A Fifty Percent Plus Efficiency Mid Range Advanced Cheng Cycle

2002 ◽  
Author(s):  
Albert L. C. Nelson ◽  
Vahid Vaezi ◽  
Dah Yu Cheng
Keyword(s):  
Energy Balance ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combined Cycle ◽  
Performance Characteristics ◽  
Simple Cycle ◽  
Cycle Performance ◽  
Heat Recovery Boiler ◽  
Inlet Temperature ◽  
Variable Load

Cheng Power Systems, Inc. following the successful Cheng Cycle development based on the Allison 501KH, is developing a 50%+ efficiency medium-power-range Advanced Cheng Cycle. The recent development work involved the selection of a candidate gas turbine which possesses the following attributes: (1) a single shaft, (2) advanced compressor and turbine aerodynamic design, and (3) F-Class firing temperature. The targeted results were a 30MW+ output and 50%+ efficient intermediate-load Advanced Cheng Cycle with the simple-cycle performance characteristics of quick startup and shutdown and a $/kW cost comparable to simple-cycle machines, but at a combined-cycle efficiency. A candidate engine was selected which has the following performance characteristics: a compressor pressure ratio of 18:1, a turbine inlet temperature of 1250°C, and a net efficiency of 35%. Cheng Power has a unique software program which predicts the energy balance at various ambient conditions. The program takes into account the massive cooling air flows incorporated into advanced gas turbines and the heat recovery boiler performance characteristics when developing our performance analyses. The uniqueness of the Cheng Cycle is that it selects a trajectory of steam-to-air ratios to maintain high efficiency for the entire operating range of the power system, while offering competitive efficiency, simple hardware, the possibility of retrofit, fast response to load change, and feasible cogeneration plant operations. The quick startup of the Advanced Cheng Cycle is suitable for variable load operation in the mid range, i.e. 8 to 10 hours per day. This paper provides the energy balance of the proposed plant and its variation with ambient temperature. The paper also addresses the emission characteristics of this engine, which provides low NOx and CO emissions at levels that satisfy most U.S. EPA requirements without SCR or any other add-on devices.

scholarly journals Parametric Study of Fuel Cell and Gas Turbine Combined Cycle Performance

1997 ◽  
Author(s):  
Dawn Stephenson ◽  
Ian Ritchey
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Solid Oxide ◽  
Simple Cycle ◽  
Cycle Performance ◽  
Oxide Fuel ◽  
Combined Cycles

A number of cycles have been proposed in which a solid oxide fuel cell is used as the topping cycle to a gas turbine, including those recently described by Beve et al. (1996). Such proposals frequently focus on the combination of particular gas turbines with particular fuel cells. In this paper, the development of more general models for a number of alternative cycles is described. These models incorporate variations of component performance with key cycle parameters such as gas turbine pressure ratio, fuel cell operating temperature and air flow. Parametric studies are conducted using these models to produce performance maps, giving overall cycle performance in terms of both gas turbine and fuel cell design point operating conditions. The location of potential gas turbine and fuel cell combinations on these maps is then used to identify which of these combinations are most likely to be appropriate for optimum efficiency and power output. It is well known, for example, that the design point of a gas turbine optimised for simple cycle performance is not generally optimal for combined cycle gas turbine performance. The same phenomenon may be observed in combined fuel cell and gas turbine cycles, where both the fuel cell and the gas turbine are likely to differ from those which would be selected for peak simple cycle efficiency. The implications of this for practical fuel cell and gas turbine combined cycles and for development targets for solid oxide fuel cells are discussed. Finally, a brief comparison of the economics of simple cycle fuel cells, simple cycle gas turbines and fuel cell and gas turbine combined cycles is presented, illustrating the benefits which could result.

