Parallel Hydrogen Generation Lines for Continuous CO Removal
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Solution Overview
Problem
Conventional hydrogen generating systems fail to continuously supply hydrogen-containing gas with sufficiently decreased CO concentration to fuel cells, leading to frequent interruptions in fuel cell operation due to ammonia poisoning of selective oxidation catalysts in CO removers.
Innovation Solution
A hydrogen generating system with multiple devices connected in parallel, where a controller manages the supply of oxidizing gas and hydrogen-containing gas to CO removers, allowing for continuous regeneration of the catalyst by alternating between supplying oxidizing gas and stopping its supply, thereby maintaining stable CO concentration and preventing catalyst degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the operating temperature of the CO remover is increased to regenerate the selective oxidation catalyst, then the catalyst regeneration effect is improved, but the hydrogen-containing gas supply to the fuel cell is interrupted
Solution Approach 1:
The system divides a single hydrogen generation line into multiple parallel lines (first hydrogen generation line with CO remover, second hydrogen generation line without CO remover). This segmentation allows one line to be regenerated while the other continues supplying hydrogen to the fuel cell, resolving the contradiction between catalyst maintenance and continuous operation.
Solution Approach 2:
The system dynamically switches between different hydrogen generation lines based on operational needs. The controller activates the first line during normal operation and switches to the second line during catalyst regeneration, enabling continuous hydrogen supply while maintaining catalyst activity through periodic regeneration cycles.
2Reliability
If air supply is stopped to regenerate the selective oxidation catalyst, then catalyst regeneration is achieved, but CO concentration in the hydrogen-containing gas increases
Solution Approach 1:
The second hydrogen generation line acts as an intermediary solution. When the first line's CO remover requires regeneration, the second line temporarily supplies hydrogen-containing gas (with higher CO concentration) to the fuel cell, allowing the first line to regenerate the catalyst without interruption to the overall system.
Solution Approach 2:
The system temporarily accepts higher CO concentration from the second line during regeneration periods, discarding the strict CO concentration requirement temporarily, then recovers by switching back to the first line once regeneration is complete, maintaining long-term system reliability.
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 system ensures continuous and stable supply of hydrogen-containing gas to fuel cells, preventing catalyst degradation and allowing for prolonged fuel cell operation without interruptions.
Implementation Method 1
a steam reforming reaction is used as the reforming reaction. In the steam reforming reaction, hydrocarbon that becomes the raw material and water vapor react with each other at a high temperature of about 600°C to about 700°C using a Ni-based, Ru-based, or Rh-based reforming catalyst
Implementation Method 2
a CO remover that decreases a concentration of carbon monoxide contained in the hydrogen-containing gas by using a selective oxidation catalyst and an oxidizing gas
Implementation Method 3
When ammonia is supplied to the CO remover, the catalyst activity is decreased depending on a catalyst species (for example, Ru) of the selective oxidation catalyst loaded in the CO remover
Data Source
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AI summary
In a hydrogen generating system, a controller is configured to cause at least one of hydrogen generating devices to perform a second action to supply an oxidizing gas and a hydrogen-containing gas to a carbon monoxide (CO) remover while at least another of the hydrogen generating devices performs a first action to supply the hydrogen-containing gas to the CO remover with supply of the oxidizing gas to the CO remover stopped. The controller is configured to close the hydrogen supply passage sealing valve of the at least another of the plurality of hydrogen generating devices that currently performs the first action to mix the hydrogen-containing gas discharged from the CO remover of the at least another of the plurality of hydrogen generating devices that currently performs the first action into the raw material through the recycle passage.