Split Stream Boilers for High-Temperature/High-Pressure Topping Steam Turbine Combined Cycles

1997 ◽  
Vol 119 (2) ◽  
pp. 385-394 ◽  
Author(s):  
I. G. Rice
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Steam Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Efficiency Gain ◽  
Side Stream ◽  
Combined Cycles ◽  
Gas Fuel ◽  
Cycle Efficiency

Research and development work on high-temperature and high-pressure (up to 1500°F TIT and 4500 psia) topping steam turbines and associated steam generators for steam power plants as well as combined cycle plants is being carried forward by DOE, EPRI, and independent companies. Aeroderivative gas turbines and heavy-duty gas turbines both will require exhaust gas supplementary firing to achieve high throttle temperatures. This paper presents an analysis and examples of a split stream boiler arrangement for high-temperature and high-pressure topping steam turbine combined cycles. A portion of the gas turbine exhaust flow is run in parallel with a conventional heat recovery steam generator (HRSG). This side stream is supplementary fired opposed to the current practice of full exhaust flow firing. Chemical fuel gas recuperation can be incorporated in the side stream as an option. A significant combined cycle efficiency gain of 2 to 4 percentage points can be realized using this split stream approach. Calculations and graphs show how the DOE goal of 60 percent combined cycle efficiency burning natural gas fuel can be exceeded. The boiler concept is equally applicable to the integrated coal gas fuel combined cycle (IGCC).

Split Stream Boilers for High Temperature/High Pressure Topping Steam Turbine Combined Cycles

1995 ◽  
Author(s):  
Ivan G. Rice
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Steam Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Efficiency Gain ◽  
Side Stream ◽  
Combined Cycles ◽  
Gas Fuel ◽  
Cycle Efficiency

Research and Development work on high temperature and high pressure (up to 1500 °F TIT and 4500 psia)1 topping steam turbines and associated steam generators for steam power plants as well as combined cycle plants is being carried forward by DOE, EPRI and independent companies. Aero Derivative gas turbines and Heavy Duty gas turbines both will require exhaust gas supplementary firing to achieve high throttle temperatures. This paper presents an analysis and examples of a split stream boiler arrangement for high temperature and high pressure topping steam turbine combined cycles. A portion of the gas turbine exhaust flow is run in parallel with a conventional heat recovery steam generator (HRSG). This side stream is supplementary fired opposed to current practice of full exhaust flow firing. Chemical fuel gas recuperation can be incorporated in the side stream as an option. A significant combined cycle efficiency gain of 2 to 4 percentage points can be realized using this split stream approach. Calculations and graphs show how the DOE goal of 60 % combined cycle efficiency burning natural gas fuel can be exceeded. The boiler concept is equally applicable to the integrated coal gas fuel combined cycle (IGCC).

Design, Part Load and Transient Operation of Combined Cycle Plants With Water Flashing

1995 ◽  
Author(s):  
P. J. Dechamps
Keyword(s):  
High Pressure ◽  
Steam Generator ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Vapour Phase ◽  
Pressure Level ◽  
Combined Cycle ◽  
Saturated Steam ◽  
Heat Recovery Steam Generator ◽  
Combined Cycles

The last decade has seen remarkable improvement in gas turbine based power generation technologies, with the increasing use of natural gas-fuelled combined cycle units in various regions of the world. The struggle for efficiency has produced highly complex combined cycle schemes based on heat recovery steam generators with multiple pressure levels and possibly reheat. As ever, the evolution of these schemes is the result of a technico-economic balance between the improvement in performance and the increased costs resulting from a more complex system. This paper looks from the thermodynamic point of view at some simplified combined cycle schemes based on the concept of water flashing. In such systems, high pressure saturated water is taken off the high pressure drum and flashed into a tank. The vapour phase is expanded as low pressure saturated steam or returned to the heat recovery steam generator for superheating, whilst the liquid phase is recirculated through the economizer. With only one drum and three or four heat exchangers in the boiler as in single pressure level systems, the plant might have a performance similar to that of a more complex dual pressure level system. Various configurations with flash tanks are studied based on commercially available 150 MW-class E-technology gas turbines and compared with classical multiple pressure level combined cycles. Reheat units are covered, both with flash tanks and as genuine combined cycles for comparison purposes. The design implications for the heat recovery steam generator in terms of heat transfer surfaces are emphasized. Off-design considerations are also covered for the flash based schemes, as well as transient performances of these schemes, because the simplicity of the flash systems compared to normal combined cycles significantly affects the dynamic behaviour of the plant.

