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This report describe the wear of the protruding areas on the sides of the grate plates in the grate-kiln process in the hematite pellet production in LKAB, Kiruna. The steel plates are exposed to a hostile environment with heat cycles and corrosive atmosphere. An evaluation of the plates was made in co-operation with LKAB Metlab in Luleå and LKAB mechanical workshop in Kiruna. Instruments used are stereomicroscope, LOM, SEM, Spectroscope, Vickers Hardness and a surface nish meter. Results show the protruding areas of the plates are exposed to a tribochemical wear, where tops of the rough areas are torn down. A coating test is carried out at Tribolab, LTU in Luleå, using an SRV. Samples with a wear and corrosion resistant coating called Diamalloy 4276 abrade against eachother at high temperature and pressure. The coating do help to resist wear, but the environment of the test is to unrealistic to say by certain that it will help in the grate. A FEM-model in COMSOL Multiphysics 4.4 is made to calculate thermal stresses between coating and metal, the result show stresses up to 1 GPa will occur, this can be explain by the big dierence in thermal expansion coefficients of the materials. It will probably create cracks in the coating surface. Two solutions are presented, a coating is not recommended. The tribochemical wear is decreased by using a better surface nish. Therefore one can either machine the areas by drilling or milling, or one can change the casting method. Today sand casting is used, by using shell casting or precision casting, for example Shaw process, the surface nish is better over the whole plate, which also is better for corrosion resistance since less initiation points exist. / Denna rapport presenterar en undersökning av slitaget på sidorna av grateplattor som används i gratekilnprocessen i hematitpelletstillverkningen på LKAB i Kiruna, även lösningar presenteras. Plattorna benner sig i en svår miljö med termiska cykler och korrosiva substanser. Utvärderingen av slitaget gjordes i samarbete med LKAB Metlab i Luleå och LKAB mekaniska verkstad i Kiruna. Utrustning som användes var Stereomikroskop, LOM, SEM, Spektroskop, Vickers hårdhetsmätare och ytnhetsmätare. Resultatet visar att sidorna av plattorna utsetts för ett tribokemiskt slitage där toppar av den grova utan slits ner. Ett ytbeläggningstest utfördes på Tribolab, LTU i Luleå, med en SRV. Prover med en beläggning har gnidits mot varandra under tryck och hög temperatur och jämförts med prover utan beläggning som utsattes för samma test. Ytbeläggningen som används står främst emot korrosion, men även slitage, den kallas Diamalloy 4276. Resultatet visar att beläggningen skyddar bra mot slitage, men miljön under testet var för orealistiskt för att med säkerhet kunna säga att det kommer hjälpa i graten. En FEM-modell gjordes med hjälp av COMSOL Multiphysics 4.4 för att beräkna de termiska spänningarna som uppstår mellan ytbeläggningen och metallen. Resultatet visar att spänningar på upp till 1 GPa kommer uppstå, detta kan förklaras med den stora skillnaden i termisk utvidgningskoecient mellan de två materialen. De höga spänningarna kan skapa sprickor i ytan. Två lösningar presenteras, en ytbeläggning rekommenderas inte i dagsläget. Det tribokemiska slitaget kan motverkas genom att förbättra ytnheten. Detta kan antingen utföras genom att bearbeta ytan, med fräsning eller slipning, eller att man byter gjutningsmetod. Idag används manuell formtillverkning, om man istället skulle använda skalformsgjutning eller precisionsgjutning, till exempel Shawprocessen, skulle man få en bättre ytnhet över hela plattan. Detta leder även till bättre korrosionsbeständighet då färre initieringspunkter nns.

In this study a setup is designed and constructed in the Hydromechanics Laboratory of Middle East Technical University in order to observe the flow through grate inlets under different flow and geometry conditions. The rate of interception of flow is determined over a rectangular channel through preliminary experiments run on the tilting flume. The performance of the new set setup has been examined and grate efficiency is obtained both in terms of longitudinal slope and the Froude number. The results which are obtained show that the setup can be used to conduct experiments to obtain a general expression for grate efficiency.

