Oxygen drying method and device

Abstract

The invention provides an oxygen drying method and device, and the method comprises the steps: carrying out the drying and water removal, drying agent regeneration and drying agent cooling of to-be-dried oxygen circulation through at least one dryer, carrying out the drying and water removal to obtain purified oxygen or regenerated purified oxygen, and in the drying agent regeneration, carrying out the heat exchange and temperature rise of one strand of purified oxygen and regenerated oxygen; regenerated oxygen in desiccant regeneration and cooled oxygen in desiccant cooling are cooled and subjected to liquid separation for recycling. According to the oxygen drying method provided by the invention, a multi-dryer sequential control process is adopted, a single dryer is sequentially subjected to adsorption drying water removal, drying agent regeneration and drying agent cooling, and the water content of an oxygen product is not greater than 1ppmv. Meanwhile, the method is simple in process, oxygen emptying is avoided, oxygen resources are utilized to the maximum extent, and the energy consumption is reduced. In addition, the situation that high temperature and impact working conditions occur simultaneously when the valve is opened suddenly in the high-purity oxygen environment is avoided, and the safety of the oxygen drying device is improved essentially.

Description

Technical Field

[0001] The invention relates to the technical field of oxygen drying, and in particular to a method and a device for oxygen drying. Background Art

[0002] Oxygen is widely used in petrochemical, coal chemical, precision electronics and biomedicine and other fields. The purity of oxygen directly determines the number of downstream application scenarios. Conventional oxygen preparation processes include: PSA method, membrane separation, cryogenic distillation and high-temperature alkaline molten salt catalysis. Among them, the cryogenic distillation process is suitable for large-scale production, with mature technology and high product purity, and can obtain liquid oxygen and gaseous oxygen at the same time. However, due to the high investment in the equipment, it is not suitable for occasions with low oxygen demand. The other three oxygen preparation processes are still far behind the cryogenic distillation process in terms of energy consumption, purity and technical maturity.

[0003] Industrial oxygen can come from air separation, and can also be produced by water electrolysis. Generally speaking, water electrolysis can produce two products, hydrogen and oxygen, at the same time, with hydrogen as the main product and oxygen as a by-product or directly discharged into the atmosphere. The oxygen prepared by water electrolysis has high purity (oxygen purity above 98.5%v) and contains trace amounts of water, hydrogen and nitrogen. The oxygen prepared by this technology is moderate in scale, which makes up for the defect that the low-temperature distillation method is not applicable to small and medium scale. In recent years, with the large-scale promotion of renewable energy hydrogen production projects, the by-product oxygen urgently needs to be processed for downstream applications. If the oxygen is purified according to conventional water electrolysis, the impurity content, material selection, and program control are difficult to meet the indicators and long-term operation requirements, which has become a technical bottleneck for the preparation of green oxygen by water electrolysis.

[0004] In the prior art, most of the oxygen produced by water electrolysis for hydrogen production is directly discharged into the atmosphere, and the drying and purification of oxygen is rarely involved. At present, oxygen drying usually adopts adsorption process and purified gas regeneration scheme. When deep dehydration is required, the operating temperature of the regeneration condition must be higher than 200°C, and the pure oxygen valve needs to be switched; at this time, oxygen impact occasions and high temperature conditions exceeding 200°C appear at the same time, superimposing the possibility of oxygen combustion and explosion, posing a potential safety risk. Based on the engineering experience and professional practice obtained by the inventors of the present invention in the long-term scientific research and development and engineering design in the field of water electrolysis for hydrogen production technology, the market is oriented, and the industry, academia and research are combined to solve the shortcomings of the existing oxygen utilization technology for water electrolysis for hydrogen production. After repeated research, experiments, engineering design and construction, an oxygen drying method with practical value was unexpectedly discovered.

[0005] Based on this background, the present invention studies a method and device for oxygen drying. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides an oxygen drying method and device to solve the problems of high energy consumption and safety risks in the prior art oxygen drying technology.

