A sacarose é uma matéria-prima em franca expansão de produção no Brasil, seu maior produtor e exportador. Essa molécula pode ser convertida, através de um processo multienzimático, em produtos de maior valor agregado: frutose e ácido glicônico, os quais são importados pelo país, e amplamente utilizados em indústrias químicas, de produção de fármacos e setores alimentícios. Neste estudo, avaliou-se a hidrólise da sacarose pela invertase assim como a conversão da glicose em ácido glicônico, pela ação da glicose oxidase, ambas em processo descontínuo-alimentado. A solução de substrato (64g/L-sacarose; 32g/L-glicose) foi adicionada segundo as seguintes leis: constante, linear crescente, linear decrescente, exponencial crescente e exponencial decrescente. No caso da glicose, foi necessária a utilização de enzima auxiliar, a catalase, para degradar a água oxigenada formada durante a conversão da glicose. Mediante os resultados dos testes com os dois substratos, realizou-se teste de conversão direta da sacarose em frutose e ácido glicônico, utilizando-se invertase, glicose oxidase e catalase em regime descontínuo-alimentado, com alimentação linear decrescente (melhor resultado para ambos os substratos). No procedimento contínuo, alvo principal do trabalho, utilizou-se reator com membrana, da marca MILLIPORE ®, integrando em uma única etapa a conversão catalítica, a separação/concentração do produto e a recuperação do biocatalisador. A temperatura foi controlada por circulação de água, tendo acoplado uma bomba peristáltica (para controlar a vazão de alimentação do substrato) e um sistema de pressurização. O reator operou com membrana de ultrafiltração (corte molecular = 100 kDa) e foi mantido sob agitação constante. Os parâmetros de partida foram, a princípio, fixados de acordo com os valores otimizados no reator descontínuo-alimentado com o emprego simultâneo das enzimas. / Sucrose is a commodity largely produced in Brazil and one of the most used and commercialized product in food industry. It can be converted through a multienzyme process in fructose and gluconic acid, which have commercial values higher than sucrose. Both products are imported by Brazil, being largely employed in the chemical, food and pharmaceutical industry. This work dealt with the hydrolysis of sucrose by invertase into fructose and glucose, and the oxidation of glucose to gluconic acid by glucose oxidase and catalase. Catalase was added in order to decompose the hydrogen peroxide an inhibitor of glucose oxidase formed as by-product of the oxidation. Two processes were employed. Fed-batch in which the hydrolysis and oxidation reactions were carried out separately by adding invertase followed by glucose oxidase and catalase was conducted by adding the solution of substrate according to a constant, increasing linear, decreasing linear, increasing exponential or decreasing exponential mode. The best fed-batch performance was attained through the decreasing linear addition of sucrose (64g/L) and glucose (32g/L). Setting this kind of addition and using all enzymes simultaneously, the direct conversion of sucrose to fructose and gluconic acid occurred at a yield of 72%. The continuous process was carried out in a cell-type membrane reactor (membrane cut off = 100 kDa), in which the sucrose conversion was made by using all enzymes simultaneously, leading to a final yield of about 76%

Membrane-based separation processes have been used extensively for drinking water purification, wastewater treatment, and numerous other applications. Reactive membranes synthesized through functionalization of the membrane pores offer enhanced reactivity due to increased surface area at the polymer-solution interface and low diffusion limitations. Oxidative techniques utilizing free radicals have proven effective for both the destruction of toxic organics and non-environmental applications. Most previous work focuses on reactions in the homogeneous phase; however, the immobilization of reactants in membrane pores offers several advantages. The use of polyanions immobilized in a membrane or chelates in solution prevents ferric hydroxide precipitation at near-neutral pH, a common limitation of iron(Fe(II/III))-catalyzed hydrogen peroxide (H2O2) decomposition. The objectives of this research are to develop a membrane-based platform for the generation of free radicals, degrade toxic organic compounds using this and similar solution-based reactions, degrade toxic organic compounds in droplet form, quantify hydroxyl radical production in these reactions, and develop kinetic models for both processes. In this study, a functionalized membrane containing poly(acrylic acid) (PAA) was used to immobilize iron ions and conduct free radical reactions by permeating H2O2 through the membrane. The membrane’s responsive behavior to pH and divalent cations was investigated and modeled. The conversion of Fe(II) to Fe(III) in the membrane and its effect on the decomposition of hydrogen peroxide were monitored and used to develop kinetic models for predicting H2O2 decomposition in these systems. The rate of hydroxyl radical production, and hence contaminant degradation can be varied by changing the residence time, H2O2 concentration, and/or iron loading. Using these membrane-immobilized systems, successful removal of toxic organic compounds, such as pentachlorophenol (PCP), from water was demonstrated. Another toxic organic compound of interest for water treatment applications is trichloroethylene (TCE). Due to its limited solubility in water, a majority of the TCE is often present in the form of droplets. In this study, effective TCE droplet degradation using chelate-modified, iron-catalyzed free radical reactions at near-neutral pH was demonstrated. In order to predict the degradation of aqueous and non-aqueous phase TCE for these reactions, a mathematical model was constructed through the use of droplet mass transfer correlations and free radical reaction kinetics.

