FIBIC FuBio JR2 programme report

Ohjelmatunnukset
Future Biorefinery Joint Research 2
Programme Report 2011-2014

13
Ohjelmatunnukset
Future Biorefinery Joint Research 2
Programme Report 2011-2014

FUBIO JR2 PROGRAMME REPORT
Copyright Finnish Bioeconomy Cluster FIBIC 2014. All rights reserved.
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ISBN 978-952-67969-6-3 (paperback)
ISBN 978-952-67969-7-0 (PDF)
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Coverpage: TOC graphic image from Parviainen, A., King, A. W. T., Mutikainen, I., Hummel, M., Selg,
C., Hauru, L. K. J., Sixta, H., Kilpeläinen, I.: Predicting cellulose solvating capabilities of acid base
conjugate ionic liquids. ChemSusChem. 2013. 6. 2161-2169. Copyright Wiley-VCH Verlag GmbH & Co.
KGaA. Reproduced with permission.
Page 32: Photo by Metla / Erkki Oksanen
CONTENT
Foreword .........................................................................................................................................................5
World-leading knowledge platforms for wood-based biorefineries...........................................6
Introduction...................................................................................................................................................10
Modelling and techno-economic evaluation of biorefinery concepts.....................................14
New solutions for biomass fractionation .........................................................................................32
Ionic liquids for wood fractionation..................................................................................................... 52
Hydroxy acids (and other acids) from black liquor ........................................................................ 72
Biological effects of wood-based extracts and compounds in models of
human disease............................................................................................................................................88
Thermoplastic lignin and reinforcing cellulose fiber composites for advanced
biocomposite applications....................................................................................................................104
Biorefinery products ...............................................................................................................................122

FUBIO JR2 PROGRAMME REPORT 5
FOREWORD
The bioeconomy has fast developed as one of the most relevant platforms for
business and environmental sustainability today. In parallel, Finland’s centuries-rich
forest industry is undergoing radical renewal. Coupling leading-edge wood and paper
products expertise with milestone advances in technology, research competence
and knowledge, the industry is unlocking vast potential for new products and new
integrated processes – and turning its most ambitious targets and concepts into
realistic business opportunities.
Along with the renaissance of wood use in construction, design and mechanical
industry, environmentally friendly wood-derived chemicals are increasingly replacing
conventional oil-based materials. The wood raw material for chemical pulping contains
numerous components in addition to cellulose that are currently burned for energy
recovery. Intelligent process solutions drawing on new knowledge and Finland’s
common logistics, energy and technology platform are now enabling the separation
and generation of highly value-added products from this valuable bioresource. These
new products can be used to enhance existing paper and board products or applied in
new alternative business areas.
The forest industry has been the backbone of the Finnish economy throughout its
history. Today, the urgent need to find innovative applications for new forest-based
products is two-fold: the decline in the printing and writing paper sector and the fight
to find new sustainable business based on Finland’s staple renewable resource –
wood. The work done in the FuBio JR2 programme brings these efforts a significant
step forward by opening exciting development opportunities and lighting the path
towards innovative and sustainable industry renewal.
The five-year EUR 50 million FuBio JR2 programme, a continuation of FuBio 1,
represents a dedicated effort and investment by the Finnish Bioeconomy Cluster –
joint research company FIBIC Ltd. The programme lays a solid foundation for building
competence in bioeconomy research and for business creation. It also significantly
enhances networking between industry and the research community as well as joint
understanding of the research challenges and needs of the future.
Mika Hyrylä
UPM-Kymmene Oyj
Chairperson, FuBio Joint Research 2 Programme Management Group

FUBIO JR2 PROGRAMME REPORT6
WORLD-LEADING
KNOWLEDGE PLATFORMS
FOR WOOD-BASED
BIOREFINERIES
The renewal of the forest industry and creation of new businesses
are essential prerequisites for the future success of the Finnish pulp
and paper industry as part of a sustainable, bio-based economy.
In the second FuBio Joint Research programme,
companies and research organizations
have jointly developed globally competitive
knowledge platforms within the field of wood-
based biorefinery research and development,
by creating new value chains for refining novel
materials and chemicals.
A wide range of Finnish forest cluster
companies have actively participated in FuBio
JR2. In the following chapters the companies
highlighttheresultsachievedintheprogramme.
Great new potential in ionic liquids
In the FuBio Joint Research programmes 1 and
2 over 100 new ionic liquids were synthesized.
The best ones show great potential for
certain applications studied in another FIBIC
programme, FuBio Cellulose.
The FuBio JR 2 research work on ionic liquids
is expected to be invaluable for the future of
the Finnish forest industry and will probably
have a major impact for the renewal of the
biorefinery sector. Ionic liquids may even be a
game changer for future biorefineries.
Although the majority of the companies that
have participated in the FuBio JR2 programme
regard ionic liquids as extremely attractive
and promising, they admit that some aspects
need more study and development before
industrial-scale utilization.
The FuBio programmes have built a
competence platform on ionic liquids and led to
the creation of key research teams. However,
new skills are still needed, and consequently
different consortia will launch more focused
programmes and projects in the near future,
to devise industrial applications.
The development of new ionic liquids has
created great potential for new production
processes in wood-based value chains. The
same knowledge is applicable to other areas
as well.
Mikael Hannus, Stora Enso:
“Before we have industrial applications in use,
a lot of development work is needed. In general,
breakthrough technologies are not created
overnight and are developed at high risk.
The Fibic framework is a functional environment
for this kind of research and development.”

Lignin and hemicellulose – raw materials
for future bio-based business
The research has given strong indications
that residues from pulp and paper production,
such as lignin and hemicellulose, will have the
greatest impact in the production of novel bio-
based products.
The Fubio JR2 programme has created new
insight into wood chemistry and promoted
broad competence in hemicellulose separation
technologies. Specifically it has improved
understanding of the phenomena of hot water
extraction of hemicelluloses.
The applications foreseen are now more realistic
than at the beginning of the programme.
However, the separation processes will become
more feasible when methods have been
developed for the utilization of all possible
fractions.
One of the main research interests in
the FuBio JR2 programme was lignin and
its potential as a component in bio-based
composites. The properties and production
technologies of kraft lignin fibre composites
were studied, and the teams were capable of
developing and producing prototype products.
The demo trials performed by composite
manufacturers gave excellent feedback that
can be utilized in further development.
Kari Saari, Kemira:
“We regard new sustainable polymeric raw
materials, such as hemicellulose, as potential
future raw materials that can be substitutes for
fossil-based ones in use today.”
Several alternatives for bio-based
barrier materials
The Fubio JR2 programme evaluated the
applicability of several bio-based alternatives
in barrier applications. Alkali-extracted
xylan has been identified as one of the new
barrier materials with the greatest potential,
and its performance has been successfully
demonstrated at pilot scale.
As a barrier material xylan has many
advantages: its bio-content is quite high, its
availability is good because the pulp and paper
industryisthemainsupplieroftherawmaterial,
and the production process is workable. The
end product has also been shown to have
promising converting properties.
The issues that still need to be solved are the
barrier capability against oxygen, and deeper
cost calculations of the production process, as
well as detailed study on implementation in
industrial applications.
The programme helped in understanding
the possibilities, but also the challenges, in
the use of biopolymers. At the same time, it
created a framework for performing analyses.
Pirkko Liias, Metsä Fibre:
“The bio-barrier study has generated knowhow
about the possibilities of different derivatives,
helping to decide which ones ought to be ruled
out and which should be taken for further
development.”

Networking created more value
In the work that studied ionic liquids, lignin
composites, bio-barriers, mouldable fibre
products, new filters or medicinal products,
networking created more value than if the
research teams had been working alone. All
in all, networking is a key attribute of all Fibic
programmes.
One of the participants noted that the best
outcomes were achieved in the teams that
worked openly and dynamically. Dialogue
between representatives of the research
and industrial partners has been extremely
important for the successful results of the
programme.
The programme was divided into work
packages, each with an industrial partner
represented in the steering group and in the
technical meetings. This structure ensured that
the programme was immediately focused in the
right direction. In setting the study, important
issues such as regulatory compliance and
scale-up of the processes were raised at an
early stage.
Mika Hyrylä, UPM-Kymmene:
“The wide international and competent network
also made it possible to test end-products, such
as composites.”
The work goes on
The research of the FuBio JR2 programme
was precommercial. In order to achieve
industrial applications, further development
work is needed. Many companies have already
launched internal projects to continue the work.
The techno-commercial models created in
the programme broadened the scope of the
work with commercial viewpoints, and will act
as an excellent tool in further research.
Apart from pulp and paper companies,
several technology suppliers participated
in the programme. Through the FuBio JR2
knowledge platforms they have been able to
find suitable partners.
Jussi Piira, Andritz:
“The programme has provided us with an
outlook for future processes. The new processes
require intensive development of technologies,
which is why it is essential for a technology
supplier to be part of the work as early as
possible.”

INTRODUCTION
The Finnish forest industry has evolved
over the centuries through several key
phases, spanning from early tar production
and sawmilling to modern pulp and paper
making. Today, the production of wood-based
chemicals – once a focal point of the industry
until its eclipse by low-cost, high-performing
chemicals and materials of the petrochemical
boom – is seeing a resurgence. Biorefinery
has now emerged as the next branch in the
evolution of end uses for Finland’s abundant
forest biomass.
Future Biorefinery (FuBio) is one of the strategic
focus areas of the Finnish Bioeconomy Cluster
FIBIC (formerly Forestcluster Ltd). The main
objective of FuBio research is to establish
in Finland globally competitive knowledge
platforms for the renewal of the existing forest
industry and the creation of new business. The
FuBio research path is expected to create new
value chains in which biomass-based materials
and chemicals are used in substantial, global
markets. The potential markets of focus are
both well-known to the forest industry (e.g.
fibre-based packaging) as well as essentially
new, such as textiles, nonwovens, polymers,
resins and thermo-formable composites.
FuBio research was initiated in March 2009
with the launch of the first two-year joint
research programme. In 2011 FuBio was further
split into two separate programmes: ‘Products
from Dissolved Cellulose’ (FuBio Cellulose) and,
the focus of this programme report, ‘Future
Biorefinery Joint Research 2’ (FuBio JR2).
At the time of planning the FuBio programme,
national and international attention within the
field was almost exclusively focused on biofuels.
It was therefore decided after careful analysis
to exclude biofuels from the FuBio theme. The
largest Finnish research efforts in biorefinery
at the time included the BioRefine programme
of the Finnish Funding Agency for Innovation
(Tekes) and various Technical Research Centre
of Finland (VTT) programmes. These were also
taken into account and relevant programme
interfaces were established.
Creating new biorefinery value chains requires
deep understanding of biomass structures. New
processing technologies must be developed
hand-in-hand with the design of new biorefinery
concepts, including their respective value chains.
Understanding the markets and having the
freedom to-operate in them are essential. The
first steps towards future industrial partnerships
must also be taken.
"The main objective of FuBio research is to establish
in Finland globally competitive knowledge platforms
for the renewal of the existing forest industry and the
creation of new business."

