M.E zeynali; H. Abedini; H. R. Sadri
Volume 16, Issue 3 , September 2019, , Pages 23-36
Abstract
Divinylbenzene (DVB) is produced by catalytic dehydrogenation of DEB at high temperature and atmospheric pressure. Ethylvinylbenzene (EVB) is produced as a useful chemical during dehydrogenation of DEB. Also some other liquid and gaseous by products is produced during dehydrogenation. A set-up has been ...
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Divinylbenzene (DVB) is produced by catalytic dehydrogenation of DEB at high temperature and atmospheric pressure. Ethylvinylbenzene (EVB) is produced as a useful chemical during dehydrogenation of DEB. Also some other liquid and gaseous by products is produced during dehydrogenation. A set-up has been developed to conduct the DEB dehydrogenation reactions experiments to prepare DVB at different conditions. Model equations for DEB dehydrogenation reactor have been solved by genetic algorithm (GA) method using MATLAB software. Reaction rate constants and absorption coefficients were determined at various temperatures. The conversion of DEB and ethylvinyl benzene (EVB) in the reactor was predicted by mathematical modeling and compared with experimental results. The comparison shows good agreements between experimental and modeling results. The combined effects of DEB flow rate and catalyst weight as time factor were investigated on conversion of DEB and production of EVB and DVB. Effects of temperature on consumption of DEB and production of EVB and DVB in the tubular reactor were investigated.
Reaction Engineering, Kinetics and Catalysts,
M. E. Zeynali; H. Abedini; H. R. Sadri
Volume 15, Issue 4 , November 2018, , Pages 93-104
Abstract
DEB dehydrogenation reaction was conducted to produce divinylbenzene (DVB) and ethylvinylbenzene (EVB). The effects of temperature, catalyst weight and time factor on the performance of the dehydrogenation reactor were investigated experimentally. Temperature was varied from 550º C up to 600 º ...
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DEB dehydrogenation reaction was conducted to produce divinylbenzene (DVB) and ethylvinylbenzene (EVB). The effects of temperature, catalyst weight and time factor on the performance of the dehydrogenation reactor were investigated experimentally. Temperature was varied from 550º C up to 600 º C. Temperature affect the conversion of DEB to DVB significantly. The mole fraction of DEB in the outlet of the reactor is reducing up to 580 º C, but further increase in temperature up to 600 º C does not decrease the mole fraction of DEB in the outlet of the reactor. Catalyst weight was varied from 10 gr up to 40 gr. The results showed that the trends of EVB+DVB production and DEB consumption are identical at various catalyst weights. To obtain optimum time factor for the DEB dehydrogenation process experiments were conducted at various time factors. The results showed that the optimum time factor for DVB as a desired product is 825 gr/hr.mole. . The data and information provided in this research can be used for scale-up and optimization purposes.
Modeling and Simulation
M.R zeynali; M. Nazari; S. Karimi; S. M. Seyedmohaghegh; S. Soltani
Volume 14, Issue 2 , 2017, , Pages 3-16
Abstract
In this research samples of PVOH were synthesized at various reaction conditions (temperature, time, and amount of catalyst). First at 25˚C and 45˚C and constant catalyst weight samples of PVOH were prepared with different degree of hydrolysis at various times. For investigation of the effects of temperature, ...
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In this research samples of PVOH were synthesized at various reaction conditions (temperature, time, and amount of catalyst). First at 25˚C and 45˚C and constant catalyst weight samples of PVOH were prepared with different degree of hydrolysis at various times. For investigation of the effects of temperature, at times 20 and 40 min and constant weight of catalyst PVOH was prepared at various temperatures. Increasing the time and temperature of the hydrolysis reaction caused increasing degree of hydrolysis and reducing the molecular weight of the samples. Considering the variation of reaction condition, the effects of each parameter on molecular weight, degree of hydrolysis and conversion were investigated individually and also collective. Also, by an artificial neural network method, using experimental results (temperature, time and catalyst amount as input and conversion, degree of hydrolysis and molecular weight as output) a network by Levenberg-Marquardt (LM) back propagation with tan-sigmoid transfer function was established. Finally, the established model presented a good prediction capability and enabled us to predict the output in terms of arbitrary in puts. PVOH is an important polymer and prediction its properties during production significantly improves the quality of the products. Neural network technique is used to model the chemical processes to predict the behavior of the process. In this research we investigated the effects of various processing parameters on the properties of PVOH.