Electrolytic hydrogen production system and method for deeply reducing hydrogen content in oxygen

Abstract

The invention discloses an electrolytic hydrogen production system and method for deeply reducing the hydrogen content in oxygen. Comprising an alkaline electrolytic bath, an oxygen side gas-liquid separator, a hydrogen side gas-liquid separator, an alkaline liquor circulating pump, a first gas-liquid separator additionally arranged on the front side of the oxygen side gas-liquid separator, and a hydrogen-in-oxygen deep separation device for deeply removing hydrogen in an oxygen side gas-phase product, the first gas-liquid separator is additionally arranged in the oxygen-side gas-liquid separation system, so that a deep separation device capable of purifying and dehydrogenating the oxygen-side gas-phase product can be realized, and when the hydrogen content in oxygen at the gas-phase outlet of the oxygen-side gas-liquid separator is relatively high, the hydrogen-in-oxygen deep separation device is started to deeply remove hydrogen in the oxygen-side gas-liquid separation system, so that the hydrogen content in the oxygen-side gas-liquid separation system is greatly reduced. And the hydrogen content in oxygen in the water electrolysis hydrogen production system is reduced, and the safety of the system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production by electrolysis of water, and in particular to a hydrogen production system and method by electrolysis for deeply reducing the hydrogen content in oxygen. Background Art

[0002] With the continuous growth of low-carbon emission reduction demand worldwide and the background of "dual carbon", water electrolysis hydrogen production technology has received widespread attention. Using renewable energy to produce hydrogen by water electrolysis is not only the process solution to achieve the lowest carbon emissions today, but also the most promising technology in the future. Water electrolysis hydrogen production converts abundant renewable energy such as photovoltaics and wind power into clean and efficient green hydrogen energy, which is applied to chemical, transportation, metallurgy, and other fields. It not only achieves deep decarbonization, but also is an important support for the "dual carbon" goal. However, hydrogen in oxygen (HTO) is an important parameter for evaluating the safety of hydrogen production equipment. If the hydrogen content in oxygen exceeds the standard, it will bring safety hazards to the operation of the hydrogen production equipment. In severe cases, it may cause safety accidents, resulting in casualties and inestimable losses. In general, when the concentration of hydrogen in oxygen exceeds 2%, the two gases can form an explosive mixture, and the electrolysis system will be forced to shut down, and then the hydrogen production process will stop, which may even bring serious safety hazards and production impacts. Reducing the concentration of hydrogen in oxygen in the electrolysis system can not only reduce the occurrence of dangerous accidents, but also improve production efficiency.

[0003] Therefore, in order to deal with the operational safety hazards and production impacts caused by the increase in hydrogen concentration in oxygen under low load in the water electrolysis hydrogen production system, it is necessary to design a scientific and reasonable solution to reduce the hydrogen impurity content during operation. This solution not only helps to ensure the safe operation of the system and reduce production costs, but also further optimizes the electrolysis efficiency and promotes the large-scale development of the green hydrogen energy industry.

[0004] CN118186493A provides a method and device for improving the purity of hydrogen in oxygen in alkaline water electrolysis hydrogen production equipment, which ensures the purity of gas produced by the equipment and the safety of operation of the hydrogen production equipment under wide power fluctuation operation, and broadens the operable power range of the alkaline water electrolysis hydrogen production equipment. This patent determines the operable power range by giving a formula for the recommended value of circulating water flow and temperature through experiments, but the fluctuation range of fluctuating renewable energy is quite large and it is often difficult to accurately determine the calculated operable power range. Therefore, this patent cannot alleviate the problem of excessive hydrogen impurities in oxygen when the alkaline water electrolysis system is working at low load.

[0005] CN117144416A discloses a control system and method for the hydrogen content in oxygen under low-load conditions in an alkaline water electrolysis hydrogen production system. As the load of the electrolyzer decreases, the system controls the circulation volume of the electrolyzer alkali solution to increase as the load decreases. When the load of the electrolyzer drops below the low load, the regulation of the circulation volume of the alkali solution is turned on to synchronize the changes in the circulation volume of the alkali solution. The two are tracked and regulated according to the corresponding proportional relationship to ensure that the control of hydrogen in oxygen operates within the allowed safe range. When the load of the electrolyzer fluctuates up and down, the controlled circulation volume of the alkali solution tracks the changes in the load and changes accordingly. This method ensures safe operation through synchronous regulation, but complex gas purification and gas storage equipment are introduced into the system, which greatly increases the footprint of the electrolysis system and does not meet the development needs of industrial containerized links.

[0006] Therefore, in order to address the problem of excessively high hydrogen content in oxygen in industrial electrolysis systems operating at low loads, it is necessary to develop more efficient, more feasible, and integrated technical devices for reducing the concentration of hydrogen in oxygen to ensure the safe operation of the electrolysis system under low loads. This is of great significance for promoting the safe, stable and efficient development of the water electrolysis industry. Summary of the invention

[0007] The object of the present invention is to provide a system and method for producing hydrogen by electrolysis for deeply reducing the hydrogen content in oxygen, so as to solve the problem of excessively high hydrogen content in oxygen in an alkaline electrolysis hydrogen production system when the electrolyzer is operated at low load.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] The first aspect of the present invention is to provide an electrolytic hydrogen production system for deeply reducing the hydrogen content in oxygen, comprising an alkaline electrolytic cell, an oxygen-side gas-liquid separator, a hydrogen-side gas-liquid separator, and an alkaline solution circulation pump;

[0010] The alkaline electrolytic cell is provided with an oxygen side gas-liquid mixed phase outlet at the top of the anode side, and a hydrogen side gas-liquid mixed phase outlet at the top of the cathode side;

[0011] A first hydrogen sensor is provided at the gas phase outlet of the oxygen-side gas-liquid separator for monitoring the hydrogen content in oxygen in the alkaline water electrolysis hydrogen production system;

