Acid Gas Absorbent Composition That Prevents Solid Formation
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Solution Overview
Problem
Existing acid gas capture technologies using carboxylate salts face issues such as solid formation during absorption, leading to operational inconveniences and increased energy consumption for regeneration, particularly with alkanolamines and carboxylate-based ionic liquids.
Innovation Solution
A compound with a structure represented by Formula (I), where R1 is an alkyl group with ≥5 carbon atoms, M is protonated organic amine or nitrogen-containing heterocyclic groups, and n is 1-4, is used to create a weak acid weak base salt absorbent by mixing carboxylic acid with organic weak bases, avoiding solid formation and enhancing absorption rates under higher water content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carboxylate salts with quaternary ammonium or phosphonium ions are used to improve CO2 absorption rate, then the absorption rate increases, but solids form during the absorption process making separation inconvenient
Solution Approach 1:
The patent changes the chemical composition parameters by using specific carboxylate salts (potassium, sodium, or ammonium carboxylates) instead of quaternary ammonium or phosphonium salts. This parameter change maintains high absorption rates while preventing solid formation, thus resolving the contradiction between absorption rate and separation convenience
Solution Approach 2:
The patent employs readily available carboxylate salts that are easier to handle and separate compared to quaternary ammonium or phosphonium salts. These materials can be easily regenerated and reused, effectively addressing the operational convenience issue while maintaining absorption performance
2Force
If water concentration is increased to reduce viscosity of carboxylate-based absorbents, then viscosity decreases, but acid gas absorption rate decreases
Solution Approach 1:
The patent optimizes the water content parameter within a specific range (10-30 wt%) to achieve the right balance between viscosity and absorption rate. This precise parameter control allows the system to maintain low viscosity while preserving high absorption performance, resolving the contradiction between these two parameters
3Quantity of substance
If alkanolamines are used for acid gas absorption, then absorption is achieved, but high reaction heat and high regeneration temperatures (105-120°C) result in high energy consumption
Solution Approach 1:
The patent changes the chemical nature of the absorbent from alkanolamines to carboxylate salts, which fundamentally alters the absorption mechanism from strong chemical reaction to weaker interaction. This parameter change enables regeneration at lower temperatures (below 105°C), significantly reducing energy consumption while maintaining absorption capacity
Solution Approach 2:
The patent converts the weakness of carboxylate salts (weaker basicity and smaller interaction force with acid gases) into an advantage. This weaker interaction, which initially seemed detrimental to absorption capacity, actually enables easier and more energy-efficient regeneration, thus converting a potential disadvantage into a beneficial feature
Data Source
Figure 1
AI summary
The present application relates to the field of the absorption and regeneration of acid gases, and specifically relates to an absorbent for capturing acid gases, and a preparation method therefor and the use thereof. A compound for capturing acid gases provided by the present application has a structure as represented by formula (I), wherein R1 is an alkyl group having five or more carbon atoms, M is at least one of a proton-bound organic amine group and a proton-bound heterocyclic group containing a nitrogen atom, and n is an integer from 1 to 4. The compound for capturing acid gases provided by the present application has a relatively weak alkalinity and a relatively small acting force towards acid gases; moreover, the generation of a solid can be avoided during the absorption of acid gases with the compound, and therefore difficulties in the regeneration of the acid gases are reduced, and the regeneration process is relatively easy. The compound provided by the present application has a higher absorption rate for acid gases in the case of a relatively high water content.