CN115323389A - Circulating ion quantity control system and method for hydrogen production water of PEM (proton exchange membrane) electrolytic cell - Google Patents

Abstract

The invention provides a circulating ion quantity control system and method for hydrogen production water of a PEM electrolytic cell, wherein the system comprises the following components: the system comprises a circulating water storage container, a switch unit, a deionization unit, a water mixing control unit, a first conductivity feedback unit, a first flow feedback unit, an electrolytic cell unit, a second conductivity feedback unit, a second flow feedback unit and a circulating unit; wherein: a circulating unit, a second flow feedback unit and a second conductivity feedback unit are arranged on a first main circulating path flowing from the circulating water storage container to the electrolytic cell unit; and a switch unit, a deionization unit, a mixed water control unit, a first conductivity feedback unit and a first flow feedback unit are arranged on a second circulation main path flowing from the electrolytic cell unit to the circulation water storage container. The invention controls ions in the process of electrolyzing water by comparing the conductivities fed back by the two conductivity feedback units.

Description

A PEM electrolyzer hydrogen production water circulation ion quantity control system and method

technical field

The present application relates to the technical field of hydrogen production by electrolysis of water, in particular to a system and method for controlling the amount of circulating ions in water produced by a PEM electrolyzer for hydrogen production.

Background technique

Driven by global warming, hydrogen energy, as a high calorific value, zero-pollution energy source, has been greatly developed. As a secondary energy source like electricity, hydrogen energy is an energy source obtained through artificial processing.

As the cost of photovoltaic, wind power, and sea power decreases, green hydrogen, that is, electrolysis of water to produce hydrogen, becomes possible. Hydrogen production by water electrolysis means that water molecules are dissociated under the action of direct current to generate oxygen and hydrogen, which are separated from the anode and cathode of the electrolytic cell, respectively. According to the different materials of electrolyzer diaphragm, water electrolysis hydrogen production is usually divided into alkaline water electrolysis (AE), proton exchange membrane (PEM) water electrolysis and high temperature solid oxide water electrolysis (SOEC).

Hydrogen production by PEM electrolyzer is the process of electrolyzing pure water with direct current to produce hydrogen and oxygen. The cathode is the hydrogen-producing end, and the anode is the oxygen-producing end. The entire electrolysis process needs to continuously and stably apply pure water that meets the conductivity requirements to the cathode side. During the reaction process, the pure water is continuously consumed, and the ion concentration is continuously increased. The components of the circulating waterway have ion precipitation under the high-temperature hydrogenation cycle, which makes the conductivity of the electrolyzer circulating waterway increase rapidly. The control of ions in the process of electrolyzing water in the electrolyzer is particularly important.

The existing technology generally replaces the water quality through external circulation, or reduces the conductivity through online multi-stage filtration, RO reverse osmosis membrane and combined equipment. Since hydrogen energy is an emerging industry, there is no special standardized equipment, and the original equipment is basically Used for sewage treatment, tap water hardness reduction, etc. This kind of equipment is bulky, consumes a lot of water, and is not resistant to high temperature. When the water is produced for the first time, the conductivity is reduced a little bit, that is, the conductivity of the initial water part is relatively high. , the final conductivity is an indicator of mixing. It is not suitable for the electrolytic tank, which requires high conductivity. On the other hand, this kind of water production technology cannot be carried out in an environment of 70-80 degrees, and the high temperature will cause great damage to the membrane. Frequent water replacement is also not suitable. On the one hand, the loss of power consumption is too large, and on the other hand, it has a great impact on the reaction environment of the electrolyzer.

Contents of the invention

In view of this, the present invention provides a PEM electrolyzer hydrogen production water circulation ion control system and method, by comparing the conductivity fed back by two conductivity feedback units to control the ions in the process of electrolyzing water.

For this reason, the present invention adopts following technical scheme:

The invention provides a PEM electrolyzer hydrogen production water circulation ion quantity control system, the system includes: a circulation water storage container, a switch unit, a deionization unit, a mixed water control unit, a first conductivity feedback unit, and a first flow feedback unit. unit, an electrolytic cell unit, a second conductivity feedback unit, a second flow feedback unit and a circulation unit; wherein:

A circulation unit, a second flow feedback unit and a second conductivity feedback unit are arranged on the first circulation main road flowing from the circulation water storage container to the electrolytic cell unit;

A switch unit, a deionization unit, a mixed water control unit, a first conductivity feedback unit and a first flow feedback unit are arranged on the second circulation main road flowing from the electrolytic cell unit to the circulation water storage container;

The control system performs ion control in the process of electrolyzing water by comparing the conductivity fed back by two conductivity feedback units.

Further, the deionization unit includes multiple deionization units connected in parallel.

Further, it also includes: a water replenishment container; the pure water in the water replenishment container is replenished into the circulating water storage container through the water replenishment circulation unit as required.

