FuBio seminar 27.8.2013

1. Hot water extraction of wood
and extract purification
FuBio JR2 WP1
Petri Kilpeläinen, Johanna Tanner
Finnish Forest Research Institute

2. FuBio JR2
Research partners
• Research organisations
– Aalto University, Aalto
– Finnish Forest Research Institute, Metla
– Lappeenranta University of Technology, LUT
– University of Helsinki, UHe
– University of Jyväskylä, UJy
– VTT Technical Research Centre of Finland, VTT
– Åbo Akademi University, ÅA
• Industrial partners
– Andritz
– Kemira
– Metsä Group
– Stora Enso
– UPM-Kymmene

3. FuBio JR2
The aim
•To get fundamental knowledge of pressurized hot
water extraction (PHWE)
•To extract hemicellulose and lignin from sawdust
̶ To produce polymeric, water soluble
hemicellulose
̶ Lignin as by-product
̶ Extracted sawdust is processed to novel pulps

4. FuBio JR2
Rawmaterials and pre-treatment
Separation and purification
Products
Refined products
Wood
- Spruce sawdust
- Birch sawdust
PHWE
- Lab scale, METLA, ÅA
- Pilot scale, METLA, VTT
- Supercritical, Aalto
Delignification
- Lab scale, Ujy
- Pilot scale,
VTT
Concentration
- Ultrafiltration, LUT
Hydrolysis
- Enzymatic, UHe
- Acid, ÅA
Purification
- EtOH precipitation, LUT,
METLA
- Oxidation, ÅA
Acidification
- METLA
Monosugars High Mw
hemicelluloses
Lignin
Fuels Barriers Composites Pulp
Extract
High MwLow Mw
Black liquor

5. FuBio JR2
METLA
ÅA
VTT
Aalto
Extraction temperatures
• Viscosity, diffusivity and dieletric constant of water changes at higher
temperatures
• pH scale changes as pKw value of water changes
Gas

6. FuBio JR2
Lab scale

7. FuBio JR2
Batch extraction of fine spruce
sawdust
• Accelerated solvent extraction (ASE)
350, Zr-type cell
• Temperature: 150-180 C
• Solvent: distilled water
• Liquor/Wood ca 4/1
• Pressure: 10 MPa
• Fine fraction 0.05-0.1 mm of ground
spruce sapwood

8. FuBio JR2
TDS of extracts obtained at different temperatures
(particle size 0.25-1.0 mm vs fine fraction 0.05-0.1
mm)
Ethanol precipitated polymeric GGM from extracts
obtained at different temperatures (particle size
0.25-1.0 mm vs fine fraction 0.05-0.1 mm)
Possible to obtain polymeric hemicellulose
at lower temperature with fine fraction
180 C Max yield

9. FuBio JR2
PHW flow-through extraction of
birch sawdust with pH buffer
• 10 g a.d. of birch sawdust
• 50 ml extraction vessel
• Temperatures 160-180 C
• 50-70 Bar
• 30 min extraction
• 4 ml/min flow rate
• 0.1 M acetate buffer
• pH 4.0, 4.2 and 4.6

10. FuBio JR2
Molar mass of xylan increases with
(pH 4.0) buffer
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
24 29 34 39 44
RID
Retention time, min
NO BUFFER
160°C
Mw 18.8 kDa
170°C
Mw 2.1 kDa
180°C
Mw 1.1 kDa
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
24 29 34 39 44
RID
Retention time, min
BUFFER
160°C
Mw 14.2 kDa
170°C
Mw 4.8 kDa
180°C
Mw 3.9kDa
Decreasing molar mass Decreasing molar mass

11. FuBio JR2
Oxygen-alkali delignification of PHW
extracted sawdust
• Pulp yields were lower after PHWE combined with oxygen-alkali
cook
• Less lignin was dissolved since some lignin was dissolved
during PHWE
0
10
20
30
40
50
60
70
80
30 60 90 120 150Pulpyield,%oforiginaldry
wood Cooking time, minutes
Spruce sawdust
PHW extracted sawdust
• Spruce and birch PHW
extraction residues were
cooked for 30-150 min at
170 C
• Liquor to wood ratio
5L/kg

12. FuBio JR2
Supercritical water treatment
• Target: Dissolution of crystalline cellulose in near- and supercritical water
• Produce cello-oligomers from cellulose
• Minimizing sugar losses by applying a short reaction time
Cellulose
Dissolved
poly- and
oligomers
Glucose
Degradation
products

13. FuBio JR2
Cellulose dissolution in subcritical
and supercritical water
Short reaction time
t < 1 s
Long reaction time
t > 1 s
Microcrystalline cellulose (MCC), Pre-hydrolyzed Kraft pulp (PHK), Alkaline treated (mercerized)
Cellulose precipitate after 0.2 s treatment

14. FuBio JR2
Modeling

15. FuBio JR2
Modeling of PHWE
• Objective: Develop a model for the
degradation of birch in a percolation
reactor.
• Previous PHWE study for batch reactor
(Borrega et al. 1) .
• Models were fitted to describe the
degradation of lignin, xylan and
glucan.
• How do the parameters obtained from
the batch experiments fit the new
data from percolation cooks?
Schematic diagram of the flow-through
percolation reactor and associated
elements used for the hot water
extractions of wood.
1. Borrega, M., Nieminen, K., and Sixta, H. (2011). “Degradation kinetics of the main carbohydrates in birch wood during hot
water extraction in a batch reactor at elevated temperatures,” Biores. Technol. 102(22), 10724-10732.

