Modeling and Simulation
M. Hosseini; A. H. Oudi; Y. Davoodbeygi
Abstract
The fully mixed continuous stirred tank reactor is an important type of industrial reactors mainly used to produce high volume products such as petrochemicals, detergents, sanitary products and products that are in demand in the market. Knowing the dynamic behavior of chemical reactors is of great importance ...
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The fully mixed continuous stirred tank reactor is an important type of industrial reactors mainly used to produce high volume products such as petrochemicals, detergents, sanitary products and products that are in demand in the market. Knowing the dynamic behavior of chemical reactors is of great importance in setting up, designing, controlling and stopping reactors. In this paper, the effect of non-dimensional numbers Damkohler and Stanton on the stability of a continuous stirred tank reactor in which a first-order exothermic reaction takes place is investigated. First, a mathematical model of the system's dynamic behavior was presented. Then, by simultaneous solving of the equations of mass and energy around the fixed point in MATLAB software, the effect of the mentioned numbers was investigated. The results show that the continuous stirred tank reactor shows different behaviors in different ranges of Damkohler and Stanton numbers. This reactor behaves unstable in small and large ranges of Damkohler and Stanton numbers due to the presence of mixed or positive and negative eigenvalues. The best range for Damkohler and Stanton numbers is close to 1, because in this range the reactor shows stable behavior due to having two negative eigenvalues. In this range, in addition to the stability, the conversion is also 100%. Finaly the ratio of Stanton to DamKohler was investigated as St / Da˃1 and St / Da = 1. If St / Da = 1, the system is in steady state, but in St / Da˃1, the system moves away from steady state.
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.