[0007] In order to achieve the above object, the first aspect of the present invention provides a method for drying oxygen, wherein the method comprises the following steps:

[0008] Drying and dehydration: sending the oxygen to be dried or the oxygen after liquid separation into at least one dryer, and using the desiccant in the at least one dryer to absorb the moisture in the oxygen to be dried or the oxygen after liquid separation to obtain purified oxygen or regenerate purified oxygen;

[0009] Desiccant regeneration: a stream of the purified oxygen is separated as 1# purified oxygen, the 1# purified oxygen is successively subjected to heat exchange and heating to obtain heated purified oxygen, the heated purified oxygen is sent to at least one dryer to desorb moisture adsorbed by the desiccant to obtain regenerated oxygen, the regenerated oxygen is successively subjected to heat exchange, cooling, and liquid separation to obtain 1# separated oxygen;

[0010] Desiccant cooling: a stream of 1# purified oxygen is separated as 2# purified oxygen, the 2# purified oxygen is cooled to obtain pre-cooled purified oxygen, the pre-cooled purified oxygen is sent to at least one dryer to reduce the bed temperature of the desiccant to obtain cooled oxygen, the cooled oxygen is sequentially cooled and separated to obtain 2# separated oxygen;

[0011] The 1# purified oxygen exchanges heat with the regenerated oxygen to increase temperature;

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

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

[0014] One end of the same side of the at least one dryer is respectively connected to the oxygen feed line to be dried, the oxygen feed line after liquid separation, and the regeneration cooling oxygen discharge line through independent switch valves, and the other end is respectively connected to the purified oxygen discharge line, the regeneration purified oxygen discharge line, and the heating / precooling purified oxygen feed line through independent switch valves;

[0015] A branch of the purified oxygen discharge pipeline is separated as a 1# purified oxygen pipeline connected to the refrigerant inlet of the oxygen drying heat exchanger, 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 1# purified oxygen pipeline is separated as the 2# purified oxygen pipeline to be connected to the heat medium inlet of the purge cooler, and the oxygen electric heater outlet and the purge cooler heat medium outlet are jointly connected to the heating / precooling purified oxygen feed pipeline;

[0017] The regenerated purified oxygen discharge pipeline is connected to the heat medium inlet of the oxygen drying heat exchanger, and another optional branch pipeline of the regenerated purified oxygen discharge pipeline is connected to the heat medium inlet of the regenerated gas cooler together with the heat medium outlet pipeline of the oxygen drying heat exchanger, and the heat medium outlet of the regenerated gas cooler is connected to the feed port of the oxygen liquid separator tank, and the gas phase outlet on the top of the oxygen liquid separator tank is connected to the oxygen feed pipeline after liquid separation, and a condensate discharge pipeline is provided at the bottom of the tank.

[0018] The effects of the present invention are:

[0019] (1) The oxygen drying method proposed in the present invention adopts a multi-dryer sequential control process, and a single dryer sequentially undergoes adsorption drying and water removal, 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 the present invention is simple, there is no oxygen venting, and oxygen resources are maximized.

[0020] (2) The oxygen drying method and device proposed in the present invention detects the oxygen temperature at the outlet of the oxygen heater and adopts 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, thereby avoiding the high temperature and impact conditions that occur when the valve is suddenly opened in a high-purity oxygen environment, thereby essentially improving the safety of the oxygen drying device.

[0021] (3) The oxygen drying method and device proposed in the present invention are provided with independent temperature detectors on the heating / precooling purified oxygen feed pipeline and the oxygen electric heater outlet pipeline. When it is detected that 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 opened, the heated purified oxygen entering the dryer is injected with quenched oxygen so that the temperature is lower than 200°C, thereby further reducing the high temperature and impact risks caused by the opening of the valve in a pure oxygen environment.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0024] Figure 1It is a process flow diagram of a specific implementation of the oxygen drying method and device proposed by the present invention.

[0025] Figure 2 It is a process flow diagram of another specific implementation of the oxygen drying method and device proposed by the present invention.

[0026] Figure 3 It is a process flow diagram of a third specific implementation mode of the oxygen drying method and device proposed by the present invention.

[0027] Figure 4 It is a process flow diagram of a fourth specific implementation mode of the oxygen drying method and device proposed by the present invention.

[0028] Description of reference numerals:

[0029] 101 - dryer, 102 - oxygen drying heat exchanger, 103 - oxygen electric heater, 104 - purge cooler, 105 - regeneration gas cooler, 106 - oxygen liquid separator;

[0030] S1—oxygen to be dried, S2—purified oxygen, S3—chilled water supply, S4—chilled water return, S5—regeneration purified oxygen, S6—1# purified oxygen, S7—2# purified oxygen, S8—precooling purified oxygen, S9—preheating purified oxygen, S10—heating purified oxygen, S11—precooling purified oxygen / heating purified oxygen, S12—oxygen after cooling, S13—cooling oxygen, S14—oxygen after separation, S15—dryer outlet oxygen, S16—quenching 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—regeneration oxygen switch valve, XV9—quenching oxygen switch valve. DETAILED DESCRIPTION

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

[0033] In the present disclosure, unless otherwise stated, directional words such as "upper" and "lower" generally refer to the upper and lower parts of a device in normal use. Figure 1In the drawing direction, "inside" and "outside" refer to the outline of the device. In addition, the terms "first, second, third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first, second, third" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0034] The present invention provides a method for oxygen drying, such as Figure 1 As shown, the method comprises the following steps:

