Modern Power Engineering Research Articles

Thermal and aerodynamic characteristics of air cooled condenserfor steam turbine power unit

THE PURPOSE. Increased water consumption at power plants leads to a deterioration of the environmental situation not only in countries with limited water supply sources, but also in countries with significant reserves of fresh water. There is a need to consider the possibility of using an air condenser as an alternative use in industrial water supply systems at a power plant. To present a methodology for calculating the main characteristics of a condenser (condensation and reflux sections), to estimate the aerodynamic resistance and fan power for an air-cooled condenser as part of a steam turbine power unit. Determine the influence of air temperature and pressure in the condenser on the calculation of the air condenser. To develop recommendations for the selection of parameters of air condensers operating as part of steam turbine power units. METHODS. Methods for designing heat exchangers, modeling and intensifying heat exchange processes were used in the course of calculating an air condenser unit. RESULTS. A method for calculating an air-cooled condenser for a 110 MW condensing turbine has been developed. The analysis of the calculation of the heat transfer coefficient is given. The analysis of the values of the heat exchange area of the condensing unit is presented. The effect of pressure in the condenser on the main calculated characteristics of the condenser is shown. Recommendations for the selection of the fan capacity in the condenser and the design temperature of the cooling air have been developed. CONCLUSION. The issue of using air coolers in the power industry is still poorly covered in the literature, however, environmental problems and the shortage of fresh water are becoming more and more urgent all over the world. The development of air-cooling systems is a very topical issue for modern power engineering. It is shown that for stationary installations of condensation of water vapor, the most suitable is the hipped-roof arrangement of the heat-exchange sections with the lower arrangement of the fans. Quantitative estimates of the change in the heat transfer coefficient and the area of the heat-exchange surface are given for the pressure range of 8…20 kPa. The power consumption of the fan depends significantly on the temperature of the cooling air and the vacuum in the condenser.

Combustion in a chamber furnace with a tangentially swirling vortex

Relevance. The need to analyze the furnace processes in boiler units with vertical vortex when arranging pulverized coal combustion with the enhancement of environmental parameters through the installation of tertiary blast nozzles. Despite the carbon-free policy in modern power engineering coal remains one of the main sources of energy, so the reconstruction of boiler units in order to reduce harmful emissions is very relevant. Aim. To study aerodynamics and combustion processes of pulverized coal fuel in the furnace chamber of a boiler unit with a tangential arrangement of burner devices using a combustion scheme with tertiary air blowing. Methods. The Eulerian–Lagrangian approach was applied to numerical study of flow characteristics, heat transfer and combustion in a furnace with a tangential burner arrangement. Also, k-ε model of gas turbulence, particle-turbulence interaction, diffusion model of particle dispersion, P-1 radiation modeling method and pulverized coal particle combustion model based on global particle kinetics and experimental data were used for numerical calculations. Results. Based on numerical calculations and analysis, the dependences of combustion product concentrations, temperature, hydrodynamics at combustion of Kuznetsky coal grade D in the furnace chamber with tangential arrangement of burners for brown coal, as well as at installation of tertiary blast nozzles have been obtained. Insufficient redistribution of air between burners and tertiary nozzles is revealed, as for maintenance of stable twist of vertical vortex and accordingly presence of high values of velocities at the outlet of burner devices it is not possible to increase the portion of tertiary air without reconstruction of burners. It is also established that the volume of the furnace chamber below the burners is poorly involved in heat exchange.

Advanced Optimisation and Forecasting Methods in Power Engineering—Introduction to the Special Issue