Comparative Analysis of Off-Design Performance Characteristics of Single and Two Shaft Industrial Gas Turbines

2002 ◽  
Author(s):  
J. H. Kim ◽  
T. S. Kim ◽  
J. L. Sohn ◽  
S. T. Ro
Keyword(s):  
Gas Turbines ◽  
Combined Cycle ◽  
Performance Characteristics ◽  
Cycle Performance ◽  
Operating Characteristics ◽  
Exhaust Temperature ◽  
Operating Modes ◽  
Recovery Capacity ◽  
Industrial Gas Turbines ◽  
Component Models

Off-design steady performance and operating characteristics of single and two shaft gas turbines for electric power generation have been investigated comparatively. A set of balance equations has been derived based on validated component models. A simultaneous calculation scheme has been employed, which is flexible to various engine configurations. Part-load performance analyses of two commercial gas turbines have been carried out to compare operating characteristics between single and two shaft engines. The predicted performance characteristics of both engines coincide soundly with the manufacturer’s data and also correspond with the inherent characteristics of each configuration. The adoption of the VIGV modulation has been addressed in order to examine the possibility of leveling up the heat recovery capacity by maintaining a high turbine exhaust temperature (TET) when those gas turbines are used for combined cycle plants. Maintaining TET at its design value as far as the VIGV modulation allows has been simulated and it has been determined that the TET control is possible at up to 40% and 50% load in the single and two shaft engine, respectively. Combined cycle performances have also been investigated for two engine configurations in different operating modes. While the VIGV modulation produces a favorable influence over the combined cycle performance of the single shaft configuration, the two shaft engine does not appear to be effectively improved by the VIGV modulation since the degradation of gas turbine performance counteracts the advantage of the higher performance of the bottoming (steam turbine) cycle.

Evaluation of Design Performance of the Semi-Closed Oxy-Fuel Combustion Combined Cycle

2012 ◽  
Author(s):  
H. J. Yang ◽  
D. W. Kang ◽  
J. H. Ahn ◽  
T. S. Kim
Keyword(s):  
Co2 Capture ◽  
Gas Turbines ◽  
Fuel Combustion ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Design Parameters ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Separation Unit ◽  
Turbine Inlet

This study aims to present various design aspects and realizable performance of the natural gas fired semi-closed oxy-fuel combustion combined cycle (SCOC-CC). Design parameters of the cycle are set up on the basis of component technologies of today’s state-of-the-art gas turbines with a turbine inlet temperature between 1400°C and 1600°C. The most important part in the cycle analysis is the turbine cooling which affects the cycle performance considerably. A thermodynamic cooling model is introduced to predict the reasonable amount of turbine coolant to maintain the turbine blade temperature of the SCOC-CC at the levels of those of conventional gas turbines. Optimal pressure ratio ranges of the SCOC-CC for two different turbine inlet temperature levels are searched. The performance penalty due to the CO2 capture is examined. Also investigated are the influences of the purity of oxygen provided by the air separation unit on the cycle performance. A comparison with the conventional combined cycle adopting a post-combustion CO2 capture is carried out taking into account the relationship between performance and CO2 capture rate.

Evaluation of Design Performance of the Semi-Closed Oxy-Fuel Combustion Combined Cycle

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
H. J. Yang ◽  
D. W. Kang ◽  
J. H. Ahn ◽  
T. S. Kim
Keyword(s):  
Co2 Capture ◽  
Gas Turbines ◽  
Fuel Combustion ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Design Parameters ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Separation Unit ◽  
Turbine Inlet

This study aims to present various design aspects and realizable performance of the natural gas fired semi-closed oxy-fuel combustion combined cycle (SCOC-CC). The design parameters of the cycle are set up on the basis of the component technologies of today’s state-of-the-art gas turbines with a turbine inlet temperature between 1400 °C and 1600 °C. The most important part of the cycle analysis is the turbine cooling, which considerably affects the cycle performance. A thermodynamic cooling model is introduced in order to predict the reasonable amount of turbine coolant needed to maintain the turbine blade temperature of the SCOC-CC at the levels of those of conventional gas turbines. The optimal pressure ratio ranges of the SCOC-CC for two different turbine inlet temperature levels are researched. The performance penalty due to the CO2 capture is examined. The influences of the purity of the oxygen provided by the air separation unit on the cycle performance are also investigated. A comparison with the conventional combined cycle, adopting a postcombustion CO2 capture, is carried out, taking into account the relationship between the performance and the CO2 capture rate.

