. A flow regulating valve is installed on the secondary line of the low-pressure aqua cooler. A circulating water regulating valve is installed on the inlet circulating water pipeline of the low-pressure aqua cooler.

4. A device for collaborative production of cooling in a low-key water heat energy recovery and analysis device according to claim 1, characterized in that: The chilled water pump is also connected to the chilled water inlet of the waste water cooler. The chilled water outlet of the waste water cooler is connected to the chilled water inlet pipe 1 of the lithium bromide unit.

5. The device for co-producing cooling of a low-key water heat energy recovery and analysis device according to claim 1, characterized in that: The gas phase pipeline of the reflux cooling liquid level tank is connected to the atmospheric absorption tower. The reflux pump is also connected to the gas phase pipeline of the rectifying column at the bottom of the low-pressure carbamate condenser.

6. The device for co-producing cooling in a low-profile water heat energy recovery and analysis device according to claim 1, characterized in that: The gas outlet pipeline and the ammonia water pipeline at the top of the stripping column are both connected to the bottom inlet of the reflux condenser. The ammonia water pipeline is also connected to the ammonia water inlet of the stripping column heat exchanger. The ammonia water outlet of the stripping column heat exchanger is connected to the stripping column.

7. The device for co-producing cooling in a low-profile water heat energy recovery and analysis device according to claim 1, characterized in that: A low-pressure aqua high-level tank is connected to the low-pressure aqua outlet pipe of the low-pressure carbamate condenser. A reflux cooling high-level tank is connected to the outlet pipe of the reflux condenser. The waste liquid outlet 2 of the waste water cooler is connected to the low-pressure aqua high-level tank and the reflux cooling high-level tank respectively through a stripping waste liquid pump.

8. An apparatus for co-producing cooling in a low-profile water heat energy recovery and analysis device according to claim 7, characterized in that: A cut-off valve is installed on the bottom pipeline of the reflux cooling high-level tank.

9. A production method of a device for collaborative production of low-key water heat energy recovery and analysis device cooling as described in any one of claims 1-8, characterized in that, Including the following steps: S1. Heat recovery of the low-pressure aqua system S1.

1. The high-temperature low-pressure aqua generated by the low-pressure carbamate condenser enters the lithium bromide unit for heat exchange, transferring heat to the lithium bromide solution, causing the water in the lithium bromide solution to evaporate into refrigerant vapor for preparing chilled water. S1.

2. The low-pressure aqua coming out of the lithium bromide unit enters the low-pressure aqua heat exchanger through the low-pressure aqua circulation pump for further cooling. The cooled low-pressure aqua re-enters the low-pressure carbamate condenser for recycling. S2. Lithium bromide refrigeration system The chilled water of the lithium bromide unit is divided into two paths by the chilled water pump. One path is sent to the reflux condenser, and the other path is sent to the waste water cooler. The chilled water coming out of the reflux condenser returns to the lithium bromide unit to form a chilled water cycle. S3. Stripping reflux cooling system S3.

1. The gas and ammonia water from the stripping column enter the reflux condenser from the bottom inlet of the reflux condenser, are cooled and discharged from the top of the reflux condenser to the reflux cooling liquid level tank. The gas phase of the reflux cooling liquid level tank goes to the atmospheric absorption tower. The liquid-phase reflux liquid of the reflux cold liquid level tank is sent to the top of the stripping column and the gas-phase pipeline of the rectification column respectively by the reflux pump; S3.2 The waste liquid at the bottom of the stripping column is first cooled by the stripping column heat exchanger and then enters the waste water cooler for further cooling. A part of the cooled stripping waste liquid is sent out by the stripping waste liquid pump, and part of the stripping waste liquid is led to the low-profile water high-level tank and the reflux cold high-level tank as makeup water.

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