System and method for purifying oxygen in molecular sieve oxygen production process

Abstract

The invention belongs to the technical field of oxygen generation systems, and particularly relates to a system and a method for purifying oxygen in a molecular sieve oxygen generation process. The system comprises a carbon dioxide filter, a moisture filter, an air temporary storage tank, an air compressor, an oil vapor filter, a plurality of adsorption towers, an oxygen storage tank, a nitrogen storage tank and a heat recovery device which are sequentially connected through pipelines and valves, each adsorption tower is filled with the modified molecular sieve material. The MOR molecular sieve structure is modified, so that the anti-aging and anti-pulverization performance of the modified molecular sieve material is improved, the modified MOR molecular sieve structure has the optimal pore structure and adsorption performance, the pore diameter and pore distribution uniformity are improved, a stable state can be kept for a long time, and the adsorption efficiency on nitrogen molecules is improved; the adsorption performance and the adsorption effect are improved, the adsorbent can be recycled, and the service life is prolonged. The heat effect influence and the pressure drop influence are reduced, and the stability and the adsorption efficiency of the system are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of oxygen production systems, and in particular relates to a system and method for purifying oxygen in a molecular sieve oxygen production process. Background Art

[0002] Molecular sieve oxygen production technology is a relatively mature and widely used oxygen production method. However, in actual operation, molecular sieve oxygen production technology still has the following technical problems that need to be solved urgently.

[0003] 1. The performance of molecular sieve adsorbent decreases; (1) Molecular sieve pulverization: In conventional PSA molecular sieve oxygen production technology, during the frequent pressurization and depressurization process, there will be constant collision and friction between molecular sieve particles and between molecular sieve particles and the inner wall of the adsorption tower, which may cause the molecular sieve particles to break and then pulverize. The fine powder thus produced will increase the pressure drop of the adsorption bed, thereby clogging the pipes and / or valves, reducing the porosity of the adsorption bed, resulting in uneven airflow distribution, and affecting the adsorption efficiency.

[0004] (2) Molecular sieve contamination: Since carbon dioxide, moisture, and oil vapor from the compressor in the air are first adsorbed by the molecular sieve, these substances occupy some sites of the molecular sieve and may further undergo chemical reactions or irreversible adsorption, causing the molecular sieve to be contaminated, thereby reducing its adsorption capacity. Although the existing technology uses freeze drying, adsorption drying, CO2 adsorption towers, and precision filters for pretreatment, once these technical means fail, the molecular sieve will be quickly contaminated and fail, affecting the adsorption effect and efficiency.

[0005] (3) Molecular sieve aging: After long-term use, the microporous structure of the molecular sieve may slowly change, such as partial pore collapse, resulting in a gradual decrease in adsorption performance.

[0006] 2. Adsorption bed in the adsorption tower; (1) Influence of thermal effect: In conventional PSA molecular sieve oxygen production technology, adsorption is mainly an exothermic process, while desorption is an endothermic process. During the rapid cycle of PSA, heat cannot be completely transferred out in time, which will cause large temperature fluctuations in the adsorption bed. Specifically, too high a temperature will reduce the adsorption capacity, while too low a temperature will cause incomplete desorption, which will in turn affect the stability and adsorption efficiency of the system.

[0007] (2) Pressure drop effect: The height of the adsorption bed, the size of the molecular sieve particles, the shape of the molecular sieve, the molecular sieve packing density and the degree of molecular sieve pulverization will affect the resistance (pressure drop) of the gas passing through the adsorption bed. Specifically, too high a pressure drop will reduce the porosity of the adsorption bed, resulting in uneven airflow distribution and affecting the adsorption efficiency. At the same time, if the airflow is unevenly distributed, the gas will preferentially pass through the adsorption bed along the path with the least resistance (such as near the inner wall of the adsorption tower or the area with large local voids), resulting in some molecular sieve particles not being fully utilized (channel flow), while others may penetrate prematurely (wall flow), which greatly reduces the adsorption efficiency. Summary of the Invention

[0008] The purpose of the present invention is to provide a system and method for purifying oxygen in a molecular sieve oxygen production process.

