La grande majorité des résines époxy utilisées aujourd’hui sont issues ou dérivées du bisphénol-A (BPA). Cependant, le BPA est soumis à de très fortes régulations, notamment vis-à-vis de sa récente classification comme substance chimique extrêmement préoccupante par l’agence européenne des produits chimiques (ECHA). Dans un but d’anticiper les évolutions de régulation, ArianeGroup a décidé de remplacer cette substance chimique de ces formulations. Ces travaux de thèse portent donc sur l’élaboration de nouvelles résines époxy biosourcées ayant des propriétés similaires voire supérieures aux références dérivées du bisphénol-A. Pour cela, une bioplatforme de monomères polyépoxydés issus de la vanilline, du méthyl vanillate, du 2,6-diméthoxyphénol et de l’eugénol a été développée. Ces précurseurs biosourcés ont ensuite été utilisés comme précurseurs de réseaux époxyde par réticulation avec des amines. Les réseaux réticulés biosourcés ainsi obtenus ont démontré des propriétés thermomécaniques remarquables bien supérieures à la référence de type DGEBA, notamment en termes de température de transition vitreuse (>300 °C) et taux de coke (>50%). En parallèle de ces travaux, la synthèse de diamines biosourcées, dérivées de la divanilline, et pouvant être utilisées comme agents de réticulation de résines époxy, a été réalisée. Des réseaux époxyde entièrement biosourcés ont ainsi été synthétisés et présentent des propriétés thermomécaniques prometteuses. / Today, most of the epoxy resins produced are derived from bisphenol-A (BPA). However, BPA is subject to strong regulations, particularly because of its recent classification as chemical of very high concern by the European Chemicals Agency (ECHA). In order to anticipate new regulations, ArianeGroup has decided to replace this substance in its applications. The aim of this thesis is to develop new bio-based epoxy thermosets with comparable thermomechanical properties as the ones issued from bisphenol-A-based materials. For this purpose, a bio-platform of epoxy monomers from vanillin, methyl vanillate, 2,6-dimethoxyphenol and eugenol was developed. These precursors were cross-linked with amines used as curing agent to obtain bio-based epoxy networks. The latter demonstrated thermomechanical properties well above the DGEBA-type reference, especially in terms of glass transition temperature (> 300 °C) and char content (> 50%). Finally, the synthesis of bio-based diamines derived from divanillin was developed and enabled the synthesis of fully bio-based epoxy networks with promising thermomechanical properties.

A produção de energia é um dos grandes desafios deste século, principalmente com a necessidade no desenvolvimento de processos que utilizem preferencialmente fontes renováveis. Nesse contexto, é claro o interesse por pesquisas baseada no hidrogênio. Porém, os ganhos ambientais efetivos estão associados também à matéria-prima usada no processo de geração do hidrogênio, senso assim mais significativo quando do uso de fontes renováveis. No presente trabalho foi estudado o efeito da adição de diferentes teores de CeO2 em catalisadores de NiZnO, preparados pelo método da co-precipitação. Os catalisadores foram estudados frente à reação de reforma a vapor do etanol (RVE) para produção de H2, e no decorrer do trabalho foi pertinente incluir o estudo da reforma a vapor da acetona (RVA), como complemento dos estudos da RVE. Além disso, esta é uma molécula modelo para reforma a vapor do bio-óleo. Nos sistemas catalíticos sintetizados houve a formação da liga NiZn3, o que aparenta proporcionar um efeito sinérgico entre esses elementos. Observou-se um efeito altamente promotor do CeO2 com relação a diminuição do coque formado, devido a uma menor da formação da acetona, durante as etapas de reforma do etanol. O que consequentemente interferiu na produção de H2. O catalisador contendo 20% de CeO2 denominado NiZn20Ce apresentou um desempenho altamente promissor, pois de acordo com as análises de DRIFT, a presença do CeO2 levou a formação de espécies de formiato, o que consequentemente interferiu em uma menor formação de coque e maior produção de H2. Foi comprovado também que a natureza dos depósitos carbonáceos depende tanto do substrato utilizado quanto das etapas precursoras inicias que levarão a formação desse coque, sendo o ponto chave para um melhor desempenho do catalisador. / Energy production is one of the great challenges of this century, especially with the need to develop processes that use preferentially renewable sources. In this context, it´s evident the interest in research based on hydrogen. However, the environmental benefits are also associated with the raw material used on the hydrogen generation process, being more significant when used renewable sources. In the present work, it was studied the effect of CeO2 addition