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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
431

Identifying Adaptations that Promote Softwood Utilization by the White-rot Basidiomycete Fungus, Phanerochaete carnosa

MacDonald, Jacqueline 17 December 2012 (has links)
Softwood is the predominant form of land plant biomass in the Northern hemisphere, and is among the most recalcitrant biomass resources to bioprocess technologies. The white rot fungus Phanerochaete carnosa has been isolated almost exclusively from softwoods, while most other known white-rot species, including Phanerochaete chrysosporium, were mainly isolated from hardwoods. Accordingly, it is anticipated that P. carnosa encodes a distinct set of enzymes and proteins that promote softwood decomposition. To elucidate the genetic basis of softwood bioconversion by P. carnosa, its genome was sequenced and transcriptomes were evaluated after growth on wood compared to liquid medium. Results indicate that P. carnosa differs from P. chrysosporium in the number and expression levels of genes that encode lignin peroxidase (LiP) and manganese peroxidase (MnP), two enzymes that modify lignin present in wood. P. carnosa has more genes for MnP with higher expression levels than LiP, while the reverse has been observed for P. chrysosporium. The abundances of transcripts predicted to encode lignocellulose-modifying enzymes were then measured over the course of P. carnosa cultivation on four wood species. Profiles were consistent with decay of lignin before carbohydrates. Transcripts encoding MnP were highly abundant, and those encoding MnP and LiP featured significant substrate-dependent response. Since differences in modes of lignin degradation catalyzed by MnP and LiP could affect the ability of each to degrade lignin from different types of wood, their activity on various hardwoods and softwoods were tested. Results suggest that MnP degrades softwood lignin more effectively than hardwood lignin, consistent with high levels of this enzyme in P. carnosa.
432

Otimização do método lignina brometo de acetila na determinação do teor de lignina em plantas forrageiras e comparação com os métodos lignina detergente ácido e lignina Klason / Improving the acetyl bromide lignin method in determining lignin content in forages and comparison with the methods acid detergent lignin and Klason lignin

