<p>There are many types of bioreactors used for producing bacteria populations in commercial, medical and research applications. </p><p>This report presents a systematic discussion of some of the most important models corresponding to the well known reproduction kinetics such as the Michaelis-Menten kinetics, competitive substrate inhibition and competitive product inhibition. We propose a modification of a known model, analyze it in the same manner as known models and discuss the most popular types of bioreactors and ways of controlling them. </p><p>This work summarises much of the known results and may serve as an aid in attempts to design new models.</p>

There are many types of bioreactors used for producing bacteria populations in commercial, medical and research applications. This report presents a systematic discussion of some of the most important models corresponding to the well known reproduction kinetics such as the Michaelis-Menten kinetics, competitive substrate inhibition and competitive product inhibition. We propose a modification of a known model, analyze it in the same manner as known models and discuss the most popular types of bioreactors and ways of controlling them. This work summarises much of the known results and may serve as an aid in attempts to design new models.

Two computer programs were developed and used to determine the optimum operating parameters of a fedbatch and a continuous two-stage process for fermentation of recombinant bacteria. The study was conducted in three phases: (a) developing two computer programs for simulation and optimization of the above processes, (b) conducting batch culture fermentations to verify the performance of the biokinetic model, and (c) conducting fedbatch and two-stage continuous fermentation experiments to closely examine the simulation and optimization results. The Miao and Kompala (1992) biokinetic model was used for simulation of the bacterial growth and cloned gene expression. The Pattern-Search method, developed by Hooke and Jeeves (1962), was incorporated in the programs to determine the optimum values of the parameters. Extensive studies of the optimization results showed 30-40% higher productivities for the two stage continuous process over the fedbatch process when using the same media in both processes. In addition, increasing the number of stages in the continuous two-stage process resulted in very limited improvement in the productivity of the process (10-12%). The information from the process optimization was then used to design batch, fedbatch nd two stage continuous experiments. Recombinant <i>E. coli </i>(strain BL21DE3) with an inducible gene (sensitive to IPTG, isopropyl-â-D-thiogalactopyranoside) was used throughout the experiments. The experimental results from the fedbatch and two stage continuous processes clearly showed good agreement with the simulation and optimization results $(\cong$15% deviation). The experiments also revealed that the maintenance of plasmid harboring cells over the long-term operation could be an important barrier in achieving the predicted high productivity in the two stage continuous process. Finally, in addition to computer programs for optimization of genetically modified microorganisms, a new computer program with a generic algorithm for optimization of multiple CFSTR fermentation with any kind of biokinetic model was developed. The program was used to optimize multiple CFSTRs with the cybernetic biokinetic model for the first time. Besides finding the optimum residence times for multiple CFSTRs operation, the effect of inaccuracies in different cybernetic model parameters on the overall productivity of the process was investigated. The simulation results illustrated that, a single CFSTR was more sensitive in its operation to inaccuracies in the biokinetic constants as compared to optimized CFSTRs in series (2-8 times more sensitive).

