Water electrolysis hydrogen production condensate recycling system

Abstract

The utility model discloses a water electrolysis hydrogen production condensate recycling system. The system comprises a hydrogen separation tank, a hydrogen drainage tank, an oxygen separation tank, an oxygen drainage tank, a water collection tank, an alkali liquor collection tank, a self-priming pump, a demineralized water buffer tank, an alkali liquor tank and the like, the hydrogen liquid separation tank, the hydrogen drainage tank and the water collection tank are sequentially connected through a pipeline, and the hydrogen drainage tank also collects wastewater discharged from other discharge points; the oxygen liquid separation tank, the oxygen drainage tank and the demineralized water buffer tank are sequentially connected through a pipeline; self-priming pumps are arranged at the upper parts of the water collecting tank and the alkali liquor collecting tank, and when the liquid level in the water collecting tank is higher than a certain liquid level, the self-priming pumps are automatically started to discharge recycled water into the demineralized water buffer tank; when the liquid level in the water collecting tank is lower than a certain liquid level, the self-priming pump is automatically closed; according to the system, nodes where condensate is possibly generated on the hydrogen side and the oxygen side are recycled, the hydrogen-oxygen mixing risk is reduced, and the consumption of raw material water is effectively reduced.

Description

Technical Field

[0001] The utility model belongs to the field of chemical industry and relates to a water electrolysis hydrogen production technology, in particular to a water electrolysis hydrogen production condensate recovery and utilization system. Background Art

[0002] The hydrogen and oxygen produced by the electrolyzer of the water electrolysis hydrogen production system are separated into gas and liquid in the separator. The separated hydrogen needs to go through washing, cooling, liquid separation, deoxygenation, drying and other processes to produce qualified products. Hydrogen will produce condensate during the cooling and deoxygenation process; the separated oxygen needs to go through washing, cooling and other processes, which will also produce condensate. Recycling the condensate produced on the hydrogen side and the oxygen side and recycling it back to the system for utilization can reduce the consumption of electrolyte and move towards the goal of "zero emission". However, in the process of recovering the condensate, the condensate on the hydrogen side and the oxygen side dissolves a small amount of hydrogen and oxygen respectively. Due to the wide explosion limit of hydrogen, the hydrogen condensate needs to be treated separately.

[0003] Patent CN201220440169.5 discloses a condensate recovery system for water electrolysis hydrogen production. By setting a liquid collector as a recovery transition and combining a controllable supplementary pressure system and control method, the condensate in the water electrolysis hydrogen production process can be recovered from the low-pressure side to the high-pressure side. By changing the on-off state of the control valve for multiple cycles, the problem that the condensate on the low-pressure side generated in the gas treatment process cannot flow back to the high-pressure side is solved, but the patent does not consider the recovery of the condensate in the gas-liquid separator.

[0004] Patent CN202020252214.9 discloses a hydrogen production condensate reflux differential pressure output system, which uses two regulating valves to control the hydrogen pressure to always be greater than the oxygen pressure, and can adjust the pressure difference between the two by adjusting the spring pressure, thereby realizing staggered collection of hydrogen and oxygen and automatic recovery of condensate. However, in the recovery process of this patent, a water-permeable diaphragm needs to be set in the hydrogen droplet collector, which has a complex structure and the supporting process control is also relatively complex.

[0005] Patent CN202111308745.0 discloses an emission liquid recovery system for an electrolytic hydrogen production device and a control method for the recovery system. The system can effectively recover the raw liquid entrained by the gas discharge out of the system, achieve zero emissions during the operation of the hydrogen production device, and reduce the amount of raw liquid replenishment. However, the patent does not consider the condensate on the hydrogen side and the condensate on the oxygen side separately, and there is a potential risk of mixing hydrogen and oxygen. Summary of the invention

[0006] In order to solve the technical problem in the prior art of how to conveniently, safely and efficiently recycle condensate in a water electrolysis hydrogen production device, the utility model provides a water electrolysis hydrogen production condensate recycling system.

