Liquid air adsorption and regeneration device

Abstract

The utility model provides a kind of liquid air adsorption and regeneration device, comprising: first liquid air adsorber;Second liquid air adsorber is arranged in parallel with first liquid air adsorber;Main adsorption circuit;Independent cooling circuit, independent cooling circuit includes first cooling liquid feed branch pipe, second cooling liquid feed branch pipe, first cooling liquid discharge branch pipe and second cooling liquid discharge branch pipe, first cooling liquid feed branch pipe one end is communicated with liquid air feed main pipe and other end is communicated with first liquid air feed branch pipe, second cooling liquid feed branch pipe one end is communicated with liquid air feed main pipe and other end is communicated with second liquid air feed branch pipe, first cooling liquid discharge branch pipe is connected with first liquid air discharge branch pipe, second cooling liquid discharge branch pipe is connected with second liquid air discharge branch pipe;Valve unit.The utility model completely isolates flash gas, so that it will not impact another adsorber being normal work reversely, solve gas jam problem, ensure the continuous stable operation of entire device.

Description

Technical Field

[0001] This utility model relates to an adsorption and regeneration device, specifically a liquid air adsorption and regeneration device, belonging to the technical field of cryogenic air separation equipment. Background Technology

[0002] Air separation units, as key equipment in modern industry, separate air into high-purity oxygen, nitrogen, and other industrial gases through cryogenic distillation, and are widely used in important fields such as petrochemicals and steel metallurgy. Hazardous impurities (hydrocarbons, N2O, CO2) that are not completely removed during the air pretreatment stage will eventually accumulate in the condenser, which is the core equipment of the distillation process, as the process progresses.

[0003] The raw material for crude krypton-xenon extraction is liquid air obtained through cryogenic distillation. This liquid air contains a large amount of liquid oxygen. Due to the vaporization of liquid oxygen, hazardous impurities may accumulate in high concentrations in certain areas, leading to crystallization and precipitation. With sufficient oxygen to support combustion, this can cause an explosion, posing a serious threat to industrial safety. To address this issue, a liquid air adsorber is typically used to remove hazardous impurities from the liquid air. After the adsorbent in the liquid air adsorber becomes saturated, it needs to be regenerated. After regeneration, the adsorber is at room temperature and needs to be cooled before switching adsorbers. In the cooling process, current technology typically uses one of the liquid air outlet lines to directly introduce cryogenic liquid air at approximately -183°C into the adsorber, which has just undergone regeneration and is at room temperature. Upon entering the room temperature adsorber, the cryogenic liquid air undergoes violent flash evaporation, instantly generating a large amount of gas, causing a rapid increase in internal pressure. Because the gas cannot be discharged quickly, air blockage can form. This pressure can even be transmitted back to the shared liquid-air discharge manifold, thus hindering the discharge of liquid-air from another normally operating adsorber and affecting the continuous and stable operation of the entire unit. Furthermore, the cooling process requires a gentle, low-flow-rate coolant flow, while the main feed line and its valves are typically large-diameter and designed for high-flow-rate adsorption conditions. Using such large valves to control a small flow rate results in an extremely narrow adjustable range and insensitive response, making precise and stable cooling flow control impossible and easily leading to uncontrolled cooling processes. Utility Model Content

[0004] Based on the above background, the purpose of this utility model is to provide a liquid air adsorption and regeneration device, which solves the problem of air blockage caused by flash evaporation during the cooling process of the liquid air adsorber by adding an independent cooling circuit, and achieves precise control of the cooling flow rate.

[0005] To achieve the above-mentioned objectives, this utility model provides the following technical solution:

[0006] A liquid air adsorption and regeneration device, comprising:

[0007] First liquid air adsorber;

[0008] A second liquid air adsorber is arranged in parallel with the first liquid air adsorber;

[0009] The main adsorption circuit includes a liquid air feed main pipe and a liquid air discharge main pipe. The liquid air feed main pipe is connected to the bottom of the first liquid air adsorber and the second liquid air adsorber respectively through a first liquid air feed branch pipe and a second liquid air feed branch pipe. The liquid air discharge main pipe is connected to the top of the first liquid air adsorber and the second liquid air adsorber respectively through a first liquid air discharge branch pipe and a second liquid air discharge branch pipe.

