Pure hydrogen preparation system capable of recycling impurity hydrogen

Abstract

The utility model relates to the technical field of hydrogen preparation, in particular to a pure hydrogen preparation system capable of recycling impurity hydrogen, which is technically characterized by further comprising an impurity hydrogen recycling system, and the impurity hydrogen recycling system comprises a gas intercepting part and a purging part, the gas interception part is communicated with the tail gas emission end of the target membrane purifier, the purging part comprises a rectangular annular pipeline, and the two ends of the annular pipeline in the length direction extend towards a molecular sieve target catalyst system respectively and are communicated with the molecular sieve target catalyst system; and purging one-way valves are arranged on the edges of the two ends of the annular pipeline in the length direction, the purging one-way valves point to and deviate from the molecular sieve target catalyst system, and the length edge of the end, deviating from the molecular sieve target catalyst system, of the annular pipeline is communicated with an exhaust hole. When the system works, the recycled purge gas can heat the molecular sieve, so that the regeneration effect is improved, and the service life of the molecular sieve is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of hydrogen preparation, in particular to a pure hydrogen preparation system for recycling impure hydrogen. Background Art

[0002] When preparing ultra-high-purity hydrogen, two different purification methods are usually used. One is to purify hydrogen through a molecular sieve palladium catalyst to increase the purity to 99.999%. This purification system generally has two cylinders, which use the principle of pressure swing adsorption for alternating regeneration, so that the molecular sieve can be reused. This regeneration method will result in about 5% purge gas waste. The other method is to pass hydrogen with a purity of more than 99.99% into a palladium membrane purifier to increase its purity to more than 99.99999%. This system needs to discharge the intercepted impurity gas of about 5%. When ultra-high-purity hydrogen needs to be prepared, the two purification methods need to be connected in series, and the total hydrogen waste may exceed 10%. Utility Model Content

[0003] Therefore, the technical problem to be solved by the present invention is that when preparing ultra-high purity hydrogen in the prior art, there is a waste of hydrogen.

[0004] The above technical objectives of the present invention are achieved through the following technical solutions:

[0005] A pure hydrogen preparation system for recycling impure hydrogen includes a molecular sieve target catalyst system, a target membrane purification system, and an impurity hydrogen recycling system, wherein the impurity hydrogen recycling system is located between the molecular sieve target catalyst system and the target membrane purification system, and the impurity hydrogen recycling system includes a gas interception part and a purge part, wherein the gas interception part is connected to the tail gas discharge end of the target membrane purifier, and the purge part includes an annular pipe arranged in a rectangular shape, and the two ends of the annular pipe in the length direction respectively extend toward the molecular sieve target catalyst system and are connected to the molecular sieve target catalyst system; purge one-way valves are provided on the edges of the two ends in the length direction of the annular pipe, and the purge one-way valves are arranged to point away from the molecular sieve target catalyst system, and the length side of the annular pipe at one end away from the molecular sieve target catalyst system is connected to the exhaust hole.

[0006] Preferably, the molecular sieve target catalyst system includes a first air intake part, a purification cylinder, a plurality of solenoid valves, a catalyst pipeline and a first exhaust part, wherein the first air intake part and the purification cylinder and the purification cylinder and the first exhaust part are connected through catalyst pipelines respectively, and the catalyst pipelines are respectively a first catalyst pipeline and a second catalyst pipeline, wherein the first catalyst pipeline is used to connect the first air intake part and the purification cylinder, and the second catalyst pipeline is used to connect the first exhaust part and the purification cylinder.

[0007] Preferably, there are two purification cylinders, one end of the first catalyst pipe is connected to the first air intake part, and the other end is divided into two sections and respectively connected to the two purification cylinders, and an air intake solenoid valve is respectively provided on the two separated sections of the first catalyst pipe.

[0008] Preferably, the target membrane purification system includes a second air inlet, a heat exchanger, a target membrane purifier, a plurality of exhaust ports and a plurality of purification pipelines, wherein the purification pipelines are used to connect the various components of the target membrane purification system; two heat exchangers are provided, and four exhaust ports are provided, and the four exhaust ports are respectively a first exhaust port, a second exhaust port, a third exhaust port and a fourth exhaust port.

