scholarly journals Up-Rated Reheat Gas Turbine for the Repowering of Steam Power Plants

1999 ◽  
Author(s):  
G. Negri di Montenegro ◽  
A. Peretto ◽  
E. Mantino
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Fossil Fuel ◽  
Lower Cost ◽  
Combined Cycle ◽  
Internal Rate Of Return ◽  
Steam Power ◽  
Steam Power Plants ◽  
Combined Cycles ◽  
Fossil Fuel Power Plants

In the present paper, a thermoeconomic analysis of combined cycles derived from existing steam power plants is performed. The gas turbine employed is a reheat gas turbine. The increase of the two combustor outlet temperatures was also investigated. The study reveals that the transformation of old conventional fossil fuel power plants in combined cycle power plants with reheat gas turbine supplies a cost per kWh lower than that of a new combined cycle power plant, also equipped with reheat gas turbine. This occurs for all the repowered plants analyzed. Moreover, the solution of increasing the two combustor outlet temperatures resulted a strategy to pursue, leading, in particular, to a lower cost per kWh, Pay Back Period and to a greater Internal Rate of Return.

Comparative Thermoeconomic Analysis Between Combined Cycle Units Derived From Existing Steam Power Plants and a New Combined Cycle Plant

1998 ◽  
Author(s):  
G. Negri di Montenegro ◽  
A. Peretto ◽  
E. Mantino
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Pressure Level ◽  
Combined Cycle ◽  
Steam Turbines ◽  
Steam Power ◽  
Steam Power Plants ◽  
Combined Cycle Plant ◽  
Combined Cycles ◽  
The Cost

In this paper, a thermoeconomic analysis is carried out for two and three pressure level combined cycles derived from existing steam power plants. The considered steam power plants are among the most widespread in the Italian territory (70 MW, 160 MW, 320 MW power output). First of all, the gas turbine plants that best match the steam power plants’ requirements are selected among existing units. Subsequently, the thermodynamic analysis for the repowered plants is performed, taking into account the off-design working condition of some components such as, the steam turbines and the condenser. Then, the economic evaluation for the repowered plants is carried out by determining the cost per kWh, the pay back period and the internal rate of return. The analysis permits the most economic choice to be made. The thermoeconomic investigation was also performed for a new combined cycle power plant. The study has revealed that the repowering of the three existing steam power plants in two or three pressure level combined cycle plants is more convenient than building a new combined cycle with higher efficiency. It has also pointed out that the repowering of the 320 MW existing steam power plant in a three pressure level reheat combined cycle plant supplies the lowest cost per kWh among all the other repowered plants analyzed. The revamping and environment effect on the above mentioned existing steam power plants was also investigated and it resulted that this solution has a cost per kWh that is much higher than that of the repowered steam plants and the new combined cycle.

Investigation of Gas Turbine Parameters on Repowering of Existing Steam Power Plants as Fully Fired Combined Cycle

2006 ◽  
Author(s):  
K. Sarabchi ◽  
V. Nayyeri
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Power Output ◽  
Power Plants ◽  
Combined Cycle ◽  
Life Extension ◽  
Steam Power ◽  
Economic Reason ◽  
Steam Power Plants ◽  
Attractive Option

Most of investment in power generation industry tends to combined gas and steam turbine power plants due to thermodynamic and economic reason. Beside this tendency repowering of existing power plants is an attractive option for upgrading and life extension of existing power plants. In fact repowering is usage of combined cycle advantages for increasing power output and efficiency in steam power plants. Several approaches are proposed for repowering regards to condition of existing power plants such as life period and condition of parts of that and most important off all boiler condition. One of this approaches which provide opportunity of existing boiler reusing is converting existing power plant to fully fired combined cycle by installing a gas turbine and integration of that with existing steam units boiler. The aim of this paper is investigation of condition and how to integration of gas turbine and boiler. Also by exerting the condition and limitation in integration, the effect of gas turbine parameters to power output and efficiency of after repowering have been investigated. Finally the best condition of gas turbine parameters with high power and efficiency will be introduced.