16. FuBio JR2
Model
• It is assumed that the hot liquor
moves as a plug flow
• Initially the reactor only partly filled
with hot liquor – the reactions occur
only in the hot section.
• Once a wood component has been
dissolved, it stays in the reactor only
for a short time before it is washed
out and cooled down – less further
reaction products than in a batch
reactor.
• Partial differential equations describe
the time developments of the various
products 0 10 20 30 40 50 60
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
%o.d.w
Time (min)
0 50 100 150 200
0
1
2
3
4
5
Glucooligosacharides (GOS)
Glucose
Hydroxymethylfurfural (HMF)
Other degradation products (Dp)
%o.d.w
Time (min)
200 C
Batch
Flow-through
Flow rate 100
ml/min

17. FuBio JR2
Average Mw GGM content of the PHWE extract mg/g
Temperature ( C)
Flowrate(l/min)
1
2
3
4
6
5
150 160 170 180155 165 175 185 150 160 170 180155 165 175 185
Temperature ( C)
1
2
3
4
6
5
14
6
250
10
50
150
Modeling flow-through PHWE of spruce sawdust
utilizing Modde (partial least squares method)
• A combination of low PHWE temperature and low flow rate dissolves highest molecular mass GGM, but with lower yield
• The model can be used to choose process conditions for PHWE in order to produce desired GGM properties

18. FuBio JR2
From lab to pilot scale

19. FuBio JR2
Example of stepwise batch PHWE process of spruce
sawdust in a semi-pilot scale (30 l vessel) extraction
0
1
2
3
4
5
6
7
8
9
10
160 °C/40 min 170 °C/60 min 180 °C/3 h washing at
50 °C/30 min
AverageMwofspruce
sawdustextract(kDa)
• Stepwise PHWE dissolved GGM with high average Mw in the 1st step. The Mw was clearly
decreased in the 2nd and 3rd steps.
• PHWE processes in VTT’s 30 l extraction vessel are reproducible, when looking at e.g. average
molecular mass of the extracts in the first two steps of the two separate processes
2-step PHWE
3-step PHWE

20. FuBio JR2
Pilot scale (300 L) extraction
vessel

21. FuBio JR2
Results Spruce Birch
Sawdust weight o.d. [kg] 53 kg 73 kg
Time when collected [min] 15 – 30 min 30 – 45 min 15 – 35 min 35 – 55 min
pH 4.4 3.7 3.9 3.8
Hemicellulose yield [wt%] 4 wt% 7 wt% 3 wt% 6 wt%
Mw [kDa] 13 kDa 8 kDa 14 kDa 8 kDa
PHWE flow-trough extraction
examples in pilot scale
• Spruce at 170 C
• Birch at 160 C with pH 4.0 buffer
– pH stabilization during extraction
• Extracts to ultrafiltration and purification

22. FuBio JR2
Lignin from pilot scale extraction
•Extracted sawdust was cooked with
soda-aq to remove lignin
•Solution was acidified to precipitate
sulfur free lignin
•Lignin was purified to remove
inorganics
•Purified lignin was used to make
biocomposites

23. FuBio JR2
Separation and purification of
extracts

24. FuBio JR2
Recovery of high molar mass
hemicelluloses in pilot scale
• High shear rate CR-filters
• Commercial, hydrophilic 10 kDa regenerated cellulose membrane (Alfa Laval)
• 60 C, 2 bar, rotor velocity 9.5-13.8 m/s
CR-350
Feed
Permeate
Concentrate
Filter cassette
Drainage support
Membrane
Feed
Permeate
Concentrate
Filter cassette
Drainage support
Membrane
From Metso Paper
Operation principle:

25. FuBio JR2
Ultrafiltrations can be done continuously
without losing filtration capacity

26. FuBio JR2
Extract can be concentrated and molar mass (Mw) of
hemicellulose increases during extraction
• Possible to achieve the TDS
and Mw of hemicellulose
required for film
manufacturing
• Increase in TDS content and
Mw of hemicellulose have a
clear effect on capacity
• Filtration capacity with
spruce extracts higher than
with birch extracts
• Birch extracts need further
purification to obtain better
filtration results
Three different birch extract filtrations

27. FuBio JR2
Summary
•Fundamental knowledge obtained to up-scale
system from lab to pilot scale
•Possible to extract polymeric, water-soluble
hemicellulose from spruce and birch
•Produced lignin can be utilized to make
biocomposites
•Purification and concentration of hemicelluloses
can be done continuously with ultrafiltration

28. FuBio JR2
Acknowledgements
Aalto
Lasse Tolonen
Marc Borreca
Herbert Sixta
Metla
Petri Kilpeläinen
Sanna Hautala
Johanna Tanner
Veikko Kitunen
Olli Byman
Teemu Tikkanen
Zhiqiang Li
Kaisu Leppänen
Hannu Ilvesniemi
LUT
Mari Kallioinen
Elsi Koivula
Tuomas Nevalainen
Mika Mänttäri
Uhe
Maija Tenkanen
Ujy
Joni Lehto
Raimo Alén
VTT
Marjatta Kleen
Tarja Tamminen
ÅA
Andrey Pranovich
Risto Korpinen
Jan-Erik Raitanen
Chunlin Xu
Jarl Hemming
Jens Krogell
Henrik Grénman
Tapio Salmi
Stefan Willför
Kemira
Marcus Lillandt