JP2016204698A - Electrolysis system, and electrolysis method using electrolysis system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrolysis system that achieves a process design where a liquid residue at the bottom of an electrolysis tank used in the electrolysis system is removed to the most and all of an electrolyte, an electrolytic product, and water are automatically discharged from the electrolysis tank in a shutdown time of the electrolysis tank, prevents corrosion of an electrode and the electrolysis tank, has a compact structure, and can be installed in a narrow space and easily transported.SOLUTION: An electrolysis tank is installed at an upper stage of an electrolysis system and a circulation tank for supplying and circulating an electrolyte to the electrolysis tank is installed at a lower stage. The circulation tank serves also as a recovery tank of the electrolyte. A supply manifold for supplying the electrolyte to the electrolysis tank from the circulation tank is installed at a lower position than the bottom face of the electrolysis tank and serves also as a recovery manifold of the electrolyte. When the operation of the electrolysis tank is stopped, all electrolytes in the electrolysis tank are recovered due to gravity without using a pump.SELECTED DRAWING: Figure 3

Description

The present invention relates to an electrolytic system that electrolyzes an electrolytic solution composed of an aqueous solution and / or pure water to generate hydrogen gas from a cathode, and an electrolysis method using the electrolytic system.
In particular, the present invention uses a solid polymer type (hereinafter referred to as “SPE type”) water electrolysis tank, an alkaline water electrolysis tank or a salt electrolysis tank, and other halide electrolysis tanks, and electrolysis comprising an alkaline aqueous solution or an alkaline halide aqueous solution. The present invention relates to an electrolysis system that electrolyzes liquid or pure water to generate hydrogen gas from a cathode, and an electrolysis method using the electrolysis system.

Since hydrogen is a secondary energy that is suitable for storage and transportation and has a small environmental load, there is an interest in a hydrogen energy system using hydrogen as an energy carrier. At present, hydrogen is mainly produced by steam reforming of fossil fuels. From the viewpoint of global warming and fossil fuel depletion, the importance of electrolysis systems for hydrogen production using renewable energy as a power source is important. Sex is increasing.
Examples of the electrolysis system include an electrolysis system using an SPE type water electrolysis tank, an electrolysis system using an alkaline water electrolysis tank, and an electrolysis system using a halide electrolysis tank such as a salt electrolysis tank.

In an electrolysis system using an SPE type water electrolyzer, an SPE type water electrolyzer using a solid polymer electrolyte membrane is usually used in order to decompose pure water and generate hydrogen (and oxygen). In the SPE type water electrolyzer, an anode catalyst layer and a cathode catalyst layer are provided on both sides of the SPE to form a membrane electrode assembly, and a power feeder is provided on both sides of the membrane electrode assembly. Thus, a unit cell is configured (Patent Document 1).
Therefore, in the electrolytic stack in which a plurality of unit cells are stacked, voltage is applied to both ends in the stacking direction, and water is supplied to the anode-side power feeding body. For this reason, water is decomposed and hydrogen ions (protons) are generated on the anode side of the electrolyte membrane / electrode structure, and the hydrogen ions permeate the solid polymer electrolyte membrane and move to the cathode side to bond with electrons. Thus, hydrogen is produced. On the other hand, on the anode side, oxygen generated together with hydrogen is discharged from the electrolytic stack together with excess water. The following advantages can be expected from SPE water electrolysis.

1) Pure water can be decomposed directly. That is, dissolution, neutralization, and removal of the electrolyte, which are indispensable in the alkaline aqueous solution electrolysis method, are unnecessary, and the capacity of the sample water is unlimited in principle.
2) The surface in direct contact with the membrane is the movement of protons (H ⁺ ), and the entire surface of the electrode is not covered by bubbles, so that electrolysis can be performed with a large current and the electrolysis time can be shortened.
3) Hydrogen gas and oxygen gas are generated separately on both sides of the SPE film. In general, in SPE-type water electrolysis, a cation exchange membrane that transmits protons (H ⁺ ) is used. Therefore, separation of the gas generated from the anode and the cathode is performed by an ion exchange membrane, and the purity of the gas depends on the gas diffusion coefficient with respect to the ion exchange membrane. Unlike the diaphragm, the ion exchange membrane does not have mechanical pores penetrating the membrane, and the membrane surface is coated with an electrode catalyst. Accordingly, since gas diffusion is suppressed, a relatively high purity gas can be obtained, so that the gas can be easily processed.
However, when hydrogen is produced by SPE water electrolysis, although it can be applied to the production of small-scale hydrogen, it is not suitable for large-scale treatment. Since the electrolytic solution used is pure water, current does not flow through the electrolytic solution. Therefore, it is necessary to strongly squeeze the solid polymer film as a component with an anode and a cathode at a surface pressure corresponding to 20 to 30 kg / cm ² . Therefore, each member of the electrolytic cell is required to have high strength, and it is not practical to secure a large reaction area of 1 m ² or more in view of economy and operability. Not suitable for manufacturing methods.
On the other hand, when large-scale hydrogen production is carried out by water electrolysis, it is said that alkaline water electrolysis using cheap materials such as iron light metals such as nickel is more suitable than SPE type water electrolysis using noble metals and diamond electrodes. Yes.

In an electrolysis system using an alkaline water electrolysis tank, a nickel-based material that is stable in a high-concentration alkaline aqueous solution is used as an oxygen generating anode for alkaline water electrolysis, and a nickel-based electrode is used in alkaline water electrolysis using a stable power source. Has been reported to have a lifetime of over ten years. The electrode reactions at both electrodes are as follows.
Anodic reaction: 2OH ⁻ → H ₂ O + 1/2 O ₂ + 2e ⁻ (1)
Cathodic reaction: 2H ₂ O + 2e ⁻ → H ₂ + 2OH ⁻ (2)
The higher the concentration of the aqueous alkali solution, the higher the temperature, the higher the conductivity, but the higher the corrosivity, the higher the operating temperature is suppressed to about 80-90 ° C. Through the development of electrolytic cell constituent materials and various piping materials that can withstand high temperature and high concentration alkaline aqueous solution, the development of low resistance diaphragms, and electrodes with an enlarged surface area to provide a catalyst, the electrolysis performance has a current density of 0.3 to 0.4 A. / Cm ² , it is improved to about 1.7 to 1.9 V (electrolysis efficiency 78 to 87%).
However, in the case of using renewable energy as a power source, deterioration of Ni anode performance due to severe start / stop and severe conditions such as load fluctuations is a problem. The reason for this is that nickel is stable as a divalent hydroxide in an alkaline aqueous solution, and it is thermodynamically known that the oxidation reaction of nickel metal proceeds near the oxygen generation reaction potential. It is presumed that the following nickel oxide formation reaction proceeds.