[0012] A first gas-liquid separator is installed in front of the oxygen-side gas-liquid separator, and the first gas-liquid separator is connected to the oxygen-side gas-liquid mixed phase outlet, and is used to perform preliminary gas-liquid separation on the gas-liquid mixed liquid received from the anode side of the alkaline electrolyzer; the gas phase outlet and the liquid phase outlet of the first gas-liquid separator are both connected to the oxygen-side gas-liquid separator through pipelines; the gas phase outlet of the first gas-liquid separator is connected to an oxygen-hydrogen deep separation device through a pipeline, and the oxygen-hydrogen deep separation device includes a first valve assembly, a power mechanism and a catalytic reactor, and the gas phase outlet of the catalytic reactor is connected to the oxygen-side gas-liquid separator through a pipeline; the first valve assembly and the power mechanism are used to control the operating state of the oxygen-hydrogen deep separation device, and the catalytic reactor is used to catalytically dehydrogenate the gas phase product from the gas phase outlet of the first gas-liquid separator.

[0013] Furthermore, the first gas-liquid separator is provided with a first gas-liquid mixed phase inlet on one side, a first gas phase outlet on the other side, and a first liquid phase outlet at the bottom;

[0014] The oxygen-side gas-liquid separator is provided with a second liquid phase inlet on one side, a second liquid phase outlet on the other side, and a second gas phase outlet on the top;

[0015] The hydrogen-side gas-liquid separator is provided with a third gas-liquid mixed phase inlet on one side, a third liquid phase outlet on the other side, and a third gas phase outlet on the top;

[0016] The catalytic reactor is provided with a catalytic reactor inlet line on one side and a catalytic reactor outlet line on the other side;

[0017] A mixed alkali solution inlet is provided at the bottom of the alkaline electrolytic cell, and a mixed alkali solution inlet line is provided at the mixed alkali solution inlet;

[0018] The oxygen-side gas-liquid mixed phase outlet is connected to the first gas-liquid mixed phase inlet through a first pipeline; a first gas phase outlet is provided at the first gas phase outlet, and the first gas phase outlet is connected to the catalytic reactor inlet through a pipeline; the first gas phase outlet is connected to the top of the oxygen-side gas-liquid separator through a second pipeline; the catalytic reactor outlet is connected to the oxygen-side gas-liquid separator through a third pipeline; the first liquid phase outlet is connected to the second liquid phase inlet through a fourth pipeline, the second liquid phase outlet is connected to the mixed alkali liquid inlet through a fifth pipeline, and a second gas phase outlet is provided at the second gas phase outlet;

[0019] The hydrogen side gas-liquid mixed phase outlet is connected to the third gas-liquid mixed phase inlet through the sixth pipeline, the third liquid phase outlet is connected to the mixed alkali liquid inlet line through the seventh pipeline, and the third gas phase outlet is provided with a third gas phase outlet line.

[0020] Furthermore, the power mechanism is a fan, and the fan is arranged on the inlet line of the catalytic reactor.

[0021] A fan is used as a power mechanism to provide power for the oxygen-hydrogen deep separation device. The oxygen-side gas phase product separated by the first gas-liquid separator is transported to the catalytic reactor for catalytic dehydrogenation through the fan, which is beneficial for the contact reaction between oxygen and hydrogen and the catalyst. The gas flow, pressure, temperature and other conditions in the reaction process can be adjusted through the fan, which is convenient for controlling the reaction process.

[0022] Furthermore, the first valve assembly includes a first valve, a second valve and a third valve, the first valve is arranged on the inlet line of the catalytic reactor, the second valve is arranged on the outlet line of the catalytic reactor or the third pipeline, and the third valve is arranged on the second pipeline.

[0023] When the oxygen-hydrogen deep separation device needs to be started, the first valve, the second valve and the fan are opened, and the third valve is closed to enable the oxygen-hydrogen deep separation device to start operating; when the oxygen-hydrogen deep separation device is not needed to be operated, the third valve is opened and the fan is closed.

[0024] Furthermore, a condensate outlet line is provided at the bottom of the catalytic reactor, and the condensate outlet line is connected to the oxygen-side gas-liquid separator.

[0025] A condensate outlet line is arranged at the bottom of the catalytic reactor and connected to the oxygen-side gas-liquid separator, so that the water generated in the catalytic reactor can enter the oxygen-side gas-liquid separator from the bottom of the catalytic reactor in the form of condensate. Since the main reactions in the catalytic reactor are: (Exothermic reaction), the condensed water has a high temperature and enters the oxygen side gas-liquid separator, which can increase the temperature of the alkaline electrolyte in the oxygen side gas-liquid separator, reduce the solubility of hydrogen in the alkaline electrolyte, and further reduce the hydrogen content in the oxygen in the alkaline water electrolysis hydrogen production system.

[0026] Furthermore, a demister is provided on the first gas phase outlet line, and the demister is used to remove liquid droplets in the oxygen-side gas phase product separated by the first gas-liquid separator. The designed flow rate of the demister is 3.5-5.5 m / s.

[0027] Furthermore, a second hydrogen sensor is provided on the inlet line of the catalytic reactor, and a third hydrogen sensor is provided on the outlet line of the catalytic reactor.

[0028] Hydrogen sensors are installed before and after the catalytic reactor to monitor the hydrogen content in oxygen at the inlet and outlet of the catalytic reactor, so as to determine whether the catalytic reactor is operating normally.

[0029] Furthermore, the catalytic reactor has a first cavity filled with a catalyst that promotes the reaction of hydrogen and oxygen; a first grid plate is disposed at the front end of the first cavity, and a second grid plate is disposed at the rear end.

