Användningen av cellulosa och lignin för prekursorfibrer (PF) för kolfibrer (CF) är ett mycket intressant forskningsområde på grund av den stora miljöpåverkan som dagens PF-fossilbaserade råvara PAN har. Denna avhandling fokuserar på att utveckla PF med ett kallt NaOH-upplösningssystem med cellulosakoncentrationer från 4,5 till 5,5 viktprocent med varierande massaviskositet och tillsats av lignin från 0-40 viktprocent jämfört med cellulosa. Koagulationssystemet som användes var ett fosforbaserat system med fosforsyra och ammoniumdivätefosfat (ADP) och tvätttiden ändrades för att undersöka påverkan på det slutliga oorganiska innehållet i PF. Effekten av tillsatt lignin och användning av en högre massaviskositet med en förändrad cellulosakoncentration undersöktes. Det som noterades av resultatet av dragegenskaperna och spinnbarheten hos dopen visar en viss trend som är att hög massaviskositet på 330 ml/g och hög ligninhalt på 40 viktprocent (i jämförelse med cellulosamängden i dopen) tycks uppvisa dålig spinnbarhet och svagare dragegenskaper. Användning av längre tvätttider under centrifugeringsprocessen resulterade i en lägre ask- och fosforhalt i PF. / The use of cellulose and lignin for precursor fibers (PFs) for carbon fibers (CFs) is a highly researched topic because of the large environmental impact that today’s PF raw material PAN which is fossil based. This thesis focuses of developing PFs with a cold NaOH dissolution system with cellulose concentrations ranging from 4.5 to 5.5 wt% with varying pulp viscosity and the addition of lignin ranging from 0-40 wt% in comparison to the cellulose. The coagulation system used was a phosphorus-based system with phosphoric acid and ammonium dihydrogen phosphate (ADP) and the washing time was altered to investigate the impact on the final inorganic content in the PF. The impact of the addition of lignin and using a higher pulp viscosity with an altered cellulose concentration is researched. What was noticed from the result of the tensile properties and the spinnability of the dope shows a certain trend which is that high pulp viscosity of 330 ml/g and a high lignin content of 40 wt% (in comparison to the cellulose amount in the dope) seems to present poor spinnability and weaker tensile properties. Using longer washing times during the spinning process resulted in a lower ash and phosphorus content in the PF.

The aluminium content of water extracts is an important aspect for the food safety of paper board, as the content indicates the ability of the paper board material to transfer aluminium to the packaged food product. Aluminium intake in humans and its health effects have been discussed for many years as some research has seen potential links between, among other things, high aluminium levels in the brain and the development of hereditary Alzheimer's.BfR's method and recommendation is the one that is generally followed by producers around the world, as there is no common international law. The method involves leaving small pieces of the paper board in Milli-Q water for 24 hours, before a content determination of Al is made in the formed water extract. In 2021, BfR halved its recommended limit for aluminium in aqueous extracts from 2 mg/L to 1 mg/L. For Stora Enso Skoghall, this led to some of their paper board grades not meeting this limit.A specific liquid packaging board grade that previously did not meet BfR's new limit was selected and alum as a flocculant was replaced with PAC, among other things. The aim was to investigate whether the change in flocculation chemical, as well as varying dosages, could affect the Al content in water extracts and whether PAC could possibly result in a lower Al content. The method for the water extracts and their effect on the final Al content have also been investigated further. This is done by performing the BfR method with artificial tap water as well, and then comparing the Al content in these extracts.PAC as a flocculant instead of alum did not result in lower levels of Al in the water extracts. Variations in dosage and production without aluminium-containing flocculants also did not significantly affect the Al content of the extracts. The type of water used in the analysis turned out to play a major role in how much aluminium migrated from the board. All samples extracted in artificial tap water resulted in Al levels less than the 1 mg/L limit. For the majority of the samples extracted in Milli-Q water, the Al levels were instead closer to 2 mg/L. The difference in Al content between the water extracts is believed to be mainly due to differences in pH and thus varying amounts of soluble aluminium.The results showed a relatively large variation between the two external laboratories used. This is believed to be mainly due to variations in method and measuring equipment, but one must also consider the small sample size that was tested and what variations it entails.

