Reversible Electrolysis Oxygen Storage Loop
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Solution Overview
Problem
High temperature electrolysis systems, such as solid oxide electrolyzers, face inefficiencies due to the energy consumption required for heating and compressing purging gases, which reduces overall system efficiency.
Innovation Solution
A reversible water electrolysis system that includes hydrogen and oxygen tanks, with a fluidic circuit connecting the electrolyzer to the tanks, allowing for a loop circulation of gases and reducing the need for external heating and compression by using stored oxygen at high pressure and temperature, and a turbo-regulator to generate electricity during gas expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the scavenging gas is heated to high temperature and compressed before being introduced into the reversible electrolyzer, then the proper operation of the reversible solid oxide electrolyzer is ensured, but additional energy consumption increases, reducing overall system efficiency
Solution Approach 1:
The oxygen is pre-compressed to high pressure (20-250 bar) and stored in the oxygen reservoir during electrolyzer mode operation. This preliminary compression eliminates the need for compression during fuel cell mode, as the stored high-pressure oxygen can be directly supplied to the fuel cell after mixing with scavenging gas, thereby eliminating the energy-consuming compression step while ensuring proper operation
Solution Approach 2:
The system uses its own produced oxygen (from electrolysis) to serve as the oxygen source for fuel cell operation. The oxygen produced during hydrogen production is stored and then reused when the system operates in fuel cell mode, making the system self-sufficient and eliminating the need for external oxygen supply infrastructure
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 configuration enhances energy efficiency by minimizing energy loss from gas heating and compression, increasing the overall efficiency of the electrolysis system and enabling effective use of intermittent renewable energy sources.
Implementation Method 1
water molecules are dissociated at the interface formed by cathode 2 and electrolyte 3. This dissociation produces dihydrogen (H2) and oxygen ions (O2)
Implementation Method 2
Oxygen ions O2- migrate through electrolyte 3, and preferentially through solid electrolyte 3 in the case of a SOEC type electrolyzer
Implementation Method 3
oxygen ions O2- migrate through electrolyte 3, and preferentially through solid electrolyte 3 in the case of a SOEC type electrolyzer, and are recombined into dioxygen at the interface between electrolyte 3 and anode 4
Implementation Method 4
the hydrogen tank and/or the oxygen tank include at least one turbo-expander configured to produce electricity during the expansion of hydrogen and/or oxygen at the outlet of said oxygen and/or hydrogen tank
Data Source
Figure 1~2
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Figure 4
AI summary
The present invention relates to a reversible water electrolysis system, comprising at least one reversible electrolyzer-forming device configured to operate in an electrolyzer mode for hydrogen production or in a fuel cell mode for hydrogen consumption, and a hydrogen tank configured to store hydrogen from the device in electrolyzer mode, and to supply hydrogen to the device in fuel cell mode, the system being characterized in that it also comprises an oxygen tank configured to store oxygen from the device in electrolyzer mode for hydrogen production, and to supply oxygen, preferably mixed with air, to the device in fuel cell mode for hydrogen consumption.