[pt] A otimização de processos industriais é uma estratégia para mitigar o impacto ambiental das atividades produtivas. Isso envolve a aplicação de conhecimentos multidisciplinares para aprimorar a eficiência dos processos industriais, reduzindo assim o consumo de recursos naturais, as emissões de poluentes e o desperdício de materiais. A análise exergética tem sido abordada de maneira abrangente na literatura, com inúmeros estudos focados nesse tema. Áreas de pesquisa mais presentes incluem a análise de processos industriais, otimização de sistemas de geração e distribuição de energia, e avaliação da eficiência energética em sistemas de transporte e edifícios. A literatura oferece uma ampla gama de estudos de análise exergética realizados para o forno elétrico a arco (EAF) utilizado na produção de aço. No entanto, há uma necessidade de mais pesquisas voltadas para a aplicação da análise exergética do processo de refino em forno-panela (FP), que representa a segunda etapa do refino secundário na indústria do aço. Um programa em linguagem Python usando o Jupyter notebook foi desenvolvido para calcular o balanço de massa, energético e exergético do refino de aço em forno-panela. Os dados termodinâmicos foram obtidos da base de dados SSUB3 do Thermo-Calc. Os dados reais utilizados foram fornecidos por uma siderúrgica semi-integrada, garantindo a relevância e validade dos resultados. As eficiências energéticas e exergéticas encontradas foram de 92,9 por cento e 90,1 por cento. Os valores de eficiência são surpreendentes pois revelam que o forno em análise está otimizado. As otimizações foram conduzidas para examinar variações na massa de argônio, temperatura de entrada de argônio e potência ativa do eletrodo. As variações destes parâmetros revelaram pequenos impactos na eficiência do processo, proporcionando ideias para aprimoramentos efetivos. / [en] The optimization of industrial processes is an interesting strategy to mitigate the environmental impact of productive activities. It involves applying multidisciplinary knowledge to improve the efficiency of industrial processes, thereby reducing the consumption of natural resources, pollutant emissions, and material waste. Exergy analysis has been extensively addressed in the literature, with numerous studies focused on this topic. The most prevalent research areas include analyzing industrial processes, optimizing energy generation and distribution systems, and assessing energy efficiency in transportation systems and buildings. The literature provides various exergy analysis studies conducted for electric arc furnaces (EAF) used in steel production. However, there is a need for more research focused on applying exergy analysis to the ladle furnace (LF) refining process, which represents the second stage of secondary steel refining in the industry. A Python program using Jupyter Notebook was developed to calculate steel refinement s mass, energy, and exergy balances in a ladle furnace. Thermodynamic data were obtained from the SSUB3 database of Thermo-Calc. A semi-integrated steel mill provided the actual data used, ensuring the results relevance and validity. The energy and exergy efficiencies found were 92.9 percent and 90.1 percent, respectively. These efficiency values are surprising, as they reveal that the furnace under analysis is already optimized. Optimizations were conducted to examine variations in argon s mass and inlet temperature, as well as electrode active power. The parameters variations revealed minor impacts on process efficiency, providing insights for effective improvements.