scholarly journals Reheat and Regenerative Gas Turbines for Feed Water Repowering of Steam Power Plant

1995 ◽  
Author(s):  
G. Negri di Montenegro ◽  
M. Gambini ◽  
A. Peretto
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Flow Rate ◽  
Gas Turbines ◽  
Power Plants ◽  
Feed Water ◽  
Brayton Cycle ◽  
Energy Integration ◽  
Steam Power ◽  
Steam Power Plants

This study is concerned with the repowering of existing steam power plants (SPP) by gas turbine (GT) units. The energy integration between SPP and GT is analyzed taking into particular account the employment of simple and complex cycle gas turbines. With regard to this, three different gas turbine has been considered: simple Brayton cycle, regenerative cycle and reheat cycle. Each of these cycles has been considered for feed water repowering of three different existing steam power plants. Moreover, the energy integration between the above plants has been analyzed taking into account three different assumptions for the SPP off-design conditions. In particular it has been established to keep the nominal value for steam turbine power output or for steam flow-rate at the steam turbine inlet or, finally, for steam flow-rate in the condenser. The numerical analysis has been carried out by the employment of numerical models regarding SPP and GT, developed by the authors. These models have been here properly connected to evaluate the performance of the repowered plants. The results of the investigation have revealed the interest of considering the use of complex cycle gas turbines, especially reheat cycles, for the feed water repowering of steam power plants. It should be taken into account that these energy advantages are determined by a repowering solution, i.e. feed water repowering which, although it is attractive for its simplicity, do not generally allows, with Brayton cycle, a better exploitation of the energy system integration in comparison with other repowering solutions. Besides these energy considerations, an analysis on the effects induced by repowering in the working parameters of existing components is also explained.

Advances in Power Plant Steam Blow Cleaning Analyses

2004 ◽  
Author(s):  
Julie M. Jarvis ◽  
Paul J. Babel ◽  
Allen T. Vieira
Keyword(s):  
Power Plants ◽  
Dynamic Pressure ◽  
Turbine Blades ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Steam Power ◽  
Steam Power Plants ◽  
Design Coordination ◽  
Modeling Techniques ◽  
Coal Power Plants

Steam blows are used prior to initial turbine powering for steam power plants to clear debris and surface scale that could potentially damage turbine blades during plant operation. Based on experience from steam blows for several dozen plants, enhancements have been made to the techniques in the detailed engineering analysis used by plant startup to perform steam blows. This paper discusses these improvements as applied to combined cycle gas and coal power plants. The basis for steam blows is that the piping is blown, bypassing the turbine, with sufficient boiler pressure to ensure that the piping will experience a dynamic pressure to assure adequate cleaning. Typically, the boiler pressures during steam blow provide a dynamic pressure throughout the piping, which is at least 20% higher than would be experienced for all plant operating conditions. Therefore, any potentially damaging particles will be blown out of the piping prior to the turbine operation. The following improvements and enhancements, which are detailed in this paper, have recently been implemented in the analyses used to establish adequate steam blows: 1. Advanced Modeling Techniques. 2. Design Coordination with Fast Track Engineering. 3. Consideration of Multiple HRSG Plants. 4. Analysis Support During Actual Steam Blows (for site engineering and startup).

Thermoeconomic Analysis of Power Plants With Integrated Exergy Stream

2000 ◽  
Author(s):  
Duck-Jin Kim ◽  
Hyun-Soo Lee ◽  
Ho-Young Kwak ◽  
Jae-Ho Hong
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Power Plants ◽  
Unit Cost ◽  
Combined Cycle ◽  
Cogeneration Plant ◽  
Steam Power ◽  
Unit Costs ◽  
Combined Cycle Plant ◽  
The Cost

Abstract Exegetic and thermoeconomic analysis were performed for a 500-MW combined cycle plant and a 137-MW steam power plant without decomposition of exergy into thermal and mechanical exergy. A unit cost was assigned to a specific exergy stream of matter, regardless of its condition or state in this analysis. The calculated costs of electricity were almost same within 0.5% as those obtained by the thermoeconomic analysis with decomposition of the exergy stream for the combined cycle plant, which produces the same kind of product. Such outcome indicated that the level at which the cost balances are formulated does not affect the result of thermoeconomic analysis, that is somewhat contradictory to that concluded previously. However this is true for the gas-turbine cogeneration plant which produces different kinds of products, electricity and steam whose unit costs are dominantly affected by the mechanical and thermal exergy respectively.

