Chemistry and Technology of Fuels and Oils最新文献

The article reviews the most common analytical methods for calculating the parameters of minimum reflux condition during fractionation of multicomponent mixtures, taking account of the specified separation products quality requirements. A calculation procedure that makes it possible to simplify determination of minimum reflux or vapor ratios as well as of distillate or residue compositions under minimum reflux condition compared to the known methods is proposed and described.

Shale gas is an extremely important unconventional oil and gas resource, and its efficient development can effectively alleviate the current tense energy situation. However, shale gas reservoirs often have extremely poor permeability, and reservoir transformation has become a key technology for achieving their efficient development. However, the commonly used hydraulic fracturing technology is difficult to achieve its target production capacity, and other engineering technologies related to reservoir transformation urgently need to be proposed and attempted. The synergistic operation of oxidation dissolution and acid fracturing may provide new ideas for the effective transformation of shale reservoirs. To this end, a comparative analysis was conducted on the synergistic effects of oxidation dissolution and acid fracturing operations in improving shale gas production capacity. The research results indicate that the dissolution effect of oxidants is more effective than acid solution in the transformation process of shale reservoirs. The use of acid only widens the crack width from the initial 4.4 mm to the final 5.1 mm. However, the use of oxidants will result in the final width of hydraulic fractures reaching 8.3 mm. Meanwhile, the effects of acid concentration and oxidant concentration on hydraulic fracture conductivity and shale gas production capacity were investigated. The results indicate that increasing the acid concentration below the low concentration range can significantly enhance the fracture conductivity, thereby promoting the production capacity of shale gas. However, within a higher concentration range, its effect on shale gas production is significantly limited. It is recommended to set the acid concentration design value at 0.5 wt% during the acidizing and fracturing reservoir transformation process of the shale gas reservoir in Changning block. In addition, an increase in the concentration of oxidants can widen the width of fractures and increase permeability, thereby promoting the migration and extraction of shale gas. To avoid the increase in development costs caused by high oxidant concentration in the working fluid, it is recommended to design the oxidant concentration at 3 wt%.

This study investigates the catalytic effects of Nickel-ligated catalysts derived from tall oil (NiTO) and sunflower oil (NiSFO) on the oxidation of heavy oil. Thermogravimetric (TG) analysis were employed to assess the thermal behavior and kinetics of heavy oil degradation. The Friedman isoconversional method provided the activation energies (Ea ), which were then used to derive thermodynamic parameters including changes in enthalpy (ΔH), entropy (ΔS), and Gibbs free energy (ΔG). The TG analysis revealed that both NiTO and NiSFO influence the degradation kinetics of heavy oil. Moreover, NiTO exhibited a consistent catalytic effect across a wide range of conversions, lowering the onset temperature of degradation and promoting faster degradation rates, which suggests a rapid breakdown at lower temperatures. Conversely, NiSFO demonstrated a substantial decrease in activation energy at mid-range conversions, indicating a highly efficient catalysis during these stages. In addition, thermodynamic analysis indicated that both catalysts alter the energetic profile of the reaction. Notably, NiSFO reduced ΔG significantly at lower conversions, enhancing the spontaneity of the reaction, while NiTO was associated with lower ΔG values across most conversions, implying a more favorable reaction throughout the process. The findings suggest that the choice of catalyst can be tailored based on the desired conversion range and reaction spontaneity in industrial heavy oil processing. These insights could be crucial for optimizing thermal treatments in heavy oil upgrading, offering potential improvements in the efficiency of in-situ combustion and enhanced oil recovery technologies.

As a non-invasive tool, ultrasound waves can be applied to probe gaseous content of the drilling fluid in offshore oil-drilling operations. The approach is believed to improve sensitivity and accuracy of a gas-kick detection system. In this research, four types of bubble flow are designed to simulate undeveloped gas kicks, and their effects on changes of ultrasound waves are investigated. The bubbles are found to have changed power distribution of the sound waves that have been reflected by the bubbles and received by side sensors. The pattern of power spectrum changes around the master frequency is found to be closely related to the type of bubble flow. Such changes are grouped on the basis of cluster analysis, and it is found that bubble strings and bubble groups would produce substantially different effects and that bubble mergences would largely alter spectral property of the sound waves. By establishing relationship between power-change pattern of sound waves and the behavior of a bubble flow, the research is intended to seek a more predictive way of recognizing early-stage gas kicks for offshore oil-drilling practices.

