Method and apparatus for drying oxygen

Abstract

The application provides a method and device for drying oxygen, which circulates the oxygen to be dried through at least one dryer to remove water, regenerate the drying agent and cool the drying agent, and obtains purified oxygen or regenerated purified oxygen by removing water, heats the purified oxygen by heat exchange with regenerated oxygen in the regeneration of the drying agent, and circulates the regenerated oxygen and the cooling oxygen in the regeneration of the drying agent and the cooling of the drying agent after being separated by liquid distribution. The method for drying oxygen provided by the application adopts a multi-dryer sequential control process, and each dryer is sequentially subjected to adsorption drying, drying agent regeneration and drying agent cooling, and the water content of the oxygen product is not more than 1 ppmv. The method not only has a simple process and no oxygen emptying, but also maximizes the use of oxygen resources, and avoids the simultaneous occurrence of high temperature and impact working conditions when a valve is suddenly opened in a high-purity oxygen environment, thereby essentially improving the safety of the oxygen drying device.

Description

Technical Field

[0001] This invention relates to the field of oxygen drying technology, specifically to a method and apparatus for oxygen drying. Background Technology

[0002] Oxygen is widely used in petrochemical, coal chemical, precision electronics, and biopharmaceutical industries. The purity of oxygen directly determines the number of downstream applications. Conventional oxygen production processes include: PSA (Pressure Separation and Aeration), membrane separation, cryogenic distillation, and high-temperature alkaline molten salt catalysis. Among these, cryogenic distillation is suitable for large-scale production, is a mature process, and produces high-purity products, simultaneously yielding both liquid and gaseous oxygen. However, due to its high investment cost, it is not suitable for applications with low oxygen demand. The other three oxygen production processes lag significantly behind cryogenic distillation in terms of energy consumption, purity, and technological maturity.

[0003] Industrial oxygen can be obtained from air separation or produced through water electrolysis. Generally, water electrolysis yields both hydrogen and oxygen, with hydrogen as the primary product and oxygen as a byproduct or directly released into the atmosphere. The oxygen produced by water electrolysis is highly pure (over 98.5% v) and contains trace amounts of water, hydrogen, and nitrogen. This technology allows for oxygen production on a moderate scale, overcoming the limitations of cryogenic distillation methods for small to medium scales. In recent years, with the large-scale promotion of renewable energy hydrogen production projects, the byproduct oxygen urgently needs treatment for downstream applications. However, conventional water electrolysis for oxygen purification faces challenges in meeting required standards and long-term operational requirements due to issues with impurity content, material selection, and program control. This has become a technological bottleneck in the production of green oxygen through water electrolysis.

[0004] In existing technologies, most of the oxygen produced during water electrolysis for hydrogen production is directly released into the atmosphere, with little attention paid to its drying and purification. Currently, oxygen drying typically employs adsorption processes and purified gas regeneration schemes. When deep dehydration is required, the operating temperature during regeneration must exceed 200°C, necessitating the switching of pure oxygen valves. This simultaneous occurrence of oxygen impact and temperatures exceeding 200°C increases the possibility of oxygen combustion and explosion, posing potential safety risks. Based on the inventor's extensive engineering experience and practical expertise gained through long-term research and development and engineering design in the field of water electrolysis for hydrogen production, and guided by market demand, this invention addresses the shortcomings of existing oxygen utilization technologies for water electrolysis-based hydrogen production. Through repeated research, experimentation, engineering design, and construction, a practically valuable oxygen drying method has been unexpectedly discovered.

[0005] Against this background, the present invention studies a method and apparatus for oxygen drying. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a method and apparatus for oxygen drying, thus solving the problems of high energy consumption and safety risks associated with current oxygen drying technologies.

[0007] To achieve the above objectives, the first aspect of the present invention provides a method for oxygen drying, the method comprising the following steps:

[0008] Drying and dehydration: The oxygen to be dried or the oxygen after separation is sent into at least one dryer, and the desiccant in the at least one dryer is used to adsorb the moisture in the oxygen to be dried or the oxygen after separation to obtain purified oxygen or regenerated purified oxygen.

[0009] Desiccant regeneration: A stream of purified oxygen is separated as purified oxygen #1. Purified oxygen #1 is then subjected to heat exchange and heating to obtain heated purified oxygen. The heated purified oxygen is then sent to at least one dryer to desorb the moisture adsorbed by the desiccant to obtain regenerated oxygen. The regenerated oxygen is then subjected to heat exchange and cooling to obtain separated oxygen #1.

[0010] Desiccant cooling: One stream of purified oxygen #1 is separated as purified oxygen #2. Purified oxygen #2 is cooled to obtain pre-cooled purified oxygen. The pre-cooled purified oxygen is sent into at least one dryer to reduce the bed temperature of the desiccant to obtain cooled oxygen. The cooled oxygen is then cooled and separated to obtain separated oxygen #2.

[0011] The purified oxygen and regenerated oxygen exchange heat to raise the temperature;

[0012] The oxygen after separation is either the oxygen after separation #1 or the oxygen after separation #2.

[0013] A second aspect of the present invention provides an oxygen drying apparatus, the apparatus comprising at least one dryer, an oxygen drying heat exchanger, an oxygen electric heater, a purge cooler, a regeneration gas cooler, and an oxygen separator.

[0014] One end of the at least one dryer is connected to the oxygen feed line to be dried, the oxygen feed line after liquid separation, and the regenerated cooling oxygen discharge line through their respective independent switching valves. The other end is connected to the purified oxygen discharge line, the regenerated purified oxygen discharge line, and the heated / pre-cooled purified oxygen feed line through their respective independent switching valves.

