bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ceramic Stationary Gas Turbine Development Program — Seventh Annual Summary
Authors: Price Jeffrey , Jimenez Oscar , Parthasarathy Vijay , Miriyala Narendernath , Leroux Don 
Published: August 2014

The Ceramic Stationary Gas Turbine (CSGT) program is being performed under the sponsorship of the United States Department of Energy, Office of Industrial Technologies. The objective of the program is to improve the performance of stationary gas turbines in cogeneration by retrofitting uncooled ceramic components into the hot section of the engine. The replacement of previously cooled metallic hot section components with the uncooled ceramics enables improved thermal efficiency, increased output power, and reduced gas turbine emissions. This review summarizes the progress on Phase III of the program, which involves field testing of the ceramic components at cogeneration end user sites.
The Solar Centaur 50S engine, which operates a turbine rotor inlet temperature (TRIT) of 1010°C (1850°F), was selected for the developmental program. The program goals include an increase in the TRIT to 1121°C (2050°F), accompanied by increases in thermal efficiency and output power. This will be accomplished by the incorporation of ceramic first stage blades and nozzles, and a “hot wall” ceramic combustor liner. The performance improvements are attributable to the increase in TRIT and the reduction in cooling air requirements for the ceramic parts. The “hot wall” ceramic liners also enable a reduction in gas turbine emissions of NOx and CO.
The component design and material selection have been definitized for the ceramic blades, nozzles and combustor liners. Each of these ceramic component designs was successfully tested in short term engine tests in the Centaur 50S engine test cell facility at Solar. Based on their performance in a 100 hour cyclic in-house engine test, the ceramic components were approved for field testing. Oxidation of the ceramic components in the gas turbine environment dictated the need for environmental barrier coatings, which were optimized under the program. To date, six field installations of the CSGT Centaur 50S engine totaling over 14,000 hours of operation have been initiated under the program at two industrial cogeneration sites. An 8000 hour field demonstration of a low emission ceramic combustion system was initiated in August 1999. This paper briefly discusses the recent developmental efforts for the ceramic components, but focuses on the various field demonstrations.
Experimental and Theoretical Studies of a Novel Venturi LPP Combustor
Authors: Røkke Nils A. , Wilson Andrew J. W. 
Published: August 2014

A new gas turbine engine using a unique layout patented in Norway has a low emission combustion system under development. The gas generator uses entirely radial rotating components and employs a dual entry LP radial compressor, a radial HP compressor and a radial HP turbine. The power turbine is of a two stage axial design, coupled to an epicyclical gear embedded in the exhaust duct.
Several combustor concepts have been tested and evaluated during the development of the engine. The engine is targeted for marine, power generation and train propulsion. For the marine and train application liquid fuel operation is needed, thus the primary focus in the development has been for a lean premixed prevapourised system.
An interesting concept utilising two venturi premixers has been studied intensively. By utilising venturi premixers the following advantages can be achieved:
• Low overall pressure drop but high injector pressure drop and velocities in the mixing region (throat region)
• High shear forces and drag imposed on the droplets enhancing droplet shedding and evaporation
• Excellent emission behaviour at designated load conditions
Although these advantages can benefit gas turbine low emission combustion the challenges in using venturi premixers are:
• Venturis are susceptible to separation and thus flame stabilisation within the venturi which is detrimental
• Inlet flow disturbances enhance the tendency for separation in the venturis and must be minimised
Studies were launched to investigate a proposed combustor configuration. These studies included analytical studies, Computational Fluid Dynamics (CFD) calculations of isothermal and combusting flow inside the combustor together with rig tests at atmospheric, medium and full pressure. Finally engine tests within the full operating range were conducted with very favourable emission figures for Lean Premixed Prevapourised (LPP) operation. The system was capable of running at below 20 ppm Nox and CO, at elevated power for liquid fuel. Control of part load performance and emissions is by variable fuel staging of the two venturi stages. The paper highlights the features of the venturi combustor development and discusses the characteristics in terms of flow conditions and droplet motion, heat transfer, ignition delay time and emissions.
Thermodynamic Optimization of Reheat Gas Turbine Cycles Combined With Bottoming Cycles
Authors: Shnaid Isaac 
Published: August 2014