in NiZnO catalysts, prepared by coprecipitation method. The catalysts were studied front of the ethanol steam reforming reaction (ESR) to produce H2, and in the course of this study was relevant include study of acetone steam reforming (ASR), as a complement of ESR studies. Moreover, acetone is a molecule model for steam reforming of bio-oil. In the catalyst systems there has been the NiZn3 alloy formation, which provides a synergistic effect between these elements. It was observed a high CeO2 promoter effect regarding reduction of the formed coke, due to lower formation of acetone in the ethanol reforming steps, and consequently interfere in the H2 production. The catalyst denominated NiZn20Ce showed a high performance, according to DRIFT analyzes, the presence of the CeO2 led to the formation of species formate, which in turn interfere through a lower coke formation and higher H2 production. It was also established that the nature of the carbonaceous deposits depends as the substrate used as the precursors initial steps that led the formation of this coke, and it is the key to a better performance of the catalyst.

Abstract When producing ferrochrome, a submerged arc furnace (SAF) is used. The charge of an SAF consists of chromite pellets, coke, lumpy ore and quartzite as a slag modifier. The charge is pre-heated before it descends into the SAF where the charge eventually reduces and melts. The electrical conductivity of the charge is important because, among other things, it affects the productivity of the furnace. The electrical conductivity of the charge should ideally be low on the higher parts of the furnace and high near the electrode tip. This is to ensure that the electric current path travels through the metal bath via arcing, which provides the most effective heat transfer. Another option for the current path would be through the solid feed material via ohmic conduction, but since this zone is less reactive, the heat energy would be mostly wasted. This work brings forth new information about the electrical behaviour of coke and chromite pellet is produced. The electrical conductivity was measured at room temperature for different simulated process conditions (different coke textures, different reduction degrees of chromite pellets, sulphur in atmosphere and replacing the coke used in chromite pellet production with charcoal). It was found out that unlike gasification with a CO/CO2 mixture, heat treatment at 950°C increased the degree of graphitization and changed the electrical behaviour of coke. Furthermore, it was observed that increasing the chromite pellets’ reduction degree reduced the electrical conductivity measured at room temperature. In the case of chromite pellets and sulphur in the atmosphere it was found that sulphur has an effect on the pellets’ electrical behavior and structure during reduction, which - in turn - has an effect on the SAF performance when raw materials with varying sulphur contents are used. Lastly, it was found that substituting coke with charcoal when producing chromite pellets affects the sintering behaviour, cold compression strength, and electrical conductivity of the chromite pellets. / Tiivistelmä Uppokaariuuni on osa ferrokromin valmistusprosessia. Uppokaariuuniin panostetaan kromiittipellejä, koksia, palarikastetta ja kvartsiittia. Etukuumennusuunista panos laskeutuu uppokaariuuniin, jossa se pelkistyy ja lopulta sulaa. Uppokaariuunin panoksen sähkönjohtavuus on tärkeää uunin toiminnan kannalta, koska se vaikuttaa suoraan esimerkiksi tuottavuuteen. Jotta virran kulku tapahtuisi optimaalisesti sulan metallin kautta, panoksen sähkönjohtavuuden tulee olla pieni uunin yläosissa ja suuri alaosassa lähellä elektrodien päitä. Mikäli virran kulku tapahtuu uunin yläosassa, hukataan lämpöenergiaa ja uunin toiminta hankaloituu. Tässä työssä on selvitetty koksin ja kromiittipellettien sähköisiä ominaisuuksia. Sähkönjohtavuutta on tutkittu useilla simuloiduilla prosessiolosuhteilla (koksin eri tekstuurit, kromiittipellettien eri pelkistysasteet, rikin pitoisuus atmosfäärissä ja kromiittipellettien valmistuksessa on korvattu koksi puuhiilellä). Nämä mittaukset on tehty huonelämpötilassa. Huomattiin, että toisin kuin koksin kaasutus, koksin lämpökäsittely (950°C) nosti grafitoitumisastetta ja vaikutti sähköisiin ominaisuuksiin. Kromiittipelletin pelkistymisasteen noustessa huonelämpötilassa mitattu sähkönjohtavuus laski. Kun kromiittipelletit altistetaan atmosfäärille, jossa on rikkiä, pellettien sähköiset ominaisuudet muuttuvat samoin kuin rakenne pelkistyksen aikana. Tämä vaikuttaa uppokaariuunin toimintaan, kun käytetään raaka-aineita, joissa rikkipitoisuus vaihtelee. Kun kromiittipellettien valmistuksessa käytettävä koksi korvataan puuhiilellä, tämä vaikuttaa sintrausprosessiin, kylmälujuuteen ja sähköisiin ominaisuuksiin.