[0010] An independent cooling circuit includes a first coolant inlet branch pipe, a second coolant inlet branch pipe, a first coolant outlet branch pipe, and a second coolant outlet branch pipe. One end of the first coolant inlet branch pipe is connected to the liquid air inlet main pipe, and the other end is connected to the first liquid air inlet branch pipe. One end of the second coolant inlet branch pipe is connected to the liquid air inlet main pipe, and the other end is connected to the second liquid air inlet branch pipe. The first coolant outlet branch pipe is connected to the first liquid air outlet branch pipe, and the second coolant outlet branch pipe is connected to the second liquid air outlet branch pipe.

[0011] The valve unit includes a plurality of valves respectively disposed on the first liquid air discharge branch pipe, the second liquid air discharge branch pipe, the first coolant inlet branch pipe, the second coolant inlet branch pipe, the first coolant discharge branch pipe and the second coolant discharge branch pipe.

[0012] When cooling either the first liquid air adsorber or the second liquid air adsorber, the cooling liquid inlet pipe and the cooling liquid outlet pipe provided for that liquid air adsorber are opened by controlling the valve unit, while the liquid air outlet pipe connected to the main liquid air outlet pipe provided for that liquid air adsorber is closed at the same time. That is, each liquid air adsorber has a dedicated independent cooling circuit. This circuit allows the flash gas generated during cooling to be discharged through the dedicated cooling liquid outlet pipe without passing through the main outlet pipe, thereby completely isolating the adsorber being cooled from the pressure interference of the adsorber that is working.

[0013] Preferably, the liquid air adsorption and regeneration device further includes:

[0014] The regeneration circuit includes a first regeneration gas inlet pipe and a second regeneration gas inlet pipe, which are respectively connected to the first liquid air outlet pipe and the second liquid air outlet pipe, a regeneration gas main inlet pipe, and a first regeneration gas outlet pipe and a second regeneration gas outlet pipe led out from the first liquid air inlet pipe and the second liquid air inlet pipe.

[0015] The regenerated gas used for heating desorption enters from the top of the adsorber and exits from the bottom, which is opposite to the flow direction of the liquid air during adsorption, thus improving the desorption efficiency.

[0016] Preferably, the regeneration circuit further includes a vacuum unit, which includes a vacuum pump. The vacuum pump is connected to the first regeneration gas feed pipe and the second regeneration gas feed pipe through a main vacuum pipe, a first vacuum branch pipe, and a second vacuum branch pipe, respectively.

[0017] Vacuuming during the later stages of heating and regeneration can further reduce the partial pressure of impurities on the adsorbent surface, making desorption more thorough.

[0018] Preferably, the diameter of the first coolant inlet branch pipe is smaller than the diameter of the first liquid air inlet branch pipe, and the diameter of the second coolant inlet branch pipe is smaller than the diameter of the second liquid air inlet branch pipe.

[0019] By using a dedicated coolant inlet pipeline with a small diameter and matching it with a corresponding small-diameter valve, it is possible to accurately and smoothly regulate a small flow rate of coolant within a wide valve opening range.

[0020] Preferably, a first detector is provided on the liquid air feed manifold, and a second detector is provided on the liquid air discharge manifold. The first detector is used to monitor the impurity content in the liquid air before adsorption, and the second detector is used to monitor the impurity content in the liquid air after adsorption.

[0021] Preferably, a first flow meter is provided on the liquid air feed main pipe, and a second flow meter is provided on the regenerated gas feed main pipe.