Utilizing emulsion polymerization, a microcapsule breaker with a polystyrene-polyacrylamide core-shell structure was synthesized. Ammonium persulfate served as the breaker, polystyrene as the shell, and polyacrylamide as the drug-carrying agent. The results demonstrated that the synthesized microencapsulated gel-breaker exhibited a uniform spherical shape, superior water dispersion, and enhanced thermal stability. Conductivity tests indicated that the core-shell structure of the microcapsules effectively regulated the release of ammonium persulfate as a gel-breaking agent, resulting in delayed polymer gel-breaking.

The feasibility of use of natural nanomaterials, namely, natural aluminosilicate (halloysite) nanotubes and nanocellulose, as modifying additives to commercial polyurethane foam to vary fire resistance and mechanical properties was studied. Series of composite polyurethane foams containing various weight proportions of the modifying additives were obtained via in situ polymerization. The effect of the additives on the polyurethane foam structure, compressibility, and fire resistance was studied. It was observed that introduction of additives into polyurethane foam leads to change of the average pore size and reduction of foams compressibility. However, once the the maximum rigidity of the foam composites was reached, further increase of additive content causes regression of this characteristic. It was also confirmed that increasing additive content positively affects the fire resistance of the produced composites.

A study was carried out on the quality of the cobalt carbonate raw material and heat treatment conditions on the activity of Co-Mo and Ni-Mo hydrotreating catalysts for a mixed diesel fraction. The relevant properties of the impregnation solution are the purity of the cobalt carbonate starting material and the synthesis temperature. A Raman spectroscopic method was proposed for monitoring the cobalt carbonate quality. Heat treatment of the catalyst was found to affect its activity. The optimal ultimate calcination temperatures for the Co-Mo and Ni-Mo catalysts were found to be very different.

Composting is an effective and cost-efficient engineering technique used to treat agricultural waste. It involves the conversion of organic materials into stable compounds and the rapid degradation of organic matter through microorganisms found in feces. The resulting high-quality fertilizer can improve soil physical, chemical, and biological properties. However, the excessive use of heavy metals in livestock breeding can restrict the use of livestock manure for composting. Long-term application of compost products containing heavy metals can cause irreversible damage to farmland soil environments. This paper summarizes several important factors that affect the detoxification of heavy metals in composting and discusses the passivation effect of typical heavy metal passivators. The detoxification mechanism of heavy metals in compost is summarized from two perspectives: the humification effect of heavy metals and the environmental interface effects of microorganisms. This paper provides a foundation for improving the agronomic use value of avian manure aerobic composting products and for studying heavy metal passivation in compost. The application of aerobic composting in the remediation of petroleum-contaminated soil exhibits a dual impact, primarily focusing on the synergistic effects on petroleum hydrocarbon degradation and soil improvement. Such research endeavors are poised to offer innovative solutions towards achieving comprehensive restoration of petroleum-contaminated soils.

A complete analysis of the existing methods of synthesis of polyhydroxylated fullerenes using direct chemical interaction, as well as alternative methods of creation has been carried out in order to identify the optimal methods of obtaining, for their implementation in various technological and biomedical fields. The scientific literature on this field of research is summarized and classified, and a comparative assessment of the efficiency and feasibility of practical implementation of the developed synthesis methods is given on the basis of a comprehensive review of literature and patent documents.

Porosity has an important influence on the elastic properties of tight sandstone. Using acoustic models to study the matrix mineral modulus of tight sandstone reservoirs can provide an important reference for tight sandstone reservoir evaluation. In this paper, taking tight sandstone as an example, starting from the microscopic pore scale and considering the heterogeneity of the rock skeleton, the effect of the effective stress coefficient of porosity (n) on the elastic properties of tight sandstone was discussed. In addition, the acoustic model was used to construct the calculation method of the matrix mineral shear modulus. The research results showed that the porosity disturbance model can better describe the change law of the elastic properties of the tight sandstone. As the value of n decreases from 1 to 0, the bulk modulus (K_φ) of the unencapsulated rock gradually decreases. In the process of increasing from n=0 to n=4, the rock Kud has a slight increase trend. The fluid pressure does not produce a reverse stress effect on the movement of the rock pore boundary, that is, the fluid pressure does not have any effect on the change of the rock porosity. When n>0, the pore fluid pressure will affect the movement of the rock pore boundary to a certain extent. When the porosity disturbance is not considered, the K_φ value of the formation rock will be overestimated. The Ko of tight sandstone can be obtained using Gassmann fluid substitution equation. The calculation results of modulus parameters accord with the internal mineral composition and structural characteristics of tight sandstone, which shows the effectiveness of the method.