Efficiency Of Power Unit Research Articles

Thermodynamic Analysis and Optimization of Binary CO2-Organic Rankine Power Cycles for Small Modular Reactors

Small nuclear power plants are a promising direction of research for the development of carbon-free energy in isolated power systems and in remote regions with undeveloped infrastructure. Improving the efficiency of power units integrated with small modular reactors will improve the prospects for the commercialization of such projects. Power cycles based on supercritical carbon dioxide are an effective solution for nuclear power plants that use reactor facilities with an initial coolant temperature above 550 °C. However, the presence of low temperature rejected heat sources in closed Bryton cycles indicates a potential for energy saving. This paper presents a comprehensive thermodynamic analysis of the integration of an additional low-temperature organic Rankine cycle for heat recovery to supercritical carbon dioxide cycles. A scheme for sequential heat recovery from several sources in S-CO2 cycles is proposed. It was found that the use of R134a improved the power of the low-temperature circuit. It was revealed that in the S-CO2 Brayton cycle with a recuperator, the ORC add-on increased the net efficiency by an average of 2.98%, and in the recompression cycle by 1.7–2.2%. With sequential heat recovery in the recuperative cycle from the intercooling of the compressor and the main cooler, the increase in efficiency from the ORC superstructure will be 1.8%.

Gas turbine operating as part of a thermal power plant with hydrogen storages

Over the past few years, much attention has been paid to hydrogen energy. The development of hydrogen technologies leads to a reduction in the cost of both the hydrogen fuel itself and hydrogen systems, which leads to a wider use of this type of fuel in various branches of the fuel and energy complex. At the moment, the primary task is to increase the efficiency of combined cycle power units, reduce wear and tear of equipment during peak electricity consumption, reliable backup of energy supply, and reduce harmful emissions during the generation of heat and electricity. One of the modern methods for implementing these challenges is the use of energy storage devices. A new solution to this problem can be the introduction of hydrogen storage in the cycle of a thermal power plant. The article considers the modernization of a combined-cycle power unit with a gas turbine PG6111FA manufactured by « General Electric» with a rated power of 80 MW, a waste heat steam boiler manufactured by JSC « EnergoMashinostroitelny Alliance», and a steam turbine KT-33/36–7.5/0.12. During periods of night unloading, the effective efficiency of the power unit drops, so it is necessary not to unload the equipment, but to turn on the electrolyzers for the production of hydrogen fuel for further use in hydrogen fuel cells. The operating time of the hydrogen system with an electrolyzer is not limited in time, the operation of the electrolyzer takes place during night unloading periods (from 4 to 7 h a day), while the hydrogen storage works constantly, in this mode of operation, the service life is about 15 years, for stable operation it is necessary hydrogen fuel and periodic maintenance. An important component of the hydrogen system is a hydrogen battery with minimal storage losses, in contrast to traditionally installed thermal storage. Studies of the use of hydrogen storage in the circuits of thermal power plants have shown their effectiveness, including their implementation allows you to increase the efficiency, reduce the cost of own needs of the power plant, reduce emissions in the production of electricity, a leveled load schedule allows you to increase the life of the gas turbine, as the turbine works in basic mode. The use of accumulators in thermal power plants increases the competitiveness among traditional energy generation systems.