[0009] The technical solutions adopted by the present invention to solve the technical problems are as follows: The present invention provides an oxygen purification system for a molecular sieve oxygen production process, comprising: A carbon dioxide filter, a moisture filter, an air temporary storage tank, an air compressor, an oil vapor filter, multiple adsorption towers, an oxygen storage tank, a nitrogen storage tank and a heat recovery device are sequentially connected through pipes and valves; Fill each adsorption column with modified molecular sieve material.

[0010] Furthermore, the upper end of the carbon dioxide filter is connected to the outside air through a pipe, and the lower end is connected to the moisture filter through a carbon dioxide filter valve and a pipe; the lower end of the moisture filter is connected to the air storage tank through a water filter valve and a pipe; the air storage tank is connected to the air compressor through the air storage tank valve and a pipe; the air outlet pipe of the air compressor is connected to the oil vapor filter.

[0011] Furthermore, there are three adsorption towers: a first adsorption tower, a second adsorption tower and a third adsorption tower; the upper end of the first adsorption tower is connected to the heat recovery device through a first heat recovery valve and a pipeline, the upper end of the second adsorption tower is connected to the heat recovery device through a second heat recovery valve and a pipeline, and the upper end of the third adsorption tower is connected to the heat recovery device through a third heat recovery valve and a pipeline; the nitrogen outlet at the lower end of the first adsorption tower is connected to the nitrogen storage tank through a first nitrogen outlet valve and a pipeline, and the oxygen outlet at the lower end of the first adsorption tower is connected to the oxygen storage tank through a first oxygen outlet valve and a pipeline; the nitrogen outlet at the lower end of the second adsorption tower is connected to the nitrogen storage tank through a second nitrogen outlet valve and a pipeline, and the oxygen outlet at the lower end of the second adsorption tower is connected to the oxygen storage tank through a second oxygen outlet valve and a pipeline; the nitrogen outlet at the lower end of the third adsorption tower is connected to the nitrogen storage tank through a third nitrogen outlet valve and a pipeline, and the oxygen outlet at the lower end of the third adsorption tower is connected to the oxygen storage tank through a third oxygen outlet valve and a pipeline.

[0012] Furthermore, it also includes an oxygen concentration detector installed on the connecting pipe between the adsorption tower and the oxygen storage tank.

[0013] Furthermore, the preparation method of the modified molecular sieve material is: S1: Weigh a certain amount of MOR molecular sieve and add the MOR molecular sieve into deionized water to obtain solution A; S2: adding quaternary ammonium hydroxide to solution A in a mass ratio of MOR molecular sieve to quaternary ammonium hydroxide of (5-9): (0.5-1), stirring for 10-15 hours at a temperature of 40-60°C to uniformly disperse the quaternary ammonium hydroxide to obtain solution B; S3: adding lanthanum hydroxide to solution B in a mass ratio of MOR molecular sieve to lanthanum hydroxide of (5-10): (0.1-0.5), stirring at a temperature of 95-150°C for 10-15 hours to uniformly disperse the mixture, to obtain solution C; S4: adding the sodium methoxide methanol solution to the solution C in a mass ratio of MOR molecular sieve to sodium methoxide methanol solution of (1-5): (0.5-2.5), stirring at a temperature of 25-30°C for 3-5 hours to uniformly disperse the solution, and obtaining a solution D; S5: Add a binder to solution D at a mass ratio of (5-10) to (6-15) of MOR molecular sieve and binder. After filtration, washing, and drying, calcinate at a constant temperature of 350-450°C for 3-5h to obtain a modified molecular sieve material.

[0014] Furthermore, the concentration of the MOR molecular sieve in the solution A is 0.05-5 wt %.

[0015] Furthermore, the quaternary ammonium hydroxide salt is selected from one or two of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

[0016] Furthermore, the binder is selected from one or more of kaolin, bentonite, attapulgite, and methyl cellulose.

[0017] Furthermore, in step S5, the drying temperature is 90-120°C.