[0030] The second aspect of the present invention is to provide a method for producing hydrogen by electrolysis for deeply reducing the hydrogen content in oxygen, using the above-mentioned device for producing hydrogen by electrolysis for deeply reducing the hydrogen content in oxygen, comprising the following steps:

[0031] S1. Under the action of direct current, the alkaline electrolyte in the alkaline electrolytic cell becomes a gas-liquid mixture of a large number of fine bubbles;

[0032] S2. Under the action of the alkali liquid circulation pump, the gas-liquid mixture on the anode side of the alkaline electrolytic cell enters the first gas-liquid separator for preliminary gas-liquid separation, and the oxygen-side gas phase product and the oxygen-side alkali liquid after the preliminary separation enter the oxygen-side gas-liquid separator for secondary gas-liquid separation; under the action of the alkali liquid circulation pump, the gas-liquid mixture on the cathode side of the alkaline electrolytic cell enters the hydrogen-side gas-liquid separator for gas-liquid separation;

[0033] S3. The oxygen-side gas phase product after secondary separation is discharged from the top of the oxygen-side gas-liquid separator and enters the next processing step; the oxygen-side alkali liquid after secondary separation re-enters the alkaline electrolytic cell under the action of the alkali liquid circulation pump to participate in electrolytic hydrogen production; the hydrogen-side gas phase product after passing through the gas-liquid separator is discharged from the top of the hydrogen-side gas-liquid separator and enters the next processing step, and the hydrogen-side alkali liquid after gas-liquid separation re-enters the alkaline electrolytic cell under the action of the alkali liquid circulation pump to participate in electrolytic hydrogen production;

[0034] S4. When the alkaline electrode cell is operating under low load or when the first hydrogen sensor detects that the content of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system exceeds 1.5%, the oxygen-hydrogen deep separation device is opened by controlling the first valve group and the power mechanism, and the oxygen-hydrogen deep separation device starts to operate, and the oxygen-side gas phase product separated by the first gas-liquid separator is deeply dehydrogenated. The oxygen-side gas phase product after the deep dehydrogenation enters the oxygen-side gas-liquid separator to participate in secondary gas-liquid separation; when the first hydrogen sensor detects that the content of hydrogen in oxygen in the alkaline water electrolysis system is lower than 1%, the oxygen-hydrogen deep separation device is closed by controlling the first valve assembly and the power mechanism to reduce energy consumption.

[0035] Furthermore, in step S4, when the oxygen-hydrogen deep separation device is in operation, the air speed of the fan is 2-10h -1 .

[0036] Control the air speed of fan 512 to 2-10h -1 The oxygen-side gas phase product separated by the first gas-liquid separator 20 is transported to the catalytic reactor 50, so that the oxygen and hydrogen in the gas phase product can contact the catalyst at a high superficial rate, thereby greatly improving the chemical reaction efficiency.

[0037] Compared with the prior art, the present invention has at least the following beneficial effects:

[0038] The present invention performs preliminary gas-liquid separation on the gas-liquid mixed liquid on the anode side of the alkaline electrolytic cell by installing a first gas-liquid separator in front of the oxygen-side gas-liquid separator, and a deep separation device for removing hydrogen from oxygen is connected to the gas phase outlet of the first gas-liquid separator; a hydrogen sensor for monitoring the hydrogen content in oxygen of the alkaline electrolysis hydrogen production system is arranged at the gas phase outlet of the oxygen-side gas-liquid separator, and when the hydrogen sensor detects that the hydrogen content in oxygen in the alkaline water electrolysis hydrogen production system is too high, the deep separation device for separating hydrogen from oxygen is turned on, so that the oxygen-side gas phase product separated by the first gas-liquid separator enters the catalytic reactor for deep dehydrogenation (catalytic dehydrogenation), deeply reduces the hydrogen content in oxygen in the oxygen-side gas phase product, and the oxygen-side gas phase product after the catalytic dehydrogenation enters the oxygen-side gas-liquid separator for secondary separation, thereby reducing the hydrogen content in oxygen in the alkaline water electrolysis hydrogen production system and improving the safety of the alkaline water electrolysis hydrogen production system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the electrolytic hydrogen production system for deeply reducing the hydrogen content in oxygen according to the present invention.

[0040] Figure 2 It is a schematic diagram of the working process of coupling the oxygen-side gas-liquid separator with the first gas-liquid separator and the oxygen-hydrogen deep separation device of the present invention.

[0041] Figure 3 It is a schematic diagram of the structure of the catalytic reactor in the oxygen-hydrogen deep separation device of the present invention.

[0042] Figure 4 It is a schematic structural diagram of the first gas-liquid separator of the present invention.

[0043] In the figure: 10-alkaline electrolytic cell; 11-gas-liquid mixed phase outlet on oxygen side; 12-gas-liquid mixed phase outlet on hydrogen side; 13-mixed circulating alkali solution inlet; 131-mixed alkali solution inlet line;

[0044] 20-first gas-liquid separator; 21-first gas-liquid mixed phase inlet; 22-first gas phase outlet; 221-first gas phase outlet line; 2211-demister; 23-first liquid phase outlet; 24-cyclone separation internals; 25-liquid separator plate;

[0045] 30- oxygen side gas-liquid separator; 31- second liquid phase inlet; 32- second gas phase outlet; 321- second gas phase outlet line; 322- first hydrogen sensor; 33- second liquid phase outlet;

[0046] 40-hydrogen side gas-liquid separator; 41-third gas-liquid mixed phase inlet; 42-third gas phase outlet; 421-third gas phase outlet line; 43-third liquid phase outlet;

[0047] 50-catalytic reactor; 51-catalytic reactor inlet line; 511-second hydrogen sensor; 512-blower; 52-first cavity; 521-first grid plate; 522-catalyst; 523-second grid plate; 53-catalytic reactor outlet line; 531-third hydrogen sensor; 54-condensate outlet line;

[0048] 61-first valve; 62-second valve; 63-third valve;

[0049] 71-first pipeline; 72-second pipeline; 73-third pipeline; 74-fourth pipeline; 75-fifth pipeline; 76-sixth pipeline; 77-seventh pipeline;

[0050] 80-Alkali circulation pump. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below in conjunction with specific implementation methods and examples. It should be understood that the following examples are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-substantial improvements and adjustments made by professionals and technicians in this field based on the content of the present invention still belong to the scope of protection of the present invention.

