Este trabalho de pesquisa visa estudar o processo de formação das emissões gasosas num motor de combustão interna movido à álcool e analisar os fatores que contribuem para o controle dessas emissões em níveis estabelecidos pela legislação. Especial atenção foi dada à aplicação de conversores catalíticos platina/paládio como auxiliar no processo de controle das emissões gasosas automotivas. Foram realizados ensaios dinanométricos de um motor de combustão interna para analisar as emissões e o controle destas, em condições operacionais, em função da razão ar-combustível, ponto de ignição e rotação. O conversor catalítico contribuiu para redução de mais de 80% das emissões gasosas danosas à saúde, quando o motor operava em condições estequiométricas. Observou-se a necessidade de desenvolver o sistema de admissão e descarga do motor para receber o catalisador sem que este cause redução considerável à queda da eficiência volumétrica do motor. / This work of research aim analyzes process of formation of gas emissions in alcohol internal combustion engines and analyses factors that contribute to control those emissions in level established by legislation. Special attention was faced application of catalytic converters platin/palladium with auxiliary in the process of control emissions gas automotives. Assays dynamometric were realized of to analyses emission and control them, in conditions operation ales, in function of air-fuel ratio, point of ignition and rotation the catalytic converters contribute to reduction more of 80% of emissions gas that cause damage health, when observed that necessity of develop system of admission and exhaust of engines to receive catalysts out that provocate reduction considerable decrease of efficiency volumetric of engines.

Au cours du cycle réplicatif des rétrovirus, l’ADN viral rétro-transcrit est intégré dans l’ADN de la cellule hôte par l’intégrase virale (IN). L’IN possède un rôle clé dans le cycle rétroviral et représente une cible thérapeutique majeure pour le traitement des infections par le virus de l’immunodéficience humaine (VIH). L’IN est constituée de trois domaines (N-terminal, central et C-terminal) connectés par des boucles flexibles, qui la rendent difficilement cristallisable. Le Dr. C. Ronfort (Equipe Rétrovirus et Intégration Rétrovirale) et le Pr. P. Gouet (Laboratoire de BioCristallographie) collaborent depuis 2002 sur l’IN du Rous Associated Virus type 1 (RAV-1). Mes travaux de thèse s’inscrivent dans le cadre de cette collaboration. Il s’agissait de mener une étude cristallographique et moléculaire du domaine central de l’IN du RAV-1 pour pouvoir, ensuite, modéliser des mutants d’intérêt identifiés par l’équipe du Dr. C. Ronfort. Pour ce faire, le fragment protéique a été surproduit et purifié. Sa structure cristallographique a été résolue à une résolution de 1,8 Å. L’examen de cette structure révèle que le dimère de l’IN du RAV-1 peut s’assembler suivant une nouvelle interface moléculaire stabilisée par trois paires d’hélices α. Cet assemblage se caractérise également par la présence d’un étroit sillon basique à sa surface. Par des expériences in vitro de biochimie et in silico de docking, nous avons montré que ce sillon était susceptible de fixer un brin d’ARN. D’autre part, nos données expérimentales permettent d’expliquer comment les conditions de cristallisation, ainsi que la substitution d’un acide aminé de surface, favorisent la formation soit de ce nouvel arrangement dimérique, soit de l’arrangement dimérique classique. Ainsi, l’ensemble des données obtenues au cours de cette thèse suggère que l’intégrase possède des propriétés structurales modulables, lui permettant d’intervenir dans plusieurs étapes du cycle rétroviral en présence d’ADNdb (intégration) ou d’ARNsb (rétro-transcription et/ou encapsidation du génome ARN viral) / During the replicative cycle of retroviruses, the retrotranscribed viral DNA is integrated into the host chromosome by the viral integrase protein (IN). The integration reaction is essential for the viral life cycle. Therefore, IN is a key target for antiretroviral drug design to treat HIV infection. IN consists of three domains (N-terminal, central and Cterminal) connected by flexible loops, making the enzyme difficult to crystallize. Dr C. Ronfort (Team Retrovirus and Retroviral Integration) and Pr P. Gouet (BioCrystallography Laboratory) collaborate since 2002 in Lyon to study IN from the Rous Associated Virus type 1 (RAV-1). My thesis work lies within this collaboration. Its objective was to perform crystallographic and molecular studies of the central domain of RAV-1 IN and of mutants of interest identified by the team of Dr C. Ronfort. In this aim, the IN fragment has been overexpressed and purified. Its crystal structure has been solved to a resolution of 1.8 