Forest Biomass Resources and Technological Prospects for the Production of Second-generation Biofuels in Finland by 2020

Introduction of second-generation biofuels is an essential factor for meeting the EU’s 2020 targets for renewable energy in the transport sector and enabling the more ambitious targets for 2030. Finland’s forest industry is strongly involved in the development and commercialising of second-generation biofuel production technologies. The goal of this paper is to provide a quantified insight into Finnish prospects for reaching the 2020 national renewable energy targets and concurrently becoming a large-scale producer of forest biomass based second-generation biofuels feeding the increasing demand in European markets. The focus of the paper is on assessing the potential for utilising forest biomass for liquid biofuels up to 2020. In addition, technological issues related to the production of second-generation biofuels were reviewed. Finland has good opportunities to realise a scenario to meet 2020 renewable energy targets and for large-scale production of wood based biofuels. In 2020, biofuel production from domestic forest biomass in Finland may reach nearly a million ton (40 PJ). With the existing biofuel production capacity (20 PJ/yr) and national biofuel consumption target (25 PJ) taken into account, the potential net export of biofuels from Finland in 2020 would be 35 PJ, corresponding to 2–3% of European demand. Commercialisation of second-generation biofuel production technologies, high utilisation of the sustainable harvesting potential of Finnish forest biomass, and allocation of a significant proportion of the pulpwood harvesting potential for energy purposes are prerequisites for this scenario. Large-scale import of raw biomass would enable remarkably greater biofuel production than is described in this paper.

The effects of location, feedstock availability, and supply-chain logistics on the greenhouse gas emissions of forest-biomass energy utilization in Finland

Forest biomass represents a geographically distributed feedstock, and geographical location affects the greenhouse gas (GHG) performance of a given forest-bioenergy system in several ways. For example, biomass availability, forest operations, transportation possibilities and the distances involved, biomass end-use possibilities, fossil reference systems, and forest carbon balances all depend to some extent on location. The overall objective of this thesis was to assess the GHG emissions derived from supply and energy-utilization chains of forest biomass in Finland, with a specific focus on the effect of location in relation to forest biomass’s availability and the transportation possibilities. Biomass availability and transportation-network assessments were conducted through utilization of geographical information system methods, and the GHG emissions were assessed by means of lifecycle assessment. The thesis is based on four papers in which forest biomass supply on industrial scale was assessed. The feedstocks assessed in this thesis include harvesting residues, smalldiameter energy wood and stumps. The principal implication of the findings in this thesis is that in Finland, the location and availability of biomass in the proximity of a given energyutilization or energy-conversion plant is not a decisive factor in supply-chain GHG emissions or the possible GHG savings to be achieved with forest-biomass energy use. Therefore, for the greatest GHG reductions with limited forest-biomass resources, energy utilization of forest biomass in Finland should be directed to the locations where most GHG savings are achieved through replacement of fossil fuels. Furthermore, one should prioritize the types of forest biomass with the lowest direct supply-chain GHG emissions (e.g., from transport and comminution) and the lowest indirect ones (in particular, soil carbon-stock losses), regardless of location. In this respect, the best combination is to use harvesting residues in combined heat and power production, replacing peat or coal.

Effect of forest-based biofuels production on carbon footprint, Case: Integrated LWC paper mill

International energy and climate strategies also set Finland’s commitments to increasing the use of renewable energy sources and reducing greenhouse gas emissions. The target can be achieved by, for example, increasing the use of energy wood. Finland’s forest biomass potential is significant compared with current use. Increased use will change forest management and wood harvesting methods however. The thesis examined the potential for integrated pulp and paper mills to increase bioenergy production. The effects of two bioenergy production technologies on the carbon footprint of an integrated LWC mill were studied at mill level and from the cradle-to-customer approach. The LignoBoost process and FT diesel production were chosen as bioenergy cases. The data for the LignoBoost process were obtained from Metso and for the FT diesel process from Neste Oil. The rest of the information is based on the literature and databases of the KCL-ECO life-cycle computer program and Ecoinvent. In both case studies, the carbon footprint was reduced. From the results, it can be concluded that it is possible to achieve a fossil-fuel-free pulp mill with the LignoBoost process. By using steam from the FT diesel process, the amount of auxiliary fuel can be reduced considerably and the bark boiler can be replaced. With a choice of auxiliary fuels for use in heat production in the paper mill and the production methods for purchased electricity, it is possible to affect the carbon footprints even more in both cases.