Thermodynamic Optimization of a Combined Cycle Cogeneration Plant With Backpressure Steam Turbine

2006 ◽  
Author(s):  
K. Sarabchi ◽  
R. Akbarpour
Keyword(s):  
Steam Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Performance Criteria ◽  
Thermodynamic Optimization ◽  
Cogeneration Plant ◽  
Optimization Analysis ◽  
History Of ◽  
Cycle Efficiency ◽  
Good Agreement

Cogeneration heat and power plant has a long history of application in many types of industries, buildings etc, because of its benefits, such as environmental, energy and cost saving. A useful type of cogeneration plants is the combined cycle cogeneration plant. In this paper, thermodynamic optimization analysis for this type of plant (with backpressure steam turbine) and its performance criteria have been developed. It has been shown that the most efficient plant, for a target stack temperature could be achieved when the gas turbine and steam cycle are designed for maximum specific net work and cycle efficiency respectively. For validation purpose, some standard market gas turbines, which have maximum of 6% error with the basic thermodynamic model, have been chosen in this study. Also it has been shown that the results of optimization of cogeneration systems are in good agreement with those of standard turbines.

High Pressure Test Results of a Catalytic Combustor for Gas Turbine

1998 ◽  
Vol 120 (3) ◽  
pp. 509-513 ◽  
Author(s):  
T. Fujii ◽  
Y. Ozawa ◽  
S. Kikumoto ◽  
M. Sato ◽  
Y. Yuasa ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Catalytic Combustion ◽  
Combustion Process ◽  
Combined Cycle ◽  
Nox Emission ◽  
Test Results ◽  
Catalytic Combustor

Recently, the use of gas turbine systems, such as combined cycle and cogeneration systems, has gradually increased in the world. But even when a clean fuel such as LNG (liquefied natural gas) is used, thermal NOx is generated in the high temperature gas turbine combustion process. The NOx emission from gas turbines is controlled through selective catalytic reduction processes (SCR) in the Japanese electric industry. If catalytic combustion could be applied to the combustor of the gas turbine, it is expected to lower NOx emission more economically. Under such high temperature and high pressure conditions, as in the gas turbine, however, the durability of the catalyst is still insufficient. So it prevents the realization of a high temperature catalytic combustor. To overcome this difficulty, a catalytic combustor combined with premixed combustion for a 1300°C class gas turbine was developed. In this method, catalyst temperature is kept below 1000°C, and a lean premixed gas is injected into the catalytic combustion gas. As a result, the load on the catalyst is reduced and it is possible to prevent the catalyst deactivation. After a preliminary atmospheric test, the design of the combustort was modified and a high pressure combustion test was conducted. As a result, it was confirmed that NOx emission was below 10 ppm (at 16 percent O2) at a combustor outlet gas temperature of 1300°C and that the combustion efficiency was almost 100 percent. This paper presents the design features and test results of the combustor.

Using Hydrogen as Gas Turbine Fuel: Premixed Versus Diffusive Flame Combustors

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Matteo Gazzani ◽  
Paolo Chiesa ◽  
Emanuele Martelli ◽  
Stefano Sigali ◽  
Iarno Brunetti
Keyword(s):  
Gas Turbine ◽  
State Of The Art ◽  
Combined Cycle ◽  
Efficiency Gain ◽  
Degradation Mechanisms ◽  
Lean Premixed Combustion ◽  
Pressure Drops ◽  
Lean Premixed ◽  
Combined Cycles ◽  
Cycle Efficiency