[0015] A branch of the purified oxygen outlet pipeline is connected to the refrigerant inlet of the oxygen drying heat exchanger as the No. 1 purified oxygen pipeline, and the refrigerant outlet of the oxygen drying heat exchanger is connected to the inlet of the oxygen electric heater.

[0016] A branch of the No. 1 purified oxygen pipeline is connected to the No. 2 purified oxygen pipeline and the heat medium inlet of the purge cooler. The outlet of the oxygen electric heater and the outlet of the purge cooler are connected to the heating / pre-cooling purified oxygen feed pipeline.

[0017] At least one dryer has a regenerated cooling oxygen outlet pipeline at its bottom, which is connected to the heat medium inlet of the oxygen drying heat exchanger. The heat medium outlet of the regenerated gas cooler is connected to the inlet of the oxygen separator. The gas phase outlet at the top of the oxygen separator is connected to the oxygen inlet pipeline after separation. A condensate outlet pipeline is provided at the bottom of the tank.

[0018] The effects of this invention are:

[0019] (1) The oxygen drying method proposed in this invention adopts a multi-dryer sequential control process. Each dryer sequentially undergoes adsorption drying to remove water, desiccant regeneration, and desiccant cooling, and the water content of the oxygen product is no more than 1 ppmv. In addition, the oxygen drying process disclosed in this invention is simple, with no oxygen venting, and the oxygen resources are maximized.

[0020] (2) The oxygen drying method and apparatus proposed in this invention detects the oxygen temperature at the outlet of the oxygen heater and uses program control to open the valve on the regeneration gas pipeline at the top of the regeneration dryer when the temperature rises to 100°C. This avoids the simultaneous occurrence of high temperature and impact conditions when the valve is suddenly opened in a high-purity oxygen environment, and fundamentally improves the safety of the oxygen drying apparatus.

[0021] (3) The oxygen drying method and apparatus proposed in this invention are equipped with independent temperature detectors on the heating / pre-cooling purified oxygen feed line and the oxygen electric heater outlet line. When the temperature of the heated purified oxygen exceeds 200°C and the valve on the regeneration gas line at the top of the dryer is not opened, the heated purified oxygen entering the dryer is lower than 200°C by injecting quench oxygen, thereby further reducing the high temperature and impact risk caused by the valve opening in a pure oxygen environment.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0023] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0024] Figure 1 This is a schematic diagram of the process flow of a specific embodiment of the oxygen drying method and apparatus proposed in this invention.

[0025] Figure 2 This is a schematic diagram of the process flow of another specific embodiment of the oxygen drying method and apparatus proposed in this invention.

[0026] Figure 3 This is a schematic diagram of the process flow of the third specific embodiment of the oxygen drying method and apparatus proposed in this invention.

[0027] Figure 4 This is a schematic diagram of the process flow of the fourth specific embodiment of the oxygen drying method and apparatus proposed in this invention.

[0028] Explanation of reference numerals in the attached figures:

[0029] 101—Dryer, 102—Oxygen drying heat exchanger, 103—Oxygen electric heater, 104—Purge cooler, 105—Regeneration gas cooler, 106—Oxygen separator;

[0030] S1—Oxygen to be dried, S2—Purified oxygen, S3—Chilled water supply, S4—Chilled water return, S5—Regenerated purified oxygen, S6—Purified oxygen #1, S7—Purified oxygen #2, S8—Pre-cooled purified oxygen, S9—Preheated purified oxygen, S10—Heated purified oxygen, S11—Pre-cooled purified oxygen / heated purified oxygen, S12—Oxygen after cooling, S13—Cooled oxygen, S14—Oxygen after separation, S15—Oxygen at the dryer outlet, S16—Quick-cooled oxygen.

[0031] XV1—1# switch valve, XV2—2# switch valve, XV3—3# switch valve, XV4—4# switch valve, XV5—5# switch valve, XV6—6# switch valve, XV7—7# switch valve, XV8—regenerated oxygen switch valve, XV9—quench oxygen switch valve. Detailed Implementation

[0032] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0033] In this disclosure, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its normal operating state, for example, as shown in the reference. Figure 1 In the drawing orientation, "inner" and "outer" refer to their relative to the outline of the device. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0034] This invention provides a method for oxygen drying, such as... Figure 1 As shown, the method includes the following steps:

[0035] Drying and dehydration: The oxygen S1 to be dried or the oxygen S14 after separation is sent into at least one dryer 101, and the desiccant in at least one dryer 101 is used to adsorb the moisture in the oxygen S1 to be dried or the oxygen S14 after separation to obtain purified oxygen S2 or regenerated purified oxygen S5.

[0036] Desiccant regeneration: A stream of purified oxygen S2 is separated as purified oxygen S6 #1. Purified oxygen S6 is then subjected to heat exchange and heating to obtain heated purified oxygen S10. Heated purified oxygen S10 is then sent to at least one dryer 101 to desorb the moisture adsorbed by the desiccant to obtain regenerated oxygen. The regenerated oxygen is then subjected to heat exchange and cooling to obtain separated oxygen #1.

[0037] Desiccant cooling: One stream of purified oxygen S6 is separated from 1# purified oxygen S6 to become purified oxygen S7 2#. Purified oxygen S7 2# is cooled to obtain pre-cooled purified oxygen S8. Pre-cooled purified oxygen S8 is sent into at least one dryer 101 to reduce the bed temperature of the desiccant to obtain cooled oxygen. The cooled oxygen is then cooled and separated to obtain 2# separated oxygen.