Developing markets of energy biomass – local and global perspectives

The thesis explores global and national-level issues related to the development of markets for biomass for energy. The thesis consists of five separate papers and provides insights on selected issues. The aim of Paper I was to identify methodological and statistical challenges in assessing international solid and liquid biofuels trade and provide an overview of the Finnish situation with respect to the status of international solid and liquid biofuels trade. We found that, for the Finnish case, it is possible to qualify direct and indirect trade volumes of biofuels. The study showed that indirect trade of biofuels has a highly significant role in Finland and may be a significant sector also in global biofuels trade. The purpose of Paper II was to provide a quantified insight into Finnish prospects for meeting the national 2020 renewable energy targets and concurrently becoming a largescale producer of forest-biomass-based second-generation biofuels for feeding increasing demand in European markets. We found that Finland has good opportunities to realise a scenario to meet 2020 renewable energy targets and for large-scale production of wood-based biofuels. The potential net export of transport biofuels from Finland in 2020 would correspond to 2–3% of European demand. Paper III summarises the global status of international solid and liquid biofuels trade as illuminated by several separate sources. International trade of biofuels was estimated at nearly 1 EJ for 2006. Indirect trade of biofuels through trading of industrial roundwood and material by-products comprises the largest proportion of the trading, with a share of about two thirds. The purpose of Paper IV was to outline a comprehensive picture of the coverage of various certification schemes and sustainability principles relating to the entire value-added chain of biomass and bioenergy. Regardless of the intensive work that has been done in the field of sustainability schemes and principles concerning use of biomass for energy, weaknesses still exist. The objective of Paper V was to clarify the alternative scenarios for the international biomass market until 2020 and identify the underlying steps needed toward a wellfunctioning and sustainable market for biomass for energy purposes. An overall conclusion drawn from this analysis concerns the enormous opportunities related to the utilisation of biomass for energy in the coming decades.

Greenhouse gas emissions from peat and biomass-derived fuels, electricity and heat — Estimation of various production chains by using LCA methodology

More discussion is required on how and which types of biomass should be used to achieve a significant reduction in the carbon load released into the atmosphere in the short term. The energy sector is one of the largest greenhouse gas (GHG) emitters and thus its role in climate change mitigation is important. Replacing fossil fuels with biomass has been a simple way to reduce carbon emissions because the carbon bonded to biomass is considered as carbon neutral. With this in mind, this thesis has the following objectives: (1) to study the significance of the different GHG emission sources related to energy production from peat and biomass, (2) to explore opportunities to develop more climate friendly biomass energy options and (3) to discuss the importance of biogenic emissions of biomass systems. The discussion on biogenic carbon and other GHG emissions comprises four case studies of which two consider peat utilization, one forest biomass and one cultivated biomasses. Various different biomass types (peat, pine logs and forest residues, palm oil, rapeseed oil and jatropha oil) are used as examples to demonstrate the importance of biogenic carbon to life cycle GHG emissions. The biogenic carbon emissions of biomass are defined as the difference in the carbon stock between the utilization and the non-utilization scenarios of biomass. Forestry-drained peatlands were studied by using the high emission values of the peatland types in question to discuss the emission reduction potential of the peatlands. The results are presented in terms of global warming potential (GWP) values. Based on the results, the climate impact of the peat production can be reduced by selecting high-emission-level peatlands for peat production. The comparison of the two different types of forest biomass in integrated ethanol production in pulp mill shows that the type of forest biomass impacts the biogenic carbon emissions of biofuel production. The assessment of cultivated biomasses demonstrates that several selections made in the production chain significantly affect the GHG emissions of biofuels. The emissions caused by biofuel can exceed the emissions from fossil-based fuels in the short term if biomass is in part consumed in the process itself and does not end up in the final product. Including biogenic carbon and other land use carbon emissions into the carbon footprint calculations of biofuel reveals the importance of the time frame and of the efficiency of biomass carbon content utilization. As regards the climate impact of biomass energy use, the net impact on carbon stocks (in organic matter of soils and biomass), compared to the impact of the replaced energy source, is the key issue. Promoting renewable biomass regardless of biogenic GHG emissions can increase GHG emissions in the short term and also possibly in the long term.