Å. The observation of this structure reveals that the RAV-1 IN can exhibit a novel dimeric arrangement with a molecular interface stabilized by three pairs of facing α-helices. This arrangement is also characterized by the presence of a basic narrow groove at its surface. Thanks to biochemical in vitro experiments and in silico docking studies, we have shown that this median groove could allow the binding of a linear singlestranded RNA. Moreover, our experimental data can explain how the crystallization conditions as well as the mutation of a specific residue located at the surface of the enzyme favor either this novel dimeric arrangement or the classical dimeric interface. Therefore, the data obtained during this thesis suggest that IN exhibits modular structural properties, allowing it to operate in several distinct steps of the retroviral cycle in presence of dsDNA (integration) or ssRNA (reverse transcription and/or encapsidation of the retroviral RNA genome)

PetrÃleo Brasileiro S/A / O objetivo principal à determinar a atividade catalÃtica residual e as causas da desativaÃÃo de amostras de catalisadores de uma unidade de HDT de lubrificantes. Foram realizadas corridas em unidade piloto, caracterizaÃÃo dos catalisadores e coletados dados do histÃrico operacional da unidade industrial. A atividade catalÃtica foi determinada atravÃs das conversÃes das reaÃÃes de HDA, HDS e HDN bem como pelos parÃmetros cinÃticos aparentes de um modelo de lei das potÃncias e lei de Arrhenius. Os catalisadores dos leitos principais de entrada e saÃda dos reatores industrial foram os mais desativados e o menos desativado o do leito intermediÃrio sendo estabelecida a seguinte ordem de atividade catalÃtica residual: R1L3 (meio) > R1L2 (topo)  R2L2 (fundo). Os resultados de teor e caracterÃsticas do coque, contaminantes e propriedades texturais sugerem que mecanismos distintos tenham causado a desativaÃÃo desses catalisadores: deposiÃÃo de metais e deposiÃÃo de coque. Os mecanismos de desativaÃÃo foram fortemente influenciados pelo posicionamento das amostras no interior do leito catalÃtico. No inÃcio do leito, a contaminaÃÃo por metais (notadamente Si e As) revelou-se o principal mecanismo de desativaÃÃo. Jà no final do leito, a deposiÃÃo de coque foi o mecanismo preponderante e a temperatura de reaÃÃo identificada como a principal causa para o maior envelhecimento do coque. / The main objective of this work is to study the residual catalyst activity and the mechanisms of deactivation of catalyst from a lube-oil hydroprocessing industrial unit. In order to accomplish this, pilot plant tests were carried out followed by spent catalysts characterization. The residual catalytic activity was determined by HDA, HDS and HDN conversions and adjusted by a power law apparent kinetic model. Pilot plant tests revealed different levels of residual activity for spent catalyst samples. Catalyst samples taken from the first and last of the five catalytic beds showed higher deactivation than others. Catalyst characterization results pointed out two mechanisms as the main reason for the catalytic deactivation through the industrial reactor: poisoning by metal deposition (mainly Si and As) and coke deposition. Poisoning was the main deactivation mechanism for the first bed spent catalyst sample, while coke deposition was predominant at the last catalytic bed sample. Reactor temperature was identified as the most important operational parameter considering coke aging.

The control of particle emissions from an oil refinery is often difficult, due to changing operational conditions and the limited range of available treatment options. Excessive particle emissions have often been attributed start up problems with Fluidized Catalytic Cracker Units (FCCU) and little information is available regarding the exact composition and nature of these excessive emissions. Due to the complex nature of a FCCU, it has in the past been difficult to identify and control emissions, without the use of expensive end of pipe technologies. An Australian Oil Refinery, concerned with their catalyst emissions, sponsored this study of FCCU particle emissions. Due to the industrial nature of the project, a holistic approach to the management of emissions was taken, instead of a detailed investigation of a single issue. By looking at the broader range of issues, practical and useful outcomes can be achieved for the refinery. Initially, detailed emissions samplings were conducted to investigate the degree of particle emissions under start up conditions. Stack emissions were collected during a standard start up, and analysed to determine the particle size distribution and metal concentration of the emitted material. Three distinct stages of emissions were discovered, initially a high concentration of larger