Alkaline water electrolysis hydrogen production system, gas-liquid separation device and application of gas-liquid separation device

Abstract

The invention discloses an alkaline water electrolysis hydrogen production system, a gas-liquid separation device and application of the gas-liquid separation device. The gas-liquid separation device comprises a separation tower, and a gas-liquid separation distributor, a washing carrier, a washing water distributor, a defoaming filter screen and a cooler which are sequentially arranged in the separation tower from bottom to top, a fluid inlet and a fluid outlet are formed in the lower part of the separation tower; a gas outlet is formed in the top of the separation tower; the gas-liquid separation distributor is used for carrying out gas-liquid separation on the gas-liquid mixed fluid introduced into the separation tower; washing water sprayed from the washing water distributor is distributed on the surface of the washing carrier, so that liquid carried in the gas separated from the gas-liquid separation distributor is in reverse contact with the washing water distributed on the surface of the washing carrier, and the liquid carried in the gas is removed; the defoaming filter screen is used for removing liquid carried in the gas; the cooler is used for cooling the gas and the liquid carried in the gas, so that the liquid separated out after cooling falls back to the separation tower under the action of gravity, and the gas-liquid separation efficiency and the separation purity are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic hydrogen production equipment, and particularly relates to an alkaline water electrolysis hydrogen production system, a gas-liquid separation device and their applications. Background Art

[0002] Currently, in the process of seeking carbon zero-emission, water electrolysis hydrogen production, as one of the most potential technologies capable of realizing the conversion between renewable energy such as solar energy and wind energy and hydrogen energy, has received extensive social attention. Using renewable energy for water electrolysis to produce hydrogen is of great significance for both realizing the transformation of the energy structure and carbon zero-emission.

[0003] In industrial alkaline electrolyzers for water electrolysis hydrogen production, approximately 30% KOH aqueous solution is used as the electrolyte. Two electrodes are immersed in the KOH alkaline solution, and a diaphragm is used to separate them in the middle. When a certain direct current is applied, the water in the electrolyte is electrolyzed, hydrogen is generated at the cathode, and oxygen is generated at the anode. Subsequently, high-purity hydrogen and oxygen are produced through a gas-liquid separation system. The process flow chart is as Figure 1 shown as follows:

[0004] The hydrogen generated at the cathode is sent to the hydrogen separator in the gas-liquid separation frame together with the electrolyte, and gas-liquid separation is carried out under the action of gravity. The separated hydrogen is sent to the hydrogen cooler to exchange heat with circulating water for cooling, further separating the moisture in the hydrogen. The separated water returns to the hydrogen separator by gravity. After the hydrogen is washed to remove entrained liquid droplets, it is sent to the hydrogen water separator on the hydrogen side. Then, the hydrogen is sent to the hydrogen purification unit for purification after being stabilized by the liquid level regulating valve at the outlet. The alkali-containing liquid phase separated by the hydrogen water separator is sent out of the device for treatment. Similarly, the oxygen generated at the anode is sent to the oxygen separator in the gas-liquid separation frame together with the electrolyte, and gas-liquid separation is carried out under the action of gravity. The separated oxygen is sent to the oxygen cooler to exchange heat with circulating water for cooling, further separating the moisture in the oxygen. The separated moisture returns to the oxygen separator by gravity. After the oxygen is washed to remove entrained liquid droplets, it is sent to the oxygen water separator on the oxygen side. Then, the oxygen is sent to the oxygen purification unit for purification or directly vented after being stabilized by the pressure regulating valve at the outlet. The alkali-containing liquid phase separated by the oxygen water separator is sent out of the device for treatment.

[0005] The liquid levels of the hydrogen separator and the oxygen separator maintain the system pressure balance through the bottom connecting pipe. The alkali liquor separated at the bottoms of the two separators is first passed through an alkali liquor filter to remove solid impurities, and then pressurized by an alkali liquor circulation pump and sent to an alkali liquor heat exchanger to exchange heat with circulating water for temperature reduction, and then returned to the electrolytic cell for continuous electrolysis.

[0006] The raw water from the demineralized water plant is sent to the raw water tank and the lye tank through the makeup water valve. When the liquid levels in the hydrogen separator and the oxygen separator are low, the raw water is injected into the scrubbers on the hydrogen (oxygen) side through the makeup water pump for hydrogen (oxygen) gas scrubbing. The scrubber is a water seal structure, and the excess makeup water flows into the hydrogen (oxygen) separator through the overflow pipe and enters the lye circulation system together with the lye, thus achieving the purpose of replenishing water. Summary of the Invention

[0007] In order to improve the gas-liquid separation efficiency, reduce the size of the separation equipment, improve the separation purity, further shorten the process flow and simplify the process equipment, and facilitate the recovery of lye and water, the present invention proposes an alkaline water electrolysis hydrogen production system, a gas-liquid separation device and its application.

