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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Undersökning av uppkomst, sammansättning och hantering av anodugnsbeläggning

Johansson, Sofia January 2021 (has links)
De senaste åren har Boliden Rönnskär haft problem med beläggningsbildande i anodugnen. Initiala undersökningar har visat på höga nickelhalter, då nickelhalterna förutspås öka de närmaste åren är det av stor vikt att lösa problematiken med anodugnsbeläggningen. Avsikten med detta projekt, är med anledning av detta, att bilda en djupgående förståelse kring beläggningen och dess uppkomst. Detta med huvudsyfte att förhindra bildandet av beläggningen, alternativt finna en metod för att avlägsna redan befintlig beläggning.  För att uppnå målet genomfördes en grundlig karakterisering av beläggningsprover, följt av kartläggning av driftanalyser, karakterisering av driftprov, termodynamiska beräkningar samt försök i labbskala.  Karakteriseringen av beläggningsproverna visade att beläggningen till största del bestod av nickel- järnspineller, men även nickelinnehållande silikatfaser så som nickelinnehållande olivin hittades vid karakteriseringen. Beläggningen innehöll dessutom, viss del kopparoxid samt inneslutningar av metallisk koppar. Karakteriseringen visade vidare på en viss inlösning av anodugnsteglet i beläggningen, samt att flyttemperaturen för de flesta prov var förhållandevis hög (>1400°C).  Kartläggningen av driftanalyser visade på att ökande nickelhalter i blisterkopparen till viss del kunde sammankopplas med en ökning i beläggningsbildandet.  Liknande faser som de i beläggningen hittades vid karakteriseringen av driftprover på tunnslagg, vilka var en silikatfas, en spinellfas, en fas med kopparoxid samt inneslutningar av metalliskkoppar. De termodynamiska beräkningarna visade att spinell- och olivinfaser är termodynamiskt stabila vid jämnvikt under normala driftstemperaturer (1200°C-1250°C) i anodugnen och en syreaktivitet på ~10-7. Beräkningarna visade även att det är termodynamiskt möjligt att med hjälp av tillsatser som soda och kiseldioxid lösa upp redan bildad beläggning.  Resultaten av labbförsöket visade att förhållandena i ugnen varit för reducerande, troligen på grund av användandet av grafitdeglar, vilket medfört att metalloxiderna reducerats ned till metallisk fas. Tegelbitarna som lagts ned i degeln tillsammans med beläggning och tillsatser var dock relativt intakt i samtliga försök, vilket tyder på att tillsatserna inte bör utgöra någon större risk med hänsyn till slitage på teglet i anodugnen vid ett första försök.  Troligt är att beläggningen i anodugnen uppstår genom att tunnslagg från konvertern följer med blisterkopparen till anodugnen och bidrar till beläggningsbildandet. Detta då spinellfasen återfanns även vid karakteriseringen av tunnslaggen. Problemet med beläggningen bör därför kunna minimeras genom att minska mängden tunnslagg som följer med till anodugnen. De termodynamiska beräkningarna visade även att det är möjligt att med hjälp av tillsatser lösa upp redan bildad beläggning. Det är rekommenderat att göra om labbförsöken med ett annat degelmaterial samt kortare tid i ugnen. / During the last few years, Boliden Rönnskär has experienced problems regarding buildup in the anode furnace. Initial examinations of the buildup has shown a high nickel content, since the nickel levels are expected to increase in the nearest future it is of great importance to address the issue of the buildup. The purpose of this project is to gain in-depth knowledge of the buildup and its origin, with the main aim of prevent its development, alternatively find a method to eliminate already existing buildup.  To achieve the aim of the project a thorough characterization of buildup samples was performed, followed by mapping of operational analyzes, characterization of operational samples, thermodynamic calculations and experiments in lab scale. The characterization of the buildup samples showed that the buildup mostly consists of a nickel-iron spinel together with nickel containing silicates like nickel containing olivine. The buildup also consisted of some copper oxide and inclusions of metallic copper. The characterization further indicated that the lining of the furnace to some extent redeems in the buildup. The flow temperature for most samples was relatively high (>1400°C).  The mapping of the operational analyzes indicated that higher nickel content in the blister copper could to some extent be linked to an increase of buildup in the anode furnace.  Similar phases as in the buildup was found in the characterization of the operational samples of slag from the copper-making blow, which were a silicate phase, a spinel phase, copper oxide and metallic copper.  The thermodynamic calculations showed that spinel- and olivine phases are thermodynamically stable at equilibrium and normal operational temperatures in the anode furnace (1200°C-1250°C) and an oxygen activity of ~10-7. The calculations further showed that it is thermodynamically possible to dissolve existing buildup through additives like washing soda and silica.  The results from the lab scale experiments revealed that the environment in the furnace was too reductive, likely due to the usage of graphite crucible; resulting in the metal oxides reducing to the metallic phase. A part of an anode furnace brick was placed in the crucible together with the buildup; this brick remained relatively intact through the experiment, which indicates that the additives should not pose a major risk regarding the wear on the anode furnace lining during a first attempt. It is likely that the buildup in the anode furnace is formed due to slag from the converter accompanying the blister copper to the anode furnace, and thereby contributing to the formation of the buildup. This conclusion was drawn since the same phases were found in both the slag and the buildup. Therefore, the problems with the buildup could be minimized by reducing the amount of slag that accompanies the blister copper to the anode furnace. Furthermore, the thermodynamic calculations showed that it is possible to dissolve existing buildup through additives. However, it is recommended to repeat the lab experiments with shorter time in the furnace or with the use of a different crucible material.
132