Luossavaara-Kiirunavaara Aktiebolag (LKAB) är en gruvdriftskoncern med järnmalmsbrytning som huvudsaklig verksamhet. En av produkterna tas fram genom att raffinera järnmalm till pellets vilket är en efterfrågad produkt vid ståltillverkning.   Vid sintring av råkulor till pellets är temperaturen väsentlig för att få så hög oxidation som möjligt av magnetit till hematit och för att få rätt fasthet. För att reglera värmen bör temperaturen mätas bland råkulorna eftersom det är kulornas temperatur som är det viktiga.                                   Projektet går ut på att undersöka möjligheterna att mäta temperatur bland råkulor på gratevagnar som åker genom en pelletsugn med ett permanent mätsystem. Här ställs höga krav på mätsystemet på grund av miljö, portabilitet och drifttid. Miljöanalyser gjordes för att ta reda på vilken påfrestning ett mätsystem bör klara av. Förslag om placering av mätutrustning framtogs genom kartläggning av miljön. En värmeundersökning utfördes av vad hög värme har för påverkan på elektroniska komponenter som kan behövas till ett mätsystem. Det gjordes även en undersökning över vilka komponenter som kan klara av den värme ett mätsystem kan bli utsatt för. Utifrån detta kunde ett prototypmätsystem konstrueras för att mäta temperaturen där ett mätsystem kan placeras på en gratevagn samt för att skapa möjlighet för mätningar med termoelement i bädd. Mätsystemet skapades med trådlös kommunikation, möjlighet till loggning av data och med möjlighet att ansluta tre termoelement av typ S. Olika typer av trådlös kommunikation utvärderades för att se vad som kan vara mest lämpat med tanke på miljö, räckvidd, strålning och strömförbrukning. Strömförsörjning undersöktes för att hitta den mest lämpade strömförsörjningen med längst drifttid och högst funktionalitet. En utredning gjordes för att hitta monteringsmöjligheter av ett mätsystem på en gratevagn. Värmeavskärmning och isolering undersöktes för att få ner temperaturen i kapslingen och för elektroniken i ett mätsystem. Några olika temperaturgivare granskades för att hitta en som klarar av att mäta temperaturer upp till 1500°C och som fysiskt kan monteras på en gratevagn. / Luossavaara-Kiirunavaara Aktiebolag (LKAB) is a mining group with iron ore mining as the main business. One of the products is produced by refining iron ore to iron pellets, which is a quality and environmentally clever product  in steel production.                                     When iron pellets are produced by roasting green pellets the temperature is very important. The goal is to get as much oxidation as possible from hematite to magnetite and to get correct mechanical properties. To control the process it’s important to know the temperature of the green pellets specifically and not the surrounding mechanical structure, ceramics lining in the furnace and the influence from radiation.   The goal of the project is to examine possibilities to measure temperature with a permanent measurement system of green pellets which are transported on grate cars trough pellet plant. The measurement system has to meet some requirements of environment, portability and operating time. Analysis of the environment has been made to get specification of what a measurement system has to withstand. Proposition about assembly location has been investigated by analysis of the environment. A thermal analysis has been made of electronic components, especially electronic components that can be used in a measurement system. A analysis has also been made of which electronic components that are suited for a measurement system and can withstand the heat. A development measurement system has been developed from the results of the analysis. The system has been constructed to measure the temperature of what a system can be exposed of on a grate car. This with wireless and data-logging support and future measurements possibilities with three thermocouples of type S.   Wireless data transfer was examined to see what type is most suited for the task with knowledge of environment, transmission range, radiation and power consumption. Power sources was examined to find a power source with longest working time and highest functionality. Heat insulation and reflective materials has been investigated with the goal to get the temperature in the system enclosure as low as possible. Some different types of temperature sensors that can measure temperatures up to 1500°C and which can be mounted on a grate car has been evaluated.

The thesis is dedicated to the design of the steam boiler which burns wood chips, with a natural circulation of the water. It is a grate boiler, which produces 20 t/h of the steam. The output parameters of the steam are 420 °C and 5 MPa. The feedwater temperature is 125 ° C .The thesis gradually deals with stoichiometric calculations and determines the efficiency of the boiler. Then it describes the design of the fireplace and thermal calculations of each heat transfer surfaces. The appendix includes drawings of the boiler.

Many reports, scientific papers, patents, and scientific news investigate the feasibility and affordability of direct carbon dioxide capture from the atmospheric air (DAC). Since carbon dioxide (CO2) is extremely diluted in the atmosphere, large volumes of air have to be handled to capture comparable amounts of CO2. Therefore, both the energy consumption and the plant size are expected to be 'prohibitive'. On the other hand, some analyses have shown that DAC is feasible and can become affordable with essential research and development. DAC has been regarded as an optional bridging or a transitional technology for mitigating CO2 emissions in the medium-term. Priorities include investing in renewable and low-carbon technologies, efficiency and integration of energy systems, and realisation of additional environmental benefits. A heavy reliance on negative emission technologies (NETs), and consequently DAC, may be extremely risky as NETs interact with a number of societal challenges, i.e. food, land, water and energy security. Although, "... capturing carbon from thin air may turn out to be our last line of defence, if climate change is as bad as the climate scientists say, and if humanity fails to take the cheaper and more sensible option that may still be available today" MacKay (2009). Certainly, more research is necessary to bring down both cost and energy requirements for DAC. This work firstly predicts the adsorption equilibrium behaviour of a novel temperature swing adsorption process, which captures carbon dioxide directly from the air, concentrates, and purifies it at levels compatible to geological storage. The process consists of an adsorption air contactor, a compression and purification train, which is a series of packed beds reduced in size and connected in-line for the compression and purification purposes, and a final storage bed. The in-line beds undergo subsequent adsorption and desorption states. The final desorbed stream is stored in a storage bed. This cyclic process is repeated for a number of times imposed by the required purity and pressure in the final bed. The process is been thermodynamically verified and optimised. Since, the overall performance of this process does not only depend on the design of the process cycle and operating conditions but also on the chosen adsorbent material, further optimisation of the adsorptive and physical properties of the solid adsorbent is investigated. Thus, the optimal parameters of the potentially used porous materials is identified. Continuing the research on different adsorbent materials, an experimental investigation on the equilibrium properties of two competitive adsorbents is also performed. Besides the thermodynamic analysis, a dynamic model is presented for the investigation of the mass and heat transfer and its influence on the adsorption rate and consequently on the overall process performance. Since the initial stream is very dilute, it is expected that the adsorption rate will be low compared to other temperature swing processes and the capture rate will be affected by the heat transfer. Finally, the design and development of an experimental laboratory-scale apparatus is presented and analysed. Future design improvements are also discussed.

