Thermodynamic study of different configurations of gas-steam combined cycles employing intercooling and different means of cooling in topping cycle

2019 ◽  
Vol 162 ◽  
pp. 114249 ◽  
Author(s):  
Mayank Maheshwari ◽  
Onkar Singh
Keyword(s):  
Thermodynamic Study ◽  
Combined Cycles ◽  
Topping Cycle

Analysis of Intermediate Temperature Combined Cycles With a Carbon Dioxide Topping Cycle

2008 ◽  
Author(s):  
R. Chacartegui ◽  
D. Sa´nchez ◽  
F. Jime´nez-Espadafor ◽  
A. Mun˜oz ◽  
T. Sa´nchez
Keyword(s):  
Carbon Dioxide ◽  
Power Plant ◽  
Gas Turbine ◽  
High Efficiency ◽  
Solar Power ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Pressure Drops ◽  
Combined Cycles ◽  
Topping Cycle

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.

Performance and Economics of Advanced Energy Conversion Systems for Coal and Coal-Derived Fuels

1978 ◽  
Vol 100 (2) ◽  
pp. 252-259 ◽  
Author(s):  
J. C. Corman ◽  
G. R. Fox
Keyword(s):  
Energy Conversion ◽  
Power Plants ◽  
Technical Information ◽  
Steam Power ◽  
Energy Conversion Systems ◽  
Combined Cycles ◽  
Energy Conversion System ◽  
Open Cycle ◽  
Topping Cycle ◽  
Mhd System

The desire to establish an efficient Energy Conversion System to utilize the fossil fuel of the future—coal—has produced many candidate systems. A comparative technical/economic evaluation was performed on the seven most attractive advanced energy conversion systems. The evaluation maintains a cycle-to-cycle consistency in both performance and economic projections. The technical information base can be employed to make program decisions regarding the most attractive concept. A reference steam power plant was analyzed to the same detail and, under the same ground rules, was used as a comparison base. The power plants were all designed to utilize coal or coal-derived fuels and were targeted to meet an environmental standard. The systems evaluated were two advanced steam systems, a potassium topping cycle, a closed cycle helium system, two open cycle gas turbine combined cycles, and an open cycle MHD system.

Study of Pressurized Fluidized Bed Combustion Combined Cycles With Gas Turbine Topping Cycle

1992 ◽  
Author(s):  
D. Bohn ◽  
G. H. Dibelius ◽  
R. U. Pitt ◽  
R. Faatz ◽  
G. Cerri ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Gas Turbine ◽  
Energy Input ◽  
Fluidized Bed Combustion ◽  
High Pressure High Temperature ◽  
Combined Cycles ◽  
Topping Cycle ◽  
Pressurized Fluidized Bed Combustion ◽  
High Temperature Gas

Coal based combined cycles for efficient generation of electricity or cogeneration of thermal and mechanical (electrical) power can be realized making use of Pressurized Fluidized Bed Combustion (PFBC). A draw-back with respect to the efficiency, however, is imposed from the combustion system limiting the temperature to some 850°C. This threshold may be overcome by integrating a high pressure, high temperature gas turbine topping cycle into the process. In a first step, the high pressure, high temperature gas turbine is fired by natural gas, and the exhaust gas of the turbine is fed to the PFB combustor as an oxygen carrier. In a future advanced system, the fuel gas may be provided by an integrated coal gasification process. A basic reference case has been established based on commercially available gas turbine equipment, hot gas filtration systems as actually tested in various pilot installations, and on a conservative steam cycle component technology. With an ISO gas turbine inlet temperature of 1165°C and an overall compression ratio of 16 up to 30, the entire process yields a net efficiency of some 46% (LHV) and an overall power output of some 750 MW with the gaseous fuel making up for some 50% of the overall energy input. Both the efficiency and the power output have been found rather insensitive with respect to a variation of the overall compression ratio. However, for a non-intercooled compression, an increase of the maximum process pressure would allow for the energy input to be shifted towards coal (and to reduce the natural gas input), and in particular for an elevated PFB combustor pressure considered mandatory for compactness as well as for combustion efficiency including emissions. The numerous calculations for the design, the optimization and the prediction of part-load operation of complex systems are efficiently performed with a semi-implicit method, the results of which have been checked carefully against those of a more conventional sequential approach and found in good agreement.

