Isopropyl Alcohol Separation Train for Propylene Recovery
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Solution Overview
Problem
Conventional isopropyl alcohol preparation processes suffer from reduced propylene conversion rate and selectivity due to the inclusion of isopropyl alcohol in recovered unreacted propylene monomer, leading to reverse reactions and loss of propylene monomer, while inert gas accumulation hampers the process efficiency.
Innovation Solution
A method involving an absorption column, first and second gas purification columns, and an inert gas removal column is employed to separate isopropyl alcohol and unreacted propylene monomer, with pre-separation using flash drums to control stream composition and prevent isopropyl alcohol inclusion, promoting forward reactions and reducing propylene loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional separation process is used to recover unreacted propylene monomer, then propylene monomer can be reused, but isopropyl alcohol contaminates the recovered stream causing reverse reactions and reduced conversion rate
Solution Approach 1:
The separation process is divided into multiple sequential stages: absorption column for initial separation, flash drum for rapid equilibrium separation, and distillation column for final purification. Each stage targets specific components at different concentrations, progressively improving the purity of recovered propylene monomer while maintaining high conversion rate.
Solution Approach 2:
A solvent system is introduced as an intermediary medium in the absorption column to selectively absorb isopropyl alcohol from the reaction mixture. This intermediary enables separation of propylene monomer and isopropyl alcohol based on differential solubility, preventing alcohol contamination in the recovered monomer stream.
2Loss of substance
If multiple purification columns are added to improve separation efficiency, then propylene loss is reduced, but device complexity increases
Solution Approach 1:
The flash drum is integrated into the separation train between the absorption column and distillation column, combining rapid equilibrium separation with gradual purification. This merged approach efficiently removes bulk isopropyl alcohol before distillation, reducing propylene loss while avoiding the need for additional complex equipment.
Solution Approach 2:
The flash drum performs preliminary separation of isopropyl alcohol from propylene monomer before the mixture enters the distillation column. This preliminary action removes the majority of contaminating alcohol, allowing the distillation column to focus on final trace removal and thereby minimizing propylene loss with optimized device configuration.
3Productivity
If inert gas is not removed from propylene monomer stream, then process is simpler, but inert gas accumulates and hampers process efficiency
Solution Approach 1:
The distillation column operates to separate and concentrate inert gases in the overhead stream, which is then partially purged from the system. This self-service mechanism allows the process to automatically manage inert gas accumulation through the natural separation properties of the distillation unit, maintaining process efficiency without requiring separate inert gas removal equipment.
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
Enhances separation efficiency, prevents isopropyl alcohol from contaminating the unreacted propylene monomer, promotes forward reactions, and minimizes propylene loss by effectively recycling the unreacted propylene, thereby increasing isopropyl alcohol production and reducing inert gas accumulation.
Implementation Method 1
supplying a reaction product stream formed by reacting a propylene monomer and water in a reactor to an absorption column
Implementation Method 2
pre-separation using flash drums to control stream composition
Implementation Method 3
supplying a lower discharge stream including isopropyl alcohol from the absorption column to a first gas purification column, supplying a part of an upper discharge stream including an unreacted propylene monomer from the absorption column to a second gas purification column
Data Source
AI summary
A method of preparing isopropyl alcohol, where a propylene monomer and water are reacted in a reactor to produce a reaction product including isopropyl alcohol, and the reaction product stream is separated into unreacted propylene monomer and isopropyl alcohol with high purity using an absorption column, a first gas purification column, a second gas purification column, and an inert gas removal column.