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Le micromélange, ou mélange à l'échelle moléculaire, a une influence déterminante sur la qualité des produits, la sélectivité, et le rendement de réactions d'importance industrielle comme les réactions de polymérisation. A l'heure actuelle, les systèmes chimiques existants sont bien adaptés à l'étude du micromélange de produits faiblement visqueux, mais il n'existe pas de méthode simple et opérationnelle pour les fluides plus visqueux. Inscrite dans le cadre du projet ANR PROCIP, l'étude a consisté à mettre en place une nouvelle méthode de quantification de l'efficacité du micromélange en milieu visqueux dans des réacteurs agités. La méthode utilisée s'inspire d'un système chimique basé sur deux réactions concurrentes, le système de réaction test iodure-iodate, dont la sélectivité d'un des produits est une mesure de l'efficacité du micromélange. L'approche propose un nouveau protocole basé sur le choix d'un tampon phosphate et l'utilisation de l'HydroxyEthylCellulose (HEC, 720 000 g/mol) comme agent viscosifiant inerte, qui possède un fort pouvoir viscosifiant permettant d'augmenter significativement la viscosité sans en ajouter plus de 1 % en masse dans le milieu. Des essais de caractérisation du micromélange en réacteur agité ont mis en évidence le ralentissement du micromélange au fur et à mesure que la viscosité augmente pour des pourcentages en HEC inférieurs à 0,5 %. Par contre, au-delà de 0,5 %, une « amélioration » du micromélange a été observée dans une large gamme de conditions expérimentales (différentes concentrations de réactifs, positions de l'injection, vitesses d'agitation et mobiles d'agitation). Plusieurs causes potentielles ont été formulées en vue d'expliquer ce phénomène et les cinétiques des réactions mises en jeu ont également été étudiées en présence de l'agent viscosifiant HEC et s'avèrent être inchangées. Enfin, une étude des interactions possibles entre les espèces iodées et l'HEC a été réalisée pour étudier l'existence d'une réaction parasite qui pourrait expliquer les résultats obtenus / Micromixing, or mixing at the molecular scale, has a decisive influence on product quality, selectivity and yield of industrially important reactions such as polymerization reactions. Currently, the existing chemical systems are well suited to the study of micromixing of low viscosity products, but no reliable characterization method exists for highly viscous media. As a part of the ANR project PROCIP, the study consisted in developing a new method to quantify the efficiency of micromixing in viscous media in stirred reactors. The method used is inspired by a chemical system based on two competitive reactions, the iodide-iodate test reaction system whose selectivity of a product is a measure of the micromixing efficiency. The approach proposes a new protocol based on a phosphate buffer and the use of HydroxyEthylCellulose (HEC, 720,000 g / mol) as an inert viscosifying agent, enabling to significantly increase the viscosity without adding more than 1 % by mass in the medium. Characterization of micromixing in a stirred reactor showed the slowing down of micromixing as viscosity increases for percentages of HEC below 0.5 %. By contrast, above 0.5 %, an "improvement" of micromixing has been observed in a wide range of experimental conditions (different concentrations of reactants, injection positions, stirring speeds and impellers). Several possible causes have been made to explain this phenomenon unexpected and the kinetics of the reactions involved were also studied in the presence of the viscosifying agent HEC and appeared to be unchanged. Finally, a study of possible interactions between iodine species and HEC was performed to study the existence of a secondary reaction which could explain the results

Les carburants synthétisés à partir de la biomasse représentent une alternative crédible aux carburants conventionnels. La biomasse lignocellulosique présente en effet une importante disponibilité et son traitement physico-chimique permet d’obtenir une grande variété de composés aux propriétés intéressantes. La structure de ces biocarburants fait cependant intervenir des fonctions oxygénées, qui rendent la compréhension des phénomènes d’oxydation complexes. Le projet 2G-CSAFE, dans lequel s’inscrit le travail présenté ici, a pour objectif d’explorer la cinétique d’oxydation de certains de ces carburants. Les fonctions chimiques étudiées lors de ce travail sont les fonctions cétone, éther et ester. La combinaison de deux de ces fonctions (comme dans le cas des lévulinates) est également étudiée. Après une étude bibliographique qui vise à identifier les informations apportées par les études passées sur les composés les plus simples de chaque famille (acétone, diméthyl-éther et formiate de méthyle), l’accent est mis sur les rares travaux disponibles liés à la butanone, la cyclopentanone, la cyclohexanone, le dibutyl-éther, le formiate de butyle et le lévulinate de méthyle. La cinétique d’oxydation de ces composés est ensuite étudiée par des approches numériques et expérimentales. Des calculs de chimie théorique sont menés dans un premier temps pour étudier l’impact des fonctions oxygénées sur la structure du carburant et pour obtenir les constantes de vitesse relatives aux principales réactions mises en jeu. Des expériences en réacteur auto-agité par jets gazeux sont ensuite réalisées sur une gamme de température pouvant aller de 450 à 1250 K, à des pressions de 1 ou 10 atm et pour des richesses allant de 0,5 à 2. Les données ainsi collectées sont enfin utilisées pour développer des mécanismes cinétiques. L’accord entre les simulations et les données expérimentales est globalement satisfaisant pour des composés aussi complexes et les résultats présentés ici pourront être source d’analogies pour la modélisation d’autres carburants oxygénés. / Fuels produced from biomass