Method for realizing low energy consumption oxygen production by using tower-less VPSA oxygen production system

Abstract

The present invention relates to the field of gas separation technology, and aims to provide a method for realizing low-energy oxygen production by utilizing a towerless VPSA oxygen production system. The oxygen production system comprises an air filter, a blower, a cooler and an adsorption skid-mounted module which are sequentially arranged on a blast pipeline; the adsorption skid-mounted module comprises two or more adsorption submodules which are arranged in parallel and have the same structure. In this method, while a certain submodule is in an adsorption oxygen production operation state, another submodule is used for desorption and regeneration treatment, so as to back up each other and switch cyclically; and when switching operation, one or more submodules are connected in sequence to equalize the pressure drop, and then the operation of commissioning and regeneration is performed respectively. This method utilizes the switching of the operation state of the adsorption submodule to significantly improve the high precision and rapid responsiveness of the system control, and improve redundancy and reliability; the simplified equipment composition in the system can significantly reduce complexity and maintenance costs; while simplifying the oxygen production process, energy consumption is significantly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of gas separation, and in particular to a method for realizing low-energy oxygen production by utilizing a tower-free VPSA oxygen production system. Background Art

[0002] The core of vacuum pressure swing adsorption (VPSA) oxygen production technology lies in the selection of adsorbents, the design of adsorption towers and the control of pressure swing adsorption processes. Adsorbents usually have the characteristics of strong selective adsorption, that is, the adsorption amount of different gases on the adsorbent is different, and the adsorption amount of a specific gas on the adsorbent will change with the change of pressure. During the adsorption process, when the mixed gas contacts the adsorbent, the impurity components with strong adsorption capacity will be selectively adsorbed on the adsorbent, while the components with weak adsorption capacity will be enriched in the remaining gas. By controlling the change of pressure, precise control of the adsorption and desorption processes can be achieved, thereby realizing the separation and purification of gases. Compared with traditional cryogenic oxygen production methods, VPSA technology has the advantages of simple operation, less equipment investment and good environmental performance. Therefore, it has gradually been widely used in industrial fields such as steel, chemical industry, and metallurgy.

[0003] However, traditional VPSA technology usually uses large adsorption towers as separation equipment. Although it can achieve the separation and purification of oxygen, the setting of the adsorption tower type pressure vessel also increases the overall complexity and maintenance cost of the equipment, and the manufacturing cost is high and difficult to standardize.

[0004] Therefore, the development of a low-cost, low-energy, highly reliable and redundant tower-free VPSA oxygen production technology has important practical value and broad market prospects. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a method for achieving low-energy consumption oxygen production by utilizing a tower-less VPSA oxygen production system.

[0006] To solve the technical problem, the solution of the present invention is:

[0007] Provided is a method for achieving low-energy oxygen production using a tower-less VPSA oxygen production system, the method being achieved based on the following tower-less VPSA oxygen production system;

[0008] The system includes an air filter, a blower, a cooler and an adsorption skid-mounted module which are sequentially arranged on the blast pipeline; the adsorption skid-mounted module includes more than two adsorption submodules arranged in parallel and having the same structure, an air intake pipe and an exhaust pipe are arranged at the bottom of each adsorption submodule, the air intake pipe is connected to the blast pipeline through the blast main pipe, and the exhaust pipe is connected to the exhaust pipeline through the exhaust main pipe; an oxygen exhaust pipe and a regeneration pipe are arranged at the top of each adsorption submodule, the oxygen exhaust pipe is connected to the oxygen enrichment pipeline through the oxygen outlet main pipe, and the regeneration pipe is connected to the oxygen enrichment pipe through the regeneration main pipe The exhaust gas pipeline is connected to the exhaust gas main pipe; valves are provided on each pipeline, and an exhaust gas check valve is provided at the end of the exhaust gas main pipe, and a regeneration check valve is provided at the end of the regeneration main pipe; the oxygen-enriched pipeline is connected to the oxygen balance tank and the oxygen storage tank in sequence, and valves are provided at the inlets and outlets of the two tanks; the exhaust gas pipeline is connected to the vacuum pump and the muffler in sequence; the adsorption submodule includes at least one oxygen-generating adsorption tube, and if there are multiple oxygen-generating adsorption tubes, they are connected in parallel; the oxygen-generating adsorption tube is an axial oxygen-generating adsorption tube or a radial oxygen-generating adsorption tube;

[0009] The oxygen production method specifically comprises:

[0010] (1) Take the oxygen production system as an example, which is provided with three adsorption submodules, namely the first adsorption submodule, the second adsorption submodule and the third adsorption submodule, and is switched in parallel; it is assumed that the first adsorption submodule is in the waiting regeneration stage after the adsorption is completed, the second adsorption submodule is in the operation stage of air intake adsorption and oxygen production, and the third adsorption submodule is in the waiting operation stage after desorption and regeneration;

[0011] (2) connecting the first adsorption submodule with the third adsorption submodule at a relatively low pressure to equalize the pressure drop, recovering the oxygen enriched in the first adsorption submodule and transferring it to the third adsorption submodule, while increasing the pressure of the third adsorption submodule;

[0012] (3) Using a vacuum pump to extract the remaining gas in the first adsorption submodule, and discharge the waste gas through the exhaust pipe and the waste gas pipeline; while the first adsorption submodule is being vacuumed and desorbed, the adsorption and oxygen production phase of the second adsorption submodule is nearly completed and is ready to enter the desorption and regeneration process;

[0013] (4) stopping the oxygen production operation of the second adsorption submodule, performing a second pressure drop operation on it and the third adsorption submodule that has been pressurized and recovered a portion of the oxygen, further recovering and transferring the oxygen-rich gas in the second adsorption submodule, and continuing to increase the pressure of the third adsorption submodule; after the third adsorption submodule receives the oxygen-rich gas from the first adsorption submodule and the second adsorption submodule respectively, switching it to the operation stage of air intake adsorption oxygen production;