[0038] #1 Purified oxygen S6 exchanges heat with regenerated oxygen to raise the temperature;

[0039] Oxygen S14 after separation is either oxygen after separation #1 or oxygen after separation #2.

[0040] In this invention, a multi-dryer sequential control process is adopted. Each dryer sequentially undergoes adsorption drying to remove water, desiccant regeneration, and desiccant cooling, ensuring that the water content of the oxygen product is no more than 1 ppmv. Furthermore, the oxygen drying process disclosed in this invention is simple, involves no oxygen venting, and maximizes the utilization of oxygen resources.

[0041] Preferably, when the number of the at least one dryer 101 is greater than one, the dryers (101) are connected in parallel;

[0042] The drying and dehydration step also includes: detecting the moisture adsorption state of the desiccant in at least one dryer 101, and performing a desiccant regeneration step when the moisture adsorption of the desiccant reaches saturation.

[0043] The desiccant regeneration step also includes:

[0044] The temperature of the heated purified oxygen S10 is detected. When the temperature of the heated purified oxygen S10 is 100℃-200℃, the heated purified oxygen S10 is sent into at least one dryer 101 to desorb the moisture adsorbed by the desiccant. When the temperature of the heated purified oxygen S10 is greater than 200℃, quench oxygen S16 is injected into the heated purified oxygen S10 to reduce the temperature of the heated purified oxygen S10 to 100℃-200℃. Quench oxygen S16 is another stream separated from purified oxygen S2.

[0045] When one step is performed, the gas valves related to the other two steps are closed.

[0046] In this invention, by detecting the temperature of the purified oxygen S10 during heating, a programmable control method is used to open the valve on the regeneration gas pipeline at the top of the regenerator when the temperature rises to 100°C. This avoids the simultaneous occurrence of high temperature and impact conditions when the valve is suddenly opened in a high-purity oxygen environment, thereby fundamentally improving the safety of the oxygen drying device.

[0047] In this invention, when the temperature of the heated purified oxygen exceeds 200°C and the valve on the regeneration gas pipeline at the top of the dryer is not open, rapid cooling oxygen is injected to lower the temperature of the heated purified oxygen entering the dryer below 200°C, thereby further reducing the high temperature and impact risks caused by opening the valve in the pure oxygen environment.

[0048] According to a preferred embodiment of the present invention, the oxygen to be dried S1 and the separated oxygen S14 flow in the same direction in at least one dryer 101; preferably, they both enter from the bottom of at least one dryer 101.

[0049] The heated purified oxygen S10 and the pre-cooled purified oxygen S8 flow in the same direction in at least one dryer 101; preferably, they both enter from the top of at least one dryer 101.

[0050] The oxygen to be dried S1 and the heated and purified oxygen S10 flow in opposite directions in at least one dryer 101;

[0051] Purified oxygen S2 and regenerated purified oxygen S5 are extracted together as purified oxygen.

[0052] In the desiccant regeneration step, the regenerated oxygen is successively subjected to heat exchange and cooling, cooling and separation to obtain condensate No. 1;

[0053] In the desiccant cooling step, the oxygen is cooled down and separated to obtain condensate No. 2.

[0054] According to the present invention, the dryer (101) is at least two connected in parallel;

[0055] In the drying and dehydration step, the desiccant in each dryer adsorbs the moisture in one stream of oxygen to be dried S1 or one stream of separated oxygen S14 to obtain one stream of purified oxygen or one stream of regenerated purified oxygen. One stream of purified oxygen and all the remaining streams of purified oxygen obtained from the other dryers are merged into purified oxygen S2. One stream of regenerated purified oxygen and all the remaining streams of regenerated purified oxygen obtained from the other dryers are merged into regenerated purified oxygen S5.

[0056] In the desiccant regeneration step, a stream of heated purified oxygen is fed into each dryer to desorb the moisture adsorbed by the desiccant and obtain a stream of regenerated oxygen. This stream of regenerated oxygen is then combined with all the remaining streams of regenerated oxygen obtained from the other dryers to form regenerated oxygen.

[0057] In the desiccant cooling step, a stream of pre-cooled purified oxygen is fed into each dryer to lower the bed temperature of the desiccant, resulting in a stream of cooled oxygen. This stream of cooled oxygen merges with all the remaining streams of cooled oxygen obtained from the other dryers to form a single stream of cooled oxygen.

[0058] According to the present invention, the drying temperature of each dryer is 10-90°C, preferably 20-60°C, and the pressure is 0.1-5.0 MPa, preferably 0.5-3.2 MPa; the regeneration temperature is 150-300°C, preferably 210-260°C, and the pressure is 0.1-5.0 MPa, preferably 0.5-3.2 MPa; the cooling temperature is 7-50°C, preferably 7-35°C, and the pressure is 0.1-5.0 MPa, preferably 0.5-3.2 MPa.

[0059] The water content in the oxygen to be dried S1 is no more than 2.5 wt%; the water content in the purified oxygen S2 is no more than 1 ppmv.

