Iranian Journal of Chemical Engineering (IJChE)

Abstract Total combustion of methyl ethyl ketone and benzyl alcohol as two models of volatile organic compounds (VOCs) using catalytic method was studied over γ-Al2O 3 and Mn/γ-Al2O 3 catalysts. Catalyst (Mn/γ-Al2O 3) was prepared by wet impregnation and characterized using XRD, BET, ICP-AES and SEM methods and the nanostructure of the catalyst were approved. The activity of the catalysts was measured in a catalytic packed bed reactor under atmospheric pressure and different reaction temperatures at range 150 to 450°C. The studies confirmed that manganese supported on γ-Al2O 3 can be suitable for the abatement of the mentioned pollutants from contaminated air and hopefully holds the promise for the elimination of VOC containing hazardous materials in industrial applications.

Abstract This paper reports the result of CFD simulation of catalytic oxidation of benzene on monolithic catalyst. The geometries ofthe catalyst and reactor were designed in Gambit software and simulation of catalytic oxidation was carried out in fluent 6.2. Results of simulation showed excellent agreement with the experimental data. This study confirmed the accuracy of the used model in this simulation (Mars van Krevelen). Furthermore, CFD made it possible to obtain a more accurate view ofheat transfer and fluid flow. This study confirmed CFD is the best tool for study offluid regime and heat transfer and especially, concentration of species, and surface deposition along the reactor in the chemical process.

Abstract The effectiveness of binary mixtures of phosphorus and sulfur compounds as coke inhibitors for naphtha pyrolysis has been studied. As both phosphorus and sulfur compounds proved to be promising coke inhibitors, runs were made with mixtures of these compounds. The coke deposited was significantly lower when phosphor was used together with sulfur. Also, the effect of the addition of K₂CO₃ and K₂CO₃ in the naphtha feed was investigated. It was found that the addition of Na₂CO₃ and K₂CO₃ reduced the coke formation. Scanning electron microscope (SEM) was used for the
microstructure of deposited coke and energy dispersive X-Ray spectroscopy (EDAX) for the surface elemental composition of coke formed on the surface of stainless steel coupons. It was found that in the presence of inhibitors, deposited coke has a porous structure and so small amounts of Ni , Cr , and Fe elements.

Abstract An industrial ethane thermal cracking reactor was modeled assuming a molecular mechanism for the reaction kinetics coupled with material, energy, and momentum balances of the reactant-product flow along the reactor. To carry out the multi-objective optimization for two objectives such as conversion and ethylene selectivity, the elitist non-dominated sorting genetic algorithm was used. The Pareto optimum set was obtained successfully and finally the effect of the decision variable was discussed.
 
 

Abstract A study on coke deposition and coking inhibitors during naphtha pyrolysis was made in a jet stirred reactor system. This system is noted for its simple structure, easy alteration of operating parameters, small volumes of feedstock used for pyrolysis, high accuracy of coke formation measurements, and short operating cycle. It is also particularly suitable for identifring coking inhibitors over a wide range of conditions. The effect of the addition of CS2, DMS, DMDS and Disulfideoil in the naphtha feed was investigated. It was found that for a given concentration of sulfa. in the feed, the asymptotic coking rate decreases in the order: Dimethyl disulfide > Disulfideoil > Dimethyl sulfide > Carbon disulfide. Scanning electron microscope (SEM) was used for the microstructure of deposited coke and energy dispersive X-Ray spectroscopy (EDAX) for the surface elemental composition of coke formed on the surface of stainless steel coupons. It was found that in the presence of inhibitors, deposited coke has a porous structure and small amounts of Ni, Cr, and Fe elements. Based on our results, this paper aims to provide a closer insight into the coking problem in industrial steam crackers.