particles, followed by a peak in the very fine particles and finally a reduction of particle emissions to a more steady or normal operational state. The variation in particle emissions was caused by operational conditions, hardware design and catalyst characteristics. Fluctuations in the gas velocity through the system altered the ability of the cyclones to collect catalyst material. Also, the low bed level allowed air bypass to occur more readily, contributing to the increased emissions levels seen during the initial stage of the start up. Reduced fluidity characteristics of the circulating catalyst also affected the diplegs operations, altering the collection efficiency of the cyclone. During the loading of catalyst into the system, abraded material was quickly lost due to its particle size, contributing to fine particle emissions levels. More importantly, thermal fracturing of catalyst particles occurred when the cold catalyst was fed into the hot regenerator. Catalyst particles split causing the generation of large amounts of fine particle material, which is easily lost from the system. This loading of catalyst directly linked to the period of high concentration of fine particles in the emissions stream. It was found that metals, and in particular iron, calcium and silicon form a thick layer on the outside of the catalyst, with large irregular shaped metal ridges, forming along the surface of the particle. These ridges reduce the fluidity of the catalyst, leading to potential disruptions in the regenerator. In addition to this, the metal rich ridges are preferentially removed via attrition, causing metal rich material to be emitted into the atmosphere. To overcome these high particle emissions rates from the FCCU the refinery should only use calcinated catalyst to reduce the influence of thermal process and particle fracture and generation. Although the calcinated catalyst can fracture when added to the system, it is far less than that obtained with uncalicinated catalyst. To further reduce the risk of particle fracture due to thermal stresses the refinery should consider reducing the temperature gradients between the hot and cold catalyst. Due to the economics involved with the regenerator, possible pre-warming of catalyst before addition into system is the preferred option. This pre-heating of catalyst should also incorporate a controlled attrition stage to help remove the build up of metals on the surface of the particles whilst allowing this material to be collected before it can be released into the atmosphere. The remove of the metal crust will also improve the fluidity of the system and reduce the chance of catalyst blockages occurring. Finally, modelling of the system has shown that control of key parameters such as particle size and gas velocity are essential to the management of air emissions. The refinery should look at adjusting start up procedures to remove fluctuations in these key parameters. Also the refinery should be careful in using correlation found in the literature to predicted operational conditions in the system as these correlations are misleading when used under industrial situations.

This thesis concerns catalytic combustion for gas turbineapplication using a low heating-value (LHV) gas, derived fromgasified waste. The main research in catalytic combustionfocuses on methane as fuel, but an increasing interest isdirected towards catalytic combustion of LHV fuels. This thesisshows that it is possible to catalytically combust a LHV gasand to oxidize fuel-bound nitrogen (NH3) directly into N2without forming NOX. The first part of the thesis gives abackground to the system. It defines waste, shortly describesgasification and more thoroughly catalytic combustion. The second part of the present thesis, paper I, concerns thedevelopment and testing of potential catalysts for catalyticcombustion of LHV gases. The objective of this work was toinvestigate the possibility to use a stable metal oxide insteadof noble metals as ignition catalyst and at the same timereduce the formation of NOX. In paper II pilot-scale tests werecarried out to prove the potential of catalytic combustionusing real gasified waste and to compare with the resultsobtained in laboratory scale using a synthetic gas simulatinggasified waste. In paper III, selective catalytic oxidation fordecreasing the NOX formation from fuel-bound nitrogen wasexamined using two different approaches: fuel-lean andfuel-rich conditions. Finally, the last part of the thesis deals with deactivationof catalysts. The various deactivation processes which mayaffect high-temperature catalytic combustion are reviewed inpaper IV. In paper V the poisoning effect of low amounts ofsulfur was studied; various metal oxides as well as supportedpalladium and platinum catalysts were used as catalysts forcombustion of a synthetic gas. In conclusion, with the results obtained in this thesis itwould be possible to compose a working catalytic system for gasturbine application using a LHV gas. <b>Keywords:</b>Catalytic combustion; Gasified waste; LHVfuel; RDF; Biomass; Selective catalytic oxidation; NH3; NOX;Palladium; Platinum; Hexaaluminate; Garnet; Spinel;Deactivation; Sulfur; Poisoning