Ni + 2OH ⁻ → Ni (OH) ₂ + 2e ⁻ (3)
Oxidized to trivalent and tetravalent as the potential increases. As a reaction formula:
Ni (OH) ₂ + OH ⁻ → NiOOH + H ₂ O + e ⁻ (4)
_{^{NiOOH + OH - → NiO 2 +}} H 2 O + e - (5)

Since the nickel oxide formation reaction and the reduction reaction proceed on the metal surface, the detachment of the electrode catalyst formed thereon is promoted. When power for electrolysis is not supplied, electrolysis is stopped and the nickel anode is maintained at an electrode potential lower than the oxygen generation potential (1.23 V vs. RHE). It is maintained at a higher potential than the hydrogen generating cathode (0.00 V vs. RHE) as the counter electrode, and electromotive force is generated by these chemical species in the cell. The anode potential is maintained at a low potential as the battery reaction proceeds, that is, the oxide reduction reaction is promoted according to the formulas (3), (4), and (5). Since such a battery reaction leaks through a common pipe when a large cell is assembled, such a current prevention technique is always a matter to be noted. As one of the measures, there is a measure to keep a minute current flowing at the time of stoppage. However, for that purpose, special power supply control is required, and oxygen and hydrogen are always generated. In order to avoid the reverse current state intentionally, it is possible to prevent such a battery reaction by draining the liquid immediately after the stop, but it is assumed that it is operated with electric power with large output fluctuations such as regenerative energy. In some cases, it is not an appropriate treatment.
Although nickel-based batteries use such oxides and hydroxides as active materials, it is preferable to suppress the activity of such nickel materials in alkaline water electrolysis.

Conventionally, as a catalyst layer of an anode for oxygen generation used in alkaline water electrolysis, at least one of platinum group metal, platinum group metal oxide, valve metal oxide, iron group oxide, and lanthanide group metal oxide Ingredients are used. Other anode catalysts include nickel-based alloys such as Ni—Co and Ni—Fe, nickel, Raney nickel with an increased surface area, and spinel-based Co ₃ O ₄ , NiCo ₂ O ₄ , and perovskite-based ceramic materials. Also known are conductive oxides such as LaCoO ₃ and LaNiO ₃ , noble metal oxides, and oxides composed of lanthanide group metals and noble metals.
As an anode for oxygen generation used for alkaline water electrolysis, nickel itself is resistant and is used in actual machines, but the oxygen generation overvoltage is relatively high at about 350 mV. Therefore, an active anode coating with a small oxygen overvoltage is required. For example, a nickel plating electrode containing sulfur is used as an anode for water electrolysis.

  Further, as an oxygen generating anode used for alkaline water electrolysis using a high concentration aqueous alkali solution, an anode in which a lithium-containing nickel oxide layer is previously formed on the surface of a nickel substrate is known (Patent Document 2).

  In an electrolysis system using a halide electrolyzer such as a salt electrolyzer, a noble metal or noble metal oxide is used to prevent the nickel substrate from deteriorating due to an oxidation reaction under a reverse current condition in a hydrogen generating cathode in an alkaline aqueous solution. It is disclosed that an intermediate layer mainly composed of nickel oxide is formed between a negative electrode catalyst made of a product and a nickel base (Patent Document 3). In order to form an intermediate layer, the substrate is fired at a relatively low temperature of 350 ° C. to 550 ° C., and such an intermediate layer is an intermediate layer for stabilizing the catalyst layer, and serves as a catalyst layer of the electrode. In addition, it cannot be used, and moreover, it can be used for oxygen generation anodes used for alkaline water electrolysis using high-concentration alkaline aqueous solution, particularly for the effect under power fluctuations. Te can not possibly imagine or bring what action and effect as a catalyst layer of the electrode.

JP 2002-38289 A British Patent No. 864457 JP 2000-239882 A

The conventional electrolysis system has the following problems regardless of which type of electrolytic cell is used.
(1) When a large amount of water is treated by electrolysis to produce a large amount of hydrogen, it is necessary to perform continuous operation. However, when the continuous operation is stopped, there are the following two dangers.
A. B) Risk of explosion. Risk of Corrosion of Electrode and Electrolyzer Explosion is the one that reaches the explosion limit of hydrogen and causes an explosion when the anticorrosion rectifier is energized to prevent the corrosion of the electrode.
This is because, in normal electrolysis, a large excess of gas is generated at the electrode, so the amount of hydrogen permeated by gas diffusion that crosses over the membrane is relatively small and can be ignored. This is because the amount of hydrogen gas in the crossover gas diffusion is not negligible during operation at, so that unless an appropriate system gas purge or replacement is performed, the hydrogen gas explosion region is reached.
However, there are many cases in which it is necessary to discharge the liquid in the electrolytic cell when the operation is stopped. However, in the conventional method, the electrolytic solution in the electrolytic cell (in the cell) must be discharged by a pump. However, it was difficult to build a compact system.
When the electrolyte solution in the electrolytic cell cannot be discharged naturally and the electrolyte solution is partially retained inside the electrolytic cell, the electrode is immersed in the liquid reservoir. When various precious metal coatings are applied, a local battery reaction due to a galvanic battery reaction occurs and corrosion of the Ni base material occurs. The actual corrosion reaction depends on the reaction rate, and there are various cases of the corrosion situation.
(2) When a large amount of hydrogen is to be produced, the electrolysis system becomes large, equipment becomes large, and it cannot be stored in a limited space, such as a container, package unit or skid mount. However, it was difficult to install an electrolysis system.
(3) Hydrogen is a secondary energy that is suitable for storage and transportation and has a low environmental impact. However, it is a hydrogen society to design a compact electrolysis system and introduce a concept that can be easily installed according to the local space to be operated. It is also one of the challenges toward realization. As a hydrogen production apparatus, separate large-scale plants and small-scale plants are required to be designed separately. In particular, in a small-scale plant, the transportability of the system is also important. It is also necessary to consider transporting a complete system as an emergency energy supply system.

  The present invention eliminates the above-mentioned problems, eliminates as much as possible that a liquid pool can be formed at the bottom of the electrolytic cell when the electrolytic cell used in the electrolytic system is stopped, and naturally discharges the electrolytic cell. Process design that can discharge all electrolytes, electrolytic products, water, etc. can be performed, corrosion of electrodes and electrolytic cells is prevented, and the structure is compact, so that it is narrow in both cases during normal times and disasters. An object of the present invention is to provide a space-saving electrolytic system that can be installed in a space and can be easily transported, moved, transported, or stationary.

In order to achieve the above object, the first solving means of the present invention is an electrolysis comprising an anode chamber for accommodating an anode, a cathode chamber for accommodating a cathode, and a diaphragm partitioning the anode chamber and the cathode chamber. In an electrolytic system that generates hydrogen gas from the cathode by electrolyzing an electrolytic solution consisting of an aqueous solution and / or pure water by an electrolytic cell in which a plurality of units are stacked,
The electrolytic cell housed in the upper stage of the electrolysis system;
In order to circulate the electrolyte and / or pure water to the anode chamber and the cathode chamber, a circulation tank housed in the lower stage of the electrolysis system;
A driving device for circulating and driving the electrolyte and / or water;
A supply tank for supplying electrolyte and / or water into the circulation tank;
A supply manifold connected to the lower part of the electrolytic cell or below the electrolytic cell;
A supply nozzle provided at the bottom of the anode chamber and the cathode chamber of the electrolytic cell;
A supply tube connected between the supply nozzle and the supply manifold;
A discharge manifold connected to the top of the electrolytic cell;
A discharge nozzle provided above the anode chamber and the cathode chamber of the electrolytic cell;
A discharge tube connected between the discharge nozzle and the discharge manifold;
An anode-side gas-liquid separator and a cathode-side gas-liquid separator connected to the discharge manifold;
A gas discharge line for gas-liquid separation into the electrolyte and / or water and product gas by the anode-side gas-liquid separator and cathode-side gas-liquid separator,
A circulation line for circulating the electrolyte and / or water separated by the anode-side gas-liquid separator and the cathode-side gas-liquid separator to the circulation tank;
While generating hydrogen gas from the cathode and continuing the electrolysis while circulating the electrolytic solution and / or water separated into gas and liquid to a circulation tank by the circulation line, The electrolytic solution is recovered by its own weight in the circulation tank from the supply nozzle through the supply tube and the supply manifold.