In addition to the main objectives defined
above, FuBio also aimed at achieving a broader
national impact by:
• Improving industry awareness of new wood
biorefinery opportunities.
• Establishing new ways and levels of
cooperation within R&D in Finland.
• Shortening the time from idea to innovation
through effective collaboration.
• Establishing strategic, international R&D
partnerships.
• Maintaining and improving Finnish
biorefinery R&D facilities through lab and
early-stage piloting/initial material demos.
• Educating a new generation of researchers
(M.Sc. and D.Sc./PhD) for the biorefinery field.
The scientific publication output of the FuBio
programme has increased as a result of
FuBio JR2, bringing greater global visibility
for the programme and promoting the open
innovation strategy chosen for FuBio.
Figure 1. The six target markets of FuBio. Regenerated fibre and chemicals was targeted by the FuBio
Cellulose programme, the remaining markets by FuBio JR2.
The globally competitive knowledge platforms
targeted by the programme, as mentioned
above, specifically include:
• New biomass fractionation methods,
especially based on ionic liquids and hot
water extraction,
• Advanced separation technologies suitable
for separation of biomass fractions as well
as hydroxy acids from black liquor,
• Chemical and biotechnical modification/
up-grading of biomass fractions to natural
polymers, extractives, hydroxy acids, etc.,
• Application of wood fractions as structural
composites, hydroxy acid products, new
board packaging concepts, reactive/active
filter materials and health applications,
• Modelling, especially techno-economical
evaluation of immature biorefinery concepts,
• Biomass characterization and analysis, and
• Initial process piloting and/or material
prototype production
As a summary, Figure 1 shows the key
application areas of the FuBio research theme.

Programme portfolio
FuBio JR2 was divided into eight Work Packages
(WPs). The use of wood fractionation alongside
a pulp mill (WP1 Hot water extraction) or even
to replace a pulp mill (WP2 Novel biomass
fractionation) was examined. Possible future
products were identified in the area of advanced
biocomposites (WP3), packaging (WP4), filters
(WP4) and health applications (WP5) as well as
for hydroxy acids separated from black liquor
(WP6). In modelling and piloting (WP7) the focus
was targeted at improving models for new
processes and techno-economical evaluation
of selected FuBio product cases. The main
goals and results of the work packages are
presented in the following chapters.
Management of the programme
The FuBio JR2 programme was led by
a Management Group (MG) including
representatives from industry and academia.
Themainresponsibilityforday-to-dayexecution
was with the Programme Manager (PM). Each
work package had a WP Leader and one or
several Industrial Tutors. The industrial tutors’
role was to bring an industrial perspective to
the work packages, while the WP leaders were
responsible for day-to-day management of
the WP. The work packages were divided into
tasks and subtasks, and some of the tasks were
assigned specific Task Leaders. The PM and WP
leaders formed the execution Core Team.
The main task of the management group was to
supervise the progress of the programme with
respect to the objectives and the programme
plan. The management group followed the
work progress of specified issues through a
gate system and WP results and achievements
through WP presentations in management
meetings and through Programme Milestones
and Deliverable reports. The WP steering
groups together with the industrial tutors
assisted the WP leaders in focussing the work
as needed.
The Management Group had the following
members:
• Mika Hyrylä, UPM, Chairman (Eeva
Jernström until December 2012)
• Mikael Hannus, Stora Enso
• Johannes Heiskanen, Novoplastik
• Seppo Hiljanen, Valmet
• Annaleena Kokko, VTT (Niklas von Weymarn
until August 2012), Programme Manager
• Markku Leskelä, FIBIC (Lars Gädda until
April 2012)
• Pirkko Liias, Metsä Fibre
• Risto Lilleberg, Metsäliitto Group
• Erkki Peltonen, Myllykoski (until September
2011)
• Jussi Piira, Andritz (Paterson McKeough
until May 2013)
• Kari Saari, Kemira
• Lauri Verkasalo, Metsä Board (Ari Kiviranta
until September 2011)
• Stefan Willför, Åbo Akademi University,
Scientific Coordinator
• Erja Ämmälahti, Tekes
Dissemination of the FuBio JR2 programme
results has been achieved through a variety of
channels. The main channel for the distribution
of results, reports and meeting minutes has
been the FIBIC research portal, accessible to
FuBio JR2 programme partners, and the FIBIC
website (http://fibic.fi/programmes/fubio-jr2-2).
Additionally, results have been extensively
shared in both external (public) and internal
seminars, and demonstration samples and
related posters have been displayed at SHOK
(Finnish strategic centres for science, technology
and innovation) summits and Tekes events, as
well as in programme overviews presented at
FIBIC seminars and international conferences.

Participants and international
cooperation
The three-year joint research programme on
future biorefinery had a total of 22 industrial
and research partners, bringing multi-faceted
knowledge and competence to the programme.
Industrial partners:
• Andritz
• FIBIC
• Kemira
• Metsäliitto Group
• Metsä Fibre
• Metsä Board
• Myllykoski
• Novoplastik
• Stora Enso
• UPM-Kymmene
• Valmet
Research partners:
• Aalto University
• Lappeenranta University of Technology
• Finnish Forest Research Institute, Metla
• Tampere University of Technology
• University of Helsinki
• University of Jyväskylä
• University of Tampere
• University of Turku
• University of Oulu
• VTT Technical Research Centre of Finland
• Åbo Akademi University
International cooperation in Future Biorefinery
Joint Research 2 was achieved through
researcher exchange, with more than 15
researchers visiting over a dozen universities
and research institutes in Portugal, Venezuela,
Sweden, Spain, France, Germany and Austria
for more than 40 person-months.
The programme participants have also
actively presented the programme results
in international conferences, COST action
meetings and workshops. International
seminars have also been arranged by the
programme, especially in WP2 in the area of
ionic liquids, which attracted high international
interest and was highly commended by the
programme partners. In order to demonstrate
the increased competence resulting from
the programme the main results have been
published in peer-reviewed journals, with
over 80 publications to date and close to 40
currently submitted for publication. Over 20
Master’s theses and five PhD thesis have been
written by students fully or partly financed
by FuBio programmes, with a further 10 PhD
students expected to defend their thesis
within the coming year.

14
MODELLING AND
TECHNO-ECONOMIC
EVALUATION OF
BIOREFINERY
CONCEPTS
CONTACT PERSON – Work Package 7 leader Eemeli Hytönen, eemeli.hytonen@vtt.fi
Aalto University: Moshood Abdulwahab, Waqar Ahmad, Ville Alopaeus, Kaj Jakobsson,
Susanna Kuitunen, Zheng Liu, Kaarlo Nieminen, Juha Visuri
Andritz: Paterson McKeough
GloCell: Jari Aittakari, Hanna Kalanne, Juhani Lehtonen, Pirita Mikkanen, Jukka Seppänen
Kemira: Marcus Lillandt, Anna-Maija Saariaho
Lappeenranta University of Technology: Mari Kallioinen, Elsi Koivula, Jarno Kohonen,
Maaret Paakkunainen, Satu-Pia Reinikainen
Metsä Fibre: Esko Turunen
Pöyry Management Consulting: Carina Björnström, Henna Jääskeläinen, Jesse Kautto,
Anna Saarentaus, Katja Salmenkivi, Juulia Rouhiainen, Petri Vasara
Stora Enso: Kalle Ekman
University of Oulu: Eva Pongracz, Paula Saavalainen
UPM-Kymmene: Mika Hyrylä, Seppo Virtanen
Valmet: Seppo Hiljanen, Päivi Uusitalo
VTT Technical Research Centre of Finland: Tuomas Helin, Catharina Hohenthal, Timo Kaljunen,
Marjo Kauppi, Marjatta Kleen, Vesa Kunnari, Juha Leppävuori, Marja Nappa, Lotta Sorsamäki
FUBIO JR2 PROGRAMME REPORT

ABSTRACT
In Future Biorefinery Joint Research 2 (FuBio JR2), modelling was used at different levels
of biorefinery technology development to support research and to indicate the industrial
feasibility of the novel technologies developed in the programme. The focus was on i)
phenomena-based modelling and statistical experimental design of hot water extraction
of hemicelluloses from wood, ii) early-stage techno-economic modelling of future
biorefinery concepts based on the wood fractionation technologies and novel biorefinery
products developed in the programme, and iii) process modelling and simulation, and
quantitative economic and qualitative opportunity analysis of selected promising future
biorefinery concepts.
Two new models were developed for pressurized hot water extraction (PHWE). The
new models are more advanced and comprehensive than the previous PHWE models
presented in the literature, enabling more detailed analysis of the phenomena involved
and optimization of the process.
Several process concepts were designed and evaluated. Conceptual-level techno-
economic screening of some 100 concepts as well as more detailed modelling of five
process and product development ideas, including hot water extraction, ionic liquids
wood fractionation, black liquor hydroxy acids separation, bio-barriers and bio-
composites, were conducted. New methods for process integration, market entry and
comprehensive risk assessment were also developed and successfully demonstrated
along with the evaluation of several selected concepts in detail. The work was done in
close collaboration with research and industry partners.
Keywords:
biorefinery concepts, modelling, physico-chemical modelling, techno-economic modelling

1. Background
Different knowledge and data are needed at
different technology development stages.
For example, initial concept analysis requires
a systematic approach and modelling of
overall production systems, but no detailed
data is needed on the process conditions or
phenomena involved in the different processing
steps. In contrast, when scaling up a process
step and designing its process and process
equipment, understanding of the specific
phenomena involved in that step in the process
is needed, whereas modelling of the overall
production system is not necessarily required.
Therefore the problem statement and scope
of modelling varies significantly during the
technology development.
Many modelling methods and tools related to
the fields of research of the Future Biorefinery
Joint Research 2 programme have been
previously developed. For example, a number
of existing chemical process design methods
and simulation tools are applicable to the FuBio
JR2 context and these have been combined
in earlier FIBIC programmes as a toolbox for
quantitative and qualitative concept evaluation
for aiding decision making. In addition,
simulation tools for modelling pulping and
bleaching physico-chemical phenomena have
also been developed. These state-of-the-art
tools required further modifications to meet the
targets of the current programme.
Various process and product ideas were
studied and developed in FuBio JR2. To steer
future research efforts and estimate the future
business potential of these pre-commercial
stage R&D ideas, production concepts were
designed, screened and evaluated and tools
for modelling the phenomena taking place in
the studied wood fractionation processes were
developed.
2. Objective
The overall objective of the modelling work was
to provide more knowledge and data on the
technologies developed in the programme in
order to support decision making.
The specific goals set for physico-chemical
modellingwere:1)developchipandreactorscale
models for pressurized hot water extraction
(PHWE), and 2) develop a comprehensive
model for PHWE chemistry (especially model
the evolution of the hemicelluloses’ molecular
weight distribution).
The specific goals set for techno-economic
modelling were: 1) to create new biorefinery
concepts and evaluate their sustainability, and
2) to develop modelling tools and apply them
to support the technology development work.
3. Research Approach
3.1 Physico-chemical modelling of hot
water extraction
Chip and reactor scale modelling of PHWE
For the modelling of simplified PHWE chemistry
for chip and reactor model development,
experimental data from PHWE of coarse birch
(Betula pendula) sawdust in a batch reactor
was collected. A high liquid-to-wood ratio
was selected to minimize limitations on the
solubility of the extracted wood components.
Experiments were conducted at different
temperatures and with different durations.
After each experiment the wood residue was
collected from the reactor and the yield of
the components was measured. Based on
this data the appropriate stoichiometry and
kinetic parameters of the reactions leading
to delignification and condensation of lignin
as well as carbohydrate degradation were
estimated. A model combining the reaction