[0052] See also Figure 1 to Figure 4 The electrolytic hydrogen production system for deeply reducing the hydrogen content in oxygen of the present invention comprises an alkaline electrolytic cell 10, a first gas-liquid separator 20, an oxygen-side gas-liquid separator 30, a hydrogen-side gas-liquid separator 40 and an alkaline solution circulation pump 80;

[0053] The alkaline electrolytic cell 10 is provided with an oxygen side gas-liquid mixed phase outlet 11 at the top of the anode side, and a hydrogen side gas-liquid mixed phase outlet 12 at the top of the cathode side; a mixed alkali solution inlet 13 is provided at the bottom of the alkaline electrolytic cell 10, and a mixed alkali solution inlet line 131 is provided at the mixed alkali solution inlet 13, and an alkali solution circulation pump 80 is provided on the mixed alkali solution inlet line 131;

[0054] Continue to see Figure 4 The first gas-liquid separator 20 has a first gas-liquid mixed phase inlet 21 on one side, a first gas phase outlet 22 on the other side, and a first liquid phase outlet 23 at the bottom;

[0055] Continue to see Figure 1-2 The oxygen side gas-liquid separator 30 has a second liquid phase inlet 31 on one side, a second liquid phase outlet 33 on the other side, and a second gas phase outlet 32 ​​on the top;

[0056] A third gas-liquid mixed phase inlet 41 is provided on one side of the hydrogen side gas-liquid separator 40, a third liquid phase outlet 43 is provided on the other side, and a third gas phase outlet 42 is provided on the top;

[0057] The oxygen-side gas-liquid mixed phase outlet 11 is connected to the first gas-liquid mixed phase inlet 21 through the first pipeline 71; the first gas phase outlet 22 is provided with a first gas phase outlet line 221, and the first gas phase outlet line 221 is connected to an oxygen-hydrogen deep separation device through a pipeline, and the oxygen-hydrogen deep separation device includes a first valve assembly, a fan 512 and a catalytic reactor 50; the first valve assembly and the fan 512 are used to control the operating state of the oxygen-hydrogen deep separation device; the catalytic reactor 50 is filled with a catalyst 522 that promotes the reaction of hydrogen and oxygen;

[0058] A catalytic reactor inlet line 51 is provided on one side of the catalytic reactor 50, and a catalytic reactor outlet line 53 is provided on the other side;

[0059] The first gas phase outlet line 221 is connected to the catalytic reactor inlet line 51 through a pipeline; the first gas phase outlet line 221 is connected to the top of the oxygen side gas-liquid separator 30 through a second pipeline 72; the catalytic reactor outlet line 53 is connected to the oxygen side gas-liquid separator 30 through a third pipeline 73; the first liquid phase outlet 23 is connected to the second liquid phase inlet 31 through a fourth pipeline 74, and the second liquid phase outlet 31 is connected to the mixed alkali liquid inlet line 131 through a fifth pipeline 75. A second gas phase outlet line 321 is provided at the second gas phase outlet 32, and a first hydrogen sensor 322 for monitoring the hydrogen content in oxygen of the alkaline water electrolysis hydrogen production system is provided on the second gas phase outlet line 321;

[0060] The first valve assembly includes a first valve 61, a second valve 62 and a third valve 63; the first valve 61 is arranged on the catalytic reactor inlet line 51, the second valve 62 is arranged on the third pipeline 73, and the third valve 63 is arranged on the second pipeline 72; the fan 512 is arranged on the catalytic reactor inlet line 51; the state of the oxygen-hydrogen deep separation device can be controlled by controlling the states of the first valve 61, the second valve 62, the third valve 63 and the fan 512;

[0061] The hydrogen side gas-liquid mixed phase outlet 12 is connected to the third gas-liquid mixed phase inlet 41 through the sixth pipeline 76, the third liquid phase outlet 43 is connected to the mixed alkali liquid inlet line 131 through the seventh pipeline 77, and a third gas phase outlet line 421 is provided at the third gas phase outlet 42.

[0062] The present invention performs preliminary gas-liquid separation on the gas-liquid mixed liquid on the anode side of the alkaline electrolytic cell 10 by installing a first gas-liquid separator 20 before the oxygen-side gas-liquid separator 30, and a deep separation device for oxygen-hydrogen capable of deeply removing hydrogen from oxygen is connected to the gas phase outlet of the first gas-liquid separator 20; a first hydrogen sensor 322 for monitoring the hydrogen content in oxygen of the alkaline electrolytic hydrogen production system is arranged at the gas phase outlet of the oxygen-side gas-liquid separator 30, and when the alkaline electrode cell 10 is operated at a low load (less than 50% of the rated load) or when the first hydrogen sensor 322 detects that the alkaline electrolytic water When the hydrogen content in oxygen in the hydrogen production system is too high, the oxygen-hydrogen deep separation device is turned on (the first valve 61, the second valve 62 and the fan 512 are opened, and the third valve 63 is closed), so that the oxygen-side gas phase product separated by the first gas-liquid separator enters the catalytic reactor for deep dehydrogenation (catalytic dehydrogenation), deeply reducing the hydrogen content in oxygen in the oxygen-side gas phase product, and the oxygen-side gas phase product after catalytic dehydrogenation enters the oxygen-side gas-liquid separator to participate in secondary separation, thereby reducing the hydrogen content in oxygen in the alkaline water electrolysis hydrogen production system and improving the safety of the alkaline water electrolysis hydrogen production system.

