Applied Petrochemical Research最新文献

A mathematical model was developed for a diffusion–reaction process in a spherical catalyst pellet contained in a heterogeneous packed bed reactor. The model developed was solved to predict the effectiveness factor and also to perform sensitivity analysis for steam reforming of methanol on Cu/ZnO/Al₂O₃ catalyst a source of hydrogen fuel. The method of orthogonal collocation was used to solve the resulting differential equation. At temperature below 473?K the effect on intra-particle diffusion limitation is reduced to the minimum indicated by the effectiveness factor being almost equal to one but as the temperature increases above 473?K there is considerable increase in the diffusion limitation effect. The effects of thermal conductivity, diffusion coefficient, catalyst size and surface temperature on effectiveness factor for the reaction process were also considered. Result indicates that catalyst size of (1.623,, times ,,10^{ - 4})?m eliminates the effect of intra-particle diffusion resistance in the pellet. The variation of effectiveness factor with Thiele modulus, showing the asymptotic values, using power law and Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetics, was predicted. The two reaction kinetics had almost the same magnitude of effectiveness factor at different Thiele modulus which indicates that they can adequately predict the reaction process.

The paper reports the adsorption studies of asphaltenes of Iran’s heavy crude oil on some natural and synthetic alumino-silicates. Asphaltenes were precipitated using n-heptane. Toluene was used as a precipitating solvent of asphaltenes and several zeolites including 4A, ZSM-5, Clinoptilolite, and La-modified bentonite (Phoslock) as adsorbents. FTIR analysis indicated the asphaltenes which comprise a complex of aromatic, aliphatic, and polar compounds. The pore size and outer surface area of the adsorbents were determined by BET method and the following order was found between outer surface areas: ZSM-5 (238.27?m²?g^?1)?>?Clinoptilolite (28.75?m²?g^?1)?>?Phoslocks (27.92?m²?g^?1)?>?zeolite 4A (21.11?m²?g^?1)?>?Zeolite 13X (317.24?m²?g^?1). Besides, the adsorption isotherms were investigated with the conventional isotherm models and it was indicated that the Langmuir isotherm fitted the experimental data. Zeolite 13X with the highest specific surface area and pore size exhibited the maximum adsorption capacity, indicating that there is a direct relationship between surface area and adsorption capacity. However, it seems that the pore size effect is more prominent because of the large size of asphaltene’s molecules.

The study of a light cycle oil (LCO) upgrading alternative involving hydrotreating and hydrocracking/transalkylation procedures for obtaining a benzene, toluene and xylene (BTX) enriched fraction is presented. The research work was focused on the effect of the experimental conditions on the hydrocracking of an hydrotreated light cycle oil (HDT LCO) in order to produce the highest amounts of BTX, when the catalysts consisted of a mixture (50/50 in weight) of nickel–molybdenum on alumina (NiMo/Al₂O₃) and ZSM-5 materials (NiMo/ZSM-5 (50)). It was found that 7.4?MPa, up to 375?°C, LHSV of 1.2?h^?1 and a H₂/Oil value of 442 m³/m³ were the optimal experimental conditions for producing an enriched BTX fraction (31%). In order to facilitate the analysis, the study was carried out considering four types of hydrocarbons as lumps for the feed and HCK products: light hydrocarbons (LHC) composed by C4–C7 non-aromatic compounds, BTX, middle hydrocarbons (MHC) consisting of C7–C10 paraffins and isoparaffins, alkylbenzenes, tetralin and naphthalene derivatives and a small amount of high molecular weight hydrocarbons (HHC). Based on this description, HDT LCO used as feedstock for the hydrocracking (HCK) procedure, presents a 99% of a MHC fraction. The HCK conversion, BTX selectivity and yields were obtained from the chromatographic analysis of the products. A simple kinetic model considering only the MHC conversion was carried out. The obtained activation energy confirmed the endothermic nature of the HCK process. The activity decay of the catalytic mixture was also studied by varying the time on stream.

The use of zeolites in Co-catalysts of Fischer–Tropsch synthesis (FTS) results in cooperative effect in the form of sudden increase of the zeolite activity in catalysing secondary transformations of FTS-generated hydrocarbons at unusually low temperatures in the range of 170–260?°C. In addition, hydrophobic zeolites in H-form allow changing the hydrophobicity of the pore walls and influence capillary condensation phenomena for intermediate species. The most unexpected effect of Co and hydrophobic zeolites is the improvement of degradation behaviour of the catalysts due to involvement of FTS-generated water into formation of additional Bronsted centres thus preventing undesirable oxidation of heat-conductive metal additives and other water-induced degradation processes. In addition, the stability of catalyst behaviour and its lifetime increase.

