Recuperative Hydrogen Purification Layout for Low-Pressure Power-to-X
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Solution Overview
Problem
Current Power-to-X systems face high investment costs and low efficiency due to complex system concepts and high storage pressures, limiting the economical use of renewable energy storage and conversion, especially in stationary applications.
Innovation Solution
A simplified Power-to-X system with an electrolyzer and energy converter connected via a hydrogen line, incorporating a chemical reactor for catalytic oxygen removal, heat exchangers, a water separator, storage tank, and humidifier, which reduces hydrogen storage pressure and purity requirements, and uses heat recovery to minimize corrosion and hydrogen losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If high storage pressure (350-750 bar) is used to achieve high energy density for hydrogen storage, then storage volume is reduced and driving performance is enabled, but corrosion from water vapor or oxygen occurs and complex purification processes are required
Solution Approach 1:
The patent changes the pressure parameter from high (350-750 bar) to low (1-10 bar), which fundamentally alters the requirements for hydrogen purification and storage materials. At low pressure, corrosion risks are significantly reduced and simpler purification methods suffice, while the system compensates for lower energy density through direct electrolysis-storage conversion without compression
Solution Approach 2:
The patent converts the typically harmful water vapor produced during electrolysis from a corrosion risk into a beneficial resource by using it for humidifying the hydrogen before it enters the fuel cell, eliminating the need for complex drying systems and reducing overall system complexity
2Reliability
If complex purification processes (drying and catalytic oxygen removal) are implemented to prevent corrosion at high pressure, then corrosion is prevented, but investment costs increase and hydrogen losses occur
Solution Approach 1:
By changing the storage pressure parameter to low levels (1-10 bar), the patent eliminates the need for complex purification processes. The lower pressure reduces corrosion risks to acceptable levels without requiring expensive drying systems or catalytic oxygen removal, thereby simplifying the overall system while maintaining reliability
Solution Approach 2:
The patent extracts and removes the complex purification components (drying systems and catalytic oxygen removal) from the system by operating at low pressure where these components are no longer necessary, thereby reducing device complexity and investment costs while maintaining sufficient corrosion protection
3Volume of moving object
If high pressure storage is used to limit storage volumes, then storage efficiency is improved, but system complexity and investment costs increase
Solution Approach 1:
The patent changes the pressure parameter from high to low (1-10 bar) and accepts larger storage volumes as a trade-off, thereby eliminating the need for expensive compressors and complex high-pressure containment systems. This parameter change fundamentally simplifies the system architecture while maintaining economic viability through reduced investment costs
4Reliability
If complete purification of hydrogen is implemented to prevent corrosion, then corrosion is prevented, but hydrogen losses due to catalytic reaction occur
Solution Approach 1:
By changing the storage pressure to low levels (1-10 bar), the patent reduces corrosion risks to acceptable levels without requiring catalytic oxygen removal processes. This eliminates the hydrogen losses associated with catalytic reactions while maintaining sufficient corrosion protection through the simplified low-pressure system design
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 lowers investment costs and enhances efficiency by reducing corrosion risks and hydrogen losses, enabling cost-effective and flexible storage and conversion of renewable energy, while maintaining high energy density and flexibility.
Implementation Method 1
The hydrogen produced in electrolysis is first freed from residual oxygen through catalytic oxidation of the oxygen with hydrogen
Implementation Method 2
the hydrogen cools via the first heat exchanger, the dew point decreases and water condenses
Implementation Method 3
water condenses. The hydrogen therefore contains less water and is in a saturated state at a low temperature
Implementation Method 4
the cooled hydrogen stream is reheated via the second heat exchanger (recuperator) and fed into the storage tank
Implementation Method 5
splitting water into hydrogen and oxygen by supplying electrical energy
Implementation Method 6
an energy converter, which is conveniently a fuel cell
Data Source
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Figure 2
AI summary
The invention relates to a power-to-X system (1) comprising an electrolyzer (2) and an energy converter (12) which are connected together via a hydrogen line (13). The system additionally comprises a chemical reactor (4) for catalytically removing oxygen, a first heat exchanger (5), a water separator (7), a store (10), and a humidifier (11) which are connected into the hydrogen line (13) in the stated order one behind the other between the electrolyzer (2) and the energy converter (12). A second heat exchanger (14) is arranged in the hydrogen line (13) such that a first side of the second heat exchanger (14) is arranged in front of the first heat exchanger (5) and a second side of the second heat exchanger (14) is arranged downstream of the water separator (7) in the hydrogen line (13). The invention additionally relates to a method for storing and flexibly using renewable energies.