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RISS 인기검색어
- 검색키워드
- 저자 : Sepehr Sadighi (검색결과 4 건)
- 무료
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4-Lump kinetic model for vacuum gas oil hydrocracker involving hydrogen consumption
Sepehr Sadighi,Arshad Ahmad,Mehdi Rashidzadeh 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.4
A 4-lump kinetic model including hydrogen consumption for hydrocracking of vacuum gas oil in a pilot scale reactor is proposed. The advantage of this work over the previous ones is consideration of hydrogen consumption,imposed by converting vacuum gas oil to light products, which is implemented in the kinetic model by a quadratic expression as similar as response surface modeling. This approach considers vacuum gas oil (VGO) and unconverted oil as one lump whilst others are distillate, naphtha and gas. The pilot reactor bed is divided into hydrotreating and hydrocracking sections which are loaded with different types of catalysts. The aim of this paper is modeling the hydrocracking section, but the effect of hydrotreating is considered on the boundary condition of the hydrocracking part. The hydrocracking bed is considered as a plug flow reactor and it is modeled by the cellular network approach. Initially,a kinetic network with twelve coefficients and six paths is considered. But following evaluation using measured data and order of magnitude analysis, the three route passes and one activation energy coefficient are omitted; thus the number of coefficients is reduced to five. This approach improves the average absolute deviation of prediction from 7.2%to 5.92%. Furthermore, the model can predict the hydrogen consumption for hydrocracking with average absolute deviation about 8.59% in comparison to those calculated from experimental data.
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A two-dimensional discrete lumped model for a trickle-bed vacuum gas oil hydrocracking reactor
Sepehr Sadighi 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.9
A two-dimensional (2D) computational fluid dynamics model based on discrete lumping approach was used to predict the product yields of a pilot scale vacuum gas oil (VGO) hydrocracking reactor. This model was developed by solving mass conservation equations in conjunction with the continuity and momentum balances in the z-r cylindrical plane. The kinetic parameters of the model were estimated from the experimental data, and validated by using actual values. Results show that the proposed model can appreciably improve the accuracy of the yield prediction in comparison to the predicted value using the 1D model. Moreover, it is confirmed that the order of magnitude of the radial liquid velocity against the axial one is considerably low, and there is no significant pressure drop along the r-direction. Additionally, results show that two-dimensional model is a reliable tool for evaluating the catalyst performance and also for designing commercial reactors.
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Investigating the Cold Plasma Surface Modification of Kaolin- and Attapulgite-Bound Zeolite A
Mahboobeh Ejtemaei,Sepehr Sadighi,Mehdi Rashidzadeh,Sirous Khorram,Jan O. Back,Simon Penner,Michael F. Noisternig,Dariush Salari,Aligholi Niaei 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.106 No.-
Hydrophilic zeolites with low catalytic activity are considered as suitable adsorbents for drying gasstreams containing olefinic compounds. In this contribution, the surface treatment of kaolin and attapulgite/zeolite A extrudates is investigated using argon glow discharge plasma. The zeolite is synthesizedfrom kaolin using the hydrothermal method. Surface and bulk characterization is performed using X-raydiffraction (XRD), scanning electron microscopy (SEM), N2 physisorption, Fourier-transform infrared (FTIR)spectroscopy, temperature-programmed-desorption (TPD) of NH3 and X-ray photoelectron spectroscopy(XPS) techniques. Plasma treatment increases surface area and pore volume, but it decreasesthe weak acidic site density of the extrudates. The obtained results show that attapulgite/zeolite extrudatesare more affected by plasma treatment than kaolin/zeolite extrudates. The catalytic activity ofuntreated and plasma-treated extrudates are compared with respect to coke formation resulting from1-butene and 1,3-butadiene. The plasma-treated sample is more resistant to coke formation (35%decrease compared to untreated one). The potassium contents of extrudates decreased as a result of sputteringloosely bound potassium cations on the crystal surface by argon ions, which led to a decrease inwater sorption capacity (by 15% of the initial sorption capacity).
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Reza Hayati,Sorood Zahedi Abghari,Sepehr Sadighi,Mahmood Bayat 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.4
The isomerization process is a substantial technology to produce clean fuel from linear paraffinic speciesexisting in light naphtha. We investigated the influence of hydrocracking reactions besides the other reactions on theresearch octane number (RON) of the isomerization product. A reaction network and a kinetic model including fifteenlumps and sixteen reactions were developed. Several experiments were carried out in a pilot plant to estimatekinetic parameters. The accuracy of the model was evaluated by comparing the model prediction with the experimentalresults. The maximum RON and process yield were strongly dependent on the temperature, hydrogen to hydrocarbonmolar ratio (H2/Oil) and liquid hourly space velocity (LHSV). Also, increasing the reaction temperature compensatedfor the negative effects of raising the LHSV and H2/Oil in RON maximization. Moreover, we concluded thatthe hydro cracking reactions were very effective on RON, such that they can dominate the role of the other reactions. By sensitivity analysis in this research, a rule was obtained to declare the effect of operating condition on maximizationof RON and the method of revamping of naphtha isomerization reactor.
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