[0014] At this time, the third adsorption submodule is in the operation stage of air intake adsorption and oxygen production, the second adsorption submodule is in the stage of waiting for regeneration after completing adsorption, and the first adsorption submodule is in the stage of waiting for operation after desorption and regeneration;

[0015] (5) Using the automatic control equipment to control each valve, and repeatedly executing the operation contents of steps (1) to (4) according to the set program; during the switching operation of each adsorption submodule, the time node of the switching operation is confirmed according to the preset control threshold value and the real-time pressure value and temperature value in the pipeline obtained by each sensor;

[0016] (6) For an oxygen production system with only two adsorption submodules, while one submodule is in the adsorption oxygen production operation state, the other submodule is in the desorption regeneration process, and the two submodules serve as backup for each other and switch cyclically; when switching operation, the two adsorption submodules are first connected to equalize the pressure drop, and then the operation of commissioning and regeneration is performed respectively;

[0017] For an oxygen production system with more than three adsorption submodules, the operations are performed in accordance with the contents of steps (1) to (4), and more submodules are in the waiting stage for commissioning.

[0018] As a preferred embodiment of the present invention, the specifications of a single oxygen production adsorption tube in the adsorption submodule are as follows: the total axial length is 700 mm, the inner diameter of the end is 200 mm, and the internal geometric volume is less than 0.025 m 3 .

[0019] As a preferred embodiment of the present invention, the valves on each pipeline refer to any one of the electrically controlled regulating valves including hydraulic valves, pneumatic valves or solenoid valves, and the actuators of each electrically controlled regulating valve are connected to the automatic control device through cables; each pipeline is provided with a pressure sensor and a temperature sensor, which are connected to the automatic control device through signal lines respectively; the automatic control device is a DDC (Direct Digital Control) controller or a PLC (Programmable Logic Controller) controller.

[0020] As a preferred solution of the present invention, the two ends of the radial oxygen production adsorption tube are respectively fixedly connected to the tube inlet section and the tube outlet section by welding, and the three together form an adsorption tube body with an internal cavity;

[0021] A central through hole is provided on the end surface of the inlet section and the outlet section of the pipe body respectively; an inlet end cover and an outlet end cover are provided opposite to the end surfaces of the two and fixed by bolt connection; a vent hole is provided in the center of the inlet end cover and the outlet end cover;

[0022] An inner clamp and an outer clamp are fixedly arranged on the inner side of the end face of the inlet section of the tube body, and a closed drying chamber is formed between the two to be filled with desiccant; two through holes connected to the drying chamber are arranged on the end face of the inlet section of the tube body, and plugs are arranged in the through holes;

[0023] An outer cylinder and an inner cylinder are concentrically nested and installed on the inner side of the end face of the outlet section of the pipe body, a gas transmission cavity is formed between the outer cylinder and the pipe body, an adsorption chamber is formed between the outer cylinder and the inner cylinder, the inner cavity of the inner cylinder serves as an oxygen-enriched chamber and is connected to the central through hole on the end face of the outlet section of the pipe body and the vent hole of the outlet end cover; the non-installed ends of the outer cylinder and the inner cylinder are close to the inlet section of the pipe body and are blocked with a diverter block, so that the adsorption chamber becomes a closed structure for filling the adsorbent; two through holes connected to the adsorption chamber are provided on the end face of the outlet section of the pipe body, and plugs are provided in the through holes;

[0024] The inner and outer clips, the outer tube and the inner tube are all made of rigid breathable materials.

[0025] As a preferred embodiment of the present invention, the inner diameters of the tube inlet section and the tube outlet section are the same and both are larger than the inner diameter of the tube body; the structures and sizes of the inlet end cover and the outlet end cover are the same; the diverter block has a conical structure with a larger top and a smaller bottom, and the diameter of its upper end face is the same as the outer diameter of the outer cylinder.

[0026] As a preferred solution of the present invention, the outlet section of the inner cylinder is tightly fitted with the inner wall surface of the central through hole of the end face of the tube body outlet section to achieve fixed installation, and the inner cylinder outlet section protrudes from the outer surface of the end face, and an annular colloid sealing ring is provided on the outer edge of the protruding part of the inner cylinder.

[0027] As a preferred embodiment of the present invention, the inner wall surfaces of the vent holes of the inlet end cover and the outlet end cover are provided with threads; inner countersunk holes surrounding the central vent hole are provided on the inner sides of the inlet end cover and the outlet end cover, and the two are installed with their inner countersunk holes corresponding to the central through holes on the end faces of the inlet section and the outlet section of the pipe body respectively.

[0028] As a preferred embodiment of the present invention, the end faces of the tube inlet section and the tube outlet section are provided with the same number of sunken screw holes, and the inlet end cover and the outlet end cover are correspondingly provided with the same number of connecting holes, and a plurality of bolts are respectively passed through the connecting holes and installed in the screw holes, so that the inlet end cover and the outlet end cover are respectively fixed to the end faces of the tube inlet section and the tube outlet section.

[0029] As a preferred embodiment of the present invention, the inner end faces of the inlet end cover and the outlet end cover are provided with concentrically arranged outer countersunk holes and annular grooves, and a sealing ring is provided in the annular groove; the installation position of the outer countersunk hole corresponds to the plugs on the end faces of the inlet section and the outlet section of the pipe body, and the width of the outer countersunk hole is slightly larger than the diameter of the plug, so that the protruding part of the plug can fall into the outer countersunk hole after installation.

[0030] As a preferred solution of the present invention, the inlet end cover and the outlet end cover have a "J"-shaped transverse cross section, and the heads of the bolts after installation are not higher than the outermost surfaces of the inlet end cover and the outlet end cover.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. This method can realize the flexible switching of the operating state of the adsorption submodule by relying on the control strategy built into the automatic control device; it can significantly improve the high precision and rapid responsiveness of system control, and further improve redundancy and reliability;

[0033] 2. The present invention abandons the traditional large-scale adsorption tower structure through innovative design and optimization, thereby simplifying the equipment composition and significantly reducing the complexity and maintenance cost of the equipment.

