Pressure swing adsorption hydrogen drying system and drying method

Abstract

The application discloses a pressure swing adsorption type hydrogen drying system, which comprises three drying towers, a raw gas input pipeline, a product gas output pipeline and a waste gas output pipeline. Opposite ends of each drying tower are respectively provided with a first pipeline and a second pipeline which are communicated with the inside of the drying tower. Each first pipeline is communicated with the raw gas input pipeline and the waste gas output pipeline. Each second pipeline is communicated with the product gas output pipeline. Any two second pipelines are communicated through a regeneration pipeline. One second pipeline is correspondingly connected with one pressure boosting pipeline. The pressure boosting pipelines are communicated with each other. A regeneration control assembly is arranged on each regeneration pipeline. A pressure boosting control assembly is arranged on each pressure boosting pipeline. The application fully utilizes the high-pressure dried hydrogen in the adsorbent gap of the tower which has just completed the adsorption process, regenerates the drying agent in the regeneration tower and saves the hydrogen consumption. The application further discloses a drying method.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen production, and particularly relates to a pressure swing adsorption type hydrogen drying system and a drying method. BACKGROUND

[0002] The drying device used in the existing PEM electrolysis hydrogen production system is a two-tower pressure swing adsorption. The process is as follows: the hydrogen produced by the PEM electrolysis cell first removes the liquid droplets in the hydrogen through a gas-liquid separator, then the hydrogen is cooled and further removes the moisture through a cold dryer, and then enters the pressure swing adsorption device composed of two adsorption towers, and the water vapor component is selectively adsorbed by the special water molecular sieve adsorbent filled in the tower, and the product gas H2 is discharged from the top of the tower with a purity of 99.9998%. The pressure swing adsorption includes an adsorption process and an adsorbent regeneration process. After the adsorption process is completed, the adsorbent regeneration process is carried out. When the pressure is reduced, the water vapor adsorbed by the adsorbent is desorbed and discharged through the bottom of the tower, and the adsorbent is regenerated after being washed. The regenerated adsorbent can be converted into adsorption after being uniformly pressurized and pressurized. The two towers are used alternately to achieve the purpose of continuously separating water vapor from hydrogen.

[0003] In the existing two-tower pressure swing adsorption, one of the towers needs to be immediately converted to the regeneration process after the adsorption process is completed. At this time, there is high-pressure dry hydrogen in the gap between the adsorbents in the tower, which cannot be utilized and can only be discharged through the bottom of the tower, causing waste of hydrogen. SUMMARY

[0004] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present application is to provide a pressure swing adsorption type hydrogen drying system and method, which aims to solve the problems in the background art. By using a three-tower structure of the pressure swing adsorption device, the high-pressure dry hydrogen in the gap between the adsorbents of the tower just after the adsorption process is fully utilized, the drying agent in the regeneration tower is regenerated, the amount of hydrogen is saved, and the waste of hydrogen is reduced.

[0005] The present application provides a pressure swing adsorption type hydrogen drying system, which comprises three drying towers, a raw gas input pipeline, a product gas output pipeline and a waste gas output pipeline. Each of the drying towers is provided with a first pipeline and a second pipeline at opposite ends thereof, the first pipelines are in communication with the raw gas input pipeline and the waste gas output pipeline, the second pipelines are in communication with the product gas output pipeline, any two of the second pipelines are connected by a regeneration pipeline, one of the second pipelines is connected with a pressure increasing pipeline, the pressure increasing pipelines are in communication with each other, the regeneration control components are arranged on the regeneration pipelines, and the pressure increasing control components are arranged on the pressure increasing pipelines.

[0006] Further, each of the regeneration control assemblies comprises two regeneration one-way electromagnetic valves, and the installation directions of the two regeneration one-way electromagnetic valves are opposite.

[0007] Further, each of the pressure boosting control assemblies comprises a pressure boosting one-way electromagnetic valve, and the inlets of the pressure boosting one-way electromagnetic valves are connected or the outlets of the pressure boosting one-way electromagnetic valves are connected.

[0008] Further, the regeneration control assemblies further comprise regeneration throttles, and the pressure boosting control assemblies further comprise pressure boosting throttles, the throttling diameters of the pressure boosting throttles are the same, and the throttling diameters of the pressure boosting throttles are greater than the throttling diameters of the regeneration throttles.

