Azeotropic Distillation for Organic Acid Concentration
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Solution Overview
Problem
Conventional distillation methods for removing water from organic acid streams in high-pressure nitration processes are energy-consuming and result in unavoidable acid losses due to low relative volatility between acetic acid and water, especially when multiple organic acids are present, making it economically and energetically inefficient.
Innovation Solution
The process employs a mixed phase reactor system and an azeotropic distillation column using an alkyl acetate as an entrainer to separate water from organic acids, achieving high concentration of organic acids in the bottom stream and recycling the organic phase back to the column to enhance separation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional distillation is used to remove water from organic acid stream, then water removal is achieved, but energy consumption increases and acid losses occur
Solution Approach 1:
An entrainer substance is introduced as an intermediary component that forms a ternary azeotrope with water and organic acid. This entrainer mediates the separation process by creating a new vapor-liquid equilibrium that favors water removal while keeping organic acid in the liquid phase, thus resolving the contradiction between energy efficiency and separation effectiveness
Solution Approach 2:
The invention changes the compositional parameters of the system by adding an entrainer, which alters the relative volatility relationships and azeotropic composition. This parameter change enables selective water removal at lower energy input while maintaining high organic acid recovery, addressing both energy consumption and separation precision concerns
2Loss of substance
If conventional distillation is used, then water is removed, but organic acid losses occur in the overhead stream
Solution Approach 1:
The entrainer acts as a mediator that selectively associates with water in the vapor phase through azeotrope formation, preventing organic acid from co-vaporizing. This intermediary mechanism achieves thorough water removal while minimizing organic acid losses to the overhead stream
Solution Approach 2:
The invention creates local quality differentiation in the vapor phase by forming a specific azeotropic composition enriched in water and entrainer but depleted in organic acid. This localized compositional control ensures water is removed while organic acid remains in the liquid phase, reducing substance loss
3Device complexity
If multiple organic acids are present in the stream, then recycling complexity increases, but water removal becomes more difficult
Solution Approach 1:
The entrainer provides a universal separation mechanism that works effectively for mixed organic acid streams containing multiple different acids. By forming a ternary azeotrope with water that is independent of the specific organic acid composition, the entrainer enables simplified single-stage water removal from complex multi-acid mixtures, reducing recycling process complexity while maintaining separation precision
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 significantly reduces energy consumption, minimizes acid losses, and achieves high recovery of organic acids, making the process more economical and efficient for recycling in high-pressure nitration processes.
Implementation Method 1
using an alkyl acetate as an entrainer in the azeotropic distillation column, such that the first bottom stream is separated into at least a second top stream and a second bottom stream
Implementation Method 2
separating the second top stream in a phase separator into an organic phase and an aqueous phase
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Disclosed are processes and apparatuses for concentrating at least one organic acid using an alkyl acetate as an entrainer. The processes and apparatuses may use the same alkyl acetate as an entrainer to concentrate a mixture of organic acids.