A produção de energia é um dos grandes desafios deste século, principalmente com a necessidade no desenvolvimento de processos que utilizem preferencialmente fontes renováveis. Nesse contexto, é claro o interesse por pesquisas baseada no hidrogênio. Porém, os ganhos ambientais efetivos estão associados também à matéria-prima usada no processo de geração do hidrogênio, senso assim mais significativo quando do uso de fontes renováveis. No presente trabalho foi estudado o efeito da adição de diferentes teores de CeO2 em catalisadores de NiZnO, preparados pelo método da co-precipitação. Os catalisadores foram estudados frente à reação de reforma a vapor do etanol (RVE) para produção de H2, e no decorrer do trabalho foi pertinente incluir o estudo da reforma a vapor da acetona (RVA), como complemento dos estudos da RVE. Além disso, esta é uma molécula modelo para reforma a vapor do bio-óleo. Nos sistemas catalíticos sintetizados houve a formação da liga NiZn3, o que aparenta proporcionar um efeito sinérgico entre esses elementos. Observou-se um efeito altamente promotor do CeO2 com relação a diminuição do coque formado, devido a uma menor da formação da acetona, durante as etapas de reforma do etanol. O que consequentemente interferiu na produção de H2. O catalisador contendo 20% de CeO2 denominado NiZn20Ce apresentou um desempenho altamente promissor, pois de acordo com as análises de DRIFT, a presença do CeO2 levou a formação de espécies de formiato, o que consequentemente interferiu em uma menor formação de coque e maior produção de H2. Foi comprovado também que a natureza dos depósitos carbonáceos depende tanto do substrato utilizado quanto das etapas precursoras inicias que levarão a formação desse coque, sendo o ponto chave para um melhor desempenho do catalisador. / Energy production is one of the great challenges of this century, especially with the need to develop processes that use preferentially renewable sources. In this context, it´s evident the interest in research based on hydrogen. However, the environmental benefits are also associated with the raw material used on the hydrogen generation process, being more significant when used renewable sources. In the present work, it was studied the effect of CeO2 addition in NiZnO catalysts, prepared by coprecipitation method. The catalysts were studied front of the ethanol steam reforming reaction (ESR) to produce H2, and in the course of this study was relevant include study of acetone steam reforming (ASR), as a complement of ESR studies. Moreover, acetone is a molecule model for steam reforming of bio-oil. In the catalyst systems there has been the NiZn3 alloy formation, which provides a synergistic effect between these elements. It was observed a high CeO2 promoter effect regarding reduction of the formed coke, due to lower formation of acetone in the ethanol reforming steps, and consequently interfere in the H2 production. The catalyst denominated NiZn20Ce showed a high performance, according to DRIFT analyzes, the presence of the CeO2 led to the formation of species formate, which in turn interfere through a lower coke formation and higher H2 production. It was also established that the nature of the carbonaceous deposits depends as the substrate used as the precursors initial steps that led the formation of this coke, and it is the key to a better performance of the catalyst.