Marcos Felipe Zuñiga Santamaria 15 February 2016 (has links)
Técnicas analíticas empregadas para a quantificação do teor de lignina em plantas forrageiras, atualmente em uso, são questionáveis quanto às suas acurácias. O método lignina detergente ácido (LDA), que é um dos métodos mais utilizado em Ciência Animal e Agronomia, apresenta algumas falhas, particularmente devido à parcial solubilização da lignina durante a preparação da fibra em detergente ácido (FDA). A lignina Klason (LK), outro método muito usado, apresenta o inconveniente de mensurar a proteína da parede celular como sendo lignina. Em ambos os procedimentos recomenda-se também mensurar cinzas nos resíduos de lignina. A quantificação da concentração de lignina pelo método espectrofotométrico lignina brometo de acetila (LBA) vem ganhando interesse de pesquisadores no Brasil e no exterior. Nesta metodologia, a lignina da planta contida na preparação parede celular (PC) é solubilizada numa solução a 25% de brometo de acetila em ácido acético e a absorbância mensurada é com luz UV a 280 nm. O valor da absorbância é inserido numa equação de regressão e a concentração de lignina é obtida. Para que esta técnica analítica seja mais aceita pelos pesquisadores, ela deve ser, obviamente, convincente e atrativa. O presente trabalho analisou alguns parâmetros relacionados à LBA em 7 gramíneas e 6 leguminosas, em dois estádios de maturidade. Dentre as diferentes temperaturas de pré-secagem, os resultados indicaram que os procedimentos de 55°C com ventilação e liofilização podem ser utilizados com a mesma eficácia. As temperaturas de 55°C sem ventilação e 80°C sem ventilação não são recomendadas, pois aumentaram os valores de FDA e LDA, possivelmente devido ao surgimento de artefatos de técnica como os compostos de Maillard. No método LBA os valores menores das amostras de leguminosas chamaram a atenção e colocaram em questão se a lignina destas plantas seria menos solúvel no reagente brometo de acetila. Dentre algumas alterações na metodologia da técnica LBA, a utilização do moinho de bolas (para diminuir o tamanho particular) nas amostras de PC não mostrou efeito; a hipótese era melhorar a solubilização da lignina usando partículas menores. O uso de um ultrasonicador, que aumenta a vibração das moléculas e assim, facilitaria a solubilização da lignina no reagente brometo de acetila, melhorou a solubilização da lignina em cerca de 10%, tanto nas gramíneas como nas leguminosas. Foi acoplado um ensaio biológico como referência, a degradabilidade in vitro da matéria seca (DIVMS); e como a lignina está intimamente associada à estrutura fibrosa da parede celular, também foi feito um ensaio de degradabilidade in vitro da fibra em detergente neutro (DIVFDN). Os resultados confirmaram o efeito da maturidade, reduzindo a degradabilidade nas plantas mais maduras, e que o teor de lignina de leguminosas é realmente inferior ao de gramíneas. Os resultados de degradabilidade apresentaram coeficientes de correlação mais elevados com o método LBA, quando foi empregada a técnica do ultrasom; o método LK mostrou os menores coeficientes. Também testou-se, com sucesso, a utilização da FDN, como preparação fibrosa, ao invés de PC. A razão é simples: enquanto que a FDN é amplamente conhecida, a preparação PC não o é. Inquestionável que esta manobra facilitará substancialmente a divulgação desse método, tornando-a mais aceitável pela comunidade científica / Analytical techniques employed to quantify lignin content in forages, currently in use, are questionable as to their accuracies. The method acid detergent lignin (ADL), which is one of the most used method in Animal Science and Agronomy, has some flaws, due to the partial lignin solubilization during the preparation of acid detergent fiber (ADF). The Klason lignin method (KL), another analytical procedure commonly used, has the drawback of measuring the cell wall protein as lignin. In both procedures also are recommended to measure ash content in the lignin residues. Quantification of lignin concentration by the spectrophotometric acetyl bromide lignin method (ABL) has been gaining interest from researchers in Brazil and abroad. In this methodology, the lignin contained in the plant cell wall preparation (CW) is solubilized in a 25% acetyl bromide in acetic acid solution and the absorbance is measured with UV light at 280 nm. The absorbance value is inserted in a regression equation and the concentration of lignin is obtained. For this analytical technique be better accepted by researchers, it must be, obviously, convincing and attractive. This study analyzed some LBA-related parameters in 7 grasses and 6 legumes in two stages of maturity. Among the different temperatures of pre-drying, the results indicated that the procedures at 55°C with ventilation and lyophilization can be used just as effectively. Temperatures of 55 and 80 both without ventilation are not recommended because they increased ADF and ADL values, possibly due to the emergence of technical artifacts such as the compounds of Maillard. The ABL method yielded lower values for legume samples which called into question if the lignin of these plants is less soluble in the acetyl bromide reagent. Among some changes studied in the ABL technique it was the utilization of ball milling in the PC samples, which showed no effect; the hypothesis was to reduce the particle size and thus improve the solubilization of lignin. The use of an ultrasonicator, which increases the vibration of molecules and possibly allowing better solubilization of lignin in the acetyl bromide reagent improved lignin solubilization by about 10%, both in grasses. As a reference, an in vitro dry matter degradability (IVDMD) was conducted. Because lignin is closely linked to the fibrous structure of the cell wall, an in vitro neutral detergent fiber degradability (IVNDFD) test of. Results confirmed the effect of maturity, reducing degradability as the plants matured, and that concentration of lignin is lower in legumes than in grasses. The degradability results showed higher correlation coefficients with the ABL method when the ultrasonicator was used; the KL method showed the lowest coefficients. We also tested, successfully, the use of NDF as a fiber preparation, instead of crude CW. While NDF is widely known, CW preparation is not. This maneuver will substantially facilitate the dissemination of this method, making it more acceptable to the scientific community
433

Entwicklung ramanspektroskopischer Messmethoden zur Untersuchung lignocelluloser Pflanzenmaterialien

Feldner, Alexander 20 July 2017 (has links) (PDF)
Landlebende Pflanzen weisen differenzierte Gewebetypen auf, die neben der Aufrechterhaltung physiologischer Stoffwechselvorgänge äußeren mechanischen Belastungen standhalten müssen. Durch zweckmäßige Verteilung von Festigkeitsgeweben über den Sprossquerschnitt erlangen Pflanzen die notwendigen Versteifungen und Stabilitäten. Zur ortsaufgelösten Darstellung der unterschiedlichen Pflanzengewebe wird auf die Methode der Ramanspektroskopie zurückgegriffen. Dazu werden valide ramanspektroskopische Methoden entwickelt, die die Bestimmung der Cellulosekristallinität sowie die Quantifizierung des Lignins und der Hemicellulosen zum Ziel haben. Am Beispiel eines Pflanzenquerschnittes des Gemeinen Flachs Linum usitassimum werden die spektroskopischen Methoden angewandt und die Verteilung der unterschiedlichen Gewebetypen aufgezeigt und diskutiert.
434