CO2 Compression and Dehydration for Transport and Geological Storage

Observation of the greenhouse effect prompts the consideration of every possibility of reducing anthropogenic carbon dioxide emissions. One of the key methods that has been the subject of much research is Carbon Dioxide Capture and Storage. The purpose of this study was to investigate the main technologies of CO2 capture, separation, and dehydration as well as methods of its transport and methodology of selecting a suitable geological storage site. An installation of dehydration and compression of carbon dioxide captured after the post-combustion was designed at a temperature of 35 °C, a pressure of 1.51 bar, and a mass flow rate of 2.449 million tons/year, assuming that the geological storage site is located at 30 km from the capture place. For the dehydration process, a multistage compression and cooling system were applied, combined with a triethylene glycol (TEG) dehydration unit. The mass flow rate of TEG was selected as 0.5 kg/s. H2O out of the TEG unit was 26.6 ppm. The amount of energy required to compress the gas was minimized by adopting a maximum post-compression gas temperature of 95 °C for each cycle, thereby reducing plant operating costs. The total power demand was 7047 kW, 15,990 kW, and 24,471 kW, and the total received heat input was 13,880.76 kW, 31,620.07 kW, and 47,035.66 kW for 25%, 60%, and 100% plant load, respectively. The use of more compressors reduces the gas temperature downstream through successive compression stages. It also decreases the total amount of energy required to power the entire plant and the amount of heat that must be collected during the gas stream cooling process. The integration of CO2 compression and cooling system to recover heat and increase the efficiency of power units should be considered.

Deep-learning optimization and environmental assessment of nanomaterial's boosted hydrogen and power generation system combined with SOFC

Renewable energy sources are unquestionably required, given that the world's energy consumption is anticipated to increase significantly in the next decades. Besides, fuel cell converts chemical energy directly into electricity, making it the most efficient and environmentally friendly power source. This study examines the viability of producing electricity using a supercritical CO2 cycle, a methane digester, and a gas turbine. Applying the principles of exergetic balance, mass, energy conservation, and component-specific exergetic balance to each part of the power unit allow for a simulation of the power unit's efficiency. Furthermore, a parametric analysis is performed to establish how the relevant factors will affect the unit's functioning. The optimization algorithms are generated with the help of deep learning methods. It was found that the ratio of the compressor's pressure to the current density was the most crucial element in determining output power. Nanoparticles are used in fuel cells to enhance heat transfer and, thus, the generated power. Through optimization, one might find a product that is both the most cost-effective and energy-efficient option available. Artificial neural networks may be used as a mediator to help expedite the process of reaching optimum performance across several criteria. The optimal settings for the planned power plant are now being determined by studying the correlation between design factors and objective functions. Therefore, the second law's efficiency at its sweet spot was calculated at 61.8%. In the end, the system at its optimum point was found to have an exergo-environmental index of 0.436.

A Small Capacity Methane-Hydrogen Blend Fueled Gas Turbine

Nowadays the environmental problem is of issue for many scientists around the world. This is stemming from climate changes caused by greenhouse gas emissions (the industrial sector accounts for 50% of them). Therefore, urgent measures have to be taken to reduce the emissions of these gases significantly. In this connection, we are witnessing a worldwide trend toward predominant use of renewable energy sources, with the hydrogen energy being the most significant one of them. The aim of the work was to study the effect an addition of hydrogen to methane as fuel has on the thermal characteristics of a 100 kWe micro gas turbine unit and on the geometrical dimensions of the fuel admission device at constant values of the volumetric flow rates of air supplied and flue combustion gases generated in the same installation. The study, which was carried out using the EPSILON computer program, has shown that the addition of hydrogen to methane leads to an increase in the volumetric fuel flowrate and, hence, generates the need to increase the fuel admission device cross-section area. An increase in the percentage content of hydrogen leads to a decrease of temperatures upstream of the turbine by no more than 12°C. If methane is completely replaced by hydrogen, the power unit efficiency decreases by only 1%. Thus, the thermal characteristics of the micro gas turbine unit under study do not change significantly; however, the design of the fuel injection device has to be modified.