[0008] In a first aspect, an embodiment of the present invention provides an alkaline water electrolysis hydrogen production system, which may include: at least one electrolytic cell, a circulation pump, and two gas-liquid separation devices, one of the gas-liquid separation devices being an oxygen separation device and the other being a hydrogen separation device;

[0009] Wherein, the gas-liquid separation device may include: a separation tower, and a gas-liquid separation distributor, a washing carrier, a washing water distributor, a demisting filter screen, and a cooler sequentially arranged from bottom to top inside the separation tower; a fluid inlet and a fluid outlet are provided at the lower part of the separation tower, and a gas outlet is provided at the top of the separation tower; the cathode of the electrolytic cell is communicated with the fluid inlet of the hydrogen separation device, and the anode of the electrolytic cell is communicated with the fluid inlet of the oxygen separation device; the bottoms of the hydrogen separation device and the oxygen separation device are communicated; the fluid outlets of the hydrogen separation device and the oxygen separation device are communicated with the electrolytic cell through pipelines and the circulation pump to form an electrolyte recovery path;

[0010] The gas-liquid separation distributor is used for separating the gas-liquid mixed fluid introduced from the electrolytic cell into the separation tower; the washing water sprayed from the washing water distributor is distributed on the surface of the washing carrier, so that the liquid carried in the gas separated from the gas-liquid separation distributor contacts the washing water distributed on the surface of the washing carrier in a countercurrent manner and removes the liquid carried in the gas; the demisting filter screen is used for removing the liquid carried in the gas; the cooler is used for cooling the gas and the liquid carried in the gas, so that the liquid precipitated after cooling falls back into the separation tower under the action of gravity.

[0011] Optionally, the oxygen separation device may further include: a pressure transmitter and a pressure regulating valve connected to the gas outlet;

[0012] The pressure transmitter is connected to the separation tower of the oxygen separation device and is used to monitor the pressure inside the separation tower; the pressure regulating valve is electrically connected to the pressure transmitter and is used to adjust the flow rate of the gas outlet based on the pressure inside the separation tower monitored by the pressure transmitter.

[0013] Optionally, the system may further include: a first liquid level transmitter connected to the separation tower of the oxygen separation device, a second liquid level transmitter connected to the separation tower of the hydrogen separation device, a first liquid level regulating valve connected to the gas outlet of the hydrogen separation device, and a liquid level difference transmitter electrically connected to the first liquid level transmitter, the second liquid level transmitter, and the first liquid level regulating valve respectively;

[0014] The first liquid level transmitter is used to monitor the liquid level in the separation tower of the oxygen separation device, and the second liquid level transmitter is used to monitor the liquid level in the separation tower of the hydrogen separation device; the liquid level difference transmitter is used to determine the liquid level difference between the oxygen separation device and the hydrogen separation device based on the liquid level monitored by the first liquid level transmitter and the liquid level monitored by the second liquid level transmitter; the first liquid level regulating valve is used to adjust the flow rate of the gas outlet of the hydrogen separation device based on the liquid level difference determined by the liquid level difference transmitter so as to adjust the liquid levels of the oxygen separation device and the hydrogen separation device.

[0015] Optionally, an electrolyte supply inlet and an electrolyte supply pipeline connected to the electrolyte supply inlet are further provided on the separation tower of the hydrogen separation device;

[0016] Wherein, the electrolyte supply inlet is located below the gas-liquid separation distributor of the hydrogen separation device; the electrolyte supply pipeline is externally connected to an electrolyte supply device, and a second liquid level regulating valve electrically connected to the second liquid level transmitter is provided on the electrolyte supply pipeline, and the second liquid level regulating valve adjusts the feed amount of the electrolyte supplied to the separation tower of the hydrogen separation device based on the liquid level in the separation tower of the hydrogen separation device monitored by the second liquid level transmitter.

[0017] Optionally, the gas-liquid separation device may further include: a washing water supply pipeline connected to the washing water distributor, a flow regulating valve and a flow transmitter are installed on the washing water supply pipeline, and the flow regulating valve is electrically connected to the flow transmitter;

[0018] The washing water supply pipeline is used to be externally connected to a washing water supply device, and the flow regulating valve and the flow transmitter are used to adjust the feed amount of the washing water entering the washing water distributor.

[0019] Optionally, the system may further include: an alkali solution cooler located between the circulation pump and the electrolytic cell; the alkali solution cooler is used to externally connect to circulating cooling water, and is used to cool the liquid separated in the gas-liquid separation device and recycle it to the electrolytic cell.

[0020] Optionally, the system may further include: a temperature transmitter and a temperature regulating valve electrically connected to the temperature transmitter;

[0021] The temperature transmitter is installed on the outlet pipeline of the alkali solution cooler for monitoring the liquid temperature at the outlet of the alkali solution cooler; the temperature regulating valve is installed on the inlet pipeline of the alkali solution cooler for adjusting the flow rate of the cooling water entering the alkali solution cooler based on the liquid temperature monitored by the temperature transmitter.

[0022] Optionally, the system may further include: an alkali solution filter, and the alkali solution filter is respectively connected to the fluid outlets of the hydrogen separation device and the oxygen separation device and the circulation pump through pipelines, and is used to filter the liquids separated by the hydrogen separation device and the oxygen separation device.

[0023] In a second aspect, an embodiment of the present invention provides a gas-liquid separation device, which may include: a separation tower and a gas-liquid separation distributor, a washing carrier, a washing water distributor, a demisting filter screen, and a cooler sequentially arranged in the separation tower from bottom to top; a fluid inlet and a fluid outlet are opened at the lower part of the separation tower, and a gas outlet is arranged at the top of the separation tower;

[0024] Wherein, the gas-liquid separation distributor is used for gas-liquid separation of the gas-liquid mixed fluid introduced into the separation tower; the washing water sprayed from the washing water distributor is distributed on the surface of the washing carrier, so that the liquid carried in the gas separated from the gas-liquid separation distributor contacts the washing water distributed on the surface of the washing carrier in a reverse direction and removes the liquid carried in the gas; the demisting filter screen is used to remove the liquid carried in the gas; the cooler is used to cool the gas and the liquid carried in the gas, so that the liquid precipitated after cooling falls back into the separation tower under the action of gravity.