[0007] The utility model provides a water electrolysis hydrogen production condensate recycling system, which comprises a hydrogen separator, a hydrogen drainage tank, an oxygen separator, an oxygen drainage tank, a water collection tank, an alkali liquid collection tank, a self-priming pump, a desalted water buffer tank, an alkali liquid tank, etc.; the hydrogen separator, the hydrogen drainage tank and the water collection tank are connected in sequence through pipelines, and the hydrogen drainage tank also collects waste water discharged from other discharge points; the oxygen separator, the oxygen drainage tank and the desalted water buffer tank are connected in sequence through pipelines; a self-priming pump is arranged on the upper part of the water collection tank and the alkali liquid collection tank, and when the liquid level in the water collection tank is higher than a certain liquid level, the self-priming pump is automatically started to discharge the recovered water into the desalted water buffer tank; when the liquid level in the water collection tank is lower than a certain liquid level, the self-priming pump is automatically closed; when the device is shut down, the waste alkali liquid from the discharge point such as the electrolytic cell can also be circulated back to the alkali liquid tank through the alkali liquid collection tank by the self-priming pump, and the water in the desalted water buffer tank and the alkali liquid in the alkali liquid tank are mixed and enter the electrolysis module.

[0008] As an improved solution, the liquid level in the water collecting tank is higher than a certain level when the liquid level reaches a level higher than 70%; the liquid level in the water collecting tank is lower than a certain level when the liquid level drops to a level lower than 20%.

[0009] As a further improved solution, a local liquid level meter and a remote liquid level meter are arranged on the hydrogen liquid separation tank, and the remote liquid level meter is provided with a high and low limit alarm function; a local liquid level meter and a remote liquid level meter are arranged on the hydrogen drainage tank, and the remote liquid level meter is provided with a high and low limit alarm function; a local pressure gauge and a remote pressure gauge as well as a high and low limit alarm function are arranged on the water collection tank, and a remote liquid level meter and a high and low limit alarm function are arranged.

[0010] As a further improved solution, a switch valve is set on the pipeline between the hydrogen liquid separator tank and the hydrogen drainage tank to control the liquid level in the hydrogen liquid separator tank; a liquid level control valve is set on the pipeline between the hydrogen drainage tank and the water collection tank to control the liquid level in the hydrogen drainage tank.

[0011] As a further improved solution, an interlocking shut-off valve is provided between the hydrogen drain tank and the hydrogen drain tank outlet liquid level control valve for use when the liquid level in the hydrogen drain tank is low. This can effectively prevent the risk of hydrogen entering the downstream system due to failure of the remote level gauge or the control valve.

[0012] As a further improved solution, an on-site pressure gauge and a remote pressure gauge as well as high and low limit alarm functions are installed on the top of the hydrogen drainage tank; at the same time, a nitrogen sealing system is set up, when the pressure of the hydrogen drainage tank is low, low-pressure nitrogen is added through a control valve, and when the pressure of the hydrogen drainage tank is high, it is discharged to the venting system through the control valve; at the same time, a safety relief facility is set on the top of the hydrogen drainage tank to play an overpressure protection role.

[0013] As a further improvement, a flame arrester is provided at the end of the venting system pipeline at the gas phase outlet of the water collection tank to prevent flashback after hydrogen combustion. In order to prevent air from being introduced into the system through the venting pipeline, a nitrogen purge replacement pipeline is provided at the top of the water collection tank, and a certain amount of nitrogen inflow is maintained by providing a flow limiting orifice plate or a control valve.

[0014] As a further improved solution, a local liquid level meter and a remote liquid level meter are arranged on the oxygen liquid separation tank, and the remote liquid level meter is provided with a high and low limit alarm function; a local liquid level meter and a remote liquid level meter are arranged on the oxygen drainage tank, and the remote liquid level meter is provided with a high and low limit alarm function; a local pressure gauge and a remote pressure gauge as well as a high and low limit alarm function are arranged on the alkali solution collection tank, and a remote liquid level meter and a high and low limit alarm function are arranged.

