Ethylene Carbonate Purification via Dynamic Crystallization
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Solution Overview
Problem
Current methods for purifying ethylene carbonate, such as rectification and molecular sieve adsorption, are energy-intensive, costly, and result in low purity products due to high energy consumption and complex operation conditions, while also leading to the loss of ethylene carbonate during the purification process.
Innovation Solution
A method utilizing dynamic crystallization in a rake dryer with controlled temperature differences and stirring speeds to produce high-purity ethylene carbonate crystals, where the temperature in the cavity is gradually reduced by cooling water, and a seed crystal is added to initiate crystallization, allowing for efficient separation and recycling of mother liquor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rectification is used to purify ethylene carbonate, then separation of EC from ethylene glycol is achieved, but energy consumption is high and operation period is long
Solution Approach 1:
The patent employs crystallization, a phase transition process, to purify ethylene carbonate. By controlling temperature to induce crystallization of EC from the liquid mixture, the method achieves separation without the high energy consumption of rectification. The EC crystallizes out while impurities remain in the mother liquor, enabling energy-efficient purification.
Solution Approach 2:
The patent utilizes temperature parameter changes to control the crystallization process. By gradually lowering the temperature from ambient to -10°C or lower, the solubility of EC changes, causing it to crystallize. This temperature-controlled approach replaces energy-intensive rectification with a simpler thermal process.
2Manufacturing precision
If molecular sieve adsorption is used to remove impurities, then dehydration and ethylene glycol removal are achieved, but ethylene carbonate is adsorbed along with impurities resulting in loss of EC and reduction of yield
Solution Approach 1:
Instead of using molecular sieve adsorption that causes EC loss, the patent employs crystallization where EC transitions from dissolved state to solid crystal form. This phase transition enables selective separation based on solubility differences, allowing EC to be recovered as pure crystals while impurities remain in solution, thus avoiding the adsorption losses inherent in molecular sieve methods.
Solution Approach 2:
The patent extracts EC from the liquid mixture by inducing crystallization. The EC is taken out of the solution phase and precipitated as solid crystals, separating it from the mother liquor containing impurities. This extraction method avoids the non-selective adsorption of molecular sieves that co-adsorb EC with impurities.
3Manufacturing precision
If molecular sieve is used in large amount for adsorption, then impurity removal is achieved, but process complexity increases and cost is high
Solution Approach 1:
The patent replaces complex molecular sieve adsorption processes with a simple crystallization process. By controlling temperature to induce EC crystallization, the method achieves purification through a single phase transition step rather than multiple adsorption stages, significantly simplifying the process equipment and operation while maintaining high purity.
Solution Approach 2:
The patent replaces the mechanical adsorption system (molecular sieves requiring complex loading, regeneration, and operation) with a thermal crystallization system. The crystallization process uses temperature control and natural phase transition, eliminating the need for complex adsorption equipment and reducing operational complexity.
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 achieves high-purity ethylene carbonate with improved yield and reduced energy consumption, simplifying the process and increasing production efficiency, making it suitable for industrial application.
Implementation Method 1
the jacket is provided with cooling water therein, a water temperature of the cooling water in the jacket is controlled to be 1-2.5° C. lower than the temperature in the cavity
Implementation Method 2
a seed crystal is added to initiate crystallization
Implementation Method 3
crystal formation in the process of crystallization is initiated by adding a seed crystal
Data Source
AI summary
The present invention relates to the technical field of chemical industry, and in particular to a method for purifying ethylene carbonate through dynamic crystallization, which includes the following steps: adding an ethylene carbonate-containing raw material into a cavity of a crystallization device under a condition of stirring for dynamic crystallization, wherein the crystallization device further includes a jacket attached and circumferentially disposed along the outer wall of the cavity, the jacket is provided with cooling water therein, a temperature of the cooling water is 1-2.5° C. lower than the temperature in the cavity until a granular ethylene carbonate crystal is generated. The present invention using a rake dryer as the crystallization device to realize dynamic crystallization at a certain rotating speed. The technical solution is simple to operate and short in processing cycle, which facilitates improvement in production efficiency and product quality and is suitable for industrial application.