in the current work, ethylene polymerization was investigated from a mathematical modeling point of view. the initiation (activation), propagation, termination, and deactivation reactions were taken into account and the relevant equations used in the modeling were obtained from the elementary reactions. some assumptions including neglecting the transfer and deactivation reactions were considere...

using surface analysis, simultaneous effects of temperature (260-380ºc) and ethanol concentration (0-1%) on dimethyl ether (dme) selectivity, yields of hydrocarbon and dme, and methanol conversion were investigated in methanol dehydration reaction over γ-al2o3 catalyst. methanol conversion and yield of hydrocarbon/dme were found to be significantly affected by temperature and the temperature-et...

Although catalyst deactivation rate greatly varies depending on many factors, including the catalyst structure, reactor feed composition, and operating conditions; it is usually inevitable. Since catalyst deactivation modeling has so far been poorly addressed in the literature, in the present study, nine experimental sets of cobalt based Fischer-Tropsch catalysts activity-time data were conside...

Catalyst activity and performance are the most important factors for selecting a catalyst in different processes. The Fischer-Tropsch synthesis is a very important synthesis that extensive action has been taken place to increase the activity of its catalysts in the recent century. Deactivation of the catalysts of the process is influenced by many factors, among which coking and sintering have c...

in the present study, tin-promoted pd/mwnts nanocatalystwas synthesized via polyol technique for application in hydrogenation of high-concentrated acetylene feedstocks. tem images showed a restricted distribution of nanoparticles in the range of 3-5 nm. the results indicated that nanoparticles sizes were resistant to further catalyst deactivation. xrd patterns signified alloying between pd and ...

Understanding the di usion and activation of arsenic is critical for the formation of low resistance ultra-shallow junctions as required for nanoscale MOS devices. In this work, we use results of ab-initio calculations in order to gain insight into the fundamental processes in volv edin arsenic activation/deactivation. Utilizing continuum modeling, we nd it is possible to accoun t for both the ...

Ordinary differential equations are coupled with mixed constrained optimization problems when modeling the thermodynamic equilibrium of a system evolving with time. A particular application arises in the modeling of atmospheric particles. Discontinuity points are created by the activation/deactivation of inequality constraints. A numerical method for the solution of optimization-constrained dif...