Steam Turbine Plant Research Articles

Effectiveness of the joint scheme of steam-power and combined-cycle power units using the example of the Nevinnomyssk State Regional Thermal Power Plant

We attempt to solve the problem of displacing high-temperature steam bleeding in a steam turbine plant at the first regenerative heater after intermediate overheating. This can be achieved when the thermal power plant contains heterogeneous equipment, in particular, a steam turbine and combined cycle power units. The authors proposed an energy-efficient scheme for the joint operation of steam turbine unit and steam-turbine part of a combined cycle plant with the displacement of high-temperature steam onto the high-pressure feed heater (HPFH 2) using the dry steam from the medium-pressure drum of the waste boiler in order to increase the upper limit of the power plant’s control range. For this research, Nevinnomyssk TPP was selected as one of the main energy facilities of the Unified Energy System of Southern Russia. We studied the joint operation of the steam turbine unit K-160-130 and the combined cycle plant CCP-410 manufactured by Siemens, Germany. We developed the methodology and calculated the energy efficiency of the new power plant operation scheme. According to the calculation results, the total increase in power amounted to 6.03 MW, while there was an increase in electrical gross efficiency by 0.64%. An assessment of the economic effect of the applied solution for the conditions of the Nevinnomyssk TPP demonstrated that the annual increase in net profit will amount to 14.47 million rubles, and the payback period of investments is 4.2 months.

Optimal Plate Heat Exchangers of Power Generation Systems

Plate heat exchangers are an effective type of heat exchange equipment and can be used in many power plants. The article analyzes the use of corrugated plate heat exchangers in a number of installations. Their optimization was done according to the economic criterion of optimality, taking into account capital investments and operating costs. The analysis of the plate heat exchangers uses as oil coolers (a number of loads with oil mass flow rates 10….250 kg/s) and water heaters (heat power 100…2000 kW) of steam turbine plants. It has been established that plate oil coolers are more economical than shell-and-tube ones. Also, the anti-icing system plate air heaters of gas turbine plants with a power of 1 to 20 MW considered. The air for the anti-icing system was taken after the compressor and was additionally heated by exhaust gases. It has been established that it is necessary to install an additional flue gas smoke exhauster for using plate heat exchangers. Air must be extracted after the compressor, otherwise, low air density leads to high hydraulic losses, which makes it impossible to use plate heaters. Optimum air velocities are in the range of 0.4…0.6 m/s, flue gas velocities are 4…6 m/s. The use of standard plate heat exchangers with corrugated plates is impractical for GTU powers above 5 MW. Optimization of plate regenerators of supercritical CO2 cycles with recompression for powers from 1 to 15 MW has been done. Optimum velocities of hot CO2 are about 0.8 m/s, cold ones 0.3…0.5 m/s. The optimal sizes of plate heat exchangers are recommended for all of the above applications.

Thermo-statistical study of sustainable refrigeration system for stack flow heat recovery of combined gas turbine-steam turbine power generation

Abstract The major part of input heat of power plant is lost during the exhaust flow process and this flue gas has tremendous potential for heat recovery and cooling generation. The employment of LiBr-H2O based eco- friendly and less energy consumption vapour absorption refrigeration system (VARS) is integrated with stack flow unit of combined gas turbine and steam turbine (GT-ST) plant. If thestack flow temperature is maintained about 200–250 0C, the projected VARS is suitable for the generation of efficient cooling effect. The main highlights of this research work have been concluded in terms of exergy losses in components, exergetic& overall efficiency of combined plant. The maximum irreversibility has been found in combustion chamber (CC) of GT system and exhaust flow ofST system as 66.8% and 13.4% respectively. The effect of GT plant efficiency influences the overall performance. The proposed VARS performance coefficient estimated as 0.708 with 05 ton of refrigeration effect which is valuable achievement for space cooling purpose for plant infrastructure and efficiently it can replace high grade energy consumption vapour compression refrigeration system (VCRS) type air conditioning system. This eminence cooling technology of VARS system can save 10,440 USD yearly in terms of energy and carbon emission, and able to map the de-carbonized economy infrastructure. The methane fuel gas has found remarkable performance at 8 bar of compressor pressure and 900 0C GT inlet temperature (GTIT) of operating condition with all set of operating factors by using MLR method of DOE. The determination coefficient (R2) is computed as 0.991 which gives minimum deviation between actual and predicted results.