Research on Thermal Efficiencies of Various Power Cycles for GFRs and VHTRs

2018 ◽  
Author(s):  
Mohammed Mahdi ◽  
Roman Popov ◽  
Igor Pioro
Keyword(s):  
Gas Turbine ◽  
Heavy Water ◽  
Nuclear Power ◽  
Power Plants ◽  
Supercritical Pressure ◽  
Combined Cycle ◽  
Power Cycles ◽  
Power Cycle ◽  
Combined Cycles ◽  
Gas Turbine Cycle

The vast majority of Nuclear Power Plants (NPPs) are equipped with water- and heavy-water-cooled reactors. Such NPPs have lower thermal efficiencies (30–36%) compared to those achieved at NPPs equipped with Advanced Gas-cooled Reactors (AGRs) (∼42%) and Sodium-cooled Fast Reactors (SFRs) (∼40%), and, especially, compared to those of modern advanced thermal power plants, such as combined cycle with thermal efficiencies up to 62% and supercritical-pressure coal-fired power plants — up to 55%. Therefore, NPPs with water- and heavy-water-cooled reactors are not very competitive with other power plants. Therefore, this deficiency of current water-cooled NPPs should be addressed in the next generation or Generation-IV nuclear-power reactors / NPPs. Very High Temperature Reactor (VHTR) concept / NPP is currently considered as the most efficient NPP of the next generation. Being a thermal-spectrum reactor, VHTR will use helium as a reactor coolant, which will be heated up to 1000°C. The use of a direct Brayton helium-turbine cycle was considered originally. However, technical challenges associated with the direct helium cycle have resulted in a change of the reference concept to indirect power cycle, which can be also a combined cycle. Along with the VHTR, Gas-cooled Fast Reactor (GFR) concept / NPP is also regarded as one of the most thermally efficient concept for the upcoming generation of NPPs. This concept was also originally thought to be with the direct helium power cycle. However, technical challenges have changed the initial idea of power cycle to a number of options including indirect Brayton cycle with He-N2 mixture, application of SuperCritical (SC)-CO2 cycles or combined cycles. The objective of the current paper is to provide the latest information on new developments in power cycles proposed for these two helium-cooled Generation-IV reactor concepts, which include indirect nitrogen-helium Brayton gas-turbine cycle, supercritical-pressure carbon-dioxide Brayton gas-turbine cycle, and combined cycles. Also, a comparison of basic thermophysical properties of helium with those of other reactor coolants, and with those of nitrogen, nitrogen-helium mixture and SC-CO2 is provided.

Gas Turbine With Constant Volume Heat Addition

2010 ◽  
Author(s):  
S. Can Gu¨len
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Fossil Fuel ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Heat Addition ◽  
Volume Heat

