The structure and composition of denim jeans is complex. In addition to cotton, which is the dominating type of textile fibre, there may be up to about 20 % synthetic fibres. The synthetic fibres are found in the sewing thread and in the elastic yarns that are used to make stretch denim jeans. In total it was found that up to six different types of textile fibres may be present in the material. To be able to recycle cotton in jeans by producing regenerated cellulose fibres a very high purity with respect to cotton is required. The purpose with this project was to investigate the possibility to fractionate the textile material found in denim jeans to obtain a pure cotton fraction that can be used in the viscose process to produce regenerated cellulose fibres, which then can be used to manufacture new clothes. In this project traditional wet mechanical separation equipment found in the pulp and paper industry, in the form of a laboratory screen (used as a model for a pressure screen) and hydrocyclone, was used to fractionate the textile material from cut and shredded denim jeans. The degree of separation of synthetic fibres from cotton fibres was quantitatively evaluated by measuring the glucose content after acid hydrolysis. The results from the experimental work showed that there were runnability problems both regarding disintegration and fractionation. Regarding the fractionation, plugging was found to be a problem and no significant separation of synthetic fibres from cotton fibres was obtained with the conditions of the experiment. / Strukturen och sammansättningen i denimjeans är komplex. Utöver bomull, vilken är den dominerande typen av textilfiber, kan de innehålla upp till 20 % syntetiska fibrer i tyget. De syntetiska fibrerna finns i sytråden och i elastiska garner som används för att tillverka stretchdenimjeans. Den här studien visade att upp till sex olika typer av textilfibrer kan förekomma i materialet. För att kunna återvinna bomull i denimjeans genom att producera regenererade cellulosafibrer krävs en mycket hög renhet med avseende på bomull. Syftet med projektet var att undersöka möjligheten att fraktionera textilmaterialet i denimjeans för att erhålla en ren bomullsfraktion som kan användas i viskosprocessen för att tillverka regenererade textilfibrer, vilka sedan kan användas för att tillverka nya kläder. I projektet användes, inom massa och pappersindustrin traditionell våtmekanisk separationsutrustning i form av en laboratoriesil (här använd som en modell av en trycksil) och en hydrocyklon, för att fraktionera textilmaterialet från klippta och sönderslitna denimjeans. Separationsgraden av syntetiska fibrer från bomullsfibrer bestämdes kvantitativt genom att mäta glukoshalten efter sur hydrolys. Resultatet från det experimentella arbetet visade att det finns körbarhetsproblem både gällande uppslagning och fraktionering. För fraktioneringen visade sig pluggning vara ett problem och ingen signifikant separation av syntetiska fibrer från bomullsfibrer erhölls med förhållandena i experimentet.

