Three-Product PSA System for Hydrogen and CO2 Recovery
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Solution Overview
Problem
Current hydrogen production processes face challenges in achieving cost-effective and efficient CO2 recovery, particularly due to the need for high-pressure co-purge streams and complex segmented adsorber systems, which increase costs and complexity.
Innovation Solution
A three-product pressure swing adsorption (PSA) system that produces three distinct product streams: a high-pressure hydrogen stream, an intermediate-pressure vent gas stream, and a low-pressure CO2-rich tail gas stream, eliminating the need for a high-pressure co-purge stream and segmented adsorber vessels, thereby simplifying the process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a high-pressure CO2 co-purge stream is used in the PSA unit, then CO2 recovery is improved, but process cost and complexity increase
Solution Approach 1:
The patent extracts the CO2 separation function from the traditional two-stream PSA approach and concentrates it into a single adsorber vessel. By using a single bed that produces three distinct pressure streams (high-pressure H2, intermediate-pressure CO2, and low-pressure tail gas), the system eliminates the need for complex segmented adsorbers and high-pressure co-purge infrastructure while achieving superior CO2 recovery
Solution Approach 2:
The patent segments the pressure levels within a single adsorber vessel to produce three distinct product streams at different pressures. This internal pressure segmentation allows CO2 to be recovered at intermediate pressure without requiring external high-pressure co-purge streams, thereby reducing process complexity while maintaining high CO2 recovery
2Manufacturing precision
If segmented adsorber vessels with isolation valves are used, then CO2 separation precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple adsorber vessels into a single adsorber that can produce three distinct product streams simultaneously. This consolidation eliminates the need for isolation valves and complex inter-vessel piping while achieving the same or better separation precision through internal pressure zone management within the single bed
3Productivity
If traditional PSA with combustion of tail gas is used, then hydrogen production is maintained, but CO2 emissions increase
Solution Approach 1:
The patent converts the harmful CO2-rich tail gas that would normally be combusted into a valuable low-pressure CO2 product stream. By recovering CO2 at low pressure directly from the adsorber, the system eliminates combustion emissions while maintaining hydrogen production, transforming a harmful waste stream into a recoverable resource
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 approach allows for improved hydrogen separation and CO2 recovery with reduced operational complexity and costs, enhancing process economics and flexibility, while avoiding impurity build-up and non-permeate losses, thus capturing more CO2 effectively.
Implementation Method 1
a PSA adsorbent layer to selectively adsorb CO2 from the feed gas mixture
Implementation Method 2
The feed gas mixture is introduced to a three-product pressure swing adsorption (PSA) system
Data Source
AI summary
A three-product PSA system which produces three product streams from a feed gas mixture comprising a light key component, at least one heavy key component, and at least one intermediate key component is described. The three-product PSA system produces a high pressure product stream enriched in the light key component, a low pressure tail gas stream enriched in the at least one heavy key component, and an intermediate pressure vent gas stream enriched in the at least one intermediate key component.