SOEC Flush Gas Drying With Adsorbent Regeneration Heat Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The presence of moisture in flush gas air negatively affects the lifetime of solid oxide electrolysis cells, and existing systems lack efficient methods to optimize the performance and extend the life of SOEC stacks while minimizing energy consumption and costs.
Innovation Solution
A process and system utilizing an adsorbent with specific moisture adsorption and desorption temperature ranges to dry flush gas streams, incorporating temperature adjustments and heat exchangers to recover energy, and a sequential operation of adsorbent sections for efficient moisture removal and regeneration, reducing flush gas consumption and pressure drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If moist flush gas is used to flush the oxy side of the SOEC, then the system operation is simpler, but the lifetime of the SOEC stacks is reduced due to moisture damage
Solution Approach 1:
A drying unit with adsorbent material is introduced as an intermediary component between the flush gas source and the SOEC oxy side. This drying unit removes moisture from the flush gas through adsorption, allowing the use of simple ambient air or humid gas while protecting the SOEC from moisture damage. The adsorbent acts as a mediator that selectively interacts with water molecules to prevent them from reaching the electrolysis cell.
2Duration of action of stationary object
If a drying unit is introduced to remove moisture from flush gas, then the SOEC stack lifetime is extended, but the system complexity increases
Solution Approach 1:
The drying unit utilizes porous adsorbent materials (such as molecular sieves, activated alumina, or silica gel) that provide high surface area for moisture adsorption. These porous materials efficiently remove moisture from the flush gas stream while maintaining a compact structure. The porous nature of the adsorbent allows for effective moisture capture without requiring large volumes or complex configurations.
3Reliability
If adsorbent is used to dry flush gas, then moisture removal is effective, but energy consumption increases due to heating requirements for moisture desorption
Solution Approach 1:
The system recovers and reuses the moisture-laden gas stream that exits the drying unit during the desorption phase. Instead of venting this gas to waste, it is redirected to contact with the adsorbent bed, allowing the moisture-containing gas to serve as the desorption medium. This approach eliminates the need for external heating energy while effectively removing moisture from the flush gas, as the desorbed moisture is carried away by the recycled gas stream.
4Productivity
If multiple adsorbent sections are operated in sequence for drying and regeneration, then continuous operation is achieved, but the process complexity increases
Solution Approach 1:
The drying unit is divided into multiple adsorbent sections or beds that can be operated in sequence. While one section is performing drying function for the flush gas, another section undergoes regeneration or moisture desorption. This segmentation allows continuous operation of the SOEC system without interruption, as the adsorbent sections alternate between drying and regeneration modes in a cyclic manner.
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 process enhances the performance and extends the lifetime of SOEC stacks by minimizing moisture impact, achieving energy savings through efficient heat integration and reduced flush gas consumption.
Implementation Method 1
adjusting the temperature of the moist flush gas stream to a temperature within the moisture adsorption temperature range to produce a temperature adjusted moist flush gas stream; operating at least a section of the adsorbent in an adsorption mode by passing the temperature adjusted moist flush gas stream through at least the section of the adsorbent to provide a dried flush gas stream
Implementation Method 2
adjusting the temperature of at least part of the spent flush gas stream to a temperature within the moisture desorption temperature range to produce a temperature adjusted, spent flush gas stream; operating at least a section of the adsorbent in a desorption mode by passing at least a part of the temperature adjusted, spent flush gas stream through at least the section of the adsorbent to desorb moisture bound in the adsorbent
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention regards a process for operating a high-temperature solid oxide electrolysis system suitable for converting a fuel stream into a product stream as well as a system for carrying out the process. The process involves drying a moist flush gas and using the spent flush gas as regeneration gas in the drying unit.