KR20090002910A - Process for producing hydrogen and oxygen gas separation membranes - Google Patents

Abstract

A manufacturing method of hydrogen/oxygen gas separating diaphragms of an electrolyzer is provided to ultimately maximize operating efficiency of the electrolyzer and separation efficiency of oxygen and hydrogen gases by removing factors deteriorating electrolysis efficiency or obstructing control of a water level. In gas separating diaphragms of an electrolyzer which are combined into a unit tank together with gaskets, electrodes, diaphragm fixing rings, and cell frames to obtain produced hydrogen and oxygen gases in the separated state by performing electrolysis with respect to an electrolyte supplied into the electrolyzer, a manufacturing method of hydrogen/oxygen gas separating diaphragms of the electrolyzer comprises the steps of: preparing a polypropylene yarn having a thickness of 0.5 mm or less, a specific gravity of 0.85 to 0.96 and a hardness of R85 to 110; primarily treating the surface of the polypropylene yarn with a sodium hydroxide(NaOH) solution; drying the primarily surface-treated polypropylene yarn coated with the electrolyte in an atmosphere of 190 deg.C or less for less than 90 seconds; and weaving the dried polypropylene yarn into mesh-like porous diaphragms in such a shape that warps and wefts of the diaphragms are the same as each other or not.

Description

Membrane of Water Electrolyger for Separating Hydrogen and Oxygen Gasses and Manufacturing Method}

1 is an enlarged cross-sectional view of a main part for explaining the electrolytic cell structure of the present invention,

Figure 2 is an enlarged perspective view for explaining the cell frame structure of the present invention

Figure 3 is an enlarged cross-sectional view showing an electrolytic cell fixing means of the present invention.

The present invention relates to a number of electrolysis tanks and a method for producing an oxygen gas separation membrane. In particular, a method of manufacturing a gas separation diaphragm of an electrolysis tank that maximizes ion flowability and thus improves electrolysis efficiency and obtains high quality hydrogen gas and oxygen gas in a separated state. will be.

Electrolysis causes a chemical change by passing a current through an ion conductor such as an aqueous electrolyte solution.

In other words, anions discharge from the surface of the higher electrode (anode) to generate various substances (for example, in electrolysis of an aqueous sodium chloride solution, chlorine molecules such as C1- → C1 + e, 2C1 → C12). It generates and generates gaseous chlorine, and some of it dissolves in water to cause various reactions. Zn → Zn2 + 2e, zinc is melted out.)

On the other hand, the discharging of the cation occurs on the surface of the lower electrode (cathode) with a lower potential (for example, in the electrolysis of sulfuric acid, hydrogen molecules are generated such as H + + e → H, 2H → H 2 and hydrogen, which is a gas). Also, metals are precipitated. (For example, when electrolytic copper sulfate solution is electrolytically deposited on the surface of the cathode, such as Cu2 + 2e → Cu.)

On the other hand, electrolysis is actually applied to a wide range of fields, and is used for electrolysis analysis, electrometallurgy, electrolysis polishing, electroplating, electrolysis condensers, and the production of chlorine and sodium hydroxide by electrolysis of saline.

In addition, hydrogen and oxygen can be obtained by electrolyzing water. The water electrolysis method occupies an important place as an industrial manufacturing method of obtaining hydrogen, and is a unit tank of water electrolyzer. It is common to have a structure in which several or more are combined. (See Figure 2)

In addition, referring to FIGS. 1 and 2, as the cathode, iron having a low hydrogen overvoltage and excellent corrosion resistance is mainly used, and an anode or an iron plate coated with nickel is mainly used as an electrolyte. Potassium hydroxide or sodium hydroxide solution with high electrical conductivity is used.