[0025] Optionally, the gas-liquid separation distributor is at least one of the following distributors: a double-row blade distributor, a tubular distributor, a single tangential distributor, and a double tangential distributor.

[0026] Optionally, the washing carrier is: packing or a tray.

[0027] Optionally, the washing water distributor is at least one of the following distributors: a trough-type liquid distributor, a nozzle-type liquid distributor, and a collecting tank-type liquid distributor.

[0028] Optionally, the demisting filter screen is at least one of the following: vane demisting filter screen, wire mesh demisting filter screen, and metal-resin woven wire mesh demisting filter screen.

[0029] In a third aspect, an embodiment of the present invention provides an application of the gas-liquid separation device described in the second aspect in an alkaline water electrolysis hydrogen production system.

[0030] The beneficial effects of the above technical solutions provided in the embodiments of the present invention at least include:

[0031] An alkaline water electrolysis hydrogen production system, a gas-liquid separation device and its application are provided in the embodiments of the present invention. The gas-liquid separation device can improve the separation efficiency of gas and liquid and the separation purity through the cooperation of various components; at the same time, as an integrated separation device, it is beneficial to shorten the process flow, reduce the size of the separation device, and thus save the floor area; furthermore, the liquid separated by the device is easy to recover, reducing the subsequent treatment process.

[0032] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the written description and the drawings.

[0033] The technical solutions of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0034] The drawings are used to provide a further understanding of the present invention, and constitute a part of the description. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0035] Figure 1 is a structural diagram of an existing alkaline water electrolysis hydrogen production system;

[0036] Figure 2 is a structural diagram of the gas-liquid separation device provided in the embodiment of the present invention;

[0037] Figure 3 is a structural diagram of alkaline water electrolysis hydrogen production provided in the embodiment of the present invention;

[0038] Among them, 1 - gas-liquid separation device; 2 - electrolytic cell; 3 - circulation pump; 4 - oxygen separation device; 5 - hydrogen separation device; 6 - lye cooler; 7 - temperature transmitter; 8 - temperature regulating valve; 9 - lye filter.

[0039] 11 - Separation tower; 12 - Gas - liquid separation distributor; 13 - Washing carrier; 14 - Washing water distributor; 15 - Demisting filter screen; 16 - Cooler; 111 - Fluid inlet; 112 - Fluid outlet; 113 - Gas outlet; 17 - Washing water supply pipeline; 18 - Flow regulating valve; 19 - Flow transmitter;

[0040] 41 - Pressure transmitter; 42 - Pressure regulating valve; 43 - First liquid level transmitter; 51 - Second liquid level transmitter; 52 - First liquid level regulating valve; 53 - Liquid level difference transmitter; 54 - Electrolyte supply inlet; 55 - Electrolyte supply pipeline; 56 - Second liquid level regulating valve. Detailed implementation manners

[0041] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0042] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "far", "near", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and should not be construed as indicating or implying relative importance.

[0043] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0044] The inventor found that in the water electrolysis hydrogen production device applied in the prior art, the separation of gas and electrolyte is carried out in the hydrogen (oxygen) separator, and usually the gravity sedimentation method is adopted for separation, that is, relying on the action of gravity, using the density difference between gas and liquid to make them move relatively and settle. This method has a slow separation speed and poor separation effect, and may cause the following adverse factors to the water electrolysis hydrogen production device:

[0045] (1) The hydrogen-oxygen separator equipment has a relatively large volume, resulting in a relatively large floor area for the gas-liquid separation system.

[0046] (2) The gas-liquid separation effect is poor, causing the electrolyte returned to the electrolytic cell to contain gas. The cathode-side electrolyte containing hydrogen and the anode-side electrolyte containing oxygen are mixed in the electrolytic cell, which not only reduces the purity of the final product gas but also poses a safety hazard to the electrolytic cell.

[0047] (3) The gas-liquid separation effect is poor, which will cause the gas phase in the hydrogen-oxygen separator to entrain the electrolyte into downstream equipment, increasing the complexity of the subsequent treatment process.

[0048] In addition, in the gas-liquid separation system of the current water electrolysis hydrogen production device, most are skid-mounted equipment. The hydrogen (oxygen) separator, hydrogen (oxygen) cooler, hydrogen (oxygen) scrubber, and hydrogen (oxygen) gas-water separator inside are all independent split-type equipment. The large number of equipment, large equipment volume, and complex pipeline connections between equipment will all result in a large occupied space for the gas-liquid separation system. And there are multiple welded connections, resulting in a relatively long integrated installation period. Using the split-type equipment process, the alkali liquor generated after gas cooling is not easy to recover, causing a large loss of alkali liquor in the water electrolysis hydrogen production device.