<p>This thesis concerns catalytic combustion for gas turbineapplication using a low heating-value (LHV) gas, derived fromgasified waste. The main research in catalytic combustionfocuses on methane as fuel, but an increasing interest isdirected towards catalytic combustion of LHV fuels. This thesisshows that it is possible to catalytically combust a LHV gasand to oxidize fuel-bound nitrogen (NH3) directly into N2without forming NOX. The first part of the thesis gives abackground to the system. It defines waste, shortly describesgasification and more thoroughly catalytic combustion.</p><p>The second part of the present thesis, paper I, concerns thedevelopment and testing of potential catalysts for catalyticcombustion of LHV gases. The objective of this work was toinvestigate the possibility to use a stable metal oxide insteadof noble metals as ignition catalyst and at the same timereduce the formation of NOX. In paper II pilot-scale tests werecarried out to prove the potential of catalytic combustionusing real gasified waste and to compare with the resultsobtained in laboratory scale using a synthetic gas simulatinggasified waste. In paper III, selective catalytic oxidation fordecreasing the NOX formation from fuel-bound nitrogen wasexamined using two different approaches: fuel-lean andfuel-rich conditions.</p><p>Finally, the last part of the thesis deals with deactivationof catalysts. The various deactivation processes which mayaffect high-temperature catalytic combustion are reviewed inpaper IV. In paper V the poisoning effect of low amounts ofsulfur was studied; various metal oxides as well as supportedpalladium and platinum catalysts were used as catalysts forcombustion of a synthetic gas.</p><p>In conclusion, with the results obtained in this thesis itwould be possible to compose a working catalytic system for gasturbine application using a LHV gas.</p><p><b>Keywords:</b>Catalytic combustion; Gasified waste; LHVfuel; RDF; Biomass; Selective catalytic oxidation; NH3; NOX;Palladium; Platinum; Hexaaluminate; Garnet; Spinel;Deactivation; Sulfur; Poisoning</p>

The current societal needs for fuels and chemical commodities strongly depend on fossil resources. This dependence can lead to economic instabilities, political problems and insecurity of supplies. Moreover, global warming, which is associated with the massive use of fossil resources, is a dramatic “collateral damage” that endangers the future of the planet. Biomass is the main renewable source available today that can, produce various liquid, gaseous and solid products. Due to their lignocellulosic origin are considered CO2 neutral and thus can generate CO2 credits. Biomass processing can meet to the challenge of reducing of fossil resources by producing a liquid feedstock that can lessen the “fossil dependence” and /or meet the increased demand via a rapidly emerging thermochemical technology: pyrolysis. The ultimate goal of this process is to produce liquid with improved properties that could directly be used as liquid fuel, fuel additive and/or feedstock in modern oil refineries and petrochemical complexes. However, the liquids derived from biomass thermal processing are problematic with respect to their handling and end use applications. Thus, alternative routes of advanced liquid feedstock production are needed. Heterogeneous catalysis has long served the oil refining and petrochemical industries to produce a wide range of fuels and products. The combination of biomass pyrolysis and heterogeneous catalysis (by bringing in contact the produced vapours/liquids with suitable catalysts) is a very promising route. In this dissertation, the exploitation of biomass to produce of liquid feedstock via pyrolysis over a multifunctional catalyst and in a steam atmosphere is investigated.  