scholarly journals User-Oriented Gas Turbine Research at KEMA

1996 ◽  
Author(s):  
R. A. Rooth
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
High Efficiency ◽  
Turbine Rotor ◽  
Combined Cycle ◽  
Rotor Blades ◽  
Electricity Production ◽  
Combustion Chambers ◽  
Power Stations

In the 80’s and early 90’s, in the Netherlands 11 combi blocks with prefitted gas turbines have been built. This repowering programme increased the efficiency of the units involved by several percentage points. Additionally, the commissioning of the five 335 MWe units at the Eems power station is in progress and plans exist for a farther seven 250 MW heat and power stations. This means that by 2002 the generating industry will be operating seventy-five gas turbines with a total gas turbine power of 5700 MWe. These data serve to illustrate mat gas turbines will be the workhorse of the Dutch generating industry in the coming decades, and that security of supply, efficiency, emissions and generating cost will to a large extent be determined by the gas turbine. However, the introduction of the gas turbine, driven by the possibility of high-efficiency electricity generation in e.g. combined cycle units, the increase in scale of the machines and the fact that they are increasingly being used in base load units have also led to problems and forced unavailability, as will be shown under goals of the project. The problems are related to creep, thermal stresses and fatigue of combustion chambers, turbine rotor blades, rotors etc. Apart from these problem areas, other subjects of interest are optimization of inlet air filtering and compressor cleaning. It is the Dutch Electricity Production industry who realized that a substantial R&D effort is necessary to solve those user related problems and formulated the execution of the target project Gas Turbines.

scholarly journals The KEMA Gas Turbines Target Project: Overview and Status

1995 ◽  
Author(s):  
R. A. Rooth
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Electricity Production ◽  
Combustion Chambers ◽  
Power Stations ◽  
Base Load ◽  
Production Industry

Recently, in the Netherlands a number of 11 combi blocks with prefitted gas turbines have been built. Additionally, there are preparations for five 335 MWe units at the Eems power station and plans for a further seven 250 MW heat and power stations. This means that by 2002 the generating industry will be operating seventy-five gas turbines with a total gas turbine power of 5700 MWe. These data serve to illustrate that gas turbines will be the workhorse of the Dutch generating industry in the coming decades, and that security of supply, efficiency, emissions and generating cost will to a large extent be determined by the gas turbine. However, the introduction of the gas turbine, the increase in scale of the machines and the fact that they are increasingly being used in base load units have also led to problems and forced unavailability. The problems are related to creep, thermal stresses and fatigue of combustion chambers, turbine rotor blades, rotors etc. Apart from these problem areas, other subjects of interest are optimization of inlet air filtering and compressor cleaning. It is the Dutch Electricity Production industry who realized that a substantial R&D effort is necessary to solve those user related problems and who formulated and ordered the execution of the target project Gas turbines

scholarly journals Potential Applications of Structural Ceramic Composites in Gas Turbines

1990 ◽  
Author(s):  
W. P. Parks ◽  
R. R. Ramey ◽  
D. C. Rawlins ◽  
J. R. Price ◽  
M. Van Roode
Keyword(s):  
Gas Turbines ◽  
Ceramic Composite ◽  
Coal Gasification ◽  
Turbine Rotor ◽  
Ceramic Composites ◽  
Combined Cycle ◽  
Rotor Blades ◽  
Structural Ceramic ◽  
Cycle Systems ◽  
Potential Applications

A Babcock and Wilcox - Solar Turbines Team has completed a program to assess the potential for structural ceramic composites in turbines for direct coal-fired or coal gasification environments. A review is made of the existing processes in direct coal firing, pressurized fluid bed combustors, and coal gasification combined cycle systems. Material requirements in these areas were also discussed. The program examined the state-of-the-art in ceramic composite materials. Utilization of ceramic composites in the turbine rotor blades and nozzle vanes would provide the most benefit. A research program designed to introduce ceramic composite components to these turbines was recommended.

