Wastewater treatment using photo-impinging streams cyclone reactor: Computational fluid dynamics and kinetics modeling

Sayed Javid Royaee,Morteza Sohrabi,Amin Shafeghat 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.2

A photo impinging streams cyclone reactor has been used as a novel apparatus in photocatalytic degradationof organic compounds using titanium dioxide nanoparticles in wastewater. The operating parameters, includingcatalyst loading, pH, initial phenol concentration and light intensity have been optimized to increase the efficiency ofthe photocatalytic degradation process within this photoreactor. The results have demonstrated a higher efficiency andan increased performance capability of the present reactor in comparison with the conventional processes. In the nextstep, residence time distribution (RTD) of the slurry phase within the reactor was measured using the impulse tracermethod. A CFD-based model for predicting the RTD was also developed which compared well with the experimentalresults. The RTD data was finally applied in conjunction with the phenol degradation kinetic model to predict theapparent rate coefficient for such a reaction.

A comprehensive study on wastewater treatment using photo-impinging streams reactor: Continuous treatment

Sayed Javid Royaee,Morteza Sohrabi,Narges Fallah 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.11

The degradation of phenol was investigated in a continuous flow impinging streams system. In the first step, statistical experimental designs were used to optimize the process of phenol degradation in a photo-impinging streams reactor. The more important factors affecting phenol degradation (p<0.05) were screened by a two-level Plackett-Burman design. Four of the latter parameters, namely phenol concentration, catalyst loading, pH and slurry flow rate,were selected for final process optimization, applying central composite design (CCD). The predicted data showed that the maximum removal efficiency of phenol (99%) could be obtained under the optimum operating conditions (phenol concentration=50 mg l−1, catalyst loading=2.1 g l−1, pH 6.2 and slurry flow rate=550ml min−1). These predicted values were then verified by certain validating experiments. A good correlation was observed between the predicted data and those determined by the experimental study. This may confirm the validity of the statistical optimum strategy. Finally,continuous degradation of phenol was performed, and the results indicated a higher efficiency and an increased performance capability of the present reactor in comparison with the conventional processes.

Degradation of phenol by heterogeneous Fenton reaction using Fe/clinoptilolite

Maryam Bayat,Sayed Javid Royaee,Morteza Sohrabi 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.3

A novel heterogeneous catalyst for degradation of phenol has been synthesized. Dispersed metallic clusters of iron loaded on to clinoptilolite by impregnation method. Clinoptilolite belongs to the broad family of natural zeolites. The influences of pH, the mass ratio of iron to clinoptilolite, the ratio of hydrogen peroxide to phenol and catalyst loading on phenol degradation were investigated. An autocatalytic heterogeneous–homogeneous kinetic model was proposed for this reaction. Experiments were performed, using a stirred batch reactor under mild conditions with 100 mg L1 initial phenol concentration applying Fe/clinoptilolite as a catalyst and H2O2 as an oxidant. This new heterogeneous Fenton-like system resulted in a nearly total elimination of phenol and 70% COD removal during 30 min. In order to examine the effect of run time on the activity and stability of the catalyst, the degradation reaction was carried out applying a continuous packed bed reactor. It was observed that during 30 h time on stream no change in the activity of the catalyst or any structural deformation of the particles was occurred. A negligible release of iron from the catalyst during the reaction (6 ppm) may be related to the appropriate stability of the latter.

Synthesis and activity measurement of the some bifunctional platinum loaded Beta zeolite catalysts for n-heptane hydroisomerization

Goodarz Talebi,Sayed Javid Royaee,R.L. Keiski,M. Huuhtanen,Hamid Imamverdizadeh,Morteza Sohrabi 한국공업화학회 2008 Journal of Industrial and Engineering Chemistry Vol.14 No.5

