Cycle Gas Turbine Power Plant Research Articles

The impact of the new investments in combined cycle gas turbine power plants on the Italian electricity price

The paper measures the variation of the electricity price in Italy within the next 10 years due to the recent investment flow in combined cycle gas turbine (CCGT) power plants. It starts by investigating the possibility of decoupling gas and oil prices on the basis of hypotheses about the amount of existing resources and plausible technical substitutability assumptions of the latter with the former. In particular, it is supposed that, in the Italian market, natural gas will play a crucial role which oil has had in power generation. The price of electricity stemming from natural gas is then calculated taking into account the role of the power mix restructuring that derives from the CCGT power plants investments. Under reasonable assumptions, it is shown that a net reduction of at least 17% on the electric price is likely to be expected.

On existence of trends applicable to thermoeconomic optimisation of combined cycle gas turbine power plants

This paper aims at the influence of the nominal power on the design configuration of combined cycle gas turbine (CCGT) power plants. This is achieved by means of a thermoeconomic model aimed at the minimisation of the power plant cost. The present work starts with the establishment of trends in existing commercial gas turbines. Based on these, other trends are found for the design of the whole CCGT, leading to the assessment of the most suitable heat recovery steam generator type and the optimal design parameters. Finally, an analysis of the influence of fuel price on the design configuration is carried out. This serves two purposes: to observe the dependence of economic results with fuel prices and to determine whether fuel price variations might influence the previously established trends in the CCGT design.

Control Options for Load Rejection in a Three-Shaft Closed Cycle Gas Turbine Power Plant

An important issue to be addressed in power plants is the continued operation during load transients, such as load following and load rejection. It is inevitable that with new power plant technology, new control strategies will be required. One such technology investigated for commercial power plants is that of a three-shaft recuperative inter-cooled closed-loop Brayton cycle with a high-temperature gas-cooled nuclear reactor as the heat source and helium as coolant. Because of its unique configuration, the utilization of traditional power plant control strategies is limited. In order to address this, detailed cycle analyses were performed to identify new potential control strategies. The analyses were done using the Flownex thermohydraulic systems CFD simulation software since it is ideally suited for component and system integration. It also enables designers to simulate complex load scenarios and design-suitable controller algorithms. It was therefore possible to investigate control options for one of the most severe load control scenarios, i.e., that of full load rejection due to the loss of the grid power. This paper briefly describes the various control strategies investigated and presents details of the two strategies showing the most promising results with regard to load rejection.

A techno-economic analysis of the application of continuous staged-combustion and flameless oxidation to the combustor design in gas turbines

The impact of NO x reduction technologies upon a gas turbine power station has been investigated using the ECLIPSE process simulator. Technical, environmental and economic assessments were performed, based upon a model of the simple cycle gas turbine, fuelled by natural gas. The technologies assessed were: a) selective catalytic reduction (SCR); b) continuous staged air combustion (COSTAIR); and c) flameless oxidation method (FLOX). The SCR method produced a 90% reduction of NO x emissions, at an additional penalty to the electricity cost of 0.19–0.20 p/kWh, over the base case of simple cycle with standard combustor. The COSTAIR method reduced 80.4% of NO x emissions, at an additional electricity cost of 0.03–0.04 p/kWh, over the base case; but 0.16–0.17 p/kWh less than the SCR method at a slightly higher level of NO x emissions. The FLOX method generated 92.3% less of NO x emissions, at an additional electricity cost of 0.08–0.11 p/kWh, over the base case; but 0.09–0.11 p/kWh less than the SCR method at a lower level of NO x emissions. A sensitivity analysis of the Break-Even Selling Price (BESP) of electricity and the Specific Investment (SI) versus the cost of different burner systems shows that the SCR system had the highest values for BESP and SI; and the COSTAIR system had the lowest. The results show that the use of these non-standard burners could offer an effective method of reducing NO x emissions considerably for simple cycle gas turbine power plants with minimal effect on system capital cost and electricity selling price, and were also cheaper than using SCR.

