<p>The purpose of this diploma work was to investigate the problem of insufficient fibre recovery in the dissolved air flotation-cell at the new thermomechanical pulping-line at Braviken Paper Mill. An investigation of the effect of process parameters on the removal efficiency in the micro-flotation process was undertaken.</p><p>The experiments were carried out for two setups at the Noss pilot plant with a small-scale flotation unit. Factorial design helped plan the experiments and four factors were controlled; temperature, fibre-size distribution, water quality and feed concentration. Three samples, feed, overflow and filtrate, were taken from each experiment and concentration measurements were made. The results were analyzed using the software MODDE.</p><p>The results from showed an influence from the fibre-size distribution. To see if the fibre-size distribution really had an effect on the results, follow-up experiments were carried out. These experiments showed no influence from temperature, fibre-size distribution or water quality. This concludes that none of those three factors influenced the results significantly.</p><p>Additional experiments were done to examine the influence from concentration and fibre-size distribution on the flotation efficiency and these showed an influence from the feed concentration. When increasing the feed concentration the efficiency of the flotation process decreased.</p>

<p> I viskosprocessens inledande merceriseringssteg behandlas cellulosa (dissolvingmassa) med natriumhydroxid (NaOH) varvid cellulosan omvandlas till alkalicellulosa. Därpå följer en sulfidering med koldisulfid (CS₂) som omvandlar alkalicellulosa till natriumxantogenat. Xantatet löses i en alkalisk lösning och en trögflytande vätska, viskos, bildas. Vid tillverkning av spinnviskos är sista steget i processen en surgörning där koldisulfiden spjälkas av och cellulosan återbildas i form av en tråd. Vid tillverkning av högviskös viskos (Freudenberg HP) sker regenereringen i basisk miljö men vid förhöjd temperatur (100°C), och återbildningen av cellulosa ger då en cellulosabaserad bädd. Genom att öka dissolvingmassans reaktivitet skulle förbrukningen av koldisulfid i sulfideringssteget kunna minskas. Med en ökad reaktivitet menas att fler hydroxylgrupper på cellulosan blir tillgängliga för vidare reaktioner med natriumhydroxid och koldisulfid. Detta skulle kunna möjliggöras med en enzymatisk förbehandling av massan.</p><p>Det första delmålet i projektet var att producera en viskos med hög viskositet i laboratorieskala. Projektets andra mål var att undersöka effekterna av en enzymatisk behandling, med enzymet Carezyme^®, på massans viskositet och reaktivitet.</p><p>En studie gjordes för att se hur olika tider i viskosprocessens andra steg, pressteget, påverkade cellulosahalten och luthalten för alkalicellulosa. Resultaten tydde på att en längre presstid gav en högre cellulosahalt upp till en viss tidpunkt. Vid 195 sekunder avklingade kurvan och effekten av en längre presstid minskade. Resultatet visade också på att mängden lut i alkalicellulosaprovet var relativt konstant och att luthalten inte påverkas nämnvärt av pressningen.</p><p>Vidare genomfördes försök kring viskosprocessens sulfideringssteg. Det fanns under projektets gång stora svårigheter i att uppnå samma höga nivå på gammatalet vid produktion av viskos i laborativ skala (52-58 %) som vid produktion i fabriksskala (68-70 %). Gammatalet är ett mått på hur väl koldisulfid har reagerat med cellulosa under sulfideringen. I ett försök att öka gammatalet satsades en större mängd koldisulfid, med förhoppningen att kunna kompensera för den relativt stora andel koldisulfid som befann sig i gasfas under reaktionen och som därmed inte var aktiv under sulfideringen. Den ökade mängden koldisulfid resulterade dock inte i en ökning av gammatalet. I ett annat försök tillsattes en svag natriumhydroxidlösning direkt till sulfideringskärlet vid avslutad reaktion, utan att någon effekt på gammatalet kunde påvisas. Det undersöktes även om ett ökat förhållande mellan luthalt och cellulosahalt i alkalicellulosan kunde ge någon positiv effekt på gammatalet. Denna förändring gav dock inget ökat gammatal.   </p><p>Dissolvingmassaprover behandlades med enzymet Carezyme^® för att kunna studera dess inverkan på massans reaktivitet och viskositet.  Resultaten visade på en tydlig nedgång i viskositet med högre koncentrationer av enzym. Reaktiviteten på den enzymbehandlade massan ökade i jämförelse med den obehandlade massan. Då viskos producerades med en enzymbehandlad massa kunde ingen effekt av enzymbehandlingen noteras, med avseende på gammatalet.</p><p> </p> / <p>In the first step of the conventional viscose process, called mercerization, cellulose (dissolving pulp) is treated with sodium hydroxide (NaOH) in which the cellulose is converted to alkali cellulose. Alkali cellulose is then treated with carbon disulphide (CS₂) to be converted into a sodium xanthate.  This xanthate is dissolved in an alkali solution and a viscous liquid, called viscose, is formed. The last step in the process is an acidification where the carbon disulphide is splinted off and the cellulose is regenerated in the shape of threads. When producing high viscosity viscose (Freudenberg HP) the regeneration takes place in an alkaline environment and the re-formation of cellulose gives a cellulosic based bed. By increasing the reactivity of the dissolving pulp the amount of carbon disulphide could be reduced, compared at the same degree of substitution. An increase in reactivity means that a larger amount of hydroxyl groups on the cellulose molecule are available to react with sodium hydroxide and carbon disulphide. This could be enabled by an enzymatic pretreatment of the pulp prior to the mercerization step.</p><p>The first aim of this project was to produce a high viscosity viscose in a laboratory scale, comparable to the viscose quality that is produced by Freudenberg HP. The second aim of the project was to investigate the effects of an enzymatic treatment (with the enzyme named Carezyme^®) on the viscosity and reactivity of the dissolving pulp. </p><p>A study was made to examine the influence of the time in the pressing step (after the mercerization) on the cellulose and sodium hydroxide content in the alkali cellulose. The results indicated a linear correlation between the cellulose content and the pressing time up to 195 seconds. At this point the correlation declined and the effects of a longer pressing time decreased. The results also showed that the amount of lye in the alkali cellulose sample was nearly constant and therefore not effected by the pressing time.</p><p>Tests were also carried out concerning the sulphidation step in the process. During the whole project there were difficulties in reaching the same gamma value of the viscose in a laboratory scale (52-58 %) compared to large-scale production (68 - 70%). The gamma value is a measurement of the degree of substitution for carbon disulphide on the cellulose backbone. In one attempt to enhance the gamma value the carbon disulphide charge was increased. The expectation was to compensate for the relatively high amounts of inactive carbon disulphide expected to be found in the gaseous phase in the reactor. However, this did not result in a higher gamma value. In another experiment a weak solution of sodium hydroxide was added directly to the sulphidation vessel after the reaction was completed, but no change in the gamma value was obtained. It was also investigated if an increased relation between the cellulose- and sodium hydroxide content in the alkali cellulose could affect the gamma value positively.  Unfortunately, this modification did not give an increased gamma value.</p><p>Samples of dissolving pulp were treated with the enzyme Carezyme^® to see its impact on viscosity and reactivity of the pulp. The results showed a distinct loss in viscosity with an increased enzyme concentration. The reactivity of the pulp increased compared to the untreated pulp. No effects of the enzymatic treatment could be seen on the final viscose when it was produced from an enzyme treated pulp.</p>