<p dir="ltr">This thesis explores novel methods of steel reheating, simulating hydrogen as a cleaner fuel in the combustion furnace and magnetic induction heating as a viable alternative, by utilizing advanced numerical simulations, including Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA), to assess their performance and feasibility.</p><p dir="ltr">Hydrogen, known for its potential to significantly reduce carbon dioxide emissions, is examined as a substitute for natural gas. Simulations revealed that hydrogen combustion results in higher flame temperatures and heat fluxes. While the CFD model achieved a high level of accuracy, with a maximum temperature error of 3% and an average deviation of 7% from real-world data, hydrogen fuel caused an increase in heat flux by up to 12% and higher slab surface temperatures. These changes led to steeper thermal gradients and increased stress, with peak stress levels reaching 90% of material limit. This simulation approach provides valuable data on the performance of different furnace fuels, helping to identify optimal fuel blends and configurations that minimize the risk of material failure while enhancing furnace efficiency.</p><p dir="ltr">The impact of scale formation on steel surfaces during reheating was also investigated. A mathematical model based on linear-parabolic equations was integrated into CFD simulations to predict scale growth. This model was validated against experimental data, showing an average error of 6%. The presence of scale led to a reduction in core temperature by up to 31 K and a 7.6% decrease in heat flux, which negatively affected heating efficiency. Scale formation also caused a significant drop in thermal conductivity, impacting heat transfer and slab uniformity. Pre-heating zone contributed minimally to overall scale formation despite its extended duration whereas a majority of scale growth was observed in the heating zone. Applications of this model include improving reheat furnace model efficiency and optimizing furnace operation to minimize scale.</p><p dir="ltr">Magnetic induction heating was also explored as an alternative to combustion-based reheating, assessing its potential benefits and challenges. The simulation results, validated with an average error of approximately 7% compared to literature data. showed uniform temperature distribution, and reduced stress levels with optimal power settings around 80 kW. A 3D transient simulation modeled an adaptive power cycle to minimize thermal stress highlighting the effectiveness of adaptive soaking strategies over continuous soaking in managing thermal stress, improving heating efficiency and material integrity.</p>

With increased climate goals, higher demands are placed on the construction industry to reduce emissions, making it important to develop alternatives that are economically and environmentally sustainable. Concrete is one of the most widely used materials and has high CO2-emissions, with cement production accounting for 90% of these emissions. Therefore various types of green concrete have been developed, where one of the alternative binders approved according to Swedish standards is ground granulated blast furnace slag (GGBS). The impact of GGBS in concrete is well documented and researched, with known advantages and disadvantages of using green concrete. The aim has been to gather relevant data of how GGBS affects the concrete performance and durability. The results show that there are tsignificant effects when using slag concrete, with GGBS providing good resistance against chemical attacks and achieving higher strength. However, there are questions regarding how sustainable GGBS actually is, especially considering how the steel industry is evolving and moving from blast furnaces to fossil free steel production in electric arc furnaces. Nevertheless, GGBS is of utmost relevance for climate improvement within the construction industry. Where the transition within the steel and construction industries opens up opportunities for the development of innovative technologies and new binders to minimize the climate footprint of cement production, thereby paving the way for a sustainable future. / Med ökade klimatmål ställs högre krav på byggindustrin att minska utsläppen, varav det är av vikt att utveckla alternativ som är ekonomiskt och miljömässigt hållbara. Betong som är ett av de mest använda materialen har höga CO2-utsläpp, där tillverkningen av cement står för 90% av utsläppen. Därför har det utvecklats olika typer av klimatförbättrad betong, där ett av de alternativa bindemedlen som är godkänt enligt svenska standarder är masugnsslagg. Slaggens inverkan på betong är väldokumenterad och undersökt, där man vet att det finns fördelar och nackdelar med att använda en klimatförbättrad betong. Syftet har varit att ta fram relevant data om hur masugnsslagg påverkar betongen prestandan och hållbarhet. Där resultatet visar att det finns påtagliga effekter med att använda slaggbetong, där slaggen ger en god beständighet mot kemiska angrepp och kan uppnå högre hållfasthet. Det existerar dock frågetecken hur hållbar masugnslaggen är, detta med avseende på hur stålindustrin utvecklar sig och kommer gå från masugnar till fossilfri ståltillverkning i ljusbågsugnar. I dagsläget är dock masugnslaggen av högsta relevans för klimatförbättringen inom byggindustrin. Där omställningen inom stål- och byggindustrin öppnar upp för utvecklingen av innovativa tekniker och nya bindemedel för att kunna minimera klimatavtrycket från cementproduktionen, och därmed bana väg för en hållbar framtid.

