Longitudinal Splitting of Cellulosic Fibers via Venturi Pressure Gradient
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Solution Overview
Problem
The pulp and paper industry faces challenges due to closed tracheids in wood fibers, which prevent efficient washing, bleaching, and drying, as they retain spent liquor and chemicals inside the fiber lumen, leading to energy-intensive processing and environmental pollution.
Innovation Solution
A method and apparatus for longitudinally splitting hollow cellulosic fibers using a gaseous flow through a venturi tube, creating a pressure difference that opens the fiber lumen, allowing for efficient washing, bleaching, and drying by enabling direct access to the interior of the fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional washing methods are used on fibers with closed tracheids, then the washing process is simple, but spent liquor and chemicals remain trapped inside the fiber lumen, reducing washing efficiency and increasing environmental pollution
Solution Approach 1:
The fiber wall is segmented by creating longitudinal splits that divide the closed tracheid structure into open sections. This segmentation allows washing liquor to access the interior lumen of fibers, enabling recovery of spent chemicals that would otherwise remain trapped. The splits create multiple access points along the fiber length, transforming the closed single-chamber structure into an open segmented configuration.
2Use of energy by moving object
If conventional drying methods are used on fibers with closed tracheids, then the drying process is straightforward, but energy consumption is high due to retained moisture inside the fiber lumen
Solution Approach 1:
The closed fiber structure is segmented through longitudinal splitting, creating open pathways that allow moisture to escape more easily during drying. This segmentation transforms the drying process from removing moisture through the fiber wall to evaporating moisture from exposed interior surfaces, significantly reducing the energy required to achieve the same drying level.
Solution Approach 2:
The retained moisture trapped inside the closed fiber lumen is extracted and removed through the longitudinal splits. By creating openings along the fiber length, the moisture that would otherwise require high energy input to evaporate through the fiber wall is now accessible to drying media, allowing more efficient moisture extraction with lower energy consumption.
3Reliability
If conventional bleaching methods are used on fibers with closed tracheids, then the bleaching process is simple, but chemicals cannot efficiently reach the interior of fibers, reducing bleaching effectiveness
Solution Approach 1:
The fiber structure is segmented by longitudinal splitting, creating multiple access points that allow bleaching chemicals to penetrate into the fiber lumen. This segmentation transforms the bleaching process from surface-only treatment to interior-accessible treatment, ensuring thorough and effective bleaching of the entire fiber structure including previously inaccessible interior regions.
4Manufacturing precision
If traditional pulp processing methods are used, then the processing steps are straightforward, but paper quality is limited due to inability to thoroughly remove impurities and efficiently evaporate moisture
Solution Approach 1:
The fiber structure is segmented through longitudinal splitting, creating open configurations that enable thorough removal of impurities and efficient moisture evaporation. This segmentation allows washing, bleaching, and drying processes to access the entire fiber structure, resulting in higher quality paper products with fewer residual contaminants and better moisture control.
Solution Approach 2:
The fiber structure is preliminarily modified by creating longitudinal splits before subsequent processing steps. This preliminary action opens the fiber lumen and creates access pathways, enabling more effective washing, bleaching, and drying operations to follow, ultimately improving paper quality by ensuring thorough treatment of all fiber regions.
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 enhances the recovery of spent chemicals, reduces energy consumption in drying, and improves paper quality by allowing thorough removal of impurities and efficient moisture evaporation, thus addressing the limitations of traditional pulp processing methods.
Implementation Method 1
the pressure drop in the venturi tube throat brings a pressure difference between the inside and the outside of the fibers and causes the fibers to split in their longitudinal direction
Implementation Method 2
conducting the gaseous flow carrying the fibers through a venturi tube
Data Source
AI summary
A method of splitting hollow cellulosic fibers employs the steps of wetting the fibers, feeding the wet fibers to a gaseous flow, and conducting the gaseous flow carrying the fibers through a venturi tube, the pressure drop in the venturi tube throat bringing a pressure difference between liquid inside the fibers and gas outside of the fibers and causing the fibers to split in their longitudinal direction, to open the lumen inside the fibers.