AEM water electrolysis hydrogen production system with main and standby alkali liquor pumps

Abstract

The utility model discloses an AEM water electrolysis hydrogen production system with main and standby alkali liquor pumps, which belongs to the field of water electrolysis hydrogen production electrical control and comprises a control system, an alkali liquor box, an alkali liquor pump unit, a flow meter, an electrolytic bath, a first separation area and a second separation area, one side of the alkali liquor box is connected with the alkali liquor pump unit, the first separation area and the second separation area, and the other side of the alkali liquor box is connected with the main and standby alkali liquor pumps. The side, away from the alkali liquor box, of the alkali liquor pump unit is connected with the flow meter, and the side, away from the alkali liquor pump unit, of the flow meter is connected with the electrolytic bath. According to the AEM water electrolysis hydrogen production system with the main alkali liquor pump and the standby alkali liquor pump, the main pump and the standby pump are switched in turn at regular time, so that the service time of the two pumps can be balanced, and the service life of the two pumps is prolonged; in the switching process of the main pump and the standby pump, the frequency of the cut-in standby pump is increased, the frequency of the cut-out main pump is reduced, and non-disturbance switching is achieved, so that disturbance of flow pressure of alkali liquor in a pipeline is reduced, and impact of the alkali liquor on a valve and a membrane electrode is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of hydrogen production by electrolyzing water with electricity control, in particular to an AEM hydrogen production system by electrolyzing water with a main and standby lye pump. Background Art

[0002] Hydrogen is a clean energy source, and hydrogen production by electrolyzing water is an efficient and clean hydrogen production technology. At present, the control systems of current AEM hydrogen production equipment by electrolyzing water all adopt PLC to control the automatic operation of the whole equipment. During long-term operation, the lye pump may deteriorate or even fail due to reasons such as dampness, lye leakage and corrosion, thus affecting the hydrogen production performance of the system and even causing production interruption due to the failure of the lye pump.

[0003] Therefore, for some high-power AEM electrolytic hydrogen production equipment or key application occasions, it is particularly important to equip the system with a main and standby lye pump during design. The two lye pumps are used alternately at regular intervals, which can avoid the long-term operation of a single lye pump, thus prolonging its service life. At the same time, when the main operation pump fails or needs maintenance, the standby operation pump can be put into operation without stopping the machine online.

[0004] At the same time, for high-power AEM electrolytic hydrogen production equipment, if the main and standby lye pumps are directly switched, it will cause large disturbances in lye flow and pressure, impact on valves and membrane electrodes, and affect their service life. Content of the Utility Model

[0005] The purpose of the utility model is to provide an AEM hydrogen production system by electrolyzing water with a main and standby lye pump to solve the problems mentioned in the above background art.

[0006] To achieve the above purpose, the utility model provides an AEM hydrogen production system by electrolyzing water with a main and standby lye pump, including a control system, a lye tank, a lye pump unit, a flow meter, an electrolytic cell, a first separation area and a second separation area. One side of the lye tank is connected to the lye pump unit, the first separation area and the second separation area. The side of the lye pump unit far away from the lye tank is connected to the flow meter, and the side of the flow meter far away from the lye pump unit is connected to the electrolytic cell.

[0007] Preferably, the lye pump unit includes a first lye pump and a second lye pump (by default, the first lye pump is the main operation pump and the second lye pump is the standby operation pump).

[0008] Preferably, the first separation area includes an oxygen-liquid separation tank and a first washing tank; the second separation area includes a hydrogen-liquid separation tank and a second washing tank.

[0009] Preferably, the control system adopts a programmable logic controller.

[0010] Preferably, the first lye pump and the second lye pump are of the same model and are both frequency conversion controlled.

[0011] Preferably, the electrolytic cell is respectively connected to the oxygen-liquid separation tank and the hydrogen-liquid separation tank.

[0012] Preferably, the first lye pump and the second lye pump are in parallel.

[0013] Therefore, the AEM water electrolysis hydrogen production system with main and standby lye pumps adopting the above structure has the following beneficial effects:

[0014] (1) The application of the main and standby lye pumps solves the problem of production interruption caused by pump failure in a single lye pump system. The main and standby pumps are switched regularly in turn, which can balance the service time of the two pumps and extend their service life. At the same time, when the main pump fails or needs maintenance, the standby pump can be put into operation without stopping the machine.