Figure 1. Overall techno-economic analysis approach.
kinetics with the diffusion in a wood particle
was constructed in Matlab. The differential
equation associated with the model was solved
numerically using the finite difference method
and the PDE tools available in Matlab. The
model enables a simulation of the reaction
product evolution at chip level during PHWE.
Comsol Multiphysics was chosen for simulating
the progress of PHWE at the reactor level, as
the software includes tools for describing flow
and heat transfer in porous media and enables
equations for the reaction kinetics to be added.
Comprehensive modelling of PHWE chemistry
In order to be able to build the physico-
chemical model, understanding was needed
of which properties and chemical constituents
of wood are relevant to the modelling of hot
water extraction as well as how the chemical
constituents react and dissolve from wood into
the extract in hot water extraction conditions.
Both lignin and carbohydrate reactions are
considered and, since several reactions are
catalysed by hydrogen ions, special attention is
paid to accurate modelling of pH evolution.
In the modelling, changes in the molecular
weight distribution of the hemicellulose
polymers are considered by describing chain
lengths as discrete size categories where the
rate of change of number concentrations for
various polymer chain lengths is calculated.
A high-order numerical method capable of
extremely accurate prediction of integral
properties of the distribution is applied. Other
parameters related to physico-chemical
parameters of the components included in
the modelling of hot water extraction are then
estimated and gathered from public sources.
The aim was to collect as many as possible
models and parameters from the literature.
Some of the model parameters were regressed
using literature and experimental results of the
programme research.
3.2 Techno-economic modelling
The overall techno-economic modelling approach
used in the programme is illustrated in Figure 1.
To support R&D and to provide preliminary
techno-economic performance information for
industry regarding the processes and products
developed in the programme, various process
concepts were created, designed, and evaluated
in the screening phase. A method for this early-
stage concept screening was developed. The
method exploits early-stage process design
methods to obtain comparable results for the
different overall production systems that are
possible for a given concept. The method is
illustrated in Figure 2. Prices of all raw materials,
chemicals, utilities, and the different factors

used for fixed cost assessment were agreed,
and the concepts were created together with
the project partners. For capital cost estimation,
methods developed by Bridgewater and Zevnik
& Buchanan 1
were used.
In screening, concepts were developed from
R&D ideas by specifying targeted end products,
feedstocks, design capacities, process
integration opportunities and main process
parameters. Variable and fixed production
costs were calculated using parametric models
and input-output material and energy balances.
Based on the results of the screening and the
progress of the research, together with project
partners conceptual designs for five cases were
developed.Processmodellingwasthenconducted
for these designs: block-flow diagrams were
designed or further refined from those designed
in the screening phase, and mass and energy
balances were modelled using process simulation.
The simulation models were parameterized using
experimental research results, partners’ expertise
and literature. If pulp mill integration was part of
the concept, the interface between the processes
was defined and pulp mill impacts were simulated
using a steady-state process simulation model of
the entire system. A pulp mill model developed in
the EffFibre programme was used. The technical
analysis focused on the main process (production
and purification of the main product), and
1 e.g. Holland, F.A. & Wilkinson, J.K. Perry's Chemical Engineers'
Handbook, section 9 (Process Economics), McGraw-Hill, 1999
recycling of the reaction media and catalysts. If
enough data was not available, short-cut models
and assumptions were used. Preliminary variable
production costs were assessed for sensitivity
analysis purposes. The resulting process
descriptions and balances were further used in
quantitative economic analysis and qualitative
modelling of the cases.
Net Present Value (NPV) and Return on
Investment (ROI) were the main quantitative
feasibility analysis instruments used to evaluate
the economic feasibility of the cases. An
enhanced probability simulation tool was used
in the analysis to forecast the probabilities
of achieving positive outcomes for NPV and
ROI. This method was chosen because the
probability of a given outcome can often be more
informative than the actual figures themselves,
especially at the early development stage.
In the qualitative opportunity assessment
many variables were assessed. The variables
were divided into two categories: internal and
external. The variables were evaluated on a
scale from 2 (high) to low (0) opportunity. In
addition, different weight factors were given
to the variables, reflecting their relative
importance. External variables in the analysis
mainly included market-related factors such as
market size and growth. Economic feasibility
was also a key external variable. Internal
variables, in turn, mainly included technical
variables such as technical feasibility, product
quality feasibility and technical availability.
Figure 2. Light techno-economic analysis method developed for concept screening.

4. Results
4.1 Physico-chemical modelling of hot
water extraction
Chip and reactor scale modelling of PHWE
As an example reaction definition, Figure 3
shows the reaction scheme for xylan. The data
from the experimental treatments indicate that
there are two sub-components of xylan (XN1
and XN2
) with different reaction rate constants
for degradation into oligosaccharides (XOS).
The temperature dependency of the reaction
rates is assumed to follow the Arrhenius equation.
Table 1 shows the related pre-exponential
(frequency) factors and activation energies.
A similar reaction scheme was developed
for the degradation of glucan. In that
case, the monosaccharide degrades into
hydroxymethylfurfural (HMF). A Matlab program
and a Comsol multiphysics program, based
on estimated reaction rates and values for
physical parameters describing diffusion in the
wood particle and flow in the porous medium,
were constructed to simulate PHWE at chip
Figure 3. Reaction pathways for xylan in PHWE. Notation: XN1
– fast-degrading xylan, XN2
– slowly
degrading xylan, XOS – xylo-oligosaccharides, X – xylose, F – furfural, DP1,DP2 – unspecified low molecular
weight degradation products, ki – reaction rate constant.
k1 k2 k3 k4 k5
A (min-1
) 3.12 ∙ 1017
7.28 ∙ 1017
6.58 ∙ 1012
3.08 ∙ 1012
5.13 ∙ 1016
Ea
(kJ mol-1
) 161.04 179.54 127.94 129.91 168.52
Table 1. Pre-exponential factors (A) and activation energies (Ea
) for xylan reactions.
level and reactor level, respectively. The Matlab
program calculates the time development of
the 3D distribution over the wood chip of the
various reaction products of lignin, xylan and
glucan. It is possible to alter the size of the
chip, the cooking time and the temperature in
the simulation. Likewise, the Comsol program
simulates the product distributions in the
reactor. The geometry and heating circulation
of the simulated reactor can be changed, as can
the porosity and permeability of the chip bed.
The main results of the modelling of hot water
extraction were increased knowledge of the
phenomena taking place in the system, and the
simulation tool that can be used in further hot
water extraction research.
Comprehensive modelling of PHWE chemistry
The comprehensive PHWE chemistry modelling
work provides interesting insights into the phe-
nomena taking place during PHWE. A schematic
illustration of the various phenomena and reac-
tions included in the model is shown in Figure 4.
Considering the onset of the PHWE reactions,
the uronic acids seem to be responsible for

introducing hydrogen ions into the fibre-bound
liquid, which, when the temperature is raised,
begin catalysing various reactions such as
deacetylation and hemicellulose degradation.
Metal ions, naturally present in the fibre
wall, neutralize part of the acidity. In order to
accurately estimate the initial hydrogen ion
concentration in the fibre wall liquid, it is crucial
to know the amounts of all chemical compounds
influencing pH. According to our current
understanding, it seems that uronic acids and
metal ions are the most relevant compounds.
Although, based on our modelling results and
some evidence provided in the literature, the
fibre-bound liquid is acidic, the water external
to the wood particles is close to neutral pH.
The ion exchange, i.e. the unevenness of the
electrolyte composition, in these two liquid
phases (fibre-bound and external liquid phase)
was modelled using Donnan theory, which is
widely used and acknowledged in the context
of pulp bleaching and, for example, in studying
semipermeable membranes.
As hemicelluloses start to dissolve from the fi-
bre wall, the uronic acids also dissolve. Dissolv-
ing uronic acids weaken the ion exchange phe-
nomena, and metal ions are also able to move
to the external liquid phase as they are no long-
er held in the fibre-bound liquid as counter ions
for the dissociated uronic acids. Besides acetic
acid, uronic acids and metal ions seem to have
a significant influence on the evolution of pH in
the external liquid phase.
Understanding the behaviour of pH during hot
water extraction is essential because hydrogen
ions catalyse cleavage of the glycosidic bonds,
thus shortening the hemicellulose polymers.
Besides predicting the evolution of pH, another
novelty of the model is its capability to predict
the evolution of the hemicelluloses’ molecular
weight distribution during hot water extraction.
Furthermore, monomer and other oligomer
concentrations are also reproduced. This
feature facilitates the optimization of hot water
extraction performance with respect to various
end products. The amounts of dissolved lignin
and furfural, which are potentially problematic
for the process, are also predicted by the model.
Figure 4. Schematic of the phenomena included in the comprehensive hot water extraction model.

