Extractive Distillation for Terpene Separation from Alcohol-Water Mixtures

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Solution Overview

Problem

Existing methods for separating terpenes from aqueous alcohol mixtures, such as steam distillation and phase separation, are inefficient due to the solubilizing effect of alcohol, leading to undesirable terpene accumulation in alcohol cycles, especially in processes like citrus pectin extraction.

Innovation Solution

The method involves using extractive distillation in a heatable distillation column with hot water added to the top region, which increases terpene volatility and separates terpenes from overhead vapors, followed by phase separation, allowing for efficient removal of terpenes while maintaining low alcohol concentrations throughout the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If steam distillation and phase separation are used to separate terpenes from aqueous alcohol mixtures, then the process is simple and familiar, but the separation performance is significantly reduced or completely eliminated due to the solubilizing effect of alcohol

Engineering Contradiction:
Improveprocess simplicityVSAvoidseparation performance
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Water is introduced as an intermediary substance into the distillation column to modify the vapor composition. The water acts as a mediator that reduces the alcohol concentration in the overhead vapors, thereby eliminating the solubilizing effect that prevents effective terpene-water separation in the condenser and phase separator.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The composition parameter of the vapor phase is changed by adding water, which alters the relative concentrations of alcohol, water, and terpenes in the overhead vapors. This parameter change reduces the alcohol concentration below the threshold needed for solubilization, enabling effective phase separation.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If rectification or partial evaporation is used to separate terpenes from alcohol-water mixtures, then the process attempts to address separation, but satisfactory separation cannot be achieved because mixtures show very different behavior depending on composition and physical properties

Engineering Contradiction:
Improveseparation effectivenessVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of attempting complex rectification or partial evaporation processes that must account for varying mixture compositions, the invention changes the key parameter of vapor composition by introducing water. This simplifies the approach while achieving consistent separation effectiveness across different mixture compositions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a simplified version of steam distillation (introducing water at the top rather than from below) that copies the successful separation mechanism while avoiding the complexity of multiple evaporation stages and composition-dependent optimization.

Inventive Principle:
Principle #26Copying

3Productivity

If alcohol is recycled after extraction, then the process is economical and sustainable, but terpenes accumulate in the alcohol cycle due to inadequate separation

Engineering Contradiction:
Improveprocess economyVSAvoidterpene accumulation
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

Water serves as an intermediary that enables effective terpene removal from the alcohol stream, allowing alcohol to be cleanly recycled. The water modifies the vapor composition to ensure complete terpene separation, preventing accumulation in the recycled alcohol.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The phase-separated terpene-poor phase is fed back to the top of the distillation column, creating a feedback loop that continuously maintains low alcohol concentrations in the overhead vapors and ensures complete terpene removal before alcohol recycling.

Inventive Principle:
Principle #23Feedback

4Manufacturing precision

If hot water is added to the top region of the distillation column to reduce alcohol concentration, then terpene volatility increases and separation improves, but the device complexity increases

Engineering Contradiction:
Improveseparation efficiencyVSAvoidcolumn operation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Water is introduced in a predetermined state (hot or boiling) at a specific location (top region) of the distillation column before the vapors reach the condenser. This preliminary action of modifying the vapor composition upstream ensures that the solubilizing effect is eliminated before separation occurs, simplifying the downstream phase separation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The water is introduced at a specific local region (top region of the column) rather than uniformly throughout. This localized introduction creates a specific zone where alcohol concentration is reduced, enabling separation without modifying the entire column operation.

Inventive Principle:
Principle #3Local quality

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 approach effectively separates terpenes from alcohol-water mixtures with high efficiency and reliability, even with varying compositions, and is economically advantageous by utilizing waste heat and recycling low-terpene phases to maintain low alcohol concentrations.

Implementation Method 1

the volatility of a broad spectrum of terpenes is influenced by targeted addition of the entraining agent water into a predetermined area of a distillation column

Methodology Applied
Scientific EffectVolatility: Vapour Pressure

Implementation Method 2

The method proposed according to the invention is therefore based on the principle of extractive distillation (extractive rectification)

Methodology Applied
Scientific EffectExtractive distillation: Distillation

Implementation Method 3

removing the overhead vapors from the distillation column and feeding them to a condenser in which an overhead vapor condensate is produced by condensation

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

Feeding the overhead vapor condensate to a phase separator downstream of the condenser, in which a terpene-rich phase and a terpene-poor phase are separated from the overhead vapor condensate

Methodology Applied
Scientific EffectPhase separation: Density Gradient

Data Source

PatentEP3736030B1Separation of terpenes from alcohol-water mixtures by means of extractive distillation
Publication Date: 2021.08.18 GEA WIEGAND
  • EP3736030B1 patent drawingFigure 1

AI summary

The present invention relates to a process for separating terpenes from an aqueous alcohol mixture, comprising the steps of feeding the terpene-containing aqueous alcohol mixture into a middle section (12a) of a heated distillation column (12); feeding hot water into a top section (12b) of the distillation column (12); removing the top vapors from the distillation column (12) and feeding them to a condenser (20), in which a top vapor condensate is produced by condensation; feeding the top vapor condensate to a phase separator (22) downstream of the condenser (20), in which a terpene-rich phase and a terpene-poor phase are separated from the top vapor condensate; and removing the terpene-rich phase as the final product. The invention further relates to an apparatus for carrying out such a process.