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Date submitted2024-04-10
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Date accepted2024-06-03
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Date published2025-04-25
Combined method for processing spent acid etching solution obtained during manufacturing of titanium products
Possessing high strength, low density and significant chemical resistance, titanium has found wide application in various fields of the national economy – the chemical industry, aviation and rocket technology, mechanical engineering, medicine, etc. The production of titanium products is hampered by a fairly strong oxide film covering its surface. Removal of the oxide film from the surface of titanium workpieces is carried out by etching in solutions of mineral acids of various compositions. A spent acid etching solution (SAES) is formed, containing titanium salt and the remainder of unreacted acids. Almost all etching solutions contain HF and one of the strong acids. This is H2SO4, HCl or HNO3. Thus, the SAES includes ions of titanium, fluorine or chlorine, orsulfate, or nitrate. SAES is quite toxic and must be diluted or cleaned several times before being discharged into a reservoir. Most of the methods used to extract impurities contained in SAES lead to a decrease in their content. As a result of such purification, there is a loss of substances contained in SAES in significant quantities and of interest for further use. The work presents experimental results obtained from the combined processing of SAES containing titanium fluoride, hydrofluoric and hydrochloric acids. At the first stage, SAES is treated with sodium hydroxide. The resulting titanium hydroxide precipitate is filtered off. At the second stage, the filtrate containing sodium fluoride and chloride is processed in a membrane electrolyzer. In this case, not only the extraction of sodium salts from the filtrate occurs, but also the production of sodium hydroxide and a mixture of hydrofluoric and hydrochloric acids. Sodium hydroxide can be used for processing SAES, and a mixture of acids for etching titanium workpieces.
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Date submitted2023-03-02
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Date accepted2023-06-20
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Date published2023-07-19
Improving the efficiency of autonomous electrical complex with renewable energy sources by means of adaptive regulation of its operating modes
Renewable energy sources are gradually becoming useful in mining industry. They are actively used in remote, sparsely populated areas to power shift settlements, geological and meteorological stations, pipeline equipment, mobile cell towers, helicopter pads lighting, etc. In comparison with diesel generators, systems with renewable sources do not require fuel transportation, have short payback periods and flexible configuration for different categories of electrical loads. The main obstacles to their spread are instability of generation and high cost of produced electricity. One of the possible ways to solve these problems is to develop new technologies, increase power density of generators and energy storage systems. The other way represents energy saving and rational use of affordable resources. The new solutions for implementation of the second method are proposed in this work. The object of the study is autonomous DC electrical complex with photovoltaic and wind power sources. In such systems the generated power from renewable sources is transferred to consumers via intermediate DC bus, the voltage level of which affects the power losses in the process of power transmission. The vast majority of complexes have a problem that their DC bus voltage is constant, while the optimum voltage level with lowest losses varies depending on the generated and consumed power. Therefore, electrical complexes potentially lose a part of the transmitted energy. To avoid this, a special algorithm was added to automatically adjust DC bus voltage to optimum level according to changes in working conditions. An additional contribution to efficiency improvement can be made by dynamic change of operating frequency in power converters depending on their load. The evaluation based on results of computer simulation showed that in a complex with rated power 10 kW active power losses during its lifetime can be reduced by 2-5 %.
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Date submitted2023-04-02
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Date accepted2023-06-20
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Date published2023-07-19
Integration of renewable energy at coal mining enterprises: problems and prospects
This article addresses the issue of developing renewable energy in coal mining enterprises in the Russian Federation. The study presents a methodology for assessing the technical and economic efficiency of introducing renewable energy sources based on simulation modeling. An analysis of the potential of solar and wind energy for coal mining regions in Russia is conducted. The authors use a custom software developed by them to simulate the power supply system for various scenarios of renewable energy integration, including solar generation, wind generation, solar generation with energy storage, wind generation together with solar generation. Based on the example of the Rostov region, a feasibility study of the considered options is presented. Additionally, the research includes a sensitivity analysis of the investment project in the conditions of uncertainty in the development of Russian renewable energy. The research findings indicate that even in market conditions with CO2 emission quotas and prices at the level of the Sakhalin experiment, renewable energy in coal mining enterprises in Russia remains unattractive and requires additional support.
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Date submitted2020-05-13
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Date accepted2020-06-24
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Date published2020-10-08
Barriers to implementation of hydrogen initiatives in the context of global energy sustainable development
Modern trends in the global energy market linked to the Sustainable Development Goals often lead to the adoption of political decisions with little basis in fact. Stepping up the development of renewable energy sources is an economically questionable but necessary step in terms of its social and ecological effects. However, subsequent development of hydrogen infrastructure is, at the very least, a dangerous initiative. In connection with mentioned above, an attempt to examine hydrogen by conducting an integral assessment of its characteristics has been made in this article. As a result of the research conducted, the following conclusions concerning the potential of the widespread implementation of hydrogen in the power generation sector have been made: as a chemical element, it harms steel structures, which significantly impedes the selection of suitable materials; its physical and volume characteristics decrease the general efficiency of the energy system compared to similar hydrocarbon solutions; the hydrogen economy does not have the necessary foundation in terms of both physical infrastructure and market regulation mechanisms; the emergence of widely available hydrogen poses a danger for society due to its high combustibility. Following the results of the study, it was concluded that the existing pilot hydrogen projects are positive yet not scalable solutions for the power generation sector due to the lack of available technologies to construct large-scale and geographically distributed infrastructure and adequate international system of industry regulation. Thus, under current conditions, the risks of implementing such projects considerably exceed their potential ecological benefits.