Evaluating land-use related environmental impacts of biomass value chains for decision-support : Comparison and testing of methodologies proposed for environmental life cycle assessment

Life cycle assessment (LCA) is one of the most established quantitative tools for environmental impact assessment of products. To be able to provide support to environmentally-aware decision makers on environmental impacts of biomass value-chains, the scope of LCA methodology needs to be augmented to cover landuse related environmental impacts. This dissertation focuses on analysing and discussing potential impact assessment methods, conceptual models and environmental indicators that have been proposed to be implemented into the LCA framework for impacts of land use. The applicability of proposed indicators and impact assessment frameworks is tested from practitioners' perspective, especially focusing on forest biomass value chains. The impacts of land use on biodiversity, resource depletion, climate change and other ecosystem services is analysed and discussed and the interplay in between value choices in LCA modelling and the decision-making situations to be supported is critically discussed. It was found out that land use impact indicators are necessary in LCA in highlighting differences in impacts from distinct land use classes. However, many open questions remain on certainty of highlighting actual impacts of land use, especially regarding impacts of managed forest land use on biodiversity and ecosystem services such as water regulation and purification. The climate impact of energy use of boreal stemwood was found to be higher in the short term and lower in the long-term in comparison with fossil fuels that emit identical amount of CO2 in combustion, due to changes implied to forest C stocks. The climate impacts of energy use of boreal stemwood were found to be higher than the previous estimates suggest on forest residues and stumps. The product lifetime was found to have much higher influence on the climate impacts of woodbased value chains than the origin of stemwood either from thinnings or final fellings. Climate neutrality seems to be likely only in the case when almost all the carbon of harvested wood is stored in long-lived wooden products. In the current form, the land use impacts cannot be modelled with a high degree of certainty nor communicated with adequate level of clarity to decision makers. The academia needs to keep on improving the modelling framework, and more importantly, clearly communicate to decision-makers the limited certainty on whether land-use intensive activities can help in meeting the strict mitigation targets we are globally facing.

Metsäpolttoaineiden vesitiekuljetus proomukalustolla

Metsäpolttoaineiden käyttö kasvaa lämpö- ja voimalaitoksissa ja mahdollisissa biojalostamoissa. Metsäpolttoaineilla voidaan saavuttaa päästövähennyksiä korvaamalla päästöintensiivisempiä polttoaineita. Metsäpolttoaineen kysynnän kasvu suurkäyttöpaikoilla luo uusia vaatimuksia metsäbiomassan hankintaan. Metsäpolttoaineiden vesitiekuljetuksen sisältämiä logistiikkajärjestelmiä kehittämällä toimitusvarmuutta pystytään parantamaan ja hankintaa laajentamaan kustannustehokkaasti ja ympäristöystävällisesti. Kuljetuskokeilut antoivat uutta tietoa vesitiekuljetuksen sisältämästä hankinnasta. Lastikapasiteetti nykyisen kaltaisessa Eurooppa IIa -suurproomussa vaihtelee 1200 tonnista jopa 1800 tonniin (kosteus 40 %) riippuen tiivistymisestä ja proomun modifiointiasteesta. Metsähakkeen energiatiheys oli suurproomukuljetuksissa keskimäärin 1 MWh/i-m3, joka oli 25 % parempi kuin vertailun hakerekkakuljetuksissa. Vesitiekuljetuksen kustannukset olivat kuljetuskokeiluissa lastauksineen ja purkuineen 0,02 €/MWh/km, ollen noin 20 % ketjun kokonaiskustannuksista. Simuloinnin edullisimpien vesitiekuljetusvaihtoehtojen vaihteluvälin kustannukset olivat vastaavasti 0,013 - 0,026 €/MWh/km. Lastauksen ja purun kustannus oli 0,4 - 0,6 €/MWh ja vesitiekuljetus 0,9 - 2,0 €/MWh (100 km). Ketjun kokonaiskustannukset hakkuutähdehakkeelle vaihtelivat simuloinnin edullisimpien vaihtoehtojen perusteella välillä 10,8 - 12,1 €/MWh (30 km rekka, 100 km proomu). Kuljetusketjujen simuloinnin kustannukset osoittivat proomukuljetusketjun olevan kilpailukykyinen vaihtoehto hakerekkakuljetusketjulle kalustosta ja vuosittaisista käyttötunneista riippuen kuljetusetäisyyden ylittäessä 100 km. Kustannustehokkain ratkaisu vesitiekuljetuksessa saavutettiin pienen aluksen ja suuren kokoluokan proomuyksikön kytkyeellä. Haketus kannattaa toteuttaa ennen proomukuljetuksen osuutta metsähakkeen paremman tiiviyden ja käsiteltävyyden perusteella. Logistiikkajärjestelmiä pitää kehittää tapauskohtaisesti käyttöpaikan tarpeet ja olosuhteet huomioon ottaen. Metsäpolttoaineiden vesitiekuljetuksen sisältämän logistiikan liiketoimintamallien vertailussa arvioitiin vaihtoehtoiset ulkoistetut toimintamallit paremmaksi kuin nykyinen urakointimalli. Tämä mahdollistaa paremman metsähakkeen saatavuuden ja logistiikan tehokkuuden lastausterminaaleissa. Terminaalitoiminnot ja proomukuljetukset lisäävät uusia liiketoimintamahdollisuuksia ja mahdollistavat metsäpolttoaineiden

