Inline Dilution of Microfibrillated Cellulose Using Rotor-Stator Mixers

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Solution Overview

Problem

Existing methods for diluting microfibrillated cellulose (MFC) to lower solids content at the point-of-use are inefficient, often leading to agglomeration and loss of water retention capacity, and are difficult to scale up or reproduce consistently.

Innovation Solution

The use of rotor-stator mixers for continuous inline dilution of MFC, where solvent is injected upstream to reduce solids content from 5% to 0.1% w/w, with energy input and retention times optimized to maintain or enhance water retention capacity and viscosity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If MFC is transported as a high solids content paste to minimize transportation costs, then transportation efficiency is improved, but the MFC requires dilution at point-of-use which is difficult to scale up and reproduce consistently

Engineering Contradiction:

Improvetransportation costVSAvoiddilution process efficiency

Core Design Contradiction:

Loss of energyVSProductivity

Solution Approach 1:

The patent replaces traditional mechanical mixing systems (high-speed mixers, blenders) with an inline dilution system that uses controlled solvent injection and low-shear mixing. This substitution enables scalable and reproducible dilution while maintaining MFC properties, resolving the contradiction between transportation efficiency and dilution scalability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Speed

If conventional high-speed mixing is used to disperse MFC during dilution, then dispersion speed is improved, but MFC aggregates and water retention capacity is lost

Engineering Contradiction:

Improvemixing speedVSAvoidwater retention capacity

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent changes the mixing parameters from high-speed to low-shear mixing conditions during inline dilution. This parameter change prevents MFC aggregation and maintains water retention capacity while still achieving effective dispersion, resolving the contradiction between mixing speed and MFC property preservation.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If MFC is diluted to low solids content at point-of-use, then application performance is improved, but additional equipment (mixing and holding tanks) and process complexity are required

Engineering Contradiction:

Improveapplication readinessVSAvoidequipment requirement

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the dilution process with the existing application process by implementing inline dilution directly in the application line. This eliminates the need for separate mixing and holding tanks, reducing equipment complexity while maintaining ease of operation and application readiness.

Inventive Principle:

Principle #5Merging (Combining)

4Productivity

If rapid dilution is performed to improve productivity, then dilution speed is improved, but foaming issues occur and MFC properties deteriorate

Engineering Contradiction:

Improvedilution speedVSAvoidfoaming

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent implements continuous inline dilution where solvent is injected and mixing occurs continuously along the process line rather than in batch operations. This continuous action achieves rapid dilution without foaming issues and maintains MFC properties, resolving the contradiction between productivity and harmful effect generation.

Inventive Principle:

Principle #20Continuity of useful action

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 process achieves reproducible and efficient dilution with improved water retention and viscosity, avoiding agglomeration and foaming issues, and allows for precise control over the dilution process without the need for mixing and holding tanks.

Implementation Method 1

The use of rotor-stator mixers for continuous inline dilution of MFC

Methodology Applied

Scientific EffectTurbulence: Turbulence

Implementation Method 2

rotor-stator mixers for continuous inline dilution of MFC, where solvent is injected upstream to reduce solids content

Methodology Applied

Scientific EffectShear stress: Shear Stress

Data Source

PatentUS11851818B2Inline dilution of microfibrillated cellulose

Publication Date: 2023.12.26 BORREGAARD

AI summary

The present invention relates a process and a system for the point-of-use dilution of microfibrillated cellulose (MFC) from a higher solids content to a lower solids content, for example from a solids content in the range of 5% weight by weight (“w/w”)-50% w/w, preferably 5% w/w-30% w/w, further preferably 5% w/w-15% w/w, down to a solids content of below 7% w/w, preferably below 5% w/w, preferably to a solids content of 0.01% w/w-5% w/w, further preferably to a solids content of 0.1% w/w-3% w/w. The process at least comprises the following steps: (i) providing microfibrillated cellulose in a solvent, wherein the solids content is in the range of 5% weight by weight (“w/w”)-50% w/w, preferably 5% w/w-30% w/w, further preferably 5 w/w-15% w/w; (ii) subjecting said microfibrillated cellulose from step (i) to a dilution step in a rotor-stator mixer; (iii) simultaneously to step (ii): injecting solvent into the rotor-stator mixer, or into a volume segment upstream of the rotor-stator mixer, in order to lower the solids content of the microfibrillated cellulose in the rotor-stator mixer.