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TPP-9 of PJSC "Mosenergo" is equipped with an AE64.3A gas turbine (manufactured by Ansaldo Energia) delivering flue gases to a Pr-94-13.8-545 single pressure vertical heat recovery steam generator (P-111, manufactured by JSC "ZiO-Podolsk") used for generating superheated steam as well as providing heat for district heating. The generated steam enters the TPP-9 common steam header with the designed pressure of 13.8 MPa and is further used for driving steam turbines. The common steam header is also fed by conventional steam boilers located at TPP-9. Under the current scheme, the gas turbine unit (GTU) and HRSG operation is only possible in conjunction with conventional steam boilers and, therefore, separate operation of GTU, HRSG with any of steam turbines as a power unit is impossible. The requirement for joint operation of GTU, HRSG, and conventional boilers imposes significant restrictions on operating equipment as well as the load range of TPP-9 and causes low GTU, HRSG annual operating time primarily occurring during the fall-winter period. The latter is further worsened by the fact that GTU, HRSG operation is mostly appropriate during the spring-summer period providing compensation for the TPP efficiency decrease caused by a low heat output. An increase in GTU, HRSG annual operating time is possible after retrofitting the current TPP-9 thermal scheme allowing operation of GT, HRSG as a power unit with an existing or newly installed steam turbine, which will simultaneously provide an increase in TPP-9 technical and economic indicators as well as equipment readiness and maneuverability. This will provide the opportunity to optimize operation according to the current loads schedule while maintaining the reliable power and heat output. [ABSTRACT FROM AUTHOR]

The use of an anti-icing air heating system (AHS) at the inlet to the compressor of a gas-turbine unit (GTU) at extremely low negative outdoor temperatures is analyzed. Due to its poor dynamic properties and the need to maintain the air temperature at the inlet to the compressor higher than –20°C, the AHS is continuously operated at an air temperature lower than 8°C. At air temperatures below –5°C, the delivery of the GTU compressor is decreased to meet the strength requirements to the flow part of the GTU. This reduces the power output of the steam turbine and the CCPP. To increase the delivery of the compressor in these cases, the air should be heated in the AHS. A beneficial effect is achieved when using the steam extracted from the steam turbine in the AHS. This decreases the heat loss in the condenser and increases the steam output of the heat recovery steam generator, the output of the steam turbine and the power unit as a whole. The increase in the output of the steam turbine exceeds its power underproduction because of the steam extraction for the AHS. [ABSTRACT FROM AUTHOR]

The description of the equipment of the combined-cycle power plant CCPP-400, operated at the Shatura power station, is given. The thermal characteristics of the equipment of the CCPP obtained as a result of processing operating modes are presented: gas turbine unit (GTU), heat-recovery steam generator (HRSG), steam turbine (ST), and power unit as a whole; their features are analyzed. The dependencies of the main thermal characteristics of GTU, HRSG, and ST on the determining factors are graphically shown. The comparison of thermal characteristics obtained after the power unit was put into operation and after 10 years of active operation is performed. [ABSTRACT FROM AUTHOR]

The article presents the experience of Mosénergo in the introduction of combined-cycle power plants into participation in normalized primary frequency control. Examples of combined-cycle power plants certification tests results are presented, and difficulties encountered in preparing combined-cycle power plants for certification are formulated. [ABSTRACT FROM AUTHOR]

Because the generator power-measuring equipment is often accompanied by electrical interference in a complex electromagnetic environment in an actual thermal power plant, the output signal will change or even distort while it passes through the devices of acquisition and conversion. Several practical cases have found that the abnormal generation change phenomenon, impulse or oscillation caused by electrical interference, has different effects on the load regulation of steam turbines. These faults also exist in combined-cycle power plants (CCPPs). However, the insufficient installed capacity and operating life of CCPPs domestically cause similar load mutation failures that are scarcely found. We had to acknowledge that CCPPs and steam turbine regulation characteristics differ. It is of great value to study the influence of differences in load mutation on the load regulation of single-shaft CCPPs. We extracted the fault characteristics of two sudden load change phenomena using the operation data of an actual steam turbine and analyzed them through simulation. Furthermore, a fault detection and isolation method for sudden load changes in a single-shaft CCPP was proposed and the simulation results verified the method's effectiveness. [ABSTRACT FROM AUTHOR]