This work aims at estimating the efficiency gain resulting from using lean premixed combustors in hydrogen-fired combined cycles with respect to diffusive flame combustors with significant inert dilution to limit NOx emissions. The analysis is carried out by considering a hydrogen-fired, specifically tailored gas turbine whose features are representative of a state-of-the-art natural gas–fired F-class gas turbine. The comparison between diffusion flame and lean premixed combustion is carried out considering nitrogen and steam as diluents, as well as different stoichiometric flame temperatures and pressure drops. Results show that the adoption of lean premixed combustors allows us to significantly reduce the efficiency decay resulting from inert dilution. Combined cycle efficiency slightly reduces from 58.5%–57.9% when combustor pressure drops vary in the range 3%–10%. Such efficiency values are comparatively higher than those achieved by diffusive flame combustor with inert dilution. Finally, the study investigated the effects of decreasing the maximum operating blade temperature so as to cope with possible degradation mechanisms induced by hydrogen combustion.

Adapting Gas Turbines to Zero Emission Oxy-Fuel Power Plants

2008 ◽  
Author(s):  
Roger E. Anderson ◽  
Scott MacAdam ◽  
Fermin Viteri ◽  
Daniel O. Davies ◽  
James P. Downs ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Natural Gas ◽  
Steam Turbine ◽  
Output Power ◽  
Gas Turbines ◽  
Power Plants ◽  
Low Pressure ◽  
Inlet Temperature ◽  
Zero Emission

Future power plants will require some type of carbon capture and storage (CCS) system to mitigate carbon dioxide (CO2) emissions. The most promising technologies for CCS are: oxy-fuel (O-F) combustion, pre-combustion capture, and post-combustion capture. This paper discusses the recent work conducted by Siemens Power Generation, Florida Turbine Technologies, Inc. (FTT) and Clean Energy Systems, Inc. (CES) in adapting high temperature gas turbines to use CES’s drive gases in high-efficiency O-F zero emission power plants (ZEPPs). CES’s O-F cycle features high-pressure combustion of fuel with oxygen (O2) in the presence of recycled coolant (water, steam or CO2) to produce drive gases composed predominantly of steam and CO2. This cycle provides the unique capability to capture nearly pure CO2 and trace by-products by simple condensation of the steam. An attractive O-F power cycle uses high, intermediate and low pressure turbines (HPT, IPT and LPT, respectively). The HPT may be based on either current commercial or advanced steam turbine technology. Low pressure steam turbine technology is readily applicable to the LPT. To achieve high efficiencies, an IPT is necessary and efficiency increases with inlet temperature. The high-temperature IPT’s necessitate advanced turbine materials and cooling technology. O-F plants have an abundance of water, cool steam ∼200°C (400°F) and CO2 that can be used as cooling fluids within the combustor and IPT systems. For the “First Generation” ZEPP, a General Electric J79 turbine, minus the compressor, to be driven directly by CES’s 170 MWt high-pressure oxy-fuel combustor (gas generator), has been adapted. A modest inlet gas temperature of 760°C (1400°F) was selected to eliminate the need for turbine cooling. The J79 turbine operating on natural gas delivers 32 MWe and incorporates a single-stage free-turbine that generates an additional 11 MWe. When an HPT and an LPT are added, the net output power (accounting for losses) becomes 60 MWe at 30% efficiency based on lower heating value (LHV), including the parasitic loads for O2 separation and compression and for CO2 capture and compression to 151.5 bar (2200 psia). For an inlet temperature of 927°C (1700°F), the nominal value, the net output power is 70 MWe at 34% efficiency (LHV). FTT and CES are evaluating a “Second Generation” IPT with a gas inlet temperature of 1260°C (2300°F). Predicted performance values for these plants incorporating the HPT, IPT and the LPT are: output power of approximately 100–200 MWe with an efficiency of 40 to 45%. The “Third Generation” IPT for 2015+ power plants will be based on the development of very high temperature turbines having an inlet temperature goal of 1760°C (3200°F). Recent DOE/CES studies project such plants will have LHV efficiencies in the 50% range for natural gas and HHV efficiencies near 40% for gasified coal.

scholarly journals High Pressure Test Results of a Catalytic Combustor for Gas Turbine