Orientadores: José Roberto Nunhez, Everton Moraes Matos / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-21T22:56:39Z (GMT). No. of bitstreams: 1 Fontoura_DienerVolpinRibeiro_D.pdf: 11658919 bytes, checksum: 6a2be1fd48301240f5f4b18c84757db1 (MD5) Previous issue date: 2013 / Resumo: O escoamento de fluidos é, sem dúvida, de grande importância na indústria, especialmente no transporte de fluidos entre as unidades de operação. Sistemas multifásicos são bastante comuns, e em muitos casos, também ocorrem processos de transferência de massa e energia, como é o caso dos fornos de pré-aquecimento na indústria petroquímica. O escoamento gás-líquido nessas linhas é muitas vezes complexos, pois durante a vaporização da carga ocorre também o craqueamento térmico do petróleo. É comum nestas operações a formação de coque no interior do tubo, o que é muito indesejável. Para entender as condições nas quais esta formação de coque é minimizada, ou aumentada, foi proposto um modelo uidodinâmico computacional para simular o escoamento bifásico gás - liquido do petróleo no interior desses tubos. O modelo foi implementado na plataforma OpenFOAM, ao qual foram acrescidas novas rotinas para a estimativa das temperaturas e concentrações através das equações de conservação de massa e energia. O modelo k - epsilon foi utilizado para descrever a turbulência e dois modelos de vaporização foram utilizado para caracterizar a mudança de fase. Uma formulação não conservativa foi adotada na escrita das equações do modelo para maior estabilidade numérica em altas frações volumétricas. Foi também implementada uma rede cinética dependente da temperatura para descrever o craqueamento térmico. Através do modelo foi possível simular o escoamento tridimensional de petróleo no interior de um tubo com as dimensões da planta obtendo como resultado os perfis de velocidades, temperaturas e concentrações das fases líquida e gasosa / Abstract: Fluid flow is of great importance in the industry, especially for its transport between the operating units. Multiphase systems are very frequent. In many cases, mass and energy transfer processes, such as the case of preheating furnaces in petrochemical industry, are also observed. The gas-liquid flow in these lines is often complex, because during the vaporization of the charge it also occurs the petroleum thermal cracking. It is common in these operations the very undesirable formation of coke inside the tube. With the aim of understanding under which conditions the formation of coke is minimized or increased it was proposed a computational fluid dynamic model for simulating the petroleum gas-liquid two-phase flow inside of these tubes. The model was implemented on the OpenFOAM software, to which new routines for the calculation of temperatures and concentrations using the equations of conservation of mass and energy were added. The model k - epsilon was used to describe the turbulence and two vaporization models were used to characterize the phase change. A non-conservative formulation was adopted for describing the equations of the model in order to obtain numerical stability at high volumetric fractions. It was also implemented a temperature dependent kinetic net to describe the thermal cracking. With this model it was possible to simulate the three-dimensional flow of petroleum inside a tube with real industrial dimensions as a result of the gas and liquid phase's profiles of velocities, temperatures and concentrations / Doutorado / Desenvolvimento de Processos Químicos / Doutor em Engenharia Química