Pyrolyysiöljyn valmistus Suomessa kotimaisista raaka-aineista

Tämän kandidaatintyön tarkoituksena on selvittää pyrolyysiöljyn tuotantomahdollisuuksia metsäbiomassasta Suomessa. Työssä käydään läpi olennaisia tuotantotekniikoita ja pohditaan tuotantolaitoksen mahdollista sijoituspaikkaa. Lisäksi tehdään karkea laskenta yksittäisen laitoksen ideaalisesta vuosikapasiteetista ja verrataan tulosta olemassa olevasta laitoksesta saatuihin tietoihin.

Sähkö- ja lämpöenergian tuotantomenetelmien ympäristöllisen kilpailukyvyn määrittäminen alueellista energiajärjestelmää suunniteltaessa

Työssä tarkasteltiin sähkö- ja lämpöenergian tuotantomenetelmien ympäristöllistä kilpailukykyä osana yhdyskunnan energiajärjestelmää. Sähkö- lämpöenergian tuotantomenetelmiä vertailtiin keskenään aiheutuvien kasvihuonekaasupäästöjen perusteella. Tarkastelu toteutettiin elinkaariarviointimenetelmällä. Työssä mallinnettiin pääasiassa uusiutuviin energialähteisiin perustuvia menetelmiä yhdyskunnan vuotuisen sähkö- ja lämpöenergiantarpeen täyttämiseksi. Elinkaariarviointimallin avulla vertailtiin keskenään aurinko- ja tuulisähköpainotteista ja CHP-painotteista energiajärjestelmää. Lisäksi työssä arvioitiin aurinko- ja tuulisähköntuotantoa sekä CHP-tuotantoa nettoenergianäkökulmasta. Työn tulosten pohjalta voidaan olettaa, että kokonaisvaltaisesti paras energianhankintavaihtoehto on usean eri sähkö- ja lämpöenergiantuotantomenetelmän yhdistelmä. Alhainen päästötaso tietyssä kategoriassa on yhdentekevää, jos energiaa ei ole saatavissa silloin, kun sitä tarvitaan. Lisäksi on tärkeää huomata, että uusiutuvien energialähteiden hyödynnettävyys riippuu vahvasti alueellisista erityispiirteistä, kuten aurinko- ja tuuliolosuhteista. Tästä johtuen kestävän energiajärjestelmän suunnittelussa alueellisten ominaisuuksien huomiointi on tärkeää. Mikä tietyllä alueella osoittautuu parhaimmaksi ratkaisuksi, ei välttämättä ole sitä toisenlaisessa ympäristössä.

