Fatty Acid Distillation Column Pressure Window for High-Purity Separation

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Solution Overview

Problem

Existing methods for separating polyunsaturated fatty acids and fatty acid esters are inefficient due to their high temperature sensitivity, leading to decomposition or isomerization, especially in distillation processes with short-path distillation.

Innovation Solution

A distillation process with a pressure drop between the column head and bottom of ≥ 3.3 mbar and ≤ 6 mbar is employed, using a distillation apparatus with at least 30 theoretical separation stages, and components like trays or packings, achieving a higher throughput and separation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If short-path distillation is used to separate polyunsaturated fatty acids, then the separation process can be carried out, but decomposition or isomerization occurs due to high temperature sensitivity

Engineering Contradiction:
ImprovethroughputVSAvoiddecomposition or isomerization
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by optimizing the pressure drop across the distillation column to a specific range (≥ 3.3 mbar and ≤ 6 mbar). This parameter optimization allows the system to achieve higher throughput while maintaining temperatures that prevent decomposition or isomerization of polyunsaturated fatty acids. The pressure drop parameter is carefully controlled to balance separation efficiency with thermal sensitivity constraints.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by using a distillation column with at least 10 theoretical separation stages that enables flexible operation. The system can dynamically adjust operating conditions including pressure drop, temperature profiles, and vapor-liquid contact efficiency to match the thermal sensitivity requirements of different polyunsaturated fatty acid mixtures while maintaining high productivity.

Inventive Principle:
Principle #15Dynamics

2Productivity

If distillation with larger pressure drop is used to increase throughput, then productivity improves, but temperature increases causing decomposition or isomerization

Engineering Contradiction:
ImprovethroughputVSAvoiddistillation temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent resolves this contradiction by changing the pressure drop parameter to an optimal range (≥ 3.3 mbar and ≤ 6 mbar) that decouples the relationship between throughput and temperature. Within this pressure drop window, the system achieves high productivity while maintaining temperatures below the decomposition threshold of polyunsaturated fatty acids, breaking the conventional trade-off between these two parameters.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The continuous distillation process with optimized pressure drop maintains steady-state operation that continuously separates fatty acids at high throughput without temperature excursions. The consistent pressure drop control ensures continuous operation at optimal temperature conditions, preventing the temperature spikes that would cause decomposition while sustaining high productivity levels.

Inventive Principle:
Principle #20Continuity of useful action

3Temperature

If short-path distillation with thin film evaporator is used, then temperature can be controlled, but separation efficiency is relatively low

Engineering Contradiction:
Improvedistillation temperature controlVSAvoidseparation efficiency
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing the separation process into multiple theoretical stages (at least 10 stages) within the distillation column. This segmentation of the separation function across multiple stages enables high separation efficiency while maintaining controlled temperatures, overcoming the limitation of single-stage short-path distillation that achieves low separation efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from the single-dimension approach of short-path distillation (single evaporation surface) to a multi-dimensional separation process using a column with multiple theoretical stages. This dimensional expansion in the separation process allows simultaneous achievement of temperature control and high separation efficiency by distributing the separation function across multiple vapor-liquid equilibrium stages.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 process effectively separates polyunsaturated fatty acids without decomposition or isomerization, achieving high purity and yield, particularly suitable for omega-3 and omega-6 fatty acids, with optional urea precipitation and short-path distillation for further enrichment.

Implementation Method 1

a rising vapor of the liquid mixture in a column of a distillation apparatus having at least 10 theoretical separation stages is brought into contact with descending condensate formed from the vapor, wherein mass and/or heat exchange takes place on internals of the column between the vapor and the condensate

Methodology Applied
Scientific EffectDistillation: Distillation

Implementation Method 2

mass and/or heat exchange takes place on internals of the column between the vapor and the condensate

Methodology Applied
Scientific EffectVapor-liquid mass exchange:

Implementation Method 3

mass and/or heat exchange takes place on internals of the column between the vapor and the condensate

Methodology Applied
Scientific EffectVapor-liquid heat exchange: Heat Exchanger

Implementation Method 4

a thin film of liquid mixture, formed (possibly by wiping) on a heated evaporator surface, is partially evaporated onto a nearby condenser of a short-path distillation apparatus

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 5

a thin film of liquid mixture, formed (possibly by wiping) on a heated evaporator surface, is partially evaporated onto a nearby condenser

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3319701B1Process for obtaining free unsaturated fatty acid and/or fatty acid ester
Publication Date: 2026.04.15 K D PHARMA BEXBACH GMBH
  • EP3319701B1 patent drawingFigure 1

AI summary

The invention relates to a process for obtaining free fatty acid and/or free fatty acid ester, in which a liquid mixture containing the free fatty acid and/or the fatty acid ester is separated by contacting a vapour of the liquid mixture in a column of a distillation apparatus with condensate formed from the vapour running downward, wherein heat and mass transfer takes place between the vapour and the condensate on column internals. According to the invention, the column has at least 10 theoretical plates and the separation is conducted with a pressure drop between the top and bottom of the column Δp of ≥ 3.3 mbar. Appropriately, the liquid mixture, preferably produced from vegetable oil or from fish oil, contains polyunsaturated fatty acid, preferably omega-6 or omega-3 fatty acid and/or alkyl monoesters and/or glycerol monoesters. In one configuration of the invention, the column has at least 30, preferably at least 40, theoretical plates and the separation is conducted with a pressure drop Δp between 3.5 mbar and 6 mbar.