Table Of ContentThesis for the degree of Licentiate of Technology, Sundsvall 2008
BONDING ABILITY DISTRIBUTION OF FIBERS IN MECHANICAL
PULP FURNISHES
Sofia Reyier
Supervisors:
Professor Hans Höglund
Professor Per Engstrand
M.Sc. Olof Ferritsius
FSCN ! Fibre Science and Communication Network
Department of Natural Science
Mid Sweden University, SE!851 70 Sundsvall, Sweden
ISSN 1652!8948
Mid Sweden University Licentiate Thesis 31
ISBN 978!91!85317!90!5
Akademisk avhandling som med tillstånd av Mittuniversitetet i Sundsvall
framläggs till offentlig granskning för avläggande av teknologie licentiatexamen i
kemiteknik med inriktning mot mekanisk fiberteknologi, onsdagen den 18 juni,
2008, klockan 10.00 i sal ”Granen” på Stora Enso Kvarnsvedens Pappersbruk,
Borlänge. Seminariet kommer att hållas på svenska.
Ett förseminarium hålls fredagen den 9 maj klockan 10.30, sal N109 på
Mittuniversitetet i Sundsvall.
BONDING ABILITY DISTRIBUTION OF FIBERS IN MECHANICAL
PULP FURNISHES
Sofia Reyier
© Sofia Reyier, 2008
The figure on the cover page shows the BIN!distributions (Bonding Indicator) for
fibers of three different mechanical pulps, of fiber length 0.7!2.3 mm, predicted
from optical measurement raw data on whole pulps.
FSCN ! Fibre Science and Communication Network
Department of Natural Sciences
Mid Sweden University, SE!851 70 Sundsvall, Sweden
Telephone: +46 (0)771!975 000
Printed by Kopieringen Mittuniversitetet, Sundsvall, Sweden, 2008
i
BONDING ABILITY DISTRIBUTION OF FIBERS IN MECHANICAL
PULP FURNISHES
Sofia Reyier
FSCN ! Fibre Science and Communication Network, Department of Natural
Sciences, Mid Sweden University, SE!851 70 Sundsvall, Sweden
ISSN 1652!8948, Mid Sweden University Licentiate Thesis 31; ISBN 978!91!85317!
90!5
ABSTRACT
This thesis presents a method of measuring the distribution of fiber bonding ability
in mechanical pulp furnishes. The method is intended for industrial use, where
today only average values are used to describe fiber bonding ability, despite the
differences in morphology of the fibers entering the mill. Fiber bonding ability in
this paper refers to the mechanical fiber’s flexibility and ability to form large
contact areas to other fibers, characteristics required for good paper surfaces and
strength.
Five mechanical pulps (Pulps A!E), all produced in different processes from
Norway spruce (Picea Abies) were fractionated in hydrocyclones with respect to the
fiber bonding ability. Five streams were formed from the hydrocyclone
fractionation, Streams 1!5. Each stream plus the feed (Stream 0) was fractionated
according to fiber length in a Bauer McNett classifier to compare the fibers at equal
fiber lengths (Bauer McNett screens 16, 30, 50, and 100 mesh were used).
Stream 1 was found to have the highest fiber bonding ability, evaluated as tensile
strength and apparent density of long fiber laboratory sheets. External fibrillation
and collapse resistance index measured in FiberLabTM, an optical measurement
device, also showed this result. Stream 5 was found to have the lowest fiber
bonding ability, with a consecutively falling scale between Stream 1 and Stream 5.
The results from acoustic emission measurements and cross!sectional scanning
electron microscopy analysis concluded the same pattern. The amount of fibers in
each hydrocyclone stream was also regarded as a measure of the fibers’ bonding
ability in each pulp.
The equation for predicted Bonding Indicator (BIN) was calculated by combining,
through linear regression, the collapse resistance index and external fibrillation of
ii
the P16/R30 fractions for Pulps A and B. Predicted Bonding Indicator was found to
correlate well with measured tensile strength. The BIN!equation was then applied
also to the data for Pulps C!E, P16/R30, and Pulp A!E, P30/R50, and predicted
Bonding Indicator showed good correlations with tensile strength also for these
fibers.
From the fiber raw data measured by the FiberLabTM instrument, the BIN!equation
was used for each individual fiber. This made it possible to calculate a BIN!
distribution of the fibers, that is, a distribution of fiber bonding ability.
The thesis also shows how the BIN!distributions of fibers can be derived from
FiberLabTM measurements of the entire pulp without mechanically separating the
fibers by length first, for example in a Bauer McNett classifier. This is of great
importance, as the method is intended for industrial use, and possibly as an online!
method. Hopefully, the BIN!method will become a useful tool for process
evaluations and optimizations in the future.