In order to determine an unavailability of each safety function subsystem that influences on an overall unavailability of entire protection system for safety analysis and enhancement, a modeling is required. This article presents a safety system modeling to evaluate the detected–undetected failures and repairable behaviors of each safety function subsystem in the studied fuel gas supply system (FGSS), which is utilized in a combined-cycle power plant. The proposed modeling deals with probability of failure on demand (PFD) analysis for calculation of the unavailability of three safety function subsystems, which are gas analytical subsystem (GAS), fuel gas controller subsystem (FGC), and shutdown valve subsystem (SDV). The interested GAS includes two different groups of gas analyzers in 2-out-of-2 (2oo2) voting scheme, when using three gas analyzers in each group in 2-out-of-3 and diagnosis (2oo3D) voting scheme. The interested FGC consists of two controllers in 2oo2 voting scheme, when the structure of each controller is in 1-out-of-1 and diagnosis (1oo1D) voting scheme. The interested SDV consists of two shutdown valves, which are installed in 1-out-of-2 (1oo2) voting scheme. The reliability block diagram is utilized for representative of combination of all three safety function subsystems, and the fault tree is utilized for calculation of PFD unavailability of each safety function subsystem. As the results obtained from the proposed safety function modeling, the influence of three safety function subsystems on the total unavailability of the FGSS is described. In addition, an example of the proposed modeling application to provide two guidelines for effective engineering design and operation is also presented. The first is a guideline to implement an effective human machine interface (HMI) at an operator workstation for real-time monitoring of the studied FGSS in the presence of failures that can be automatically detected by device diagnosis. The latter is a guideline to maintain and troubleshoot the failures that can be revealed by proof test. Based on diagnostic information and proof test results, operation and maintenance savings can be achieved.

Along with improving the cooling technology, increasing the combustor outlet temperature is currently one of the main ways to raise the efficiency of both gas-turbine and combined-cycle power plants. The efficiency of the cooling technology is determined by four main parameters: internal cooling efficiency, film cooling effectiveness, Biot numbers for the blade metal and thermal barrier coating. This paper presents comprehensive calculations of gas turbine performance with varying combustor outlet temperature, compressor pressure ratio, and cooling efficiency. With modern cooling systems, an increase in the inlet gas temperature by 100°C leads to an increase in the efficiency of the combined-cycle plant by 0.5 – 0.8%. An increase in the inlet gas temperature to 1600°C with simultaneous improvement of the cooling technology will increase the efficiency of combined-cycle power plants to 62 – 63% and higher. The calculations provide an overview and lead to conclusions that are of importance for gas turbine designers. [ABSTRACT FROM AUTHOR]

This article aims to present a technique to enhance reliability of liquefied natural gas (LNG) fuel gas supply system (FGSS) of gas turbine unit in a combined-cycle power plant. In order to prevent unplanned plant shutdowns, the proposed technique is based on the use of failure modes, effects, and diagnostic analysis (FMEDA) to identify and evaluate the effects of possible failure modes, to determine what could minimize the chance of failures, and to design a new safety interlock. The studied FGSS consists of gas analytical system (GAS) in 2-out-of-2 voting scheme, shutdown valve system (SDV) in 1-out-of-2 voting scheme, fuel gas controller (FGC), and engineering/operator workstations. Two automatic GAS subsystems with different measurement methods are installed in the GAS. One of two GAS subsystems uses three gas chromatography analyzers in 2-out-of-3 voting scheme. The gas chromatography results and diagnostic alarm historian are utilized to consider the failure behavior. The reliability models for the GAS subsystem using gas chromatography and the overall FGSS are also included to confirm the effectiveness of utilizing diagnostic information from the gas analyzers. Based on the FMEDA results, the new safety interlock with no additional software and hardware costs can be achieved. The workability of the proposed safety interlock is demonstrated by test results.

