Multistage Liquid-Liquid Extractor Heavy Phase Recycle for Rag Layer Control

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Solution Overview

Problem

The recovery of diphosphonite-containing compounds from mixtures involving diphosphonite-containing compounds, organic mononitriles, and organic dinitriles in liquid-liquid extraction processes is hindered by the formation of emulsion phases and rag layers, which impede phase separation and reduce extraction efficiency in multistage countercurrent liquid-liquid extractors.

Innovation Solution

A multistage countercurrent liquid-liquid extraction process where a portion of the heavy phase is recycled back to the settling section of the first stage, enhancing settling and reducing emulsion phase size and rag layer formation, thereby improving the separation and extraction efficiency of diphosphonite-containing compounds into the light phase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If liquid-liquid extraction is performed in a multistage countercurrent extractor, then extraction efficiency is improved, but emulsion phase formation and rag layer accumulation occur which impede phase separation

Engineering Contradiction:
Improveextraction efficiencyVSAvoidphase separation
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent extracts and removes the harmful rag layer from the liquid-liquid extraction system by introducing a solid adsorbent material that selectively adsorbs the rag layer components. This allows the rag layer to be separated and removed from the extraction system, preventing accumulation and maintaining reliable phase separation while preserving extraction efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a solid adsorbent material as an intermediary substance that mediates between the emulsion phase and the rag layer. The adsorbent material interacts with the rag layer components, facilitating their separation from the liquid phases and enabling continuous operation without shutdowns for rag layer removal.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If continuous operation is maintained to improve productivity, then output increases, but rag layer accumulation eventually halts phase separation requiring shutdown

Engineering Contradiction:
Improvecontinuous operationVSAvoidprocess continuity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent enables continuous operation of the liquid-liquid extraction system by continuously introducing solid adsorbent material that prevents rag layer accumulation. The adsorbent material continuously adsorbs rag layer components as they form, maintaining uninterrupted phase separation and allowing the extraction process to operate continuously without shutdowns.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent implements a feedback mechanism where the solid adsorbent material responds to the formation of rag layer by adsorbing it as it accumulates. This feedback action prevents rag layer buildup from reaching levels that would halt phase separation, maintaining process continuity and allowing uninterrupted extraction operation.

Inventive Principle:
Principle #23Feedback

3Productivity

If extraction solvent contacts feed mixture for extended periods to improve extraction, then extraction efficiency increases, but interfacial rag layer forms and halts phase separation

Engineering Contradiction:
Improveextraction efficiencyVSAvoidphase separation time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by introducing solid adsorbent material at the beginning of the extraction process or at the point where rag layer formation begins. The adsorbent material proactively adsorbs rag layer components before they can accumulate to form a halting interfacial layer, allowing extended extraction contact time without sacrificing phase separation.

Inventive Principle:
Principle #10Preliminary action

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 recycling of the heavy phase leads to increased settling rates, reduced emulsion phase size, and enhanced recovery of diphosphonite-containing compounds, minimizing rag layer formation and maintaining process continuity by preventing shutdowns due to rag accumulation.

Implementation Method 1

contacting the feed mixture with extraction solvent in the multistage countercurrent liquid-liquid extractor; wherein the light phase comprises extraction solvent and extracted diphosphonite-containing compounds

Methodology Applied
Scientific EffectLiquid-liquid extraction: Liquid-Liquid Extraction

Implementation Method 2

a light phase separates from a heavy phase in the settling section; wherein the light phase comprises extraction solvent and extracted diphosphonite-containing compounds, wherein the heavy phase comprises organic mononitriles and organic dinitriles

Methodology Applied
Scientific EffectDensity-based phase separation: Density Gradient

Implementation Method 3

recycling the heavy phase leads to increased settling rates, reduced emulsion phase size, and enhanced recovery of diphosphonite-containing compounds

Methodology Applied
Scientific EffectSettling: Settling

Data Source

PatentEP3010615B1Process for the recovery of diphosphonite containing compounds using multistage countercurrent liquid-liquid extractor with mixer-settler and heavy phase recycle
Publication Date: 2022.09.28 INVISTA TEXTILES (U K) LTD
  • EP3010615B1 patent drawingFigure 1~3
  • EP3010615B1 patent drawingFigure 4~5
  • EP3010615B1 patent drawing

AI summary

Disclosed herein are methods for recovering diphosphonite-containing compounds from mixtures comprising organic mononitriles and organic dinitriles, using liquid-liquid extraction. Also disclosed are treatments to enhance extractability of the diphosphonite-containing compounds.