<p>Various chemical properties can be used to characterise dissolving pulp. The quality of the pulp must be carefully controlled to ensure that it meets the requirements for its intended use and the further processes to be applied. If it is to be used to prepare viscose, or other cellulose derivatives, the key prop-erties of the pulp are its accessibility and reactivity. The studies described in this thesis investigated the potential utility of multivariate analysis of chemi-cal and spectral data for determining the properties of dissolving pulp. Dis-solving pulps produced by a two-stage sulfite process, both in the laboratory and a factory were produced pulps for this purpose. The analyses showed that pulp with high reactivity had short cellulose chains, low molecular weight, low polydispersity, low hemicellulose content, high content of ace-tone-extractable compounds, and high surface charge compared to pulp with low reactivity. Important chemical properties of the pulp, such as viscosity and alkali resistance, were successfully predicted from near infrared spectra. Predicting the reactivity, or the viscose filterability, of the pulp was more complex. Several chemical methods for analyzing the reactivity of the pulp were examined. The influence of the cellulose structure at the supermolecu-lar level on the reactivity of the pulp was explored by multivariate analysis of solid state 13C nuclear magnetic resonance spectra. Structural variables considered included: differences in hydrogen bonding, contents of hemicel-lulose, amorphous cellulose and crystalline cellulose I and II. Pulps with high reactivity have higher contents of cellulose I and amorphous cellulose than pulps with low reactivity, which have higher contents of cellulose II and hemicellulose.</p>

No description available.