[0009] Preferably, two heat exchangers are provided, the two heat exchangers are a first heat exchanger and a second heat exchanger, the two heat exchangers are respectively connected to the second air intake part, an air intake pipe extends from the second air intake part, the air intake pipe is divided into two sections pointing to one end of the heat exchanger and is respectively connected to the two heat exchangers, the first heat exchanger is connected to the third exhaust port and the fourth exhaust port, and the third exhaust port is provided with a first solenoid valve.

[0010] Preferably, two openings on the second heat exchanger are connected to the second exhaust port and the fourth exhaust port, wherein a first manual needle valve, a first pressurizing valve and an exhaust one-way valve are sequentially provided on the pipe connecting the second heat exchanger and the second exhaust port; the exhaust port of the target membrane purifier is respectively connected to the two heat exchangers.

[0011] Preferably, the gas interception part includes a gas pipeline, and the connection position of the gas pipeline and the heat exchanger is between the heat exchanger and the first manual needle valve. A second solenoid valve is provided on the gas pipeline. The gas pipeline is divided into two sections after passing through the second solenoid valve, one section is connected to the first exhaust port, and the other section points to the purge part and is connected to the purge part. A third solenoid valve is provided between the gas pipeline and the purge part, the air inlet end of the target membrane purifier is connected to the gas pipeline, and the connection section of the gas pipeline and the target membrane purifier is located between the third solenoid valve and the purge part.

[0012] Preferably, a fourth solenoid valve, a first one-way valve, a back pressure valve, a second pressure reducing valve and a heating device are sequentially provided on the connecting section between the gas pipeline and the target membrane purifier from the third solenoid valve to the target membrane purifier.

[0013] Preferably, both ends of the annular pipe in the length direction extend toward the purification cylinder and are connected to the purification cylinder, and a pressure sensor is provided on the pipe connecting the annular pipe and the purification cylinder respectively; a purge one-way valve is provided on the edges of both ends in the length direction of the annular pipe, and the purge one-way valve points away from the purification cylinder. The purge part also includes a first pipe extending from the first heat exchanger, and the first pipe points to the middle position of the length side of the annular pipe. The first pipe is provided with an exhaust gas one-way valve, and the exhaust gas one-way valve controls the exhaust gas from the target membrane purifier to flow toward the annular pipe after being discharged. The connection point between the first pipe and the annular pipe is located in the middle position of the side of the annular pipe pointing to the purification cylinder, and two third one-way valves are provided on the length side of the annular pipe pointing to the purification cylinder. The two third one-way valves are set to point away from each other and are located on both sides of the first pipe.

[0014] Compared with the existing technology, this application has the following beneficial effects:

[0015] During the hydrogen production process, when the pressure of the pressure sensor is less than 0.3Mpa, the first solenoid valve is closed, and the tail gas of the target membrane purifier enters the purge part through the tail gas one-way valve to assist in purge. The application scenario of the pure hydrogen preparation system for recycling impurity hydrogen provided by this application is a PEM ultra-high purity hydrogen production system of less than 10 standard cubic meters. In the hydrogen production system, small standard cubic meter systems usually use PSA. Since the amount of ultra-high purity hydrogen used is relatively small at a relatively low pressure, only a part of the purge gas can be reused; and this system is suitable for equipment that uses a palladium membrane hydrogen purifier in combination with a PSA purifier. The purity of the hydrogen gas at the outlet of the PSA purifier is 99.999%, and the air intake requirement of the palladium membrane purifier is above 99.99%. The impurities in the impurity gas are mainly water vapor, which has no effect on the molecular sieve and meets the purge requirements.

[0016] When the system is working, the recycled purge gas will heat the molecular sieve, improve the regeneration effect and extend the service life of the molecular sieve. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an overall structural diagram of a pure hydrogen preparation system for recycling impurity hydrogen in one embodiment of the present invention.

[0018] In the figure, 1. molecular sieve target catalyst system; 11. first air inlet; 12. purification cylinder; 13. first catalyst pipeline; 14. second catalyst pipeline; 15. first exhaust; 16. exhaust solenoid valve; 17. intake solenoid valve; 2. target membrane purification system; 21. second air inlet; 211. intake pipeline; 221. first heat exchanger; 222. second heat exchanger; 23. target membrane purifier; 24. purification pipeline; 25. first exhaust port; 26. second exhaust port; 261. first manual needle valve; 262. first pressurizing valve; 263. exhaust one-way valve Valve; 27, third exhaust port; 271, first solenoid valve; 28, fourth exhaust port; 3, impurity hydrogen recycling system; 31, gas interception part; 311, gas pipeline; 3111, fourth solenoid valve; 3112, first one-way valve; 3113, back pressure valve; 3114, second pressure reducing valve; 3115, heating device; 312, second solenoid valve; 313, third solenoid valve; 32, purge part; 321, annular pipeline; 3211, second manual needle valve; 322, pressure sensor; 323, purge one-way valve; 324, first pipeline; 325, third one-way valve; 326, exhaust one-way valve. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0020] See also Figure 1 A pure hydrogen preparation system for recycling impure hydrogen includes a molecular sieve target catalyst system 1, a target membrane purification system 2, and an impure hydrogen recycling system 3. The impurity hydrogen recycling system 3 is located between the molecular sieve target catalyst system 1 and the target membrane purification system 2, and is used to reuse the impurity gas intercepted in the target membrane purification system 2.