The chemistry model for PHWE can be
used together with the chip and continuous
digester models developed in the EffFibre/VIC
project. Furthermore, a flow-through reactor
model using a simplified chemistry model
was also developed. In the chemistry model,
only the cleavage of the glycosidic bonds in
hemicelluloses was considered. The chemistry
model also reproduces the molecular weight
distributions of the extracted hemicelluloses.
The developed model enables a priori simulations
of the effect of different buffers and additives on
pH evolution. Thus, screening work concerning
optimal conditions, such as particle size,
additives, liquid-to-wood ratio, temperature and
duration, can be done with the simulation model.
From the academic point-of-view, this kind of
phenomena-based modelling enables testing
of different theories in a quantitative manner
and reveals shortcomings in the present
theories. For industry, the model can be used in
process optimization and development.
4.2 Early-stage techno-economic modelling
of concepts based on research ideas
Over 100 ideas were evaluated using the method
illustrated in Figure 2 (see Table 2 for aspects
varied and combined). The concepts and overall
systems were defined based on discussions
with researchers and industry representatives.
Based on the early-stage techno-economic
modelling of all of the process and overall system
ideas, the most promising future biorefinery
concepts were selected by the industrial
partners for further detailed modelling.
4.3 Quantitative and qualitative
modelling of selected Future Biorefinery
concepts
Five promising overall production systems based
on the programme’s technology development
ideas were identified and evaluated:
1) Hot water extraction of high molecular
Research topic Examples of concepts
Pressurized hot water
extraction (PHWE)
PHWE at a sawmill, kraft pulp mill, TMP plant, or CTMP/soda plant.
Extraction of high or low molecular weight hemicelluloses.
Extraction of sawdust or chips.
Ionic liquids Kraft pulp to acetate-grade dissolving pulp.
Wood to TMP-like pulp.
Wood to kraft-like pulp.
Composites Internally, externally or unmodified (using internal plasticization, chemi-
cals, enzymes).
Different lignin-fibre-plasticizer ratios.
Barriers PHWE-xylan, modification of GGM, TOFA hybrid polymers, fatty acid cellu-
lose esters, reactive milling, cellulose-polymer blends.
Hydroxy acids (HA) HA separation technologies (separate & combined): a) Electrodialysis, b)
Ion-exchange, c) Chromatography, d) Acidification, e) Cooling crystalliza-
tion.
Products: a) Hot glues, b) Chelating agents.
Future biorefineries Combinations of the above-listed concepts integrated into the forest in-
dustry supply chain.
Table 2. Evaluated concepts from FuBio JR2 process and product development.

weight (MW) hemicellulose from sawdust, 2)
Separation of hydroxy acids from kraft black
liquor, 3) Biocomposites, 4) Biobarriers, and 5)
Future sawdust biorefinery based on hot water
extraction.
Case 1 – Hot water extraction of high MW
hemicellulose from sawdust
Figure 5 illustrates the process concept and
the main process parameters and balances for
extractinghighmolecularweighthemicelluloses
from spruce sawdust. The production scale was
defined based on sawdust availability in Finnish
sawmills. The process conditions (temperature,
pressure, solid:liquid ratio, flux) and efficiencies
(extraction yield, separation and purification
efficiencies) were based on experimental
results. The balances were simulated using the
Balas® process simulator.
Two scenarios were evaluated, in which the
extraction yield and extract dry content were
varied (Table 3).
The mass and energy balances and the
preliminary dimensioning data for the equipment
were used in quantitative economic analysis, in
which it was clearly seen that the production
costs for the material were high, more than
double the price of competing materials. One
major reason for the high costs is the small
design capacity which results in high fixed costs
(e.g. personnel and capital costs)
The process is considered to be relatively mature
(suitable process equipment exists); however, the
overall concept would require further refinement.
For example, the yield based on the experimental
work of the programme at the time of conducting
thestudywasverylow.Moreover,theendproduct
(extract) is not pure high-MW hemicellulose and
might not be suitable for high-value applications
without further processing.
Base case Optimistic case Unit
Raw extract yield (= dissolved sawdust
fraction led to membrane)
2 10 % on dry
sawdust
Dry content of extract 1.1 5.0 %
Table 3. Scenario definition for high MW hemicellulose extraction.
Figure 5. Block-flow diagram of Case 1: High MW hemicellulose extraction from sawdust.

Case 2 – Separation of hydroxy acids from
kraft black liquor
From the 12 alternative hydroxy acid separation
process concepts and overall systems
(alternatives listed in Table 2), two were chosen
by the industrial partners for detailed analysis.
In these two overall systems, the product
would be either a mixture of all hydroxy acids,
or two mixtures, a high and a low molecular
weight mixture targeted at hot glue or hot glue
and chelating agent applications, respectively.
The process concept included two alternatives,
which utilized different technology for liberation
of acids from their salt form: ion exchange (IEX)
or electrodialysis (ED). The process concept is
illustrated in Figure 6.
The main assumptions for the case evaluation
were:
• Pulp mill production capacity 700 000 adt/a
• Hydroxy acids production rate
- 1/3rd of pulp mill black liquor processed
and 15% yield of HA -> production 35 000t/a
- Volatile (formic and acetic) acids yield 7%
of pulping raw material
• H2
S handling and volatile acids recovery
excluded
• Pulp mill integration
- Evaluated using WinGems pulp mill model
developed in the EffFibre programme
- Cooking variables (effective alkali and
sulfidity) kept constant by NaOH makeup
and fly ash purge
The results of modelling the four scenarios
were used in quantitative and qualitative
evaluation of the case. The economics seem
highly promising if acids production is targeted
exclusively at glue production, compared to the
option of using part of the acids production as
chelating agent. However, although the product
price is quite low, the product quality currently
remains somewhat uncertain.
As process technologies, all of the considered
process steps are mature in different contexts.
However, processing of kraft black liquor using
these separation technologies (chromato-
graphicseparation,ionexchange,electrodialysis)
has been done only at laboratory scale and
therefore further technology development is
needed. Furthermore, impacts on the pulp mill
chemical recovery cycle (Na/S balance) should
be minimized and products’ applicability further
evaluated. Thus, the overall concept still needs
development.
Case 3 – Biocomposites
A total of 26 overall biocomposite production
systems were analysed using light techno-
economic analysis. Of these, two were selected
for more detailed evaluation: lignin-fibre
composite without (Figure 7 a) and with internal
lignin plasticization (Figure 7 b).
The recipes were based on experimental results
and optimization for targeted end product
properties (composite mechanical properties):
Figure 6. Block-flow diagram of Case 2: Hydroxy acids separation from kraft black liquor.

lignin content 36% and 41%, and fibre
content 30% and 20% for the two concepts
respectively; the remainder of the composite
pellet was plasticizer. Internal plasticization
was assumed to be done using purchased
acetic acid anhydride, and the excess acetic
acid that is recovered after plasticization was
assumed to be sold.
Process equipment for the composite
production exists, and the composite properties
can be further developed/targeted and the
most suitable applications found to develop the
overall concept.
The process without internal plasticization is
simpler and showed better feasibility, but as the
composite price range used in the analysis is
wide, product quality will ultimately determine
the price. Therefore, if internal plasticization
enhances the properties, the economics can
absorb the cost of internal plasticization. Acetic
acid as a side-product also has a significant
impact on the overall feasibility.
Case 4 – Biobarriers
Two alternative concepts were also selected
for detailed analysis of biobarrier production
based on light techno-economic analysis
and technology development. The two very
different concepts considered were the
production of hydroxypropylated xylan based
and cellulose co-polymer based barriers in
fast-food packaging. The process block flow
diagrams are illustrated in Figure 8.
In the hydroxypropylated xylan (HPX) case,
xylan extraction from kraft pulp is included in
the concept to enable efficient alkali recycling.
Separation and purification process parameters
were based on literature and partner input.
The cellulose co-polymer case was based on
the research partner’s definition and literature
process parameters.
The cellulose co-polymer product consists
mainly of inorganic compounds (sodium and
zinc) and its suitability for food packaging
Figure 7. Block-flow diagram of Case 3: Composite concepts: a) no modification of raw materials, b)
internal plasticization of lignin.
a)
b)

Figure 8. Block-flow diagram of Case 4: Barrier concepts: a) hydroxypropylated xylan, b) cellulose polymer
blend.
a)
b)
applications thus needs careful examination. On
the other hand, in the hydroxypropylated xylan
case the impacts on kraft pulp properties should
be evaluated and possible further valorisation
of the pulp after xylan extraction to dissolving
pulp considered instead of selling it as kraft pulp.
Therefore, in both cases, further technology and
concept development is needed.
As the economic feasibility of both cases is
dependent on coating layer costs, cost per
area is more critical than cost per tonne. Figure
9 shows how the probability of a positive ROI
changes as a function of layer cost (c/m2
) with
different layer amounts.
Case 5 – Future sawdust biorefinery based on
hot water extraction
The fifth case was constructed around several
project focus areas:
• Hot water extraction of hemicelluloses from
sawdust to produce high and lower MW
fractions; use of the high MW fraction for
barrier production.
• Kraft cooking of the extraction residue to
obtain black liquor and pulp; separation
of lignin from the black liquor, e.g., for
composite production; use of the pulp as
fibre for composites, or oxygen delignified
and bleached as pulp.

The concept is illustrated in Figure 10.
The main assumptions of the case were:
• 100 000 or 20 000bdt/a sawdust
• Process integrated into a kraft pulp mill
(600 000 t/a)
• Washed pulp to oxygen delignification stage
of the kraft pulp mill
The concept was modelled using the Balas®
process simulator and the integration impacts
were simulated using the WinGems pulp mill
model developed in the EffFibre programme.
The main integration impacts for 20 000bdt
sawdust/a capacity would be:
• Pulp from sawdust cooking increases pulp
production by 1.5%
Figure 9. Probability of a positive ROI in the studied barrier cases with different coating amounts as a
function of coating layer material costs (cent/m2
). Cepe: cellulose co-polymer; HPX: hydroxypropylated
xylan. Reference material cost illustrated on x-axis: PE&PP – polyethylene & polypropylene, PET –
polyethylene terephthalate, PA – polyamide.
Figure 10. Block-flow diagram of Case 5: FuBio concept with hypothetical production capacity.

Figure 11. Operating cost breakdown of the analysed cases
• 1.5% higher fibre line capacity required
downstream from oxygen delignification
• 1.4% increased white liquor demand
• 2.2% increased evaporation requirement at
evaporation plant
• Decreased net electricity production
• Increased fly ash purge
Four products are generated: two streams of
extracted hemicellulose, sawdust-based pulp,
and lignin separated from the black liquor. The
raw material for the process is sawdust. In
this case, the sawdust cost is essential to the
economic feasibility of the case.
The overall system requires further development
and, due to its small design capacity, process
simplifications may be needed, e.g., related
to lignin separation. The clearly improved
extraction yields and better selectivity in
purification compared to Case 1 obtained at the
laboratory scale indicate good potential, but the
final use of the other fractions requires further
development.
Summary
The cost breakdown of the evaluated cases
varies somewhat, as illustrated in Figure 11.
The difference in cost distribution results partly
from the selected modelling scope (e.g. whether
the feedstock has a purchase cost or not), the
scale of production, and the processing type
(e.g. whether chemicals are needed or not).
These results should not be used to compare
economic feasibility between cases, as they
only indicate the relative cost distribution.
A preliminary cross-case comparison can,
however, be made between cases 1 and 5 where
PHWE was considered to be one of the main
technologies: with higher hemicellulose yield
the share of fixed costs decreases (feedstock
flow nearly the same in these cases) while, on
the other hand, the added lignin separation
process requires chemicals.

