Vinyl Acetate Purification via Adsorbent Bed
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Solution Overview
Problem
The high concentration of acetic acid in unreacted vinyl acetate monomer from the ethylene vinyl acetate polymerization process leads to corrosion in equipment and pipelines, limiting its reuse and increasing production costs due to the need for frequent maintenance and low vinyl acetate conversion.
Innovation Solution
A purification process involving the use of adsorbent agents, such as alumina and molecular sieves, to remove acetic acid and water from the vinyl acetate monomer, which includes preliminary loading with an inert gas and controlled conditions to adsorb and regenerate the beds, allowing for the recycling of purified vinyl acetate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If unreacted vinyl acetate monomer is reused directly after polymerization, then production costs are reduced and vinyl acetate conversion efficiency is improved, but acetic acid concentration increases causing equipment corrosion and limiting reuse
Solution Approach 1:
The patent extracts and removes acetic acid from the unreacted vinyl acetate monomer using adsorbent materials such as molecular sieves, activated carbon, or ion exchange resins. This separation process isolates the harmful acetic acid component from the reusable vinyl acetate, enabling the monomer to be recycled without causing equipment corrosion while maintaining high conversion efficiency.
Solution Approach 2:
The patent introduces adsorbent materials as intermediary substances that selectively bind to acetic acid molecules in the unreacted vinyl acetate stream. These intermediaries (adsorbents) facilitate the removal of acetic acid through adsorption mechanisms, allowing the purified vinyl acetate to be reused in subsequent polymerization cycles without the corrosive effects of acetic acid.
2Object-affected harmful factors
If vinyl acetate purification is performed using traditional distillation methods, then acetic acid removal is achieved, but production time increases and energy consumption rises
Solution Approach 1:
The patent replaces the traditional mechanical distillation system with an adsorption-based purification system. Instead of using heat and phase change mechanisms inherent in distillation, the invention employs adsorbent materials that selectively capture acetic acid through surface adsorption. This substitution dramatically reduces both the time required for purification and the energy consumption, as adsorption occurs at ambient or near-ambient temperatures without requiring prolonged heating cycles.
Solution Approach 2:
The patent utilizes porous adsorbent materials such as molecular sieves and activated carbon to remove acetic acid from vinyl acetate. These porous materials provide large surface areas with selective pore structures that favor the adsorption of acetic acid molecules over vinyl acetate molecules. This approach enables rapid, efficient purification without the time and energy demands of traditional distillation processes.
3Reliability
If frequent equipment maintenance is performed to address corrosion from acetic acid, then equipment reliability is maintained, but production downtime increases and operational costs rise
Solution Approach 1:
The patent implements preliminary purification of unreacted vinyl acetate monomer by removing acetic acid through adsorption before the purified monomer is reused in subsequent polymerization cycles. This preliminary action prevents acetic acid from accumulating in the system and causing equipment corrosion, thereby maintaining equipment reliability and avoiding production downtime associated with frequent maintenance interventions.
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
The process effectively reduces acetic acid and water concentrations to below 200 ppm, enabling the safe reuse of vinyl acetate in polymerization and reducing equipment corrosion, thereby lowering production costs and improving vinyl acetate conversion efficiency.
Implementation Method 1
A purification process involving the use of adsorbent agents, such as alumina and molecular sieves, to remove acetic acid and water from the vinyl acetate monomer
Implementation Method 2
A purification process involving the use of adsorbent agents, such as alumina and molecular sieves, to remove acetic acid and water from the vinyl acetate monomer
Data Source
AI summary
Process for purification of unreacted vinyl acetate monomers comprising the steps of preliminarily loading an adsorbent agent bed with a mixture comprising an inert gas and fresh vinyl acetate; and feeding said adsorbent agent bed with unreacted vinyl acetate monomers to remove acetic acid.