[0022] Preferably, the first liquid air feed branch pipe, the first liquid air discharge branch pipe, the second liquid air feed branch pipe, and the second liquid air discharge branch pipe are respectively equipped with pressure gauges and thermometers for monitoring fluid parameters.

[0023] Preferably, both the first and second liquid air adsorbers are filled with liquid air adsorbent.

[0024] Preferably, all valves are programmable pneumatic valves.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] This utility model provides a liquid air adsorption and regeneration device, which adds an independent cooling circuit to each adsorber. When low-temperature liquid air enters the room-temperature adsorber and flashes, the large amount of gas generated can be discharged through this dedicated channel. At the same time, the valve on the main discharge pipeline is closed, thereby completely isolating the flash gas and preventing it from back-impacting another adsorber that is working normally, solving the gas blockage problem and ensuring the continuous and stable operation of the entire device.

[0027] The independent cooling circuit of this utility model adopts a first coolant inlet branch pipe and a second coolant inlet branch pipe with a pipe diameter smaller than that of the main feed pipe, and is matched with a corresponding small-diameter valve, so that when adjusting the small flow of liquid air required for cooling, precise and stable automatic control can be achieved within a wide valve opening range. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of a liquid air adsorption and regeneration device according to the present invention;

[0030] In the diagram: 1. First liquid air adsorber; 2. Second liquid air adsorber; 3. Liquid air feed main pipe; 4. First liquid air feed branch pipe; 5. Second liquid air feed branch pipe; 6. First liquid air discharge branch pipe; 7. Second liquid air discharge branch pipe; 8. Liquid air discharge main pipe; 9. First coolant feed branch pipe; 10. Second coolant feed branch pipe; 11. Regeneration gas feed main pipe; 12. First regeneration gas feed branch pipe; 13. Second regeneration gas feed branch pipe; 14. First vacuum branch pipe; 15. Second vacuum branch pipe; 16. Vacuum main pipe; 17. First coolant outlet branch pipe; 18. Second coolant outlet branch pipe; 19. First flow meter; 20. First detector; 21. First thermometer; 22. First pressure gauge; 23. Second thermometer; 24. Second pressure gauge; 25. First differential pressure gauge; 26. Second differential pressure gauge; 27. Third pressure gauge; 28. Fourth pressure gauge; 29. ​​Third thermometer; 30. Fourth thermometer; 31. Fifth thermometer; 32. Second flow meter; 33. Vacuum pump; 34. First 35. Second pneumatic valve; 36. Third pneumatic valve; 37. Fourth pneumatic valve; 38. Fifth pneumatic valve; 39. Sixth pneumatic valve; 40. Seventh pneumatic valve; 41. Eighth pneumatic valve; 42. Ninth pneumatic valve; 43. Tenth pneumatic valve; 44. Eleventh pneumatic valve; 45. Twelfth pneumatic valve; 46. First regenerated gas discharge branch pipe; 47. Second regenerated gas discharge branch pipe; 48. Second detector; 49. Thirteenth pneumatic valve; 50. Fourteenth pneumatic valve. Detailed Implementation

[0031] The technical solution of this utility model will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the implementation of this utility model is not limited to the following embodiments; any modifications and / or alterations made to this utility model will fall within the protection scope of this utility model.

[0032] In this invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used are commercially available or commonly used in the field. Unless otherwise specified, the methods in the following embodiments are conventional methods in the field. Unless otherwise specified, the components or equipment in the following embodiments are general standard parts or components known to those skilled in the art, and their structures and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0033] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following detailed description, many specific details are set forth to facilitate explanation and provide a comprehensive understanding of the embodiments of the present invention. However, one or more embodiments may be practiced by those skilled in the art without these specific details.

[0034] like Figure 1 As shown, an embodiment of this utility model discloses a liquid air adsorption and regeneration device, including two parallel-arranged first liquid air adsorber 1 and second liquid air adsorber 2. This dual-tower design ensures that while one adsorber is regenerating, the other can continue adsorption, thereby achieving continuous operation of the entire device. Both the first liquid air adsorber 1 and the second liquid air adsorber 2 are filled with liquid air adsorbent; in this embodiment, silica gel is preferably used, as it has excellent adsorption capacity and can effectively remove hazardous impurities such as carbon dioxide and nitrous oxide from the liquid air.