Eine umweltverträgliche Methode der Rückgewinnung anorganischer industrieller Abfallprodukte bietet die thermische Behandlung im elektrischen Lichtbogenofen. Hierbei wird der Abfallstoff geschmolzen und die enthaltenen Schwermetalloxide reduziert und von der mineralischen Phase abgetrennt. Der Prozess ist sehr energieaufwändig und noch nicht vollständig verstanden. Die laserinduzierte Plasmaspektroskopie (LIBS) soll als in situ-Messtechnik dabei helfen, das Verständnis zu verbessern und die Methode zu optimieren. In theoretischen Untersuchungen wurde gezeigt, dass die Güte von LIBS-Messungen durch Normierung auch mit einer gesättigten Linie eines Matrixelementes verbessert werden kann. Für LIBS-Messungen im elektrischen Lichtbogenofen wurde ein mobiles Doppelpuls-LIBS-System für industrielle Bedingungen entwickelt, getestet und optimiert. Als Modellsystem für Schlacken wurden dotierte Glasproben verwendet. Für festes und flüssiges Glas wurden Nachweisgrenzen im ppm-Bereich erreicht, was für die Gehalte in Schlackeproben ausreicht. Ferner wurden zwei Methoden entwickelt, Flüssigkeiten mit Hilfe von festen Standards zu quantifizieren. Um die Empfindlichkeit von LIBS zu verbessern, wurde Doppelpuls-LIBS untersucht. Es konnte eine Verstärkung des Signals um das 5,1-fache erreicht werden. Es konnten Emissionen der Moleküle CaCl, MgO, YO und ZrO in LIBS-Plasmen identifiziert und simuliert werden. Eine mögliche Verwendung der Molekülemissionen stellt die Quantifizierung sehr hoher Elementgehalte dar. Trotz der schwierigen experimentellen Bedingungen erwies sich das LIBS-System als empfindlich genug. Es wurde schrittweise Mangan- und Chromoxid zur Schmelze gegeben, was in einen linearen Anstieg der LIBS-Signale resultierte. Die Reduktion und Separation von Chrom gelang und konnte mit LIBS verfolgt werden, was durch die Referenzanalysen bestätigt wurde. / The reduction process in the electric arc furnace offers a sustainable method to recover industrial inorganic waste materials. The material is molten and the containing heavy metals are reduced and separated from the mineral phase. The energy consumption of the process is very high and the detailed reactions and dynamics are not yet fully understood. Laser induced breakdown spectroscopy can provide online-measurements inside a furnace, enabling us to increase understanding and optimize the process. In a theoretical investigation it has been shown that intensity fluctuations of LIBS can be compensated by normalizing the line used for analysis with a saturated line from a matrix element. For LIBS-measurements inside the electric arc furnace, a mobile double pulse LIBS-system designed for an industrial environment was built and tested. Glass was used as a model system for slags due to its lower melting point. Limits of detection in the ppm-region were achieved for solid and liquid glass, which is sufficient sensitivity for recycling slags. Furthermore, two methods were developed to quantify a liquid using solids as standards. To improve the sensitivity of LIBS, double-pulse measurements were conducted. Signal enhancements of up to 5.1 were achieved compared to single pulse. In the LIBS plasma emissions of molucules CaCl, MgO, YO and ZrO were identified and their emissions simulated. These emissions could be used to quantify large element concentrations. Despite the difficult experimental conditions the sensitivity of the LIBS-System has been found to be sufficient for recycling-slags. When stepwise adding manganese and chromium oxide to the melt, the respective LIBS intensity increased linearly. The reduction and separation of chromium was successful, which was confirmed by reference analysis.

A method of producing steel that is not used in Sweden today is direct reduction using natural gas, a method which could has enormous potential in the future of steelmaking. Historically, steelmaking prioritized productivity and profitability. However, other aspects such as safety, sustainability, and environmentally friendliness have become increasingly important to Swedish steelmakers. This study evaluates the usage of natural gas to  directly reduce iron ore into the porous form known as iron sponge, then finally processing that sponge into crude steel. The technology available today is assessed through a literature review, then two calculative data-based model: using DRI sponge in a traditional integrated steelmaking line or replacing steel scrap with it in an electric arc furnace. While this technology is used in many regions where natural gas is plentiful, it has not yet been used in Sweden. Now, when the Swedish natural gas network is expanding and the vehicular transportation of liquid natural gas is becoming more and more viable, it is a prime situation to evaluate direct reduction in Sweden. While models require assumptions and estimations, they suggest that DRI will absolutely be a viable option in the years to come. Integrated plant operators can reduce their immense carbon emissions for a reasonable price, while DRI sponge melting in an electrical arc furnace can either help steelmakers escape the volatile scrap market or be used to replace the blast furnace as a whole in the future. / En metod för att producera stål som inte används i Sverige idag är direkt reduktion med hjälp av naturgas, en metod som har en enorm potential i framtida ståltillverkning. Historiskt har ståltillverkningen prioriterat produktivitet och vinst, men säkerhet, hållbarhet, och miljövänlighet har blivit områden mer och mer viktiga för svenska ståltillverkare. Den här studien utvärderar användningen av naturgas för att direkt reducera järnmalm till den porösa formen känd som järnsvamp, och sen bearbeta den till primärt stål. Teknologin som flnns idag utvärderas genom en litteraturstudie, vars data beräknas till två scenariomodeller: användningen av järnsvamp i ett traditionellt integrerat stålverk eller genom att ersätta stålskrot med järnsvamp i ljusbågsungen. Den här teknologin används redan idag i regioner där naturgas är lättillgängligt, men har hittills inte använts i Sverige. Men nu när Sveriges naturgasnät byggs ut och fordonstransporterad flytande naturgas blir mer och mer kostnadseffektiv så är det lämpligt att utvärdera direkt reduktion i Sverige. Modellerna kräver antaganden och uppskattningar, men de pekar på att direkt reducering av järnmalm kommer att vara en genomförbar metod för ståltillverkning i en nära framtid. Integrerade masugnslinjer kan minska sina enorma koldioxidutsläpp till ett rimligt pris, och järnsvampssmältning i ljusbågsugn kan hjälpa ståltillverkare att undanfly den instabila stålskrotsmarknaden eller användas för att helt ersätta masugnsproduktion i framtiden.

