Nitrogen making machine capable of automatically adjusting nitrogen purity

Abstract

The utility model relates to a nitrogen making machine capable of automatically adjusting nitrogen purity, which comprises a nitrogen making machine main machine, an air compressor, an air storage tank, a refrigeration dryer, a nitrogen buffer tank, a nitrogen buffer tank and a proportioning tank, the output end of the air compressor is communicated with the input end of the air storage tank, the output end of the air storage tank is communicated with the input end of the refrigeration dryer, and the nitrogen buffer tank is communicated with the proportioning tank. A concentric-square-shaped input pipe is arranged at the input end of the bottom of the carbon molecular sieve adsorption tower, the output end of the freezing dryer is communicated with the concentric-square-shaped input pipe, a second filter and a first control valve are arranged between the freezing dryer and the concentric-square-shaped input pipe, and a second control valve, a third control valve, a fourth control valve and a fifth control valve are arranged on the concentric-square-shaped input pipe; the design of the air storage tank and the proportioning tank can meet the processing output requirement of constant flow in the process of preparing high-purity nitrogen by the carbon molecular sieve adsorption tower under the condition of ensuring the purity requirement of nitrogen, so that the whole set of equipment can produce and output nitrogen at relatively stable flow.

Description

Technical Field

[0001] The utility model relates to the technical field of nitrogen production equipment, and more specifically, to a nitrogen generator with automatic adjustment of nitrogen purity. Background Technique

[0002] The nitrogen generator is a nitrogen production device designed and manufactured according to the pressure swing adsorption technology. The nitrogen generator uses high-quality imported carbon molecular sieve (CMS) as the adsorbent, and adopts the principle of pressure swing adsorption (PSA) at room temperature to separate air to produce high-purity nitrogen. Usually, two adsorption towers are used in parallel, and the imported pneumatic valves are automatically controlled by the imported PLC to operate alternately for pressurized adsorption and decompression regeneration to complete nitrogen-oxygen separation and obtain the required high-purity nitrogen.

[0003] The difficulty of the nitrogen generator lies in how to accurately adjust the nitrogen purity to 94%-96% while ensuring a relatively stable flow rate. The characteristic of the nitrogen generator is that the higher the flow rate, the lower the purity; conversely, when the flow rate decreases, the purity will increase. There is a flow meter at the gas outlet of the nitrogen generator to control the flow rate, and the flow rate will not exceed the control range of the flow meter. Therefore, the flow rate will not increase significantly, which means that the purity will not decrease significantly. Generally, within a flow rate of 1200 cubic meters, the purity of the nitrogen generator will not be less than 94%. The decrease in the purity of the nitrogen generator does not need to be considered separately.

[0004] When the flow rate at the gas consumption point becomes small, there is a problem that the purity increases, and the oxygen content cannot exceed 4%, that is, the maximum nitrogen purity can only be controlled below 96%. Generally, the program self-adjustment method is used, mainly by extending the adsorption time, that is, slowing down the nitrogen generator. By this method, the nitrogen purity can be reduced, but it is relatively slow, and it takes about 1 hour for adjustment. Moreover, it is required that the nitrogen flow rate is relatively stable during this period, such as the flow rate is controlled at about 1000 cubic meters and cannot change too much, rising and falling sharply. The purity control can be achieved by adjusting the program control time. This method has high requirements for the equipment, long adjustment time, and poor flow stability. The utility model proposes a new solution to the above problems. Content of the Utility Model

[0005] Aiming at the problems existing in the prior art, the purpose of the utility model is to provide a nitrogen generator with automatic adjustment of nitrogen purity to solve the technical problems mentioned in the background technique.

[0006] To solve the above problems, the utility model adopts the following technical solutions.