Steam pyrolysis in a fixed bed reactor demonstrated that steam can be considered a reactive agent even at lower temperatures affecting the yields and the composition of all the products. The devolatilisation accelerates and the amount of final volatile matter in the char. Fast pyrolysis in the presence of steam results in improved and controlled thermal decomposition of the biomass; higher liquid yields and slightly deoxygenated liquid products are also obtained. Steam pyrolysis over a bi-metallic Ni-V catalyst can produce liquids of improved quality (lower O content) and also provide routes for selective deoxygenation. However, a decrease in liquid yield was observed. The combination of metal and acid catalysts (Ni-V/HZSM5) shows enhanced deoxygenation activity and increased H preservation in the produced liquid. The final O content in the liquid was 12.83wt% at a zeolite (HZSM5) loading of~75wt%; however, the yield of the obtained liquid was substantially decreased. Moreover, increased coke formation on the catalyst was observed at highest zeolite rate. The increased catalyst space time (τ) results in a lower liquid yield with reduced oxygen (7.79 wt% at τ =2h) and increased aromatic content. The coke deposited per unit mass of catalyst is lower for longer catalyst space times, while the char yield seems to be unaffected. The evaluation of the stability of the hybrid catalyst showed no significant structural defects and activity loss when the catalyst was regenerated at a low temperature (550οC). / Det nuvarande samhällets behov av bränslen och kemiska produkter är starkt knutet till fossila resurser. Detta beroende kan leda till ekonomisk instabilititet, politiska svårigheter och osäker leveranssäkerhet. Dessutom riskeras allvarliga skador i framtiden på grund av global uppvärmning, vilket är relaterat till det ökande och massiva användandet av fossila bränslen.   Biomassa är en förnybar resurs som är tillgänglig idag, möjlig att utnyttja för produktion av diverse flytande, gasformiga och fasta produkter. Dessa produkter, beroende på biogeniskt ursprung, betraktas som koldioxidneutrala och kan därför generera koldioxidkrediter. Processande av biomassa kan möta utmaningen av minskad fossilbränsleanvändning, genom produktion av flytande råvara som kan reducera beroendet och/eller möta ökad efterfrågan, via en snabbt expanderande termokemisk teknik - pyrolys.    Det slutgiltiga målet med en sådan process är att producera en flytande produkt med förbättrade egenskaper som direkt skulle kunna användas som flytande bränslen, bränsleadditiv och/eller som råmaterial i moderna oljeraffinaderier och petrokemiska komplex. Vätskor som utvinns från termiska processer är problematiska med avseende på hantering och slutanvändningen i olika applikationer, därmed behövs olika spår för produktion av avancerade flytande råvaror. Heterogena katalysen har länge tjänat raffinaderi- och petrokemisk industri, som producerar ett brett utbud av bränslen och produkter, lämpliga för säker användning. Kombinationen av biomassapyrolys och heterogen katalys  (genom att bringa pyrolysångorna i kontakt med en lämplig katalysator) är ett väldigt lovande spår. I denna avhandling undersöks användningen av biomassa för produktion av flytande råvara, via pyrolys över en flerfunktionel katalysator i ångatmosfär. Ångpyrolys i en fastbäddsreaktor visade att ånga kan betraktas som ett reaktivt medium,  även vid låga temperaturer, som påverkar utbyten och sammansättning av alla produkter. Avgasningen sker snabbare och den slutliga flykthalten i kolresterna blir lägren vid användning av ånga. Snabbpyrolys i ångatmosfär resulterar i förbättrad och mer kontrollerad termisk nedbrytning av biomassa, vilket ger ett högre vätskeutbyte och en något deoxygenerad flytande produkten. ångpyrolys i kombination med bimetalliska NiV-katalysatorer, ger upphov till en flytande råvara med förbättrad kvalitet och selektiv deoxygenering. Dock med ett minskande utbyte som följd. Kombinationen av metall och en sur katalysator (Ni-V/HZSM5) visade förstärkt deoxygenering med bibehållen vätehalt i den flytande produkten. Den slutliga syrehalten i vätskan var 12.83 vikt% vid en zeolithalt (HZSM5) på 75 vikt%, dock med ett kraftigt minskande vätskeutbyte. Dessutom noterades ökad koksbildning på katalysatormaterialet med den högsta zeolithalten. Ökad rymd-tid  för katalysatorn (τ) ger ett lägre vätskeutbyte med reducerad syrehalt (7.79 vikt% vid τ=2h) och ökad aromathalt. Koksbildning på ytan, per massenhet katalysatormaterial, minskade vid längre rymd-tider medan utbytet av kolrester förblev opåverkat.  Undersökningen av stabiliteten hos hybridkatalysatorn visade inga strukturella defekter och ingen signifikant minskad aktivitet efter regenerering vid låg temperatur (550οC). / Οι σύγχρονες ανάγκες της κοινωνίας για παραγωγή υγρών καυσίμων και χημικών προϊόντων εξαρτώνται από τους ορυκτούς πόρους. Αυτή η εξάρτηση μπορεί να οδηγήσει σε οικονομικά προβλήματα, πολιτκή αστάθεια, όπως επίσης και αβεβαιότητα στις προμήθειες της ενεργειακής εφοδιαστικής αλυσίδας. Επιπροσθέτως, μια δραματική «παράπλευρη απώλεια» η οποία θέτει σε κίνδυνο το μέλλον του πλανήτη είναι η υπερθέρμανσή του, η οποία έχει συσχετισθεί με την εκτεταμένη χρήση ορυκτών πόρων. Σήμερα, η βιομάζα είναι η μόνη ανανεώσιμη πηγή από την οποία μπορούν να παραχθούν υγρά, αέρια και στερεά προϊόντα, που λόγω της λιγνοκυταρρινικής τους προελεύσεως, η συνεισφορά τους στις εκομπές CO2 