M. Tech. Mechanical engineering. / Acid deposition is caused by the emission of acidic gases, for example, nitrogen oxides and sulfur dioxide. Nitrogen oxide emissions can be controlled by the proper selection of equipment and operating conditions. Sulfur dioxide on the other hand, can be cleaned by means of procombustion, combustion or post-combustion techniques; the latter being the most effective. The objective of this study is to find suitable additives which will augment the reactivity of lime towards FGD (flue gas desulfurization), while at the same time being easily available at a low price. Zeolite based sorbents yielded the highest reactivity, and all additives, except iron waste, had pozzolanic materials as their main reactive compounds.

<p>Diss. (sammanfattning) Umeå : Umeå universitet, 1993, härtill 7 uppsatser.</p> / digitalisering@umu

L'objectif de cette étude est la diminution du pouvoir de combinaison du dioxyde de soufre des vins blancs liquoreux. La méthode retenue passe par l'élimination du vin de dérivés carbonylés naturellement présents et responsables de la formation de combinaisons bisulfitiques.Les dérivés carbonylés responsables de la plus grande partie du piégeage du dioxyde de soufre sont l'éthanal, l'acide pyruvique et l'acide 2-oxoglutarique. L'extraction de ces composés doit s'effectuer sans dénaturer les qualités organoleptiques du vin et sans générer l'apparition de nouvelles molécules dans le vin. Pour cela, la méthode retenue a été l'extraction liquide-solide : il s’agit de mettre en présence deux réactifs dont l’un l’agent d’extraction est fixé sur un support insoluble. Notre objectif est d’étudier la possibilité de substituer les polymères d’origine industrielle utilisés jusqu’à présent par des supports d’origine naturelle préparés à partir d’un constituant du bois : la lignine. Le recours à des supports d’origine naturelle, dérivé du bois, présente le double intérêt de permettre un meilleur contrôle des matériaux introduits dans le vin à traiter et de rendre les contaminations éventuelles provenant du traitement à priori, plus admissibles, étant constituées de composés déjà présents dans le bois de tonnellerie. / The objective of this study is the reduction of the power of sweet white wines sulfur dioxide combination. The method used relies on the extraction of carbonyl compounds from wine; these are naturally present and responsible for the formation of bisulfite combinations.The carbonyl compounds responsible for most of the trapping of sulfur dioxide are acetaldehyde, pyruvic acid and the 2-oxoglutaric. The extraction of these compounds should be done without altering the organoleptic qualities of wine and without creating the appearance of new molecules in wine. Therefore, the method we used was the liquid-solid extraction: bringing together two reactants, one of which -the extracting agent- is attached to an insoluble support.Our goal is to study the possibility of substituting the industrial polymers, used so far, by natural origin supports, prepared from a wood constituent: the lignin.The use of natural origin materials, deriving from wood, has the double advantage of allowing a better control of materials, introduced in the wine process, and making more acceptable the possible contaminations broad about by the a priori treatment, as they are compounds already present in the wood cooperage.

