Delignifiering under sulfat koket innefattar både kemisk nedbrytning och fysisk upplösning av lignin, för vilket närvaron av oorganiska salter, oorganiska anjoner samt oorganiska katjoner (sammantaget benämnda som "Non-process elements", NPEs på engelska) kan ha inverkan på delignifieringens hastighet. Tidigare studier har funnit att ved med högt kalciuminnehåll är svårdelignifierad och att kalcium har potentiell inverkan på ligninlöslighet och kappatal. Att avlägsna kalcium från ved är svårt, men vissa studier har visat att detta kan motverka ovannämnda2(4)inverkan och öka delignifieringen. Denna studie har studerat effekten av kalcium under delignifieringen på fyra prover av Eucalyptus dunnii tagna från olika marktyper, åldrar, kalciumhalt samt geografisk plats (i Uruguay). Målet har varit att undersöka kalciumets inverkan under delignifieringen och dess effekt på massautbytet. Fyra satser av vardera vedmat erial kokades i stålautoklaver med följande parametrar: 18 % effektiv alkali, 35 % sulfiditet, 1 h impregnering vid 110 °C, 2,75 h, 3 h, 3,25 h respektive 3,5 h koktider (för vardera sats) vid 145 °C. Provet med den högsta kalciumhalten om 4668 mg/kg kunde dock inte delignifieras, vare sig vid dessa kokparametrar eller vid en temperaturökning till 155 °C och en resulterande H-faktor på 735 enheter – motsvarande 7 h koktid vid 145 °C – och analyserades inte vidare i studien. Resultaten visar på en negativ effekt från kalcium avseende både delignifieringshastighet och utbyte: Eucalyptus med en lägre kalciumhalt på 705 mg/kg gav massa med kappatal 13 efter kokning, medan eucalyptus med 1500 mg/kg kalcium efter samma kokning gav massa med kappatal 17. Motsvarande utbyte för dessa massor var 48 % för provet med lägre kalciumhalt och 46 % för provet med högre kalciumhalt. Kvantifiering av modifierat kappa och uronsyror bekräftade att ovannämnda effekter inte berodde på inverkan från hexennuronsyra i massan. / Delignification during sulphate cooking involves both chemical degradation and physical solubilization of lignin where the presence of non-process elements (NPEs), inorganic salts, anions or cations in the process could affect the rate of delignification. Previous studies also indicate that wood with higher calcium content is challenging to delignify which would affect the lignin solubility and increase kappa number. Besides, the removal of calcium from Eucalyptus is difficult. However, some study suggests that removal of calcium before the process increases the rate of delignification. This work studies the effect of calcium in four Eucalyptus dunnii samples of different soil type, age, different calcium content and Uruguayan geographical areas during the delignification process. The aim is to study the influence of calcium during the delignification in kraft cooking and its effects on pulp yield in Eucalyptus dunnii. Four batches of each material were cooked in a steel autoclaves with the following parameters: 18% effective alkali, 35% sulphidity, 1 h impregnation at 110 ° C, 2.75 h, 3 h, 3.25 h and 3.5 h cooking times, respectively (for each batch) at 145 ° C. Besides, sample with Ca-4668 mg/kg were not able to defibrate at common cooking conditions and even after altering the cooking conditions to higher temperature 155℃, H-Factor to be 735 (cooking time of 7 hours) and were not analyzed further in the study. Results suggest that there is a detrimental influence of calcium on delignification during the kraft cooking process, and it also affects the pulp yield in Eucalyptus dunnii. Eucalyptus with a lower calcium content of 705 mg / kg gave pulp with kappa number 13 after cooking, while eucalyptus at 1500 mg / kg calcium after the same cooking time gave pulp with kappa number 17. Corresponding yield for these pulps were 48% for the lower calcium sample and 46% for the higher sample calcium content. A slower rate of delignification with higher kappa number and lower overall pulp yield are the results of higher calcium content in Eucalyptus dunnii. Quantification of modified kappa and uronic acids confirm that the effect of calcium on kappa is due to residual lignin and not by the presence of hexenuronic acids.

