Conical Pulp Refining for Energy-Efficient Fiber 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 method utilizing conical refiners with specific plate configurations and refining steps to produce highly refined pulp, optimizing energy efficiency and reducing investment costs, involving two conical refining steps with varying bar and groove widths, and controlling energy and load application based on pulp conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If homogenizer or prior art methods are used to produce MFC or nanocellulose, then high degree of fibrillation is achieved, but investment costs and energy consumption become excessively high

Engineering Contradiction:
Improvedegree of fibrillationVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The invention changes the refining parameters by using conical refiners with specific bar widths (0.5-1.5 mm) and groove widths (0.5-1.5 mm) instead of homogenizers. The specific edge load is controlled at 0.1-0.5 J/m, which is lower than conventional methods, achieving the desired fibrillation degree with reduced energy input. The two-stage refining process with different plate configurations optimizes energy efficiency while maintaining product quality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the high-energy homogenizer mechanical system with a conical refiner system that uses controlled mechanical action between refining plates. This substitution reduces energy consumption by using a more efficient mechanical refining mechanism that achieves fibrillation through controlled shear forces rather than high-energy impact.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If homogenizer or prior art methods are used to produce MFC or nanocellulose, then high degree of fibrillation is achieved, but investment costs become excessively high

Engineering Contradiction:
Improvedegree of fibrillationVSAvoidinvestment costs
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention uses conical refiners that can process different types of pulp (virgin fibers, recycled fibers, blends) and produce refined pulp suitable for various paperboard applications. This multi-functionality reduces the need for specialized expensive equipment like homogenizers, thereby lowering investment costs while maintaining manufacturing capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

By changing the refining parameters (bar width, groove width, specific edge load) in the conical refiner system, the invention achieves the desired fibrillation degree using conventional refiner technology rather than expensive specialized equipment, thus reducing investment costs while maintaining product quality.

Inventive Principle:
Principle #35Parameter changes

3Strength

If high degree of fibrillation is produced, then bonding properties are enhanced, but energy consumption and production costs increase excessively

Engineering Contradiction:
Improvebonding propertiesVSAvoidproduction costs
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The invention optimizes the specific edge load parameter to 0.1-0.5 J/m in the conical refiner, which is sufficient to achieve the bonding properties needed for paperboard applications without excessive energy input. The two-stage refining process with progressively different plate configurations ensures adequate fibrillation for bonding while minimizing energy consumption and production costs.

Inventive Principle:
Principle #35Parameter changes

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 energy-efficient production of highly refined pulp suitable for paperboard applications, reducing production costs and enhancing the bonding properties of paperboard layers without excessive fibrillation.

Implementation Method 1

The refiner comprises a stationary refiner plate and a rotating refiner plate. The bar width is 0.5-1.5 mm and the groove width is 0.5-1.5 mm

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

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, and a groove width of 0.5-1.5 mm

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP4148182B1Production method
Publication Date: 2025.11.19 BILLERUD AB
  • EP4148182B1 patent drawingFigure 1
  • EP4148182B1 patent drawingFigure 2

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.