  In order to achieve the above object, the second solving means of the present invention is the electrolytic cell, the circulation tank, the supply tank, the drive device, the supply manifold, the discharge manifold, the anode side gas-liquid separation device, and It is an object of the present invention to provide an electrolysis system characterized in that a cathode side gas-liquid separator, the gas discharge line and the circulation line are all housed in a predetermined space.

  According to a third solution of the present invention, in order to achieve the above object, the defined space is at least one of a container, a package unit or a skid mount, a truck loading unit, a transport container, or a stationary space-saving system. It is to provide an electrolysis system characterized by being one.

  In order to achieve the above-mentioned object, the fourth solving means in the present invention is that the electrolytic cell comprises an SPE type water electrolytic cell, supplying pure water into the supply tank, and supplying the pure water to the electrolytic cell. The electrolytic gas supplied to both the electrolytic chambers of the anode chamber and the cathode chamber and discharged from the gas discharge line through the gas-liquid separation by the anode-side gas-liquid separator and the cathode-side gas-liquid separator, and gas-liquid separated. It is an object of the present invention to provide an electrolysis system characterized in that electrolysis is continued while circulating liquid or water through a circulation line to a circulation tank.

  In order to achieve the above object, according to a fifth solving means of the present invention, the electrolytic cell comprises an alkaline water electrolytic cell using an alkaline aqueous solution as an electrolytic solution, and the electrolytic solution comprising the alkaline aqueous solution is supplied to the circulation tank. The generated gas that has been gas-liquid separated by the anode-side gas-liquid separation device and the cathode-side gas-liquid separation device is discharged from a gas discharge line, and the gas-liquid separated electrolyte is discharged from the anode chamber and the cathode chamber of the electrolytic cell. While continuing electrolysis while circulating in both electrolysis chambers, supplying pure water into the supply tank, supplying pure water corresponding to the amount of water lost by electrolysis from the supply tank to the circulation tank, It is an object of the present invention to provide an electrolytic system characterized in that electrolysis is continued while maintaining the alkali concentration of the electrolytic solution at an initial concentration.

  According to a sixth solving means of the present invention, in order to achieve the above object, the electrolytic cell comprises a salt electrolytic cell using a saline solution as an electrolytic solution, and the circulation tank comprises an anolyte circulation tank and a catholyte circulation tank. The supply manifold is made up of an anolyte supply manifold and a catholyte supply manifold, the discharge manifold is made up of an anolyte discharge manifold and a catholyte discharge manifold, and an electrolyte solution consisting of saline is supplied to the supply tank, and the supply An electrolytic solution made of a saline solution supplied to the tank is supplied into the anolyte circulation tank, and an anolyte solution made of the saline solution is supplied from the anolyte supply manifold to each anode chamber of the electrolysis unit via a supply tube. Water and cathode products supplied to the lower part and stored in the catholyte circulation tank are supplied from the catholyte supply manifold. The anolyte and product gas in each anode chamber are supplied from the upper part of each anode chamber to the lower part of each cathode chamber of the electrolysis unit via a tube, and from the anolyte discharge manifold through a discharge tube. Overflowing and discharging, the catholyte and product gas inside each cathode chamber are discharged from the catholyte discharge manifold from the top of each cathode chamber, and the anode-side gas-liquid separator and cathode-side gas-liquid separator The product gas separated by gas-liquid is discharged from a gas discharge line, and the anolyte separated by the anode-side gas-liquid separation device is circulated to the anolyte circulation tank by an anolyte circulation line, and the cathode-side gas-liquid separation The catholyte separated by the apparatus is circulated to the catholyte circulation tank by a catholyte circulation line, and all the anolyte and cathode in the electrolytic cell when the electrolysis operation is stopped or terminated The by its own weight, respectively to provide an electrolysis system and recovering the anolyte tank and catholyte circulating tank.

  In order to achieve the above object, the seventh solving means of the present invention connects an anode-side water sealing device to the anode-side gas-liquid separation device, and a cathode-side water-sealing device to the cathode-side gas-liquid separation device. Connecting, adjusting the pressure in the anode chamber and the pressure in the cathode chamber by adjusting the height of the water surface of the anode-side water sealing device and the height of the water surface of the cathode-side water sealing device, An electrolysis system in which the ratio of the product gas generated in the anode chamber mixed into the product gas generated in the cathode chamber and / or the ratio of the product gas generated in the cathode chamber mixed into the product gas generated in the anode chamber is controlled. It is to provide.

  The eighth solution in the present invention is to provide an electrolysis system in which the diaphragm is a neutral diaphragm in order to achieve the above object.

  A ninth solution of the present invention is to provide an electrolysis system in which the diaphragm is a cation exchange membrane in order to achieve the above object.

  In order to achieve the above object, a tenth solving means of the present invention uses the electrolysis system, supplies the electrolytic solution and / or pure water from the supply tank into the circulation tank, and supplies the electrolyte in the circulation tank. Electrolyte and / or pure water is supplied from the supply manifold through the supply tube to the inside of the electrolytic cell through the supply nozzle provided at the bottom of the electrolytic cell, and the electrolytic solution and / or pure water in the electrolytic cell is supplied. Overflow from the discharge nozzle provided in the upper part of the electrolytic cell is discharged to the discharge manifold through the discharge tube, and the electrolyte and product gas in the discharge manifold are discharged to the anode-side gas-liquid separator and the cathode. A gas-liquid separation is performed by the side gas-liquid separator into the electrolyte and / or water and the product gas, and the product gas that has been gas-liquid separated is discharged from a gas discharge line. While generating hydrogen gas, electrolysis is continued while circulating the electrolytic solution and / or pure water separated into gas and liquid to the circulation tank through the circulation line, and all the electrolysis in the electrolytic cell is stopped or terminated when the electrolysis operation is stopped. An object of the present invention is to provide an electrolysis method in which the liquid is recovered by its own weight from the supply nozzle into the circulation tank through the supply tube and the manifold.

According to the present invention, when the operation of the electrolytic cell used in the electrolysis system is stopped, it is possible to eliminate as much as possible a liquid pool at the bottom of the electrolytic cell, and by spontaneous discharge, the electrolytic solution, electrolytic product, water in the electrolytic cell Process design that can discharge all of the above, prevents corrosion of electrodes and electrolytic cells, has a compact structure, and can be installed in a narrow space in both normal and disaster situations In addition to being able to obtain a transportable and movable electrolysis system that can be easily transported and moved, hydrogen can be efficiently produced in a narrow space.
Further, according to the present invention, when the anode gas and the cathode gas are separated by a gas-liquid separator and then each gas is sealed with water, the gas pressure on the cathode side is higher than the gas pressure on the anode side or This is a process that can control the ratio of oxygen gas generated in the anode chamber to the cathode chamber by lowering it. Therefore, according to the present invention, the mixing ratio of oxygen gas and hydrogen gas is controlled, the electrolysis process is controlled within the explosion limit, the risk of explosion is reduced, and high purity hydrogen gas and high purity oxygen gas are reduced. It can be manufactured.