[0049] Since hydrogen and oxygen exist almost in the form of bubbles in the electrolyte and have very small sizes, quickly and efficiently separating the gas from the electrolyte is of great significance to the water electrolysis hydrogen production device. With the large-scale, large-scale, and cost-saving development of the water electrolysis hydrogen production device, higher and higher requirements are put forward for the equipment investment and occupied space of the required gas-liquid separation system. In view of the above problems, the present invention is proposed to provide an alkaline water electrolysis hydrogen production system, a gas-liquid separation device, and their applications that can overcome or at least partially solve the above problems.

[0050] Example 1

[0051] In Example 1 of the present invention, a gas-liquid separation device is provided. Refer to Figure 2As shown in the figure, the gas-liquid separation device 1 may include: a separation tower 11, and a gas-liquid separation distributor 12, a washing carrier 13, a washing water distributor 14, a demisting filter screen 15, and a cooler 16 which are sequentially arranged from bottom to top inside the separation tower 11; a fluid inlet 111 and a fluid outlet 112 are provided at the lower part of the separation tower 11, and a gas outlet 113 is provided at the top of the separation tower 11; wherein, the gas-liquid separation distributor 12 is used for separating the gas-liquid mixed fluid introduced into the separation tower 11 into gas and liquid; the washing water sprayed from the washing water distributor 14 is distributed on the surface of the washing carrier 13, so that the liquid carried in the gas separated from the gas-liquid separation distributor 12 contacts the washing water distributed on the surface of the washing carrier 13 in a countercurrent manner and removes the liquid carried in the gas; the demisting filter screen 15 is used for removing the liquid carried in the gas; the cooler 16 is used for cooling the gas and the liquid carried in the gas, so that the liquid precipitated after cooling falls back into the separation tower 11 under the action of gravity.

[0052] The working process of the above-mentioned gas-liquid separation device in the embodiment of the present invention is as follows: The gas-liquid mixed fluid enters the interior of the separation tower from the fluid inlet at the lower part of the separation tower. During the rising process, after being efficiently separated by the gas-liquid separation distributor, the separated liquid falls to the bottom of the separation tower, and the separated gas and a small amount of liquid carried by the gas continue to rise; the washing water sprayed from the washing water distributor is distributed on the surface of the washing carrier, and the rising gas and the small amount of liquid carried by it are in countercurrent contact with the washing water on the surface of the washing carrier to remove the small amount of liquid carried. As the gas rises, the demisting filter screen further captures the tiny liquid droplets in the gas; at the same time, the washing water is in a state of gaseous saturated water or tiny water droplets here. After being cooled by the cooler, the liquid precipitates and falls back into the separation tower under the action of gravity to achieve efficient gas-liquid separation.

[0053] The above-mentioned gas-liquid separation device provided in the embodiment of the present invention can improve the separation efficiency of gas and liquid and the separation purity through the cooperation of various components; at the same time, as an integrated separation device, the device is beneficial to shortening the process flow, reducing the size of the separation device, and thus saving the floor area; furthermore, the device is easy to recycle the separated liquid and reduces the subsequent treatment process.

[0054] In an optional embodiment, the above-mentioned gas-liquid separation distributor is an efficient distributor, which can achieve efficient separation of the gas-liquid mixed fluid, for example, efficient separation of the gas and electrolyte introduced into the electrolytic cell in the hydrogen production system. In this embodiment, the gas-liquid separation distributor is at least one of the following distributors: a double-row vane distributor, a tubular distributor, a single tangential distributor, and a double tangential distributor.

[0055] In another alternative embodiment, the washing carrier is: packing or tray. The above-mentioned packing / tray contacts with the washing water to remove the liquid (such as electrolyte) entrained in the gas. When the packing / tray contacts with the washing water, the washing water is distributed on the surface of the packing / tray. The packing / tray is the place for gas-liquid contact, where mass transfer and heat transfer occur inside the packing. The fluid inlet is arranged at the lower end of the packing device, and the packing is for further gas-liquid separation of the liquid in the rising gas. Compared with the prior art, when the gas directly contacts the sprayed washing water to separate the liquid carried in the gas, due to the lack of a place for washing and separation (directly washing in the cavity), the separation effect in the cavity is poor.

[0056] It should be noted that in this embodiment, the packing can be structured packing or random packing, and the packing type can be selected according to the scale of the gas-liquid separation device and the characteristics of the gas-liquid mixed fluid to be separated.

[0057] In another alternative embodiment, the above-mentioned washing water distributor is used to evenly distribute the washing water on the surface of the packing / tray, and the washing water distributor is at least one of the following distributors: trough-type liquid distributor, nozzle-type liquid distributor, and oil sump-type liquid distributor. In specific implementation, in the hydrogen production system, the above-mentioned washing water can be pure water or raw material water (alkaline electrolyte water).

[0058] In another alternative embodiment, the above-mentioned demisting filter screen is a high-efficiency demister mechanism, which can further capture small liquid droplets in the gas and improve the gas-liquid separation efficiency. The above-mentioned demisting filter screen is at least one of the following: vane-type demisting filter screen, wire mesh demisting filter screen, and metal-resin woven wire mesh demisting filter screen.

[0059] In an alternative embodiment, the above-mentioned cooler is externally connected to circulating cooling water, which is used to cool the separated gas and the saturated water carried in the gas, so as to further precipitate the liquid and let it fall back to the separation tower under the action of gravity, further improving the gas-liquid separation efficiency.

