Numerical Simulation To Evaluate The Effect From Pre-polymerization On The Behavior Of Tubular Reactors [simulação Numérica Aplicada Para Avaliar O Efeito Da Pré-polimerização No Comportamento De Reatores Tubulares]

The present study uses a phenomenological model to simulate a continuous, two-stage polymerization process. This system is composed by a continuous stirred tank reactor (CSTR) for monomer pre-polymerization (first stage), connected to a tubular reactor (second stage) to carry out the reaction up to high conversion values. A comprehensive non-iso-thermal 2-D model (axial and radial variations) was used to predict the tubular reactor behavior. A polymer characterization model was also developed to provide estimates of the polymer average molecular weight and polydispersity. According to the results, polymerization reactions carried out in a continuous two-stage system provide a polymer with less heterogeneous properties than the one obtained in a single tubular reactor. Besides, it is possible to produce a more homogeneous polymer increasing the viscosity of the mixture fed in the tubular reactor.173250257McGreavy, C., (1994) Polymer Reactor Engineering, , 1st ed, VCH Publishers, New YorkCabral, P. A.Melo, P. A.Biscaia Jr., E. C.Lima, E. L. & Pinto, J. C. - Polym. Eng. Sci., 43, 6, p.1163 (2003);Tien, N.-K.Flaschel, E. & Renken, A. - Polymer Reaction Engineering - Influence of Reaction Engineering on Polymer Properties, Hanser Publishers (1983);Chen, C.C., (1994) Polym. Plast. Technol. Eng, 33 (1), p. 55Lynn, S., Huff, J.E., (1971) AIChe J, 17 (2), p. 475Husain, A., Hamielec, A.E., (1976) AIChe Symp. Series, 72 (160), p. 112Nogueira, A.L., Lona, L.M.F., Machado, R.A.F., (2004) J. Appl. Pol. Sci, 91, p. 871Soroush, M., Kravaris, C., (1993) AIChe J, 39, p. 1920Marten, F.L., Hamielec, A.E., (1982) J. Appl. Pol. Sci, 27, p. 489Stevens, C.J., Mathematical Modeling of Bulk and Solution Free Radical Polymerization in Tubular Reactors (1988), Ph.D. Thesis, University of Winscosin, Madison, EUAHui, A., Hamielec, A.E., (1968) J. Pol. Sci, 25, p. 167Hamer, J.W., Ray, W.H., (1986) Chem. Eng. Sci, 41 (12), p. 3083Holman, J.P., (1963) Heat Transfer, , Mc Graw Hill, New YorkChen, C.C., Nauman, E.B., (1989) Chem. Eng. Sci, 44 (1), p. 179Cutter, L. A. & Drexler, T. D. - Comp. Appl. Pol. Sci., p.13 (1982);Hui, A., Hamielec, A.E., (1972) J. Appl. Pol. Sci, 16, p. 749Husain, A., Hamielec, A.E., (1978) J. Appl. Pol. Sci, 22, p. 1207Kricheldorf, H.R., (1992) Handbook of Polymer Synthesis, , Marcel Dekker, New YorkMcLaughlin, H. S.Mallikarjun, R. & Nauman, E. B. - AIChe J., 32, 3, p.419 (1986);Wyman, C.E., Carter, L.F., (1976) AIChe Symp. Ser, 72 (160), p. 1Powell, F.E., Brooks, B.W., (1995) Chem. Eng. Sci, 50 (5), p. 837Soliman, M. A.Aljarboa, T. & Alahmad, M. - Polym. Eng. Sci., 34, p.1464 (1994);Tossun, G., (1992) AIChe J, 38, p. 42

Synthesis and application on metal substrates of ML33 functionalized with silver nanoparticles to evaluate antibacterial activity

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Glycerol desorption from ion exchange and adsorbent resin using supercritical fluid technology: An optimization study

In this study, glycerol desorption from Purolite® PD206 resin was investigated using conventional and supercritical fluids (SCF) techniques. Untreated biodiesel was purified by dry washing using the resin and, after purification, the glycerol desorption was carried out using absolute ethanol under atmospheric conditions at different mass flows (10–30 g/min) or using ethanol-modified supercritical CO2 (1:3 molar ratio of ethanol:CO2), under a pressure of 140 bar, within a temperature range of 106–134ºC and with mass flow rates of 6–34 g/min. The results showed that ethanol is an efficient solvent for this process and that the supercritical desorption is much faster than conventional desorption process. Employing the Response Surface Methodology (RSM) it was found that temperature has the greatest effect on the resin regeneration time using supercritical fluids. Optimum conditions obtained were 106.1ºC and 21.9 g/min, in which the resin was regenerated in only 4.17 min.Peer ReviewedPostprint (published version