<p>&nbsp / </p> <p align="left">The domesticated apple (<i><font face="TimesNewRomanPS-ItalicMT">Malus </font><font face="TimesNewRomanPSMT">x </font><i><font face="TimesNewRomanPS-ItalicMT">domestica </font><font face="TimesNewRomanPSMT">Borkh.), belonging to the </font><i><font face="TimesNewRomanPS-ItalicMT">Malus </font><font face="TimesNewRomanPSMT">genus of the Rosaceae family, is one of the edible pomaceous fruits. Since it is one of the important commercial fruit crops worldwide, the quality of the fruit is crucial to breeders and farmers as it ultimately determines acceptance of a cultivar for consumption. Fruit quality is also a critical determinant factor that is used to estimate the potential of apples to have a long shelf life. The introduction of marker-assisted selection (MAS) has allowed hastening of traditional breeding and selection of high-quality apple cultivars. The availability of genetic linkage maps, constructed by positioning molecular markers throughout the apple genome, enables the detection and analysis of major genes and quantitative trait loci (QTLs) contributing to the quality traits of a given genotype.&nbsp / herefore, the primary aim of this study was to construct a genetic linkage map of the &lsquo / Golden Delicious&rsquo / x &lsquo / Dietrich&rsquo / population for the identification of QTLs associated with fruit quality traits and then to examine the apple fruit pulp proteome with a specific focus on fruit firmness. In this regard, genomic DNA was extracted from leaves of the &lsquo / Golden Delicious&rsquo / x Dietrich&rsquo / population and used in megaplex PCR reactions. The PCR products were analysed prior to scoring of alleles. Polymorphic markers were then used to construct genetic linkage maps. The genetic linkage maps constructed in this study comprise of 167 simple sequence repeats (SSR) markers, 33 of these were newly developed markers. The 17 linkage groups of apple were constructed and aligned to existing apple genetic maps. The maps span 1,437.8 cM and 1,491.5 cM for &lsquo / Golden Delicious&rsquo / and &lsquo / Dietrich&rsquo / , respectively.</font></i></i></i></p>

The risk for climate change is a growing concern for theglobal society. According to what is known as the Kyoto Protocol,developed countries have committed themselves to reduce theirgreenhouse gas (GHG) emissions. The purpose of this thesis hasbeen to analyse opportunities for CO2 reductions in Swedish pulpand paper mills. The pulp and paper industry accounts forsignificant shares of the Swedish utilisationof both electricityand, in particular, biomass fuels. In this thesis, it has been agoal to focus not only on the technical potential of alternativesfor CO2 reductions in the energy systems of pulp and paper mills,but also on analysing the costeffectiveness of the studiedmeasures. Moreover, the analysis has covered questions concerningthe capacity and willingness among the actors involved with thepulp and paper mills’energy systems to realise CO2reduction potentials. A broad techno-economical evaluation of available technologiesfor increased power production as well as more efficient energyutilisation is carried out. Furthermore, a more indepth analysisof pulp mill-based biomass energy with CO2 removal and permanentsequestration (BECS) is presented. An evaluation is made of thepotential for pulp and paper production with a negative CO2balance through the implementation of BECS. In recent yearsoutside suppliers, mainly energy service companies (ESCOs), havebegun to operate energy facilities in some Swedish pulp and papermills. Based on interviews with managers from pulp and papercompanies and ESCOs, the main driving forces behind theincreasing co-operation as well as the opportunities and riskswith energy related co-operation are presented. Furthermore, the technical possibility of carbon-negativitythrough the implementation of BECS is discussed in relation tocarbon management on both corporate and global levels. The extentto which CO2-reducing measures in pulp and paper mills arerealised will have an impact on Sweden’s capacity to reachCO2 reduction targets. Whether or not technologies for CO2capture and sequestration are developed and implemented inSwedish pulp mills has a very large impact on the size ofSweden’s long-term CO2 reduction potential. Moreover, thedevelopment of business and competence focus in pulp and papercompanies and ESCOs suggests that cooperation will become ofincreasing importance for future sustainable industrial energymanagement. <b>Keywords:</b>CO2 reduction, pulp and paper industry, energysystem, biomass, CO2 capture and sequestration, black liquor,gasification, power production, outsourcing, sustainable energymanagement