0.5V의 조전압(糟電壓) 또는 극간전압으로 조정된다.In order to prevent the mixing of the produced gas, a separation membrane such as asbestos cloth is placed between the anodes, and the purity of the gas is 99.5 to 99.7% of hydrogen and 99.0 to 99.5% or more of oxygen. Theoretical decomposition voltage is 1.125V when electrolyzed using potassium hydroxide or sodium hydroxide at the temperature of 60 ℃, but usually 2.0

The voltage is adjusted to 0.5V of regulated voltage or inter-pole voltage.

In the upper portion of the electrode plate, two gas discharge holes for passing hydrogen gas and oxygen gas are respectively formed.

In addition, a gasket, a diaphragm fixing ring, a cell frame, etc. form a unit group together with a diaphragm and an electrode plate to form a unit group, and a plurality of such unit groups are laminated and combined to fix the cathode and anode electrode terminals to form an electrolytic cell.

On the other hand, an oxygen gas flow hole and a hydrogen gas flow hole are formed in an upper portion of each of the diaphragms 120, and an electrolyte flow hole is formed in a lower portion thereof, and different polarities are charged between the anode electrode and the electrode. The planar diaphragm 120 having a smaller diameter than the electrode 140 is provided between the electrodes 140 and between the anode electrode and the cathode electrode.

Therefore, when the diaphragm 120 is closely attached to and fixed to one surface of the frame 110, each of the extension portions of the ring 130 is connected to the hole of the diaphragm 120 in a state in which the holes of the ring 130 and the diaphragm 120 communicate with each other. It is in close contact with the surface of the middle side, the diaphragm 120 is positioned between each electrode 140 of one unit set and the electrode of another unit set.

As such, the hydrogen gas (or oxygen gas) generated at one surface of the electrode 140 of one unit by the diaphragm 120 is mixed with the oxygen gas (or hydrogen gas) generated at the corresponding surface of the other unit electrode. Will not be.

At this time, the electrolyte flowing into the electrolyte flow hole from the outside of the diaphragm 120 through the cutout formed in the cutout portion of the cylindrical portion formed in the electrolyte flow hole hole edge of the cell frame 110 and the diaphragm fixing ring 130. Flows into the front space.

Electrolyte inflow and hydrogen, oxygen gas discharge process as described above is carried out between all the unit tank constituting the electrolytic cell, the electrolysis of the electrolyte is made in the space between the electrode and the electrode of each unit tank.

As the material of the cell frame 110, glass-reinforced fiber plastics, such as polysulfone, polyimide, polyphenylene sulfide, and polypropylene, which are excellent in chemical resistance and heat resistance and have high mechanical strength, which can be continuously used at a temperature of 90 ° C. The gasket 150 is suitable for ethylene-propylene copolymer (EPDM), polytetrafluoroethylene (Teflon), etc. having high chemical resistance and heat resistance and high mechanical strength as well as mechanical strength.

In addition, the diaphragm 120 is made of fiber using asbestos having a thickness of 0.5 to 3.0 mm, or asbestos fiber reinforced with asbestos, asbestos cloth, or Ni thread to secure heat resistance, electrical conductivity, ion flow resistance, and the like.

However, as described above, the gas separation diaphragm of the conventional electrolytic cell is characterized by heat resistance and electrical conductivity in an electrolytic cell employing 25% potassium hydroxide (KoH) as the electrolyte / electrolyte employing 30% sodium hydroxide (NaoH) as the electrolyte. Since this lowers the ion flow characteristics, and thus ultimately lowers the separation efficiency of oxygen and hydrogen gas, there is a need for a means to solve this problem.

The present invention has been invented to solve the conventional problems as described above, the purpose of which is due to the penetration of dyes and chemicals in the basic process of fiber processing to produce a diaphragm and generates a significant amount of bubbles in the electrolytic cell and maintain isostatic pressure It is possible to reduce the effective area of the electrode to reduce the efficiency, and to eliminate the factors that hinder the water level control due to the hydrophobic phenomenon, thereby ultimately maximizing the separation efficiency and operating efficiency of oxygen and hydrogen gas. Hydrogen, oxygen gas separation membrane to be prepared.