Le miscanthus x Giganteus (MxG) constitue, du fait de sa composition, une source renouvelable de matière lignocellulosique pouvant être d'un grand intérêt pour la production de molécules à haute valeur ajoutée. Le MxG ayant servi à ce travail provient du lycée agricole à Courcelles-Chaussy, Metz-France. Sa teneur élevée en hémicelluloses (26 %), en lignine (26 %) et en cellulose (36 %) en fait une bonne source de polymères et de carburant renouvelable. L'étude que nous avons réalisée a été menée dans le but de caractériser la paille de MxG et d'optimiser le processus de délignification en une seule étape (1) par un traitement organosolv à l'éthanol et en deux étapes (2) par un prétraitement consistant en une autohydrolyse à l'eau/organosolv. Le procédé éthanol organosolv a permis un bon fractionnement des trois constituants de la biomasse (la lignine, la cellulose et les hémicelluloses). Le procédé de traitement en deux étapes, impliquant une autohydrolyse à l'eau (en présence et en l'absence du 2-naphtol), préalable au traitement organosolv, a permis de faciliter l'étape ultérieure de délignification en déstructurant la lignine. Une investigation portant sur la structure physico-chimique a été réalisée sur de la lignine de bois broyé et de la lignine organosolv de MxG extraite à différentes sévérités de traitement. Nous nous sommes ensuite intéressés à utiliser la lignine organosolv pour la formulation d'un adhésif pour le bois dans laquelle un aldéhyde non toxique et peu volatile (le glyoxal) est employé en remplacement du formaldéhyde. Une formulation, composée à 100 % de résines naturelles (60 % de tannins de mimosa et 40 % de lignine glyoxalée) a été utilisée pour la conception d'un panneau de particules et a donné des résultats prometteurs avec une force de liaison interne de 0,41 MPa, supérieure à la valeur de la norme européenne en vigueur. Enfin, une étude des propriétés antioxydantes a été faite sur les lignines extraites. Les résultats obtenus ont montré une corrélation entre l'activité antioxydante et les conditions opératoires du traitement organosolv, la masse moléculaire moyenne, l'indice de polydispersité et les groupements hydroxyles phénoliques des lignines. / Miscanthus x giganteus (MxG) is, because of its composition, a source of renewable lignocellulosic material that can be of great interest for the production of high added value molecules. MxG used in this work comes from the agricultural high school of Courcelles-Chaussy, Metz-France. Its high content of hemicelluloses (26 %), lignin (26 %) and cellulose (36 %) makes it a good source of polymers and renewable fuel. In the present study we have characterized the straw of MxG and optimized the process of delignification in a single step (1) by an ethanol organosolv treatment and in a two steps (2) including an autohydrolysis pretreatment with water / organosolv. The ethanol organosolv process permits a good separation of the three constituents of our biomass (lignin, cellulose and hemicelluloses). The two steps treatment process, involving an autohydrolysis with water (in the presence or absence of 2-naphthol) before the pretreatment organosolv has facilitated the later stage of delignification in destructurizing the lignin. An investigation of the physico-chemical properties was performed on the structure of the milled wood lignin and organosolv lignin of MxG extracted with different treatment severities. A way of valorization for the organosolv lignin has been proposed by their incorporation in the formulation of an adhesive for wood in which a non volatile and low toxic aldehyde (glyoxal) is used instead of formaldehyde. A formulation consisting in 100 % of natural resins (60 % tannins of mimosa and 40 % of glyoxalated lignin) was used for the production of particle board and gave promising results with internal bond strength of 0.41 MPa, higher than the value of the current European standard. Finally, a study was conducted on the antioxidant properties of organosolv lignin extracted at different severities. The results have shown a correlation between the antioxidant activity and the operating conditions of treatment organosolv, the average molecular weight, the polydispersity index and the phenolic hydroxyl groups of lignin

