Petroleum Chemistry最新文献

This review presents the current understanding of the effects of the physicochemical properties of molecular sieve catalysts on their deactivation in methanol-to-hydrocarbons conversion. The catalysts are classified on the basis of the composition of the so-called hydrocarbon pool and the catalyst deactivation rate during methanol conversion. For each group of catalysts, the correlations of their physicochemical properties with their catalytic performance, coke formation, and deactivation behaviors are discussed.

Considering the lifespan of wells and the increment of water production over time, which is associated with the increase in emulsion volumes, the need for technology able to overcome these challenges becomes paramount. In this study, the flow characteristics of a nanoparticle-stabilized water-oil emulsion were investigated for different nanoparticle concentrations and water fraction. The influence of different concentrations of silica dioxide nanoparticles on the pipeline flow behavior of emulsions was studied in a 13-m horizontal pipe with the inlet diameter of 0.0145 m. The effect of nano-silica (1, 3, and 5 wt %) on the emulsion stability, rheological type, viscosity, and pressure drop as well as on the energy consumption (for the water volume ratios of 35 and 50% v/v) was also investigated. The study showed that as the water cut increased, the viscosity of the produced oil increased proportionally to the water/oil volume ratio. Use of nanoadditives provided the viscosity reduction for two water cuts (35 and 50%). In the case of a 50% water cut, addition of 3% of nano-silica provided the most significant trend in reducing viscosity. In the case of addition of 1% nano-silica to a 35% water cut, the viscosity level decreased, and the shear-thinning behavior was observed for all the prepared emulsions. Nevertheless, the most significant amount of stable emulsion was produced at a water ratio of 35%, when a 3% nano-silica was added. The results also show that the addition of nanoparticles caused a decrease in the pressure drop, and the addition of 3% of nano-silica resulted in a highly stable emulsion and increased power consumption by a pump.

The physicochemical properties of BEA zeolites with SiO₂/Al₂O₃ ratios of about 40–50 and 200–250 synthesized in fluoride and alkaline media have been characterized, and their catalytic activity have been tested in liquid-phase disproportionation of toluene. It has been found that samples with a close SiO₂/Al₂O₃ ratio obtained by fluoride synthesis have a smaller number of acid sites. The samples with lower SiO₂/Al₂O₃ ratios exhibite a higher activity in toluene disproportionation than the samples with lower Al content, regardless of the synthesis method. The BEA zeolites that have Al atoms in the T6 positions of the framework which are more active. Synthesis in an alkaline medium promotes the localization of aluminum at the T6 position.

Based on the 5-year data on the feed oil characteristics obtained from the S Zorb unit, the outliers in the data were detected using the boxplot and LOF methods, and 536 modeling samples were obtained. Combining MIC with the Pearson correlation coefficient, six characteristics of feed oil including RON, sulfur content, olefin content, aromatic content, density, and vapor pressure were chosen as input variables for the clustering model. Two features were extracted from the six variables by the autoencoder (AE) characterized by the 6-32-2-32-6 neural network structure and PCA algorithm for clustering. Three clustering models were built using AE+K-means, PCA+K-means, and K-means. The results of evaluation showed that the optimal clustering number in these models was three, and the AE+K-means model provided the best clustering effect. According to the clustering centers and the property distribution, the dividing boundaries between three types of feed oils are obvious indicating that the AE+K-means model is available to classify feed oils from the S Zorb unit. On this basis, prediction models for the RON of refined gasoline were built for different types of feed oils to get the optimal operation conditions for the reduction of RON losses of refined gasoline in the S Zorb unit.