Hybrid Dual-Fuel Combined Cycles for Small-Scale Applications With Internal Combustion Engines

2003 ◽  
Author(s):  
Miroslav P. Petrov ◽  
Thomas Stenhede ◽  
Andrew R. Martin ◽  
Laszlo Hunyadi
Keyword(s):  
Natural Gas ◽  
Power Plants ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Combined Cycle ◽  
Small Scale ◽  
Dual Fuel ◽  
Combustion Engines ◽  
Combined Cycles ◽  
Topping Cycle

Hybrid dual-fuel combined cycle power plants employ two or more different fuels (one of which is typically a solid fuel), utilized by two or more different prime movers with a thermal coupling in between. Major thermodynamic and economic advantages of hybrid combined cycle configurations have been pointed out by various authors in previous studies. The present investigation considers the performance of natural gas and biomass hybrid combined cycles in small scale, with an internal combustion engine as topping cycle and a steam boiler/turbine as bottoming cycle. A parametric analysis evaluates the impact of natural gas to biomass fuel energy ratio on the electrical efficiency of various hybrid configurations. Results show that significant performance improvements with standard technology can be achieved by these hybrid configurations when compared to the reference (two independent, single-fuel power plants at the relevant scales). Electrical efficiency of natural gas energy conversion can reach up to 57–58% LHV, while the efficiency attributed to the bottoming fuel rises with up to 4 percentage points. In contrast to hybrid cycles with gas turbines as topping cycle, hybrid configurations with internal combustion engines show remarkably similar performance independent of type of configuration, at low shares of natural gas fuel input.

Gas Turbine and MSW Boiler Hybrid Combined Cycles for High-Efficiency Power Production

2007 ◽  
Author(s):  
K. Qiu ◽  
A. C. S. Hayden
Keyword(s):  
Environmental Impact ◽  
Municipal Solid Waste ◽  
Gas Turbine ◽  
Energy Recovery ◽  
High Efficiency ◽  
Effective Means ◽  
Power Production ◽  
Combined Cycles ◽  
Topping Cycle ◽  
Waste Handling

The present work investigates gas turbine and municipal solid waste (MSW) incinerator hybrid combined cycles for power production. The aims are to achieve high efficiency for energy recovery from MSW while minimizing environmental impacts. In the combined cycles, the topping cycle consists of a gas turbine, while the bottoming cycle is a steam cycle, utilizing the heat from MSW combustion. Comprehensive simulations were made to analyze the viability of the combined cycles and their thermodynamic advantages over conventional incineration of MSW. The results showed that the hybrid combined cycles could offer dramatically higher efficiency for power production and provide practical solutions to problems typically associated with MSW. The environmental impact has been examined and it is shown that the combined cycles could provide an effective means of reducing greenhouse gas emissions. The capital and operating analyses indicate that the combined cycles for power production and waste handling are economically competitive.

Thermodynamic Study of Influence of Steam Injection in Combustion Chamber of Simple Gas/Steam Combined Cycle

2004 ◽  
Author(s):  
J. P. Yadav ◽  
Onkar Singh
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Steam Generator ◽  
Heat Recovery ◽  
Steam Injection ◽  
Combined Cycle ◽  
Thermodynamic Study ◽  
Specific Work ◽  
Heat Recovery Steam Generator ◽  
Topping Cycle