θεώρειται μηδενική. Η θερμοχημική επεξεργασία της βιομάζας συνεισφέρει στον περιορισμό της χρήσης ορυκτών πόρων, με την παραγωγή υγρών προϊόντων, τα οποία μπορούν να μειώσουν την εξάρτηση ή /και την αυξημένη ζήτηση μέσω μιας ταχέως αναπτυσόμενης τεχνολογίας, της πυρόλυσης. Στόχος της διεργασίας είναι η παραγωγή υγρών προϊόντων με ιδιότητες, που επιτρέπουν την απευθείας χρήση τους ως υγρά καύσιμα ή ως πρώτη ύλη, για την παραγώγη χημικών προϊόντων σε συγχρονες μονάδες διύλισης πετρελαίου και σε πετροχημικά συγκτροτήματα. Εν τούτοις, τα υγρά προϊόντα της θερμικής διάσπασης (πυρόλυση) είναι προβληματικά στη διαχείρηση και στις τελικές τους εφαρμογές, λόγω της σύστασής τους. Ως εκ τούτου, απαιτούνται νέες τεχνικές για παραγωγή προηγμένων υγρών προοϊόντων. Η ετερογενής κατάλυση έχει επιτυχώς εφαρμοσθεί στην πετρελαϊκή και χημική βιομηχανία, παράγοντας ένα μεγάλο εύρος προϊόντων. Ο συνδυασμός της με την πυρόλυση (φέρνοντας σε επαφη τα υγρά/ατμούς με κατάλληλο καταλύτη) αποτελεί μια πολλά υποσχόμενη ενναλακτική. Στην παρούσα διατριβή μελετάται η αξιοποίηση βιομάζας για παραγωγή υγρών προϊόντων μέσω καταλυτικής πυρόλυσης, με χρήση πολυλειτουρικού καταλύτη (multi-functional catalyst) υπό την παρουσία ατμού. Η χρήση ατμου κατά τη διαρκειά πυρόλυσης βιομαζας σε αντιδραστήρα σταθερής κλίνης, μεταβάλει τη σύσταση των επιμέρους προϊόντων. Η παρουσία ατμού έχει ως αποτέλεσμα την ταχύτερη αποπτητικοποίηση του υλικού, ενώ παράλληλα η περιεκτικότητα του υπολειπόμενου εξανθρακώματος σε πτητικά είναι μικρότερη. Τα πειραματικά αποτελέσματα ταχείας πυρόλυσης σε αντιδραστήρα ρευστοστερεάς κλίνης δείχνουν ό,τι η χρήση ατμού βελτιώνει την θερμική διάσπαση της βιομαζας, αυξάνοντας την απόδοση σε υγρά προϊοντά, ενώ παράλληλα βοηθάει στην αποξυγόνωσή τους. Ο συνδυασμός της πυρόλυσης υπό την παρουσία ατμού και διμεταλλικού καταλύτη νικελίου–βαναδίου μπορεί να  βελτιώσει την ποιότητα των παραγόμενων υγρών (αποξυγόνωση) με παραλλήλη μείωση της απόδοσής τους, ενώ μπορεί να  παράγει προϊόντα εκλεκτικής αποξυγόνωσης. Συνδυασμός μεταλλικών και ζεολιθικών καταλυτών (Ni-V/HZSM5) εμφανίζει βελτιωμένη δραστικότητα στις αντιδράσεις αποξυγόνωσης, με παράλληλη συγκράτηση υδρογόνου (Η) στα υγρά προϊόντα. Η τελική περιεκτικότητα των υγρών προϊόντων σε οξυγόνου (Ο) μετά από 90 min αντίδρασης είναι 12.83 wt%, με περιεκτικότητα ζεόλιθου (ΗZSΜ5) ~75 wt% στον καταλύτη. Ωστόσο, η αυξηση της περεικτικότητας σε ζεόλιθο έχει ως αποτέλεσμα την αύξηση των επικαθήσεων άνθρακα επάνω στον κατάλυτη, καθώς και την σημαντική μειώση της απόδοσης των υγρών προϊόντων (24.35wt% επι ξηρής βιομάζας).  Η αύξηση του χώρου χρόνου του καταλύτη (τ) έχει ως αποτέλεσμα: τη μείωση των υγρών προϊόντων, τη μείωση του περιεχόμενου Ο στα υγρά προϊόντα (7.79 wt% at τ =2h), την αύξηση των αρωματικών υδρογονανθράκων και τη μείωση του επικαθήμενου κωκ ανά μονάδα μάζας καταλύτη. Η απόδοση του εξανθρακώματος παρέμεινε πρακτικά αμετάβλητη. Η αναγέννηση του υβριδικού καταλύτη σε χαμηλές θερμοκρασιές (550οC) δεν επέφερε σημαντικές δομικές αλλαγές και απώλεια δραστικότητας. / <p>QC 20140306</p>

Este trabalho de pesquisa visa estudar o processo de formação das emissões gasosas num motor de combustão interna movido à álcool e analisar os fatores que contribuem para o controle dessas emissões em níveis estabelecidos pela legislação. Especial atenção foi dada à aplicação de conversores catalíticos platina/paládio como auxiliar no processo de controle das emissões gasosas automotivas. Foram realizados ensaios dinanométricos de um motor de combustão interna para analisar as emissões e o controle destas, em condições operacionais, em função da razão ar-combustível, ponto de ignição e rotação. O conversor catalítico contribuiu para redução de mais de 80% das emissões gasosas danosas à saúde, quando o motor operava em condições estequiométricas. Observou-se a necessidade de desenvolver o sistema de admissão e descarga do motor para receber o catalisador sem que este cause redução considerável à queda da eficiência volumétrica do motor. / This work of research aim analyzes process of formation of gas emissions in alcohol internal combustion engines and analyses factors that contribute to control those emissions in level established by legislation. Special attention was faced application of catalytic converters platin/palladium with auxiliary in the process of control emissions gas automotives. Assays dynamometric were realized of to analyses emission and control them, in conditions operation ales, in function of air-fuel ratio, point of ignition and rotation the catalytic converters contribute to reduction more of 80% of emissions gas that cause damage health, when observed that necessity of develop system of admission and exhaust of engines to receive catalysts out that provocate reduction considerable decrease of efficiency volumetric of engines.