Figure 12 shows the qualitative analysis results
based on the present economic evaluation
and assessment of other qualitative analysis
variables. Based on their total scores, the
studied cases were plotted (x-axis: sum of
internal variables; y-axis: sum of external
variables) with the level of opportunity
increasing from left to right (x-axis) and
upwards (y-axis).
Comparing the cases, the level of opportunity
was found to be highest in external (market-
related) terms for the separation of hydroxy
acids from black liquor and for lignin
composites. In these two cases, technical
challenges related to operation and product
quality were, however, found. Technically, the
most promising cases were found to be two
cases based on hemicellulose fractionation:
barrier films based on extraction of xylan from
bleached pulp, and hot water extraction of
hemicelluloses from sawdust and subsequent
sawdust cooking. However, these cases scored
relatively low in market-related terms.
Conclusions, risks and suggestions for each of
the five cases are listed in Table 4.
5. Exploitation and impact of
results
The modelling methods and tools and
knowledge developed focusing on hot water
extraction phenomena, purification of the hot
water extract, and the sustainability of the
different process concepts and value chains
provides crucial new information for industry
decision making and for steering future
research.
The thorough modelling of PHWE was based
on combined knowledge of aqueous phase
thermodynamics, ion exchange, reaction
kinetics, and mass transfer. The resulting
model can be used in optimization of PHWE
conditions to produce either sugars or high
molecular weight hemicelluloses, and for
Figure 12. Qualitative opportunity assessment of the studied Fubio JR2 cases.
Fubio Opportunity Evaluation
High
High
Case 1 – Hot water extraction of high MW hemicellulose from sawdust
Case 2 – Separation of hydroxy acids from Kraft black liqour
Case 3 – Biocomposites
Case 4 – Biobarriers
Case 5 – Future sawdust biorefinery based on hot water extraction
External
Internal
Low
Low

Case Conclusion Highest risks Suggestions
1 • New concept that could generate
additional revenue for a sawmill.
• Very small production rates and poor
economic potential.
• Technical and economic feasibility
(ROI negative in all cases; labour and
capital costs significant).
• Target concepts where the cellulose/
lignin fraction has an end-use of
higher added value (compared to
energy use) and hot water extraction
is needed to achieve this.
• Step-wise extraction with multiple
end products could be another
interesting concept (poly-, oligo- and
mono-based).
2 • Target product markets are expected
to grow annually 4-6%
• Electrodialysis-based production
concept could have >10% IRR with a
product value of 1000 €/bdt.
• Both production routes and product
alternatives seem to have positive as
well as negative environmental and
social impacts based on preliminary
analyses.
• Technical feasibility – experimental
work has been carried out with
soda black liquor, the separation
processes have not been piloted
using black liquor long enough to get
data, e.g., on fouling & cleaning.
• Product quality – application
testing has not been carried out
using obtained acid mixtures as
feedstocks.
• Look for alternative ion-exchange
system cleaning (organic acid based,
or circulation based) to replace the
high H2SO4 demand (and to remove
high cost of chemicals and fly ash
disposal).
• Conduct further product testing (hot
melt and chelating agent).
3 • Target market is ~2Mt/a with
expected growth of over 5% CAGR;
prices are high on average.
• Unmodified lignin case seems to
have very good economic return
and internal plasticization case
has potential assuming the quality
improvement obtained from
plasticization is worth over 500 €/t.
• Product quality – strength properties
of both composite types should be
tested in the application to verify
their performance.
• Technical aspect – relatively large
share of the product is plasticizer,
which is potentially produced from
food-grade feedstock.
• Conduct further product testing in
target application.
• Investigate other possible
plasticizers and/or the possibility to
decrease its share in the composite.
4 • The target market is ~ 1Mt/a (Global)
and 0.4Mt/a (Europe), considering
large fast-food chains. Annual volume
growth expected to be about 5%.
• Cellulose co-polymer case seems to
have good economic return due to
very good properties with thin layer
and relatively simple process.
• Hydroxypropylated xylan case
requires thinner layer thickness with
same properties to become more
attractive.
• Product quality – Cellulose co-
polymer product consists mainly
of inorganic compounds (sodium
and zinc) and the suitability in food
packaging application needs careful
inspection.
• Technical aspect – in
hydroxypropylated xylan case the
xylan extraction system integration
impacts on pulp mill process and
cellulose product quality.
• Study the compatibility of the barrier
in combinations of different barrier
materials (oxygen, water vapour
barriers).
• In hydroxypropylated xylan case,
integrated concept with added
value cellulose product should be
considered.
5 • Combined system shows promising
economic performance compared to
Case 1 because of improved yield and
integration into pulp mill.
• Lignin separation system is very
small compared to e.g. announced
Lignoboost projects and requires
significant investment.
• Many products and technologies
may be challenging.
• Sawdust has other competing uses.
• Compatibility of the hot water
extraction based high molecular
weight hemicelluloses for barrier
application.
• Further analysis of the compatibility
of the products in the end
applications (barriers, animal feed,
lignin in composite).
• Evaluate which product combination
generates most value from the
feedstock.
Table 4. Summary of case evaluations.

obtaining information that could be difficult to
measure experimentally. The new models were
implemented on a digester modelling platform,
which can be used for simulation of industrial-
scale continuous hot water extraction units.
Simulation of a hot water extraction and
alkaline pulping sequence for the production
of dissolving pulp could be one possible case
study. Furthermore, the models for hot water
extraction phenomena (incl. xylan degradation
kinetics, chain scission and diffusion in a chip,
and digester flow) can supplement concept
modelling of processes using hot water
extraction.
The light techno-economic analysis revealed
the potential of the technologies developed
in FuBio JR2. For example, the potential of
integrating the PHWE system into different
host processes, the preliminary economic
performance of new hydroxy acids separation
Table 5. Partner organizations and their research roles.
techniques compared to more mature
technologies, or the costs of modifying the
lignin for biocomposite production. The results
of the sustainability analysis on the other
hand highlighted the opportunities offered
by the selected concepts to different players
in the value chain. This new information
on business potential can be exploited by
companies using the concept and companies
developing enabling technologies for the value
chain. Moreover, the refined overall techno-
economic analysis approach can be utilized for
evaluating other new technologies than those
developed in FuBioJR2.
6. Networking
A summary of the partners and their
contributions in this context is presented in
Table 5.
Work package partners Role of the participating organization
Aalto University Physico-chemical modelling of hot water extraction and
implementation of the model into a process simulator, kinetic
modelling of hot water extraction at chip and reactor level
Andritz Work Package Coordinator
GloCell Quantitative analysis in the techno-economic modelling, market
entry evaluation method development
Kemira Industrial tutor
Lappeenranta University of Technology Multivariate analysis
Metsä Fibre Industrial tutor
Pöyry Management Consulting Techno-economic assessment through investment and
production costs and qualitative opportunity assessments
Stora Enso Industrial tutor
University of Oulu Social impact assessment
UPM-Kymmene Industrial tutor
Valmet Industrial tutor
VTT WP leader. Early-stage techno-economic modelling and method
development, new biorefinery process integration method
development, process concept design and process modelling,
life cycle assessment

7. Publications and reports
Abdulwahab, M. Modelling of ionic liquids' ther-
mal separation and recycling in biomass frac-
tionation, M.Sc. Thesis, Aalto University, 2013.
Borrega, M., Nieminen K. and Sixta, H. Deg-
radation kinetics of the main carbohydrates
in birch wood during hot water extraction in a
batch reactor at elevated temperatures, Biore-
source Technology, 102, 2011, 10724-10732.
Hytönen, E. and Leppävuori, J. Future Biore-
finery (FuBio) research into process concepts –
early stage process evaluation and screening,
Nordic Wood Biorefinery Conference NWBC
2014, Stockholm, Sweden, March 25-17, 2014.
Kleen, M. Statistical modelling of pressurized
hot water flow-through extraction process, VTT
Research Report, VTT-R-2688-14, May 2014.
Kleen, M. Statistical modelling of pressurized
hot water batch extraction process, VTT Re-
search Report, VTT-R-2637-14, May 2014.
Kleen, M., Pranovich, A. and Willför, S. Statis-
tical modeling of pressurized hot water extrac-
tion process to produce hemicellulose with de-
sired properties, 4th International Conference
on Biorefinery—towards Bioenergy (ICBB2013),
Xiamen, China, December 3-5, 2013.
Kuitunen, S. Phase and reaction equilib-
ria in the modelling of hot water extrac-
tion, pulping and bleaching (http://urn.fi/
URN:ISBN:978-952-60-5618-0), Doctoral dis-
sertation, Aalto University, 2014.
Kuitunen, S., Vuorinen, T. and Alopaeus, V.
The role of Donnan effect in kraft liquor impreg-
nation and hot water extraction of wood, Holz-
forschung, 67, 2013, 511-521.
Liu, Z., Ahmad, W., Kuitunen, S. and Alopaeus,
V. Modeling of mass transfer and degradation
of hemicelluloses in flow-through hot water ex-
traction, Submitted to Industrial & Engineering
Chemistry Research.
Liu, Z., Suntio, V., Kuitunen, S., Roininen, J.
and Alopaeus, V. Modeling of mass transfer
and reactions in anisotropic biomass particles
with reduced computational load, Industrial
& Engineering Chemistry Research, 53, 2014,
4096 - 4103.
Visuri, J., Song, T., Kuitunen, S., and Alopaeus,
V. Model for Degradation of Galactoglucoman-
nan in Hot Water Extraction Conditions, Indus-
trial & Engineering Chemistry Research, 51,
2012, 10338-10344.

NEW SOLUTIONS
FOR BIOMASS
FRACTIONATION
BY PRESSURIZED HOT WATER
EXTRACTION, SUPERCRITICAL
WATER TREATMENT AND
DELIGNIFICATION
CONTACT PERSON – Work Package 1 leader Risto Korpinen, risto.korpinen@abo.fi
Aalto University: Fanny Bardot, Marc Borrega, Herbert Sixta, Lasse Tolonen, Yuying Zhang.
Andritz: Christian Järnefelt, Tiina Rauhala
Finnish Forest Research Institute: Olli Byman, Sanna Hautala, Hannu Ilvesniemi, Petri Kilpeläinen,
Veikko Kitunen, Kaisu Leppänen, Zhiqiang Li, Johanna Tanner, Teemu Tikkanen
Kemira: Marcus Lillandt, Anna-Maija Saariaho
Lappeenranta University of Technology: Mohammed Al-Manasrah, Mari Kallioinen, Elsi Koivula,
Mika Mänttäri, Minna Nevalainen, Tuomas Nevalainen, Liis Retsja
Metsä Fibre: Ismo Reilama
Stora Enso: Kalle Ekman
University of Helsinki: Maija Tenkanen
University of Jyväskylä: Raimo Álen, Jarkko Kuivanen, Joni Lehto, Mika Leppäaho
UPM-Kymmene: Ulf Hotanen, Mika Hyrylä
VTT Technical Research Centre of Finland: Anne Kallioinen, Marjatta Kleen, Hanna Kyllönen, Tiina Liitiä,
Marjo Määttänen, Tarja Tamminen
Åbo Akademi University: Ricardo Garcia de Castro Insua, Henrik Grénman, Jarl Hemming, Jens Krogell,
Zhiqiang Li, Andrey Pranovich, Jan-Erik Raitanen, Jussi Rissanen, Tapio Salmi, Annika Smeds,
Maunu Toivari, Stefan Willför, Chunlin Xu