[0034] 3. The adsorption skid-mounted module in the present invention achieves the high efficiency of personalized production through standardized design, factory assembly, and large-scale customization, while providing a wider flow adjustment range. In addition, the parallel connection of multiple oxygen adsorption tubes can fully stabilize the pressure fluctuations in the oxygen production process, significantly improving the reliability, stability and efficiency of the VPSA oxygen production process. The standard adsorption submodule composed of these oxygen adsorption tubes adopts a pressure-free vessel design, which further enhances the safety of the oxygen production system.

[0035] 4. When multiple groups of adsorption skid-mounted modules are connected in parallel to produce oxygen, only one set of blower and vacuum pump can be configured, or one can be used and the other can be used as a backup. No additional equipment is required in the system, which simplifies the oxygen production process and significantly reduces the energy consumption in the VPSA oxygen production process.

[0036] 5. The present invention adds a cooler after the blower (a well-known heat exchanger can be used, which can be air-cooled or water-cooled) to improve the adsorption capacity and efficiency of the adsorbent for gas components during the separation process of the vacuum pressure swing adsorption gas, and effectively prevent the risks caused by excessively high blast temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of a single-module towerless VPSA oxygen production system;

[0038] Figure 2 It is a structural diagram of a multi-module parallel tower-less VPSA oxygen production system;

[0039] Figure 3 It is a structural diagram of the adsorption skid-mounted module;

[0040] Figure 4 It is a flow chart of the control module;

[0041] Figure 5It is a schematic diagram of an axial oxygen production adsorption tube;

[0042] Figure 6 It is a schematic diagram of a radial oxygen adsorption tube.

[0043] The accompanying drawings are marked as follows: 101 blower pipeline; 102 exhaust pipeline; 103 oxygen enrichment pipeline; 104 blower main pipe; 105 oxygen outlet main pipe; 106 regeneration main pipe; 2 air filter; 3 blower; 4 cooler; 5 adsorption skid-mounted module; 602-605 control valves; 7 vacuum pump; 8 muffler; 9 oxygen balance tank; 10 oxygen storage tank; 11 intake valve; 12 exhaust valve; 13 oxygen outlet valve; 14 regeneration valve; 15 adsorption submodule; 16 regeneration check valve; 17 exhaust check valve; 100 automatic control equipment; 200 sensor; 300 actuator.

[0044] Figure 7 It is a schematic diagram of the cross-sectional structure of a radial oxygen production adsorption tube;

[0045] Figure 8 It is a schematic diagram of the overall structure of a radial oxygen production adsorption tube;

[0046] Fig. 9 It is a structural schematic diagram of the inlet section of the pipe body;

[0047] Fig.10 It is a schematic diagram of the structure of the outlet section of the pipe body;

[0048] Fig.11 It is a schematic diagram of the structure of the inlet end cover;

[0049] Fig.12 It is a structural diagram of the outlet end cover.

[0050] The figures are marked as follows: 21, tube body; 22, tube body inlet section; 23, tube body outlet section; 24, inlet end cover; 25, screw hole; 2601, desiccant feed port; 2602, desiccant inlet plug; 2701, adsorbent feed port; 2702, adsorbent inlet plug; 28, outer cylinder; 29, adsorption chamber; 30, inner cylinder; 31, oxygen-enriched chamber; 32, gas transmission chamber; 33, colloid sealing ring; 34, outlet end cover; 35, bolt; 36, drying chamber; 3601, outer clip; 3602, inner clip; 37, connecting hole; 38, sealing ring; 39, inner countersunk hole; 40, outer countersunk hole; 41, diverter block. DETAILED DESCRIPTION

[0051] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0052] Part 1. Description of equipment layout in the system

[0053] The specific structure of the low-energy tower-less VPSA oxygen production system is as follows: Figure 1As shown, the system includes a blast pipeline 101, an adsorption skid module 5, an exhaust pipeline 102 and an oxygen enrichment pipeline 103. The blast pipeline 101 is provided with an air filter 2, a blower 3, a cooler 4 and several groups of adsorption skid modules 5 in sequence. For example, Figure 2 In the embodiment shown, two groups of adsorption skid-mounted modules 5 are provided. The oxygen-enriched gas outlet of the adsorption skid-mounted module 5 is connected to the oxygen-enriched pipeline 103, and the oxygen-enriched pipeline 103 is provided with a control valve 605, an oxygen balance tank 9, a control valve 602, an oxygen storage tank 10 and a control valve 603 in sequence. It is also possible to simplify the process in one piece according to the on-site conditions, and change the oxygen balance tank 9 and the oxygen storage tank 10 to only one oxygen storage tank 10. The exhaust gas outlet of the adsorption skid-mounted module 5 is connected to the exhaust gas pipeline 102, and the exhaust gas pipeline 102 is provided with a vacuum pump 7 and a muffler 8 in sequence.

[0054] In the adsorption skid-mounted module 5, there are three adsorption submodules 15 arranged in parallel, and an exhaust gas main pipe, a blast main pipe 104, an oxygen outlet main pipe 105 and a regeneration main pipe 106 connected to each adsorption submodule 15. Each adsorption submodule 15 is composed of a plurality of oxygen-generating adsorption pipes arranged in parallel. A vent pipe is provided at the bottom and top of the adsorption submodule 15 respectively. An air intake pipe and an exhaust pipe are provided at the bottom end of the bottom vent pipe, and an air intake valve 11 and an exhaust valve 12 are respectively arranged. An oxygen exhaust pipe and a regeneration pipe are provided at the top end of the top vent pipe, and an oxygen outlet valve 13 and a regeneration valve 14 are respectively arranged. That is, the air intake pipe, the exhaust pipe, the oxygen exhaust pipe and the regeneration pipe are all arranged symmetrically from top to bottom. The adsorption submodule 15 is connected to the blast main pipe 104 through the vent pipe and the air intake pipe at the bottom. The air inlet end of the blast main pipe 104 is connected to the blast pipeline 101. A regulating valve 604 is provided on the blast main pipe 104. The adsorption submodule 15 is also connected through the bottom vent pipe, the exhaust pipe, and the exhaust main pipe. The end of the exhaust main pipe is provided with an exhaust check valve 17 and is connected to the exhaust pipe 102. The adsorption submodule 15 is connected to the oxygen outlet main pipe 105 through the top vent pipe and the oxygen exhaust pipe. The end of the oxygen outlet main pipe 105 is connected to the oxygen enrichment pipe 103; the adsorption submodule 15 is also connected to the regeneration main pipe 106 through the top vent pipe and the regeneration pipe. The end of the regeneration main pipe 106 is provided with a regeneration check valve 16 and is connected to the oxygen enrichment pipe 103. That is, the blast main pipe 104 and the exhaust main pipe, the oxygen outlet main pipe 105 and the regeneration main pipe 106 are respectively arranged in parallel.