Further, it also includes: an opening control unit arranged between the circulating water storage container and the drain outlet, and when drainage is required, the water in the circulating water storage container is discharged from the drain outlet through the opening control unit.

Further, it also includes: a pressure control unit arranged between the circulating water storage container and the exhaust port, when the pressure in the circulating water storage container reaches the pressure set by the pressure control unit, the pressure control unit sends the gas from the exhaust port discharge.

Further, it also includes: a safety control unit arranged between the circulating water storage container and the exhaust port. When the pressure control of the pressure control unit fails or is abnormal, the safety control unit automatically discharges the gas from the exhaust port.

The present invention also provides a method for controlling the amount of circulating ions in the hydrogen-producing water of the PEM electrolyzer. Based on the above-mentioned control system for the circulating ion amount of the hydrogen-producing water in the PEM electrolyzer, the method includes:

Obtaining the conductivity fed back by the first conductivity feedback unit and the second conductivity feedback unit in real time;

When the conductivity fed back by the first conductivity feedback unit exceeds the first preset value and the conductivity fed back by the second conductivity feedback unit does not exceed the second preset value, the mixed water control unit opens the deionization unit path and turns on the switch unit , performing conductivity removal; until the conductivity difference fed back by the first conductivity feedback unit and the second conductivity feedback unit is stable; the second preset value is smaller than the first preset value.

Further, the method further includes: when the deionization unit needs to be replaced, controlling the switch unit to be turned off.

Further, when the conductivity value of the second conductivity feedback unit exceeds the third preset value, the opening control unit is opened to control drainage, and at the same time, according to the liquid level display in the circulating water storage container, it is judged whether the circulating water storage container needs Perform water replenishment, and stop changing the water when the conductivity value fed back by the second conductivity feedback unit returns to a specified value; the third preset value is higher than the second preset value.

Further, when the conductivity fed back by the second conductivity feedback unit does not exceed the second preset value, and the conductivity fed back by the first conductivity feedback unit exceeds the fourth preset value, it indicates that the electrolytic cell unit is abnormal, and the alarm prompts manual Processing: the fourth preset value is higher than the third preset value.

Advantage and positive effect of the present invention:

The present invention realizes the on-line processing of the conductivity. For the electrolytic cell, which directly affects the performance of the conductivity parameter, it should better remove the concentrated ions in the reactant or the ions precipitated by the electrolytic cell. Hydrogen properties have a positive impact. The core of the control in the present invention is dual conductivity detection, and automatic control is performed according to the index state. This online, high temperature resistant, and non-stop solution is beneficial to the continuous operation of the equipment. The hydrogen production process of the electrolyzer is a high-pressure environment. In addition to the performance index requirements for continuous operation of the equipment, it is necessary to reduce the possibility of personnel operating the equipment in a high-pressure environment. The on-line deionization unit marked in the present invention is not limited to one. In practical application, multiple units can be connected in parallel and equipped with a safety control unit, which can not only ensure 24-hour unattended safe operation, but also has great advantages in terms of safety.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is a schematic structural view of a system for controlling the amount of circulating ions in hydrogen-producing water in a PEM electrolyzer in an embodiment of the present invention.

Detailed ways

In order to enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

The present invention provides a circulating water deionization control system and method for pure water hydrogen production by PEM electrolyzer, which can be applied to PEM electrolyzer pure water hydrogen production equipment, PEM electrolyzer hydrogen production test platform, and PEM electrolyzed water hydrogen production demonstration items etc.

The key point of the present invention is the self-made deionizer with high pressure resistance, which can be used in the main circulation circuit, and the flow rate can reach hundreds of liters per minute. This system can partially and continuously replace the water quality according to the real-time detection of the online conductivity during the high-pressure production process without affecting the operation. By comparing the values of two conductivity detectors, the internal state of the electrolytic cell is monitored.

As shown in Figure 1, the PEM electrolyzer hydrogen production water circulation ion quantity control system provided in the embodiment of the present invention mainly includes: water replenishment container 1, water replenishment circulation unit 2, circulation water storage container 3, opening degree control unit 4, switch unit 5. Deionization unit 6, mixed water control unit 7, first conductivity feedback unit 8, first flow feedback unit 9, electrolytic cell unit 10, second conductivity feedback unit 11, second flow feedback unit 12, circulation unit 13. Pressure control unit 14 and safety control unit 15; the control system performs ion control in the process of electrolyzing water by comparing the conductivity fed back by the two conductivity feedback units. in:

The pure water in the replenishing water container 1 is replenished into the circulating water storage container 3 through the replenishing water circulation unit 2 as required, and the water quality can be changed without stopping the machine. The opening control unit 4 is arranged between the circulating water storage container 3 and the drain outlet, and when drainage is required, the water in the circulating water storage container 3 can be discharged from the drain outlet through the opening control unit 4 .