[0035] Drying and dehydration: sending the oxygen to be dried S1 or the oxygen after liquid separation S14 into at least one dryer 101, and using the desiccant in at least one dryer 101 to adsorb the moisture in the oxygen to be dried S1 or the oxygen after liquid separation S14 to obtain purified oxygen S2 or regenerated purified oxygen S5;

[0036] Desiccant regeneration: a stream of purified oxygen S2 is separated as 1# purified oxygen S6, 1# purified oxygen S6 is successively subjected to heat exchange and heating to obtain heated purified oxygen S10, and the heated purified oxygen S10 is sent to at least one dryer 101 to desorb moisture adsorbed by the desiccant to obtain regenerated oxygen, and the regenerated oxygen is successively subjected to heat exchange, cooling, and liquid separation to obtain 1# separated oxygen;

[0037] Desiccant cooling: a stream of 1# purified oxygen S6 is separated as 2# purified oxygen S7, 2# purified oxygen S7 is cooled to obtain pre-cooled purified oxygen S8, the pre-cooled purified oxygen S8 is sent to at least one dryer 101 to reduce the bed temperature of the desiccant to obtain cooled oxygen, the cooled oxygen is sequentially cooled and separated to obtain 2# separated oxygen;

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

[0039] The oxygen after liquid separation S14 is 1# oxygen after liquid separation or 2# oxygen after liquid separation.

[0040] In the present invention, a multi-dryer sequential control process is adopted, and a single dryer sequentially undergoes adsorption drying and water removal, desiccant regeneration, and desiccant cooling, and the water content of the oxygen product is no more than 1ppmv. In addition, the oxygen drying process disclosed in the present invention is simple, there is no oxygen venting, and oxygen resources are maximized.

[0041] Preferably, when the number of the at least one dryer 101 is more than one, the connection mode of each dryer (101) is parallel connection;

[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 a saturated state;

[0043] The desiccant regeneration step also includes:

[0044] Detect the temperature of the heated purified oxygen S10. When the temperature of the heated purified oxygen S10 is 100° C.-200° C., send the heated purified oxygen S10 to at least one dryer 101 to desorb moisture adsorbed by the desiccant. When the temperature of the heated purified oxygen S10 is greater than 200° C., inject quenched oxygen S16 into the heated purified oxygen S10 to reduce the temperature of the heated purified oxygen S10 to 100° C.-200° C. The quenched oxygen S16 is another stream separated from the purified oxygen S2.

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

[0046] In the present invention, by detecting the temperature of the heated purified oxygen S10, a program-controlled method is adopted to open the valve on the regeneration gas pipeline at the top of the regeneration dryer when the temperature rises to 100°C, thereby avoiding the high temperature and impact conditions that occur when the valve is suddenly opened in a high-purity oxygen environment, thereby substantially improving the safety of the oxygen drying device.

[0047] In the present invention, when it is detected that 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 opened, the heated purified oxygen entering the dryer is injected to be lower than 200°C, thereby further reducing the high temperature and impact risks caused by the opening of the pure oxygen environment valve.

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

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

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

[0051] The purified oxygen S2 and the regenerated purified oxygen S5 are jointly produced as purified oxygen;

[0052] In the desiccant regeneration step, the regenerated oxygen is sequentially subjected to heat exchange, cooling, and liquid separation to obtain 1# condensate;

[0053] In the desiccant cooling step, the cooling oxygen is cooled and separated in sequence to obtain 2# condensate.

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

[0055] In the drying and dehydration step, the desiccant in each dryer is used to absorb the moisture in a stream of oxygen to be dried S1 or a stream of oxygen after separation S14 fed therein to obtain a stream of purified oxygen or a stream of regenerated purified oxygen. The stream of purified oxygen and all the remaining streams of purified oxygen obtained from the remaining dryers are merged into purified oxygen S2, and the stream of regenerated purified oxygen and all the remaining streams of regenerated purified oxygen obtained from the remaining dryers are merged into regenerated purified oxygen S5.

[0056] In the desiccant regeneration step, a stream of heated purified oxygen sent to each dryer desorbs moisture adsorbed by the desiccant to obtain a stream of regenerated oxygen, and the stream of regenerated oxygen is combined with all the remaining streams of regenerated oxygen obtained from the remaining dryers to form the regenerated oxygen;

[0057] In the desiccant cooling step, a stream of precooled purified oxygen is sent to each dryer to reduce the bed temperature of the desiccant to obtain a stream of cooling oxygen, and the stream of cooling oxygen is merged with all the remaining streams of cooling oxygen obtained from the remaining dryers to form cooling oxygen.

