Search

This work aims to evaluate the dynamic performance of a highly selective Ni-based surface during the oxidative dehydrogenation of ethane (ODH-C2). The catalyst comprises an in-house bimetallic mixed-oxide formulation with a Ni/Sn atomic ratio of 10. To corroborate its proper synthesis, it is characterized by TGA, AES, XRD, physisorption of N2 and TEM. The catalytic evaluation of the mixed oxide under dynamic conditions allows the proposition of a redox surface mechanism whose reliability is evaluated through a rigorous analysis, which is based on the development of a kinetic model and a robust experimentation program using a fully-automated micro-reaction unit and registering in-situ surface temperatures and continuous inline monitoring of oxygen and carbon dioxide. Experiments are carried out using a mixture of ethane or ethylene, oxygen and nitrogen as feedstock, at temperatures from 360 to 480 °C, total pressures from 100 to 500 kPa, and space-time values from 8.1 to 133.1 kgcat s molC2H6−1. Oxygen conversion ranges from 5% to 100% while the one for ethane varies from 5% to 60%. Besides, the selectivity and yield to ethylene vary from 30% to 90% and from 2% to 40%, respectively. The suitability of the redox mechanism is here assessed by evaluating statistical and phenomenological foundations, including Boudart’s criteria. Kinetic parameters, estimated by non-linear regression and using the reparametrized form of the Arrhenius and van’t Hoff equations, are phenomenologically well founded, such that changes of entropy and enthalpy of adsorption correctly describe the loss of mobility due to adsorption and the exothermic nature of the adsorption processes. Ethylene formation is the reaction demanding the lowest activation energy (Ea1 = 61.94 kJ mol−1), while the total oxidation of ethane is the path requiring the largest activation energy (Ea2 = 132.6 kJ mol−1). Concerning the adsorption enthalpy, ethylene exhibits the largest value ( − Δ H C 2 H 4 ° = 123.39 kJ mol−1), while carbon dioxide presents the lowest one ( − Δ H C O 2 ° = 42.00 kJ mol−1). Additional findings can be summarized as follows: activity and selectivity are recovered after the dynamic operation under oxidative conditions of the catalytic surface; carbon dioxide is identified as the only no desired byproduct; and hydroxyl surface species lead to the formation of water which affects the selectivity to ethylene, as well as the reaction rates. These findings are of interest for future studies directed at elucidating the performance of the Ni-based catalyst at larger scales, paving the way for the efficient design of the industrial reactor for the ODH-C2.

Ethane oxidative dehydrogenation (ODH-C2) is a promising alternative for producing ethylene. Even if SnO2-NiO catalysts are characterized by their long-term stability and high selectivity to ethylene, their kinetic performance has not been investigated in detail yet. In this work, three kinetic models were developed according to redox mechanisms, without assuming a single rate-determining step, for evaluating the ODH-C2 kinetics over an in-house synthesized SnO2-NiO catalyst. Reaction mechanism proposals were based on detailed catalyst characterization (XRD, physisorption of N2, XPS, O2-TPIE, NH3-TPD, H2-TPR, and SEM-EDX) and robust experimental evaluation of the material. Experiments were performed in the kinetic control regime in a micro-reaction unit at temperatures between 360 and 480 degrees C, inlet oxygen partial pressures between 2 and 15 kPa, inlet ethane partial pressures between 3 and 10 kPa and space times between 9.4 and 45.5 kgcat s molC2H6-1. In a set of additional experiments, feeding ethylene instead of ethane, the conversion ranged from 1.5 to 14% and CO2 was the only reaction product. Physicochemical and statistical criteria were employed to discriminate between the performance of the considered redox mechanisms. In analyzing the kinetic results, it was found that: outlet molar flow rates were better fitted by the redox mechanism not accounting for the chemisorption of hydrocarbon-based molecules and considering the adsorption of oxygen species on active sites rather than their insertion into the lattice; water was the component with the highest affinity on the active sites; and ethylene and carbon dioxide production is associated with activation energies ranging from 66-94 kJ mol-1 and 80.0-113.0 kJ mol-1, respectively. These findings contribute to the mechanistic understanding of ODH-C2 and provide a reliable model for the future design and scale-up of the process.

This work aims at assessing the hydrodeoxygenation (HDO) of phenol over a promising catalytic material: a CoMoS-based active phase with a Co/(Co + Mo) = 0.2, supported on a promising mixed oxide, Al2O3-TiO2 (Al/Ti = 2). Particularly, to optimize the catalytic and kinetic performance of CoMoS/Al2O3-TiO2, a response surface methodology (RSM) is carried out by following a Box–Behnken experimental design. The response variables are the initial reaction rate and the reaction selectivity, determined via a proper contribution analysis (𝜑) of both the direct hydrodeoxygenation (DDO) and the hydrogenation (HYD). At the same time, the operating conditions used as factors are the reaction temperature (280–360 °C), the total pressure (3–5.5 MPa), and the Mo loading (10–15 wt.%). The activity and selectivity are correlated to the catalysts’ physicochemical properties determined by XRD, UV-Vis DRS, TPR, and Raman Spectroscopy. Regarding the CoMo-based active phase, a Mo loading of 12.5 wt.% leads to the optimal reaction performance, which is associated with the lowest (Co + Mo)oh/(Co + Mo)th ratio. Concerning the operating conditions, a temperature of 360 °C and a total pressure of 5.5 MPa give rise to the optimal initial reaction rates, in which the DDO (𝜑 = 65%) is selectively favored over HYD (𝜑 = 35%).

International audience; The production of 2-phenylethanol (2-PE), a high-valued aroma, has been performed naturally through the bioconversion of Lphenylalanine by the Ehrlich pathway in yeast. Nevertheless, one of the main limitations of this bioconversion is the inhibition of yeast growth by 2-PE. This work evaluated the intensification of 2-PE production in a batch culture using a conventional bioreactor coupled to an in-situ product removal (ISPR) process, by means of membrane-based solvent extraction (MBSE). The culture of the native yeast Kluyveromyces marxianus ITD0090, using a shaker flask stirred at 150 rpm, produced a maximum concentration of 2-PE of 0.7 g L −1 after 24 hours. When the yeast was cultivated in a controlled aerated-stirred bioreactor operated at 0.8 vvm and 350 rpm, the maximum production of 2-PE after 48 h reached 1.49 g L −1. Intensification of the bioprocess was achieved by coupling the controlled bioreactor with a MBSE system, which allowed the continuous recovery of the 2-PE produced, reaching a final titre of 3.02 g L −1 after 56 h.

