Multi-Stage Water Separation for PEM Electrolyzer Hydrogen Drying
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Solution Overview
Problem
Existing methods for electrically generating hydrogen from water using electrolyzers often result in hydrogen being produced with significant water vapor or droplets, which is undesirable for storage and transport, as it requires extensive water removal before storage.
Innovation Solution
A multi-stage water separation device comprising a mechanical, thermal, and coagulation separation stage, connected to the electrolyzer output, effectively removes water vapor and droplets from hydrogen, ensuring it is produced almost completely dry, with the option to recycle water and operate at higher temperatures for efficient hydrogen production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single-stage water separator is used, then the device complexity is low, but the water removal efficiency is insufficient and hydrogen cannot be completely dried
Solution Approach 1:
The water separation process is divided into three distinct stages: mechanical separation (removing large water droplets), thermal separation (condensing and removing water vapor through cooling), and coagulation separation (coagulating fine droplets for final removal). Each stage targets different sizes and states of water contaminants, achieving complete drying through sequential processing rather than relying on a single complex device.
2Reliability
If hydrogen is stored with water content, then storage capacity is maintained, but water must be almost completely removed before storage in high pressure pipelines or mobile applications
Solution Approach 1:
The multi-stage water separation device performs complete water removal as a preliminary action immediately after hydrogen generation, ensuring hydrogen is completely dried before storage or transport. The mechanical separation stage removes large droplets first, followed by thermal separation condensing water vapor, and coagulation separation eliminating fine droplets, so that when hydrogen reaches storage facilities, it is already ready for high-pressure storage without requiring additional water removal infrastructure.
3Productivity
If electrolyzer operates at higher temperature for efficient hydrogen production, then productivity increases, but water vapor content in produced hydrogen increases
Solution Approach 1:
The thermal separation stage utilizes phase transition (condensation) to remove water vapor from hydrogen. By cooling the hydrogen stream, water vapor condenses into liquid water that can be separated and removed. This allows the electrolyzer to operate at higher temperatures for improved efficiency while the downstream thermal separation stage recovers the water content through controlled condensation, preventing water accumulation in the hydrogen product.
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
The solution enables efficient removal of water from hydrogen, allowing for effective storage and transport without loss of hydrogen, and reduces energy requirements for cooling, while maintaining high electrolyzer efficiency and producing dry hydrogen at suitable pressures for storage and transport.
Implementation Method 1
a first mechanical separation stage
Implementation Method 2
a first mechanical separation stage
Implementation Method 3
a second thermal separation stage, which is downstream of the first mechanical separation stage
Implementation Method 4
a third coagulation separation stage, which is downstream of the second thermal separation stage in the multi-stage water separation device and includes a coagulator
Implementation Method 5
an electrolyzer of PEM or AEM type, having an inlet for supplying water, a first outlet for hydrogen enriched with water and/or water vapor and generated in the electrolyzer
Data Source
Figure 1
AI summary
The invention relates to a device (1) and a method for electrically generating hydrogen from water. The device comprises the following: an electrolyzer (2) of PEM or AEM type, having an inlet (5) for supplying water from a water reservoir (3), a first outlet (6) for hydrogen enriched with water and/or steam and generated in the electrolyzer (2), and a second outlet (7) for oxygen and water; and a water separation device (9) with several separation stages, wherein an inlet (8) is connected to the first outlet (6) and the outlet (16) of which is configured to discharge dried hydrogen.The multiple separation stages comprise the following: a first mechanical separation stage (10), a second thermal separation stage (11) which is downstream of the first mechanical separation stage (10) in the multi-stage water separation device (9), and a third coagulation separation stage (12) which is downstream of the second thermal separation stage (11) in the multi-stage water separation device (9) and includes a coagulator.