Subcritical Thermodynamic Cycles with Organic Medium and Isothermal Expansion

The efficiencies of the Organic Rankine Cycle (ORC) are not very high and only very seldom do they exceed 20%. The increase and optimization of initial parameters and certain modifications of the thermodynamic cycle make it possible to overcome these drawbacks. A new modified cycle has been described and analyzed in detail in the paper. Similarly to the Ericsson cycle for gas turbines, isothermal expansion in the turbine is suggested for the power plant with organic media. The new cycle and the typical ORC power plants have the same block diagram. The only difference is that expansion in the proposed cycle occurs not adiabatically but as an isothermal process. The thermodynamic calculations have been carried out for 11 various fluids and 4 different cycles. The obtained results have clearly shown that cycles with isothermal expansion (isothermal turbines) are characterized by remarkably higher efficiency than typical power plants with adiabatic turbines. The increase in efficiency varies from 6 to 12 percent points for cycles with saturated live vapor and from 4 to 7 percent points for cycles with superheated live vapor. The performed analyses have shown that it is possible to achieve a very high efficiency (over 45%) of organic cycle, which is a very competitive value. In such cases the proposed power plants can achieve an efficiency which is higher than that of modern steam turbine plants with supercritical parameters.

Investigation of the Cooling of Water-Cooled and -Moderated Reactors Based on Electricity Generation Via Residual Heat in Emergency Situations with De-Energization

Safety enhancement of NPP power units with water-moderated and -cooled reactors on the basis of installation of additional multifunctional low-power steam-turbine generators is studied. It is shown that the parameters of the primary and secondary loops change as the VVER-1000 reactor is cooled via the use of the residual heat in the core to generate steam that serves as the working body for a low-power steam-turbine plant. Uninterrupted power supply for the NPP’s own needs is achieved on account of the fact that in normal and emergency regimes the low-power turbine unit supplies electricity to power consumers during cooldown of a reactor in an emergency situation with a blackout. It is shown for the example of 6 and 12 MW turbine units that the residual heat from one VVER-1000 reactor is sufficient to cool two such reactors for 72 h with de-energization of the NPP and depressurization of the primary loop in one of them.

Study of TGM-94 boiler with variable feed water temperature using a calculation model

The article substantiates the need to test performance capability and effectiveness of a steam boiler in the new conditions under any changes in the regenerative heating circuit of the feed water in a steam turbine plant. Such changes may include: the displacement of steam extractions onto high pressure feed water heaters by the sun, by heat from biomass or garbage burning, or by steam from third-party sources. For this purpose we have developed a mathematical model of the steam boiler TGM-94 from steam turbine installation K-150-130. The model was created with Boiler Designer program. Verification of the calculated and experimental data provided by Krasnodar TTP showed sufficient convergence in both the steam-water and gas paths. We observed differences in the following temperatures: feed water temperature after the first stage of the economizer, flue gases and air temperature at the inlet to the furnace. The maximum difference between calculation and experiment here is 6 °C. We studied the boiler operation at a variable load, but with a constant temperature of the feed water equal to the nominal value of 230 °C. It was shown that in order to work in this mode, and in order to maintain the superheat temperature of the primary and secondary steam, it is necessary to turn on the flue gas recirculation smoke exhausters. We studied the operation of the boiler at a reduced feed water temperature. It turned out that such work leads to a decrease in steam production, if we keep the fuel consumption unchanged. In the case of sustaining steam production, it is required to assess the temperature state of the heating surfaces additionally due to a significant increase in the superheat temperature of both the primary and secondary steam.

ВЫБОР ТИПА ГАЗОПОРШНЕВЫХ УСТАНОВОК ДЛЯ ТЕПЛО- И ГАЗОСНАБЖЕНИЯ В РОССИИ

In various sectors of the economy, including district heating systems in cities and settlements, steam turbine and gas turbine thermal power plants are mainly used. Their operation is based on cogeneration, which is the conversion of chemical fuel energy into electrical and thermal energy. At the same time, a significant part of the heat supply sources are still represented by heating boilers, which consume electricity for their own needs. In the gas industry, diesel engines are used as the drive for gas pumping plants. One of the factors hindering the organization of combined production of electric and thermal energy in heating boilers is the lack of production in Russia of gas-piston power plants with a capacity of more than 500 kW. The use of imported equipment for these purposes is usually not economically and technologically justified. According to the order of the Ministry of Industry and Trade of Russia dated 16.04.2019 No. 1327, the share of imports of gas piston and gas turbine units is planned to be reduced from 70% in 1918 to 25% in 2024. One of the promising directions of creating gas piston installations in Russia is justified: reproduction on a modern technological basis of two-stroke engines produced in the USSR of GD100 series gas piston engines that are still working at a number of facilities. The Russian government is considering converting mainline and shunting locomotives of railway transport to gas-powered fuel. One of the ways of increasing the efficiency of two-stroke engines is shown-in-cylinder mixing of gas with air with pre-chamber-flare spark ignition.