[0018] The present invention provides a method for purifying oxygen in a molecular sieve oxygen production process, which is implemented using the oxygen purification system in the molecular sieve oxygen production process, and specifically comprises the following steps: (1) The external air first enters the carbon dioxide filter for filtration to remove the carbon dioxide; after filtering out the carbon dioxide, the carbon dioxide filter valve is opened to allow the air to enter the moisture filter for filtration to remove the moisture; after filtering out the moisture, the water filter valve is opened to allow the air to enter the air storage tank; (2) Open the first adsorption tower, open the valve of the air temporary storage tank, pressurize the air through the air compressor, filter out the oil vapor in it through the oil vapor filter, and then send it to the first adsorption tower; the modified molecular sieve material in the first adsorption tower adsorbs nitrogen, opens the first oxygen outlet valve to release oxygen to the oxygen storage tank, and at the same time uses the oxygen concentration detector to detect the purity of the oxygen entering the oxygen storage tank. When the oxygen purity does not meet the requirements, close the first oxygen outlet valve, open the first nitrogen outlet valve to release nitrogen to the nitrogen storage tank; when the first adsorption tower completes the oxygen production process, close the first oxygen outlet valve and the first nitrogen outlet valve, open the first heat recovery valve, and use the heat recovery device to recover waste heat; (3) Open the second adsorption tower, open the valve of the air temporary storage tank, pressurize the air through the air compressor, filter out the oil vapor in it through the oil vapor filter, and then send it to the second adsorption tower; the modified molecular sieve material in the second adsorption tower adsorbs nitrogen, opens the second oxygen outlet valve to release oxygen to the oxygen storage tank, and at the same time uses the oxygen concentration detector to detect the purity of the oxygen entering the oxygen storage tank. When the oxygen purity does not meet the requirements, close the second oxygen outlet valve and open the second nitrogen outlet valve to release nitrogen to the nitrogen storage tank; when the second adsorption tower completes the oxygen production process, close the second oxygen outlet valve and the second nitrogen outlet valve, open the second heat recovery valve, and use the heat recovery device to recover waste heat; (4) Open the third adsorption tower, open the valve of the air temporary storage tank, pressurize the air through the air compressor, filter out the oil vapor in it through the oil vapor filter, and then send it to the third adsorption tower; the modified molecular sieve material in the third adsorption tower adsorbs nitrogen, opens the third oxygen outlet valve to release oxygen to the oxygen storage tank, and at the same time uses the oxygen concentration detector to detect the purity of the oxygen entering the oxygen storage tank. When the oxygen purity does not meet the requirements, close the third oxygen outlet valve, open the third nitrogen outlet valve to release nitrogen to the nitrogen storage tank; when the third adsorption tower completes the oxygen production process, close the third oxygen outlet valve and the third nitrogen outlet valve, open the third heat recovery valve, and use the heat recovery device to recover waste heat; (5) Repeating the above steps (2) to (4) to produce oxygen using molecular sieve physical adsorption and desorption technology.

[0019] The beneficial effects of the present invention are: The present invention provides a system and method for purifying oxygen in a molecular sieve oxygen production process, which has the following advantages over the prior art: 1. Improvement of anti-aging and anti-pulverization properties of modified molecular sieve materials; The present invention improves the anti-aging and anti-pulverization properties of the modified molecular sieve material by modifying the MOR molecular sieve structure, so that the modified MOR molecular sieve structure has an optimal pore structure and adsorption performance, improves the uniformity of the pore size and pore distribution, can maintain a stable state for a long time, improves the adsorption efficiency of nitrogen molecules, improves the adsorption performance and adsorption effect, can be recycled, and increases its service life.

[0020] 2. Reduce the impact of thermal effects and improve the stability and adsorption efficiency of the system; By providing a heat recovery device, the present invention can promptly recover the waste heat in the adsorption tower during and / or after the oxygen production process, transfer the heat in a timely manner, ensure that the temperature of the adsorption bed fluctuates within a smaller range, and greatly improve the stability of the system operation by reducing the impact of the thermal effect on the system, thereby improving the adsorption efficiency.

[0021] 3. The present invention prepares modified molecular sieve materials and utilizes their long-term stability, anti-aging and anti-pulverization properties to reduce the impact of pressure drop, thereby maximizing the gas-solid contact efficiency and minimizing the pressure drop in the adsorption bed (air flow distribution, channel flow, wall flow), increasing the porosity of the adsorption bed, uniformly distributing the air flow, and improving the adsorption efficiency.