[0009] Further, the second pipeline is communicated with the product gas output pipeline through a check valve.

[0010] Further, the first pipeline is communicated with the raw gas input pipeline through an input electromagnetic valve, and the first pipeline is communicated with the waste gas output pipeline through an output electromagnetic valve.

[0011] Further, the outlet end of the product gas output pipeline is provided with a pre-valve pressure regulating valve.

[0012] The application further provides a drying method, and provides the pressure swing adsorption type hydrogen drying system, three drying towers are subjected to repeated cycle steps for pressure swing adsorption drying of hydrogen, and the repeated cycle steps of each drying tower are sequentially an adsorption step, a pressure reduction step, a regeneration step and a pressure boosting step.

[0013] Further, the adsorption step is that the raw gas is sequentially conveyed to the drying tower through the raw gas input pipeline and the first pipeline, and the water vapor in the product gas is less than 2ppm after being adsorbed by the adsorbent in the drying tower.

[0014] Further, the pressure reduction step comprises a forward pressure reduction step, a pressure maintaining step and a reverse pressure reduction step, the forward pressure reduction step is that high-pressure gas in the drying tower flows out along the gas flow direction during adsorption to provide flushing high-pressure gas for the regenerated drying tower, the pressure maintaining step is that the drying tower maintains constant pressure after the forward pressure reduction step, and the reverse pressure reduction step is that the remaining gas in the drying tower is discharged through the first pipeline and the waste gas output pipeline in the reverse direction of the gas flow direction during adsorption.

[0015] Further, the regeneration step comprises a first regeneration step and a second regeneration step, the first regeneration step is that the drying tower is subjected to first flushing by using high-pressure gas in the reverse direction of the gas flow direction during adsorption, and the second regeneration step is that the drying tower is subjected to second flushing by using product gas in the reverse direction of the gas flow direction during adsorption.

[0016] Further, the pressure boosting step includes two paths, one of which is that a part of the product gas enters the drying tower against the gas flow direction during adsorption through the pressure boosting pipeline, and the other of which is that a part of the product gas enters the drying tower against the gas flow direction during adsorption through the regeneration pipeline.

[0017] Further, the outlet end of the product gas output pipeline is provided with a pre-valve pressure regulating valve, and the set value of the pre-valve pressure regulating valve is 4 MPa.

[0018] The variable pressure adsorption type hydrogen drying system provided by the application adopts a structure of three drying towers, controls the opening and closing of each pipeline, uses the high-pressure dried hydrogen gas in the drying tower at the end of the adsorption process to perform primary regeneration on the drying tower about to start regeneration, and then uses the dried product hydrogen gas to perform subsequent regeneration, thereby saving the amount of product hydrogen gas and saving hydrogen gas. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 The figure is a structural schematic diagram of the variable pressure adsorption type hydrogen drying system of the embodiment of the present application.

[0021] In the figure, 1 is a raw material gas input pipeline, 2 is a product gas output pipeline, 3 is a waste gas output pipeline, 4 is a regeneration pipeline, 5 is a pressure boosting pipeline, 6 is a drying tower, 61 is a first pipeline, 62 is a second pipeline, 7 is a regeneration control assembly, 71A, 72A, 71B, 72B, 71C, 72C are regeneration one-way electromagnetic valves, 73A, 73B, 73C are regeneration throttles, 8 is a pressure boosting control assembly, 81A, 81B, 81C are pressure boosting one-way electromagnetic valves, 82A, 82B, 82C are pressure boosting throttles, 9A, 9B, 9C are check valves, 10A, 10B, 10C are input electromagnetic valves, 11A, 11B, 11C are output electromagnetic valves, and 12 is a pre-valve pressure regulating valve. DETAILED DESCRIPTION

[0022] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the description of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0023] The terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," and "outer" used in the specification and claims of this invention indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use. They are used only for the convenience of description and simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] The terms "first," "second," "third," etc., used in the specification and claims of this invention are merely for distinguishing elements with similar properties, and do not indicate or imply relative importance or a specific order.