Degradation of a dye in water alone or as part of a mixture was studied under different advanced oxidation processes in order to elucidate possible competition or interference between dyes. For thi...

The dry reforming of methane is a promising technology for the abatement of CH4 and CO2. Solid solution Ni–La oxide catalysts are characterized by their long–term stability (100h) when tested at full conversion. The kinetics of dry reforming over this type of catalysts has been studied using both power law and Langmuir–Hinshelwood based approaches. However, these studies typically deal with fitting the net CH4 rate hence disregarding competing and parallel surface processes and the different possible configurations of the active surface. In this work, we synthesized a solid solution Ni–La oxide catalyst and tested six Langmuir–Hinshelwood mechanisms considering both single and dual active sites for assessing the kinetics of dry reforming and the competing reverse water gas shift reaction and investigated the performance of the derived kinetic models. In doing this, it was found that: (1) all the net rates were better fitted by a single–site model that considered that the first C–H bond cleavage in methane occurred over a metal−oxygen pair site; (2) this model predicted the existence of a nearly saturated nickel surface with chemisorbed oxygen adatoms derived from the dissociation of CO2; (3) the dissociation of CO2 can either be an inhibitory or an irrelevant step, and it can also modify the apparent activation energy for CH4 activation. These findings contribute to a better understanding of the dry reforming reaction's kinetics and provide a robust kinetic model for the design and scale–up of the process.

El 10-15 % de los tumores renales son tipo papilar, su asociacion a sindromes hereditarios es poco frecuente y son muy agresivos. Se presenta el caso de un paciente con piloleiomiomatosis con tumor dependiente del rinon derecho y la glandula suprarrenal izquierda, y nefrectomia radical derecha con carcinoma renal papilar tipo 2. Recurrencia retroperitoneal, hepatica y lesion testicular bilateral. Orquiectomia radical izquierda con tumor de celulas de Leydig, metastasectomia hepatica y retroperitoneal con carcinoma papilar tipo 2, ultimo estudio de seguimiento sin datos de actividad tumoral. el seguimiento oncologico con estudios no invasivos y los avances terapeuticos pueden mejorar las tasas de supervivencia. 10-15% of cases of renal tumors correspond to papillary type, the association to hereditary syndromes is rare, and aggressive. Clinical case: male with a history of piloleiomyomatosis and right kidney and left adrenal tumor, right radical nephrectomy with papillary renal carcinoma type 2. Development retroperitoneal, hepatic and bilateral testicular tumor. Left radical orchiectomy with Leydig cell tumor, hepatic and retroperitoneal metastasectomy with papillary carcinoma metastasis type 2, latest follow-up study without tumor activity. Oncological follow-up with non-invasive studies and therapeutic advances could improve survival rates.

Las metástasis de mama a uréter son extremadamente raras y la mayoría son asintomáticas.Mujer de 67 años, con cáncer de mama derecha EC IA luminal A de 5 años de evolución. Presentó infección de vías urinarias de repetición, hematuria macroscópica total y dolor renal derecho. La tomografía abdominopélvica mostró dilatación del cáliz superior y defecto de llenado en la pelvis renal derechos. Se le realizó nefroureterectomía radical derecha, rodete vesical. El reporte histopatológico fue metástasis de carcinoma infiltrante con afectación de pelvis renal y uréter.La metástasis tardía del cáncer de mama al uréter y la pelvis es rara.Breast metastases to ureter are extremely rare. Most are asymptomatic.A 67-year-old woman with 5 years of evolution, with right breast cancer stage IA luminal A. She presented repeated urinary tract infection, total macroscopic hematuria and pain in the right renal fossa. The computed tomography showed dilation of the upper calyx and filling defect in the renal pelvis. A right laparoscopic radical nephroureterectomy was realized; the histopathological report was metastasis of infiltrating carcinoma without specific pattern involving renal pelvis and ureter.Late metastasis of breast cancer to ureter and pelvis are rare.

Antecedentes Las metastasis de mama a ureter son extremadamente raras y la mayoria son asintomaticas. Caso clinico Mujer de 67 anos, con cancer de mama derecha EC IA luminal A de 5 anos de evolucion. Presento infeccion de vias urinarias de repeticion, hematuria macroscopica total y dolor renal derecho. La tomografia abdominopelvica mostro dilatacion del caliz superior y defecto de llenado en la pelvis renal derechos. Se le realizo nefroureterectomia radical derecha, rodete vesical. El reporte histopatologico fue metastasis de carcinoma infiltrante con afectacion de pelvis renal y ureter. Conclusiones La metastasis tardia del cancer de mama al ureter y la pelvis es rara. Background Breast metastases to ureter are extremely rare. Most are asymptomatic. Case report A 67-year-old woman with 5 years of evolution, with right breast cancer stage IA luminal A. She presented repeated urinary tract infection, total macroscopic hematuria and pain in the right renal fossa. The computed tomography showed dilation of the upper calyx and filling defect in the renal pelvis. A right laparoscopic radical nephroureterectomy was realized; the histopathological report was metastasis of infiltrating carcinoma without specific pattern involving renal pelvis and ureter. Conclusions Late metastasis of breast cancer to ureter and pelvis are rare.

This research frames a novel approach to develop a pseudo-continuous model for describing the dynamics of a Newtonian fluid in an industrial-scale packed-bed reactor presenting a low tube to particle diameter ratio ( d t / d p = 3.048 ) at particle Reynolds numbers ranging from 750 to 1750. The model accounts for the effect of compressional work on the pressure drop and the velocity field. The development of the pseudo-continuous model uses pseudo-steady-state local information obtained from Direct Numerical Simulations (DNS) to determine the so-called fluid dynamic descriptors. The suitability of the geometry configuration, determined from rigid body dynamic calculations, and particle-resolved simulations (PRS) is assessed by describing pressure drop observations and analyzing void fraction and velocity predictions. Local information related to the apparent permeability allows the development of a modified correlation to quantify solid–fluid frictional mechanisms. The pseudo-continuous model, developed by quantifying solid–fluid interactions with the use of either local information or the modified correlation, is able to describe properly velocity profiles obtained out of PRS. Velocity profiles predicted by the pseudo-continuous model are in agreement with those simulated by the Navier–Stokes-Darcy-Forchheimer equations. The density field and the divergence of the velocity field elucidate how fluid dynamics, along with the pressure drop, is affected by the fluid compressibility. The approach described here can be extended to complex pellet shapes, including the development of pseudo-continuous models for heat and mass transport, paving the way for the design of more efficient industrial-scale packed-bed reactors.