A representative set of crude oils from the Timan–Pechora oil-and-gas basin (OGB) (75 samples of crude oils and natural-gas condensates from 51 fields) was studied, and data on the structural-group composition of the crude oils from this field were obtained. The distributions of all the parameters are far from the normal distribution. Therefore, only methods of nonparametric statistics can be used for the data processing. Among Timan–Pechora crudes, there are samples with abnormally high content of unsaturated compounds of radiogenic nature. Their highest concentration corresponds to the irradiation dose of no less than 11 MGy. On the whole, Timan–Pechora crudes differ from those studied previously (from the West Siberian, East Siberian, Volga–Urals, and North Caucasus OGBs) primarily in the content of monoaromatic components. The Timan–Pechora crudes occupy an intermediate position between those from West Siberia and Volga–Urals, on the one hand, and from East Siberia and North Caucasus, on the other hand. As compared to crude oils of the second group, Timan–Pechora crudes have considerably higher content of aromatic compounds. In the content of bi- and polycyclic aromatic components, Timan–Pechora crudes are close to those from West Siberia and Volga–Urals. All the large tectonic structures are combined in four groups with respect to crude oil composition: (1) Varandei–Adzva zone + Khoreivei and Kos’yu-Rogovskaya depressions; (2) Izhma–Pechora syneclise + Upper Pechora depression; (3) Pechora–Kozhva aulacogene; and (4) East Timan megalithic bank.

Extractive oxidation of diesel via microwave processing using sulfuric acid and two synthesized pyridinium- or methylpyridinium-based ionic liquids has been studied as a sustainable and clean technology. The Central Composite Design (CCD) representing one of the response surface methods was applied for the experimental design, mathematical modeling, optimization, and factor-influence study, which covered the 0.75–1.75 [CH₂COOHmPy][HSO₄]/[H₂SO₄] volumetric range, 40–80°C temperature range, and 120–300 s radiation exposure time. The developed model properly fitted experimental results, with a coefficient of determination (R²) equal to 0.9832 that indicated its accuracy. The highest predicted sulfur removal (93.338%) as well as a significant removal of nitrogen and aromatic compounds was obtained for [CH₂COOHmPy][HSO₄]/[H₂SO₄] = 1.57, T = 71.7°C, and exposure time equal to 208 s. Microwave-assisted extractive oxidation demonstrated a considerable potential as the energy-saving technology, which meets the future need for producing clean fuels with low content of heteroatoms and polyaromatic hydrocarbons.

This review provides an analysis of prior research on the oxidation of organic compounds with oxygen as an oxidant in the presence of transition-metal molybdates. The reaction mechanisms suggested for the oxidation of various classes of organic substrates, methods for the synthesis and modification of molybdates, and promising industrial applications of molybdate catalysts are discussed.

This review provides an analysis of prior research on the kinetics of the trimerization of ethylene to 1-hexene over existing chromium-based catalytic systems. It discusses the known mechanisms and reaction steps for the formation of 1-hexene as well as olefin by-products. The effects of catalytic system composition, temperature, pressure, reaction time, and the presence of hydrogen on the kinetics of 1-hexene formation are also touched upon. The kinetic models of ethylene trimerization to 1-hexene known from published literature are presented.

The catalytic properties of mesoporous amorphous titanosilicate Ti–Si in acetone homocondensation at 250–350°С and mass feed space velocity of 0.5–10 h^–1 were studied. The acetone conversion was 13–52 wt %, and the selectivity with respect to mesitylene was 52–70 wt %. A kinetic model based on the experimentally developed scheme of chemical transformations was constructed; it includes 10 steps and takes into account the effect of water. The retrieval of the kinetic parameters was implemented in the form of a global optimization problem, which allowed determination of the kinetic constants, adsorption constant, activation energy, and heat of adsorption of water.

The present study investigates the effects of heat treatment temperature on the physicochemical properties of bulk granular Ni–Mo–W catalysts. A series of bulk catalysts were synthesized and characterized by X-ray diffraction analysis, low-temperature nitrogen adsorption/desorption, CHNS elemental analysis, Raman spectroscopy, and X-ray photoelectron spectroscopy. To evaluate the catalytic activity in hydrodesulfurization and hydrodenitrogenation reactions, the catalyst samples were tested in hydrotreating of vacuum gasoil. It was found that the bulk granular catalysts calcined at 400°C and lower temperatures were mainly X-ray amorphous. In the samples calcined above 400°C, a nickel molybdate phase was predominant. In these samples, the content of an active sulfide phase after sulfidation was lower than that in the samples prepared from X-ray amorphous oxide precursors. The test data showed that the catalyst calcined at 300ºC exhibited the highest activity in the hydrodesulfurization of vacuum gasoil.