In this research we are following the thermo-chemical degradation of wood in the absence of oxygen. The objectives are to evaluate the influence of heating rates on pyrolysis products obtained from wood pyrolysis and to evaluate the influence of acid pre-treatment on pyrolysis products. Depending on the wood heating rates, pyrolysis can be categorized as Flash pyrolysis, Fast pyrolysis, and Slow pyrolysis. We have evaluated the volatile products obtained at different heating rates and the volatile products obtained from sulfuric acid pre-treatment by using gas chromatography- mass spectrometry (GC-MS). We have also performed thermo-gravimetric analysis (TGA) of raw wood samples and sulfuric acid pre-treated wood samples of Yellow Pine to determine the changes in weight in relation to change in temperature. Our results indicated that by using the Flash, Fast, and Slow heating rates, the overall volatile products obtained from wood pyrolysis (i.e. the overall list of all the compounds obtained from different temperature ranges in wood pyrolysis by using different heating rates) were the same, but the volatile products obtained at different temperature ranges like Room temperature-300°C, 300°C - 400°C, and 400°C -500°C in Flash, Fast, and Slow pyrolysis were different. Most of the volatile products obtained from the pyrolysis of untreated wood were phenols. Our results also indicated that the pretreatment of wood with sulfuric acid alters the charcoal properties and releases gaseous products including furan derivatives that are useful as fuels or fuel additives. The sulfuric acid (10%) pretreatment of wood followed by slow pyrolysis produced maximum yield of charcoal, indicated by the lowest mass % decrease of 58.234. The production of furan derivatives increased by using sulfuric acid pre-treatment, which is a good improvement for the production of Furanics, the furan based biofuels. The furan based biofuels are of increasing research interest because of their significant advantages over the first generation biofuels. The thermogravimetric analysis (TGA) results indicated that the acid pre-treatment altered the decomposition rate of pyrolysis and lowered the onset of temperature for decomposition. The use of thermal degradation of plants for creating chemicals and fuels is seeing renewed interest across the globe as it is considered carbon-neutral and it uses a renewable feedstock. The information obtained from this research work will also be valued by industries, such as charcoal and activated carbon producers, which currently perform biomass pyrolysis, by allowing them to form approaches that optimize their energy use and minimize waste.

This work deals with the creation of a numerical model of a biomass combusting chamber on a grate. The research part of this work describes the basic properties of biomass important for its combustion and the biomass combustion process itself. For this process which it is necessary to know the dynamics of the chemical reactions and the overall mechanism of a grate combustion of fuels. It also describes the production of harmful emissions that can be generated by combustion of biomass and the emphasis is mainly on the production of nitrogen oxides. In the next part is described the combustion device itself and the basic mathematical model which incorporates the mechanisms of heat transfer, flow of fluids and transport of chemical species. The basic mathematical model is then extended to a complete mathematical model by determining the initial and boundary conditions. Subsequently, the results of the computer simulation of the mathematical model are presented and commented. The main focus are the emissions of nitrogen oxides and hydrocarbons. These results are used to design an improvement of the geometry of the combustion chamber.

This master thesis deals with the properties of digestate in combustion, design of construction solution of digestate boiler and experimental verification of boiler parameters. The first chapter deals with the properties of digestate as a fuel. It is followed by a chapter dealing with the existing measured results on a similar boiler. This is followed by a stoichiometric calculation of the digestate boiler. The next chapter is devoted to combustion chamber models. This chapter is followed by a chapter with experimental verification of chamber models and combustion process tuning. The last chapter contains design of construction and operational measures.

At present, people already fully aware of how expensive it is energy dependence on fossil fuels. Trying to reduce this dependence goes hand in hand with environmental limits, which restrict the production of dangerous compounds. Biomass is a fuel that does not create large amounts of sulfur and carbon dioxide generated during combustion is in a closed cycle. Different types of biomass have different calorific value, and therefore different demands on the quantity needed to produce MWh. It is therefore necessary to choose the fuel with regard to the availability of in the site.