scholarly journals Heat transfer effect in scaling-up a fluidized bed reactor for propylene polymerization

RSC Advances ◽  
2018 ◽  
Vol 8 (50) ◽  
pp. 28293-28312 ◽  
Author(s):  
Panut Bumphenkiattikul ◽  
Sunun Limtrakul ◽  
Terdthai Vatanatham ◽  
Parinya Khongprom ◽  
Palghat A. Ramachandran
Keyword(s):  
Fluidized Bed ◽  
Fluidized Bed Reactor ◽  
Scaling Up ◽  
Transfer Effect ◽  
Operating Conditions ◽  
Propylene Polymerization ◽  
Fluidized Bed Reactors ◽  
Cfd Models ◽  
Reactor Temperature ◽  
And Performance

The effects of operating conditions and scaling-up on reactor temperature control and performance in propylene polymerization fluidized bed reactors were studied by phenomenological and CFD models.

scholarly journals Modeling of metallocene catalyzed propylene polymerization in fluidized bed reactors

2019 ◽  
Vol 268 ◽  
pp. 02002
Author(s):  
Chew-Sang Law ◽  
Mohd Azlan Hussain
Keyword(s):  
Fluidized Bed ◽  
Mixed Model ◽  
Monomer Concentration ◽  
Fluidized Bed Reactor ◽  
Propylene Polymerization ◽  
Fluidized Bed Reactors ◽  
Multi Scale ◽  
Reactor Temperature ◽  
Mixed Reactor ◽  
Reactor Models

A study was performed to improve the model for metallocene catalyzed polyolefin polymerization in fluidized bed reactor by adapting multi-scale modeling approach. Monomer concentration and reactor temperature was predicted using kinetic model of polypropylene homopolymerization coupled with well mixed reactor models of fluidized bed reactor. Well mixed model typically used for Ziegler-Nata was selected as supported homogeneous metallocene exhibited heterogeneous property similar to ZN catalyst. Result of simulation showed that model was able to predict reaction temperature accurate with around 3% over-prediction of reactor temperature, which is more accurate than previous model. Model predicted decrease in final monomer concentration from 0.9929 mol/s to 0.986 mol/s when initial reactor was raised from 25C to 75C.

Understanding the Effect of the Transition Period during the Air Gasification of Dried Sewage Sludge in a Fluidized Bed Reactor

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
María Aznar ◽  
Ángel E. González ◽  
Joan J Manyà ◽  
José L. Sánchez ◽  
M Benita Murillo
Keyword(s):  
Steady State ◽  
Sewage Sludge ◽  
Fluidized Bed ◽  
Atmospheric Pressure ◽  
Transition Period ◽  
Fluidized Bed Reactor ◽  
Operating Conditions ◽  
Polycyclic Aromatic ◽  
Reactor Temperature ◽  
Composition Changes

Air gasification of dried sewage sludge (DSS) in a fluidized bed has been studied as an effective alternative for the management of this material in a usable way. Nevertheless, one of the major issues in this technology is to deal with the tar formed during the process. To minimize the tar production, it is very important to optimize the operating conditions. In a previous work (Manyà et al., Energy Fuels, Vol. 19, 629–636, 2005) some unexpected results, in which tar production increases with the equivalence ratio, have been obtained. As it has been mentioned in that work, tar production could present unexpected trends while the bed composition changes from sand to a mixture of char and sand. Ashes contained in char have catalytic active metals which could promote gasification reactions. As the char content in the bed increases, the catalytic activity in the reactor could increase too, until the steady state is achieved. The aim of this work is to characterize the non-stationary period and its influence on the overall results obtained from gasification tests. Experiments have been carried out in a laboratory-scale BFB reactor at atmospheric pressure and at a reactor temperature of 1123 K with an equivalent ratio of 30%. Results show that at the beginning of the experiments the tar production was higher, until the steady state is reached. The gasification study has been enhanced with an analysis of tar composition by means of GC/MS and GC/FID. An effect of the transition period has been observed in tar composition also. The nitrogen aromatics percent increased with time whereas the polycyclic aromatic hydrocarbon decreased.

