95-GT-421 BLADING VIBRATION AND FAILURES IN GAS TURBINES PART D: CASE STUDIES

ABSTRACT The investigation of gas turbine blade failures requires an interdisciplinary approach calling for expertise in gas turbine design, operation and metallurgy. The object of this paper is to show, in the context of blading problems, the interrelationship between design, operation, maintenance, and the operational envelope. This paper presents case studies dealing with a variety of failure modes. The treatment focuses on practical troubleshooting of blading problems augmented, in some cases, by the use of analytical tools

Case Studies In Turbomachinery Operation And Maintenance Using Condition Monitoring.

LecturePg. 101-112With exceedingly high downtime costs and the need for efficient operation of turbo machinery, integrated condition monitoring, wherein a number of health parameters are analyzed, is becoming increasingly popular in process plants and in utilities. Most operational problems can be diagnosed by developing a correlation among several key operating parameters. A wide range of condition monitoring approaches are available and this paper shows how several approaches can be used in conjunction with one another to solve operational problems. Several case studies pertaining to gas and steam turbines and compressors are presented. A matrix of condition monitoring techniques is provided and case studies are presented. Finally, future trends in the area of condition monitoring are presented

GAS TURBINE PERFORMANCE DETERIORATION AND COMPRESSOR WASHING

TutorialThe privatization of utilities, intense competition in the petrochemical and gas distribution industries, coupled with increasing fuel costs, have created a strong incentive for gas turbine operators to minimize and control performance deterioration. The most significant deterioration problem faced by gas turbine operators is compressor fouling which is the focus of this paper. The effect of compressor fouling is a drop in airflow, pressure ratio and compressor efficiency, resulting in a rematching of the gas turbine and compressor and a drop in power output and thermal efficiency. This paper provides a comprehensive practical treatment of the causes, effects and control of fouling. Gas turbine inlet filtration, fouling mechanisms and compressor washing are also covered in detail. The major emphasis will be on the causes, effects detection and control of compressor fouling. The complexities and challenges of on-line washing of large output new gas turbines will also be covered. The treatment also applies to axial air compressors used in the hydrocarbon processing industry

Gas Turbine Blade Failures - Causes, Avoidance, And Troubleshooting.

Tutorialpg. 129-180With blading problems accounting for as many as 42 percent of the failures in gas turbines (Allianz, 1 978) and with its severe effect on plant availability, there is a pressing need for a unified treatment of the causes, failure modes, and troubleshooting to assist plant engineers in tackling blade failure problems. This paper provides a comprehensive practical treatment of the subject, taking into account the complex nature of blading problems, influence of the operating environment, design factors, and maintenance practices. Blade failure modes such as fatigue, environmental attack, creep, erosion, and embrittlement are addressed along with a synopsis of design tools to review blade reliability. Peripheral issues affecting blade integrity such as fuel and blade quality control are addressed. A blade failure troubleshooting chart is furnished to assist users in diagnosing common failure modes. The object of this paper is to show, in the context of blading problems, the interrelationship between design, operation, maintenance, and the operational envelope. Several case studies are presented dealing with a variety of failure modes. The treatment focuses on practical troubleshooting of blading problems augmented, in some cases, by the use of analytical tools. APPENDIX A provides applicable tools, rules of thumb, and formulae that can be used by gas turbine users for design review and troubleshooting

Industrial Gas Turbines

Short CourseThe course covers the new advanced technology gas turbines by outlining all the major components of gas turbines, such as axial flow compressors, axial flow turbines, and dry low NOx combustors. The components of a gas turbine will be addressed from a design, operation, and maintenance point of view as well as their effect on plant operation, plant availability, and reliability. Also covered will be the best practices in operating the new advanced technology gas turbines at variable loads obtaining best efficiencies with minimal down time