[0063] When in use, the alkaline electrolytic cell 10 is first connected to a DC power supply, the positive electrode of the power supply is connected to the anode of the alkaline electrolytic cell 10, and the negative electrode of the power supply is connected to the cathode of the alkaline electrolytic cell 10; under the action of the DC power, the alkaline electrolyte in the alkaline electrolytic cell 10 becomes a gas-liquid mixed liquid containing a large number of fine bubbles; the gas-liquid mixed liquid on the anode side of the alkaline electrolytic cell 10 is pumped into the first gas-liquid separator 20 through the first pipeline 71 by the alkaline liquid circulation pump 80 for preliminary gas-liquid separation, and the oxygen side after the preliminary gas-liquid separation is The gas phase product enters the oxygen side gas-liquid separator 30 through the first gas phase outlet line 22 and the third pipeline 73, and the oxygen side alkali liquid enters the oxygen side gas-liquid separator 30 through the fourth pipeline 74 for secondary gas-liquid separation; the gas-liquid mixed liquid on the cathode side of the alkaline electrolytic cell 10 is pumped into the hydrogen side gas-liquid separator 40 through the sixth pipeline 76 by the alkali liquid circulation pump 80 for gas-liquid separation; the oxygen side gas phase product after the secondary gas-liquid separation is discharged through the second gas phase outlet line 321 and enters the next processing step (such as drying, pressurizing and collecting ); the hydrogen side gas phase product after gas-liquid separation is discharged through the third gas phase outlet line 421 and enters the next processing step (such as drying and pressurizing collection); the oxygen side alkali liquid after the secondary gas-liquid separation and the hydrogen side alkali liquid after the gas-liquid separation enter the mixed alkali liquid inlet line 131 through the second pipeline 72 and the seventh pipeline 77 respectively for mixing and then re-enter the alkaline electrolytic cell 10 to participate in the electrolysis reaction; when the alkaline electrode cell 10 is running under low load or when the first hydrogen sensor 322 detects that the hydrogen content in oxygen in the alkaline water electrolysis hydrogen production system is higher than 1.5%, the third valve 63 is closed, the first valve 61, the second valve 62 and the fan 512 are opened, so that the oxygen-hydrogen deep separation device starts to operate, and the fan 512 transports the oxygen side gas phase product separated by the first gas-liquid separator 20 to the catalytic reactor for catalytic dehydrogenation. When the first hydrogen sensor 322 detects that the hydrogen content in oxygen in the alkaline water electrolysis hydrogen production system is lower than 1%, the fan 512 is closed and the third valve 63 is opened to reduce energy consumption.

[0064] Continue to see Figure 2 In a preferred embodiment of the present invention, a demister 2211 is provided on the first gas phase outlet line 221 for removing liquid droplets from the oxygen side gas phase product separated by the first gas-liquid separator 20, and the design flow rate of the demister 2211 is 3.5-5.5 m / s.

[0065] The design flow rate of the demister 2211 is selected to be 3.5-5.5 m / s, which has a better effect in removing droplets.

[0066] Furthermore, in a preferred embodiment of the present invention, the first gas-liquid separator 20 is a centrifugal gas-liquid separator, such as Figure 4 As shown, the centrifugal gas-liquid separator has a cyclone separation internal part 24 and a liquid separation plate 25 inside, which is beneficial to the gas-liquid separation of the gas-liquid mixture.

[0067] Continue to see Figure 2 In a preferred embodiment of the present invention, a condensate outlet line 54 is provided at the bottom of the catalytic reactor 50 .

[0068] A condensate outlet line 54 is provided at the bottom of the catalytic reactor 50, and the condensate outlet line 54 is connected to the oxygen-side gas-liquid separator 30, so that the water generated in the catalytic reactor enters the oxygen-side gas-liquid separator from the bottom of the catalytic reactor in the form of condensate. Since the main reactions in the catalytic reactor are: (exothermic reaction),

[0069] The condensed water has a high temperature and enters the oxygen-side gas-liquid separator, which can increase the temperature of the alkaline electrolyte in the oxygen-side gas-liquid separator, reduce the solubility of hydrogen in the alkaline electrolyte, and further reduce the hydrogen content in the oxygen in the alkaline water electrolysis hydrogen production system.

[0070] Furthermore, the catalyst 522 is one or more of a HX-palladium catalyst (including a palladium catalyst with aluminum oxide or activated manganese oxide as a carrier), a platinum catalyst, and a silver catalyst.

[0071] Furthermore, the main particle size range of the catalyst 522 is 1 to 7 mm, and the amount used is 0.02 to 0.1 m 3 .

[0072] Continue to see Figure 2 In a preferred embodiment of the present invention, a second hydrogen sensor 511 is provided on the catalytic reactor inlet line 51 , and a third hydrogen sensor 531 is provided on the catalytic reactor outlet line 53 .

[0073] Hydrogen sensors are arranged before and after the catalytic reactor 50 to monitor the hydrogen content in oxygen at the inlet and outlet of the catalytic reactor 50, so as to determine whether the catalytic reactor 50 is operating normally.

[0074] See also Figure 3 In a preferred embodiment of the present invention, the catalytic reactor 50 has a first cavity 52, a catalyst 522 is filled in the first cavity 52, a first grid plate 521 is provided at the front end of the first cavity 52, and a second grid plate 523 is provided at the rear end (front and back in the present invention refer to the direction along the fluid flow).

[0075] It should be noted that the location of the alkali liquid circulation pump in the present invention includes but is not limited to the mixed alkali liquid inlet line 131. In order to improve the operating efficiency of the system, the alkali liquid circulation pump can be set on other pipelines, such as the first pipeline 71 and the sixth pipeline 76.

