Том 53, № 5 (2017)

The oxidizabilities of the principal lignocellulose feedstock constituents (cellulose, lignin, xylan) and feedstock exposed to gamma-radiation are investigated. The oxidizability of wheat straw by hydrogen peroxide increases if the absorbed gamma-radiation dose is increased to 200-300 kGy and the feedstock particle size is reduced to 0.8-1.2 mm. Hemicelluloses are practically completely degraded by catalytic peroxide treatment (mass loss of ~95%) whereas lignin is destroyed much less (mass loss of ~27%) under the same conditions. Pretreatment of the feedstock increases the cellulose content in the lignocellulose feedstock and can be used to produce biofuels (EtOH or 2,5-dimethylfuran).

Joint thermal treatment of heavy oil and liquid products of fast wood pyrolysis is investigated. Thermal analysis shows that the coke yield does not increase if the liquid products are added up to 20 mass%. The liquid wood-pyrolysis products decompose much earlier than heavy oil. However, the decomposition of the blends is essentially the same as pure-oil decomposition.

The effectiveness of using used motor oil as the base for producing rolling oil is studied. A method is proposed for removing resins and aging products from the oil. The obtained results are analyzed. The composition of additives that acts as a triturating material and components that enhance the lubricating, wear-resistance, and protection properties of the rolling oil are determined. Acicular products of urea recrystallization are recommended as materials for fine polishing of parts; oleic acid, as the surfactant. It is shown that additional incorporation of graphenes into the rolling oil promotes running-in of engine parts.

Commercial cobalt-molybdenum catalyst after use for two years for diesel fraction hydrofining was oxidatively regenerated and activated with organic acids (citric and thioglycolic), ethylene glycol, and combined solution. It is shown that the main reasons for the loss of activity of the studied catalyst during its use are coke deposition on the catalyst surface and change in the properties of the applied active phase, which intensify in the oxidative regeneration process. Treatment of the oxidatively regenerated catalyst with solution of the studied reagents can fully restore the activity in the reaction of hydrodesulfurization of dibenzothiophene, and in the case where combined citric acid and ethylene glycol solution is used the observed hydrodesulfurization reaction rate constant exceeds the value obtained on fresh catalyst.

A synthetic oil-soluble iron-based catalyst was studied experimentally. A physical model of the catalytic transformation of high-viscosity oil at 200°C was developed. The composition and physicochemical and rheological characteristics of the thermocatalysis products were studied. IR spectroscopy found that the compositions of individual fractions changed. It was shown that the fraction of high-molecular-mass components could be substantially reduced by using the synthetic catalyst in combination with a hydrogen donor. This reduced the viscosity and; therefore, increased the degree of oil extraction.

The characteristics of the rheological behavior of the original road asphalt BND 60/90 and asphalt modified by an adhesive additive are determined. It is shown that the activation energy of viscous flow of asphalt increases on modification and that an extremum is observed at additive content of 0.8 wt. %. The additive exerts a cross-linking effect resulting from formation of a more uniform spatial disperse structure. In this case, the cross-linking effect manifests itself at a particular additive concentration (0.8 wt. %) at which the asphalt system attains the most active state. It is demonstrated that peptization of asphalt aggregates by additive molecules at a high strain rate effectively prevents recombination of the structural elements of the oil disperse system.

A 3D continuum simulation model of carbonate matrix acidizing is introduced to study the effect of different dimensions on the dynamic wormhole propagation process. The results obtained show that the wormhole propagation process passes through four stages – competition, dominant wormhole, wormhole breakthrough, and wormhole extension (injection pressure ratio dropping to 1%). In previous studies, the wormhole breakthrough stage was reported to occur when the injection pressure ratio had fallen to 3% instead of 1%. Wormhole simulation using 3D and 2D models at different injection rates indicate that the injection rate and breakthrough volume are optimal in both dimensions, the values of both parameters being higher in 2D than in 3D simulation. This trend is expected, since previous studies also show that the optimal rate and breakthrough volume are lower in 1D than in 2D simulation. CT scanning of limestone cores after acidizing show that the corresponding optimal breakthrough volume for a dominant wormhole is less than 3.1 pour volume (PV). The obtained data closely match the 3D simulation data (2.7 PV) and differ greatly from the 2D simulation data (10 PV). Based on the study, a higher-dimension model should be selected for simulating wormhole propagation and optimizing matrix acidizing as this can help improve the accuracy and efficiency of carbonate reservoir acidizing simulation.