[0060] Based on the same inventive concept, an application of the above-mentioned gas-liquid separation device in an alkaline water electrolysis hydrogen production system is also provided in the embodiments of the present invention.

[0061] The beneficial effects and specific descriptions of the application of the above-mentioned gas-liquid separation device in the alkaline water electrolysis hydrogen production system in the embodiments of the present invention can refer to the relevant introduction of the above-mentioned gas-liquid separation device, and will not be repeated here in the embodiments of the present invention.

[0062] Embodiment 2

[0063] In the second embodiment of the present method, an alkaline water electrolysis hydrogen production system is provided. Refer to Figure 3As shown in the figure, the system may include: at least one electrolytic cell 2, a circulation pump 3, and two gas-liquid separation devices 1 in the first embodiment above, where one gas-liquid separation device 1 is an oxygen separation device 4 and the other gas-liquid separation device 1 is a hydrogen separation device 5; wherein, in combination with Figure 2 As shown in the figure, the gas-liquid separation device 1 may include: a separation tower 11, and a gas-liquid separation distributor 12, a washing carrier 13, a washing water distributor 14, a demisting filter screen 15, and a cooler 16 that are sequentially arranged from bottom to top inside the separation tower 11; a fluid inlet 111 and a fluid outlet 112 are provided at the lower part of the separation tower 11, and a gas outlet 113 is provided at the top of the separation tower 11; the cathode of the electrolytic cell 2 is communicated with the fluid inlet 111 of the hydrogen separation device 5, and the anode of the electrolytic cell 2 is communicated with the fluid inlet 111 of the oxygen separation device 4; the bottoms of the hydrogen separation device 5 and the oxygen separation device 4 are communicated; the fluid outlets 112 of the hydrogen separation device 5 and the oxygen separation device 4 are communicated with the electrolytic cell 2 through a pipeline (the line in the figure) and the circulation pump 3 to form an electrolyte recovery path; the gas-liquid separation distributor 12 is used for gas-liquid separation of the gas-liquid mixed fluid introduced from the electrolytic cell 2 into the separation tower 11; the washing water sprayed from the washing water distributor 14 is distributed on the surface of the washing carrier 13, so that the liquid carried in the gas separated from the gas-liquid separation distributor 12 is in reverse contact with the washing water distributed on the surface of the washing carrier 13 and the liquid carried in the gas is removed; the demisting filter screen 15 is used for removing the liquid carried in the gas; the cooler 16 is used for cooling the gas and the liquid carried in the gas, so that the liquid separated out after cooling falls back into the separation tower 11 under the action of gravity.

[0064] It should be noted that the above hydrogen separation device and oxygen separation device in the embodiment of the present invention can perform gas-liquid separation on the gas-liquid mixed fluid electrolyzed by a single electrolytic cell, or can perform gas-liquid separation on the gas-liquid mixed fluids electrolyzed by multiple electrolytic cells at the same time. It should also be noted that the bottoms of the hydrogen separation device and the oxygen separation device are communicated, which ensures the connection of the liquid levels separated at the bottom and ensures the pressure balance between the hydrogen separation device and the oxygen separation device.

[0065] In the above alkaline water electrolysis hydrogen production system provided in the embodiment of the present invention, for the existing large-scale hydrogen production equipment, the use of a system composed of multiple gas-liquid separation devices for gas-liquid separation is avoided. Through the integrated integration and non-standard design of the gas-liquid separation device in this system, at least one electrolytic cell corresponds to a set of gas-liquid separation integrated equipment, achieving double intensification of land occupation and investment.

[0066] The working process of the above alkaline water electrolysis hydrogen production system provided in the embodiment of the present invention is as follows:

[0067] The hydrogen generated at the cathode of the electrolyzer is sent together with the alkaline solution (alkaline water electrolysis solution) into the separation tower of the hydrogen separation device, and gas-liquid separation is carried out through the highly efficient gas-liquid separation distributor arranged in the separation tower. The separated hydrogen enters the washing section in the tower and contacts the raw water sprayed downward reversely on the surface of the packing / tray, so as to remove the alkaline solution entrained in the hydrogen. A raw water distributor is arranged above the packing / tray to make the raw water evenly distributed on the packing / tray. After passing through the washing section of the packing / tray and removing the entrained alkaline solution, the hydrogen enters the highly efficient demisting filter screen at the upper part of the tower top to further capture liquid droplets (mostly raw water), and then is sent to the hydrogen cooler to exchange heat with circulating water for cooling, further separating the liquid in the hydrogen (mainly raw water). The separated liquid returns to the hydrogen separation tower by gravity, and the hydrogen is sent to the hydrogen purification unit for purification after being stabilized by the liquid level regulating valve at the gas outlet.

[0068] Similarly, the oxygen generated at the anode of the electrolyzer is sent together with the alkaline solution into the separation tower of the oxygen separation device, and gas-liquid separation is carried out through the highly efficient gas-liquid separation distributor arranged at the tower inlet. The separated oxygen enters the washing section in the tower and contacts the raw water sprayed downward reversely on the surface of the packing / tray, so as to remove the alkaline solution entrained in the oxygen. A raw water distributor is arranged above the packing / tray to make the raw water evenly distributed on the packing / tray. After passing through the washing section of the packing / tray and removing the entrained alkaline solution, the oxygen enters the highly efficient demisting filter screen at the tower top to further capture liquid droplets, and then is sent to the oxygen cooler to exchange heat with circulating water for cooling, further separating the liquid in the oxygen. The separated liquid returns to the oxygen separation tower by gravity, and the oxygen is sent to the oxygen purification unit for purification or directly vented after being stabilized by the pressure regulating valve at the outlet.