Introduction of a Sustainable Alternative for Bitumen : Case study of lignin-based asphalt for the Swedish market / Introduktion av ett hållbart alternativ till Bitumen : Fallstudie av ligninbaserad asfalt för den svenska marknaden

Hashmi, Shkar, Jabary, Ahmed January 2020 (has links)
For some time, sustainability has been the major principle of development across the globe, and all aspects of society are somehow affected by the concept. Companies are faced with stricter regulations and are forced to look for solutions to reduce their environmental impact. A key challenge in society is reducing dependence on fossil fuels in favour of renewable materials. The asphalt industry is a sector that has a substantial environmental impact where one of the main components of asphalt is the binder, bitumen, which is produced from petroleum. One prominent alternative with notable binding capabilities, which resembles the chemical structure of bitumen, is lignin. The work on substituting bitumen with lignin has come the furthest in the Netherlands, where they have been able to substitute 50 % of bitumen with lignin. Several demonstration roads have also been laid, and extensive research on the concept is ongoing. This study was conducted with the Research Institutes of Sweden (RISE) and the LignoCity initiative. The study aims to examine the current technical- and business market situation of lignin-based asphalt, and through this, present a roadmap for the introduction of lignin-based asphalt to the Swedish market. The research method is qualitative in the form of a case study with semi-structured interviews. The gathered data was analysed and presented through the processes of thematic analysis, and a systematic combining approach was utilized throughout the study. The study highlights both obstacles and potentials for the introduction of lignin-based asphalt to the Swedish market. The main obstacles were found to be the need for long-term testing and evaluation in Swedish climate and conditions. Passive manufacturers hesitant to invest in the concept, and buyers restrained by regulations also act as significant barriers. The findings suggest that projects and collaborations between actors on the market are necessary to encourage new developments. Procurement procedures and tax-policies should also be amended to favour sustainable solutions. Benefits such as carbon sequestration, noise reduction, and lower rolling resistance should be emphasized.
435

3D-printing med träEn möjlighet för framtiden? / Wood-based 3D printing- A future possibility?

Touma, Rikard, Pettersson, Nathalie January 2021 (has links)
3D-skrivare har många användningsområden och de har blivit vanliga i många industrier.Idag talas det om att denna teknik kan vara en möjlig väg till mer hållbart byggande.Tekniken anses lovande inom byggproduktion bland annat för att det visat sig att den kanreducera materialspillet och ge kortare byggtider. Till viss del används tekniken redan förbyggnadstillverkning, men då främst med betong.Målet med arbetet är att beskriva nuvarande kunskap rörande 3D-printing medträbaserad massa, samt att undersöka möjligheten till att använda en träbaserad massabestående av sågspån, vatten och lignin vid 3D-printing.För att kunna nå målet användes en kombination av litteratursökning och laborativaexperiment. Litteratursökningen användes både för att undersöka tidigare genomförda studiergällande träbaserade material i samband med 3D-printing, samt som inspiration för deingredienser och proportioner som används i de laborativa experimenten.Enbart studier om träbaserad 3D-printing studerades. De testobjekt som togs fram i delaborativa experimenten utvärderades i hållfasthet, dimensionsstabilitet och vidhäftning.Resultaten av det laborativa arbetet tyder på att det framtagna materialet går att extrudera,men att det har låg draghållfasthet. Lagren bands samman bra för samtliga tester, medantryckhållfastheten gav varierande resultat. Högst tryckhållfasthet gavs av den blandning somhade högst andel lignin, samt torkades under längst tid.Slutsatsen är att materialet kan vara till nytta, men att rätt användningsområde börbestämmas, då materialet inte tål alltför stora laster. / 3D printers have many uses and they have become common in many industries. Today, thistechnology is seen as a possible route to more sustainable construction. The technology isconsidered promising in construction engineering, among other things because it has beenshown that it can reduce material waste and provide shorter production times. To someextent, the technology is already being used for building construction, but then mainly withconcrete.The aim of this study is to describe current knowledge regarding 3D printing with woodbasedpulp and to investigate the possibility of using a wood-based pulp consisting ofsawdust, water and lignin for 3D printing.In order to reach the goal, a combination of literature search and laboratory experiments wasused. The literature search was used both to investigate previously conducted studiesregarding wood-pulp based materials in 3D printing and as inspiration for the ingredients andproportions used in the laboratory experiments.Only studies on wood-based 3D printing were studied. The test objects produced in thelaboratory experiments were evaluated in strength, dimensional stability and adhesion. Theresults of the laboratory work indicate that the produced material can be extruded, but that ithas low tensile strength. The layers bonded well for all tests, while the compressive strengthresults varied. The highest compressive strength was given by the mixture with the highestproportion of lignin and the longest drying time.The conclusion is that the material might be useful, but that the correct area of use should bedetermined, as the material cannot withstand excessive loads.Keywords:
436