[0055] In order to realize the automatic switching control during the operation of the three adsorption submodules 15, the control valves 602-605, the intake valve 11, the exhaust valve 12, the oxygen outlet valve 13, the regeneration valve 14, the regeneration check valve 16, and the exhaust check valve 17 can be selected as hydraulic valves, pneumatic valves, or solenoid valves, and are respectively connected to the automatic control device 100 through the actuator 300. Among them, the automatic control device 100 is a DDC or PLC controller, which is respectively connected to the sensor 200 and the valve actuator 300 to realize the automatic control of the system operation. Among them, the regeneration check valve 16 and the exhaust check valve 17 can also be mechanical valves.

[0056] Each regulating valve is used to control or shut off the airflow; the blower 3 is a high-efficiency blower, and can adopt mature products on the market such as magnetic levitation or air suspension blower. The vacuum pump 7 preferably uses mature magnetic levitation vacuum pumps, vortex vacuum pumps or air suspension vacuum pumps on the market. The cooler 4 can adopt mature water-cooled or air-cooled heat exchangers on the market.

[0057] In the actual working condition of the present invention, the adsorption submodule 15 is composed of a plurality of oxygen adsorption tubes, such as three in the figure. The specifications of the oxygen adsorption tubes are: the total axial length is 700 mm, the inner diameter of the end is 200 mm, and the internal geometric volume is 0.023 m 3 Around, and must be less than 0.025m 3 (According to standard specifications, it is a non-pressure vessel); assuming that a standard adsorption skid-mounted module 5 is composed of three adsorption sub-modules 15, and each adsorption sub-module 15 is equipped with four oxygen-generating adsorption tubes, a standard adsorption skid-mounted module 5 can produce about 250Nm3 / h of oxygen with a concentration of 90%.

[0058] Part 2 System Operation Method Description

[0059] 1. The air first passes through the air filter 2 to filter dust and remove water to ensure the purity of the air and avoid clogging the adsorbent. Then, the blower 3 is operated to pressurize the filtered air and transport it to the blast pipeline 101, and then it is cooled to an appropriate temperature (35-45°C) by the cooler 4, and is supplied as a pressurized raw material to the subsequent adsorption skid-mounted module 5 for the vacuum pressure swing adsorption oxygen production process.

[0060] In the adsorption skid-mounted module 5, after one of the air inlet valves 11 is opened, air is blown into the corresponding first adsorption submodule A15. At this time, the corresponding exhaust valve 12 is closed, and the oxygen adsorption tube is filled with adsorbent, wherein water, carbon dioxide, and a small amount of other gas components are first adsorbed by the activated alumina loaded at the bottom at the inlet, and then nitrogen is adsorbed by the zeolite molecular sieve, while oxygen and other non-adsorbed components are discharged from the top outlet as product gas into the oxygen exhaust pipe to obtain an oxygen-rich gas with a concentration of about 90%; then it flows out through the oxygen outlet valve 13, the oxygen outlet main pipe 105 and the oxygen-rich pipeline 103 into the oxygen balance tank 9 for buffering and pressure stabilization, and flows into the oxygen storage tank 10 for storage through the regulating valve 602.

[0061] 2. An example of switching the three first adsorption submodules A15, B15 and C15 in parallel:

[0062] like Figure 3 As shown, it is assumed that the first adsorption submodule A15 is in the stage of waiting for regeneration (desorption stage) after completing adsorption, the second adsorption submodule B15 is in the operation stage of intake adsorption and oxygen production (adsorption stage), and the third adsorption submodule C15 is in the stage of waiting for commissioning (pressurization stage) after vacuum desorption and regeneration.

[0063] First, the valve is switched to connect the regeneration pipe corresponding to the first adsorption submodule A15, the regeneration main pipe 106 and the regeneration pipe corresponding to the third adsorption submodule C15, so that the first adsorption submodule A15 and the third adsorption submodule C15 at a lower pressure are evenly pressure-dropped. This process is intended to recover the oxygen enriched in the first adsorption submodule A15, transfer it to the third adsorption submodule C15, and increase the pressure of the third adsorption submodule C15.

[0064] Then, the vacuum pump 7 is used to quickly extract the remaining gas in the first adsorption submodule A15, and the exhaust gas is discharged through the exhaust pipe, the exhaust gas main pipe, and the exhaust gas pipeline 102. The vacuum environment formed by the vacuum pump 7 helps to desorb impurities on the adsorbent and discharge impurities such as exhaust gas in the adsorption pipe. The muffler 8 is used to reduce the noise pollution generated by the exhaust gas. While the first adsorption submodule A15 is being vacuumed and desorbed, the adsorption and oxygen production stage of the second adsorption submodule B15 is nearly completed and is ready to enter the desorption regeneration process.