Metsäenergian liiketoimintojen kehittäminen ja käytön kasvun vaikutukset Kaakkois-Suomessa

Kaakkois-Suomen alueella uusiutuvan energian käyttö ja erityisesti metsäenergian käyttö on kasvanut merkittävästi 2000-luvulla. Tulevaisuudessa metsäenergia nähdään edelleen potenti-aalisimpana vaihtoehtona korvattaessa fossiilisia polttoaineita lämpö- ja voimalaitoskokoluo-kassa. Muita uusiutuvan energian vaihtoehtoja ovat mm. tuuli- ja aurinkovoima, biokaasu sekä erilaiset kiinteät ja nestemäiset polttoainejalosteet. Tulevaisuudessa alueella voi olla mahdollis-ta tuottaa niin kansalliseen kuin kansainväliseen vientiin esim. biopolttonesteitä, biokaasua ja biohiiltä. Tutkimushankkeen tavoitteena oli selvittää metsäenergia-alan alueelliset toimijat sekä metsä-energian soveltuvuus ja liiketoimintamahdollisuudet Kaakkois-Suomen alueen energian tuo-tannossa. Tutkimus koostui seuraavista osatehtävistä: metsäsektorin toimijakentän kartoitus, metsäenergian alueelliset liiketoimintamahdollisuudet, puuperäisten polttoainejalosteiden käyttö- ja liiketoimintamahdollisuudet, muiden uusiutuvien energialähteiden käyttömahdolli-suudet ja vaikutukset Kaakkois-Suomessa. Tutkimuksessa arvioitiin myös Kaakkois-Suomen metsäenergian hankinnan työllisyysvaikutuksia. Tutkimuksen ohjausryhmänä toimi Kaakkois-Suomen metsäenergianeuvottelukunta. Tutkimuksessa kyselytutkimuksella selvitettiin metsäenergian tuottajien ja käyttäjien mielipi-teitä ja kehittämiskohteita toimialalta. Kaakkois-Suomessa hyödynnettävistä uusiutuvista energialähteistä selvitettiin nykyinen käyttö sekä arvioitiin tulevaisuuden hyödyntämismah-dollisuuksia vuonna 2020. Nämä tulokset esitettiin Kaakkois-Suomen energiataseen avulla. Kaakkois-Suomessa uusiutuvista energialähteistä puupolttoaineilla on merkittävin rooli metsä-teollisuuden johdosta ja alueen metsäenergian käyttö voi kasvaa jopa 1,7 TWh:in, mikäli fos-siilisia energialähteitä korvataan edelleen voimalaitoksissa ja lämpökeskuksissa. Metsäenergian käytön kasvussa alueen kunnilla on merkittävä rooli. Viime vuosina erityisesti tuulivoiman tuotanto on kasvanut ja tulee kasvamaan edelleen. Samoin aurinkoenergian hyödyntäminen kiinteistökokoluokassa on lisääntynyt voimakkaasti. Lisäksi maakuntaan on suunnitteilla kiin-teiden, nestemäisten ja kaasumaisten polttoainejalosteiden tuotantolaitoksia. Toteutuessaan laitokset voivat lisätä metsäenergian käyttöä merkittävästi.