Магистерская диссертация посвящена разработке программного обеспечения автоматизированного рабочего места (АРМа) технолога доменного цеха, которое позволяет сформировать технический отчет о работе доменного цеха за отчетный период (месяц/год) с использованием web-приложения. В ходе работы рассмотрены основные этапы реализации программного модуля: анализ предметной области, проектирование и программная реализация web-приложения. В ходе разработки программного обеспечения АРМа спроектированы и реализованы серверная часть системы и web-приложение на платформе ASP.NET Core. Серверная часть включает базу данных, которая является не только местом хранения данных, но и частично реализует функции бизнес логики. Приложение позволяет технологу доменного цеха с помощью пользовательских форм сопровождать базу данных отчетных показателей работы доменного цеха и формировать технический отчет за определенный месяц и сохранять в различных форматах. Научная новизна полученных в работе результатов заключается в разработке методов эффективной организации, ведения процесса разработки и сопровождения специализированного информационного, алгоритмического и программного обеспечения АИС АППС ДЦ, включая базу данных доменного цеха и средства создания технического отчета доменного цеха: использование гибкой методологии разработки (Agile, SCRUM) и таск-трекера Atlassian JIRA для ведения проекта, взаимодействия с заказчиком во время разработки, отслеживания ошибок, визуального отображения задач и мониторинга процесса их выполнения; функциональное моделирование процессов и подсистем для реализации web-приложения подготовки технического отчета доменного цеха на основе методологии IDEF0 и средства реализации Ramus Educational; использование методики коллективного владения программным кодом на основе сервиса (удаленного репозитория) GitHub. Практическая значимость результатов заключается в том, что разработанное программное обеспечение позволит: производить автоматизированный сбор и подготовку необходимых отчетных данных о работе доменного цеха за нормативный период (месяц); специалистам инженерно-технологической группы доменного цеха сократить время на формирование отчетных документов, сократить время поиска необходимой фактической отчетной информации за счет реализации эргономичного web-интерфейса; специалистам отдела сопровождения информационных систем снизить трудозатраты на сопровождение, совершенствование и развитие системы с учетом пожеланий пользователей. Результаты работы могут быть использованы также в учебном процессе для обучения бакалавров и магистрантов по направлению «Информационные системы и технологии». Результаты работы представлены и обсуждены на международных и всероссийских конференциях: VII, VIII и IX Всероссийской научно-практической конференции студентов, аспирантов и молодых учёных (Екатеринбург, УрФУ, 2018, 2019, 2021); XII Всероссийской научно-практической конференции (Новокузнецк, СибГИУ, 2019); 77-й международной научно-технической конференции «Актуальные проблемы современной науки, техники и образования» (Магнитогорск, МГТУ, 2019). / The master's thesis is devoted to the development of software for an automated workstation (AWP) of a blast furnace shop technologist, which allows you to generate a technical report on the operation of a blast furnace shop for a reporting period (month / year) using a web application. In the course of the work, the main stages of the implementation of the software module were considered: analysis of the subject area, design and software implementation of a web application. During the development of the AWP software, the server part of the system and the web application on the ASP.NET Core platform were designed and implemented. The server part includes a database, which is not only a place for storing data, but also partially implements the functions of business logic. The application allows the technologist of the blast furnace shop, using user-defined forms, to accompany the database of reporting indicators of the blast furnace shop operation and generate a technical report for a specific month and save it in various formats. The scientific novelty of the results obtained in the work lies in the development of methods for effective organization, maintenance