[0025] The terms “comprising,” “including,” or any other variations thereof used in the specification and claims of this invention are intended to cover a non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0026] This invention provides a pressure swing adsorption (PSA) hydrogen drying system, such as... Figure 1 As shown, the system includes three drying towers 6, a first pipeline 61, a second pipeline 62, a raw material gas inlet pipeline 1, a product gas outlet pipeline 2, a waste gas outlet pipeline 3, a regeneration pipeline 4, and a pressurization pipeline 5. The three drying towers 6 are used to remove water vapor from the raw material gas (raw material hydrogen). The raw material gas inlet pipeline 1 is used to supply the raw material gas into the system. The product gas outlet pipeline 2 is used to output the dried product gas (dried hydrogen) from the system. The waste gas outlet pipeline 3 is used to discharge the waste gas (residual gas or flushing gas) from the drying towers 6 into the system. Each drying tower 6 has a first pipeline 61 and a second pipeline 62 connected to its interior at opposite ends. Each first pipeline 61 is connected to the raw material gas input pipeline 1 and the waste gas output pipeline 3. Each first pipeline 61 is connected to the raw material gas input pipeline 1, allowing the raw material gas to sequentially enter the corresponding drying tower 6 via the raw material gas input pipeline 1 and the first pipeline 61 for adsorption and drying. Each first pipeline 61 is connected to the waste gas output pipeline 3, allowing the waste gas to sequentially exit the corresponding drying tower 6 via the first pipeline 61 and the waste gas output pipeline 3. Each second pipeline 62 is connected to the product gas output pipeline 2, allowing the product gas to sequentially exit via the second pipeline 62 and the product gas output pipeline 2. Any two drying towers 6 are connected by a regeneration pipeline 4, and each second pipeline 62 is connected to a corresponding booster pipeline 5. All booster pipelines 5 are interconnected. Each regeneration pipeline 4 is equipped with a regeneration control component 7 for controlling the opening and closing of the corresponding regeneration pipeline 4; each booster pipeline 5 is equipped with a booster control component 8 for controlling the opening and closing of the corresponding booster pipeline 5.

[0027] The variable pressure adsorption type hydrogen drying system provided by the application adopts the structure of three drying towers 6, controls the switches of pipelines, uses the high-pressure dried hydrogen in the drying tower 6 ending the adsorption process to carry out the first regeneration (primary regeneration) of the drying tower 6 starting the regeneration, and then uses the dried product hydrogen to carry out the second regeneration (subsequent regeneration), thereby saving the use amount of product hydrogen, saving hydrogen, and improving economic benefits.

[0028] As an embodiment, as shown in Figure 1 The regeneration control assembly 7 includes two regeneration one-way electromagnetic valves 71A and 72A (or regeneration one-way electromagnetic valves 71B and 72B, or regeneration one-way electromagnetic valves 71C and 72C); the installation directions of the two regeneration one-way electromagnetic valves 71A and 72A (or regeneration one-way electromagnetic valves 71B and 72B, or regeneration one-way electromagnetic valves 71C and 72C) are opposite. For example, the inlets of the two regeneration one-way electromagnetic valves 71A and 72A can be connected, or the outlets of the two regeneration one-way electromagnetic valves 71A and 72A can be connected. When the two regeneration one-way electromagnetic valves (such as the regeneration one-way electromagnetic valves 71A and 72A) are opened at the same time and closed at the same time, the reverse conduction problem caused by the fact that the outlet pressure is higher than the inlet pressure when a single regeneration one-way electromagnetic valve (such as the regeneration one-way electromagnetic valve 71A) is in a closed state can be avoided.