[0060] The ratio of the amount of purified oxygen S6 to the amount of purified oxygen S2 is in the range of 10%-35%, preferably 15-25%;

[0061] The ratio of the amount of purified oxygen S7 to the amount of purified oxygen S2 is in the range of 10%-35%, preferably 15-25%;

[0062] At least one dryer 101 is selected from at least one of a fixed bed, a radial bed, and an axial-radial bed;

[0063] The desiccant is selected from at least one of activated alumina, silica gel, molecular sieve, anhydrous magnesium sulfate, activated carbon, anhydrous calcium chloride, quicklime, solid caustic soda, anhydrous copper sulfate, phosphorus pentoxide, and calcium sulfate, preferably from at least one of activated alumina, silica gel, molecular sieve, anhydrous magnesium sulfate, activated carbon, and anhydrous calcium chloride, and more preferably from at least one of activated alumina, silica gel, molecular sieve, and activated carbon.

[0064] The present invention also provides an apparatus for performing the above-described method, such as... Figure 1 As shown, the device includes at least one dryer 101, an oxygen drying heat exchanger 102, an oxygen electric heater 103, a purge cooler 104, a regeneration gas cooler 105, and an oxygen separator 106.

[0065] At least one dryer 101 is connected to the oxygen feed line to be dried, the oxygen feed line after liquid separation, and the regenerated cooling oxygen discharge line through its own independent switching valves at one end, and to the purified oxygen discharge line, the regenerated purified oxygen discharge line, and the heated / pre-cooled purified oxygen feed line through its own independent switching valves at the other end.

[0066] A branch of the purified oxygen outlet pipeline is connected to the refrigerant inlet of the oxygen drying heat exchanger 102 as the No. 1 purified oxygen pipeline. The refrigerant outlet of the oxygen drying heat exchanger 102 is connected to the inlet of the oxygen electric heater 103.

[0067] A branch of the No. 1 purified oxygen pipeline is connected to the No. 2 purified oxygen pipeline and the heat medium inlet of the purge cooler 104. The outlet of the oxygen electric heater 103 and the heat medium outlet of the purge cooler 104 are connected to the heating / pre-cooling purified oxygen feed pipeline.

[0068] At least one dryer 101 has a regenerated cooling oxygen outlet pipeline at its bottom, which is connected to the heat medium inlet of the oxygen drying heat exchanger 102. The heat medium outlet of the regenerated gas cooler 105 is connected to the feed inlet of the oxygen separator 106. The gas phase outlet at the top of the oxygen separator 106 is connected to the oxygen feed pipeline after separation, and a condensate outlet pipeline is provided at the bottom of the tank.

[0069] Preferably, at least two dryers (101) are connected in parallel;

[0070] One end of each dryer is connected to the oxygen feed line to be dried, the oxygen feed line after liquid separation, and the regenerated cooling oxygen discharge line via their respective independent switching valves. The other end is connected to the purified oxygen discharge line, the regenerated purified oxygen discharge line, and the heated / pre-cooled purified oxygen feed line via their respective independent switching valves.

[0071] A No. 7 switch valve XV7 is installed on the regenerated cooling oxygen outlet pipeline, a regenerated oxygen switch valve XV8 is installed on the refrigerant inlet pipeline of the oxygen drying heat exchanger 102, and a quench oxygen switch valve XV9 is installed on another optional branch pipeline from the purified oxygen outlet pipeline.

[0072] The heating / precooling purified oxygen feed line and the oxygen electric heater 103 outlet line are each equipped with their own independent temperature detectors.

[0073] At least one dryer 101 is filled with desiccant.

[0074] According to the present invention, the device further includes a controller, which is used to control the opening and closing states of the independent switching valves at both ends of each dryer, the #7 switching valve XV7, the regeneration oxygen switching valve XV8, and the quench oxygen switching valve XV9, based on the moisture adsorption state of the desiccant in each dryer and / or the temperature detected by the temperature detectors on the heating / pre-cooling purified oxygen feed line and the oxygen electric heater 103 outlet line, to achieve the drying and dehydration of the oxygen to be dried, the desiccant regeneration, and the desiccant cooling of each dryer;

[0075] The controller can be selected from either PLC or DCS, with PLC being the preferred choice.

[0076] According to a preferred embodiment of the present invention, the controller is used to control each dryer to perform drying and dehydration of the oxygen to be dried and desiccant regeneration, or to control each dryer to perform drying and dehydration of the oxygen to be dried and desiccant cooling, based on the moisture adsorption state of the desiccant in each dryer and / or the temperature detected by the temperature detectors on the heating / pre-cooling purified oxygen feed line and the oxygen electric heater 103 outlet line.

[0077] According to the present invention, at least one dryer 101 is selected from at least one of a fixed bed, a radial bed, and an axial-radial bed;

[0078] At least one dryer 101, oxygen electric heater 103, oxygen inlet and outlet pipelines and each switch valve are each independently selected from at least one of 304 / 304L, 316 / 316L, 321, 347 stainless steel, Monel alloy, nickel-based alloy.

[0079] The desiccant is selected from at least one of activated alumina, silica gel, molecular sieve, anhydrous magnesium sulfate, activated carbon, anhydrous calcium chloride, quicklime, solid caustic soda, anhydrous copper sulfate, phosphorus pentoxide, and calcium sulfate, preferably selected from at least one of activated alumina, silica gel, molecular sieve, anhydrous magnesium sulfate, activated carbon, and anhydrous calcium chloride, and more preferably selected from at least one of activated alumina, silica gel, molecular sieve, and activated carbon;

[0080] The refrigerant used in the purge cooler 104 and the regeneration gas cooler 105 is preferably 7°C chilled water.

[0081] The present invention will be described in more detail below through embodiments.