Abstract The large amounts of industrial wastewaters, contaminated by hazardous and toxic compounds together with ever tightening legislation, have challenged traditional wastewater treatment methods. Therefore, the development of discharge limits under, cost-effective and ecological wastewater treatment has become an essential concern. Catalytic water phase technologies are interesting alternatives for traditional wastewater treatment. Among them catalytic wet air oxidation (CWAO) has been used successfully in the management of various industrial effluents. However, the development of an active and stable catalyst for the severe reaction conditions of CWAO has proved truly challenging. The aim of this thesis was to study the activity and stability of laboratory prepared cerium supported metal catalysts in the catalytic wet air and wet peroxide oxidation of aqueous organic pollutants. Ru supported on Ce-Zr mixed oxides and commercial activated carbon as reference were used in CWAO and catalytic wet peroxide oxidation (CWPO) of surface plating industry wastewater. Ag/Ce-Zr and Pt/Ce-Ti catalysts were catalyzed CWAO of aqueous solution of bisphenol A (BPA). Both CWAO and CWPO improved the abatement of organic compounds from surface plating industry wastewater when comparing the non-catalytic experiments. Moreover, catalytic oxidation enhanced the biodegradability of organic matter in the wastewaters. According to the results, Pt/Ce-Ti catalysts performed with higher activity in CWAO of BPA than Ag/Ce-Zr catalysts and almost 100% removal of BPA was achieved. The leaching of active metal during oxidation experiments affected the activity of Ag/Ce-Zr catalysts. Moreover, CWAO of BPA was not a surface area specific reaction but the activity of catalysts was related to the chemisorbed oxygen content on the catalysts’ surface. The results of this thesis showed that cerium supported metal catalysts are active and stable catalysts in CWAO of BPA and also in the treatment of industrial wastewater. Therefore, these catalysts could be applied next to pilot scale applications. / Tiivistelmä Teollisuuden jätevedet sisältävät usein haitallisia ja myrkyllisiä yhdisteitä, joiden käsittely perinteisillä jäteveden käsittelymenetelmillä on hyvin haastavaa. Lisäksi alati kiristyvä ympäristölainsäädäntö asettaa omat vaatimuksensa jäteveden käsittelylle. Katalyyttiset vedenkäsittelymenetelmät ovat viime vuosina herättäneet paljon kiinnostusta. Yksi lupaavimmista tekniikoista on katalyyttinen märkähapetus, jota on käytetty sekä lukuisten malliaineiden että teollisten jätevesien käsittelyssä. Märkähapetuksen vaativissa reaktio-olosuhteissa aktiivisena säilyvän katalyyttimateriaalin kehittäminen on kuitenkin osoittautunut varsin haasteelliseksi. Väitöskirjatutkimuksen tavoitteena oli kehittää aktiivisia ja kestäviä ceriumpohjaisia katalyyttimateriaaleja märkähapetusreaktioon. Tutkimuksessa valmistettiin Ru-, Pt- ja Ag-katalyyttejä, jotka impregnoitiin Ce-Zr- ja Ce-Ti-sekaoksideille. Ru/Ce-Zr-katalyyttejä sekä kaupallista aktiivihiiltä vertailumateriaalina käytettiin pintakäsittelyteollisuuden jäteveden märkähapetuksessa ja märkäperoksidihapetuksessa. Bisfenoli A:n (BPA) vesiliuoksen märkähapetusta katalysoitiin sekä Ag/Ce-Zr- että Pt/Ce-Ti-katalyyteillä. Katalyyttisellä märkähapetuksella ja märkäperoksidihapetuksella pintakäsittelyteollisuuden jäteveden orgaanisten yhdisteiden konsentraatio väheni enemmän verrattuna ilman katalyyttiä suoritettuihin hapetuksiin. Lisäksi käsitellyn vesinäytteen biohajoavuusaste nousi eli jäteveden sisältämät orgaaniset yhdisteet olivat hapettuneet helpommin biohajoavaan muotoon. Pt/Ce-Ti-katalyytit olivat Ag/Ce-Zr-katalyyttejä aktiivisempia BPA:n märkähapetusreaktiossa. Pt-katalyyttisessä reaktiossa saavutettiin lähes 100 % reduktio BPA:n pitoisuudessa. Ag-katalyyttien aktiivisuuteen vaikutti hopean osittainen liukeneminen hapetettavaan liuokseen märkähapetusreaktion aikana. Lisäksi havaittiin, että BPA:n märkähapetusreaktiossa katalyytin aktiivisuus oli riippuvainen katalyyttipintaan kemiallisesti sitoutuneen hapen määrästä eikä niinkään katalyytin pinta-alasta. Väitöskirjatutkimuksessa saatujen tulosten perusteella valmistetut ceriumpohjaiset metallikatalyytit olivat aktiivisia ja kestäviä. Katalysoiduissa hapetusreaktiossa sekä BPA:n että pintakäsittelyteollisuuden jäteveden orgaaninen kuormitus pieneni. Siksi valmistettuja katalyyttimateriaaleja voitaisiin tutkia seuraavaksi pilotti-mittakaavan sovellutuksissa.

