Design of new activated carbon based adsorbents for improved desulfurization of heavy gas oil: experiments and kinetic modeling

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Amer T. Nawaf ◽  
Aysar T. Jarullah ◽  
Shymaa A. Hameed ◽  
Iqbal M. Mujtaba

Abstract In this work, adsorption desulfurization is considered for making cleaner fuel. New efficient adsorbents have been designed by using two active metal oxides mainly potassium permanganate (KMnO4) and potassium phosphate (KPO4·3H2O) on Activated Carbon (AC). Ultrasonic assisted impregnation method (IWI) is used in designing the adsorbents offering high pore volume, pore size, surface chemistry, and high surface area. Use of ultrasonic method increases the dispersion of the active material (groups) on AC leading to increased number of collisions between O-atom on AC-support resulting in high sulfur removal from fuel. KMnO4 on AC shows higher adsorption capacity towards sulfur than KPO4·3H2O at the same operating conditions. New results with respect to sulfur removal has obtained compared with those obtained by previous studies. Finally, the adsorption kinetic parameters of such process are developed. Thomas and Yoon–Nelson models and the experimental data are used for this purpose using linear and non-linear regression analysis. Yoon–Nelson kinetic model fits well with the experiments data better than Thomas kinetic model in the entire adsorption column system.

2020 ◽  
Vol 1002 ◽  
pp. 423-434 ◽  
Author(s):  
Muayad A. Shihab ◽  
Amer Talal Nawaf ◽  
Shaho A. Mohamedali ◽  
Mazin N. Alsalmaney

This work was focused on the removal of sulfur compounds via adsorption process from heavy naphtha using alkali agents-activated carbon nanotubes (ACNTs). Commercial CNTs were activated using three alkali agents (KOH, NaOH, and CaCl2) to amend their surfaces for application in the petroleum industry. The characterization of the physicochemical properties of as-received CNTs and CNTs/alkali agents was performed using a scanning electron microscope (SEM), N2 adsorption/desorption isotherm, and Fourier transform infrared spectroscopy (FTIR). The effects of three operating conditions including adsorbent dosage (1-3 g), agitation speed (330-1500 rpm), and contact time (30-70 min) on the removal efficiency of sulfur compounds at constant pressure and temperature were investigated. Studying of the removal efficiency at different operating conditions was adopted to effectively evaluate the surface modifications of adsorbents on the present process. The specific surface areas of the CNTs were found to be increased upon treatment with alkali agents especially KOH and NaOH. SEM images demonstrated the formation of many defects on the CNTs surface due to the strong etching effect of both alkali agents KOH and NaOH. FTIR spectra showed different relative intensities around band 3440 cm-1 for CNTs/KOH and CNTs/NaOH which was potentially attributed to the presence of hydroxyl functional groups. The sulfur removal experiments from heavy naphtha (initially had a sulfur concentration of 350 ppm) showed that the largest sulfur removal efficiency and adsorption capacity were 69.6% and 6.6 mg/g adsorbent respectively and obtained with CNTs/KOH which presented a superior adsorption efficiency over others. The highest sulfur removal efficiency was gained at adsorbent dosage=3 g, agitation speed=1500 rpm, and contact time=70 min. The study of adsorption kinetics demonstrated that the adsorption of organosulfur compounds from heavy naphtha obeyed the pseudo-second order kinetics


2020 ◽  
Vol 21 (1) ◽  
pp. 23-31
Author(s):  
Hussam Jumaah Mousa ◽  
Hussein Qasim Hussein

The present research was conducted to reduce the sulfur content of Iraqi heavy naphtha by adsorption using different metals oxides over Y-Zeolite. The Y-Zeolite was synthesized by a sol-gel technique. The average size of zeolite was 92.39 nm, surface area 558 m2/g, and pore volume 0.231 cm3/g. The metals of nickel, zinc, and copper were dispersed by an impregnation method to prepare Ni/HY, Zn/HY, Cu/HY, and Ni + Zn /HY catalysts for desulfurization. The adsorptive desulfurization was carried out in a batch mode at different operating conditions such as mixing time (10,15,30,60, and 600 min) and catalyst dosage (0.2,0.4,0.6,0.8,1, and 1.2 g). The most of the sulfur compounds were removed at 10 min for all catalyst types. The maximum sulfur removal was 56% using (Ni+Zn)/HY catalyst at 1.2 g dose for 24 h. The adsorption kinetics and isotherm of sulfur removal were studied, and results indicated that desulfurization adsorption kinetic was 2nd order, and Temkin and Freundlich models were the best representation isotherm.


