3-(Alkylamino)propionitrile CO2 Absorbent Low Regeneration Energy
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Solution Overview
Problem
Existing carbon dioxide absorbents face issues with high regeneration temperatures, energy consumption, corrosion, and low CO2 absorption rates, particularly due to the formation of carbamates and bicarbonates, which are thermally stable and require high energy for regeneration.
Innovation Solution
A carbon dioxide absorbent based on a 3-(alkylamino)propionitrile compound, combined with a secondary alkanolamine, which reduces the thermal stability of carbamate compounds and facilitates regeneration at lower temperatures, thereby reducing energy consumption and maintaining absorption capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If amine-based aqueous solvents are used to absorb carbon dioxide, then high carbon dioxide absorption capacity is achieved, but high regeneration temperature (120°C or higher) is required causing excessive energy consumption
Solution Approach 1:
The invention changes the chemical structure parameter of the absorbent by introducing a nitrile group (-C≡N) to the amine molecule. This structural modification fundamentally alters the reaction mechanism with CO2, forming compounds with lower thermal stability that can be regenerated at temperatures below 100°C, thus reducing energy consumption while maintaining absorption capacity
Solution Approach 2:
The invention creates a composite chemical structure by combining amine functionality with nitrile group. This composite molecular structure (3-(alkylamino)propionitrile) integrates the CO2 reactivity of amines with the thermal instability characteristic of nitriles, achieving both high absorption capacity and low regeneration energy requirements
2Quantity of substance
If high regeneration temperature is applied to separate carbon dioxide from amine absorbent, then carbon dioxide stripping is achieved, but excessive volatile loss of alkanolamine occurs
Solution Approach 1:
By modifying the absorbent's chemical structure to include a nitrile group, the thermal stability of the CO2-absorbent complex is reduced. This allows regeneration to proceed at lower temperatures (below 100°C), preventing the thermal volatilization and decomposition of the alkanolamine components that occur at conventional high regeneration temperatures
3Use of energy by moving object
If physical absorption using organic solvents is used to reduce energy consumption, then lower regeneration energy is required, but carbon dioxide absorption capacity is significantly lower than aqueous amine solutions
Solution Approach 1:
The invention creates a hybrid absorption mechanism by combining chemical reactivity (like amine-based systems) with reduced thermal stability (like physical absorbents). The nitrile-modified amine forms reversible complexes with CO2 that are easier to regenerate than traditional carbamates, achieving both adequate absorption capacity and lower regeneration energy
Solution Approach 2:
The chemical structure modification changes the thermodynamic parameters of the absorption reaction, reducing the bond strength between the absorbent and CO2. This allows the system to achieve good absorption capacity at lower temperatures and pressures while requiring minimal energy for regeneration, bridging the gap between chemical and physical absorption methods
4Quantity of substance
If amine compounds react with carbon dioxide to form carbamate compounds, then high absorption capacity is achieved, but irreversible formation and decomposition due to impurities causes corrosion of absorption device
Solution Approach 1:
The introduction of the nitrile group changes the chemical reactivity parameters of the amine, forming a different type of complex with CO2 that is less prone to irreversible degradation. This modified reaction pathway reduces the formation of corrosive byproducts from impurity reactions, protecting the absorption device while maintaining high CO2 capacity
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 absorbent achieves high CO2 absorption rates with significantly reduced regeneration temperatures, minimizing energy consumption and maintaining initial absorption capability even after repeated cycles.
Implementation Method 1
when reacting with carbon dioxide, an alkanolamine absorbent is chemically combined to thereby form carbamate compounds
Implementation Method 2
when heat is applied to the alkanolamine absorbent, the carbamate compounds are separated such that the carbon dioxide can be stripped and recovered
Data Source
AI summary
The present invention relates to a method for using, as a carbon dioxide absorbent, a secondary amine having a nitrile group, that is, a 3-(alkylamino)propionitrile compound. The absorbent based on the 3-(alkylamino)propionitrile compound and the carbon dioxide absorption method and separation method using same, according to the present invention, not only have an excellent carbon dioxide absorption capacity and a rapid carbon dioxide absorption rate, but also allow absorbent regeneration even at a considerably low temperature compared with a conventional alkanolamine-based absorbent and thus can significantly reduce the entire energy consumption required for an absorption process, and can also prevent recovered carbon dioxide from being contaminated with moisture and absorbent vapor, owing to the low regeneration temperature.