Chemistry and Technology of Fuels and Oils最新文献

The thermal and hydrothermal processing of polyvinyl chloride waste was studied. The liquid product in the hydrothermal processing of polyvinyl chloride with 10% aqueous NaOH contains the least amount of chloroaromatic hydrocarbons in comparison with thermal processing without water. A scheme was proposed for two-step processing of polyvinyl chloride, in which the first step entails hydrothermal or thermal treatment followed by hydrodechlorination of the resultant liquid product on sulfide catalysts. Industrial sulfide and nanoheterogeneous NiWS and NiMoS catalysts synthesized by the authors were studied in the hydrodechlorination of the chlorine-containing mixtures. The greatest activity in the hydrodechlorination process was found for an unsupported NiWS catalyst synthesized ex situ.

A study was carried out on benzyl alkoxycarbonyl methyl disulfides as multifunctional additives to lubricating oils. Results are given for testing the anticorrosion, anti-wear, anti-microbial action of previously synthesized benzyl alkoxycarbonyl methyl disulfides containing several functional groups. Efficiency was demonstrated for a series of benzyl alkoxycarbonyl methyl disulfides. Depending on their composition and structure, these disulfides improve the anticorrosion, anti-wear, and antimicrobial properties of oils. The antimicrobial properties of these compounds were studied as components of M-11 oil. The synthesized compounds in concentration 0.5-1.5 mass % enhance the resistance of mineral oil to biological damage and also display antimicrobial and antifungal activity. These compounds are more efficient than sodium pentachlorophenolate, which is a commonly used biocide. Testing in a four-ball friction machine indicates that these compounds possess anti-wear properties. Our derivatograph data on the thermal stability of these additives are in accord with the results of thermoanalytical testing of commercial additives.

A corrosion inhibitor composite was developed for carbon dioxide corrosion and it was adapted to the requirements of dosage, protective capacity, temperature characteristics, and compatibility with other reagents. The development process and the main requirements, observance of which was monitored, are described stage-by-stage. The outcome of the conducted research was two grades of a carbon dioxide corrosion inhibitor based on an imidazoline derivative. The difference between the developed composites lies in the solvent type and, correspondingly, in the temperature characteristics (flash and dew points). The influence of the amount of the active base on the effectiveness of the composite was evaluated and the optimum content of the components in the corrosion inhibitor was found. The importance of flash and dew points for corrosion inhibitors is underscored and a way of controlling these composite indicators is proposed.

Carotid stenosis constitutes a common vascular disease that significantly affects cerebral blood flow and thus is associated with patients' cognitive functions. Carotid revascularization techniques [carotid endarterectomy (CEA) and carotid artery stenting (CAS)] may benefit cognition, though there are opposing findings, reporting an apparent decrement in cognitive function, no effect, or an apparent improvement after revascularization. A great number of studies are trying to evaluate the effect of carotid revascularization (CEA, CAS) on patients' cognitive functions, as well as on their psychological condition and quality of life through a baseline and follow-up neuropsychological examination. Recent reviews refer only to the narrow limits of cognitive deficits that may be attributed to carotid stenosis, rather than elucidating the outfit of all aspects of mental and cognitive correlations. Most of those findings depict controversy in current literature as far as the neuropsychological effects of carotid revascularization techniques are concerned, while clinical entities of "vascular dementia" and "vascular depression", as well as intercurrent vascular risk factors are also addressed. This might be taken into consideration, when determining the optimal therapeutic strategy for tackling carotid artery occlusive disease, while best practice clinical decisions should be still focused on stroke prevention and symptoms alleviation, until further research on the field of neuroangiology presents undisputable conclusions regarding the underlying effects of revascularization on mood and cognition. Τhe neurovascular interface, as far as mental and neurocognitive impact of carotid stenosis is concerned, also, comprises, the conceptual pathophysiological entity of "atheroinflammation", underscoring the association of vascular lesions with cognitive impairment, major depressive disorder and bipolar disorder. Chronic recurrent ischemia and chronic low perfusion are also addressed from neurocognitive aspect, regarding therapeutic strategies that might be preferred so as to reduce the burden of chronic cerebrovascular disease in both symptomatic and asymptomatic patients, given the fact that inflammatory processes of vascular complexion underlie both neuroinflammation and atherosclerosis, affecting cerebral perfusion as well as cortical blood flow.

Aiming at the problem that the water intrusion control factors of multi-stage fracturing horizontal wells in tight gas reservoirs in edge and bottom water are not clear, the linear supply boundary is used to characterize the water intrusion characteristics and derive the mathematical characterization formula, considering the stress sensitivity and diffusion mechanisms of tight gas, and the water intrusion flow model of multi-stage fracturing horizontal well in tight gas reservoirs in edge and bottom water is established, and the bottom pressure and its derivative curves are obtained by Laplace and perturbation transformation. Furthermore, the influence of water intrusion strength, matrix-fracture channeling capacity, storage capacity coefficient, fracture segment spacing, fracture conductivity and other factors on the degree of water intrusion and water exposure time were analyzed. By fitting the well test data of the established model, the water intrusion intensity parameters can be obtained, and the water intrusion control of gas wells can be guided according to this parameter. The data analysis of two typical wells in the western oilfield was carried out by applying the established model, and the analysis results were well matched with the actual production, which verified the reliability of the model, and according to the analysis results, the treatment measures of the two wells were proposed, and the two wells obtained good production results.