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Orientador: Teresa Massako Kakuta Ravagnani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-08T19:44:43Z (GMT). No. of bitstreams: 1 Araujo_PauloJardelPereira_M.pdf: 1672087 bytes, checksum: 39df6a7017efe009f53dbd9aecb301b1 (MD5) Previous issue date: 2007 / Resumo: Estireno é um importante monômero na fabricação de termoplásticos e borrachas sintéticas. Grande parte de sua produção é baseada na desidrogenação catalítica do etilbenzeno. O aumento da produtividade do estireno pode ser alcançado utilizando-se membranas permseletivas para remoção do hidrogênio, suprimindo as reações reversíveis e secundárias. Este trabalho apresenta a simulação do processo de desidrogenação em um reator tubular de leito fixo catalítico envolto em membrana composta permseletiva. A modelagem matemática desenvolvida considera os diferentes mecanismos de transporte de massa que prevalecem nas várias camadas da membrana e no leito fixo catalítico. A remoção do Hidrogênio do leito catalítico foi realizada estabelecendo-se um gradiente de potencial químico de hidrogênio através da membrana. Duas formas de remoção de hidrogênio foram estudadas: pela aplicação de uma diferença de pressão através da membrana e pelo arraste com gás inerte. Um programa computacional foi implementado para descrever os perfis de temperatura, pressão e concentração ao longo de todo o reator, bem como a conversão do etilbenzeno, seletividade e produtividade de estireno. Comparando os resultados obtidos no leito fixo convencional operando na condição industrial padrão com os obtidos na aplicação de diferença de pressão através da membrana, observou-se um acréscimo na conversão de etilbenzeno de 19,89 % na mesma seletividade do estireno, representando um aumento de 19,12 % na produtividade de estireno. Este mesmo aumento foi também alcançado com o uso de gás de arraste inerte. Por este motivo, este procedimento é a opção mais recomendada, por agregar custo menor ao processo. Através da simulação do sistema em diferentes condições do processo e configurações do reator e da membrana, obteve-se um acréscimo de 40,98 % na produtividade de estireno comparada a do processo com leito fixo convencional / Abstract: Styrene is an important monomer in the manufacture of thermoplastic and synthetic rubbers. Most of the production is based on the catalytic dehydrogenation of ethylbenzene. The increase of the styrene productivity can be reached using permselectives membranes for hydrogen removal, suppressing the reversible and secondary reactions. This work presents the simulation of dehydrogenation process in tubular fixed bed reactor wrapped with permselective composite membrane. The mathematical modeling was developed considering the different mechanisms of mass transport that prevail in several membrane layers and in catalytic fixed bed. The removal of the permeated hydrogen was carried out establishing a gradient of chemical hydrogen potential through the membrane. Two forms of hydrogen removal were studied: the application of transmembrane pressure drop and the employment of inert sweep gas. A computational program was implemented to describe the profiles of temperature, pressure and concentration throughout all reactor, as . well as the ethylbenzene conversion, styrene selectivity and productivity. Comparing the simulation results obtained for conventional fixed bed reactor carried on standard industrial operation condition with application transmembrane pressure drop form, it shows an increase of 19.89 % in ethylbenzene conversion in the same styrene selectivity for, meaning an increase of 19.12% in styrene productivity. The same addition was obtained when the inert sweep gas was employed. Therefore, this last proceeding has been recommended as the better option, due to its lower operation cost. Through the system simulation at various operation conditions, using different reactor and membrane configurations, an increase of 40.98 % in the styrene productivity was reached comparing to conventional fixed bed process / Mestrado / Sistemas de Processos Quimicos e Informatica / Mestre em Engenharia Química