Part-Load Operation of Gas Turbines Induced by Co-Gasification of Coal and Biomass in an Integrated Gasification Combined Cycle Power Plant

2021 ◽  
Author(s):  
Silvia Ravelli
Keyword(s):  
Power Plant ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Inlet Guide Vane ◽  
Inlet Temperature ◽  
Fuel Quality ◽  
Integrated Gasification Combined Cycle ◽  
Part Load ◽  
Wide Range ◽  
Integrated Gasification

Abstract This study takes inspiration from a previous work focused on the simulations of the Willem-Alexander Centrale (WAC) power plant located in Buggenum (the Netherlands), based on integrated gasification combined cycle (IGCC) technology, under both design and off-design conditions. These latter included co-gasification of coal and biomass, in proportions of 30:70, in three different fuel mixtures. Any drop in the energy content of the coal/biomass blend, with respect to 100% coal, translated into a reduction in gas turbine (GT) firing temperature and load, according to the guidelines of WAC testing. Since the model was found to be accurate in comparison with operational data, here attention is drawn to the GT behavior. Hence part load strategies, such as fuel-only turbine inlet temperature (TIT) control and inlet guide vane (IGV) control, were investigated with the aim of maximizing the net electric efficiency (ηel) of the whole plant. This was done for different GT models from leading manufactures on a comparable size, in the range between 190–200 MW. The influence of fuel quality on overall ηel was discussed for three binary blends, over a wide range of lower heating value (LHV), while ensuring a concentration of H2 in the syngas below the limit of 30 vol%. IGV control was found to deliver the highest IGCC ηel combined with the lowest CO2 emission intensity, when compared not only to TIT control but also to turbine exhaust temperature control, which matches the spec for the selected GT engine. Thermoflex® was used to compute mass and energy balances in a steady environment thus neglecting dynamic aspects.

Ancillary Services Potential for Flexible Combined Cycles

2021 ◽  
Author(s):  
Alberto Vannoni ◽  
Jose Angel Garcia ◽  
Weimar Mantilla ◽  
Rafael Guedez ◽  
Alessandro Sorce
Keyword(s):  
Electricity Market ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combined Cycle ◽  
Ancillary Services ◽  
Ancillary Service ◽  
Spinning Reserve ◽  
Service Market ◽  
Partial Load ◽  
Ancillary Services Market

Abstract Combined Cycle Gas Turbines, CCGTs, are often considered as the bridging technology to a decarbonized energy system thanks to their high exploitation rate of the fuel energetic potential. At present time in most European countries, however, revenues from the electricity market on their own are insufficient to operate existing CCGTs profitably, also discouraging new investments and compromising the future of the technology. In addition to their high efficiency, CCGTs offer ancillary services in support of the operation of the grid such as spinning reserve and frequency control, thus any potential risk of plant decommissioning or reduced investments could translate into a risk for the well-functioning of the network. To ensure the reliability of the electricity system in a transition towards a higher share of renewables, the economic sustainability of CCGTs must be preserved, for which it becomes relevant to monetize properly the ancillary services provided. In this paper, an accurate statistical analysis was performed on the day-ahead, intra-day, ancillary service, and balancing markets for the whole Italian power-oriented CCGT fleet. The profitability of 45 real production units, spread among 6 market zones, was assessed on an hourly basis considering local temperature, specific plant layouts, and off-design performance. The assessment revealed that net income from the ancillary service market doubled, on average, the one from the day-ahead energy market. It was observed that to be competitive in the ancillary services market CCGTs are required to be more flexible in terms of ramp rates, minimum environmental loads, and partial load efficiencies. This paper explores how integrating a Heat Pump and a Thermal Energy Storage within a CCGT could allow improving its competitiveness in the ancillary services market, and thus its profitability, by means of implementing a model of optimal dispatch operating on the ancillary services market.