are an interesting alternative to conventional fuels. Lignocellulosic biomass is indeed highly available and a wide variety of compounds can be obtained through its physico-chemical conversion. However, the structure of the fuels obtained from such processes involves oxygenated groups that make complicated the understanding of the oxidation chemistry. The work presented here is part of the 2G-CSAFE project, which aims at exploring the oxidation kinetics of these fuels. Chemical functions studied in this work include ketones, ethers and esters. The combination of two functions (as for levulinates) is also investigated. After a literature review aiming at collecting the information reported on the simplest compound of each group (acetone, dimethylether and methylformate), available studies on butanone, cyclopentanone, cyclohexanone, dibutyl-ether, butyl-formate and methyl levulinate are considered. The oxidation of these compounds is thereafter studied by numerical and experimental approaches. Ab initio calculations are performed to study the impact of the oxygenated groups on the structure and to derive rate constants for the major chemical pathways. Experiments are then carried out in a jet-stirred reactor for temperatures ranging from 450 to 1250 K, pressures of 1 or 10 atm and equivalence ratios from 0.5 to 2. The data obtained through these two approaches are finally used to develop and validate kinetic mechanisms. The overall agreement between experiments and simulations is satisfactory and results presented here can be used as a source of analogy for the future modeling of other similar oxygenated fuels.

Un grand nombre d’industries (chimiques, pharmaceutiques et agroalimentaires) utilisent, produisent ou transforment des fluides complexes. Ce sont des fluides à viscosité élevée, souvent de comportement non-Newtonien. Leur préparation nécessite souvent une étape de chauffe suivie d’une étape de refroidissement. La chauffe est indispensable afin de faciliter la fabrication (réaction chimique et/ou transformation physico-chimique). Le refroidissement, ou encore l’étape de finition, consiste à amener les fluides jusqu’à une température proche de la température ambiante pour aborder l'étape de conditionnement. Le refroidissement est le plus souvent réalisé « in situ » dans la même cuve agitée, équipée d’une double enveloppe (utilisée pour la fabrication), mais des technologies en continu peuvent également être envisagées. Ces travaux de thèse portent sur la mise en place d’une méthodologie de pilotage de la vitesse d’agitation lors du refroidissement de fluides complexes dans des cuves agitées, ainsi que sur la comparaison des performances de la cuve agitée avec celles du mélangeur statique. Deux fluides de travail sont testés : Newtonien et viscoplastique, en régime d’écoulement laminaire et transitoire. Nous déterminons les limites de l’influence de l’agitation sur le transfert thermique, la durée de l’opération et la quantité d’énergie consommée. En premier lieu, le refroidissement est étudié à l’échelle laboratoire (réacteur de 0,6L). Il a été constaté que le changement de la vitesse d’agitation au cours du refroidissement affecte le profil de température. Cela a un impact avantageux sur le coût énergétique et/ ou la durée de refroidissement. Les tendances observées à l’échelle laboratoire sont transposées et validées à l’échelle pilote (réacteur de 60L). Puis deux types de mélangeurs statiques sont étudiés comme technologie en continu. Nous établissons des modèles de perte de charge que nous utilisons dans la détermination de l’énergie dépensée pour le refroidissement. Ensuite nous réalisons une comparaison de leurs performances en fonction des facteurs d’efficacité de transfert thermique et de consommation énergétique. Enfin, une brève analyse comparée est exposée, présentant les divers critères de choix entre la cuve agitée et la technologie en continu. / Highly viscous Newtonian and non-Newtonian fluids are frequently encountered in the process industries (like pharmaceutical, food and cosmetics). The preparing of such products involves heating and cooling steps. The heating stage is essential in order to facilitate the production (chemical reaction and/or physico-chemical transformation). The cooling step, named also final stage, leads the fluids to ambient temperature and prepares them for the conditioning. The cooling is mostly realized "in situ" in the same double jacketed stirred vessel, (used for the manufacturing), but continuous technologies may also be employed. This study aims to investigate the cooling of highly viscous fluids, and intends to define the best conditions for controlling the impeller speed (constant or variable) in a stirred vessel, as well as to compare the performances of the stirred vessel with those of the static mixer. Two fluids are tested: a Newtonian and a Non-Newtonian yield-stress fluid, in laminar and transitional conditions. The limits of the influence of the impeller speed on the heat transfer, the duration and the energy consumption are determined. In a first approach, the cooling is studied at small scale (0,6L vessel). The variation of the impeller speed during the cooling, affects the profile of temperature. This type of procedure has an advantageous impact on the energy cost and / or the duration of the cooling. The observed tendencies at a small scale are transposed and validated at a pilot scale (60L vessel). Two types of static mixers are studied as continuous technology. Models of pressure drop are established, which are used further in the determination of the energy consumption for the cooling. The performances of these two static mixers are compared, according to the factors of heat transfer efficiency and energy consumption. Finally, a brief comparative analysis is exposed, presenting diverse criteria of choice between the stirred tank and the continuous technology.