[0015] (2) During the process of alternating the main and standby pumps, the control system switches the two pumps simultaneously, increases the frequency of the standby pump being switched in, and decreases the frequency of the main pump being switched out, so as to reduce the disturbance of the lye flow pressure in the pipeline and reduce its impact on the valves and membrane electrodes.

[0016] The technical solution of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0017] Figure 1 is a schematic diagram of the overall structure of an embodiment of the present invention;

[0018] Figure 2 is a control logic flow chart of the disturbance-free switching of the main and standby lye pumps in an embodiment of the present invention;

[0019] Figure 3 is a linear relationship diagram of the frequency changing with time during the disturbance-free switching of the main and standby pumps in an embodiment of the present invention;

[0020] Reference Signs

[0021] 1, lye tank; 2, first lye pump; 3, second lye pump; 4, flow meter; 5, electrolytic cell; 6, oxygen-liquid separation tank; 7, first washing tank; 8, hydrogen-liquid separation tank; 9, second washing tank. Detailed Embodiments

[0022] The technical solution of the present invention will be further described below through the drawings and embodiments.

[0023] Unless otherwise defined, the technical terms or scientific terms used in this utility model shall have the ordinary meanings understood by those with ordinary skills in the field to which this utility model belongs. The "first", "second" and similar words used in this utility model do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0024] Embodiment

[0025] As Figure 1 shown, an AEM water electrolysis hydrogen production system with a main and standby lye pump adopting the above structure includes a control system, a lye tank 1, a lye pump unit, a flow meter 4, an electrolytic cell 5, a first separation zone and a second separation zone. One side of the lye tank 1 is connected to the lye pump unit, the first separation zone and the second separation zone. The side of the lye pump unit far from the lye tank 1 is connected to the flow meter 4, and the side of the flow meter 4 far from the lye pump unit is connected to the electrolytic cell 5. The control system uses a programmable logic controller.

[0026] The lye pump unit includes a first lye pump 2 and a second lye pump 3. The first lye pump 2 and the second lye pump 3 are of the same model and are both frequency conversion controlled. The first lye pump 2 and the second lye pump 3 are in parallel.

[0027] The first separation zone includes an oxygen-liquid separation tank 6 and a first washing tank 7; the second separation zone includes a hydrogen-liquid separation tank 8 and a second washing tank 9. The electrolytic cell 5 is respectively connected to the oxygen-liquid separation tank 6 and the hydrogen-liquid separation tank 8.

[0028] Equip the AEM electrolytic hydrogen production equipment with two lye pumps, and at the same time equip the motors of each lye pump with the same frequency converter. When the system is running normally, the main and standby pumps are switched regularly in turn to balance the usage time of the lye pumps and extend their service life. At the same time, when the main operating pump fails or needs maintenance, the standby operating pump can be put into operation without stopping the machine online. The control system switches the two pumps at the same time. According to the frequency-time function, the frequency of the switched-in standby operating pump is increased, and the frequency of the switched-out main operating pump is decreased to achieve seamless switching.

[0029] As Figure 2 , the logical process of switching between the main and standby lye pumps is introduced in detail:

[0030] Step 1: Before starting, the control system designates the main pump and the standby pump (the first alkali solution pump is the main pump by default) and sets the target frequency.

[0031] Step 2: After the system is started, the main pump gradually increases the frequency according to the frequency-time function f=kt until the target frequency is reached.

[0032] Step 3: After the frequency of the main pump is increased, the control system executes the timing wheel-cut process and monitors the operating status of the main pump at the same time. If the main pump fails or has an abnormal condition during the wheel-cut timing process, the control system jumps out of the timing wheel-cut process and directly executes the fault-cut process. Perform disturbance-free switching of the main and standby pumps according to the control method described in step 4. If the main pump does not fail during the wheel-cut timing process, after the timing wheel-cut timing is reached, perform disturbance-free switching of the main and standby pumps according to the control method described in step 4.