A large part of the world paper manufacturing consists of production of corrugated board components, kraftliner and fluting, that are used in many different types of corrugated boxes. Because these boxes are stored and transported, they are often subjected to changes in relative humidity. These changes together with mechanical loads will increase the deformation of the boxes compared to the case where the same loads are applied in a static environment. This enlarged creep due to the changes in relative humidity is called mechano-sorptive or accelerated creep. Mechano-sorptive creep forces producers to use high safety factors when designing boxes, and therefore, this is one of the key properties of kraftliner boards.   Different strategies to decrease mechano-sorptive creep, and to simultaneously gain more knowledge about the causes for this phenomenon in paper, are the aim of this work. Derivatised and underivatised black liquor lignins, a by-product produced in pulp mills in large quantities, have been used together with biomimetic methods, to modify the properties of kraftliner pulp. Furthermore, the properties of kraftliner pulp have been compared to other pulps in order to evaluate the influence of fibre morphological factors, such as fibre width and shape factor, on the mechano-sorptive creep. In addition the influence of the chemical composition of the kraftliner pulp has been evaluated both by means of treating a kraftliner pulp with chlorite and xylanase and by producing pulps with different chemical composition.   By using lignin and biomimetic methods, to create radical coupling reactions, it has been shown that it is possible to increase the wet strength of kraftliner pulp sheets. This method of treating the pulp showed, however, no significant effects on the mechano-sorptive creep. The addition of an apolar suberin-like lignin derivative, which has been shown to be possible to produce from natural resources, did show a positive effect on mechano-sorptive creep properties, but at the expense of stiffness properties in constant climate. Different pulps were compared with a kraftliner pulp and it was observed that the ratio between tensile stiffness and hygroexpansion can be used to estimate the mechano-sorptive creep properties. The hardwood kraft pulps investigated had lower hygroexpansion, probably due to more slender and straighter fibres, and higher tensile stiffness, probably due to lower lignin content. As the lignin content was varied by different methods in kraft pulps, it was observed that increased lignin content gives an increased hygroexpansion and decreased tensile stiffness as well as an increased mechano-sorptive creep. There were also indications of increased mechano-sorptive creep due to higher xylan content. / En stor del av världens papperstillverkning utgörs av produktion av wellpappkomponenter, kraftliner och fluting, som används i en uppsjö av olika wellpapplådor. När dessa lådor lagras och transporteras utsätts de ofta för förändringar i relativa luftfuktigheten. Dessa förändringar tillsammans med mekanisk belastning ökar lådornas deformation jämfört med om samma belastning skulle ha applicerats vid ett statiskt klimat. Denna förhöjda krypning på grund av förändringarna i relativ luftfuktighet kallas mekanosorptiv- eller accelererad krypning. Mekanosorptiv krypning tvingar producenterna att ha höga säkerhetsmarginaler vid dimensioneringar av lådor och är därför en av nyckelegenskaperna för kraftliner.   Olika strategier för att minska denna effekt, och på samma gång erövra mer kunskap om orsakerna till detta fenomen, har varit syftet med arbetet. Derivatiserade och oderivatiserade svartlutslignin, en biprodukt möjlig att få ut i stora kvantiteter från massabruk, har används tillsammans med biomimetriska metoder, för att modifiera kraftlinermassas egenskaper. Dessutom har kraftlinermassans egenskaper jämförts med andra massors egenskaper för att utvärdera inverkan av fibermorfologiska faktorer, såsom fiberbredd och fibreform på det mekanosorptiva krypet. Också inverkan av den kemiska sammansättningen av kraftliner massan har undersökts både genom behandling med klorit och xylanas och genom att producera massor med olika kemiska sammansättningar.   Genom att använda lignin och biomimetriska metoder för att skapa radikal-kopplingsreaktioner har det visats på möjligheten att öka våtstyrkan i massa-ark. Det här sättet att behandla massa visade dessvärre inga signifikanta effekter på det mekanosorptiva krypet. Tillsatts av ett apolärt suberin-liknande ligninderivat, som visats möjligt att producera ur naturliga råmaterial, visade en positiv effekt på det mekanosorptiva krypegenskaperna även om det var på bekostnad av styvheten vid konstant klimat. Olika massor jämfördes med en kraftlinermassa och det observerades att relationen mellan dragstyvhet och hygroexpansion kan användas för att uppskatta de mekanosorptiva krypegenskaperna. Lövvedssulfatmassorna som undersöktes hade lägre hygroexpansion, antagligen beroende på smalare och rakare fibrer, och högre dragstyvhet, troligen beroende på en lägre ligninhalt. När ligninhalten varierades i sulfatmassor med olika metoder observerades att ökad ligninhalt ger en ökad hygroexpansion och minskad dragstyvhet liksom en ökad mekanosorptiv krypning. Dessutom fanns indikationer på en ökad mekanosorptiv krypning till följd av högre xylaninnehåll. / QC 20100629

