Amine Absorbent HSS Removal via Residual CO2 Flashing

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Solution Overview

Problem

In carbon dioxide capture processes using amine absorbents, heat stable salts (HSS) accumulate due to degradation, reducing the absorbent's CO2 removal potency and causing significant amine losses during separation processes like electrodialysis, leading to economic disadvantages.

Innovation Solution

Implementing a flashing and optional stripping step to remove residual CO2 from the amine absorbent before subjecting it to reclamation, utilizing a flash drum and stripper to reduce CO2 levels, thereby minimizing amine losses and maintaining the absorbent's integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrodialysis or ion exchange is used to separate HSS from amine absorbent, then HSS removal is achieved, but significant amine losses occur when CO2 loading is high

Engineering Contradiction:
ImproveHSS removal effectivenessVSAvoidamine losses
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by performing flashing and/or stripping to remove CO2 from the amine absorbent before feeding it to the reclamation unit. This pre-treatment step reduces CO2 loading in the lean solvent, which subsequently minimizes amine losses during the electrodialysis or ion exchange separation process while maintaining effective HSS removal

Inventive Principle:
Principle #10Preliminary action

2Loss of substance

If flashing and stripping steps are added to remove residual CO2, then amine losses are reduced, but additional equipment and operational complexity are required

Engineering Contradiction:
Improveamine lossesVSAvoidsystem complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The patent applies self-service by utilizing the existing temperature and pressure conditions from the CO2 capture process itself to perform flashing and stripping. The lean solvent leaving the stripper is already at elevated temperature and reduced pressure, conditions that naturally favor CO2 removal without requiring additional external energy input or complex equipment, thus minimizing amine losses while avoiding excessive system complexity

Inventive Principle:
Principle #25Self-service

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

This method effectively reduces amine losses by 75-80% and maintains the absorbent's effectiveness, providing an economic advantage by minimizing additional energy requirements and preventing further degradation.

Implementation Method 1

The flashing (and optionally stripping) step comprises flashing the withdrawn slipstream of regenerated amine absorbent to remove residual CO2

Methodology Applied
Scientific EffectFlashing: Flash Evaporation

Implementation Method 2

Stripping is performed in a stripper, wherein the incoming amine absorbent is heated, e.g. by steam or electricity, to a temperature at which more volatile components, such as CO2 in this case, are at least partly evaporated and leave the stripper via a gas/vapor exit

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2686087B2Method and system for the removal of heat stable amine salts from an amine absorbent
Publication Date: 2023.06.07 GENERAL ELECTRIC TECH GMBH
  • EP2686087B2 patent drawingFigure 1
  • EP2686087B2 patent drawingFigure 2

AI summary

A method and a system for the removal of heat stable amine salts from an amine absorbent used in a carbon dioxide (CO2) capture process, the method comprising: withdrawing amine absorbent containing heat stable amine salts from the CO2 capture process; subjecting the withdrawn amine absorbent containing heat stable amine salts to a residual CO2 removal step (117); subjecting the amine absorbent (120) from the residual CO2 removal step to a separation step (116) to separate heat stable amine salts (124) from the amine absorbent; and returning the amine absorbent (122) having a reduced concentration of heat stable amine salts to the CO2 capture process.