A two phase model of high temperature steam-only gasification of biomass char in bubbling fluidized bed reactors using nuclear heat

2011 ◽  
Vol 36 (1) ◽  
pp. 374-381 ◽  
Author(s):  
E.D. Gordillo ◽  
A. Belghit
Keyword(s):  
High Temperature ◽  
Fluidized Bed ◽  
Phase Model ◽  
Fluidized Bed Reactors ◽  
Two Phase ◽  
Nuclear Heat ◽  
Bubbling Fluidized Bed ◽  
Biomass Char ◽  
High Temperature Steam

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

CFD-DEM Modeling of CO2 Capture using Alkali Metal-Based Sorbents in a Bubbling Fluidized Bed

2014 ◽  
Vol 12 (1) ◽  
pp. 441-449 ◽  
Author(s):  
Zhonglin Zhang ◽  
Daoyin Liu ◽  
Yaming Zhuang ◽  
Qingmin Meng ◽  
Xiaoping Chen
Keyword(s):  
Fluidized Bed ◽  
Gas Flow ◽  
Fluidized Bed Reactors ◽  
Solid Sorbents ◽  
Bubbling Fluidized Bed ◽  
Shrinking Core ◽  
Simulation And Experiment ◽  
Kinetics Simulation ◽  
Reaction Processes ◽  
Back Mixing

Abstract This paper describes a CFD-DEM modeling of CO2 capture using K2CO3 solid sorbents in a bubbling fluidized bed, which takes into heat transfer, hydrodynamics, and chemical reactions. Shrinking core model is applied in reaction kinetics. Simulation and experiment results of bed pressure drop and CO2 concentration in the reactor exit agree well. Instantaneous dynamics as well as time-averaged profiles indicate detailed characteristics of gas flow, particle motion, and chemical reaction processes. The simulation results show an obvious core-annular flow and strong back-mixing flow pattern. CO2 concentration decreases gradually along the bed height, while regards on the lateral distribution CO2 concentration near the wall is lower than that in the middle zone where gas passes through faster. The effect of bubbles on CO2 reaction is two-sided: it can promote mixing which strengthens reaction, while it can be a short pass of gas which is not beneficial to reaction. The simulation is helpful for further understanding and optimal design of fluidized bed reactors of CO2 capture.

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