In this work, thermodynamic optimization of reheat gas turbine cycles (without intercooling and recuperative heat exchange) combined with bottoming cycles, is done. Thermodynamic conditions ensuring the combined cycle engine maximal specific work and thermal efficiency are formulated for a general case of arbitrary number of reheat stages with different inlet gas temperatures and isentropic efficiencies.
Parametric analyses show that application of reheat cycles brings significant improvement of gas turbine and combined cycle specific work and efficiency in comparison with a case of a simple cycle gas turbine.
Comparison of Gas Turbine Cooling With Dry Air, Humidified Air and Steam
Authors: Jordal Kristin , Torisson Tord 
Published: August 2014

In order to study the impact of using a gas turbine coolant other than compressed air, a comparison is made among various gas-turbine based power cycles: the simple-cycle gas turbine, the steam injected gas turbine, the combined cycle and the Humid Air Turbine (HAT) cycle. Depending on the cycle configuration, the coolant, which is compared to the air extracted from the compressor, is either steam or humidified air. The study is based on a modern, medium-sized industrial gas turbine (net power output in base configuration: 40 MW), in order to evaluate the possibilities of different redesign options of the cooling system.
It is found that steam cooling is a very efficient method of cooling; whereas, the possible benefits of humid air cooling are mainly obtained through the temperature decrease that is a result of the humidification process. Hence, for the intercooled HAT cycle, the benefit of cooling with humid air is smaller (∼0.2 percentage points increase in thermal efficiency) than for the HAT cycle without intercooler (∼0.5 percentage points increase in thermal efficiency). For the simple cycle, there is an increase in thermal efficiency of 0.8 percentage points when it is cooled with humid air.
A parameter variation shows that with more advanced cooling technologies and heat resistant materials, the benefit of cooling with steam or humid air, instead of with compressed air, is reduced for the HAT and combined cycles.
Dynamic Modelling of the Gasification Island of a Coal-Based IGCC
Authors: Nihart Raoul 
Published: August 2014

In developed countries, coal power plants are often used to work in part load and possibly to follow the demand. Consequently, the transient behaviour of these power plants is a very important issue. In integrated coal gasification combined cycles (IGCCs), the complex interactions between the different parts of the plant make the process behaviour difficult to predict.
This paper describes a non-linear simulation model of the gasification island. It comprises mainly a module for the gasifier reactor with water walls, two different ones for the convective and radiant syngas coolers, a raw gas / clean gas heat exchanger and a simple module for the gas treatment. This latter is simplified because it has only a small influence on the transients of the plant given its low inertia. All these modules have been introduced into a dynamic computational tool previously designed to simulate the transients of gas combined cycles (Dechamps, 1995). The computational code, called CCDYN (Combined Cycle DYNamics), is a modular and flexible code, each module being a main component (like a gasifier, a gas turbine, a heat exchanger, …) solving a set of transient equations.
This paper also presents some results and demonstrates the interest of such a modelling. As an example, the gasification island of a coal-based IGCC is modelled in the case of different coal feed properties and the influence on the syngas composition is illustrated. Another example is the evolution with time of the various temperatures in the system during a start-up procedure and a load variation.
The thermochemical and physical properties used in the models are extracted from Barin (1989), from Perry and Green (1984) and from Dechamps (1995).
Selection of Cycle Configurations for Combined Cycle Cogeneration Power Plants
Authors: Tawney Rattan , Ehman John , Brown Mona 
Published: August 2014

Power industry growth and deregulation are causing fundamental changes in the economics of power production and distribution. In order to remain competitive, power producers now seek to improve plant economics through cogeneration, the simultaneous generation of power and production of steam for process use. The majority of manufacturing processes are of a continuous type that require high flexibility for power and steam systems (i.e., require various flows and conditions of steam at various power production levels).
This paper focuses on several ranges of process steam flows and conditions in order to provide a basis for comparison of the most common cycle configurations in combined cycle applications. A non-reheat, advanced technology gas turbine combined cycle facility will be used as the reference plant. Plant design, cycle performance, and economics of each configuration will be evaluated based on requirements of flexibility and process steam flows. This paper will provide guidelines for selection of cycle configurations for cogeneration power plants that will maximize Return on Equity for the owner.
PEACES: A Program for the Economic Analysis of Combined Energy Systems
Authors: Roy-Aikins Joseph 
Published: August 2014