[0033] Step 4: Further explain the method of disturbance-free switching between the main and standby pumps. The main pump and the standby pump use the same model and are both frequency-controlled. The control system switches the two pumps at the same time, increases the frequency of the standby pump that is cut in, and reduces the frequency of the main pump that is removed. The formula for the motor speed of the pump is: n = 60f / p; where n is the speed, 60 is the coefficient, f is the power frequency, and P is the number of motor poles. When the control system performs frequency conversion control, the motor frequency is within 50HZ, and the relationship between the operating speed and frequency is linear, and the speed and flow and pressure are also linear. Therefore, the flow and pressure disturbances in the pipeline during the switching process of the two pumps are small, and the impact on the system is very small.

[0034] Combination Figure 3 As shown, the frequency of the main pump at the current moment is assigned to the standby pump as the target frequency F1 for the standby pump to increase its frequency. f2=-kt (dashed line) is a frequency reduction function. The main pump is cut off with frequency reduction over time according to the f2=-kt function until the main pump stops when the f2 frequency is reduced to 0. f=kt (solid line) is a frequency increase function. The standby pump is synchronously cut into frequency increase over time according to the f1=kt (solid line) function until the frequency f1=F1, where f1 is the real-time frequency of the standby pump motor when switching to start, f2 is the real-time frequency of the main pump motor when switching off, k is a coefficient, t is a unit time, and when it changes with unit time, the real-time frequency changes linearly with time.

[0035] Since the speed and frequency are in a linear relationship, the pump flow and frequency are also in a linear relationship. During the switching process between the two pumps, the total flow and pressure of the pipeline are maintained at a constant value, which makes the pressure and flow disturbances in the switching process of the two pumps smaller, achieving disturbance-free switching.

[0036] Step 5: When the standby pump to be transported operates normally and the main transport pump stops, the control system will run the standby pump as the new main transport pump, and the original main transport pump as the standby pump. If the fault of the stopped faulty pump has not been eliminated, the system will keep running at the current frequency and will not enter the timing wheel-cutting process. It is not until the fault of the faulty pump disappears that the system will enter the timing wheel-cutting process again and cycle in this way.

[0037] Compared with the single-pump system, the main pump and the standby pump are switched periodically in turn, which prolongs the service life of the balanced caustic soda pump by extending its usage time. At the same time, when the main transport pump fails or needs maintenance, the standby pump can be put into operation without stopping the machine online. During the process of switching between the main pump and the standby pump, seamless switching is achieved by controlling the operating frequencies of the main pump and the standby pump, reducing the disturbance of their flow rate and pressure and minimizing the impact on the valves and the membrane electrodes in the electrolytic cell.

[0038] Therefore, the AEM water electrolysis hydrogen production system with a main and standby caustic soda pump adopting the above structure realizes seamless switching by controlling the operating frequencies of the main pump and the standby pump, reduces the disturbance of their flow rate and pressure, and minimizes the impact on the valves and the membrane electrodes in the electrolytic cell.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An AEM water electrolysis hydrogen production system with main and standby lye pumps, characterized in that: It includes a control system, an alkali solution tank, an alkali solution pump unit, a flow meter, an electrolytic cell, a first separation zone and a second separation zone. One side of the alkali solution tank is connected to the alkali solution pump unit, the first separation zone and the second separation zone. The side of the alkali solution pump unit away from the alkali solution tank is connected to the flow meter. The side of the flow meter away from the alkali solution pump unit is connected to the electrolytic cell.

2. The AEM water electrolysis hydrogen production system with a main and standby lye pump according to claim 1, characterized in that: The alkali solution pump unit includes a first alkali solution pump and a second alkali solution pump.

3. The AEM water electrolysis hydrogen production system with a main and standby lye pump according to claim 1, wherein: The first separation zone includes an oxygen-liquid separation tank and a first washing tank; the second separation zone includes a hydrogen-liquid separation tank and a second washing tank.

4. The AEM water electrolysis hydrogen production system with a main and standby lye pump according to claim 1, characterized in that: The control system uses a programmable logic controller.

5. The AEM water electrolysis hydrogen production system with a main and standby lye pump according to claim 2, characterized in that: The first alkali solution pump and the second alkali solution pump are of the same model and are both frequency conversion controlled.

6. The AEM water electrolysis hydrogen production system with a main and standby lye pump according to claim 3, wherein: The electrolytic cell is respectively connected to the oxygen-liquid separation tank and the hydrogen-liquid separation tank.

7. An AEM water electrolysis hydrogen production system with a main and standby lye pump according to claim 5, characterized in that: The first alkali solution pump and the second alkali solution pump are in parallel.

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