Pure water circulates between the circulating water storage container 3 and the electrolytic cell unit 10, and a circulation unit 13, a second flow feedback unit 12 and a second flow feedback unit 12 are arranged on the first circulation main road flowing from the circulating water storage container 3 to the electrolytic cell unit 10. Two conductivity feedback unit 11. Wherein, the circulation unit 13 is used to promote the flow of pure water from the circulating water storage container 3 to the electrolytic cell unit 10; the second flow feedback unit 12 is used to measure in real time the flow of pure water flowing out from the circulating water storage container 3; the second conductance The rate feedback unit 11 is used to measure the conductivity of the pure water flowing into the electrolytic cell unit 10 in real time.

After the pure water undergoes the electrolysis reaction of the electrolytic cell unit 10 , the generated gas and mixed water flow to the circulating water storage container 3 . A switch unit 5 , a deionization unit 6 , a mixed water control unit 7 , a first conductivity feedback unit 8 and a first flow feedback unit 9 are arranged on the second circulation main road flowing from the electrolytic cell unit 10 to the circulation water storage container. Wherein, the first flow feedback unit 9 is used for real-time measurement of the mixed water flow generated from the electrolytic cell unit; the first conductivity feedback unit 8 is used for real-time measurement of the mixed water conductivity flowing out of the electrolytic cell unit 10; by comparing the two conductivity The conductivity fed back by the feedback unit, that is, comparing the conductivity of water flowing into and out of the electrolytic cell unit 10, comparing the flow rates fed back by the two flow feedback units, that is, comparing the flow of water flowing in and out of the electrolytic cell unit 10, can determine the electrolysis rate. The internal operating state of the pool unit 10. The switch unit 5 , the deionization unit 6 and the mixed water control unit 7 form a deionization branch circuit, which selectively deionizes the mixed water generated by the electrolytic cell unit 10 according to the magnitude of the conductivity. There can be one deionization unit 6 or multiple ones. Specifically, multiple deionization units are arranged in parallel. When multiple parallel deionization units 6 are set in the system, a safety control unit can also be set. The unit selects one or more deionization units for deionization, which can fully guarantee the deionization effect and the safe operation of the system.

The pressure control unit 14 and the safety control unit 15 are all arranged between the circulating water storage container 3 and the exhaust port, the pure water flows back to the circulating water storage container 3 through the deionization unit 6 and the main road, and the circulating water storage container 3 As the reaction continues, the gas will gradually increase and the pressure of the circulation path will be increased. When the pressure reaches the pressure set by the pressure control unit 14, the gas will be discharged from the pressure control unit 14, making the reaction run continuously. When the pressure control fails or abnormality occurs, the safety control unit 15 will automatically release the pressure.

Based on the PEM electrolyzer hydrogen production water circulation ion volume control system provided in the above embodiments, the embodiment of the present invention also provides a PEM electrolyzer hydrogen production water circulation ion volume control method, including:

The control system controls the flow entering the branch circuit and the main circuit according to the value fed back by the first flow feedback unit 8. When the conductivity value fed back by the first flow feedback unit 8 is relatively high, the flow rate flowing into the deionization unit 6 accounts for a large proportion. The switch unit 5 is normally open, and when the deionization unit 6 needs to be replaced, the switch unit 5 is closed.

When the conductivity of the entire loop is very low, that is, when the water is newly circulated, the switch unit 5 is in the closed state, and the mixed water control unit 7 closes the path leading to the deionization unit 6 according to the low value fed back by the first flow feedback unit 9, and the cycle is main road.

The conductivity of the whole loop is not high, that is, when the conductivity fed back by the first conductivity feedback unit 8 exceeds the first preset value (the conductivity fed back by the first conductivity feedback unit 8 exceeds the standard), the second conductivity feedback unit 11 feedbacks When the conductivity does not exceed the second preset value (the conductivity fed back by the second conductivity feedback unit 11 is not high), the mixed water control unit 7 opens the path of the deionization unit 6 and opens the switch unit 5 to remove the conductivity. Until the difference between the first conductivity feedback unit 8 and the second conductivity feedback unit 11 becomes stable.

When the conductivity of the whole loop is high, that is, the conductivity value of the second conductivity feedback unit 11 has exceeded a certain value (the conductivity value of the second conductivity feedback unit 11 exceeds the third preset value, and the third preset value is higher than the first Two preset values), the control system opens the opening control unit 4 to control drainage, and the control system judges whether the circulating water storage container 3 needs to replenish water according to the liquid level display in the circulating water storage container 3. When the conductivity value returns to the specified When the value is high, stop changing the water. If the value continues to be high, the control system controls the opening valve to increase the amount of water exchange and replace more pure water.