[0029] Specifically, as shown in Figure 1As shown, the regeneration one-way solenoid valves 71A and 72A are installed in opposite directions. One solenoid valve is installed in the same direction as the gas flow in the pipeline, while the other is installed in the opposite direction. For example, when the high-pressure hydrogen in the adsorbent gap in drying tower B regenerates the adsorbent in drying tower A for the first time, the gas flow is from drying tower B to drying tower A. The installation direction of the regeneration one-way solenoid valve 72A is opposite to the direction of the gas flow from drying tower B to drying tower A (the direction of the regeneration flushing gas flow). The pressure of the high-pressure hydrogen in drying tower B is greater than the set opening pressure of the regeneration one-way solenoid valve 72A, so the high-pressure hydrogen is sufficient to open the regeneration one-way solenoid valve 72A and flow towards drying tower A. However, when the pressure on the drying tower A side increases and becomes greater than the pressure on the drying tower B side, ... There is a possibility of gas flowing in reverse from drying tower A to drying tower B, affecting the normal operation of the system. In this case, a regeneration one-way solenoid valve 71A is installed on regeneration pipeline 4, and the installation direction of regeneration one-way solenoid valve 71A is opposite to that of regeneration one-way solenoid valve 72A. That is, the installation direction of regeneration one-way solenoid valve 71A is opposite to the direction of gas flow from drying tower A to drying tower B. At this time, because the gas pressure on the drying tower A side does not reach the set opening pressure of regeneration one-way solenoid valve 71A, the reverse flow of gas from drying tower A to drying tower B is prevented. This embodiment effectively prevents the reverse flow problem caused by the outlet pressure (drying tower A side) being higher than the inlet pressure (drying tower B side) when regeneration one-way solenoid valves 71A and 72A are in the closed state, greatly improving the stability and reliability of the system operation. Of course, the installation direction of the regeneration one-way solenoid valve 72A can be the same as the regeneration flushing airflow direction (from drying tower B to drying tower A), while the installation direction of the regeneration one-way solenoid valve 71A is opposite to the regeneration flushing airflow direction (from drying tower B to drying tower A), and can achieve the same effect.

[0030] As one implementation method, such as Figure 1 As shown, the pressure boosting control assembly 8 includes a pressure boosting one-way solenoid valve 81A (or a pressure boosting one-way solenoid valve 81B, or a pressure boosting one-way solenoid valve 81C). The inlets of each of the pressure boosting one-way solenoid valves 81A, 81B, and 81C are connected, or the outlets of each of the pressure boosting one-way solenoid valves 81A, 81B, and 81C are connected. For example, when the common points of the pressure boosting one-way solenoid valves 81A, 81B, and 81C all correspond to the inlets of the pressure boosting one-way solenoid valves 81A, 81B, and 81C, reverse conduction problems caused by the outlet pressure being higher than the inlet pressure when a single one-way solenoid valve is in the closed state can be avoided.

[0031] Specifically, such as Figure 1As shown, when the drying tower A is in the pressure boosting state, one pressure boosting route is that the pressure boosting one-way electromagnetic valves 81C and 81A are opened, and the hydrogen gas at the outlet of the drying tower C enters the drying tower A in the reverse direction through the pressure boosting throttle 82C, the pressure boosting one-way electromagnetic valve 81C, the pressure boosting one-way electromagnetic valve 81A, and the pressure boosting throttle 82A. The installation directions of the one-way electromagnetic valves 81C and 81A are opposite, that is, the installation direction of one electromagnetic valve is the same as the gas flow direction in the pipeline, and the installation direction of the other electromagnetic valve is opposite to the gas flow direction in the pipeline. This can avoid the reverse conduction problem of a single one-way electromagnetic valve when it is in the closed state due to the outlet pressure being higher than the inlet pressure. The specific reason is similar to the above description, and will not be described here.

[0032] As an implementation mode, as shown in Figure 1 As shown, the regeneration control assembly 7 further comprises a regeneration throttle 73A (or a regeneration throttle 73B, or a regeneration throttle 73C), and the pressure boosting control assembly 8 further comprises a pressure boosting throttle 82A (or a pressure boosting throttle 82B, or a pressure boosting throttle 82C). The pressure boosting throttle 82A, the pressure boosting throttle 82B, and the pressure boosting throttle 82C have the same throttling diameter, so that when the drying tower 6 is in the pressure boosting process, the gas flow rate can be kept stable when the gas flow passes through any two pressure boosting pipelines 5. Among them, the throttling diameter of the pressure boosting throttle 82A is greater than that of the regeneration throttle 73A, the throttling diameter of the pressure boosting throttle 82B is greater than that of the regeneration throttle 73B, and the throttling diameter of the pressure boosting throttle 82C is greater than that of the regeneration throttle 73C. For the drying tower 6 in the pressure boosting step, a part of the product gas is boosted through the regeneration pipeline 4, and a larger part of the product gas is boosted through the pressure boosting pipeline 5, so that the two routes of product gas realize rapid pressure boosting of the drying tower 6.

[0033] As an implementation mode, as shown in Figure 1 As shown, the second pipeline 62 and the product gas output pipeline 2 are communicated through a check valve 9A (or a check valve 9B, or a check valve 9C). After the raw gas is adsorbed by the adsorbent in the drying tower 6, the dried hydrogen gas is introduced into the product gas output pipeline 2 through the check valve 9A (or the check valve 9B, or the check valve 9C), so as to avoid the backflow of the product gas.