Vor dem Hintergrund des weltweit wachsenden Bedarfes an Bodenverbesserungsmitteln, durch die Humus-, Nährstoff- und Wassermangel auf Problemstandorten kompensiert werden sollen, war es das Ziel der vorliegenden Arbeit, Bodenwasser-speicher auf Basis der nachwachsenden Biopolymere Stärke und Lignin zu entwickeln. Durch Derivatisierung der Stärke wurde deren Hydrophilie deutlich gesteigert, was Voraussetzung für die Bildung von Hydrogelen war. Es konnte gezeigt werden, dass durch Vernetzung der wasserlöslichen Stärkederivate Carboxymethylstärke und Monostärkemonophosphat mit Di-/Tricarbonsäuren quellfähige Hydrogele erzeugt werden, deren Quellungsvermögen und rheologische Eigenschaften über die Wahl des Vernetzers und die Vernetzerstoffmenge gezielt eingestellt werden können. Die Modifizierung von Lignin wurde durch Oxidation mit Wasserstoffperoxid, z.T. in Kombination mit Fe(II)- bzw. Mn(II)-Chloriden realisiert. Dadurch wurde die Vernetzbarkeit von Lignin deutlich verbessert, was auf oxidativ bedingte Strukturänderungen des Lignins zurückzuführen war. Diese bestanden im Wesentlichen in der Spaltung und Oxidation der Lignin-Seitenkette sowie der Hydroxylierung der Seitenkette und aromatischer Strukturen. Die Vernetzung von Lignin mit Poly-(ethylenglycol)-diglycidylether ergab quellfähige Hydrogele, deren Wasseraufnahmevermögen und rheologische Materialfunktionen von der eingesetzten Vernetzerstoffmenge abhängig sind. Es konnte gezeigt werden, dass durch den Einsatz von Stärkephosphat- und Lignin-Hydrogelen das Wasserspeichervermögen erhöht und die Evaporationsraten eines entsprechend behandelten Sandbodens verringert werden. Im Wachstumsversuch wurden die Frischmasseerträge von Gelbsenf (Sinapis alba) durch Behandlung eines Sandbodens mit Hydrogelen gesteigert. / Soil degradation leading to a lack of humus, nutrients and water especially on exploited sites causes the worldwide need in soil amendments. Aim of the work was the development of hydrogels from renewable biopolymers starch and lignin improving water retention especially in degraded soils. A significant increase of hydrophilic properties of starch was obtained by chemical modification with the objective of forming starch based hydrogels. Swellable hydrogels were formed by cross-linking of water soluble starch derivatives like carboxymethyl starch and monostarch monophosphates with di- and tricarboxylic acids. Swelling capacity and rheological properties of the starch gels were selective adjusted by variation of cross linking agent and whose amounts. Modification of lignin was realized by oxidation with hydrogen peroxide partly in combination with ferrous and manganese chlorides, respectively. In consequence of oxidative structural changes which were cleavage and oxidation of side chain as well as aliphatic and aromatic hydroxylation, gelation of lignin was improved significant. Lignin hydrogels with different swelling capacities and rheological functions were formed by cross-linking lignin with different amounts of poly (ethylene glycol) diglycidyl ether. Application of hydrogels based on starch and lignin causes increased water storing capacity/field capacity and decreased evaporation of a sandy soil as well as an increased biomass yield of yellow mustard (Sinapis alba).

No description available.

Biomass has been used as a fuel since ancient times. In recent decades the use has increased and the technology has developed considerably in large parts of the world. In Sub Saharan Africa, traditionally used biomass, such as wood or charcoal, is still the main source of energy in households. Zambia consumes charcoal corresponding to 6 089 000 tonnes/year. The use of biomass is very ineffective and with increasing population and energy requirements, this is placing Zambia on the top ten list of highest deforestation rates in the world.  Emerging Cooking Solutions Zambia Ltd. [ECS], started in 2012 with a vision to establish a pellet production in Africa. They provide modern cooking stoves and fuel pellets to counteract the unsustainable use of biomass and the health risk with traditional fuels. ECS aims to expand their production and are now striving to find a biomass that can increase hardness of pellets. The purpose of this work is to increase knowledge of the ability of raw materials to be pelletized, to support ECS expansion in a sustainable manner.  