Metsäenergian käytön kasvun liiketoimintamahdollisuudet Kaakkois-Suomessa

Kaakkois-Suomessa (Kymenlaakson ja Etelä-Karjalan maakunnat) metsäenergian käytön kasvaessa on tullut tarve tarkastella käytön kasvua eri käyttäjien näkökulmasta sekä arvioida kasvaneen käytön luomia liiketoimintamahdollisuuksia alueen toimijoille. Tutkimuksen tavoitteena on selvittää metsäenergian nykyinen käyttö ja käytön kasvumahdollisuudet alueella. Metsäenergian käytön kasvumahdollisuuksia voidaan arvioida nykyisen energian tuotantorakenteen sekä energian tarpeen perusteella. Näiden tietojen pohjalta voidaan arvioida metsäenergian riittävyyttä, käytön laajentamista ja laajentamisen yhteydessä syntyviä liiketoimintamahdollisuuksia alueen metsäenergian hankinnassa mukana oleville toimijoille ja energian tuotannon pk-yrittäjille (mm. energiayrittäjät ja -osuuskunnat). Hankkeen toteutuksen yhteydessä valmistellaan laajempaa hankekokonaisuutta uusiutuvien paikallisten energiamahdollisuuksien hyödyntämiseksi ja liiketoiminnan kehittämiseksi alueella. Tutkimusten tavoitteena on luoda hyvinvointia ja liiketoimintamahdollisuuksia alueelle. Etelä-Karjalan ja Kymenlaakson maakuntien osalta tutkimus sisälsi seuraavat osatehtävät: metsäenergian nykyisen käytön selvittäminen käyttökohteittain ja polttoainelajeittain (hakkuutähteet, kannot, pienpuu), metsäenergian potentiaalisten käyttökohteiden selvittäminen, metsäenergian kuntakohtaisen saatavuuden selvittäminen polttoainelajeittain, metsäenergian käytön suhde saatavuuteen, metsäenergian ympärille liittyvien liiketoimintamahdollisuuksien tunnistaminen ja kartoittaminen sekä tulosten raportointi. Tutkimuksen tuloksina saatiin Etelä-Karjalan ja Kymenlaakson maakuntien kuntakohtaiset taseet metsäenergian kysynnän ja tarjonnan määristä sekä alaan liittyvistä työllisyys- ja liiketoimintamahdollisuuksista. Tutkimuksen toteutuksessa on tehty tiiviisti yhteistyötä Kaakkois-Suomen metsäkeskuksen kanssa. Tutkimuksen seurantaryhmänä toimi Kaakkois-Suomen metsäenergianeuvottelukunta. Tutkimuksessa on luotu toimintamalli alueellisen ja paikallisen metsäenergian käytön ja saatavuuden tarkastelua varten. Toimintamallilla voidaan esittää paikalliset mahdollisuudet metsäenergian hyödyntämiseksi ja liiketoimintamahdollisuuksien arvioimiseksi.

From emerging opportunities to successful business networks – evidence from bioenergy

Increasing renewable energy utilization is a challenge that is tried to be solved in different ways. One of the most promising options for renewable energy is different biomasses, and the bioenergy field offers numerous emerging business opportunities. The actors in the field have rarely all the needed know-how and resources for exploiting these opportunities, and thus it is reasonable to seize them in cooperation. Networking is not an easy task to carry out, however, and in addition to its advantages for the firms engaged, it sets numerous challenges as well. The development of a network is a result of several steps firms need to take. In order to gain optimal advantage of their networks, firms need to weigh out with whom, why and how they should cooperate. In addition, everything does not depend on the firms themselves, as several factors in the external environment set their own enablers and barriers for cooperation. The formation of a network around a business opportunity is thus a multiphase process. The objective of this thesis is to depict this process via a step-by-step analysis and thus increase understanding on the whole development path from an entrepreneurial opportunity to a successful business network. The empirical evidence has been gathered by discussing the opportunities of animal manure refinement to biogas and forest biomass utilization for heating in Finland. The thesis comprises two parts. The first part provides an overview of the study, and the second part includes five research publications. The results reveal that it is essential to identify and analyze all the steps in the development process of a network, and several frameworks are used in the thesis to analyze these steps. The frameworks combine the views of theory and practical experiences of empirical study, and thus give new multifaceted views for the discussion on SME networking. The results indicate that the ground for cooperation should be investigated adequately by taking account of the preconditions in all the three contexts in which the actors operate: the social context, the region and the institutional environment. In case the project advances to exploitation, the assets and objectives of the actors should be paired off, which sets a need for relationships and sub-networks differing in breadth and depth. Different relationships and networks require different kinds of maintenance and management. Moreover, the actors should have the capability to change the formality or strategy of the relationships if needed. The drivers for these changes come along with the changing environment, which causes changes in the objectives of the actors and this way in the whole network. Bioenergy as the empirical field of the study represents well an industrial field with many emerging opportunities, a motley group of actors, and sensitivity for fast changes.