Ce travail a pour objectif la conception et l'étude d'un réacteur enzymatique à membrane (REM) en vue de la dégradation de composés phénoliques. Pour cela, des membranes actives ont été préparées par greffage covalent de la laccase de Trametesversicolor à la surface d'une membrane céramique Après avoir mis en évidence les potentialités du réacteur vis-à-vis de la dégradation du 2,6-diméthoxyphénol (DMP) choisi comme substrat modèle, l'impact de paramètres opératoires (débit d'alimentation, concentration en substrats) sur les performances du REM a été étudié. Pour résoudre des problèmes d'instabilité, différentes étapes du protocole de fabrication des membranes actives ont été revues. Puis les paramètres opératoires (pH et température) ont été étudiés afin d'optimiser les conditions de mise en œuvre du REM. Il a été établi que les performances épuratoires étaient maximales à pH acide (pH 4) mais restaient stables sur une large plage de températures (15 à 40°C). Enfin la dernière partie de la thèse a été consacrée à l'étude du colmatage et à la recherche de différentes stratégies visant à limiter l'impact de ce dernier sur les performances et la stabilité du REM. / This work was devoted to the design and the study of an enzymatic membrane reactor (EMR) for the degradation of phenolic compounds. For this, active membranes were synthesized by covalent grafting of laccase from Trametes versicolor on the surface of a porous ceramic membrane.The 2,6-dimethoxyphenol (DMP) was chosen as model substrate and the effect of operating parameters (feed flow rate, substrate concentration) on the performance of the EMR have been studied.Different stages of the active membrane preparation process were reviewed in order to improve the system stability. Moreover operating parameters (pH and temperature) were studied in order to optimize the performance of the EMR. It was shown that the depletion efficiency was maximal at relatively low pH (pH 4) but remained stable over a wide temperature range (15 to 40 ° C).Finally the last part of the work was devoted to the developmentof different strategies to limit the impact of fouling on the performance and stability of the EMR.

[ES] En la presente tesis se han desarrollados estudios sobre reactores de membrana de alta temperatura. Entre estos se puede diferenciar entre un trabajo experimental y un trabajo de simulación. En el bloque experimental se han desarrollado electrodos basados en cobre para reactores de membrana electroquímicos tubulares de alta temperatura basados en electrolitos protónicos. Para depositar estos electrodos sobre los tubos se han desarrollado diferentes técnicas. Se ha optimizado el método dip-coating para depositar un cermet basado en cobre utilizando la misma cerámica que el electrolito de los soportes tubulares. Las condiciones con las que se llevó a cabo el proceso de dip-coating provocan disminuciones de varios ordenes de magnitud en la resistencia de polarización del electrodo final. Se trata de un método que es muy sensible a posibles defectos en electrolito, como pequeñas grietas o poros, ya que el cobre del electrodo depositado se introduce por estos defectos reaccionando con el níquel del electrodo interno. Asimismo, se ha empleado el método de sputtering para depositar cobre metálico sobre soportes tubulares electroquímicos. Aumentar la temperatura de deposición genera mejores fijaciones electrodo-electrolito. Las celdas con el cobre depositado a alta temperatura mostraron resistencias de polarización inferiores a 0.1 ¿·cm^2. En el bloque de simulaciones mediante métodos de elementos finitos se han desarrollado diferentes modelos para la caracterización de los fenómenos que tienen lugar en reactores de membrana de alta temperatura. Se ha estudiado: (i) la permeación de oxígeno a través de una membrana de conducción iónica-electrónica mixta; (ii) la electrólisis del agua utilizando celdas basadas en conductores protónicos de alta temperatura; (iii) la integración de una celda protónica para la extracción de hidrógeno en un reformador de metano; (iv) la integración de una celda de conductividad co-iónica en la deshidroaromatización de metano en un reactor de lecho catalítico. El modelo de permeación de oxígeno a través de una membrana de conductividad mixta se ajustó a datos experimentales. El modelo ajustado ha permitido caracterizar la importancia del efecto dilutivo y de arrastre sobre el transporte de oxígeno a través de la membrana. Se ha observado que, aunque el efecto de arrastre tenga menor importancia que el dilutivo, su efecto es importante ya que previene la formación de concentraciones de polarización. El estudio de electrolizadores que utilizan conductores protónicos sólidos de alta temperatura ha permitido estudiar el efecto del escalado en este proceso y evaluar la eficiencia en el almacenamiento de energía. El modelo de un reactor de membrana electroquímico basado en conductores protónicos integrado en un reformador de metano ha permitido comprobar que la demanda térmica del proceso se cubre por el efecto Joule y la electrocompresión del hidrógeno. Se ha comprobado como el coarsening observado en las partículas de níquel no limita la extracción de hidrógeno para la celda estudiada. Un último modelo fue construido para estudiar un reactor de membrana para el proceso de deshidrogenación de metano utilizando una celda co-iónica. El modelo fue