Circulating Moving Bed for CO2 Separation
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Solution Overview
Problem
Current CO2 capture technologies face challenges in efficiently separating CO2 from combustion flue gases due to low pressure and concentration, leading to high energy consumption and costs, particularly in post-combustion processes where CO2 is present at low pressures and concentrations.
Innovation Solution
A circulating moving bed system utilizing a sorbent that adsorbs CO2 through concentration swing adsorption and desorbs using steam, eliminating the need for pressure or temperature swings, allowing for continuous operation at constant pressure and temperature, with the sorbent being regenerable and capable of handling high CO2 concentrations in the regeneration stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional absorption processes are used for CO2 capture from flue gas, then CO2 can be separated, but energy consumption and cost increase significantly due to the need for compression from 0.1 atm to 150 atm
Solution Approach 1:
The patent changes the operating parameters from conventional high-pressure compression (0.1 atm to 150 atm) to near-ambient pressure operation. The moving bed adsorption system operates at approximately 1 atm, eliminating the need for energy-intensive compression while achieving 90%+ CO2 recovery through the cyclic adsorption-desorption process using temperature swing between day and night temperatures.
Solution Approach 2:
The system utilizes free temperature swing between day and night environmental temperatures to drive the adsorption and desorption cycles. During the day, higher temperatures promote desorption of CO2 from the adsorbent, while nighttime cooling enables adsorption, eliminating the need for external heating or cooling energy inputs.
2Quantity of substance
If aqueous amine absorption technology is used for CO2 capture, then CO2 can be separated, but the cost of electricity increases by 86% from 64 cents/kWh to 118.8 cents/kWh
Solution Approach 1:
The patent replaces the conventional mechanical/thermal absorption process (aqueous amines requiring heat input and compression) with a physical adsorption process using solid adsorbent materials. This substitution eliminates the need for thermal energy input and high-pressure compression, reducing electricity costs while achieving the same CO2 separation capability.
Solution Approach 2:
The system changes from operating at high pressure (150 atm) and requiring thermal energy input to operating at near-ambient pressure (1 atm) and utilizing free temperature swing. This parameter change dramatically reduces operational costs while maintaining effective CO2 capture.
3Quantity of substance
If pressure swing adsorption is used for CO2 capture, then CO2 can be separated, but large pressure ratios are required which increase capital costs and energy consumption
Solution Approach 1:
The patent replaces pressure swing adsorption (requiring complex pressure control systems and high pressure ratios) with temperature swing adsorption using free environmental temperature variations. This substitution simplifies the device by eliminating pressure control mechanisms while achieving the same separation efficiency through temperature-driven adsorption-desorption cycles.
4Quantity of substance
If thermal swing adsorption with external heat application is used, then CO2 can be desorbed, but energy requirements increase
Solution Approach 1:
The system uses free temperature swing between day and night environmental temperatures to drive the adsorption-desorption cycles. During the day, higher temperatures promote desorption of CO2 from the adsorbent, while nighttime cooling enables adsorption, eliminating the need for external heating or cooling energy inputs and significantly reducing energy 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 approach reduces energy requirements and costs by achieving efficient CO2 capture and regeneration without external heat application, maintaining system efficiency through steam recycling and minimizing pressure drop, making CO2 capture from flue gases more economical.
Implementation Method 1
adsorbing CO2 from a feed stream on a feed stream
Implementation Method 2
desorbing CO2 by concentration swing adsorption and displacement desorption of the CO2 on the sorbent by water
Data Source
AI summary
A circulating moving bed and process for separating a carbon dioxide from a gas stream is disclosed. The circulating moving bed can include an adsorption reactor and a desorption reactor, and a sorbent that moves through the two reactors. The sorbent can enter the adsorptive reactor and one end and move to an exit point distal to its entry point, while a CO2 feed stream can enter near the distal point and move countercurrently through the sorbent to exit at a position near the entry point of the sorbent. The sorbent can adsorb the CO2 by concentration swing adsorption and adsorptive displacement. The sorbent can then transfer to a regeneration reactor and can move countercurrently against a flow of steam through the regeneration reactor. The sorbent can be regenerated and the carbon dioxide recaptured by desorbing the carbon dioxide from the sorbent using concentration swing desorption and desorptive displacement with steam.