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

[0059] The water content of the oxygen to be dried S1 is not more than 2.5vt%; the water content of the purified oxygen S2 is not more than 1ppmv;

[0060] The ratio of the amount of 1# 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 2# 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 sieves, anhydrous magnesium sulfate, activated carbon, anhydrous calcium chloride, soda lime, solid caustic soda, anhydrous copper sulfate, phosphorus pentoxide, and calcium sulfate, preferably selected from at least one of activated alumina, silica gel, molecular sieves, anhydrous magnesium sulfate, activated carbon, and anhydrous calcium chloride, and further preferably selected from at least one of activated alumina, silica gel, molecular sieves, and activated carbon.

[0064] The present invention also provides a device for carrying out the above 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 liquid separator 106;

[0065] One end of the same side of at least one dryer 101 is connected to the oxygen feed line to be dried, the oxygen feed line after liquid separation, and the regeneration cooling oxygen discharge line through independent switch valves, and the other end is connected to the purified oxygen discharge line, the regeneration purified oxygen discharge line, and the heating / precooling purified oxygen feed line through independent switch valves;

[0066] A branch of the purified oxygen discharge pipeline is separated as the 1# purified oxygen pipeline to be connected to the refrigerant inlet of the oxygen drying heat exchanger 102, and 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 1# purified oxygen pipeline is separated as the 2# purified oxygen pipeline to be connected to the heat medium inlet of the purge cooler 104, and the outlet of the oxygen electric heater 103 and the heat medium outlet of the purge cooler 104 are connected to the heating / precooling purified oxygen feed pipeline together;

[0068] The regenerated purified oxygen discharge pipeline is connected to the heat medium inlet of the oxygen drying heat exchanger 102, and another optional branch pipeline is separated from the regenerated purified oxygen discharge pipeline and connected to the heat medium outlet pipeline of the oxygen drying heat exchanger 102 together with the heat medium inlet of the regenerated gas cooler 105, and the heat medium outlet of the regenerated gas cooler 105 is connected to the feed port of the oxygen liquid separator tank 106, and the gas phase outlet on the top of the oxygen liquid separator tank 106 is connected to the oxygen feed pipeline after liquid separation, and a condensate discharge pipeline is provided at the bottom of the tank.

[0069] Preferably, the dryers (101) are at least two 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 regeneration cooling oxygen discharge line through independent switch valves, and the other end is connected to the purified oxygen discharge line, the regeneration purified oxygen discharge line, and the heating / precooling purified oxygen feed line through independent switch valves;

[0071] A 7# switch valve XV7 is arranged on a branch line of the regenerated purified oxygen discharge pipeline, a regenerated oxygen switch valve XV8 is arranged on the refrigerant inlet pipeline of the oxygen drying heat exchanger 102, and a quenching oxygen switch valve XV9 is arranged on another branch line of the purified oxygen discharge pipeline;

[0072] The heating / precooling purified oxygen feed pipeline and the oxygen electric heater 103 outlet pipeline are provided with independent temperature detectors;

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

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

[0075] The controller is selected from any one of PLC and DCS, preferably PLC.

[0076] According to a preferred embodiment of the present invention, the controller is used to control each dryer to dry and dehydrate the oxygen to be dried and regenerate the desiccant, or to control each dryer to dry and dehydrate the oxygen to be dried and 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 heating / precooling purified oxygen feed pipeline and the outlet pipeline of the oxygen electric heater 103.

[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] The material of at least one dryer 101, oxygen electric heater 103, oxygen inlet and outlet pipelines and each switch valve is independently selected from at least one of 304 / 304L, 316 / 316L, 321, 347 stainless steel, monel alloy and nickel-based alloy;

[0079] The desiccant is selected from at least one of activated aluminum oxide, silica gel, molecular sieve, anhydrous magnesium sulfate, activated carbon, anhydrous calcium chloride, soda lime, solid caustic soda, anhydrous copper sulfate, phosphorus pentoxide, and calcium sulfate, preferably selected from at least one of activated aluminum oxide, silica gel, molecular sieve, anhydrous magnesium sulfate, activated carbon, and anhydrous calcium chloride, and further preferably selected from at least one of activated aluminum oxide, 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 by way of examples.