[0022] 4. The present invention provides a carbon dioxide filter, a moisture filter and an oil vapor filter to efficiently filter carbon dioxide, moisture and oil vapor in the air, thereby improving the efficiency and reliability of the system operation and thus improving the adsorption efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structural composition of an oxygen purification system in the molecular sieve oxygen production process provided by the present invention.

[0024] Figure 2 The present invention provides a flow chart of a method for purifying oxygen in a molecular sieve oxygen production process.

[0025] In the figure, there are a carbon dioxide filter 1; a moisture filter 2; an air storage tank 3; an air compressor 4; an oil vapor filter 5; a first adsorption tower 601; a second adsorption tower 602; a third adsorption tower 603; an oxygen storage tank 7; a nitrogen storage tank 8; a heat recovery device 9; a carbon dioxide filter valve 10; a water filter valve 11; an air storage tank valve 12; a first nitrogen outlet valve 13; a first oxygen outlet valve 14; a second nitrogen outlet valve 15; a second oxygen outlet valve 16; a third nitrogen outlet valve 17; a third oxygen outlet valve 18; a first heat recovery valve 19; a second heat recovery valve 20; a third heat recovery valve 21; an oxygen concentration detector 22; and a modified molecular sieve material 23. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below with reference to the accompanying drawings.

[0027] In a first aspect, the present invention provides a system for purifying oxygen in a molecular sieve oxygen production process.

[0028] See also Figure 1 As shown, the present invention provides an oxygen purification system in a molecular sieve oxygen production process, which mainly includes: Carbon dioxide filter 1, moisture filter 2, air temporary storage tank 3, air compressor 4, oil vapor filter 5, multiple adsorption towers, oxygen storage tank 7, nitrogen storage tank 8, heat recovery device 9, carbon dioxide filter valve 10, water filter valve 11, air temporary storage tank valve 12, first nitrogen outlet valve 13, first oxygen outlet valve 14, second nitrogen outlet valve 15, second oxygen outlet valve 16, third nitrogen outlet valve 17, third oxygen outlet valve 18, first heat recovery valve 19, second heat recovery valve 20, third heat recovery valve 21, oxygen concentration detector 22 and a large amount of modified molecular sieve material 23.

[0029] Specifically, the upper end of the carbon dioxide filter 1 is connected to the outside air through a pipeline, and the lower end thereof is connected to the moisture filter 2 through a carbon dioxide filter valve 10 and a pipeline.

[0030] Specifically, the carbon dioxide filter 1 is filled with a carbon dioxide adsorbent.

[0031] Specifically, the lower end of the moisture filter 2 is connected to the air temporary storage tank 3 through a water filter valve 11 and a pipeline.

[0032] Preferably, the moisture filter 2 can be specifically an air dryer.

[0033] Specifically, the temporary air storage tank 3 is connected to the air compressor 4 through the temporary air storage tank valve 12 and a pipeline.

[0034] Specifically, the air outlet pipe of the air compressor 4 is connected to the oil vapor filter 5 .

[0035] In a specific embodiment of the present invention, the number of adsorption towers is three, such as Figure 1 As shown, they are the first adsorption tower 601, the second adsorption tower 602 and the third adsorption tower 603 respectively.

[0036] Specifically, the upper end of the first adsorption tower 601 is connected to the heat recovery device 9 through the first heat recovery valve 19 and the pipeline, the upper end of the second adsorption tower 602 is connected to the heat recovery device 9 through the second heat recovery valve 20 and the pipeline, and the upper end of the third adsorption tower 603 is connected to the heat recovery device 9 through the third heat recovery valve 21 and the pipeline.

[0037] Specifically, the nitrogen outlet at the lower end of the first adsorption tower 601 is connected to the nitrogen storage tank 8 through the first nitrogen outlet valve 13 and the pipeline; the oxygen outlet at the lower end of the first adsorption tower 601 is connected to the oxygen storage tank 7 through the first oxygen outlet valve 14 and the pipeline.

[0038] Specifically, the nitrogen outlet at the lower end of the second adsorption tower 602 is connected to the nitrogen storage tank 8 through the second nitrogen outlet valve 15 and the pipeline; the oxygen outlet at the lower end of the second adsorption tower 602 is connected to the oxygen storage tank 7 through the second oxygen outlet valve 16 and the pipeline.