The front view which shows an example of the arrangement | positioning figure of the electrolytic cell and circulation tank which are used for the conventional electrolysis system. The front view which shows another example of the arrangement | positioning figure of the electrolytic cell and circulation tank which are used for the conventional electrolysis system. The front view which shows an example of the arrangement | positioning figure of the electrolytic cell and circulation tank which are used for the electrolysis system by this invention. The flowchart which shows an example at the time of using an alkaline-water electrolysis tank as an electrolysis tank used for the electrolysis system by this invention. The flowchart which shows an example at the time of using a salt electrolyzer as an electrolyzer used for the electrolysis system by this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 3, an electrolysis system that electrolyzes water to generate hydrogen and oxygen has an electrolytic solution 5 or an electrolytic cell 5 through a supply manifold 3 and a supply tube 4 from a circulation tank 1 by a pump 2. The electrolytic solution is discharged from the discharge tube 6 and the discharge manifold 7, and electrolysis is continued while circulating in the circulation tank 1. (The electrolyte supply / discharge process is exactly the same on the anode side and cathode side. Therefore, in the drawing, the process on one side is shown and described as a representative)
When the electrolysis is finished or the operation of the electrolytic cell 5 is stopped, all the electrolytic solution in the electrolytic cell 5 is put into the circulation tank 1 except when the restart is scheduled in a short period of time or when the electrolytic solution is circulated and stands by. Collected.
When the inventor ends the electrolysis or stops the operation of the electrolyzer 5, when all the electrolyte in the electrolyzer 5 is collected in the circulation tank 1, all the electrolyte in the electrolyzer is easily and naturally removed. As a result of studying a method that can be discharged into the circulation tank 1 by means of only the flow down, it has been found that the following two points are the most important requirements.
(1) An electrolytic tank 5 is provided in the upper stage of the electrolysis system, a circulation tank 1 is provided in the lower stage of the electrolysis system to supply and circulate the electrolytic solution to the electrolytic tank 5, and the circulation tank 1 is used as an electrolyte recovery tank. .
(2) The supply manifold 3 for supplying the electrolytic solution from the circulation tank 1 to the electrolytic cell 5 is installed so as to be positioned below the bottom surface of the electrolytic cell 5, and the supply manifold 3 is used as a manifold for collecting the electrolytic solution.

FIG. 1 is a front view showing an example of an arrangement diagram of an electrolytic cell 5 and a circulation tank 1 used in a conventional electrolysis system, where the circulation tank 1 and the electrolytic cell 5 are installed at the same height, and a supply manifold 3 Is provided in the middle stage of the electrolytic cell 5, and the discharge manifold 7 is provided on the upper part of the electrolytic cell 5. When the electrolytic cell 5 is stopped and the electrolytic solution in the electrolytic cell 5 is recovered, the electrolytic cell The electrolytic solution in the electrolytic cell 5 is collected in the circulation tank 1 by using a pump from a supply manifold 3 provided in the middle stage of 5.
However, in the method shown in FIG. 1, the electrolytic cell 5 is not only provided at the same height as the circulation tank 1, but the supply manifold 3 used for collecting the electrolytic solution is installed in the middle stage of the electrolytic cell 5. Therefore, when recovering the electrolytic solution in the electrolytic cell 5, it cannot be recovered depending on the natural flow, and it is necessary to use a pump, and even if a pump is used, the electrolytic solution accumulated at the bottom of the electrolytic cell It was impossible to recover everything.
In addition, since the circulation tank 1 and the electrolytic cell 5 are provided side by side in the same plane, the installation area becomes large, and it is difficult to store in a limited space such as a container, and it is difficult to move.

  FIG. 2 is a front view showing another example of the layout of the electrolytic cell 5 and the circulation tank 1 used in the conventional electrolysis system, and the supply manifold 3 used together with the recovery of the electrolytic solution is disposed on the bottom surface of the electrolytic cell 5. Although installed below, the electrolytic tank 5 and the circulation tank 1 are provided at the same height, so the electrolytic solution cannot be recovered by natural flow, and the pump is operated to discharge the electrolytic solution. Although necessary, it is impossible to prevent a part of the electrolytic solution in the electrolytic cell 5 from remaining at the bottom of the electrolytic cell 5, and there are problems similar to the arrangement of FIG.

FIG. 3 shows an example of the electrolysis system according to the present invention, and shows an example of the layout of the electrolytic cell 5, the circulation tank 1, the supply manifold 3, and the discharge manifold 7. As shown in FIG. According to the electrolysis system shown in FIG.
(1) The electrolytic tank 5 is provided at the upper stage of the electrolytic system, and the lower tank of the electrolytic system is provided with a circulation tank 1 that supplies and circulates the electrolytic solution to the electrolytic tank 5, and the circulation tank 1 is used for collecting the electrolytic solution. As well as being used as a tank,
(2) The supply manifold 3 for supplying the electrolytic solution from the circulation tank 1 to the electrolytic cell 5 is installed so as to be positioned below the bottom surface of the electrolytic cell 5, and the supply manifold 3 is used as a manifold for collecting the electrolytic solution. It is a process design.
Therefore, according to the electrolysis system according to the present invention shown in FIG. 3, when the electrolysis is finished or the operation of the electrolyzer 5 is stopped, all the electrolytic solution in the electrolyzer 5 is caused by its own weight without using a pump. It can be easily collected in the circulation tank 1.

  As an electrolytic cell used for an electrolysis system, there are an alkaline water electrolytic cell, a salt electrolytic cell, a water electrolytic cell, etc., in an alkaline water electrolytic cell, a high-concentration alkaline aqueous solution is used as an electrolytic solution, High-concentration saline is used, and pure water is used in the water electrolysis tank.

Further, an anode and a cathode are accommodated in the electrolytic cell, and these anode and cathode are provided with an active coating in order to improve their performance. This active coating generally employs a noble metal such as platinum, ruthenium, iridium, palladium, silver, etc., unlike the metal of the anode and / or cathode base material (titanium, nickel, iron, etc.).
If the process is such that the electrolytic solution is not completely discharged from the electrolytic cell, a small amount of the electrolytic solution accumulates at the lower part of the electrolytic cell and causes an electrochemical local cell reaction (galvanic cell reaction) at that location. For example, the electrochemical potential of 300 mV to 400 mV differs between nickel and platinum, and the difference becomes the driving force for corrosion.
On the other hand, the corrosion rate is greatly affected by the state of the electrolyte (temperature, pH, concentration, etc.). In any case, if a portion that is immersed in the electrolytic solution is generated, a corrosion phenomenon occurs.
Therefore, when all of the electrolytic solution in the electrolytic cell 5 is discharged to the circulation tank 1, if the electrolytic solution remains at the bottom of the electrolytic cell 5, the pure water, the high-concentration alkaline aqueous solution, the high-concentration saline, or the oxidizing agent There is a possibility that the electrolytic solution made of water in which the substance is dissolved corrodes the anode, cathode and other parts in the electrolytic cell, and the constituent material of the electrolytic chamber constituting the electrolytic cell.

However, according to the electrolysis system according to the present invention, when the electrolysis is finished or the operation of the electrolyzer 5 is stopped, all the electrolytic solution in the electrolyzer 5 is collected in the circulation tank 1 and the bottom of the electrolyzer 5 is electrolyzed. Since no liquid remains, it is possible to prevent corrosion of the anode, the cathode base material, the material of the electrolytic cell 5 and the like housed in the electrolytic cell 5.
Furthermore, according to the present invention, the electrolysis system has a compact structure, and can be installed in a narrow space and can be easily transported and moved in both cases during normal times and disasters. A possible electrolysis system can be obtained.