Uklanjanje teških metala iz vode piljevinom drveta, celulozom i lignitom / HEAVY METALS REMOVAL FROM WATER BY WOOD SAWDUST, PULP AND LIGNIN

Šćiban Marina 14 May 2002 (has links)
<p><strong>Apstrakt je obrađen tehnologijama za optičko prepoznavanje teksta (OCR).</strong></p><p>Istraživana je mogućnost primene piljevine različitih vrsta drveta, tehničke celuloze i Kraft lignina kao adsorbenata različitih te&scaron;kih metala iz vode. Za adsorpciju te&scaron;kih metala koji su u vodi prisutni u vidu katjona, kao najbolji adsorbenti su se pokazale piljevine drveta hrasta i bagrema i Kraft lignin. Za adsorpciju hromatnih anjona najbolje su se pokazali Kraft lignin i piljevina drveta jele. Kapacitet adsorpcije piljevine drveta se može pobolj&scaron;ati prethodnim tretiranjem piljevine rastvorom natrijum hidroksida. Efikasnost adsorpcije te&scaron;kih metala iz vode je bolja: kada se primenjuju sitnije čestice piljevine, kada se radi sa većom količinom piljevine i/ili dvostepeno, na povi&scaron;enoj temperaturi. Utvrđen je optimalni pH za adsorpciju pojedinih te&scaron;kih metala, optimalno vreme kontakta adsorbenta i vode, uticaj prisustva različitih te&scaron;kih i lakih metala i anjona na efikasnost adsorpcije te&scaron;kih metala. Adsorbovani te&scaron;ki metali se mogu desorbovati sa piljevine drveta rastvorima različitih mineralnih kiselina. Piljevina drveta se može primeniti u vi&scaron;e ciklusa adsorpcije-desorpcije, uz ne&scaron;to smanjeni kapacitet adsorpcije. Ispitivani adsorbenti se mogu primeniti i u dinamičkim uslovima adsorpcije u koloni.</p> / <p><strong>Abstract was processed by technology for Optical character recognition (OCR).</strong></p><p>The possibility of adsorption of different heavy metals from water by sawdust of different species of wood, pulp, and Kraft lignin has been investigated. Oak and black locust sawdust, and Kraft lignin were shown to be the most efficient adsorbents for heavy metals in cationic form. Kraft lignin and fir sawdust were shown to be the most efficient adsorbents for chromium anions. Previous treatment of wood sawdust by sodium hydroxide solution can increase its adsorption capacity. Better adsorption efficiency was accomplished: when smaller parts of sawdust were used, when a large amount of sawdust was used and/or two stage process was applicated, and adsorption process was done on higher temperature. There were established: optimum initial pH value for different heavy metals, optimum adsorbent - water contact time, and degree of influence of other different heavy and lite metals, and anions on adsorption efficiency. Adsorbed heavy metals can be desorbed from vvood sawdust with solutions of different mineral acids. Sawdust can be applied in several cycles of adsorption - desorption, with some decrease of adsorption capacity. Investigated adsorbents can be also used in dynamic conditions of adsorption in column.</p>
437

Untersuchungen zur Hydrogenolyse von Lignin in Zinkchlorid/Kaliumchlorid Salzschmelzen unter Berücksichtigung struktureller Merkmale