[0082] Example 1

[0083] like Figure 1As shown, this embodiment provides an oxygen drying apparatus, which includes three parallel dryers 101, an oxygen drying heat exchanger 102, an oxygen electric heater 103, a purge cooler 104, a regeneration gas cooler 105, and an oxygen separator 106.

[0084] The three parallel dryers 101 are connected to the oxygen feed line to be dried, the oxygen feed line after liquid separation, and the regenerated cooling oxygen discharge line at one end on the same side, respectively, and to the purified oxygen discharge line, the regenerated purified oxygen discharge line, and the heated / pre-cooled purified oxygen feed line at the other end, respectively.

[0085] A branch of the purified oxygen outlet pipeline is connected to the refrigerant inlet of the oxygen drying heat exchanger 102 as the No. 1 purified oxygen pipeline. The refrigerant outlet of the oxygen drying heat exchanger 102 is connected to the inlet of the oxygen electric heater 103.

[0086] A branch of the No. 1 purified oxygen pipeline is connected to the No. 2 purified oxygen pipeline and the heat medium inlet of the purge cooler 104. The outlet of the oxygen electric heater 103 and the heat medium outlet of the purge cooler 104 are connected to the heating / pre-cooling purified oxygen feed pipeline.

[0087] At least one dryer 101 has a regenerated cooling oxygen outlet pipeline at the bottom, which is connected to the heat medium inlet of the oxygen drying heat exchanger 102. The heat medium outlet of the regenerated gas cooler 105 is connected to the feed inlet of the oxygen separator 106. The gas phase outlet at the top of the oxygen separator 106 is connected to the oxygen feed pipeline after separation. A condensate outlet pipeline is provided at the bottom of the tank.

[0088] Each dryer has its own independent switching valve connecting one end to the oxygen feed line to be dried, the oxygen feed line after liquid separation, and the regenerated cooling oxygen discharge line, and the other end to the purified oxygen discharge line, the regenerated purified oxygen discharge line, and the heated / pre-cooled purified oxygen feed line, respectively.

[0089] A No. 7 switch valve XV7 is installed on the regenerated cooling oxygen outlet pipeline, and a regenerated oxygen switch valve XV8 is installed on the refrigerant inlet pipeline of the oxygen drying heat exchanger 102.

[0090] The heating / precooling purified oxygen feed line and the oxygen electric heater 103 outlet line are each equipped with their own independent temperature detectors.

[0091] Each dryer is filled with desiccant;

[0092] The device also includes a controller, which controls the opening and closing states of the independent switching valves at both ends of each dryer, the #7 switching valve XV7, and the regeneration oxygen switching valve XV8, based on the moisture adsorption state of the desiccant in each of the three parallel dryers 101 and / or the temperature detected by the temperature detectors on the heating / pre-cooling purified oxygen feed line and the oxygen electric heater 103 outlet line, to achieve drying and dehydration of the oxygen to be dried, desiccant regeneration, and desiccant cooling in each dryer.

[0093] The controller is a PLC;

[0094] The controller is used to control each dryer to perform drying and dehydration of the oxygen to be dried and desiccant regeneration, or to control each dryer to perform drying and dehydration of the oxygen to be dried and desiccant cooling, based on the desiccant moisture adsorption state in each of the three parallel dryers 101 and the temperature detected by the temperature detector (not shown) on the heating / pre-cooling purified oxygen feed line and the oxygen electric heater 103 outlet line.

[0095] The three parallel dryers 101 are fixed-bed dryers;

[0096] The three parallel dryers 101, the oxygen electric heater 103, the oxygen inlet and outlet pipelines, and all the switching valves are made of 304L stainless steel.

[0097] Desiccant: 13X molecular sieve.

[0098] like Figure 1 As shown, this embodiment provides a method for oxygen drying.

[0099] Dryers 101A, 101B, and 101C sequentially pass through the stages of drying and dehydration, desiccant regeneration, and desiccant cooling, thus achieving continuous operation of the drying device.

[0100] Drying and dehydration: The oxygen S1 to be dried is fed into the bottom inlet of dryer 101A. The moisture in the oxygen S1 is physically adsorbed by the desiccant, resulting in purified oxygen S2. At this time, valves XV1A and XV4A are open, while valves XV2A, XV3A, XV5A, and XV6A are closed. Dryer 101A is in operation until the moisture adsorption is saturated. Dryers 101B and 101C are in regeneration and standby states.

[0101] Desiccant Regeneration: After the desiccant in dryer 101B becomes saturated with moisture, it enters the regeneration stage. The inlet and outlet gas valves XV1B and XV4B of dryer 101B are closed. Purified oxygen S6 is drawn from purified oxygen S2, passes through oxygen drying heat exchanger 102 to obtain preheated purified oxygen S9, and is then heated by oxygen electric heater 103 to obtain heated purified oxygen S10, which enters dryer 101B through the top regeneration inlet. Valves XV6B and XV3B are opened. When the temperature of heated purified oxygen S10 reaches 150℃, valve XV6B is opened via program control. Under the action of heated purified oxygen S10, the desiccant absorbs moisture... The moisture is desorbed and enters the gas phase oxygen. After leaving the bottom of the dryer 101B as the outlet oxygen S15, it sequentially passes through the oxygen drying heat exchanger 102 and the regeneration gas cooler 105 to obtain cooled oxygen S12 and cooled oxygen S13. The cooled oxygen S13 is sent into the oxygen separator 106. The separated condensate is discharged from the bottom of the oxygen separator 106. The oxygen at the top of the oxygen separator 106 enters the next stage of regeneration completed dryer 101C. The XV2C and XV5C valves are opened, and the regenerated purified oxygen S5 and purified oxygen S2 are combined and sent out of the device until the regeneration is completed. The oxygen electric heater 103 and the inlet and outlet valves on the regeneration gas line are closed.

