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Bandar-e Emam Khomeyni, Iran

Borhani T.N.G.,Imperial College London | Afkhamipour M.,National Iranian Gas Company | Azarpour A.,Petronas University of Technology | Akbari V.,Razi Petrochemical Company | And 2 more authors.
Journal of Industrial and Engineering Chemistry | Year: 2016

This study presents a rate-based model of an absorber packed column for simultaneous absorptions of acid gases into methyldiethanolamine (MDEA) aqueous solution. The model is in good agreement with experimental data. The parametric study showed that the concentration of acid gases in the sweet gas stream increases by decrease in the specific surface area of packing. The peak of selectivity factor decreases with the increase in the mole ratio of CO2/H2S in the gas feed along the packed column. The sensitivity analysis reveals that selecting the accurate correlations of the gas-side mass transfer coefficient and specific surface area is vital. © 2015 The Korean Society of Industrial and Engineering Chemistry.

Akbari V.,University of Technology Malaysia | Akbari V.,Razi Petrochemical Company | Borhani T.N.G.,University of Technology Malaysia | Shamiri A.,University of Malaya | And 5 more authors.
Chemical Engineering Research and Design | Year: 2015

In an industrial fluidized bed polymerization reactor, particle size distribution (PSD) plays a significant role in the reactor efficiency evaluation. The computational fluid dynamic (CFD) models coupled with population balance model (CFD-PBM) have been extensively employed to highlight its potential to analyze the industrial-scale gas phase polymerization reactor (FBRs) utilizing ANSYS Fluent software. The predicted results reveal an acceptable agreement with the observed industrial data in terms of pressure drop and bed height. Courant number independent study has been carried out to record the mesh and time step independent results for large scale FBRs. Furthermore, the minimum fluidization velocity (Umf) and size-dependent particle growth rate have been assessed to emphasize the impact of PSD along the reactor. The results show transient regime in the case of minimum fluidization velocity. The simulation results signify that in order to improve the polymerization yield, the amount of gas velocity can be increased without change in the fluidization regime, i.e. segregation. Hence, the 2D CFD-PBM/DQMOM coupled model can be used as a reliable tool for analyzing and improving the design and operation of the gas phase polymerization FBRs. © 2015 The Institution of Chemical Engineers.

Leo C.Y.,University of Malaya | Shamiri A.,University of Kuala Lumpur | Aroua M.K.,University of Malaya | Aghamohammadi N.,University of Malaya | And 4 more authors.
Journal of Molecular Liquids | Year: 2016

The density and viscosity of aqueous mixtures of glycerol and N-Methyldiethanolamine (MDEA), glycerol and Monoethanolamine (MEA), glycerol and Piperazine (PZ) as well as glycerol and ionic liquid (IL) 1-butyl-3-methylimidazolium dicyanamide ([bmim][DCA]) were determined in this study. It was found that the density and viscosity of the mixtures increased with increasing glycerol concentration. The correlations of density and viscosity of the mixtures were determined as a function of the concentration of glycerol and temperature. For density correlation, the empirical linear equation used in this work showed excellent accuracy with 0.62% as the highest percentage deviation for all the mixtures involved. While for the viscosity correlation, there was a good fit between the mixtures and the extended Arrhenius equation with 9.91% as the highest percentage deviation from the experimental viscosity data. © 2016 Elsevier B.V.

Shamiri A.,University of Malaya | Shamiri A.,Razi Petrochemical Company | Hussain M.A.,University of Malaya | Mjalli F.S.,Sultan Qaboos University | Mostoufi N.,University of Tehran
Chemical Industry and Chemical Engineering Quarterly | Year: 2013

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.

Akbari V.,University of Technology Malaysia | Akbari V.,Razi Petrochemical Company | Borhani T.N.G.,University of Technology Malaysia | Godini H.R.,TU Berlin | Hamid M.K.A.,University of Technology Malaysia
Powder Technology | Year: 2014

A two dimensionally Eulerian-Eulerian multiphase flow model coupled with a population balance modeling (CFD-PBM) simulation was implemented to investigate the fluidization structure in an industrial scale gas phase polymerization reactor (FBR). Direct quadrature method of moments (DQMOM) was employed in this model to solve the PBM. Two cases including perforated distributor and complete sparger have been applied to examine the flow structure through the bed. A simulation of the reactor with perforated distributor was performed first to validate and evaluate the impact of distributor's characteristics on the fluidization behaviors. The predicted results were in good agreement with the industrial data in terms of pressure drop and bed height. The results showed that different heterogeneous flow patterns were created in a perforated distributor, due to more kinetic energy and jet formation above the distributor. A dead zone is expected to be formed near the corners of the perforated distributor. In addition, the cluster formation is expected to be decreased in comparison with the complete sparger plate distributor. Furthermore, the results predicted bigger bubble diameter in the case of the perforated distributor by using an image processing technique. The information obtained from this study could be important to assure efficient industrial operations of FBRs. © 2014 Elsevier B.V.

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