Design och tillverkning av automatiserat bryggverk / Design and production of an automatic brewery

Fernandez, Hanna, Johansson, Tova, Renholm, Pontus, Stauber Alfredsson, Malin January 2016 (has links)
Alkoholhaltiga drycker har konsumerats länge i Sverige, idag är öl en av de mest förekommande dryckerna. Med tanke på hur få ingredienser öl innehåller och att smaken trots detta kan varieras i det oändliga är det lätt att förstå att alla delsteg måste genomföras med precision. De olika delstegen i ölbryggningsprocessen är mältning, mäskning, lakning, humlekokning och jäsning. Ett försök till att bygga ett automatiserat bryggverk har gjorts. Komponenter till bryggverket har köpts in och bryggverket har byggts från grunden. Det var inte möjligt att göra alla delsteg i processen automatiserade, till exempel flödesstyrningar och tillsats av ingredienser. Detta gjorde att manuella insatser krävdes. För att styra bryggningen programmerades mikrokontrollerkortet Arduino Uno i programmeringsspråket C. Med hjälp av programmeringen har de delsteg av bryggningen, som går att automatisera, automatiserats. Vid testbryggningen uppstod praktiska problem som inte kunde förutsägas i teorin, exempelvis gick pumpen torrt ibland, reläerna fungerade inte som tänkt samt att en oväntad temperaturgradient uppstod. Dessa problem kan eventuellt lösas med ytterligare insatser i framtida försök. Vidare genomfördes tester innan bryggningen med endast vatten i kärlen för att undersöka temperaturregleringen. Det visade sig dock vara stora skillnader mellan vatten och mäsk, vilket gjorde att dessa tester inte kunde förutsäga alla problem. Trots detta resulterade bryggningen i en besk men drickbar öl.
133

Hantering av avfallskalk från kulsinterverkens rökgasrening i Kiruna - Karakterisering och framtida möjligheter : En idéstudie om hantering och nyttjande av avfallskalk / MANAGEMENT OF WASTE LIME FROM FLUE GAS CLEANING IN IRON ORE PELLETIZING PROCESSES IN KIRUNA : CHARACTERIZATION AND FUTURE OPPORTUNITIES