In this project, a numerical model describing the reaction mechanism and the mass and energy transport in wood pyrolysis is studied. The applicability of the model in predicting actual biomass pyrolysis assessed by comparing the model to TGA experimental measurements. The comparison to experiments is done in relation to the mass loss characteristics of chips of varying sizes. The mass loss is of interest as it is a variable necessary in the coupling of reactor and particle models. Three reaction models were simulated and results compared to experimental data, namely, the reaction model developed by Park et al. [Combustion and Flame 157 (2010) 481-494], a simple multicomponent parallel reaction model, and a competitive reaction model. The model of Park et al. did not fit with the experimental data as it underestimates the char yield. The parallel reaction model, which is based on hemicellulose and cellulose decomposition to char and volatiles, also did not agree with the experiments even when fitting the parameters to the data. The downward trend of char yield with increasing temperature suggests there exists competition between the volatiles and char in wood pyrolysis. The proposed competitive reaction model which consists of a hemicellulose reaction to volatiles and a cellulose reaction to volatiles and char is in good agreement with the experimental data. The mass loss characteristics in the experimental temperature range is fairly predicted within reasonable accuracy.

Through air drying (TAD) enables production of premium tissue products with increased softness, absorbency and bulk. On the other hand, the energy consumption of the TAD process is considerably higher than for conventional tissue drying alternatives. Previous studies on the TAD process have indicated that the drying rate for low grammage sheets is independent of the flow of air through the sheets.   The objective of this work has been to investigate and quantify how drying times and drying rates for low grammage sheets are affected by the addition of external web heating in a TAD process. Moist Eucalyptus and softwood sheets with grammages ranging from 15 to 60 g/m2 were dried in a laboratory process by an air flow through them and an IR-dryer with a variable power output. During drying, pressure drop and air flow were measured and an IR-camera recorded surface temperatures which enabled calculation of drying times and drying rates.   Using the IR-dryer to dry sheets shortened the drying time with at least 20 % and up to 60 % compared to sheets dried without IR-heating. Both pulp types and all grammages showed a linear relationship between drying times and the amount of evaporated water. Mass specific drying rates however, were very high for low grammage sheets and decreased rapidly with increasing grammage. Especially for low grammage sheets the drying rate had a very strong dependency on the IR-power and increased significantly with every increasing IR-power level. This finding implies that heat transfer could be a limiting factor when drying low grammage sheets in the TAD process. Another interesting phenomenon was observed for all grammages of the Eucalyptus sheets. Through these sheets the air flow rate increased with increasing IR-power, something that was not seen at all for the softwood sheets.   To summarize, adding external web heating to a TAD process resulted in a positive effect on drying times and drying rates, especially for low grammage sheets typical for the TAD process.

Syftet med detta examensarbete var att öka reaktiviteten hos förhydrolyserad kraftmassa genom att använda tidigare förhydrolysat och svavelsyra under förhydrolysen. Först bestämdes den kemiska sammansättningen av två olika vedråvaror (Acacia crassicarpa och Eucalyptushybrider) för att observera och korrelera med förhydrolysprocessen. Därefter studerades effekten av att för förhydrolyskraftkokning använda vatten, förhydrolysat och svavelsyra med olika koncentration under förhydrolysen vilket korrelerades med avlägsnandet av pentosan, utbyte, viskositet, kappanummer och ljushet. Därefter valdes en av vardera syrabaserad förhydrolyskraftmassa att blekas helt till dissolvingmassa för bestämning av Fock-reaktivitet, vilket jämfördes mot den vattenbaserade förhydrolysen som referens. Den slutliga kvaliteten på de olika förhydrolyskraftmassorna studerades också. Detta examensarbete visade att användandet av förhydrolysat och svavelsyra kan ge högre Fock-reaktivitet jämfört med vatten under liknande processförhållanden. Däremot gav syrabaserad förhydrolyskraftmassa lägre utbyte än vattenbaserad förhydrolyskraftmassa. Syrabaserad förhydrolyskraftkokning gav även lägre pentosanhalt, lägre halt extraktivämnen och lägre viskositetsvärden. Förhydrolysatbaserad förhydrolyskraftmassa hade värden mellan de som uppvisades av vattenbaserade- och svavelsyrabaserade förhydrolyskraftmassor. Dessutom