Steam cracking of diverse hydrocarbon sources is nowadays the main technology used to produce ethene worldwide, however, it presents energetic and environmental limitations related to the large con...

The conceptual design of a four-phase partitioning bioreactor to produce (+)-nootkatone out of (+)-valencene on whole cells of Yarrowia lipolytica 2.2ab requires yet from the proper modelling and analysis of those phenomena limiting the bioconversion in this reaction system. This work is aimed at modelling this partitioning bioreactor. In this sense, a pseudo heterogeneous model is, particularly, developed by using experiments under biotic and abiotic conditions. First, in a two-phase abiotic reactor, interfacial mass transfer in absence of reaction is characterized by determining the effective interfacial coefficients for sequiterpenes ( k i A dp ) and for oxygen ( K L a ). Then, kinetics and cell deactivation are characterized by developing the corresponding models in a three-phase biotic reactor; two types of whole cells are evaluated here, namely Yarrowia lipolytica 2.2ab untreated and treated with cetyl trimethylammonium bromite (CTAB) to expel possible reaction intermediate out of the cell and with niacin (vitamin B 3 ) to favour the regeneration of the cofactor nicotinamide adenine dinucleotide phosphate (NADPH + ). It is worth stressing that kinetic and cell deactivation models account for (+)-valencene inhibition, (+)-nootkatone inhibition and oxygen inactivation. To this end, the partitioning four-phase reactor model, making use of the calculated mass transport, kinetic and deactivation parameters, is able to describe observations and predict enzyme coverage profiles at different cell activity scenarios. A parametric sensitivity study allows the identification of volume disperse phase fraction ( ϕ = 0.2–0.5), agitation rate (200–400 rpm) and airflow rate (0.5–1 vvm) as the main operational variables influencing the biological conversion of (+)-valencene. At studied conditions, the highest production rate of (+)-nootkatone is obtained at 300 rpm, 1 vvm and, essentially, at ϕ = 0.35.

The inclusion of radiative transfer phenomena during the scale-up of photocatalytic reactions is of utmost importance. Photocatalyst optical transport properties change with any factor affecting agglomeration, such as pH, hydrodynamics, agitation, or reaction extent. Hence, photocatalytic reaction engineering needs fast and straightforward methodologies that allow the in-situ estimation of photocatalyst optical properties. Along this line, the present work presents a specially designed system compatible with any photocatalytic reaction system. The proposed set-up allows the estimation of the extinction coefficient via spectrophotometric procedures. It also enables measurements of laterally scattered radiation, allowing (with a numerical integration procedure) the independent estimation of the single-particle albedo and the phase function considered. The methodology avoids using a nephelometer and an integrating sphere. Instead, it uses a single prototype that allows the fast determination of optical parameters directly in the reaction set-up. The methodology proposed is used to obtain the optical transport properties for Titanium Dioxide under visible light (β* = 0.78 ± 0.04 ppm−1m−1, γ = 0.92 ± 0.08, g = 0.76 ± 0.08) and under UV light (β* = 3.90 ± 0.30 ppm−1m−1, γ = 0.83 ± 0.03, g = 0.89 ± 0.09) and Graphene Oxide under visible light (β* = 0.36 ± 0.04 ppm−1m−1, γ = 0.135 ± 0.014, g = 0.12 ± 0.01).

Flavonoids are known as natural soft drugs that have biological activities and applications in the pharmaceutical industry. These include antioxidant, antiinflammatory, anticarcinogenic, antimicrobial, and antiviral activities, among others (Ribeiro et al., 2008; Karabin et al., 2015). The flavonoids are a group of phenolic compounds with structures comprising three rings, having antioxidant activities. Two of the rings are benzenes connected by a pyrone ring that has an oxygen atom. It is the structure of the last ring which permits their classification into six subclasses: flavons, flavonols, flavonons, flavanols (catechins), anthocyanins, and isoflavonoids (Zhang, 2007). Hydroxylation or methoxylation of flavones increases their antioxidant properties and reduces their low-density lipoproteins (Morin et al., 2008). Natural synthesis of flavonoids is only carried out in plants. Due to its importance in terms of functionality, it has been discovered that their biological activities can be enhanced by hydroxylation or methylation; these enhanced properties can be obtained through bioconversion processes using enzymes or whole cells. Ullrich and Hofrichter (2007) reviewed the enhancement of biological activities of flavonoids by the selective hydroxylation of aromatic compounds, one of the most challenging chemical reactions in synthetic chemistry, using isolated enzymes or whole microbial cells. They gave an overview of the different enzymes and mechanisms used to introduce oxygen atoms into aromatic molecules. Several enzymes have been used to enrich flavonoids. One example is the use of monooxygenases. These are enzymes that incorporate one hydroxyl group into a substrate. One such monooxygenase, cytochrome P450 105D7 from Streptomyces avermitilis, can catalyze the hydroxylation of two flavanones—naringenin and pinocembrin (Liu et al., 2016). The unique catalytic properties of oxygenases have undoubted biosynthetic value (Duetz et al., 2001). Prasetyo et al. (2011) carried out the enrichment of naringenin with simple phenolic compounds, rich in hydroxyl or methoxy groups, using laccases to enhance its antioxidant activity. In oxidative enzymatic reactions where cofactor regeneration is needed, with high regioselectivity and stereoselectivity, whole-cell bioconversion is an attractive and economic alternative to the cell-free enzyme system (Carvalho, 2016). Holland and Weber (2000) examined the manipulation of microbial hydroxylating enzymes, in both whole-cell and cell-free environments, in the context of controlling the regioselectivity and stereoselectivity of the hydroxylation reaction. Kitamura et al. (2013) reported the bioconversion of flavonoids (flavonons, isoflavons, and chalcons) to their corresponding hydroxylated products using recombinant cells of Escherichia coli, with expression of the monooxygenase enzyme cytochrome P450 BM3. An increase in antioxidant activity in some of the products was observed. However, a deep review of the kinetics and engineering might be helpful to analyze and stimulate discussion about the potential of the whole-cell bioconversion of flavonoids. Therefore the aim of this chapter is to analyze and discuss the potential of the whole-cell bioconversion of flavonoids as an attractive alternative for enhancing their biological properties.

