NVP Crystallization Water Control and Segmentation
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Solution Overview
Problem
The existing methods for producing high-purity N-vinyl-2-pyrrolidone (NVP) face inefficiencies due to low purity input in the first crystallization process, leading to high loads on the crystal purification process and reduced production efficiency, with impurities causing plugging in crystallizers and disrupting stable operation.
Innovation Solution
A method involving at least two crystallization processes, where the mother liquor from the first crystallization process is supplied to the second crystallization process, and crystals undergo a sweating phenomenon in a crystal purification process, with controlled water content in the feed solution to prevent plugging and enhance purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the mother liquor from the first crystallization process is recycled to the first crystallization process, then the concentration of impurities can be controlled, but the purity of NVP obtained is low and the load on the crystal purification process is high
Solution Approach 1:
The crystallization process is divided into two separate crystallization processes (first and second crystallization processes) instead of recycling mother liquor to the same process. This segmentation allows each process to handle different purity levels and prevents impurity accumulation that would occur with recycling, thereby maintaining high NVP purity while still controlling impurity concentrations.
Solution Approach 2:
The mother liquor from the first crystallization process serves as an intermediary material that is transferred to the second crystallization process. This intermediary role allows the mother liquor to be utilized effectively without contaminating the first crystallization process, enabling high-purity NVP production while still benefiting from the impurity control mechanism.
2Manufacturing precision
If much time is spent in the purification process to obtain high-purity NVP, then the purity increases, but the production efficiency decreases
Solution Approach 1:
The first crystallization process performs preliminary purification by removing a significant portion of impurities before the second crystallization process. This preliminary action reduces the burden on the crystal purification process and shortens the overall time required to achieve high-purity NVP, thereby improving production efficiency while maintaining high purity standards.
Solution Approach 2:
The mother liquor from the first crystallization process is continuously supplied to the second crystallization process, creating a continuous flow of useful action. This continuity eliminates idle time and ensures that the purification process operates efficiently without interruptions, maintaining high production efficiency while achieving the required purity levels.
3Device complexity
If the concentration of impurities is not controlled, then the production process is simple, but crystals deposit on the heat transfer surface causing plugging and suspending operation
Solution Approach 1:
The system implements feedback control by measuring the concentration of impurities and water content in the feed NVP solution and adjusting the process parameters accordingly. This feedback mechanism ensures that impurity concentrations are kept within ranges that prevent crystal deposition on heat transfer surfaces, maintaining reliable and continuous operation without requiring complex process design.
Solution Approach 2:
The invention controls specific parameters (concentration of impurities and water content) to prevent crystal deposition. By monitoring and adjusting these parameters, the system maintains stable operation and prevents plugging of the heat transfer surface, achieving reliable production without excessive process complexity.
4Ease of operation
If water content in feed NVP solution is not controlled, then the operation is simple, but crystals deposit on the heat transfer surface causing plugging
Solution Approach 1:
The invention identifies and controls the water content parameter in the feed NVP solution to prevent crystal deposition. By maintaining water content within a specific range, the system prevents plugging of the heat transfer surface while keeping the operation relatively simple. This parameter control ensures stable production without requiring complex operational procedures.
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 stabilizes high-purity NVP production by reducing the load on the purification process, improving efficiency, and preventing crystallizer plugging, resulting in higher purity NVP with increased production rates.
Implementation Method 1
a production method of NVP characterized by comprising at least two crystallization processes, supplying the mother liquor from the first crystallization process to second crystallization process
Implementation Method 2
supplying, as needed, the crystals from the crystallization processes to a crystal purification process where a sweating phenomenon is applied
Data Source
AI summary
A method for producing N-vinyl-2-pyrrolidone by crystallization including: controlling a water content in a feed N-vinyl-2-pyrrolidone solution at an inlet of a crystallizer so as to be not lower than 0.7% by weight and not higher than 10% by weight based on the total weight of the N-vinyl-2-pyrrolidone solution; and supplying the feed N-vinyl-2-pyrrolidone solution to a crystallization process.