Made available in DSpace on 2016-06-02T19:55:30Z (GMT). No. of bitstreams: 1 DoutSMP.pdf: 1317200 bytes, checksum: 79dde377784158c00b81b651c941bf26 (MD5) Previous issue date: 2003-06-23 / Universidade Federal de Minas Gerais / A laboratory-scale investigation of SO2 scrubbing was carried out in a 77.92mm (diameter) × 80.00mm trickle bed with 2.00-2.36mm activated carbon particles using continuous and periodically interrupted liquid flows. The effects of cycle period (10 and 20 minutes), cycle split (0.1, 0.2 and 0.3), superficial gas velocity (20, 40 and 60mm/s), and superficial liquid velocity (2mm/s) on SO2 removal and sulfuric acid production were investigated using a simulated flue gas containing SO2 at 500, 1,000 and 1,500ppm. The average removal efficiency of the periodic operation varied from 40 to almost 100%. The major variables controlling periodic operation performance were found to be the superficial gas velocity and the SO2 concentration. The extent of SO2 removal increased with decreasing cycle period and increasing split. Continuous operation runs achieved practically 100% scrubbing efficiency in all tests performed. Sulfuric acid production rates ranged from 0.649×10-8 to 0.256×10-7mol/g catalyst.s. The concentration of sulfuric acid produced was proportional to both the initial SO2 concentration and the gas superficial velocity. Some sulfuric acid production rates data for periodic operation overlapped those obtained in continuous liquid flow experiments. The advantage for the periodic operation was the higher acid concentrations produced and the lower pressure drops across the trickle bed without carbon losses. However, sulfuric acid production should not be regarded as an end in itself for the periodic operation, as the main goal of this gas treatment route is the removal of sulfur dioxide. / O desempenho dos modos periódico e contínuo de operação para o tratamento de uma mistura gasosa de SO2 em ar foi analisado utilizando-se um reator de aço inox, em escala de bancada de 77,92mm de diâmetro interno, contendo leito fixo de carvão ativado de 80,00mm de altura, com partículas de 2,00 a 2,36mm. Foram obtidas as eficiências médias de remoção do gás e as concentrações de ácido sulfúrico produzido nas soluções líquidas de saída, em função da concentração inicial de SO2 (500, 1.000 e 1.500ppm), da velocidade superficial do gás (20, 40 e 60mm/s), da velocidade superficial do líquido (2mm/s) e, no caso da operação periódica, da duração dos ciclos (períodos de 10 e 20 minutos) e da fração de descarga (0,1, 0,2 e 0,3). A eficiência média de remoção da operação periódica variou de 40 a aproximadamente 100%. O desempenho do processo sofreu maior influência da variação da velocidade superficial do gás e de sua concentração inicial. A remoção do dióxido de enxofre foi mais efetiva ao se diminuir o período e se aumentar a fração de descarga. Com a operação contínua foram obtidas eficiências médias de remoção de aproximadamente 100% em todos os casos. As taxas de produção de ácido sulfúrico variaram entre 0,649×10-8 e 0,256×10-7mol/g catalisador.s. Em alguns casos, a operação periódica foi responsável por taxas de produção de ácido sulfúrico maiores que as da operação em estado estacionário. A concentração de ácido produzido foi proporcional à concentração inicial e à velocidade superficial do gás. Os resultados indicam que a vantagem da interrupção periódica do escoamento de líquido é o potencial para produção de ácido sulfúrico mais concentrado com menor perda de carga no leito sem perdas expressivas de carvão. Porém, a produção de ácido sulfúrico não deve ser encarada como um fim em si para a operação periódica, uma vez que o principal objetivo dessa via de tratamento do gás é o abatimento do dióxido de enxofre.