[0065] Stop the adsorption and oxygen production operation of the second adsorption submodule B15, connect the regeneration pipe corresponding to the second adsorption submodule B15, the regeneration main pipe 106 and the regeneration pipe corresponding to the third adsorption submodule C15, so that the second adsorption submodule B15 is connected with the third adsorption submodule C15 (which has been pressurized and part of the oxygen has been recovered) to equalize the pressure drop. Further recover the oxygen-rich gas in the second adsorption submodule B15, and continue to increase the pressure of the third adsorption submodule C15. Use valve switching to switch the third adsorption submodule C15 to the operation stage of intake air adsorption and oxygen production.

[0066] At this time, the third adsorption submodule C15 is in the operation stage of intake air adsorption and oxygen production (adsorption stage), the second adsorption submodule B15 is in the waiting regeneration stage after completion of adsorption (desorption stage), and the first adsorption submodule A15 is in the waiting operation stage after desorption and regeneration (pressurization stage);

[0067] The valves are controlled by automatic control equipment, and the operation contents of steps (1) to (4) are repeatedly executed according to the set program. During the switching operation of each adsorption submodule, the time node of the switching operation is confirmed according to the preset control threshold value and the real-time pressure value and temperature value in the pipeline obtained by each sensor.

[0068] For an oxygen production system with only two adsorption submodules, while one submodule is in the adsorption oxygen production operation state, the other submodule is in desorption and regeneration treatment, and the two serve as backup for each other and switch cyclically; when switching operation, the two adsorption submodules are first connected to equalize the pressure drop, and then the operation of commissioning and regeneration is performed respectively;

[0069] For an oxygen production system with more than three adsorption submodules, the operations are performed in accordance with the contents of steps (1) to (4), and more submodules are in the waiting stage for commissioning.

[0070] The above adsorption, waiting for regeneration and regeneration process can realize accurate control and optimization of each electronically controlled valve through the cooperation of the automatic control device 100, the sensor 200 and the actuator 300, so as to realize efficient and continuous oxygen production. Relying on existing control algorithms and other technologies, the flexible switching operation of each adsorption submodule in the system can be realized, which can significantly improve the high precision and responsiveness of system control, and further improve the redundancy and reliability of the system.

[0071] 3. Optional operation scheme

[0072] By adding an aftercooler (a well-known heat exchanger, air-cooled or water-cooled mode) after the blower, the adsorption capacity and efficiency of the adsorbent for gas components during the separation process of the vacuum pressure swing adsorption gas can be improved, and the risks caused by excessively high blast temperature can be effectively prevented.

[0073] The present invention can utilize 2 to 4 adsorption submodules 15 to replace the adsorption tower in the traditional VPSA oxygen production system, and each corresponding adsorption submodule 15 is composed of a number of oxygen-producing adsorption tubes. In actual working conditions, each adsorption submodule 15 can be configured with the number of oxygen-producing adsorption tubes according to the actual gas volume requirements. In this example scheme, it is composed of 4 oxygen-producing adsorption tubes, and there are 12 oxygen-producing adsorption tubes in a single set of standard adsorption skid-mounted modules 5. The standard adsorption skid-mounted module 5 achieves the high efficiency of personalized production through standardized design, factory assembly, and large-scale customization, while providing a wider flow adjustment range. In addition, the design of multiple oxygen-producing adsorption tubes can fully stabilize the pressure fluctuations during the oxygen production process, significantly improving the reliability, stability and efficiency of the VPSA oxygen production process. The standard adsorption submodule 15 composed of these oxygen-producing adsorption tubes adopts a pressure-free vessel design, which further enhances the safety of the oxygen production system;

[0074] When multiple groups of adsorption skid-mounted modules 5 are connected in parallel to produce oxygen, only one set of blower 3 and vacuum pump 7 can be configured, or one can be used and the other can be used as a backup. No additional equipment is required in the system, thereby simplifying the oxygen production process and significantly reducing the energy consumption in the VPSA oxygen production process.

[0075] Part 3 Oxygen Adsorption Tube

[0076] 1. The oxygen production adsorption tube of the present invention can be selected from the following Figure 5 The axial type oxygen generating adsorption tube is shown.

[0077] The structure of the axial oxygen adsorption tube is similar to that of the adsorption tower. It usually adopts the method of air intake from the bottom, and the dried gas is transmitted along the axial direction of the adsorption tube. During the transmission process, the molecular sieve is used to adsorb and separate specific components. However, since the gas transmission process needs to pass through the entire molecular sieve filling path, there are higher requirements for the gas intake pressure, resulting in higher energy consumption of the blower or compressor. In addition, since the adsorption amount of the molecular sieve is uneven in the axial direction, the front adsorption is more and saturated earlier, while the back adsorption is less and saturated later. This unbalanced adsorption effect requires longer time and more regeneration gas consumption during regeneration to ensure that the adsorbent with the most adsorption can be fully desorbed, which will further reduce the adsorption efficiency and increase energy consumption.

[0078] 2. In view of the technical deficiencies of the axial oxygen production adsorption tube, the present invention also provides Figure 6-12 The innovative design of the radial oxygen-generating adsorption tube shown.

[0079] (1) Product structure description

[0080] The radial oxygen production adsorption tube comprises a tube body 21 , a drying structure and a molecular sieve structure, and an inlet end cover 24 and an outlet end cover 34 respectively located at two ends of the tube body 21 .

[0081] The two ends of the tube body 21 are respectively provided with a tube body inlet section 22 and a tube body outlet section 23, and the middle of the outer end surfaces of both are provided with concentric through holes, and the three are connected by welding. The inner diameter of the tube body inlet section 22 and the tube body outlet section 23 are the same and are larger than the tube body 21 (such as Figure 7 The drying structure includes an inner clip 3602 adaptively embedded in the inner wall of the tube inlet section 22, an outer clip 3601 embedded in the inner wall of the through hole of the tube inlet section 22, and a drying chamber 36 formed between the outer clip 3601 and the inner clip 3602. The outer clip 3601 and the inner clip 3602 are both made of rigid breathable materials (such as rigid materials with breathable mesh holes).