[0015] As a further improved solution, a switch valve is set on the pipeline between the oxygen separator tank and the oxygen drainage tank to control the liquid level in the oxygen separator tank; a liquid level control valve is set on the pipeline between the oxygen drainage tank and the desalted water buffer tank to control the liquid level in the oxygen drainage tank.

[0016] As a further improved solution, an interlocking shut-off valve is provided between the oxygen drain tank and the oxygen drain tank outlet liquid level control valve for use when the liquid level in the oxygen drain tank is low. This can effectively prevent the risk of oxygen entering the downstream system due to failure of the remote liquid level meter or the control valve.

[0017] The utility model has the following beneficial effects:

[0018] 1) The nodes that may produce condensate on the hydrogen side and the oxygen side are recycled and reused, effectively reducing the consumption of raw water.

[0019] 2) A hydrogen drainage tank is added downstream of the hydrogen separator tank, and is opened and closed by a switch valve, which effectively reduces the loss of hydrogen during the production process, and is also applicable to the oxygen side.

[0020] 3) The condensate produced on the hydrogen side and the oxygen side is recovered and treated separately to reduce the risk of hydrogen and oxygen mixing, which reflects the design concept of intrinsic safety.

[0021] 4) Liquid level or pressure detection, alarm, control and interlocking systems are set up at the hydrogen separator tank, hydrogen drainage tank and water collection tank on the hydrogen side to prevent the risk of hydrogen entering the downstream system. The same applies to the oxygen side.

[0022] 5) The hydrogen side is isolated from external oxygen by setting up a nitrogen sealing system and a nitrogen replacement system, thereby reducing the possibility of explosion caused by the mixture of hydrogen and oxygen. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1It is a schematic diagram of the process of the utility model.

[0024] In the figure: 1-hydrogen liquid separator, 2-switch valve a, 3-hydrogen drainage tank, 4-interlock valve b, 5-oxygen liquid separator, 6-switch valve d, 7-oxygen drainage tank, 8-interlock valve e, 9-water collection tank, 10-alkali solution collection tank, 11-self-priming pump, 12-flame arrester, 13-desalt water buffer tank, 14-alkali solution tank, 15-control valve c, 16-control valve f. DETAILED DESCRIPTION

[0025] The utility model is further described below in conjunction with the accompanying drawings.

[0026] like Figure 1 As shown, a condensate recycling system for hydrogen production by water electrolysis provided by the utility model includes a hydrogen separator 1, a hydrogen drainage tank 3, an oxygen separator 5, an oxygen drainage tank 7, a water collection tank 9, an alkali liquid collection tank 10, a self-priming pump 11, a desalted water buffer tank 13, and an alkali liquid tank 14. The hydrogen separator 1, the hydrogen drainage tank 3, and the water collection tank 9 are connected in sequence by pipelines, and the hydrogen drainage tank 3 collects condensate from other discharge points at the same time. The oxygen separator 5, the oxygen drainage tank 7, and the desalted water buffer tank 13 are connected in sequence by pipelines. A self-priming pump 11 is arranged on the upper part of the water collection tank 9 and the alkali liquid collection tank 10. The self-priming pump 11 is operated intermittently. On the one hand, when the liquid level in the water collecting tank 9 is high, the self-priming pump 11 is started to discharge water into the desalted water buffer tank 13. The alkali liquid tank 14 stores a certain amount of alkali liquid, and the water in the desalted water buffer tank 13 and the alkali liquid in the alkali liquid tank 14 are mixed and enter the electrolysis module; on the other hand, when the device is shut down, the waste alkali liquid from the discharge point such as the electrolytic cell is discharged into the alkali liquid collecting tank 10, and then enters the alkali liquid tank 14 through the self-priming pump 11.

[0027] A local level gauge and a remote level gauge are provided on the hydrogen liquid separator tank 1, and the remote level gauge is provided with high and low limit alarm functions; a switch valve a is provided on the pipeline between the hydrogen liquid separator tank 1 and the hydrogen drainage tank 3 to control the liquid level in the hydrogen liquid separator tank 1.