In this report fourteen different biomasses was evaluated at three different moisture content, 5%, 7,5% and 10%. Peanut shell, Pigeon Pea, Pine and Sicklebush was assumed to be able to be used as a base material. Remaining biomasses as additive; Bamboo, Cassava peel, Cassava stem, Eucalyptus, Gliricidia, Peanut shell, Lantana, Miombo seed capsules, Olive tree and Tephrosia. Pellet production was performed in a single pellet press located at the department of environmental and energy system at Karlstad University, Karlstad. Compression energy, friction energy, hardness and moisture uptake was some of the operating characteriztics and properties that were evaluated. Additionally, four blends were pelletized with the aim to increased hardness.  Pigeon Pea resulted in hardest pellets of the base materials, it managed a radial pressure of 46.3 kg, Pine resulted in low hardness, 17.7 kg. For the additives, the following materials were hardest as pellets; Tephrosia, 70.0 kg, Gliricidia 58.7 kg, Cassava peel 48.6 kg och Miombo seed capsules, 48.3 kg. Pine was the material that required relatively more energy pelletizing, 183.0 J. Lowest energy, Cassava stem, 49,1 J.  All blends resulted in higher hardness of pellets. Most advantageous were Cassava peel and Tephrosia. Cassava peel in Pigeon Pea increased hardness even at 10% and reduced energy requirements. Pigeon Pea with 50% Tephrosia increased hardness with 21.1 kg to 67.4 kg, slightly increasing energy requirements. Though logistic chain for Cassava peel was evaluated higher than Tephrosia.  For ECS to expand their production they are recommended, accordingly to the results in this study, to use Pigeon Pea at about 6% moisture content, as a base material. In order to increase hardness of pellets, they should primarily use Tephrosia, about 7% and Cassava peel at approximately 8% moisture content as an additive. / Biomassa har använts som bränsle sedan urminnes tider. Användningen har ökat och olika tekniker för nyttjande har utvecklats avsevärt i stora delar av världen de senaste decennierna. I Afrika söder om Sahara utgör traditionellt använd biomassa, såsom ved eller träkol fortfarande den huvudsakliga källan till energi i hemmet. Zambia konsumerar träkol motsvarande 6 089 000 ton ved varje år. Användningen av biomassan är mycket ineffektiv och med en ökande befolkning och energibehov sätter detta Zambia på topp tio listan med högsta avskogningshastigheter i världen.  Emerging Cooking Solutions Zambia Ltd [ECS], startade 2012 med visionen att etablera en pelletsproduktion i Afrika. De tillhandahåller moderna pelletsbrännare och producerar bränslepellets för att motverka problemet med den ohållbara användningen av biomassa och hälsorisker i samband med detta. ECS har som mål att öka sin produktion och eftersträvar nu främst att hitta en spetsråvara som kan öka hårdheten på pellets. Syftet med denna rapport är att öka kunskapen om råvarors möjlighet att pelleteras för att bidra till att Emerging Cooking Solutions verksamhet ska kunna expandera på ett hållbart sätt.  I denna rapport utvärderades fjorton olika biomassor vid tre olika målfukthalter 5%, 7,5% och 10%. Jordnötsskal, Pigeon Pea, Pine och Sicklebush ansågs kunna användas som basdrift, resterande biomassor som spetsråvaror, Bambu, Cassavaskal, Cassavastam, Eucalyptus, Gliricidia, Lantana, Miombo, Olivträd och Tephrosia. Pelletsproduktion gjordes i en enpetare vid Karlstads universitet, avdelningen för miljö-, och energisystem. Kompressions- och friktionsenergi samt hårdhet och fuktupptag är några av de variabler som testades, dessutom pelleterades fyra blandningar av olika biomassor med syfte att öka hårdheten på pellets.  De basmaterial som resulterade i hårdast pellets var Pigeon Pea som klarade ett radiellt tryck på 46,3 kg, Pine medförde låg hårdhet, 17,7 kg. Av spetsråvarorna medförde följande högsta hårdhet på pellets, Tephrosia, 70 kg, Gliricidia 58,7 kg, Cassavaskal 48,6 kg och Miombo frökapslar, 48,3 kg. Vid kompressionsstudierna visade sig Pine kräva relativt hög energi vid komprimering, 183,0 J. Lägst Cassavastam 49,1 J.  Samtliga blandningar med Tephrosia, Cassavaskal eller Gliricidia som spetsråvaror medförde hårdare pellets. Mest fördelaktigt som spetsråvara var Tephrosia och Cassavaskal. Cassavaskal ökade hårdheten redan vid 10% inblandning i Pigeon Pea och minskade samtidigt energibehovet. Vid inblandning av 50% Tephrosia i Pigeon Pea ökade hårdheten mest av samtliga blandningar med 21,1 kg till 67,4kg. Logistikkedjan bedömdes dock bättre för Cassavaskal än för Tephrosia.  ECS skulle enligt resultaten i denna studie kunna använda sig av Pigeon Pea vid cirka 6% fukthalt för att bredda sin råvarubas. För att öka hårdheten på pellets bör de i första hand använda sig av Tephrosia cirka 7% och Cassavaskal cirka 8% fukthalt som spetsråvara.