Treatment of fuel cell feed H2 for the removal of CO is important owing to the poisoning of the catalysts, thereby affecting the performance of the fuel cell. Strong and preferential adsorption of CO over the catalyst takes place resulting in a reduction of the power output of the cell. Therefore, it is important to treat the fuel cell feed H2 to reduce its CO content below the tolerable limit. Development of efficient catalysts for the treatment of synthesis gas for the removal of CO and and H2 enrichment of the gas to make it suitable for fuel cells is one of the two goals of this thesis. One of the various possible strategies for the removal of CO from the synthesis gas can be the use of the water-gas shift reaction. We have developed noble metal substituted ionic catalysts for catalyzing the water-gas shift reaction and have studied in detail the kinetics of the reactions by proposing the relevant reaction mechanisms. Solution combustion, a novel technique for synthesizing nanocrystalline materials, was used for the synthesis of all the catalysts. All the compounds synthesized were solid solutions of the noble metal ion and transition or rare earth metal oxide support. Three different supports were used, viz., CeO2, ZrO2 and TiO2. Substitution of Zr and Ti in CeO2 up to 15 at% was also carried out to obtain the compounds with enhanced oxygen storage capacity. All the compounds were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy. In some cases, where it was required, the use of FT-Raman spectroscopy was made for structural analysis. The compounds were nanocrystalline with metals substituted in ionic form in the support. The water-gas shift reaction was carried out over the synthesized catalysts with a reactant gas mixture that simulated the actual refinery gas composition. The variation of CO concentration with temperature was traced. The changes in the oxidation state of the metal showed the involvement of the various redox pairs over the reducible oxide like substituted CeO2 and TiO2. The mechanism of the reaction over ZrO2-based compounds was found to take place utilizing the surface hydroxyl groups. Rate expressions for the reactions over all the catalysts following different mechanisms were derived from the proposed elementary processes. Nonlinear regression was used for the estimation of various parameters describing the rate of reaction. Having established the high activity of Pt-ion substituted TiO 2 for the reactions, steam reforming of wood gas obtained from the gasification of Casuarina wood chips was carried out. The enrichment of the gas stream, which initially consisted of nearly 10% H 2 was carried out by steam reforming and H2-rich stream was obtained with H2 as high as 40% by volume in the treated gas. The second motive behind this thesis was to test the activity of the noble-metal substituted ionic catalysts for the treatment of the exhaust gas coming out of a fuel cell. In the fuel cell utilizing H2, the exhaust gases contain certain amount of unreacted H2, which can not be recovered or utilized economically. However, the gases are combustible and H 2 has to be removed in order to make the gas clean. We have shown high activity of the combustion-synthesized ionic compounds for catalytic combustion of H2. All the compounds showed high activity for H2 combustion and complete removal of H2 was possible. The rates were found to increase with an decrease in H2:O2 ratio and complete conversion of H2 was possible within 100 oC with air. A mathematical model was developed for the kinetics of catalytic H2 combustion based on the elementary processes that were proposed using the spectroscopic evidences. CO tolerant capacity of the catalysts was also tested. It was found that the temperature requirement for most of the catalysts increased with the introduction of CO. However, it was still possible to obtain complete conversions within 200 oC. To summarize, fuel cell processing systems utilizing H 2 remained central to the study. Treatment of the gases, both before and after reaction from the fuel cell was carried out over noble metal-substituted ionic catalyst, synthesized by solution combustion technique. Mechanisms of the reactions were proposed on the basis of spectroscopic evidences and the kinetic rate parameters were estimated using non-linear regression.