Caprolactam Washing Column Phase Inversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing caprolactam extraction processes using packed columns suffer from inadequate washing performance, particularly in large-scale operations, due to the retention of sulfur-containing impurities and high caprolactam loss, primarily attributed to low feed ratios and inefficient hydrodynamic concepts.
Innovation Solution
A process utilizing a sieve tray type wash column with an aqueous phase as the continuous phase and caprolactam as the dispersed phase, achieving a low feed ratio of 0.05 or less, which significantly increases hold-up and allows for effective impurity removal, including sulfur-containing compounds, with minimal water usage and reduced caprolactam loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a packed column is used for washing caprolactam in organic solvent, then the equipment structure is simple, but the washing performance is insufficient and sulfur-containing impurities are retained in the product
Solution Approach 1:
The invention changes the hydrodynamic parameters by inverting the phase distribution (making aqueous phase continuous and organic phase dispersed) and optimizing the feed ratio to 0.03-0.08, which fundamentally alters the washing performance and enables effective removal of sulfur-containing impurities while maintaining equipment simplicity
Solution Approach 2:
The invention inverts the conventional hydrodynamic concept by making the aqueous phase the continuous phase and the organic phase the dispersed phase, which is the reverse of traditional extraction columns. This inversion dramatically improves washing performance for sulfur-containing impurity removal
2Manufacturing precision
If a high feed ratio of washing liquid is used, then the washing performance improves, but the loss of caprolactam via washing liquid increases substantially
Solution Approach 1:
The invention optimizes the feed ratio parameter to a specific range of 0.03-0.08, which is significantly lower than conventional ratios. Combined with the inverted phase distribution, this parameter change achieves effective washing performance while minimizing caprolactam loss to acceptable levels
Solution Approach 2:
The invention creates a dynamic hydrodynamic system where the organic phase forms dispersed droplets that are continuously renewed as they pass through the aqueous phase. This dynamic dispersion and renewal mechanism enhances mass transfer efficiency at low feed ratios, improving washing performance without proportionally increasing caprolactam loss
3Productivity
If the column size is scaled up to commercial scale, then the production capacity increases, but the washing performance deteriorates due to hydrodynamic limitations
Solution Approach 1:
The inverted phase distribution (aqueous continuous, organic dispersed) creates a hydrodynamic regime that scales more effectively to large diameters. The continuous aqueous phase can accommodate larger column sizes while maintaining effective contact with dispersed organic droplets, preserving washing performance at commercial scales
Solution Approach 2:
The organic phase is segmented into numerous small dispersed droplets throughout the continuous aqueous phase. This segmentation increases the total interfacial area for mass transfer and ensures that even in large diameter columns, all organic material is effectively exposed to the washing liquid, maintaining performance during scale-up
4Adaptability or versatility
If conventional extraction equipment is used, then the process is established, but maintenance requirements are high and operational reliability is reduced
Solution Approach 1:
By changing the phase distribution parameter and operating at optimized feed ratios, the invention reduces operational challenges such as channeling and maldistribution that plague conventional equipment. This leads to more stable, reliable operation with reduced maintenance needs while remaining adaptable to existing equipment types
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 enables efficient removal of impurities to low ppm levels while minimizing caprolactam loss and water consumption, maintaining high washing performance across various column sizes, and reducing maintenance requirements.
Implementation Method 1
extracting an impurity, in particular a sulphur-containing compound, from an organic phase comprising caprolactam, with an aqueous phase in a specific way... extracting the impurity by washing said organic phase as a discontinuous phase with an aqueous phase as a continuous phase
Data Source
AI summary
The invention relates to a process for extracting an impurity from an organic phase comprising caprolactam, comprising extracting the impurity by washing said organic phase as a discontinuous phase with an aqueous phase as a continuous phase, the ratio of the flow of the aqueous phase in m3/hr, to the flow of the organic phase in m3/hr, being 0.05 or less. Further the invention relates to a caprolactam production plant, wherein use can be made of a process of the invention.