[0039] Specifically, the nitrogen outlet at the lower end of the third adsorption tower 603 is connected to the nitrogen storage tank 8 through the third nitrogen outlet valve 17 and the pipeline; the oxygen outlet at the lower end of the third adsorption tower 603 is connected to the oxygen storage tank 7 through the third oxygen outlet valve 18 and the pipeline.

[0040] In a specific embodiment of the present invention, an oxygen concentration detector 22 is installed on the connecting pipe between the adsorption tower and the oxygen storage tank 7 .

[0041] In a specific embodiment of the present invention, each adsorption tower is filled with modified molecular sieve material 23 .

[0042] Preferably, the modified molecular sieve material 23 is prepared from materials such as MOR molecular sieve, quaternary ammonium hydroxide, lanthanum hydroxide, and sodium methoxide methanol solution. Specifically, the MOR molecular sieve is first blended with deionized water to obtain a mixed solution A; then a quaternary ammonium hydroxide salt, such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc. is added thereto, and the quaternary ammonium cations in the quaternary ammonium hydroxide salt will undergo ion exchange with the cations in the MOR molecular sieve to form a MOR molecular sieve containing quaternary ammonium cations. At this time, the pore structure of the MOR molecular sieve is preliminarily changed by the action of the quaternary ammonium hydroxide salt, providing the necessary basic conditions for subsequent reactions; lanthanum hydroxide is then added thereto for a complex reaction, that is, the quaternary ammonium cations contained in the MOR molecular sieve will form complexes with the lanthanum ions, and these complexes are connected by molecular bonds in the porous three-dimensional structure to form a porous structure, which can achieve efficient adsorption of nitrogen; and then sodium methoxide methanol solution is added thereto. As an organic solvent, sodium methoxide methanol solution has good solubility, which helps to improve the dispersibility between the MOR molecular sieve and the binder, so that the MOR molecular sieve is more evenly dispersed in the binder, which helps to improve the performance of the modified molecular sieve material 23.

[0043] The present invention modifies the structure of the MOR molecular sieve to produce a modified molecular sieve material 23 with an optimized pore structure and adsorption performance, improving the uniformity of the pore size and pore distribution. Furthermore, the presence of the lanthanum ion complex increases the number of pores in the MOR molecular sieve, enabling the adsorption of large quantities of nitrogen molecules, thereby improving the adsorption capacity and efficiency of nitrogen molecules and achieving optimal nitrogen-oxygen separation. Furthermore, the modified molecular sieve material 23 produced by the present invention exhibits good structural stability, resistance to pulverization and aging, and is recyclable, thereby increasing its service life.

[0044] In a second aspect, the present invention provides a method for purifying oxygen in a molecular sieve oxygen production process. The method is implemented using the oxygen purification system in a molecular sieve oxygen production process provided in the first aspect.

[0045] See also Figure 2 As shown, the present invention provides a method for purifying oxygen in a molecular sieve oxygen production process, which mainly includes the following steps: Step 1: First, prepare a modified molecular sieve material; S1: Weigh a certain amount of MOR molecular sieve and add the MOR molecular sieve into deionized water to obtain solution A; Preferably, in solution A, the concentration of MOR molecular sieve is 0.05-5wt%; More preferably, in solution A, the concentration of MOR molecular sieve is 1-2 wt %; Most preferably, in solution A, the concentration of MOR molecular sieve is 1.5 wt %.

[0046] S2: adding quaternary ammonium hydroxide to solution A at a mass ratio of (5-9) to (0.5-1) of MOR molecular sieve (the mass of MOR molecular sieve weighed in step S1), stirring for 10-15 hours at a temperature of 40-60° C. to uniformly disperse the quaternary ammonium hydroxide, to obtain solution B; Preferably, the mass ratio of MOR molecular sieve to quaternary ammonium hydroxide salt is (6-8): (0.55-0.65); Preferably, the quaternary ammonium hydroxide salt is selected from one or two of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide; More preferably, the quaternary ammonium hydroxide salt is tetramethylammonium hydroxide.

