Sharif Digital Repository

In this report, the efficacy of different factors such as temperature of reaction, time of reaction and depth of bed are investigated in a process of recovery of zinc oxide from zinc ore concentration residues in a fluidized bed furnace. Under optimum conditions, there was more than 93.5% zinc oxide in products  

In this research a mathematical model for direct oxidization of hydrogen sulfide into elemental sulfur in a fluidized bed reactor with external circulation was developed. As the catalyst is deactivated in the fluidized bed, it might be placed in a reduction tank in order to remove sulfur through heating above its dew point. The reactor model demonstrated via MATLAB software. It was shown that variations of H 2S conversion as well as; products formed were reasonable in comparison with corresponding results of a fixed bed reactor. Through analyzing results of this model, it became possible to propose the main optimized operating conditions for the process considered. These conditions included;... 

In this research, a mathematical model to simulate a two-phase fluidized bed reactor for oxidative dehydrogenation of propane to propylene was developed. The developed model was solved numerically using the matlab software. Moreover, effects of the reaction temperature, operating pressure, feed composition, particle's size and gas superficial velocity on the reactant conversion, product selectivity and desired product's yield were understudied. The model was validated using previously published experimental data for simulation of the case at the exit of the circulating fluidized bed reactor. The results revealed that, as the temperature raised from 783 to 823 K, the propane conversion... 

In this article, a standard 2D Two-Fluid Model (TFM) closed by the kinetic theory of granular flow (KTGF) has been applied to simulate the behavior of tapered-in and tapered-out fluidized bed reactors. In this regard, two types of chemical reactions with gas volume reduction and increase were considered to investigate the effects of initial static bed height on the fractional conversion and bed pressure drop. To validate the CFD model predictions, the results of hydrodynamic simulations concerning bed pressure drop and bed expansion ratio were compared against experimental data reported in the literature and excellent agreement was observed. The obtained simulation results clearly indicate... 

This article presents a simulation study of tapered-in and tapered-out fluidized bed reactors to investigate the influences of apex angle on the fractional conversion and the pressure drop of the fluidized beds in the presence of two types of chemical reaction with gas volume increase and reduction. The 2D behavior of tapered-in and -out fluidized beds was also compared with a columnar one from fractional conversion and bed pressure drop point of views. To validate the simulation results, the numerical predictions for the expansion ratio and the pressure drop of a tapered fluidized bed were compared with experimental data and good agreement was observed. The obtained simulation results... 

This article presents a simulation study of tapered-in and tapered-out fluidized bed reactors to investigate the influences of apex angle on the fractional conversion and the pressure drop of the fluidized beds in the presence of two types of chemical reaction with gas volume increase and reduction. The 2D behavior of tapered-in and -out fluidized beds was also compared with a columnar one from fractional conversion and bed pressure drop point of views. To validate the simulation results, the numerical predictions for the expansion ratio and the pressure drop of a tapered fluidized bed were compared with experimental data and good agreement was observed. The obtained simulation results... 

This article presents a simulation study of tapered-in and tapered-out fluidized bed reactors to investigate the influences of apex angle on the fractional conversion and the pressure drop of the fluidized beds in the presence of two types of chemical reaction with gas volume increase and reduction. The 2D behavior of tapered-in and -out fluidized beds was also compared with a columnar one from fractional conversion and bed pressure drop point of views. To validate the simulation results, the numerical predictions for the expansion ratio and the pressure drop of a tapered fluidized bed were compared with experimental data and good agreement was observed. The obtained simulation results... 

The aim of this study is to assess the influence of oxygen-to-steam ratio, wall boundary conditions, coal feeding rate, and static bed height on the concentrations, heating values, and efficiencies of the product gas in a tapered fluidized bed reactor. Results show that lower and higher heating values slightly vary with increasing the oxygen-to-steam ratio in the range of 0.25–0.35. It is found that cold gas efficiency and carbon conversion efficiency goes up with increased ratio of oxygen to steam; however, both efficiencies decline as a result of increasing the coal feeding rate. As static bed height rises, lower and higher heating values diminish for tapered angle of 5°. For tapered angle... 

In this research a mathematical model for direct oxidization of hydrogen sulfide into elemental sulfur in a fluidized bed reactor with external circulation was developed. As the catalyst is deactivated in the fluidized bed, it might be placed in a reduction tank in order to remove sulfur through heating above its dew point. The reactor model demonstrated via MATLAB software. It was shown that variations of H 2S conversion as well as; products formed were reasonable in comparison with corresponding results of a fixed bed reactor. Through analyzing results of this model, it became possible to propose the main optimized operating conditions for the process considered. These conditions included;...