[0021] In one embodiment, see Figure 1 The molecular sieve target catalyst system 1 includes a first air intake part 11, a purification cylinder 12, a plurality of solenoid valves, a catalyst pipeline and a first exhaust part 15, wherein the first air intake part 11 and the purification cylinder 12 and the purification cylinder 12 and the first exhaust part 15 are respectively connected through catalyst pipelines. In one embodiment, the catalyst pipelines are respectively a first catalyst pipeline 13 and a second catalyst pipeline 14, wherein the first catalyst pipeline 13 is used to connect the first air intake part 11 and the purification cylinder 12, and the second catalyst pipeline 14 is used to connect the first exhaust part 15 and the purification cylinder 12.

[0022] In one embodiment, two purification cylinders 12 are provided. One end of the first catalyst pipe 13 is connected to the first air inlet 11, and the other end is divided into two sections and respectively connected to the two purification cylinders 12. An air intake solenoid valve 17 is provided on each of the two separated sections of the first catalyst pipe 13.

[0023] The second catalyst pipe 14 is used to connect the first exhaust part 15 and the purification cylinder 12. One end of the second catalyst pipe 14 is connected to the first exhaust part 15, and the other end of the second catalyst pipe 14 is divided into two sections and is respectively connected to the purification cylinder 12. The connection position between the second catalyst pipe 14 and the purification cylinder 12 is located between the purification cylinder 12 and the intake solenoid valve 17. Exhaust solenoid valves 16 are respectively provided on the second catalyst pipe 14 between the separation points of the first catalyst pipe 13 and the second catalyst pipe 14.

[0024] See also Figure 1 The target membrane purification system 2 includes a second air inlet 21, a heat exchanger, a target membrane purifier 23, several exhaust ports, and several purification pipelines 24. The purification pipelines 24 are used to connect the various components of the target membrane purification system 2. There are two heat exchangers and four exhaust ports, namely a first exhaust port 25, a second exhaust port 26, a third exhaust port 27, and a fourth exhaust port 28.

[0025] See also Figure 1 , there are two heat exchangers, namely a first heat exchanger 221 and a second heat exchanger 222, and the two heat exchangers are respectively connected to the second air intake portion 21. In one embodiment, an air intake pipe 211 extends from the second air intake portion 21, and the air intake pipe 211 is divided into two sections at one end pointing to the heat exchanger and is respectively connected to the two heat exchangers. The first heat exchanger 221 is connected to the third exhaust port 27 and the fourth exhaust port 28. In one embodiment, a first solenoid valve 271 is provided on the third exhaust port 27;

[0026] Two openings on the second heat exchanger 222 are connected to the second exhaust port 26 and the fourth exhaust port 28, wherein a first manual needle valve 261, a first pressurizing valve 262 and an exhaust one-way valve 263 are sequentially provided on the pipeline connecting the second heat exchanger 222 and the second exhaust port 26.

[0027] The exhaust port of the target membrane purifier 23 is connected to the two heat exchangers respectively.

[0028] The impurity hydrogen recycling system 3 comprises a gas intercepting part 31 and a purging part 32. The gas intercepting part 31 is arranged in communication with the tail gas discharge end of the target film purifier 23. In an embodiment, the gas intercepting part 31 comprises a gas pipeline 311, which is connected to the heat exchanger between the heat exchanger and the first manual needle valve 261. The gas pipeline 311 is provided with a second electromagnetic valve 312. The gas pipeline 311 is divided into two sections after the second electromagnetic valve 312. One section is arranged in communication with the first exhaust port 25, and the other section is directed to the purging part 32 and arranged in communication with the purging part 32. The gas pipeline 311 is provided with a third electromagnetic valve 313 between the purging part 32. In an embodiment, the gas pipeline 311 is arranged in communication with the gas inlet end of the target film purifier 23. The connection section of the gas pipeline 311 and the target film purifier 23 is located between the third electromagnetic valve 313 and the purging part 32. In an embodiment, the connection section of the gas pipeline 311 and the target film purifier 23 is sequentially provided with a fourth electromagnetic valve 3111, a first check valve 3112, a back pressure valve 3113, a second pressure reducing valve 3114 and a heating device 3115 between the third electromagnetic valve 313 and the target film purifier 23.