Abstract The blast furnace – basic oxygen furnace route remains the most utilised process route in the production of steel worldwide. Coke is the main fuel of the blast furnace process, however, coke producers and blast furnace operators are facing significant challenges due to increased demands on coke quality and decrease of prime coking coals. The estimation of coke performance in the industrial process through accurate laboratory analyses is of increasing importance. In this doctoral thesis, the aim was to study phenomena related to coke properties and its analysis methods in blast furnace simulating conditions. A new method was introduced to measure the hot strength of coke using a Gleeble 3800 thermomechanical simulator. The hot strengths of industrial cokes were determined at various temperatures and several coke properties, which were believed to affect hot strength, were determined. The effect of H₂ and H₂O in the blast furnace shaft gas were determined in relation to coke reactivity, threshold temperature, and the gasification mechanism. The results obtained by this thesis show that the Gleeble device is suitable for study of coke hot strength. The coke strength was significantly decreased for all three coke grades at temperatures of 1600 °C and 1750 °C when compared to room temperature or 1000 °C. The deformation behaviour of coke was fragile up to 1000 °C, but became at least partially plastic at 1600 °C, and the plasticity further increased at 1750 °C. Notable changes were observed in the deformation behaviour between coke grades at high temperatures. The presence of H₂ and H₂O in the BF shaft gas strongly increased coke reactivity and changed the reaction mechanism of coke to be more surface centric in a specific temperature range. The reactivity of coke in the conditions 100 vol-% CO₂ did not directly correlate with reactivity in a simulated blast furnace shaft gas, which suggest that the widely utilised CRI test does not accurately estimate coke reactivity in the industrial blast furnace process. / Tiivistelmä Masuuni – konvertteri yhdistelmä on edelleen käytetyin prosessireitti teräksen tuotantoon ympäri maailman. Koksi on masuunin tärkein polttoaine. Koksintuottajat ja masuunioperaattorit ovat suurten haasteiden edessä johtuen koksin kasvaneista laatuvaatimuksista ja parhaiden koksautuvien kivihiilten ehtymisestä. Koksin suoriutumisen arviointi masuunin olosuhteissa tarkoilla laboratorioanalyyseillä on yhä merkittävämmässä roolissa. Tässä väitöskirjassa tavoitteena oli tuottaa uutta tietoa koksin ominaisuuksista ja sen analyysimenetelmistä simuloiduissa masuunin olosuhteissa. Uusi metodi esitettiin koksin kuumalujuuden määrittämiseksi Gleeble 3800 termomekaanisella simulaattorilla. Teollisten koksilaatujen kuumalujuuksia määritettiin eri lämpötiloissa ja useita koksin mitattiin, joilla uskottiin olevan vaikutus kuumalujuuteen. Lisäksi työssä tutkittiin masuunin kuilun kaasuatmosfäärissä H2 ja H2O kaasujen vaikutusta koksin kemialliseen reaktiivisuuteen, kaasuuntumisen kynnyslämpötilaan ja reaktiomekanismiin. Tässä työssä esitetyt tulokset osoittavat että Gleeble soveltuu koksin kuumalujuuden määritykseen. Koksin lujuus aleni merkittävästi kaikilla kolmella koksilaadulla kuumennettaessa 1600 ja 1750 °C lämpötiloihin verrattuna huoneenlämpötilaan tai 1000 °C lämpötilaan. Koksin muodonmuutos oli haurasta aina 1000 °C lämpötilassa, mutta muuttui osittain plastiseksi 1600 °C lämpötilassa ja plastisuus kasvoi kun lämpötilaa nostettiin 1750 °C:een. Huomattavia eroja havaittiin eri koksilaatujen muodonmuutoskäyttäytymisessä korkeissa lämpötiloissa. H₂ ja H₂O kaasujen läsnäolo kuilun kaasuatmosfäärissä kasvatti voimakkaasti koksin reaktiivisuutta ja muutti kaasuuntumismekanismia pintakeskisemmäksi rajatulla lämpötila-alueella. Koksin reaktiivisuus 100 % CO₂ kaasussa ei korreloinut suoraan simuloidun masuunin kuilun kaasuatmosfäärin kanssa. Tämä tulos indikoi sitä että maailmalla yleisesti käytetty CRI testi ei ennusta tarkasti koksin reaktiivisuutta masuunissa.

