Method and installation for the electrolytic production of liquid hydrogen
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Solution Overview
Problem
Existing methods for electrolytic hydrogen production struggle with dynamic control of energy requirements, particularly when faced with fluctuations in renewable energy sources.
Innovation Solution
The method involves intermediate storage of hydrogen downstream of electrolysis and upstream of liquefaction, allowing for flexible control of energy requirements and enabling continuous operation despite fluctuations in electrolysis output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrolysis output is increased to meet higher hydrogen demand, then hydrogen production quantity increases, but the system becomes difficult to control due to dynamic fluctuations in renewable energy sources
Solution Approach 1:
The patent applies preliminary action by pre-cooling hydrogen gas in a heat exchanger using cold from the liquid hydrogen storage tank before it enters the electrolysis unit. This pre-cooling action prepares the hydrogen for more efficient electrolysis and reduces the thermal load on subsequent processing steps, allowing the system to handle variable energy input more effectively while maintaining productivity
2Temperature
If conventional cooling circuits with nitrogen precooling are used, then hydrogen can be cooled to liquefaction temperature, but the system complexity increases and energy efficiency decreases
Solution Approach 1:
The patent merges the cooling function with the liquid hydrogen storage system itself. The storage tank serves dual purposes: storing liquid hydrogen product and providing cold energy for pre-cooling incoming hydrogen gas through a heat exchanger. This eliminates the need for separate nitrogen precooling circuits and reduces overall system complexity while achieving the required temperature reduction
Solution Approach 2:
The liquid hydrogen storage tank serves itself by providing the cold energy needed for its own product's pre-cooling. The cold hydrogen stored in the tank automatically cools incoming warm hydrogen gas through the heat exchanger, creating a self-sustaining cooling cycle that reduces external energy input and simplifies the cooling system architecture
3Productivity
If electrolysis operates continuously at high output, then hydrogen production increases, but the system cannot adapt to fluctuations in renewable energy supply
Solution Approach 1:
The patent implements dynamics by creating a two-stage hydrogen production system where electrolysis operates continuously at optimized output and a second hydrogen source (from alternative electrolysis or storage) supplements production. This dynamic configuration allows the system to maintain high overall productivity while adapting to variable renewable energy availability by adjusting the contribution of each hydrogen source
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 allows for more flexible and continuous production of liquid hydrogen, effectively reconciling the dynamic differences between electrolysis and liquefaction processes.
Implementation Method 1
a water-containing feed (1) is subjected to electrolysis while receiving an anode raw gas (3), rich in oxygen and containing hydrogen, and a cathode raw gas (2) which is depleted of oxygen and rich in hydrogen
Implementation Method 2
at least a part of the liquid hydrogen product formed in the liquefaction unit (L) is fed into a heat exchanger (K) in order to cool the cathode raw gas (2)
Implementation Method 3
a liquefaction unit (L) which is designed to liquefy a gas stream rich in hydrogen
Data Source
AI summary
The invention relates to a method (100) for the electrolytic production of a liquid hydrogen product (4), in which a water-containing feed is subjected to an electrolysis (E) while receiving an anode raw gas (3), rich in oxygen and containing hydrogen, and a cathode raw gas (2) which is depleted of oxygen and rich in hydrogen, wherein the cathode raw gas (2) downstream of the electrolysis (E) is subjected to a purification (R), a compression (K), and a liquefaction (L), characterized in that the cathode raw gas (2) at least partially undergoes intermediate storage (Z) downstream of the electrolysis (E) and upstream of the liquefaction (L). A corresponding installation is also proposed.