[0029] The purging part 32 comprises a substantially rectangular annular pipeline 321, as shown in Figure 1 The annular pipeline 321 is arranged in communication with the purification cylinder 12 at both ends in the length direction. A pressure sensor 322 is arranged on the pipeline in communication with the purification cylinder 12. The annular pipeline 321 is provided with a purging check valve 323 at the edges of both ends in the length direction. The purging check valve 323 is arranged to face away from the purification cylinder 12. The purging part 32 further comprises a first pipeline 324 extending from the first heat exchanger 221. The first pipeline 324 is directed to the middle position of the length side of the annular pipeline 321. The first pipeline 324 is provided with a tail gas check valve 326. The tail gas check valve controls the tail gas discharged from the target film purifier 23 to flow to the annular pipeline 321. In an embodiment, the connection point of the first pipeline 324 and the annular pipeline 321 is located at the middle position of the side of the annular pipeline 321 facing the purification cylinder 12. The length side of the annular pipeline 321 facing the purification cylinder 12 is provided with two third check valves 325. The two third check valves 325 are arranged to face away from each other and located on both sides of the first pipeline 324.

[0030] The annular pipe 321 is connected to the gas pipe 311, and the connection point between the annular pipe 321 and the gas pipe 311 is located in the middle position of the length side of the annular pipe 321 away from the purification cylinder 12. In addition, a second manual needle valve 3211 is also provided between the two length sides of the annular pipe 321, and the second manual needle valve 3211 points in the direction of the purification cylinder 12.

[0031] In this application, the impurity gas intercepted by the palladium membrane purifier is reused and passed into the regeneration cylinder of the pressure swing adsorption equipment to assist in purging, thereby helping it to quickly increase the pressure and reduce the hydrogen waste of the system.

[0032] During the operation of the palladium membrane purification system, the purification cylinder 12 needs to be heated to 300°C. Therefore, when the gas is passed into the regeneration cylinder of the pressure swing adsorption equipment without cooling, the thermal energy can be utilized to heat the molecular sieve, thereby enhancing the regeneration effect of the entire regeneration cylinder and extending its working cycle.

[0033] Specifically, during the hydrogen production process, when the pressure of the pressure sensor 322 is less than 0.3Mpa, the first solenoid valve 271 is closed, and the tail gas of the target membrane purifier 23 enters the purge section 32 through the tail gas one-way valve to assist in purge. The application scenario of the pure hydrogen preparation system for recycling impurity hydrogen provided by the present application is a PEM ultra-high purity hydrogen production system of less than 10 standard cubic meters. In the hydrogen production system, small standard cubic meter systems usually use PSA. Since the amount of ultra-high purity hydrogen used is relatively small at a relatively low pressure, only a part of the purge gas can be reused; and this system is suitable for equipment that uses a palladium membrane hydrogen purifier in combination with a PSA purifier. The purity of the hydrogen gas at the outlet of the PSA purifier is 99.999%, and the air intake requirement of the palladium membrane purifier is above 99.99%. The impurities in the impurity gas are mainly water vapor, which has no effect on the molecular sieve and meets the purge requirements.

[0034] When the system is working, the recycled purge gas will heat the molecular sieve, improve the regeneration effect and extend the service life of the molecular sieve.

Claims

1. A pure hydrogen production system for recycling impure hydrogen, comprising a molecular sieve target catalyst system and a target membrane purification system, characterized in that: The invention also includes an impurity hydrogen recycling system, which is located between the molecular sieve target catalyst system and the target membrane purification system. The impurity hydrogen recycling system includes a gas interception part and a purge part. The target membrane purification system includes a second air inlet, a heat exchanger, a target membrane purifier, a plurality of exhaust ports, and a plurality of purification pipelines. The purification pipelines are used to connect the various components of the target membrane purification system. There are two heat exchangers and four exhaust ports, which are respectively a first exhaust port, a second exhaust port, a third exhaust port, and a fourth exhaust port. The gas interception part is connected to the tail gas discharge end of the target membrane purifier. The purge part includes a rectangular annular pipe, the longitudinal ends of which extend toward the molecular sieve target catalyst system and are connected to the molecular sieve target catalyst system. Purge check valves are provided on the longitudinal edges of the annular pipe, and the purge check valves are arranged to point away from the molecular sieve target catalyst system. The longitudinal side of the annular pipe at one end away from the molecular sieve target catalyst system is connected to the exhaust port.