In addition to research on the chemical properties of natural aroma compounds (NACs) that cause the perception of flavour and aroma, several studies have reported their potential applications for human health due to their antioxidant, anti-inflammatory, anti-cancer and anti-obesity properties. Furthermore, consumer demand shows a tendency towards natural products; most research in the industry and academic fields has focused on the bio-generation of commercially relevant NACs, particularly microbial production via de novo synthesis or biotransformation using enzymes or whole cells in conventional aqueous media. However, most of the attractive industrial substrates are insoluble or poorly water-soluble during their biocatalytic transformation in aqueous media, as the thermodynamic equilibrium favours the hydrolysis rather than the synthesis of NACs, thus limiting the industrial applications. As a promising alternative, solid/gas biocatalysis (SGB) uses catalytic enzyme activity to react with the substrates in the gas phase, minimising the thermodynamic constraints and offering technological, environmental and economic advantages. SGB provides biocatalyst stability, reduces mass transfer resistance, provides eco-friendly product recovery, includes important engineering aspects in the design, and allows for the optimisation and intensification of any bioprocess. This review aims to analyse the potential, technical and engineering aspects of SGB as an alternative white biotechnology process for the biocatalytic conversion of NACs with applications for human health and wellness.

The oxidation of (+)-valencene on Yarrowia lipolytica 2.2ab in a three-phase partitioning bioreactor using orange essential oil is a promising technology to market natural (+)-nootkatone overcoming both substrate and product inhibitions. The adequate determination and selection of thermodynamic, kinetic, deactivation, hydraulic and mass transport parameters are essential to perform a suitable strategy of scaling-up. This study is aimed at determining these parameters to identify through a regime analysis the mechanisms limiting the bioconversion process. The volumetric oxygen transfer coefficient ( k L a ) and the Sauter mean drop diameter ( d 32 ) values ranged from 10 to 116 h −1 and 8 to 18 μm, respectively. The substrate ( k S ) and product ( k P ) global interfacial mass transfer coefficients were determined from a modified Lewis cell. The k S and k P values ranged from 0.6 to 3.0 × 10 −5 and 2 to 3 × 10 −5 m s −1 , respectively. Finally, a kinetic model, considering a bi-substrate reaction and accounting for cell deactivation, was developed. The affinity constants for oxygen and (+)-valencene were K O2 = 7.11 × 10 −2 mg O2 L −1 and K S = 7.865 × 10 −3 mg S L −1 , respectively, while catalytic constant related to (+)-nootkatone formation was k cat = 5.025 × 10 3 mgP mg E −1 h −1 . Thus, the regime analysis in terms of the characteristic times suggested that kinetics, namely the consumption rate of (+)-valencene was the main mechanism limiting the bioconversion process.

This study is aimed at giving some insights on kinetics, adsorption and partitioning of ethyl acetate during a single well tracer test. Synthetic formation water, an specific crude oil and a silicate-dolomite rock were used during experiments performed in laboratory and bench scale systems. Independent sets of experiments were designed to calculate the partition coefficient of ethyl acetate between the formation water and the oil, to develop a kinetic model for the hydrolysis of ethyl acetate, and to derive isotherm and kinetic models for the adsorption of ethyl acetate on the rock. These tracer experiments were evaluated at a concentration range (100–300 mmol.L−1) similar to that supposed to be used in the single well tracer method. All parameters determined from these experiments were validated describing observations from stirred batch and column systems, in which kinetic, adsorption and partitioning phenomena occurred at the same time. Pseudo-heterogeneous models, accounting for three phases namely the formation water, the rock and the oil, were applied to elucidate the interaction of the different mechanisms involved in these set-ups. Main results are summarized as follows: (i) partition coefficients (K EA) were apparent varying from ca. 5–8 because of thermodynamic constraints; (ii) kinetic models for the hydrolysis of ethyl acetate were developed under acid and basic conditions since at neutral ones there were negligible conversions; (iii) the combined Langmuir-Freundlich isotherm and the Langmuir kinetics were the most suitable models describing equilibrium and adsorption rate observations, respectively; (iv) the studied rock adsorbed significant amounts of ethyl acetate, leading to a maximum adsorption capacity (qEAm) of ca. 7.0 mmol.g−1 at studied operating conditions; (v) the adsorption kinetic model rather than the simplified isotherm model seems necessary to describe this phenomenon from the single well test evaluating ethyl acetate as the tracer; and (vi) partition, hydrolysis and adsorption parameters evaluated from independent experiments allowed us to describe observations from both stirred batch and column systems. These results disclose the importance of accounting for partition, hydrolysis and adsorption mechanisms in a single well method using ethyl acetate as the tracer.

Super acidic nanostructured sulfated aluminum-zirconium binary oxides in mole ratios of Zr4+: Al3+ as 2:1 (SAZ-1), 1:1 (SAZ-2), 1:2(SAZ-3) and the reference catalyst super acidic sulfated zirconia (SZ) were synthesized by a precipitation method. Firstly, the catalytic performance of these four catalysts was evaluated during the isomerization of n-hexane to 2-methyl pentane and 3-methyl pentane, n-heptane and n-octane to their corresponding branched chain isomers at low temperature and pressure conditions (40°C and 1 atm). SAZ-1 performed the highest active and selective isomerization of n-hexane, n-heptane, and n-octane into their corresponding branched chain isomers. The catalytic activity of the reference catalyst SZ was the lowest among the four synthesized catalysts. TEM analysis applied to SAZ-1 and SZ indicated the presence of particle-bulks having average size of 20 nm; moreover, these materials presented an amorphous nature, having no particular surface morphology. XRD confirmed the amorphous structure of SAZ-1 and SZ as well as indicated their internal phase structure. FTIR generated ideas about different linkages and bond connectivities between atoms and groups in SAZ-1 and SZ. Ammonia-TPD of these two materials confirmed the higher super acidic nature of SAZ-1 and lower super acidic nature of SZ. Catalyst evaluation and characterization allowed to propose a reaction mechanism, elucidating a possible role of Brønsted and Lewis acid sites on the studied reaction-catalyst, being the former active sites the main factor leading to isomerization reaction. AFM and SEM pictures indicated the nature of the surface of the catalysts. Nevertheless, SEM analysis before and after the reaction displayed that catalyst morphology was modified and could influence the activity of the catalyst. The use of SAZ-1 is cost saving as well as energy saving.