[0069] In the above alkaline water electrolysis hydrogen production system provided in the embodiment of the present invention, by setting the hydrogen separation device and the oxygen separation device, and arranging components such as a gas-liquid separation distributor, a packing / tray, a washing water distributor, a demisting filter screen and a filter in the separation tower, the separation efficiency of the gas and the electrolyte is improved, the size of the gas-liquid separation equipment is reduced, and the purity of the gas-phase product is improved; at the same time, by forming an integrated device with the hydrogen cooler and the oxygen cooler, it is beneficial to shorten the process flow, simplify the process equipment, and is easy to recover the alkaline solution and water. In the large-scale application of the system, about 60% of the land occupation can be saved by the system provided by the present invention, which will have outstanding advantages for the construction and application of large-scale hydrogen production systems in areas rich in renewable energy in the future.

[0070] In an alternative embodiment, referring to Figure 2 and Figure 3As shown, the oxygen separation device 4 may further include: a pressure transmitter 41 and a pressure regulating valve 42 connected to the gas outlet 113; the pressure transmitter 41 is connected to the separation tower 11 of the oxygen separation device 4 for monitoring the pressure inside the separation tower 11; the pressure regulating valve 42 is electrically connected to the pressure transmitter 41 for adjusting the flow rate of the gas outlet 113 based on the pressure inside the separation tower 11 monitored by the pressure transmitter 41.

[0071] In the oxygen separation device in the implementation of the present invention, the pressure transmitter provided on the separation tower and the pressure regulating valve at the gas outlet form a control loop to regulate the gas pressure of the entire system to achieve air pressure balance by regulating the flow rate of oxygen at the gas outlet.

[0072] In another alternative embodiment, referring to Figure 3 As shown, the alkaline water electrolysis hydrogen production system may further include: a first liquid level transmitter 43 connected to the separation tower 11 of the oxygen separation device 4, a second liquid level transmitter 51 connected to the separation tower 11 of the hydrogen separation device 5, a first liquid level regulating valve 52 connected to the gas outlet 113 of the hydrogen separation device 5, and a liquid level difference transmitter 53 electrically connected to the first liquid level transmitter 43, the second liquid level transmitter 51, and the first liquid level regulating valve 52 respectively; the first liquid level transmitter 43 is used for monitoring the liquid level in the separation tower 11 of the oxygen separation device 4, and the second liquid level transmitter 51 is used for monitoring the liquid level in the separation tower 11 of the hydrogen separation device 5; the liquid level difference transmitter 53 is used for determining the liquid level difference between the oxygen separation device 4 and the hydrogen separation device 5 based on the liquid level monitored by the first liquid level transmitter 43 and the liquid level monitored by the second liquid level transmitter 51; the first liquid level regulating valve 52 is used for adjusting the flow rate of the gas outlet 113 of the hydrogen separation device 5 based on the liquid level difference determined by the liquid level difference transmitter 53 to adjust the liquid levels of the oxygen separation device 4 and the hydrogen separation device 5.

[0073] In this embodiment, the liquid level transmitters provided on the separation towers of the hydrogen separation device and the oxygen separation device, the liquid level difference measured by the two, and the liquid level regulating valve at the gas outlet of the hydrogen separation device form a control loop to adjust the liquid level balance between the oxygen separation device and the hydrogen separation device in the system.

[0074] In another alternative embodiment, referring to Figure 3As shown, an electrolyte supply inlet 54 and an electrolyte supply pipeline 55 connected to the electrolyte supply inlet 54 are further provided on the separation tower of the hydrogen separation device 5; among them, the electrolyte supply inlet 54 is located below the gas-liquid separation distributor 12 of the hydrogen separation device 5; the electrolyte supply pipeline 55 is externally connected to an electrolyte supply device (not shown in the figure), and a second liquid level regulating valve 56 electrically connected to the second liquid level transmitter 51 is provided on the electrolyte supply pipeline 55. The second liquid level regulating valve 56 adjusts the feed amount of the electrolyte supplied to the separation tower 11 of the hydrogen separation device 5 based on the liquid level in the separation tower 11 of the hydrogen separation device 5 monitored by the second liquid level transmitter 51.

[0075] In this embodiment, the above-mentioned second liquid level regulating valve adjusts the feed amount of the supplied electrolyte, and the above-mentioned first liquid level regulating valve adjusts the discharge flow rate of hydrogen. Under their combined action, the liquid levels in the separation towers of the hydrogen separation device and the oxygen separation device are adjusted. In specific implementation, when the liquid levels in the hydrogen separation device and the oxygen separation device are low, raw water is injected into the separation tower of the hydrogen separation device through a feed water pump and enters the lye circulation system together with the lye, so as to achieve the purpose of supplementing raw water. The hydrogen separation device is provided with a liquid level transmitter, and the raw water supply pipeline is provided with a liquid level regulating valve. The two constitute a control loop for controlling the feed amount of raw water.

