Method of controlling hydrogen/oxygen producing system and hydrogen/oxygen producing system
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Solution Overview
Problem
The hydrogen/oxygen producing system with solid polymer type water electrolysis and electrochemical hydrogen pressurizing apparatus faces issues with gas crossover and membrane damage due to improper decompression during system shutdown, leading to potential hydrogen expansion and membrane breakage.
Innovation Solution
A method of controlling the system by performing first and second decompression processes to manage the decompression speeds of the electrochemical hydrogen pressurizing apparatus and water electrolysis apparatus, ensuring the pressurizing cathode decompression does not exceed a basic speed and maintaining the anode pressure higher than the cathode pressure to prevent crossover and membrane damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If rapid decompression is performed during system shutdown, then decompression time is reduced, but membrane damage and hydrogen expansion occur
Solution Approach 1:
The patent applies preliminary action by performing decompression in a controlled sequence before complete system shutdown. The electrochemical hydrogen pressurizing apparatus is decompressed first to a predetermined pressure, and only then is the water electrolysis apparatus decompressed. This preliminary staged decompression prevents sudden pressure drops that would cause membrane damage and hydrogen expansion, while still achieving relatively quick overall decompression.
2Productivity
If high pressure is applied to hydrogen gas during water electrolysis, then hydrogen production efficiency is improved, but gas crossover through the electrolyte membrane increases
Solution Approach 1:
The patent replaces the conventional mechanical compression system with an electrochemical hydrogen pressurizing apparatus that uses electrochemical reactions to generate and pressurize hydrogen gas. This electrochemical approach allows for more precise pressure control and reduces gas crossover compared to mechanical compression, while maintaining high hydrogen production efficiency. The electrochemical process inherently manages pressure differentials more effectively across the electrolyte membrane.
3Object-generated harmful factors
If oxygen gas is maintained at higher pressure than hydrogen gas, then gas mixing concentration is reduced, but additional pressurizing equipment is required
Solution Approach 1:
The patent merges the water electrolysis function with the hydrogen pressurizing function into a single integrated electrochemical system. The electrochemical hydrogen pressurizing apparatus performs both hydrogen generation and pressurization in one unit, eliminating the need for separate oxygen pressurizing equipment. This integration allows efficient pressure management to prevent gas mixing while reducing overall system complexity and equipment requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively prevents membrane damage and crossover, allowing for safe and controlled decompression of both apparatuses during system shutdown, maintaining gas purity and extending membrane durability.
Implementation Method 1
a water electrolysis apparatus configured to electrolyze liquid water by applying a current to an anode and a cathode provided on both surfaces of an electrolyte membrane, generate hydrogen at the cathode, and generate oxygen at the anode
Implementation Method 2
an electrochemical hydrogen pressurizing apparatus configured to pressurize the hydrogen at a downstream of the water electrolysis apparatus by applying a current to a pressurizing part anode and a pressurizing part cathode
Implementation Method 3
a solid polymer type water electrolysis apparatus having an electrolyte membrane (an ion exchange membrane), and an anode and a cathode isolated from each other with the electrolyte membrane being interposed therebetween
Data Source
AI summary
A method of controlling a hydrogen/oxygen producing system is a method of controlling a hydrogen/oxygen producing system including a water electrolysis apparatus that electrolyzes liquid water by applying current to an anode and a cathode, and a hydrogen gas pressurizing part that pressurizes hydrogen at downstream of the water electrolysis apparatus by applying current to a pressurizing part anode and a pressurizing part cathode. A controller controls current applied to the water electrolysis apparatus and current applied to the hydrogen gas pressurizing part. When the hydrogen/oxygen producing system is stopped, the controller performs first decompression processing such that a decompression speed of the pressurizing part cathode of the hydrogen gas pressurizing part does not exceed a basic decompression speed and performs second decompression processing such that a decompression speed of the anode of the water electrolysis apparatus does not exceed the decompression speed of the pressurizing part cathode.