scholarly journals Fuel-Flexible Combined Cycles for Utility Power and Cogeneration

1980 ◽  
Author(s):  
P. B. Roberts ◽  
T. E. Duffy ◽  
H. Schreiber

Two combustion turbine combined cycle power plants have been studied for performance and operating economics. Both power plants are in the size range that will be suitable for small utility application and use less than 106 GJ/hr (100 million Btu/hr). The Powerplant and Industrial Fuel Use Act of 1978 has exempted power plants of this size from the requirement to use coal. The first power plant is based on the Solar Turbines International (STI) Mars industrial gas turbine. The combined gas turbine/steam cycle is direct fired with No. 2 diesel fuel. A net plant efficiency of 39.7 percent (HHV) is obtained at the 11.56-mW growth rating of the Mars engine for a turbine rotor inlet temperature of 1331 K (1935 F). A total installed cost for the system is estimated to be within the band 545 to 660 $/kW. The second power plant is based on STI’s Centaur industrial gas turbine. The combined gas turbine/steam cycle is indirectly fired with solid fuel although it is intended that the installation can be initially fired with a liquid fuel. A net plant efficiency of 25.0 percent (HHV) is obtained burning Illinois No. 6 coal at a rating of 3.78 mW with a turbine inlet gas temperature of 1117 K (1550 F).

2020 ◽  
Vol 5 (12) ◽  
pp. 39-45
Author(s):  
Basharat Salim ◽  
Jamal Orfi ◽  
Shaker Saeed Alaqel

The proper utilization of all the available forms of energy resources has become imminent to meet the power requirement and energy demand in both the developed and developing countries of the world. Even though the emphasis is given to the renewable resources in most parts of the world, but fossil fuels will still remain the main resources of energy as these can meet both normal and peak demands. Saudi Arab has number of power plant based on natural gas and fuel that are spread in all its regions. These power plants have aeroderivative gas turbine units supplied by General Electric Company as main power producing units. These units work on dual fuel systems. These units work as simple gas turbine units to meat peak demands and as part of combined cycle otherwise. The subject matter of this study is the performance of one of the units of a power plant situated near Riyadh city of Saudi Arab. This unit also works both as simple gas turbine unit and as a part of combined cycle power plant unit. A parametric based performance evaluation of the unit has been carried out to study both energetic and exergetic performance of the unit for both simple and combined cycle operation. Effect of compressor inlet temperature, turbine inlet temperature, pressure ratio of the compressor, the stage from which bleed off air have been taken and percentage of bleed off air from the compressor on the energetic and exergetic performance of the unit have been studied. The study reveals that all these parameters effect the performance of the unit in both modes of operation.


Author(s):  
J. H. Moore

Combined-cycle power plants have been built with the gas turbine, steam turbine, and generator connected end-to-end to form a machine having a single shaft. To date, these plants have utilized a nonreheat steam cycle and a single-casing steam turbine of conventional design, connected to the collector end of the generator through a flexible shaft coupling. A new design has been developed for application of an advanced gas turbine of higher rating and higher firing temperature and exhaust gas temperature with a reheat steam cycle. The gas turbine and steam turbine are fully integrated mechanically, with solid shaft couplings and a common thrust bearing. This paper describes the new machine, with emphasis on the steam turbine section where the elimination of the flexible coupling created a number of unusual design requirements. Significant benefits in reduced cost and reduced complexity of design, operation, and maintenance are achieved as a result of the integration of the machine and its control and auxiliary systems.


