Two-Column Distillation for Low Boiling Point Separation

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Solution Overview

Problem

Current distillation processes face challenges in efficiently separating and purifying mixtures with components that have small differences in boiling points, leading to high energy consumption and instability in operation.

Innovation Solution

The method involves a two-column distillation process where the first column operates at a higher pressure than the second, with a specific reflux ratio and heat exchange configuration to maximize energy efficiency and stability, allowing for the reuse of heat and condensation to optimize separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional distillation process is used for separating components with small boiling point difference, then separation can be achieved, but energy consumption increases and operation stability deteriorates

Engineering Contradiction:
Improveenergy consumptionVSAvoidoperation stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent changes the operating parameters of the distillation columns, specifically setting the first column to operate at higher pressure (e.g., 10-20 atm) than the second column (e.g., 1-5 atm). This pressure differential creates a temperature difference that enhances the separation efficiency for components with small boiling point differences while reducing overall energy consumption and improving operation stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent divides the separation process into two distinct distillation columns with different operating pressures and functions. The first column performs initial separation at high pressure, and the second column performs further purification at lower pressure. This segmentation allows each column to be optimized for its specific separation task, improving overall efficiency and stability

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If distillation column separation is applied to components with boiling point difference within 15°C, then separation is attempted, but additional process energy is required and operation stability is inhibited

Engineering Contradiction:
Improveseparation efficiencyVSAvoidprocess energy
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

By changing the pressure parameter between the two distillation columns, the patent creates a temperature gradient that amplifies the separation effect. The high-pressure first column operates at higher temperature, while the low-pressure second column operates at lower temperature, creating a natural heat flow that reduces external energy requirements while maintaining high separation precision for components with boiling point differences of 15°C or less

Inventive Principle:
Principle #35Parameter changes

3Productivity

If conventional single-column distillation is used, then process is simple, but energy consumption is high and purification efficiency is limited

Engineering Contradiction:
Improvepurification efficiencyVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent employs two distillation columns with different operating pressures to perform sequential separation tasks. The first high-pressure column handles the bulk separation, and the second low-pressure column performs final purification. This segmented approach achieves higher overall purification efficiency while the heat integration between columns reduces total energy consumption

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines heat exchangers with the distillation columns to integrate heat recovery functions. The heat exchangers recover heat from the overhead vapor of one column and use it to preheat the feed or reboiler of another column, merging the separation and heat recovery functions into a unified system that improves productivity while reducing energy loss

Inventive Principle:
Principle #5Merging (Combining)

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 results in a 30% or more energy savings while ensuring high purity and yield of the desired product, maintaining operation stability even with small boiling point differences.

Implementation Method 1

a first distillation column (a heavy end cut column), heavy components are separated in a lower portion, and a product to be collected and light components are collected in an upper portion

Methodology Applied
Scientific EffectDistillation: Distillation

Implementation Method 2

The collected product and the light components are sent again to a second distillation column (a light end cut column), and the light components are separated in the upper portion and the product is produced in the lower portion

Methodology Applied
Scientific EffectDistillation: Distillation

Data Source

PatentEP3639903B1Method for separating and purifying mixture having small difference in boiling points
Publication Date: 2023.10.04 LG CHEM LTD
  • EP3639903B1 patent drawingFigure 1
  • EP3639903B1 patent drawingFigure 2
  • EP3639903B1 patent drawingFigure 3~4

AI summary

Provided is a method of separating and purifying a mixture of components having small difference in boiling point, and the method may maximize an energy collecting amount and collect a product to be desired in high purity and high yield.