Pressurized hot water flow-through extraction of birch wood

Effective processes to fractionate the main compounds in biomass, such as wood, are a prerequisite for an effective biorefinery. Water is environmentally friendly and widely used in industry, which makes it a potential solvent also for forest biomass. At elevated temperatures over 100 °C, water can readily hydrolyse and dissolve hemicelluloses from biomass. In this work, birch sawdust was extracted using pressurized hot water (PHWE) flow-through systems. The hypothesis of the work was that it is possible to obtain polymeric, water-soluble hemicelluloses from birch sawdust using flow-through PHW extractions at both laboratory and large scale. Different extraction temperatures in the range 140–200 °C were evaluated to see the effect of temperature to the xylan yield. The yields and extracted hemicelluloses were analysed to obtain sugar ratios, the amount of acetyl groups, furfurals and the xylan yields. Higher extraction temperatures increased the xylan yield, but decreased the molar mass of the dissolved xylan. As the extraction temperature increased, more acetic acid was released from the hemicelluloses, thus further decreasing the pH of the extract. There were only trace amounts of furfurals present after the extractions, indicating that the treatment was mild enough not to degrade the sugars further. The sawdust extraction density was increased by packing more sawdust in the laboratory scale extraction vessel. The aim was to obtain extracts with higher concentration than in typical extraction densities. The extraction times and water flow rates were kept constant during these extractions. The higher sawdust packing degree decreased the water use in the extractions and the extracts had higher hemicellulose concentrations than extractions with lower sawdust degrees of packing. The molar masses of the hemicelluloses were similar in higher packing degrees and in the degrees of packing that were used in typical PHWE flow-through extractions. The structure of extracted sawdust was investigated using small angle-(SAXS) and wide angle (WAXS) x-ray scattering. The cell wall topography of birch sawdust and extracted sawdust was compared using x-ray tomography. The results showed that the structure of the cell walls of extracted birch sawdust was preserved but the cell walls were thinner after the extractions. Larger pores were opened inside the fibres and cellulose microfibrils were more tightly packed after the extraction. Acetate buffers were used to control the pH of the extracts during the extractions. The pH control prevented excessive xylan hydrolysis and increased the molar masses of the extracted xylans. The yields of buffered extractions were lower than for plain water extractions at 160–170 °C, but at 180 °C yields were similar to those from plain water and pH buffers. The pH can thus be controlled during extraction with acetate buffer to obtain xylan with higher molar mass than those obtainable using plain water. Birch sawdust was extracted both in the laboratory and pilot scale. The performance of the PHWE flow-through system was evaluated in the laboratory and the pilot scale using vessels with the same shape but different volumes, with the same relative water flow through the sawdust bed, and in the same extraction temperature. Pre-steaming improved the extraction efficiency and the water flow through the sawdust bed. The extracted birch sawdust and the extracted xylan were similar in both laboratory and pilot scale. The PHWE system was successfully scaled up by a factor of 6000 from the laboratory to pilot scale and extractions performed equally well in both scales. The results show that a flow-through system can be further scaled up and used to extract water-soluble xylans from birch sawdust. Extracted xylans can be concentrated, purified, and then used in e.g. films and barriers, or as building blocks for novel material applications.

Utilisation of biomass for energy production in the North-West Russian forest industry

Traditionally, fossil fuels have always been the major sources of the modern energy production. However prices on these energy sources have been constantly increasing. The utilization of local biomass resources for energy production can substitute significant part of the required energy demand in different energy sectors. The introduction of the biomass usage can easily be started in the forest industry first as it possesses biomass in a large volume. The forest industry energy sector has the highest potential for the fast bioenergy development in the North-West Russia. Therefore, the question concerning rational and effective forest resources use is important today as well as the utilization of the forestry by-products. This work describes and analyzes the opportunities of utilising biomass, mainly, in the form of the wood by-products, for energy production processes in general, as well as for the northwest Russian forest industry conditions. The study also covers basic forest industry processes and technologies, so, the reader can get familiar with the information about the specific character of the biomass utilization. The work gives a comprehensive view on the northwest forest industry situation from the biomass utilisation point of view. By presenting existing large-scale sawmills and pulp and paper mills the work provides information for the evaluation of the future development of CHP investments in the northwest Russian forest industry.