Advanced Turbine Cycles with Organic Media

Organic Rankine Cycle (ORC) power plants have become very popular and have found their applications in systems with renewable sources of energy. So far their overall efficiencies are not very impressive and only for the upper temperature of about 300 °C do they exceed 20%. A drawback of these cycles is the limitation of the cycle upper temperature due to the heat exchanger technology and the materials used. However, it is possible to overcome these difficulties by certain modifications of the thermodynamic cycles, a proper choice of the working medium and the optimization of cycle parameters. In the paper the problems of choosing the working medium and the question of higher temperature at the turbine inlet have been discussed. Different modifications of the schemas of the thermodynamic cycles have also been taken into account. The variants of power plants with regenerators, reheaters and heat exchangers have been considered. The proposed increase in temperature (in some cases up to 600 °C or higher) and innovative modifications of the thermodynamic cycles allow to obtain the power plant efficiency of above 50%. The modified cycles have been described in detail in the paper. The proposed cycles equipped with regenerators and reheaters can have the efficiency even slightly higher than classical steam turbine plants with a reheater and regenerators. Appropriate cycle and turbine calculations have been performed for the micro power plants of turbine output in the range of 10 kW–300 kW (up to several MW in some cases). The best arrangements achieved very high values of the overall cycle efficiency.

An Alternative Numerical Model for Investigating Three- Dimensional Steam Turbine Exhaust Hood

A proper design of exhaust hood geometry is very much essential in order to improve the overall efficiency of the steam turbine plant. The geometry of the non-axisymmetric exhaust hood makes the fluid flow at the exit of the steam turbine to be radially and circumferentially non-uniform. This work involves computational simulation of steam turbine asymmetric exhaust hood flows by incorporating the actuator-disc concept. The ANSYS FLUENT, finite volume based CFD solver is used for the present computational study. In the present simulation, the implementation of actuator disc boundary conditions with and without tip leakage is described in detail. The Actuator disc model approach exhibits a similar steam turbine exhaust hood flow asymmetry and static pressure recovery compared with the results reported in the literature, highlighting the applicability of the present model in coupling the rotor tip leakage jet with the steam turbine hood flow structure with less computational effort.

Координация настроек автоматических регуляторов паротурбинной установки распределенной генерации

Координация настроек автоматических регуляторов паротурбинной установки распределенной генерации

Энергетический баланс и показатели тепловой экономичности энергоблока атомной электрической станции

The Guidelines for drawing up a technical report on the effectiveness and thermal efficiency of nuclear power plant operation that have been developed at the All-Russian Research Institute for Nuclear Power Plants Operation (VNIIAES) contain a recommendation according to which the thermal power supplied to external consumers should be determined taking into account the heat transferred to the delivery water in the power plant's district heating installation network pumps. Similarly, the thermal power consumed for power generation should be determined taking into account the heat transferred to the primary circuit coolant and to the secondary circuit working fluid in the pumps installed in the NPP thermal process cycle circuit. The thermal energy transferred to the water in the NPP process circuit pumps is noticeably smaller than the electric energy (in the same units of measurement) supplied to the pump driving electric motors, and the total power consumed by the drive motors is less than the total electric power consumed for the power unit auxiliaries. The energy balances of an NPP power unit equipped with a VVER reactor and of its main process installations, namely, the nuclear steam supply system (NSSS) and the steam turbine plant (STP) are drawn up as applied to their operation in the steady-state mode. The obtained balances were used to derive formulas for calculating the thermal efficiency indicators: the gross and net electric efficiency values. In drawing up the energy balances separately for the NSSS and STP, their performance efficiency indicators were determined. The results of calculations using these formulas for a power unit equipped with a VVER-1000 reactor, the thermal process circuit of which incorporates only electric motors as pump drives, are taken as an example. The obtained results show that the additional heating of water in the pumps has a noticeable influence on the thermal efficiency indicators, a conclusion that seems to be of importance at the present stage of designing the thermal process circuits of NPP power units.