Les énergies fossiles sont largement utilisées depuis les années 1900 pour satisfaire l’augmentation mondiale de la demande d’énergie. Cependant, la combustion est un procédé qui libère des polluants comme le CO2 et les NOx. Un des principaux challenges du 21ème siècle est de réduire ces émissions et les constructeurs automobiles sont impliqués dans cette course. Pour augmenter le rendement des moteurs à pistons, des solutions techniques, tels que le "downsizing", sont développées. Cette technique consiste à réduire la cylindrée des moteurs tout en maintenant leurs performances grâce à un turbocompresseur qui permet d’augmenter la masse enfermée dans la chambre de combustion. Malheureusement, l’augmentation de la pression dans les cylindres induite par le turbocompresseur est à l’origine de combustions anormales : des variations cycles à cycles importantes apparaissent, les gaz frais peuvent s’auto-allumer (allumage avant le claquage de la bougie) entrainant des phénomènes de cliquetis ou de rumble. La Simulation aux Grandes Echelles (SGE) a déjà prouvé qu’elle était un outil fiable pour prédire ces combustions anormales. Cependant ces calculs reposent sur des modèles pour prédire la propagation de la flamme dans la chambre de combustion. Ces modèles sont généralement issus de corrélations réalisées dans des cas où la turbulence est supposée homogène et isotrope. Définir théoriquement ou numériquement une telle turbulence est relativement simple mais expérimentalement la tâche est plus délicate. Cette thèse s’intéresse à un dispositif classiquement utilisé: une enceinte fermée dans laquelle la turbulence est générée par des ventilateurs. L’objectif de ce travail est donc double: 1. caractériser la turbulence générée dans ce type d’enceinte pour vérifier si elle est homogène et isotrope. 2. caractériser finement la combustion, laminaire et turbulente, afin d’enrichir les connaissances dans ce domaine et ainsi améliorer les modèles utilisés. Une première étude sur la propagation des flammes laminaires a été menée. Elle présente les effets de l’étirement et du confinement sur la vitesse de flamme laminaire. La principale difficulté pour la simulation de l’enceinte complète consiste à trouver une méthode numérique permettant de reproduire précisément l’écoulement généré par un ventilateur mais aussi d’en gérer plusieurs simultanément. Deux méthodes ont alors été testées. Premièrement, une méthode type Frontières Immergées a été implémentée dans le code de calcul AVBP. Malgré les bons résultats obtenus sur des cas tests simples, cette méthode ne s’est pas montrée adaptée pour reproduire précisément l’écoulement généré par un seul ventilateur. Une autre approche, provenant du monde du calcul des turbomachines, et basée sur le couplage de codes (appelée MISCOG), a quant à elle démontré ses capacités à le faire et est donc utilisée pour calculer l’écoulement généré par les six ventilateurs à l’intérieur de l’enceinte. L’écoulement non réactif est d’abord analysé: les résultats montrent qu’il existe une zone d’environ 6 cm de diamètre au centre de l’enceinte dans laquelle la vitesse moyenne de l’écoulement est proche de zéro et dans laquelle la turbulence est quasiment homogène et isotrope. Enfin, le pré-mélange de gaz frais est allumé en déposant un noyau de gaz chauds au centre de l’enceinte et la phase de propagation turbulente est analysée. En particulier, il est montré que la température des gaz brulés déposés au moment de l’allumage est un paramètre critique. / Fossil energy is widely used since the 1900s to satisfy the global increasing energy demand. However, combustion is a process releasing pollutants such as CO2 and NOx. One of the major challenges of the 21th century is to reduce these emissions and car manufacturers are involved in this race. To increase fuel efficiency of piston engines, some technical solutions are developed such as ‘downsizing’. It consists in reducing the engine size while maintaining its performances using a turbocharger to increase the trapped mass in the combustion chamber. Unfortunately, downsizing