Vol 55, No 5 (2019)

Hydrothermal liquefaction (HTL) of microalgae biomass over an aluminum oxide catalyst with an isomerization component in the neutral and sulfated forms was studied. Gas-chromatographic — mass-spectrometric analysis of the products led to conclusions about the effect of catalyst composition on the gasoline-fraction group composition of the processed bio-oil. The contents of isoalkanes and aromatic hydrocarbons increased whereas the concentrations of S-, 0-, and N-containing components decreased in the HTL products if a catalyst was used. The yield of water-soluble side products also decreased. Sulfated catalysts had greater effects than neutral catalysts on the group composition.

The influence of wave (acoustic and high frequency electromagnetic) treatment of biomass—fuel oil—water three-component suspensions on the results of their gasification is investigated. The influence of gasification process implementation conditions on the yield and composition of the produced syngas was studied.

The changes in asphalt dispersed phase particle size in two-stage heavy resid oxidation process are studied. The influence of the temperature of each oxidation stage on the dispersed phase particle size is shown. The selection of the process parameters, which ensures formation of the smallest dispersed phase particle size and formation of sol-gel asphalt structure with the maximum stability factor and improved physicochemical properties, is validated. An idea of the chemical processes occurring during asphalt oxidation are proposed to be gained from the change in dispersed phase particle size.

Hydrocracking residue meeting physicochemical and chemical composition requirements for hydrocracking oil feedstock was studied. The optimal scheme for producing API group HI base oils was determined.

An adsorbent obtained by applying orthophosphoric acid to a peat surface was investigated during the refining of used mineral lubricating oil. The degree of regeneration (clarification) of the used oil depended on the adsorbent modification method, i.e., the acid/peat ratio, adsorbent/oil residue mass ratio, and mixing time of the phases.

The present work focused on increasing the yield, energy efficiency, and environmental friendliness of the existing (conventional) method for preparing fire-resistant fluids (FRFs). A series of fire-resistant phosphate esters were synthesized. The reaction occurred vigorously under much milder conditions even without a catalyst if anhydrous alcoholates/phenolates dispersed in an excess of an aromatic hydrocarbon solvent were used. The proposed synthetic method increased the yield of target product by —10% as compared with the conventional one. In addition, the phosphate esters obtained by this method were practically free of tars even before vacuum distillation and had acceptable color and optical density. The proposed technology for synthesizing phosphate esters could produce FRFs with the physicochemical and operating properties required to operate over broad ranges depending on the product application by varying the quantitative and qualitative compositions of the alcohols and/or alkylphenols. In particular, a mixed friary, phosphate with properties meeting basic regulatory requirements for use in power-plant turbine control and lubricating systems was produced.

Under the motor oil performance conditions, it is very difficult to determine the dispersing-stabilizing properties and the degree of dirtiness of the oil. These characteristics, however, have a great effect on the performance life of the oil until its replacement and the reliability of tractor and automobile operation. Relationships of changes in dispersing-stabilizing properties of motor oils with the content of additives and performance time in the engine were obtained by theoretical analysis and practical studies. The results of the studies on improvement of paper chromatographic method to determine the dirtiness of the oils under their performance conditions are presented.

In order to accurately predict the high-production areas in CBM reservoirs, we identified the main geological factors controlling the CHM production. Based on the statistical analysis data of the geological and production area and seismic prediction methods, the comparative influence of the five main geological factors was studied. The validity of the seismic prediction method was further evaluated. The results show that the production of a GEM well is influenced by the reservoir structure, gas content, permeability, and coal-body structure. The above four geological controlling factors can be accurately evaluated by the seismic attributes. The proposed high-production area seismic prediction method can be applied for accurate localization of the high-production areas. When the high-production evaluation index is lower than 0.2, the daily gas production exceeds 1000 The method can provide an effective instrument for evaluating formation productivity.