L'objectif de cette étude est la diminution du pouvoir de combinaison du dioxyde de soufre des vins blancs liquoreux. La méthode retenue passe par l'élimination du vin de dérivés carbonylés naturellement présents et responsables de la formation de combinaisons bisulfitiques.Les dérivés carbonylés responsables de la plus grande partie du piégeage du dioxyde de soufre sont l'éthanal, l'acide pyruvique et l'acide 2-oxoglutarique. L'extraction de ces composés doit s'effectuer sans dénaturer les qualités organoleptiques du vin et sans générer l'apparition de nouvelles molécules dans le vin. Pour cela, la méthode retenue a été l'extraction liquide-solide : il s’agit de mettre en présence deux réactifs dont l’un l’agent d’extraction est fixé sur un support insoluble. Notre objectif est d’étudier la possibilité de substituer les polymères d’origine industrielle utilisés jusqu’à présent par des supports d’origine naturelle préparés à partir d’un constituant du bois : la lignine. Le recours à des supports d’origine naturelle, dérivé du bois, présente le double intérêt de permettre un meilleur contrôle des matériaux introduits dans le vin à traiter et de rendre les contaminations éventuelles provenant du traitement à priori, plus admissibles, étant constituées de composés déjà présents dans le bois de tonnellerie. / The objective of this study is the reduction of the power of sweet white wines sulfur dioxide combination. The method used relies on the extraction of carbonyl compounds from wine; these are naturally present and responsible for the formation of bisulfite combinations.The carbonyl compounds responsible for most of the trapping of sulfur dioxide are acetaldehyde, pyruvic acid and the 2-oxoglutaric. The extraction of these compounds should be done without altering the organoleptic qualities of wine and without creating the appearance of new molecules in wine. Therefore, the method we used was the liquid-solid extraction: bringing together two reactants, one of which -the extracting agent- is attached to an insoluble support.Our goal is to study the possibility of substituting the industrial polymers, used so far, by natural origin supports, prepared from a wood constituent: the lignin.The use of natural origin materials, deriving from wood, has the double advantage of allowing a better control of materials, introduced in the wine process, and making more acceptable the possible contaminations broad about by the a priori treatment, as they are compounds already present in the wood cooperage.

Orientadores: João Alexandre F. da Rocha Pereira, Cesar Augusto M. de Abreu / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-07-28T21:49:09Z (GMT). No. of bitstreams: 1 Sales_FernandoGazelli_D.pdf: 3615056 bytes, checksum: 37a35bf7a6015215ae5ab7c8f1aa4bb5 (MD5) Previous issue date: 2001 / Resumo: Os materiais lignocelulósicos, representando a maior reserva natural renovável da natureza, encontram-se armazenados nas plantas sob a forma de celulose, hemicelulose, lignina e extrativos, com a lignina correspondendo cerca de 30% deste total. As rotas de beneficiamento da lignina, com destaque para os processos oxidativos, visando a produção de vanilina, principalmente, utilizam na grande maioria processos bifásicos, alguns utilizando catalisadores solúveis na fase líquida, operando no entanto, com baixos rendimentos. No presente trabalho desenvolveu-se um processo de oxidação úmida catalítica (CWAO) da lignina para a produção seletiva de aldeídos aromáticos, com ênfase na vanilina, siringaldeído e p-hidroxibenzaldeído, aplicando um catalisador de paládio suportado em y-alumina. Prevendo-se a avaliação do processo catalítico foram conduzidas experiências em reator auto clave mecanicamente agitado, operando em batelada alimentada com relação à fase gasosa. Operou-se entre 373K e 413K, a uma pressão total de 20bar, representando uma pressão parcial de oxigênio entre 2bar e 10bar. A lignina com concentração de 60gIL foi solubilizada em meio alcalino de NaOH 2N. Utilizou-se um catalisador de Pd (2,85%pp.), em y-alumina, com granulometria entre 90_m e 200_m, aplicando-se concentrações de 3%pp. a 5%pp. em relação ao volume reacional. As reações de degradação da lignina e de formação de aldeídos aromáticos foram descritas por um modelo cinético quantificado por um sistema de reações complexas do tipo série-paralelo, com etapas de pseudo-primeira ordem. A presença do catalisador resultou em níveis de rendimento e seletividade em aldeídos, muito superiores quando comparados com o processo não catalítico, representando uma redução de cerca de 50% na energia de ativação para a degradação da lignina. Os níveis de conversão da lignina em aldeídos foram de 6% a 393K, 12% a 393K e 18% a 423K, para uma pressão parcial de oxigênio de 5bar e carga de catalisador de 4%pp. Com a finalidade de produzir aldeídos aromáticos em regime contínuo, um reator de leito fluidizado trifásico contínuo foi projetado