KR-102962787-B1 - Hydrogen storage method, hydrogen gas production method and hydrogen gas production system

Abstract

The present invention relates to a method for producing hydrogen gas comprising: a first process of concentrating an aqueous solution containing an alkali metal salt of formate; a second process of producing formic acid by protonating at least a portion of the alkali metal salt of formate by electrodialysis; and a third process of producing hydrogen gas by decomposing the formic acid.

Inventors

• 마츠다 히로카즈
• 히라노 마코토

Assignees

• 닛토덴코 가부시키가이샤

Dates

Publication Date

20260508

Application Date

20201118

Priority Date

20191209

Claims (9)

1. A method for producing hydrogen gas using an alkali metal salt of formate as a hydrogen storage material, A first process comprising a process of concentrating an aqueous solution containing the above alkali metal salt formate using a separation membrane unit equipped with a reverse osmosis membrane, and A method for producing hydrogen gas, comprising a second process of producing formic acid by protonating at least a portion of the alkali metal salt of formate by electrodialysis, and a third process of producing hydrogen gas by decomposing the formic acid.
2. In Article 1, Additionally, a method for producing hydrogen gas comprising a process of generating the alkali metal salt formate in an aqueous solution using carbon dioxide in the presence of an alkali metal salt.
3. delete
4. In Article 1 or Article 2, A method for producing hydrogen gas, wherein the first process comprises a process of distilling and removing water from an aqueous solution containing the alkali metal salt of formate.
5. In Article 1 or Article 2, The above alkali metal salt formate is a method for producing hydrogen gas, which is sodium formate.
6. A hydrogen storage method comprising a process of generating an alkali metal salt formate in an aqueous solution using carbon dioxide in the presence of an alkali metal salt, and a first process of concentrating the aqueous solution containing the alkali metal salt formate.
7. In Article 6, The above first process is a hydrogen storage method, which is a process of obtaining a solid of the alkali metal salt of the formate by the above concentration.
8. As a hydrogen gas production system using alkali metal formate salts as hydrogen storage materials, A concentration device for concentrating an aqueous solution containing the above alkali metal salt formic acid, and A hydrogen gas production system comprising an electrodialysis device that produces formic acid by protonating at least a portion of the alkali metal salt of the formic acid by electrodialysis, and a formic acid decomposition device that produces hydrogen gas by decomposing the formic acid.
9. In Article 8, Additionally, a hydrogen gas production system comprising an alkali metal salt formate production apparatus that produces the alkali metal salt formate in an aqueous solution using carbon dioxide in the presence of an alkali metal salt.

Description

Hydrogen storage method, hydrogen gas production method and hydrogen gas production system The present invention relates to a hydrogen storage method, a method for producing hydrogen gas, and a hydrogen gas production system. High expectations are being placed on hydrogen energy as a next-generation energy source due to issues such as global warming and the depletion of fossil fuels. While realizing a hydrogen energy society requires technologies for hydrogen production, storage, and utilization, hydrogen storage presents various challenges regarding storage, transportation, safety, cycles, and costs. In addition, the development of various materials such as hydrogen storage alloys, organic hydrides, inorganic hydrides, organometallic complexes, and porous carbon materials is being considered as hydrogen storage materials. Organic hydrides are attracting attention due to their advantages of ease of handling, high hydrogen storage density, and lightweight nature. Since some organic hydrides are considered hazardous materials, they are sometimes used as low-concentration solutions. Additionally, when extracting hydrogen through a dehydrogenation reaction, it is necessary to separate and recover the hydrogen with high efficiency. Hydrocarbon compounds such as formic acid, benzene, toluene, biphenyl, naphthalene, cyclohexane, and methylcyclohexane are known as organic hydrides. Among them, formic acid is attracting attention as an excellent compound for hydrogen storage materials because it requires low energy for dehydrogenation reactions and is easy to handle. When formic acid is used as a hydrogen storage material, it is produced by contacting carbon dioxide with hydrogen in a basic solution or by electrochemically reducing carbon dioxide. However, the reaction stops upon reaching equilibrium, yielding only a low-concentration formic acid solution. To reduce transportation costs, it is necessary to obtain a high-concentration formic acid solution. Furthermore, it is necessary to separate and recover formic acid from the solution with high efficiency. Therefore, in Patent Document 1, for the purpose of producing formic acid by hydrogenation of carbon dioxide, producing hydrogen by dehydrogenation of formic acid, and storing and producing hydrogen with high efficiency and high energy efficiency, a method of producing formic acid or/and formate using a catalyst and producing hydrogen from formic acid or/and formate using a catalyst is investigated. FIG. 1 is a drawing for explaining a second process related to an embodiment of the present invention. FIG. 2 is a drawing for explaining an embodiment of the present invention. FIG. 3 is a drawing showing an example of a hydrogen gas production system related to an embodiment of the present invention. Hereinafter, embodiments of the present invention will be described in detail. A hydrogen gas production method related to an embodiment of the present invention is a method for producing hydrogen gas using an alkali metal salt of formate as a hydrogen storage material, comprising: a first process of concentrating an aqueous solution containing said alkali metal salt of formate; a second process of producing formic acid by protonating at least a portion of said alkali metal salt of formate by electrodialysis; and a third process of producing hydrogen gas by decomposing said formic acid. By the hydrogen gas production method related to the embodiment of the present invention, hydrogen can be stored in a state of excellent handling, concentrated in a simple manner, and hydrogen gas can be produced with high efficiency. [Process for Forming Alkali Metal Salts of Formic Acid] A hydrogen gas production method related to an embodiment of the present invention may also include a process of producing an alkali metal salt of formate in an aqueous solution using carbon dioxide in the presence of an alkali metal salt (a process for producing an alkali metal salt of formate). Hydrogen can be stored as an alkali metal salt formate through a process for producing an alkali metal salt formate. Alkali metal salt formate has the advantages of high hydrogen storage density, easy handling, and long-term storage because it is safe and stable as a chemical substance when used as a hydrogen storage material. An aqueous solution of the alkali metal salt formate produced by this process can be provided to the first process. The alkali metal salt related to the embodiments of the present invention may be an inorganic salt of an alkali metal. One type of alkali metal salt may be used alone or in combination. Examples of alkali metal ions constituting the cation portion of alkali metal salts include lithium, sodium, potassium, rubidium, and cesium ions. Among these alkali metal ions, sodium ions or potassium ions are preferred. The anionic part of the alkali metal salt is not particularly limited as long as it is capable of producing an alkali metal salt of formate. Examples of anionic parts inc