Abstract In this study, energy‐exergy analysis is performed for the gas‐fired combined‐cycle power plant which will be constructed in Kuantan and Kapar in the Malay Peninsula in 2020. The main objectives of this current study are first and second law evaluation of the powerplant's main components consisting of the gas turbine unit, condenser, heat recovery steam generator, and triple‐pressure steam turbines. By energy‐exergy analysis, we can not only evaluate the exact magnitude of exergy destruction and efficiency in each component separately but analyze either major or trivial effects of environment condition variations on plant components. Performance effects are also pinpointed when the pressure ratio, reference temperature, HPT and condenser pressure, reheating and stack temperature change. In the current investigation, more than 808 MW of exergy destruction to the environment mainly occurs in the gas turbine cycle with around 83.79% of total exergy destruction, followed by HRSG (11.3%), steam turbines (roughly 2.58%), and condenser (2.54%). Additionally, exhaust gas fractions from the gas turbine across the combustor are calculated as well wherein the average molar fraction of nitrogen, oxygen, carbon dioxide, and water vapor is calculated to be 76.42%, 17.57%, 1.37%, and 4.64%, respectively. In conclusion, several constructive possibilities for CCPP’s performance development based on the obtained results are introduced. With regard to the construction of this project in 2020, energy‐exergy assessment, as well as optimization guidance, can be worthwhile for better modifying some operating conditions and taking advantage of the trivial destruction rate simultaneously.

In the coming years, numerous regions are expected to suffer from water scarcity. One of the technologies of great interest in facing this challenge has been the generation of freshwater through water desalination, a process that reduces the amount of salt and minerals to a standard level, making the water suitable for drinking or agricultural/industrial use. The efficiency of each desalination process depends on the concentration of salts in the raw water and the end-use of the produced water. The present study presents the exergetic and exergoeconomic analyses of the coupling of a power plant with desalination units for the simultaneous generation of energy and water in Iran. The plant is integrated, first, with a multi-stage flash (MSF) unit and, then, with a multi-effect desalination (MED) unit. We find that the cost of exergy destruction of the MED and MSF integrated plants is lower when compared to the standalone power plant by about 0.1% and 9.2%, respectively. Lastly, the freshwater production in the plant using MED is significantly higher than that in the plant with MSF (1,000 versus 1,521 kg/s).

Rising water scarcity and abundant brine water resources, especially in desert locations, call for the wider adaptation of desalination techniques. Furthermore, the interdependency of water and energy has gained more attention in recent years and it is expected to play an important role in the near future. The present study deals with both topics in that it presents the coupling of a power plant with desalination units for the simultaneous generation of energy and water in Iran. The power plant used in the analysis is the Qom combined-cycle power plant. The plant is integrated, first, with a multi-stage flash (MSF) unit and, then, with a multi-effect desalination (MED) unit, and it is evaluated using energy and exergy analyses. We find that the generated power of the integrated systems is decreased by 9.7% and 8.5% with the MED and the MSF units, respectively. Lastly, the freshwater production in the plant using MED is significantly higher than in the plant with MSF (1,000 versus 1,521 kg/s).

Because the generator power-measuring equipment is often accompanied by electrical interference in a complex electromagnetic environment in an actual thermal power plant, the output signal will change or even distort while it passes through the devices of acquisition and conversion. Several practical cases have found that the abnormal generation change phenomenon, impulse or oscillation caused by electrical interference, has different effects on the load regulation of steam turbines. These faults also exist in combined-cycle power plants (CCPPs). However, the insufficient installed capacity and operating life of CCPPs domestically cause similar load mutation failures that are scarcely found. We had to acknowledge that CCPPs and steam turbine regulation characteristics differ. It is of great value to study the influence of differences in load mutation on the load regulation of single-shaft CCPPs. We extracted the fault characteristics of two sudden load change phenomena using the operation data of an actual steam turbine and analyzed them through simulation. Furthermore, a fault detection and isolation method for sudden load changes in a single-shaft CCPP was proposed and the simulation results verified the method’s effectiveness.

The retrofitting of two single-boiler-single-turbine units of the first stage of the Sochi TPP by adding cross-connections between them is considered. These cross-connections made it possible to reduce the minimum safe electrical output of these power units by shutting down one gas turbine and keeping both steam turbines in operation. The principal features of the retrofitting are shown. The effect of retrofitting is analyzed at the stage of testing and in a year of operation. [ABSTRACT FROM AUTHOR]