[pt] O Ácido Húmico (AH) é uma fração orgânica obtida em solos, corpos hídricos bem como em matrizes carbonáceas. Nos últimos anos o interesse associado a esta substância vem crescendo progressivamente à medida que novas aplicações são descobertas, tais como: fertilizantes, recuperação de áreas degradadas e tratamento de efluentes contaminados com metais. As principais características dos AH são dependentes do método de extração e da matriz escolhida, posto que se pode extraí-lo de uma ampla gama de matérias primas, assim como por meio de diferentes métodos. Dentro deste contexto, o objetivo principal do presente trabalho pretende avaliar o potencial de extração de ácido húmico a partir de diferentes precursores carbonáceos. Foram utilizadas três matrizes carbonáceas distintas: rejeito de carvão mineral (RCM), coque mineral (CM) e coque verde de petróleo (CVP). Além deste estudo experimental foram apresentados alguns resultados de estudo semelhante disponível na literatura. O método de extração utilizado foi adaptado de Trompowski et al (2005), e a caracterização foi feita utilizando-se técnicas de ICP-OES, CNHS, MEV/EDS, FTIR e Difração de Raio-X. A eficiência da extração, em termos de recuperação em massa, variou, significativamente, em função do método adotado, sendo os melhores resultados associados ao rejeito de carvão mineral (17,0 porcento), ao passo que a menor eficiência está relacionada ao coque verde de petróleo, após destilação (0,2 porcento). A extração a partir do coque verde de petróleo, como recebido, é inviável em função da sua imiscibilidade com a solução de ácido nítrico. Os resultados obtidos a partir do FTIR foram satisfatórios para todos os AH analisados, apresentando bandas características de AH e compatíveis com o indicado na literatura. Os resultados da análise de ICP-OES apresentaram baixa presença de metais e elementos traços para o AH oriundo do coque mineral. No que diz respeito ao ácido húmico extraído do rejeito de carvão mineral, que apresentou a maior concentração inicial de metais, principalmente ferro, foi implementado, com sucesso, uma purificação utilizando ácido nítrico. Com base nos resultados obtidos é possível afirmar que a utilização de diferente precursores carbonosos permitiu a extração de AH com características semelhantes aqueles citados na literatura e extraídos de outras fontes. / [en] The humic acid (HA) is an organic fraction that can be found in soil and watercourses as well as in carbonaceous matrices. In recent years the interest associated with this substance has been growing steadily as new applications are discovered, such as fertilizers, remediation of degraded areas and treatment of wastewater contaminated with metals. The main features of HA are dependent on the method of extraction and the chosen matrix, since it can be extract from a wide range of raw materials, as well as by different methods. Within this context, the main objective of this work is related to an assessment of the potential of extracting humic acid from different carbonaceous precursors. three different carbonaceous matrices were used: coal tailings (RCM), coke (CM) and green petroleum coke (CVP). Besides this experimental study some results of a similar study available in the literature were presented. The extraction method used was adapted from Trompowski et al, and the characterization was done using ICP- OES techniques, CNHS, MEV / EDS and FTIR. The extraction efficiency, in terms of mass recovery, significantly varied depending on the method used, the best results being associated with coal tailings (17.0 percent), while lower efficiency relates to the calcinated petrocoke after distillation (0.2 percent). The extraction from green petroleum coke, as received, is unfeasible due to its immiscibility with the nitric acid solution. The results obtained from FTIR were satisfactory for all the HA analyzed, displaying bands consistent with those from HA and compatible with bands shown in the literature. The results of the analysis of ICP-OES showed a low presence of metals and trace elements coming from the HA for coke. With respect to the extracted humic acid from coal tailings, which showed the highest initial concentration of metals, particularly iron, was successfully implemented, a purification with nitric acid. Based on the results obtained it can be stated that the use of different carbonaceous precursors allowed the extraction of humic acid with similar characteristics as cited in the literature and those obtained from other sources.

The thesis deals with analysis of calcium carbide production process. The aim of the thesis is to identify and design savings resulting from the use of energy contained in flue gas, which is produced during the process. In the first part, history and applications of calcium carbide are presented. The thesis then contains mass and energy balance of calcium carbide production. Balance is related to 1 ton of the product. In conclusion, possibilities of flue gas use for coke drying are proposed. The thesis is based on the information from the calcium carbide factory located in Sundsvall, Sweden.