A NaNO₂/NH₄Cl heat generating system has been widely applied in oil production process in China, for paraffin plug removal, in-situ fracturing, etc. Establishing an accurate kinetic equation for the NaNO₂/NH₄Cl system is important for field operation applications. In this study, based on a strictly controlled group of experiments, the kinetic equation for the NaNO₂/NH₄Cl heat generating system is established and regressed by the method of undetermined coefficients, on condition that the heat loss of the reaction is relatively small and could be neglected. It is obvious that in many field applications the heat loss is considerably high and cannot be neglected; hence the equation is improved by taking into consideration the heat loss input. The improved equation shows a better correlation with experimental data, particularly for long reaction times. The established equation reveals the relationship between the reaction rate and the concentrations of the reactants and catalyst This study has practical significance for calculating the temperature field near the well bore and can be used for parameter optimization of the NaNO₂/NH₄Cl heat generating system.

The technology of TCP combined well testing is widely used in deepwater perforation and can cause string damage accidents. In order to improve the safety of the perforating string ANSYS/LS-DYNA software was used to analyze the influence of different parameters such as number of ammunition, tubing length, and the choice of perforation technology, on the tubing strength and deformation. Numerical simulation results show that the most vulnerable segment of the tubing is located at the bottom of the tube. The tubing length parameter can be effectively used to reduce the risk of tubing damage. The simulation model was verified by a field application case study.

A study was carried out on the effect of thickeners on the physicochemical properties of low-temperature greases. The dispersed phases were the lithium soap of stearic and 12-hydroxystearic acids, lithium soap of 12-hydroxystearic acid and 2-ethylhexyl borate, complex lithium soap of 12-hydroxystearic acid and azelaic acid, complex lithium soap of 12-hydroxystearic, sebacic, and boric acids, diurea, Aerosil, a polymer thickener and its hybrids with Aerosil.

The applicability of express methods for determining the effectiveness of solvents used for heavy oil recovery from carbonate reservoirs is studied. In the three-stage extraction method the wetting and extraction ability of the solvent in oil-saturated carbonate rock can be estimated from the surface tension of the solvent and the attenuation coefficient of the extract, respectively. In the method based on thin-layer chromatography the wetting and extraction ability of the solvent in oil-saturated carbonate rock can be estimated from the average boiling point and refractive index dispersion of the solvent. It was shown that the proposed methods can be used to arrange the solvents in order of their effectiveness in recovery of oil from carbonate reservoirs.

Alternative methods are examined for the removal of sulfur compounds from hydrocarbon fractions in order to meet the strict specifications for sulfur content and reduce the sulfur content in petroleum raw material. The advantages of such alternative sulfur removal methods include low temperature and pressure, no need for introducing hydrogen, and feasibility for small refineries. Two types of methods were examined. One type involves the use of adsorbents, selective solvents, oxidizing agents, and biodesulfilrization. The other group involves wave technologies based on electric pulse effects, cavitation, hydrowave, magnetic, and electromagnetic effects as well as combined wave technologies. The most effective methods for desulfurization yield fuel components corresponding to ecology class 5.

A large amount of oily cuttings is produced in the drilling process when the oil-based drilling fluid is used. The oil and oil-soluble additives adsorbed on the surface of the cuttings may pollute the environment. In this paper the method of silicic acid precipitation and formation of silicic acid micromicelles is used to encapsulate oil and to remove oil from the cuttings. The authors analyze the influence of the stirring time and the solution pH on the oil removal efficiency. When the pH is 2 and the stirring time is 10 min, the oil removal rate is 96%. Research into the mechanism shows the successive formation of silicic acid sol and gel in the process of silicic acid precipitation. The structure of the silicic acid micromicelles is characterized by scanning electron microscopy (SEA). The results of differential scanning calorimetry (DSC) indicate the existence of the exothermic decomposition peak of the hydrocarbons in the range from 350°C to 500°C, which proves that the micromicelle inner phase contains oil.