[0007] A nitrogen generator with automatic nitrogen purity adjustment, including a main body of the nitrogen generator. The main body of the nitrogen generator includes carbon molecular sieve adsorption towers and a controller. There are two groups of carbon molecular sieve adsorption towers. It also includes an air compressor, an air storage tank, a cold dryer, a nitrogen buffer tank, and a proportioning tank. The output end of the air compressor is connected to the input end of the air storage tank, and the output end of the air storage tank is connected to the input end of the cold dryer. A first filter is provided between the air storage tank and the cold dryer. A return-shaped input pipe is provided at the bottom input end of the carbon molecular sieve adsorption tower. The output end of the cold dryer is connected to the return-shaped input pipe. A second filter and a first control valve are provided between the cold dryer and the return-shaped input pipe. A second control valve, a third control valve, a fourth control valve, and a fifth control valve are provided on the return-shaped input pipe. A T-shaped output pipe is provided at the top output end of the carbon molecular sieve adsorption tower. A sixth control valve, a seventh control valve, and an eighth control valve are provided on the T-shaped output pipe. The output end of the T-shaped output pipe is connected to the input end of the nitrogen buffer tank. One input end of the proportioning tank is connected to the output end of the cold dryer, and the other input end of the proportioning tank is connected to the input end of the nitrogen buffer tank. A gas discharge port is provided at the top of the proportioning tank. The controller is electrically connected to the air compressor, the cold dryer, the first control valve, the second control valve, the third control valve, the fourth control valve, the fifth control valve, the sixth control valve, the seventh control valve, and the eighth control valve respectively.

[0008] Preferably, a first flow meter and an evacuation outlet are provided on the output pipe of the nitrogen buffer tank. A ninth control valve and a tenth control valve are provided on the nitrogen discharge port and the evacuation outlet of the nitrogen buffer tank respectively. The ninth control valve and the tenth control valve are electrically connected to the controller respectively.

[0009] In any of the above solutions, preferably, an eleventh control valve and a third filter are provided between the proportioning tank and the nitrogen buffer tank. The eleventh control valve is electrically connected to the controller.

[0010] In any of the above solutions, preferably, a twelfth control valve and a second flow meter are provided between the proportioning tank and the cold dryer. The twelfth control valve is electrically connected to the controller.

[0011] In any of the above solutions, preferably, a one-way valve is provided between the air compressor and the air storage tank.

[0012] In any of the above solutions, preferably, a first evacuation valve is provided at the top of the air storage tank, and a cleaning port is provided at the bottom of the air storage tank. A sealing cover is provided on the cleaning port.

[0013] Compared with the prior art, the advantages of the present utility model are as follows:

[0014] In the present utility model, the design of the air storage tank and the proportioning tank stores compressed air in the air storage tank and mixes it in the proportioning tank output from the carbon molecular sieve adsorption tower. Under the condition of ensuring the purity requirement of nitrogen, it can meet the processing output requirement of constant flow during the preparation of high-purity nitrogen by the carbon molecular sieve adsorption tower, enabling the entire set of equipment to produce and output nitrogen at a relatively stable flow rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 FIG. is a schematic diagram of the overall structure of a nitrogen generator with automatic adjustment of nitrogen purity according to the present utility model.

[0016] Explanation of the reference numerals in the figure:

[0017] 1. Main body of the nitrogen generator; 101. Carbon molecular sieve adsorption tower; 102. Controller; 2. Air compressor; 3. Air storage tank; 4. Refrigerated dryer; 5. Nitrogen buffer tank; 7. Proportioning tank; 9. First filter; 103. U-shaped input pipe; 10. Second filter; 11. First control valve; 12. Second control valve; 13. Third control valve; 14. Fourth control valve; 15. Fifth control valve; 104. T-shaped output pipe; 16. Sixth control valve; 17. Seventh control valve; 18. Eighth control valve; 19. Gas discharge port; 20. First flow meter; 21. Vent outlet; 22. Ninth control valve; 23. Tenth control valve; 24. Eleventh control valve; 25. Third filter; 26. Twelfth control valve; 27. Second flow meter; 28. Check valve; 29. First vent valve; 30. Cleaning port. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model; obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0019] Embodiment:

[0020] Please refer to Figure 1, A nitrogen generator with automatic nitrogen purity adjustment, comprising a main nitrogen generator 1, the main nitrogen generator 1 includes a carbon molecular sieve adsorption tower 101 and a controller 102. There are two groups of carbon molecular sieve adsorption towers 101. It also includes an air compressor 2, an air storage tank 3, a cold dryer 4, a nitrogen buffer tank 5, a nitrogen buffer tank 6 and a proportioning tank 7. The output end of the air compressor 2 is connected to the input end of the air storage tank 3, and the output end of the air storage tank 3 is connected to the input end of the cold dryer 4. A first filter 9 is provided between the air storage tank 3 and the cold dryer 4. A loop-shaped input pipe 103 is provided at the bottom input end of the carbon molecular sieve adsorption tower 101. The output end of the cold dryer 4 is connected to the loop-shaped input pipe 103. A second filter 10 and a first control valve 11 are provided between the cold dryer 4 and the loop-shaped input pipe 103. A second control valve 12, a third control valve 13, a fourth control valve 14 and a fifth control valve 15 are provided on the loop-shaped input pipe 103. A T-shaped output pipe 104 is provided at the top output end of the carbon molecular sieve adsorption tower 101. A sixth control valve 16, a seventh control valve 17 and an eighth control valve 18 are provided on the T-shaped output pipe 104. The output end of the T-shaped output pipe 104 is connected to the input end of the nitrogen buffer tank 5. One input end of the proportioning tank 7 is connected to the output end of the cold dryer 4, and the other input end of the proportioning tank 7 is connected to the input end of the nitrogen buffer tank 5. A gas discharge port 19 is provided at the top of the proportioning tank 7. The controller 102 is electrically connected to the air compressor 2, the cold dryer 4, the first control valve 11, the second control valve 12, the third control valve 13, the fourth control valve 14, the fifth control valve 15, the sixth control valve 16, the seventh control valve 17 and the eighth control valve 18 respectively.

