Amine CO2 Separation Composition for Low-Temperature Liquid Stability

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Solution Overview

Problem

Conventional carbon dioxide absorbing solutions containing piperazine precipitate at low temperatures, leading to solidification and issues during transport and storage, particularly in winter conditions.

Innovation Solution

A carbon dioxide separation composition comprising specific amine compounds represented by formulas (1), (2), (3), and (4) or (5), which form carbonates or carbamates, with optimized ratios and concentrations to maintain a low solidification point and enhance liquid state retention, allowing stable storage and transport without the need for strict temperature control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If piperazine is used as an activating agent in carbon dioxide absorbing solution, then carbon dioxide desorption temperature is reduced and energy consumption is lowered, but piperazine precipitates at low temperatures (5-10°C) causing solidification and pumping issues

Engineering Contradiction:

Improveenergy consumption for carbon dioxide recoveryVSAvoidliquid state retention at low temperature

Core Design Contradiction:

Use of energy by stationary objectVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters by introducing specific amine compounds (cyclic secondary amines with 5-7 membered rings containing nitrogen, such as piperidine, homopiperidine, azepane, and their derivatives) in controlled concentrations (0.1-10 mass%) combined with piperazine. This compositional parameter change modifies the freezing point and solubility characteristics of the solution, preventing precipitation while maintaining low-temperature liquid state for reliable transport and storage.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional carbon dioxide absorbing solutions are used, then they maintain liquid state at low temperatures, but they require high temperature (120°C or higher) for carbon dioxide desorption resulting in high energy consumption

Engineering Contradiction:

Improveliquid state retention at low temperatureVSAvoidenergy consumption for carbon dioxide recovery

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent creates a composite amine system combining multiple amine compounds (cyclic secondary amines + piperazine + water) with synergistic effects. The cyclic secondary amine component enables low-temperature desorption while piperazine enhances CO2 absorption capacity, and the specific composition ratios create a solution that remains liquid at low temperatures. This composite material approach resolves both the energy consumption and liquid state retention requirements.

Inventive Principle:

Principle #40Composite materials

3Productivity

If piperazine concentration is increased to improve carbon dioxide absorption capacity, then absorption efficiency is enhanced, but precipitation and solidification occur more readily at low temperatures

Engineering Contradiction:

Improvecarbon dioxide absorption capacityVSAvoidstorage stability at low temperature

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The cyclic secondary amine compounds act as intermediary substances that mediate between piperazine and water, preventing direct precipitation of piperazine at high concentrations and low temperatures. These intermediaries modify the solvation environment, allowing higher piperazine concentrations (up to 60 mass% or more) to remain dissolved without precipitation, thus maintaining both high absorption capacity and storage stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 composition exhibits excellent storage stability and avoids freezing, reducing the risk of container damage and enabling efficient carbon dioxide separation and recovery with reduced energy consumption.

Implementation Method 1

an amine compound (A) represented by the following formula (1) or (2), an amine compound (B) represented by the following formula (3) and carbon dioxide (the amine compound (A) and the amine compound (B) may each independently form a carbonate or a carbamate)

Methodology Applied

Scientific EffectCarbonate formation: Chemical Bonding

Implementation Method 2

Methodology Applied

Scientific EffectCarbamate formation: Chemical Bonding

Data Source

PatentEP4663277A1Amine composition for carbon dioxide separation and method for producing same

Publication Date: 2025.12.17 TOSOH CORP

AI summary

Piperazine-containing aqueous solutions disclosed in prior art documents have a problem such that the entire solutions are solidified under low temperature conditions at degrees of frost e.g. outdoors in winter. A carbon dioxide separation composition, containing an amine compound (A) represented by the following formula (1) or (2), an amine compound (B) represented by the following formula (3) and carbon dioxide (the amine compound (A) and the amine compound (B) may each independently form a carbonate or a carbamate), is used.