(Meth)acrylic Acid Crystallization via Supercooling
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Solution Overview
Problem
The challenge in producing highly pure (meth)acrylic acid is the lack of rigorous temperature control during crystallization, leading to unstable and inefficient purification, especially in large-scale industrial production where impurities and varying reaction conditions complicate the process.
Innovation Solution
A process involving preliminary cooling of the crude (meth)acrylic acid solution to stabilize the cooling medium temperature between the solidification point and 5°C above it, followed by supercooling the solution by setting the cooling medium temperature at least 1°C below the solidification point, and then crystallizing the acid using a falling liquid film type crystallization apparatus to achieve a clear supercooled state without premature precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the crude (meth)acrylic acid solution is cooled to the solidification point for crystallization, then (meth)acrylic acid crystals can be obtained, but impurities are also incorporated into the crystals resulting in low purity
Solution Approach 1:
The patent applies preliminary action by performing a first cooling step to stabilize the solution temperature close to the solidification point before the actual crystallization. This preliminary temperature stabilization ensures that when crystallization occurs, the temperature is already optimized, preventing impurity incorporation and ensuring high crystal purity while maintaining purification stability.
Solution Approach 2:
The patent segments the crystallization process into two distinct steps: (1) a preliminary cooling step to stabilize temperature close to the solidification point, and (2) a crystallization step where crystals are formed. This segmentation allows each step to be optimized independently, ensuring both high purity and stable purification.
2Productivity
If the cooling rate is increased to improve crystallization efficiency, then productivity increases, but crystal quality deteriorates and purity decreases
Solution Approach 1:
The patent applies preliminary action by performing a first cooling step to stabilize the solution temperature close to the solidification point before the actual crystallization. This preliminary temperature stabilization ensures that when crystallization occurs, the temperature is already optimized, preventing impurity incorporation and ensuring high crystal purity while maintaining purification stability.
Solution Approach 2:
The patent applies dynamics by using a cooling curve that changes the cooling rate over time. The cooling rate is adjusted based on the temperature difference between the solution and the solidification point, allowing for controlled crystallization that maintains both high productivity and crystal quality.
3Ease of operation
If the crude solution is preliminarily cooled to precipitate crystals before crystallization, then scale formation is suppressed and filterability improves, but the purity of the final crystal is not optimized
Solution Approach 1:
The patent applies preliminary action by performing a first cooling step to stabilize the solution temperature close to the solidification point before the actual crystallization. This preliminary temperature stabilization ensures that when crystallization occurs, the temperature is already optimized, preventing impurity incorporation and ensuring high crystal purity while maintaining purification stability.
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 method allows for the stable and efficient production of highly pure (meth)acrylic acid by maintaining the solution in a controlled supercooled state, reducing impurity content and improving crystal quality, making it suitable for large-scale industrial applications.
Implementation Method 1
a crude (meth)acrylic acid solution is cooled to the extent where a crystal does not precipitate before the solution is cooled down to not more than the solidification point for crystallization
Implementation Method 2
the crude solution is brought to a clear supercooled condition by cooling down to less than the solidification point
Implementation Method 3
crystallizing (meth)acrylic acid from the crude (meth)acrylic acid solution
Data Source
Figure 1
AI summary
The objective of the present invention is to provide a process for producing highly pure (meth)acrylic acid stably and efficiently with crystallization. The process for production of (meth)acrylic acid according to the present invention is characterized in comprising the steps of cooling a crude (meth)acrylic acid solution in a crystallization apparatus until the temperature of a cooling medium discharged from the crystallization apparatus is stabilized in the range of higher than the solidification point of the crude (meth)acrylic acid solution in the crystallization apparatus and not more than the solidification point plus 5°C; then bringing the crude (meth)acrylic acid solution in the crystallization apparatus to a supercooled condition by setting the temperature of a cooling medium supplied to the crystallization apparatus at the temperature of not more than the solidification point of the crude (meth)acrylic acid solution minus 1°C; and crystallizing (meth)acrylic acid from the crude (meth)acrylic acid solution.