Keywords: Fiber, mechanical pulp, bonding ability, fiber characterization, Bonding
Indicator, BIN, acoustic emission, hydrocyclone, Fiberlab, collapse resistance,
fibrillation
iii
SAMMANDRAG
Den här studien presenterar en metod för att mäta fördelning av fiberbindning i
mekaniska massor. Metoden hoppas kunna användas industriellt, där i dagsläget
enbart medelvärden används för att mäta fiberbindnings!fördelning, trots råvarans
(fibrernas) morfologiska skillnader.
Fem mekaniska massor (Massa A!E) från olika massaprocesser men från samma
råvara, norsk gran (Picea Abies), har fraktionerats i hydrocykloner med avseende på
fiberbindningsförmåga. Från hydrocyklon!fraktioneringen bildades fem strömmar,
Ström 1!5. Varje ström plus injektet (Ström 0) fraktionerades också med avseende
på fiberlängd i en Bauer McNett för att kunna jämföra fibrerna vid samma
fiberlängd (Bauer McNett silplåtarna 16, 30, 50 och 100 mesh användes).
Fiberbindingsförmåga i den här studien härrör till fiberns flexibilitet och förmåga
att skapa stora kontaktytor med andra fibrer, vilket bidrar till papprets yt! och
styrkeegenskaper.
Ström 1 visade sig ha den högsta fiberbindningsförmågan, utvärderat som
dragstyrka och densitet av långfiberark, samt yttre fibrillering och kollaps resistans
index mätt i den optiska analysatorn FiberLabTM. Akustisk emission och
tvärsnittsanalyser visade samma resultat. Ström 5 visade sig ha den lägsta
fiberbindningsförmågan, med en avtagande skala från Ström 1 till Ström 5.
Andelen fibrer från injektet som gick ut med varje hydrocyklon!ström ansågs
också vara ett mått på fibrernas bindningsförmåga i varje massa.
Genom att kombinera fiberegenskaperna kollaps resistans och yttre fibrillering
från den optiska mätningen på varje fiber genom linjär regression, kunde
Bindnings Indikator (BIN) predikteras. Medelvärdet av Bindnings Indikator för
varje hydrocyklon!ström korrelerar med dragstyrka för långfiber!labark.
Det visade sig att predikterad Bindnings Indikator inte bara fungerade för Massa A
och Massa B P16/R30 fraktionen, som var de fraktioner som användes i den linjära
regressionen, utan även för Massa C!E, P16/R30, och Massa A!E P30/R50 som också
visade goda korrelationer med långfiber!dragstyrka när de sattes in i BIN!formeln.
BIN!formeln användes sedan för varje enskild fiber, i den rådata som levererats
från FiberLabTM. Detta gjorde det möjligt att få en BIN!distribution av fibrerna,
d.v.s. en fördelning av fiberbindningsförmåga.
iv
Den här rapporten visar också hur det går att få BIN!distributioner också från
mätningar på hela massan, för valbara fiberlängder, utan att först mekaniskt
separera massan efter fiberlängd. Det är viktigt, då metoden är tänkt att användas
som en industriell metod, och eventuellt som en online!metod. Förhoppningsvis
kommer BIN!metoden att bli ett användbart verktyg för processutveckling! och
optimering i framtiden.
Nyckelord: Fiber, mekanisk massa, bindningsförmåga, fiber karakterisering,
Bindnings Indikator, BIN, akustisk emission, hydrocyklon, Fiberlab, kollaps
resistans, fibrillering
v
TABLE OF CONTENTS
ABSTRACT........................................................................................................................ii
SAMMANDRAG.............................................................................................................iv
LIST OF PAPERS..........................................................................................................viii
PREFACE..........................................................................................................................xii
1. INTRODUCTION..........................................................................................................1
2. BACKGROUND.............................................................................................................5
2.1 FIBERS...........................................................................................................................5
2.1.1 Fiber morphology and geometry...........................................................................5
2.1.2 Fiber chemistry.....................................................................................................8
2.2 FIBER BONDING...........................................................................................................11
2.2.1 The notation fiber bonding..................................................................................11
2.2.2 Fines....................................................................................................................12
2.3 THE MECHANICAL AND CHEMIMECHANICAL PROCESSES.............................................13
2.3.1. Groundwood pulp (GW).....................................................................................13
2.3.2 Thermomechanical pulp (TMP)..........................................................................14
2.3.3 Chemithermomechanical pulp (CTMP)...............................................................16
2.4 FIBER QUALITY...........................................................................................................18
2.4.1 Measuring fiber quality today.............................................................................18
2.4.2 Fibers in printing paper......................................................................................19
2.4.3 Distribution of fiber bonding ability....................................................................22
3. MATERIALS AND METHODS................................................................................25
3.1 HYDROCYCLONE FRACTIONATION..............................................................................25
3.2 BAUER MCNETT FRACTIONATION...............................................................................27
3.3 PHYSICAL PROPERTIES OF LABORATORY SHEETS.........................................................29