ABSTRACT
Pressurized hot water extraction (PHWE) and subsequent delignification processes
were examined for their ability to separate hemicelluloses, lignin and cellulose from
wood biomass. In addition, the separation and purification of PHWE extracts and high-
temperature hydrothermal treatment of microcrystalline cellulose were also studied.
PHW extraction parameters were successfully tailored to enable the extraction of relatively
large amounts of hemicellulose of relatively high molar mass from wood. If molar mass is
not considered a critical factor, nearly all hemicelluloses – constituting approximately up
to one third of wood biomass – were extractable. Additionally, the pH of the PHWE process
was monitored and adjusted as desired by the addition of dilute alkali.
The hemicellulose-rich extracts obtained by PHWE contain mixtures of hemicelluloses of
varying chain length. A variety of impurities, such as wood extractives and lignin-derived
compounds, are also present. In addition, the dry solids content of the extracts is usually
relatively low. It was possible to concentrate, purify and fractionate the extracts according
to molecular size by combining appropriate pre- and/or post-treatments with membrane
filtration, while maintaining sufficient filtration capacity.
Crystalline cellulose residues were successfully hydrolyzed and dissolved by rapid near-
and supercritical water treatments to produce narrowly distributed, low-molar-mass
celluloses and cello-oligosaccharides.
The fibrous fraction after PHWE was further isolated as a cellulose-rich fraction by sulfur-
free delignification processes. Hardwoods defibrated more readily than softwoods due to
differences in lignin structure. The cellulose-rich fraction can be further processed into
various products, such as regenerated cellulose.
Keywords:
analytical methods, cellulose, delignification, hemicelluloses, lignin, pressurized hot water extraction,
pulp, purification, separation, super critical water, wood biomass

1. Background
The structural building blocks of wood –
hemicelluloses, lignin and cellulose – account
for the vast majority of all woody biomass.
Pressurized hot water extraction (PHWE) offers
an environmentally sound water-based means
of separating out these valuable components.
The extracted hemicellulose and lignin fractions
offer a source of valuable biochemicals and
other bioproducts, thus contributing to reduced
reliance on petrochemicals, while the cellulose-
rich fibre fraction can be used in composites or
further processed into new fibre products or
regenerated cellulose.
In the PHWE process, wood is treated with
water at elevated pressure and temperature,
up to 220 °C, to separate the hemicellulose-
rich fraction from the wood matrix. No organic
solvents or toxic chemicals are needed. The
attained fibre fraction subsequent to PHWE is
further fractionated into lignin and cellulose
by sulfur-free delignification processes and
possible additives.
Pressurized hot water treatment in near- and
supercritical conditions, in which distinct
liquid and gas phases are absent, can be used
to achieve rapid hydrolysis and dissolution
of crystalline cellulose residue to produce
low molar mass polymer without addition of
cellulose solvent.
Isolation of hemicellulose, lignin and cellulose
from each other by PHWE is, however, not
complete and the obtained fractions thus
contain a variety of impurities. In addition,
the fractionation processes are relatively
water intensive. Therefore, purification and
dewatering processes are needed to enable
utilization of these fractions in various
applications.
2. Objectives
I) Investigation of the use of pressurized hot
water extraction and supercritical water
treatment for the fractionation of wood. II)
Concentration and purification of the obtained
hemicellulose- and lignin-containing fractions
to enable their utilization in various applications.
III) Further delignification of the extracted
residues to produce novel pulps. IV) Transfer
of knowledge obtained from laboratory scale
experiments to the pilot scale.
3. Research approach
Spruce and birch wood were pressurized hot
water extracted using different reactor setups
(batch, flow-through and cascade). The reactor
volumes varied from 33 ml to 300 l. An example
of a batch mode setup, accelerated solvent
extraction (ASE) system, used in the PHWE
experiments can be seen in Figure 1. Different
extraction parameters were studied, such as
temperature, pressure, time and particle size.
The aim of the extractions was to produce as
high-molar-mass hemicelluloses as possible
at high yield. The extracted residues were
delignified using sulfur-free processes. The
aim was to produce pulps suitable for the
production of regenerated cellulose and other
products. The hemicellulose-rich extracts were
fractionated, concentrated and purified using
membrane filtration and different purification
techniques. Crystalline cellulose residues
were hydrolyzed and dissolved by rapid near-
and supercritical water treatments in order to
produce narrowly distributed, low molecular
weight celluloses and cello-oligosaccharides at
high purity. Analytical methods needed in the
wood fractionation processes were mapped
and method comparisons were carried out.

4. Results
4.1 Key results of PHWE
Particle size and temperature had a significant
effect on the extraction of hemicelluloses, as
illustrated in Figures 2 and 3. Norway spruce
sapwood of different particle sizes (0.25–1.0
mm vs. 8–12 mm) was pressurized hot water
extracted using different extraction times
and temperatures. The smaller particle sizes
resulted in a considerably higher amount of total
dissolved solids in the extracts. Furthermore,
higher extraction temperature resulted in
higher hemicellulose yield, but the average
molar mass of the hemicelluloses decreased. AtFigure 1. Accelerated solvent extractor ASE 350.
Figure 2. Amount of dissolved wood substances in extract as a function of extraction temperature and time,
a) sawdust and b) blocks.
a) b)
Figure 3. Average molar mass of ethanol precipitated hemicelluloses from extracts as a function of
extraction temperature and time, a) sawdust and b) blocks.
a) b)

higher temperature and prolonged extraction
time, more intense hydrolytic degradation
of carbohydrates and lignin takes place.
Additionally, larger wood particles cause mass
transfer limitations, preventing molecules from
migrating out from the wood matrix.

Monitoring and controlling pH is essential.
If the pH drops too low during extraction the
hemicellulose chains start to degrade and
lower molar mass is obtained. The pH values of
the extracts were typically measured at room
temperature after removing the samples from
the reactor. This resulted in a delay in the data.
To avoid this, high-temperature pH electrodes
were installed and tested. As Figure 4 shows,
the pH measured inside the reactor during
PHWE was approximately 0.5 units higher
than that measured at room temperature. A
difference of 0.5 pH units corresponds to a 3.2
times lower H+
concentration. It can also be
seen that by adding dilute alkali and using high-
temperature pH electrodes it was possible to
adjust and maintain the pH at the desired level.
4.2 Up-scaling experiences of PHWE
Two pilot scale PHWE appliances were used to
demonstrate the extraction results obtained
from laboratory experiments. Figure 5 shows
the 300-litre reactor (flow-through mode)
and the 30-litre reactor (both batch and flow-
through modes). Due to the large size of
these reactors compared to laboratory scale
reactors, they were also used to produce
sufficient amounts of extracts and PHWE-
treated fibres for further processing.
It was shown that the laboratory scale
extractions could be up-scaled by a factor of
300 and 6000. The results of birch wood flow-
through pressurized hot water extraction at the
laboratory scale and pilot scale using the same
extraction conditions and reactor dimensions
are shown in Table 1.
The amounts and extraction rates of
hemicelluloses extracted from birch wood were
similar for both the laboratory and pilot scale,
as shown in Figure 6. In addition, the pH profile
of the extracts was identical.
Figure 4. In-line pH control during PHWE at 170 °C.

Based on the modelling work done in the
laboratory using a 100 ml reactor, pilot scale
extractions of spruce wood were carried out
using a 30-litre reactor (scale-up factor 300)
in batch mode. The obtained model values and
the pilot scale results were comparable (Table 2)
although the pilot- and laboratory scale PHWE
setups had slightly different configurations.
Figure 5. Pilot scale PHWE reactors, 300 l flow-through (a) and 30 l batch and flow-through (b).
a) b)
Laboratory scale (0.05 l) Pilot scale (300 l)
Temperature 160 °C 160 °C
Diameter / length, ratio 34 mm / 59 mm, 0.6 590 mm / 1040 mm, 0.6
Flow rate 3.3 ml/min 20 l/min
Residence time 12 min 12 min
Extraction time 60 min 60 min
Table 1. Laboratory- and pilot scale extraction conditions.
Figure 6. a) pH of the extracts, b) hemicellulose yield and average molar mass, c) cumulative yield of
hemicellulose, d) chemical composition of extracts after 60 min extraction. Error bars represent the
relative standard deviations of three parallel extractions.
d)a) b) c)

Spruce extractions using batch mode and
30-litre reactor were performed either at 160
°C for 40 min or at 170 °C for 60 min, both
with a water-to-wood (W:W) ratio of 5 or 10.
After PHWE and removal of the extract, the
extracted residue was washed at 50 °C for 30
min using the same W:W as in the extraction.
The amount of dissolved material was doubled
by using a W:W ratio of 10 instead of 5 in the
milder extraction conditions, as seen in Figure
7. In the harsher conditions, about 70% more
TDS was obtained when using a W:W ratio of
10. Slightly lower molar mass hemicellulose was
obtained when a higher W:W ratio was used.
The amount of dissolved material in the extract
could be further increased by compressing the
wood material after the extraction and washing
stages, as seen in Figure 8. The dissolved material
in the extract was 63 mg/g after PHWE and 118
mg/g after PHWE, washing and compression,
representingan87%increaseinTDS.Furthermore,
the molar masses of the different washing and
compression fractions were maintained.
The pilot scale PHWE experiments showed that it
was possible to obtain relatively high-molar-mass
hemicelluloses at relatively high yield by using:
• Moderate extraction temperature range
(155–165 °C)
• Relatively short extraction time (25–35 min)
• High packing degree of wood in the reactor
• Moderate water-to-wood ratio (5–10:1)
• Washing and compression of the wood after
extraction
• Secondary wall exposed wood by means of
mechanical treatment

Model values
(100 ml)
155 °C, 25 min,
W:W 5
Pilot results
(30 l)
155 °C, 25 min,
W:W 5
Model values
(100 ml)
170 °C, 20 min,
W:W 10
Pilot results
(30 l)
170 °C, 20 min,
W:W 10
pH of extract 4.2 3.9 3.7 3.6
Extraction residue yield,
% of orig.
94.7 93.2 86.1 82.8
Total dissolved solids
(TDS), mg/g wood
67.0 56.5 138.0 161.4
Average Mw, Da 17800 13936 9600 8346
GGM content of extract,
mg/g wood
23.8 27.2 67.2 90.5
Table 2. Comparison of values from a statistical model based on laboratory- and pilot scale results.
Figure 7. Total dissolved solids (a) and average molar mass (b) of PHW extracts and wash water from
spruce wood.
a) b)