The hydrodesulfurization (HDS) of dibenzothiophene (DBT) is investigated over a commercial NiMoP/γ-Al2O3 catalyst in a micro trickled bed reactor (Micro-TBR) at operating conditions of a reactive distillation (RD) column. An analysis with and without reaction is carried out to have a first understanding on the complex interaction between kinetics and transport phenomena. A set of well-accepted criteria is evaluated to elucidate the presence of heat and mass transport limitations. Residence time distribution (RTD) experiments are performed to evaluate axial dispersion through the estimation of axial dispersion coefficient (Daxial,L) from a convection-dispersion model. Experiments with reaction are carried out using hydrogen and DBT as feedstock at reaction temperatures from 533 to 599 K, pressures from 1.5 to 2.5 MPa and inlet molar flow of DBT from 4 to 12×10–8 mol.s–1. A pseudo heterogeneous model accounting for mass transport limitations is used to describe experiments under reaction conditions. The main findings can be summarized as follows: most of RD operating conditions lead to the presence of interfacial mass transport limitations at both interfaces L-S and G-L; convection-dispersion model is able to describe satisfactorily RTD observations, suggesting that axial dispersion phenomena are negligible; conversion of DBT ranges from ca. 22 to 90% having a selectivity to by-product molecules from 30 to 80%, respectively; and the pseudo heterogeneous reaction model describes observations adequately obtaining activation energies ranging from 49 to 62 kJ mol–1 at pressures from 1.5 to 2.5 MPa, respectively. Estimated activation energies are comparatively lower than the activation energies reported in literature for the conventional HDS process, i.e. 40–160 kJ.mol–1, thereby suggesting an apparent catalytic energy savings by using RD technology.

A systematic theoretical study on graphene oxide model systems was performed with Density Functional Theory (DFT), and supported by experimental evidence. The results revealed that graphene is highly susceptible to be decorated with organic functional groups, which induced the formation of a band gap, and the rising of a novel semiconducting character. This novel property was used to explore the possible photocatalytic potential in the model systems under study. That is, we evaluated work functions to theoretically obtain the energies of the valence band maximum and the conduction band minimum with respect to the normal hydrogen electrode potential. The assessment of UV-vis profile via Time-dependent DFT also showed the potential of the model systems to efficiently absorb sun light irradiation under photocatalytic conditions. Moreover, the results showed that it is possible to tune the photocatalytic potential of the graphene oxide models under study by interchanging the functional groups anchored on the graphene surface, and their corresponding contents ratio. Experimental evidence obtained via the measurement of optoelectronic properties, revealed that it is possible to classify a graphene oxide powder into one of the model systems under study, while a photocatalytic procedure performed in our laboratory, showed the facile photoreduction of formic acid into methanol with such a graphene oxide. Consequently, the prediction of the electronic structure properties is expected. This may represent a tool to design materials based on graphene oxide to be implemented in reactors for photocatalytic applications.

This is a theoretical study about the influence of turbulence on momentum and heat transport in a packed-bed with low tube to particle diameter ratio. The hydrodynamics is given here by the time-averaged Navier-Stokes equations including Darcy and Forchheimer terms, plus a κ-ε two-equation model to describe a 2D pseudo-homogeneous medium. For comparison, an equivalent conventional flow model has also been tested. Both models are coupled to a heat transport equation and they are solved using spatial discretization with orthogonal collocation, while the time derivative is discretized by an implicit Euler scheme. We compared the prediction of radial and axial temperature observations from a packed-bed at particle Reynolds numbers (Rep) of 630, 767, and 1000. The conventional flow model uses effective heat transport parameters: wall heat transfer coefficient (hw) and thermal conductivity (keff), whereas the turbulent flow model includes a turbulent thermal conductivity (kt), estimating hw via least-squares with Levenberg-Marquardt method. Although predictions of axial and radial measured temperature profiles with both models show small differences, the calculated radial profiles of the axial velocity component are very different. We demonstrate that the model that includes turbulence compares well with mass flux measurements at the packed-bed inlet, yielding an error of 0.77 % in mass flux balance at Rep = 630. We suggest that this approach can be used efficiently for the hydrodynamics characterization and design and scale-up of packed beds with low tube to particle diameter ratio in several industrial applications.

Lithium-ion batteries (LiBs) have gained a worldwide position as energy storage devices due to their high energy density, power density and cycle life. Nevertheless, these performance parameters are yet insufficient for current and future demands diversifying their range of applications, and competitiveness against other power sources. In line with the materials science, the optimization of LiBs, first, requires an in-depth characterization and understanding of their determining steps regarding transport phenomena and electrode kinetics occurring within these devices. Experimental and theoretical studies have identified the solid-state diffusion of Li+into the composite cathode material as one of the transport mechanisms limiting the performance of LiBs, in particular at high charge and discharge rates (C-rates). Nowadays, there is however ambivalence to characterize this mass transport mechanism using the diffusion coefficient calculated either by electrochemical techniques orab initioquantum chemistry methods. This contribution revisits conventional electrochemical methodologies employed in literature to estimate mass transport diffusivity of LiBs, in particular using LiFePO4in the cathode, and their suitability and reliability are comprehensively discussed. These experimental and theoretical methods include Galvanostatic and Potentiostatic Intermittent Titration Technique (GITT and PITT), Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV) andab initioquantum chemistry methods. On the one hand, experimental methods seem not to isolate the diffusion mechanism in the solid phase; thus, obtaining an unreliable apparent diffusion coefficient (ranging from 10–10to 10–16 cm2 s−1), which only serves as a criterion to discard among a set of LiBs. On the other hand, atomistic approaches based onab initio, density functional theory (DFT), cannot yet capture the complexity of the local environments involved at this scale; in consequence, these approaches have predicted inadequate diffusion coefficients for LiFePO4(ranging from 10–6to 10–7 cm2 s−1) which strongly differ from experimental values. This contribution, at long last, remarks the factors influencing diffusion mechanisms and addresses the uncertainties to characterize this transport mechanism in the cathode, stressing the needs to establish methods to determine the diffusion coefficient accurately, coupling electrochemical techniques,ab initiomethods, and engineering approaches based on modeling.