Modern power engineering is struggling with various problems that have not been observed before or have occurred very rarely. The main cause of these problems results from the increasing number of connected distributed electricity sources, mainly renewable energy sources (RESs). Therefore, energy generation is becoming more and more diverse, both in terms of technology and location. Grids that have so far worked as receiving networks change their original function and become generation networks. The directions of power flow have changed. In the case of distribution networks, this is manifested by power flows towards transformer stations and further to the network with a higher voltage level. As a result of a large number of RESs, their total share in the total generation increases. This has a significant impact on various aspects of the operation of the power system. Voltage profiles, branch loads, power flows and directions of power flows between areas change. As a result of the random nature of RES generation, there are problems with the quality of electricity, source stability issues, branch overloading, voltage exceedances and power balance. The occurrence of various types of problems requires the use of more and more advanced methods to solve them. This review paper, which is an introduction to the Special Issue Advanced Optimisation and Forecasting Methods in Power Engineering, describes and justifies the need to reach for effective and available mathematical and IT methods that are necessary to deal with the existing threats appearing in the operation of modern power systems. It indicates exemplary, current problems and advanced methods to solve them. This article is an introduction and justification for the use of advanced calculation methods and algorithms. Engineering intuition and experience are often not enough due to the size and complexity of power grid operation. Therefore, it becomes necessary to use methods based on artificial intelligence and other advanced solutions that will facilitate and support decision making in practice.

Destruction of polymer insulation and threshold amplitudes of current pulses of different temporal shapes for electric wires and cables in the low- and high-current circuits of pulse power engineering, electrical engineering and electronic devices

Goal. Development of engineering method for settlement of threshold amplitudes Impk of single-pulse current ip(t) of different temporal shapes for electric wires and cables with polyethylene (PET), polyvinylchloride (PVC) and rubber (R) half-length insulation, used in modern pulsed power engineering, electrical engineering and electronics in their low- and high-current circuits. Methodology. Basis of the theoretical and applied electrical engineering, electrical power engineering, electrophysics bases of technique of high-voltage and large pulsed currents, bases of low- and high-current electronics, measuring technique, electromagnetic compatibility and standardization. Results. Development of engineering method is executed on close calculation determination of threshold amplitudes Impk of single-pulse axial-flow current ip(t) of different temporal shapes for electric wires and cables with copper (aluminum) current-carrying parts and PET, PVC and R half-length insulation, used in the ow- and high-current circuits of pulsed electrical power engineering, electrical engineering and electronics. Electrothermal resistibility of half-length insulation of the examined cable and wire products (CWP), proper maximum to the possible temperatures of heating of current-carrying and insulating parts of the probed wires and cables and shutting out the offensive of the phenomenon destruction in the indicated insulation of CWP, was fixed based on this method. Calculation analytical correlations are obtained for finding in probed CWP of threshold numeral values of Impk amplitudes of pulses of current ip(t), time-varying both on aperiodic dependence of type τf/τp with duration of their front τf and duration of their pulses τp and by law of exponential attenuation sinewave. It is shown that at Imp>Impk destruction of their half-length insulation, resulting in the decline of service life of CWP, will come from the thermal overheat of current-carrying parts of the examined electric wires and cables. The examples of practical application of the offered method are resulted upon settlement for a radiofrequency coaxial cable RC 50-4-11 with middle sizes is easily soiled with continuous PET insulation of threshold amplitudes of Impk of standard aperiodic pulses of current ip(t) from nano-, micro- and millisecond temporal ranges of shape of τf/τp=5 ns/200 ns, τf/τp=10 μs/350 μs and τf/τp=7 ms/160 ms. It is shown that with the proper growth of parameter τp>>τf for flow on a continuous copper tendon and split copper shell of radiofrequency coaxial cable RC 50-4-11 with middle sizes is easily soiled indicated homopolar pulses of current ip(t) substantial diminishing of their threshold amplitudes of Impk (with 531,2 кА for the nanosecond pulse of current of type 5 ns/200 ns to 1.84 кА for the millisecond impulse of current of type of 7 ms/160 ms takes place). Originality. An engineering method is first developed for close settlement of threshold numeral values of Impk amplitudes of single-pulse axial-flow current ip(t) of arbitrary peak-temporal parameters for electric wires and cables with copper (aluminum) current-carrying parts and PET, PVC and R half-length insulation. Practical value. Application in electrical engineering practice of the offered engineering method for determination of threshold amplitudes Impk of the indicated pulses of axial-flow current ip(t) for the probed electric wires and cables will allow considerably to increase service life of examined CWP.

