Simulated Moving Bed for CO2 Separation
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Solution Overview
Problem
Current CO2 capture technologies from combustion flue gases are inefficient due to low CO2 concentrations and pressures, leading to high energy consumption and costs, particularly in post-combustion CO2 capture, where CO2 is present at low pressures and concentrations, necessitating significant energy for separation and compression.
Innovation Solution
A simulated moving bed system using alkalized sorbents, such as alkalized alumina, that operates at constant temperature and pressure, employing concentration swing adsorption and desorptive displacement with steam to regenerate the sorbent, eliminating the need for pressure or temperature swings and allowing for continuous CO2 capture with reduced energy requirements.
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 due to low CO2 pressure and concentration
Solution Approach 1:
The patent changes the operating parameters from conventional absorption to adsorption process, utilizing solid sorbents with high CO2 selectivity. The system operates at constant temperature and pressure with cyclic pressure variations to achieve CO2 capture at low concentrations without significant energy penalty
Solution Approach 2:
The patent employs cyclic pressure swing adsorption where the system alternates between high-pressure CO2 capture phase and low-pressure sorbent regeneration phase. This periodic operation allows continuous CO2 separation while minimizing energy consumption by regenerating sorbents in situ
2Productivity
If pressure swing adsorption is used for CO2 capture, then CO2 separation efficiency improves, but system complexity and energy requirements increase
Solution Approach 1:
The patent divides the system into multiple fixed sorbent beds that can be operated in sequence through valve switching. Each bed undergoes different stages (CO2 capture, purge, regeneration) in a cyclic manner, enabling continuous operation while simplifying individual bed design and operation
Solution Approach 2:
The patent achieves continuous CO2 capture by having multiple beds operate in different phases of the cyclic process simultaneously. While one bed is capturing CO2, another is being regenerated, ensuring uninterrupted CO2 separation and maintaining high productivity
3Reliability
If temperature swing adsorption is used for sorbent regeneration, then CO2 desorption efficiency improves, but energy consumption increases
Solution Approach 1:
The patent replaces thermal energy input with mechanical pressure variations for sorbent regeneration. By reducing pressure in the regeneration phase, CO2 is desorbed from the sorbent without requiring heat input, significantly reducing energy consumption while maintaining regeneration effectiveness
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 effectively captures CO2 with reduced energy consumption and costs, achieving high CO2 recovery rates while maintaining system efficiency and operational simplicity, suitable for various CO2-rich gas streams including combustion flue gases and natural gas purification.
Implementation Method 1
A simulated moving bed system using alkalized sorbents, such as alkalized alumina, that operates at constant temperature and pressure, employing concentration swing adsorption
Implementation Method 2
employing concentration swing adsorption and desorptive displacement with steam to regenerate the sorbent
Data Source
AI summary
A system and method for separating and/or purification of CO2 gas from a CO2 feed stream is described. The system and method include a plurality of fixed sorbent beds, adsorption zones and desorption zones, where the sorbent beds are connected via valve and lines to create a simulated moving bed system, where the sorbent beds move from one adsorption position to another adsorption position, and then into one regeneration position to another regeneration position, and optionally back to an adsorption position. The system and method operate by concentration swing adsorption/desorption and by adsorptive/desorptive displacement.