Combined Heat and Power: Gas Turbine Operational Flexibility

2013 ◽  
Author(s):  
James DiCampli
Keyword(s):  
Gas Turbine ◽  
Urban Areas ◽  
Gas Turbines ◽  
Heat Recovery ◽  
National Fire Protection Association ◽  
Combined Heat And Power ◽  
Combined Cycle ◽  
Electricity Production ◽  
Exhaust Heat ◽  
Gas Fuel

Combined heat and power (CHP) is an application that utilizes the exhaust heat generated from a gas turbine and converts it into a useful energy source for heating & cooling, or additional electric generation in combined cycle configurations. Compared to simple-cycle plants with no heat recovery, CHP plants emit fewer greenhouse gasses and other emissions, while generating significantly more useful energy per unit of fuel consumed. Clean plants are easier to permit, build and operate. Because of these advantages, projections show CHP capacity is expected to double and account for 24% of global electricity production by 2030. An aeroderivative power plant has distinct advantages to meet CHP needs. These include high thermal efficiency, low cost, easy installation, proven reliability, compact design for urban areas, simple operation and maintenance, fuel flexibility, and full power generation in a very short time period. There has been extensive discussion and analyses on modifying purge requirements on cycling units for faster dispatch. The National Fire Protection Association (NFPA) has required an air purge of downstream systems prior to startup to preclude potentially flammable or explosive conditions. The auto ignition temperature of natural gas fuel is around 800°F. Experience has shown that if the exhaust duct contains sufficient concentrations of captured gas fuel, and is not purged, it can ignite immediately during light off causing extensive damage to downstream equipment. The NFPA Boiler and Combustion Systems Hazards Code Committee have developed new procedures to safely provide for a fast-start capability. The change in the code was issued in the 2011 Edition of NFPA 85 and titled the Combustion Turbine Purge Credit. For a cycling plant and hot start conditions, implementation of purge credit can reduce normal start-to-load by 15–30 minutes. Part of the time saving is the reduction of the purge time itself, and the rest is faster ramp rates due to a higher initial temperature and pressure in the heat recovery steam generator (HRSG). This paper details the technical analysis and implementation of the NFPA purge credit recommendations on GE Power and Water aeroderivative gas turbines. This includes the hardware changes, triple block and double vent valve system (or drain for liquid fuels), and software changes that include monitoring and alarms managed by the control system.

Gas Turbine Exhaust Expansion Joints, Diverter and Damper Designs for the New Generation of Higher Temperature, High Efficiency Gas Turbines

1989 ◽  
Author(s):  
Lothar Bachmann ◽  
W. Fred Koch
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combined Cycle ◽  
Operating Conditions ◽  
High Mass ◽  
Expansion Joints ◽  
Gas Turbine Exhaust ◽  
New Generation ◽  
Turbine Exhaust

The purpose of this paper is to update the industry on the evolutionary steps that have been taken to address higher requirements imposed on the new generation combined cycle gas turbine exhaust ducting expansion joints, diverter and damper systems. Since the more challenging applications are in the larger systems, we shall concentrate on sizes from nine (9) square meters up to forty (40) square meters in ducting cross sections. (Reference: General Electric Frame 5 through Frame 9 sizes.) Severe problems encountered in gas turbine applications for the subject equipment are mostly traceable to stress buckling caused by differential expansion of components, improper insulation, unsuitable or incompatible mechanical design of features, components or materials, or poor workmanship. Conventional power plant expansion joints or dampers are designed for entirely different operating conditions and should not be applied in gas turbine applications. The sharp transients during gas turbine start-up as well as the very high temperature and high mass-flow operation conditions require specific designs for gas turbine application.

Aerodynamic Design and Numerical Investigation on Overall Performance of a Micro Radial Turbine With Millimeter-Scale

2009 ◽  
Author(s):  
Lei Fu ◽  
Yan Shi ◽  
Qinghua Deng ◽  
Zhenping Feng
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Micro Gas Turbine ◽  
Radial Turbine ◽  
Overall Performance ◽  
Low Reynolds ◽  
Exit Mach Number ◽  
Installation Technology

