Ion Exchange Resin Regeneration Using Acidic Overhead Reflux

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Solution Overview

Problem

Amine treater processes face issues with dilution and large water volumes required for ion exchange resin regeneration, leading to amine solvent loss and concentration dilution in acid gas capture processes due to the need for water washing during the regeneration of heat stable salts.

Innovation Solution

Integrating the operation of the amine treater with the ion exchange process by using an acidic overhead reflux stream to wash and recycle the amine solvent from the ion exchange column, reducing amine dilution and water usage, and utilizing this reflux stream to regenerate the ion exchange resin without adding makeup water.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If water washing is used to displace and wash amine solvent from the ion exchange column prior to resin regeneration, then amine solvent can be recovered and returned to the acid gas capture process, but this introduces water to the amine solvent thereby diluting the concentration of the amine solvent

Engineering Contradiction:
Improveamine solvent lossVSAvoidamine solvent concentration
Core Design Contradiction:
Loss of substanceVSQuantity of substance

Solution Approach 1:

An acidic overhead reflux stream is introduced as an intermediary washing medium between water and the amine solvent. This reflux stream, which is already present in the acid gas capture process, serves as a mediator to displace and wash the amine solvent from the ion exchange column without introducing additional water that would dilute the amine concentration. The reflux stream accomplishes the washing function while maintaining process concentration integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The acidic overhead reflux stream, which is a byproduct of the steam stripping operation in the acid gas capture process, is utilized to perform the washing function. Instead of introducing external water for washing purposes, the process uses its own internal reflux stream to accomplish the amine displacement and washing task, thereby avoiding dilution and eliminating the need for additional water addition.

Inventive Principle:
Principle #25Self-service

2Loss of substance

If large volumes of water are used to wash and displace amine solvent from the ion exchange column, then amine solvent recovery is improved, but water volume requirements and waste treatment loads increase

Engineering Contradiction:
Improveamine solvent recoveryVSAvoidwater volume
Core Design Contradiction:
Loss of substanceVSQuantity of substance

Solution Approach 1:

The acidic overhead reflux stream serves as an intermediary washing medium that replaces large volumes of water. This reflux stream, being a byproduct of the steam stripping operation, is already available in the process and can effectively displace and wash the amine solvent from the ion exchange column without requiring additional water inputs, thereby reducing overall water volume requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The acidic overhead reflux stream, which would otherwise be discarded or require separate treatment, is recovered and put to useful purpose by utilizing it as the washing medium for the ion exchange column. This transforms a waste stream into a valuable process resource, improving amine solvent recovery while avoiding the need for additional water and reducing waste treatment loads.

Inventive Principle:
Principle #34Discarding and recovering

3Reliability

If the ion exchange resin is regenerated frequently to maintain anion removal capacity, then heat stable salt removal efficiency is improved, but process downtime and operational complexity increase

Engineering Contradiction:
Improveanion removal capacityVSAvoidregeneration process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The regeneration process is merged with the existing steam stripping operation by utilizing the acidic overhead reflux stream from steam stripping as the washing medium for ion exchange resin regeneration. This consolidation eliminates the need for separate water washing systems and integrates the regeneration function into the existing process flow, thereby reducing operational complexity while maintaining reliable anion removal capacity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The acidic overhead reflux stream serves multiple functions: it acts as the washing medium for displacing amine solvent from the ion exchange column, provides the regeneration agent for restoring resin capacity, and maintains process concentration integrity. This multi-functionality reduces the number of separate processes needed, simplifying overall operation while ensuring reliable heat stable salt removal.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 minimizes amine dilution and water volume requirements, allowing for efficient amine recovery and recycling, maintaining the amine solvent concentration in the acid gas capture process and reducing waste treatment loads.

Implementation Method 1

utilizing this reflux stream to regenerate the ion exchange resin

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Implementation Method 2

The separation of acid gases such as sulfur dioxide, hydrogen sulfide or carbon dioxide from gas streams such as flue gas or hydrocarbon containing streams by means of absorption into aqueous amine solvents is well known

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP2004308B1Regeneration of ion exchangers that are used for salt removal from acid gas capture plants
Publication Date: 2014.09.03 CANSOLV TECH INC
  • EP2004308B1 patent drawingFigure 1
  • EP2004308B1 patent drawingFigure 2
  • EP2004308B1 patent drawingFigure 3

AI summary

A method for the removal of an amine captureable gas from a feed gas stream using an amine solvent, the method comprises (a) contacting the feed gas stream with a lean amine solvent to form a rich amine solvent, wherein heat stable salts are present in the rich amine solvent; (b) stripping amine captureable gas from the rich amine solvent to form the lean amine solvent and an overhead reflux stream; (c) periodically contacting at least a portion of one or both of the lean amine solvent and the rich amine solvent with an anion exchange resin to form a first heat stable salt lean amine solvent; (d) periodically regenerating the anion exchange resin, wherein during the regeneration of the anion exchange resin, at least a portion of the reflux stream is used to wash the amine solvent from the anion exchange resin to produce a second heat stable salt lean amine solvent; and, (e) recycling at least a portion of the first and the second heat stable salt lean amine solvent for use in capturing the amine captureable gas from the feed gas.