can lead to abnormal combustions: intense cycle to cycle variations can appear, the fresh mixture can auto-ignite (ignition before spark-plug ignition) leading to knock or rumble. Large Eddy Simulation has proven to be a reliable tool to predict these abnormal combustions in real engines. However, such computations are performed using models to predict the flame propagation in the combustion chamber. Theses models are generally based on correlations derived in cases where turbulence is assumed to be homogeneous and isotropic. Defining theoretically or numerically such a turbulence is a simple task but experimentally it is more challenging. This thesis focuses on a apparatus used in most experimental systems: fans stirred vessel. The objective of this work is twofold: 1. characterize the turbulence generated inside the vessel to check wether it is homogeneous and isotropic or not, 2. finely characterize laminar and turbulent combustion in this setup in order to increase the knowledge in this field, and thereby improve models used. First, a laminar flame propagation study has been conducted to address both confinement and curvature effects on the laminar flame speed in a spherical configuration. The main difficulty to perform the simulation of the whole configuration consists in finding a numerical method able to compute accurately the flow generated by one fan and able to handle six fans simultaneously too. Two numerical methodologies have been tested. First an Immersed Boundaries method was implemented. Despite good results obtained on academic test cases, this method was shown to be unadapted to compute accurately the flow generated by one fan. On the other hand, a numerical approach, coming from turbomachinery calculations and based on code coupling (called MISCOG), demonstrates its ability to do it and it is used to compute the flow generated by the six fans inside the closed vessel. Non-reacting flow is first analyzed and reveals a zone at the vessel center of around 6 cm of diameter where mean velocity is near zero and turbulence is almost homogeneous and isotropic. After that, the premixed fresh mixture is ignited depositing a hot gases kernel at the vessel center and the turbulent propagation phase is analyzed. In particular, it is shown that the amount of energy deposited at ignition is a critical parameter.

Orientador: Jose Roberto Nunhez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-10T17:37:46Z (GMT). No. of bitstreams: 1 Spogis_Nicolas_M.pdf: 4452795 bytes, checksum: 7a20afda92e9e3627bb4f46cbb630b88 (MD5) Previous issue date: 2002 / Resumo: Tanques de mistura são muito usados na indústria química, petroquímica, farmacêutica e alimentícia, onde a eficiência das operações de mistura freqüentemente tem um grande impacto no custo de produção e na qualidade do produto. O objetivo deste trabalho é determinar curvas para Número de Potência versus Número de Reynolds, para os impelidores mais comumente utilizados na indústria química, através da fluidodinâmica computacional. Os principais fluxos gerados pelos impelidores estudados serão determinados tanto para escoamentos laminares quanto turbulentos, calculando-se o bombeamento gerado e os padrões de circulação gerados no tanque. Através dos resultados numéricos gerados pelo modelo proposto, serão determinadas correlações empíricas para as curvas para Número de Potência versus Número de Reynolds, a fim de gerar uma ferramenta útil e prática para utilização em projetos de sistemas de agitação e ¿scale-up¿. O presente trabalho tem como objetivo mostrar que um projeto adequado de um sistema de mistura pode minimizar os gastos energéticos do equipamento e seu tempo de processamento, além de melhorar a uniformidade do processo, impedindo, ou minimizando, a formação de zonas mortas. A fluidodinâmica computacional mostrou que tem um grande potencial para melhorar sistemas de agitação, permitindo aos engenheiros simular o desempenho de sistemas alternativos, tentando emparelhar parâmetros de operação, projeto mecânico e manipulação das propriedades