CO2 Absorption Liquid Composition for Low-Viscosity Regeneration
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Solution Overview
Problem
Existing carbon dioxide capture technologies using monoethanolamine (MEA) suffer from high regeneration energy consumption and high capture costs due to high viscosity, phase separation issues, and foam formation, limiting their scalability.
Innovation Solution
An absorption liquid comprising an absorbent, an activator, and a non-aqueous solvent, with a specific mass ratio and viscosity range, is used to enhance phase separation and reduce viscosity, accompanied by a method involving thermal regeneration and distillation to recycle lean liquid phases, utilizing water vapor as a heat source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional MEA absorbent is used for carbon dioxide capture, then carbon dioxide absorption capacity is achieved, but regenerative energy consumption becomes excessively high (3.7-4.2GJ/tCO2)
Solution Approach 1:
The absorption system is segmented into two distinct phases: a CO2-rich lower phase and a CO2-lean upper phase. This segmentation allows selective thermal regeneration of only the CO2-rich phase, significantly reducing the energy consumption compared to regenerating the entire MEA solution. The phase separation enables targeted processing of the portion containing absorbed CO2.
Solution Approach 2:
The invention changes the physical and chemical parameters of the absorbent system by using a composite formulation with specific components (absorbent, activator, auxiliary agent, non-aqueous solvent) in optimized ratios. The absorbent has pKa 8.5-10 and the liquid phase maintains viscosity 6-50 mPa·s, creating conditions favorable for phase separation and reduced regeneration energy while maintaining absorption capacity.
2Quantity of substance
If absorbent concentration is increased to improve carbon dioxide absorption capacity, then absorption capacity increases, but viscosity increases making the system less efficient
Solution Approach 1:
The invention uses a composite absorption liquid formulation consisting of four components: absorbent (3-amino-1-propanol, diglycolamine, monoethanolamine, or diethanolamine with pKa 8.5-10), activator, auxiliary agent, and non-aqueous solvent. This composite structure achieves optimal balance between absorption capacity and viscosity, with the liquid phase maintaining viscosity between 6-50 mPa·s, preventing excessive thickening while preserving CO2 capture capability.
3Use of energy by moving object
If two-phase composite absorbent is used to reduce regenerative energy consumption, then energy consumption decreases, but viscosity becomes excessively high (>100 mPa·s)
Solution Approach 1:
The invention optimizes the compositional parameters and ratios of the four components in the absorption liquid. By carefully controlling the types and proportions of absorbent, activator, auxiliary agent, and non-aqueous solvent, the system achieves phase separation with reduced viscosity (6-50 mPa·s for liquid phase, 200-600 mPa·s for rich liquid phase), overcoming the excessive viscosity problem of conventional two-phase systems.
Solution Approach 2:
The composite absorption liquid uses specifically selected components with complementary properties. The non-aqueous solvent and auxiliary agent contribute to reducing viscosity while the absorbent-activator complex maintains absorption capacity and phase separation behavior, achieving a balanced formulation that avoids the high viscosity penalty.
4Quantity of substance
If absorbent concentration is increased to improve carbon dioxide absorption capacity, then absorption capacity increases, but foam formation becomes more severe
Solution Approach 1:
The composite absorption liquid formulation includes an auxiliary agent component that suppresses foam formation. The synergistic interaction among the four components (absorbent, activator, auxiliary agent, non-aqueous solvent) creates a system where foam generation is minimized even at optimized absorbent concentrations, eliminating the need for separate foam control measures.
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
The solution achieves low viscosity, efficient phase separation, and reduced energy consumption, resulting in lower regeneration energy costs and improved carbon dioxide capture capacity, while maintaining dynamic equilibrium in the non-aqueous solvent system.
Implementation Method 1
Contacting the CO2-containing gas with an absorption liquid phase to obtain an upper layer liquid phase and a lower layer rich liquid phase absorbed carbon dioxide
Implementation Method 2
Thermally regenerating the rich liquid phase to obtain a first lean liquid phase
Implementation Method 3
Distillating a part of the first lean liquid phase to obtain a second lean liquid phase
Data Source
Figure 1
AI summary
The present invention relates to the technical field of carbon dioxide capture. Disclosed are an absorption liquid for capturing carbon dioxide and the use thereof, and a method for capturing carbon dioxide. The absorption liquid comprises: an absorbent, an activator, an auxiliary agent, and/or a non-aqueous solvent, wherein the absorbent is at least one selected from the group consisting of 3-amino-1-propanol, monoethanolamine and diethanolamine. Compared with a traditional two-phase composite absorbent, the absorption liquid has the significant advantages of a low viscosity, a large carbon dioxide absorption capacity, a low regeneration temperature, etc., and has positive significances in reducing the energy consumption and cost during the flue gas carbon dioxide capture process.