scholarly journals Alternative Fuels for Gas Turbines

Author(s):  
R. W. Ball

The gas turbines owned and operated by utilities throughout the world burn expensive fuels and are under-utilised. Much research work has been done into burning cheaper, alternative fuels. The range of alternative fuels that are available is extensive and the gas turbine can be adapted to burn most of them. The adaptation process will cost the utility money, the pay back period for which depends on the utilisation of the modified plant. Modification of gas turbine plant to burn acceptable fuels can delay purchase of new plant. No major problems are envisaged in the modification of gas turbine plant operated in New Zealand.

Author(s):  
R. Yadav ◽  
P. Sreedhar Yadav

The major challenges before the design engineers of a gas turbine plant and its variants are the enhancement of power output, substantial reduction in NOx emission and improvement in plant thermal efficiency. There are various possibilities to achieve these objectives and humid air gas turbine cycle power plant is one of them. The present study deals with the thermodynamic study of humid air gas turbine cycle power plants based on first law. Using the modeling and governing equations, the parametric study has been carried out. The results obtained will be helpful in designing the humid air gas turbines, which are used as peaking units. The comparison of performance of humid air gas turbine cycle shows that it is superior to basic gas turbine cycle but inferior and more complex to steam injected cycle.


Author(s):  
G. E. Marin ◽  
B. M. Osipov ◽  
A. R. Akhmetshin

THE PURPOSE. The study is aimed at studying the effect of fuel gases of various component composition on the environmental performance of the GE 6FA gas turbine unit. Consider using hydrogen as primary sweat to minimize emissions and improve performance of the GE 6FA gas turbine. METHODS. To achieve this goal, the ASGRET (Automated system for gas-dynamic calculations of power turbomachines) software package was used. RESULTS. The article discusses promising directions for the utilization of CO2 using highly efficient technologies with further use or disposal. A mathematical model of a GE 6FA gas turbine unit, diagrams of changes in the main characteristics and the composition of emissions when operating on various types of fuel, including hydrogen, are presented. CONCLUSION. The studies carried out show that a change in the component composition of the gas affects the energy characteristics of the engine. The method for determining the quantitative composition of COx, NOx, SOx in the exhaust gases of a gas turbine plant is presented. The transition to the reserve fuel kerosene leads to an increase in the amount of emissions, which must be taken into account when designing systems for capturing harmful emissions with a dual-fuel fuel gas supply system. The use of hydrogen as a fuel for gas turbines allows to reduce not only the cost of fuel preparation, but also to minimize emissions and improve the performance of the gas turbine plant.


2000 ◽  
Vol 123 (2) ◽  
pp. 265-270 ◽  
Author(s):  
E. A. Khodak ◽  
G. A. Romakhova

At present high temperature, internally cooled gas turbines form the basis for the development of highly efficient plants for utility and industrial markets. Minimizing irreversibility of processes in all components of a gas turbine plant leads to greater plant efficiency. Turbine cooling, like all real processes, is an irreversible process and results in lost opportunity for producing work. Traditional tools based on the first and second laws of thermodynamics enable performance parameters of a plant to be evaluated, but they give no way of separating the losses due to cooling from the overall losses. This limitation arises from the fact that the two processes, expansion and cooling, go on simultaneously in the turbine. Part of the cooling losses are conventionally attributed to the turbine losses. This study was intended for the direct determination of lost work due to cooling. To this end, a cooled gas turbine plant has been treated as a work-producing thermodynamic system consisting of two systems that exchange heat with one another. The concepts of availability and exergy have been used in the analysis of such a system. The proposed approach is applicable to gas turbines with various types of cooling: open-air, closed-steam, and open-steam cooling. The open-air cooling technology has found the most wide application in current gas turbines. Using this type of cooling as an example, the potential of the developed method is shown. Losses and destructions of exergy in the conversion of the fuel exergy into work are illustrated by the exergy flow diagram.


1997 ◽  
Vol 119 (3) ◽  
pp. 565-567
Author(s):  
Q. Song ◽  
M. J. Grimble

The algorithm for a multivariable controller using neural network is based on a discrete-time fixed controller and the neural network provides a compensation signal to suppress the nonlinearity. The multivariable neural controller is easy to train and applied to an aircraft gas turbine plant.


