Hydrocracking of Fischer-Tropsch Products. Optimization of Diesel and Naphtha Cuts

Hydrocracking of Fischer-Tropsch synthesis products consisting of a mixture of C4–C30 paraffins and olefins over a platinum/amorphous silica–alumina catalyst was analyzed and optimized. A mathematical model of a batch reactor used for hydrocarbon hydrocracking was developed and the process was studied from a modeling point of view based on the kinetics of a bifunctional catalyst. The influence of temperature on the product yield distribution was evaluated. Time and temperature optimization were performed to obtain the best operating conditions to increase the fractions of naphtha and diesel that can be produced by Fischer-Tropsch synthesis

Production of fructo-oligosaccharides by Aspergillus ibericus and their chemical characterization

A great demand for prebiotics is driving the search for new sources of fructo-oligosaccharides (FOS) producers and for FOS with differentiated functionalities. In the present work, FOS production by a new isolated strain of Aspergillus ibericus was evaluated. The temperature of fermentation and initial pH were optimized in shaken flask to yield a maximal FOS production, through a central composite experimental design. FOS were produced in a one-step bioprocess using the whole cells of the microorganism. The model (R2 = 0.918) predicted a yield of 0.56, experimentally 0.53 ± 0.03 gFOS.ginitial sucrose1 was obtained (37.0 °C and a pH of 6.2). A yield of 0.64 ± 0.02 gFOS.ginitial sucrose1 was obtained in the bioreactor, at 38 h, with a content of 118 ± 4 g.L1 in FOS and a purity of 56 ± 3%. The chemical structure of the FOS produced by A. ibericus was determined by HPLC and NMR. FOS were identified as 1-kestose, nystose, and 1F-fructofuranosylnystose. In conclusion, A. ibericus was found to be a good alternative FOS producer.Clarisse Nobre acknowledges the Portuguese Foundation forScience and Technology (FCT) for her Post-Doc Grant [ref. SFRH/BPD/87498/ 2012] and the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124FEDER-027462), the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684), BioTecNorte operation(NORTE-01-0145-FEDER-000004) and the project MultiBiorefinery (POCI-01-0145-FEDER-016403) funded by European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

The fluidized bed reactor with a prepolymerization system and its influence on polymer physicochemical characteristics

This work addresses the influence of a prepolymerization system on the behavior of the fluidized bed reactor used for polyethylene production. Its influence on the polymer's physicochemical characteristics and production was also studied. The results indicate that the use of prepolymerized catalyst particles results in milder temperatures in the fluidized bed reactor, thus avoiding the formation of hot spots, melting of the polymer particle and reactor shutdown. Productivity can be enhanced depending on the operational conditions used in the prepolymerization reactor

The fluidized bed reactor with a prepolymerization system and its influence on polymer physicochemical characteristics

This work addresses the influence of a prepolymerization system on the behavior of the fluidized bed reactor used for polyethylene production. Its influence on the polymer's physicochemical characteristics and production was also studied. The results indicate that the use of prepolymerized catalyst particles results in milder temperatures in the fluidized bed reactor, thus avoiding the formation of hot spots, melting of the polymer particle and reactor shutdown. Productivity can be enhanced depending on the operational conditions used in the prepolymerization reactor.171179Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Fluidized-bed Reactor And Physicalchemical Properties Modeling For Polyethylene Production

A new steady-state model incorporating interactions between separate bubble and emulsion phases inside the reactor bed and a polymer physical-chemical characterization model were developed. A computer program, FBPOL, was also developed to accomplish the linkage of these two models, in order to predict the polymer grade that can be produced by different operational conditions. © 1999 Elsevier Science Ltd.23SUPPL. 1S803S806Choi, K.Y., Ray, W.H., The Dynamic Behaviour of Fluidized Bed Reactors for Solid Catalyzed Gas Phase Olefin Polymerization (1985) Chem.Eng.Sci., 40, pp. 2261-2279deCarvalho, A.B., Gloor, P.E., Hamielec, A.E., A Kinetic Mathematical Model for Heterogeneous Ziegler-Natta Copolymerization (1989) Polymer, 30, p. 280Kissin, Y.V., (1987) Isospecijic Polymerization of Olefins with Heterogeneous Ziegler-Natta Catalysts, , SpringerVerlag, New YorkMcAuley, K.B., MacGregor, I.F., Hamielec, A.E., A Kinetic Model for Industrial Gas-Phase Ethylene Copolymerization (1990) A. J. Ch. E. J., 36, pp. 837-850McAuley, K.B., Talbot, J.P., Harris, T.J., A Comparison of Two-Phase and Well-Mixed Models for Fluidized-Bed Polyethylene Reactors (1994) Chem. Eng. Sci., 49, pp. 2035-2045Zabisky, R.C.M., Chan, W.M., Gloor, P.E., Hamielec, A.E., A Kinetic Model for Olefin Polymerization in High-Pressure Tubular Reactors: a Review and Update (1992) Polymer, 33, pp. 2243-226