[0028] A local liquid level gauge and a remote liquid level gauge are arranged on the hydrogen drainage tank 3 , and the remote liquid level gauge is provided with high and low limit alarm functions; a liquid level control valve c is arranged on the pipeline between the hydrogen drainage tank 3 and the water collection tank 9 to control the liquid level in the hydrogen drainage tank 3 .

[0029] The water collection tank 9 is provided with an on-site pressure gauge and a remote pressure gauge as well as high and low limit alarm functions, and a remote liquid level meter and high and low limit alarm functions. At the same time, when the liquid level is high, the self-priming pump 11 is started by an interlock, and when the liquid level is low, the self-priming pump 11 is shut down by an interlock.

[0030] An interlocking shut-off valve b is provided between the hydrogen drainage tank 3 and the liquid level control valve c of the hydrogen drainage tank 3 when the liquid level of the hydrogen drainage tank 3 is low. When the liquid level in the hydrogen drainage tank 3 is lower than the interlocking set value (such as 20%), the interlocking shut-off valve b is automatically closed, thereby effectively preventing the risk of hydrogen entering the downstream system due to failure of the remote level gauge or the control valve c.

[0031] A local pressure gauge and a remote pressure gauge as well as high and low alarm functions are arranged on the top of the hydrogen drainage tank 3; at the same time, a nitrogen sealing system is arranged. When the pressure of the hydrogen drainage tank 3 is lower than the set value (such as 0.1MPag), low-pressure nitrogen is added through the control valve g. When the pressure of the hydrogen drainage tank 3 is higher than the set value (such as 0.1MPag), it is discharged to the venting system through the control valve h; at the same time, a safety relief facility (such as a safety valve) is arranged on the top of the hydrogen drainage tank 3 to play an overpressure protection role.

[0032] A flame arrester 12 is provided at the end of the gas phase outlet venting system pipeline of the water collecting tank 9, and the flame arrester 12 is arranged at a high point. In order to prevent air from being introduced into the system through the venting pipeline, a nitrogen purge replacement pipeline is provided at the top of the water collecting tank 9, and a flow limiting orifice plate or a control valve is provided to maintain a certain amount of nitrogen inflow.

[0033] A local level gauge and a remote level gauge are provided on the oxygen liquid separator 5 , and the remote level gauge is provided with high and low limit alarm functions; a switch valve d is provided on the pipeline between the oxygen liquid separator 5 and the oxygen drainage tank 7 to control the liquid level in the oxygen liquid separator 5 .

[0034] A local level gauge and a remote level gauge are provided on the oxygen drainage tank 7 , and the remote level gauge is provided with high and low limit alarm functions; a level control valve f is provided on the pipeline between the oxygen drainage tank 7 and the desalted water buffer tank 13 to control the liquid level in the oxygen drainage tank 7 .

[0035] The alkali solution collecting tank 10 is provided with an on-site pressure gauge and a remote pressure gauge as well as high and low limit alarm functions, and a remote liquid level meter as well as high and low limit alarm functions.

[0036] An interlocking shut-off valve e is provided between the oxygen drain tank 7 and the liquid level control valve f of the oxygen drain tank 7 when the liquid level of the oxygen drain tank 7 is low. When the liquid level in the oxygen drain tank 7 is lower than the interlocking set value (such as 20%), the interlocking shut-off valve e is automatically closed, thereby effectively preventing the risk of oxygen entering the downstream system due to failure of the remote level gauge or the control valve f.