2020 ◽  
Vol 38 (10A) ◽  
pp. 1441-1453
Author(s):  
Yusra A. Abd Al-Khodor ◽  
Talib M. Albayati

The strict new regulations to reduce the sulfur content of fuel require new economical and efficient ways to remove the sulfur from the organic sulfur components. In the current work, sulfur was removed from the actual crude oil containing 2.5 wt.% from southern Iraq, specifically the Halfaya Oil Field was studied using adsorption desulfurization with activated carbon (AC). The effects of different operating conditions, including the dose of AC (0.2-1.0 gm), time (15–120 min) and temperature (30–50°C) were investigated. The best operating conditions were obtained as 0.8 gm AC, 90 minutes and 50℃, respectively. Langmuir, Freundlich and Temkin isotherm models were implemented. The steady data were best denoted via Temkin models with correlation coefficient (R2= 0.974). The kinetics sulfur components on activated carbon were examined by using pseudo-first order, pseudo-second order kinetics models and Intra-Particle diffusion. The adsorption process can be well described by pseudo-first order adsorption kinetic model with correlation coefficient (R2 = 0.9552). Thermodynamic parameters, which include Gibbs Free Energy (ΔGo), Enthalpy (ΔHo) and Entropy (ΔSo), were determined in the present research and showed that the adsorption of sulfur components on activated carbon is spontaneous, endothermic and increases the randomness of the sulfur compounds on the surface of the adsorbent. The content of sulfur in the treated crude oil was reduced from 2.5% to 1.8% corresponding to a desulfurization efficiency of 28%.


2020 ◽  
Vol 10 (6) ◽  
pp. 849-859
Author(s):  
Radwa A. El-Salamony ◽  
Abeer A. Emam ◽  
Nagwa A. Badawy ◽  
Sara F. El-Morsi

Objective: ZnO nanoparticles were synthesized using wet impregnation method, and activated carbon from rice straw (RS) prepared through chemical route. Methods: The nano-composites ZnO-AC series were prepared with different ZnO:AC ratio of 10, 20, 50, and 70% to optimize the zinc oxide nanoparticles used. The obtained composites were characterized by FE-SEM, XRD, SBET, and optical techniques then used for the photo-degradation of Malachite green dye (MG) under visible light. Results: It was found that 10ZnO-AC exhibited excellent visible light photo-catalytic performance. The ·OH radicals’ formation is matching with photo-activity of the prepared composites. The photo-degradation efficiency of MG increased from 63% to 93%, when the 10ZnO-AC photocatalyst amount was increased from 0.5 to 6 g/L. Conclusion: The GC-MS technique was used to analyze the intermediates formed; up to 15 kinds of chemicals were identified as the degradation products.


2020 ◽  
Vol 1000 ◽  
pp. 257-264
Author(s):  
Bambang Heru Susanto ◽  
Joshua Raymond Valentino Siallagan

Bio-Jet could be produced by the synthesis of vegetable oil through the hydrodeoxygenation, decarboxylation, decarbonization, and catalytic cracking process. Physical characteristics, activities, and selectivity of the catalyst used will determine the rate, conversion, and yield of the reaction that being carried out. This study aims to compare and obtain the best characteristics of NiMoP/γ-Al2O3 catalysts synthesized using two types of preparation, impregnation and microwave polyol methods, which will be used for bio-jet production. The impregnation method takes more than 24 hours for catalyst preparation, while microwave polyols that use microwaves can synthesize catalysts faster. Both catalysts have almost the same loading on the weight of the catalyst, which in the microwave polyol method has a more dispersed promotor and active site, although the crystallinity level is deficient and tends to be amorphous compared to the impregnation method with high crystallinity. In bio-jet synthesis reaction with operating conditions of 5% catalyst loading by comparison to Coconut Oil, 400°C, and 15 bar, the conversion, yield, and selectivity of catalyst impregnation were 91.705%, 47.639%, and 84.511%, while microwave polyol catalysts were 90.296%, 42.752%, and 82.517%, respectively. In conclusion, microwave polyol provides a more effective and efficient preparation method.


Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 337
Author(s):  
Sara Mesa Medina ◽  
Ana Rey ◽  
Carlos Durán-Valle ◽  
Ana Bahamonde ◽  
Marisol Faraldos

