CO2 Separation via Concentration Swing Adsorption
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Solution Overview
Problem
Current CO2 capture technologies face challenges in efficiently separating CO2 from combustion gases due to low pressure and concentration, leading to high energy consumption and costs, particularly in post-combustion CO2 capture from fossil fuel power plants.
Innovation Solution
A sorbent-based process using an alkalized substrate, such as alkalized alumina, that adsorbs CO2 at constant pressure and isothermally regenerates with steam, employing concentration swing adsorption and desorption displacement to recover CO2 without requiring pressure or temperature swing adsorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional absorption process is used for CO2 capture from flue gas, then CO2 separation can be achieved, but energy consumption and cost increase significantly
Solution Approach 1:
The patent changes the fundamental parameter of CO2 partial pressure in the flue gas by injecting water, which converts low-partial-pressure CO2 into high-partial-pressure CO2 through condensation. This parameter change enables effective CO2 separation without requiring high energy input for compression or chemical absorption, directly resolving the contradiction between separation effectiveness and energy consumption
Solution Approach 2:
Water acts as an intermediary substance that facilitates CO2 separation. By injecting water into the flue gas, CO2 is converted from a gas phase component to a liquid phase through condensation, enabling easy separation from the gas stream. This intermediary approach achieves effective separation while minimizing energy requirements compared to conventional absorption methods
2Reliability
If CO2 is compressed from 0.1 atm to 150 atm for delivery, then CO2 can be transported, but compression cost and energy consumption increase
Solution Approach 1:
The patent performs preliminary action by condensing CO2 into liquid phase early in the process through water injection, before any compression is needed. This preliminary phase change prepares CO2 for easier transport and subsequent vaporization, eliminating the need for high-energy compression from 0.1 atm to 150 atm and significantly reducing compression energy requirements
Solution Approach 2:
The patent utilizes phase transitions of CO2 between gas, liquid, and vapor phases to achieve transport without high-pressure compression. CO2 is condensed to liquid for easy handling and transport, then vaporized at the destination. This phase transition approach replaces energy-intensive mechanical compression with thermodynamically efficient phase changes
3Productivity
If aqueous amines are used for CO2 capture, then CO2 removal efficiency improves, but cost per ton of CO2 avoided increases
Solution Approach 1:
The patent replaces expensive aqueous amine solutions with water, a cheap and readily available substance. Water is injected into the flue gas, performs its function of CO2 condensation and separation, and then the CO2-rich water can be easily disposed of or treated. This substitution of expensive chemical absorbents with inexpensive water directly reduces the cost per ton of CO2 avoided while maintaining removal efficiency
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 process effectively captures and recovers CO2 with reduced energy consumption and costs, achieving high CO2 recovery rates while maintaining system efficiency and operational simplicity.
Implementation Method 1
passing a gas stream comprising CO2 over a sorbent to adsorb the CO2 to the sorbent
Implementation Method 2
recovering the CO2 by desorbing the CO2 from the sorbent... treating the CO2-containing sorbent with steam to displace the CO2 from the sorbent
Data Source
AI summary
A process for separating a carbon dioxide from a gas stream is disclosed. The process can include passing the gas stream over a sorbent that adsorbs the carbon dioxide by concentration swing adsorption and adsorptive displacement. The sorbent can be regenerated and the carbon dioxide recaptured by desorbing the carbon dioxide from the sorbent using concentration swing adsorption and desorptive displacement. A carbon dioxide separation system is also disclosed. Neither the system nor the process rely on temperature swing or pressure swing adsorption.