Comparative analysis of the Allam cycle and the cycle of compressorless combined cycle gas turbine unit

Nowadays, alternative thermodynamic cycles are actively studied. They allow to remove CO2, formed as a result of fuel combustion, from a cycle without significant energy costs. Calculations have shown that such cycles may meet or exceed the most advanced power plants in terms of heat efficiency. The Allam cycle is recognized as one of the best alternative cycles for the production of electricity. Nevertheless, a cycle of compressorless combined cycle gas turbine (CCGT) unit is seemed more promising for cogeneration of electricity and heat. A comparative analysis of the thermal efficiency of these two cycles was performed. Particular attention was paid to ensuring equal conditions for comparison. The cycle of compressorless CCGT unit was as close as possible to the Allam cycle due to the choice of parameters. The processes, in which the difference remained, were analysed. Thereafter, an analysis of how close the parameters, adopted for comparison, to optimal for the compressorless CCGT unit cycle was made. This analysis showed that these two cycles are quite close only for the production of electricity. The Allam cycle has some superiority but not indisputable. However, if cogeneration of electricity and heat is considered, the thermal efficiency of the cycle of compressorless CCGT unit will be significantly higher. Since it allows to independently regulate a number of parameters, on which the electric power, the ratio of electric and thermal power, the temperature of a working fluid at the turbine inlet depend. Thus, the optimal parameters of the thermodynamic cycle can be obtained in a wide range of operating modes of the unit with different ratios of thermal and eclectic powers. Therefore, the compressorless CCGT unit can significantly surpass the best steam turbine and combined cycle gas turbine plants in district heating system in terms of thermal efficiency.

Improving Energy and Environmental Efficiency of Combined Heat-and Power Plant Based on Absorption Heat Transformers

In the present paper the scheme for increasing the energy efficiency of combined heat and power plants (CHPP) using absorption heat transformers (AHT) is considered. The aim of the study is to increase the energy and environmental efficiency of natural gas use in power supply systems by application steam turbine plants and absorption heat transformers. The simulation of CHPP modernization and a harmful emissions dispersion assessment were carried out using the following software tools: ISC Manager, Thermoflex. All the calculations were made for one power unit of the CHPP in Moscow. Subsequently, the obtained data on energy efficiency increase and harmful emissions reduction were multiplied on the whole power system of Moscow, the main source of heat and electricity of which are the CHPP’s of PJSC “Mosenergo”.

Statistical Analysis for Parametric Optimization of Gas Turbine-Steam Turbine Combined Power Cycle with Different Natural Gas Combustion

The combined Gas Turbine (GT) and Steam Turbine (ST) power generation techniques plays important role in power production. The coal fired thermal power plants have maximum possible efficiency about 34-36% with all arrangements of reheating and regeneration thermal systems. The integration of GT power generation system with old coal based thermal power plant helps to re-powering of plant and utilization of exhaust energy of GT unit through heat recovery steam generator (HRSG) of ST plant. The proposed title of research deals two steps of analysis. Energy analysis is adopted as first step for performance and energy destruction evaluation purpose where as Multi Linear regression (MLR) method is introduced as second method for parametric optimization. The four natural gases have been considered in this analysis and investigate the suitable fuel gas performance as per operating condition of GT plant such as gas turbine inlet turbine temperature (GTIT), compression ratio (CR) and mass flow of gases. The result of this paper concluded as maximum exergy loss found in combustion chamber of GT system and exhaust flow system of ST system in terms of 41% and 8% respectively. The combined and exergetic efficiency of plant are estimated to be 41% and 38.5% respectively. In present statistical model 4 levels and 3 factors (Pressure ratio, operating temperature and type of fuel gases) have been considered. And overall efficiency, gas turbine efficiency, heat loss in GT plant, Exergy destruction in thermal utilities like Compressor, combustion chamber and gas turbine are investigated. The statistical modeling concluded that the comparative results of actual and predicted results at different compression ratio of combustible gases which is affects the overall performance of combined GT-ST plant. This study helps to justify possible efficiency improvement with identifying the irreversibilities of plant utilities.

The influence of air inflow in the vacuum system of a cogeneration steam turbine plant on its energy performance

The article considers the issue of the influence of air inflow in the vacuum system of a cogeneration steam turbine plant on its energy performance. The authors give a brief description of characteristics of a steam turbine condenser. On the example of the T-110/120 turbine plant, they estimate the power loss factor of a low pressure section (LPS) depending on air inflow in a vacuum system on a heat schedule operating mode with steam consumption of 20 t/h. The authors underline a significant influence of air inflow on the amount of power produced by the turbine plant. Moreover, the authors evaluate the power loss of LPS depending on air inflow in the vacuum system on one of the operation modes on the electrical schedule. They demonstrate that an increase in air inflow leads to quite large (hundreds of kilowatts) power losses.