[0037] In this embodiment, a water electrolysis hydrogen production device is taken as an example, and the device adopts a water electrolysis hydrogen production condensate recovery and utilization system. Hydrogen enters the hydrogen liquid separator tank 1 from the hydrogen side gas-liquid separation unit, and after gas-liquid separation and liquid separation, the hydrogen enters the downstream hydrogen purification unit. When the liquid level in the hydrogen liquid separator tank 1 reaches a high liquid level range of more than 70%, the liquid level control switch valve a2 opens, and the liquid enters the hydrogen drainage tank 3, and the condensate discharged from other discharge points also enters the hydrogen drainage tank 3; when the liquid level in the hydrogen liquid separator tank 1 drops to a low liquid level range of less than 20%, the liquid level control switch valve a2 is closed. The liquid in the hydrogen drainage tank 3 is controlled by the liquid level control valve c15 at the outlet of the hydrogen drainage tank 3. When the liquid level is higher than 50% of the normal liquid level, the liquid level control valve c15 is gradually opened, and the condensate enters the water collection tank 9; when the liquid level is lower than 50% of the normal liquid level, the liquid level control valve c15 is gradually closed; when the liquid level is lower than 20% of the low liquid level, the interlock cut-off valve b4 at the outlet of the hydrogen drainage tank 3 is automatically interlocked and closed. When the liquid level in the water collection tank 9 reaches a high liquid level of 70%, the self-priming pump 11 automatically starts and discharges the condensate in the tank to the deionized water buffer tank 13; when the liquid level in the water collection tank 9 drops to a low liquid level of 20%, the self-priming pump 11 automatically shuts down. The gas phase outlet of the water collection tank 9 is connected to the flame arrester 12, and the flame arrester 12 is arranged at a high point outside the plant. Oxygen enters the oxygen separator tank 5 from the oxygen side gas-liquid separation unit. After gas-liquid separation, the oxygen enters the oxygen purification unit or is discharged to the air. When the liquid level in the oxygen separator tank 5 reaches a high liquid level range of more than 70%, the liquid level control switch valve d6 opens, and the liquid enters the oxygen drainage tank 7; when the liquid level in the oxygen separator tank 5 drops to a low liquid level range of less than 20%, the liquid level control switch valve d6 is closed. The liquid in the oxygen drainage tank 7 is controlled by the liquid level control valve f16 at the outlet of the oxygen drainage tank 7. When the liquid level is higher than 50% of the normal liquid level, the liquid level control valve f16 gradually opens, and the condensate enters the desalted water buffer tank 13; when the liquid level is lower than 50% of the normal liquid level, the liquid level control valve f16 gradually closes; when the liquid level is lower than 20% of the low liquid level, the interlock cut-off valve e8 at the outlet of the oxygen drainage tank 7 is automatically interlocked and closed. The water in the desalted water buffer tank 13 and the alkali solution in the alkali solution tank 14 can directly enter the electrolysis module after proportioning. When the device is shut down, the waste alkali liquid discharged from each discharge point enters the alkali liquid collection tank 10, and then circulates back to the alkali liquid tank 14 through the self-priming pump 11.

[0038] The above is only a typical example of the utility model, and does not impose any formal limitation on the utility model. Any technician familiar with the profession, without departing from the scope of the technical solution of the utility model, shall be regarded as an equivalent example of equivalent changes made by using the above technical content. Any equivalent changes made to the above examples based on the technical essence of the utility model without departing from the content of the technical solution of the utility model shall fall within the scope of the technical solution of the utility model.

Claims

1. A condensate recycling system for producing hydrogen by water electrolysis, characterized in that: The system comprises a hydrogen separator, a hydrogen drainage tank, an oxygen separator, an oxygen drainage tank, a water collection tank, an alkali liquid collection tank, a self-priming pump, a desalted water buffer tank, an alkali liquid tank and the like; the hydrogen separator, the hydrogen drainage tank and the water collection tank are connected in sequence through pipelines, and the hydrogen drainage tank also collects waste water discharged from other discharge points; the oxygen separator, the oxygen drainage tank and the desalted water buffer tank are connected in sequence through pipelines; a self-priming pump is arranged on the upper part of the water collection tank and the alkali liquid collection tank, and when the liquid level in the water collection tank is higher than a certain liquid level, the self-priming pump is automatically started to discharge the recovered water into the desalted water buffer tank; when the liquid level in the water collection tank is lower than a certain liquid level, the self-priming pump is automatically closed; when the device is shut down, the waste alkali liquid from the discharge point such as the electrolytic cell can also be circulated back to the alkali liquid tank through the alkali liquid collection tank through the self-priming pump, and the water in the desalted water buffer tank and the alkali liquid in the alkali liquid tank are mixed and enter the electrolysis module.