Evaluation of the structural stability of welded joints in welding

Brittle (intergranular) destruction of the heat-affected zone metal (local failure) of welded joints of power equipment during welding and heat treatment (tempering) was an unexpected and serious problem. Its solution based on the development of progressive technological solutions is an urgent task of modern power engineering. The article considers an applied method of fluctuation analysis for assessing the stability of the structure and the probability of local destruction (LD) of the metal of the heat-affected zone (HAZ) of thick-walled welded structures of power equipment made of low-alloy steel 15Kh2NMFA. A computational - experimental method for calculating the range of optimal values of heat input is stated. The LD mechanism is stated and its connection with the technology and thermal conditions of welding and the structural stability of the HAZ metal is established. It was found that the growth of austenite grains of the HAZ metal stimulates the tendency to LD, if a dendrid-type carbide phase is precipitated at grain boundaries during welding. By optimizing the heat input during welding, it is possible to control the structural and chemical homogeneity of the HAZ metal and the associated tendency to form LD.

A comparative analysis of the characteristics of the water removal processes in preparation for incineration of typical wood waste and forest combustible materials

The article presents the results of the experimental studies of the processes of removing moisture from fairly typical and widespread forest combustible materials, and woodworking waste under conditions of their thermal preparation for combustion. Based on the results of the experiments, the main regularities of the drying processes of woody biomass under conditions of radiation-convective heating have been established. The integral characteristics (characteristic times) of the drying process of forest biomass under typical (for this technology) heating conditions have been determined. The experiments were carried out on equipment that provides a low level of error (less than 3.3%) for determining the main characteristics of the biomass dehydration process. The values of the mass rates of moisture removal (Weva) of four promising (for modern and future power engineering) and fairly common types of biomass have been established in the ambient temperature range from 333 to 393 K, which corresponds to the operating modes of the drying equipment of power plants. According to the results of the experiments, it was shown that at relatively moderate ambient temperatures (333≤ Tg ≤ 353 K), the type of wood has a rather significant effect on the characteristics and conditions of the dehumidification process. At the same time, the process of drying wood chips is much faster compared to other types of biomass. As the ambient temperature rises (at 373≤Tg ≤ 393 K), the influence of the type of biomass decreases. As a result of the experiments, a physical model of the process of removing moisture from the bulk layer of biomass was formulated. According to the results of the experiments, it was found that before burning forest biomass in boilers of thermal power plants, it is most advantageous to carry out drying in conditions of relatively moderate (at 333≤Tg ≤ 353 K) ambient temperatures. The studies carried out provide grounds for justifying the use of forest combustible material as fuel (or one of the components of the fuel mixture) at thermal power plants currently operating on coal.

Electrophysical properties of mixtures of mineral oil and synthetic ester dielectric liquid

Power transformers are key equipment in power generation, transmission, and distribution systems. The reliability of power transformers is based on the performance of the insulation system, which includes solid cellulose insulation and a liquid dielectric. Modern power engineering requires liquid insulation to have excellent insulating properties, high fire resistance, and biodegradability. Mineral oil that has been in use for over 100 years does not meet certain requirements. Therefore, various methods of enhancing the insulating properties of the oil are currently being considered, including mixing it with other liquid dielectrics, which have excellent properties. Synthetic and natural esters are considered as alternative fluids.This article discusses the possibility of enhancing the insulating characteristics of mineral oil with a high content of aromatic hydrocarbons (for example, T-750 oil) by mixing it with synthetic ester Midel 7131. Assessment is given of insulating parameters of the resulting mixtures with an ester fraction in mineral oil from 0% to fifty%. The main characteristics of the mixtures are described, such as density, kinematic viscosity, flash point, dielectric loss tangent, relative dielectric permittivity, breakdown voltage, and moisture content. It is shown that with an increase in the proportion of ester, some parameters of the obtained insulating liquid improve (flash point, dielectric constant, breakdown voltage), while values of other parameters (density, kinematic viscosity, dielectric loss tangent) with an ester content of more than 10% in the mixture do not meet the requirements for mineral oils.