Author(s):  
F. R. Spurrier

A gas-turbine engine employed as the main propulsion plant in a ship must satisfy design requirements which differ considerably from those for other turbine applications. The design objectives in a gas-turbine plant for application to naval vessels of medium displacement are discussed in this paper. Such vessels, notably escort types, have duty profile characteristics which demand relatively short periods of operation at maximum power, and long periods at small percentages of maximum power. Normal cruising power may be only 15 per cent of the maximum available but economy of operation must be assured at this condition. In this respect, such engines introduce problems which do not arise in commercial vessels or aircraft-machines, where most of the operating life is spent at high percentages of the maximum available power.


Author(s):  
D. H. Benn

Methods of mathematical analysis are reviewed for defining and numerically computing the reliability of warship propulsion systems. Experimental analysis is made of a twin-screw all-gas-turbine plant design for a small warship and the results are compared with computed figures previously published for a geared-steam-turbine plant. It is apparent that relatively simple arrangement of components in subsystems is an inherent advantage of the gas turbine plant from the reliability standpoint and that this type of plant has a potential for high reliability. The analysis was made possible by the availability of component MTBF figures taken from past experience. It is hoped that this will encourage users of marine propulsion equipment to compile and present additional reliability statistics and possibly complete reliability analyses of propulsion plants currently in service.


Author(s):  
Mario DeCorso ◽  
David L. Moen ◽  
Paul W. Pillsbury

Diffusion flame combustors have served the gas turbine industry well since the invention of jet engines in the 1930’s. They provided fuel flexibility and the diffusion flame process gave the designer many options. Recently for heavy-duty land gas turbines, the need to reduce NOx emissions has led to the introduction of premixed combustor designs (Dry Low NOx - DLN) that have reduced fuel flexibility, operating range and reliability. With the increasing use and availability of Exhaust Cleanup Systems (EXCLUS) such as SCR and CO reduction catalysts, new gas turbine plant schemes that use diffusion flame combustors are back in the picture. This paper proposes a number of technique combinations that could achieve low NOx targets using diffusion flame combustors.


Author(s):  
Maurice F. White

This paper discusses a program which has been developed for the prediction of steady state and transient performance of a gas turbine driven generator. The gas turbine plant was modelled using the component model principle and is based on the method for continuity of mass flow. The model requires the use of compressor and turbine characteristics together with curves for combustion efficiency. A number of simplifications are made in connecion with transient calculations. The influence of the machines physical volume on continuity of mass flow and effects of heat transfer between the gas and structural components are neglected. The model was used to investigate how component deterioration affects the important condition parameters during load transients and during rapid acceleration or deceleration. Fault conditions were simulated by manipulating the various efficiencies and loss factors for the different components in the machine. Many of the condition parameters that were investigated showed changes during acceleration which were considerably different from comparable changes in a fault free gas turbine.


Author(s):  
T. Schobeiri ◽  
H. Haselbacher

The design of modern gas turbines requires the predetermination of their dynamic behavior during transients of various kinds. This is especially true for air storage and closed cycle gas turbine plants. The present paper is an introduction to a computatational method which permits an accurate simulation of any gas turbine system. Starting with the conservation equations of aero/thermodynamics, the modular computer program COTRAN was developed, which calculates the transient behavior of individual components as well as of entire gas turbine systems. For example, it contains modules for compressors, turbines, combustion chambers, pipes etc. To demonstrate the effectiveness of COTRAN the shut-down tests of the air storage gas turbine plant Huntorf were simulated and results compared with experimental data. The agreement was found to be very good.


Author(s):  
K. Takeo ◽  
Y. Shimura

A new gas turbine, the IM5000, which has changed the image of a gas turbine plant in view of specific size and efficiency, has been developed. In 1980, Ishikawajima-Harima Heavy Industries Co., Ltd., completed the lineup of aircraft-derivative gas turbines ranging from 15,000 to 50,000 hp when the company developed two new models in the 20,000 to 25,000 hp class, the IM2000 and the IM2500. To establish high reliability of the power turbine, an extensive investigation of the rotor assembly was completed. Engine test runs were conducted to confirm blade vibratory stresses through the whole operating range. The stress levels thus obtained revealed far below the critical limit and no detrimental resonance would be expected. The same attempt was adopted on the IM2500 power turbine which was developed in 1980. Through these two engine operations, the measuring method of blade vibratory stresses by means of strain gauges was established. Besides analyses of the rotating parts, analyses and experimental testing have been carried out on the stationary parts.


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