Résumé confidentiel / Résumé confidentiel

Acidification of precipitation is an important environmental problem that emerged during the past century, especially after the Second World War. Acidification was primarily caused by human-made emissions of SOx (mostly SO2) and NOx, which are oxidized sulfur and nitrogen gases. The main sources of anthropogenic SOx emissions are non-ferrous ore refining, and the burning of fossil fuels and biofuels. SO2 emitted to the atmosphere combines with water vapor to produce sulfuric acid, which is one of the main compounds responsible for acid precipitation. In the 1970s and 1980s, more strict regulations regarding emissions of air pollutants such as SOx were established in Western Europe and North America, which led to declining levels of SO2 emissions and by this, declining levels of acidification in surface waters. This project was preformed by assembling and analyzing existing, publicly- available datasets of anthropogenic SO2 emissions for the period 1970 to 2010 from ten different regions in the Northern Hemisphere, and compare them with SO42- concentrations in precipitation and river chemistry in Sweden and Norway for the same period. It was discovered that it is the SO2 emissions from Northwestern Europe, the UK &amp; Ireland and from the USA that have the greatest influence over the SO42- concentration in Scandinavian rivers. The SO42- concentration in stream water is also declining faster than the concentration in precipitation, with a faster decline in the southern parts of Scandinavia. / Försurning av nederbörd är ett miljöproblem som uppstod under det senaste århundradet, särskilt efter andra världskriget. Försurningen orsakades främst av mänskliga utsläpp av SOx (mestadels SO2) och NOx, vilka är oxiderade svavel- och kvävgaser. Huvudkällorna för dessa antropogena SOx-utsläpp är malmförädling samt förbränning av fossila bränslen och biobränslen. SO2 som släpps ut i atmosfären reagerar med vattenånga och bildar svavelsyra, vilket är en av huvudföreningarna ansvarig för sur nederbörd. På 1970- och 1980-talet fastställdes strängare bestämmelser beträffande utsläpp av luftföroreningar (som SOx) i Västra Europa och i Nordamerika. Detta ledde till minskande nivåer av SO2-utsläpp och genom denna sänkning även en minskning av försurning av ytvatten. Det här arbetet utfördes genom att befintlig, offentligt tillgänglig data samlades in och analyserades. Antropogena SO2-utsläpp för perioden 1970-2010 från tio olika regioner på norra halvklotet jämfördes med koncentrationer av SO42- i nederbörd och i vattendrag i Sverige och Norge för samma period. Genom detta fastslogs att de regioner som har störst inflytande över koncentrationen i skandinaviska vattendrag är SO2-utsläpp från nordvästra Europa, Storbritannien och Irland samt från USA. SO42- koncentrationen i vattendragen sjunker också snabbare än koncentrationen i nederbörden, med en snabbare nedgång i de södra delarna av Skandinavien.

Au cours de la conservation du vin en bouteille, des réactions d’oxydation ont lieu et peuvent conduire à des défauts organoleptiques. Les principaux facteurs impliqués dans ces phénomènes d’oxydation sont l’oxygène et les propriétés barrière de l’obturateur. Malgré de récents travaux, ces dix dernières années, sur la quantification des transferts d’oxygène durant le procédé d’élaboration du vin et lors de sa conservation, peu d’études se rapportent aux interactions entre les molécules diffusantes et les matériaux d’obturation. Le matériau étudié dans ce travail est le liège brut, n’ayant subi aucun traitement de lavage ni de surface. Ce manuscrit de thèse aborde le transfert de quelques molécules actives du vin dans le liège, en considérant des transferts en phase gazeuse. Les molécules retenues sont : l’eau, l’éthanol, le dioxyde de soufre et l’oxygène. La thermodynamique d’adsorption de corps purs et de mélanges a principalement été étudiée en réalisant des isothermes d’adsorption en phase gazeuse et des mesures des enthalpies d’adsorption. Tout d’abord, nous avons montré que les mécanismes d’adsorption des corps purs diffèrent selon l’adsorbat. La vapeur d’eau se trouve uniquement physisorbée alors que le dioxyde de soufre et l’éthanol présentent un processus de physisorption et de chimisorption. En outre, des phénomènes de gonflement du liège sont très fortement suspectés dans le cas de l’eau et de l’éthanol. Puis, l’étude de l’adsorption du mélange eau et dioxyde de soufre a montré très clairement que le processus d’adsorption est déplacé en faveur de l’eau. Les quantités faibles de dioxyde de soufre adsorbées ne peuvent alors pas expliquer les pertes de dioxyde de soufre observées lors de la conservation des vins en bouteille. Enfin, l’étude du transfert d’oxygène au travers du liège a été réalisée grâce à une technique manométrique développée au laboratoire associant une approche expérimentale et la modélisation. Pour la première fois un coefficient de diffusion de l’oxygène dans le liège a été déterminé en tenant compte de la variabilité du matériau. / During wine ageing, oxidation reactions occur and can lead to wine sensory defaults. The main factors involved in this phenomenon are oxygen and gas barrier properties of stoppers. During the last ten years, some studies investigated oxygen transfer during winemaking and wine storage. However, only few of them deal with the interactions between molecules and sealing materials. The material studied in this work is raw cork, without any treatment, neither washed nor surface treated (with paraffin or silicone). This Phd work focuses on mass transfer of some wine active molecules, in gas phase, through the cork. The selected molecules are water, ethanol, sulphur dioxide and oxygen. An adsorption thermodynamic study is performed on single compounds and on binary mixture, by means of thermogravimetric and differential calorimetry analysis. Three main results emerge from this study. First we show that the adsorption mechanism of single compounds varies according to the adsorbate. Water molecules are physisorbed whereas ethanol and sulphur dioxide are both physisorbed and chemisorbed. Moreover, a swelling phenomenon is highly suspected for water and ethanol. Then, adsorption of binary mixture of water and sulphur dioxide reveals that the equilibrium is shift in favour of water. Therefore, the small quantity of sulphur dioxide adsorbed cannot explain its concentration decrease during wine storage. Finally, a detailed study of oxygen transfer through cork, carried out by a manometric method developed in our laboratory, combines experimental and modeling approaches. For the first time, a diffusion coefficient of oxygen through cork is given by taking into account the cork material heterogeneity.