[0076] Continue to see Figure 1 to Figure 4 The electrolytic hydrogen production method for deeply reducing the hydrogen content in oxygen of the present invention adopts the electrolytic hydrogen production device for deeply reducing the hydrogen content in oxygen, and comprises the following steps:

[0077] S1. Under the action of direct current, the alkaline electrolyte in the alkaline electrolytic cell 10 becomes a gas-liquid mixture of a large number of fine bubbles;

[0078] S2. Under the action of the alkali liquid circulation pump 80, the gas-liquid mixture on the anode side of the alkaline electrolytic cell 10 enters the first gas-liquid separator 20 for preliminary gas-liquid separation, and the oxygen-side gas phase product and the oxygen-side alkali liquid after the preliminary separation enter the oxygen-side gas-liquid separator 30 for secondary gas-liquid separation; under the action of the alkali liquid circulation pump 80, the gas-liquid mixture on the cathode side of the alkaline electrolytic cell 10 enters the hydrogen-side gas-liquid separator 40 for gas-liquid separation;

[0079] S3. The oxygen-side gas phase product after secondary separation is discharged from the top of the oxygen-side gas-liquid separator 30 and enters the next processing step (such as drying and pressurizing collection); the oxygen-side alkali liquid after secondary separation re-enters the alkaline electrolytic cell 10 under the action of the alkali liquid circulation pump 80 to participate in electrolytic hydrogen production; the hydrogen-side gas phase product after passing through the gas-liquid separator is discharged from the top of the hydrogen-side gas-liquid separator 40 and enters the next processing step (such as drying and pressurizing collection), and the hydrogen-side alkali liquid after gas-liquid separation re-enters the alkaline electrolytic cell 10 under the action of the alkali liquid circulation pump 80 to participate in electrolytic hydrogen production;

[0080] S4. When the first hydrogen sensor 322 detects that the hydrogen content in oxygen in the alkaline water electrolysis hydrogen production system exceeds 1.5%, the oxygen-hydrogen deep separation device is opened by controlling the first valve group and the fan 512, and the oxygen-hydrogen deep separation device starts to operate, and the oxygen-side gas phase product separated by the first gas-liquid separator 20 is deeply dehydrogenated. The oxygen-side gas phase product after deep dehydrogenation enters the oxygen-side gas-liquid separator 30 to participate in secondary gas-liquid separation; when the first hydrogen sensor 322 detects that the hydrogen content in oxygen in the alkaline water electrolysis system is lower than 1%, the oxygen-hydrogen deep separation device is closed by controlling the first valve group and the fan to reduce energy consumption.

[0081] In a preferred embodiment of the present invention, in step S4, when the oxygen-hydrogen deep separation device is in operation, the air speed of the fan 512 is 2-10h -1 .

[0082] Control the air speed of fan 512 to 2-10h -1 The oxygen-side gas phase product separated by the first gas-liquid separator 20 is transported to the catalytic reactor 50, so that the oxygen and hydrogen in the gas phase product can contact the catalyst at a high superficial rate, thereby greatly improving the chemical reaction efficiency.

[0083] Example 1

[0084] The electrolytic hydrogen production system and method for deeply reducing the hydrogen content in oxygen of the present invention are used to prepare hydrogen. The specific process conditions are as follows: the current density of the alkaline electrolytic cell is 250A / m 2(10%), the circulation flow rate of alkaline electrolyte is 5L / min;

[0085] Under the action of direct current, the alkaline electrolyte in the alkaline electrolytic cell 10 becomes a gas-liquid mixture with a large number of fine bubbles; under the action of the alkaline liquid circulation pump 80, the gas-liquid mixture on the anode side of the alkaline electrolytic cell 10 enters the first gas-liquid separator 20 for preliminary gas-liquid separation, and the oxygen-side gas phase product after the preliminary separation enters the catalytic reactor for catalytic dehydrogenation under the action of the fan, and the oxygen-side alkaline liquid enters the oxygen-side gas-liquid separator for secondary gas-liquid separation; wherein, the air speed of the fan is 2.5h -1 The catalyst 522 in the catalytic reactor 50 is alumina palladium catalyst particles, the main particle size range of which is 3-5mm, and the amount of catalyst used in the reactor is 0.03m 3 ; The oxygen-side gaseous product after catalytic dehydrogenation enters the oxygen-side gas-liquid separator 30 to participate in secondary gas-liquid separation; under the action of the alkali liquid circulation pump 80, the gas-liquid mixture on the cathode side of the alkaline electrolyzer 10 enters the hydrogen-side gas-liquid separator 40 for gas-liquid separation; the oxygen-side gaseous product after secondary separation is discharged from the top of the oxygen-side gas-liquid separator 30 and enters the next processing step (such as drying and pressurizing collection); the oxygen-side alkali liquid after secondary separation re-enters the alkaline electrolyzer 10 under the action of the alkali liquid circulation pump 80 to participate in electrolytic hydrogen production; the hydrogen-side gaseous product after passing through the gas-liquid separator is discharged from the top of the hydrogen-side gas-liquid separator 40 and enters the next processing step (such as drying and pressurizing collection), and the hydrogen-side alkali liquid after gas-liquid separation re-enters the alkaline electrolyzer 10 under the action of the alkali liquid circulation pump 80 to participate in electrolytic hydrogen production.

[0086] The gas phase product at the gas phase outlet of the oxygen-side gas-liquid separator 30 is collected as sample 1, and the hydrogen content in the oxygen of sample 1 is measured by a gas chromatograph.

[0087] Example 2

[0088] The difference between this embodiment and embodiment 1 is that the air speed of the fan is different. The air speed of the fan in this embodiment is 5h -1 .

[0089] The gas phase product at the gas phase outlet of the oxygen-side gas-liquid separator 30 is collected as sample 2, and the hydrogen content in the oxygen of sample 2 is measured by a gas chromatograph.

[0090] Example 3

[0091] The difference between this embodiment and embodiment 1 is that the air speed of the fan is different. The air speed of the fan in this embodiment is 7.5h -1 .

[0092] The gas phase product at the gas phase outlet of the oxygen-side gas-liquid separator 30 is collected as sample 3, and the hydrogen content in the oxygen of sample 3 is measured by a gas chromatograph.

[0093] Example 4

[0094] The difference between this embodiment and embodiment 1 is that the air speed of the fan is different. The air speed of the fan in this embodiment is 10h -1 .

[0095] The gas phase product at the gas phase outlet of the oxygen-side gas-liquid separator 30 is collected as sample 4, and the hydrogen content in the oxygen of sample 4 is measured by a gas chromatograph.

[0096] Example 5

[0097] The difference between this embodiment and embodiment 1 is that the current density of the alkaline electrolytic cell is different. The current density of the alkaline electrolytic cell in this embodiment is 1000A / m 2 (40%).