Three Spool High Efficiency Small Scale Gas Turbine Concept

2017 ◽  
Author(s):  
Matti Malkamäki ◽  
Ahti Jaatinen-Värri ◽  
Antti Uusitalo ◽  
Aki Grönman ◽  
Juha Honkatukia ◽  
...  
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Small Scale ◽  
Inlet Temperature ◽  
Substantial Impact ◽  
Electrical Efficiency ◽  
Partial Load ◽  
Reciprocating Engines

Decentralized electricity and heat production is a rising trend in small-scale industry. There is a tendency towards more distributed power generation. The decentralized power generation is also pushed forward by the policymakers. Reciprocating engines and gas turbines have an essential role in the global decentralized energy markets and improvements in their electrical efficiency have a substantial impact from the environmental and economic viewpoints. This paper introduces an intercooled and recuperated three stage, three-shaft gas turbine concept in 850 kW electric output range. The gas turbine is optimized for a realistic combination of the turbomachinery efficiencies, the turbine inlet temperature, the compressor specific speeds, the recuperation rate and the pressure ratio. The new gas turbine design is a natural development of the earlier two-spool gas turbine construction and it competes with the efficiencies achieved both with similar size reciprocating engines and large industrial gas turbines used in heat and power generation all over the world and manufactured in large production series. This paper presents a small-scale gas turbine process, which has a simulated electrical efficiency of 48% as well as thermal efficiency of 51% and can compete with reciprocating engines in terms of electrical efficiency at nominal and partial load conditions.

scholarly journals Pressure gain combustion advantage in land-based electric power generation

2017 ◽  
Vol 1 ◽  
pp. K4MD26 ◽  
Author(s):  
Seyfettin C. Gülen
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Heavy Duty ◽  
Quantum Leap ◽  
Pressure Gain Combustion ◽  
Industrial Gas Turbines ◽  
Plant Efficiency

AbstractThis article evaluates the improvement in gas turbine combined cycle power plant efficiency and output via pressure gain combustion (PGC). Ideal and real cycle calculations are provided for a rigorous assessment of PGC variants (e.g., detonation and deflagration) in a realistic power plant framework with advanced heavy-duty industrial gas turbines. It is shown that PGC is the single-most potent knob available to the designers for a quantum leap in combined cycle performance.

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.

Proof-Of-Concept of a Thermal Barrier Coated Titanium Cooling Layer for an Inside-Out Ceramic Turbine

2021 ◽  
Author(s):  
Antoine Gauvin-Verville ◽  
Patrick K. Dubois ◽  
Benoit Picard ◽  
Alexandre Landry-Blais ◽  
Jean-Sébastien Plante ◽  
...  
Keyword(s):  
Polymer Composite ◽  
Safety Factor ◽  
Gas Turbines ◽  
High Efficiency ◽  
Cooling Power ◽  
Thermal Barrier ◽  
Inlet Temperature ◽  
Turbine Stage ◽  
Minimum Safety Factor ◽  
Inside Out

Abstract Increasing turbine inlet temperature (TIT) of recuperated gas turbines would lead to simultaneously high efficiency and power density, making them prime candidates for low-emission aeronautics applications, such as hybrid-electric aircraft. The Inside-out Ceramic Turbine (ICT) architecture achieves high TIT by using compression-loaded monolithic ceramics. To resist inertial forces due to blade tip speed exceeding 450 m/s, the shroud of the ICT is made of carbon-polymer composite, wound around a metallic cooling ring. This paper demonstrates that it is beneficial to use a titanium alloy cooling ring with a thermal barrier coating (TBC), rather than nickel superalloys, for the interstitial cooling ring protecting the carbon-polymer from the hot combustion gases. A numerical Design of Experiments (DOE) analysis shows the design trade-offs between the minimum safety factor and the required cooling power for multiple geometries. An optimized high-pressure first turbine stage of a 500 kW microturbine concept using ceramic blades and a titanium cooling ring in an ICT configuration is presented. Its structural performance (minimum safety factor of 1.4) as well as its cooling losses (2% of turbine stage power) are evaluated. Finally, a 20 kW-scale prototype is tested at 300 m/s and a TIT of 1375 K during 4hrs to demonstrate the viability of the concept. Experiments show that the polymer composite was kept below its maximum safe operating temperature and components show no early signs of degradation.

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