Steam injection is seen as one of the popular ways for power augmentation by number of turbine manufacturers and number of steam injected turbines such as Allison 501-K, GE LM 2500, and LM5000 are already in use. This paper presents the thermodynamic study of influence of steam injection in combustion chamber of topping cycle in a simple gas / steam combined cycle power plants upon the efficiency and specific work out put of topping cycle, bottoming cycle and combined cycle. The simple gas / steam combined cycle power plant configuration considered for the study has topping cycle gas turbine with film cooled stages employing air / steam as coolants and single pressure steam generation in the heat recovery steam generator (HRSG). Air for cooling has been bled out from compressor depending upon the requirement and the steam requirement as coolant is met from the steam generated in heat recovery steam generator (HRSG). Thermodynamic analysis of the simple combined cycle configuration considered has been completed with the variation in various parameters such as cycle pressure ratio, type of coolant used for gas turbine stages, mass fraction of the steam being injected in combustion chamber of topping cycle. Results obtained have been plotted suitably for the critical evaluation of influence of one parameter upon the other.

scholarly journals Optimizing a Pressurized Fluidized Bed Combustion Combined Cycle With Gas Turbine Topping Cycle

1993 ◽  
Author(s):  
D. Bohn ◽  
G. H. Dibelius ◽  
R. U. Pitt ◽  
R. Faatz ◽  
G. Cerri ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Coal Gasification ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Fluidized Bed Combustion ◽  
Steam Generation ◽  
Combined Cycles ◽  
Set Up ◽  
Topping Cycle ◽  
Pressurized Fluidized Bed Combustion

Combined Cycles for the generation of electricity or co-generation of heat and power with Pressurized Fluidized Bed Combustion (PFBC) of coal and a gas turbine topping cycle fired with a fuel suitable for gas turbines have been studied to set up optimum process parameters with respect to net efficiency, emissions including CO2, and keeping in mind the feasibility of the plant components. As a basic approach, natural gas has been considered as a fuel for the topping gas turbine. Net efficiencies up to 50% (LHV) are acheived. For the calculations, a Recursive Equality Constraint Quadratic Programming Method (RECQPM) is applied. The method is semi-implicit, i. e. the equations describing the process are solved using a non-linear equations system solver; the modular structure of the cycle is, however, made up for by programme modules set up for the relevant components/units. With the process layouts studied, the PFBC should be operated at a pressure level to allow for a compact design of the PFBC steam generator and the Hot Gas Clean-Up Unit (HGCU), and to take advantage of the pressure with respect to combustion efficiency, in-bed sulfur retention and NOx-reduction. The overall pressure ratio of the topping gas turbine, e. g. consisting of an LP-compressor plus a free running HP spool, and exhausting to the PFB combustor, should be in the range of 30. Further developments of gas turbine technology with respect to pressure ratio and turbine inlet temperature can be incorporated into the process and will be associated with an increase of overall efficiency. The heat to be extracted from the coal fired PFBC at the typical combustion temperature of 850°C allows for steam generation at conventional live steam and reheat temperatures (and pressures). The incorporation of advanced steam cycle parameters, as actually considered for pulverized coal fired boilers, would again increase the overall net efficiency of the cycle by some 5% with an increase of both the live steam and the reheat temperature from 540°C to 600°C. In contrast to conventional combined cycles with an unfired waste heat boiler for steam generation, the overall efficiency of the PFBC combined cycle with gas turbine topping cycle is only marginally affected by dual pressure steam cycle arrangements, except for very sophisticated and costly designs. To use gas from an integrated coal gasification unit rather than natural gas as a fuel for the topping gas turbine would result in an entirely coal based process. Due to the capability of the PFBC to burn residues of coal gasification and gas purification, this process, compared to pure Integrated Gasification Combined Cycles (IGCC), is less sensitive to the carbon conversion acheived. Even more, the raw gas purification might be simplified, and the process efficiency might be increased as a result of the sulphur removal to be acheived in the PFBC rather than in a raw gas sweetening process. Some preliminary findings for a process with an integrated partial gasification unit are discussed.

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