Appelt, Jörn 19 April 2013 (has links)
In Hinblick auf den stetig steigenden Bedarf der chemischen Industrie an Grundstoffchemikalien und der teilweise unsicheren Versorgung mit Erdöl und Erdgas ist es notwendig alternative Rohstoffe und Verwertungspfade für die Bereitstellung von Basischemikalien zu finden. Ziel der vorliegenden Arbeit war die Untersuchung der Hydrogenolyse von Lignin in niedermolekulare Produkte unter Verwendung geeigneter Salzschmelzen. Es konnte gezeigt werden, dass Lignin in Zinkchlorid/Kaliumchloridschmelzen in niedermolekulare Produkte abgebaut werden kann. Hierbei erwiesen sich der Einsatz eines entsprechenden Eutektikums und einer Alternativschmelze mit niedrigem Schmelzpunkt als hilfreich. Durch den Einsatz verschiedener Apparaturen wurden Untersuchungen in statischer und dynamischer Atmosphäre durchgeführt. Es ergaben sich während der Untersuchung Abhängigkeiten der Hydrogenolyse von verschiedenen Reaktionsparametern. Optima der Umsetzung hinsichtlich der Reaktionsparameter Temperatur, Zeit und Ligninanteil in der Schmelze wurden herausgearbeitet. Die Ausbeute an gewünschten Flüssigprodukten wurde, im Untersuchungsbereich, an diesen Punkten maximiert. Gleichzeitig war die Rückstands- und Gasbildung eingeschränkt. Es konnten Erkenntnisse eines komplexen Systems der Abhängigkeiten der Ausbeuten an Reaktionsprodukten von den Parametern der Untersuchung gewonnen werden. Die Hydrogenolyse von Lignin führte zur Aromatisierung fester Residuen sowie zur Abreicherung von Sauerstofffunktionalitäten. Komplexe Reaktionsmechanismen bewirkten den Abbau von Methoxyl-, Carboxyl- und Hydroxylgruppen der Ligninstruktur. Carbeniumionmechanismen konnten als wichtige Reaktionen zur Spaltung von Ether Arylbindungen identifiziert werden. Die Freisetzung von Monomeren und die Polymerisation anderer Intermediäre sind durch Sekundärreaktionen denkbar. Die gebildeten Flüssigprodukte bestanden hauptsächlich aus Monoaromaten (v.a. Guajakole und Kresole) und wenigen Polyaromaten. Die Selektivität der Bildung einzelner Verbindungen war gering, d.h. die Flüssigprodukte sind eine heterogene Mischung mit geringen Konzentrationen der Einzelsubstanzen. Die Unterschiede in der Struktur der Ausgangslignine bildeten sich auch in der Zusammensetzung der Flüssigprodukte ab. / In view of the steadily increasing demand of the chemical industry to base chemicals and the partial uncertain supply of crude oil and gas, it is necessary to find alternative raw materials and conversion routes for the provision of basic chemicals. The aim of the present work was to investigate the hydrogenolysis of lignin in low molecular weight products using appropriate molten salt media. It could be demonstrated that lignin can be convert in low molecular weight products using zinc chloride/potassium chloride molten salt media. The use of an appropriate eutectic melt and of an alternative melt with low melting point proved helpful. By the use of different apparatus investigations in static and dynamic atmosphere could be carried out. During the investigation dependencies of the hydrogenolysis of various reaction parameters are submitted. Optima of the hydrogenolysis regarding to reaction temperature, time and lignin content at the melt could be identified. The yields were maximized at these points in the range of investigation. Concurrently formation of gases and residues were suppressed. Some evidence of a complex system of the dependencies of the yields of reaction products are obtained from the parameters of the investigation. Hydrogenolysis of lignin leads to aromatic solid residues and to a loss of oxygen containing structures. Structures containing methoxyl-, carboxyl- and hydroxyl groups are degraded by various complex reaction mechanisms. Mechanisms of the formation of carbonium ions were identified as important reactions of the cleavage of ether aryl bonds. Secondary reactions caused the liberation of monomers and polymerisation of some intermediaries. The resulting liquid products consist mainly of monoaromatics (guaiacols and cresols) and less of polyaromatics. The selectivity of the formation of single compounds was low, i.e. the liquid products constitute a heterogenous mixture with low concentrations of the single compounds. The structural differencies of the feedstock lignins also showed at the composition of the liquid products.
438

Magnetic Activated Carbon Production from Lignin and Ferrous Salts : Process Modification for Enhanced Phosphate Adsorption from Aqueous Solutions