The aim of this work was to experimentally and theoretically evaluate the performance of four ionic liquids (ILs) used in the three-phase (air–water–IL) partitioning bioreactor (TPPB) for the production of bicyclic lactone (1S,5R)-2-oxabicyclo[3.3.0]oct-6-en-3-one from bicyclic ketone bicyclo[3.2.0]hept-2-en-6-one over Escherichia coli strain TOP10 pQR239. In particular, partition coefficients of the substrate and product, mass-transfer coefficients of the substrate, product and oxygen, as well as the deactivation parameters related to the loss of cell viability, owing to the presence of the IL, were determined. To the best of our knowledge, cell viability was described, for the first time, using a power law equation model. The operation of the biphasic system without inhibitory conditions led to a substrate conversion of 100%, whereas the conversion was approximately 25% under inhibitory conditions. Besides, when the IL was used as the dispersed phase in the TPPB, the substrate conversion under inhibitory conditions was between 20% and 85%. All evaluated ILs were thermodynamically suitable for use as the dispersed phase; however, all of them provoked a loss in cell viability. When trioctylmethylammonium bis (trifluoromethylsulfonyl)imide [OMA][BTA] was used in the three-phase system, the highest substrate conversion (ca. 85%) and the lowest loss of cell viability (ca. 55%) were observed, even though this IL presented lower partition coefficients for the substrate and product as well as the lowest oxygen, substrate and product mass-transfer coefficients compared to the other ILs under the studied operating conditions. These results indicate that the effect of the IL on the cell viability is an essential parameter that must be considered before the application of an IL in TPPB technology.

The oxidative dehydrogenation of ethane (ODH-Et) seems the most promising alternative to produce ethylene compared to conventional processes. Nevertheless, there is not even a pilot plant for ODH-Et worldwide nowadays. This work presents the simulation of the catalytic behavior of a highly active and selective MoVTeNbO catalyst for the ODH-Et in a wall-cooled industrial-scale packed-bed reactor with a tube to particle diameter ratio equal to 3.12. The feasibility of using this complex yet necessary reactor design, as well as the influence of operating conditions on conversion and yield along the reactor are analyzed. The simulations are carried out using a two-dimensional pseudo-heterogeneous model, which makes use of both a reliable kinetic model and reliable transport parameters. Specifically, the kinetic model, obtained from lab-scale experimental data, is coupled to the reactor model accounting for transport phenomena wherein the effect of hydrodynamics on heat transfer is assessed from independent experiments in absence of reaction in an industrial-scale reactor. The developed kinetics successfully accounts for both the inhibiting effect of adsorbed water on oxidative dehydrogenation and total oxidations and the effect of the inlet partial pressure of oxygen and ethane on conversion and selectivity. Besides, the reactor model elucidates the importance of accounting for the role of the hydrodynamics on the heat transport in order to have reliable conversion and yield predictions. From the parametric sensitivity study, the temperature of the coolant fluid and the inlet ethane concentration are variables for tuning the reactor performance.

This work studies the effect of intraparticle diffusion phenomena on the conceptual design of an industrial fixed-bed adsorber for the removal of Rhodamine B (RhB) basic dye by using an abundant low-cost natural zeolite. Initially, equilibrium and transient observations obtained from independent experiments at laboratory scale are fitted by means of Langmuir isotherm model and two kinetic models, i.e., intrinsic Langmuir model and apparent pseudo-second-order model, respectively. Furthermore, effective diffusion coefficient is estimated from independent experiments using particles of the natural zeolite that are supposed to be packed in the fixed-bed adsorber. Then, all this information is used to develop three pseudo-heterogeneous models with and without accounting explicitly for intraparticle diffusion to predict the performance of a fixed-bed adsorber: (i) Linear Driving Force model (LDF-M); (ii) Apparent Kinetic Approach model (AkA-M); and (iii) Kinetic-Diffusion model (kD-M). The three fixed-bed adsorber models lead to different tendencies related to their breakthrough curves and breakthrough points, indicating significant resistance to diffusional mass transfer. Even though three fixed-bed adsorber models accounts for adsorbent diffusion, kD-M approach is found to be a complex yet necessary approach to carry out the conceptual design of a fixed-bed adsorber packed with a natural zeolite since diffusion characteristic time and, hence, resistances to mass transport by diffusion are significant to be lumped in equilibrium or kinetic models via LDF-M or AkA-M, respectively.

The purpose of this study is to provide insights on the function of noble metals, namely Pt-Pd catalytic system, on the hydrodesulfurization (HDS) of alkyl-substituted dibenzothiophenes (a-DBTs) by means of kinetic modeling and contribution analyses. A series of Pt-Pd systems (1% wt nominal loading) supported on γ-Al2O3 (0-100, 20-80, 50-50, 80-20 y 100-0; %mol Pt - %mol Pd) are synthesized and evaluated during the HDS of 4,6-dimethyldibenzothiophene (4,6-DMDBT) at operating conditions relevant for industry: 320 oC, 500ppm of S and an H2 pressure of 5.5 MPa. A summary of their characterization is presented as reference to have a better understanding of the studied materials. Kinetic model based on a Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism and contribution analysis based on predicted reaction rates give rise to the following findings: the bimetallic catalyst 8Pt-2Pd/γ-Al2O3 (80-20; %mol Pt-%mol Pd) leads to the highest activity; in all Pt-Pd/γ-Al2O3 systems, Pt favors desulfurization reactions, i.e., 4,6-DMDBT to 3,3’-dimethylphenyl (3,3’-DMBP) and 4,6-dimethyltetrahydrodibenzothiophene (4,6-DM-th-DBT) to MCHT, whereas Pd favors hydrogenation of 4,6-DMDBT to 4,6-DM-th-DBT; and 4,6-DMDBT and methylcyclohexyltoluene (MCHT) are the hydrocarbons with the lowest and highest affinity to be adsorbed on the active sites from the studied Pt-Pd/γ-Al2O3 systems, respectively. ispartof: Fuel Processing Technology vol:132 pages:164-172 status: published

Salt effect on vapour–liquid equilibrium (VLE) has been a subject of intense investigation from experimental and modelling perspectives since the salting-in and salting-out effects might eliminate the possibility of azeotrope formation at saturation. Nevertheless, thermodynamic consistency evaluation of data generated from this type of studies, accounting for non-idealities of one or two of the phases involved, is mandatory. In this communication, a primary evaluation of thermodynamic consistency under a non-ideal VLE situation of data generated for an ethanol–water system with and without the addition of inorganic potassium chloride (KCl) salt is presented. The equilibrium data (T-x-y diagram) for ethanol–water system is generated under isobaric conditions, with and without 2 and 4 g/L concentration levels of KCl. The isobaric VLE data of ethanol–water system saturated with KCl concentrations are correlated by means of a modified Raoult's law to predict the activity coefficient of the volatile co...

