Two-phase Model of Markov Processes for Particle Transport in Fluidized Bed Reactors

2008 ◽  
Author(s):  
Hui Gao ◽  
Yan Fu ◽  
Jimin Yuan ◽  
Jianping Li
Keyword(s):  
Fluidized Bed ◽  
Markov Processes ◽  
Particle Transport ◽  
Phase Model ◽  
Fluidized Bed Reactors ◽  
Two Phase

scholarly journals Comparative simulation study of gas-phase propylene polymerization in fluidized bed reactors using aspen polymers and two phase models

2013 ◽  
Vol 19 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Ahmad Shamiria ◽  
M.A. Hussaina ◽  
Farouq Mjallic ◽  
Navid Mostoufid
Keyword(s):  
Molecular Weight ◽  
Gas Phase ◽  
Production Rate ◽  
Fluidized Bed ◽  
Average Molecular Weight ◽  
Phase Model ◽  
Propylene Polymerization ◽  
Flow Index ◽  
Fluidized Bed Reactors ◽  
Two Phase

A comparative study describing gas-phase propylene polymerization in fluidized-bed reactors using Ziegler-Natta catalyst is presented. The reactor behavior was explained using a two-phase model (which is based on principles of fluidization) as well as simulation using the Aspen Polymers process simulator. The two-phase reactor model accounts for the emulsion and bubble phases which contain different portions of catalysts with the polymerization occurring in both phases. Both models predict production rate, molecular weight, polydispersity index (PDI) and melt flow index (MFI) of the polymer. We used both models to investigate the effect of important polymerization parameters, namely catalyst feed rate and hydrogen concentration, on the product polypropylene properties, such as production rate, molecular weight, PDI and MFI. Both the two-phase model and Aspen Polymers simulator showed good agreement in terms of production rate. However, the models differed in their predictions for weight-average molecular weight, PDI and MFI. Based on these results, we propose incorporating the missing hydrodynamic effects into Aspen Polymers to provide a more realistic understanding of the phenomena encountered in fluidized bed reactors for polyolefin production.

Modified two-phase model with hybrid control for gas phase propylene copolymerization in fluidized bed reactors

2015 ◽  
Vol 264 ◽  
pp. 706-719 ◽  
Author(s):  
Ahmad Shamiri ◽  
Suk Wei Wong ◽  
Mohd Fauzi Zanil ◽  
Mohamed Azlan Hussain ◽  
Navid Mostoufi
Keyword(s):  
Gas Phase ◽  
Fluidized Bed ◽  
Hybrid Control ◽  
Phase Model ◽  
Fluidized Bed Reactors ◽  
Two Phase

scholarly journals Gas solid contacting measurements in a turbulent fluidized bed by oxidation of carbon monoxide

2019 ◽  
Vol 23 (Suppl. 5) ◽  
pp. 1413-1423
Author(s):  
Robbie Venderbosch ◽  
Wolter Prins ◽  
Swaaij van
Keyword(s):  
Mass Transfer ◽  
Fluidized Bed ◽  
Phase Model ◽  
Internal Diameter ◽  
Turbulent Regime ◽  
Dense Phase ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Fluid Bed ◽  
Real Flow

The conversion rate of the mass transfer controlled oxidation of CO over a Pt/?-alumina catalyst (d = 65 ?m) has been studied in a fluidized bed (internal diameter = 0.05 m) p operated close to and in the turbulent fluid bed regime. The objectives were to investigate the gas-solids contacting efficiency to evaluate the conversion data in terms of overall mass transfer coefficients and define the apparent contact efficiency. At high superficial gas velocities, the concept of formation of particle agglomerates and voids is more realistic than the two-phase model considering discrete bubbles and a dense phase. The two-phase model is not useless but has hardly any relation with the real flow pattern in the turbulent regime.

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