Malm, Lina January 2022 (has links)
Dagens industrier har ett ansvar att bidra till en hållbar miljö vilket regleras genom lagstiftningar inom områden för utsläpp av föroreningar och avfallshantering. Det kräver bland annat processer för rökgasrening samt en vision för de medförande avfallsströmmarna. Idag sker förbränning av fossila bränslen runt om i världen som leder till utsläpp av svaveloxider, vilket negativt påverkar miljön och människors hälsa. Det finns olika tekniker för avlägsnande av svaveloxider från rökgaser som klassificeras som torra, semi-torra och våta metoder och nyttjar olika kalciumbaserade sorbenter för att avlägsna svavel och resulterar i en renare gas att frige till atmosfären.  Detta arbete syftar till att undersöka hanteringen av den avfallsström som genereras från rökgasreningsprocesser. Detta undersöktes genom kemisk karakterisering, bestämning av mängden oreagerad sorbent och undersökning av potentiella hanteringsmetoder så som termisk behandling eller urtvättning av avfallsströmmen för att identifiera möjliga användningsområden och framtida möjligheter. Projektet har sitt fokus på LKAB:s tre kulsinterverk i Kiruna där huvudfokus ligger på den avfallsström som genereras från svavelreningen, dvs. avfallskalk. Koncentrationsnivåerna av sulfater som återfinns i avfallsströmmarna varierar mellan kulsinterverken. Avfallsströmmarna visar på en sammansättning som tenderar till ett relativt ineffektivt svavelavlägsnande. Alla kulsinterverk har en betydande mängd kvarvarande oreagerad sorbent, Ca(OH)2, som leder till ett oförbrukat material som kan betraktas som en resurs i stället för ett avfall. Avfallsströmmarna från respektive kulsinterverk visade efter den termiska behandlingen en markant mängd CaO som tillsammans med den konstruerade porösa ytan borde utredas för att åter igen nyttjas i processen.  Alternativa hanteringsmetoder för att bidra med en säkrare och miljövänligare hantering och karakterisering av avfall är lika betydelsefullt för ett framtida funktionellt kretslopp. En befuktningssteknik kan förhindra partikelspridning av avfallet samtidigt som det kan ge en kompakt yta vid deponering som även kan vara fördelaktig vid urlakning. Koncentrationsnivåer av klorider och fluorider varierar mellan kulsinterverken som kan ge konsekvenser vid deponihantering. Extraktion av salter kunde genomföras från ett av kulsinterverken vilket leder till ett avfall med minskad kloridhalt som kan vara en miljömässig lösning vid deponering. / Today, the industrial sector has a responsibility to contribute to a sustainable environment which is regulated by corresponding legislation in areas for emission of pollutants and waste disposal. It includes processes for flue gas cleaning and a vision for the resulting waste flow. The combustion of fossil flue uses around the world results in sulfur emissions which negatively affect the environment and humans healthy. Different techniques exist to reduce sulfur oxides from flue gas and were classified as dry, semi-dry and wet methods and use different calcium-based sorbents to remove sulfur oxide and resulting in a purifier gas to release into the atmosphere.   This work aims to investigate the waste stream management generated from the desulfurization processes. This was achieved by chemical characterization, determination of the amount of unreacted sorbent and investigation of potential management methods such as thermal treatment and washing methods of the waste lime to identify the possible area of use and future possibility. The work has focused on LKAB:s three pelletizing plants in Kiruna where the main focus is on the waste stream generated from the desulfurization, i.e., waste lime. The concentration levels of the recovered sulfates in the waste stream variers between the pelletizing plants. The waste stream shows a composition that shows signs of relatively ineffective sulfur removal. All pelletizing plants have a considerable amount of remaining unreacted sorbent, Ca(OH)2, which results in an unused sorbent and can be seen as a resource instead of waste. The waste stream from the respective plant shows a significant amount of CaO after the thermal treatment, together with the constructed porous surface should be investigated to be used again in the process. Alternative management methods to contribute to safer and environment-friendly management and characterization of the waste are equally important for future functional circulation. A humidification technique can prevent the particle distribution of the waste and at the same time give a compact surface with landfilling, which can be advantageous for leaching. The concentration levels of chlorides and fluorides variers between the pelletizing plants and can result in consequences with landfill management. Extraction of salts could be implemented from one of the pelletizing plant and results in waste with decreased chloride content which can be seen as an environmental solution for landfilling.
134