In this study we developed a pseudo heterogeneous mathematical model for the oxidation of bicyclic ketone bicyclo[3.2.0]hept-2-to-6-one to bicyclic lactone (1S,5R)-(-)-2-oxabiciclo[3.3.0]oct-6-en-3-ona using whole cells of E. coli strain TOP10 pQR239 in a three-phase partitioning bioreactor (TPPB). The pseudo heterogeneous TPPB model accounted for mass transfer mechanisms occurring in the air–water and water–ionic liquid phases along with bioconversion and loss of cell viability caused by ionic liquid – trioctylmethylammonium bis(trifluoromethylsulfonyl)imide ([OMA][BTA]). The development of the model was based on reactor engineering principles and, hence, experiments with and without bioconversion were carried out in order to characterize thermodynamic ( K ps and K pp ), transport ( k s , k p and A ) and kinetic ( k i and k i ′ ) parameters along with the loss of cell viability ( k in ) parameter for the mechanisms involved. The model described adequately the bioconversion of experimental data with two different ionic liquid fractions, namely 5% (v/v) and 12.5% (v/v). A parametric sensitivity analysis of the model was conducted to obtain information on the effect of oxygen transport rate on bioconversion. The development of the TPPB model led to the following findings: (i) 5% (v/v) ionic liquid fraction caused less cell deactivation; (ii) presence of ionic liquid decreased the oxygen transport rate; and (iii) a higher oxygen transport rate lead to a higher bioconversion but also cell inactivation.

The work presents a kinetic study of the simultaneous hydrodesulfurization of dibenzothiophene and hydrogenation of aromatics with different chemical structures. This kind of studies are seldom reported, since many authors deal almost exclusively with hydrodesulfurization. Furthermore, most of these authors employ power rate laws for kinetic modelling neglecting a rigorous analysis of the thermodynamic parameters of the reactions; namely, adsorption enthalpies and entropies.Considering this fact, we decided to base our kinetic modelling on a Langmuir-Hinshelwood-Hougen-Watson (LHHW) formalism testing the hypothesis of the existence of one or two different catalytic sites for hydrogenation and desulfurization. The consistency of the aforementioned thermodynamic parameters was assessed considering the criteria postulated by Boudart.Our results allowed concluding that a LHHW model considering two actives sites provides a statically satisfactory fitting of experimental data. In addition, it was possible to determine that inhibition effects of aromatics on hydrodesulfurization exist but depend to some extent on the molecular structure of the aromatic.On the other hand, this work also contributes by providing experimental values of adsorption constants of compounds reacting under hydrotreatment conditions which despite the significant advances in theoretical calculations are not yet available in open literature.

The photocatalysis, sonocatalysis and their combination operated sequentially have been studied to treat the decolorization and mineralization of a cationic dye, Rhodamine B, using heterogeneous TiO2 catalyst. Effects of various operating parameters such as catalyst loading, H2O2 addition, and pH on photocatalytic and sonocatalytic processes were investigated. For both photocatalysis and sonocatalysis optimum catalyst and hydrogen peroxide concentrations were observed, while the dye degradation rates were favored at acidic conditions. Photocatalysis resulted in higher color degradation efficiencies compared with sonocatalysis. Coupled photosonocatalytic process showed better efficiencies for color degradation than the achieved by individual photocatalysis and sonocatalysis operating separately, implying possible synergy; however, no synergetic effect was observed for dye mineralization. Apparently the sequential photosonocatalytic operation process was more effective in inducing color degradation than mineralization.

The oxidative dehydrogenation of ethane to ethylene (ODH-Et) is investigated over a high activity–selectivity MoVTeNb mixed oxide. Experiments are performed using a mixture of ethane, oxygen and nitrogen as feedstock, at temperatures from 400 to 480 °C, inlet partial pressures of oxygen and ethane from 5.0 to 24.2 kPa, and space–times from 10 to 140 g cat h mol ethane −1 . Ethylene selectivity varies from 76% to 96%, for an ethane conversion range 17–85%. In a set of experiments at 440 °C feeding ethylene instead of ethane, ethylene conversion is from 3% to 14% and CO x are the only reaction products, the CO being the dominant species with a selectivity range 73–79%. Kinetic models based on Langmuir–Hinshelwood–Hougen–Watson (LHHW) and Mars–van Krevelen (MvK) formalisms, and combinations of them are developed to describe the ODH-Et. Physicochemical and statistical criteria are employed to contrast the performance of these kinetic approaches. The LHHW kinetics exhibits the best capacity to represent the observations, being a potential model for the conceptual design of ODH-Et reactors in future investigations. Kinetic parameters indicate: (i) ethylene formation is the reaction demanding the lowest activation energy; (ii) total oxidations of ethane are the reactions demanding the largest activation energies; (iii) reaction rates, including that of catalyst oxidation, are weakly affected by changes in the oxygen partial pressure, explaining the high selectivity to ethylene of MoVTeNbO; and (iv) water is the component with the highest affinity to be adsorbed on active sites affecting negatively reaction rates.

An adequate description of the velocity field is of utmost importance in the rational design of wall-cooled packed bioreactors applied to solid-state fermentation. This contribution assessed the hydrodynamics under abiotic conditions in a novel bench-scale wall-cooled tray bioreactor packed with moistened particles of agroindustrial waste. The work, in particular, aimed at determining hydrodynamic descriptors under operating conditions of industrial interest: wall temperatures of 25–45 °C, controlled moisture content of 6–60% and specific volumetric flow rates of 1.25–62.50 Lair.kgs–1.min−1. A two-zone momentum model was developed, allowing the description of velocity profiles and the characterisation of viscous and inertial resistances due to the interaction between the solid and fluid in the core and wall regions of the packed tray. The core region used Blake-Kozeny and Burke-Plummer approaches, and the wall region used a pseudo-boundary layer approach to describe velocity profiles. The two-zone model was submitted to regression analyses, and hydrodynamic parameters were estimated, exhibiting statistical significance and phenomenological consistency. The two-zone model reduced computing time in describing the same velocity profiles by 3000–3600% compared to the conventional hydrodynamic model (Navier-Stokes-Darcy-Forchheimer equations); the results are thoroughly analysed and discussed. As observations of pressure drop were about two orders of magnitude higher than those predicted by classical correlations developed for chemical packed beds, a pseudo-heuristic correlation was developed; this permitted the determination of permeabilities affecting viscous and inertial frictional losses in the core region. The Darcy number (10−8

