scholarly journals Considerations for Gas Turbines and Their Initial Operating Experiences at El Convento

Author(s):  
O. H. Pfersdorff

When original negotiations are made for the presentation of a report regarding “initial operating data” or “operating results,” it is hoped that all factors will contribute toward useful information to enlighten and assist others in the same operating category. Oftentimes this is not completely accomplished in the alloted time. This paper is presented to set forth the initial operating experiences and results of two highly controlled gas-turbine units for power generation. The individual turbine arrangement, fuel systems, control systems, start-up and operating problems and a comparison of test and design data are stated. The future outlook for gas turbines in the Electricidad de Caracas system is discussed.

Author(s):  
Mirko Morini ◽  
Giovanni Cataldi ◽  
Michele Pinelli ◽  
Mauro Venturini

Start-up is an important aspect of gas turbine operation. In the last years plant operators have shown an ever increasing interest in this critical phase, with particular focus on start-up reliability and start-up time. Several issues should be considered in order to achieve optimal start-up behavior: operability issues (e.g. compressor aerodynamics, combustor light-off and light-around, shaft acceleration), impact of thermal stresses on cyclic life, proper sizing of external starting devices. Models for the simulation of gas turbine behavior during start-up are very useful both for the design of new gas turbines and for the analysis and improvement of engines already in operation. In this paper, a physics-based model for the simulation of the start-up phase of large-size single-shaft gas turbines is presented. The model is based on operating data fitting and covers machine operation from combustor light-off to compressor blow off valve closure. The model makes use of steady-state component characteristics, while dynamics is taken into account through shaft power balance. Special features are also included to properly model the effects of heat soakage, i.e. the dependence of the engine behavior on its thermal status before the start-up. The quality of the model has been proven by application to the gas turbine engine ALSTOM GT13E2 and by comparison between measured and simulated data.


Author(s):  
Samarth Jain ◽  
Soumya Roy ◽  
Abhishek Aggarwal ◽  
Dhruv Gupta ◽  
Vasu Kumar ◽  
...  

The art and science of gas turbine has traditionally seen a gradual and continuous change over the past few decades. Gas turbines are classified into impulse and reaction types and further into turbojet, turbofan, turboprop, after burning turbojet and micro gas turbine. These turbines find applications in airplanes, large scale industries etc. but these are less suitable for the small scale power generation units due to several factors. Micro gas turbines are set to play a significant role particularly in small-scale power generation using combined heat and power generation among all these types of turbines as the future of power generation lies in decentralised and distributed power generation systems. In the light of making use of the high temperature exhaust of a gas turbine, combined heat and power generation systems are being used to increase the power output and overall efficiency. Micro gas turbines are essentially single-stage, single-shaft and low pressure gas turbines whose capacity ranges from 30–150 KW. In comparison to the conventional turbines, micro gas turbines are compact and have low lubricating oil consumption leading to a simpler lube and sump oil system and because they have fewer rotating parts, this leads to lesser balancing problems. The analysis of micro gas turbines has shown that they are capable of meeting current emission standards of NOx and other pollutants. Even though the installation costs of micro gas turbines are high due to the complexity in adjusting to electrical grid frequency, still these distributed energy systems may prove to be more attractive in a competitive market to those seeking increased reliability as they empower these entities with the capacity of self-generation. The following text reviews the developments in the micro gas turbines with a special focus on the efficiency of its components such as the recuperator, the combustion chamber design and also explores the future prospects of the technology in terms of viability of its application in the automobile sector.


Author(s):  
Hany Bassily ◽  
John Wagner

Nonlinear time series concepts may be applied to assess the health condition of dynamic systems for which their operating data is neither Gaussian nor periodic. The principles of phase space geometry suit the dynamic behavior exhibited during transient and non-stationary operating modes. In this paper, two strategies are presented to evaluate the dynamic behavior of power generating natural gas turbines based on the phase space properties. Recurrence analysis allows methods to be developed that are suitable for many dynamic systems. The evaluation of extensive operating data for a simple cycle power generating gas turbine was performed to assess the health condition, and to evaluate the performance of equipment clusters in a power generation plant. The analytical results obtained from this implementation, along with the main conclusions drawn regarding the health condition of the machines, demonstrates the opportunity for system diagnostics.