fluidas ou, então, otimizar sistemas reacionais já implantados na indústria / Abstract: Stirred vessels are widely used in chemical, petrochemical, pharmaceutical and food industries, where the mixing efficiency of the mixture frequently has a great impact in the product production cost and quality. The objective of this work is to build curves of Power Number versus Reynolds Number, for the most commonly used impellers in the chemical industry, through the use of CFD -computational fluid dynamics. The main flow generated by the studied impellers, the pumping number and the flow patterns in the tank will be determined. Through the numeric results generated by the proposed model, it is determined empiric correlations for Power Number versus Reynolds Number curve, in order to generate a useful and practical tool to be used in the design and scale-up of agitation systems. The present work aims to show that an optimized project of a mixture system can minimize the equipment power consumption and its processing time, improving uniformity for the whole process, minimizing the formation of dead zones. The computational fluid dynamics has proved to have a great potential to improve agitation systems, allowing the engineers to simulate alternative systems, trying to match operation parameters, equipment design and the fluids properties and also optimizing reactors that already implanted in the industry / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Submitted by Neusa Fagundes (neusa.fagundes@unioeste.br) on 2017-09-05T19:08:26Z No. of bitstreams: 1 Thiago_Edwiges2017.pdf: 2041114 bytes, checksum: f435c702dd49431aa0534c4ce49e2533 (MD5) / Made available in DSpace on 2017-09-05T19:08:26Z (GMT). No. of bitstreams: 1 Thiago_Edwiges2017.pdf: 2041114 bytes, checksum: f435c702dd49431aa0534c4ce49e2533 (MD5) Previous issue date: 2017-08-18 / The economical development and urbanization process have contributed to the increase in solid waste generation and problems related to final disposal. Thus, the National Solid Waste Policy reinforces treatment in order to improve efficiency in the management of solid waste as one of its priorities and stimulates to recover and use energy. Anaerobic digestion has been suggested as a promising approach to the treatment of organic fraction of solid waste, mainly because it represents an opportunity to reduce environmental pollution and minimizes impacts concerning the energy crisis. So, this trial aimed at evaluating FVW biogas potential, collected in a wholesale market (Unit from Foz do Iguaçu/PR) through batch and semicontinuous tests. Fruits and vegetables trading from that unit generates approximately 70,500 t year-1, with 2,800 kg d-1 solid waste, composed of almost 85% organic matter. The influence of chemical composition of twelve FVW different samples with different compositions on biochemical methane potential (BMP) was analyzed. The BMP ranged from 288 LN CH4 kg VS-1 to 516 LN CH4 kg VS-1, with significant statistical differences among means. This was explained by in the waste chemical composition over time. BMP variation was most strongly correlated for lipid content and high calorific values (HCV). Linear regression analyses were carried out to develop statistical models to predict as fast as possible methane potential of this kind of waste. The models were analyzed according to chemical compounds and HCV based on simple and multiple regression. The model with the best statistical metrics included lipid, protein, cellulose, lignin, and HCV, with a 92.5% R² and lignin content negatively correlated to BMP. Since HCV and lipids were strongly correlated, and because HCV can be determined more rapidly than chemical composition, HCV may be useful for predicting BMP. In addition to batch tests, the performance of anaerobic digestion was also investigated in a semicontinuous mode using a FVW mixture as a single substrate. The performance of a continuous stirred tank reactor (CSTR) was monitored along with the gradual increase of organic loading rates (OLR) from 0.5 gVS L–1 d–1 to 