In order to achieve the above object, the present invention, in order to obtain a heterogeneous gas generated by the electrolysis of the electrolyte supplied into the separated state in a unit group together with the jacket, electrode, diaphragm fixing ring, cell frame In the method for producing a gas separation membrane of the water-receiving tank combined

The diaphragm is provided with a polypropylene yarn having a thickness of less than 0.5mm / hardness of R85 ~ 110; Primary surface treatment of the polypropylene yarn with sodium hydroxide (NaoH) solution; Drying the first surface-treated electrolyte coating polypropylene yarn for less than 90 seconds in an atmosphere of 190 ° C. or less; In the step of weaving the dried polypropylene yarn with a diaphragm so as to have a mesh form in the form including the warp yarns (threads constituting the longitudinal direction of the fiber) and the weft yarns (threads constituting the width direction of the fiber) is not the same. Is done.

The concentration of sodium hydroxide (NaoH) solution used for the primary surface treatment is 30-45%, and the concentration of potassium hydroxide (KoH) solution used for the secondary surface treatment is 25%.

Hereinafter, preferred embodiments of the present invention will be described in more detail.

According to the present invention, a gasket, an electrode, a diaphragm fixing ring, a cell frame, and the like constitute one unit group together with a diaphragm and an electrode plate.

Multiple stacks are combined and fixed by fixing the cathode and anode electrode terminals (see FIGS. 2 and 3).

The diaphragm 120 according to the present invention is obtained by weaving a polypropylene yarn having a thickness of 0.5 mm or less / 0.85 to 0.96, and a polypropylene yarn having a thickness of 0.5 mm or less / 0.85 to 0.96. It is a common polypropylene company distributed in the market.

The above polypropylene yarns are first surface treated with sodium hydroxide solution, and the first surface treated electrolyte coated polypropylene yarns are subjected to secondary surface treatment with potassium hydroxide solution, because of the lowered heat resistance and electrical conductivity. It is possible to prevent the deterioration and to prevent the ion flow characteristics from being deteriorated, thereby ultimately maximizing the separation efficiency of oxygen and hydrogen gas, and also using the sodium hydroxide solution and potassium hydroxide solution for primary and secondary If the surface treatment is not performed, it takes a lot of time until the initial saturation state of the electrolysis is activated in the electrolysis tank, and this causes difficulty in controlling the water level such as bubble generation and isostatic pressure. Therefore, it is preferable that the first surface treatment with sodium hydroxide solution and the second surface treatment with potassium hydroxide solution.

Meanwhile, since the sodium hydroxide is soluble in water, a large amount of sodium hydroxide attached to the polypropylene yarn by the primary coating is dissolved in the aqueous potassium hydroxide solution by preliminary coating in the aqueous potassium hydroxide solution without any further treatment after the primary coating. Although it can be removed from the surface of the propylene yarn, the secondary surface treatment is taken out immediately after soaking for a very short time (within 5 seconds), so that dissolution of sodium hydroxide hardly occurs.

In addition, when performing the said 1st and 2nd surface treatment, the temperature of each aqueous solution is made on the conditions of normal temperature which is the temperature of air | atmosphere. When the primary surface treatment is performed, the temperature of each aqueous solution is performed under the condition of normal temperature which is a temperature in the air. The reason why the concentration of the sodium hydroxide solution used for the primary surface treatment is 30 to 45% is preferable because it gives the most suitable surface treatment effect of the sodium hydroxide solution.

The reason why the concentration of the potassium hydroxide solution used for the second surface treatment is 25% is preferable because it gives the most suitable surface treatment effect of the potassium hydroxide solution.

As described above, after the first and second surface treatment steps of the polyflofilene company using the sodium hydroxide solution and the potassium hydroxide solution, the surface-treated polypropylene yarn is dried in an atmosphere of 190 ° C. or less for 90 seconds or less. Match density and increase form stability.

