Modular Repowering of Power Plants With Nominal Ratings Lower Than 180 MW: A Rational Design Approach and Its Application to the Italian Utility System

1994 ◽  
Vol 116 (3) ◽  
pp. 201-210 ◽  
Author(s):  
R. Melli ◽  
V. Naso ◽  
E. Sciubba
Keyword(s):  
Energy Conservation ◽  
Power Plants ◽  
Rational Design ◽  
Large Scale ◽  
Combined Cycle ◽  
Public Utility ◽  
Electricity Production ◽  
Conservation Program ◽  
Steam Power Plants ◽  
Plant Reconfiguration

The paper describes the rationale, the technical/economical details and the results of a study which is part of a large-scale energy conservation program enacted by the Italian Public Utility (ENEL), within a broader framework of structural interventions on the national electricity production/transportation/utilization network. The objective of the larger, long-term plan is to increase by a significant percentage (>5 percent) the net conversion efficiency of the national system. The purpose of the present study is to “recover” a large number of nearly obsolete steam power plants by converting them to a combined cycle configuration. The expression “generalized repowering” has been used to synthetically describe this plant reconfiguration plan, and will be employed in this paper. After giving a brief description of the existing Italian electricity generation situation, we list some possible criteria for repowering and describe in detail the configurations which were considered to be feasible. Finally, the proposed options are comparatively analyzed, and the major parameters which can be of importance in the actual decision-making process on the part of the Public Utility are computed and presented in tabular form. In the conclusions we try to put the present work in the broader perspective of a largescale (supernational), economically sound and ecologically acceptable energy conservation program.

Cycling Tolerance: Natural Circulation Vertical HRSGs

2003 ◽  
Author(s):  
Pascal Fontaine
Keyword(s):  
Gas Turbines ◽  
Power Plants ◽  
Natural Circulation ◽  
Electrical Power ◽  
Combined Cycle ◽  
Public Utility ◽  
Published Data ◽  
Operating Pressure ◽  
Load Following ◽  
To Come

The US market is currently making a double jump in its HRSG requirements. Heretofore, HRSGs were used largely in industrial size cogen applications. According to the PURPA (Public Utility Regulatory Policy Act), public utilities were required to purchase that electric power generated in excess of the steam host’s needs. Thus, HRSGs were relatively small and operated under constant conditions. Now, HRSGs are much larger (utility size) and also more complex due to the introduction of triple pressure plus reheat behind powerful heavy duty gas turbines. With the onset of deregulation and consequent merchant power, combined cycle plants are now required to supply electrical power to the grid as and when needed with consequent day/night and weekday/weekend cycling. Those merchant plants have to come on and off line with minimal notice and be run sometimes at partial loads. Even units which were originally designed for base load are all eventually forced to cycle as new more efficient power plants are built. Thus, substantial changes in basic HRSG design are needed to cope with these changes. Coincidentally, the types of service projected for USA HRSGs have been in effect in Europe for over two decades. For this reason, European HRSG manufacturers/operators have adopted cycling tolerant Vertical HRSGs based on designs which permit the tubes to expand/contract freely and independently of one another, as distinguished from the more rigid horizontal gas pass design. Thus, fatigue stresses related to load following swings are minimized. This is just an illustration of the specific features of the Vertical European HRSGs for minimizing damages due to cycling related fatigue stresses. Vertical HRSG design shall be considered not only in terms of smaller footprint, but also as a solution to cycling related problems. As generally recognized, the cycling criterion is an integral part of HRSG design. This paper presents solutions to HRSG design issues for cycling tolerant operation. It relates to published data on problems observed with cycling Horizontal HRSGs, and it describes how these problems can be overcome. Concepts, design features and calculation methods applied to cycling tolerant HRSGs are reviewed in detail. Vertical HRSGs have been criticized because of their need for circulation pumps. Interestingly, the need for such pumps was eliminated a decade ago, with the advent of natural circulation for Vertical HRSGs up to 1800 psia (124 bar A) operating pressure.

