02198nas a2200229   4500008004100000022001400041245010100055210006900156260010600225300001200331490000700343520133500350653000801685653001901693653001801712653001901730653002601749653001501775100002401790700002201814856013201836       2007                        eng d  a0009-250900aSinglejet fluidized beds: experiments and CFD simulations with glass and polypropylene particles0 aSinglejet fluidized beds experiments and CFD simulations with gl  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJAN  a167-1830 v623 a<p>Understanding hydrodynamics of bubbling fluidized beds is crucial in proper design and scale up of these beds. CFD models have shown promise in gaining this understanding. In order to generate confidence in CFD models, predicted time averaged and dynamical characteristics of the bubbling fluidized beds need to be validated against experimental data. This paper describes such studies with rectangular fluidized beds operated with a central jet. Digital image analysis and analysis of wall pressure fluctuations were used for this characterization. Fluidization of two types of particles, glass and polypropylene (PP) was studied at two different initial bed heights of H/D = 1 and 2 with three central jet velocities 5, 10 and 20 m/s. Time averaged as well as dynamical characteristics were studied. The Eulerian-Eulerian two fluid model based on kinetic theory of granular flows was used to simulate these experiments. The predicted results were compared with the experimental data and previously published correlations. Although, there is agreement with experimental data in some aspects, complete agreement was not found. The presented experimental data and comparison with CFD predictions will provide useful basis for further work on understanding bubbling fluidized beds. (c) 2006 Elsevier Ltd. All rights reserved.</p>10aCFD10afluidized beds10ahydrodynamics10aimage analysis10apressure fluctuations10asingle jet1 aUtikar, Ranjeet, P.1 aRanade, Vivek, V.  uhttps://library.ncl.res.in/content/singlejet-fluidized-beds-experiments-and-cfd-simulations-glass-and-polypropylene-particles-002019nas a2200217   4500008004100000022001400041245009200055210006900147260006800216300001400284490000800298520122500306653001301531653001601544653003301560100002401593700002301617700001801640700002201658856012101680       2008                        eng d  a0021-899500aModeling of a fluidized bed propylene polymerization reactor operated in condensed mode0 aModeling of a fluidized bed propylene polymerization reactor ope  a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcMAY  a2067-20760 v1083 a<p>The gas-phase polymerization of propylene is one of the most widely accepted and commercially used processes for the manufacture of polypropylene (PP). Because of the highly exothermic nature of polymerization reactions, temperature runaway and subsequent polymer melting and agglomeration may occur, and the reactor has to be operated in a small operating window for safety. The addition of liquid monomer for heat removal (condensed mode) broadens the operating window and can substantially increase (by 50-100%) the capacity of given reactor hardware. This article describes the extension of a comprehensive mathematical model for the simulation of fluidized bed PP reactors to include the condensed mode of operations. The model is used to determine the influence of the operating parameters on the polymer properties and particle size distribution. The model is also used to determine the effects of two active sites and the reaction kinetics on macroscopic variables. The developed framework is useful for simulating multimonomer, multisite Ziegler-Natta-type olefin fluidized bed polymerization reactors operated under condensed mode. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 108: 2067-2076, 2008.</p>10aModeling10aPolyolefins10aZiegler-Natta polymerization1 aUtikar, Ranjeet, P.1 aHarshe, Yogesh, M.1 aMehra, Anurag1 aRanade, Vivek, V.  uhttps://library.ncl.res.in/content/modeling-fluidized-bed-propylene-polymerization-reactor-operated-condensed-mode-0