2. The condensate recycling system for producing hydrogen by water electrolysis according to claim 1, characterized in that: The liquid level in the water collecting tank is higher than a certain level when the liquid level reaches a level higher than 70%; the liquid level in the water collecting tank is lower than a certain level when the liquid level drops to a level lower than 20%.

3. The condensate recycling system for producing hydrogen by water electrolysis according to claim 1, characterized in that: A local liquid level meter and a remote liquid level meter are arranged on the hydrogen liquid separation tank, and the remote liquid level meter is provided with a high and low limit alarm function; a local liquid level meter and a remote liquid level meter are arranged on the hydrogen drainage tank, and the remote liquid level meter is provided with a high and low limit alarm function; a local pressure gauge and a remote pressure gauge as well as high and low limit alarm functions are arranged on the water collection tank, and a remote liquid level meter and a high and low limit alarm function are arranged.

4. The condensate recycling system for producing hydrogen by water electrolysis according to claim 1, characterized in that: A switch valve is arranged on the pipeline between the hydrogen liquid separator tank and the hydrogen drainage tank to control the liquid level in the hydrogen liquid separator tank; a liquid level control valve is arranged on the pipeline between the hydrogen drainage tank and the water collection tank to control the liquid level in the hydrogen drainage tank.

5. The condensate recycling system for producing hydrogen by water electrolysis according to claim 1, characterized in that: An interlocking shut-off valve is arranged between the hydrogen drain tank and the hydrogen drain tank outlet liquid level control valve when the liquid level of the hydrogen drain tank is low, which can effectively prevent the risk of hydrogen entering the downstream system due to failure of the remote liquid level meter or the control valve.

6. The condensate recycling system for producing hydrogen by water electrolysis according to claim 1, characterized in that: A local pressure gauge and a remote pressure gauge as well as high and low limit alarm functions are arranged on the top of the hydrogen drainage tank; at the same time, a nitrogen sealing system is arranged. When the pressure of the hydrogen drainage tank is low, low-pressure nitrogen is added through a control valve, and when the pressure of the hydrogen drainage tank is high, it is discharged to the venting system through a control valve; at the same time, a safety relief facility is arranged on the top of the hydrogen drainage tank to play an overpressure protection role.

7. The condensate recycling system for producing hydrogen by water electrolysis according to claim 1, characterized in that: A flame arrester is arranged at the end of the pipeline of the venting system at the gas phase outlet of the water collecting tank to prevent backfire after hydrogen combustion. In order to prevent air from being introduced into the system through the venting pipeline, a nitrogen purge replacement pipeline is arranged on the top of the water collecting tank, and a certain amount of nitrogen inflow is maintained by setting a flow limiting orifice plate or a control valve.

8. The condensate recycling system for producing hydrogen by water electrolysis according to claim 1, characterized in that: The oxygen liquid separation tank is provided with a local liquid level meter and a remote liquid level meter, and the remote liquid level meter is provided with a high and low limit alarm function; the oxygen drainage tank is provided with a local liquid level meter and a remote liquid level meter, and the remote liquid level meter is provided with a high and low limit alarm function; the alkali solution collection tank is provided with a local pressure gauge and a remote pressure gauge as well as high and low limit alarm functions, and a remote liquid level gauge and high and low limit alarm functions are provided.

9. The condensate recycling system for producing hydrogen by water electrolysis according to claim 1, characterized in that: A switch valve is arranged on the pipeline between the oxygen separator tank and the oxygen drainage tank to control the liquid level in the oxygen separator tank; a liquid level control valve is arranged on the pipeline between the oxygen drainage tank and the desalted water buffer tank to control the liquid level in the oxygen drainage tank.

10. The condensate recycling system for producing hydrogen by water electrolysis according to claim 1, characterized in that: An interlocking cut-off valve is arranged between the oxygen drainage tank and the oxygen drainage tank outlet liquid level control valve when the liquid level of the oxygen drainage tank is low, which can effectively prevent the risk of oxygen entering the downstream system due to failure of the remote liquid level meter or the control valve.

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