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Date submitted2019-05-07
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Date accepted2019-07-11
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Date published2019-10-23
Operation of a Single-phase Autonomous Inverter as a Part of a Low-power Wind Complex
- Authors:
- A. A. Belsky
- V. S. Dobush
- Shaiban Fuad Haikal
The article discusses the experience of operating a wind power complex with a low-power wind power installa- tion (5 kW), the use of which is promising for powering remote oil production facilities, exploration and other types of mining operations. The structure of the studied complex and its characteristics, technical problems that have arisen during operation for 6 years are given. The elements of the wind energy complex – the battery charge regulator and the inverter-converter are considered. The consequences of the mechanical regulator failure of battery charge are con- sidered and recommendations for its replacement are presented. The issues of diagnostics and repair of one of the main elements of the complex – the inverter-converter, its component – DC link are highlighted in detail. Oscil- lograms of the output voltage of the inverter-converter are presented for different capacities of the DC link and the images of the repaired inverter-converter are given. Recommendations are given on choosing an inverter-converter and setting up the operating modes of the wind energycomplex.
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Date submitted2015-10-03
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Date accepted2015-12-10
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Date published2016-08-22
Directions and prospects of using low grade process fuel to produce alumina
- Authors:
- O. A. Dubovikov
- V. N. Brichkin
Power consumption across the globe is constantly increasing for a variety of reasons: growing population, industrialization and fast economic growth. The most widespread gaseous fuel – natural gas – has the low production cost. It is 2-3 times cheaper than liquid fuel production and 6-12 times cheaper than coal production. When natural gas is transported to distances from 1.5 to 2.5 thousand km by the pipeline, its cost with account of transportation is 1.5-2 times less than the cost of coal and the fuel storage facilities are not needed. Plants powered by natural gas have the higher efficiency as compared to the plants operating on other types of fuel. They are easier and cheaper to maintain and are relatively simple in automation, thus enhancing safety and improving the production process flow, do not require complicated fuel feeding or ash handling systems. Gas is combusted with a minimum amount of polluting emissions, which adds to better sanitary conditions and environment protection. But due to depletion of major energy resources many experts see the future of the global energy industry in opportunities associated with the use of solid energy carriers. From the environmental perspective solid fuel gasification is a preferred technology. The use of synthetic gas was first offered and then put to mass scale by English mechanical engineer William Murdoch. He discovered a possibility to use gas for illumination by destructive distillation of bituminous coal. After invention of the gas burner by Robert Bunsen, the illumination gas began to be used as a household fuel. The invention of an industrial gas generator by Siemens brothers made it possible to produce a cheaper generator gas which became a fuel for industrial furnaces. As the calorific value of generator gas produced through gasification is relatively low compared to natural gas, the Mining University studied possibilities to use different types of low grade process fuel at the Russian alumina refineries as an alternative to natural gas, access to which is restricted for some of the regions.
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Date submitted2014-07-21
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Date accepted2014-09-19
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Date published2014-12-22
Preliminary preparation of oil for primary processing
Oil supplied for primary processing always undergoes preliminary preparation, the purpose of which is to eliminate the harmful effect of water and salt contained in the oil. It is thought that corrosion of the equipment is connected mainly with chlorides of magnesium and calcium, which are subjected to hydrolysis with the formation of hydrochloric acid. Under the influence of hydrochloric acid the destruction (corrosion) of metal equipment at technological plants occurs (especially refrigerating-condensing and heatexchange equipment, furnaces of rectification units etc.). The authors of the article, on the basis of thermodynamic calculations, provide their point of view on this process and give a methodology by which the process of preliminary oil dehydration and desalting can be controlled. The thermodynamic calculations executed for standard conditions on the basis of refer-enced data confirm a high probability of chemical interaction of iron with hydrogen ions, hy-drogen sulphide and especially with carbonic acid. This testifies to high activity of the carbon dioxide dissolved in water and the impossibility of hydrolysis of ions of magnesium, calcium and iron. The calculations show that only the hydrolysis of magnesium chloride is possible tak-ing into account the ionic composition of the water phase in the oil. It should be noted that the presence of ions of chlorine shifts the iron potential in a nega-tive direction and increases the speed of corrosion of petrochemical equipment. The solution of this problem is in the development of modern methods of crude oil dehydration and desalting. It is also, however, in an intensification of the processes of mixing water-oil emulsions with wash-ing water by using various physical fields (for example, ultrasound) and creating new effective mixing devices on the basis of them.
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Date submitted2009-09-05
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Date accepted2009-11-17
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Date published2010-06-25
Photoelectric method of hydrogen detection
The new photoelectric method of the detection of hydrogen is proposed, based on strong dependence of the photo induced current on concentration of hydrogen in III-V heterostructures with Pd contact. The given influence at a room temperature is stronger on few orders than influence of hydrogen on electric characteristics of solid-state elements in existing sensors. The original design of portable sensor module was developed on the base of photosensitive element and infrared light-emitting diode that meet demands of hydrogen power engineering.
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Date submitted2008-11-29
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Date accepted2009-01-30
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Date published2009-12-11
World experience in power industry reforming in a format of fuel-energy comlex
- Authors:
- A. Y. Nikolaeva
The paper highlight the most valuable for Russia economically developed countries experience of power industry reformation. There are prerequisites, goals and tasks of reformation, made transformations essence and their results and consequences.