Influence of Seeding Conditions on Initial Biofilm Development during the Startup of Anaerobic Fluidized Bed Reactors

1989 ◽  
Vol 21 (4-5) ◽  
pp. 157-165 ◽  
Author(s):  
F. Ehlinger ◽  
J. M. Audic ◽  
G. M. Faup
Keyword(s):  
Fluidized Bed ◽  
Future Development ◽  
Protein Concentration ◽  
Specific Activity ◽  
Fluidized Bed Reactor ◽  
Fluidized Bed Reactors ◽  
Support Material ◽  
Biofilm Development ◽  
Initial Biofilm

The characterization of the biofilm of an anaerobic fluidized-bed reactor was completed under standard conditions. The distribution of the fixed protein concentration depended on the level in the reactor. The protein concentration reached 1520 µg.g−1 of support at the top of the reactor and only 1200 µg.g−1 at the bottom after 504 hours of operation but the specific activity of the biofilm was 33×10−4 µM acetate.h−1.mg−1 proteins at the bottom and only 26×10−4 µM.h−1.mg−1 at the top. The efficiency of a fluidized bed reactor and the composition of the biofilm changed with an increase of the pH from 7 to 8.5 during the seeding of the support material. Future development of the biofilm and the specific activity of the support were affected.

Phosphate removal in real anaerobic supernatants: modelling and performance of a fluidized bed reactor

1998 ◽  
Vol 38 (1) ◽  
pp. 275-283 ◽  
Author(s):  
P. Battistoni ◽  
P. Pavan ◽  
F. Cecchi ◽  
J. Mata-Alvarez
Keyword(s):  
Fluidized Bed ◽  
Contact Time ◽  
Fluidized Bed Reactor ◽  
Phosphate Removal ◽  
Plant Design ◽  
Air Stripping ◽  
And Performance ◽  
Ph Range ◽  
Very High ◽  
A2o Process

Phosphate removal in anaerobic supernatant coming from a centrifugation sludge station of an A2O process is studied. A fluidized bed reactor is employed to crystallize phosphate as hydroxyapatite or struvite using only air stripping to reach the supersaturation pH. The classic composition of supernatant (alkalinity 3550 mgCaCO3/l, PO4 139 mg/l, Mg 24 mg/l) does not require any addition of chemicals for phosphate removal. Seventeen runs are performed in a bench scale FBR obtaining very high conversion and removal efficiency and phosphate loss in the effluent ≤3.5%. The use of Ca or Mg enriched supernatant has no meaningful influence on efficiency, but it determines the prevalent salt formed between MAP or HAP. Efficiency can be related to pH and sand contact time in a double saturational model. The half efficiency constants: 0.075 h for t and 7.75 pH, have an important role in the process knowledge and optimization of plant design. Exhaust sand analysis indicates the same composition at the top, bottom and mean of the sand bed (39% mol MAP and 61% mol HAP). This result together with the high half efficiency constant for contact time indicate that the phosphate growth on the bed is not competitive. Finally, the phosphate release from the plant is studied. Results show a weak release rate, equivalent to 2.8-10% d−1 phosphate as MAP, obtained at an operative pH range of 8.1-8.4.

scholarly journals Development and assessment of speed-up algorithms for the reactive CFD–DEM simulation of fluidized bed reactors

2020 ◽  
Vol 5 (2) ◽  
pp. 278-288 ◽  
Author(s):  
Riccardo Uglietti ◽  
Mauro Bracconi ◽  
Matteo Maestri
Keyword(s):  
Fluidized Bed ◽  
Selection Procedure ◽  
Operating Conditions ◽  
Fluidized Bed Reactors ◽  
Effective Algorithm ◽  
Dem Simulation ◽  
Dem Simulations ◽  
Speed Up

PA and ISAT algorithms are developed to speed-up the CFD–DEM simulations of fluidized reactors. Also, a selection procedure of the most effective algorithm according to the operating conditions is developed, enabling the simulation of lab reactors.

Improved single phase modeling of propylene polymerization in a fluidized bed reactor

2012 ◽  
Vol 36 ◽  
pp. 35-47 ◽  
Author(s):  
Ahmad Shamiri ◽  
Mohd Azlan Hussain ◽  
Farouq Sabri Mjalli ◽  
Navid Mostoufi
Keyword(s):  
Fluidized Bed ◽  
Single Phase ◽  
Fluidized Bed Reactor ◽  
Propylene Polymerization

Characterization of a limestone in a batch fluidized bed reactor for sulfur retention under oxy-fuel operating conditions

2011 ◽  
Vol 5 (5) ◽  
pp. 1190-1198 ◽  
Author(s):  
Luis F. de Diego ◽  
Margarita de las Obras-Loscertales ◽  
Francisco García-Labiano ◽  
Aránzazu Rufas ◽  
Alberto Abad ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Fluidized Bed Reactor ◽  
Operating Conditions
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