PSA Hydrogen Purification with Layered Adsorbents and CO Monitoring
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Solution Overview
Problem
Existing hydrogen production methods struggle to continuously and cost-effectively comply with the strict ISO international standard for hydrogen quality in fuel cell vehicles (FCVs) due to difficulties in monitoring and removing impurity components like nitrogen and carbon monoxide, leading to high analysis costs and intermittent quality control.
Innovation Solution
A pressure swing adsorption (PSA) device using activated carbon and zeolite adsorbents in a layered configuration to adsorb and remove carbon monoxide and methane impurities, combined with a densitometer for continuous CO concentration monitoring, ensuring the hydrogen meets ISO standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic sampling and analysis of hydrogen gas is performed to ensure ISO standard compliance, then quality control can be verified, but analysis costs increase and continuous quality control cannot be achieved
Solution Approach 1:
The patent implements continuous quality control by monitoring the concentration of canary components (CO and CH4) in real-time during the PSA process, replacing periodic sampling with continuous online detection. This ensures hydrogen quality meets ISO standards at all times without requiring external analysis laboratories.
Solution Approach 2:
The system uses densitometers to continuously measure CO and CH4 concentrations in the hydrogen stream, providing real-time feedback to the control unit. Based on this feedback, the system automatically adjusts PSA operation parameters to maintain impurity levels within ISO standard limits.
2Reliability
If comprehensive analysis of all 14 ISO components is performed, then complete quality verification is achieved, but analysis costs increase significantly
Solution Approach 1:
The patent extracts and focuses analysis on only the critical canary components (CO and CH4) that are most difficult to control and remove during PSA. By monitoring these key impurities rather than all 14 ISO components, the system achieves effective quality verification at reduced cost.
Solution Approach 2:
Instead of performing expensive comprehensive chemical analysis for all 14 components, the system uses densitometers to measure the physical properties (density) of the gas stream, which indirectly provides information about the concentration of canary components. This physical measurement approach is more cost-effective than comprehensive chemical analysis.
3Reliability
If nitrogen concentration is monitored to control hydrogen quality, then impurity removal can be tracked, but nitrogen is difficult to monitor in hydrogen-rich gas after steam reforming
Solution Approach 1:
Instead of monitoring nitrogen concentration (which is difficult in hydrogen-rich gas), the patent inverts the approach by monitoring canary components (CO and CH4) that are easier to detect and more indicative of PSA performance. These canary components serve as proxies for overall impurity control.
Solution Approach 2:
The patent uses CO and CH4 as intermediary indicators (canary components) to assess hydrogen quality. These components are easier to measure with densitometers and provide sufficient information to control PSA operation, serving as mediators between the difficult-to-measure nitrogen concentration and the control system.
4Reliability
If activated carbon and zeolite are used as adsorbents in layered configuration, then impurity removal efficiency increases, but device complexity increases
Solution Approach 1:
The adsorbent bed is segmented into multiple layers with different materials (activated carbon and zeolite) having different adsorption characteristics. This segmentation allows each layer to target specific impurities, improving overall removal efficiency while maintaining manageable complexity through modular layer design.
Solution Approach 2:
The patent uses composite adsorbent structures combining activated carbon and zeolite in layered configurations. This composite approach leverages the complementary adsorption properties of both materials to achieve superior impurity removal compared to single-material adsorbents, while the layered structure organizes the complexity systematically.
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 PSA device enables continuous, online quality control of hydrogen purity, reducing analysis costs and maintaining high-purity hydrogen production, achieving purity levels of 99.97% or more by continuously monitoring and removing impurities.
Implementation Method 1
an adsorption tower configured to introduce hydrogen gas and adsorb impurity components in the hydrogen gas by using a pressure swing adsorption (PSA) method
Implementation Method 2
adsorb impurity components in the hydrogen gas by using a pressure swing adsorption (PSA) method
Implementation Method 3
a densitometer configured to detect a concentration of CO in the hydrogen gas discharged from the adsorption tower
Data Source
AI summary
According to one aspect of the present invention, a pressure swing adsorption (PSA) device includes an adsorption tower configured to introduce hydrogen gas and adsorb impurity components in the hydrogen gas by using a pressure swing adsorption (PSA) method, an adsorbent of one layer made of activated carbon or an adsorbent of two layers in which activated carbon and zeolite are stacked being disposed in the adsorption tower, the hydrogen gas containing carbon monoxide (CO) of 0.5 vol % or more and 6.0 vol % or less and methane (CH4) of 0.4 vol % or more and 10 vol % or less as the impurity components; and a densitometer configured to detect a concentration of CO in the hydrogen gas discharged from the adsorption tower, wherein the impurity components are adsorbed and removed to cause the CO concentration measured by the densitometer to fall below a threshold.