Paper and pulp industry and steel industry are two major industries in Sweden, both of which are facing big challenges to treat their waste products properly. In this thesis work, initial evaluation of mechanical properties of briquettes made of waste products was performed. Three different CaO-containing waste products (Mesa, Kalk, Fly Ash) from Stora Enso and SCA were pressed with one kind of binding material (AOD slag) from Outokumpu. Drop tests were carried out to test the impact strength of the lab-made briquettes. Three different parameters were investigated of their influence on the impact strength of the briquettes: 1) Composition of briquettes 2) Heat treatment procedure 3) Exposure time to open air. A total of 97 briquettes were pressed. Drop test results show that for different material based briquettes, heat-treatment and exposure to open air had different influence on the final impact strength. In order to get best impact strength, MB briquettes (90% Mesa +10% AOD slag) heat treated at 850℃, KB briquettes (90% Kalk +10% AOD slag) heat treated at 850℃ and FC briquettes (80% Fly Ash + 20% AOD slag) exposed to open air for 20 days are recommended. Melting experiment was carried out to investigate the sulphur removal ability of the briquettes in metallurgical processes. Thermodynamic calculation of sulphide capacity was done. / Pappers-, massa och stålindustrin är två stora industrier i Sverige, vilka båda står inför stora utmaningar för att hantera sina avfallsprodukter på rätt sätt. I denna avhandling utfördes en första utvärdering av mekaniska egenskaper hos briketter av avfallsprodukter. Tre olika CaO- innehållande avfallsprodukter (Mesa, Kalk, Fly Ash) från Stora Enso och SCA pressades med ett   bindande   material   (AOD   slagg)   från   Outokumpu.   Dropptest   utfördes   för   att   testa slaghållfastheten hos de laboratoriegjorda briketterna. Tre  olika  parametrar  undersöktes  av  deras  påverkan  på  briketternas  slaghållfasthet:  1) Brikets sammansättning 2) Värmebehandlingsförfarande 3) Exponeringstid för friluft. Totalt 97 briketter pressades. Dropptestresultat visar att för olika materialbaserade briketter hade värmebehandling   och   exponering   för   utomhusluft   ett   annat   inflytande   på   den   slutliga slagstyrkan.  För  att  få  bästa  slaghållfasthet,  värmebehandlades  MB-briketter  (90%  Mesa  + 10% AOD-slagg) värmebehandlad vid 850 ° C, KB-briketter (90% Kalk + 10% AOD-slagg) vid 850  °  C  och  FC-briketter  (80%  Fly  Ask  +  20%  AOD  slagg)  utsatt  för  öppen  luft  i  20  dagar rekommenderas. Smältningsexperiment utfördes för att undersöka svavelfjernningsförmågan hos briketterna imetallurgiska processer. Termodynamisk beräkning av sulfidkapacitet gjordes.

På pappersmaskin 11 i Hallsta pappersbruk tillverkas högglansigt papper som bleks med väteperoxid. Om väteperoxiden som finns kvar efter blekningen, kallat restperoxid, kommer ut på pappersmaskinen sliter detta på termovalsarna, vilket påverkar slutprodukten. Det finns en bakteriekultur på bruket, bestående av släktet Tepidiphilus som bryter ner väteperoxiden med hjälp av katalas och hindrar den från att komma ut på maskinen. Om bakterierna slås ut, av exempelvis ogynnsamma förhållanden, märks detta genom att restperoxiden ökar. Målet med detta arbete är att försöka identifiera vilka faktorer som påverkar bakterierna och lägga fram ett förslag för hur man kan förhindra uppkomsten av restperoxid. För att utföra detta användes i första hand principalkomponentanalys, samt så studerades hur olika faktorer förändrades i förhållanden till uppkomsten av restperoxid. Ett antal parametrar kunde identifieras baserat på tillgängliga data. Dock kan inga absoluta slutsatser dras då det inte går att bekräfta några teorier med labbförsök eller genom att manipulera processen. De parametrar som tros ha störst påverkan är mek. renat färg, rest-aluminium, grumlighet, manganhalten i vatten, pH för kar K0203, returmälden samt inloppslådan och klorhalterna som uppmätts för mek. renat total klor, RVV1 fri klor, varmvatten total klor och mek. renat fri klor. Dessa parametrar bör därför övervakas framåt, och kan i det fall att restperoxid återigen uppkommer antingen bekräftas eller dementeras deras faktiska påverkan och samspel för bakteriernas välmående. / Paper machine 11 in Hallsta paper mill produces high-gloss paper that is bleached with hydrogen peroxide. If the hydrogen peroxide that remains after the bleaching, called residual peroxide, gets out on the paper machine, this wears down the thermal rollers, which affects the final product.  There is a bacterial culture at the mill, consisting of the genus Tepidiphilus, which breaks down the hydrogen peroxide with the help of catalase and prevents it from getting out to the machine. If the bacteria are killed, for example by unfavourable conditions, this is noticeable by an increase in residual peroxide. The goal of this project is to try to identify which factors affect the bacteria and put forward a proposal for how to prevent the occurrence of residual peroxide. To carry this out, principal component analysis was primarily used, and how different factors changed in relation to the appearance of residual peroxide was studied. Several parameters could be identified based on the available data. However, no conclusive conclusions could be drawn as it is not possible to confirm any theories with lab tests or by manipulating the process. The parameters believed to have the greatest influence are coloration of mechanically cleaned water (mech. water), residual aluminium, turbidity, manganese content of the water, pH for tank K0203, the returning pulp suspension as well as the headbox and the chlorine levels for mech. water total chlorine, RVV1 free chlorine, hot water total chlorine and mech. water free chlorine. These parameters should therefore be monitored going forward, and if residual peroxide occurs again, their possible interactions and actual impact on the well-being of the bacteria can either be confirmed or denied

