Sharif Digital Repository

In this paper, optimization and control of a tubular reactor for thermal bulk post-polymerization of styrene have been investigated. By using the reactor mathematical model, static and dynamic simulations are carried out. Based on an objective function including polymer conversion and polydispersity, reactor optimal temperature profile has been obtained. In the absence of model mismatch, desired product characteristic can also be obtained by applying the corresponding reactor wall or jacket temperature profile. To achieve this temperature trajectory, reactor jacket is divided into three zones and jacket inlet temperatures are used as manipulated variables. Effectiveness of the proposed... 

In this article, the problem of simultaneous heat, mass, and momentum transfer in the developing region of tubular reactors with homogeneous chemical reaction and laminar power-law fluid flow under unsteady-state conditions has been solved. In this regard, the general governing equations were solved using finite-difference method and analyzed carefully. Moreover, the influences of various parameters and dimensionless numbers such as power-law index, heat of reaction, reaction order, and Damköhler number value on the numerical results were investigated. In addition, the numerical results obtained for the fully-developed velocity distribution of Newtonian fluid flow and Sherwood number value... 

Due to advantages of tubular polymerization reactors, a tubular reactor was used as the postpolymerizer for thermal bulk polymerization of styrene. By solving the mathematical model, static and dynamic simulations were carried out to study the reactor's behavior. In order to have a desired product regarding the monomer conversion and polydispersity at the reactor outlet, a specific temperature profile must be kept along the reactor's length. Based on the desired profile and using the system model, a trajectory for the jacket temperature was obtained. To apply the desired jacket temperature, the jacket is divided into three zones. The set-point of each zone has been obtained by discretizing... 

Oxidative coupling of methane in a bench scale fixed bed tubular reactor over Mn-Na2WO4/SiO2 catalyst has been studied. Four kinetic models have been considered for oxidative coupling of methane reactions and compared through experimental data, and the best kinetic model has been selected. For removing the heat of reaction, a molten salt bath system surrounding the reactor tube has been proposed. Effects of different factors, such as CH4/O2 ratio, are investigated through experimental and simulation studies. A good agreement has been observed between simulation and experimental data. The reactor behaviors under isothermal and adiabatic conditions have also been simulated  

A comparison of various hydrogen production processes indicates that the thermal decomposition of methane (TDM) provides an attractive option from both economical and technical points of view. The main problem for this process is the deposition of the nano-carbon particles on the reactor wall (or catalyst surface). This research concentrates on the numerical simulation of the TDM process without use of a catalyst to find a technique that decreases the carbon accumulation in a tubular reactor. In this model, the produced carbon particles are tracked with the Lagrangian method under thermophoretic, Brownian, van der Waals, Basset, drag, lift, gravity, pressure and virtual mass forces. In...