[0082] Example 1

[0083] like Figure 1 As shown, this embodiment provides an oxygen drying device, 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 liquid separator 106;

[0084] One end of the same side of the three parallel dryers 101 is respectively connected to the oxygen feed pipeline to be dried, the oxygen feed pipeline after liquid separation, and the regeneration cooling oxygen discharge pipeline, and the other end is respectively connected to the purified oxygen discharge pipeline, the regeneration purified oxygen discharge pipeline, and the heating / precooling purified oxygen feed pipeline;

[0085] A branch of the purified oxygen discharge pipeline is separated as the 1# purified oxygen pipeline to be connected to the refrigerant inlet of the oxygen drying heat exchanger 102, and 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 1# purified oxygen pipeline is separated as the 2# purified oxygen pipeline to be connected to the heat medium inlet of the purge cooler 104, and the outlet of the oxygen electric heater 103 and the heat medium outlet of the purge cooler 104 are connected to the heating / precooling purified oxygen feed pipeline together;

[0087] The regenerated purified oxygen discharge pipeline is connected to the heat medium inlet of the oxygen drying heat exchanger 102, and another optional branch pipeline of the regenerated purified oxygen discharge pipeline is connected to the heat medium inlet of the regenerated gas cooler 105 together with the heat medium outlet pipeline of the oxygen drying heat exchanger 102, and the heat medium outlet of the regenerated gas cooler 105 is connected to the feed port of the oxygen liquid separator 106, and the gas phase outlet on the top of the oxygen liquid separator 106 is connected to the oxygen feed pipeline after liquid separation, and a condensate discharge pipeline is provided at the bottom of the tank;

[0088] One end of each dryer is connected to the oxygen feed line to be dried, the oxygen feed line after liquid separation, and the regeneration cooling oxygen discharge line through independent switch valves, and the other end is connected to the purified oxygen discharge line, the regeneration purified oxygen discharge line, and the heating / precooling purified oxygen feed line through independent switch valves;

[0089] A 7# switch valve XV7 is provided on a branch line of the regenerated purified oxygen discharge line, and a regenerated oxygen switch valve XV8 is provided on the refrigerant inlet line of the oxygen drying heat exchanger 102;

[0090] The heating / precooling purified oxygen feed pipeline and the oxygen electric heater 103 outlet pipeline are provided with independent temperature detectors;

[0091] Each dryer is filled with a desiccant;

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

[0093] The controller is PLC;

[0094] The controller is used to control each dryer to dry and dehydrate the oxygen to be dried and regenerate the desiccant, or to control each dryer to dry and dehydrate the oxygen to be dried and cool the desiccant according to the moisture adsorption state of the desiccant in each dryer of the three parallel dryers 101 and the temperature detected by the temperature detector (not shown) on the heating / precooling purified oxygen feed pipeline and the outlet pipeline of the oxygen electric heater 103;

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

[0096] The three parallel dryers 101, the oxygen electric heater 103, the oxygen inlet and outlet pipelines and each switch valve are all 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] The dryers 101A, 101B, and 101C sequentially undergo drying and water removal, desiccant regeneration, and desiccant cooling stages to achieve continuous operation of the drying device;

[0100] Drying and dehydration: The oxygen to be dried S1 is fed into the bottom inlet of the dryer 101A, and the water in the oxygen to be dried S1 is physically adsorbed by the desiccant to obtain purified oxygen S2. At this time, valves XV1A and XV4A are in an open state, and valves XV2A, XV3A, XV5A, and XV6A are in a closed state; the dryer 101A is in a working state until the water adsorption is saturated; the dryers 101B and 101C are in a regeneration and standby state;

[0101] Desiccant regeneration: After the desiccant in the dryer 101B is saturated with moisture, it enters the regeneration stage. The inlet and outlet gas valves XV1B and XV4B of the dryer 101B are closed; 1# purified oxygen S6 is drawn out from the purified oxygen S2, and is heated by the oxygen drying heat exchanger 102 to obtain preheated purified oxygen S9. The preheated purified oxygen S9 is heated by the oxygen electric heater 103 to obtain heated purified oxygen S10, which enters the dryer 101B from the top regeneration inlet. The XV6B and XV3B valves are opened. When the temperature of the heated purified oxygen S10 reaches 150°C, the XV6B valve is opened through program control. Under the action of the heated purified oxygen S10, the desiccant adsorbs The attached water is desorbed into gaseous oxygen and leaves the bottom of the dryer 101B as the dryer outlet oxygen S15, and then passes through the oxygen drying heat exchanger 102 and the regeneration gas cooler 105 to obtain the cooled oxygen S12 and the cooled oxygen S13, and the cooled oxygen S13 is sent to the oxygen separator 106, and 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, and the valves XV2C and XV5C are opened, and the regenerated purified oxygen S5 is combined with the purified oxygen S2 to send out of the device until the regeneration is completed, and the oxygen electric heater 103 and the inlet and outlet valves on the regeneration gas path are closed;