Development of an algorithm of implementation of programs of repair of steam boilers and turbines of TPPs based on technical condition of power equipment

Deterioration and aging of the technical fleet of thermal power facilities lead to an unpredictable shutdowns of power equipment. Therefore, it is necessary to create a special approach in maintenance and repair programs, taking into account the possibility of predicting the moment of onset of the defect, its development, as well as the time of possible equipment failure. The equipment maintenance system used at the enterprises is based on the collection of retrospective data on defects and failures on the main and auxiliary equipment of the TPP and summarizing statistics on identical or similar equipment samples. Analysis of domestic and foreign methods of maintenance and organization of repair, as well as possibility of their application in modern power engineering is given. In order to create an efficient production asset management system, which addresses the problem of finding a balance between the potential risk of losses associated with both the operation of equipment and the cost of correcting defects, new class systems are now used in the software market, which carry out equipment maintenance based on the forecast. In order to optimize the equipment maintenance system and ensure uninterrupted and reliable operation of the equipment at minimum operating costs, as well as to reduce equipment downtime, unscheduled and emergency operations, it is advisable to use a modern approach to manage both reliability and risk, as well as the cost of asset ownership. This will enable to control the economic efficiency of the use of production assets. The necessity of creation of an algorithm of implementation of repair programs of power equipment base on technical condition for its use in digital power systems is shown. An algorithm is proposed for implementing the repair program of power units of electric power plants, including steam boilers and turbines of thermal power plants, differing by taking into account the technical condition of power equipment, which allows recognizing the defect that has appeared, determining the cause of its occurrence, its evolution and the duration of possible equipment failure. In the developed repair maintenance algorithm, it is proposed to make a transition from statistical empirical assessments of the technical condition of the equipment to objective estimates obtained on the basis of automated technical diagnostics systems and predictive analysis of situations.

Цифровая коррекция показаний измерительных каналов уровня жидких сред с областью нечувствительности датчиков на атомных электрических станциях

The introduction and development of computerized digital systems in modern power engineering has led in Russia to a full modernization of domestically produced nuclear power plant measurement systems. In particular, digital methods for correcting the readings of hydrostatic level sensors have been widely put in use since 2013. The experience gained from putting them in use was generalized in the reference and organizational and methodological literature in 2017. However, the subsequent results of preoperational adjustments carried out at newly designed nuclear power units and at those under construction have shown that some issues still remain unresolved in this application field. In particular, there is a need is to develop digital methods for correcting the readings produced by channels measuring the level of liquid media in pressurized process tanks if there occurs a sensor dead zone. The complexity of this problem is stemming from the fact that it is not possible to take the sensor dead zone into account by introducing a constant correction to the measurement channel readings in view of the technological process peculiarities. Thus, during the operation of nuclear power units, the water density in pressurized process tanks and vessels decreases from 980 to 590 kg/m3, and the vapor density increases from 0 to 100 kg/m3. Such changes give rise to complex thermal and physical interphase processes that occur under the conditions of large mass transfers of the vapor--water mixture. As a result, the sensor's dead zone boundary undergoes an essential change in the tank longitudinal section depending on the current values of the working fluid thermal and physical characteristics. To solve this problem, digital methods for online correction of measured level readings are proposed that take into account changes in the two-phase working medium (vapor--water) in the course of a continuous technological process. Nowadays, the introduction of digital methods for correcting the hydrostatic level sensor readings is especially relevant in connection with the development of industry programs aimed at increasing the capacity of newly designed and operating nuclear power units, which pose more demanding requirements to the accuracy of thermal and physical measurements and operational safety as a whole.

Sizing the thermal energy storage (TES) device for organic Rankine cycle (ORC) power systems

Thermal energy storage (TES) became one of the main research topics in modern power engineering. The design of TES devices and systems depend on their application. Different thermal energy storage materials (e.g., solids, liquids, or phase change materials) can be applied in TES devices. The selection of the thermal energy storage material depends mainly on the thermal power and operating temperature range of the TES device. These devices and systems are applied in different energy conversion systems, including solar power plants or combined heat and power (CHP) stations. The application of TES devices is also considered in the case of other industries, such as metallurgy. The possible application of TES devices is particularly promising in the case of organic Rankine cycle (ORC) systems. These systems are often utilizing floating heat sources such as solar energy, waste heat, etc. TES device can be therefore applied as the evaporator of the ORC system in order to stabilize these fluctuations. In this paper, the possible thermal energy storage materials used in TES devices applied in ORCs are discussed. Moreover, the modelling results are reported related to assessment parameters which can be applied to size the TES device for ORC system utilizing different low-boiling working fluids. The thermal properties of working fluids are taken from CoolProp. The function of heat capacity of different TES materials is also provided and the calculation is computed by employing MATLAB. The result shows that based on the simulation, the gradient of the natural characteristic of TES with working fluids (ζ(Tb)) tends to decrease. The presented result in this paper gives a new point of view which can be used by scientists and engineers during the design and implementation of TES evaporators dedicated to ORC power systems.