Partitioning of Zn and Cr in Basic Oxygen Steelmaking

Persson, Andreas January 2019 (has links)
Steel is the worlds most used metal and 2016 the produced amount of steel was measured to a total1630 MT where the Blast Furnace (BF) - Basic Oxygen Steelmaking (BOS) process, which is the mostcommon steel process, stands for 75% of the world’s current crude steel production.The BOS process works by blowing oxygen at high velocity through a hot metal bath consisting of hotmetal from the blast furnace mixed with fluxing agents as slag formers and up to 30 weights% scrap.Due to the high focus on environmental aspects throughout the world, the importance of utilizing andrecycling scrap and by-products such as slag and dust has increased. But when byproducts are recycled,the risk of impurities in the refined hot metal increases. To be able to control the impurities and reducethe risk of getting off-specification end product, it is important to understand when and where theimpurities end up.Zinc and chromium are two of these impurities that may cause issues to the process. To prevent thisfrom happening BlueScope Steel, a steel plant based in Wollongong, Australia, with a productioncapacity of 3 million tons of crude steel, wants to find out where these elements come from and howthey partition. For zinc, it is observed that most of it will end up in the offgas, while for chromium it isnoted that the majority exits with the steel and slag. It is assumed for both elements that the missingamount enters with the shredded steel scrap (shred) to meet the required mass balance using industrialdata. Results showed that the shred needs to contain between 0.312% and 0.515% zinc in order tosatisfy the zinc balance for year 2014 to 2019. For chromium, the range is from 0.315% to 0.371%.Data analyses carried out using SIMCA UMETRICS, which is a multivariate program used to performPrincipal Component Analysis (PCA) and Partial Least Squares (PLS) regression, and normal regressionsdone in Excel showed that zinc in the crude steel cannot be used to calculate or predict the partitioningfactors for zinc between slag, melt and off gases, due to a R2 (Goodness of fit) of 0.144, where the highera R2 value is the better the fit to the model. Slag showed better results with an R2 of 0.473 This regressionwas only done for heats with Zn contents above the detection limit, so it will most likely only beapplicable to heats where relatively high amounts of zinc are expected to end up in the slag. The amountof zinc that ends up in the offgas was above 95% for all the heats modelled.For chromium, results for predicting the partitioning between slag and melt showed greater promise,an R2 of 0.663 was obtained for regression of chromium in crude steel, and an R2 of 0.566 was obtainedfor regression of chromia in the slag. Both values are considered acceptable when analyzing plant data.When comparing the two, using the regression from chromium in the crude steel gives a slightly moreaccurate result, with a partitioning difference of only +/- 0.03 and a 97-99% accuracy, compared to +/-0.05 for chromia in the slag with a 95-98% accuracy.The model is used to compare how different amounts of shred will impact the partitioning of the twoelements analyzed. It also looks at how newer generations of filter cake, containing higher amounts ofzinc will impact the partitioning of zinc between the phases, especially the concentration of zinc thatreports to the dust.
135

Investigation of the zinc re-grinding circuit at Boliden Garpenberg

Merum, Nils January 2021 (has links)
Boliden’s mineral processing plant in Garpenberg wanted to investigate their zinc-regrinding circuit. The re-grinding circuit had performed subpar when running as the total recovery of zinc was lowered and problem with the dewatering of the final concentrates was also noted. Therefore, the zinc re-grinding circuit is currently not being used. Furthermore, it was noted during investigations about silicate depressant that the zinc circuit had problems with coarse sized sphalerite particles locked with silica. Which could perhaps be liberated with the re-grinding circuit. The purpose was therefore to investigate how a re-grinding step could be used to liberate locked sphalerite particles from gangue. The practical part of the thesis involved lab-scale SMD-mill, re-grinding of the scavenger concentrate and cleaner tailings which are the two streams being fed to the SMD-mill in the plant. The re-grind was done in three fractions: bulk, +90µm and +125 µm fraction with subsequent lab-scale flotation afterwards to identify how the re-grinding effected the flotation results. Also, a small QEMSCAN analysis was performed for the +90 µm fraction to identify how liberation was improved by re-grinding. The flotation trials were performed with two references and two different intensities for the re-grinds.  The results showed an overall increase in grade of zinc in the concentrate with increased grinding for all the trials. SiO2 and MgO content (typical elements for silicate gangue) was also reduced in the zinc concentrate, showing that re-grinding helped liberate locked sphalerite particles. The QEMSCAN results showed that the liberation of sphalerite particles in the +90 µm fractions increased with re-grinding. For the bulk fraction scavenger concentrate the zinc recovery increased slightly, for the +90 µm fraction scavenger concentrate, a slight decrease in zinc recovery could be seen after re-grinding. The decrease in recovery was larger for the cleaner tailings (bulk and +90 µm) and was decreased further with increased grinding. However, for the +125 µm fraction tests, zinc recovery was increased for both scavenger concentrate and cleaner tailing. The references showed an overall high recovery but a zinc grade in the concentrate close to the feed grade of zinc and contained a high grade of SiO2. Indicating that without re-grinding the amount of free sphalerite is low. Overall, the re-grind and flotation tests pointed towards that value can be created for the plant by re-grinding the scavenger concentrate and cleaner tailing.
136