[0082] The molecular sieve structure includes an inner cylinder 30 and an outer cylinder 28 which are concentrically nested and fixed to the inner end surface of the outlet section 23 of the tube body. Both the inner cylinder 30 and the outer cylinder 28 are made of rigid breathable materials. The outlet section of the inner cylinder 30 is fitted and connected to the inner wall surface of the through hole in the middle of the outlet section 23 of the tube body, and the outlet section of the inner cylinder 30 is located protruding from the outer end surface of the outlet section 23 of the tube body. A colloid seal ring 33 is provided on the outer wall surface of the protruding part of the outlet section of the inner cylinder 30. An oxygen-rich chamber 31 is formed inside the inner cylinder 30, an adsorption chamber 29 is formed between the inner cylinder 30 and the outer cylinder 28 for loading adsorbent, and a gas delivery chamber 32 is formed between the outer cylinder 28 and the inner wall surface of the tube body 21. A diverter block 41 is provided at the inner bottom end of the inner cylinder 30 and the outer cylinder 28. The diverter block 41 is a conical structure with a small lower end and a large upper end, and its upper end diameter is the same as the outer diameter of the outer cylinder 28.

[0083] A vent hole is provided in the center of the inlet end cover 24 and the outlet end cover 34. The inner wall of the vent hole is provided with a thread for connecting an external pipe joint with matching threads to achieve a quick connection. The inlet end cover 24 and the outlet end cover 34 have the same structure and size. Two desiccant feed ports 601 and adsorbent feed ports 2701 are symmetrically provided on the inlet end cover 24 and the outlet end cover 34, respectively. A desiccant inlet plug 2602 and an adsorbent inlet plug 2702 are installed on the desiccant feed port 2601 and the adsorbent feed port 2701, respectively.

[0084] A circular inner countersunk hole 39 is provided at the center of the inner end surface of the inlet end cover 24 and the outlet end cover 34. The inner side end surfaces of the inlet end cover 24 and the outlet end cover 34 surrounding the inner countersunk hole 39 are respectively installed in contact with the end surfaces of the tube body inlet section 22 and the tube body outlet section 23. The inner end surfaces of the inlet end cover 24 and the outlet end cover 34 are provided with a concentrically arranged annular outer countersunk hole 40 and an annular groove, and a sealing ring 38 is provided in the annular groove. The installation position of the outer countersunk hole 40 corresponds to the desiccant inlet plug 2602 and the adsorbent inlet plug 2702, and its width is slightly larger than the diameter of the two plugs; so that the protruding part of the plug can fall into the outer countersunk hole after installation, so as to avoid the plug being squeezed into the hole and unable to be taken out when the reagent is replaced next time.

[0085] On the end faces of the pipe body inlet section 22 and the pipe body outlet section 23, the same number of sunken screw holes 25 are evenly arranged in the circumferential direction, and in this embodiment, there are 4 screw holes. On the end faces of the inlet end cover 24 and the outlet end cover 34, the same number of connection holes 37 are correspondingly arranged. By passing a plurality of bolts 35 through the connection holes 37 and installing them in the screw holes 25, the inlet end cover 24 and the outlet end cover 34 can be fixed to the end faces of the pipe body inlet section 22 and the pipe body outlet section 23 respectively. As a preferred solution, the overall structure of the inlet end cover 24 and the outlet end cover 34 has a "J"-shaped transverse cross section, and the connection holes 37 thereof are arranged at a relatively low circumferential outer edge, and the heads of the bolts 35 after installation are not higher than the outermost surfaces of the inlet end cover 24 and the outlet end cover 34.

[0086] For example, in this embodiment, the total axial length of the tube body 21, the tube body inlet section 22, the tube body outlet section 23, the inlet end cover 24 and the outlet end cover 34 after installation is 700 mm, the inner diameter of the inlet end cover 24 or the outlet end cover 34 is 200 mm, and the internal geometric volume of the radial oxygen production adsorption tube is 0.023 m 3 About and less than 0.025m 3 According to national standards, it is a non-pressure vessel.

[0087] (2) Product assembly method

[0088] Step 1: The inner cylinder 30 and the outer cylinder 28 are fixed to the inner end surface of the pipe body outlet section 23 respectively, and the protruding part of the outlet section of the inner cylinder 30 is exposed outside the outer end surface of the pipe body outlet section 23; a colloid sealing ring 33 is provided outside the protruding part, and the colloid sealing ring 33 is coated around the outside of the sealing connection section with a viscous colloid, and an annular sealing ring is formed after solidification.

[0089] Step 2: Fix the diverter block 41 to the inner bottom ends of the inner tube 30 and the outer tube 28; install the outer clip 3601 and the inner clip 3602 on the inner wall of the tube inlet section 22 and the inner wall of the through hole of the tube inlet section 22 respectively;

[0090] Step 3: Install the pipe inlet section 22 and the pipe outlet section 23 at both ends of the pipe body 21 by welding;

[0091] Step 4: Fill the adsorbent into the adsorption bin 29 through the adsorbent feed port 2701, and after filling, install the adsorbent inlet plug 2702 into the adsorbent feed port 2701; fill the desiccant into the drying bin 36 through the desiccant feed port 2601, and after filling, install the desiccant inlet plug 2602 into the desiccant feed port 2601;

[0092] Step 5: The inlet end cover 24 and the outlet end cover 34 are fixedly mounted on the outer end surfaces of the pipe body inlet section 22 and the pipe body outlet section 23 respectively by means of bolts 35 .

[0093] (3) How to use the product

[0094] The threaded external pipe joints are respectively installed in the vent holes of the inlet end cap 24 and the outlet end cap 34 to realize the connection between the radial oxygen adsorption pipe and the blast gas pipeline and the oxygen-enriched gas pipeline; in use, multiple radial oxygen adsorption pipe assemblies can be operated in parallel according to the actual working conditions to realize the quick regulation of gas flow. As a preference, sensors and other equipment can be connected to the pipeline to realize online maintenance.

[0095] The pipeline is connected by threaded connection, which can not only achieve quick connection, but also improve the connection tightness between pipelines or between pipelines and vents. Compared with the traditional adsorption tower, the radial oxygen adsorption tube has a smaller overall volume and mass, which makes its disassembly, assembly and maintenance in use more convenient.