Author(s):  
James C. Corman

Gas turbines have reached a point in their development where they are becoming the preferred choice for utility and industrial power generation applications. In the last decade, this power generation technology has evolved rapidly both in terms of unit rating and in performance. The successful commercialization of the “F” (2350F [1288C] class) machine is the most recent step in this evolution. Although more “F” technology has been a significant accomplishment, it must be viewed as just one step in the evolution of gas turbine power generation systems to advanced conditions. As this development trend continues, these power generation systems will be under increasing pressure to meet tighter emission standards and to accommodate lower-grade fuels. Active development programs are now in place to meet both of these challenges. Dry Low NOx (DLN) combustion systems on advanced gas turbines will permit operation at even higher temperatures while controlling emissions. An integrated gasification gas turbine combined cycle (IGCC) using low-grade fuels — coal, residual oil, and biomass — is now approaching commercial status. The technology base for continuing the development of these gas turbine power generation systems far into the future exists and/or is under development. The DOE sponsored Advanced Turbine System Program is a key element in the development and ultimate commercial demonstration of this Next Generation System.


Author(s):  
Elliot Sullivan-Lewis ◽  
Vincent McDonell

Lean-premixed gas turbines are now common devices for low emissions stationary power generation. By creating a homogeneous mixture of fuel and air upstream of the combustion chamber, temperature variations are reduced within the combustor, which reduces emissions of nitrogen oxides. However, by premixing fuel and air, a potentially flammable mixture is established in a part of the engine not designed to contain a flame. If the flame propagates upstream from the combustor (flashback), significant engine damage can result. While significant effort has been put into developing flashback resistant combustors, these combustors are only capable of preventing flashback during steady operation of the engine. Transient events (e.g., auto-ignition within the premixer and pressure spikes during ignition) can trigger flashback that cannot be prevented with even the best combustor design. In these cases, preventing engine damage requires designing premixers that will not allow a flame to be sustained. Experimental studies were conducted to determine under what conditions premixed flames of hydrogen and natural gas can be anchored in a simulated gas turbine premixer. Tests have been conducted at pressures up to 9 atm, temperatures up to 750 K, and freestream velocities between 20 and 100 m/s. Flames were anchored in the wakes of features typical of premixer passageways, including cylinders, steps, and airfoils. The results of this study have been used to develop an engineering tool that predicts under what conditions a flame will anchor, and can be used for development of flame anchoring resistant gas turbine premixers.


Author(s):  
Matti Malkamäki ◽  
Ahti Jaatinen-Värri ◽  
Antti Uusitalo ◽  
Aki Grönman ◽  
Juha Honkatukia ◽  
...  

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.


Author(s):  
A. Cavarzere ◽  
M. Venturini

The growing need to increase the competitiveness of industrial systems continuously requires a reduction of maintenance costs, without compromising safe plant operation. Therefore, forecasting the future behavior of a system allows planning maintenance actions and saving costs, because unexpected stops can be avoided. In this paper, four different methodologies are applied to predict gas turbine behavior over time: Linear and Non Linear Regression, One Parameter Double Exponential Smoothing, Baesyan Forecasting Method and Kalman Filter. The four methodologies are used to provide a prediction of the time when a performance limit will be exceeded in the future, as a function of the current trend of the considered parameter. The application considers different scenarios which may be representative of the trend over time of some significant parameters for gas turbines. Moreover, the Baesyan Forecasting Method, which allows the detection of discontinuities in time series, is also tested for predicting system behavior after two consecutive trends. The results presented in this paper aim to select the most suitable methodology that allows both trending and forecasting as a function of data trend over time, in order to predict time evolution of gas turbine characteristic parameters and to provide an estimate of the occurrence of a failure.