Industrial concerns, the world over, are embracing gas/steam turbine combined cycles and combined heat and power as means of meeting energy needs. The main reason is that the potential for energy savings is huge, due to the utilisation of waste heat as useful energy — the key to the excellent thermodynamic performance exhibited by combined energy systems. Excellent thermodynamic performance may not be matched by excellent economic performance, and in certain cases it may not be economical to choose a combined energy system over a mix of supply from conventional plants. The factors governing the economics of combined energy are numerous, though a few are decisive. In choosing a plant for a given duty, an economic assessment of life-cycle costs should be carried out for candidate plants, to arrive at the most economically viable investment proposal, among alternatives.
With this in mind, a computer program PEACES was developed to aid the appraisal of energy investment proposals based on combined energy systems. The economic model on which the program was structured is described in this paper. A case study is carried out, where the software was used at arriving at the most economically viable solution for meeting the energy needs at an industrial site.
Set-Up of an Adaptive Method for the Diagnosis of Gas Turbine Operating State by Using Test-Bench Measurements
Authors: Bettocchi R. , Spina P. R. , Benvenuti E. 
Published: August 2014

The paper presents an application in the field of a method for the analysis of the gas turbine operating state, which uses the Cycle-Deck developed by the gas turbine manufacturer and the measurements taken by means of the standard machine instrumentation.
The method is applied for diagnosing the operating state of a number of gas turbines in operation at the test-bench in order to check in the field the validity and applicability of the methodology.
Influence of Ambient Conditions on an Aeroderivative Gas Turbine Based Cogeneration Plant — A Comparison of Numerical Simulation With Field Performance Data
Authors: Carcasci Carlo , Facchini Bruno , Grillo Francesco 
Published: August 2014

Gas turbine performances are directly related to outside conditions. The use of gas turbines in combined gas-steam power plants, also applied to cogeneration, increases performance dependence by outside conditions, because plants boundary conditions become more complex.
In recent years, inlet air cooling systems have been introduced to control air temperature and humidity at compressor inlet resulting in an increase in plant power and efficiency.
In this paper, the dependence of outside conditions for an existing cogenerative plant, located in Tuscany (Italy), is studied. The plant is equipped with two GE-LM6000 aeroderivative gas-turbines coupled with a three pressure level heat recovery steam generator, cogenerative application being related to the industrial district. The ambient temperature has been found to be the most important factor affecting the plant performance, but relative air humidity variation also has considerable effects.
The field performance data are compared with a numerical simulation. The simulation results show a good agreement with the field performance data. The simulation allows evaluation of design and off-design plant performance and can become a useful tool to study the outside condition influence on power plant performance.
Design Implementation of the Intercooler System of the WR-21
Authors: Cabanos Phil A. 
Published: August 2014

This paper describes the design implementation of the Intercooler System of the WR-21 Intercooled Recuperated Gas Turbine Engine (ICR). The Intercooler System extracts heat from the gas exiting the Intermediate Pressure Compressor (IPC) by means of on-engine, air-to-liquid heat exchangers. The heat transfer liquid is 50/50 ethylene glycol/water (EG). The heat is carried out of the engine by the EG to an off-engine EG-to-seawater heat exchanger. The seawater ultimately dumps the heat into the sea. The ICR is designed primarily for ship application where space is at a premium. Three design innovations that provide solutions to operational and emergency problems, resulting in a compact off-engine skid assembly will be introduced.
1. A system design that will handle pump shut downs and allow engine operation while the intercooler is isolated (bypass mode) — without putting the liquid system outside the enclosure under pressure.
2. A reservoir that is vented to atmosphere, that is only about 130 gallons in volume, that provides make-up and allows flow of 800–1000 US gpm (3000–3785 l/min) without causing turbulence in the reservoir.
3. A device that removes slugs of air trapped in the system during initial fill-up and continually deaerates the system.
Development of High Tech and Increased Efficiency Retrofit Options for the GE MS3002 Gas Turbine
Authors: Coppola A. , Francini S. , Noera F. 
Published: August 2014

This paper deals with a new complete uprate for the after-market of the General Electric MS3002H/J/AT two-shaft gas turbine. The new version, called MS3002KHE, is being developed to increase cycle efficiency by a minimum of 8% over the existing JAT units.
After a brief introduction, marketing evaluations behind the selected target chosen are pointed out.
A description of the GT components which were focused to be uprated follows, with an explanation of all implemented development activities.
Energy Optimisation and Reduction of CO2-Emission on the North Sea Sleipner Gas Production Platform
Authors: Underbakke Harald , Jakobsen Jon 
Published: August 2014