In most large cities of Russia, the annual heat consumption exceeds the annual electricity consumption more than twice as a rule. On the contrary, the electric power of the combined-cycle cogeneration heat-power plant (CCCHPP) with heat-recovery steam generators (HRSG) is much higher than the thermal power of the cogeneration extraction of its steam turbine plant. This necessitates equipping combined-cycle gas turbine–combined heat and power plants (CCGT–CHPP) with additional heat sources to cover the heat loads of the heating season, which exceed the heat capacity of the cogeneration extractions of the combined-cycle gas turbines. The article shows that the use of water-heating boilers in this capacity has a number of serious disadvantages. These disadvantages can be eliminated by equipping HRSGs with afterburner units (ABUs), which burn the gas fuel in the residual oxygen of the exhaust gases of the gas turbine engine (GTE) directly in the HRSG. The range of thermal loads can be expanded, and the efficiency of the ABU application can be significantly increased by mounting the ABUs in the HRSG downstream from the high-pressure steam superheater upstream from the high-pressure evaporator. Furthermore, it is necessary to integrate a number of new components into the HRSG configuration, such as a water low-pressure steam superheater (WLPSSH) used instead of the gas LPSSH, a reduction device, and a peak network heater included in the heating plant of the steam turbine unit as the third stage of the network water heater at high (peak) thermal loads. By the example of the PGU-450T CCCHPP, the fundamental possibility of implementing the proposed modernization of its complete HRSG without making any changes to the design of the steam turbine is shown. Since the low-pressure drum of this HRSG is additionally equipped with a deaeration unit, the upgraded HRSG of the PGU-450T plant had also to be equipped with a water condensate heater upstream from the deaerator and additional shut-off and control valves that maintain the pressure in the deaerator and assure the subcooling of the water condensate at the deaerator inlet within the permissible range of all operating modes as well as under changing thermal loads all the year round. [ABSTRACT FROM AUTHOR]

A dynamic model of a triple-pressure heat-recovery steam generator (HRSG) is developed. The basic equations of the model are described. Cold and hot start-ups of an HRSG are simulated. The simulation results are compared with archive data on start-ups of real equipment. Conclusions on future application of the simulation data are drawn. [ABSTRACT FROM AUTHOR]

In this study, energy‐exergy analysis is performed for the gas‐fired combined‐cycle power plant which will be constructed in Kuantan and Kapar in the Malay Peninsula in 2020. The main objectives of this current study are first and second law evaluation of the powerplant's main components consisting of the gas turbine unit, condenser, heat recovery steam generator, and triple‐pressure steam turbines. By energy‐exergy analysis, we can not only evaluate the exact magnitude of exergy destruction and efficiency in each component separately but analyze either major or trivial effects of environment condition variations on plant components. Performance effects are also pinpointed when the pressure ratio, reference temperature, HPT and condenser pressure, reheating and stack temperature change. In the current investigation, more than 808 MW of exergy destruction to the environment mainly occurs in the gas turbine cycle with around 83.79% of total exergy destruction, followed by HRSG (11.3%), steam turbines (roughly 2.58%), and condenser (2.54%). Additionally, exhaust gas fractions from the gas turbine across the combustor are calculated as well wherein the average molar fraction of nitrogen, oxygen, carbon dioxide, and water vapor is calculated to be 76.42%, 17.57%, 1.37%, and 4.64%, respectively. In conclusion, several constructive possibilities for CCPP's performance development based on the obtained results are introduced. With regard to the construction of this project in 2020, energy‐exergy assessment, as well as optimization guidance, can be worthwhile for better modifying some operating conditions and taking advantage of the trivial destruction rate simultaneously. [ABSTRACT FROM AUTHOR]

In Pakistan, the thermal efficiency of the power plants is low because of a huge share of fuel energy is dumped into the atmosphere as waste heat. The ORC (Organic Rankine Cycle) has been revealed as one of the promising technologies to recover waste heat to enhance the thermal efficiency of the power plant. In current work, ORC is proposed as a second bottoming cycle for existing CCPP (Combined Cycle Power Plant). In order to assess the efficiency of the plant, a thermodynamic model is developed in the ESS (Engineering Equation Solver) software. The developed model is used for parametric analysis to assess the effects of various operating parameters on the system performance. The analysis of results shows that the integration of ORC system with existing CCPP system enhances the overall power output in the range of 150.5-154.58 MW with 0.24-5% enhancement in the efficiency depending on the operating conditions. During the parametric analysis of ORC, it is observed that inlet pressure of the turbine shows a significant effect on the performance of the system as compared to other operating parameters.