[0096] After the connection is completed, the blower air is introduced into the inlet end cover 24 and the pipe inlet section 22 through the pipeline. In the pipe inlet section 22, the blast gas is first dried axially by the desiccant to remove moisture. The dried blast gas flows evenly into the gas delivery cavity 32 through the diverter block 41, and radially passes through the adsorbent in the adsorption bin 29 for adsorption. The adsorption principle is that the nitrogen in the blast gas will be adsorbed by the adsorbent (such as molecular sieve), while other components (such as oxygen) will directly enter the oxygen-enriched chamber 31 after passing through the adsorbent to obtain oxygen-enriched gas (concentration is about 90%). Since the adsorbent has different adsorption capacities for different gas components, the separation of gas mixtures can be achieved. In the radial adsorption process, the contact area between the gas and the annular adsorbent is larger, and the adsorption efficiency is higher than that of the full axial adsorption tower used in the traditional technology. The obtained oxygen-enriched gas enters the oxygen-enriched chamber 31 and flows to the outlet end cover 34, and finally flows out through the vent hole in the center of the outlet end cover 34.

[0097] For example, among the several adsorbents commonly used in pressure swing adsorption gas separation devices, activated alumina is a solid with a strong affinity for water, generally prepared by thermal dehydration or thermal activation of aluminum trihydrate or gibbsite, and is mainly used for gas drying. Zeolite molecular sieve (Ga molecular sieve) adsorbent is a crystalline metasilicate containing alkaline earth elements. It is a highly polar adsorbent with a very consistent pore structure and extremely strong adsorption selectivity. Lithium-based molecular sieves replace Ga with more polar Li ions, making the adsorption capacity of the molecular sieve larger. During use, users can select the type of adsorbent according to their needs.

[0098] When the adsorbent reaches saturation, desorption is required to restore the adsorption capacity. At this time, the pressure in the radial oxygen adsorption tube can be reduced by discharging the gas in the tube or using a vacuum pump to extract the gas in the tube, so that the adsorbent releases the adsorbed gas components, and the released gas components enter the gas delivery cavity 32 and flow out through the vent holes of the inlet end cover 24, thereby achieving desorption. The above is the conventional operation of pressure swing adsorption, so it will not be repeated here; at the same time, the radial oxygen adsorption tube is also suitable for the application scenario of vacuum pressure swing adsorption.

[0099] (4) Relative technical advantages of radial oxygen adsorption tubes:

[0100] a. In the Chinese national standard GB150-2011 "Pressure Vessels", for fixed pressure vessels, the volume should be greater than or equal to 0.025 cubic meters (V ≥ 0.025m 3 ), radial oxygen adsorption tubes have a small product volume (the internal geometric volume of radial oxygen adsorption tubes can be as small as 0.023m 3 About); Since the geometric volume of the product is smaller than the pressure vessel volume specified in the national standard, it is safer and more reliable in use. At the same time, sensors and other equipment can be connected to the pipeline for online maintenance; and the radial oxygen adsorption tube is also easy to assemble and not easy to loosen during use, which significantly reduces the processing and maintenance costs.

[0101] b. During the use of the product, the number of radial oxygen-generating adsorption tubes can be increased or decreased according to actual working conditions, which can quickly adjust the flow rate of oxygen-rich gas and significantly broaden its adjustment range, thereby achieving more accurate and flexible flow control. Figure 1-3 As shown in the figure, multiple radial oxygen adsorption tubes are installed in parallel, and the oxygen-rich gas produced is connected to an external pipe for output, and can be directly used by users.

[0102] c. The radial oxygen adsorption tube adopts the process of axial air intake drying and radial adsorption gas outlet. In radial adsorption, the contact area between the gas and the annular adsorbent is larger, and the adsorption efficiency is higher than that of the traditional full-axial adsorption tower.

