Integrated CO2 Adsorption-Cryogenic Separation for Stable High Purity
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Solution Overview
Problem
Current CO2 separation technologies, such as chemical absorption and pressure swing adsorption, face limitations in achieving high CO2 purity and recovery efficiency, especially when dealing with feed gases containing less than 60% CO2, which hinders industrial applications like geological storage and enhanced oil recovery.
Innovation Solution
An integrated process combining an adsorption unit with a cryogenic unit, where the adsorption unit performs a pre-separation of CO2, followed by gas homogenization and intermediate compression to stabilize flow and pressure, before the cryogenic unit achieves final separation, optimizing CO2 recovery and purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical absorption with amines is used to separate CO2, then CO2 purity greater than 99% is achieved, but large amount of steam is required and high operating cost is incurred
Solution Approach 1:
The invention divides the CO2 separation process into two distinct stages: a first separation stage using chemical absorption with amines to achieve high purity CO2, and a second separation stage using physical absorption with a porous material to concentrate CO2 from low-concentration streams. This segmentation allows each stage to operate optimally for its specific function, reducing overall steam consumption while maintaining high purity output.
Solution Approach 2:
The invention introduces an intermediary physical absorption stage using a porous material (such as metal organic frameworks or zeolites) between the feed gas and the final CO2 product. This intermediary stage pre-concentrates CO2 from low-concentration streams (1-50% CO2) before feeding to the chemical absorption stage, reducing the load and steam requirement of the amine washing system.
2Manufacturing precision
If chemical absorption with amines is used to separate CO2, then CO2 purity greater than 99% is achieved, but high operating cost is incurred
Solution Approach 1:
The process is segmented into two stages: physical absorption for CO2 concentration and chemical absorption for final purification. The physical absorption stage using regenerable porous materials reduces operating costs by requiring less energy-intensive regeneration compared to traditional amine washing, while the second stage ensures high purity output.
Solution Approach 2:
The invention changes the absorption mechanism from purely chemical (amines) to a combination of physical and chemical absorption. The physical absorption stage operates at lower energy consumption levels for regeneration, while the chemical absorption stage handles only the final purification step, overall reducing operating costs while maintaining CO2 purity greater than 99%.
3Use of energy by moving object
If pressure swing adsorption is used to separate CO2, then steam consumption is reduced, but CO2 purity greater than 90% cannot be achieved from feed gas low in CO2
Solution Approach 1:
The invention segments the separation process into a first stage using pressure swing adsorption or similar physical absorption methods to concentrate CO2 from low-concentration feed gases, followed by a second stage using chemical absorption with amines to achieve final high purity CO2. This segmentation enables the system to overcome the purity limitation of single-stage physical absorption while maintaining low steam consumption.
Solution Approach 2:
The invention introduces an intermediary chemical absorption stage using amines after the physical absorption stage. This intermediary stage takes the CO2-enriched stream from the low-steam physical absorption process and achieves the final high purity CO2 output, bridging the gap between low energy consumption and high purity requirements.
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 integrated system achieves a CO2 recovery yield of approximately 90% and purity suitable for industrial applications, such as geological storage and enhanced oil recovery, while reducing operational costs and overcoming limitations of existing methods.
Implementation Method 1
an adsorption unit for separating a flow of CO2 from a feed gas containing CO2 into a first flow of CO2 enriched and a first flow of CO2 depleted
Implementation Method 2
a cryogenic unit for separating the first flow rich in CO2 from the adsorption unit into a second flow rich in CO2 and a second flow poor in CO2
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention concerns integrated method and installation using an adsorption unit (3) and a cryogenic unit (9), wherein a feeding gas containing CO2 is conveyed to an adsorption unit (3) where it is separated into a first flow enriched in CO2 (6) and a first flow depleted in CO2 (5), the first flow enriched in CO2 being conveyed to the cryogenic unit (9) where it is separated into a second flow rich in CO2 (11) and a second flow depleted in CO2 (10). The first flow enriched in CO2 (6) derived from the adsorption unit (3) is sent to homogenizing means (17), such as a storage volume or the like, for attenuating the cyclic variations of flow rate, of composition and/or of gas pressure, then subjected to at least one intermediate compression step (7) prior to its input into the cryogenic unit (9). The first flow enriched in CO2 (6) exiting the adsorption unit (3) contains between 40 and 95 %, preferably between 60 and 85 % of CO2.