CO2 Separation - from Aqueous Amine Solvent to Ionic Liquid-based solvent

Wang, Nan January 2021 (has links)
CO2 separation is one of the most important roles in CO2 mitigation target as many human production activities (e.g., cement, iron and steel, and biogas productions) cause CO2 emissions. The solvent-based absorption is the most mature technology for CO2 separation, where different solvents capture CO2 either in chemical or physical absorptions. However, different solvents used in the process always suffer from various problems. For example, the high energy penalty for solvent regeneration, the high solvent loss caused by high volatility and the solvent degradation, and the equipment corrosion are the major concerns of chemical solvent. For the physical solvents, the co-absorption of components other than CO2 reduces the solvent selectivity and increases the operation complexity. Therefore, deeper knowledge about the developed process and new solvent development are the two major ways of overcoming the above-mentioned problems. The goal of this work was to perform systematic studies on both conventional process and novel solvent system(s) for CO2 separation. The CO2 separation with MEA-based process was selected in the field of the conventional approach to capture CO2 from the industrial flues gases. The MEA solvent concentration was identified first, and the effect of three selected parameters, i.e., CO2 concentration, gas flow rate, and CO2 removal rate on capital cost, operational cost, and annual total cost, was evaluated to reduce the energy demand and process cost. 20% MEA solvent is identified as the optimal concentration. According to the parameter study, the CO2 concentration shows the most significant effect, followed by the gas flow rate, and the CO2 removal rate causes the smallest effect. When varying the selected parameters, CAPEX has a greater change in percentage value than OPEX; however, OPEX was the most important one to the total cost owing to its larger absolute value (approximately 3 times of CAPEX). For the solvent development, a conventional polyamine PEHA was selected as it exhibits high thermal stability, low toxicity, and low vapor pressure. Lab testing indicates the 20 wt.% PEHA solution has the best CO2 absorption performance. By using the real bio-syngas from a pilot-scale fixed bed gasifier, the gases other than CO2 (i.e., CO, H2, CH4) were not absorbed in PEHA to any significant extent even at relatively high pressure, and their presence did not affect the CO2 absorption capacity significantly. 20 wt.% PEHA aqueous solvent is a promising chemical solvent for separating CO2 from bio-syngas. For the newly developed novel solvent, ionic liquid (IL) has drawn significant attention as a substitute of conventional solvents due to its superior properties, such as negligible vapor pressure, high thermal stability, and tunable structure. Among many studied ILs, the superbase IL named 1, 8-diazabicyclo-[5,4,0]undec-7-ene imidazole ([HDBU][IM]) shows a very promising CO2 absorption capacity (4.41 mol-CO2/kg-IL), while the high viscosity is a critical issue to cope with. Herein, adding cosolvent was selected as the method to mild the viscosity problem and maintain a high level of CO2 absorption capacity. The dimethyl ethers of polyethylene glycol (DEPG) was selected as the cosolvent of superbase-derived IL [HDBU][IM], and the optimal mass ratio (IL: cosolvent) was identified at 2:1. The temperature effect was studied, showing the high CO2 absorption capacity is favored with low temperature. The effect of gases (CH4, N2) presented in the inlet gas other than CO2 was positive in terms of CO2 selectivity. The thermodynamic modeling agreed well (ARD < 2.37%) with the experimental results. The [HDBU][IM]-DEPG binary system is a promising candidate for separating CO2 from CH4 and N2, and more research will be conducted in the future.
137

Biokol av avfallsfraktioner från IKEA:s möbeltillverkning / Biochar from waste fractions from IKEA’s furniture manufacturing