Gasification is a process used to convert any carbonaceous species through heterogeneous reaction to obtain the desired gaseous products of H2 and CO which are used to make chemicals, liquid transportation fuels, and power. Both pyrolysis and heterogeneous gasification occur in commercial entrained-flow gasifiers at pressures from 4 to 65 atm with local gas temperatures as high as 2000 °C. Many gasification studies have been performed at moderate temperatures, heating rates, and pressures. In this work, both pyrolysis and char gasification experiments were performed on coal, petroleum coke, and biomass at conditions pertinent to commercial entrained-flow gasifiers. Rapid biomass pyrolysis experiments were performed at atmospheric pressure in an entrained-flow reactor for sawdust, switchgrass, corn stover, and straw mostly using a peak gas temperature of 1163 K at particle residence times ranging from 34 to 113 ms. Biomass pyrolysis was modeled using the Chemical Percolation Devolatilization model assuming that biomass pyrolysis occurs as a weighted average of its individual components (cellulose, hemicellulose, and lignin). Thermal cracking of biomass tar into light gas was included using a first-order model with kinetic parameters regressed in the current study. Char gasification rates were measured for biomass, petroleum coke, and coal in a pressurized entrained-flow reactor at high heating-rate conditions at total pressures between 10 and 15 atm. Peak centerline gas temperatures were between 1611 and 1879 K. The range of particle residence times used in the gasification experiments was 42 to 275 ms. The CO2 gasification rates of biomass and petroleum coke chars were measured at conditions where the reaction environment consisted of approximately 40 and 90 mol% CO2. Steam gasification rates of coal char were measured at conditions where the maximum H2O concentration was 8.6 mol%. Measured data was used to regress apparent kinetic parameters for a first-order model that describes char conversion. The measured char gasification rates were far from the film-diffusion limit, and are pertinent for pulverized particles where no internal particle temperature gradients are important. The modeling and measured data of char gasification rates in this research will aid in the design and efficient operation of commercial entrained-flow gasifiers, as well as provide validation for both existing and future models at a wide range of temperatures and pressures at high heating-rate conditions.

[pt] Procedimentos e processos são essenciais para garantir a qualidade de qualquer operação. Porém, o processo realizado na prática nem sempre está de acordo com o processo idealizado. Além disso, uma análise mais refinada de gargalos e inconsistências só é possível a partir do registro de eventos do processo (log). Mineração de processos (process mining) é uma área que reúne um conjunto de métodos para reconstruir, monitorar e aprimorar um processo a partir de seu registro de eventos. Mas, ao aplicar as soluções já existentes no log de uma unidade de coqueamento retardado, os resultados foram insatisfatórios. O núcleo do problema está na forma como o log está estruturado, carecendo de uma identificação de casos, essencial para a mineração do processo. Para contornar esse problema, aplicamos agrupamento hierárquico aglomerativo no log, separando as válvulas em grupos que exercem uma função na operação. Desenvolvemos uma ferramenta (PLANTSTATE) para avaliar a qualidade desses grupos no contexto da planta e ajustar conforme a necessidade do domínio. Identificando os momentos de ativação desses grupos no log chegamos a uma estrutura de sequência e paralelismo entre os grupos. Finalmente, propomos um modelo capaz de representar as relações entre os grupos, resultando em um processo que representa a operações em uma unidade de coqueamento retardado. / [en] Procedures and processes are essential to guarantee the quality of any operation. However, processes carried out in the real world are not always in accordance with the imagined process. Furthermore, a more refined analysis of obstacles and inconsistencies is only possible from the process events record (log). Process mining is an area that brings together a set of methods to rebuild, monitor and improve processes from their log. Nevertheless, when applying existing solutions to the log of a delayed coker unit, the results were unsatisfactory. The core of the problem is how the log is structured, lacking a case identification, essential for process mining. To deal with this issue, we apply agglomerative hierarchical clustering in the log, separating the valves into groups that perform a task in an operation. We developed a tool (PLANTSTATE) to assess the quality of these groups in the context of the plant and to adjust in accord to the needs of the domain. By identifying the moments of activation of these groups in the log we arrive at a structure of sequence and parallelism between the groups. Finally, we propose a model capable of representing the relationships between groups, resulting in a process that represents the operations in a delayed coker unit.