Zheng, Zhaoran January 2020 (has links)
The treatment and control of superfluous aqueous phosphate is a critical task in environmental management. Magnetic bio-activated carbon is a good adsorbent for physical adsorption methods with several environmental and economic advantages. A streamlined and new method for production of magnetic bio-activated carbon from lignin is finished and presented by Tong Han. To enhance the phosphate adsorption and find the optimization process for mac production from lignin, it’s necessary to investigate influence of process parameters on the quality of the final products systematically. In this work, four different modification of process are used to investigate the influence of process parameters on the quality of the final products systematically, which shows how the proportion of iron oxides, the dispersion of iron oxides and the degree of activation influence the capacities. And the maximum capacity is around 50mg/g, which is a relatively high improvement. / Behandling och kontroll av överflödigt vattenhaltigt fosfat är en kritisk uppgift i miljöhantering. Magnetiskt bioaktiverat kol är ett bra adsorbent för fysiska adsorptionsmetoder med flera miljömässiga och ekonomiska fördelar. En strömlinjeformad och ny metod för produktion av magnetiskt bioaktiverat kol från lignin är färdig och presenteras av Tong Han. För att förbättra fosfatadsorptionen och hitta optimeringsprocessen för mac-produktion från lignin är det nödvändigt att systematiskt undersöka påverkan av processparametrar på kvaliteten på de slutliga produkterna. I detta arbete används fyra olika modifieringar av processen för att systematiskt undersöka påverkan av processparametrar på slutprodukternas kvalitet, vilket visar hur andelen järnoxider, spridningen av järnoxider och graden av aktivering påverkar kapaciteten. Och den maximala kapaciteten är cirka 50 mg / g, vilket är en relativt hög förbättring.
439

Washing efficiency in the pulp mill : An evaluation of the washing efficiency in SCA Munksund's pulp mill / Tvätteffektivitet i massabruket - En utvärdering av tvätteffektiviteten i SCA Munksundsmassabruk

Malmberg, Malin January 2023 (has links)
Munksunds pappersbruk är ett integrerat massa- och pappersbruk som består av två fiberlinjer, en barr- och en lövlinje där båda kokarna är kontinuerliga med efterföljande tvättsteg. En kartering av COD (eng. Chemical Oxygen Demand) och natrium utfördes för båda linjerna för att utvärdera tvätteffektiviteten. COD anger hur mycket syre som krävs för att bryta ned det kvarvarande organiska materialet och natrium används som en indikator på tvättförlusten av kokkemikalierna. Karteringen utfördes genom att analysera in- och utgående flöden vid varje tvättsteg, exklusive kokarna. En förenklad metod användes, där tre flöden analyserades och den fjärde beräknades genom flödes- och massbalanser. Modellen som användes för att beskriva tvätteffektiviteten för respektive utrustning var tvättutbytet Y, som erhölls genom en massbalans. Studien visade att halten COD och Natrium minskar mest från början för respektive linje och når ett gränsvärde runt 8,2 kg COD/adt och 6,6 kg Na/adt för barrlinjen, respektive 8,5 kg COD/adt och 4,8 kg Na/adt för lövlinjen, där ytterligare substans inte kan tvättas bort. Båda linjerna tvättar likvärt med avseende på COD, men lövlinjen tvättar bättre med avseende på natrium. I det sista tvättsteget hade båda fiberlinjerna eliminerat 98% av den inkommande COD-mängden med massan från kokarna. Vidare hade barrlinjen eliminerat 86% och lövlinjen 93% med avseende på natrium i det sista tvättsteget. Utvärderingen av de olika tvättutrustningarna visade att DD-filtret i lövlinjen var effektivast både med avseende på COD och natrium, följt av PO-pressen. På barrlinjen var filter 1 mest effektivt med avseende på COD och natrium. / A mapping of COD (Chemical oxygen demand) and sodium will be done to evaluate the different washing steps. COD describe the amount of oxygen needed to dissolve the organic matter left in the pulp and sodium is used as an indicator of the washing loss of the cooking chemicals. The in- and outgoing streams of the washing steps was analyzed to examine the efficiency. A simplified method was applied where three streams were analyzed and the fourth was calculated through flow-and mass balances. The model used to describe the wash efficiency in this study was the wash yield, which can be obtained by mass balances. The study showed that the content of COD and sodium decreased most in the beginning and reaches a limit value of 8,2 kg COD/adt and 6,6 kg Na/adt in the softwood pulp line and 8,5 kg COD/adt and 4,8 kg Na/adt in the soft wood pulp line, where no more content could be removed. Both pulp lines washed efficient with aspect of COD, but the hardwood pulp line washed more efficient in the aspect of natrium compared to the softwood pulp line. In the last washing step, both pulp lines had removed 98% of the ingoing COD from the digester. With aspect to natrium the softwood pulp line had removed 86% and the hardwood pulp line 93% in the last washing step. The evaluation of the different washing equipment showed that the DD-filter in the hardwood pulp line was the most efficient with aspect of both COD and Sodium, followed by the PO-press. In the softwood pulp line, filter 2 was the most efficient regarding both COD and Sodium. The flow- and mass balances turned out to be complicated at some of the washing steps, especially around the Q1-press in the hardwood pulp line and press 1-3 and filter 2 in the softwood pulp line. The reason for this could be that different functional chemicals are added before the Q1-press, which was not considered in this study, additional causes could be unidentified flows that affect the balances. The study was limited to only analyze three streams and calculate the fourth, an analyze of all the streams would give a more accurate result. However, the study provides a good overview of the wash efficiency in the pulp mill.
440