A technique for calculating the standardized indicators characterizing the thermal efficiency of combined-cycle power plants (CCPPs) using correlation equations linking the values of these indicators with different external conditions is proposed. The correlation equations were written using the results from measuring the outdoor air and cooling water temperatures; air barometric pressure and humidity; fuel (natural gas) flowrate, heating value, and density and load in steady-state operation modes of the CCPPs and their equipment. It is usually sufficient to have a sample with three groups each representing 15–20 operating modes: under winter conditions at an outdoor air temperature of –20 to –30°С, under summer conditions at an outdoor air temperature of above 20 to 30°С, and at an intermediate temperature of ±5 to ±7°С. In each group, it is sufficient to have two operating modes each with loads close to 0.5, 0.6, 0.7, 0.8, and 0.9 of the maximal value, and 5–10 operating modes with a close-to-nominal load. It is shown, taking a single-shaft 400 MW CCPP as an example, that the correlation equations adequately (with errors equal to approximately 1%) describe the results obtained experimentally in the normal operation modes. The developed technique opens the possibility to determine, in a more accurate and simple manner, the standardized heat rates and other technical-economic indicators of fuel utilization without using an excessive number of corrections able to distort the result. The technique can also be used for estimating the changes of CCPP indicators as a result of taking some or other measures in them. [ABSTRACT FROM AUTHOR]

The chief issues in the operation of combined-cycle power plant (CCPP) heat recovery steam generators at the stage of maturation of this technology in the power industry of Russia are outlined. The design evolution is shown for heat recovery steam generators (HRSG), reflecting the problems of ensuring rapid start-ups of CCPPs and limiting the failure rate of thick-walled elements of the HRSG steam-water path; and an approach is proposed for designing programs for maintenance of heat exchange steam generators. [ABSTRACT FROM AUTHOR]

Depending on the requirements for power plants at thermal power stations (TPS), alternative approaches can be used for constructing assignment schedules to start power units from different initial thermal states. This issue becomes topical for combined-cycle power plants (CCPP) with heat-recovery steam generators (HRSG) whose thermal cycle includes gas turbines featuring excellent maneuverability and a steam system with equipment characterized by a relatively low loading rate. This paper examines an approach to construction of assignment schedules for CCPP starting based on accumulation of damages of the most heavily loaded thickwall elements in the steam path to meet the requirements for CCPP maneuverability during the entire service life of a CCPP. A principle is proposed for constructing an assignment schedule for starting a CCPP from any initial thermal state within the desired time provided that the number of these startups would not exceed the prescribed limit value determined in assessing the damage accumulation. Assignment schedules must be prepared based on the monitored temperature conditions of CCPP equipment, the allowable limits for predicted temperature stresses, and the allowable number of cycles determined by the low-cycle fatigue. [ABSTRACT FROM AUTHOR]

Recently, one of the major and serious worldly concerns is the limitation of energy resources. Sudan, in specific, confronts a critical crises relating to fossil fuel resources, and mostly concerning the production of electricity energy from fired thermal power plants. One of these Garri “2” combined cycle power plants produce about 180 MW. In the light of the second law of thermodynamics, exergy analysis is considered a powerful and effective tool to investigate the optimization of engineering devices. In order to evaluate exergetic efficiency and exergy destruction of each part, exergy analysis has been carried out for Garri “2;” while in order to achieve it, exergy balance and entropy generation were analyzed. Conclusively, the results proved that combustion chambers are the main sources of exergy destruction due to their high irreversibility. These results in detail illustrate the following percentages: 63% from the total exergy destruction, followed by 13.6% of gas turbines, 6.4% steam turbines, 6.3% heat recovery steam generators (HRSGs), 4.7% stacks (exhaust gases), 3.8% compressors and 2.3% cooling systems. Moreover, the results affirmed that thermal and exergetic efficiencies for the entire plant are (38%, 49%) respectively. [ABSTRACT FROM AUTHOR]

A new method for determining the optimal heat-exchanger layout in a heat recovery steam generator and its operating parameters are presented in this paper. A robust mathematical model is developed, where arbitrary steam-pressure levels and steam-reheating levels can be set. The method considers all the possible heat-exchanger layouts, in both serial and parallel arrangements of steam pressure levels or steam reheating levels. The maximum thermodynamic efficiency of the steam-turbine cycle is set as the objective function. The results show that the optimal high pressure in heat recovery steam generator without reheating is in the region of subcritical pressures, whereas that for a heat recovery steam generator with reheating is in the region of supercritical pressures. In the case of similar water or steam temperature profiles in the heat exchangers of different steam pressure levels or reheating level, from a thermodynamic viewpoint, it is justified to use a parallel heat-exchanger arrangement. [ABSTRACT FROM AUTHOR]