In this thesis, size-exclusion chromatography (SEC) of woodpolymers dissolved in lithium chloride/N,N-dimethylacetamide(LiCl/DMAc) has been used to characterize the molar massdistributions (MMD) of wood polymers in pulp fibers afterchemical degradation. Characterization of birch kraft pulps subjected to ozonedegradation and acid hydrolysis, respectively, rendereddifferent changes in the MMD. Ozone degradation resulted inlarge redistributions of the original MMD, observed as thedevelopment of a distinct fraction of cellulose withintermediate molar mass. Acid hydrolysis resulted in minorchanges of the original MMD compared to ozonation. Fiberssubjected to acid hydrolysis were considerably weaker thanozonated fibers. These results indicated that there aredifferences in how the two chemicals degrade the fiber. The solubility of softwood kraft pulp fibers was enhanced byderivatization of the fiber polymers with ethyl-isocyanateduring simultaneous dissolution in LiCl/DMAc. Thederivatization made it possible to achieve reliable estimationsof the MMD, and hence molar masses, of softwood kraft pulps.The derivatization procedure made it possible to dissolve 90 %of softwood kraft pulps with kappa numbers over 50. Severe alkaline degradation of birch and Norway spruce woodchips was studied both by varying the pulping time and byvarying the initial alkali concentration. Differences werefound in the MMD of the two fiber types, and the alkalinedegradation was found to affect polymers in the entire MMD. Multi-angular laser light scattering (MALLS) was used as adetection technique with SEC on cellulosic samples. The MMD andaverage molar masses obtained through directstandardcalibration with commercial standards were compared with MMDand molar masses as obtained by MALLS-detection. Largediscrepancies were found, and two methods of correcting forthese discrepancies were developed. Theoretical simulations of polymer degradation wereperformed. Random, or homogeneous degradation was used as amodel for alkaline cellulose chain scission, and a resemblancewith experimental data was observed. End-wise depolymerizationof cellulose was also simulated and the results are discussedin the light of experimentally observed MMD. <b>Keywords:</b>cellulose, kraft pulp, birch, spruce,ozonation, acid hydrolysis, degradation, MMD, sizeexclusionchromatography, light scattering, molar mass, chainscission

Various chemical properties can be used to characterise dissolving pulp. The quality of the pulp must be carefully controlled to ensure that it meets the requirements for its intended use and the further processes to be applied. If it is to be used to prepare viscose, or other cellulose derivatives, the key prop-erties of the pulp are its accessibility and reactivity. The studies described in this thesis investigated the potential utility of multivariate analysis of chemi-cal and spectral data for determining the properties of dissolving pulp. Dis-solving pulps produced by a two-stage sulfite process, both in the laboratory and a factory were produced pulps for this purpose. The analyses showed that pulp with high reactivity had short cellulose chains, low molecular weight, low polydispersity, low hemicellulose content, high content of ace-tone-extractable compounds, and high surface charge compared to pulp with low reactivity. Important chemical properties of the pulp, such as viscosity and alkali resistance, were successfully predicted from near infrared spectra. Predicting the reactivity, or the viscose filterability, of the pulp was more complex. Several chemical methods for analyzing the reactivity of the pulp were examined. The influence of the cellulose structure at the supermolecu-lar level on the reactivity of the pulp was explored by multivariate analysis of solid state 13C nuclear magnetic resonance spectra. Structural variables considered included: differences in hydrogen bonding, contents of hemicel-lulose, amorphous cellulose and crystalline cellulose I and II. Pulps with high reactivity have higher contents of cellulose I and amorphous cellulose than pulps with low reactivity, which have higher contents of cellulose II and hemicellulose.

Trashures celebrates my debut in the sustainable world and is my public statement of change. It is essentially provocative, informative and educational and serves three major fronts. First, Trashures aims to raise awareness among visual artists. Second, it seeks to introduce and explore the use of agri-pulp papers in Graphic Design, as a viable commercial solution. Third, it culminates in an invitation to visual artists to search for sustainable solutions. Trashures is about transformations. It highlights the transformation of passive materials into active ones, or the transformation of waste into either papers or as subject matter, as a sustainable way to think over waste and consider it as a potential and genuine resource in Graphic Design.

The recovery boiler in a pulp and paper mill plays a dual role of recovering pulping chemicals and generating steam for either chemical processes or producing electricity. The efficiency of producing steam in the recovery boiler is limited by the first melting temperature of ash deposits that accumulate on the superheater tubes. Above the first melting temperature, the molten salt reacts with the protective oxide film that develops and dissolves it. The most protective oxide is determined by evaluating how little it dissolves and how its solubility changes in the molten salt. Solubility tests were done on several protective oxides in a known salt composition from a recovery boiler that burns hardwood derived fuel. ICP-OES was used to measure concentration of dissolved metal in the exposure tests while EDS and XRD were used to verify chemical compositions in exposure tests. NiO was found to be the least soluble oxide while Cr₂O₃ and Al₂O₃ had similar solubility with Fe₂O₃ being less soluble than Cr₂O₃ but more soluble than NiO. Exposure tests with pure metals and selected alloys indicated that even though Fe₂O₃ has little solubility, it is not a protective oxide and causes severe corrosion in stainless steels. The change in performance of iron based alloys was due to the development of a negative solubility gradient for Fe₂O₃ where Fe₂O₃ precipitated out of solution and created a continuous leaching of oxide. Manganese was found to be beneficial in stainless steels but its role is still unknown. Nickel based alloys were found to be least corroded due to nickel's low solubility and because it did not form a negative solubility gradient.