validado utilizando datos experimentales. Se utilizó el modelo validado para realizar estudios para analizar posibles limitaciones del proceso. Finalmente, se ha comprobado que el desplazamiento del equilibrio de reacción mediante la extracción de hidrógeno se frena debido a limitaciones cinéticas. / [CAT] Esta tesi presenta resultats sobre reactors de membrana a alta temperatura. Dos blocs diferenciades poden ser identificats: (i) treball experimental; (ii) treball de modelat. En el bloc experimental, elèctrodes basats en coure han siguts optimitzats per a tubular cells de conductor protòniques. La deposició de la capa basada en coure es va fer amb diferents tècniques. La tècnica de dip-coating ha sigut usada per a depositar una capa de cermet basada en coure. Aquesta tècnica es molt sensible a les condicions amb les que es desenvolupa la deposició perquè causa canvis de varis ordres de magnitud en la resistència de polarització del elèctrode. A més, la tècnica de sputtering ha sigut triada per a depositar coure. Per a depositar correctament la capa de coure, altes temperatures durant la deposició foren requerides. El elèctrode optimitzat presenta resistències de polarització inferiors a 0.1 ¿·cm2. En el treball de modelat, la metodologia de elements finits va ser utilitzada per a modelar diferents fenòmens concernits a reactors de membrana de elevada temperatura. La permeació de oxigen per membranes de conducció mixta ha sigut modelada per a avaluar la importància de la dilució i del arrossegament. Els resultats mostren que, encara que el efecte dilutiu es predominant, el efecte del arrossegament no pot ser depreciat. Un adequat arrossegament del oxigen permeat es necessari per evitar polaritzacions en la concentració del oxigen els quals limitarien la permeació. El efecte del arrossegament es major quan el gas portador es mes pesat. El model per estudiar un procés de electròlisis basat en conductors protòniques a elevada temperatura ha permès estudiar l'efecte de l'escalat de aquest procés i avaluar l'eficiència en l'emmagatzemament d'energia. Modelant un reformador de membrana protònica ha permès comprovar la microintegració tèrmica de tots el fenòmens que tenen lloc en aquest procés. Aquest procés compren les reaccions de reformat, extracció electroquímica de hidrogen i electrocompressió del hidrogen generat. La electrocompressió del hidrogen és un procés isoterma que allibera la energia demanda en forma de calor. El model ha permès comprovar que l'engrossiment de les partícules de níquel no limita l'extracció de hidrogen. Un últim model va ser construït per estudiar l'extracció de hidrogen en un reactor de membrana per al procés de dehidroaromatizatió de metà. El reactor de membrana utilitza materials co-iòniques per l'extracció de hidrogen de la càmera de reacció. Aquest model va ser validat amb resultats experimentals. El model va mostrar que no hi ha limitacions amb la difusió del hidrogen. A més, el desplaçament del equilibri mediant l'extracció de hidrogen està limitat per la baixa activitat cinètica del procés. / [EN] In this thesis several studies were developed about membranes reactor at high temperature. Two differentiated blocks could be identified: (i) experimental works; (ii) modelling works. In the experimental block, electrodes based on copper was developed for tubular protonic based cells. The deposition of the copper layer on the tubes was developed by different techniques. Dip-coating method was optimized to a copper-based cermet on the tube. Conditions of the dip-coating procedure has a critical impact in the final performance of the electrochemical cell whose supposes several orders of magnitude in the polarization resistance. It is a sensitive process with the defect of the tube as shows the copper spread over these defects. Additionally, sputtering technique was used to deposit copper layer on the tube. High temperature is required to achieve suitable attachments copper-tube. This high temperature deposited layer present polarization resistances lower than 0.1 ¿·cm2. In the modelling block, finite element methodology was used to build different models to study different phenomena concerning membrane reactors at high temperature. It was studied: (i) the oxygen permeation across a mixed ionic and electronic conducting membrane; (ii) water electrolysis based on high temperature protonic cells; (iii) hydrogen extraction from a steam methane reforming using a protonic cell; (iv) the intensification of the methane dehydromatization reactor using co-ionic membrane. Oxygen permeation model was built to evaluate the effect of the dilutive and the sweep contribution over the permeation process. The fitted model allowed the importance of the dilutive and sweep effect over the oxygen