Twin-Screw Defibrillation for High-Density Cellulose
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Solution Overview
Problem
Existing methods for defibrillating cellulose fibers require high energy input, making them economically and environmentally inefficient for producing high-density materials like 3-dimensional objects, wall and floor boards, and tiles.
Innovation Solution
A method involving single or multiple passes of a cellulose fiber slurry with a consistency range of 35% to 55% through twin-screw fiber processing machines, optionally enhanced with additives, to achieve hyperdefibrillation with a Schopper-Riegler value of at least 80° SR and a density of at least 850 kg/m³, reducing energy and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional beating and refining processes are used to open and fibrillate cellulose fibers, then fiber opening and fibrillation are achieved, but large amounts of energy are expended with relatively minor amounts of fiber opening and fibrillation
Solution Approach 1:
The patent replaces traditional mechanical beating and refining systems with a high-pressure homogenizer that uses hydraulic pressure and shear forces to achieve fiber opening and fibrillation. This substitution of mechanical systems allows for more efficient energy utilization while achieving the desired fiber separation and fibrillation effects.
Solution Approach 2:
The patent changes the operating parameters by using high pressure (at least 3000 psi pressure drop) and controlled flow velocity through a homogenizer orifice, rather than traditional low-pressure mechanical beating. This parameter change enables efficient fiber opening and fibrillation with reduced energy consumption compared to conventional methods.
2Manufacturing precision
If high pressure homogenization is used to produce micro-cellulose with particle size of less than one micron, then fine particle size is achieved, but the process requires substantial chemical change or degradation
Solution Approach 1:
The patent uses a mechanical high-pressure homogenization system instead of chemical treatment methods to achieve fine particle size reduction. The mechanical shear forces and pressure differential through the homogenizer orifice enable particle size reduction to less than one micron without the need for chemical degradation or substantial chemical change.
3Manufacturing precision
If ball mills are used to prepare cellulose of several tens of microns in dimension, then fiber division is achieved, but chemical bonds of the cellulose are broken during the dividing process
Solution Approach 1:
The patent replaces ball mill mechanical impact systems with a high-pressure homogenization system that uses controlled hydraulic pressure and shear forces. This substitution achieves fiber division to several tens of microns in dimension while minimizing chemical bond breaking that occurs in ball mill processes.
Solution Approach 2:
The patent introduces a liquid medium (water or aqueous solution) as an intermediary between the cellulose fibers and the homogenization process. This liquid intermediary allows for controlled fiber separation and size reduction without direct mechanical impact that would break chemical bonds, achieving fine dimension control while preserving cellulose integrity.
4Manufacturing precision
If acid hydrolysis is used to produce finely divided celluloses in traditional mechanical pulp processes, then fine particle size is achieved, but the cellulose pulps are chemically altered or degraded
Solution Approach 1:
The patent substitutes chemical acid hydrolysis with a mechanical high-pressure homogenization system to achieve fine particle size. The homogenizer uses pressure differential and shear forces to divide cellulose into fine particles without chemical alteration or degradation of the cellulose structure.
Solution Approach 2:
The patent uses a liquid medium as an intermediary to enable particle size reduction without chemical treatment. The liquid allows for controlled homogenization and particle separation while maintaining the chemical integrity of the cellulose, avoiding the harmful effects of acid hydrolysis.
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 significantly reduces energy consumption and processing time while achieving higher output and consistency, enabling the production of high-density cellulose microfiber compositions suitable for various applications, including 3-dimensional objects and building materials.
Implementation Method 1
The defibrillation is achieved through single and multiple passes of a raw or pre-processed cellulose fibre slurry, with a preferred solid material consistency range of 35% to 55%, through twin-screw fibre processing machines
Implementation Method 2
During this processing operation, fibre slurries are optionally further enhanced with additional fibre and mineral additives to optimise performance of the material for specific end purposes
Implementation Method 3
GB2066145 describes a process for preparing micro-fibrillated cellulose, comprising passing a liquid suspension of fibrous cellulose through an orifice in which the suspension is subjected to a pressure drop of at least 3000 psi and a high velocity shearing
Implementation Method 4
The suspension is subjected to a pressure drop of at least 3000 psi and a high velocity shearing, followed by a high velocity decelerating impact
Implementation Method 5
Processes for opening, beating or defibrillating pulp to obtain fibrillation, increased surface area, increased accessibility and fine particle size have long been known
Implementation Method 6
drying the body by removing water therefrom to harden and form a work piece, without admixture of bonding agents to the microfiber pulp and without use of external pressure
Data Source
Figure 1~2
Figure 3
AI summary
The current invention relates to a method and apparatus for defϊbrillating cellulose fibres, achieved through single or multiple passes of raw or pre-processed cellulose fibre slurry, with a preferred solid material consistency range of 35% to 55% through twin-screw fibre processing machines. During this processing operation fibre slurries are optionally further enhanced with additional fibre and mineral additives to optimise performance of the material for specific end purposes. The hyper defibrillated fibre slurry produced can be defined as one reaching a Schopper-Riegler (SR) level between 75 SR and 85 SR and/or producing a pressed, dried board with a density of preferably at least 850 kg/m3.