[0102] Desiccant cooling: 2# purified oxygen S7 is drawn from 1# purified oxygen S6, XV8 valve is closed, and pre-cooled purified oxygen S8 is obtained through purge cooler 104, and enters dryer 101B from the top cooling inlet. Under the action of pre-cooled purified oxygen S8, the desiccant bed temperature is reduced, and then it leaves from the bottom of dryer 101B, and passes through oxygen drying heat exchanger 102 cross-line, XV7 valve is opened, and regeneration gas cooler 105 in sequence to obtain cooled oxygen S12 and cooled oxygen S13, and the cooled oxygen S13 is sent to oxygen separator 106, and the separated condensate is discharged from the bottom of oxygen separator 106. The oxygen at the top of oxygen separator 106 enters the next stage of regeneration completed dryer 101C, and the purified oxygen S5 is combined with the purified oxygen S2 to send out the device until the cooling is completed, and 2# purified oxygen S7 and the inlet and outlet valves of the cooling gas line are closed. At this time, dryer 101B has completed complete regeneration and serves as a standby dryer;

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

[0104] In this embodiment, the opening and closing states of each switch valve at this stage are shown in Table 1;

[0105] Each dryer enters the next stage according to the program-controlled sequence. At this time, the adsorption dryer 101A enters the regeneration state, the regeneration dryer 101B enters the standby state, and the standby dryer 101C enters the adsorption drying state. The three dryers 101 still follow the above three steps of adsorption drying, adsorbent regeneration, and adsorbent cooling to achieve continuous regeneration of oxygen drying.

[0106] In this embodiment, the temperature of the dryer 101A during normal drying is 35° C. and the pressure is 1.5 MPa; the temperature of the dryer 101B during regeneration is 250° C. and the pressure is 1.5 MPa; the temperature of the 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 not more than 1.0% (volume fraction; the water content in the purified oxygen is 0.5 ppmv. The ratio of the amount of 1# purified oxygen S6 to the amount of purified oxygen S2 is 20%, and the ratio of the amount of 2# purified oxygen S7 to the amount of purified oxygen S2 is 15%.

[0107] This embodiment provides three dryers and simultaneously detects the temperature of the regenerated oxygen to open the valve on the regenerated gas pipeline, thereby achieving no external discharge of oxygen and avoiding high-temperature shock conditions, thereby improving the intrinsic safety of the device.

[0108] Table 1 Opening and closing status of switch valve

[0109] Switching valve Drying and dehydration Desiccant regeneration Desiccant cooling 101A XV1A open - - XV2A close - - XV3A close - - XV4A open - - XV5A close - - XV6A close - - 101B XV1B - close close XV2B - close close XV3B - open open XV4B - close close XV5B - close close XV6B - open open 101C XV1C - close close XV2C - open open XV3C - close close XV4C - close close XV5C - open open XV6C - close close XV7 close open XV8 open close

[0110] Example 2

[0111] like Figure 2 As shown, this embodiment provides another oxygen drying device and method. The difference between this embodiment and embodiment 1 is that only two dryers are provided, and the other parameters are the same. This embodiment is suitable for working conditions where the water content in the oxygen to be dried is small, such as the volume fraction of the water content is 0.2%, and the water content of the purified oxygen is 0.5ppmv.

[0112] Example 3

[0113] like Figure 3 As shown, this embodiment provides a third oxygen drying device and method. Compared with Example 1, the only difference is that four dryers are provided, and the other parameters are the same. This embodiment is suitable for working conditions where there is a lot of moisture in the oxygen to be dried, such as when the volume fraction of the water content is 2.0%, and the water content of the purified oxygen is 0.8ppmv. In this embodiment, silica gel is used as the desiccant, and the dryer adopts an axial radial type. This embodiment uses four dryers to effectively deal with the drying of oxygen with a high moisture content, and realizes the continuous operation of the drying process.

[0114] Example 4

[0115] like Figure 4As shown, this embodiment provides a fourth oxygen drying device and method. In this embodiment, three dryers are also used. Compared with Example 1, the difference is that a quenching oxygen S16 injection point 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 is greater than 200°C, and at this time the air intake valve XV6 on the regeneration pipeline at the top of the dryer is closed, the air intake valve XV9 on the quenching oxygen S16 is opened so that the temperature of the heated purified oxygen S10 is not greater than 200°C before the air intake 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, thereby improving the inherent safety of the device.