Performance Evaluation of an Integrated Solar Combined Cycle

2012 ◽  
Author(s):  
Collins O. Ojo ◽  
Damien Pont ◽  
Enrico Conte ◽  
Richard Carroni
Keyword(s):  
Solar Energy ◽  
Capital Investment ◽  
Power Plants ◽  
Solar Power ◽  
Combined Cycle ◽  
Electricity Production ◽  
Water Steam ◽  
Plant Operator ◽  
Central Receiver ◽  
Solar Field

The integration of steam from a central-receiver solar field into a combined cycle power plant (CCPP) provides an option to convert solar energy into electricity at the highest possible efficiency, because of the high pressure and temperature conditions of the solar steam, and at the lowest capital investment, because the water-steam cycle of the CCPP is in shared use with the solar field. From the operational point of view, the plant operator has the option to compensate the variability of the solar energy with fossil fuel electricity production, to use the solar energy to save fuel and to boost the plant power output, while reducing the environmental footprint of the plant operation. Alstom is able to integrate very large amounts of solar energy in its new combined-cycle power plants, in the range of the largest solar field ever built (Ivanpah Solar Power Facility, California, 3 units, total 392 MWel). The performance potential of such integration is analyzed both at base load and at part load operation of the plant. Additionally, the potential for solar retrofit of existing combined-cycle power plants is assessed. In this case, other types of concentrating solar power technologies than central receiver (linear Fresnel and trough) may be best suited to the specific conditions. Alstom is able to integrate any of these technologies into existing combined-cycle power plants.

scholarly journals Thermo-economic Assessment of the first Integrated Solar Combined Cycle System of Hassi R’mel

Mechanika ◽  
2020 ◽  
Vol 26 (3) ◽  
pp. 242-251
Author(s):  
M. AMANI ◽  
A. SMAILI ◽  
A. GHENAIET
Keyword(s):  
Thermal Efficiency ◽  
Environmental Effect ◽  
Power Plants ◽  
Economic Assessment ◽  
Combined Cycle ◽  
Electricity Production ◽  
Fuel Saving ◽  
Electricity Cost ◽  
Cycle System ◽  
Solar Electricity

The aim of this study is the thermo-economic assessments of an integrated solar combined cycle (ISCC) system, in terms of thermal efficiency, electricity production and levelized electricity cost (LCOE). During the day light the power plant operates as an ISCC and operates as a conventional combined cycle (CC) during the night or cloudy days. In one hand the obtained results show that at the design point the solar electricity ratio may reach about 17 % and the global thermal efficiency 63 %, leading to lower fuel consumption and carbon emission. On the other hand, the economic assessment depicts that LCOE may reach 0.0222 $/kWh, which is about 28 % higher than that of (CC) power plants. Furthermore, by introducing the environmental effect LCOE becomes equal to 0.0272 $/kWh which is higher. Therefore, the annual solar contribution relatively to this ISCC installation site will allow about 18.45 million $ of fuel saving, avoiding emission of 0.89 million ton of CO2 over 30 years operation.

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.

scholarly journals The Effect of Ambient Temperature on Electric Power Generation in Natural Gas Combined Cycle Power Plant: A Case Study

2018 ◽  
Author(s):  
Günnur Şen ◽  
Mustafa Nil ◽  
Hayati Mamur ◽  
Halit Doğan ◽  
Mustafa Karamolla ◽  
...  
Keyword(s):  
Power Plant ◽  
Natural Gas ◽  
Ambient Temperature ◽  
Power Plants ◽  
Electric Energy ◽  
Combined Cycle ◽  
Electricity Production ◽  
Air Cooling ◽  
Seasonal Temperature ◽  
Natural Gas Combined Cycle