permeation. Although the sweep effect present lower influence in the oxygen transport across the membrane, its effect prevents concentration polarization limitations. Modelling the protonic cell based electrolysis allowed to study the effect of the scale up in this process and to evaluate the efficiency in the energy storing in form of hydrogen. Modelling protonic membrane reformer allowed checking the thermal microintegration of all the heats which take place in the setup. The electrocompression of hydrogen is an isothermal phenomenon which releases the demanded energy as heat. The model allowed to check the coarsening of the Ni particles does not limit the hydrogen extraction for the studied cell. A final model was built to study a catalytic membrane reactor for the methane dehydroaromatization using co-ionic conducting cells. The model was validated using experimental data. Additionally, different studies were performed to analyze possible limitation in the process. Results show that there are no hydrogen diffusion limitations in this process. Additionally, the shift of the equilibrium by extracting hydrogen has to be stopped because kinetic limitations. / Catalán Martínez, D. (2019). Development of electrocatalytic layers and thermo-fluid dynamic evaluation for high temperature membrane reactors [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/135278 / TESIS

Les micropolluants d'origine pharmaceutique tels que les antibiotiques, les hormones, les anti-inflammatoires ou les médicaments anticancéreux sont généralement réfractaires aux procédés classiques de traitement des eaux et leur rejet dans l'environnement même à l'état de traces (< µg/L) pose de réels problèmes environnementaux et de santé publique. Le traitement de ces effluents par voie enzymatique semble être une alternative intéressante et ce d'autant plus si le biocatalyseur est immobilisé directement à la surface d'une membrane afin d'améliorer sa stabilité et permettre sa réutilisation. Le travail à réaliser dans le cadre de cette thèse vise la conception et l'optimisation de bioréacteurs destinés à la dégradation de micropolluants ciblés. Réalisé dans le cadre d'un contrat Européen (ENDETECH), ce travail est une collaboration avec d'autres équipes de recherche européennes en charge de sélectionner les biocatalyseurs et de mettre au point les méthodes analytiques de détection et de caractérisation des produits de la réaction. / Pharmaceutical micropollutants such as antibiotics, hormones, anti-inflammatory or anti-cancer drugs are usually reluctant to conventional wastewater treatment processes and their disposal in the environment, even at low concentrations (< µg/L) may have an impact on human health. The enzymatic treatment of these effluents seems a promising alternative if the biocatalyst is immobilized on a membrane to enhance its stability and to enable its reuse. This thesis work aims at designing and optimizing bioreactors for micropollutants degradation. It is a collaboration (ENDETECH project) with other European research teams in charge of selecting the biocatalysts and developing analytical methods for the detection and characterization of transformation products.

No / Oxidative coupling of methane (OCM) is suggested to be a promising process for the conversion of the abundant natural gas into useful chemicals. However, this reaction faces many drawbacks such as low yields for higher hydrocarbons, fast catalyst deactivation, and huge heat effects of the reaction. Only a well-designed fluidized bed reactor is able to overcome effectively those disadvantages and to provide a satisfactory continuous operation. However, design approaches for fluidized bed reactors are still based on models developed during 70s and 80s, which cannot take into account various hydrodynamic effects on the reactor performance. Thus, a reactor designer has usually to rely on extensive experiments in order to improve the classical fluidized bed reactor design. In this work, the relevance of hydrodynamics, reactor geometry, and feeding policy on the performance of a fluidized bed reactor for the OCM is shown. For this purpose, several case studies of fluidized bed reactors are simulated in full 3D geometry under the same reaction conditions, but with different reactor geometries and feeding policy. These studies show the significance of hydrodynamic parameters for the reactor performance, and moreover, how fluidized bed reactor performance can be improved by a careful study of coupled momentum-mass transport-reaction phenomena. Furthermore, it can be demonstrated that a suitable distributed feeding policy of oxygen provides an improved yield while a traditional fluidized bed reactor design results in an inferior performance among all investigated cases.

