Cooled Surface Spinning Solution Distribution for Cold-Alkali Fiber Production
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production of regenerated cellulosic fibers through the cold-alkali process faces challenges in setting up process conditions, particularly in achieving the desired properties of tenacity, low brittleness, and appropriate crimp in staple fibers. Additionally, the need for massive cooling of the spinning dope demands innovative methods and apparatus for scale-up to large-scale industry.
Innovation Solution
A method and apparatus for preparing a cooled spinning solution by distributing it over a cooled surface using a distributing blade, allowing for efficient cooling and homogenization. This approach reduces energy expenditure and improves the quality of the spinning solution, enabling its use in the cold-alkali process for producing high-quality regenerated cellulosic fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If massive cooling of the spinning dope is implemented, then the spinning solution temperature is controlled to prevent heating above gelling temperature, but the energy consumption increases significantly
Solution Approach 1:
The cooling process is segmented into multiple stages: initial cooling during mixing, followed by controlled cooling during distribution over the cooled surface, and final cooling before extrusion. This segmentation allows temperature control at critical points without requiring continuous massive cooling throughout the entire process, thereby reducing overall energy consumption while maintaining temperature within the required range to prevent gelling.
Solution Approach 2:
The cooling action is performed preliminarily during the mixing and distribution stages before the extrusion step. By pre-cooling the spinning solution and distributing it over a cooled surface, the temperature is controlled in advance to prevent heating above the gelling temperature during subsequent processing, eliminating the need for intensive cooling interventions later in the process.
2Manufacturing precision
If the spinning solution is distributed over a cooled surface using a distributing blade, then cooling efficiency and homogenization are improved, but the device complexity increases
Solution Approach 1:
The distributing blade serves multiple functions simultaneously: it distributes the spinning solution uniformly over the cooled surface, facilitates controlled cooling through contact with the cooled surface, and ensures homogenization of the solution. This multi-functionality reduces the need for separate dedicated components for each function, thereby managing device complexity while achieving improved cooling efficiency and homogenization.
Solution Approach 2:
The cooled surface acts as an intermediary element between the spinning solution and the cooling system. Instead of directly immersing the solution in a cooling medium, the solution is distributed over the cooled surface, which transfers heat efficiently while maintaining solution homogeneity. This intermediary approach simplifies the overall cooling apparatus structure compared to direct cooling methods.
3Productivity
If the cold-alkali process is scaled up to large-scale industry, then production capacity increases, but the difficulty of setting up process conditions increases
Solution Approach 1:
The process conditions are optimized for large-scale production by adjusting key parameters: the cooling surface temperature is maintained within a specific range (e.g., 0-10°C) to prevent gelling, the distributing blade speed and gap dimensions are optimized for high throughput, and the spinning solution concentration and flow rate are adjusted to ensure proper distribution and cooling. These parameter changes enable scalable production while maintaining control over process conditions.
Solution Approach 2:
A feedback control system is implemented to monitor and adjust process conditions during scale-up. Temperature sensors monitor the spinning solution and cooled surface, pH sensors monitor the alkaline environment, and flow meters monitor the spinning solution rate. This feedback allows real-time adjustment of cooling intensity, mixing speed, and distribution parameters to maintain optimal process conditions at large scale, reducing the difficulty of setup and operation.
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 method achieves high-quality spinning solutions with reduced energy consumption, facilitating the scale-up of the cold-alkali process to large-industry standards while ensuring the desired properties of the produced fibers.
Implementation Method 1
the cooled surface has to be cooled below the gelling temperature of the spinning solution. During the mixing of the components, which is usually done in a high-shear mixer, a considerable amount of heat can be input into the spinning solution and the implementation of an adequate cooling for the mixing vessel has proven difficult and energy consuming.
Implementation Method 2
by distributing the spinning solution over a cooled surface with a distributing blade allows for the preparation of high-quality spinning solution at a rather low expenditure of energy. The distributing blade can be moved along the cooled surface, preferably in a repetitive manner, leaving a gap between the cooled surface and the distributing blade through which the spinning solution is pressed and distributed by the moving blade.
Implementation Method 3
The thus generated viscose-filaments are subsequently post processed. The post processing usually comprises several washing-and stretching steps and the filaments are cut to viscose-staple fibers.
Data Source
AI summary
A method for preparing a cooled spinning solution suitable for forming a regenerated cellulosic shaped body by extrusion into a coagulation bath. The method comprises at least one conditioning step during which the spinning solution is distributed over a cooled surface by at least one distributing blade.