Biodiesels and biomass EtOH are currently considered the most applicable and essential biomass fuels. Furthermore, MeOH and BuOH are also attracting attention as alternatives. These fuel types can be used to reduce exhaust emissions from gasoline engines because they are renewable oxygenated bioresources. Three biofuel additives, namely, MeOH (10%, M10), EtOH (10%, E10), and BuOH (10%, B10) were used to compare the engine performance properties and exhaust gas emission levels upon combustion of mixed biomass fuels and pure petroleum fuel (clean unleaded gasoline, E0). The engine combustion temperature dropped by 4.32%, O₂ emission increased by 6.67%, NO_x emissions decreased by 13.46%, CO emission decreased by 44%, and hydrocarbon emissions fell by 29% if biomass fuels were used. Therefore, mixed biofuel additives and gasoline could substantially reduce engine exhaust emissions, including oxides of C and N, hydrocarbons, etc., because the biofuels contain higher oxygen contents that facilitate complete combustion.

In this project, we have experimentally studied the combustion characteristics of commercial refined biodiesel and 0# diesel. Combustion of these two types of flammable liquids was carried out in a calorimeter to measure their heat release rate. The results showed that the heat release rate, which is one of the most significant properties in studying combustion, varies significantly depending on the samples and the dimensions of the circular burner. With the aim of evaluating the combustion characteristics, we also determined and analyzed other key properties of the fuels such as flash point, total heat release, and mass loss rate, which reflect the fire hazard. The results provide an experimental basis for developing fire protection measures during use, storage, and distribution of biodiesel. The flash point of biodiesel is higher than for 0# diesel, while the heat release rate, the experimental total heat release, the average combustion temperature and the radiation of biodiesel are lower than for 0# diesel.

Recently, gas-hydrate storage technology has been drawing increasing attention as a new means of gas storage and transportation and may in the future become the optimal means of gas storage as compared with LNG technology because of its economic and safety advantages. The main purpose of the present work was to investigate experimentally the hydrate dissociation mechanism using a kinetic model at different temperatures and atmospheric pressure in the range 5-15°C. The obtained results have great significance for gas-hydrate storage technology and its application in industry.

A self-diverting fracturing technology is proposed in the study as a way of effectively creating a stimulated reservoir volume. The technology, which is based on the use of a novel self-diverting fracturing fluid, can create and extend fractures to design shapes, is strong enough to effectively plug fractures and can then be effectively removed from fractures and form a branched network of highly permeable fractures. It can also greatly enlarge the stimulated reservoir volume, possesses excellent injecting and plugging capacity, effective diversion and complete self-plugging ability, produces little reservoir damage, and is simple and practical. Gelling and gel-breaking macrophenomena, temporary plugging, diversion, and fluid loss are described in detail. All the test results demonstrate that the present self-diverting fluid fracturing technology possesses many advantages.

Crude oil and heavy petroleum products are oil disperse systems whose properties depend largely on their thermodynamic state. To determine the thermodynamic parameters and aggregative stability of oil disperse systems, it is proposed to use the inverse gas chromatographic method, which allows calculation of the free surface energy, entropy, and enthalpy of the oil disperse systems from the retention volume.

The situation evolved in the domain of fuel additives production during 2011-2015 is reviewed through the analysis of literature and patent sources and statistical data. The main trends in development of additives are determined and the main types of additives are characterized. It is noted that the interest of developers worldwide was focused on additives of biocomponents (oxygenates and biodiesel). In Russia, where imported additives were prevalent until recently, active process of import substitution has begun. The additive demand of Russian refineries for the production of modern quality fuels is analyzed and the domestic developments are characterized. Technical solutions that offer alternatives to the use of additives are proposed.

The reprecipitation of cellulose from alkaline solutions was studied. The influence of the following factors on cellulose specific surface area was investigated: temperature, precipitant concentration, cellulose concentration in a stock alkaline solution, rate of precipitation, and presence of polyethylene glycol. After considering the results of regression analysis, the effects of different parameters on cellulose specific surface area were determined. The ratio of crystalline and amorphous phases in cellulose before and after reprecipitation was determined by XRD analysis.

The author’s affiliation should read Mining Technology Institute, Taiyuan University of Technology, Taiyuan 030024, China. Email: zhaojianzhong@tyut.edu.cn