of the development process and maintenance of specialized information, algorithmic and software AIS APPS DC, including the blast furnace shop database and tools for creating a technical report of the blast furnace shop: - use of flexible development methodology (Agile, SCRUM) and the Atlassian JIRA task tracker for project management, interaction with the customer during development, tracking errors, visual display of tasks and monitoring the process of their implementation; - functional modeling of processes and subsystems for the implementation of a web application for preparing a technical report for a blast furnace shop based on the IDEF0 methodology and Ramus Educational implementation tools; - using the method of collective ownership of the program code based on the service (remote repository) GitHub. The practical significance of the results lies in the fact that the developed software will allow: - to carry out automated collection and preparation of the necessary reporting data on the operation of the blast furnace shop for the regulatory period (month); - for specialists of the blast-furnace shop engineering and technological group to reduce the time for the formation of reporting documents, to reduce the search time for the necessary actual reporting information due to the implementation of an ergonomic web interface; - specialists of the information systems support department to reduce labor costs for maintenance, improvement and development of the system, taking into account the wishes of users. The results of the work can also be used in the educational process for training bachelors and undergraduates in the direction of "Information systems and technologies". The results of the work are presented and discussed at international and all-Russian conferences: VII, VIII and IX All-Russian scientific-practical conference of students, graduate students and young scientists (Yekaterinburg, UrFU, 2018, 2019, 2021); XII All-Russian Scientific and Practical Conference (Novokuznetsk, SibGIU, 2019); 77th international scientific and technical conference "Actual problems of modern science, technology and education" (Magnitogorsk, MSTU, 2019).

Steel production is today one of the most CO2-demanding activities and causes 8% of the global emissions of GHG. It is crucial for the industry to reduce its emissions radically in order to be in line with the goals of the Paris Agreement and the Science-Based Target initiative. Ovako AB, one of the leading producers of high-strength engineering steel, has been at the forefront when it comes to sustainability initiatives within the industry. Heavy investments are being made into sustainable steel production methods and technologies and to make this viable, the company has, from January 1st, 2022, started to put a price premium on their steel products of 30 € per tonne. This study aims to answer the question of how Ovako's customers, based on the three different industries of mining, automotive, and bearing, experience this price premium and how a green steel can justify this surcharge. Furthermore, this case study aims to understand the extent to which those customers require carbon neutrality when sourcing steel. Connected to the findings from the innovation theories and the literature, this study aims to answer the question of how sustainable innovations may influence future competitiveness regarding engineering steel. To answer these questions, interviews with key individuals from different customers of Ovako were conducted. Moreover, focus groups at Ovako with relevant employees have been held at the same time as a literature study has been conducted. Based on the answers obtained from the data collection, a thematic analysis has been performed where overarching themes have been identified. Additionally, a carbon impact calculator has been used to calculate the carbon reduction potential of using a carbon-neutral engineering steel in three different applications connected to the three industries investigated, namely a complete bearing, a drill bit, and a final drive unit. The results from the calculations as well as the answers obtained regarding the research questions will be presented in the conclusion chapter of the report.