Combustion of fossil fuels gives rise to sulfur oxides, which are harmful to the environment. Adsorptive desulfurization (ADS) of diesel was conducted using sewage sludge activated with H₂O₂ as the oxidizing agent. A full 2² central composite response surface design was employed to determine optimum conditions for the production of activated sewage sludge (ASS). The adsorbent (ASS) was characterized using SEM, EDX and FTIR and the results of the analysis showed that it has the capacity to desulfurize diesel significantly. The ASS was subsequently used to conduct batch ADS of diesel with a view to investigate the kinetics, equilibrium and thermodynamics of the process. The optimum conditions established for the production of ASS using H₂O₂ as the oxidizing agent were: temperature 400?°C and holding time 60?min. The Elovich model gave the best fit to the kinetic data of the ADS of diesel using ASS, while the equilibrium study showed that the Freundlich isotherm fitted the data at 35?°C better than Temkin and Langmuir isotherms. The positive values of the free energy and enthalpy changes revealed that the process was non-spontaneous and endothermic, respectively, while the negative entropy change is evidence of decrease in randomness of the adsorbed species. 33% desulfurization was achieved in 100?min during ADS of diesel showing that the adsorbent developed by activating SS with H₂O₂ was very good and effective. Thus, ASS can be used to gain more insight into kinetics, equilibrium and thermodynamics of the ADS of middle-distillate petroleum fractions.

DRIFTS experiments such as CO adsorption, CO-TPSR and CO+H₂ were designated to study the effect of Fe promoter on the key steps of C₂ oxygenates formation from syngas. The CO adsorption results demonstrated that Fe weakened CO adsorption and especially the bridging adsorption. It was found in CO-TPSR experiments that the catalyst with lower Fe loading is more easily dissociated while the ones with higher Fe loading own stronger hydrogenation activity. Moreover, it was observed by CO+H₂ experiments that Fe plays a role in stabilizing the lineally adsorbed CO species and decreasing the CO desorption rate. The catalytic performance results indicated that when Fe content is 4wt.?%, the selectivity of total C₂ oxygenates is the highest, which was in accordance with the DRIFTS results.

The presented article shows the studies of hydrocracking process of fuel oil with the purpose of obtaining light oil products (benzene and diesel fractions) from heavy oil residues (fuel oil), thus, deepening the refining of oil. The hydrocracking of fuel oil was conducted in the presence of halloysite modified with transition metals (Mo, Ni). Toward this end, halloysite was modified by two different methods—absorption and ion-exchange methods. It was shown that, at optimal conditions (430?°C, 4?MPa), 46.6% (wt.), 53.0% (wt.), 63.0% (wt.) and 83.0% (wt.) light oil products are obtained by the hydrocracking process of fuel oil carried out without catalyst, in the presence of unmodified halloysite, halloysite modified by absorption method and halloysite modified by ion-exchange method, respectively. The obtained benzene and diesel fractions after hydrorefining process can be added to fuels as components.

Light cycle oil (LCO) is an inexpensive feedstock for the production of high-added-commercial-value-mono-aromatic compounds such as benzene, toluene and xylenes (BTX). To extend the knowledge on the processing of LCO for BTX production, the hydrocracking reaction was studied using a commercial NiMo/Al₂O₃ catalyst, ZSM-5 zeolite and their mechanical mixtures (20/80, 30/70 and 50/50) for processing tetralin as model feedstock in a bench-scale-trickle-bed reactor at 450–500?°C, 3.9–5.9?MPa, 1.3 1/h and H₂/feed volume ratio of 168–267?m³/m³. Accessible, well-dispersed and strong Br?nsted acid sites eased the hydrocracking of tetralin to BTX and the metallic hydrogenation functions from nickel–molybdenum catalysts were also required to minimize deactivation. To achieve suitable tetralin conversions (86–95?wt%), high BTX selectivity in the liquid phase (44–70?wt%) and suitable catalytic activities for coke precursor hydrogenation (to reduce deactivation), NiMo/Al₂O₃//ZSM-5 mixtures (50–80 ZSM-5) were employed, which probed to be effective.

Herein, a study of phosphate synthesis reactions with triethyl phosphate, phosphorous pentoxide and mixed alcohols is described. The synthesized phosphates are used as gelling agents in LPG fracturing fluids. By this study, a phosphate product with good performance has been obtain by screening different combination of alcohols and various reaction conditions including the ratios of reactants, reaction temperatures and reaction times. The LPG fracturing fluid prepared with the phosphate product we optimized maintains a viscosity of 200?mPa?s for 1.5?h at 90?°C and 170?s^?1 shear rate.

A Schiff base containing the 1,2,4-triazole moiety was synthesized and added to polystyrene at low concentration for a homogenous blend. The polystyrene film was irradiated with ultraviolet light and the surface morphology was analyzed. Micrographs of the polystyrene/Schiff base blend after irradiation indicated the fabrication of a terrestrial crack-like material. This was ascribed to the presence of the Schiff base, relatively long irradiation time, and photostability induced by the base. After irradiation, the blank polystyrene film formed a cotton-like fibrous material.