[0102] Desiccant Cooling: Purified oxygen S7 (No. 2) is drawn from purified oxygen S6 (No. 1). With valve XV8 closed, it passes through purge cooler 104 to obtain pre-cooled purified oxygen S8. This pre-cooled oxygen S8 enters dryer 101B through the top cooling inlet. Under the action of pre-cooled purified oxygen S8, the desiccant bed temperature is reduced. It then exits from the bottom of dryer 101B and sequentially passes through oxygen drying heat exchanger 102, valve XV7 open, and regeneration gas cooler 105 to obtain cooled oxygen S12 and cooled oxygen S13. Cooled oxygen S13 is sent to oxygen separator 106. The separated condensate is discharged from the bottom of oxygen separator 106. Oxygen from the top of oxygen separator 106 enters the next stage of regeneration in dryer 101C. Regenerated purified oxygen S5 and purified oxygen S2 are combined and sent out of the device until cooling is complete. Then, purified oxygen S7 (No. 2) and the inlet / outlet valves on the cooling gas line are closed. At this point, dryer 101B has completed complete regeneration and is ready for standby.

[0103] In this embodiment, the pre-cooled purified oxygen / heated purified oxygen S11 is heated purified oxygen S10 in the desiccant regeneration stage and pre-cooled purified oxygen S8 in the desiccant cooling stage; the chilled water supply S3 is 7°C chilled water; the purge cooler 104 and the regenerated gas cooler 105 share the chilled water supply S3 and chilled water return S4.

[0104] In this embodiment, the opening and closing status of each switching valve at this stage is shown in Table 1;

[0105] Each dryer proceeds to the next stage according to the programmed sequence. At this time, adsorption dryer 101A enters the regeneration state, regeneration dryer 101B enters the standby state, and standby dryer 101C enters the adsorption drying state. The three dryers 101 continue to perform the three steps of adsorption drying, adsorbent regeneration, and adsorbent cooling as described above, to achieve continuous regeneration of oxygen drying.

[0106] In this embodiment, the temperature of dryer 101A during normal drying is 35°C and the pressure is 1.5 MPa; the temperature of dryer 101B during regeneration is 250°C and the pressure is 1.5 MPa; the temperature of dryer 101B during cooling is 25°C and the pressure is 1.5 MPa; the water content in the oxygen to be dried S1 is no more than 1.0% (volume fraction); the water content in the purified oxygen is 0.5 ppmv. The ratio of purified oxygen S6 (1#) to purified oxygen S2 is 20%, and the ratio of purified oxygen S7 (2#) to purified oxygen S2 is 15%.

[0107] This embodiment achieves zero oxygen discharge and avoids high-temperature shock conditions by setting up three dryers and simultaneously detecting the temperature of the regenerated oxygen to open the valve on the regenerated gas pipeline, thereby improving the inherent safety of the device.

[0108] Table 1. On / off state of the valve

[0109]

[0110] Example 2

[0111] like Figure 2 As shown, this embodiment provides another apparatus and method for oxygen drying. The only difference between this embodiment and Embodiment 1 is that only two dryers are used; all other parameters are the same. This embodiment is suitable for situations where the oxygen to be dried has low moisture content, such as a water volume fraction of 0.2% and a water content of 0.5 ppmv in the purified oxygen.

[0112] Example 3

[0113] like Figure 3 As shown, this embodiment provides a third type of oxygen drying apparatus and method. Compared with Embodiment 1, the only difference is that four dryers are used; all other parameters are the same. This embodiment is suitable for conditions where the oxygen to be dried contains a high amount of moisture, such as a water volume fraction of 2.0% and a water content of 0.8 ppmv in the purified oxygen. In this embodiment, silica gel is used as the desiccant, and the dryers are of an axial-radial type. This embodiment uses four dryers, which can effectively handle the drying of oxygen with high moisture content and achieve continuous operation of the drying process.

[0114] Example 4

[0115] like Figure 4As shown, this embodiment provides a fourth type of oxygen drying apparatus and method. In this embodiment, three dryers are also used. The difference from Embodiment 1 is that a quench oxygen injection point S16 is provided on the pipeline between the oxygen electric heater 103 and the temperature detector (not shown). When the temperature of the heated purified oxygen S10 exceeds 200°C, and the inlet valve XV6 on the regeneration pipeline at the top of the dryer is closed, the inlet valve XV9 on the quench oxygen S16 is opened so that the temperature of the heated purified oxygen S10 does not exceed 200°C before the inlet valve XV6 on the regeneration pipeline at the top of the dryer can be opened. By injecting cold oxygen, high-temperature impact conditions are also avoided, improving the inherent safety of the apparatus.