[0076] In another alternative embodiment, referring to Figure 3 As shown, the gas-liquid separation device 1 may further include: a washing water supply pipeline 17 connected to the washing water distributor 14, a flow regulating valve 18 and a flow transmitter 19 are installed on the washing water supply pipeline 17, and the flow regulating valve 18 is electrically connected to the flow transmitter 19; the washing water supply pipeline 17 is used to be externally connected to a washing water supply device (not shown in the figure), and the flow regulating valve 18 and the flow transmitter 19 are used to adjust the feed amount of the washing water entering the washing water distributor 14.

[0077] A flowmeter and a flow regulating valve are provided on the above-mentioned pipeline to adjust the feed amount of raw water (washing water), and control the raw water to be evenly sprayed onto the washing carrier to contact the gas reversely to further achieve gas-liquid separation.

[0078] In another alternative embodiment, referring to Figure 3 As shown, the alkaline water electrolysis hydrogen production system may further include: a lye cooler 6 located between the circulation pump 3 and the electrolytic cell 2; the lye cooler 6 is used to be externally connected to circulating cooling water (not shown in the figure), and is used to cool the liquid separated in the gas-liquid separation device 1 and recycle it to the electrolytic cell 2.

[0079] In another specific embodiment, referring to Figure 3As shown, the alkaline water electrolysis hydrogen production system may further include: a temperature transmitter 7 and a temperature regulating valve 8 electrically connected to the temperature transmitter 7; the temperature transmitter 7 is installed on the outlet pipeline of the lye cooler 6 for monitoring the liquid temperature at the outlet of the lye cooler 6; the temperature regulating valve 8 is installed on the inlet pipeline of the lye cooler 6 for adjusting the flow rate of the cooling water entering the lye cooler 6 based on the liquid temperature monitored by the temperature transmitter 7.

[0080] In an embodiment of the present invention, the separated liquid is pressurized by a circulation pump and then sent to a lye cooler, where it exchanges heat with circulating cooling water (or other cooling media) to cool down and then returns to the electrolytic cell to continue electrolysis. A temperature transmitter is provided at the outlet of the lye cooler, and a temperature regulating valve is provided on the inlet pipeline of the lye cooler to form a control loop for controlling the temperature of the electrolyte entering the electrolytic cell (for example, 75 °C).

[0081] In another alternative embodiment, referring to Figure 3 As shown, the alkaline water electrolysis hydrogen production system may further include: a lye filter 9, and the lye filter 9 is respectively connected in communication with the fluid outlets 112 of the hydrogen separation device 5 and the oxygen separation device 4 and the circulation pump 3 through pipelines for filtering the liquids separated by the hydrogen separation device 5 and the oxygen separation device 4.

[0082] The above-mentioned lye filtering device can filter out solid impurities in the liquid, not only avoiding chemical reactions between cations or anions and solid impurities during electrolysis of the lye and reducing the hydrogen production efficiency, but also improving the safety factor for subsequent electrolysis of the lye.

[0083] In specific implementation, the lye separated by the hydrogen separation device and the oxygen separation device first passes through the lye filter to remove solid impurities, and then after being pressurized by the circulation pump, it is sent to the lye cooler, where it exchanges heat with circulating cooling water (or other cooling media) to cool down and then returns to the electrolytic cell to continue electrolysis.

[0084] In this embodiment, the liquids (lye) separated by the above-mentioned hydrogen separation device and oxygen separation device can be respectively filtered, cooled and then recycled to the corresponding electrodes of the electrolytic cell for further recycling, or can be jointly filtered, cooled and then recycled to the electrolytic cell for further electrolysis and recycling. The present invention does not make specific limitations in this regard.

[0085] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. The present disclosure is not limited to the exact structure described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present disclosure is only limited by the appended claims. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. An alkaline water electrolysis hydrogen production system, characterized in that, it includes: at least one electrolytic cell, a circulation pump and two gas-liquid separation devices, one of the gas-liquid separation devices being an oxygen separation device and the other being a hydrogen separation device; wherein, the gas-liquid separation device includes: a separation tower and a gas-liquid separation distributor, a washing carrier, a washing water distributor, a demisting filter screen and a cooler which are sequentially arranged from bottom to top inside the separation tower; a fluid inlet and a fluid outlet are provided at the lower part of the separation tower, and a gas outlet is provided at the top of the separation tower; the cathode of the electrolytic cell is communicated with the fluid inlet of the hydrogen separation device, and the anode of the electrolytic cell is communicated with the fluid inlet of the oxygen separation device; the bottoms of the hydrogen separation device and the oxygen separation device are communicated; the fluid outlets of the hydrogen separation device and the oxygen separation device are communicated with the electrolytic cell through pipelines and the circulation pump to form an electrolyte recovery path; the gas-liquid separation distributor is used for separating the gas-liquid mixed fluid introduced from the electrolytic cell into the separation tower into gas and liquid; the washing water sprayed from the washing water distributor is distributed on the surface of the washing carrier, so that the liquid carried in the gas separated from the gas-liquid separation distributor is in reverse contact with the washing water distributed on the surface of the washing carrier to remove the liquid carried in the gas; the demisting filter screen is used for removing the liquid carried in the gas; the cooler is used for cooling the gas and the liquid carried in the gas, so that the liquid precipitated after cooling falls back into the separation tower under the action of gravity.