However, the step of drying the temperature in the atmosphere to the extent that the moisture is dried for less than 90 seconds in an atmosphere of 190 ℃ or less, even if a condition slightly higher than the thermal deformation temperature (104 ℃) of polypropylene, the thermal deformation of There is no worry.

When the above process is completed, the warp yarns (threads constituting the longitudinal direction of the fiber) and the weft yarns (fiber width direction) are finally made using an electrolyte-coated polypropylene yarn prepared to have a thickness of 0.5 mm or less / specific gravity of 0.85 to 0.96 or less. The yarn constituting the same) is manufactured by weaving into a diaphragm having pores of 60 mesh or more in the form including the same or not in thickness.

Embodiments of the present invention relate to a gas separation diaphragm of a water electrolytic bath combined with a gasket, an electrode, a diaphragm fixing ring, and a frame in a unit tank.

That is, as described above, in the electrolytic bath, a gasket, a ring for diaphragm processing, a snow frame, and the like form a unit group together with a diaphragm and an electrode plate. It is configured by fixing. (See Figures 1 and 2)

In addition, an oxygen gas flow hole and a hydrogen gas flow hole are respectively formed in an upper portion of each of the diaphragms 120, and an electrolyte flow hole is formed in a lower portion thereof. It is also the same as the conventional structure that the disk diaphragm 120 having a smaller diameter than the electrode 140 is provided between the electrodes 140 and between the positive electrode and the negative electrode.

On the other hand, the diaphragm is made of a polypropylene yarn having a thickness of 0.2 to 3.5 mm / specific gravity of 0.85 to 0.96 and a hardness of R85-110, and is woven in the primary and secondary surface treatment processes as described above. The polypropylene membrane is hydrolyzed by a continuous alkali treatment method with a sodium hydroxide (NaoH) solution having a concentration of 30-40% by weight to prepare a secondary surface treatment.

As described above, the gas separation diaphragm of the electrolysis tank and the manufacturing method thereof according to the present invention can prevent deterioration of heat resistance and electric conduction characteristics of the electrolytic bath, and also prevent the ion flow characteristic from deteriorating, This provides the advantage that it is possible to maximize the separation efficiency of oxygen and hydrogen gas.

Claims (4)

There is a gas separation diaphragm of an electrolysis tank, which is combined with a gasket, an electrode, a diaphragm fixing ring, and a cell frame in order to obtain the water and oxygen gas generated by performing electrolysis on the supplied electrolyte solution. Having a polypropylene yarn having a thickness of less than 0.5 mm / specific gravity of 0.85 to .96 and a hardness of R85 to 110; Primary surface treatment of the polypropylene yarn with sodium hydroxide (NaoH) solution; Drying the first surface-treated electrolyte coating polypropylene yarn for less than 90 seconds in an atmosphere of 190 ° C. or less; Weaving the dried polypropylene yarns into a diaphragm having pores on the mesh in the form of inclination (the yarn constituting the longitudinal direction of the fiber) and the weft yarn (the yarn constituting the width direction of the fiber) are the same or not. The number of electrolysis tanks, characterized in that the oxygen separation membrane manufacturing method The method of claim 1, wherein the concentration of the sodium hydroxide solution used for the primary surface treatment is 30 to 45%. The method of claim 1, wherein the concentration of the potassium hydroxide solution used for the secondary surface treatment is 25%. The method of claim 1, wherein the warp yarn (a yarn constituting the longitudinal direction of the fiber) and the weft yarn (which constitutes the width direction of the fiber) are made using an electrolyte-coated polypropylene yarn manufactured to have a thickness of 0.5 mm or less / specific gravity of 0.85 to 0.96. The number of electrolysis tanks and oxygen gas separation membrane manufacturing method, characterized in that for producing a diaphragm having pores of 60 mesh or more in the form including the same or not thickness.

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