Principal Modernization Solutions for a 300 MW Power Unit to be Converted to Operate at Ultra-Supercritical Steam Parameters

This paper analyses the state of power engineering in Ukraine and the main trends in the development of the world market in the field of converting high-capacity powerful power units of thermal power plants into ultra-supercritical (USC) ones. It is shown that the energy sector of Ukraine requires special attention and the introduction of new modern technical solutions. Worldwide trends indicate that the emphasis is now on increasing the steam parameters before a turbine to ultra-supercritical ones. This allows one both to increase the efficiency of power units and to reduce thermal emissions, fighting the global environmental problem of climate warming. The implementation of this approach is proposed taking into account the realities of the Ukrainian economy and the available technical capabilities of the power engineering industry. This paper presents the results of variational computational studies of the thermal scheme of the 300 MW power unit of the K-300-23.5 turbine to be converted into a USC one. The problem was solved under the condition of maximizing the preservation of the thermal scheme, increasing the efficiency of the power unit and minimizing capital investments during the modernization of the turbine. It was chosen to preserve the regeneration system, as well as the medium-pressure (MP) and low-pressure (LP) cylinders. Considered and calculated were variants with the addition to the existing turbine of a USC cylinder and the creation of a new high-pressure cylinder (HPC) with insignificant changes in its overall characteristics. The results of computational studies showed that the most rational variant for modernizing the 300 MW turbine plant is the creation of a new HPC designed for operation at USC steam parameters as well as the addition to the IPC of a new cylinder with the purpose of increasing the reheat steam parameters while preserving the regeneration system.

An energy method for computing the use of fossil fuel energy

An energy method for computing the use of fossil fuel energy has been considered in the article. On the world market, the fuel price depends on supply and demand and involves no energy costs for fuel production. An energy analysis of economic activity was suggested by Charles Hall, an American scientist, who introduced a notion of Energy Returned on Energy Invested, as a ratio between returned and invested energy, into scientific discourse. No account has been taken of invested energy depreciation in this method. All losses are fully incorporated, when the ratio between beneficially used energy in all process flow chains from fuel deposit exploration to energy utilisation, and the considered amount of natural fuel primary energy is taken as the coefficient of beneficial primary energy use (CBPEU). When CBPEU is determined, allowance is made for all potential energy losses; the depreciation degree of energy, contained in the fuel, from its deposit to a consumer, is defined. When energy of renewable sources is utilised, a coefficient of renewable sources energy conversion, defined as the ratio between energy delivered by a power unit throughout the entire operation period, and invested energy taking into account CBPEU over the same period, will represent an objective criterion of power unit efficiency.

РАСЧЕТ ВЛИЯНИЯ ТЕМПЕРАТУРНЫХ ПОЛЕЙ НА КАЧЕСТВО ПОЛУЧАЕМЫХ КОМПОЗИЦИОННЫХ ПОКРЫТИЙ

Increased attention is currently being paid to improving the reliability and efficiency of power units. The use of materials with special coatings that have the necessary set of characteristics allows you to increase the service life of the restored components and assemblies. One of the ways to obtain such coatings is by plasma spraying. (Research purpose) The research purpose is in predicting the performance indicators of composite coatings using a mathematical tool that adequately describes the process of coating build-up during plasma spraying. (Materials and methods) Authors used a universal UPU-3 installation with modifications to produce coatings, which allowed controlling the heat transfer process with high accuracy. Authors used small-sized cooling water temperature sensors located at the connection point of the current-carrying hoses to the sprayer to record the enthalpy of the jet. During the coating process, the restored part remained stationary, and a plasma torch carried out the movement along the sprayed part. The advantage of this method is the independence of the mass of the recovered parts from the drive power of the plasma torch. (Results and discussion) The article presents the mathematical model, which is a system of nonlinear partial differential equations describing the process of heat transfer during the application of plasma-sputtered coatings, taking into account the initial conditions determined using the UPU-3 installation. To solve the presented system of nonlinear differential equations, the method of perturbation theory with the use of thermal potentials is used. (Conclusions) The article proposes the ways to solve the problem of heat transfer during the application of plasma-coated coatings, which allow us to predict the performance indicators of the restored parts.