Claims

1. A method for achieving low-energy oxygen production using a tower-less VPSA oxygen production system, characterized in that: The method is implemented based on the following tower-less VPSA oxygen production system; The system comprises an air filter, a blower, a cooler and an adsorption skid-mounted module which are sequentially arranged on the blast pipeline; the adsorption skid-mounted module comprises more than two adsorption submodules which are arranged in parallel and have the same structure, an air intake pipe and an exhaust pipe are arranged at the bottom of each adsorption submodule, the air intake pipe is connected to the blast pipeline through the blast main pipe, and the exhaust pipe is connected to the exhaust pipeline through the exhaust main pipe; an oxygen exhaust pipe and a regeneration pipe are arranged at the top of each adsorption submodule, the oxygen exhaust pipe is connected to the oxygen-enriched pipeline through the oxygen outlet main pipe, and the regeneration pipe is connected to the oxygen-enriched pipeline through the regeneration main pipe; valves are respectively arranged on each pipeline, and an exhaust check valve is arranged at the end of the exhaust main pipe, and a regeneration check valve is arranged at the end of the regeneration main pipe; the oxygen-enriched pipeline is sequentially connected to an oxygen balance tank and an oxygen storage tank, and valves are respectively arranged at the inlet and outlet of the two tanks; the exhaust pipeline is sequentially connected to a vacuum pump and a muffler; the adsorption submodule comprises at least one oxygen-generating adsorption tube, and if there are multiple oxygen-generating adsorption tubes, they are combined and connected in parallel; the oxygen-generating adsorption tube is a radial oxygen-generating adsorption tube; The valves on each pipeline are any one of hydraulic valves and pneumatic valves, and the actuators of each electronically controlled regulating valve are connected to the automatic control device through cables; each pipeline is provided with a pressure sensor and a temperature sensor, which are connected to the automatic control device through signal lines; the automatic control device is a DDC controller or a PLC controller; The two ends of the radial oxygen production adsorption tube are respectively fixedly connected to the tube inlet section and the tube outlet section by welding, and the three together form an adsorption tube body with an internal cavity; A central through hole is provided on the end surface of the inlet section and the outlet section of the pipe body respectively; an inlet end cover and an outlet end cover are provided opposite to the end surfaces of the two and fixed by bolt connection; a vent hole is provided in the center of the inlet end cover and the outlet end cover; An inner clamp and an outer clamp are fixedly arranged on the inner side of the end face of the inlet section of the tube body, and a closed drying chamber is formed between the two to be filled with desiccant; two through holes connected to the drying chamber are arranged on the end face of the inlet section of the tube body, and plugs are arranged in the through holes; An outer cylinder and an inner cylinder are concentrically nested and installed on the inner side of the end face of the outlet section of the pipe body, a gas transmission cavity is formed between the outer cylinder and the pipe body, an adsorption chamber is formed between the outer cylinder and the inner cylinder, the inner cavity of the inner cylinder serves as an oxygen-enriched chamber and is connected to the central through hole on the end face of the outlet section of the pipe body and the vent hole of the outlet end cover; the non-installed ends of the outer cylinder and the inner cylinder are close to the inlet section of the pipe body and are blocked with a diverter block, so that the adsorption chamber becomes a closed structure for filling the adsorbent; two through holes connected to the adsorption chamber are provided on the end face of the outlet section of the pipe body, and plugs are provided in the through holes; The inner and outer clips, the outer tube and the inner tube are all made of rigid breathable materials; The method for producing oxygen specifically comprises: (1) Take the oxygen production system as an example, which is provided with three adsorption submodules, namely the first adsorption submodule, the second adsorption submodule and the third adsorption submodule, and is switched in parallel; it is assumed that the first adsorption submodule is in the waiting regeneration stage after the adsorption is completed, the second adsorption submodule is in the operation stage of intake adsorption and oxygen production, and the third adsorption submodule is in the waiting operation stage after desorption and regeneration; (2) connecting the first adsorption submodule with the third adsorption submodule at a relatively low pressure to equalize the pressure drop, recovering the oxygen enriched in the first adsorption submodule and transferring it to the third adsorption submodule, while increasing the pressure of the third adsorption submodule; (3) Using a vacuum pump to extract the remaining gas in the first adsorption submodule, and discharge the waste gas through the exhaust pipe and the waste gas pipeline; while the first adsorption submodule is being vacuumed and desorbed, the adsorption and oxygen production phase of the second adsorption submodule is nearly completed and is ready to enter the desorption and regeneration process; (4) Stop the oxygen production operation of the second adsorption submodule, and perform a second pressure drop operation on it and the third adsorption submodule that has been pressurized and recovered a portion of the oxygen, further recover and transfer the oxygen-rich gas in the second adsorption submodule, and continue to increase the pressure of the third adsorption submodule; after the third adsorption submodule receives the oxygen-rich gas from the first adsorption submodule and the second adsorption submodule respectively, switch it to the operation stage of air intake adsorption oxygen production; At this time, the third adsorption submodule is in the operation stage of air intake adsorption and oxygen production, the second adsorption submodule is in the stage of waiting for regeneration after completing adsorption, and the first adsorption submodule is in the stage of waiting for operation after desorption and regeneration; (5) Using the automatic control equipment to control each valve, repeating the operation contents of steps (1) to (4) according to the set program; during the switching operation of each adsorption submodule, the time node of the switching operation is confirmed according to the preset control threshold value and the real-time pressure value and temperature value in the pipeline obtained by each sensor; For an oxygen production system with more than three adsorption submodules, the operations are performed in accordance with the contents of steps (1) to (4), and more submodules are in the waiting stage for commissioning.

2. The method according to claim 1, characterized in that The specifications of a single oxygen production adsorption tube in the adsorption submodule are: total axial length 700 mm, end inner diameter 200 mm, and internal geometric volume less than 0.025 m³.

3. The method according to claim 1, characterized in that: The inner diameters of the tube inlet section and the tube outlet section are the same and both are larger than the inner diameter of the tube body; the structures and sizes of the inlet end cover and the outlet end cover are the same; the diverter block is a conical structure with a larger top and a smaller bottom, and the diameter of its upper end surface is the same as the outer diameter of the outer cylinder.

4. The method according to claim 1, characterized in that: The outlet section of the inner cylinder is tightly fitted with the inner wall surface of the central through hole of the end face of the tube body outlet section to achieve fixed installation, and the inner cylinder outlet section protrudes from the outer surface of the end face, and an annular colloid sealing ring is provided on the outer edge of the protruding part of the inner cylinder.

5. The method according to claim 1, characterized in that The inner wall surfaces of the vent holes of the inlet end cover and the outlet end cover are both provided with threads; inner countersunk holes surrounding the central vent hole are provided on the inner sides of the inlet end cover and the outlet end cover, and the two are installed with their inner countersunk holes corresponding to the central through holes on the end surfaces of the inlet section and the outlet section of the pipe body respectively.

6. The method according to claim 1, characterized in that The inner end faces of the inlet end cover and the outlet end cover are provided with concentrically arranged outer countersunk holes and annular grooves, and a sealing ring is provided in the annular groove; the installation position of the outer countersunk hole corresponds to the plugs on the end faces of the inlet section and the outlet section of the pipe body, and the width of the outer countersunk hole is slightly larger than the diameter of the plug, so that the protruding part of the plug can fall into the outer countersunk hole after installation.

7. The method according to claim 1, characterized in that The end faces of the pipe body inlet section and the pipe body outlet section are provided with the same number of sunken screw holes, and the inlet end cover and the outlet end cover are correspondingly provided with the same number of connecting holes, and a plurality of bolts pass through the connecting holes and are installed in the screw holes, respectively fixing the inlet end cover and the outlet end cover on the end faces of the pipe body inlet section and the pipe body outlet section.

8. The method according to claim 7, characterized in that The inlet end cover and the outlet end cover have a "J"-shaped transverse cross section, and the heads of the bolts after installation are not higher than the outermost surfaces of the inlet end cover and the outlet end cover.

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