ASFALTENS FRAMTID UR ETT HÅLLBART PERSPEKTIV / HE FUTURE OF ASPHALT FROM A SUSTAINABLE PERSPECTIVE

Dehghanian, Parmida, Mardani Azari, Deniz January 2022 (has links)
Asphalt is a material used to lay several different types of roads. It has been used in Sweden for more than 200 years. During these years, the work with asphalt has changed, ingredients have been replaced and manufacturing methods have been updated. In modern asphalt, bitumen is used as a binder. It is extracted from crude oil, which is a fossil substance that will not exist forever and also has a bad impact on the environment, therefore people have worked to find new ideas. This report will be about two methods of working for a more sustainable future. The construction and real estate company NCC works with asphalt recycling and the construction company Peab is researching if lignin can be used as a binder. The purpose of this report is to find out which of these methods leaves the least climate footprint. Asphalt is 100% recyclable, but to only use recycled asphalt in new production is not possible, as the quality does not measure up. Lignin is obtained from residual products from the forest industry, which means it is fossil-free. The work with lignin is currently at the research level, so it is not used as standard yet. In order to obtain a result, interviews with people who work at Peab and NCC have been conducted. These people have been able to answer our questions as they work on the topic. Recycling has been used for several decades, therefore the work has come significantly further than the work with lignin which has only been in progress since 2018. For this reason it is difficult to determine which method is most sustainable in the long run. What has been concluded is that when lignin is mixed with bitumen, the durability increases, hence the life-span. We have come to the conclusion that both companies think it is important with recycling, but also that they can see a future with a shortage of recycled asphalt. / Asfalt är ett material som används för att lägga flera olika typer av vägar. Den har använts i Sverige i mer än 200 år. Under dessa år har arbetet med asfalt förändrats, man har bytt ut innehåll och uppdaterat tillverkningsmetoder. I modern asfalt används bitumen som bindemedel. Den utvinns ur råolja vilket är ett fossilt ämne som inte kommer finnas för evigt och har även dålig påverkan på miljön, därför jobbar man för att hitta nya idéer. Denna rapport kommer handla om två metoder där man arbetar för en mer hållbar framtid. Återvinning av asfalt som bygg- och fastighetsföretaget NCC använder sig utav och lignin som bindemedel något som bygg- och anläggningsföretaget Peab forskar på. Syftet med denna rapport är att ta reda på vilken av dessa metoder som lämnar minst klimatavtryck. Asfalt är 100% återvinningsbar men att endast använda återvunnen asfalt i nyproduktion är inte möjligt, då kvaliteten inte håller måtten. Lignin får man fram ur restprodukter från skogsindustrin, den är alltså fossilfri. Arbetet med lignin är i nuläget på forskningsnivå, därför används den inte som standard ännu.  För att få fram ett resultat har bland annat intervjuer med personer som jobbar på Peab och NCC gjorts. Dessa personer har kunnat besvara på våra frågor då de arbetar med ämnet. Återvinning har använts i flera årtionden därför har arbetet kommit betydligt längre än arbetet med lignin som har pågått sedan 2018. Av denna anledning är det svårt att i nuläget avgöra vilken metod som är mest hållbar i längden. Det man har kommit fram till är att när lignin blandas med bitumen ökar hållbarheten, därmed livslängden. I slutsatsen kommer vi fram till att båda företag tycker det är viktigt med återvinning, men även att de kan se en framtid med brist på returasfalt.

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