Gas Turbine Performance And Maintenance

TutorialProper maintenance and operating practices can significantly affect the level of performance degradation and thus, time between repairs or overhauls of a gas turbine. Understanding of performance characteristics of gas turbines helps proper applications, as well as driven and process equipment sizing. Proactive condition monitoring will allow the gas turbine operator to make intelligent service decisions based on the actual condition of the gas turbine rather than on fixed and calendar based maintenance intervals. Maintaining inlet air, fuel, and lube oil quality will further reduce gas turbine degradation and deterioration. This tutorial provides a discussion on performance characteristics and how performance degradation can be minimized. Recommendations are provided on how the operator can limit degradation and deterioration of the gas turbines through proper maintenance practices. The effects of water-washing and best washing practices are discussed. Emphasis is on the monitoring of gas turbine performance parameters to establish condition based maintenance practices

LNG Liquefaction Plants - Overview, Design & Operations: Short Course

Short Cours

LNG TURBOMACHINERY

TutorialThe International Liquefied Natural Gas (LNG) trade is expanding rapidly. Projects are being proposed worldwide to meet the industry forecasted growth rate of 12% by the end of the decade. LNG train designs in the coming years appear to fall within three classes, having nominal capacities of approximately 3.5, 5.0 and 8.0 MTPA (Million Tons Per Annum). These designs may co-exist in the coming years, as individual projects choose designs, which closely match their gas supplies, sales, and other logistical and economic constraints. The most critical components of a LNG liquefaction facility are the refrigeration compressors and their drivers which represent a significant expense and strongly influence overall plant performance and production efficiency. The refrigeration compressors themselves are challenging to design due to high Mach numbers, large volume flows, low inlet temperatures and complex sidestream flows. Drivers for these plants include gas turbines that range in size from 30 MW units to large Frame 9E gas turbines. Aeroderivative engines have also been recently introduced. This paper covers the design, application and implementation considerations pertaining to LNG plant drivers and compressors. The paper does not focus on any particular LNG process but addresses turbomachinery design and application aspects that are common to all processes. Topics cover key technical design issues and complexities involved in the turbomachinery selection, aeromechanical design, testing and implementation. The paper attempts to highlight the practical design compromises that have to be made to obtain a robust solution from a mechanical and aerodynamic standpoint

Gas Turbine Degradation

TutorialThere is a strong incentive for gas turbine operators to minimize and control performance degradation, as this directly affects profitability. The area of gas turbine recoverable and non-recoverable performance degradation will be comprehensively treated in this tutorial. Deterioration mechanisms including compressor and turbine fouling, erosion, increased clearances, and seal distress will be covered along with their manifestations, rules of thumb, and mitigation approaches. The treatment will deal with simple cycle gas turbines in power generation and mechanical drive applications and will also address the impact of performance deterioration on combined and cogeneration cycles. The goal of this tutorial is to provide a nonmathematical treatment of performance deterioration to help plant operators grasp the underlying causes, effects, and measurement of gas turbine performance degradation. Topics covered will include fouling, effect of blade surface roughness, erosion, corrosion, losses of ancillary systems (inlet/ outlet), clearances effects, and the impact of fuels on GT combustion and degradation. To understand the impact of degradation, basic concepts of gas turbine matching and off design operation will be addressed first. The three major sources of performance deterioration will be discussed: Recoverable Deterioration- can be removed by actions during operation of the gas turbine; Unrecoverable Deterioration- can be recovered by an overhaul but not during operation; Permanent Deterioration- residual deterioration present even after a major overhaul. Control aspects and their interaction with performance deterioration mechanisms will also be covered. Lastly, condition monitoring approaches focused on the detection of deterioration will be reviewed

Aerothermal-Mechanical Health Monitoring And Diagnostics Or Turbo-Compressor Sets

PaperPg. 75-94.High speed turbomachinery plays a critical role in today's petrochemical industry. There are very high penalty costs associated with nonavailability and catastrophic failure of critical unspared trains. Additionally the fuel and maintenance costs over the life cycle of plant turbomachinery is very significant. Both of the above factors point to the need for health monitoring and diagnostic systems. The petrochemical industry has in the past placed a heavy emphasis on mechanical (vibration) analysis for both health monitoring and diagnostics. This paper presents a methodology in which both mechanical and aerothermal parameters are utilized for machinery health monitoring, prognosis and diagnosis