4.3 Near- and supercritical water treatment
Near- and supercritical water treatment rapidly
hydrolyzed and dissolved the recalcitrant
crystalline cellulose and produced a mixture of
cellulose polymers of varying molar mass. The
used reactor setup can be seen in Figure 9.
After the treatment, the dissolved products
slowlyprecipitatedaslowmolarmassandhighly
crystalline cellulose with a narrow molar mass
distribution. The rest of the dissolved material
remained in solution as oligo- and monosugars
and a mixture of various degradation
products formed via concomitantly occurring
dehydration and retro-aldol reactions. The
shares of the reaction products depended on
the treatment time and temperature for the
two different microcrystalline celluloses, as
seen in Figure 10.
Dissolution as a precipitating polymer was
promoted by increasing the temperature, in
particular to above 320 °C, providing that the
treatment time was kept sufficiently short
to prevent extensive depolymerization of
the dissolved products. It was observed that
wood-derived microcrystalline celluloses
(MCCs) exhibited a higher velocity of
dissolution than those derived from cotton,
possibly due to the dimensional differences
of the cellulose crystallites.
Figure 8. Total dissolved solids (a) and average molar mass (b) of PHW extract, wash water and compression
water from spruce wood.
Figure 9. “MIKKI” reactor system for near- and supercritical water treatment of microcrystalline cellulose
using short reaction times below one second (a). The short treatment time is achieved by rapid heating
with preheated supercritical water and quenching with cold water (b).
a) b)
a) b)

Supercritical water treatment has potential
for cello-oligosaccharide production with
the advantage that cellulose dissolution and
hydrolysiscanbecarriedoutinasinglestage.Other
techniquesrequiretheuseofacellulosesolventto
dissolve cellulose crystallites and heterogeneous
hydrolysis, e.g. by acid hydrolysis processes,
mainly produces only monosaccharides. Cello-
oligosaccharide production was demonstrated
by treating commercially available MCC powder
in supercritical water at 380 °C for reaction
times of 0.2, 0.4 and 0.6 s (Table 3 and Figure
11). Up to 42% yield of cello-oligosaccharides
was reached with the 0.4 s treatment.
4.4 Delignification of PHWE-treated fibres
Pressurized hot water extractions of birch wood
chips at temperatures between 180 °C and 220
°C were conducted to extract hemicelluloses
and part of the lignin prior to pulping. The
intensity of PHWE was described by a modified
P-factor (here Log Pxs
). Soda-AQ pulping
experiments were then conducted at 150 °C,
with 22% NaOH and 1% AQ, based on initial
dry wood. The yield of main wood components
from birch wood after hot water extraction and
soda-AQ pulping are shown in Figure 12.
The cellulose content of the pulp remained
unaffected up to a hot water extraction
intensity (Log Pxs
) of about 4.5 (Figure 12 b),
but higher intensities led to extensive cleavage
of glycosidic bonds, thus facilitating the
occurrence of peeling reactions and resulting
in a cellulosic pulp with low yield. Nonetheless,
unbleached pulps with an acceptable yield (over
30% based on initial dry wood), and containing
over 90% cellulose, less than 5% xylan, and
about 2–3% lignin, were produced.
Treatment time
(s)
Residue
(%)
Precipitate
(%)
DP2–9 Cello-
oligosaccharides
(%)
Monosaccharides
(%)
0.2 8 35 29 3.0
0.4 0 11 42 6.1
0.6 0 < 1 30 9.1
Table 3. Yield of undissolved residue, precipitate, cello-oligosaccharides and monosaccharides after a
supercritical water treatment at 380 °C and 250 bar for 0.2–0.6 s.
Figure 10. Mass balances of two microcrystalline celluloses prepared by acid hydrolysis from prehydrolysis
kraft pulp (a) and cotton linter (b). Microcrystalline celluloses were treated in sub- and supercritical water
with varying temperature. Treatment time 0.20 s and pressure 250 bar.
0 %
20 %
40 %
60 %
80 %
100 %
250
260
270
280
290
300
310
320
330
340
350
360
370
380
Temperature (°C)
0 %
20 %
40 %
60 %
80 %
100 %
250
260
270
280
290
300
310
320
330
340
350
360
370
380
Temperature (°C)
Other
Water-soluble sugars
Precipitate
Residue MCC
from
prehydrolysis
Kraft pulp
MCC
from
Cotton
linter
a) b)

Selected wood residues after the pressurized
hot water extractions were subjected to
SAQ pulping (0.1% AQ) with the addition of
carbohydrate stabilization agents sodium
borohydride (BH) and anthraquinone-2-sulfonic
acid sodium salt (AQS). The addition of 1% AQS
had no clear effect on the yield of carbohydrates,
whereas the addition of 1% BH resulted in an
average yield increase of about 3%, similar to
the yield obtained by increasing the AQ charge
from 0.1 to 1%. The yield increase was mostly
due to stabilization of cellulose, although xylan
was also preserved to some extent. The intrinsic
viscosity of unbleached pulps derived from low-
intensity autohydrolysis (log Pxs
< 4.25) was
similar to the viscosity of pulp produced from
untreated wood. At higher extraction intensities
the viscosity rapidly decreased, reaching a
minimum slightly above 100 ml/g. The addition
of stabilizing agents against peeling had little
effect on pulp viscosity.
The soda-AQ cooks of untreated and PHWE-
treated birch sawdust were conducted under
varying conditions: i.e., alkali charge 18, 20, and
22% on o.d. feedstock, AQ charge 0.1% on o.d.
feedstock, cooking time 90, 120, and 150 min,
temperature 170 °C, and liquor-to-feedstock
ratio 5 l/kg. Pulp yields of the soda-AQ-cooks
are presented in Table 4.
Figure 11. (a): Oligomer concentrations in water solution after supercritical water treatment, analyzed by
HPAEC-PAD in aqueous solution (PA100 column). (b): Molar mass distributions of the solid precipitate fraction.
Analyzed by GPC-RI system (4 x PL-mixed A columns) after dissolution in anhydrous 90 g/L LiCl/DMAc.
a) b)
Figure 12. Cumulative yields of main birch components in wood residue after hot water extraction (a) and in
the pulp after soda-AQ pulping (b), plotted as a function of hot water extraction intensity (Log Pxs
).
a) b)

Clearly higher yields were achieved with the
reference material (untreated birch sawdust)
compared to the pressurized hot water extracted
materials. On the other hand, the colour of the
pulp produced from PHW extracted feedstocks
was clearly lighter (visible difference). Clearly
lower kappa numbers were achieved with pulps
produced from the PHW extracted materials, as
seen in Table 5. As the table shows, the kappa
numbers were very low, especially when pulping
was conducted with pressurized hot water
extracted feedstocks (T, “treated”).
Cooking experiments were also conducted
using oxygen-enhanced alkali cooking with
untreated and PHW extracted birch and spruce
sawdust. The same cooking equipment was
used for the oxygen-alkali cooks as for soda-
AQ cooks. The cooking conditions were: alkali
charge 19% on o.d. feedstock, cooking time
30, 60, 90, 120, and 150 minutes, temperature
170 °C, and liquor-to-wood (L:W) ratio 5 l/
kg. The cooking liquor was first bubbled
with oxygen (for 5 minutes) and an oxygen
atmosphere was then created in the reactors
by an oxygen flow. The oxygen-alkali cooking
yields for both feedstocks are presented in
Table 6.
Again, clearly higher cooking yields were
achieved with the reference material (untreated
sawdust) when compared to the pressurized
hot water extracted materials. In general,
PHWE-treatment conducted before oxygen-
alkali cooking facilitated the defibration,
especially with birch sawdust. However, only
very slight improvement could be observed
in the case of spruce. Overall, spruce sawdust
was very poorly defibrated during oxygen-
alkali cooking experiments. Pulp reject after
screening (material not passing a 0.2-µm sieve,
% of cooking yield) is presented in Table 7.
Soda-AQ cooks of birch wood
18% NaOH 20% NaOH 22% NaOH
Time,
min
Ref PHWE* PHWE** Ref PHWE* PHWE** Ref PHWE* PHWE**
90 51.6 53.5 38.5 50.4 54.0 38.8 49.1 52.8 38.0
120 50.9 53.1 38.1 49.7 53.5 38.5 47.6 51.4 37.0
150 51.1 52.9 38.0 49.1 51.6 37.1 47.8 50.7 36.5
Table 4. Birch soda-AQ cooking yield.
*Cooking yield (% of material charged into the reactors). **Total cooking yield (% of oven-dry feedstock
before pre-treatment).
Time, min 18 % NaOH 20 % NaOH 22 % NaOH
90 (NT*)
90 (T*)
14.9
6.4
11.8
5.5
10.2
5.5
120 (NT)
120 (T)
13.3
5.8
11.1
5.4
9.8
5.5
150 (NT)
150 (T)
12.2
5.4
11.0
4.6
9.3
5.6
Table 5. Kappa numbers of the birch soda-AQ pulp samples.
*NT= not treated (i.e., no PHWE), T= treated

4.5 Separation and purification of
hemicellulose-rich extracts
Hemicellulose-rich wood extracts after PHWE
contain relatively large amounts of water
and impurities which need to be removed
before further utilization. Membrane filtration
is a convenient method for simultaneously
concentrating and fractionating the extract.
Pilot scale membrane filtration equipment
(Figure 13) was used to separate high-molar-
mass hemicelluloses from the PHWE extracts.
The results from several concentration
filtration experiments performed at the pilot
scale revealed that concentration of wood
extracts to produce a high-molar-mass
hemicellulose fraction can be done using
a relatively high filtration capacity (flux)
without any pre-treatment when a hydrophilic
Oxygen-alkali cooks
Birch Spruce
19% NaOH 19% NaOH
Time, min Ref PHWE* PHWE** Ref PHWE* PHWE**
30
60
90
120
150
59.5
56.8
55.4
54.1
51.2
59.7
54.7
52.4
52.3
50.0
42.9
39.3
37.9
37.6
36.0
67.9
63.5
60.3
58.3
57.4
74.4
70.3
66.2
63.8
61.3
56.2
53.1
50.0
47.7
46.3
Table 6. Spruce and birch oxygen-alkali cooking yields.
*Cooking yield (% of material charged into the reactor). **Total cooking yield (% of oven-dry feedstock
before pre-treatment).
Time (min) Birch (Ref) Birch (PHWE) Spruce (Ref) Spruce (PHWE)
30 70.2 29.9 86.0 82.6
60 68.9 11.5 85.4 79.9
90 64.6 3.8 81.5 76.6
120 57.9 1.7 81.0 75.8
150 47.2 ND 80.7 73.4
Table 7. Pulp reject (% of cooking yield) after oxygen-alkali cooking.
Figure 13. Cross-rotational (CR)-350 ultrafiltration
equipment, membrane area 1 m2
.
ultrafiltration (10 kDa) regenerated cellulose
membrane is used and filtration is performed
using a high shear rate filter. High volumes of
water and small compounds can be removed
from the extract with a reasonable filtration