In this study, two types of Beta zeolites having different Si/Al ratios (11.7 and 24.5) were synthesized hydrothermally using tetraethyl ammonium hydroxide (TEAOH) as a template. Different amounts of platinum (0.2%, 0.5% and 1.2%) were loaded on the protonated form of zeolite by incipient wet impregnation method applying hexachloroplatinic acid in 0.2N Cl progressive ion solutions. Catalytic hydroisomerization reactions were carried out at atmospheric pressure in a fixed bed reactor with vertical placing and downward flow at three different temperatures, various WHSV (weight hourly space velocity) and n-H2/n-HC (molar hydrogen/hydrocarbon) ratio. Increase in Si/Al ratio in zeolites structures from 11.7 to 24.5 promoted selectivity and yield. It was found that optimum platinum content depends on the Si/Al ratio (zeolite acidity) in catalysts. Monobranched to dibranched isomers ratio were correlated with a linear function of n-heptane conversion. Such a correlation was found to be valid for various Si/Al ratios, metal content, processing temperature and pressure, WHSV and hydrogen to hydrocarbon ratio. This observation may indicate that in isomerization reactions, the monobranched isomers are first produced but subsequently transformed into multibranched isomers.

Application of nano-sized cobalt on ZSM-5 zeolite as an active catalyst in Fischer–Tropsch synthesis

Marjan Dalil,Sayed Javid Royaee,Morteza Sohrabi 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.2

In this study the catalytic behavior of Co/HZSM-5 in Fischer–Tropsch synthesis (FTS) has been examined in order to optimize the operating conditions for acquiring maximum selectivity. Catalysts consisted of various quantities of cobalt particles supported on HZSM-5 zeolite were prepared by impregnation method. In order to investigate the effects of operating parameters on catalytic performance and to estimate the optimum conditions, experiments were designed using L-16 Taguchi method. All experimental runs were carried out in a fixed bed reactor under isobaric condition (2 MPa). According to the Taguchi model and considering the impact of the operating parameters on the process output and performing certain validation tests, the optimum operating conditions for the process were determined as T = 513 K, space velocity = 1.1 h1, Co on HZSM-5 = 11.6%, H2/CO = 1.7. In the next step, a kinetic model for FTS based on carbide mechanism was presented applying the synthesized catalyst under the optimum conditions. This model is a combination of kinetic rates of hydrocarbon formation and the relations for the growth probability and olefin re-adsorption factor.

Isobutane aromatization in the presence of propane as a co-reactant over H-ZSM-5 catalysts using different crystallization times

Soroush Baradaran,Morteza Sohrabi,Parsia Moghimpour Bijani,Sayed Javid Royaee 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.27 No.-

Co-Aromatization of isobutane and propane over H-ZSM-5 and Zn/ZSM-5 catalysts prepared by differentcrystallization time ranging from 24 h to 96 h at 180 8C was studied. The samples were characterized viaXRD, BET, SEM and NH3-TPD. A maximum for crystallinity was observed at 72 h with 98% and Acidityalong with crystal size increased with time. Performance tests in a fixed bed reactor at 550 8C showedthat catalytic activity increased with crystallization time while the aromatics selectivity increased withcrystallinity. The results also indicated that conversion of propane in the presence of isobutane wasdramatically lower than individual propane test.

Non-catalytic oxidative desulfurization of gas condensate by ozone and process optimization using response surface methodology

Mehdi Alibolandi,Jafar. Towfighi. Darian,Maryam Ghaedian,Sayed Javid Royaee,Amin Shafeghat 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.11

This study modelled and optimized the oxidative desulfurization of gas condensate with ozone, as a gaseous oxidant. Experiments in this study were non-catalytic, and sulfone extraction was done by acetone. Response surface methodology was applied for the experimental design, mathematical modeling, and optimization using Design- Expert® software. The influence of effective variables and their interaction on the response was also investigated. For the first time, non-catalytic ozonation of this feed was performed on the oxidative desulfurization process. The developed model properly fitted the experimental results. The accuracy of the model was confirmed, while this model predicted 95% desulfurization would result in the optimized conditions, and the actual value of desulfurization obtained was 95.8%. Further, the results indicated interaction between the superficial gas velocity of ozone and coefficient of oxidant- to-sulfur molar ratio. GC-SCD revealed that DBT was the most refractory component in comparison with the other sulfur components in the gas condensate. It was also found that 84.3% desulfurization occurred just with oxidation and sedimentation of sulfones and without solvent extraction.