[0035] The liquid air adsorption and regeneration device also includes a main adsorption circuit, an independent cooling circuit, and a regeneration circuit connected to the first liquid air adsorber 1 and the second liquid air adsorber 2.

[0036] The main adsorption loop is used for normal liquid air purification. The raw liquid air enters from the main liquid air inlet pipe 3, and then flows through either the first liquid air inlet branch pipe 4 or the second liquid air inlet branch pipe 5, entering from the bottom of the first liquid air adsorber 1 and the second liquid air adsorber 2 respectively. The liquid air flows upward through the adsorbent bed, and after purification, it exits from the top of the adsorber through either the first liquid air outlet branch pipe 6 or the second liquid air outlet branch pipe 7 into the main liquid air outlet pipe 8, which then sends it to the downstream process.

[0037] An independent cooling circuit is used to cool the adsorber after regeneration. This circuit consists of a first coolant inlet pipe 9, a second coolant inlet pipe 10, a first coolant outlet pipe 17, and a second coolant outlet pipe 18. Specifically, one end of the first coolant inlet pipe 9 is connected to the liquid air inlet main pipe 3, and the other end is connected to the first liquid air inlet pipe 4. The first coolant outlet pipe 17 is led out from the first liquid air outlet pipe 6. The cooling circuit (second coolant inlet pipe 10 and second coolant outlet pipe 18) of the second liquid air adsorber has the same structure. In this embodiment, the cooling medium is the raw liquid air from the liquid air inlet main pipe 3.

[0038] The regeneration circuit is used to heat and desorb the saturated adsorbent. In this embodiment, dry nitrogen or air is used as the regeneration gas, which flows through the main regeneration gas inlet 11, through the first regeneration gas inlet branch 12 or the second regeneration gas inlet branch 13, and into the first liquid air outlet branch 6 or the second liquid air outlet branch 7, flowing downwards through the adsorber for heating. The desorbed waste gas is discharged from the bottom of the adsorber through the first regeneration gas outlet branch 46 or the second regeneration gas outlet branch 47.

[0039] To ensure more thorough desorption, a vacuum unit is also connected to the regeneration circuit. This system consists of a vacuum pump 33, a main vacuum pipe 16, a first vacuum branch pipe 14, and a second vacuum branch pipe 15. The first vacuum branch pipe 14 is connected to the first regeneration gas inlet branch pipe 12, and the second vacuum branch pipe 15 is connected to the second regeneration gas inlet branch pipe 13. Both are connected to the main vacuum pipe 16, and the vacuum pump 33 is installed on the main vacuum pipe 16. By using the vacuum unit to evacuate the adsorber during the later stages of regeneration, the regeneration efficiency can be effectively improved, and contamination of the feed liquid air after switching can be prevented.

[0040] To achieve automated control, programmable pneumatic valves are installed on all the aforementioned key pipelines. Specifically, these include: first pneumatic valve 34, second pneumatic valve 35, third pneumatic valve 36, fourth pneumatic valve 37, fifth pneumatic valve 38, sixth pneumatic valve 39, seventh pneumatic valve 40, eighth pneumatic valve 41, ninth pneumatic valve 42, tenth pneumatic valve 43, eleventh pneumatic valve 44, twelfth pneumatic valve 45, thirteenth pneumatic valve 49, and fourteenth pneumatic valve 50.