Estimation of the efficiency of combining a npp with a hydrogen facility under conditions of safe use of hydrogen in a steam turbine cycle

THE PURPOSE. System efficiency and competitiveness assess of a new scheme for combining a nuclear power plant with a hydrogen complex based on additional heating of feed water and superheating of live steam in front of the high-pressure cylinder of a steam turbine. METHODS. Basic laws of thermodynamics were applied when developing and substantiating a new scheme for combining a nuclear power plants (NPP) with a hydrogen facility; theoretical regularities were applied of heat engineering; basic regularity were applied of fatigue wear of power equipment and assessment of its working resourse; basic regularities were applied for the assessment of operating costs and net present value (NPV). RESULTS. A new scheme is presented of the combination of a nuclear power plant with a hydrogen facility and a description of its operating principle on the example of a two-circuit nuclear power plant with a VVER-1000 reactor and a C-1000-60 / 1500 turbine. The data are presented on an increase in the productivity of steam generators at nuclear power plants with additional heating of feed water in the range of 235-250 ° C from its nominal value of 230 ° C. The temperature was estimated of live steam superheat depending on the temperature of the additional heating of the feed water. The results are presented of the calculation of the generated peak power by the power unit and the efficiency of conversion of the night off-peak power of the NPP into peak power, as well as the efficiency of the power unit of the NPP depending on the temperature of additional heating of the feed water. Main regularities are given for taking into account the fatigue wear of the main equipment of the hydrogen facility, including the rotor of the NPP turbine in the conditions of the stress-cyclic operation. The results are presented of assessing the cost of peak electricity NPP in combination with a hydrogen facility in comparison with a pumped storage power plant (PSPP) both for the current period and for the future until 2035. CONCLUSION. Hydrogen facility efficiency and competitiveness depends significantly on the intensity of the use of the main equipment in the conditions of the intense-cyclic operation. The hydrogen facility will competitiveness noticeably increase in comparison with the PSPP in the future. Efficiency of the NPP power unit and NPV is highest when the feed water is heated to 235 ° C and superheating of live steam in front of the high-pressure cylinder of the C-1000-60/1500 turbine up to 470°C.The hydrogen facility competes with the PSPP with her specific capital investment at the level of 660 USD / kW, provided that the boosting capabilities of the turbine are used with live steam overheating at 300 ° C and additional heating of feed water to 235°C on the current period. The PSPP does not compete with the hydrogen facility both for the current period and in the future with her specific capital investment of $ 1,500 / kW and above.

Mathematical modelling of the CHP plant-10 power unit No 5 of “Baikal Energy Company” LLC to assess the efficiency of its modernisation

The work aims to study the effect of changes in the drain scheme of the low-pressure regeneration on the energy and economic efficiency of the CHP plant-10 power unit No 5 of “Baikal Energy Company” LLC. In this study, we used a mathematical model of the power unit adjusted to the measurements results. The mathematical modelling of the power unit was performed using the “Computer-assisted programming system” application package. The created matematical model of the heat and power plant was tailored to the current state of the study object according to the three-stage identification procedure of the mathematical model parameters. We proposed a cycle arrangement under which three streams of the low-pressure drainages were redirected to the pump suction of the low-pressure heater. The improved mathematical model of the power unit allows the calculation of the parameters of both the existing and proposed cycle arrangements. According to the calculations, the temperature difference between the main condensate after the low-pressure heater 1 and the investigated drains after mixing is minimal and amounts to 3.2 °C. The suggested modernisation increases the energy efficiency of the power unit by 0.007% under the nominal operating conditions of the existing and proposed thermal circuit. In addition, the specific standard fuel consumption for electric generation is reduced by 0.052 g.s.s.f./kWh. The operating costs to implement the proposed engineering solutions amounted to 34,191 roubles. Considering the annual power plant extensive consumption factor, the payback period of the proposed modernisation will be 5.5 months. The savings for the first operation year are estimated at 18,423 roubles, based on the rate of return and depreciation expenses. The proposed approach combines mathematical modelling of operating power plants with a technique of increasing the efficiency of technical decision-making. The proposed versatile approach can be used for the modernisation of CHPs and other plants.