[0098] The gas phase product at the gas phase outlet of the oxygen-side gas-liquid separator 30 is collected as sample 5, and the hydrogen content in the oxygen of sample 5 is measured by a gas chromatograph.

[0099] Example 6

[0100] The difference between this embodiment and embodiment 5 is that the air speed of the fan is different. The air speed of the fan in this embodiment is 5h -1 .

[0101] The gas phase product at the gas phase outlet of the oxygen-side gas-liquid separator 30 is collected as sample 6, and the hydrogen content in the oxygen of sample 6 is measured by a gas chromatograph.

[0102] Example 7

[0103] The difference between this embodiment and embodiment 5 is that the air speed of the fan is different. The air speed of the fan in this embodiment is 7.5h -1 .

[0104] The gas phase product at the gas phase outlet of the oxygen-side gas-liquid separator 30 is collected as sample 7, and the hydrogen content in the oxygen of sample 7 is measured by a gas chromatograph.

[0105] Example 8

[0106] The difference between this embodiment and embodiment 5 is that the air speed of the fan is different. The air speed of the fan in this embodiment is 10h -1 .

[0107] The gas phase product at the gas phase outlet of the oxygen-side gas-liquid separator 30 is collected as sample 8, and the hydrogen content in the oxygen of sample 8 is measured by a gas chromatograph.

[0108] Comparative Example 1

[0109] The difference between this comparative example and Examples 1 to 8 is that the alkaline water electrolysis hydrogen production device does not have a first gas-liquid separator installed, nor does it use the oxygen-hydrogen deep separation device of the present invention, but only uses conventional cathode-side and anode-side gas-liquid separators. The current density of the alkaline electrolytic cell in this comparative example is 250 A / m 2 (40%) The gas phase product at the gas phase outlet of the oxygen-side gas-liquid separator 30 is collected as sample 9, and the hydrogen content in the oxygen of sample 9 is measured by a gas chromatograph.

[0110] Comparative Example 2

[0111] The difference between this comparative example and Examples 1 to 8 is that the alkaline water electrolysis hydrogen production device does not have a first gas-liquid separator installed, nor does it use the oxygen-hydrogen deep separation device of the present invention, but only uses conventional cathode-side and anode-side gas-liquid separators. The current density of the alkaline electrolytic cell in this comparative example is 1000 A / m 2 (40%) The gas phase product at the gas phase outlet of the oxygen-side gas-liquid separator 30 is collected as sample 10, and the hydrogen content in the oxygen of sample 10 is measured by a gas chromatograph.

[0112] The hydrogen contents in oxygen of samples 1 to 10 were measured and are shown in Table 1 below.

[0113] Table 1

[0114] sample <![CDATA[Current density (A / m 2 )]]> Oxygen space velocity (h-1) Hydrogen content in oxygen 1 250 2.5 1.75 2 250 5 1.69 3 250 7.5 1.34 4 250 10 1.21 5 1000 2.5 0.69 6 1000 5 0.67 7 1000 7.5 0.49 8 1000 10 0.37 9 250 / 1.81 10 1000 / 0.73

[0115] It can be seen from the above table that the deep separation device of oxygen and hydrogen of the present invention has a fan speed of 2-10h -1 It can effectively reduce the hydrogen content in oxygen in the alkaline water electrolysis hydrogen production system, and the air speed of the fan 512 is 10h -1 When the hydrogen content in oxygen of the alkaline water electrolysis hydrogen production system decreases the most, 250A / m 2 At low load, the hydrogen content in oxygen decreased from 1.81% to 1.21%, a decrease of 33%; 1000A / m 2 Under the load, the hydrogen content in oxygen decreased from 0.73% to 0.37%, a decrease of 49% ((the hydrogen content in oxygen at the outlet of the original gas-liquid separator - the hydrogen content in oxygen at the outlet of the gas-liquid separator after installation) / the hydrogen content in oxygen at the outlet of the original gas-liquid separator).

[0116] It should be noted that the above-described embodiments should be understood as illustrative rather than limiting the scope of protection of the present invention. For those skilled in the art, non-essential improvements and adjustments made to the present invention without departing from the essence and scope of the present invention still fall within the scope of protection of the present invention.

Claims

1. An electrolytic hydrogen production system for deeply reducing the hydrogen content in oxygen, comprising an alkaline electrolytic cell, an oxygen-side gas-liquid separator, a hydrogen-side gas-liquid separator, and an alkaline liquid circulation pump; The alkaline electrolytic cell is provided with an oxygen side gas-liquid mixed phase outlet at the top of the anode side, and a hydrogen side gas-liquid mixed phase outlet at the top of the cathode side; It is characterized in that A first hydrogen sensor is provided at the gas phase outlet of the oxygen-side gas-liquid separator for monitoring the hydrogen content in oxygen in the alkaline water electrolysis hydrogen production system; A first gas-liquid separator is installed in front of the oxygen-side gas-liquid separator, and the first gas-liquid separator is connected to the oxygen-side gas-liquid mixed phase outlet, and is used to perform preliminary gas-liquid separation on the gas-liquid mixed liquid received from the anode side of the alkaline electrolyzer; the gas phase outlet and the liquid phase outlet of the first gas-liquid separator are both connected to the oxygen-side gas-liquid separator through pipelines; the gas phase outlet of the first gas-liquid separator is connected to an oxygen-hydrogen deep separation device through a pipeline, and the oxygen-hydrogen deep separation device includes a first valve assembly, a power mechanism and a catalytic reactor, and the gas phase outlet of the catalytic reactor is connected to the oxygen-side gas-liquid separator through a pipeline; the first valve assembly and the power mechanism are used to control the operating state of the oxygen-hydrogen deep separation device, and the catalytic reactor is used to catalytically dehydrogenate the gas phase product from the gas phase outlet of the first gas-liquid separator.