The current method for estimating wood failure is highly subjective. Various techniques have been proposed to improve the current protocol, but none have succeeded. This research aims to use deep learning/semantic segmentation using SegNet architecture to estimate wood failure in four types of three-ply plywood from mechanical shear strength specimens. We trained and tested our approach on custom and commercial plywood with bio-based and phenol-formaldehyde adhesives. Shear specimens were prepared and tested. Photographs of 255 shear bonded areas were taken. Forty photographs were used to solicit visual estimates from five human evaluators, and the remaining photographs were used to train the machine learning models. Twelve models were trained with the combination of four image sizes and three dataset splits. In comparison to visual estimates, the model trained on 512 × 512 image size with 90/10 dataset split had a mean absolute error (MAE) of 6%, which was the best among the literature.

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

At present, it is difficult and costly to measure directly greenhouse gas (GHG) emissions from the wastewater treatment system. Application of model will reduce measurement cost and quickly obtain the forecast data set of GHG emissions. This study developed a mathematical model for both steady and dynamic states to calculate GHG (CO2, CH4, and N2O) emissions from wastewater treatment systems for industrial paper processing. These models are constructed based on mass balance equations of species, including substrate balance equations, biomass balance equations for reactors of treatment systems, stoichiometric coefficiences of species in biochemical reactions and biological processes. The obtained equations were solved based on algorithm of Runge-Kutta and the model was programmed by MATLAB. Results of applying the model to calculate GHG emissions from the paper industrial wastewater treatment system at Bai Bang and Tan Mai plants are as follows: total GHG emissions and emission factor are 3,070.3 kgCO2-eq/day, 0.38 kgCO2- eq/m3, respectively for Bai Bang plant (8,000 m3/day) and 7,413.6 kgCO2-eq/day, 0.74 kgCO2- eq/m3, respectively for Tan Mai plant (10,000 m3/day). The research evaluated a number of influencing factors, such as temperature, flow rate of influent, and substrate concentrations, to GHG emissions at the Tan Mai paper plant. / Hiện nay, việc đo đạc trực tiếp phát thải khí nhà kính (KNK) từ hệ thống xử lý nước thải còn khó khăn và tốn kém. Việc áp dụng mô hình sẽ giảm được chi phí đo đạc và nhanh chóng có được bộ số liệu dự báo một cách tương đối về phát thải KNK. Nghiên cứu đã thiết lập được mô hình toán ở trạng thái ổn định và trạng thái không ổn định để tính toán phát thải khí nhà kính (CO2, CH4, N2O) từ hệ thống xử lý nước thải sản xuất giấy. Các mô hình này dựa trên các phương trình cân bằng chất của các cấu tử bao gồm các phương trình cân bằng cơ chất, các phương trình cân bằng sinh khối trong các bể phản ứng và các hệ số tỷ lượng của các chất tham gia các phản ứng sinh hóa. Các phương trình được giải bằng thuật toán Runge-Kutta và mô hình được lập trình trên ngôn ngữ MATLAB. Mô hình được áp dụng tính toán phát thải khí nhà kính từ hệ thống xử lý nước thải tại nhà máy giấy Bãi Bằng và nhà máy giấy Tân Mai, được kết quả như sau: tổng phát thải khí nhà kính (KNK) và hệ số phát thải là 3.070,3 kg CO2-tđ/ngày, 0,38 kg CO2-tđ/m3 tại Nhà máy giấy Bãi Bằng (8.000 m3/ngày) và 7.413,6 kg CO2-tđ/ngày, 0,74 kg CO2-tđ/m3 nhà máy giấy Tân Mai (10.000 m3/ngày). Nghiên cứu đã đánh giá được một số các yếu tố ảnh hưởng như nhiệt độ, lưu lượng nước thải và nồng độ cơ chất dòng vào đến sự phát thải KNK tại nhà máy giấy Tân Mai.

