Electrolysis Method Using Redox Auxiliary for High-Pressure Hydrogen
Solution Overview
Problem
Existing electrolysis methods for producing hydrogen under high pressure are inefficient and costly due to the need for mechanical compression and increased gas permeation through membranes, which reduces efficiency.
Innovation Solution
A method involving electrolysis with a reversibly reducible and oxidizable auxiliary in an electrolytic cell, followed by a chemical reaction in a high-pressure reactor using a catalyst to produce hydrogen indirectly, allowing for hydrogen production at high pressure without mechanical compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If electrolysis is performed at high pressure, then hydrogen production pressure is improved, but gas cross-permeation through the membrane increases and efficiency deteriorates
Solution Approach 1:
The system divides the hydrogen production process into two separate stages: low-pressure electrolysis and high-pressure chemical conversion. The electrolysis cell operates at low pressure (avoiding membrane permeation losses), while the high-pressure hydrogen is generated in a separate reactor through chemical reaction of the reduced auxiliary with protons, thus resolving the contradiction between production pressure and efficiency
Solution Approach 2:
A reversible auxiliary substance acts as an intermediary carrier. During electrolysis, the auxiliary is reduced at the cathode; subsequently, in the high-pressure reactor, the reduced auxiliary reacts with protons to generate high-pressure hydrogen. This intermediary enables indirect hydrogen production at high pressure without subjecting the electrolysis membrane to high pressure, maintaining efficiency while achieving the desired output pressure
2Stress or pressure
If mechanical compression is used to increase hydrogen pressure, then hydrogen storage pressure is improved, but device complexity and cost increase
Solution Approach 1:
The invention replaces the mechanical compression system with a chemical reaction system. Instead of using compressors or pumps to mechanically increase hydrogen pressure, the system uses a chemical reaction between the reduced auxiliary and protons in a high-pressure reactor to directly generate hydrogen at the desired pressure (e.g., 500 bar), thereby eliminating complex mechanical compression equipment and associated costs
3Stress or pressure
If electrolysis is performed at high pressure, then hydrogen production pressure is improved, but construction cost of electrolysis apparatus increases
Solution Approach 1:
The system segments the high-pressure requirement from the electrolysis process. The electrolysis apparatus is designed for low-pressure operation with standard membranes and components, while the high-pressure hydrogen generation occurs in a separate, purpose-built reactor. This segmentation allows the electrolysis portion to be manufactured at lower cost, avoiding the need for expensive high-pressure-rated electrolysis cells and membranes
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
Enables efficient production of hydrogen at high pressures, such as 500 bar, while reducing the complexity and cost of electrolysis equipment and minimizing gas permeation issues, thus avoiding the inefficiencies of high-pressure electrolysis.
Implementation Method 1
an electrical voltage being applied between the anode and the cathode, such that oxygen is formed at the anode and the auxiliary is reduced at the cathode
Implementation Method 2
protons and the reduced auxiliary being brought into contact with a catalyst outside the electrochemical cells, in a reactor, such that the reduced auxiliary is oxidized and hydrogen is formed, under pressure, from the protons
Data Source
AI summary
Method for electrolysis, wherein H2O is brought into contact with an anode, and a catholyte is brought into contact with a cathode, wherein the catholyte contains an auxiliary, wherein an electrical voltage is applied between the anode and the cathode such that oxygen is formed at the anode and the auxiliary is reduced at the cathode, and wherein protons and the reduced auxiliary are brought into contact with a catalyst such that the reduced auxiliary is oxidized and hydrogen is formed from the protons. By means of the auxiliary, the electrolysis can be carried out under low pressure, and hydrogen can still be obtained at high pressure. This facilitates the construction of the electrolytic cell and prevents an efficiency-reducing gas cross-permeation.