[0034] As an implementation mode, as shown in Figure 1 As shown, the first pipeline 61 and the raw gas input pipeline 1 are communicated through an input electromagnetic valve 10A (or an input electromagnetic valve 10B, or an input electromagnetic valve 10C), and the first pipeline 61 and the waste gas output pipeline 3 are communicated through an output electromagnetic valve 11A (or an output electromagnetic valve 11B, or an output electromagnetic valve 11C).

[0035] As an implementation mode, as shown in Figure 1As shown, the outlet end of the product gas output pipeline 2 is provided with a pre-valve pressure regulating valve 12. By setting the set value of the pre-valve pressure regulating valve 12, the working pressure of the drying system can be ensured, so that the system works more stably.

[0036] The present application also provides a drying method, which provides the above-mentioned pressure swing adsorption type hydrogen drying system, and the three drying towers 6 respectively undergo repeated cycle steps to dry hydrogen by pressure swing adsorption. The repeated cycle steps undergone by each drying tower 6 are in turn an adsorption step, a pressure reduction step, a regeneration step, and a pressure increase step.

[0037] As an embodiment, the adsorption step is that the raw gas is sequentially transported to the drying tower 6 through the raw gas input pipeline 1 and the first pipeline 61, and after the water vapor is adsorbed by the adsorbent in the drying tower 6, the dried product gas flows out through the second pipeline 62 and the product gas output pipeline 2, and the content of water vapor in the product gas is less than 2 ppm.

[0038] As an embodiment, the pressure reduction step includes a forward pressure reduction step, a pressure maintaining step, and a reverse pressure reduction step. The forward pressure reduction step is that the high-pressure gas in the drying tower 6 flows out along the gas flow direction during adsorption to provide flushing high-pressure gas for regenerating the drying tower 6. The pressure maintaining step is that the drying tower 6 maintains a constant pressure state after the end of the forward pressure reduction step. The reverse pressure reduction step is that the remaining gas in the drying tower 6 flows out through the first pipeline 61 and the waste gas output pipeline 3 against the gas flow direction during adsorption.

[0039] As an embodiment, the regeneration step includes a first regeneration step and a second regeneration step. The first regeneration step is to use high-pressure gas to flush the drying tower 6 for the first time against the gas flow direction during adsorption through the second pipeline 62. The second regeneration step is to use product gas to flush the drying tower 6 for the second time against the gas flow direction during adsorption through the second pipeline 62.

[0040] As an embodiment, the pressure increase step includes two paths. One is that a part of the product gas enters the drying tower 6 against the gas flow direction during adsorption through the pressure increase pipeline 5. The other is that a part of the product gas enters the drying tower 6 against the gas flow direction during adsorption through the regeneration pipeline 4. In this embodiment, the drying tower 6 is simultaneously pressurized through the two paths, and rapid pressure increase is realized.

[0041] As an embodiment, the outlet end of the product gas output pipeline 2 is provided with a pre-valve pressure regulating valve 12, and the set value of the pre-valve pressure regulating valve 12 is 4 MPa, so as to ensure that the working pressure of the drying system is 4 MPa.

[0042] Example One:

[0043] The hydrogen gas generated by the electrolytic cell removes water droplets through a gas-liquid separator, and then enters a hydrogen drying tower 6 to remove water vapor in the hydrogen gas. The content of water vapor in the hydrogen gas passing through the drying tower 6 is less than 2 ppm. A valve before pressure regulating valve 12 is arranged on the product gas output pipeline of the drying system, and the set value of the valve before pressure regulating valve 12 is 4 MPa, so as to ensure that the working pressure of the drying system is 4 MPa. After the system is started and runs for a period of time to enter a stable running state, the running process step sequence table is shown in Table 1:

[0044] Table 1: Running process step sequence table of example one

[0045]