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Utsläpp av CO2 till atmosfären bidrar till ökningen av globala temperaturer. Industrisektorn står för 20 % av utsläppen och utav dessa kommer 6 % från pappers- och massaindustrin. För att lyckas minska den globala temperaturhöjningen till under 1,5 °C hjälper det inte bara att minska utsläppen. Även negativa utsläpp måste genereras. Syftet med denna studie är att undersöka implementeringen av CLG för att separera CO2 på ett energieffektivt sätt och samtidigt generera H2 och elektricitet. Processanalyser genomfördes för att undersöka möjligheten att implementera CLG-processen till ett typiskt massabruk. Processmodeller togs fram for att undersöka CLG, värmeåtervinning samt elektricitetsgenerering. Processmodellerna utvecklades med hjälp av Aspen Plus och Aspen HYSYS. De framtagna modellerna analyserades sedan med avseende på olika designparametrar inom CLG-processen. På ett typiskt massabruk som producerar 800 000 adt varje ˚ar kan 375 kg CO2/adt separeras och då uppnå negativa utsläpp, genom att byta ut multi-fuel forsrännaren med en CLG process. Den framtagna processmodellen skulle också kunna generera 360-504 kWh/adt av H2 beroende på de designparametrar som används för CLG-processen. Enligt modellen kan värme som ˚återvinns från processen användas för att fånga upp ytterligare 13 % av CO2 från andra delar av bruket. Processanalys för olika designparametrar inom CLG systemet så som temperatur, luftflöde och flödet av syrgasbärare har presenterats. Nyckeltalen som undersöktes var den mängd CO2 som kunde fångas upp, mängd H2 genererad samt överskottet av elektricitet som produceras när multi-fuel förbränningen byts ut mot en CLG-process på ett typiskt massa bruk. / Emissions of CO2 to the atmosphere are contributing to the global temperature rise. The industrial sector contributed to 20 % of the emissions and out of that, 6 % are generated from the pulp and paper industry. To limit the temperature increase below 1,5 °C, the emissions not only need to be reduced but also negative emissions should be generated from different sectors. The purpose of this study is to realize the implementation of Chemical Looping Gasification (CLG) to separate CO2 (for permanent storage) in an energy-efficient way while co-generating H2 as well as electricity. Process analysis was carried out to investigate the possibility of substituting the multifuel boiler in a typical pulp mill with a CLG process. Process models for the CLG, heat recovery and electricity generation process were developed using Aspen  Plus and Aspen HYSYS. The process was analysed for different design conditions (temperature, autothermal condition, air flow, oxygen carrier flow) in the CLG process. It was found that in a typical pulp mill producing 800 000 adt per year, 375 kg- CO2/adt (14 % of total emissions from the process) can be inherently separated for storage to achieve negative emissions, if the multi-fuel boiler is replaced with a CLG unit. This process will also be able to generate 360-504 kWh/adt H2 depending on the design conditions in the CLG process. Heat recovered from the CLG unit can be utilized in capturing approximately 13 % additional CO2 from other sources in the pulp mill. Process analysis for different design conditions in CLG (temperature, airflow, oxygen carrier flow) have been presented. The key performance indicators were CO2 capture rates, H2 generated and net electrical output from the process.

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