The combustion process of gas turbine systems is typically associated with the highest thermodynamic inefficiencies among the system components. A method to increase the efficiency of a combustor and, consequently that of the gas turbine, is to increase the temperature of the entering combustion air. This measure reduces the consumption of fuel and improves the environmental performance of the turbine. This paper studies the incorporation of a volumetric solar receiver into existing gas turbines in order to increase the temperature of the inlet combustion air to 800 °C and 1000 °C. For the first time, detailed thermodynamic analyses involving both energy and exergy principles of both small-scale and large-scale hybrid (solar-combined cycle) power plants including volumetric receivers are realized. The plants are based on real gas turbine systems, the base operational characteristics of which are derived and reported in detail. It is found that the indications obtained from the energy and exergy analyses differ. The addition of the solar plant achieves an increase in the exergetic efficiency when the conversion of solar radiation into thermal energy (i.e., solar plant efficiency) is not accounted for in the definition of the overall plant efficiency. On the other hand, it is seen that it does not have a significant effect on the energy efficiency. Nevertheless, when the solar efficiency is included in the definition of the overall efficiency of the plants, the addition of the solar receiver always leads to an efficiency reduction. It is found that the exergy efficiency of the combustion chamber depends on the varying air-to-fuel ratio and, in most cases, it is maximized somewhere between the applied inlet combustion air temperatures of 800 °C and 1000 °C. [ABSTRACT FROM AUTHOR]

In Pakistan, the thermal efficiency of the power plants is low because of a huge share of fuel energy is dumped into the atmosphere as waste heat. The ORC (Organic Rankine Cycle) has been revealed as one of the promising technologies to recover waste heat to enhance the thermal efficiency of the power plant. In current work, ORC is proposed as a second bottoming cycle for existing CCPP (Combined Cycle Power Plant). In order to assess the efficiency of the plant, a thermodynamic model is developed in the ESS (Engineering Equation Solver) software. The developed model is used for parametric analysis to assess the effects of various operating parameters on the system performance. The analysis of results shows that the integration of ORC system with existing CCPP system enhances the overall power output in the range of 150.5-154.58 MW with 0.24-5% enhancement in the efficiency depending on the operating conditions. During the parametric analysis of ORC, it is observed that inlet pressure of the turbine shows a significant effect on the performance of the system as compared to other operating parameters. [ABSTRACT FROM AUTHOR]

This article discusses international practice to date in the operation of combined-cycle power plants (CCP) on blast-furnace gas (BG). It describes the most common schemes of BG use from the European list of the best available technologies for the metallurgical industry. Combined-cycle power plants in Japan and China are used as examples to demonstrate the technical-economic effectiveness of employing heatrecovery CCPs. The properties of blast-furnace gas are compared to the properties of other industrial gases. The energy potential of blast-furnace gas is calculated and compared to the potential of natural gas. The principles behind the upgrade of a standard gas-turbine power plant to burn blast-furnace gas are examined. The article also presents theoretical results obtained by the authors in the software package Thermoflow to illustrate the efficiency of burning blast-furnace gas in CCPs at Russian plants. [ABSTRACT FROM AUTHOR]

Activities aimed at substantiating the maneuverability characteristics of power-generating equipment installed at district heating power plants (DHPP) and especially at combined-cycle power plants (CCPPs) are quite topical for the modern conditions and involve calculations of thermally stressed state and analysis of the cyclic strength of steam path critical elements at different loading rates. Until recently, such problems have been solved in two possible ways: based on the results of tests carried out on operating equipment and using the mathematical models of heavily stressed parts of CCPP equipment. In this article, preference is given to the second way. The results of mathematical modeling represented as time dependences of the temperature state of equipment critical parts were taken as initial data for calculating their thermally stressed state and for analyzing their damageability according to the criterion of the equivalent operating hours. This criterion is an integral indicator characterizing the extent of damage accumulated in equipment parts and can be used for elaborating equipment maintenance programs. A dependence of the equivalent operating hours on the initial temperature of the metal of the high-pressure steam superheater's outlet header, the component imposing the strongest limitations on the power unit loading rate, is obtained. It is shown that the number of equivalent operating hours of the CCPP steam circuit part equipment accumulated during hot startups does not have any essential effect on the equipment service life (heat-recovery steam generators, steam turbine, and steam lines). [ABSTRACT FROM AUTHOR]