2. The electrolytic hydrogen production system for deeply reducing the hydrogen content in oxygen according to claim 1, characterized in that: The first gas-liquid separator is provided with a first gas-liquid mixed phase inlet on one side, a first gas phase outlet on the other side, and a first liquid phase outlet at the bottom; The oxygen-side gas-liquid separator is provided with a second liquid phase inlet on one side, a second liquid phase outlet on the other side, and a second gas phase outlet on the top; The hydrogen-side gas-liquid separator is provided with a third gas-liquid mixed phase inlet on one side, a third liquid phase outlet on the other side, and a third gas phase outlet on the top; The catalytic reactor is provided with a catalytic reactor inlet line on one side and a catalytic reactor outlet line on the other side; A mixed alkali solution inlet is provided at the bottom of the alkaline electrolytic cell, and a mixed alkali solution inlet line is provided at the mixed alkali solution inlet; The oxygen-side gas-liquid mixed phase outlet is connected to the first gas-liquid mixed phase inlet through a first pipeline; a first gas phase outlet is provided at the first gas phase outlet, and the first gas phase outlet is connected to the catalytic reactor inlet through a pipeline; the first gas phase outlet is connected to the top of the oxygen-side gas-liquid separator through a second pipeline; the catalytic reactor outlet is connected to the oxygen-side gas-liquid separator through a third pipeline; the first liquid phase outlet is connected to the second liquid phase inlet through a fourth pipeline, the second liquid phase outlet is connected to the mixed alkali liquid inlet through a fifth pipeline, and a second gas phase outlet is provided at the second gas phase outlet; The hydrogen side gas-liquid mixed phase outlet is connected to the third gas-liquid mixed phase inlet through the sixth pipeline, the third liquid phase outlet is connected to the mixed alkali liquid inlet line through the seventh pipeline, and the third gas phase outlet is provided with a third gas phase outlet line.

3. The electrolytic hydrogen production system for deeply reducing the hydrogen content in oxygen according to claim 2, characterized in that: The power mechanism is a fan, and the fan is arranged on the inlet line of the catalytic reactor.

4. The electrolytic hydrogen production system for deeply reducing the hydrogen content in oxygen according to claim 2, characterized in that: The first valve assembly includes a first valve, a second valve and a third valve. The first valve is arranged on the inlet line of the catalytic reactor, the second valve is arranged on the outlet line of the catalytic reactor or the third pipeline, and the third valve is arranged on the second pipeline.

5. The electrolytic hydrogen production system for deeply reducing the hydrogen content in oxygen according to claim 1, characterized in that: A condensate outlet line is provided at the bottom of the catalytic reactor, and the condensate outlet line is communicated with the oxygen-side gas-liquid separator.

6. The electrolytic hydrogen production system for deeply reducing the hydrogen content in oxygen according to claim 1, characterized in that: A demister is provided on the first gas phase outlet line, and the demister is used to remove liquid droplets in the oxygen-side gas phase product separated by the first gas-liquid separator. The designed flow rate of the demister is 3.5-5.5 m / s.

7. The electrolytic hydrogen production system for deeply reducing the hydrogen content in oxygen according to claim 1, characterized in that: A second hydrogen sensor is provided on the inlet line of the catalytic reactor, and a third hydrogen sensor is provided on the outlet line of the catalytic reactor.

8. The electrolytic hydrogen production system for deeply reducing the hydrogen content in oxygen according to claim 1, characterized in that: The catalytic reactor comprises a first cavity filled with a catalyst for promoting the reaction of hydrogen and oxygen; a first grid plate is arranged at the front end of the first cavity, and a second grid plate is arranged at the rear end.

9. A method for producing hydrogen by electrolysis for deeply reducing the hydrogen content in oxygen, using the device for producing hydrogen by electrolysis for deeply reducing the hydrogen content in oxygen according to any one of claims 1 to 8, comprising the following steps: S1. Under the action of direct current, the alkaline electrolyte in the alkaline electrolytic cell becomes a gas-liquid mixture of a large number of fine bubbles; S2. Under the action of the alkali liquid circulation pump, the gas-liquid mixture on the anode side of the alkaline electrolytic cell enters the first gas-liquid separator for preliminary gas-liquid separation, and the oxygen-side gas phase product and the oxygen-side alkali liquid after the preliminary separation enter the oxygen-side gas-liquid separator for secondary gas-liquid separation; under the action of the alkali liquid circulation pump, the gas-liquid mixture on the cathode side of the alkaline electrolytic cell enters the hydrogen-side gas-liquid separator for gas-liquid separation; S3. The oxygen-side gas phase product after secondary separation is discharged from the top of the oxygen-side gas-liquid separator and enters the next processing step; the oxygen-side alkali liquid after secondary separation re-enters the alkaline electrolytic cell under the action of the alkali liquid circulation pump to participate in electrolytic hydrogen production; the hydrogen-side gas phase product after passing through the gas-liquid separator is discharged from the top of the hydrogen-side gas-liquid separator and enters the next processing step, and the hydrogen-side alkali liquid after gas-liquid separation re-enters the alkaline electrolytic cell under the action of the alkali liquid circulation pump to participate in electrolytic hydrogen production; S4. When the alkaline electrode cell is operating under low load or when the first hydrogen sensor detects that the content of hydrogen in oxygen in the alkaline water electrolysis hydrogen production system exceeds 1.5%, the oxygen-hydrogen deep separation device is opened by controlling the first valve group and the power mechanism, and the oxygen-hydrogen deep separation device starts to operate, and the oxygen-side gas phase product separated by the first gas-liquid separator is deeply dehydrogenated. The oxygen-side gas phase product after the deep dehydrogenation enters the oxygen-side gas-liquid separator to participate in secondary gas-liquid separation; when the first hydrogen sensor detects that the content of hydrogen in oxygen in the alkaline water electrolysis system is lower than 1%, the oxygen-hydrogen deep separation device is closed by controlling the first valve assembly and the power mechanism.

10. The method for producing hydrogen by electrolysis for deeply reducing the hydrogen content in oxygen according to claim 9, characterized in that: In step S4, when the oxygen-hydrogen deep separation device is running, the air speed of the fan is 2-10h -1 .

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