Ahmed, Safiya, Carlsson, Jesper, Blomberg, Jenny, Wiberg, Filip January 2021 (has links)
I dagens samhälle genereras en stor mängd avfall, där stora delar av avfallen förbränns vilket inte är gynnsamt för vare sig miljön eller klimatet. Därför finns det idag ett stort behov av klimatsmarta metoder där avfallen kan användas till att producera produkter som kan motverka klimatförändringar. Största delen av avfallen som genereras kommer från större företag som till exempel IKEA och de är i ständigt behov av nya metoder för att kunna använda sina avfall till klimatsmarta resurser. Att producera biokol av avfallen är en sådan klimatsmart metod, där biokolet är en hållbar produkt som både motverkar klimatförändringar och andra miljöproblem såsom övergödning. I denna rapport undersöktes två avfallsfraktioner från IKEA, vilka var Dust2k och Hogger. Det som undersöktes var hur lämpliga avfallsfraktionerna från IKEA är för produktion av biokol som skulle kunna appliceras i jordbruket samt hur denna lämplighet påverkas av avfallsfraktion och processförhållanden som används under pyrolysen. För att besvara frågeställningarna utfördes pyrolys på avfallsfraktionerna vid pyrolystemperaturerna 550℃ och 750℃, vilket gav fyra olika prover av biokol. Dessa prov analyserades med ett antal analysmetoder för att avgöra biokolets lämplighet som jordförbättrare och för att motverka klimatförändringar. De analyser som utfördes var elementaranalys, pH-mätning, termogravimetrisk analys (TGA), Brunauer-Emmet-Teller (BET) och svepelektronmikroskopi (SEM). Från pyrolysen och TGA kunde utbytet bestämmas, vilket uppgick till över 20% för samtliga prov. Elementaranalysen visade att biokol producerat av Hogger vid 900°C uppfyllde de EBC-krav som analyserades. Genom att mäta pH på avfallsfraktionerna samt biokolen gick det att se att pH höjdes under pyrolysen. Från BET och SEM erhölls information om porositet, ledningsförmåga och ytarea. Porositeten ökade med temperaturen och ledningsförmågan var högre för biokolet än biomassan. Ytarean låg mellan 347,2 m2/g och 422,8 m2/g och porvolymen mellan 0,173 cm3/g och 0,205 cm3/g. Det erhölls bäst egenskaper för avfallsfraktionen Hogger samt pyrolystemperaturen 750℃, vilket gjorde att slutsatsen att produktion av biokol från Hogger vid 750℃ lämpar sig bäst för användning som jordförbättrare kunde dras.
138

Studies on process synthesis and process integration

Fien, Gert-Jan A. F. 03 August 2007 (has links)
This thesis discusses topics in the field of process engineering that have received much attention over the past twenty years: (1) conceptual process synthesis using heuristic shortcut methods and (2) process integration through heat-exchanger networks and energy-saving power and refrigeration systems. The shortcut methods for conceptual process synthesis presented in Chapter 2, utilize Residue Curve Maps in ternary diagrams and are illustrated with examples of processes for separating azeotropic mixtures. This chapter constitutes a comprehensive review of the most relevant literature of the last twenty years and was itself accepted for publication in Industrial and Engineering Chemistry Research in the Spring of 1994. We demonstrate the usefulness of RCMs as both a tool for teaching the complex techniques necessary for separating azeotropic mixtures and as a practical engineering aid for conceptual design of separation processes. We also give proper clarifications of some traditional misconceptions and contradicting recommendations in the literature. The introduction to and demonstration of process-integration topics in Chapters 3 through 6 are of value to both new and more experienced process engineers. The in-depth treatment of meaningful case studies in Chapters 4, 5 and 6 contain much useful information concerning complex heat-integration and process-retrofit problems. Chapter 4 discusses aspects of multiple-pinch heat-integration problems and ways to tackle them with two of the latest commercial process-integration softwares. Chapter 5 presents a review of and an extension to an Ethylene Plant Retrofit case study taken from the ADVENT Examples Manual (Aspen Technology, 1993), while Chapter 6 does the same for an Ethylene Plant Retrofit case study published earlier by the CACHE Corporation in 1985. / Ph. D.
139