  As an electrolytic cell used in the electrolysis system of the present invention, an alkaline water electrolytic cell, an SPE type water electrolytic cell, a salt electrolytic cell, or the like can be used. First, the case where an alkaline water electrolytic cell is used as the electrolytic cell used in the electrolytic system of the present invention will be described.

FIG. 4 is a flowchart showing one embodiment of an electrolysis process in the case of using an alkaline water electrolytic cell 10 as an electrolytic cell used in the electrolytic system of the present invention.
In FIG. 4, 10 is an alkaline water electrolytic cell. This alkaline water electrolytic cell 10 includes an anode chamber 11 for accommodating an anode, a cathode chamber 12 for accommodating a cathode, the anode chamber 11 and the cathode chamber 12. It is comprised from the diaphragm 13 which partitions off. 1 is a circulation tank, 15 is a supply pump, 16 is a supply tank for supplying pure water 17 to the circulation tank 1, and pure water in the supply tank 16 is supplied to the circulation tank 1 by the supply pump 15. Supplied. The circulation tank 1 is supplied with an electrolytic solution 22 made of a high-concentration alkaline aqueous solution. The electrolytic solution 22 is supplied from the circulation tank 1 to the electrolytic cell 10 through a circulation line 24, and pure water 17 is also supplied to the circulation tank 1. And continuous electrolysis is performed while maintaining a desired alkali concentration.
The electrolytic solution 22 and the pure water 17 in the circulation tank 1 are supplied to the anode chamber 11 of the alkaline water electrolysis tank 10 by the circulation line 24 through the circulation pump 18a and the heat exchanger 19a, and the circulation pump 18b, It is supplied to the cathode chamber 12 of the alkaline water electrolytic cell 10 by the circulation line 24 through the exchanger 18b.
The electrolytic solution 22 is electrolyzed in the anode chamber 11 and the cathode chamber 12, and the electrolytic solution is electrolytically concentrated to generate an electrolytic concentrated solution. In the anode chamber 11, oxygen gas is generated, and the gas-liquid separation device The generated oxygen gas and the electrolytic solution are separated into gas and liquid by 20a, and the separated electrolytic solution is circulated to the circulation tank 1 by the circulation line 24. The oxygen gas separated by the anode-side gas-liquid separator 20a is exhausted through the anode-side water sealing device 21a.
At the same time, in the cathode chamber 12, hydrogen gas is generated and gas-liquid is separated into the generated hydrogen gas and electrolyte by the cathode-side gas-liquid separator 20 b, and the separated electrolyte is It is circulated in the circulation tank 1. The hydrogen gas that has been gas-liquid separated by the cathode-side gas-liquid separation device 20b is exhausted by the gas discharge line 23 through the cathode-side water sealing device 21b. In addition, in order to control the alkali concentration in both the electrolytic chambers and to continue the electrolysis while keeping the electrolysis conditions constant, pure water 17 corresponding to the water lost by electrolysis is supplied from the supply tank 16 to the circulation tank 1. Is done.
By continuously supplying pure water corresponding to the amount of water that disappears by electrolysis, it is possible to maintain an initially adjusted alkaline concentration electrolytic solution.

(Conditions for alkaline water electrolysis)
In the alkaline water electrolysis in the present invention, a high concentration alkaline water electrolytic solution having a predetermined alkali concentration is used as the electrolytic solution, and the electrolytic solution is preferably a caustic alkali such as caustic potash or caustic soda. 1.5-40 mass% is preferable. In particular, in view of suppressing power consumption, 15 to 40% by mass, which is a region with high electrical conductivity, is preferable. However, when considering the cost, corrosivity, viscosity, and operability related to electrolysis, the content is more preferably 20 to 30% by mass.

(Water seal system)
Furthermore, in the present invention, the electrolytic solution from which the generated gas has been separated by the gas-liquid separation devices 20a and 20b is circulated and supplied to both electrolytic chambers of the anode chamber 11 and the cathode chamber 12, thereby While controlling the alkali concentration in both electrolytic chambers, a considerable amount of water lost by electrolysis is made pure water 17 from the supply tank 16 via the circulation tank 1 to both the anode chamber 11 and the cathode chamber 12. Supplying to an electrolysis chamber, continuing electrolysis, maintaining constant electrolysis conditions, and concentrating the heavy water in the said raw material water.
In order to control the concentration to be constant, it is necessary to supply the circulation tank 1 with a considerable amount of pure water 17 that is continuously consumed.
On the other hand, the alkali concentration is allowed to stand, and the concentration gradually becomes higher, and is maintained up to the limit of 40% by mass of the alkaline water electrolysis concentration, and the volume reduction of the electrolytic solution can be confirmed. Moreover, it is also possible to start supplying raw water and maintain a final concentration of 40% by mass with respect to such a state.
In any case, in the circulation system proposed by the present invention, any of the methods can be operated and is flexible.
Furthermore, in the present invention, the pressure in the cathode chamber 12 and the anode chamber 11 are adjusted by adjusting the height of the water surface of the cathode-side water sealing device 21b and the height of the water surface of the anode-side water sealing device 21a. The ratio of the oxygen gas generated in the anode chamber 11 to the hydrogen gas generated in the cathode chamber 12 is controlled by adjusting the pressure in the chamber.
After the anode gas (oxygen gas) and the cathode gas (hydrogen gas) are separated by the anode-side gas-liquid separator 20a and the cathode-side gas-liquid separator 20b, the respective gases are separated into the anode-side water seal device 21a and the cathode-side water seal. When exhausting after water sealing with the device 21b, if the height of the water surface of the cathode side water sealing device 21b is made higher than the height of the water surface of the anode side water sealing device 21a, the gas pressure on the cathode side will be higher than the gas pressure on the anode side. As a result, the shift of oxygen gas generated in the anode chamber 11 to the cathode chamber 12 can be reduced, and the purity of the hydrogen gas can be improved. On the other hand, when it is desired to improve the purity of oxygen gas, if the height of the water surface of the anode-side water sealing device 21a is made higher than the height of the water surface of the cathode-side water sealing device 21b, the gas pressure on the anode side becomes the cathode side. The gas pressure becomes higher than the above gas pressure, so that the transition of the hydrogen gas generated in the cathode chamber 12 to the anode chamber 11 can be reduced, and the purity of the oxygen gas can be improved.

(Alkaline water electrolyzer)
As the alkaline water electrolytic cell 10, an electrolytic cell in which a two-chamber electrolysis unit provided with an anode chamber 11 storing an anode on both sides of a diaphragm 13 and a cathode chamber 12 storing a cathode is arranged on a multi-stage stack is used. As the anode and the cathode, use a zero gap type electrolytic cell in close contact with the diaphragm 13, a phinite type electrolytic cell provided slightly away from the diaphragm 13, or a separated electrolytic cell provided apart from the diaphragm 13. Can do. For depending on driving electric tightly but which does not damage the well layer diaphragm 13 for positional variations or amplitude preventing film during operation, the anode chamber, it is preferable to apply the operating differential pressure of the cathode chamber, 50~500mmH ₂ O of A differential pressure can be provided, and this differential pressure further controls the ratio of the generated gas (oxygen gas) generated in the anode chamber 11 to the generated gas (hydrogen gas) generated in the cathode chamber 12. be able to.
When a neutral diaphragm is used as the diaphragm 13, the pore diameter of the diaphragm to be used is reduced or a diaphragm whose surface is specially processed is used to move to the cathode chamber of generated gas (oxygen gas) generated in the anode chamber. It is also possible to reduce the shift of the generated gas (hydrogen gas) generated in the cathode chamber to the anode chamber.