e construído, em escala mini-piloto. O sistema foi avaliado hidrodinamicamente, em testes pré-operacionais, através de análise experimental utilizada aplicou a distribuição dos tempos de residência (DTR) na fase gasosa, utilizando o gás metano como traçador. A estimação dos dois parâmetros recorreu à confrontação das previsões obtidas via função de transferência do sistema, com os resultados provenientes dos experimentos dinâmicos, adotando-se como critério a minimização de uma função objetivo através de uma subrotina de busca seqüencial. Os resultados obtidos, de 2,2% a 9,3% para a retenção gasosa, e 38,0 a 54,4 para o número de Peclet da fase gasosa, estão compatíveis com os valores publicados na literatura para reatores de dimensões semelhantes operando nas mesmas condições. A produção de aldeídos aromáticos em regime contínuo, no reator de leito fluidizado trifásico, utilizou como agente oxidante o ar atmosférico a uma pressão de 4 bar. As influências dos parâmetros operacionais foram avaliadas dentro das ITonteiras práticas de operação, isto é, vazões da fase líquida de 5,OL/h e 10LIh, temperaturas de 393K e 413K. A vazão da fase gasosa foi fixada em 1000 NL/h com uma carga de catalisador de 4%pp e granulometria de 400llm - 5001lID. A lignina foi dissolvida em uma solução alcalina de hidróxido de sódio 2N a uma concentração de 30g/L. O melhor rendimento em aldeídos aromáticos foi de 12% em relação a concentração inicial de lignina, com o reator operando a 393K e vazão da fase líquida de 5L/h / Abstract: The lignocellulosic material, representing the largest natural renewable resource, occurring in the plants under the cellulose form, hemicellulose, lignin and extractive, with the lignina corresponding about 30% of this total one. The routes of lignin chemical processing, with prominence for the oxidations processes, with the objective of vanilin production, use in the great majority two-phase processes, some using soluble catalysts in the liquid phase, operating however, with low efficiency. In the present work a process of catalytic wet air oxidation (CW AO) was developed with the objective of selective production of aromatic aldehydes, with emphasis in the vanilina, siringaldeído and p-hidroxibenzaldeído, ITom lignin, applying a palladium catalyst supported in y-alumina. Intending the evaluation of the catalytic process, experiences were carried out in a mechanically stirred high pressure autoclave reactor, in semi-batch way, in relation to the gaseous phase. It was operated in temperatures ITom 373K to 413K, at a total pressure of 20bar, representing a partia! pressure of oxygen ITom 2bar to 10bar. The lignin concentration of60gIL was in an aIkaline medium ofNaOH 2N. A palladium catalyst was used (2,85%pp.), in y-alumina, with granulometry ITom 90mm to 200mm, being applied concentrations ITom 3%pp. to 5%pp. in relation to the reactional volume. The reactions of lignin degradation and aromatic aldehydes production were described by a kinetics model quantified by a system of complex reactions of the series-parallel type, with stages of pseudo-first order. The presence of the catalyst resulted in high levels of seletivities in aldehydes, further than as compared with the non-catalytic process, representing a reduction about 50% in the activation energy for the lignin degradation. The levels of conversion ofthe lignin in aldehydes were of6% at 393K, 12% at 393K and 18% at 423K, for a partial pressure of oxygen of 5bar and catalyst loading of 4%pp. With the purpose of producing aromatic aldehydes in continuous regime way, a three-phase fluidized bed reactor was designed and built, in mini-pilot scale. The system was evaluated hydrodynamically, in pre-operational tests, through applying dynamic analysis for the gaseous phase. The hydrodynamic analysis of the system was accomplished through the values of the gaseous retention (8G) and of the ofaxial Peclet number (PeG). The experimental technique applied the residence time distribution (RTD) in the gaseous phase, using the methane gas as tracer. The estimation ofthe two parameters felI back upon the conftontation ofthe prevision obtained through transfer function ofthe system, with the results uom the dynamic experiments, being adopted as approach the minimization of a objective function through a subroutine of sequencial search. The obtained results, uom 2,2% to 9,3% for the gaseous retention, and 38,0 to 54,4 for the number of Peclet of the gaseous phase, are compatible with the values published in the literature for reactors operating in the same conditions. The aromatic aldehydes production in a continuous three-phase fluidized bed reactor, used as oxidizing agent the atmospheric air in apressure of 4 bar. The influences of the operational parameters were evaluated in the practical ranges of operation, that is, liquid phase flow rate of 5,OL/h and lOL_ temperatures of 393K and 413K. The gaseous phase flow rate was 1000 NL/h with a catalyst loading of 3%pp and granulometry of 400 j.1m 500j.1m The lignin was in an aIkaline medium of NaOH 2N, in a concentration of 30g/L. The best yield in aromatic aldehydes reached 12% in relation to lignin initial concentration, as the reactor was operating at 393K and liquid flow rate of5LIh / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química