The aim of this present study was to investigate the degradation of Rhodamine B (RhB) in aqueous solution under the influence of ultrasound irradiation. An ultrasonic reactor was used to investigate the effect of different operational parameters such as dye initial concentration, ultrasound power, pH and electrical conductivity. The results showed an increase in decolourization rate with decreasing pH, but colour removal efficiency decreased with increasing initial dye concentration. It was found that an optimum electrical conductivity of the solution exists on enhancing the degree of RhB degradation. Sonolytic degradation data from the present and other works in the literature were analysed by Langmuir-type kinetics. The apparent reaction rate constant was strongly influenced by both irradiation power density and frequency, and based on the experimental data a mathematical correlation between them was obtained.

In the present work the agglomeration of a natural organic solid in a top-spray fluidized bed at bench scale was studied by means of statistical analysis and modeling using a discretized population balance. These engineering approaches were coupled to elucidate the influence of elutriated fines recirculation and its interaction with bed temperature and atomizing binder time on agglomeration mechanisms of solids presenting initial particle diameter polydispersity. First, a 23 factorial design was considered, accounting for the factors of atomizing binder time and bed temperature with and without consideration of the recirculation of elutriated fines into the fluidized chamber. Second, the agglomerate observations were analyzed by a variance analysis, with a significance level of 5%, using the mean particle diameter as response variable. Finally, the observations were predicted through a discretized population balance accounting for nucleation, agglomeration, and growth kinetics. The results indicated that ...

The biosorption properties of ethylenediaminetetraacetate (EDTA)-treated biomass of baker’s yeast (Saccharomyces cerevisiae) are studied for the removal of Cadmium(Cd), Lead(Pb), and Copper(Cu) from artificially prepared industrial wastewater. The metal ions are chosen for biosorption studies with regard to their availability in industry and potential pollution impact. The optimum biosorption capacity of these metal ions on the biomass is obtained at pH 5. It is observed that the sorption capacity of EDTA-treated biomass increases when the initial concentration of the metal ions is increased. Both Langmuir and Freundlich isotherm models are used to fit experimental biosorption equilibrium data. The maximum biosorption capacity as determined via the Langmuir isotherm is 32.26, 200.0, and 17.24 mg/g for Cd(II), Pb(II), and Cu(II) ions, respectively. The kinetics of biosorption is studied using both pseudo first order and pseudo second order models. Based on a linear regression correlation coefficie...

The kinetic effect of quinoline (Q) and its reaction by-products, i.e. 1,2,3,4-tetrahydroquinoline (1,4-THQ), decahydroquinoline (DHQ) and orthopropylaniline (OPA), on the hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT) was studied in the presence of a commercial NiMoP/Al 2 O 3 catalyst under operating conditions relevant to industrial applications. Kinetic observations and modelling based on a Langmuir–Hinshelwood–Hougen–Watson (LHHW) mechanism, accounting for most of the observed Q and 4,6-DMDBT by-products, indicated that Q, 1,4-THQ and DHQ are the main HDS reaction inhibitors, even at nitrogen concentrations as low as 25 ppm. To some extent Q and 1,4-THQ were adsorbed favorably on the HDS catalytic active sites, being more reactive than most of the sulfur and nitrogen-containing molecules. Besides, DHQ was less reactive than Q and 1,4-THQ, despite a significant adsorption affinity on the HDS catalytic active sites. As a consequence, Q and 1,4-THQ inhibited HDS reactions at lower Q conversions, whereas DHQ inhibited them at higher Q conversions.

Baeyer–Villiger bioconversion productivity of the cyclic ketone (±)-cis-bicyclo [3.2.0] hept-2-en-6-ona by the biocatalyst Escherichia coli TOP10 pQR239 in a multiphase system can be limited by mass transport. Mass transfer rates through the liquid–liquid interface depend on the volumetric mass transfer coefficient (kA) and the substrate and product partition coefficients. In situ experimental determination of the volumetric mass transfer coefficient in a partitioning bioreactor is complex. In this work, the substrate (kS) and product (kP) global mass transfer coefficients were determined in a modified Lewis cell in three water–ionic liquids systems. The ionic liquids used were butylmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide [MeBuPyrr][BTA], trioctylmethylammonium bis(trifluoromethylsulfonyl)imide [OMA][BTA] and 1-butyl-3-metyl-imidazolium hexafluorophosphate [BMIM][PF6]. The maximum kS and kP values obtained were 4.35 × 10−5 and 1.21 × 10−5 m s−1 for water-[MeBuPyrr][BTA] system; 1.53 × 10−5 and 7.84 × 10−6 m s−1 for water-[OMA][BTA] system, respectively; and kS values up to 1.01 × 10−5 m s−1 were found for the water-[BMIM][PF6] system. The association among the mass transfer coefficients and the physicochemical properties (interfacial tension, viscosity and density) and the thermodynamics (partition coefficients) are analysed and discussed. Finally, the volumetric mass transfer coefficients (kSA and kPA) were calculated using interfacial areas (A) of the dispersed ionic liquid phase estimated from the “Sauter” mean drop diameter (d32) in a one litre stirred tank partitioning bioreactor.

In this work, the role of hydrodynamics in an industrial-scale packed-bed catalytic reactor with a low tube/particle diameter ratio (dt/dp ∼ 3) and the role of redox dynamics of the catalyst surface together with the use of a catalyst activity profile are assessed on the heat transport during the partial oxidation of o-xylene on a V2O5/TiO2 catalyst. Temperature and concentration observations at different steady-state conditions are used to test the modeling approach, and reasonably good predictions are obtained when (1) the information contained in the heat-transport parameters, estimated from a boundary layer approximation to the hydrodynamics in the absence of chemical reactions [Ind. Eng. Chem. Res. 2007, 46 (23), 7426−7435], is used in the reactor model and (2) the redox catalyst dynamics, included in the reaction kinetics, is used, together with an empirical catalyst activity profile.