Author(s):  
Mark A. Paisley ◽  
Donald Anson

The Biomass Power Program of the US Department of Energy (DOE) has as a major goal the development of cost-competitive technologies for the production of power from renewable biomass crops. The gasification of biomass provides the potential to meet his goal by efficiently and economically producing a renewable source of a clean gaseous fuel suitable for use in high efficiency gas turbines. This paper discusses the development and first commercial demonstration of the Battelle high-throughput gasification process for power generation systems. Projected process economics are presented along with a description of current experimental operations coupling a gas turbine power generation system to the research scale gasifier and the process scaleup activities in Burlington, Vermont.


Author(s):  
Wolfgang Kappis ◽  
Stefan Florjancic ◽  
Uwe Ruedel

Market requirements for the heavy duty gas turbine power generation business have significantly changed over the last few years. With high gas prices in former times, all users have been mainly focusing on efficiency in addition to overall life cycle costs. Today individual countries see different requirements, which is easily explainable picking three typical trends. In the United States, with the exploitation of shale gas, gas prices are at a very low level. Hence, many gas turbines are used as base load engines, i.e. nearly constant loads for extended times. For these engines reliability is of main importance and efficiency somewhat less. In Japan gas prices are extremely high, and therefore the need for efficiency is significantly higher. Due to the challenge to partly replace nuclear plants, these engines as well are mainly intended for base load operation. In Europe, with the mid and long term carbon reduction strategy, heavy duty gas turbines is mainly used to compensate for intermittent renewable power generation. As a consequence, very high cyclic operation including fast and reliable start-up, very high loading gradients, including frequency response, and extended minimum and maximum operating ranges are required. Additionally, there are other features that are frequently requested. Fuel flexibility is a major demand, reaching from fuels of lower purity, i.e. with higher carbon (C2+), content up to possible combustion of gases generated by electrolysis (H2). Lifecycle optimization, as another important request, relies on new technologies for reconditioning, lifetime monitoring, and improved lifetime prediction methods. Out of Alstom’s recent research and development activities the following items are specifically addressed in this paper. Thermodynamic engine modelling and associated tasks are discussed, as well as the improvement and introduction of new operating concepts. Furthermore extended applications of design methodologies are shown. An additional focus is set ono improve emission behaviour understanding and increased fuel flexibility. Finally, some applications of the new technologies in Alstom products are given, indicating the focus on market requirements and customer care.


Author(s):  
M. Sato ◽  
T. Abe ◽  
T. Ninomiya ◽  
T. Nakata ◽  
T. Yoshine ◽  
...  

From the view point of future coal utilization technology for the thermal power generation systems, the coal gasification combined cycle system has drawn special interest recently. In the coal gasification combined cycle power generation system, it is necessary to develop a high temperature gas turbine combustor using a low-BTU gas (LBG) which has high thermal efficiency and low emissions. In Japan a development program of the coal gasification combined cycle power generation system has started in 1985 by the national government and Japanese electric companies. In this program, 1300°C class gas turbines will be developed. If the fuel gas cleaning system is a hot type, the coal gaseous fuel to be supplied to gas turbines will contain ammonia. Ammonia will be converted to nitric oxides in the combustion process in gas turbines. Therefore, low fuel-NOx combustion technology will be one of the most important research subjects. This paper describes low fuel-NOx combustion technology for 1300°C class gas turbine combustors using coal gaseous low-BTU fuel as well as combustion characteristics and carbon monoxide emission characteristics. Combustion tests were conducted using a full-scale combustor used for the 150 MW gas turbine at the atmospheric pressure. Furthermore, high pressure combustion tests were conducted using a half-scale combustor used for the 1 50 MW gas turbine.


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