2. The system according to claim 1, characterized in that, the oxygen separation device further includes: a pressure transmitter and a pressure regulating valve connected to the gas outlet; the pressure transmitter is communicated with the separation tower of the oxygen separation device and is used for monitoring the pressure inside the separation tower; the pressure regulating valve is electrically connected to the pressure transmitter and is used for adjusting the flow rate of the gas outlet based on the pressure inside the separation tower monitored by the pressure transmitter.

3. The system according to claim 1, characterized in that, it further includes: a first liquid level transmitter communicated with the separation tower of the oxygen separation device, a second liquid level transmitter communicated with the separation tower of the hydrogen separation device, a first liquid level regulating valve connected to the gas outlet of the hydrogen separation device, and a liquid level difference transmitter electrically connected to the first liquid level transmitter, the second liquid level transmitter and the first liquid level regulating valve respectively; the first liquid level transmitter is used for monitoring the liquid level in the separation tower of the oxygen separation device, and the second liquid level transmitter is used for monitoring the liquid level in the separation tower of the hydrogen separation device; the liquid level difference transmitter is used for determining the liquid level difference between the oxygen separation device and the hydrogen separation device based on the liquid level monitored by the first liquid level transmitter and the liquid level monitored by the second liquid level transmitter; the first liquid level regulating valve is used for adjusting the flow rate of the gas outlet of the hydrogen separation device based on the liquid level difference determined by the liquid level difference transmitter to adjust the liquid levels of the oxygen separation device and the hydrogen separation device.

4. The system according to claim 3, wherein, an electrolyte supply inlet and an electrolyte supply pipeline connected to the electrolyte supply inlet are further provided on the separation tower of the hydrogen separation device; wherein, the electrolyte supply inlet is located below the gas-liquid separation distributor of the hydrogen separation device; the electrolyte supply pipeline is externally connected to an electrolyte supply device, and a second liquid level regulating valve electrically connected to the second liquid level transmitter is provided on the electrolyte supply pipeline, and the second liquid level regulating valve adjusts the feed amount of the electrolyte supplied to the separation tower of the hydrogen separation device based on the liquid level in the separation tower of the hydrogen separation device monitored by the second liquid level transmitter.

5. The system according to claim 1, wherein, the gas-liquid separation device further includes: a washing water supply pipeline connected to the washing water distributor, and a flow regulating valve and a flow transmitter are installed on the washing water supply pipeline, and the flow regulating valve is electrically connected to the flow transmitter; the washing water supply pipeline is used to be externally connected to a washing water supply device, and the flow regulating valve and the flow transmitter are used to adjust the feed amount of the washing water entering the washing water distributor.

6. The system according to any one of claims 1 to 5, wherein, further includes: an alkali liquor cooler located between the circulation pump and the electrolytic cell; the alkali liquor cooler is used to be externally connected to circulating cooling water, and is used to cool the liquid separated in the gas-liquid separation device and recycle it to the electrolytic cell.

7. The system according to claim 6, wherein, further includes: a temperature transmitter and a temperature regulating valve electrically connected to the temperature transmitter; the temperature transmitter is installed on the outlet pipeline of the alkali liquor cooler and is used to monitor the liquid temperature at the outlet of the alkali liquor cooler; the temperature regulating valve is installed on the inlet liquid pipeline of the alkali liquor cooler and is used to adjust the flow rate of the cooling water entering the alkali liquor cooler based on the liquid temperature monitored by the temperature transmitter.

8. The system according to any one of claims 1 to 5, wherein, further includes: an alkali liquor filter, and the alkali liquor filter is communicated with the fluid outlets of the hydrogen separation device and the oxygen separation device and the circulation pump through pipelines respectively, and is used to filter the liquids separated by the hydrogen separation device and the oxygen separation device.

9. A gas-liquid separation device, wherein, includes: a separation tower and a gas-liquid separation distributor, a washing carrier, a washing water distributor, a demisting filter screen and a cooler which are sequentially arranged in the separation tower from bottom to top; a fluid inlet and a fluid outlet are provided at the lower part of the separation tower, and a gas outlet is provided at the top of the separation tower; Among them, the gas-liquid separation distributor is used to separate the gas-liquid mixed fluid introduced into the separation tower; the washing water sprayed from the washing water distributor is distributed on the surface of the washing carrier, so that the liquid carried in the gas separated from the gas-liquid separation distributor contacts the washing water distributed on the surface of the washing carrier in a countercurrent manner and removes the liquid carried in the gas; the demisting filter screen is used to remove the liquid carried in the gas; the cooler is used to cool the gas and the liquid carried in the gas, so that the liquid precipitated after cooling falls back into the separation tower under the action of gravity.

10. The gas-liquid separation device according to claim 9, characterized in that the gas-liquid separation distributor is at least one of the following distributors: double-row blade distributor, tube distributor, single tangential distributor and double tangential distributor; the washing carrier is: packing or tray; the washing water distributor is at least one of the following distributors: trough-type liquid distributor, nozzle-type liquid distributor and oil sump-type liquid distributor; and / or the demisting filter screen is at least one of the following: blade demisting filter screen, wire mesh demisting filter screen, metal-resin woven wire mesh demisting filter screen.

11. Application of a gas-liquid separation device as claimed in claim 9 or 10 in an alkaline water electrolysis hydrogen production system.

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