capacity (> 100 kg/(m2
h)) (Figure 14). The flux
gradually decreased as the feed concentration
increased, which could be expected. However,
at a certain point the flux suddenly collapsed
(Figure 14). Changes in the feed composition
due to increasing concentration, i.e. increased
total solids content and average molar mass of
compounds present in the feed, may have led
to an increase in osmotic pressure difference
across the membrane and increased viscosity.
In addition, the rheological properties of
the feed may have changed as a result of
concentration. These combined factors may
have led to the considerable and rapid flux
reduction. It was found that the filtration
capacity (flux) can be maintained at a good level
(about 95 kg/(m2
h)) if the pressure is increased
in line with the reduction in feed volume (i.e.
increase in concentration) at least until the TDS
of the concentrated fraction is about 8% (Figure
14). This was demonstrated in the experiments
in which spruce extract (TDS content 0.86%)
was fractionated in constant flux mode, where
the filtration pressure increased from 1.3 bar to
2.5 bar (60 °C, circumferential velocity of rotors
8.6 m/s), indicating that the decrease in filtration
capacity occurring at the end of concentration
filtration can be compensated by increased
filtration pressure. Despite the significant flux
decline seen at the end of the concentrate
filtrations, the membranes were not significantly
fouled and filtration capacity was easy to restore
with simple alkaline cleaning.
Several pre-treatments for improving the
filtration capacity and increasing the purity
of the resulting hemicellulose fractions were
investigated. For instance, a combination
of pre-treatment, ultrafiltration and post-
treatment was studied at laboratory scale
using a 40 cm2
RC70PP membrane with a 10
kDa cut-off. Spruce extract was first oxidized
and then ultrafiltered and diafiltered at 60 °C
and 2 bar. As Figure 15 shows, the combined
purification and separation steps removed
significant amounts of impurities from the
extract, although some hemicellulose losses
occurred in the process.
Figure 14. Filtration capacity in the treatment of spruce extract with the RC70PP membrane and
the CR-350 filter using constant pressure and constant flux filtration modes. Both experiments were
conducted at 60 °C with a rotor circumferential velocity of 8.6 m/s.

0.0
0.5
1.0
1.5
2.0
2.5
3.0
0
20
40
60
80
100
120
140
160
180
200
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
Pressure(constantfluxmode),bar
Flux(60°C),kg/(m2h)
Time, h
Constant
pressure
(2
bar) Constant
flux Pressure
at
constant
flux
mode
TDS(feed) 0.86%
Constant
pressure
mode
TDS
3.85% at
2.7
h
Constant
flux
mode
TDS
3.79% at
4.8
h

4.6 Analytical methods for compositional
and structural analyses
In order to evaluate the efficiency of the
developed processes, the composition of the
obtained fractions must be analysed. This
is important for determining the purity and
mass balance of the fractions. In addition to
composition, the structural features of the
biomass fractions must also be examined in
order to evaluate the applicability and value of
the material. The choice of analytical techniques
depends on the sample matrix. In addition,
appropriate pre-treatments must also be
applied. The most important analytical methods
for the research challenges described above are
Solid wood and fibrous samples Obtained information
Pre-treatment: grinding and sieving
Carbohydrate content and composition
- Acid methanolysis/GC Hemicelluloses and uronic acids
- Acid hydrolysis (two-stage)-HPAEC/PAD Cellulose and hemicelluloses
Extractives content and composition
- Extraction by ASE, Soxtec, Soxhlet with aceto-
ne, gravimetric detection
Total amount of (acetone soluble) extractives
- Group analysis with short GC column Quantitation of compound groups
- Analysis by GC-FID/GC-MSD Identification of individual components
Lignin amount (after extraction)
- Acid hydrolysis, gravimetric analysis of residue
+ UV detection of the hydrolysate
Total lignin as Klason lignin + acid soluble lignin
Molar mass
- Dissolution (multi-step) in DMAc/LiCl - HPSEC Molar mass distribution of cellulose (+hemicellu-
loses), calculated average values
Table 8. Analysis methods for solid wood and fibrous samples.
ASE: Accelerated Solvent Extraction, FID: Flame Ionisation Detector, GC: Gas Chromatography, HPAEC:
High Performance Anion Exchange Chromatography, HPSEC: High Performance Size Exclusion
Chromatography, MSD: Mass Spectroscopic Detector, PAD: Pulse Amperometric Detector, UV: Ultraviolet.
Figure 15. Chemical composition of original spruce extract before separation and purification (a) and
chemical composition of the concentrate after oxidative pre-treatment, ultrafiltration and diafiltration (b).
b)a)

listed in Tables 8, 9 and 10 for different sample
matrices, including a brief description of the
method and the information obtained. The
methods suggested for solid wood and fibrous
samples are based on either standard methods
or literature.
Molar mass is one of the most crucial criteria
for determining hemicellulose quality. Lignin is
always present in the hemicellulose fractions
either as such or linked to carbohydrates. This
causes problems in molar mass analysis using
universal calibration with light scattering-
based detection due to autofluorescence.
Because of the challenges related to this critical
measurement, a comparison between several
methodologies was performed using hot-
water extracted spruce galactoglucomannans
(GGM) and birch glucuronoxylans as substrates
(Xu et al. 2013). Four different size exclusion
chromatography (SEC) configurations used
by different partners were compared. Ethanol
precipitations were carried out on the birch
and spruce extracts to explore the effect of
lignin content on molar mass.
The difference in Mw values of the birch samples
was found to be relatively larger than that of
the spruce samples, presumably because
the birch extracts contained more lignin than
spruce. The difference in Mw values before
and after ethanol precipitation was similarly
ascribed to differences in lignin content of the
birch and spruce samples. In addition, the Mw
values determined by RI increased during the
precipitation–dissolution cycle, probably due
to aggregation. It was therefore not possible to
identify an optimal method for all sample types.
Another analytical challenge related to
hemicelluloses is the identification and
quantitation of individual oligosaccharides,
either in their native form or in altered form
during processing. By combining several
chromatographic and mass spectroscopic
techniques, it was possible to follow the
formation of cello-oligosaccharides from
cellulose under supercritical water treatment
conditions (Tolonen et al. 2014). The other
methods mentioned in Table 9 are based on
literature.
Lignin was partly extracted in the PHWE
treatments along with hemicelluloses as
an impurity. However, lignin is a valuable
component in itself with a range of potential
applications. The structure and properties
of lignin depend on its origin (raw material
and process). The methods listed in Table 10
provide useful information for evaluating the
quality and properties of isolated lignins.
5. Exploitation plan and impact of
results
The main objective was to generate a concept
based on pressurized hot water extraction
(PHWE) for producing high-molar-mass
hemicelluloses at high yield from wood of
varying particle size. Another goal was to
utilize the remaining fibre fraction after PHWE
for the production of new fibre products and
regenerated cellulose. Because no entirely
pure fractions can be separated from wood,
comprehensive studies of separation and
purification technologies required for these
processes were also carried out. Furthermore,
fundamental understanding of the factors
affecting PHWE and subsequent delignification
processes is needed for developing industrial-
scale processes. These general objectives
were met and the processes and knowledge
generated can be implemented, at least in
part, in industry. As a result, increased use
of biomass instead of oil for materials and
products will have a positive impact on society
and contribute towards a sustainable future.

PHWE extracts and isolated hemicelluloses Obtained information
Solids content, gravimetric Total amount of dissolved material
Carbohydrate content and composition
- Freeze-drying-acid methanolysis/GC Hemicelluloses and uronic acids
- Weak acid hydrolysis-HPAEC/PAD Hemicelluloses
Lignin amount
- Acidic solutions: direct UV detection or freeze-drying
- acetyl bromide or Klason lignin
Content of dissolved lignin
Acetic acid / formic acid, degree of acetylation
- HPLC, CE or benzylation-GC/MS Content of volatile acids
- Alkaline hydrolysis + analysis of acetic acid Degree of acetylation
Furfural-type degradation products
- HPLC or CE Content of furfural and hydroxymethylfurfural (HMF)
Other degradation products
- Silylation-GC/MS (Hydroxy)acids
Molar mass distribution of dissolved hemi and lignin
- HPSEC-various detectors* Molar mass distribution and calculated average values
Oligosaccharides
- HPAEC-PAD/MSQ** Quantitative analysis of oligosaccharides if standards
available, otherwise tentative identification by MSQ
(as deacetylated analogues)
- MALDI-TOF-MS, AP-MALDI-MS/MS, ESI-MS/MS** Identification including native acetylation
Table 9. Analysis methods for PHWE extracts and isolated hemicelluloses.
AP: Atmospheric Pressure, CE: Capillary Electrophoresis, ESI: Electron Spray Ionisation, HPLC: High
Performance Liquid Chromatography, MALDI: Matrix Assisted Laser Desorption Ionisation, MS: Mass
Spectrometry, MSQ: Quadrupole Mass Spectrometry, TOF: Time of Flight, other abbreviations as in Table
8. * For method comparison, see text above and ref. Xu et al. 2013. ** For application example and details,
see text above and ref. Tolonen et al. 2014.
Isolated lignin Obtained information
Composition
- Ash content (metals) by incineration Organic content
- Carbohydrate content: hydrolysis and HPAEC/PAD Lignin-Carbohydrate Complexes (LCC)
Structure
- Derivatisation-31
P NMR Frequency of hydroxyl functionalities
- 1D and 2D NMR techniques Substructures and inter-unit linkages
- Pyrolysis-GC/MS Fingerprint, mainly for sample comparison
Molar mass
- HPSEC-UV in NaOH Molar mass distribution
Elemental analysis (CHONS) Elemental composition
Thermal properties
- Glass transition temperature by DSC, degradation
by TGA
Transitions and degradation as a function of tempe-
rature
Table 10. Analysis methods for isolated lignin.
CHONS: Carbon, Hydrogen, Oxygen, Nitrogen and Sulfur, DSC: Differential Scanning Calorimetry, NMR:
Nuclear Magnetic Resonance, TGA: Thermogravimetric Analysis, other abbreviations as in Tables 8 and 9.

6. Networking
The research was carried out jointly by Aalto University, the Finnish Forest Research Institute,
Lappeenranta University of Technology, University of Helsinki, University of Jyväskylä, VTT Technical
Research Centre of Finland, Åbo Akademi University and Finnish Bioeconomy Cluster companies.
Table 11 presents the research partners and their roles.

Table 11. Partner organizations and their research roles.
Work package partners Role of the participating organization
Aalto University Pressurized hot water extraction, near- and
supercritical water treatment, delignification
Andritz Industrial tutor
Finnish Forest Research Institute Pressurized hot water extraction, purification,
delignification
Kemira Work Package Coordinator
Lappeenranta University of Technology Membrane filtration, separation, purification
Metsä Fibre Industrial tutor
Stora Enso Industrial tutor
University of Helsinki Enzymatic hydrolysis, analytical methods
University of Jyväskylä Delignification, characterization of black liquor
UPM-Kymmene Industrial tutor
VTT Pressurized hot water extraction, analytical
methods, enzymatic hydrolysis, modelling,
delignification, green liquor extraction
Åbo Akademi University WP leader. Pressurized hot water extraction,
analytical methods, purification, reaction
kinetics, hydrolysis by heterogeneous
catalysis, chemical characterization,
delignification

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