During the entire loop operation, when the conductivity fed back by the second conductivity feedback unit 11 does not exceed the second preset value (the conductivity fed back by the second conductivity feedback unit 11 is not high), the first conductivity feedback unit 8 feedbacks When the conductivity exceeds the fourth preset value (the conductivity fed back by the first conductivity feedback unit 8 is too high, and the fourth preset value is higher than the third preset value), it means that there is an abnormality in the electrolytic cell unit 10, and an alarm is required to prompt manual operation. deal with.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (10)

1. A PEM electrolyzer hydrogen production water circulating ion quantity control system is characterized in that, the system comprises: circulating water storage container (3), switch unit (5), deionization unit (6), mixed water control unit ( 7), the first conductivity feedback unit (8), the first flow feedback unit (9), the electrolytic cell unit (10), the second conductivity feedback unit (11), the second flow feedback unit (12) and the circulation unit (13); where: A circulation unit (13), a second flow feedback unit (12) and a second conductivity feedback unit (11) are arranged on the first circulation main road flowing from the circulation water storage container (3) to the electrolytic cell unit (10); A switch unit (5), a deionization unit (6), a mixed water control unit (7), a first conductivity feedback unit ( 8) and the first flow feedback unit (9); The control system performs ion control in the process of electrolyzing water by comparing the conductivity fed back by two conductivity feedback units. 2. A kind of PEM electrolyzer hydrogen production water circulating ion quantity control system according to claim 1, is characterized in that, also comprises: replenishing water container (1); The pure water in described replenishing water container (1) passes through replenishing water circulation unit (2) Fill the circulating water storage container (3) as needed. 3. A kind of PEM electrolyzer hydrogen production water circulating ion quantity control system according to claim 1, is characterized in that, also comprises: the opening degree control unit (4) that is arranged between circulating water storage container (3) and drain outlet ), when drainage is required, the water in the circulating water storage container (3) is discharged from the water outlet through the opening control unit (4). 4. A kind of PEM electrolyzer hydrogen production water circulating ion quantity control system according to claim 1, is characterized in that, also comprises: be arranged on the pressure control unit (14) between circulating water storage container (3) and exhaust port ), when the pressure in the circulating water storage container (3) reaches the pressure set by the pressure control unit (14), the pressure control unit (14) will discharge the gas from the exhaust port. 5. A kind of PEM electrolyzer hydrogen production water circulating ion quantity control system according to claim 4, is characterized in that, also comprises: the safety control unit (15 that is arranged between circulating water storage container (3) and exhaust port ), when the pressure control of the pressure control unit (14) fails or is abnormal, the safety control unit (15) automatically discharges the gas from the exhaust port. 6 . The system for controlling the amount of circulating ions in the hydrogen production water of a PEM electrolyzer according to claim 1 , wherein the deionization unit comprises a plurality of deionization units connected in parallel. 7 . 7. A method for controlling the amount of circulating ions in water produced by a PEM electrolyzer, characterized in that, based on the system for controlling the amount of circulating ions in water produced by a PEM electrolyzer according to any one of claims 1 to 6, the method comprises: Obtaining the conductivity fed back by the first conductivity feedback unit (8) and the second conductivity feedback unit (11) in real time; When the conductivity fed back by the first conductivity feedback unit (8) exceeds the first preset value and the conductivity fed back by the second conductivity feedback unit (11) does not exceed the second preset value, the mixed water control unit (7) Open the deionization unit (6) path, open the switch unit (5), and remove the conductivity; until the conductivity difference fed back by the first conductivity feedback unit (8) and the second conductivity feedback unit (11) is stable; the The second preset value is smaller than the first preset value. 8. A method for controlling the amount of circulating ions in PEM electrolyzer hydrogen production water circulation according to claim 7, characterized in that the method further comprises: when the deionization unit (6) needs to be replaced, the control switch unit (5) is turned off . 9. A method for controlling the amount of circulating ions in a PEM electrolyzer hydrogen production water according to claim 7, characterized in that, when the conductivity value of the second conductivity feedback unit (11) exceeds the third preset value, the switch is turned on The degree control unit (4) controls the drainage, and at the same time, according to the liquid level display in the circulating water storage container (3), it is judged whether the circulating water storage container (3) needs to replenish water. When the second conductivity feedback unit (11) feedbacks When the conductivity value returns to a specified value, stop changing the water; the third preset value is higher than the second preset value. 10. A method for controlling the amount of circulating ions in PEM electrolyzer hydrogen production water according to claim 7, characterized in that, when the conductivity fed back by the second conductivity feedback unit (11) does not exceed the second preset value, the first When the conductivity fed back by the conductivity feedback unit (8) exceeds the fourth preset value, it indicates that the electrolytic cell unit (10) is abnormal, and the alarm prompts manual processing; the fourth preset value is higher than the third preset value .

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