[0116] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes 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 oxygen drying, characterized in that: The method comprises the following steps: Drying and dehydrating: sending the oxygen to be dried (S1) or the oxygen after liquid separation (S14) into at least one dryer (101), and using the desiccant in the at least one dryer (101) to adsorb the moisture in the oxygen to be dried (S1) or the oxygen after liquid separation (S14) to obtain purified oxygen (S2) or regenerate purified oxygen (S5); Desiccant regeneration: a stream of the purified oxygen (S2) is separated as 1# purified oxygen (S6), the 1# purified oxygen (S6) is successively subjected to heat exchange and heating to obtain heated purified oxygen (S10), the heated purified oxygen (S10) is sent to at least one dryer (101) to desorb moisture adsorbed by the desiccant to obtain regenerated oxygen, the regenerated oxygen is successively subjected to heat exchange and cooling, cooling and liquid separation to obtain 1# separated oxygen; Desiccant cooling: a stream of 1# purified oxygen (S6) is separated as 2# purified oxygen (S7), the 2# purified oxygen (S7) is cooled to obtain pre-cooled purified oxygen (S8), the pre-cooled purified oxygen (S8) is sent to at least one dryer (101) to reduce the bed temperature of the desiccant to obtain cooled oxygen, the cooled oxygen is sequentially cooled and separated to obtain 2# separated oxygen; The 1# purified oxygen (S6) exchanges heat with the regenerated oxygen to increase the temperature; The oxygen after liquid separation (S14) is the oxygen after liquid separation No. 1 or the oxygen after liquid separation No.

2.

2. The method according to claim 1, characterized in that When the number of the at least one dryer (101) is more than one, the connection mode of each dryer (101) is parallel connection; The drying and dehydration step further 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 a saturated state; The desiccant regeneration step further comprises: detecting the temperature of the heated purified oxygen (S10); when the temperature of the heated purified oxygen (S10) is 100° C.-200° C., sending the heated purified oxygen (S10) into at least one dryer (101) to desorb moisture adsorbed by a desiccant; when the temperature of the heated purified oxygen (S10) is greater than 200° C., injecting quenched oxygen (S16) into the heated purified oxygen (S10) to reduce the temperature of the heated purified oxygen (S10) to 100° C.-200° C., the quenched oxygen (S16) being another stream separated from the purified oxygen (S2); When one step is executed, the gas line valves related to the other two steps are closed.

3. The method according to claim 2, characterized in that The oxygen to be dried (S1) and the oxygen after separation (S14) flow in the same direction in the at least one dryer (101); preferably, both enter from the bottom of the at least one dryer (101); The heated purified oxygen (S10) and the pre-cooled purified oxygen (S8) have the same flow direction in the at least one dryer (101); preferably, both enter from the top of the at least one dryer (101); The flow directions of the oxygen to be dried (S1) and the heated 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 regenerated oxygen is sequentially subjected to heat exchange, cooling, and liquid separation to obtain 1# condensate; In the desiccant cooling step, the cooling oxygen is sequentially cooled and separated to obtain 2# condensate.

4. The method according to claim 3, characterized in that The at least one dryer (101) is at least two connected in parallel; In the drying and dehydration step, the desiccant in each dryer is used to absorb the moisture in a stream of oxygen to be dried (S1) or a stream of oxygen after separation (S14) fed therein to obtain a stream of purified oxygen or a stream of regenerated purified oxygen, the stream of purified oxygen and all the remaining streams of purified oxygen obtained by the remaining dryers are merged into purified oxygen (S2), and the stream of regenerated purified oxygen and all the remaining streams of regenerated purified oxygen obtained by the remaining dryers are merged into regenerated purified oxygen (S5); In the desiccant regeneration step, a stream of heated purified oxygen sent to each dryer desorbs moisture adsorbed by the desiccant to obtain a stream of regenerated oxygen, and the stream of regenerated oxygen and all the remaining streams of regenerated oxygen obtained from the remaining dryers merge into the regenerated oxygen; In the desiccant cooling step, a stream of precooled purified oxygen is sent to each dryer to lower the bed temperature of the desiccant to obtain a stream of cooling oxygen, and the stream of cooling oxygen is merged with all the remaining streams of cooling oxygen obtained from the remaining dryers to form cooling oxygen.

5. The method according to claim 4, characterized in that The temperature of each dryer during drying is 10-90°C, preferably 20-60°C, and the pressure is 0.1-5.0MPa, preferably 0.5-3.2MPa; the temperature during regeneration is 150-300°C, preferably 210-260°C, and the pressure is 0.1-5.0MPa, preferably 0.5-3.2MPa; the temperature during cooling is 7-50°C, preferably 7-35°C, and the pressure is 0.1-5.0MPa, preferably 0.5-3.2MPa; 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 first purified oxygen (S6) to the amount of the purified oxygen (S2) is in the range of 10%-35%, preferably 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 10%-35%, preferably 15-25%; 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 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, 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 further preferably selected from at least one of activated alumina, silica gel, molecular sieve, and activated carbon.