hade förhydrolyskraftmassor från Eucalyptushybrider högre Fock-reaktivitet, lägre pentosanhalt, lägre halt extraktivämnen och högre viskositet än förhydrolyskraftmassor från Acacia crassicarpa. / The worldwide demand for dissolving pulp has been increasing significantly in Asia which is majorly produced from prehydrolysis kraft pulping and most of the prehydrolysis kraft pulp are consumed in viscose rayon production. Thus, it is interesting to have research in the process of prehydrolysis kraft pulping to make it a cleaner and more sustainable production. One of the most important qualities of prehydrolysis kraft pulp in viscose rayon is reactivity, which can lead to less chemical consumption and lower production cost. The aim of this research project is to increase the reactivity of prehydrolysis kraft pulp by using prehydrolysate and sulfuric acid during prehydrolysis cooking. Firstly, the wood chemical composition of two different hardwood species (Acacia crassicarpa and Eucalyptus hybrids) were determined and correlated with the prehydrolysis kraft pulping process. Secondly, prehydrolysis kraft cooking using water, prehydrolysate, and sulfuric acid with different concentration during prehydrolysis were studied and correlated with pentosan removal, yield, viscosity, kappa number, and brightness. Later, one of each acid based prehydrolysis kraft pulping were chosen to be proceed to fully bleached dissolving pulp for determining Fock reactivity which was compared to water prehydrolysis kraft pulping as the reference. The final quality of different prehydrolysis kraft pulps were also studied. From this research project, it showed that prehydrolysate and sulfuric acid prehydrolysis kraft pulp improved the Fock reactivity as compared to water prehydrolysis in similar pulping condition. However, acid based prehydrolysis kraft pulping gave lower yield than water prehydrolysis kraft pulping. Acid based prehydrolysis kraft cooking provided lower pentosan and extractive content, but lower viscosity values. Meanwhile, the prehydrolysate kraft pulp had the intermediate values between water and sulfuric acid prehydrolysis kraft pulping. In addition, Eucalyptus hybrids prehydrolysis kraft pulping had higher Fock reactivity, lower pentosan content, lower extractives, and higher viscosity than Acacia crassicarpa. To conclude, the more acidic prehydrolysis increased Fock reactivity with lower pulp yield, pentosan, extractive and viscosity.

Lignin är en av de vanligaste naturliga råvarorna på jorden och finns mestadels i trä. Nuförtiden är valoriseringen av lignin en av processutvecklingarna för teknologier inom massa- och pappersindustrin. Denna utveckling syftar till att öka värdet av lignin. Traditionellt förbränns genererat lignin, känt som tekniskt lignin, som bränsle i sodapannan som en del av svartlutskomponenter, och denna praxis är används kontinuerligt inom massa- och pappersindustrin. Syftet med detta examensarbete är att undersöka det tekniska ligninet från två specifika träslag, Acacia crassicarpa (Acra) och Eucalyptus Hybrids (Euca), för att öka kunskapen om det tekniska ligninet och hitta lämpliga tillämpningar för dessa råvaror i framtiden. I denna studie isolerades lignin från svartlut som genererats från två olika kokningsmetoder, kraftkokning- och kraftbased dissolvingkokning (KP och DP). Karakteriseringsmetoderna inkluderade molekylviktsfördelning (THF-SEC), analys av ligninets funktionella grupper med fosfor-31 Nuclear Magnetic Resonance (31P-NMR) kvantifiering och ligninets trukturella elementanalys via Two-Dimensional Heteronuclear Single Quantum Correlation NMR (2D-HSQC NMR). Utbytet erhållet från kraftkokning (KP) och kraftbased dissolvingkokning (DP) visade inga skillnader för samtliga prover och resultaten visas inom samma intervall (cirka 0,06-0,08 g/mol svartlut). Molekylviktsfördelningen för KP och DP-kokning ligger fortfarande inom intervallet för kraftlignin Mw (1500-5000 g/mol) och polydispersitetsindex (PDI) för KP hade ett högre värde än DP för båda typerna av undersökta råvaror. För de funktionella grupperna hade Eucalyptus Hybrids högre -OH-halt än Acacia crassicarpa oavsett kokningstyp. 