Two commercial activated carbon were functionalized with nitric acid, sulfuric acid, and ethylenediamine to induce the modification of their surface functional groups and facilitate the stability of corresponding AC-supported iron catalysts (Fe/AC-f). Synthetized Fe/AC-f catalysts were characterized to determine bulk and surface composition (elemental analysis, emission spectroscopy, XPS), textural (N2 isotherms), and structural characteristics (XRD). All the Fe/AC-f catalysts were evaluated in the degradation of phenol in ultrapure water matrix by catalytic wet peroxide oxidation (CWPO). Complete pollutant removal at short reaction times (30–60 min) and high TOC reduction (XTOC = 80 % at ≤ 120 min) were always achieved at the conditions tested (500 mg·L−1 catalyst loading, 100 mg·L−1 phenol concentration, stoichiometric H2O2 dose, pH 3, 50 °C and 200 rpm), improving the results found with bare activated carbon supports. The lability of the interactions of iron with functionalized carbon support jeopardizes the stability of some catalysts. This fact could be associated to modifications of the induced surface chemistry after functionalization as a consequence of the iron immobilization procedure. The reusability was demonstrated by four consecutive CWPO cycles where the activity decreased from 1st to 3rd, to become recovered in the 4th run. Fe/AC-f catalysts were applied to treat two real water matrices: the effluent of a wastewater treatment plant with a membrane biological reactor (WWTP-MBR) and a landfill leachate, opening the opportunity to extend the use of these Fe/AC-f catalysts for complex wastewater matrices remediation. The degradation of phenol spiked WWTP-MBR effluent by CWPO using Fe/AC-f catalysts revealed pH of the reaction medium as a critical parameter to obtain complete elimination of the pollutant, only reached at pH 3. On the contrary, significant TOC removal, naturally found in complex landfill leachate, was obtained at natural pH 9 and half stoichiometric H2O2 dose. This highlights the importance of the water matrix in the optimization of the CWPO operating conditions.


Author(s):  
Eman Hashim Khader ◽  
Thamer Jassim Mohammed ◽  
Nourollah Mirghaffari ◽  
Ali Dawood Salman ◽  
Tatjána Juzsakova ◽  
...  

AbstractThis paper studied the adsorption of chemical oxygen demand (COD), oil and turbidity of the produced water (PW) which accompanies the production and reconnaissance of oil after treating utilizing powdered activated carbon (PAC), clinoptilolite natural zeolite (CNZ) and synthetic zeolite type X (XSZ). Moreover, the paper deals with the comparison of pollutant removal over different adsorbents. Adsorption was executed in a batch adsorption system. The effects of adsorbent dosage, time, pH, oil concentration and temperature were studied in order to find the best operating conditions. The adsorption isotherm models of Langmuir, Freundlich and Temkin were investigated. Using pseudo-first-order and pseudo-second-order kinetic models, the kinetics of oil sorption and the shift in COD content on PAC and CNZ were investigated. At a PAC adsorbent dose of 0.25 g/100 mL, maximum oil removal efficiencies (99.57, 95.87 and 99.84 percent), COD and total petroleum hydrocarbon (TPH) were identified. Moreover, when zeolite X was used at a concentration of 0.25 g/100 mL, the highest turbidity removal efficiency (99.97%) was achieved. It is not dissimilar to what you would get with PAC (99.65 percent). In comparison with zeolites, the findings showed that adsorption over PAC is the most powerful method for removing organic contaminants from PW. In addition, recycling of the consumed adsorbents was carried out in this study to see whether the adsorbents could be reused. Chemical and thermal treatment will effectively regenerate and reuse powdered activated carbon and zeolites that have been eaten. Graphic abstract


2011 ◽  
Vol 65 (9) ◽  
pp. 1423-1426 ◽  
Author(s):  
José Miguel González-Domínguez ◽  
Carmen Fernández-González ◽  
María Alexandre-Franco ◽  
Alejandro Ansón-Casaos ◽  
Vicente Gómez-Serrano

2015 ◽  
Vol 1107 ◽  
pp. 341-346
Author(s):  
Wan Nazwanie Wan Abdullah ◽  
Rusmidah Ali ◽  
Wan Azelee Wan Abu Bakar

Due to the low specifications for sulfur content in diesel, a lot of research work are been conducted to develop alternative method for desulfurization. Catalytic oxidative desulfurization (Cat-ODS) has been found to be an alternative method to replace a conventional method which is hydrodesulfurization.New catalyst formulation using tert-butyl hydroperoxide polymolybdate based catalyst system was investigated in this research utilizing tert-butyl hydroperoxide (TBHP) as oxidant and dimethylformamide (DMF) as solvent for extraction. A series of polymolybdate supported alumina catalysts were prepared using wet impregnation method, ageing at ambient room temperature for 24 hours and followed by calcination process. A commercial diesel with 440 ppmw of total sulfur was employed to evaluate the elimination of sulfur compounds. Besides, the percentage of sulfur removal was measured by gas chromatography-flame photometric detector (GC-FPD). The sulfur content in commercial diesel was successfully reduced from 440 ppmw to 35 ppmw under mild condition followed by solvent extraction. From catalytic testing, Mo-Al2O3 calcined at 500°C was revealed as the most potential catalyst which gave 92% of sulfur removal.


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