Gas turbine emissions and environmental impact of efficiency boosting techniques

In this paper, environmental impact of gas turbine power generation equipment is reviewed and emissions sources are discussed. The types of pollutants in simple cycle gas turbine power plants and the associated air quality problems are compiled. Then, airborne pollutants which are generated in the combustion turbines are described and factors affecting emission formation are discussed. Also, the environmental impact of a number of efficiency boosting techniques including inlet air cooling and cogeneration is presented. It is concluded that environmental impact should be taken into account when economics of different efficiency boosting technologies is evaluated. Also, the conflicting issues of emission dependence on temperature need to be addressed in a broader perspective.

04/02476 Oxygen-enriched combustion in supercritical steam boilers: Horbaniuc, B. et al. Energy, 2004, 29, (3), 427–448

This paper describes a one-dimensional mathematical model that allows simulating the heat exchange in a steam generator working with water at supercritical pressure. The model has been developed in order to simulate the full and part load behaviour of heat recovery steam generators (HRSGs) of combined cycle gas turbine (CCGT) power plants. It takes into account the strong variation of some of the thermal and transport properties of fluids at supercritical pressure and discusses what parameters may be considered as constant along the heat exchanger.On the one hand, the model is useful because going supercritical is considered a way to further improve the efficiency of CCGT power plants and, on the other hand, because part load operation is the most usual operation mode in power plants.

Influence of the heat recovery steam generator design parameters on the thermoeconomic performances of combined cycle gas turbine power plants

This paper proposes a methodology to identify the most relevant design parameters that impact on the thermal efficiency and the economic results of combined cycle gas turbine power plants. The analysis focuses on the heat recovery steam generator (HRSG) design and more specifically on those operating parameters that have a direct influence on the economic results of the power plant. These results are obtained both at full and part load conditions using a dedicated code capable of simulating a wide number of different plant configurations. Two different thermoeconomic models aimed to select the best design point are proposed and compared: the first one analyzes the generating cost of the energy while the second one analyzes the annual cash flow of the plant. Their objective is to determine whether an increase in the investment in order to improve the thermal efficiency is worth from an economic point of view. Both models and the different HRSG configurations analysed are compared in the results section. Some parametric analysis show how the design parameters might be varied in order to improve the power plant efficiency or the economic results. Copyright © 2004 John Wiley & Sons, Ltd.

Thermoeconomic optimization of combined cycle gas turbine power plants using genetic algorithms

This paper shows a possible way to achieve a thermoeconomic optimization of combined cycle gas turbine (CCGT) power plants. The optimization has been done using a genetic algorithm, which has been tuned applying it to a single pressure CCGT power plant. Once tuned, the optimization algorithm has been used to evaluate more complex plants, with two and three pressure levels in the heat recovery steam generator (HRSG). The variables considered for the optimization were the thermodynamic parameters that establish the configuration of the HRSG. Two different objective functions are proposed: one minimizes the cost of production per unit of output and the other maximizes the annual cash flow. The results obtained with both functions are compared in order to find the better optimization strategy. The results show that it is possible to find an optimum for every design parameter. This optimum depends on the selected optimization strategy.

Allocating the Causes of Performance Deterioration in Combined Cycle Gas Turbine Plants

Abstract A method for defining which parts of a combined cycle gas turbine (CCGT) power plant are responsible for performance deviations is presented. When the overall performances deviate from their baseline values, application of the method allows the determination of the component(s) of the plant, responsible for this deviation. It is shown that simple differentiation approaches may lead to erroneous conclusions, because they do not reveal the nature of deviations for individual components. Contributions of individual components are then assessed by separating deviations due to permanent changes and deviations due to change of operating conditions. A generalized formulation is presented together with the way of implementing it. Test cases are given, to make clearer the ideas put forward in the proposed method.

Optimization of heat recovery steam generators for combined cycle gas turbine power plants

The heat recovery steam generator (HRSG) is one of the few components of combined cycle gas turbine power plants tailored for each specific application. Any change in its design would directly affect all the variables of the cycle and therefore the availability of tools for its optimization is of the greatest relevance. This paper presents a method for the optimization of the HRSG based on the application of influence coefficients. The influence coefficients are a useful mathematical tool in design optimization problems. They are obtained after solving the equations of the system through the Newton–Raphson method. The main advantage of the proposed method is that it permits a better understanding of the influence of the design parameters on the cycle performance. The study of the optimization of the distribution of the boiler area between its different components is presented as an example of the proposed technique.