2. The pure hydrogen production system for recycling impure hydrogen according to claim 1, characterized in that: The molecular sieve target catalyst system includes a first air intake part, a purification cylinder, several solenoid valves, a catalyst pipeline and a first exhaust part, wherein the first air intake part and the purification cylinder and the purification cylinder and the first exhaust part are respectively connected through catalyst pipelines, and the catalyst pipelines are respectively a first catalyst pipeline and a second catalyst pipeline, wherein the first catalyst pipeline is used to connect the first air intake part and the purification cylinder, and the second catalyst pipeline is used to connect the first exhaust part and the purification cylinder.

3. The pure hydrogen production system for recycling impure hydrogen according to claim 2, characterized in that: There are two purification cylinders. One end of the first catalyst pipe is connected to the first air intake part, and the other end is divided into two sections and respectively connected to the two purification cylinders. An air intake solenoid valve is respectively provided on the two separated sections of the first catalyst pipe.

4. The pure hydrogen production system for recycling impure hydrogen according to claim 3, characterized in that: There are two heat exchangers, which are the first heat exchanger and the second heat exchanger. The two heat exchangers are respectively connected to the second air intake part. An air intake pipe extends from the second air intake part. The air intake pipe is divided into two sections at one end pointing to the heat exchanger and is respectively connected to the two heat exchangers. The first heat exchanger is connected to the third exhaust port and the fourth exhaust port, and the third exhaust port is provided with a first solenoid valve.

5. The pure hydrogen production system for recycling impure hydrogen according to claim 4, characterized in that: Two openings on the second heat exchanger are connected to the second exhaust port and the fourth exhaust port, wherein a first manual needle valve, a first pressurizing valve and an exhaust one-way valve are sequentially provided on the pipe connecting the second heat exchanger and the second exhaust port; the exhaust port of the target membrane purifier is respectively connected to the two heat exchangers.

6. The pure hydrogen production system for recycling impure hydrogen according to claim 5, characterized in that: The gas interception part includes a gas pipeline, and the connection position between the gas pipeline and the heat exchanger is between the heat exchanger and the first manual needle valve. A second solenoid valve is provided on the gas pipeline. The gas pipeline is divided into two sections after passing through the second solenoid valve, one section is connected to the first exhaust port, and the other section points to the purge part and is connected to the purge part. A third solenoid valve is provided between the gas pipeline and the purge part, the air inlet end of the target membrane purifier is connected to the gas pipeline, and the connection section of the gas pipeline and the target membrane purifier is located between the third solenoid valve and the purge part.

7. The pure hydrogen production system for recycling impure hydrogen according to claim 6, characterized in that: A fourth solenoid valve, a first one-way valve, a back pressure valve, a second pressure reducing valve and a heating device are sequentially arranged on the connecting section between the gas pipeline and the target membrane purifier from the third solenoid valve to the target membrane purifier.

8. The pure hydrogen production system for recycling impure hydrogen according to claim 7, characterized in that: The two ends of the annular pipe in the length direction extend toward the purification cylinder and are connected to the purification cylinder, and a pressure sensor is provided on the pipe connecting the annular pipe and the purification cylinder respectively; a purge one-way valve is provided on the edges of the two ends of the length direction of the annular pipe, and the purge one-way valve points away from the purification cylinder. The purge part also includes a first pipe extending from the first heat exchanger, the first pipe points to the middle position of the length side of the annular pipe, and the exhaust gas one-way valve is provided on the first pipe. The exhaust gas one-way valve controls the exhaust gas from the target membrane purifier to flow toward the annular pipe after being discharged. The connection point between the first pipe and the annular pipe is located in the middle position of the side of the annular pipe pointing to the purification cylinder, and two third one-way valves are provided on the length side of the annular pipe pointing to the purification cylinder. The two third one-way valves are set to point away from each other and are located on both sides of the first pipe.

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