The influence of supercooling of the main condensate at the outlet of the condenser on the operation of a cogeneration steam turbine plant

The article considers the issue of the influence of supercooling of the main condensate on the performance of a steam power plant. We describe the calculation method for a steam turbine condenser. Based on the mathematical model of a condenser, we propose a method for calculating supercooling degree of the condensate on its bottom with different air inflows in a turbo unit vacuum system. The degree of the condensate supercooling on the condenser bottom during the operation of the turbine unit in the heat and electricity production mode is determined in the example of the T-110/120-130 UTZ turbine unit. It is shown that an increase of air inflow into the vacuum system by four times leads to an increase in supercooling of the condensate from 3.5 to 11°C. It has been established that an increase in the condensate supercooling leads to additional heat losses of up to 1.100 kW in the turbine unit per a cycle in the power production operating mode and up to 500 kW per a cycle in the heat production mode.

Calculation of the Energy Complex Based on a Steam Gas Installation Assessment of the Parameters of the Contour of the Auxiliary Steam Power Plant Installation

In this paper, we calculate the parameters of the energy complex on liquefied natural gas (LNG), which serves for the gasification of LNG with its further utilization in the circuit of a steam turbine plant, during operation of which additional electrical energy is generated. We evaluate the effectiveness of regasification of cryoproducts and evaluate the potential of using Cold Energy.Various schemes of power plants using Cold Energy are considered. The parameters and characteristics of the combined-cycle plant consisting of the gas-turbine circuit and the steam-turbine circuit are calculated. The coefficient of cryoproduct energy return (liquefied natural gas) of the considered schemes is calculated and and based on the data obtained, the most optimal one is selected.

Thermodynamic modeling of a heat pump unit as part of a cogeneration turbine operating in ventilation mode

Currently, much attention is paid to improving the efficiency of energy generating facilities through the use of secondary energy resources. This article presented a cogeneration turbine in the general energy scheme with a heat pump installation. During the winter period, due to the increased consumption of heat energy, heat-generating turbines, by closing the regulating diaphragm, are switched to full steam extraction mode from the low-pressure flow part to heat the supply water. In this case, the last stages of the turbine are transferred to the ventilation mode with the release of heat due to the vortex flows on the blades of the low pressure part. In order to obtain additional heat energy for network water, the article considers the option of using secondary energy resources with the help of a heat pump unit operating in a steam turbine plant scheme. All necessary calculations of thermodynamic modeling were carried out according to the EES heat pump, the program working as part of a cogeneration turbine, and the results were obtained of increasing the efficiency of using secondary energy resources with various refrigerants.

Exergy analysis of a cogeneration system for utilization of waste heat of industrial enterprises

The object of research is the energy processes occurring in the cogeneration system for the utilization of waste heat of industrial enterprises, consisting of a steam turbine plant and an absorption heat pump. One of the most problematic places during the development and design of such systems is that the thermal calculation of absorption heat pumps as a whole is a rather difficult task. This is due to the presence of several interconnected heat exchangers and the complexity of the thermodynamic and mass transfer processes occurring in them. During the research, modern methods of analysis of thermodynamic systems were used, based on the application of the theoretical apparatus of technical thermodynamics and the theory of heat and mass transfer. On the basis of mathematical modeling of heat and mass transfer processes for the cogeneration system under consideration, a software package for calculating its thermodynamic and exergy characteristics is built with the aim of conducting numerical studies of its energy efficiency indicators. A database is obtained for calculating the thermophysical properties of a water-ammonia solution taking into account changes in its concentration to identify the solution state parameters at the nodal points of the cycles. Based on a numerical experiment, the energy and exergy parameters of the system are analyzed with a variation of 4 factors: 1) condensation temperature of the spent water steam in a steam turbine plant; 2) heating process water temperature at the inlet to the steam generator of the steam turbine plant; 3) reverse delivery water temperature at the inlet to the heat pump; 4) mass flow rate of delivery water. A generalized regression equation of the functional relationship of the exergy efficiency of the elements of the cogeneration system and the entire system as a whole is obtained. The impact coefficients of exergy efficiency of elements on the thermodynamic perfection of the entire system are analyzed. Thanks to the method of exergy analysis used in the research, it is possible to identify the nature of external and internal losses both in cycles in general and in individual elements of the cogeneration system under consideration. And also the ways to improve its scheme and design are outlined.

Assessment of indicators of efficiency of the steam-turbine mini-thermal power plants burning coal

In work results of calculations of main units of steam -turbine mini-thermal power plants of low power: 6, 11,4, 12, 20 and 25 MW intended for work in the autonomous mode are presented. On the basis of material, thermal and the exergy balances efficiency indicators – the exergy efficiency and specific expenses of fuel are defined. With a greatest exergy efficiency at the level of 33% have MW blocks 6, 20 and 25 that testifies to a possibility of effective combination of the boiler and turbine equipment of this power and also completing of technological schemes of mini-thermal power plant on the basis of the released drying and mill equipment, boilers and turbines of low power.