Isopropyl Alcohol Purification With Propylene Liquefaction Recycle

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Solution Overview

Problem

The existing isopropyl alcohol preparation process faces challenges in efficiently recycling unreacted propylene monomer due to high energy consumption and operational difficulties in compressing the vapor phase stream, leading to increased facility maintenance and energy costs.

Innovation Solution

A method involving a liquefaction process using heat exchangers to convert the vapor phase stream from the absorption column to a liquid phase, reducing the volumetric flow rate and enabling efficient circulation of unreacted propylene monomer back to the reactor, with heat recovery and reduced refrigerant use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the vapor phase stream is compressed to high pressure through a compressor, then the stream can be recycled to the reactor, but energy consumption increases and facility maintenance costs increase

Engineering Contradiction:
Improverecycling capabilityVSAvoidenergy consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent applies phase transition by condensing the vapor phase stream from the absorption column into a liquid phase stream. This phase change from vapor to liquid dramatically reduces the volumetric flow rate, allowing the stream to be recycled to the reactor through liquid piping without requiring high-pressure compression, thereby eliminating the energy-consuming compressor while maintaining recycling capability

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The patent changes the physical state parameter of the stream from vapor phase to liquid phase through condensation. This parameter change fundamentally alters the flow characteristics, enabling the stream to be transported and recycled through standard liquid piping systems without the need for high-pressure compression equipment, thus reducing energy consumption and maintenance costs

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the vapor phase stream is compressed to high pressure, then the stream can be transferred, but the compression process is difficult to operate and maintain

Engineering Contradiction:
Improvetransfer capabilityVSAvoidcompression process complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent employs phase transition from vapor to liquid through condensation, which simplifies the transfer process. The liquid phase stream can be easily pumped and transported through standard piping infrastructure, eliminating the need for complex high-pressure compression equipment and associated operational and maintenance challenges

Inventive Principle:
Principle #36Phase transitions

3Ease of operation

If a large diameter pipe is used to handle the vapor phase stream, then the stream can be transported, but the facility maintenance costs increase

Engineering Contradiction:
Improvetransport capabilityVSAvoidfacility maintenance costs
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent utilizes phase transition from vapor to liquid phase, which reduces the volumetric flow rate by a factor of approximately 1000 times. This dramatic volume reduction allows the use of standard-sized liquid piping instead of large-diameter vapor piping, significantly reducing material costs, installation complexity, and ongoing maintenance requirements

Inventive Principle:
Principle #36Phase transitions

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 enhances the circulation efficiency of unreacted monomer, reduces energy consumption, and decreases facility maintenance costs by simplifying the compression process.

Implementation Method 1

a liquefaction process when recovering an unreacted product in separating isopropyl alcohol from a reaction product

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

A method involving a liquefaction process using heat exchangers to convert the vapor phase stream from the absorption column to a liquid phase

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4692036A1Method for preparing isopropyl alcohol
Publication Date: 2026.02.11 LG CHEM LTD
  • EP4692036A1 patent drawingFigure 1
  • EP4692036A1 patent drawingFigure 2
  • EP4692036A1 patent drawingFigure 3

AI summary

The present invention relates to a method of preparing isopropyl alcohol, the method including: supplying a feed stream including a propylene monomer and water to a reaction unit and allowing a reaction to proceed to produce a reaction product including isopropyl alcohol, a propylene monomer, and water; supplying each of a first stream including a vapor phase reaction product and a second stream including a liquid phase reaction product that are discharged from the reaction unit to an absorption column of a purification unit; and discharging a third vapor phase stream including the propylene monomer through an upper portion of the absorption column to be circulated to the reaction unit, and discharging a fourth liquid phase stream including water and isopropyl alcohol through a lower portion of the absorption column to be fed to an isopropyl alcohol purification unit, wherein the purification unit includes one or more heat exchangers, and when the third stream is circulated to the reaction unit, the third stream is converted from a vapor phase to a liquid phase through the one or more heat exchangers provided in the purification unit, and then transferred.