E. I. du Pont Canada Company

Kingston, Canada

E. I. du Pont Canada Company

Kingston, Canada
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Sanaei S.,University of Tehran | Mostoufi N.,University of Tehran | Radmanesh R.,E. I. du Pont Canada Company | Sotudeh-Gharebagh R.,University of Tehran | And 2 more authors.
Canadian Journal of Chemical Engineering | Year: 2010

Effect of temperature on the hydrodynamics of bubbling gas-solid fluidized beds was investigated in this work. Experiments were carried out at different temperatures ranged of 25-600°C and different superficial gas velocities in the range of 0.17-0.78m/s with sand particles. The time-position trajectory of particles was obtained by the radioactive particle tracking technique at elevated temperature. These data were used for determination of some hydrodynamic parameters (mean velocity of upward and downward-moving particles, jump frequency, cycle frequency, and axial/radial diffusivities) which are representative to solids mixing through the bed. It was shown that solids mixing and diffusivity of particles increases by increasing temperature up to around 300°C. However, these parameters decrease by further increasing the temperature to higher than 300°C. This could be attributed to the properties of bubble and emulsion phases. Results of this study indicated that the bubbles grow up to a maximum diameter by increasing the temperature up to 300°C, after which the bubbles become smaller. The results showed that due to the wall effect, there is no significant change in the mean velocity of downward-moving clusters. In order to explain these trends, surface tension of emulsion between the rising bubble and the emulsion phase was introduced and evaluated in the bubbling fluidized bed. The results showed that surface tension between bubble and emulsion is increased by increasing temperature up to 300°C, however, after that it acts in oppositely. © 2010 Canadian Society for Chemical Engineering.


Bashiri H.,University of Tehran | Mostoufi N.,University of Tehran | Radmanesh R.,E.I. Du Pont Canada Company | Sotudeh-Gharebagh R.,University of Tehran | Chaouki J.,Ecole Polytechnique de Montréal
Iranian Journal of Chemistry and Chemical Engineering | Year: 2010

Effect of scale on the hydrodynamics of gas-solid fluidized beds was investigated in two fluidized beds of 152 mm and 78 mm in diameter. Air at room temperature was used as the fluidizing gas in the bed of sand particles. The Radioactive Particle Tracking (RPT) technique was employed to obtain the instantaneous positions of the particles at every 20 ms of the experiments. These data were used to calculate hydrodynamic parameters, such as mean velocity of upward and downward-moving particles, jump frequency, cycle frequency and axial and radial diffusivities, which are representative of solid mixing and diffusion of particles in the bed. These hydrodynamic parameters were compared in both scales in order to determine the scale effect on the hydrodynamics of the gas-solid fluidized bed. In all cases, it was shown that solid mixing and diffusivity of particles increase by increasing column diameter. The results of this study would help to understand solid mixing which might be critical in industrial fluidized bed reactors.


Cui W.J.,Queen's University | Mcauley K.B.,Queen's University | Whitney R.A.,Queen's University | Spence R.E.,E. I. du Pont Canada Company | Xie T.,E. I. du Pont Canada Company
Macromolecular Reaction Engineering | Year: 2013

A mathematical model is developed for condensation polymerization of 1,3-propanediol to produce Cerenol polyether. The effect of the super-acid catalyst is considered explicitly in the proposed reaction mechanism. The main reactions include protonation/deprotonation equilibrium, polycondensation, carbocation formation, end degradation, and transetherification. Formation of propanal and secondary hydroxyl ends is also considered. Mass transfer of water, propanal, and monomer from the liquid phase into nitrogen bubbles is included in the model. The proposed model predicts the time evolution of number average molecular weight and concentrations of water, propanal, monomer, and unsaturated end groups, along with evaporation rates of small molecules. Data from isothermal batch experiments are used to estimate model parameters. Steep upward trends in degree of polymerization and in concentration of unsaturated ends are not predicted well at long reaction times based on the current model. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Cui W.J.,Queen's University | Mcauley K.B.,Queen's University | Spence R.E.,E. I. du Pont Canada Company | Xie T.,E. I. du Pont Canada Company
Macromolecular Reaction Engineering | Year: 2014

A mathematical model is developed to simulate condensation polymerization of 1,3-propanediol to produce polytrimethylene glycol (PO3G) polyether. The model includes improved mass-transfer expressions that account for nonzero concentrations of water and monomer inside nitrogen bubbles and for increasing overall bubble surface area due to increases in bubble residence time. An objective function that accounts for the mole fractions of evaporated monomer, water and propanal is considered for parameter estimation. Improvements in the predicted monomer and water concentrations in the polymer and evaporation rates of monomer and water can be observed compared to a previous model. However, predictions of degree of polymerization do not improve noticeably. Recommendations including revisions of the chemical mechanism to include additional reactions and accounting for evaporation of linear and cyclic oligomers in future models are suggested. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Cui W.J.,Queen's University | McAuley K.B.,Queen's University | Spence R.E.,E. I. du Pont Canada Company | Xie T.,E. I. du Pont Canada Company
Macromolecular Reaction Engineering | Year: 2015

A mathematical model is developed to simulate the production of bio-based polytrimethylene ether glycol (PO3G) using 1,3-propanediol. The effect of super-acid catalyst is accounted for in the model, as is mass transfer of small species (water, monomer, and propanal) and linear oligomers (dimer to heptamer). This model correctly predicts dynamic trends in concentrations of linear oligomers, but the predicted maxima in these concentrations appear slightly earlier than in the experimental data. Predictions of the degree of polymerization (DP) are improved compared with those from a previous model, where evaporation of linear oligomers was not considered. Additional model improvements, including accounting for the effects of cyclic oligomers, are suggested. A reactor model is developed to simulate the production of Cerenol® polyethers. The effects of super-acid catalyst and mass transfer of small species (water, monomer, propanal) and linear oligomers (dimer to heptamer) have been modeled. This model correctly predicts the dynamic trends in the concentration changes of linear oligomers, but the predicted maxima in these concentrations appear earlier compared with those from a previous model. The Dp is greatly improved compared with a previous model, where the evaporation of linear oligomers is not considered. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Khatamian M.,University of Tabriz | Daneshvar N.,University of Tabriz | Sabaee S.,University of Tabriz | Radmanesh R.,E.I. Du Pont Canada Company
Iranian Journal of Chemistry and Chemical Engineering | Year: 2010

The photocatalytic decolorization of aqueous solutions Brown NG, a commercial textile dye, was studied using titana Degussa P-25 as a catalyst for the first time. The experiments were carried out in a batch reactor with the use of artificial light sources (UV-C). The effects of various process variables on decolorization performance of the process have been investigated. The photodegradation of Brown NG was enhanced by the addition of proper amounts of hydrogen peroxide, but it was inhibited by ethanol. Inhibiting effect of ethanol showed that hydroxyl radicals play a significant role in the photodegradation of the dye. In addition, the decolorization efficiency increased with decrease in pH, which implies that the pH is a very important parameter in dye adsorption. The efficiency is inversely related to the dye concentration. Results of TOC analysis show that the organic compounds were degraded, too.

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