[0047] S3: adding lanthanum hydroxide to solution B at a mass ratio of (5-10) to (0.1-0.5) of MOR molecular sieve (the mass of MOR molecular sieve weighed in step S1), and stirring at a temperature of 95-150° C. for 10-15 hours to uniformly disperse the mixture, thereby obtaining solution C; Preferably, the mass ratio of MOR molecular sieve to lanthanum hydroxide is (7-8): (0.1-0.3).

[0048] S4: adding the sodium methoxide methanol solution to Solution C in a mass ratio of (1-5) to (0.5-2.5) of MOR molecular sieve (the mass of MOR molecular sieve weighed in step S1) to the sodium methoxide methanol solution, stirring for 3-5 hours at a temperature of 25-30° C. to uniformly disperse the solution, thereby obtaining Solution D; Preferably, the mass ratio of MOR molecular sieve to sodium methoxide methanol solution is (2-4): (0.5-1.5).

[0049] S5: Add a binder to solution D in a mass ratio of (5-10) to (6-15) of MOR molecular sieve (the mass of MOR molecular sieve weighed in step S1). After filtration, washing, and drying, calcination at a constant temperature of 350-450°C for 3-5 hours is performed to obtain a modified molecular sieve material.

[0050] Preferably, the mass ratio of MOR molecular sieve to binder is (7-8): (7-10); Preferably, the binder is selected from one or more of kaolin, bentonite, attapulgite, and methylcellulose; More preferably, the binder is a combination of kaolin and methylcellulose; Preferably, during washing, acetone and water are used alternately for 3-5 times; Preferably, the drying temperature is 90-120°C.

[0051] Step 2: Fill each adsorption tower with the prepared modified molecular sieve material; Step 3: The external air first enters the carbon dioxide filter 1 for filtration to remove the carbon dioxide therein; after the carbon dioxide is filtered out, the carbon dioxide filter valve 10 is opened to allow the air to enter the moisture filter 2 for filtration to remove the moisture therein; after the moisture is filtered out, the water filter valve 11 is opened to allow the air to enter the air temporary storage tank 3; Step 4: Open the first adsorption tower 601 and open the air temporary storage tank valve 12. The air is pressurized by the air compressor 4 and then filtered through the oil vapor filter 5 to remove the oil vapor before being sent to the first adsorption tower 601. The modified molecular sieve material 23 in the first adsorption tower 601 adsorbs nitrogen. The first oxygen outlet valve 14 is opened to release oxygen to the oxygen storage tank 7. At the same time, the oxygen purity entering the oxygen storage tank 7 is detected by the oxygen concentration detector 22. When the oxygen purity does not meet the requirement, the first oxygen outlet valve 14 is closed and the first nitrogen outlet valve 13 is opened to release nitrogen to the nitrogen storage tank 8. When the first adsorption tower 601 completes the oxygen production process, the first oxygen outlet valve 14 and the first nitrogen outlet valve 13 are closed, the first heat recovery valve 19 is opened, and the heat recovery device 9 is used to recover waste heat.

[0052] Step 5: Open the second adsorption tower 602 and open the air temporary storage tank valve 12. The air is pressurized by the air compressor 4 and then filtered through the oil vapor filter 5 to remove the oil vapor before being sent to the second adsorption tower 602. The modified molecular sieve material 23 in the second adsorption tower 602 adsorbs nitrogen. The second oxygen outlet valve 16 is opened to release oxygen to the oxygen storage tank 7. At the same time, the oxygen purity entering the oxygen storage tank 7 is detected by the oxygen concentration detector 22. When the oxygen purity does not meet the requirement, the second oxygen outlet valve 16 is closed and the second nitrogen outlet valve 15 is opened to release nitrogen to the nitrogen storage tank 8. When the second adsorption tower 602 completes the oxygen production process, the second oxygen outlet valve 16 and the second nitrogen outlet valve 15 are closed, the second heat recovery valve 20 is opened, and the heat recovery device 9 is used to recover waste heat.