ВЗАЄМОДІЯ ГРАВІТАЦІЙНИХ ХВИЛЬ З ПРИПЛИВНОЮ ЕЛЕКТРОСТАНЦІЄЮ

Використання відновлюваних джерел енергії є нагальним та актуальним у життєдіяльності людства в сучасних умовах паливо-енергетичної кризи та забруднення навколишнього середовища. Одним із типів відновлюваних джерел енергії є припливні електростанції, в яких використовується потенційна енергія припливів і відливів. Визначення особливостей взаємодії хвильової течії з конструкціями припливної електростанції та створення умов безаварійної та ефективної роботи таких станцій є, безумовно, актуальною проблемою в сучасній енергетиці. Метою досліджень є визначення впливу гравітаційних хвиль на конструкцію припливної електростанції та розроблення рекомендацій щодо безпечних умов експлуатації припливної електростанції. В роботі проводяться чисельні та експериментальні дослідження взаємодії хвильової течії зі спорудами припливної електростанції та дамбою, яка огороджує закриту акваторію. Для цього використано сучасний апарат теоретичної гідромеханіки, теорії ймовірностей та математичної статистики, створено експериментальний стенд і проведені лабораторні дослідження в хвильовому басейні, де генератор хвиль генерував гравітаційні хвилі заданих параметрів. Проведені візуальні дослідження і визначені інтегральні та спектральні характеристики полів швидкості та тиску. Отримані гідродинамічні характеристики хвильового руху та течій через турбінні тракти електростанції і їх спектральні складові. Визначені поля тиску, навантаження і перекидуючих моментів сил на будівлю станції та встановлені особливості розмиву ґрунту у місці спряження станції та дна водойми. Проведені оцінки характеристик розмиву піщаного ґрунту поблизу припливної електростанції. Розроблені рекомендації щодо безаварійної роботи припливної електростанції та визначені оптимальні товщини піщаної подушки та кам’яної берми, на яких будується станція. Бібл. 20, рис. 5.

Modern methods of intensification of heat exchange processes in plate apparatuses

The heat supply system of the Russian Federation is characterized by significant wear and tear of equipment: heating networks and boilers. At the same time, an important element of heat supply systems equipment is heat exchangers of various designs, which are used in boilers, IHP, thermal power plants, and nuclear power plants. Various heat exchange equipment used in modern heat power engineering is considered. It is established that the use of plate heat exchangers is a more appropriate engineering solution than shell-and-tube heat exchangers, due to economic factors and operational advantages. The method of intensification of heat transfer of the heated liquid by means of technological depressions of spherical shape located according to the linear law is considered.

ENSURING THE QUALITY OF MANUFACTURING GEAR TRANSMISSIONS IN POWER MECHANICAL ENGINEERING

The development of modern power engineering goes along the line of continuous increase of speeds, efficiency and power units. Gears and gearboxes are crucial parts of modern mechanisms and occupy an important place in the domestic power engineering industry. The strength and durability of gears, in addition to design factors, to a large extent depends on the processing techniques. The final stage of manufacturing such wheels is the gear grinding operation. In the process of tooth-grinding, complex and unique thermomechanical processes take place in the thin surface layer. As a result of short-term heating to high temperatures, structural transformations, called prizhogami, occur in such a surface layer, and in some cases even micro and macro-cracks. In addition, there are cases of manufacturing gears with hidden grinding defects (for example, the appearance in the surface layer of teeth of large tensile stresses), which reduces the service life, and in some cases causes the teeth to break under operating conditions. The development of effective measures to ensure the quality of the surface layer during a gear grinding operation largely depends on the ability to predict (or calculate) temperatures and residual stresses along the depth of the cemented tooth layer. A method for calculating the internal residual stresses arising during gear grinding of wheels from cemented steels is proposed. On the basis of the performed calculations and experiments, the ways of improving the quality of manufacturing the working surfaces of gears used in units of thermal and nuclear power plants are proposed and substantiated.

