Nanofibrillar Cellulose Production via Controlled Pre-beating
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Solution Overview
Problem
Current methods for producing nanofibrillar cellulose from cellulose pulp face challenges in achieving high purity and productivity, particularly when working with native cellulose, which is prone to clogging and requires minimal structural damage to preserve its native form, and existing methods often result in non-homogeneous products with enzymatic treatments or chemical modifications.
Innovation Solution
A method involving pre-beating cellulose pulp in a conical or disc refiner with controlled specific edge load to achieve a beating degree below 55 ml CSF, followed by high-pressure mechanical disintegration to produce nanofibrillar cellulose with specific rheological properties, ensuring minimal fiber cutting and maintaining the native form of cellulose, while maintaining clean conditions to prevent contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical disintegration is used to produce nanofibrillar cellulose, then production capacity is improved, but energy consumption increases and production capacity remains limited
Solution Approach 1:
The patent applies preliminary chemical modification to the cellulose pulp before mechanical disintegration. The pulp is treated with oxidizing agents or carboxymethylating agents to modify the cellulose structure, making it more susceptible to disintegration. This preliminary action reduces the energy required during the subsequent mechanical disintegration step while improving production capacity.
Solution Approach 2:
The patent changes the chemical parameters of the cellulose pulp by introducing functional groups through chemical modification. This alters the physical and chemical properties of the cellulose, making it easier to disintegrate mechanically with lower energy input, thus resolving the contradiction between productivity and energy consumption.
2Productivity
If chemical modification is applied to increase susceptibility to disintegration, then disintegration efficiency is improved, but the native form of cellulose is altered
Solution Approach 1:
The patent applies controlled chemical modification by introducing specific functional groups (carboxymethyl groups or oxidized groups) at controlled levels. This allows improvement of disintegration efficiency while maintaining the fundamental native structure of cellulose, achieving a balance between productivity and compositional stability.
Solution Approach 2:
The chemical modification is applied locally and selectively to specific sites on the cellulose chains rather than uniformly throughout the entire structure. This localized modification enhances disintegration susceptibility at critical points while preserving the overall native form and crystalline structure of the cellulose.
3Productivity
If enzymatic treatment is used, then disintegration is improved, but enzymes remain as contaminants requiring additional removal steps
Solution Approach 1:
The patent replaces enzymatic treatment with chemical modification using oxidizing agents or carboxymethylating agents. This substitution eliminates the contamination problem associated with enzyme residues while maintaining improved disintegration efficiency through chemical structural modification of the cellulose.
Solution Approach 2:
The patent uses chemical agents that can be easily removed or decomposed after treatment, unlike enzymes that persist as contaminants. The chemical modifiers are designed to be transient and removable, leaving no harmful residues in the final nanofibrillar cellulose product.
4Productivity
If extensive mechanical shearing is used, then nanofibrillar cellulose is produced, but the homogenizer becomes blocked and material is non-homogeneous
Solution Approach 1:
The patent applies chemical modification before mechanical shearing to pre-weakens the cellulose structure. This preliminary chemical treatment reduces the mechanical strength of the cellulose fibrils, allowing them to be more easily separated during homogenization without causing blockages and ensuring homogeneous distribution of nanofibrils in the final product.
Solution Approach 2:
The patent changes the mechanical properties of cellulose through chemical modification, altering its resistance to shearing forces. This parameter change enables smoother flow through the homogenizer and more uniform disintegration, preventing blockages and improving product homogeneity while maintaining productivity.
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 effectively produces high-purity nanofibrillar cellulose with desired rheological properties, reducing the risk of clogging and preserving the native form of cellulose, enabling its use in various applications, including medicine and biology, with improved productivity and minimal structural damage.
Implementation Method 1
prebeating the cellulose pulp by circulating the cellulose pulp in form of aqueous suspension of fibres through a refining gap formed by opposite arrays of refining bars which perform relative movement in the gap
Implementation Method 2
disintegrating the prebeaten pulp in a disintegration process to nanofibrillar cellulose
Data Source
Figure 1~2
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AI summary
In a method for producing nanofibrillar cellulose starting from cellulose pulp (P), where cellulose is in native form, the cellulose pulp is prebeaten by circulating it in form of aqueous suspension of fibres through a refining gap (G) formed by opposite arrays of refining bars which perform relative movement in the gap. The cellulose pulp is circulated until a beating degree of below 55 ml CSF, preferably 50 ml CSF or less, more preferably 20 ml CSF or less is attained. The prebeaten pulp is forwarded to a disintegration process (2), where the prebeaten pulp is disintegrated to nanofibrillar cellulose (NFC).