[0021] In this embodiment, a first flow meter 20 and an evacuation outlet 21 are provided on the output pipe of the nitrogen buffer tank 5. A ninth control valve 22 and a tenth control valve 23 are respectively provided on the nitrogen discharge outlet and the evacuation outlet of the nitrogen buffer tank 5. The ninth control valve 22 and the tenth control valve 23 are respectively electrically connected to the controller 102.

[0022] In this embodiment, an eleventh control valve 24 and a third filter 25 are provided between the proportioning tank 7 and the nitrogen buffer tank 5. The eleventh control valve 24 is electrically connected to the controller 102.

[0023] In this embodiment, a twelfth control valve 26 and a second flow meter 27 are provided between the proportioning tank 7 and the cold dryer 4. The twelfth control valve 26 is electrically connected to the controller 102.

[0024] In this embodiment, a one-way valve 28 is provided between the air compressor 2 and the air storage tank 3.

[0025] In this embodiment, a first evacuation valve 29 is provided at the top of the air storage tank 3, and a cleaning port 30 is provided at the bottom of the air storage tank 3. A sealing cover is provided on the cleaning port.

[0026] The working process of the present utility model is as follows:

[0027] Compressed air is prepared by the proportioning tank 7 and the compressed air control system and stored in the proportioning tank 7. After calculation, various industrial and mining parameters due to the reduced flow rate are considered. The required nitrogen purity at the demand side is 94% - 96%, calculated as 95%. The oxygen content of 5% is the optimal parameter. When the purity of the carbon molecular sieve adsorption tower 1 increases due to the change in flow rate, different stages of purity increase in the carbon molecular sieve adsorption tower 1 are selected, namely 96%, 98%, 99%, and 99.9%. After calculation: a certain concentration of nitrogen + air ratio is required to meet the industrial and mining requirement of 1200 cubic meters:

[0028] (1) When the nitrogen purity is 96%, the output of the carbon molecular sieve adsorption tower 1 is 1080 cubic meters (the nitrogen output decreases when the nitrogen concentration increases) + 120 cubic meters of air mixed. The following calculation can be obtained: the oxygen content in 1200 cubic meters of the mixed gas is 1080×4% + 120×21% = 43.2 + 25.2 = 68.4 cubic meters of oxygen. 68.4 oxygen ÷ 1200 cubic meters of the mixed gas = 5.7% oxygen content, and the nitrogen purity is 94.3%, meeting the industrial and mining requirements.

[0029] (2) Nitrogen purity 98%, the output of the carbon molecular sieve adsorption tower 1 is 950 cubic meters (98% nitrogen) + 250 cubic meters of air mixed

[0030] (3) Nitrogen purity 99%, the output of the carbon molecular sieve adsorption tower 1 is 900 cubic meters (99% nitrogen) + 300 cubic meters of air mixed

[0031] (4) Nitrogen purity 99.9%, the output of the carbon molecular sieve adsorption tower 1 is 850 cubic meters (99.9% nitrogen) + 350 cubic meters of air mixed

[0032] Through the analysis of the above data, that is, when the nitrogen purity reaches 99.9% close to 100%, the maximum amount of air required is 350 cubic meters per hour; when the purity is 96% and close to the requirement of 95%, its air demand is 120 cubic meters per hour. Thus, it can be concluded that the additional air volume we need to allocate is in the range of 120 - 350.