Author(s):  
Christian Engelbert ◽  
Joseph J. Fadok ◽  
Robert A. Fuller ◽  
Bernd Lueneburg

Driven by the requirements of the US electric power market, the suppliers of power plants are challenged to reconcile both plant efficiency and operating flexibility. It is also anticipated that the future market will require more power plants with increased power density by means of a single gas turbine based combined-cycle plant. Paramount for plant efficiency is a highly efficient gas turbine and a state-of-the-art bottoming cycle, which are well harmonized. Also, operating and dispatch flexibility requires a bottoming cycle that has fast start, shutdown and cycling capabilities to support daily start and stop cycles. In order to meet these requirements the author’s company is responding with the development of the single-shaft 1S.W501G combined-cycle power plant. This nominal 400MW class plant will be equipped with the highly efficient W501G gas turbine, hydrogen-cooled generator, single side exhausting KN steam turbine and a Benson™ once-through heat recovery steam generator (Benson™-OT HRSG). The single-shaft 1S.W501G design will allow the plant not only to be operated economically during periods of high demand, but also to compete in the traditional “one-hour-forward” trading market that is served today only by simple-cycle gas turbines. By designing the plant with fast-start capability, start-up emissions, fuel and water consumption will be dramatically reduced. This Reference Power Plant (RPP) therefore represents a logical step in the evolution of combined-cycle power plant designs. It combines both the experiences of the well-known 50Hz single-shaft 1S.V94.3A plant with the fast start plant features developed for the 2.W501F multi-shaft RPP. The paper will address results of the single-shaft 1S.W501G development program within the authors’ company.


Author(s):  
R. Tuccillo ◽  
G. Fontana ◽  
E. Jannelli

In this paper, a general analysis of combined gas-steam cycles for power plants firing with both hydrocarbons and coal derived gas is reported. The purpose of this paper is to study the influence on power plants performance of different kind of fuels and to evaluate the most significant parameters of both gas and combined cycle. Results are presented for plant overall efficiency and net specific work, steam to gas mass flow ratio, dimensionless gas turbine specific speed and diameter, CO2 emissions etc., as functions of gas cycle pressure ratio and of the combustion temperature. Furthermore, for an existing power plant with a 120 MW gas turbine, the authors try to establish in which measure the combined cycle characteristic parameters, the gas turbine operating conditions, and the heat recovery steam generator efficiency, are modified by using synthetic fuels of different composition and calorific value. The influence is also analyzed either of bottoming steam cycle saturation pressure or — in a dual pressure steam cycle — of dimensionless fraction of steam mass flow in high pressure stream. The acquired results seem to constitute useful information on the criteria for the optimal design of a new integrated coal gasification combined cycle (IGCC) power plant.


Author(s):  
P. Shukla ◽  
M. Izadi ◽  
P. Marzocca ◽  
D. K. Aidun

The objective of this paper is to evaluate methods to increase the efficiency of a gas turbine power plant. Advanced intercooled gas turbine power plants are quite efficient, efficiency reaching about 47%. The efficiency could be further increased by recovering wasted heat. The system under consideration includes an intercooled gas turbine. The heat is being wasted in the intercooler and a temperature drop happens at the exhaust. For the current system it will be shown that combining the gas cycle with steam cycle and removing the intercooler will increase the efficiency of the combined cycle power plant up to 60%. In combined cycles the efficiency depends greatly on the exhaust temperature of the gas turbine and the higher gas temperature leads to the higher efficiency of the steam cycle. The analysis shows that the latest gas turbines with the intercooler can be employed more efficiently in a combined cycle power application if the intercooler is removed from the system.


Author(s):  
Wancai Liu ◽  
Hui Zhang

Gas turbine is widely applied in power-generation field, especially combined gas-steam cycle. In this paper, the new scheme of steam turbine driving compressor is investigated aiming at the gas-steam combined cycle power plant. Under calculating the thermodynamic process, the new scheme is compared with the scheme of conventional gas-steam combined cycle, pointing its main merits and shortcomings. At the same time, two improved schemes of steam turbine driving compressor are discussed.


Author(s):  
James Spelling ◽  
Björn Laumert ◽  
Torsten Fransson

A dynamic simulation model of a hybrid solar gas-turbine power plant has been developed, allowing determination of its thermodynamic and economic performance. In order to examine optimum gas-turbine designs for hybrid solar power plants, multi-objective thermoeconomic analysis has been performed, with two conflicting objectives: minimum levelized electricity costs and minimum specific CO2 emissions. Optimum cycle conditions: pressure-ratio, receiver temperature, turbine inlet temperature and flow rate, have been identified for a 15 MWe gas-turbine under different degrees of solarization. At moderate solar shares, the hybrid solar gas-turbine concept was shown to provide significant water and CO2 savings with only a minor increase in the levelized electricity cost.