For millimeter-scale microturbines, the principal challenge is to achieve a design scheme to meet the aerothermodynamics, geometry restriction, structural strength and component functionality requirements while in consideration of the applicable materials, realizable manufacturing and installation technology. This paper mainly presents numerical investigations on the aerothermodynamic design, geometrical design and overall performance prediction of a millimeter-scale radial turbine with rotor diameter of 10mm. Four kinds of turbine rotor profiles were designed, and they were compared with one another in order to select the suitable profile for the micro radial turbine. The leaving velocity loss in micro gas turbines was found to be a large source of inefficiency. The approach of refining the geometric structure of rotor blades and the profile of diffuser were adopted to reduce the exit Mach number thus improving the total-static efficiency. Different from general gas turbines, micro gas turbines are operated in low Reynolds numbers, 104∼105, which has significant effect on flow separation, heat transfer and laminar to turbulent flow transition. Based on the selected rotor profile, several micro gas turbine configurations with different tip clearances of 0.1mm, 0.2mm and 0.3mm, respectively; two different isothermal wall conditions; and two laminar-turbulent transition models were investigated to understand the particular influence of low Reynolds number. These influences on the overall performance of the micro gas turbine were analyzed in details. The results indicate that these configurations should be included and emphasized during the design process of the millimeter-scale micro radial turbines.

Comparison of Externally Fired and Internal Combustion Gas Turbines Using Biomass Fuel

2001 ◽  
Vol 123 (4) ◽  
pp. 291-296 ◽  
Author(s):  
Sandro B. Ferreira ◽  
Pericles Pilidis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Internal Combustion ◽  
Combined Cycle ◽  
Maintenance Cost ◽  
Combustion Gas ◽  
Exhaust Temperature ◽  
Exergetic Analysis ◽  
Main Components

There is a difference of opinion regarding the relative merits of gas turbines using biomass fuels. Some engineers believe that the internal combustion gas turbine coupled to a gasifier will give a higher efficiency than the externally fired gas turbine using pretreated biomass that is not gasified. Others believe the opposite. In this paper, a comparison between these schemes is made, within the framework of the Brazilian perspective. The exergetic analysis of four cycles is described. The first cycle is externally fired (EFGT), the second uses gasified biomass as fuel (BIG/GT), each of them with a combined cycle as a variant (EFGT/CC and BIG/GTCC). These four are then compared to the natural gas turbine cycles (NGT and NGT/CC) in order to evaluate the thermodynamic cost of using biomass. The comparison is carried out in terms of thermal efficiency and in terms of exergetic efficiency and exergy destruction in the main components. The present analysis shows that the EFGT is quite promising. When compared to the NGT cycle, the EFGT gas turbine shows poor efficiency, though this parameter practically equals that of the BIG/GT cycle. The use of a bottoming steam cycle changes the figures, and the EFGT/CC—due to its higher exhaust temperature—results in high efficiency compared to the BIG/GTCC. Its lower initial and maintenance cost may be an important attraction.

Performance and Cost Analysis of Advanced Gas Turbine Cycles With Precombustion CO2 Capture

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Stéphanie Hoffmann ◽  
Michael Bartlett ◽  
Matthias Finkenrath ◽  
Andrei Evulet ◽  
Tord Peter Ursin
Keyword(s):  
High Pressure ◽  
Power Plant ◽  
Natural Gas ◽  
Gas Turbine ◽  
Co2 Capture ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combined Cycle ◽  
Co2 Separation ◽  
The Cost

This paper presents the results of an evaluation of advanced combined cycle gas turbine plants with precombustion capture of CO2 from natural gas. In particular, the designs are carried out with the objectives of high efficiency, low capital cost, and low emissions of carbon dioxide to the atmosphere. The novel cycles introduced in this paper are comprised of a high-pressure syngas generation island, in which an air-blown partial oxidation reformer is used to generate syngas from natural gas, and a power island, in which a CO2-lean syngas is burnt in a large frame machine. In order to reduce the efficiency penalty of natural gas reforming, a significant effort is spent evaluating and optimizing alternatives to recover the heat released during the process. CO2 is removed from the shifted syngas using either CO2 absorbing solvents or a CO2 membrane. CO2 separation membranes, in particular, have the potential for considerable cost or energy savings compared with conventional solvent-based separation and benefit from the high-pressure level of the syngas generation island. A feasibility analysis and a cycle performance evaluation are carried out for large frame gas turbines such as the 9FB. Both short-term and long-term solutions have been investigated. An analysis of the cost of CO2 avoided is presented, including an evaluation of the cost of modifying the combined cycle due to CO2 separation. The paper describes a power plant reaching the performance targets of 50% net cycle efficiency and 80% CO2 capture, as well as the cost target of 30$ per ton of CO2 avoided (2006 Q1 basis). This paper indicates a development path to this power plant that minimizes technical risks by incremental implementation of new technology.