5.0gVSL–1d–1. BMP of FVW used as a feedstock to CSTR was 370 LN CH4 kg VS-1 with 81% biodegradability. During the whole trial pH was stable and there was an adequate level of buffering capacity in the system. Volumetric biogas production (LN biogas L–1 d–1) increased linearly (R² = 94.4%) according to OLR increase. On the other hand, the specific methane production (LN CH4 kg VS-1) has registered the best performance at an OLR of 3.0 g VS L–1 d–1 and 30 days of hydraulic retention time, with 285 LN CH4 kg VS-1 added, reaching 74% of BMP measured by batch tests. A clear accumulation of volatile fatty acids (VFA) was monitored with a decreased specific methane yield was detected with an OLR above 3.0 g VS L–1 d–1. / O crescimento econômico e o processo de urbanização vêm contribuindo para o aumento da geração de resíduos sólidos e problemas relacionados à disposição final. A Política Nacional de Resíduos Sólidos reforça o tratamento com o intuito de melhorar a eficiência quanto ao gerenciamento dos resíduos sólidos no país, como uma de suas prioridades e enfatiza o incentivo à recuperação e ao aproveitamento energético. A biodigestão anaeróbia tem sido apontada como uma abordagem promissora ao tratamento da fração orgânica dos resíduos sólidos, sobretudo por representar oportunidade de reduzir a poluição ambiental e minimizar os impactos da crise energética. Assim, o objetivo deste trabalho foi avaliar o potencial de produção de biogás de resíduos de frutas e hortaliças (RFH) coletados na Central de Abastecimento (CEASA – Unidade de Foz do Iguaçu/PR) a partir de testes em batelada e em regime semicontínuo. A comercialização de frutas e hortaliças da unidade é de aproximadamente 70.500 t ano-1, com geração de resíduos sólidos de 2.800 kg d-1, compostos por aproximadamente 85% de matéria orgânica. A influência da composição química de doze amostras de RFH com diferentes composições sobre o potencial bioquímico de metano (PBM) foi analisada. O PBM dos resíduos variou entre 288 LN CH4 kg SV-1 e 516 LN CH4 kg SV-1, com diferenças estatísticas significativas entre as médias, o que pôde ser explicado pela variação na composição química dos resíduos ao longo do tempo. A variação do PBM foi mais fortemente correlacionada à variação do teor de lipídeos e do poder calorífico superior (PCS). Foram realizadas análises de regressão linear visando desenvolver modelos estatísticos para estimar, de forma mais rápida, o potencial metanogênico deste tipo de resíduo. Os modelos foram analisados considerando os componentes químicos e o PCS a partir de regressão linear simples e múltipla. O modelo com as melhores métricas estatísticas foi obtido considerando lipídio, proteína, celulose, lignina e PCS, com R² de 92,5% e com teor de lignina negativamente correlacionado ao PBM. Como o PCS e os lipídeos apresentaram forte correlação, e como o PCS pode ser determinado, em geral, de forma mais rápida que a composição química, o PCS pode ser considerado um parâmetro útil para a estimava do PBM. Além dos testes em batelada, investigou-se também o desempenho da biodigestão anaeróbia em regime semicontínuo utilizando-se uma mistura de RFH como único substrato. O desempenho de reator de mistura completa (do inglês CSTR) foi monitorado juntamente com o aumento gradativo da carga orgânica volumétrica (COV) de 0,5 g SV L-1 d-1 até 5,0g SV L-1 d-1. O PBM dos RFH utilizado para alimentar o reator foi 370 LN CH4 kg SV-1 com biodegradabilidade de 81%. Durante todo o ensaio o pH se manteve estável e o sistema apresentou boa capacidade tampão. A produção volumétrica de biogás (LN biogás L-1 d-1) aumentou de forma linear (R² = 94,4%) de acordo com aumento da COV. Já a produção específica de metano (LN CH4 kg SV-1) indicou o melhor desempenho com COV de 3,0 g SV L-1 d-1 e 30 dias de tempo de retenção hidráulica, com 285 LN CH4 kg SV-1 adicionados, e atingiu 74% de PBM, medido a partir dos testes em batelada. Observou-se um acúmulo evidente de ácidos graxos voláteis (AGV), com consequente redução da produção de metano a partir da COV acima de 3,0 g SV L-1 d-1.