(diaphragm)
As the diaphragm 13, a neutral diaphragm, a fluorine type or hydrocarbon type cation exchange membrane for salt electrolysis, and a cation exchange membrane for a fuel cell can be used. When a cation exchange membrane is used, when the oxygen concentration in hydrogen is 0.07%, the hydrogen concentration in oxygen is about 0.13%.
On the other hand, when a specially processed neutral diaphragm is used as the diaphragm 13, when the oxygen concentration in hydrogen is 0.06 to 0.09%, the hydrogen concentration in oxygen is 0.05 to 0.08%. Become.

(Anode and cathode)
As the anode and cathode, it is necessary to select a material that can withstand alkaline water electrolysis and has a small anode overvoltage and cathode overvoltage. Conventionally, the anode is iron or iron plated with Ni. As the cathode, a Ni substrate as it is or a Ni substrate coated with an active cathode is used. Also here, a nickel expanded mesh, a porous nickel expanded mesh for both the anode and the cathode, a metal electrode having a noble metal or its oxide coating on the surface of a base made of iron, and the like can be used.
Next, the case where an SPE type water electrolyzer is used as an electrolyzer used in the electrolysis system of the present invention will be described.

In the SPE type water electrolysis tank, an SPE type water electrolysis tank is used instead of the alkaline water electrolysis tank 10 in the electrolysis system using the alkaline water electrolysis tank shown in FIG. In the SPE type water electrolyzer, a cation exchange membrane is used as SPE, and on both sides thereof, an anode catalyst layer and a cathode catalyst layer are provided to form a membrane electrode assembly, and the membrane electrode assembly On both sides, a power supply is provided to constitute a unit cell.
In the electrolysis using the SPE type water electrolyzer in the present invention, pure water is supplied to the circulation tank 1 from the supply tank 16, and the pure water in the circulation tank 1 is supplied to the anode chamber 11 and the cathode catalyst on the anode catalyst layer side. Electrolysis is continued in the same manner as in the electrolysis system supplied from the circulation tank 1 to the cathode chamber 12 on the layer side and using an alkaline water electrolysis tank. In electrolysis using an SPE type water electrolyzer, pure water is used instead of an alkaline aqueous solution, and no electrolyte is used.
The electrolytic solution 22 is electrolyzed in the anode chamber 11 and the cathode chamber 12, oxygen gas is generated in the anode chamber 11, and gas-liquid separation is performed between the generated oxygen gas and the electrolytic solution by the gas-liquid separator 20a. The separated electrolyte is circulated to the circulation tank 1 through the circulation line 24. The oxygen gas separated by the anode-side gas-liquid separator 20a is exhausted through the anode-side water sealing device 21a.
At the same time, in the cathode chamber 12, hydrogen gas is generated and gas-liquid is separated into the generated hydrogen gas and electrolyte by the cathode-side gas-liquid separator 20 b, and the separated electrolyte is It is circulated in the circulation tank 1. The hydrogen gas that has been gas-liquid separated by the cathode-side gas-liquid separation device 20b is exhausted by the gas discharge line 23 through the cathode-side water sealing device 21b.
In addition, it is preferable to apply an operation differential pressure between the anode chamber and the cathode chamber, and a differential pressure of 50 to 500 mmH ₂ O can be provided, and the generated gas (oxygen gas) further generated in the anode chamber 11 by this differential pressure. ) Can be mixed with the product gas (hydrogen gas) generated in the cathode chamber 12.

  Next, the case where a salt electrolytic cell and other halide electrolytic cells are used as the electrolytic cell used in the electrolytic system of the present invention will be described.

In the case of using the salt electrolytic cell in the present invention, the ion exchange membrane type salt electrolytic cell shown in FIG. 5 is used. In the electrolysis system using the ion exchange membrane type salt electrolyzer 25, the circulation tank 1 includes an anolyte circulation tank 1a and a catholyte circulation tank 1b, and the supply tank 16 includes an anolyte supply tank 16a and pure water. The supply manifold 16 is composed of an anolyte supply manifold and a catholyte supply manifold, and the discharge manifold 7 is composed of an anolyte discharge manifold and a catholyte discharge manifold.
The electrolyte solution 26 made of saline is supplied to the anolyte supply tank 16a, and the electrolyte solution 26 made of salt solution supplied to the anolyte supply tank 16a is supplied into the anolyte circulation tank 1a. An anolyte 26 is supplied from the anolyte supply manifold to the lower part of each anode chamber 11 of the electrolysis unit via the supply tube 4.
On the other hand, the pure water 17 is supplied to the pure water supply tank 16b, and the pure water 17 and the catholyte supplied to the pure water supply tank 16b are supplied into the positive catholyte circulation tank 1b and supplied from the catholyte supply manifold. It is supplied to the lower part of each cathode chamber 12 of the electrolysis unit via a tube 4.
From the upper part of each anode chamber 11, the anolyte in each anode chamber 11 and the chlorine gas that is the generated gas are discharged from the anolyte discharge manifold through the discharge tube 6 and discharged. The catholyte in each cathode chamber 12 and the hydrogen gas that is the product gas are discharged from the catholyte discharge manifold from above the anolyte, and the anolyte separated by the anode-side gas-liquid separator 20a is circulated by a circulation line 24. The catholyte circulated to the anolyte circulation tank 1a and separated by the cathode-side gas-liquid separator 20b is circulated to the catholyte circulation tank 1b by a circulation line 24, and the electrolysis tank is closed or stopped when the electrolysis operation is stopped. All the anolyte and catholyte are collected in the anolyte circulation tank 1a and the catholyte circulation tank 1b by their own weight.
In addition, it is preferable to apply an operating differential pressure between the anode chamber and the cathode chamber, and a differential pressure of 50 to 500 mmH ₂ O can be provided, and the generated gas (chlorine gas) further generated in the anode chamber 11 by this differential pressure. ) Can be mixed with the product gas (hydrogen gas) generated in the cathode chamber 12.
In addition, the same electrolysis system can be performed even if it uses the halide electrolytic cell using halides, such as a fluorine, a bromine, and an element, instead of the salt of a salt electrolytic cell.

  In the electrolysis system according to the present invention, the electrolyzer 25, the circulation tanks 1 (a, b), the supply tanks 16 (a, b), driving devices such as the pump 15, the supply manifold 4, the discharge manifold 7 are provided. The anode side gas / liquid separator 20a and the cathode side gas / liquid separator 20b, the gas discharge line 23 and the circulation line 24 are all housed in a predetermined space.

  As the defined space, a container, a package unit or a skid mount, a truck loading unit, a transport container, a stationary space-saving system, or the like is used.

  Next, examples of the present invention will be described, but the present invention is not limited thereto.