[0053] Step 6: Open the third adsorption tower 603 and open the air temporary storage tank valve 12. The air is pressurized by the air compressor 4 and then filtered through the oil vapor filter 5 to remove the oil vapor before being sent to the third adsorption tower 603. The modified molecular sieve material 23 in the third adsorption tower 603 adsorbs nitrogen. The third oxygen outlet valve 18 is opened to release oxygen to the oxygen storage tank 7. At the same time, the oxygen purity entering the oxygen storage tank 7 is detected by the oxygen concentration detector 22. When the oxygen purity does not meet the requirement, the third oxygen outlet valve 18 is closed and the third nitrogen outlet valve 17 is opened to release nitrogen to the nitrogen storage tank 8. When the third adsorption tower 603 completes the oxygen production process, the third oxygen outlet valve 18 and the third nitrogen outlet valve 17 are closed, the third heat recovery valve 21 is opened, and the heat recovery device 9 is used to recover waste heat.

[0054] Step 7: Repeat steps 4 to 6 to produce oxygen using molecular sieve physical adsorption and desorption technology.

[0055] The present invention discloses a system and method for purifying oxygen in a molecular sieve oxygen production process. Those skilled in the art can refer to the contents of this article and appropriately improve the process parameters to achieve the desired results. It should be noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The products of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the products described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

Claims

1. The oxygen purification system in the molecular sieve oxygen production process is characterized by: include: A carbon dioxide filter, a moisture filter, an air temporary storage tank, an air compressor, an oil vapor filter, multiple adsorption towers, an oxygen storage tank, a nitrogen storage tank and a heat recovery device are sequentially connected through pipes and valves; Fill each adsorption column with modified molecular sieve material.

2. The oxygen purification system in the molecular sieve oxygen production process according to claim 1, characterized in that: The upper end of the carbon dioxide filter is connected to the outside air through a pipeline, and the lower end is connected to the moisture filter through a carbon dioxide filter valve and a pipeline; the lower end of the moisture filter is connected to the air temporary storage tank through a water filter valve and a pipeline; the air temporary storage tank is connected to the air compressor through the air temporary storage tank valve and a pipeline; the air outlet pipeline of the air compressor is connected to the oil vapor filter.

3. The oxygen purification system in the molecular sieve oxygen production process according to claim 1, characterized in that: There are three adsorption towers: a first adsorption tower, a second adsorption tower, and a third adsorption tower; the upper end of the first adsorption tower is connected to a heat recovery device through a first heat recovery valve and a pipeline, the upper end of the second adsorption tower is connected to the heat recovery device through a second heat recovery valve and a pipeline, and the upper end of the third adsorption tower is connected to the heat recovery device through a third heat recovery valve and a pipeline; the nitrogen outlet at the lower end of the first adsorption tower is connected to a nitrogen storage tank through a first nitrogen outlet valve and a pipeline, and the oxygen outlet at the lower end of the first adsorption tower is connected to the oxygen storage tank through a first oxygen outlet valve and a pipeline; the nitrogen outlet at the lower end of the second adsorption tower is connected to the nitrogen storage tank through a second nitrogen outlet valve and a pipeline, and the oxygen outlet at the lower end of the second adsorption tower is connected to the oxygen storage tank through a second oxygen outlet valve and a pipeline; the nitrogen outlet at the lower end of the third adsorption tower is connected to the nitrogen storage tank through a third nitrogen outlet valve and a pipeline, and the oxygen outlet at the lower end of the third adsorption tower is connected to the oxygen storage tank through a third oxygen outlet valve and a pipeline.

4. The oxygen purification system in the molecular sieve oxygen production process according to claim 1, characterized in that: It also includes an oxygen concentration detector installed on the connecting pipe between the adsorption tower and the oxygen storage tank.

5. The oxygen purification system in the molecular sieve oxygen production process according to claim 1, characterized in that: The preparation method of the modified molecular sieve material is: S1: Weigh a certain amount of MOR molecular sieve and add the MOR molecular sieve into deionized water to obtain solution A; S2: adding quaternary ammonium hydroxide to solution A in a mass ratio of MOR molecular sieve to quaternary ammonium hydroxide of (5-9): (0.5-1), stirring for 10-15 hours at a temperature of 40-60°C to uniformly disperse the quaternary ammonium hydroxide to obtain solution B; S3: adding lanthanum hydroxide to solution B in a mass ratio of MOR molecular sieve to lanthanum hydroxide of (5-10): (0.1-0.5), stirring at a temperature of 95-150°C for 10-15 hours to uniformly disperse the mixture, to obtain solution C; S4: adding the sodium methoxide methanol solution to the solution C in a mass ratio of MOR molecular sieve to sodium methoxide methanol solution of (1-5): (0.5-2.5), stirring at a temperature of 25-30°C for 3-5 hours to uniformly disperse the solution, and obtaining a solution D; S5: Add a binder to solution D at a mass ratio of (5-10) to (6-15) of MOR molecular sieve and binder. After filtration, washing, and drying, calcinate at a constant temperature of 350-450°C for 3-5h to obtain a modified molecular sieve material.