31P-NMR kvantifieringsdata visade tydligt att KP-Euca innehöll den högsta halten av  alifatisk-OH (1,4 mmol/g). DP-Euca hade den högsta halten C5-kondenserad (2,5 mmol/g), medan den högsta mängden Guaiacyl-OH identifierades i DP-Acra (1,2 mmol/g). Fingeravtrycket av kopplingarna som kvantifierades från 2D-NMR HSQC visade att KP hade högre β-O-4', β-5' och β-β' interenhetskopplingar än DP. Dessutom hade Acacia crassicarpa en högre andel interenhetskopplingar än Eucalyptus Hybrids för båda kokmetoderna. De högsta β-O-4'-, β-5'- och β-β'-kopplingarna detekterades i KP-Acra med 3,4 %, 0,5 % respektiv 4,3 %. / Lignin is one of the most abundant natural raw materials on Earth and is mostly found in wood. Nowadays, the valorization of lignin is one of the continual process developments for technologies in the pulp and paper industry. This development is intended to increase the value of lignin. In the traditional approach, generated lignin known as technical lignin is burnt as fuel in the recovery boiler as part of black liquor components, and this practice is still common in the pulp and paper industry. The objective of this thesis work is to explore the technical lignin from specific wood species, Acacia crassicarpa (Acra) and Eucalyptus Hybrids (Euca), to emphasize the knowledge about the technical lignin and finding suitable application for the mentioned raw materials in the future. In this study, lignin was isolated from black liquor generated from two different cooking methods, kraft and kraft dissolving pulp cooking (KP and DP). The Characterization methods included molecular weight distribution by THF-SEC, lignin functional groups analysis via Phosphorus-31 Nuclear Magnetic Resonance (31P-NMR) quantification, and lignin structural elements analysis via Two-Dimensional Heteronuclear Single Quantum Correlation NMR (2D-HSQC NMR). The isolation yield obtained from kraft cooking (KP) and kraft dissolving pulp cooking (DP) did not have drastic differences for all the samples and therefore the results are within the same ranges (around 0.06-0.08 g/mol of black liquor). The molecular weight distribution values of KP and DP cooking are still within the range of kraft lignin Mw (1500-5000 g/mol) and the polydispersity index (PDI) of KP had a higher value than DP for both types of raw material investigated.  For the functional groups, Eucalyptus Hybrids had the higher -OH content than Acacia crassicarpa regardless of the cooking type. The 31P-NMR quantification data showed clearly that KP-Euca was the richest in Aliphatic-OH (1.4 mmol/g). DP-Euca had the greatest amount of C5-Condensed (2.5 mmol/g), while the highest amount of Guaiacyl-OH was identified in DP-Acra (1.2 mmol/g). The fingerprint of the linkages that was quantified from 2D-NMR HSQC showed that KP cooking had a higher β-O-4’, β-5’ and β-β’ interunit linkages than DP cooking. Furthermore, Acacia crassicarpa had a higher interunit linkages percentage than Eucalyptus Hybrids for both cooking methods. The highest β-O-4’, β-5’ and β-β’ linkages were detected in KP-Acra with 3.4 %, 0.5 %, and 4.3 % respectively.

Abstract The wood industries to this day use almost exclusively petroleum derived adhesives that are based mainly on the reaction of formaldehyde with urea, melamine or phenol. These adhesives have low cost and good adjustable properties which makes it hard for bio-based alternatives to compete. Phenol formaldehyde (PF), as an example of a synthetic adhesive, has been in use for over 100 years. In some parts of the world, legislation around formaldehyde is changing, and there is an increasingly voluntary awareness about the toxicity and unsustainability of formaldehyde. Industries realize that raw materials from oil is unstainable. The latter is currently a driving factor behind research on alternatives to amino based adhesives. Also, consumer interest in healthy and sustainable products, such as emitting less formaldehyde indoors, increases the need for bio based adhesives. Cellulose contained in plant cell walls is a renewable, abundant and nontoxic resource. During the last decades, many innovations have been achieved around cellulose and this trend does not seem to be slowing down. Cellulose shows excellent mechanical properties, high strength, high elastic modulus as well as having a low density. Research about cellulose reinforced adhesives has been increased the last years. This thesis studied the enhancement of phenol formaldehyde adhesive with Crystalline Nano Cellulose (CNC) at 5wt% and 10wt% loading levels for producing plywood boards. Indecisive results when using CNC higher than 3wt%, especially with PF resin, have been reported by other authors. In this thesis, European standards were applied. EN 314 was applied to test the panels shear strength. Three (3) treatment classes were selected, indoor room condition as well as pre-treatments 5.1.1 and 5.1.3. Other properties measured were modulus of elasticity, thickness swelling, formaldehyde emissions. Results showed a shear strength increase for all pre-treatment classes. 10wt% CNC mixture with phenol formaldehyde in water bath, pre-treatment (5.1.1) for 24h showed the highest increase in shear strength (+73,9%). The 10 wt% CNC mixture panels also showed the highest wood fibre failure of all panel types produced. A decrease in MOE has been observed with 10 wt% CNC compared to the 5 wt% CNC panels. Formaldehyde emissions tests were inconclusive, but since less PF was used, there was a general reduction in emissions. The 5 wt% CNC panels were superior in terms of modulus of elasticity and swelling and also showed improved shear strength.