<Example 1>
As shown in FIG. 3, an electrolytic cell 5 (electrolytic cell consisting of 10 elements) measuring 1.5 m in length, 1.0 m in width, and 1.7 m in height is 2 m in length, 6 m in width, and 2 m in height. In order to supply and circulate the electrolytic solution to the electrolytic cell 5 in the upper container provided in the container (not shown), the size is 1.3 m in length × 1.3 m in width × 1.2 m in height A circulation tank 1 was provided, and the circulation tank 1 was used in combination as a tank for collecting the electrolyte. Further, a supply manifold 3 for supplying the electrolytic solution from the circulation tank 1 to the electrolytic cell 5 was installed 20 mm below the bottom surface of the electrolytic cell 5, and the supply manifold 3 was also used as a manifold for collecting the electrolytic solution.
As the electrolytic cell, an alkaline water electrolytic cell shown in FIG. 4 was used.
The test was conducted in an electrolytic cell having an electrolysis area of 96 dm ² . Both the anode chamber (capacity 18L × 10) and the cathode chamber (capacity 18L × 10) are made of Ni, the anode is an expanded mesh, and the active anode coating is applied to (thickness 0.8 × SW3.7 × LW8.0). . The cathode is a fine mesh (thickness 0.15 × SW2.0 × LW1.0) and is coated with a noble metal-based active cathode coating.
As the diaphragm, a polypropylene-based 100 μm film subjected to hydrophilic treatment is used, which is sandwiched between both electrodes and assembled in a zero gap state.
The test process is as shown in FIG. 4, but the electrolysis temperature is controlled by a heater installed at the bottom of the electrolysis cell. The electrolytic solution is circulated from a circulation tank 1 (electrolyte capacity 2.5 L) installed in the lower part of the alkaline water electrolytic cell 10 with a flow rate of 3 to the anode chamber 11 and the cathode chamber 12 by circulation pumps 18a and 18b. It is supplied from the electrolyte supply nozzle at a rate of .9 L / min to 5.8 L / min. Each gas-liquid fluid discharged from the nozzle at the top of the electrolytic cell 10 is returned to the circulation tank 1 through the gas-liquid separators 20a and 20b, and the gas body is discharged out of the system. As operating conditions, 40 A / dm ² , 10 mass% KOH, electrolysis temperature, 75 to 85 ° C. The pressure in the cell system is determined by sealing the oxygen gas and hydrogen gas discharged from the anode chamber and the cathode chamber, respectively. In order to prevent diaphragm vibration during operation, the differential pressure between the anode chamber and the cathode chamber was maintained at 50 to 100 mmH ₂ O.
On the other hand, the liquid height of each water seal system can be controlled depending on whether the hydrogen gas purity or oxygen gas purity to be produced is expected, but in this embodiment, the purpose is to increase the hydrogen purity. The pressure difference was 50 mmH ₂ O under the condition of cathode pressurization.
Purified water was continuously supplied to the circulation tank with a considerable amount of raw water decomposed by water.
Operates for 6 hours every day for 5 days, supplying electrolyte from the circulation tank to the electrolytic cell every morning, starts operation, stops operation at night, drains the electrolyte, and collects it in the circulation tank. Drove.
Even in such an operation, the initially prepared alkali (here, caustic potash KOH) is not consumed and operation at a desired concentration can be performed, and continuous operation is possible by adding water decomposed by electrolysis to the system. It was. The alkali to be used is exactly the same even when caustic soda NaOH is used, and is not limited to caustic potash KOH.
When the electrolysis was terminated or the operation of the electrolytic cell 5 was stopped, the electrolytic solution in the electrolytic cell 5 naturally flowed down due to its own weight, and was all collected in the circulation tank 1 without using a pump or the like.
Moreover, since no electrolytic solution remains at the bottom of the electrolytic cell 5, corrosion of the anode, the cathode base material, the material of the electrolytic cell 5 and the like housed in the electrolytic cell 5 did not occur. Moreover, almost no pulsating phenomenon was observed.
Furthermore, this electrolysis system has a compact structure, and can be installed in a narrow space and can be easily transported and moved in both cases during normal times and during disasters.
The performance of the electrolytic cell when the operation was performed was as follows.
Test result: 1.82 V, hydrogen purity 99.92% 40 A / dm ²
Both gas purity and operating voltage were good.
As a result of using a salt electrolytic cell and a water electrolytic cell as the electrolytic cell 5 instead of the alkaline water electrolytic cell, the same results as above were obtained.

<Comparative Example 1>
The electrolytic tank shown in FIG. 4 is used, and as shown in FIG. 1, the circulation tank 1 and the electrolytic tank 5 are installed at the same height, the supply manifold 3 is provided in the middle stage of the electrolytic tank 5, and the discharge manifold 7 is provided in the electrolytic tank. 5 was provided at the top of the cell 5 for continuous electrolysis, the operation of the electrolytic cell was stopped, and the electrolytic solution in the electrolytic cell 5 was recovered.
As a result, not only the electrolytic tank 5 is provided at the same height as the circulation tank 1, but the supply manifold 3 used for collecting the electrolytic solution is installed in the middle stage of the electrolytic tank 5, so that the electrolytic tank When the electrolytic solution in 5 was recovered, it could not be recovered depending on natural flow.
Therefore, the discharge of the electrolyte was operated by operating the pump or sucking with the ejector, but still the electrolyte could not be completely discharged from the electrolytic cell, and the liquid could be accumulated at the bottom of the electrolytic cell, As a result, the active coating of the anode and cathode corroded and can no longer be used.

<Comparative example 2>
The electrolytic tank shown in FIG. 4 is used, and as shown in FIG. 2, the circulation tank 1 and the electrolytic tank 5 are installed at the same height, and the supply manifold 3 used together with the recovery of the electrolytic solution is provided from the bottom surface of the electrolytic tank 5. Electrolysis was carried out by installing it below.
As a result, since the electrolytic cell 5 and the circulation tank 1 are provided at the same height, the electrolytic solution cannot be collected by natural flow, and a part of the electrolytic solution in the electrolytic cell 5 is discharged even if it is discharged by a pump. Could not be prevented from remaining at the bottom of the electrolytic cell 5.

  The electrolysis system in the case of using the alkaline water electrolytic cell has been described above. However, the alkaline water can be used regardless of whether the SPE type water electrolytic cell is used or the salt electrolytic cell or other halogenated alkaline electrolytic cell is used. Similar results were obtained as when using an electrolytic cell.

  According to the present invention, when the operation of the electrolytic cell used in the electrolysis system is stopped, it is possible to eliminate as much as possible a liquid pool at the bottom of the electrolytic cell, and by spontaneous discharge, the electrolytic solution, electrolytic product, water in the electrolytic cell Process design that can discharge all of the above, prevents corrosion of electrodes and electrolytic cells, has a compact structure, and can be installed in a narrow space in both normal and disaster situations Therefore, it is possible to obtain a transportable and movable electrolysis system that can be easily transported and moved, and its wide use is expected.

