Method and apparatus for producing hydrogen

Abstract

A method for producing hydrogen wherein use is made of a high temperature steam electrolysis apparatus having an electrolysis vessel being partitioned into the anode side and the cathode side by the use of a solid oxide electrolyte film as a diaphragm, steam is fed to the above cathode side and a reducing gas is fed to the anode side, and steam electrolysis is carried out at a high temperature, characterized in that the reducing gas and the steam fed to the electrolysis vessel has a temperature of 200 to 500 DEG C. The above temperature range for the reducing gas and the steam fed to the electrolysis vessel has been found to be an optimum temperature range, as a result of taking the heat balance within the vessel into consideration, in a high temperature steam electrolysis apparatus wherein a solid oxide electrolyte film is used, a reducing gas is fed to the anode side and steam is fed to the cathode side, an oxygen ion is allowed to react with said reducing gas on the cathode side, to thereby generate a concentration gradient for an oxygen ion and thus reduce an electrolysis voltage.

Description

technical field [0001] The present invention relates to a method and an apparatus for producing high-purity hydrogen by electrolyzing high-temperature water vapor. Background technique [0002] The reducing gas mainly composed of hydrogen and carbon monoxide can be reformed with steam to hydrogenate the carbon monoxide, and then the hydrogen can be separated and refined, which can be effectively used in the chemical industry and as fuel for fuel cells. However, since platinum is used as a catalyst in the polymer electrolyte fuel cell expected as a technology close to practical use recently, the carbon monoxide contained in the hydrogen of the fuel must be almost zero. In order to obtain high-purity hydrogen gas reforming Purification is troublesome, and its operability and economical efficiency become problems. In addition, in the electrolysis method using electric power generated from pyrolysis gas, high-purity hydrogen can be obtained with a relatively simple structure, b...

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Problems solved by technology

However, even with this method, electricity must be used to supplement 60% or more of the decomposition energy of water

As an improvement method of this high-temperature steam electrolysis method, in U.S. Patent No. 6,051,125, a method of supplying natural gas to the anode of the electrolytic cell to reduce the electrolysis voltage required to move oxygen to the anode side is proposed, but this method not only consumes expensive The shortcomings of natural gas, and there must be countermeasures to prevent electrode pollution caused by carbon precipitated in the reaction of oxygen and natural gas, which is practically problematic

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