Made available in DSpace on 2015-03-26T14:01:17Z (GMT). No. of bitstreams: 1 texto completo.pdf: 597170 bytes, checksum: b5393c045719ef7bc2a909daf913b77a (MD5) Previous issue date: 2014-06-26 / The pursuit of competitiveness in the current scenario of the pulp industries is a major challenge for companies. Join the efficiency in the process of implementation of forests, silviculture, harvesting, wood logisticsand pulp cellulose logistics results in a complex matrix in industries with high production capacity. The combination of large areas of forests, modern and efficient plants, good capacity for movement of raw materials and the production and relentless pursuit of low operating costs are almost always divergent factors. Fit management teams to conduct detailed each process relating them to the specific characteristics of the regions in which they operate, thus defining the best ways to deal with obstacles studies. Accordingly, this study was undertaken, in order to identify concepts aimed at maintenance efficiency in modern industry, always directed to the new reality of the sector, which is the deployment of high capacity, far from large industrial centers factories. Additionally were raised core services applicable to this type of industry and examined the relationship of efficiency with this new reality. Finally we tried to study various processes considered relevant for new pulp and relate factors focused on maintenance of equipment and facilities, such that focal points can be identified with possible action taken facing the pursuit of efficiency. The analysis of these factors was taken by professionals with experience in manufacturing pulp, beyond the requirements of the search for literature review and empirical evidence for processing of proposals relations. The study confirmed the need for an efficient structure maintenance in factories and allowed us to identify the degree of importance of maintenance planning in maintenance efficiency in pulp mills. / A busca da competitividade no atual cenário das indústrias de celulose é um grande desafio para as empresas do setor. Associar a eficiência nos processos de implantação de florestas, silvicultura, colheita, logística de madeira, produção de celulose e logística de celulose resulta em uma matriz complexa no caso de indústrias com alta capacidade de produção. A combinação de grandes áreas de florestas, fábricas modernas e eficientes, boa capacidade para movimentação de matéria prima e da produção e a busca incansável pelo baixo custo operacional são fatores quase sempre divergentes. Cabe às equipes de gestão a realização de estudos detalhados de cada processo relacionando-os com as características específicas das regiões em que atuam, definindo, assim as melhores formas de tratar os obstáculos encontrados. Nesse sentido, foi conduzido este estudo, com objetivo de identificar conceitos voltados à eficiência da manutenção na indústria moderna, sempre direcionados à nova realidade do setor, que é a implantação de fábricas de alta capacidade, longe dos grandes centros industriais. Associado a isto foram levantados os principais serviços aplicáveis a este tipo de indústria e verificada a relação de eficiência com esta nova realidade. Por fim procurou-se estudar diversos processos considerados relevantes para nova indústria de celulose e relacionar fatores voltados à manutenção dos equipamentos e instalações, de tal forma que possam ser identificados pontos focais com possíveis tomadas de ação voltadas a busca de eficiência. A análise destes fatores foi feita por profissionais com experiência no setor industrial de celulose, além da busca por requisitos da revisão de literatura e de evidências empíricas para tratamento das relações propostas. O estudo confirmou a necessidade de uma estrutura eficiente de manutenção nas fábricas e permitiu identificar o grau de importância do planejamento da manutenção na eficiência da manutenção nas fábricas de celulose.