[0041] The liquid air adsorption and regeneration unit is also equipped with a comprehensive instrumentation system to monitor the process. A first flow meter 19 for monitoring the flow rate of the raw liquid air and a first detector 20 for monitoring the impurity content before adsorption are installed on the liquid air feed main 3. A second detector 48 for monitoring the impurity content after adsorption is installed on the liquid air discharge main 8. A second flow meter 32 and a fifth thermometer 31 for detecting the regeneration gas flow rate are installed on the regeneration gas feed main 11. At the inlet and outlet of the adsorber, a first thermometer 21 and a first pressure gauge 22 are installed on the first liquid air feed branch 4; a third thermometer 29 and a third pressure gauge 27 are installed on the first liquid air discharge branch 6; and a first differential pressure gauge 25 is also installed between the inlet and outlet of the first liquid air adsorber 1. Similarly, a second thermometer 23 and a second pressure gauge 24 are installed on the second liquid air feed branch 5; a fourth thermometer 30 and a fourth pressure gauge 28 are installed on the second liquid air discharge branch 7; and a second differential pressure gauge 26 is also provided. These instruments are all electrically connected to an external PLC controller (not shown).

[0042] Taking the adsorption of the first liquid air adsorber 1 and the regeneration of the second liquid air adsorber 2 as an example, the working principle of this utility model is explained as follows.

[0043] Adsorption and Heating Regeneration Stage: The PLC controller issues a command, opening the first pneumatic valve 34 and the fifth pneumatic valve 38. The raw material liquid air enters from the liquid air feed manifold 3 and flows through the first liquid air adsorber 1 for purification. Simultaneously, the fourteenth pneumatic valve 50 and the twelfth pneumatic valve 45 open, allowing ambient temperature regeneration gas to enter the second liquid air adsorber 2 through the regeneration gas feed manifold 11 for top-down heating and desorption. The remaining valves remain closed.

[0044] Vacuuming stage: After the readings of the second thermometer 23 and the fourth thermometer 30 show that the second liquid air adsorber 2 has returned to room temperature, the PLC closes the twelfth pneumatic valve 45 and the fourteenth pneumatic valve 50. Then, the vacuum pump 33 is started and the eighth pneumatic valve 41 is opened to evacuate the second liquid air adsorber 2 for deep desorption.

[0045] Independent Cooling Stage: After vacuuming, the PLC closes the eighth pneumatic valve 41. Then, it opens the fourth pneumatic valve 37 and the tenth pneumatic valve 43. At this time, a small amount of cryogenic liquid air enters the second liquid air adsorber 2 from the second coolant inlet pipe 10. Since the adsorber is at room temperature, the liquid air undergoes violent flash evaporation. Crucially, the sixth pneumatic valve 39 is closed at this time, and the large amount of gas generated by flash evaporation is discharged to the flare or safe area through the second coolant outlet pipe 18 and the open tenth pneumatic valve 43, without causing any pressure shock to the main outlet pipe. Cooling is complete when the temperature of the second thermometer 23 reaches approximately -183℃. After maintaining the fourth pneumatic valve 37 and the tenth pneumatic valve 43 open for a period of time, the PLC successively closes the tenth pneumatic valve 43 and the fourth pneumatic valve 37, and opens the second pneumatic valve 35 and the sixth pneumatic valve 39, putting the second liquid air adsorber 2 into adsorption mode.

[0046] Switching Phase: The PLC controller automatically executes the switching program according to the pre-set adsorption time. First, the PLC closes the first pneumatic valve 34 and the fifth pneumatic valve 38. Then, the first liquid-air adsorber 1 opens the eleventh pneumatic valve 44 to drain the liquid. After draining, the thirteenth pneumatic valve 49 is opened to heat with regeneration gas. Then, the vacuuming and independent cooling steps are repeated (using the seventh pneumatic valve 40, the third pneumatic valve 36, and the ninth pneumatic valve 42 at this time). A new adsorption cycle begins.