Operational safety and post-maintenance gas leak detection in GE frame 9001FA gas turbines

The increased use of a natural-gas-fuelled combined cycle gas turbine and combined heat and power plants in recent years has been accompanied by the practice of constructing acoustic enclosures around the gas turbines for environmental reasons. This can increase the risk of an explosion if, for any reason, there is a build-up of flammable gas within the enclosure, since there can be a range of possible ignition sources. The UK Health and Safety Executive consider gas leaks within such enclosures to be foreseeable, especially following maintenance. The paper presents a review of operational safety and a leak detection method for the inspection and testing of flanged joints within the acoustic enclosures around GE 9001FA gas turbines, providing a practical step towards minimizing the risk of explosion due to fuel leakage.

Evaluation of advanced combined cycle power plants

AbstractThis report will analyse and evaluate the most recent and significant trends in combined cycle gas turbine (CCGT) power plant configurations. The various enhancements will be compared with the ‘simple’ gas turbine.The first trend, a gas turbine with reheat, cannot convert its better efficiency and higher output into a lower cost of electrical power. The additional investments required as well as increased maintenance costs will neutralize all the thermodynamic performance advantages.The second concept of cooling the turbine blades with steam puts very stringent requirements on the blade materials, the steam quality and the steam cooling system design. Closed-loop steam cooling of turbine blades offers cost advantages only if all its technical problems can be solved and the potential risks associated with the process can be eliminated through long demonstration programmes in the field.The third configuration, a gas turbine with a closed-loop combustion chamber cooling system, appears to be less pro...

Evaluation of Advanced Combined Cycle Power Plants

This report will analyse and evaluate the most recent and significant trends in combined cycle gas turbine (CCGT) power plant configurations. The various enhancements will be compared with the ‘simple’ gas turbine. The first trend, a gas turbine with reheat, cannot convert its better efficiency and higher output into a lower cost of electrical power. The additional investments required as well as increased maintenance costs will neutralize all the thermodynamic performance advantages. The second concept of cooling the turbine blades with steam puts very stringent requirements on the blade materials, the steam quality and the steam cooling system design. Closed-loop steam cooling of turbine blades offers cost advantages only if all its technical problems can be solved and the potential risks associated with the process can be eliminated through long demonstration programmes in the field. The third configuration, a gas turbine with a closed-loop combustion chamber cooling system, appears to be less problematic than the previous, steam-cooled turbine blades. In comparison with an open combustion chamber cooling system, this solution is more attractive due to better thermal performance and lower emissions. Either air or steam can be used as the cooling fluid.

ＬＮＧ火力発電所におけるＬＮＧ受入貯蔵・気化設備

Since 1969, many LNG receiving terminals have been constructed in Japan. This is in line with the Japanese policy of increasing the calorific value of city gas, and also changing the feedstock for thermal power plants to pollution-free LNG. In 1995, about 44 million tons of LNG were imported into Japan, and more than 70% of the LNG was used as fuel for power plants. Recently, advanced combined cycle gas-turbine power plants with higher thermal efficiency have been developed, and because LNG is more a suitable fuel for the plants than other fuels, the demand for LNG use in power plants is increasing. This paper presents a process outline of LNG receiving terminal for power plants and the main processing equipment, and mentions special consideration for the design of the LNG receiving terminal.

Combined Cycle Gas Turbine Power Plant With Coal Gasification and Solid Oxide Fuel Cell

The United States has extensive coal resources; thus, it is important to consider coal as a fuel for electric power production. This work presents a theoretical study of a novel high-efficiency coal-fired power plant. In the proposed combined cycle power plant, the Conoco coal gasification process is linked with solid oxide fuel cells (SOFC) and state-of-the-art gas turbines. The overall efficiency of such a plant can be around 60 percent, considering realistic heat, pressure, and other losses in the different components of the plant. If an additional steam turbine is incorporated, the overall efficiency can be increased to about 62 percent.

Thermodynamic Heating With Various Types of Cogeneration Plants and Heat Pumps

The thermodynamic heating method combines cogeneration power plants and heat pumps in order to maximize the heating energy that can be derived from a given amount of fuel. In doing this, unnecessary waste of primary energy and environmental damage can be prevented. In this paper, four cogeneration systems—combined cycle plants, steam and gas turbine power plants, and gas engines—and heat pump systems are investigated and compared with respect to fuel utilization for realistic site conditions. It is shown that the combined cycle cogeneration power plant is superior to the other three types of power plant.