Chemistry and Technology of Fuels and Oils最新文献

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.

Thermal pressurization of the trapped pore fluid is considered to be a widespread fault weakening during fluid injection in confined geological formations. Tremendous amounts of heats will be generated within the narrow shear zone during fault slip. Considering the melting of the fault gouge, the fault seal zone is adopted to construct the fluid pressurization model, thermal pressurization implemented in Comsol Multiphysics is established to illustrate the fault weaken coefficient and effective normal stress during fluid injection. The friction weakening coefficients m_T and m_F are proposed to research the performance of fault weakening during fluid injection. The results indicate that, the friction coefficients m_T and m_F both exhibit the initially decreasing and then increasing tendency, and thermal-induced fault weakening of CO₂ injection occurs earlier than that of water injection. It was found that initial pore pressure and fault sealing porosity have a negligible influence on the evolutions of friction weakening and effective normal stress. Initial normal stress and fault sealing permeability have certain obvious influences on fault weakening during CO₂ injection. Fault thickness is the primary factor influencing the friction weakening coefficient. When the fault thickness is over 1 mm, the variation of fault weakening is totally different from that when the thickness is less than 1 mm. This investigation of friction weakening during fault slip provides an effective reference for fluid injection.

Heihai Lake, a freshwater lake in the area of the East Kunlun Mountains is an accurate monitor of climate-driven hydrological and environmental changes during the past 2000 yr BP. In order to reconstruct the environment in the north Tibetan Plateau, we studied the multi-proxy records from Heihai lake sediments. Major analyses comprise mineral composition (XRD), morphology of minerals (ATEM), geochemical data (XRF), Ostracoda analysis and chronological framework based on AMS¹⁴C data. Climate was cold and dry since 1972 yr.BP of the Holocene, which was mainly physical weathering and with a weak chemical weathering. The sedimentary discontinuity happened during 1352 yr.BP and 352 yr.BP, is seen as the size of the lake shrink, which is in consistent with the extremely low temperature and dry climate conditions during the global Glacier Time. From the study, we can conclude that the climate of Tibetan plateau was unstable during the last 2000 years, and extremely cold and dry event happened on Tibetan plateau during the warmer Holocene in China.

CO₂ expansion flooding technology has the potential to significantly enhance oil recovery in low permeability and ultra-low permeability reservoirs, while also facilitating carbon capture, utilization, and storage (CCUS) to a certain extent. This paper provides a comprehensive review of the mechanism of CO₂ expansion flooding, the current research status of two main methods – self-generated expansion with viscosity reduction and gas injection expansion with viscosity reduction - as well as advancements in simulation studies on expansion flooding. Currently, achieving optimal CO₂ flooding conditions remains challenging due to limited availability of large-scale gas sources and concerns regarding equipment pipeline corrosion during transportation. Finally, this environmentally friendly CO₂ flooding technology is summarized and its future prospects are discussed.

The temperatures of the phase transitions for polyethyleneterephthalate samples containing recycled PET (the product Vivilen) and the waste materials from its production were analyzed by differential scanning calorimetry and x-ray structural analysis, and the ratio of the crystalline and amorphous phases was determined. The polyethyleneterephthalate samples were arranged according to their glass transition and melting points, which made it possible to correlate the samples according to the degree of crystallinity. In order to obtain a filament based on the dust waste from the solid-phase polycondensation process an extrusion temperature regime was established, and samples of filaments for 3D printing that meet the requirements of GOST R 59100-2020 were obtained.

An investigation was carried out on the feasibility of obtaining a reagent based on complex compounds for regulating the parameters of a drilling mud by introducing complex‑forming ferrous cations into a sodium lignosulfonate composition followed by additional modification with phosphonic compounds and obtaining a polyelectrolyte complex derived from anionic polyelectrolyte‑sodium lignosulfonate and modified cationic starch. The presence of functional groups in the sodium lignosulfonate sample studied capable of complexation was established by IR spectrometry. The determination of the optimal ratios of the starting components for the obtaining complex compounds using lignosulfonate, iron sulfate, and phosphonic compounds was carried by mathematical modelling with the Statistica 12 software package. The surface activity of the experimental samples was studied by a stalagmometric method (drop count method). The particle size distribution method using an SALD‑7101 laser analyzer was employed to study changes in the structure of the macromolecule of sodium lignosulfonate and a polyelectrolyte complex derived from sodium lignosulfonate and cationic starch. Obtaining a stable polyelectrolyte complex by selecting the optimal ratios of the anionic and cationic components involved measuring the dependence of the impedance of an electrochemical cell on the alternating currency frequency. The best mole ratio for preparation of the polyelectrolyte complex was 1:1. Feasibility was studied for using this lignosulfonate reagent based on complex compounds as a reagent for regulating the drilling mud parameters in the temperature range from 20° to 160-180°C.