Solid Amine Adsorbent Composition for Stable CO2 Cycling
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Solution Overview
Problem
Current solid amine adsorbents face issues of thermal and chemical deactivation due to the volatilization and irreversible reactions of organic amines, leading to significant decreases in adsorption capacity, which hinder their industrial application.
Innovation Solution
A solid amine adsorbent is prepared by modifying organic amines with aldehydes or ketones and using mild crosslinking agents to convert primary amines to secondary amines, maintaining a high secondary amine proportion and enhancing thermal stability, while employing a specific preparation method to ensure pH neutrality and solvent evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pure CO2 is used as purge gas for desorption reactions at high temperatures, then CO2 enrichment and efficient utilization of organic amines is achieved, but organic amines volatilize from the adsorbent surface due to poor thermal stability, leading to physical deactivation
Solution Approach 1:
The patent modifies the chemical structure of organic amines by converting primary amine groups to secondary amine groups through reaction with aldehydes or ketones. This chemical parameter change fundamentally alters the thermal stability characteristics of the amine, enabling it to withstand high-temperature desorption conditions without volatilization while maintaining CO2 capture capability.
Solution Approach 2:
The patent creates a composite adsorbent system by combining modified organic amines (with improved thermal stability) with appropriate support materials. This composite structure allows the amine component to maintain its CO2 reactivity while the overall system achieves the thermal stability needed for industrial application with pure CO2 purge gas.
2Quantity of substance
If pure CO2 is used as purge gas, then CO2 desorption is difficult due to concentration gradient, resulting in irreversible reactions that generate irreversible compounds and cause chemical deactivation of amine groups
Solution Approach 1:
The patent changes the chemical parameter of the amine from primary to secondary amine through modification with aldehydes or ketones. Secondary amines exhibit different reactivity patterns toward CO2, forming carbamates that are more reversible and less prone to forming stable irreversible bicarbonate species, thereby reducing chemical deactivation during cycling.
3Reliability
If methods are employed to enhance cyclic stability, then amine deactivation is reduced, but adsorption capacity decreases by more than 50% in some cases
Solution Approach 1:
The patent achieves a breakthrough by changing the amine structure parameter (primary to secondary amine) rather than using protective measures that block active sites. This structural modification maintains high CO2 reactivity and adsorption capacity while inherently providing resistance against both physical and chemical deactivation mechanisms, avoiding the capacity loss typical of other stabilization approaches.
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 modified adsorbent maintains high stability and adsorption capacity, retaining over 93% of its performance after 10 cycles, with a secondary amine proportion of 70% or higher, addressing the deactivation issues and meeting industrial demands.
Implementation Method 1
the primary and secondary amine groups on organic amine molecules can react with CO2 in a 2:1 molar ratio to form reversible carbamate or carbamic ester products
Implementation Method 2
Solid amine CO2 adsorption technology is characterized by efficient adsorption
Implementation Method 3
After a thermal desorption reaction, the adsorbed CO2 can be separated, regenerating the primary and secondary amine groups
Data Source
AI summary
The present disclosure a solid amine adsorbent and its preparation method and application. The solid amine adsorbent consists of modified organic amines and a porous nano support, with the proportion of secondary amines in the modified organic amines being 70% or higher. The preparation method of the modified organic amines includes the following steps: S1: Mixing the organic amine and the organic amine modifying agent into an acetonitrile solvent and stirring to achieve uniform mixing; S2: Adding a crosslinking agent to the solution and stirring; S3: Gradually adding acetic acid to the solution during stirring to adjust the pH to neutral, then continuing to stir; S4: Using a rotary evaporator to evaporate the solvent at 90-110° C. until completely removed, resulting in the modified organic amine. The modified solid amine adsorbent produced by the present disclosure maintains high stability during cyclic adsorption and desorption processes while also ensuring excellent capacity.