Programa de Pós-Graduação em Engenharia Química - PPGEQ/UNICAMP
URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/9656
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Tese Acesso aberto (Open Access) Análise de um processo de recobrimento de comprimidos em um sistema vibro-jorrado bidimensional(Universidade Estadual de Campinas, 1997) SOUZA, Célio Augusto Gomes de; KIECKBUSCH, Theo Guenter; http://lattes.cnpq.br/8568010039715375An experimental set up for the study of tablets coating in a two-dimensional spouted bed that uses vibration of the perforated base to enhance the circulation of the particles was developed. An acrylic rectangular upper section (4x32 cm) with fixed 4x4 cm draft plates was adjusted over 3 different convergent sections (inclination 50') with 4x4 cm, 4x6 cm or 4x8 cm bases and contained 800g, 1100g or 1300g of tablets, Air (0,8 to 1,6 m3/min) forced by a 7,5 cv blower, was cooled down to 55°C and spouted this bed. The lenticular tablets (0,12g; 0,25g., 0,44g) were coated with a polymeric aqueous solution (11% solids). A two-fluid atomizer (air pressure 82,7 1kPa) was used, inserted laterally, near the bed base, and showed no influence on the movement of the particles. The experimental characterization of the tablets circulation rates was emphasized, using a magnet (0,4062 g) that followed the particles, activating a bobbin located at the upper end of the draft plates. The electric pulses were processed by a data acquisition sistem and the cicle time distribution curves were adjusted by the Modified Spline fit technique. The mean of the cicle time distribution creased with are increase of the bed load and the size of the tablets in all comparative tests. The vibration (10 Hz, 8 mm amplitude) reduced the mean of the cicle time distribution by more than 10%, and also decreased its variance. The vibration also affected the maximum pressure drop (40% reduction) and the minimum spouting velocity. The vibro spouted bed showed higher- adhesion efficency (73 to 88%) than the non-vibrated spouted bed (66 to 79%) in all equivalent situations and the complete coating of the smaller tablets demanded less processing time due to higher surface area circulation rate.Dissertação Acesso aberto (Open Access) Transferência de calor com mudança de fase em processos de borbulhamento(Universidade Estadual de Campinas, 1986-04-25) SOUZA, Célio Augusto Gomes de; ANDRADE, Alberto Luiz de; http://lattes.cnpq.br/5905831095854831Heat transfer fenomena with phase change is analyed in a bubbling process, where heated gas hubbies pass through a liquid. The experimental evaporation rate is measured with an equipment which operates with gas feed temperatures in the range of 70 to 285°C, A diffusive transient model is presented in which the simultaneous transfer effects and surface bubble superheating are taken into account to calculate heat and mass transfer coefficients and flow rates. The modeling equations are presented in the explicit form thus permitting the direct calculations of heat and mass transfer rates during the evaporation of a liquid and the testing the predicted values with experimental results. A comparison between the simultaneous and the superheating models showed that at higher gas temperatures and higher residence times , both modeIs reproduce satisfactorily the operational conditions. in order to verify the equipment performance to obtain the bubbling time needed for the attainment of steady state, the liquid equilibrium temperature was theoretically calculated taking into a account the simultaneous and the superheating effects, being these results compared with the experimental values.