The chemical paraffin removal agent QLJ-1 was developed by analyzing the composition of crude oil, the wax content and the point of paraffin removal in the wellbore of an oilfield in northwest China. The orthogonal test was used to determine the formula as follows: mixed organic solvent (70% aromatics, alkane volume ratio of 2:2:1) + mixed surfactant (7% Tween-80, AEO-9, fatty acid salt mass ratio of 1:2:1) +23% pure water. The results of kinetics and emulsion stability study show that the saturated wax dissolution amount of QLJ-1 is 1.62 g, the wax dissolution rate is 0.0263 g/min, the wax dissolution equilibrium time is about 1h, and the emulsion stability time is 6 d. The wax dissolving effect of QLJ-1 is better than that of the current paraffin remover. The research results of this paper can provide technical support for improving the chemical paraffin removal process in an oilfield in Northwest China.

In order to understand the problem of sediment sources in the Xujiahe Formation of the Central Sichuan Uplift, high-density two-dimensional seismic data was used, and LCS2 (the second section of the Xujiahe Formation) was taken as the research object. Combined with logging interpretation results, typical seismic facies were identified within the sequence, including clinoform seismic facies, progradational reflection seismic facies, and incised valley seismic facies. The progradational reflection seismic facies can be divided into two types: S-shaped and oblique progradational reflection facies. The oblique progradational reflection seismic facies representing the rapid filling environment of sediments are mainly distributed in the southeast of the study area, while the northwest mainly develops relatively low-energy sedimentary mechanisms of S-shaped seismic facies. The incised valley seismic facies are mainly distributed in the eastern and southeastern parts of the work area. On the plane, the incised valley seismic facies have a trend of gradually widening and shallowing towards the northwest direction. In addition, the distribution of sedimentary facies was analyzed using seismic attributes. The southeastern and central parts of the study area are mainly composed of proximal sand-rich braided river alluvial plains, while the northwestern part is mainly composed of distal mud-rich braided river alluvial plains. The distribution of sedimentary facies generally shows a southwest to northeast distribution. From southeast to northwest, the sedimentary facies show a clear trend of changing from sand-rich to mud-rich. Based on the comprehensive distribution characteristics of seismic and sedimentary facies, it is believed that the river in the Central Sichuan Uplift basically enter the region from the south or southeast, and transport sediments from southeast to northwest. Based on the above evidence, it is inferred that the sedimentary material of the Xujiahe Formation in the Central Sichuan Uplift mainly comes from the «Qianzhong Ancient Uplift» or «Fanjing Mountain Ancient Land» on the southern and southeastern of the Sichuan Basin.

Geological carbon storage is considered to be an effective measure to mitigate climate crisis. The method in which CO₂ is stored depends on its phase state and the depth at which it is injected. In this study, the fault-reservoir system is constructed to elucidate the fault leakage behaviors and CO₂ migration in different geological storage environments. Whether CO₂ is buoyant or sinking depends on the fluid density difference between CO₂ and H₂O. When carbon dioxide is injected into deep saline aquifer, CO₂ would preferentially migrate upward along the fault plane due to CO₂ buoyancy forces, and CO₂ plume accumulates beneath the caprock and floats at the top of the reservoir eventually. For CO₂ storage in deep ocean reservoir and volcanic basalt, no upward migration of CO₂ plume is observed during carbon storage. Fault plane is the preferential pathway for carbon downward transportation during ocean-based CO₂ storage, providing a virtually unlimited environment. Compared with deep ocean storage, the much shorter sinking times makes volcanic basalt for carbon storage safer and more effective. It is illustrated that the fluid density difference between CO₂ and H₂O is the decisive factor in determining CO₂ sinking velocity. This investigation of searching CO₂ sinking reservoirs provides a promising alterative reference for remove and storage large volumes of the greenhouse gas.

Calcareous interbeds control the migration of oil and water in marine strata. However, in China, the origins of such calcareous interbeds have not been investigated in detail. In this paper, we present a study of calcareous interbeds in marine strata of the Zhujiang Formation in the Wenchang Oil Field, which is located in the southeast of Hainan Province, China. The lithological characteristics, types and features of diagenesis, and formation of the calcareous interbeds were investigated using core, thin-section, scanning electron microscopy, and cathodoluminescence observations, and stable carbon and oxygen isotope data. The calcareous interbeds consist of mixed sediments, which are dominated by bioclastic limestones containing terrigenous clasts, along with subordinate calcareous sandstone. The interbeds are densely cemented. The bioclasts are dominantly brachiopods, pleopods, and foraminifera, with minor amounts of echinodermata, bivalves, red algae, ostracods, and bryozoa. Diagenesis involved calcitic cementation, associated with relatively weak compaction. Carbon and oxygen isotopic data indicate the pore water that formed the carbonate cement was mostly sourced from seawater and minor amounts of meteoric water. The degree of carbonate cementation was significantly related to the bioclast content. On the basis of our study, a genetic model for the macroscopic and microscopic formation of calcareous interbeds is proposed.

It is common knowledge that in-situ combustion is highly promising method for improving heavy oil recovery. The present research explores the effects of Cobalt-ligated catalysts derived from sunflower oil (CoSFO) and tall oil (CoTO) on heavy oil oxidation, aiming to enhance in-situ combustion process. Through differential scanning calorimetry (DSC) we assessed the oxidation kinetics of heavy oil in the presence and absence of these catalysts. Our findings indicate that both CoSFO and CoTO significantly improve the oxidation process, particularly in the high-temperature oxidation (HTO) phase crucial for combustion front stabilization. Notably, CoTO demonstrated superior efficacy in reducing oxidation times across all conversion levels, suggesting its potential to optimize the efficiency of EOR techniques. This research highlights the promise of Cobalt-ligated catalysts in advancing heavy oil recovery and suggests directions for future studies to further investigate their industrial applications.