[0116] The embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method of drying oxygen, characterized by, The method comprises the following steps: The method comprises the following steps: Drying and removing water: the oxygen to be dried (S1) or the separated oxygen (S14) is sent into at least one dryer (101), and the water in the oxygen to be dried (S1) or the separated oxygen (S14) is adsorbed by a drying agent in the at least one dryer (101) to obtain purified oxygen (S2) or regenerated purified oxygen (S5); Drying agent regeneration: the purified oxygen (S2) is divided into a 1# purified oxygen (S6), the 1# purified oxygen (S6) is sequentially heated and warmed by heat exchange to obtain warmed purified oxygen (S10), and the warmed purified oxygen (S10) is sent into the at least one dryer (101) to desorb the water adsorbed by the drying agent to obtain regenerated oxygen, and the regenerated oxygen is sequentially cooled and cooled by heat exchange to obtain 1# separated oxygen; Drying agent cooling: the 1# purified oxygen (S6) is divided into a 2# purified oxygen (S7), and the 2# purified oxygen (S7) is cooled to obtain pre-cooled purified oxygen (S8), and the pre-cooled purified oxygen (S8) is sent into the at least one dryer (101) to lower the bed temperature of the drying agent to obtain cooled oxygen, and the cooled oxygen is sequentially cooled and cooled by heat exchange to obtain 2# separated oxygen; The 1# purified oxygen (S6) is heated and warmed by heat exchange with the regenerated oxygen; The separated oxygen (S14) is the 1# separated oxygen or the 2# separated oxygen; When the number of the at least one dryer (101) is more than one, the connection mode of each dryer (101) is in parallel; In the step of drying and removing water, the water adsorption state of the drying agent in the at least one dryer (101) is detected, and when the water adsorption of the drying agent reaches a saturation state, the step of drying agent regeneration is performed; In the step of drying agent regeneration, the temperature of the warmed purified oxygen (S10) is detected, and when the temperature of the warmed purified oxygen (S10) is 100-200℃, the warmed purified oxygen (S10) is sent into the at least one dryer (101) to desorb the water adsorbed by the drying agent; when the temperature of the warmed purified oxygen (S10) is greater than 200℃, quenching oxygen (S16) is injected into the warmed purified oxygen (S10) to lower the temperature of the warmed purified oxygen (S10) to 100-200℃, and the quenching oxygen (S16) is another branch of the purified oxygen (S2); When one step is performed, the valves related to the other two steps are closed.

2. The method of claim 1, wherein, The flow directions of the oxygen to be dried (S1) and the separated oxygen (S14) in the at least one dryer (101) are the same, the flow directions of the warmed purified oxygen (S10) and the pre-cooled purified oxygen (S8) in the at least one dryer (101) are the same, and the flow directions of the oxygen to be dried (S1) and the warmed purified oxygen (S10) in the at least one dryer (101) are opposite; The purified oxygen (S2) and the regenerated purified oxygen (S5) are jointly extracted as purified oxygen. In the desiccant regeneration step, the regeneration oxygen is sequentially cooled by heat exchange, cooled by cooling, and separated to obtain a 1# condensate; In the desiccant cooling step, the cooling oxygen is sequentially cooled by cooling and separated to obtain a 2# condensate.

3. The method of claim 2, wherein, The oxygen to be dried (S1) and the oxygen after separation (S14) both enter from the bottom of at least one desiccator (101); The purified oxygen after heating (S10) and the purified oxygen after pre-cooling (S8) both enter from the top of at least one desiccator (101).

4. The method of claim 2, wherein, The at least one desiccator (101) is at least two in parallel; In the drying and water removal step, the desiccant in each desiccator adsorbs the moisture in the oxygen to be dried (S1) or the oxygen after separation (S14) sent into the desiccator to obtain purified oxygen or regenerated purified oxygen, the purified oxygen and all the remaining purified oxygen obtained by the remaining desiccators are combined to obtain purified oxygen (S2), and the regenerated purified oxygen and all the remaining regenerated purified oxygen obtained by the remaining desiccators are combined to obtain regenerated purified oxygen (S5); In the desiccant regeneration step, the desiccant in each desiccator is desorbed by the heated purified oxygen sent into the desiccator to obtain regeneration oxygen, and the regeneration oxygen and all the remaining regeneration oxygen obtained by the remaining desiccators are combined to obtain regeneration oxygen; In the desiccant cooling step, the desiccant in each desiccator is cooled by the pre-cooled purified oxygen sent into the desiccator to obtain cooling oxygen, and the cooling oxygen and all the remaining cooling oxygen obtained by the remaining desiccators are combined to obtain cooling oxygen.

5. The method of claim 4, wherein, The temperature of each desiccator during drying is 10-90℃, the pressure is 0.1-5.0MPa; the temperature during regeneration is 150-300℃, the pressure is 0.1-5.0MPa; the temperature during cooling is 7-50℃, and the pressure is 0.1-5.0MPa; The water content in the oxygen to be dried (S1) is not more than 2.5v%; the water content in the purified oxygen (S2) is not more than 1ppmv; The ratio of the amount of the 1# purified oxygen (S6) to the amount of the purified oxygen (S2) is in the range of 10%-35%; The ratio of the amount of the 2# purified oxygen (S7) to the amount of the purified oxygen (S2) is in the range of 10%-35%; The at least one desiccator (101) is selected from at least one of a fixed bed, a radial bed, and an axial-radial bed; The desiccant is selected from at least one of activated alumina, silica gel, molecular sieve, anhydrous magnesium sulfate, activated carbon, anhydrous calcium chloride, soda lime, solid caustic soda, anhydrous copper sulfate, diaphosphorus pentoxide, and calcium sulfate.