A Thermodynamic Analysis of Different Options to Break 60% Electric Efficiency in Combined Cycle Power Plants

2004 ◽  
Vol 126 (4) ◽  
pp. 770-785 ◽  
Author(s):  
Paolo Chiesa ◽  
Ennio Macchi
Keyword(s):  
Gas Turbine ◽  
Thermodynamic Analysis ◽  
Gas Turbines ◽  
Power Plants ◽  
Closed Loop ◽  
Open Loop ◽  
Combined Cycle ◽  
Rotor Blades ◽  
Air Cooling ◽  
Large Size

All major manufacturers of large size gas turbines are developing new techniques aimed at achieving net electric efficiency higher than 60% in combined cycle applications. An essential factor for this goal is the effective cooling of the hottest rows of the gas turbine. The present work investigates three different approaches to this problem: (i) the most conventional open-loop air cooling; (ii) the closed-loop steam cooling for vanes and rotor blades; (iii) the use of two independent closed-loop circuits: steam for stator vanes and air for rotor blades. Reference is made uniquely to large size, single shaft units and performance is estimated through an updated release of the thermodynamic code GS, developed at the Energy Department of Politecnico di Milano. A detailed presentation of the calculation method is given in the paper. Although many aspects (such as reliability, capital cost, environmental issues) which can affect gas turbine design were neglected, thermodynamic analysis showed that efficiency higher than 61% can be achieved in the frame of current, available technology.

scholarly journals Gas Turbine Topping Stage Based on Energy Exchangers: Process and Performance

1993 ◽  
Author(s):  
Erwin Zauner ◽  
Yau-Pin Chyou ◽  
Frederic Walraven ◽  
Rolf Althaus
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Operating Cost ◽  
Combined Cycle ◽  
Specific Power ◽  
Material Strength ◽  
Nox Emissions ◽  
Gas Temperature ◽  
And Performance

Power generation in gas turbines is facing three main challenges today: • Low pollution prescribed by legal requirements. • High efficiency to obtain low operating cost and low CO2 emissions. • High specific power output to obtain low product and installation cost. Unfortunately, some of these requirements are contradictory: high efficiency and specific power force the development towards higher temperatures and pressures which increase NOx emissions and intensify the cooling and material strength problems. A breakthrough can be achieved by applying an energy exchanger as a topping stage. Inherent advantages are the self-cooled cell-rotor which can be exposed to much higher gas temperature than a steady-flow turbine and a very short residence time at peak temperature which keeps NOx emissions under control. The basic idea has been proposed long time ago. Fundamental research has now led to a new energy exchanger concept. Key issues include symmetric pressure-wave processes, partial suppression of flow separation and fluid mixing, as well as quick afterburning in premixed mode. The concept has been proven in a laboratory-scale engine with very promising results. The application of an energy exchanger as a topping stage onto existing gas turbines would increase the efficiency by 17% (relative) and the power by 25%. Since the temperature level in the turbine remains unchanged, the performance improvement can also be fully utilized in combined cycle applications. This process indicates great potentials for developing advanced gas turbine systems as well as for retrofitting existing ones.

scholarly journals Mechanical and Process Design of the Flevo Power Station Conversion Project

1989 ◽  
Author(s):  
J. Feenstra ◽  
P. Kamminga
Keyword(s):  
The Netherlands ◽  
Gas Turbine ◽  
Process Design ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Power Station ◽  
Power Stations ◽  
The North

EPON operates a number of power stations in the north of the Netherlands. At some of these the forced-draught-fans have been replaced by gas turbines. Unit 3 of Flevo Power Station was the latest repowering project in the Netherlands. This paper gives a description of the most important points of the mechanical, and process design of the combined cycle unit and the influence of the gas turbine on the starting procedure.

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