[0033] The above is for the industrial and mining demand of 1200 cubic meters of flow rate, adjusted by the method of gas mixing. When the industrial and mining demand for nitrogen becomes smaller, the nitrogen purity will increase. The maximum nitrogen purity increase is generally 99.999%, approaching 100%. At this time, we can consider that the nitrogen generator produces 100% pure nitrogen, and just mix a certain proportion of air. When the on-site demand drops to 1000 cubic meters, 800 cubic meters, and 600 cubic meters, the following mixing ratios will be obtained:

[0034] 1) The oxygen content in 1000 cubic meters of 94% nitrogen is 1000 cubic meters × 6% = 60 cubic meters of oxygen content. Approximately 300 cubic meters of air is required to supplement this oxygen content. This 1000-cubic-meter mixed gas is composed of pure nitrogen produced by the 700-cubic-meter carbon molecular sieve adsorption tower 1 and 300 cubic meters of air.

[0035] 2) The oxygen content in 800 cubic meters of 94% nitrogen is 800 cubic meters × 6% = 48 cubic meters of oxygen content. Approximately 240 cubic meters of air is required to supplement this oxygen content. This 800-cubic-meter mixed gas is composed of pure nitrogen produced by the 560-cubic-meter carbon molecular sieve adsorption tower 1 and 240 cubic meters of air.

[0036] 3) The oxygen content in 600 cubic meters of 94% nitrogen is 600 cubic meters × 6% = 36 cubic meters of oxygen content. Approximately 180 cubic meters of air is required to supplement this oxygen content. This 600-cubic-meter mixed gas is composed of pure nitrogen produced by the 420-cubic-meter carbon molecular sieve adsorption tower 1 and 180 cubic meters of air.

[0037] After calculation, when the actual flow rate required on-site changes, the amount of air mixed gas to be prepared is about 180 to 300 cubic meters. When the flow rate is 1200, the amount of mixed air to be prepared is 120 - 350 cubic meters. From this, it can be shown that no matter how much the flow rate changes and no matter how much the purity changes, the amount of mixed air to be prepared is within a fixed range of 120 - 350 cubic meters per hour. Therefore, configuring compressed air according to this parameter will definitely meet the requirements.

[0038] If it is impossible to adjust under special circumstances, the purity can be analyzed and measured, and venting treatment can be adopted to ensure the safety of on-site use.

[0039] Specifically, air enters the air storage tank 3 through an air compressor, and after passing through a refrigerated dryer 4, a first filter 9, and a second filter 10 to remove oil and water, it then enters a pressure swing adsorption nitrogen generator 1 composed of two towers in parallel, with carbon molecular sieve installed inside the towers. When the towers are operating, the first control valve 11, the second control valve 12, the fifth control valve 15, the sixth control valve 16, and the eighth control valve 18 are opened. Compressed air enters the carbon molecular sieve adsorption tower 101 on the left side through the first control valve 11 and the second control valve 12. During this process, a large amount of oxygen molecules are adsorbed by the carbon molecular sieve in a short time, while very few nitrogen molecules are adsorbed. In this way, a large amount of nitrogen is enriched in the gas phase and enters the nitrogen buffer tank through the sixth control valve 16, the eighth control valve 18, a filter, and a throttle valve, while the oxygen molecules remain in the molecular sieve. At the same time, when the adsorption pressure in the carbon molecular sieve adsorption tower on the right side drops to atmospheric pressure, the adsorbed molecules escape from the carbon molecular sieve and are discharged through the fifth control valve 15, regenerating the molecular sieve. After one minute, when the adsorption is nearly saturated, the first control valve 11, the fifth control valve 15, and the eighth control valve 18 are closed, and the third control valve 13 and the seventh control valve 17 are opened. The gas in the tower enters the carbon molecular sieve adsorption tower on the right side. After about 1 - 2 seconds, the pressures in the two towers are equal. At this time, the first control valve 11, the fourth control valve 14, and the eighth control valve 18 are opened, and the second control valve 12 and the sixth control valve 16 are closed. The carbon molecular sieve adsorption tower on the right side operates, and the carbon molecular sieve adsorption tower on the left side desorbs. Compressed air enters the carbon molecular sieve adsorption tower 101 on the right side through the first control valve 11 and the third control valve 13. Oxygen is adsorbed by the carbon molecular sieve in large amounts, and nitrogen enters the nitrogen buffer tank 5 through the seventh control valve 17, the eighth control valve 18, a filter, and a throttle valve. At the same time, when the adsorption pressure in the left carbon molecular sieve adsorption tower 101 drops to atmospheric pressure, the adsorbed oxygen molecules escape from the carbon molecular sieve and are discharged through the fourth control valve 14 and a silencer. After about one minute, the two towers equalize pressure and switch, repeating the above steps. In this way, nitrogen is continuously generated in a cycle. The product nitrogen in the nitrogen buffer tank 5 passes through a filter, a flow meter, and an outlet stop valve to the point of use.