There is increasing focus in the industry towards energy efficiency and reduction of CO2 emission. In Norway this has also been strengthened by the introduction of the CO2-tax which in most cases more than doubles the fuel cost. In the North Sea production platforms operated by Statoil there has been a continuing optimisation program to reduce amount of fuel and flare gas for many years.
Optimisation has been done in maintaining high efficiency in gas turbine power production, reducing especially gas compression power demand by simple modifications and process optimisation, and reduce flaring by operating procedures and simple modifications. This has on the Sleipner platforms led to reduction of fuel gas consumption by more than 15 % and flaring has been reduced by 90 %. The total reduction of CO2 to atmosphere from Sleipner field is some 250 000 tons CO2 per year. Many of these improvements would also have been justifiable without the CO2-tax. This paper describes the various fuel and flare reduction activities done on the Sleipner field and outlines some of the possible further improvements currently being considered.
Synchronous Response Estimation in Rotating Machinery
Authors: Maslen Eric H. , Sortore Christopher K. , Vázquez José A. , Knospe Carl R. 
Published: August 2014

Synchronous response estimation attempts to determine the forced response (displacement) of a rotor at critical points which cannot be measured directly. This type of prediction, if accurate and reliable, has broad potential use in the rotating machinery industry. Many machines have close clearance points on their shafts, such as seals, which can easily be damaged by excess vibration. Accurate estimates of the actual level of vibration at these points could usefully assist machine operators in troubleshooting and in protecting the equipment from expensive damage. This type of response information can be used both to generate less conservative alarm limits and, if magnetic bearings are available, to directly guide the bearing controllers in restricting the rotor motion at these critical points.
It is assumed that the disturbance forces acting upon the rotor are predominantly synchronous. The response estimate is constructed using the measurable response in conjunction with an estimator gain matrix derived from a model of the transmissibilites of the rotor system. A fundamental performance bound is established based on the single-speed set of measurements by bounding the response to the unmeasurable component of the disturbance force. Acknowledging that some model uncertainty will always exist, a robust performance analysis is developed using structured singular value (μ) analysis techniques. Assuming some reasonable levels of uncertainty for the model parameters (natural frequencies, modal dampings, mode shapes, bearing stiffnesses and dampings) the results of the estimator construction and analysis establish feasibility of the proposed estimation.
Two reference rotor models that are representative of industrially sized machines are used to demonstrate and evaluate the estimation. The unmeasurable response estimation errors consistently lie below 25 μm for the examples examined.
Robust Performance Analysis of Uncertain Magnetic Bearings
Authors: Namerikawa Toru , Fujita Masayuki 
Published: August 2014

This paper deals with uncertain model structures, model validation and robust performance analysis of active magnetic bearing systems.
The dynamics of active magnetic bearing systems are characterized by their instability and complex dynamics of rotor and electromagnets. One of the most critical problems of AMBs is a description of a complex behavior of the dynamics of electromagnets and their forces. The exact description of them is almost hopeless, some approximations and assumptions must be employed, and consequently a discrepancy between the real physical system and the nominal design model cannot be avoided. This discrepancy of the magnetic bearing systems is a serious problem of stability and performance. Hence feedback control is indispensable to stabilize the system, further the closed-loop systems of AMBs should have robustness for stability and performance against model uncertainties.
First we derive a nominal mathematical model of AMBs as a linear state-space model under some assumption and idealization, then we consider the discrepancy between the real physical systems and the obtained nominal design model. This discrepancy can be expressed as the structured uncertainties by Linear Fractional Transformation. These uncertainties include linearization error, parametric uncertainties, unmodeled dynamics, and gyroscopic effect. Then we set the interconnection structure which contains the above structurally represented uncertainties. Next we design a robust controller which achieves robust performance condition. Finally, we validate the interconnection structure with the nominal model and uncertainties, and analyze the robustness of stability and performance of the closed-loop system via the mixed structured singular value.
A Numerical Investigation of the Unsteady Flow in Centrifugal Stages
Authors: Peeters Martin , Sleiman Mohamad 
Published: August 2014

Computational Fluid Dynamics (CFD) has matured to the point where it can now be used effectively in impeller and diffuser design. The effective use of CFD for a complete centrifugal stage, however, still remains a challenge. The interaction between an impeller and its diffuser is not well understood and the level of modelling required to explain it is not really known. The goal of this paper is to present some results that can aid in this understanding. A numerical scheme is outlined that is capable of both steady and unsteady stage analysis. Results are presented for a stage consisting of an impeller and pipe diffuser using steady mixing plane analysis. Furthermore, unsteady results for a centrifugal stage consisting of an impeller and a vane diffuser are presented and compared to isolated steady analyses of each component.
The results indicate that centrifugal stage performance is not well predicted using steady analysis. Differences in both the diffuser static pressure rise and the impeller pressure ratio are significant and it may be concluded that steady analysis is too unreliable for centrifugal stage predictions. Unsteady results also captured an important interaction phenomenon observed experimentally.