SOEC Steam Generation Using Hydrogen Combustion at Variable Load
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Solution Overview
Problem
The expansion of the steam amount that can be electrolyzed in a solid oxide electrolysis cell (SOEC) leads to increased facility size and operating costs, inefficient operating conditions, and higher power consumption during low-load operations, particularly when the steam amount is less than the design point.
Innovation Solution
A hydrogen production system that includes a solid oxide electrolysis cell, a steam generator, and a combustor where a part of the hydrogen in discharged steam is combusted to generate additional heat for steam production, using the combustion gas to heat-exchange with supply water, thereby increasing the steam amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the steam amount that can be electrolyzed in the SOEC is expanded, then the productivity of hydrogen production is improved, but the facility size (boiler or heat exchanger) becomes larger, causing an increase in operating costs
Solution Approach 1:
The patent combines the boiler and heat exchanger into a single integrated steam generator. The steam generator includes a combustion chamber where hydrogen from the SOEC outlet is combusted to generate heat, and a heat exchange section where this heat is transferred to water to generate steam. This merging of functions allows the system to handle varying steam demands without requiring separate, oversized facilities for each function.
Solution Approach 2:
The system uses the hydrogen produced by the SOEC (which would otherwise be wasted or require separate handling) as fuel for the combustion chamber. This self-service approach allows the system to generate its own heating energy internally, eliminating the need for external fuel sources and reducing the size of required heating facilities.
2Adaptability or versatility
If the facility is designed under a condition in which the amount of steam electrolyzed is large, then the response to nonsteady operation is improved, but the specification becomes excessive, causing inefficient operation and increased operating costs during normal conditions
Solution Approach 1:
The steam generator is designed with a combustion chamber that can dynamically adjust the combustion of hydrogen based on real-time steam demand. The system can vary the amount of hydrogen combusted to match the actual steam required by the SOEC, rather than operating at a fixed high capacity. This dynamic adjustment allows efficient operation across different load conditions while maintaining the ability to respond to nonsteady operation.
3Productivity
If the steam amount is decreased during low-load operation, then the operating costs are reduced, but the temperature of the supplied steam is decreased, electrolytic power is increased, and operating costs are increased
Solution Approach 1:
The system changes the temperature parameter of the supplied steam by controlling the combustion process in the combustion chamber. Even during low-load operation, the combustion of hydrogen can be adjusted to maintain adequate steam temperature, preventing the need to increase electrolytic power. This parameter control allows the system to operate efficiently across different load levels without sacrificing steam temperature.
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 system suppresses production costs and expands the range of electrolyzable steam, maintaining efficient operation across varying load conditions by optimizing steam generation.
Implementation Method 1
a combustor that combusts a part of hydrogen contained in steam discharged from a hydrogen electrode of the SOEC
Implementation Method 2
the steam generator is configured such that at least a part of the supply water is heated to generate at least a part of the steam by exchanging heat between at least the part of the supply water and a gas containing a combustion gas generated in the combustor
Implementation Method 3
a solid oxide electrolysis cell (SOEC) that electrolyzes steam
Data Source
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AI summary
This hydrogen production system comprises: a solid oxide electrolysis cell (SOEC) that electrolyzes water vapor; a water vapor generation device that heats supply water to generate water vapor; and a combustor that partially burns hydrogen included in water vapor discharged from a hydrogen electrode of the SOEC. The water vapor generation device is configured such that the supply water is at least partially heated through heat exchange between at least part of the supply water and gas including combustion gas generated in the combustor so as to produce at least part of the water vapor.