Sieve plate distillation dynamics

Fogle, John Boyden January 1966 (has links)
This dissertation is a study of the composition dynamics of a bench size sieve-plate distillation column. The column was 2-3/4 inches in diameter, 30 inches in length, and contained 10 sieve-plates spaced 2-1/4 inches apart. A benzene-toluene mixture was used as the feed to the column. The pulse testing method for obtaining dynamic information was used. The column was upset by introducing a rectangular pulse increase in benzene composition in the feed stream. The response of each plate was measured in the form of temperature and was converted to a composition response. Frequency response curves were determined for each plate from the pulse response. For the frequency response analysis, the forcing function of a plate was considered to be a weighted sum of the compositions of the liquid and vapor streams entering the stage, while the output function was considered to be the liquid composition on the plate near the exit downcomer. The resulting frequency response was relatively flat in the frequency region of primary interest. The flatness of the frequency response was attributed to poor liquid mixing on tha plates. Based on the experimental observations, a plate in the column may be mathematically represented by a dead time and a steady-state gain. / Ph. D.
140

Desenvolvimento e avaliação de sistemas de controle plantwide aplicados na produção de biodiesel / Plantwide control systems design and evaluation applied to biodiesel production

Silva, Bruno Firmino da, 1989- 06 February 2015 (has links)
Orientadores: Flávio Vasconcelos da Silva, Jones Erni Schmitz / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-27T17:33:20Z (GMT). No. of bitstreams: 1 Silva_BrunoFirminoda_M.pdf: 5897961 bytes, checksum: ac5990dc3d98f600c8592ed2ea843e04 (MD5) Previous issue date: 2015 / Resumo: Os processos químicos apresentam dinâmicas complexas devido a presença de reciclos, integrações energéticas e diversas operações unitárias interconectadas, gerando problemas de interação entre as variáveis e dificultando um efetivo controle do processo. Metodologias de controle global ou plantwide buscam estabelecer sistemas de controle contemplando a planta química como um todo, porém, geram mais de uma solução de controle. Este trabalho propõe avaliar diferentes estruturas de controle global para uma mesma planta química através do uso de indicadores chave de desempenho (KPI ¿ Key Performance Indicator) para o processo, determinando assim qual sistema de controle melhor atende aos objetivos estratégicos da indústria. Como caso de estudo simulou-se uma planta típica para a produção de biodiesel através dos softwares Aspen Plus e Aspen Plus Dynamics. O processo implementado busca representar a produção do biocombustível obtido na transesterificação do óleo de soja com metanol, por meio da rota de catálise alcalina e homogênea. Para simulação dinâmica do processo, utilizaram-se dois conjuntos de controladores obtidos da metodologia de controle global heurística, configurando-se duas propostas de controle para o processo. Para avaliação das propostas de controle, utilizaram-se indicadores chave de desempenho representativos do processo global. O indicador DDS (Dynamic Disturbance Sensitivity), o qual relaciona o acúmulo molar total dos componentes ao longo do tempo, e um indicador que relaciona os custos de matérias-primas foram utilizados. Ambos indicadores, permitiram uma visualização do desempenho dos controladores de modo global e a auxiliaram na escolha do melhor conjunto de malhas de controle para o processo / Abstract: Chemical process have complex dynamics behaviors due to the presence of recycle streams, heat integration and several unit operations interconnected, leading to interaction problems among variables and making difficult to do an effective process control. Plantwide control methodologies aim to establish controls systems for entire chemical plants; however, it is possible to obtain different control solutions. This work proposes an evaluation of different Plantwide control structures for a specific process using Key Performance Indicators (KPI) and determinate which structure best meets the industry strategic goals. As a case study, it was implemented a simulation of a typical biodiesel process in Aspen Plus and Aspen Plus Dynamics. The process implemented intended to represent the production of biofuel obtained from the transesterification of soybean oil with methanol and homogeneous alkaline catalysis as chemical route. For dynamic simulation of the process, two sets of controllers obtained using global control heuristic methodology were used to control the process, setting up two proposals of control for biodiesel production. Key performance indicators of the overall process were used to evaluate the control proposals, such as the DDS indicator (Dynamic Disturbance Sensitivity), which presents the total molar accumulation over time, and an indicator that presents the raw material costs also over time. Both indicators allowed a view of the controllers global performance and aided in choose the best set of control loops for the process / Mestrado / Sistemas de Processos Quimicos e Informatica / Mestre em Engenharia Química

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