Efficient raw material resource utilization for paper through use of microfibrillated cellulose (MFC)

2014-12-09
Per Svending
Jon Phipps

Microfibrillated cellulose (MFC)

  • Microfibrillated cellulose (MFC)First made in the 80’s
    • Very high energy demand (25-30 MWh/ton)
    • Using expensive and sophisticated grinding equipment
    • Expensive and very high capex/capacity ratio
  • Conventional state of the art
    • Pulp pre-treatment for to soften up the fibers
    • Significantly reduced energy demand
    • Still using expensive and sophisticated grinding equipment
    • Still very high capex/capacity ratio
    • Low solids product in gel form, often with high surface charge
    • Scale limitations are preventing large volume applications

In practice “conventional” MFC is still restricted to high value applications.

The FiberLean™ microfibrillated cellulose process

  • Co-grinding of pulp to MFC in the presence of minerals.
    • The mineral acts as a very fine grinding media
  • Robust and reliable equipment of relevant industrial scale.
  • On-site manufacturing, using a minor side stream of mill pulp.
  • No pre-treatment of fiber required.
  • The FiberLean product is a MFC/mineral composite.
  • FiberLean is used to increase filler loading in paper without sacrificing paper quality or paper machine efficiency.

An industrial scale, MFC process for on-site installation

An industrial scale, MFC process for on-site installation

An industrial scale, MFC process for on-site installation 2 000 dry ton per year capacity.

FiberLean™ is made out of filler and fiber

 

Composite made out of Filler and Fiber

Picture of paper surface with FiberLean™ MFC

 

Close up picture of paper with FiberLean MFC

Note the similarity between the original FiberLean™ composite and the product as retained in the paper.

similarity between the original composite and the productThe association between the filler and the MFC remains through the paper making process.

Filler increase with GCC without strength additives

impact on paper properties when going from 20% to 30% filler

Impact on paper properties when going from 20% to 30%Lab study
Mesmer recirculating hand sheets (12 sheets)
70% Eucalyptus, 30% NBSK, 550 CSF
Intracarb 60 filler

The impact of increasing filler loading

Impact on: +10% filler Comments:
Cost savings: +++ Filler is cheaper than pulp
Opacity: ++
Brightness: ++
Smoothness: +
Drainage: ++ Less fiber to drain
Strengths: – – – Wet-strength – runnability, dry strength – quality
Porosity: Higher porosity depending on filler type
Bulk: Depending on filler type

Loss of strength is typically the show stopper.

Impact of MFC on paper strength

Impact of MFC on paper strengthLab study
Mesmer recirculating hand sheets (12 sheets)
70% Eucalyptus, 30% NBSK, 550 CSF
Intracarb 60 filler

It is possible to increase filler by 10% or more and suffer no strength loss.

Impact of MFC on paper tensile

Impact of MFC on paper tensileLab study
Mesmer recirculating hand sheets (12 sheets)
70% Eucalyptus, 30% NBSK, 550 CSF
Intracarb 60 filler

Impact of MFC on optical properties

Impact of MFC on optical propertiesLab study
Mesmer recirculating hand sheets (12 sheets)
70% Eucalyptus, 30% NBSK, 550 CSF
Intracarb 60 filler

Impact of MFC on other properties

Impact of MFC on other propertiesLab study
Mesmer recirculating hand sheets (12 sheets)
70% Eucalyptus, 30% NBSK, 550 CSF
Intracarb 60 filler

  • The porosity impact can be important for hold-out of ink or coating colour.
  • Density can be regained by trading the positive impact on smoothness and bond strength with less intense calendering and/or use of coarser fiber, such as CTMP.
  • While initial drainage slows down there is a positive impact on couch and press solids.

The impact of increasing filler loading with the help of MFC

Impact on: +10% filler +10% filler with MFC Comments:
Cost savings: +++ + Cost of MFC…
Opacity: ++ +++ Even higher with MFC
Brightness: ++ + A little less improved
Smoothness: + ++ Better with MFC
Drainage: ++ + MFC holds back some of the benefit
Strengths: – – – +/- Wet-strength – runnability, dry strength – quality
Porosity: +++ Much lower porosity with MFC
Bulk: – – MFC doesn’t help. Needs paper making trade off’s

Selecting correct filler loading – simplified example

Selecting correct filler loading - simplified example

Selecting correct filler loading and sheet weight with FiberLean

Pilot paper machine data

Selecting correct filler loading and sheet weight with FiberLean

Selecting correct filler loading and sheet weight with FiberLean

Pilot paper machine data

Selecting correct filler loading and sheet weight

Selecting correct filler loading and sheet weight with FiberLean

Pilot paper machine data

Selecting correct filler loading and sheet weight

Selecting correct filler loading and sheet weight with FiberLean

Pilot paper machine data

Selecting correct filler loading and sheet weight with FiberLean

Conclusions

  • Converting a small part of the pulp to MFC opens up new opportunities.
  • The traditional idea of replacing pulp with filler and MFC is exciting and can offer nice cost savings.
  • The idea of using MFC to tailor a paper grade to meet required opacity and strength targets with minimum raw material use is even more exciting!
  • There could be major fiber savings!
    • The example given suggests:
      • 24% fiber savings from 2% MFC
      • 34% fiber savings from 4% MFC