[0046] ① Time period T1 is set to 0-20s, the drying tower A is in the first regeneration process (regeneration 1), the drying tower B just ends the adsorption process, and the drying tower C is in the adsorption process. At this time, the input electromagnetic valve 10C is input, the output electromagnetic valve 11A is output, the regeneration one-way electromagnetic valves 71A and 72A are in the open state, and the remaining electromagnetic valves are in the off state. The raw material gas (moist hydrogen) generated by electrolysis enters the drying tower C through the input electromagnetic valve 10C, and after the water vapor is adsorbed by the adsorbent, the dried hydrogen gas is output through the product gas output pipeline 2 through the check valve 9C. The drying tower B just ends the adsorption process, and part of the dried hydrogen gas does not discharge from the drying tower B. The high-pressure dried hydrogen gas in the gap of the adsorbent in the drying tower B flows out of the drying tower B along the gas flow direction during adsorption, and the drying tower B is in a forward pressure reduction state (forward reduction). The high-pressure dried hydrogen gas enters the drying tower A in the reverse direction (reverse direction) through the regeneration one-way electromagnetic valves 72A and 71A and the regeneration throttle 73A, and the adsorbent in the drying tower A is regenerated for the first time. Then, the output electromagnetic valve 11A is used to discharge the moist hydrogen gas. Among them, the regeneration one-way electromagnetic valve 71A and the regeneration one-way electromagnetic valve 72A are opened and closed at the same time, and the installation directions are opposite, so as to avoid the reverse conduction problem caused by the outlet pressure being higher than the inlet pressure when a single electromagnetic valve is in the off state.

[0047] ② Run to time period T2, which is 20-40s, the drying tower A is in the second regeneration process (regeneration 2), the drying tower B remains in the pressure maintaining process (maintaining) after the forward reduction, and the drying tower C is in the adsorption process. The regeneration one-way electromagnetic valves 71A and 72A are closed, and the regeneration one-way electromagnetic valves 71C and 72C are opened at the same time. The product gas (dried hydrogen gas) generated by the adsorption of the drying tower C is used to regenerate the adsorbent in the drying tower A for the second time.

[0048] ③Run to time period T3, for 40-60s, the drying tower A is regenerated, the output solenoid valve 11A is closed, the output solenoid valve 11B, the boost one-way solenoid valve 81A, the boost one-way solenoid valve 81C are opened, the drying tower A enters the boost process, the two paths of boost are opened simultaneously, one is that the drying tower C outlet hydrogen passes through the regeneration throttle 73C, the regeneration one-way solenoid valve 71C and 72C and enters the drying tower A reversely, the other is that the drying tower C outlet hydrogen passes through the boost throttle 82C, the boost one-way solenoid valve 81C, the boost one-way solenoid valve 81A, the boost throttle 82A and enters the drying tower A reversely.The throttle diameters of the boost throttles 82A, 82B and 82C are same and greater than the throttle diameters of the regeneration throttles 73A, 73B and 73C, so the fast boost of the drying tower A can be realized.Similarly, the common points of the boost one-way solenoid valves 81A, 81B and 81C all correspond to the inlets of solenoid valves, so the reverse conduction problem of a single solenoid valve when it is in the closed state due to the outlet pressure being higher than the inlet pressure is avoided.The dryer B is in the reverse pressure reduction state (reverse reduction), after the output solenoid valve 11B is opened, the remaining gas in the dryer B flows out reversely, is discharged from the system through the waste gas output pipeline 3.

[0049] ④Run to time period T4, for 60-80s, the drying tower A is in the adsorption state, the drying tower B is in the regeneration 1 state, and the drying tower C is in the normal reduction state.The running sequence table is seen in sequence, and the sequence 1-9 is repeated.

[0050] The variable pressure adsorption type hydrogen drying system provided by the application adopts the structure of three drying towers 6, controls the opening and closing of each pipeline, uses the high-pressure dried hydrogen in the drying tower 6 at the end of the adsorption process to perform primary regeneration on the drying tower 6 about to start regeneration, and then uses the dried product hydrogen to perform subsequent regeneration, so that the amount of product hydrogen is saved, and hydrogen is saved.Further, by arranging two one-way solenoid valves with opposite installation directions in the regeneration pipeline 4 and the boost pipeline 5, and simultaneously opening and closing, the reverse conduction problem of a single solenoid valve when it is in the closed state due to the outlet pressure being higher than the inlet pressure is avoided, and the running stability of the system is improved.

[0051] The above is only a preferred embodiment of the application, and does not limit the application in any form. Although the application has been disclosed as above with a preferred embodiment, it is not intended to limit the application. Any person skilled in the art can make some changes or modifications to the disclosed technical content without departing from the technical solution range of the application, and equivalent embodiments with equivalent changes are obtained. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the application are still within the protection range of the technical solution of the application.