La bioconversion des biomasses lignocellulosiques est actuellement un grand défi pour le développement de technologies de bio-raffinage. Le manque de connaissances des mécanismes de liquéfaction et de saccharification est l’un des principaux facteurs qui pénalisent le développement des procédés de bio-raffinage. Ce travail est centré sur le développement d’analyses physiques et biochimiques in-situ (viscosimétrie, focus beam reflectance measurement) et ex-situ (rhéometrie, granulométrie laser, morphogranulométrie, sédimentation…) pour améliorer la compréhension des mécanismes de déstructuration desfibres lignocellulosiques et caractériser les cinétiques de libération de carbone fermentescible. Des substrats modèles (cellulose microcristalline, papier Whatman) et industriels (pâte à papier, bagasse de canne à sucre) ont été utilisés avec différentes conditions d'hydrolyse (1% à 30%w/v, 0.1 à 0.5mL enzyme/ g cellulose). Les résultats obtenus ont permis:- de proposer et de valider les mesures in-situ de la viscosité de la suspension et de la distribution des longueurs de corde des particules, ainsi que sa conversion en distribution de diamètre.- de montrer l'impact de la nature et de la concentration de substrat et des ratios enzyme/substrat sur les évolutions des paramètres physico-biochimiques lors de l'hydrolyse. Ces effets ont été quantifiés sur les limitations de transfert.- d'établir un modèle phénoménologique de comportement rhéologique des suspensions initiales- de montrer que les cinétiques physico et bio-chimiques sont des cinétiques du second ordre- de montrer que, pour des hydrolyses à haute teneur en matière sèche, on peut réduire considérablement la limitation des transferts liée aux hautes concentrations et contrôler la cinétique de production de glucose par une stratégie d’ajouts cumulés desubstrat. / In the context of biofuels and chemicals production of petroleum substitutes from renewable carbon, bioconversion of lignocellulose biomasses is currently a major challenge. The limited knowledge of liquefaction and saccharification mechanisms stands as the main factor which penalizes bio-refinery progress. The present work is centred on the development of in-situ(viscosimetry, focus beam reflectance measurement) and ex-situ (rheometry, diffraction light scattered, morphometry, decantation…) physical and biochemical analysis to expand our understanding of the destructuration mechanisms of lignocellulose fibres and to characterise the release kinetics of fermentable cellulosic carbon. Model (microcrystalline cellulose,Whatman paper) and industrial (paper-pulp, sugarcane bagasse) lignocellulose matrices under a large range of hydrolysis conditions (1% up to 30%w/v and 0.1 up to 0.5mL enzyme/g cellulose) were studied during 24h hydrolysis experiments (pertinent period to appreciate transfer limitations). Our scientific results allow:- to propose and validate the in-situ measurements of the suspension viscosity and chord length distribution together with its conversion into particle size distribution.- to demonstrate the impact of the substrate nature and concentration and of the enzymatic ratios on the evolution of physical- and biochemical parameters during hydrolysis. Their impacts on transfer phenomena were quantified.- to establish phenomenological models for rheological behaviour of initial suspensions.- to describe all physical (viscosity, particle size) and biochemical (substrate and product) kinetics by second order reaction models.- to demonstrate that, for high dry matter concentration hydrolysis, a cumulative feeding substrate strategy allows considerably reducing the transfer limitations linked to high concentrations and to control the glucose production kinetics.

This work describes three alternative processes for producing microfibrillated cellulose (MFC) in which pulp fibres are first pre-treated and then homogenized using a high-pressure homogenizer. In one process, fibre cell wall delamination was facilitated with a combined enzymatic and mechanical pre-treatment. In the two other processes, cell wall delamination was facilitated by pre-treatments that introduced anionically charged groups into the fibre wall, by means of either a carboxymethylation reaction or irreversibly attaching carboxymethyl cellulose (CMC) onto the fibres. All three processes are industrially feasible and enable production with low energy consumption. Using these methods, MFC can be produced with an energy consumption of 500–2300 kWh/tonne, which corresponds to a 91–98% reduction in energy consumption from that presented in earlier studies. These materials have been characterized in various ways and it has been demonstrated that the produced MFCs are approximately 5–30 nm wide and up to several microns long. / <p>QC 20120928</p>