Two-Stage Conical Refining for Cost-Efficient Pulp Fibrillation
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Solution Overview
Problem
Existing methods for producing microfibrillated cellulose (MFC) or nanocellulose are expensive due to high investment costs and excessive energy consumption, and they produce a higher degree of fibrillation than necessary for use as an additive in multi-layered paperboard.
Innovation Solution
A two-stage conical refining process using conical refiners with specific plate widths, groove widths, and rotational speeds, combined with alkali or enzyme pretreatment, to produce highly refined pulp efficiently and cost-effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If homogenizer or prior art methods are used to produce MFC or nanocellulose, then high fibrillation degree is achieved, but production costs and energy consumption become excessive
Solution Approach 1:
The patent changes the mechanical parameters of the refining process by using conical refiners with specific bar widths (0.5-1.5 mm) and groove widths (0.5-1.5 mm) instead of homogenizers. This parameter change achieves the required fibrillation degree with significantly lower energy consumption, as the conical refiner geometry is optimized for controlled fiber separation without excessive mechanical agitation.
Solution Approach 2:
The patent replaces the high-shear mechanical system of a homogenizer with a conical refiner system that uses a rotating cone between stationary plates. This substitution maintains the ability to produce fibrillated cellulose while reducing the intensity of mechanical action, thereby lowering energy consumption while preserving the required fibrillation for paperboard applications.
2Manufacturing precision
If homogenizer or prior art methods are used to produce MFC or nanocellulose, then high fibrillation degree is achieved, but investment costs become high
Solution Approach 1:
The patent employs conical refiners with relatively simple geometric structures (cone and plates) that are less complex and less expensive than homogenizers. The refining plates with specific bar and groove dimensions provide a cost-effective solution for achieving fibrillation without requiring complex high-shear mixing mechanisms, thereby reducing investment costs while maintaining product quality.
Solution Approach 2:
The conical refiner system serves multiple functions: it refines the pulp structure, controls fibrillation degree, and can be integrated into existing paperboard production lines. This multi-functionality reduces the need for separate specialized equipment, thereby lowering overall investment costs while achieving the required manufacturing precision for paperboard applications.
3Manufacturing precision
If prior art methods are used, then MFC or nanocellulose is produced, but the fibrillation level is higher than needed for paperboard additive application
Solution Approach 1:
The patent applies partial action by using conical refiners with specific bar widths (0.5-1.5 mm) and groove widths (0.5-1.5 mm) that provide just enough mechanical action to achieve the required fibrillation degree for paperboard applications, without excessive over-refining. This controlled partial action reduces energy consumption and process time while maintaining the minimum necessary fibrillation level for effective paperboard additive performance.
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
Reduces production costs and energy consumption while achieving the required fibrillation level for paperboard applications, enhancing the bonding properties of paperboard layers.
Implementation Method 1
subjecting the pulp to a first conical refining step in a conical refiner comprising refining plates having a bar width of 0.5-1.5 mm... and a groove width of 0.5-1.5 mm; and subjecting the pulp from the first conical refining step to a second conical refining step in at least one conical refiner comprising refining plates having a bar width of 0.4-1.0 mm... and a groove width of 0.4-1.0 mm
Implementation Method 2
the pulp is pretreated with alkali before the first conical refining step; wherein the pH of the pulp in the alkali pretreatment is in the range of 8-11
Implementation Method 3
the pulp is pretreated with enzymes before the first conical refining step
Data Source
AI summary
There is provided a method of producing a highly refined pulp, comprising the steps of: providing a pulp; subjecting the pulp to a first conical refining step in at least one conical refiner comprising refining plates having a bar width of 0.5-1.5 mm, such as about 1.0 mm, and a groove width of 1.0-2.0 mm, such as 1.4-2.0 mm, such as about 1.6 mm; and subjecting the pulp from the first conical refining step to a second conical refining step in at least one conical refiner comprising refining plates having a bar width of 0.5-1.5 mm, such as about 1.0 mm, and a groove width of 0.8-1.6 mm, such as 1.0-1.5 mm, to obtain the highly refined pulp.