This master thesis deals with the feasibility studies desulphurization of powder granulation K3 boiler at Olomouc heating station. K3 boiler burns black energetic coal and after January 1st, 2016 will not meet new more strict emission limits. The theoretical part of the thesis charts usable desulphurization methods from which the semi-dry NID appears as the most appropriate one. In the practical part there is performed a stoichiometric calculation of the flue gas and the balance of raw materials and output products. The possibility of NID method usage is confirmed here. Next the annual operating cost of the desulfurization process is calculated and some NID systems already installed references are presented.

L’utilisation du dioxyde de carbone (CO₂) comme source de composés C1 pour la chimie fine est intéressante d’un point de vue économique et pour des raisons écologiques. Issu de l’oxydation de la matière carbonée, le CO₂ est un gaz non-toxique, abondant et peu coûteux. Sa transformation en produits chimiques présentant de hautes valeurs ajoutées est actuellement entravée par sa stabilité thermodynamique. Afin de développer de nouveaux processus et catalyseurs pour la réduction catalytique du CO₂, une compréhension détaillée des mécanismes réactionnels de l’activation et de la réduction de ce gaz est nécessaire. En utilisant comme catalyseurs des paires de Lewis frustrée (FLPs) contenant une base azotée liée à un ion silicénium, les influences respectives de l’adduit CO₂-FLP et du réducteur ont été déterminées expérimentalement et par calcul DFT dans le cadre de l’hydroboration du CO₂ en équivalent de méthanol. Une nouvelle réaction visant à la création de liaisons carbone–carbone par le transfert du fragment pyridyle de molécules de pyridylsilanes (C₅H₄N–SiMe₃) sur le CO₂ était également étudiée. Le mécanisme réactionnel de cette transformation a été établi sur la base de calculs théoriques. Nous avons montré le double rôle du CO₂ qui est à la fois un réactif et un catalyseur de la réaction de transfert du groupe pyridyle. La compréhension fine de cette réaction nous a permis de l’étendre à la formation de sulfones et sulfonamides qui sont des groupements chimiques essentiels dans le domaine pharmaceutique. En utilisant le SO₂ à la fois comme catalyseur et réactif, des silanes aromatiques et hétéro-aromatiques ont été transformés en sulfones correspondants en une seule étape. Finalement, nous avons trouvé un couplage croisé original, de type Hiyama, entre espèces aromatiques électrophiles et des espèces C(sp2)–Si nucléophiles en présence de SO₂. / The use of CO₂ as a C1 chemical feedstock for the fine chemical industry is interesting both economically and ecologically, as CO₂ is non-toxic, abundant and cheap. Nevertheless, transformations of CO₂ into value-added products is hampered by its high thermodynamic stability and its inertness toward reduction. In order to design new catalysts able to overcome this kinetic challenge, a profound understanding of the reaction mechanisms at play in CO₂ reduction is needed. Using novel N/Si+ frustrated Lewis pairs (FLPs), the influence of CO₂ adducts and different hydroborane reducing agents on the reaction mechanism in the catalytic hydroboration of CO₂ were investigated, both by DFT calculations and experiments. In a second step, the reaction mechanism of a novel reaction for the creation of C–C bonds from CO₂ and pyridylsilanes (C₅H₄N–SiMe₃) was analyzed by DFT calculations. It was shown that CO₂ plays a double role in this transformation, acting both as a catalyst and a C1-building block. The fine understanding of this transformation then led to the development of a novel approach for the synthesis of sulfones and sulfonamides. Starting from SO₂ and aromatic silanes/amine silanes, these products were obtained in a single step under metal-free conditions. Noteworthy, sulfones and sulfonamides are common motifs in organic chemistry and found in a variety of highly important drugs. Finally, this concept was extended to aromatic halides as coupling partners, and it was thus shown for the first time that a sulfonylative Hiyama reaction is a possible approach to the synthesis of sulfones.