Optimization of the cooling water mass flow rate under variable load of a power unit

• Optimization of the cooling water mass flow rate for a power unit was performed. • The cooling water mass flow rate should be reduced for load below 60% of rated power. • The power unit model in off-design conditions was developed in Ebsilon software. As the contribution of renewable energy sources in the energy balance is increasing, traditional thermal power units have to be more flexible over a full and thus extended range of load conditions, among other requirements. Furthermore, the efficiency of power units should not significantly decrease under lower load conditions which will often occur. The paper analyzes the process of determining the cooling water mass flow rate under the power unit load varying between 100% and 40% with the aim of achieving the maximum efficiency and power output. A mathematical model of a 225-MW power unit was developed using Ebsilon software and validated based on measurement data. The efficiency characteristics of the boiler, turbine and cooling water pump in off-design conditions as a function of load were entered in Ebsilon. As part of the calculations, the optimal cooling water mass flow rates were determined. The analysis shows that reducing the cooling water mass flow rate may seem reasonable in the case of power units operating at less than 60% load. Assuming that the power unit operates under 40% load for 1000 h per annum, if the cooling water flow rate is reduced from the nominal value down to the optimal one, the 225-MW power unit would produce an additional net power output of about 137 MWh.

Research based on mathematical modeling of CHP-10 power unit No 5 “Baikal Energy Company” LLC to assess the efficiency of its modernization

The work aims to study the effect of changes in the drain scheme of the low-pressure regeneration on the energy and economic efficiency of the CHP plant-10 power unit No 5 of “Baikal Energy Company” LLC. In this study, we used a mathematical model of the power unit adjusted to the measurements results. The mathematical modelling of the power unit was performed using the “Computer-assisted programming system” application package. The created mathematical model of the heat and power plant was tailored to the current state of the study object according to the threestage identification procedure of the mathematical model parameters. We proposed a cycle arrangement under which three streams of the low-pressure drainages were redirected to the pump suction of the low-pressure heater. The improved mathematical model of the power unit allows the calculation of the parameters of both the existing and proposed cycle arrangements. According to the calculations, the temperature difference between the main condensate after the low-pressure heater 1 and the investigated drains after mixing is minimal and amounts to 3.2 °C. The suggested modernisation increases the energy efficiency of the power unit by 0.007% under the nominal operating conditions of the existing and proposed thermal circuit. In addition, the specific standard fuel consumption for electric generation is reduced by 0.052 gram of conventional fuel / kW·h. The operating costs to implement the proposed engineering solutions amounted to 34191 roubles. Considering the annual power plant extensive consumption factor, the payback period of the proposed modernisation will be 5.5 months. The savings for the first operation year are estimated at 18423 roubles, based on the rate of return and depreciation expenses. The proposed approach combines mathematical modelling of operating power plants with a technique of increasing the efficiency of technical decision-making. The proposed versatile approach can be used for the modernisation of CHPs and other plants.

Model of a neural network adaptive system for a digital control loop of an electric drive

The problem of increasing the efficiency of power units of autonomous electric transport vehicles is considered. The task of creating a promising power system control device has been singled out. It is determined that in creating such devices, significant results can be obtained by using an intelligent module in the control loop of the electric drive. Goal. It is necessary to develop a power plant model with intelligent control, allowing to obtain data sets about currents, voltages and engine speeds in different modes of operation. The architecture of an intelligent control device, a PID controller based on a neural network, has been proposed; it has been proposed to exclude rotor angular velocity sensors from the classical feedback loop. The type and architecture of the neural network is defined. In the software environment MatLab the model of neuroemulator of the engine for formation of a training sample of a neural network by a method of Levenberg – Marquardt is developed. The trained neural network is implemented in the developed model of the electric motor control loop. The results of simulation of the intelligent control device showed a good convergence of the output influences generated by the neuroemulator with the actual parameters of the electric motor.