Author(s):  
R. Chacartegui ◽  
D. Sa´nchez ◽  
F. Jime´nez-Espadafor ◽  
A. Mun˜oz ◽  
T. Sa´nchez

The development of high efficiency solar power plants based on gas turbine technology presents two problems, both of them directly associated with the solar power plant receiver design and the power plant size: lower turbine intake temperature and higher pressure drops in heat exchangers than in a conventional gas turbine. To partially solve these problems, different configurations of combined cycles composed of a closed cycle carbon dioxide gas turbine as topping cycle have been analyzed. The main advantage of the Brayton carbon dioxide cycle is its high net shaft work to expansion work ratio, in the range of 0.7–0.85 at supercritical compressor intake pressures, which is very close to that of the Rankine cycle. This feature will reduce the negative effects of pressure drops and will be also very interesting for cycles with moderate turbine inlet temperature (800–1000 K). Intercooling and reheat options are also considered. Furthermore, different working fluids have been analyzed for the bottoming cycle, seeking the best performance of the combined cycle in the ranges of temperatures considered.


Author(s):  
Alberto Vannoni ◽  
Andrea Giugno ◽  
Alessandro Sorce

Abstract Renewable energy penetration is growing, due to the target of greenhouse-gas-emission reduction, even though fossil fuel-based technologies are still necessary in the current energy market scenario to provide reliable back-up power to stabilize the grid. Nevertheless, currently, an investment in such a kind of power plant might not be profitable enough, since some energy policies have led to a general decrease of both the average price of electricity and its variability; moreover, in several countries negative prices are reached on some sunny or windy days. Within this context, Combined Heat and Power systems appear not just as a fuel-efficient way to fulfill local thermal demand, but also as a sustainable way to maintain installed capacity able to support electricity grid reliability. Innovative solutions to increase both the efficiency and flexibility of those power plants, as well as careful evaluations of the economic context, are essential to ensure the sustainability of the economic investment in a fast-paced changing energy field. This study aims to evaluate the economic viability and environmental impact of an integrated solution of a cogenerative combined cycle gas turbine power plant with a flue gas condensing heat pump. Considering capital expenditure, heat demand, electricity price and its fluctuations during the whole system life, the sustainability of the investment is evaluated taking into account the uncertainties of economic scenarios and benchmarked against the integration of a cogenerative combined cycle gas turbine power plant with a Heat-Only Boiler.


2021 ◽  
Author(s):  
Takashi Nishiumi ◽  
Hirofumi Ohara ◽  
Kotaro Miyauchi ◽  
Sosuke Nakamura ◽  
Toshishige Ai ◽  
...  

Abstract In recent years, MHPS achieved a NET M501J gas turbine combined cycle (GTCC) efficiency in excess of 62% operating at 1,600°C, while maintaining NOx under 25ppm. Taking advantage of our gas turbine combustion design, development and operational experience, retrofits of earlier generation gas turbines have been successfully applied and will be described in this paper. One example of the latest J-Series technologies, a conventional pilot nozzle was changed to a premix type pilot nozzle for low emission. The technology was retrofitted to the existing F-Series gas turbines, which resulted in emission rates of lower than 9ppm NOx(15%O2) while maintaining the same Turbine Inlet Temperature (TIT: Average Gas Temperature at the exit of the transition piece). After performing retrofitting design, high pressure rig tests, the field test prior to commercial operation was conducted on January 2019. This paper describes the Ultra-Low NOx combustor design features, retrofit design, high pressure rig test and verification test results of the upgraded M501F gas turbine. In addition, it describes another upgrade of turbine to improve efficiency and of combustion control system to achieve low emissions. Furthermore it describes the trouble-free upgrade of seven (7) units, which was completed by utilizing MHPS integration capabilities, including handling all the design, construction and service work of the main equipment, plant and control systems.


Sign in / Sign up

Export Citation Format

Share Document