3.4 FIBER GEOMETRY BY CROSS-SECTIONAL SEM-MICROGRAPHS....................................30
3.5 ACOUSTIC EMISSION....................................................................................................31
3.6 MEASUREMENT OF FIBER PROPERTIES IN FIBERLABTM................................................32
3.7 BONDING INDICATOR - BIN........................................................................................34
4. RESULTS AND DISCUSSION.................................................................................35
4.1 HYDROCYCLONE FRACTIONATION – WEIGHT PERCENT PER STREAM...........................35
4.2 FRACTIONATION BY FIBER LENGTH IN THE BAUER MCNETT CLASSIFIER....................37
vi
4.3 PHYSICAL PROPERTIES OF LABORATORY SHEETS.........................................................40
4.4 FIBER GEOMETRY BY CROSS-SECTIONAL SEM-MICROGRAPHS....................................43
4.5 ACOUSTIC EMISSION....................................................................................................45
4.6 MEASUREMENT OF FIBER PROPERTIES IN FIBERLABTM................................................48
4.6.1 External fibrillation.............................................................................................48
4.6.2 Fiber wall thickness............................................................................................49
4.6.3 Fiber width..........................................................................................................51
4.6.4 Collapse resistance index (CRI)..........................................................................52
4.7 BONDING INDICATOR – BIN........................................................................................53
4.7.1 Prediction of average Bonding Indicator............................................................53
4.7.2 Distributions of Bonding Indicator.....................................................................55
4.7.4 Identifying all fibers in the BIN-distributions......................................................58
4.7.5 BIN-distributions for fibers – without fiber length fractionation........................59
5. FINAL DISCUSSION..................................................................................................63
6. CONCLUSIONS...........................................................................................................65
7. FUTURE WORK...........................................................................................................65
8. ACKNOWLEDGEMENTS.........................................................................................67
9. REFERENCES...............................................................................................................71
APPENDIX........................................................................................................................75
APPENDIX 1. PHYSICAL PARAMETERS OF LONG FIBER LABORATORY SHEETS....................75
APPENDIX 2. DISTRIBUTIONS OF FIBER PROPERTIES FROM FIBERLABTM...........................79
APPENDIX 3. BIN-DISTRIBUTIONS (BONDING INDICATOR)...............................................82
BIN-distributions from whole pulps for fiber length intervals.....................................83
Average BIN for fiber length intervals.........................................................................85
Amount negative BIN-fibers (low bonding fibers) for fiber length intervals................85
APPENDIX 4. SEM-IMAGES...............................................................................................87
Cross-sectional micrographs from fiberlength fraction P16/R30................................87
Long fiber laboratory sheets, fiberlength fraction P16/R30........................................88
vii
LIST OF PAPERS
This thesis is mainly based on the following two papers, herein referred to by their
Roman numerals:
Paper I Ways to measure the bonding ability distribution of fibers in
mechanical pulps
Reyier, S., Ferritsius, O., Shagaev, O.
Manuscript, accepted for publication in TAPPI Journal (2008)
Paper II BIN – a method of measuring the distribution of Bonding
Indicator of fibers in mechanical pulp furnishes
Reyier, S., Ferritsius, O.
Manuscript, to be submitted to Nordic Pulp and Paper Research
Journal (2008)
AUTHOR’S CONTRIBUTION TO THE REPORTS
The author’s contributions to the papers in the thesis are as follows:
Paper I Experimental work, interpretation of results together with Olof
Ferritsius; paper written together with Olof Ferritsius and Oleg
Shagaev. Results regarding acoustic emission measurements were
interpreted together with professor Per Gradin, Mid Sweden
University, and Anders Hansson, Stora Enso Research Centre Falun.
Paper II Experimental work, interpretation of results together with Olof
Ferritsius; paper written together with Olof Ferritsius.
viii
RELATED MATERIAL
Results related to this work have been published or presented at international
conferences as follows:
Ways to measure the bonding ability distribution of fibers in mechanical pulps
Reyier, S., Ferritsius, O., Shagaev, O.
Proceedings of International Mechanical Pulping Conference, Minneapolis, USA,
May 6!9, 2007, CD!ROM
Some aspects of fiber bonding ability in mechanical pulps
Reyier, S., Ferritsius, O., Shagaev, O.
Presented at PIRA International Refining & Mechanical Pulping Conference,
Arlanda, Sweden, December 12!13, 2007, CD!ROM
BIN ! A method to measure the distribution of fiber bonding ability in
mechanical pulps
Reyier, S., Ferritsius, O.
Presented and extended abstract, 6th Fundamental Pulp Research Seminar, Espoo,
Finland, May 21!22, 2008
ix
Description:this paper refers to the mechanical fiber's flexibility and ability to form large distribution of the fibers, that is, a distribution of fiber bonding ability.