Las empresas agroindustriales como Agro-empaques SAFCO S.A.C., realizan un proceso de fumigación a la uva antes de embalarla con el objetivo de garantizar su calidad a lo largo del transporte. Estas empresas usan dióxido de azufre (SO2) como insumo para la fumigación de las jabas de uva dentro de las “cámaras de gasificación”. Sin embargo, debido a su sistema de control rudimentarios e inadecuada operación manual, la empresa afronta sobrecostos y pérdidas económicas. Con el objetivo de solucionar esta problemática, se plantea el presente proyecto que propone el desarrollo de un sistema automático de control y supervisión de la fumigación de la uva con SO2. El sistema contempla diversos subsistemas de control que permiten y garantizan la operación automática de todo el proceso de fumigación. En la etapa de inyección se garantiza el cambio de estado del SO2 (líquido a gaseoso) mediante el control de presión y temperatura; por otro lado, se garantiza el control de la dosis requerida para el proceso fumigación mediante un control de flujo másico totalizado. En la etapa de tratamiento y evacuación se estableció un control de concentración-tiempo que determina el tiempo de fumigación total al cual la uva estará sometida durante el proceso. El sistema implementado cumple con normas de ingeniería nacionales, internacionales y estándares de calidad exigidos por la empresa. Así mismo, está compuesto por diversos periféricos tales como tablero de control, tablero de potencia, equipos de instrumentación y red de comunicación. Estos periféricos en su conjunto permiten el control y supervisión durante todo el proceso de fumigación. / Agro-industrial companies such as Agro-empaques SAFCO S.A.C., carry out fumigation processes on grapes before packing them as a standard procedure to ensure they maintain postharvest quality during transportation. Most commonly, these companies apply sulfur dioxide (SO2) directly to crates of grapes placed in gasification chambers. However, due to its rudimentary control system and inadequate manual operation, the company faces cost overruns and economic losses. This project proposes the development of an automatic control and monitoring system for the fumigation process of grapes with SO2. The system includes various control subsystems that allow and guarantee the automatic operation of the entire fumigation process. In the injection stage, the change of state of SO2 (liquid to gaseous) is guaranteed by means of pressure and temperature control; on the other hand, the control of the dose required for the fumigation process is guaranteed by means of a totalized mass flow control. In the treatment and evacuation stage, a concentration-time control was established that determines the total fumigation time to which the grapes will be subjected during the process. The implemented system complies with national and international engineering standards and quality standards required by the company. Additionally, it is composed of different peripherals such as control panel, power panel, instrumentation equipment and communication network. These peripherals, as a whole, allow the control and supervision throughout the fumigation process. / Tesis