6. The method of claim 4, wherein, The temperature of each desiccator during drying is 20-60℃, the pressure is 0.5-3.2MPa; the temperature during regeneration is 210-260℃, the pressure is 0.5-3.2MPa; the temperature during cooling is 7-35℃, and the pressure is 0.5-3.2MPa; The ratio of the amount of the 1# purified oxygen (S6) to the amount of the purified oxygen (S2) is in the range of 15-25%; The ratio of the amount of the 2# purified oxygen (S7) to the amount of the purified oxygen (S2) is in the range of 15-25%; The ratio of the amount of the 2# purified oxygen (S7) to the amount of the purified oxygen (S2) is in the range of 15-25%; The desiccant is at least one selected from activated aluminum oxide, silica gel, molecular sieve, anhydrous magnesium sulfate, activated carbon, and anhydrous calcium chloride.

7. The method of claim 4, wherein, The desiccant is at least one selected from activated aluminum oxide, silica gel, molecular sieve, and activated carbon.

8. An apparatus for drying oxygen gas, characterized by The device comprises at least one desiccator (101), an oxygen drying heat exchanger (102), an oxygen electric heater (103), a purge cooler (104), a regeneration gas cooler (105), and an oxygen distribution tank (106); One end of the at least one desiccator (101) is connected to a pipeline for oxygen to be dried, a pipeline for oxygen after distribution, and a pipeline for cooled regeneration oxygen through independent valves, respectively, and the other end is connected to a pipeline for purified oxygen, a pipeline for purified regeneration oxygen, and a pipeline for pre-cooling / warming purified oxygen through independent valves, respectively; The pipeline for purified oxygen is branched into a pipeline for 1# purified oxygen, which is connected to the cold medium inlet of the oxygen drying heat exchanger (102), and the cold medium outlet of the oxygen drying heat exchanger (102) is connected to the inlet of the oxygen electric heater (103); The pipeline for 1# purified oxygen is branched into a pipeline for 2# purified oxygen, which is connected to the hot medium inlet of the purge cooler (104), and the outlet of the oxygen electric heater (103) and the hot medium outlet of the purge cooler (104) are jointly connected to the pipeline for pre-cooling / warming purified oxygen; The bottom of the at least one desiccator (101) is the pipeline for cooled regeneration oxygen, which is connected to the hot medium inlet of the oxygen drying heat exchanger (102), the hot medium outlet of the regeneration gas cooler (105) is connected to the inlet of the oxygen distribution tank (106), the gas phase outlet at the top of the oxygen distribution tank (106) is connected to the pipeline for oxygen after distribution, and a pipeline for condensed liquid is arranged at the bottom of the oxygen distribution tank (106); The at least one desiccator (101) is at least two in parallel; One end of each desiccator is connected to a pipeline for oxygen to be dried, a pipeline for oxygen after distribution, and a pipeline for cooled regeneration oxygen through independent valves, respectively, and the other end is connected to a pipeline for purified oxygen, a pipeline for purified regeneration oxygen, and a pipeline for pre-cooling / warming purified oxygen through independent valves, respectively; A 7# on-off valve (XV7) is arranged on the regenerative cooling oxygen outlet pipeline, and a regenerative oxygen on-off valve (XV8) is arranged on the refrigerant inlet pipeline of the oxygen drying heat exchanger (102) ） An optional other branch pipeline is branched from the purified oxygen outlet pipeline, and a quenching oxygen on-off valve (XV9) is arranged on the optional other branch pipeline; A temperature detector is arranged on the pipeline for pre-cooling / warming purified oxygen and the outlet pipeline of the oxygen electric heater (103); The at least one desiccator (101) is filled with a desiccant.

9. The apparatus of claim 8, wherein, The device further comprises a controller, which is used to control the opening and closing states of the independent valves at both ends of each desiccator, a 7# valve (XV7), a regeneration oxygen valve (XV8), and a quenching oxygen valve (XV9) according to the moisture adsorption state of the desiccant in each desiccator and / or the temperature detected by the temperature detector on the pipeline for pre-cooling / warming purified oxygen and the outlet pipeline of the oxygen electric heater (103) to realize the drying and water removal of oxygen to be dried, the regeneration of the desiccant, and the cooling of the desiccant. The controller is any one selected from PLC and DCS.

10. The apparatus of claim 8, wherein, The controller is PLC.

11. The apparatus of claim 9, wherein, The controller is used to control each dryer to dry the oxygen to be dried, regenerate the desiccant, or cool the desiccant according to the moisture adsorption state of the desiccant in each dryer, and / or the temperature detected by the temperature detector on the oxygen heating / cooling feed pipeline and the outlet pipeline of the oxygen electric heater (103).

12. The apparatus of claim 11, wherein, The at least one dryer (101) is selected from at least one of a fixed bed, a radial bed, and an axial-radial bed. The material of the at least one dryer (101), the oxygen electric heater (103), the oxygen feed and discharge pipelines, and each switch valve is independently selected from at least one of 304 / 304L, 316 / 316L, 321, and 347 stainless steel, Monel alloy, and nickel-based alloy. The desiccant is selected from at least one of activated alumina, silica gel, molecular sieve, anhydrous magnesium sulfate, activated carbon, anhydrous calcium chloride, soda lime, solid caustic soda, anhydrous copper sulfate, diaphosphorus pentoxide, and calcium sulfate.

13. The apparatus of claim 11, wherein, The desiccant is selected from at least one of activated alumina, silica gel, molecular sieve, anhydrous magnesium sulfate, activated carbon, and anhydrous calcium chloride. The refrigerant used by the purge cooler (104) and the regeneration gas cooler (105) is 7℃ chilled water.

14. The apparatus of claim 11, wherein, The desiccant is selected from at least one of activated alumina, silica gel, molecular sieve, and activated carbon.

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