6. The oxygen purification system in the molecular sieve oxygen production process according to claim 5, characterized in that: The concentration of the MOR molecular sieve in the solution A is 0.05-5 wt %.

7. The oxygen purification system in the molecular sieve oxygen production process according to claim 5, characterized in that: The quaternary ammonium hydroxide salt is selected from one or two of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide and tetrabutylammonium hydroxide.

8. The oxygen purification system in the molecular sieve oxygen production process according to claim 5, characterized in that: The binder is selected from one or more of kaolin, bentonite, attapulgite and methyl cellulose.

9. The oxygen purification system in the molecular sieve oxygen production process according to claim 5, characterized in that: In step S5, the drying temperature is 90-120°C.

10. A method for purifying oxygen in a molecular sieve oxygen production process, characterized in that: The oxygen purification system in the molecular sieve oxygen production process according to any one of claims 1 to 9 is implemented, comprising the following steps: (1) The external air first enters the carbon dioxide filter for filtration to remove the carbon dioxide; after filtering out the carbon dioxide, the carbon dioxide filter valve is opened to allow the air to enter the moisture filter for filtration to remove the moisture; after filtering out the moisture, the water filter valve is opened to allow the air to enter the air temporary storage tank; (2) Open the first adsorption tower, open the valve of the air temporary storage tank, pressurize the air through the air compressor, filter out the oil vapor in it through the oil vapor filter, and then send it to the first adsorption tower; the modified molecular sieve material in the first adsorption tower adsorbs nitrogen, opens the first oxygen outlet valve to release oxygen to the oxygen storage tank, and at the same time uses the oxygen concentration detector to detect the purity of the oxygen entering the oxygen storage tank. When the oxygen purity does not meet the requirements, close the first oxygen outlet valve, open the first nitrogen outlet valve to release nitrogen to the nitrogen storage tank; when the first adsorption tower completes the oxygen production process, close the first oxygen outlet valve and the first nitrogen outlet valve, open the first heat recovery valve, and use the heat recovery device to recover waste heat; (3) Open the second adsorption tower, open the valve of the air temporary storage tank, pressurize the air through the air compressor, filter out the oil vapor in it through the oil vapor filter, and then send it to the second adsorption tower; the modified molecular sieve material in the second adsorption tower adsorbs nitrogen, opens the second oxygen outlet valve to release oxygen to the oxygen storage tank, and at the same time uses the oxygen concentration detector to detect the purity of the oxygen entering the oxygen storage tank. When the oxygen purity does not meet the requirements, close the second oxygen outlet valve and open the second nitrogen outlet valve to release nitrogen to the nitrogen storage tank; when the second adsorption tower completes the oxygen production process, close the second oxygen outlet valve and the second nitrogen outlet valve, open the second heat recovery valve, and use the heat recovery device to recover waste heat; (4) Open the third adsorption tower, open the valve of the air temporary storage tank, pressurize the air through the air compressor, filter out the oil vapor in it through the oil vapor filter, and then send it to the third adsorption tower; the modified molecular sieve material in the third adsorption tower adsorbs nitrogen, opens the third oxygen outlet valve to release oxygen to the oxygen storage tank, and at the same time uses the oxygen concentration detector to detect the purity of the oxygen entering the oxygen storage tank. When the oxygen purity does not meet the requirements, close the third oxygen outlet valve, open the third nitrogen outlet valve to release nitrogen to the nitrogen storage tank; when the third adsorption tower completes the oxygen production process, close the third oxygen outlet valve and the third nitrogen outlet valve, open the third heat recovery valve, and use the heat recovery device to recover waste heat; (5) Repeating the above steps (2) to (4) to produce oxygen using molecular sieve physical adsorption and desorption technology.

Images