La pyrolyse rapide de différents types de celluloses, lignines, xylanes ainsi que de mélanges synthétiques obtenus à partir de ces composés modèles et aussi de deux biomasses réelles (bois de bouleau et paille de blé), est étudiée dans un four à image. Les vitesses de perte de masse pour les composés modèles étudiés sont très différentes, de manière générale la plus grande vitesse de perte de masse est observée pour la cellulose, suivie du xylane et de la lignine. La lignine se distingue par un temps de début de réaction plus petit que celui observé pour le xylane et la cellulose. Pour un temps donné, le rendement en charbon est plus grand pour la lignine que pour le xylane. La formation de charbon à partir de la cellulose est marginale. La cellulose microgranulaire produit en majorité des vapeurs et très peu de gaz. La cellulose extraite du bois de bouleau montre un comportement intermédiaire entre le comportement de la cellulose microgranulaire et les lignines. Le xylane se distingue par une vitesse de formation de gaz supérieure à celles des vapeurs. Les mélanges synthétiques à partir des trois composés modèles montrent un comportement intermédiaire. Le bois de bouleau est plus réactif que la paille de blé et son comportement peut être comparé à celui de la cellulose extraite du bois de bouleau en ce qui concerne les vitesses de perte de masse et de formation de vapeurs. Une corrélation simple se basant sur l’addition pondérée des vitesses de formation des produits est établie et les résultats obtenus sont comparés aux résultats expérimentaux. Il s’avère que les inorganiques jouent un rôle important lors de la pyrolyse : le comportement de la paille de blé, une biomasse riche en inorganiques, ne peut pas être décrit par de telles corrélations. Des écarts moins significatifs entre les valeurs obtenues par les corrélations théoriques et celles provenant des résultats expérimentaux sont observés pour les mélanges synthétiques et le bois de bouleau. En conclusion, l’hypothèse d’une corrélation simple, appelée loi prévisionnelle, ne semble pas être justifiée sur les vitesses de formation de produits. Un modèle est alors développé qui permet de décrire le comportement pyrolytique à l’aide de courbes non linéaires pour la perte de masse et la production des produits. A l’exception de la paille de blé, de nouvelles lois prévisionnelles additives peuvent alors être déterminées de manière très satisfaisante au regard de la précision des mesures expérimentales / The fast pyrolysis of different types of celluloses, lignins, xylanes as well as different mixtures of these basic compounds and two real biomasses (birch wood and wheat straw) has been studied in an image furnace. The mass loss rates of each of the studied model compounds are very different, but usually higher for cellulose than xylane and higher for xylane than lignins. Lignins begin to react before xylane and cellulose. For a given pyrolysis time, lignins produce more char than xylane. Char formation from cellulose remains insignificant, close to zero. Microgranular cellulose gives mainly rise to vapours and very little gas is formed. Cellulose extracted from birch wood shows an intermediate behaviour between microgranular cellulose and lignins. Production rates of gases are higher than those of vapours for xylan. Regarding the mixtures of these three compounds, an intermediate behaviour can be observed. Birch wood is more reactive than wheat straw. Its pyrolytic behaviour is similar with that of cellulose extracted from birch wood with regard to concerning mass loss rates and vapours formation. A simple additive correlation relying on mass loss rates and products formations rates is elaborated and the results compared to the experimental values. It appears that inorganics play an important role in biomass pyrolysis : the pyrolytic behaviour of wheat straw, a biomass which is rich in inorganics, cannot be described by simple additive correlations. Less significant gaps between expected rates obtained by the correlations and the observed rates obtained by the experiments are found for synthetic mixtures and birch wood. In conclusion, the hypothesis of linear correlations cannot be supported for representing the products formations rates. A complete mathematical model is then developed revealing a non-linear behaviour of the variations of mass losses and products formations. Except for wheat straw, new additive correlations are then determined. The agreement with the experimental results is very satisfying with regard to the measurements accuracies

La pyrolyse primaire rapide de cellulose, lignine, xylane et bois de bouleau (réel, reconstitué, lavé ou non) imprégnés par différents types de catalyseurs (KCl, MgCl2, NiCl2 et ZnCl2) est étudiée expérimentalement dans un four à image. De manière générale, l’effet résultant de l’ajout d’un catalyseur diffère selon le type de biopolymère. Il entraine cependant toujours la diminution de la vitesse de production des liquides et l’augmentation de celle des charbons (effets plus ou moins accentués selon la nature du catalyseur). La composition de phase gazeuse est également modifiée avec augmentation de la fraction volumique en H2. La nature et la morphologie des charbons dépendent également du type de catalyseur. Pour la cellulose, on montre que la quantité et la composition du composé intermédiaire liquide produit lors de la pyrolyse sont également modifiées. Des lois linéaires de comportement pyrolytique établies à partir de la simple superposition des observations faites avec les biopolymères pris isolément n’ont pu être établies avec précision, ce qui implique une phrase de modélisation. Le modèle repose sur