Carbon fiber is a lightweight, versatile material with many current and potential applications. To be able to expand the market for carbon fiber composites in other areas than special applications the production costs must be reduced. One way of accomplishing this could be to use a less expensive raw material where lignin is a good example as it can be provided at lower cost, is renewable and abundantly available compared to commercially used raw materials today. So far, the mechanical properties of lignin-based carbon fibers are inferior relative to commercial carbon fibers. For lignin-based carbon fibers to enter the commercial market more research is necessary to gain knowledge of the conversion of lignin to carbon fiber. The LightFibre project investigates the possibilities to produce carbon fibers based on a mixture of softwood kraft lignin and cellulose. The kraft lignin is isolated from black liquor in the kraft/sulfate process with the LignoBoost process. This master thesis project was conducted within in the LightFibre project and evaluated whether metal ions generally present in kraft lignin had an influence on the final carbon fiber quality in terms of mechanical properties and morphology. The mechanical properties were determined with tensile testing, the morphology by scanning electron microscopy (SEM) and the relative abundance of studied elements with electron dispersive spectroscopy (EDS). The influence of the chosen metal ions was tested by impregnation of dry-jet wet spun prefibers based on 70 wt.% softwood kraft lignin and 30 wt.% dissolving pulp cellulose. The fibers were impregnated in room temperature with solutions containing Na2SO4, K2SO4, MgSO4, FeSO4 and Al2(SO4)3 salts where the cations were the focus in these trials. The concentrations used for impregnation were 0.2 and 1M of the cations. The obtained mechanical properties of the carbon fibers of the samples impregnated with different metal ions did not deviate significantly from the reference which had a tensile strength of 870 MPa and tensile modulus of 68 GPa. The analysis of morphology with SEM showed no defects or damage of any of the fibers. Therefore, it was concluded that the impregnated metal ions: K+, Na+, Al3+, Mg2+ and Fe2+ at the obtained levels in the fibers cause no effects on the fibers during the stabilization and carbonization that affects the mechanical performance of final carbon fiber.  The amount of potassium in one of the samples was estimated to 0.1 wt.%. From the results of this study it may be suggested that the general recommendation of <0.1 wt.% ash in lignin can be exceeded, for dry-jet wet-spun kraft lignin/cellulose-based carbon fibers.

La liquéfaction de biomasse en conditions hydrothermales est un procédé intéressant pour les ressources contenant naturellement une part importante d'eau. Ce type de procédé a lieu dans des conditions de hautes température et pression (250-370 °C, 50-250 bar). Dans ces circonstances, différentes propriétés physico-chimiques de l'eau sont modifiées permettant notamment de faciliter les réactions de dégradation des polymères structurant la biomasse. Ce travail de thèse a eu pour but l'étude de la réactivité en conditions hydrothermales de différentes molécules modèles représentant divers segments d'une biomasse concrète. L'effet de l'ajout de catalyseurs hétérogènes dans le milieu réactionnel a été étudié. Ces catalyseurs ont été caractérisés avant et après les avoir soumis à des conditions hydrothermales. Le catalyseur Pt/C synthétisé présentant des résultats prometteurs, différentes études cinétiques ont été menées sur les molécules modèles ciblées en présence de ce catalyseur / Hydrothermal liquefaction of biomass is a promising process for resources with high water content. This type of process takes place under high temperature and pressure conditions (250-370 °C, 50-250 bar). Under these circumstances, various water physicochemical properties are modified and enable to facilitate degradation reactions of polymers that structure biomass. The aim of this phD work is to investigate the reactivity of biomass model compounds (representative of diverse real biomass segments) in hydrothermal media. The effect of the addition of heterogeneous catalysts in reaction conditions has been studied. These catalysts have previously been characterized before and after an aging in hydrothermal conditions. Synthesized Pt/C catalyst presents promising results and thus various kinetic studies have been conducted with targeted model compounds in the presence of Pt/C