Витрати палива технологій теплової енергетики в маневрених режимах

A characteristic feature of the present day development of power engineering lies in the increase in the unevenness of power systems schedules. The structure of generating powers of Ukrainian energy engineering is overloaded with basic powers and characterized by a sharp deficit of maneuvering wanes. To cover the uneven load of the power system during the operation of existing and construction of new power plants, it is necessary to take into account the possibility of their operation under maneuvering modes. This paper determines the influence of work of power plants i under maneuvering modes on the specific consumption of conditional fuel on the released electric energy at working on gas or coal fuel. Fuel consumption for starting of a unit depends on its type and downtime in reserve. The use of steam–and–gas facilities and gas turbines helps to enhance the maneuverability of power plants. Alternative options for the development of thermal energy are the introduction of gas–piston power plants and power units with fluidized–bed boilers. We present formulas for the calculations of fuel consumption on by power units for start–ups and specific consumptions depending on the load and degree of their involvement to regulating loads for different thermal energy technologies: steam–turbine condensation and district heating power units; steam–and–gas and gas turbine plants; gas piston installations; power units with fluidized bed boilers. For enhancing the maneuverability of power plants, working on fossil fuels, their modernization and renewal of software are necessary. Quantitative assessment of the efficiency of power units and separate power plants during their operation under variable modes is important for forecasting the structure of generating capacities of power systems, the need to introduce peak and semi–peak capacities, the choice of the most profitable composition of operating equipment at different schedules of electrical loads Keywords: thermal power, power unit, maneuverable mode, electrical load, specific fuel consumption

Reliability of integrated parameters of operational efficiency of TPP power units

A new method and an algorithm of ensuring the uniformity of normalized samples of technical and economic parameters of power units of thermal power plants are presented. Uniformity and normalization are obligatory conditions at estimation of integrated parameters characterizing the efficiency of power units. The method is based on the fiducial approach. Boundary values of fiducial interval are traditionally calculated based on the statistical function of distribution and a set significance value, i.e. are calculated, in fact, "mechanically". As the "mechanical" approach is appropriate for homogeneous statistical data, whereas technical and economic parameters are multivariate data, application of this approach to the statistical function of fiducial distribution is associated with a high risk of an erroneous decision. The set of possible realizations of actual values of technical and economic parameters includes realizations caused by "gross" mistakes at data input in automated systems or at manual performance of individual calculations. Quite often, unconventional realizations are observed, e. g., in case of low-load operation for 10 days of a month. These data form boundary intervals that the authors refer to as “boundins” (or prigrins in Russian). Automated search and removal of boundins provides reliability of comparison and ranking of integrated parameters. It is shown that rate of variation of boundins is considerably below the rate of variation of typical realizations of technical and economic parameters. This fact was the basis for recognition of boundins.

Study of change in 300 MW power unit efficiency operation under reduced loads

The article presents the results of the study of technical and economic parameters of power unit’s operation under reduced turbine generator loading, related to the night power dip and wear of power plant units. Changes in fuel consumption under reduced loading, change in power unit efficiency and change in main specific characteristics of the power unit were investigated. Conclusions on the 300 MW power unit’s operation modes under different turbo-generator loads were drawn based on the results of the calculations and investigations.

Designing a 3-D Model of Bodywork of a Vehicle with Low Coefficient of Drag and High Downforce

To extract the maximum performance out of the engine and transmission unit the bodywork of the vehicle should be as streamed lined as possible. But at the same time down force must also be accounted for since many accidents take place at high speeds due to driver losing control. While drag reduction is important, the generation of downforce is also important as it plays a major role in determining the handling characteristics of the vehicle. The project is aimed at developing the bodywork of a high performance vehicle to induce the lowest drag possible along with high downforce by creating a diffuser and smoothening the underbody of the vehicle. The project will discuss the influence of shape of the bodywork in mainly underbody area (when using a diffuser) as it will increase the downforce of the vehicle without creating a lot of drag force as vehicles with underside whose engine and exhaust pipes and suspension arm exposed create a lot of flow separation which in turn increases drag and decreases downforce. The diffuser utilizes the ground effect produced due to Bernoulli’s principle in a vehicle to produce negative lift or downforce while the smooth underbody ensures lesser flow separations as they contribute towards vehicles instability at high speeds and lower efficiency of power unit. The smooth underbody along with teardrop driver and engine canopy reduce flow separation in areas of vehicle where it is common to experience it, helps in reaching Carbon emission to be reduced. The method of CFD simulation in ANSYS-FLUENT will be used in to conduct tests and obtain the results since accessibility to make physical model of vehicle and wind tunnel was not present and the other reason being the negligible error between the simulation and physical tests.