l’écriture de bilans de matière et d’énergie au niveau des pastilles de biomasses soumises à une densité de flux de chaleur imposée. L’accord avec les résultats expérimentaux est satisfaisant mais souffre d’une mauvaise connaissance des propriétés physico-chimiques des biomasses. Les écarts proviennent également de la non prise en compte des interactions entre les biopolymères au sein des biomasses réelles. Des actions de recherche dans ces domaines pourraient être recommandées / The fast primary pyrolysis of cellulose, lignin, xylan and birch wood (natural, reconstituted, washed or not) impregnated by different types of catalysts (KCl, MgCl2, NiCl2 and ZnCl2) is experimentally studied in an image furnace. The effect of a catalyst addition differs according to the type of biopolymer. However, the decrease of the liquids and the increase of the char production rates are always observed (the effects are more or less stressed according to the nature of the catalyst). The composition of the gaseous phase is also modified with an increase of the H2 volume fraction. The nature and morphology of chars depend on the type of catalyst. The quantity and composition of the intermediate liquid compound formed during the pyrolysis of cellulose are also modified. It’s difficult to establish linear laws describing the pyrolytic behavior of biomasses from the simple overlapping of the observations made with basic biopolymers, implying the need of a modelling study. The model is based on mass and energy balances written at the level of biomasses pellets subjected to a given heat flux density. The agreement with the experimental results is quite good but suffers from a bad knowledge of the physicochemical properties of the biomasses. It is anticipated that the model could give better results if the influence of the interactions between basic biopolymers within the natural biomasses could be estimated and taken into account. Some researches in these domains could be recommended

Este trabalho consiste no estudo da obtenção de aglomerados autorredutores na forma de briquetes a frio tratados termicamente, utilizando minério de ferro e carvão fóssil como matérias-primas. Esta promissora tecnologia tem como premissa a utilização da termo-plasticidade do carvão fóssil para conferir resistência e promover a auto-aglomeração. A obtenção de briquetes dá-se através de três etapas: condicionamento da mistura, briquetagem a frio e tratamento térmico. Os finos de carvão e minério são misturados e homogeneizados. A mistura, então, passa por processo de briquetagem a frio para compactação, promove o aumento de contato entre as partículas de carvão e minério. Finalmente tratamento térmico é realizado para obter a forma de um corpo sólido e coeso de auto-aglomerado autorredutor. O objetivo deste trabalho é determinar as melhores condições de obtenção de briquetes através do estudo de variáveis ao longo do processo de fabricação, utilizando a resistência mecânica como parâmetro. As variáveis estudadas são: granulometria do carvão, envelhecimento do carvão, percentual de carvão na mistura, adição de aglomerantes, pressão de compactação na briquetagem e temperatura de tratamento térmico. Os resultados obtidos neste estudo indicam que estas variáveis afetam significativamente a resistência mecânica. Utilizando-se o carvão Chipanga, o melhor resultado de resistência à compressão foi de 19,82 Mpa. Foram consideradas as seguintes condições de fabricação: mistura na proporção de 75:25 (% em massa) de minério para carvão Chipanga, o carvão continha finos inferiores à 0,075 mm, sem a adição de aglomerantes, e o tratamento térmico foi realizado na temperatura de máxima fluidez do carvão. Além disto, foi observado que as partículas de minério de ferro foram concentradas nas regiões periféricas do briquete após tratamento térmico, e que o envelhecimento do carvão afeta negativamente a propriedade de termo-plasticidade. / This work is focused in the study of obtaining self-reducing cold briquettes of agglomerates, by using iron ore and coal as raw materials. This promising technology has its foundation on the thermo plasticity of coal to manage high mechanical resistance when it is compared with self-reducing pellets. Three steps mainly describes how to obtaining briquettes: mixture, cold briquetting and heat treatment. Fines of raw material are mixed and cold briquetting process results in a compact mixture. This might lead to closer contact between particles of iron ore and coal. Finally, heat treatment is performed to achieve a cohesive body and solid shape containing self-reducing agglomerated. The main purpose of this job is to comprehend the fundamentals on how to obtain self-reducing cold briquettes of agglomerated carbon and iron, by understanding the background of it variables along the manufacturing process, and using mechanical resistance as reference. The variables list is: the particle size of the coal, coal aging, percentage of coal in the mixture, adding binders, briquetting pressure and temperature of heat treatment. The results of this study indicate that these variables affect significantly the mechanical strength. Using Chipanga coal, the best compressive strength achieved was 19.82 MPa. It was considered the following manufacturing variables: the mixture ratio of 75:25 (wt% of iron ore and coal), fines of coal containing less than 0.075 mm, without binders, and heat treatment was performed at the temperature of coal´s maximum fluidity. Moreover, it was observed that the particles of iron ore were concentrated in the peripheral regions of the briquette after heat treatment, and that coal´s aging negatively affects the property of thermo-plasticity.