Increasing the thermal efficiency of fossil fuel fired power plants in general and the gas turbine power plant in particular is of extreme importance. In the face of diminishing natural resources and increasing carbon emissions that lead to a heightened greenhouse effect and greater concerns over global warming, thermal efficiency is more critical today than ever before. In the science of thermodynamics, the best yardstick for a power generation system’s performance is the Carnot efficiency — the ultimate efficiency limit, set by the second law, which can be achieved only by a perfect heat engine operating in a cycle. As a fact of nature this upper theoretical limit is out of reach, thus engineers usually set their eyes on more realistic goals. For the longest time, the key performance benchmark of a combined cycle (CC) power plant has been the 60% net electric efficiency. Land-based gas turbines based on the classic Brayton cycle with constant pressure heat addition represent the pinnacle of fossil fuel burning power generation engineering. Advances in the last few decades, mainly driven by the increase in cycle maximum temperatures, which in turn are made possible by technology breakthroughs in hot gas path materials, coating and cooling technologies, pushed the power plant efficiencies to nearly 40% in simple cycle and nearly 60% in combined cycle configurations. To surpass the limitations imposed by available materials and other design considerations and to facilitate a significant improvement in the thermal efficiency of advanced Brayton cycle gas turbine power plants necessitate a rethinking of the basic thermodynamic cycle. The current paper highlights the key thermodynamic considerations that make the constant volume heat addition a viable candidate in this respect. First using fundamental air-standard cycle formulas and then more realistic but simple models, potential efficiency improvement in simple and combined cycle configurations is investigated. Existing and past research activities are summarized to illustrate the technologies that can transform the basic thermodynamics into a reality via mechanically and economically feasible products.

Efficiency Optimization of Four Gas Turbine Power Plant Configurations

2016 ◽  
Author(s):  
Sultan Almodarra ◽  
Abdullah Alabdulkarem
Keyword(s):  
Power Plant ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Power Plants ◽  
Waste Heat ◽  
Combined Cycle ◽  
Conjugate Directions ◽  
Steam Power ◽  
Baseline Design ◽  
Gas Turbine Power Plant

Gas turbine power plants fueled by natural gas are common due to their quick start-up operation and low emissions compared with steam power plants that are directly fired. However, the efficiency of basic gas turbine power plant is considered low. Any improvement in the efficiency would result in fuel savings as well as reduction in CO2 emissions. One way to improve the efficiency is to utilize exhaust gas waste heat. Two waste heat utilization options were considered. The first option was to run a steam power plant (i.e. combined cycle power plant) while the other option was to use a regenerator which reduces the size of the combustion chamber. The regenerator utilizes the waste heat to preheat the compressed air before the combustion chamber. In addition, the efficiency can be improved with compressor intercooling and turbine reheating. In this paper, four gas turbine power plant configurations were investigated and optimized to find the maximum possible efficiency for each configuration. The configurations are (1) basic gas turbine, (2) combined cycle, (3) advanced combined cycle and (4) gas turbine with regenerator, intercooler and reheater. The power plants were modeled in EES software and the basic model was validated against vendor’s data (GE E-class gas turbine Model 7E) with good agreement. Maximum discrepancy was only 3%. The optimization was carried out using conjugate directions method and improvements in the baseline design were as high as 25%. The paper presents the modeling work, baseline designs, optimization and analysis of the optimization results using T-s diagrams. The efficiency of the optimized configurations varied from 49% up 65%.

Parametric Analysis of Combined Cycles Equipped With Inlet Fogging

2006 ◽  
Vol 128 (2) ◽  
pp. 326-335 ◽  
Author(s):  
R. Bhargava ◽  
M. Bianchi ◽  
F. Melino ◽  
A. Peretto
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Cycle ◽  
Advanced Technology ◽  
Fuel Prices ◽  
Power Enhancement ◽  
Wide Range ◽  
Combined Cycles

In recent years, deregulation in the power generation market worldwide combined with significant variation in fuel prices and a need for flexibility in terms of power augmentation specially during periods of high electricity demand (summer months or noon to 6:00 p.m.) has forced electric utilities, cogenerators and independent power producers to explore new power generation enhancement technologies. In the last five to ten years, inlet fogging approach has shown more promising results to recover lost power output due to increased ambient temperature compared to the other available power enhancement techniques. This paper presents the first systematic study on the effects of both inlet evaporative and overspray fogging on a wide range of combined cycle power plants utilizing gas turbines available from the major gas turbine manufacturers worldwide. A brief discussion on the thermodynamic considerations of inlet and overspray fogging including the effect of droplet dimension is also presented. Based on the analyzed systems, the results show that high pressure inlet fogging influences performance of a combined cycle power plant using an aero-derivative gas turbine differently than with an advanced technology or a traditional gas turbine. Possible reasons for the observed differences are discussed.

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