[0040] The air storage tank 3 is used to store compressed air and mix it with the mixing tank 7 output from the carbon molecular sieve adsorption tower 101. Under the condition of ensuring the purity requirement of nitrogen, it can meet the processing output requirement of constant flow during the preparation of high-purity nitrogen by the carbon molecular sieve adsorption tower 1, enabling the entire set of equipment to produce and output nitrogen at a relatively stable flow rate.

[0041] As described above, it is only the preferred specific embodiment of the present invention; however, the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and its improved concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A nitrogen generator with automatic nitrogen purity adjustment, comprising a main body of the nitrogen generator (1), and the main body of the nitrogen generator (1) includes a carbon molecular sieve adsorption tower (101) and a controller (102). There are two groups of the carbon molecular sieve adsorption towers (101), and it is characterized in that: It also includes an air compressor (2), an air storage tank (3), a refrigerated dryer (4), a nitrogen buffer tank (5) and a proportioning tank (7). The output end of the air compressor (2) is communicated with the input end of the air storage tank (3), the output end of the air storage tank (3) is communicated with the input end of the refrigerated dryer (4), and a first filter (9) is arranged between the air storage tank (3) and the refrigerated dryer (4). A zigzag input pipe (103) is arranged at the bottom input end of the carbon molecular sieve adsorption tower (101). The output end of the refrigerated dryer (4) is communicated with the zigzag input pipe (103), and a second filter (10) and a first control valve (11) are arranged between the refrigerated dryer (4) and the zigzag input pipe (103). A second control valve (12), a third control valve (13), a fourth control valve (14) and a fifth control valve (15) are arranged on the zigzag input pipe (103). A T-shaped output pipe (104) is arranged at the top output end of the carbon molecular sieve adsorption tower (101). A sixth control valve (16), a seventh control valve (17) and an eighth control valve (18) are arranged on the T-shaped output pipe (104). The output end of the T-shaped output pipe (104) is communicated with the input end of the nitrogen buffer tank (5). One of the input ends of the proportioning tank (7) is communicated with the output end of the refrigerated dryer (4), and the other input end of the proportioning tank (7) is communicated with the input end of the nitrogen buffer tank (5). A gas discharge port (19) is arranged at the top of the proportioning tank (7). The controller (102) is electrically connected to the air compressor (2), the refrigerated dryer (4), the first control valve (11), the second control valve (12), the third control valve (13), the fourth control valve (14), the fifth control valve (15), the sixth control valve (16), the seventh control valve (17) and the eighth control valve (18) respectively.

2. The nitrogen generator with automatic nitrogen purity adjustment according to claim 1, wherein: A first flowmeter (20) and an evacuation outlet (21) are arranged on the output pipe of the nitrogen buffer tank (5), and a ninth control valve (22) and a tenth control valve (23) are respectively arranged on the nitrogen discharge port and the evacuation outlet of the nitrogen buffer tank (5), and the ninth control valve (22) and the tenth control valve (23) are respectively electrically connected to the controller (102).

3. The nitrogen generator with automatic nitrogen purity adjustment according to claim 2, characterized in that: An eleventh control valve (24) and a third filter (25) are arranged between the proportioning tank (7) and the nitrogen buffer tank (5), and the eleventh control valve (24) is electrically connected to the controller (102).

4. The nitrogen generator with automatic nitrogen purity adjustment according to claim 3, wherein: A twelfth control valve (26) and a second flowmeter (27) are arranged between the proportioning tank (7) and the refrigerated dryer (4), and the twelfth control valve (26) is electrically connected to the controller (102).

5. The nitrogen generator with automatic nitrogen purity adjustment according to claim 1, characterized in that: A one-way valve (28) is arranged between the air compressor (2) and the air storage tank (3).

6. The nitrogen generator with automatic nitrogen purity adjustment according to claim 1, characterized in that: A first evacuation valve (29) is arranged at the top end of the air storage tank (3), a cleaning port (30) is arranged at the bottom of the air storage tank (3), and a sealing cover is arranged on the cleaning port.

Images