Biocatalytic membrane reactors combine the highly efficient biotransformation capability of enzymes with the selective filtration performance of membrane filters. Common strategies to immobilize enzymes on polymeric membranes are based on chemical coupling reactions. Still, they are associated with drawbacks such as long reaction times, high costs, and the use of potentially toxic or hazardous reagents. In this study, a reagent-free immobilization method based on electron beam irradiation was investigated, which allows much faster, cleaner, and cheaper fabrication of enzyme membrane reactors. Two industrial lipase enzymes were coupled onto a polyvinylidene fluoride (PVDF) flat sheet membrane to create self-cleaning surfaces. The response surface methodology (RSM) in the design-of-experiments approach was applied to investigate the effects of three numerical factors on enzyme activity, yielding a maximum activity of 823 118 U m2 (enzyme concentration: 8.4 g L1, impregnation time: 5 min, irradiation dose: 80 kGy). The lipolytic membranes were used in fouling tests with olive oil (1 g L1 in 2 mM sodium dodecyl sulfate), resulting in 100% regeneration of filtration performance after 3 h of self-cleaning in an aqueous buffer (pH 8, 37 C). Reusability with three consecutive cycles demonstrates regeneration of 95%. Comprehensive membrane characterization was performed by determining enzyme kinetic parameters, permeance monitoring, X-ray photoelectron spectroscopy, FTIR spectroscopy, scanning electron microscopy, and zeta potential, as well as water contact angle measurements.

This thesis describes a new technique for the preparation of ultrathin Pd based membranes supported on a hollow-fiber α-alumina substrate for H₂ separation. The effectiveness of the membranes is demonstrated in the ethanol steam reforming (EtOH SR) reaction in a membrane reactor (MR) for H₂ production. The membrane preparation technique uses an electric-field to uniformly deposit Pd nanoparticle seeds on a substrate followed by deposition of Pd or Pd-Cu layers on the activated surface by electroless plating (ELP). The well distributed Pd nanoparticles allow for enhanced bonding between the selective layer and the substrate and the formation of gas tight and thermally stable Pd or Pd-Cu layers as thin as 1 µm, which is a record in the field. The best Pd membrane showed H₂ permeance as high as 5.0 × 10⁶ mol m²s⁻¹Pa⁻¹ and stable H²/N₂ selectivity of 9000 - 7000 at 733 K for 5 days. The Pd-Cu alloy membrane showed H₂ permeance of 2.5 × 10⁶ mol m⁻²s⁻¹Pa⁻¹ and H₂/N₂ selectivity of 970 at the same conditions. The reaction studies were carried out with a Co-Na/ZnO catalyst both in a packed bed reactor (PBR) and in a MR equipped with the Pd or Pd-Cu membrane to evaluate the benefits of employing membranes. For all studies, ethanol conversion and hydrogen product yields were significantly higher in the MRs compared to the PBR. Average ethanol conversion enhancement and hydrogen molar flow enhancement were measured to be 12 % and 11 % in the Pd MR and 22 % and 19 % in the Pd-Cu MR, respectively. These enhancements of the conversion and product yield can be attributed to the shift in reaction equilibria by continuous hydrogen removal by the Pd based membranes. The comparative low enhancement in the Pd MR was found to be the result of significant contamination of Pd layer by CO or carbon compounds deposition during the reaction. A one-dimensional modeling of the MR and the PBR was conducted using identical conditions and their performances were compared with the values obtained from the experimental study. The model was developed using a simplified power law and the predicted values matched experimental data with only minor deviations indicating that the model was capturing the essential physicochemical behavior of the system. Enhancements of ethanol conversion and hydrogen yield were observed to increase with rise in space velocity (SV), which could be explained by the increase in H₂ flux through the membranes with SV in the MRs. / Ph. D.