Conventional exergy-based analyses reveal options for improving energy conversion systems, but they suffer from some limitations that are addressed by advanced exergy-based analyses. Advanced exergy-based methods are capable of (1) identifying interdependencies among plant components (endogenous/exogenous values), and (2) revealing the potential for improvement (avoidable/unavoidable values). Thus, data obtained from these methods pinpoint strengths and weaknesses of energy conversion systems and are of great importance when complex plants with a large number of interconnected components are considered. This paper presents one of the first applications of an advanced exergoeconomic analysis to a complex power plant. The plant includes a mixed conducting membrane for oxy-fuel combustion and CO 2 capture. The results show that for the most influential components of the plant, the largest part of investment cost and of the costs of exergy destruction is unavoidable. Additionally, in most cases the interactions among the components are of lower importance and, for the majority of the components, the endogenous parts of the costs (related to the internal operation of each component) are significantly larger than the corresponding exogenous parts (related to component interactions). Nevertheless, relatively strong interactions have been found among the components that constitute the mixed conducting membrane reactor of the plant. [ABSTRACT FROM AUTHOR]

The design of a modular SVBR-100 reactor with a lead-bismuth alloy liquid-metal coolant is described. The basic thermal circuit of a power unit built around the SVBR-100 reactor is presented together with the results of its calculation. The gross electrical efficiency of the turbine unit driven by saturated steam at a pressure of 6.7 MPa is estimated at η = 35.5%. Ways for improving the efficiency of this power unit and increasing its power output by applying gas-turbine and combined-cycle technologies are considered. With implementing a combined-cycle power-generating system comprising two GE-6101FA gas-turbine units with a total capacity of 140 MW, it becomes possible to obtain the efficiency of the combined-cycle plant equipped with the SVBR-100 reactor η = 45.39% and its electrical power output equal to 328 MW. The heat-recovery boiler used as part of this power installation generates superheated steam with a temperature of 560°C, due to which there is no need to use a moisture separator/steam reheater in the turbine unit thermal circuit. [ABSTRACT FROM AUTHOR]

When a combined-cycle power plant operates as part of a combined heat power plant, the optimal load-sharing among the power-generating units of the station is complicated owing to specific features of operating a combined-cycle power plant, viz., the dependence of its adjustment range values on the outdoor air temperature, degradation of the ecological and economic performance figures under underloading conditions, possibility of load-sharing between the gas turbines, and a high flexibility. A method for optimal sharing of the load among the power-generating plants of combined heat power plants is proposed that takes into consideration the above features of the combined-cycle power plants. The combined heat power plant is divided into 'equivalent' units according to the group power supply points. The first step is the intra-unit optimization over the entire variation range of the thermal and electric loads to achieve the best energy performance of the 'equivalent' unit. The second step is the optimization of the load-sharing among the 'equivalent' units. [ABSTRACT FROM AUTHOR]

This paper explores the layout of an optimum process for supplying heat to Russian municipal heating systems operating in a market environment. We analyze and compare the standard cogeneration unit design with two-stage reheating of service water coming from controlled extraction locations and layouts that employ three in-line reheaters with heat the supply controlled by a rotary diaphragm and qualitative/quantitative methods (so-called “uncontrolled extraction”). Cogeneration unit designs are benchmarked in terms of their thermal efficiency expressed as a fuel consumption rate. The specific fuel consumption rate on electricity production is viewed as a key parameter of thermal efficiency.