Claims

1. A pressure swing adsorption (PSA) hydrogen drying system, characterized in that, The application relates to a pressure swing adsorption type hydrogen drying system, which comprises three drying towers (6), a raw gas input pipeline (1), a product gas output pipeline (2), a waste gas output pipeline (3), first pipelines (61) and second pipelines (62) which are arranged at opposite ends of each drying tower (6) and are in communication with the interiors of the drying towers (6), each first pipeline (61) is in communication with the raw gas input pipeline (1) and the waste gas output pipeline (3), each second pipeline (62) is in communication with the product gas output pipeline (2), any two second pipelines (62) are in communication through a regeneration pipeline (4), one second pipeline (62) is correspondingly connected with a pressure boosting pipeline (5), the pressure boosting pipelines (5) are in communication with each other, a regeneration control assembly (7) is arranged on each regeneration pipeline (4), and a pressure boosting control assembly (8) is arranged on each pressure boosting pipeline (5). Each regeneration control assembly (7) comprises two regeneration one-way electromagnetic valves, and the installation directions of the two regeneration one-way electromagnetic valves are opposite. Each pressure boosting control assembly (8) comprises a pressure boosting one-way electromagnetic valve, the inlets of the pressure boosting one-way electromagnetic valves are connected with each other, or the outlets of the pressure boosting one-way electromagnetic valves are connected with each other. The regeneration control assembly (7) further comprises a regeneration flow restrictor, the pressure boosting control assembly (8) further comprises a pressure boosting flow restrictor, the flow restrictor diameters of the pressure boosting flow restrictors are the same, and the flow restrictor diameters of the pressure boosting flow restrictors are larger than the flow restrictor diameters of the regeneration flow restrictors.

2. The pressure swing adsorption hydrogen drying system of claim 1, wherein, The second pipeline (62) and the product gas output pipeline (2) are in communication through a check valve.

3. The pressure swing adsorption hydrogen drying system of claim 1, wherein, The first pipeline (61) and the raw gas input pipeline (1) are in communication through an input electromagnetic valve, and the first pipeline (61) and the waste gas output pipeline (3) are in communication through an output electromagnetic valve.

4. The pressure swing adsorption hydrogen drying system of claim 1, wherein, The outlet end of the product gas output pipeline (2) is provided with a pre-valve pressure regulating valve (12).

5. A drying method characterized by, The application further provides the pressure swing adsorption type hydrogen drying system, and three drying towers (6) are used to perform pressure swing adsorption drying of hydrogen through repeated circulation steps, and each drying tower (6) sequentially experiences an adsorption step, a pressure reduction step, a regeneration step and a pressure boosting step. The pressure reduction step comprises a forward pressure reduction step, a pressure maintaining step and a reverse pressure reduction step, the forward pressure reduction step is that high-pressure gas in the drying tower (6) flows out along the gas flow direction during adsorption to provide flushing high-pressure gas for the regenerated drying tower (6), the pressure maintaining step is that the drying tower (6) maintains constant pressure after the forward pressure reduction step, and the reverse pressure reduction step is that residual gas in the drying tower (6) is discharged through the first pipeline (61) and the waste gas output pipeline (3) against the gas flow direction during adsorption. The regeneration step comprises a first regeneration step and a second regeneration step, the first regeneration step is that high-pressure gas is used to flush the drying tower (6) for the first time against the gas flow direction during adsorption, and the second regeneration step is that product gas is used to flush the drying tower (6) for the second time against the gas flow direction during adsorption. The pressure boosting step includes two paths, one of which is that a part of product gas enters the drying tower (6) against the gas flow direction during adsorption through the pressure boosting pipeline (5), and the other of which is that a part of product gas enters the drying tower (6) against the gas flow direction during adsorption through the regeneration pipeline (4).

6. The drying method according to claim 5, wherein The adsorption step is that raw gas is sequentially conveyed through the raw gas input pipeline (1), the first pipeline (61) to the drying tower (6), and discharged after water vapor is adsorbed by the adsorbent in the drying tower (6), and the content of water vapor in product gas is less than 2 ppm.

7. The drying method according to claim 5, wherein The outlet end of the product gas output pipeline (2) is provided with a pre-valve pressure regulating valve (12), and the set value of the pre-valve pressure regulating valve (12) is 4 MPa.

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