Формування відповідальності майбутнього фахівця – найважливіша вимога професійної підготовки сучасних студентів-енергетиків

Формування відповідальності майбутнього фахівця – найважливіша вимога професійної підготовки сучасних студентів-енергетиків

Influence of the Environment on the Operational Safety of a Fluidized Bed Boiler

Abstract The use of fluidized bed boilers in modern power engineering is a promising solution for clean and economically acceptable combustion of various fuels, including coal, biomass and waste, for the generation of electricity. The fluidized bed boilers are nowadays technically advanced and complex combustion facilities where all individual boiler elements are subjected to withstand continuous structural and thermal loads during their operation. Intensive loading of boiler elements can be quite easily linked with boiler operational safety and is quite often one of the main reasons for emergency shutdowns followed by necessary replacements of the damaged items. In case of industrial large-scale circulating fluidized bed boilers the frequency of unplanned shutdowns is also quite often affected by the hydrodynamics of the fluidized bed and some other parameters, such as the intensity of solids circulation, temperature, solids concentration, flue gas composition and velocity, solids accumulation and deposition, as well as the corrosion or erosion of heat transfer surfaces. The present paper briefly reports the results of authors investigation focused on the morphology and structure of some chosen elements (steel anchors) sampled from one of Polish circulating fluidized bed boilers. The anchors were degraded during boiler operation and lost their mechanical durability. In order to determine the reasons of anchors’ degradation chemical composition of the elements was determined with the use of a spark spectrometer SPECTROLAB and sample morphology was investigated with JEOL JSM-6610LV scanning microscope equipped with LaB6 cathode.

Modern Power Engineering in the Light of the New Physical Representations and Technical Realizations. – A brief review

The perspective hypothesizes and elaborations represented in the special science literature and directed on the search of the new sources which are based on the physical principles of the energy extraction from the surrounding space are illuminated in the brief review. The so named “without-fuel” generators as the convertors of the different views of energy of the ether are described. Their elaboration becomes the more and more perspective business for solution of the modern energy problems. Their technical projects are passing to the state of the industrial production. According to the physical signs of the principle effectiveness, heat generators, magnetic dynamic convertors, convertors of gravitational energy and, finally, electrodynamics alternators are distinguished among them. In comparison with heat generators, the class of alternators using permanent magnets is more numerous and diverse. Convertors of gravitational energy are, as a rule, perpetuum mobiles containing structural components in which falling vertically downward weights or water are rotating the wheel, producing useful work. The selected group of the without-fuel generators is the electrodynamics alternators, working as convertors of the electromagnetic energy from the ether of the surrounding space. The most interesting example of electrodynamics alternators is the transformer Tesla known to a wide range of specialists. Its distinctive feature is an unusually high energy conversion coefficient (k>1000), much higher than the transformation ratio due to the inductive coupling between its windings. In conclusion, based on a comparison of analogs, a hypothesis on resonant phenomena as keys of access to ether energy in the surrounding space is formulated.

Моделирование режимов работы сетевой ветроэнергетической установки с синхронным генератором на постоянных магнитах

Windmills (WMs) equipped with permanent magnet synchronous generators (PMSGs) are widely used in modern wind power engineering applications. A grid WM equipped with a PMSG uses power converters for converting all electric power generated in the entire variation ranges of wind velocity and generator rotation frequency. The power converter connected on the generator side controls the generator’s active power supplied to the grid by means of the maximal power point tracing (MPPT) algorithm, and the power converter connected on the grid side controls the DC voltage and reactive power. For analyzing and studying the operation modes of a grid WM equipped with a PMSG, and for estimating the possibilities of controlling the generator rotation frequency under the conditions of variable wind velocity and generator rotation frequency with the optimal level of power supplied to the grid, all electric power components of the WM are modeled on a computer using available and newly developed systems in the MATLAB environment. The developed control algorithms implement control of the generator stator current zero direct component for monitoring the power converter connected to the generator, control of wind wheel blades position, and oriented control with respect to the grid voltage phasor for monitoring the power converter connected to the grid. The modeling results have shown that the model of the considered WM equipped with a PMSG developed in the MATLAB environment is able to perform full-scale power conversion from 0.068 p.u. to 0.985 p.u. with an average error of 2.58% with the wind velocity varying from its initial value equal to 5 m/s to the nominal value equal to 12 m/s and makes it possible to control the generator rotation frequency in the full range from 0.409 p.u. to 0.995p.u. with a percentage error of 0.91%. Thus, the model of the considered WM equipped with a PMSG developed in the MATLAB environment is adequate and can be used for reliably modeling the operation modes of a WM equipped with a PMSG.