1: circulation tank 1a: anolyte circulation tank 1b: catholyte circulation tank 2: pump 3: supply manifold 4: supply tube 5: electrolytic cell 6: discharge tube 7: discharge manifold 10: alkaline water electrolytic cell 11: anode chamber 12 : Cathode chamber 13: diaphragm 15: supply pump 16: supply tank 16 a: anolyte supply tank 16 b: pure water supply tank 17: pure water 18 a: circulation pump 18 b: circulation pump 19 a: heat exchanger 19 b: heat exchanger 20 a: Anode-side gas-liquid separator 20b: Cathode-side gas-liquid separator 21a: Anode-side water seal device 21b: Cathode-side water seal device 22: Electrolyte solution 23: Gas discharge line 24: Circulation line 25: Salt electrolytic cell 26: From salt Electrolyte

Claims (10)

An electrolytic solution and / or pure water comprising an aqueous solution by an electrolytic cell in which a plurality of electrolytic units each including an anode chamber containing an anode, a cathode chamber containing a cathode, and a diaphragm partitioning the anode chamber and the cathode chamber are stacked. In an electrolysis system that generates hydrogen gas from the cathode by electrolyzing
The electrolytic cell housed in the upper stage of the electrolysis system;
In order to circulate the electrolyte and / or pure water to the anode chamber and the cathode chamber, a circulation tank housed in the lower stage of the electrolysis system;
A driving device for circulating and driving the electrolyte and / or water;
A supply tank for supplying electrolyte and / or water into the circulation tank;
A supply manifold connected to the lower part of the electrolytic cell or below the electrolytic cell;
A supply nozzle provided at the bottom of the anode chamber and the cathode chamber of the electrolytic cell;
A supply tube connected between the supply nozzle and the supply manifold;
A discharge manifold connected to the top of the electrolytic cell;
A discharge nozzle provided above the anode chamber and the cathode chamber of the electrolytic cell;
A discharge tube connected between the discharge nozzle and the discharge manifold;
An anode-side gas-liquid separator and a cathode-side gas-liquid separator connected to the discharge manifold;
A gas discharge line for gas-liquid separation into the electrolyte and / or water and product gas by the anode-side gas-liquid separator and cathode-side gas-liquid separator, and for discharging the gas-liquid separated product gas;
A circulation line for circulating the electrolyte and / or water separated by the anode-side gas-liquid separator and the cathode-side gas-liquid separator to the circulation tank;
While generating hydrogen gas from the cathode and continuing the electrolysis while circulating the electrolytic solution and / or water separated into gas and liquid to the circulation tank by the circulation line, all the inside of the electrolytic cell at the time of stopping or terminating the electrolysis operation The electrolytic system is characterized in that the electrolytic solution and / or water are recovered by their own weight from the supply nozzle into the circulation tank through the supply tube and the supply manifold.   The electrolytic cell, the circulation tank, the supply tank, the drive device, the supply manifold, the discharge manifold, the anode side gas-liquid separation device and the cathode side gas-liquid separation device, the gas discharge line, and the circulation line are all The electrolysis system according to claim 1, wherein the electrolysis system is stored in a predetermined space.   The electrolysis system according to claim 2, wherein the defined space is at least one of a container, a package unit or a skid mount, a truck loading unit, a transport container, or a stationary space-saving system.   The electrolytic cell comprises an SPE type water electrolytic cell, pure water is supplied into the supply tank, the pure water is supplied to both the electrolytic chamber of the electrolytic chamber and the positive electrode chamber, The product gas that has been gas-liquid separated by the liquid separation device and the cathode-side gas-liquid separation device is discharged from a gas discharge line, and electrolysis is continued while the gas-liquid separated electrolyte or water is circulated to the circulation tank by the circulation line. The electrolysis system according to claim 1.   The electrolytic cell is composed of an alkaline water electrolytic cell using an alkaline aqueous solution as an electrolytic solution, the electrolytic solution comprising the alkaline aqueous solution is supplied to the circulation tank, and the gas-liquid is separated by the anode-side gas-liquid separator and the cathode-side gas-liquid separator. The separated generated gas is discharged from a gas discharge line, and electrolysis is continued while circulating the electrolytic solution separated into gas and liquid to both the anode chamber and the cathode chamber of the electrolytic tank, and in the supply tank. Supply pure water, supply pure water corresponding to the amount of water lost by electrolysis from the supply tank to the circulation tank, and continue electrolysis while maintaining the alkali concentration of the electrolyte at an initial concentration. The electrolysis system according to claim 1.   The electrolytic tank comprises a salt electrolytic tank using saline as an electrolyte, the circulation tank comprises an anolyte circulation tank and a catholyte circulation tank, the supply manifold comprises an anolyte supply manifold and a catholyte supply manifold, The discharge manifold is composed of an anolyte discharge manifold and a catholyte discharge manifold, supplying an electrolyte made of saline to the supply tank, and an electrolyte made of saline supplied to the supply tank into the anolyte circulation tank The supplied anolyte consisting of the saline is supplied to the lower part of each anode chamber of the electrolysis unit from the anolyte supply manifold via the supply tube, and stored in the catholyte circulation tank and the cathode generation The material is supplied from the catholyte supply manifold to the lower part of each cathode chamber of the electrolysis unit through a supply tube. The anolyte and the product gas inside each anode chamber are discharged from the top of each anode chamber by overflowing from the anolyte discharge manifold via a discharge tube, and each cathode is discharged from the top of each cathode chamber. The catholyte and the product gas inside the chamber are discharged from the catholyte discharge manifold, and the product gas separated by the anode-side gas-liquid separator and the cathode-side gas-liquid separator is discharged from a gas discharge line, The anolyte separated by the anolyte gas-liquid separator is circulated to the anolyte circulation tank by an anolyte circulation line, and the catholyte separated by the cathode-side gas-liquid separator is circulated by the catholyte circulation line. The anolyte circulation tank and the catholyte circulation tank are circulated to the circulation tank, and all the anolyte and catholyte in the electrolytic cell are caused by their own weight when the electrolysis operation is stopped or terminated. Electrolysis system according to claim 1, wherein the recovering in the click.   An anode-side water-sealing device is connected to the anode-side gas-liquid separation device, and a cathode-side water-sealing device is connected to the cathode-side gas-liquid separation device. The pressure inside the anode chamber and the pressure inside the cathode chamber are adjusted by adjusting the water surface height of the sealing device, and the generated gas generated in the anode chamber is mixed into the generated gas generated in the cathode chamber. The electrolysis system according to any one of claims 1, 2, 4 to 6, wherein the ratio of the generated gas and / or the ratio of the generated gas generated in the cathode chamber to the generated gas generated in the anode chamber is controlled.   The electrolysis system according to claim 1, wherein the diaphragm is a neutral diaphragm.   The electrolysis system according to claim 1, wherein the diaphragm is a cation exchange membrane.   The electrolytic system according to any one of claims 1 to 9, wherein the electrolytic solution and / or pure water is supplied from the supply tank into the circulation tank, and the electrolytic solution and / or pure water in the circulation tank is supplied. Is supplied from the supply manifold to the inside of the electrolytic cell through the supply tube and from the supply nozzle provided at the bottom of the electrolytic cell, and the electrolytic solution and / or pure water in the electrolytic cell is supplied to the upper part of the electrolytic cell. Overflow from the provided discharge nozzle and discharge to the discharge manifold through the discharge tube, and the electrolyte and product gas in the discharge manifold are discharged by the anode-side gas-liquid separator and the cathode-side gas-liquid separator. Gas-liquid separation into the electrolyte and / or water and product gas, and the gas-liquid separated product gas is discharged from a gas discharge line, and hydrogen gas is generated from the cathode. Electrolysis is continued while circulating the electrolytic solution and / or pure water separated into gas and liquid to the circulation tank by the circulation line, and all the electrolytic solution in the electrolytic cell is discharged from the supply nozzle when the electrolytic operation is stopped or finished. The electrolytic method is characterized in that it is recovered by its own weight in the circulation tank through the supply tube and the manifold.

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