[0047] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A liquid air adsorption and regeneration device, characterized in that: The liquid air adsorption and regeneration device includes: First liquid air adsorber (1); A second liquid air adsorber (2) is arranged in parallel with the first liquid air adsorber (1); The main adsorption circuit includes a liquid air feed main pipe (3) and a liquid air discharge main pipe (8). The liquid air feed main pipe (3) is connected to the bottom of the first liquid air adsorber (1) and the second liquid air adsorber (2) through the first liquid air feed branch pipe (4) and the second liquid air feed branch pipe (5), respectively. The liquid air discharge main pipe (8) is connected to the top of the first liquid air adsorber (1) and the second liquid air adsorber (2) through the first liquid air discharge branch pipe (6) and the second liquid air discharge branch pipe (7), respectively. An independent cooling circuit is provided, comprising a first coolant inlet branch pipe (9), a second coolant inlet branch pipe (10), a first coolant outlet branch pipe (17), and a second coolant outlet branch pipe (18). One end of the first coolant inlet branch pipe (9) is connected to the liquid air inlet main pipe (3), and the other end is connected to the first liquid air inlet branch pipe (4). One end of the second coolant inlet branch pipe (10) is connected to the liquid air inlet main pipe (3), and the other end is connected to the second liquid air inlet branch pipe (5). The first coolant outlet branch pipe (17) is connected to the first liquid air outlet branch pipe (6), and the second coolant outlet branch pipe (18) is connected to the second liquid air outlet branch pipe (7). The valve unit includes a plurality of valves respectively disposed on the first liquid air discharge branch pipe (6), the second liquid air discharge branch pipe (7), the first coolant inlet branch pipe (9), the second coolant inlet branch pipe (10), the first coolant outlet branch pipe (17), and the second coolant outlet branch pipe (18).

2. The liquid air adsorption and regeneration device according to claim 1, characterized in that: The liquid air adsorption and regeneration device also includes: The regeneration circuit includes a first regeneration gas inlet pipe (12) and a second regeneration gas inlet pipe (13) connected to the first liquid air outlet pipe (6) and the second liquid air outlet pipe (7), a regeneration gas inlet main pipe (11), and a first regeneration gas outlet pipe (46) and a second regeneration gas outlet pipe (47) led out from the first liquid air inlet pipe (4) and the second liquid air inlet pipe (5).

3. The liquid air adsorption and regeneration device according to claim 2, characterized in that: The regeneration circuit also includes a vacuum unit, which includes a vacuum pump (33). The vacuum pump (33) is connected to the first regeneration gas feed pipe (12) and the second regeneration gas feed pipe (13) through the vacuum main pipe (16), the first vacuum branch pipe (14) and the second vacuum branch pipe (15), respectively.

4. The liquid air adsorption and regeneration device according to claim 1, characterized in that: The diameter of the first coolant inlet pipe (9) is smaller than the diameter of the first liquid air inlet pipe (4), and the diameter of the second coolant inlet pipe (10) is smaller than the diameter of the second liquid air inlet pipe (5).

5. The liquid air adsorption and regeneration device according to claim 1, characterized in that: The liquid air feed manifold (3) is equipped with a first detector (20), and the liquid air discharge manifold (8) is equipped with a second detector (48). The first detector (20) is used to monitor the impurity content in the liquid air before adsorption, and the second detector (48) is used to monitor the impurity content in the liquid air after adsorption.

6. The liquid air adsorption and regeneration device according to claim 2, characterized in that: The liquid air feed manifold (3) is equipped with a first flow meter (19), and the regenerated gas feed manifold (11) is equipped with a second flow meter (32).

7. The liquid air adsorption and regeneration device according to claim 1, characterized in that: The first liquid air feed pipe (4), the first liquid air discharge pipe (6), the second liquid air feed pipe (5), and the second liquid air discharge pipe (7) are respectively equipped with pressure gauges and thermometers for monitoring fluid parameters.

8. The liquid air adsorption and regeneration device according to claim 1, characterized in that: Both the first liquid air adsorber (1) and the second liquid air adsorber (2) are filled with liquid air adsorbent.

9. The liquid air adsorption and regeneration device according to claim 1, characterized in that: All valves are programmable pneumatic valves.

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