1996 ◽  
Author(s):  
T. Fujii ◽  
Y. Ozawa ◽  
S. Kikumoto ◽  
M. Sato ◽  
Y. Yuasa ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Catalytic Combustion ◽  
Combustion Process ◽  
Combined Cycle ◽  
Nox Emission ◽  
Test Results ◽  
Catalytic Combustor

Recently, use of gas turbine systems such as combined cycle and cogeneration systems has gradually increased in the world. But even when a clean fuel such as LNG (liquefied natural gas) is used, thermal NOx is generated in the high temperature gas turbine combustion process. The NOx emission from gas turbines is controlled through selective catalytic reduction processes (SCR) in the Japanese electric industry. If catalytic combustion could be applied to the combustor of the gas turbine, it is expected to lower NOx emission more economically. Under such high temperature and high pressure conditions as in the gas turbine, however, the durability of the catalyst is still insufficient. So it prevents the realization of a high temperature catalytic combustor. To overcome this difficulty, a catalytic combustor combined with premixed combustion for a 1300°C class gas turbine was developed. In this method, catalyst temperature is kept below 1000°C and a lean premixed gas is injected into the catalytic combustion gas. As a result, the load on the catalyst is reduced and it is possible to prevent the catalyst deactivation. After a preliminary atmospheric test, the design of the combustor was modified and a high pressure combustion test was conducted. As a result, it was confirmed that NOx emission was below 10ppm (at 16% O2) at a combustor outlet gas temperature of 1300°C and that the combustion efficiency was almost 100%. This paper presents the design features and test results of the combustor.

Conserving Energy by the Efficient Use of the Industrial Gas Turbine

1982 ◽  
Author(s):  
D. M. S. Lightbody
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Market Forces ◽  
Specific Work ◽  
Steam Turbines ◽  
The Uk ◽  
Industrial Gas Turbine ◽  
Cycle Efficiency

The paper covers the basic thermodynamics of the combined cycle concept and illustrates that energy conservation is possible by coupling the Joule and Rankine cycles. It discusses the optimisation of steam conditions and outlines the concept of the unfired combined cycle. “Carnot efficiency” and “pinch points” are shown to be important as is the concept of “specific work” as it relates to the gas turbine in arriving at the best overall cycle efficiencies. The importance of the efficiency characteristic of the steam turbine is emphasised and it is shown that this characteristic will determine the overall cycle efficiency. It is suggested that steam turbine manufacturers should design and develop steam turbines to match the advanced gas turbines available to-day and so enchance the overall efficiency which can presently be obtained from to-day’s combined cycle. Market forces will tend to bring this about as evidenced by the growing interest being shown in this concept both in the UK and Europe.

Performance Charateristics of Advanced Gas Turbine Cogeneration Power Plants

2005 ◽  
Author(s):  
Meherwan P. Boyce
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Firing Temperature ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Power Plants ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Air Filter ◽  
Cycle Efficiency

The performance analysis of the new generation of Gas Turbines in combined cycle operation is complex and presents new problems, which have to be addressed. The new units operate at very high turbine firing temperatures. Thus variation in this firing temperature significantly affects the performance and life of the components in the hot section of the turbine. The compressor pressure ratio is high which leads to a very narrow operation margin, thus making the turbine very susceptible to compressor fouling. The turbines are also very sensitive to backpressure exerted on them by the heat recovery steam generators. The pressure drop through the air filter also results in major deterioration of the performance of the turbine. The performance of the combined cycle is also dependent on the steam turbine performance. The steam turbine is dependent on the pressure, temperature, and flow generated in the heat recovery steam generator, which in turn is dependent on the turbine firing temperature, and the air mass flow through the gas turbine. It is obvious that the entire system is very intertwined and that deterioration of one component will lead to off-design operation of other components, which in most cases leads to overall drop in cycle efficiency. Thus, determining component performance and efficiency is the key to determining overall cycle efficiency. Thermodynamic modeling of the plant with individual component analysis is not only extremely important in optimizing the overall performance of the plant but in also determining life cycle considerations.

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