Natural gas combined cycle power plants (CCPPs) are widely used to meet peak loads in electric energy production. Continuous monitoring of the output electrical power of CCPPs is a requirement for power performance. In this study, the role of ambient temperature change having the greatest effect on electric production is investigated for a natural gas CCPP. The plant has generated electricity for fourteen years and setup at 240 MW in Aliağa, İzmir, Turkey. Depending on the seasonal temperature changes, the study data were obtained from each gas turbine (GT), steam turbine (ST) and combined cycle blocks (CCBs) in the ambient temperature range of 8-23°C. It has been found that decreases of the electric energy in the GTs because of the temperature increase and indirectly diminishes of the electricity production in the STs. As a result, the efficiency of each GT, ST and CCB reduced, although the quantity of fuel consumed by the controllers in the plant was decreased. As a result of this data, it has been recommended and applied that additional precautions have been taken for the power plant to bring the air entering the combustion chamber to ideal conditions and necessary air cooling systems have been installed.

Performance Optimization of Advanced Power Plants Based on Fossil Fuel Decarbonization Technologies

2007 ◽  
Author(s):  
Marco Gambini ◽  
Michela Vellini
Keyword(s):  
Power Plant ◽  
Natural Gas ◽  
Partial Oxidation ◽  
Performance Optimization ◽  
Power Plants ◽  
Fossil Fuel ◽  
H2 Production ◽  
Combined Cycle ◽  
Electricity Production ◽  
Percentage Points

In this paper two options for H2 production, by means of fossil fuels, are presented and their performances are evaluated when they are integrated with advanced H2/air cycles. In this investigation two different schemes have been analyzed: an advanced combined cycle power plant (CC) and a new advanced mixed cycle power plant (AMC). The two methods for producing H2 are as follows: • partial oxidation of methane; • gasification of coal. These hydrogen production plants require material and energetic integrations with the power section and the best interconnections must be investigated in order to obtain good overall performance. With reference to thermodynamic and economic performance, significant comparisons have been made between the above mentioned reference plants. An efficiency decrease and an increase in the cost of electricity have been obtained when power plants are equipped with a fossil fuel decarbonization section. The main results of the performed investigation are quite variable among the different H2 production technologies here considered: the efficiency decreases in a range of 5.5 percentage points to nearly 10 for the partial oxidation of the natural gas and in a range of 6.2–6.4 percentage points for the coal gasification. The electricity production cost increases in a range of about 33–37% for the first option and in a range of about 24–32% for the second one. The clean use of coal seems to have very good potentiality because, in comparison with natural gas decarbonisation, it allows lower energy penalizations (about 6 percentage points) and lower economic increases (about 24% for the CC).

scholarly journals Experimental Flame Front Characterisation in a Lean Premix Burner Operating with Syngas Simplified Model Fuel

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2377
Author(s):  
Edward Canepa ◽  
Alessandro Nilberto
Keyword(s):  
Flame Front ◽  
Gas Turbines ◽  
Power Plants ◽  
Large Scale ◽  
Combined Cycle ◽  
Turbulent Flames ◽  
Operating Conditions ◽  
Simplified Model ◽  
Fuel Ratio ◽  
Fluorescence Measurements

The recent growing attention to energy saving and environmental protection issues has brought attention to the possibility of exploiting syngas from gasification of biomass and coal for the firing of industrial plants included in the, so called, Integrated Gasification Combined Cycle power plants. In order to improve knowledge on the employ of syngas in lean premixed turbulent flames, a large scale swirl stabilized gas-turbine burner has been operated with a simplified model of H2 enriched syngas from coal gasification. The experimental campaign has been performed at atmospheric pressure, with operating conditions derived from scaling the real gas turbines. The results are reported here and consist of OH-PLIF (OH Planar Laser Induced Fluorescence) measurements, carried out at decreasing equivalence of air/fuel ratio conditions and analysed together with the mean aerodynamic characterisation of the burner flow field in isothermal conditions obtained through LDV (Laser Doppler Velocimetry) and PIV (Particle Image Velocimetry) measurements. The OH concentration distributions have been analysed statistically in order to obtain information about the location of the most reactive zones, and an algorithm has been applied to the data in order to identify the flame fronts. In addition, the flame front locations have been successively interpreted statistically to obtain information about their main features and their dependence on the air to fuel ratio behaviour.

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