MMA Purification Unit with Lateral Extraction
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Solution Overview
Problem
Current MMA purification processes are complex, require multiple steps, and result in significant losses of MMA due to the discharge of azeotropic mixtures with light impurities, while also being prone to polymerization, which complicates achieving ultra-high purity and efficient yield.
Innovation Solution
A simplified purification unit utilizing two distillation columns in series, with a lateral extraction system that recycles the MMA-water azeotropic mixture, minimizing MMA losses and preventing polymerization by controlling temperature and pressure, and incorporating a reflux system to recover MMA from azeotropic mixtures, achieving high purity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional multiple distillation columns are used for MMA purification, then purification thoroughness is improved, but device complexity and process steps increase
Solution Approach 1:
The single complex distillation process is segmented into two simpler distillation columns operating in parallel, each handling different aspects of purification (light impurities and heavy impurities respectively), reducing overall system complexity while maintaining high purity
Solution Approach 2:
The problematic azeotropic mixture discharge step is extracted and replaced with a lateral extraction system that selectively removes light impurities while retaining MMA, eliminating the need for complex multi-column sequences
2Manufacturing precision
If azeotropic mixtures are discharged to remove light impurities, then light impurity removal is improved, but MMA losses increase
Solution Approach 1:
A lateral extraction system acts as an intermediary between the distillation column and the discharge point, selectively extracting light impurities through a side stream while allowing MMA to be recovered and returned to the system, preventing direct loss of MMA with the impurity discharge
Solution Approach 2:
Instead of discarding the entire azeotropic mixture containing both light impurities and MMA, the system recovers MMA from the lateral extraction stream and returns it to the distillation column, discarding only the light impurity portion
3Manufacturing precision
If purification process is intensified to achieve ultra-high purity, then MMA purity is improved, but polymerization risk increases
Solution Approach 1:
The purification process is segmented into two parallel distillation columns, allowing each column to operate at lower individual temperatures and residence times, reducing polymerization risk while achieving cumulative ultra-high purity through the combined separation of light and heavy impurities
Solution Approach 2:
The system maintains continuous operation with MMA being constantly recovered and circulated through the lateral extraction system, preventing accumulation and extended exposure to conditions that could trigger polymerization
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 achieves MMA purity higher than 99.90wt% with MMA losses less than 0.5%, significantly improving yield and controlling polymerization, thereby producing high-quality MMA suitable for optical-grade PMMA production.
Implementation Method 1
two distillation columns (210, 250) in series, fed with mixture to be distilled
Implementation Method 2
separate crude MMA from light and heavy impurities by distilling the mixture in the two distillation columns
Implementation Method 3
a condenser system for liquefying gas phase
Implementation Method 4
a cooling device (222) for cooling the obtained mixture, at a temperature between 20°C and 34°C
Implementation Method 5
a settler (223) for recovering the liquid phase and for obtaining a phase separation between an aqueous phase containing water and methanol, and an organic phase containing methyl methacrylate (MMA)
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a purification unit (200) which is able to separate crude MMA from light and heavy impurities in order to obtain high quality of MMA, suitable to produce optimal grade polymethylmethacrylate (PMMA). The unit (200) comprises two distillation columns (210, 250) in series, fed with mixture to be distilled in their median part, in order to separate each column in two upper (213, 253) and lower (212, 252) parts, the first distillation column (210) being fed with crude prewashed MMA, and the second distillation column (250) being fed with distilled liquid stream containing MMA, separated from light impurities, issued from bottom of first distillation column (210). The upper part (213) of first distillation column (210) is connected to a lateral extraction system (220), able to minimize MMA content in light impurities flowing upward said first column (210).