Virtual power plants - types and development opportunities

Modern power engineering meets new challenges. With the development of new energy production and storage technologies, creates new demands for energy services. To support this development, it is necessary to implement new teleinformatic systems that will allow for resource management. Such systems are called Virtual Power Plants (VPP). There are many definitions of this type of solutions due to the very wide range of possible applications. VPPs can be developed by many types of entities, e.g. distribution system operators, electricity generators, energy clusters. The ability to build a system based on modules allows you to customize the system to user’s needs. An opportunity for the development of VPP will be a package “Clean energy for all Europeans” (so called “Winter package”) that introduces regulations that allow for the development of renewable energy sources, including prosumers, and enables an active participation in the energy market for energy consumers. In addition, more stringent requirements for balancing production and energy consumption are introduced, requiring greater balancing accuracy.

РОЗВИТОК ВУГІЛЬНОЇ ПРОМИСЛОВОСТІ В СУЧАСНИХ УМОВАХ

Технологічні революції є особливими моментами парадигмальних зрушень, коли старі технологічні уклади ще необхідні, але вони відходять, а нове вже проявилось, але ще не дістало належну підтримку бізнесу. У сучасних умовах економічні проблеми шахтного способу видобування вугілля збігаються з посиленнями вимог до забезпечення сталого розвитку людства, що веде до "згортання" галузі під натиском енергетики на відновлюваних джерелах.Починаючи з 1990-х років нами просувається ідея впровадження у вугільній промисловості економіко-організаційних гетерархій на зразок індустріальних парків, наприклад, схема корпоративної розробки шахтного поля, за якою приватна фірма на державній шахті веде розробку власного відводу, а державне підприємство надає фірмі платні послуги з підйому, транспортування, вентиляції, водовідливу, енергетичного забезпечення, санітарно-гігієнічного обслуговування персоналу. Це зумовило мету статті – обгрунтувати доцільність гетерархій у вугільній промисловості в умовах сучасної промислової революції. Дослідження методами наукової абстракції, аналізу і синтезу приводить до нетривіального рішення стосовно комплексного охоплення галузей, що з'являються і розвиваються. Таким, наприклад, є створення на шахтах індустріальних парків з акумулюванням енергії, які необхідні для функціонування енергетики на відновлюваних джерелах. Ці парки мають стати своєрідним "парашутом" для вугільної галузі, яка в нинішніх умовах занепадає, і «бустером» для найсучаснішої енергетики. Кластери енергетичних парків як енергетичні хаби в старопромислових шахтарських регіонах дають можливість диверсифікувати діяльність вугільних підприємств і вирішити комплекс економічних і соціальних проблем.

Applying enrichment capacities for multiple recycling of LWR uranium

The use of fissionable materials accumulated during the open fuel cycle faces both challenges and opportunities for modern nuclear power engineering. A growing disproportion between the production and consumption of natural uranium draws attention to the problem of used nuclear fuel. The paper examines the current situation in the field of reuse (single or multiple) of reprocessed uranium (recovered from spent nuclear fuel), which is used for the production of low-enriched fuel (LEU) to fuel the fleet of light water reactors (LWR). The world experience in handling this material has been analysed. This study also gives an overview of the currently proposed methods for enriching the 235U content in reprocessed uranium to the required level by means of gas centrifugation process, while simultaneously meeting the limitations on the presence of 232,234,236U in commercial LEU. Savings of natural uranium was estimated for repeated recycling of VVER spent fuel. It was supposed that re-enrichment of reprocessed fuel would be done by arranging the most promising for such purposes cascade schemes. The obtained results can be used as a basis for further scientific, technical, and feasibility studies on the large-scale utilization of reusable materials in the different fuel cycles of LWR.