1,721,057 research outputs found
Evaluation of hydrogen transfer in FCC catalysts. A new approach for cyclohexene as a test reactant
Get PDFThe conversion of cyclohexene over different commercial FCC catalysts in a batch fluidized-bed reactor under very short contact times at 300°C, was described by means of a simple lumped kinetic model that accounted for the observed yield patterns. The main branch of reaction starting from the adsorption of cyclohexene was used to assess an index based on kinetic parameters that defines the relative significance of hydrogen transfer reactions in a set that also includes proton transfer and cracking reactions. Complementary experiments with pulses of reactant on a fixed-bed reactor allowed to establish the best temperature to obtain maximum sensitivity to hydrogen transfer. The same evolutions were observed for the relationships between the index of hydrogen transfer and the paired acid site density with the Y zeolite unit cell size, confirming that two regions can be defined separated by unit cell sizes of about 24.28–24.30 Å, the correlations being stronger at low values of this parameter.Fil: de la Puente, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Sedran, Ulises Anselmo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentin
Conversion of pine sawdust bio-oil (raw and thermally processed) over equilibrium FCC catalysts
Get PDFA raw bio-oil from pine sawdust, the liquid product from its thermal conditioning and a synthetic bio-oil composed by eight model compounds representing the main chemical groups in bio-oils, were converted thermally and over a commercial equilibrium FCC catalyst. The experiments were performed in a fixed bed reactor at 500 C. The highest hydrocarbon yield (53.5 wt.%) was obtained with the conditioned liquid. The coke yields were significant in all the cases, from 9 to 14 wt.%. The synthetic bio-oil produced lesser hydrocarbons and more oxygenated compounds and coke than the authentic feedstocks from biomass. The previous thermal treatment of the raw bio-oil had the positive effects of increasing 25% the yield of hydrocarbons, decreasing 55% the yield of oxygenated compounds and decreasing 20% the yield of coke, particularly the more condensed coke.Fil: Bertero, Melisa Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones En Catalisis y Petroquímica "ing. Jose Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones En Catalisis y Petroquímica "ing. Jose Miguel Parera"; ArgentinaFil: Sedran, Ulises Anselmo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones En Catalisis y Petroquímica "ing. Jose Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones En Catalisis y Petroquímica "ing. Jose Miguel Parera"; Argentin
Separation of ternary hydrocarbon mixtures on Y zeolite membranes
No full textThe permeation of a mixture of n-hexane, n-decane and toluene through a 40 μm Y zeolite tubular membrane on a support with negligible resistance to the mass transfer at 250 °C was modelled based on the Maxwell-Stefan formulation and the ideal adsorbed solution theory (IAST). Individual adsorption parameters were obtained with a batch fluidized bed reactor and diffusion parameters were taken from the literature. The model allowed to predict the transient fluxes and surface coverages through the membrane, showing that the responses of the components diffusing faster (n-hexane and n-decane) overshoot their steady-state values. The permeance predictions (10-8 mol/s m2 Pa) ranged from 1.2 to 20 for n-decane, from 0.4 to 4.2 for n-hexane and from 0.8 to 4.0 for toluene, according to the feed pressure and composition. The permeance selectivities, defined with n-hexane as the reference, ranged between 3 and 6 for n-decane, and between 1 and 1.8 for toluene. It was also possible to define the association between hydrocarbon coverage profiles in the membrane and the corresponding resulting fluxes.Fil: Avila, Adolfo María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Sedran, Ulises Anselmo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentin
Immediate catalytic upgrading of soybean shell bio-oil
Get PDFThe pyrolysis of soybean shell and the immediate catalytic upgrading of the bio-oil over an equilibrium FCC catalyst was studied in order to define its potential as a source for fuels and chemicals. The experiments of pyrolysis and immediate catalytic upgrading were performed at 550 C during 7 min with different catalysts to oil relationships in an integrated fixed bed pyrolysis-conversion reactor. The results were compared under the same conditions against those from pine sawdust, which is a biomass source commonly used for the production of bio-oil. In the pyrolysis the pine sawdust produced more liquids (61.4%wt.) than the soybean shell (54.7%wt.). When the catalyst was presented, the yield of hydrocarbons increased, particularly in the case of soybean shell, which was four time higher than in the pyrolysis. The bio-oil from soybean shell produced less coke (between 3.1 and 4.3%wt.) in its immediate catalytic upgrading than that from pine sawdust (between 5 and 5.8%wt.), due to its lower content of phenolic and other high molecular weight compounds (three and five times less, respectively). Moreover, soybean shell showed a higher selectivity to hydrocarbons in the gasoline range, with more olefins and less aromaticthan pine sawdust.Fil: Bertero, Melisa Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Sedran, Ulises Anselmo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentin
Coprocesamiento de bio-oils en refinerías. Caracterización y pretratamiento térmico
Get PDFSe estudió la pirólisi de distintas biomasas (aserrín de pino, aserrín de algarrobo y cáscara de trigo) en medio inerte (N2). Los bio-oils se generaron en un reactor de lecho fijo a 550 ºC y con una rampa de 15 ºC/min. La producción más elevada de bio-oil se obtuvo para el aserrín de pino (39 %p). Los bio-oils obtenidos se analizaron por GC/MS luego de someterse a fraccionamiento con agua y éter. Las fracciones contenían principalmente aldehídos, cetonas y fenoles. Se estudió el efecto de un tratamiento térmico sobre la composición de los bio-oils, a fin de evaluar los cambios que podrían ayudar a co-procesarlos en refinerías convencionales, dado su alto potencial de formación de coque. El tratamiento térmico se realizó utilizando una rampa de 12 ºC/min y temperatura final de 500 ºC. Este tratamiento produjo una fuerte disminución en el CCR, del orden de 70 % , y un leve aumento en el contenido de agua.Fil: Bertero, Melisa Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: de la Puente, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Sedran, Ulises Anselmo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentin
Use of stirred batch reactors for the assessment of adsorption constants in porous solid catalysts with simultaneous diffusion and reaction. Theoretical analysis
Get PDFA simple, pseudo-equilibrium model was derived for a catalytic system with a first order chemical reaction and simultaneous diffusive and adsorptive processes, in order to assess the corresponding kinetics and Henry law's-type adsorption parameters. Solutions from this model were compared to exact solutions from a more detailed, general model. It was shown that under most of the experimental conditions used in stirred batch reactors and the usual model considerations, it is only possible to assess apparent adsorption parameters. Also, we observed that a stable relationship between the concentrations in the gas and solid phases is reached. The error produced in assuming that the apparent adsorption constant is the real one was calculated to be very important. The value of the apparent adsorption constant depends on various system properties and experimental conditions, such as the Thiele modulus, the amount of catalyst and the contact time. The ratio between the apparent and real adsorption constants was shown to be the transient effectiveness factor at any moment. This ratio reaches a maximum value for the pseudo-equilibrium state, that is always larger than the steady-state effectiveness factor, becoming closer as long as the system's adsorption capacity decreases. The analysis determines the operative conditions to reduce the parametric correlation. Also a criterion for the applicability of usual approximations in the assessment of kinetics and equilibrium adsorption parameters in porous solid catalysts by means of pulse injection methods is established.Fil: Bidabehere, Claudia María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Sedran, Ulises Anselmo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentin
Recycling of waste plastics into fuels. LDPE conversion in FCC
No full textIn order to study the tertiary recycling of waste polymers in standard FCC units low density polyethylene (LDPE) was dissolved into a commercial vacuum gas oil at 2 and 6 wt.% and converted over two equilibrium FCC catalysts of the octane-barrel and resid types in a CREC Riser Simulator laboratory reactor. The reaction temperatures were 500, 525 and 550 ◦C, the mass catalyst to oil relationship was 6.35 and the contact times were from 3 to 30 s. The study included the effect of the concentration of LDPE over conversion, the various product (dry gas, LPG, gasoline, LCO and coke) yields and selectivities. Results were very similar for the two concentrations. At typical conversions of 70 wt.%, dry gas and gasoline yields increased about 10 wt.%, LPG yields between 9 and 13 wt.%, LCO yields decreased more than 15 wt.% andcoke yields were lower than 7.7 wt.% The RON index of gasoline was improved slightly (up to one point), mainly due to significant increases in olefin concentrations, while the fuel quality of the LCO cut was not affected. LDPE is easily converted and seems to be subjected to primary reactions of catalytic cracking, thus increasing the yields of olefins in the LPG and gasoline boiling ranges. It was concluded that recycling waste LDPE by co-processing it as part of conventional feeds to the FCC would not interfere with the standard operation.Fil: Passamonti, Francisco Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Sedran, Ulises Anselmo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentin
Upgrading of bio-oils over equilibrium FCC catalysts. Contributions from alcohols, phenols and aromatics ethers
No full textThe conversions of oxygenated compounds of bio-oils (alcohols, phenols and aromatic ethers) on a equi-librium FCC catalyst were studied at 500◦C during 60 s in a fixed bed laboratory reactor. Methanol,phenol and 2,6-dimethoxyphenol were dissolved in water and 1,2,4-trimethoxybenzene in benzene at5 %wt. Identical experiments were performed over inert SiC. Conversions were very different, the highestone being that of 1,2,4-trimethoxybenzene (95.7 %wt.), followed by 2,6-dimethoxyphenol (75.0 %wt.),methanol (60.8 %wt.) and phenol (54.9 %wt.). Deoxygenation in all the reactants was from dehydrationand decarboxylation. The highest yield of hydrocarbons (47.1 %wt.) and coke (16.0 %wt.) were from 1,2,4-trimethoxybenzene, which, together with methanol, yielded mainly aromatics in the gasoline range. Onthe contrary, phenol and syringol yielded C4-hydrocarbons with high content of olefins. The highestamounts of oxygenated compounds were produced by 2,6-dimethoxyphenol. The thermal conversionswere similar to the catalytic ones in the only case of 1,2,4-trimethoxybenzene, but much lower with theother reactants. In comparison to the catalytic experiments, thermal tests yielded much more hydrocar-bons with 1,2,4-trimethoxybenzene, and oxygenated compounds with 2,6-dimethoxyphenol, than theother reactants. These tests could help in the prediction of specific contributions by these reactants ifbio-oils are co-processed in FCC units or upgraded over acidic catalysts.Fil: Bertero, Melisa Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Sedran, Ulises Anselmo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentin
Formation of gum precursors in FCC napthas
Get PDFThe trends to the formation of gum precursors in gasoline were studied through the yields and selectivities of C5 olefins in the conversion of both a VGO and nC16 over two equilibrium commercial FCC catalysts. The experiments were performed at 500 and 550 °C, catalyst-to-oil ratio of 6.1 and short contact times of up to 12 s in a Riser Simulator laboratory reactor. The behaviors of C5 olefins observed in the conversion of both reactants were similar: the yield of olefins (linear, branched, and cyclic) and dienes increased as a function of contact time and temperature, the amounts being different according to the characteristics of the catalysts. Gasoline composition was very sensitive to the formulation of the catalysts and their resulting hydrogen transfer capabilities. In the conversion of gas oil, maximum selectivities of about 59, 21, 31, and 3.3% were observed for total, linear, iso-, and cyclic olefins in the C5 group, respectively, and the maximum selectivity of dienes in the group was 3.9%. For the same hydrocarbons, the conversion of nC16 showed higher yields at the same conditions. It was verified that the reaction temperature is especially important to control the yield of diene compounds. A simple test methodology to predict the stability of FCC naphthas could be based on a reduced set of experiments with equilibrium catalysts, either with a commercial feedstock or test reactant nC16.Fil: de la Puente, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Sedran, Ulises Anselmo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentin
Operation of FCC with mixtures of regenerated and deactivated catalyst
Get PDFThe operation of FCC with mixtures of coked and regenerated catalyst was studied with a riser simulator reactor on two equilibrium catalysts at 550◦C. The coked catalysts maintain an activity level that enables them to be used in the mixtures. The catalytic performances of the regenerated catalysts were used as references against which the behaviors of 25:75 and 50:50 (coked:regenerated) mixtures were compared. It was observed that overall catoil has to be increased to maintain conversion. While the yields of gases, gasoline and LCO showed to be independent of the operative mode, changes were observed in the selectivity to light olefinsC4?C6that are mainly due to changes in the yields of the isoparaffins in the groups. In turn, these changes could be the consequence of the resulting density of paired acid sites in the zeolite components on hydrogen transfer reactions, due to the contributions by the coked and regenerated portions of catalysts. Coke yields in mixtures of coked and regenerated catalysts are not higher, which would allow increasing catalyst circulation without impacting on heat balance. The particularities of this new operation of FCC are very dependent on catalyst properties.Fil: Spretz, R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Sedran, Ulises Anselmo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentin
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