This paper presents an evaluation of the environmental performance of an advanced zero emission plant (AZEP) including CO2 capture. The evaluation is conducted with the aid of an advanced exergoenvironmental analysis. The results are compared with those of a reference combined-cycle power plant without CO2 capture. Advanced exergy-based methods are used to (a) quantify the potential for improving individual components or overall systems, and (b) reveal detailed interactions among components--two features not present in conventional analyses, but very useful, particularly when evaluating complex systems. In an advanced exergoenvironmental analysis, the environmental impacts calculated in a conventional exergoenvironmental analysis are split into avoidable/ unavoidable (to evaluate the potential for component improvement) and endogenous/exogenous (to understand the interactions among components) parts. As in the reference plant, the potential for reducing the environmental impact of the AZEP has been found to be limited by the relatively low avoidable environmental impact associated with the thermodynamic inefficiencies of several of its components. However, although the environmental impacts for the majority of the components of the plant are related mainly to internal inefficiencies and component interactions are of secondary importance, there are strong interactions between the reactor and some other components. [ABSTRACT FROM AUTHOR]

Highlights: [•] An exergetic analysis is used to identify the thermodynamic irreversibilities of a power plant. [•] The plant includes a solid-oxide fuel-cell unit and CO2 capture. [•] Additional power generated in the fuel-cell unit enhances the power output of the plant. [•] The power plant results in a high efficiency compared both to conventional and other CO2 capture plants. [•] High irreversibilities are found for the solid-oxide fuel cell. [Copyright &y& Elsevier]

This article is devoted to the retrofitting of one of the 300-MW power units at the Kirishi district power station carried out using the combined-cycle technology in order to increase the power unit capacity and make it more efficient. The main and auxiliary equipment of the retrofitted power unit are described. The problems revealed and solved in the course of adjustment works are mentioned. Problems concerned with organizing the startup modes of combined-cycle power units fitted with three-loop heat-recovery boilers and a double-bypass startup circuit arrangement are touched. The design and actually achieved technical and economic indicators of the main equipment and the power unit as a whole are presented. A tangible economic effect is noted from a comparison of the key indicators before and after the retrofitting. It is shown that the retrofitted power unit has good environmental indicators and a very high level of automation. [ABSTRACT FROM AUTHOR]

Abstract: An advanced exergy analysis is reported for a recently developed configuration of an externally-fired combined-cycle power plant integrated with biomass gasification. The results identify the potential for improvement of the overall system considering interactions among the components. It is found that interactions between the components are not very strong, i.e. the endogenous exergy destruction within each component is higher than the exogenous ones. Also, the advantages are demonstrated of advanced exergy analysis over conventional exergy analysis; it is concluded that the focus for improving cycle performance should be on the heat exchanger and not the combustion chamber or gasifier, even though these have the highest exergy destructions among all the components. In addition, it is concluded that the unavoidable part of exergy destruction in almost all components is higher than the avoidable value. Therefore little can be done to reduce the irreversibilities for components of the externally-fired combined-cycle power plant. [Copyright &y& Elsevier]

We present technical characteristics of the equipment used in the PGU-180 power units of the Adler thermal power station (a branch of OGK-2) commissioned in November 2012 after the entire power plant had successfully passed an integrated test, including qualification of the entire power plant's capacity and tests aimed at determining the guaranteed characteristics. [ABSTRACT FROM AUTHOR]

Results from an analysis of permissible initial steam temperatures and heating rates of the outlet headers of high-pressure steam superheaters and the steam lines of combined-cycle plants at which their cyclic strength is ensured are presented. A procedure is proposed using which startup assignment schedules for different thermal states can be constructed proceeding from the heating rates and initial steam temperatures selected depending on the initial temperature state of the high-pressure steam superheaters' outlet headers. [ABSTRACT FROM AUTHOR]

The modern state of technology for making gas turbines around the world and heat-recovery combined-cycle units constructed on their basis are considered. The progress achieved in this field by Siemens, Mitsubishi, General Electric, and Alstom is analyzed, and the objectives these companies set forth for themselves for the near and more distant future are discussed. The 375-MW gas turbine unit with an efficiency of 40% produced by Siemens, which is presently the largest one, is subjected to a detailed analysis. The main specific features of this turbine are that the gas turbine unit's hot-path components have purely air cooling, due to which the installation has enhanced maneuverability. The single-shaft combined-cycle plant constructed on the basis of this turbine has a capacity of 570 MW and efficiency higher than 60%. Programs adopted by different companies for development of new-generation gas turbine units firing synthesis gas and fitted with low-emission combustion chambers and new cooling systems are considered. Concepts of rotor blades for new gas turbine units with improved thermal barrier coatings and composite blades different parts of which are made of materials selected in accordance with the conditions of their operation are discussed. [ABSTRACT FROM AUTHOR]