Structural-and-Parametric Optimization of Automatic Control System for Power Units of 300 MW in Wide Range of Load Variations

The structural-parametric optimization of the automatic control system for power units (ACSPU) of 300 MW of Lukoml’skaya GRES (Lukoml Local Condensing Power Plant) in the mode of both the permanent and the variable superheated steam pressure upstream of the turbine is under consideration. During 1974–1979, eight units of the Lukoml’skaya GRES implemented the ACSPU with a leading boiler power control. At the moment, these systems no longer meet all the frequency control quality requirements. In 2016, the daily schedule of electric loads of the Belarusian power system was as follows: the basic part of the schedule of electric loads was covered by combined heat and power plants (CHP) and by mini-CHP (which are the least maneuverable of the power plants), the semi-peak part of it–by local condensing power plants (Lukoml’skaya GRES and Berezovskaya GRES), the peak part–by import electric energy from neighboring power systems. However, this year the first unit of the Belorussian NPP will be put into operation, while the second one–in 2020. After the launch of the Belorussian NPP, it will cover basic part of load curve; CPPs will cover the semi-peak part, while the peak part of load curve will be covered by local condensing power plants. Correspondingly, due to the alteration of the structure of daily schedule of electric loads of the Belarusian power system, it is necessary to improve the efficiency of power units of Lukoml’skaya GRES as well as of the entire Lukoml’skaya GRES in general. This can be achieved with the help of the method of parametric optimization of the typical ACSPU proposed in the present paper. As a result, the quality of control of power and pressure upstream of the turbine will be improved; the flow of fuel will be reduced, as well as the turbine regulation valve displacement; environmental performance of entire power plant will be improved, too. The proposed technique has been confirmed by the results of computer simulation of transient processes in the automatic control system under external and internal disturbances.

Feasible Ratio Determination of the Thermal Oil Equipment Waste-Heat Recovery

The applicability of the thermal oil equipment flue gases thermal energy recovery relates to heating the air amount required for the fuel burning, and technical and economic feasibility. The paper objective is to define the regenerative system air heating temperature optimal value and to study the temperature impact on the heat power unit efficiency. The problem solution is air heating temperature optimal value. calculation algorithm. The methods of the complex heat exchange mathematical modelling, optimization problem numerical solution, non-linear programming, and feasibility study were used in the research carried out. The study results of the temperature influence of heating the air required for fuel combustion on the thermal oil equipment technical and economic efficiency are presented.

Potential and methods for increasing the flexibility and efficiency of the lignite fired power unit, using integrated lignite drying

Present increase in the flexibility of coal power plants is a very important and complicated task. The paper discusses the problem of improving the flexibility and efficiency of the power unit on the example of a brown coal-fired unit including the option of low-temperature pre-drying of lignite. Drying technologies using low-temperature heat sources are analysed. Depending on the coal drying method, an up to 5% increase in power unit efficiency can be achieved. The possible actual increase in the efficiency of a specific power unit will result from the individual features and local conditions of the particular power plant. However, for hybrid systems with thermal energy accumulation system, the increase in efficiency depends on the selection of the energy charging system, type of accumulation system and working temperature range. In the authors’ opinion, the implementation of a drying technology for the needs of co-firing in power units should be based on rather the utilization of the internal heat sources of the given power unit with the possible additional use of “waste” or renewable energy sources. The proposed solutions are evaluated from the technical point of view and the expected increase in power unit efficiency is determined.