6. An oxygen drying device, characterized in that: The device comprises 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 liquid separator (106); One end of the at least one dryer (101) on the same side is connected to the oxygen feed line to be dried, the oxygen feed line after liquid separation, and the regeneration cooling oxygen discharge line through independent switch valves, and the other end is connected to the purified oxygen discharge line, the regeneration purified oxygen discharge line, and the heating / precooling purified oxygen feed line through independent switch valves; A branch of the purified oxygen discharge pipeline is separated as a 1# purified oxygen pipeline connected to the refrigerant inlet of the oxygen drying heat exchanger (102), and the refrigerant outlet of the oxygen drying heat exchanger (102) is connected to the inlet of the oxygen electric heater (103); A branch of the 1# purified oxygen pipeline is separated as the 2# purified oxygen pipeline connected to the heat medium inlet of the purge cooler (104), and the outlet of the oxygen electric heater (103) and the heat medium outlet of the purge cooler (104) are connected to the heating / precooling purified oxygen feed pipeline; The regenerated purified oxygen discharge pipeline is connected to the heat medium inlet of the oxygen drying heat exchanger (102), and another optional branch pipeline of the regenerated purified oxygen discharge pipeline is connected to the heat medium inlet of the regenerated gas cooler (105) together with the heat medium outlet pipeline of the oxygen drying heat exchanger (102), and the heat medium outlet of the regenerated gas cooler (105) is connected to the feed port of the oxygen liquid separation tank (106), and the gas phase outlet at the top of the oxygen liquid separation tank (106) is connected to the oxygen feed pipeline after liquid separation, and a condensate discharge pipeline is arranged at the bottom of the tank.

7. The device according to claim 6, characterized in that The at least one dryer (101) is at least two connected in parallel; One end of each dryer is connected to the oxygen feed line to be dried, the oxygen feed line after liquid separation, and the regeneration cooling oxygen discharge line through independent switch valves, and the other end is connected to the purified oxygen discharge line, the regeneration purified oxygen discharge line, and the heating / precooling purified oxygen feed line through independent switch valves; A 7# switch valve (XV7) is provided on a branch line branched from the regenerated purified oxygen discharge pipeline, a regenerated oxygen switch valve (XV8) is provided on the refrigerant inlet pipeline of the oxygen drying heat exchanger (102), and a quenching oxygen switch valve (XV9) is provided on another branch line optionally branched from the purified oxygen discharge pipeline; The heating / precooling purified oxygen feed pipeline and the oxygen electric heater (103) outlet pipeline are provided with respective independent temperature detectors; The at least one dryer (101) is filled with a desiccant.

8. The device according to claim 7, characterized in that The device further comprises a controller, which is used to control the opening and closing states of the independent switch valves at both ends of each dryer, the 7# switch valve (XV7), the regeneration oxygen switch valve (XV8) and the quenching oxygen switch valve (XV9) according to the moisture adsorption state of the desiccant in each dryer and / or the temperature detected by the temperature detectors on the heating / precooling purified oxygen feed pipeline and the outlet pipeline of the oxygen electric heater (103), so as to achieve drying and dehydration of the oxygen to be dried, desiccant regeneration and desiccant cooling in each dryer; The controller is selected from any one of PLC and DCS, preferably PLC.

9. The device according to claim 8, characterized in that The controller is used to control each dryer to dry and dehydrate the oxygen to be dried and regenerate the desiccant, or to control each dryer to dry and dehydrate the oxygen to be dried and 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 heating / precooling purified oxygen feed pipeline and the outlet pipeline of the oxygen electric heater (103).

10. The device according to claim 9, characterized in that 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 inlet and outlet pipelines and each switch valve is independently selected from at least one of 304 / 304L, 316 / 316L, 321, 347 stainless steel, monel alloy and nickel-based alloy; The desiccant is selected from at least one of activated aluminum oxide, silica gel, molecular sieve, anhydrous magnesium sulfate, activated carbon, anhydrous calcium chloride, soda lime, solid caustic soda, anhydrous copper sulfate, phosphorus pentoxide, and calcium sulfate, preferably selected from at least one of activated aluminum oxide, silica gel, molecular sieve, anhydrous magnesium sulfate, activated carbon, and anhydrous calcium chloride, and further preferably selected from at least one of activated aluminum oxide, silica gel, molecular sieve, and activated carbon; The refrigerant used in the purge cooler (104) and the regeneration gas cooler (105) is preferably 7°C chilled water.

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