Electrolysis Plant Buffer Tank for Hydrogen Purity Control
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Solution Overview
Problem
Existing electrolysis systems face inefficiencies and safety concerns due to the need for complex and costly downstream gas cleaning processes to remove oxygen from hydrogen product gas, leading to discarding of high-value hydrogen and requiring large nitrogen inertization systems.
Innovation Solution
A method that involves a buffer tank to store hydrogen of low oxygen concentration, which is supplied to the gas separator as needed to dilute and lower the oxygen concentration in the hydrogen product gas, thereby avoiding the need for complete inertization and discarding of hydrogen, and allowing for more efficient operation and reduced nitrogen system requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complex downstream gas cleaning processes are used to remove oxygen from hydrogen product gas, then gas purity is improved, but system complexity and cost increase
Solution Approach 1:
The patent applies preliminary action by storing high-purity hydrogen in advance in a buffer tank during normal operation. When oxygen concentration exceeds limits, this pre-stored hydrogen is immediately supplied to the gas separator, avoiding the need for complex downstream cleaning processes and enabling rapid response to quality deviations.
Solution Approach 2:
The patent extracts the high-purity hydrogen component from the system by storing it separately in a buffer tank during normal operation. This extracted pure hydrogen is then used to dilute and replace contaminated hydrogen in the gas separator, effectively removing the oxygen contamination issue without requiring complex cleaning equipment.
2Manufacturing precision
If complex downstream gas cleaning processes are used to remove oxygen from hydrogen product gas, then gas purity is improved, but production loss increases
Solution Approach 1:
The patent recovers hydrogen that would otherwise be discarded due to oxygen contamination. By storing pure hydrogen in a buffer tank and using it to dilute contaminated hydrogen in the gas separator, the system maintains gas purity requirements while preserving and reusing the hydrogen product, thereby reducing production loss.
Solution Approach 2:
The patent converts the harmful effect of oxygen contamination into a benefit by using the buffer tank to store pure hydrogen during normal operation. This pre-stored pure hydrogen then serves as a corrective measure when contamination occurs, turning the potential waste scenario into an opportunity to maintain both purity and production efficiency.
3Reliability
If large nitrogen inertization systems are used to ensure safety, then safety is improved, but system complexity and cost increase
Solution Approach 1:
The patent extracts the safety function from the large nitrogen inertization system by introducing a buffer tank that stores pure hydrogen. This buffer tank acts as a rapid response mechanism to dilute contaminated hydrogen and prevent dangerous oxygen-hydrogen mixtures, thereby maintaining safety with a smaller, more efficient system configuration.
Solution Approach 2:
The buffer tank serves as an intermediary between the electrolyzer and gas separator, providing a reservoir of pure hydrogen that can be rapidly supplied to maintain safety. This intermediary buffer tank reduces the need for large nitrogen storage systems while ensuring safe operation by preventing dangerous gas mixture formation.
4Manufacturing precision
If hydrogen product gas is discarded when oxygen concentration exceeds limits, then gas purity is maintained, but productivity decreases
Solution Approach 1:
The patent recovers hydrogen that would otherwise be discarded by using the buffer tank to supply pure hydrogen to the gas separator when oxygen concentration exceeds limits. This allows the system to maintain gas purity specifications while preserving the hydrogen product and continuing production, thereby eliminating the need to discard contaminated gas.
Solution Approach 2:
The patent applies preliminary action by pre-storing pure hydrogen in the buffer tank during normal operation. When oxygen contamination occurs, this pre-stored hydrogen is immediately supplied to dilute the contaminated gas in the gas separator, allowing continuous production while maintaining purity standards without discarding hydrogen.
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 reduces the oxygen concentration in hydrogen product gas without discarding produced hydrogen, increases hydrogen yield, and allows for a smaller nitrogen system, thereby improving system efficiency and safety while minimizing downtime and maintenance.
Implementation Method 1
hydrogen of a low oxygen concentration is removed from a buffer tank and supplied as needed to the gas separator, so that the oxygen concentration in the hydrogen product gas is lowered
Implementation Method 2
water is decomposed into hydrogen and oxygen by means of water electrolysis
Implementation Method 3
The protons pass through the proton exchange membrane
Implementation Method 4
the oxygen is removed from the hydrogen product gas by reaction of the oxygen in a recombination catalyst (DeOxo catalyst) with the hydrogen to form water
Data Source
AI summary
The invention relates to a method for operating an electrolysis plant for producing hydrogen and oxygen as product gases, wherein the hydrogen product gas, which additionally contains oxygen as a foreign gas, is fed from an electrolyser to a downstream gas separator, wherein when a predefined limit value for the oxygen concentration in the hydrogen product gas is exceeded, hydrogen having a low oxygen concentration is fed to the gas separator such that the oxygen concentration in the hydrogen product gas is lowered. The invention further relates to a corresponding electrolysis plant.