Remaining Life Assessment Technology Applied to Steam Turbines and Hot Gas Expanders

2011 ◽  
Author(s):  
Phillip Dowson ◽  
David Dowson
Keyword(s):  
Fatigue Life ◽  
Oil Refinery ◽  
Life Assessment ◽  
Life Extension ◽  
Remaining Life ◽  
Steam Turbines ◽  
Hot Gas ◽  
Creep Fatigue ◽  
Assessment Technology ◽  
Remaining Life Assessment

In today’s market place, a large percentage of oil refinery, petrochemical, and power generation plants throughout the world have been trying to reduce their operation cost by extending the service life of their critical machines, such as steam turbines, beyond the design life criteria. The key ingredient in plant life extension is Remaining Life Assessment Technology. This paper will outline the Remaining Life Assessment procedures, and review the various damage mechanisms such as creep, fatigue, creep-fatigue and various embrittlement mechanisms that can occur in these machines. Also highlighted will be the various testing methods for determining remaining life or life extension of components such as high precision STR (Stress Relaxation Test), which determines creep strength, and CDR (Constant Displacement Rate) Test, which evaluates fracture resistance. Other tests such as replication/microstructure analysis and toughness tests will also be reviewed for calculating the remaining life or life extension of the components. Use of the latest computer software will also be highlighted showing how creep-life, fatigue-life and creep/fatigue-life calculations can be performed. Also shown will be an actual life extension example of a hot gas expander performed in the field.

scholarly journals Recent Life Assessment Technology for Existing Steam Turbines

2005 ◽  
Author(s):  
K. Saito ◽  
A. Sakuma ◽  
M. Fukuda
Keyword(s):  
High Temperature ◽  
Power Plants ◽  
High Reliability ◽  
Thermal Power ◽  
Life Assessment ◽  
Life Extension ◽  
Steam Turbines ◽  
Term Operation ◽  
Assessment Technology ◽  
Technical Features

A large and growing portion of electricity is produced by aging thermal power plants. Although excellent, high quality materials such as CrMoV steel and 12% Cr steel, etc. are used for the steam turbines, various forms of metallurgical degradation, due to creep and fatigue, etc. affect the parts and components during long-term operation at high temperature. Extending the life of steam turbines and ensuring high reliability requires life assessment technology, scheduled repairing, conversion, modification and upgrading of components in order to provide a stable power supply. As the high temperature parts and components of aged steam turbines are mainly metallurgically damaged by creep, fatigue and the interaction of both, life assessment combined with analytical and nondestructive methods is essential for realizing strategic plant life extension. We have developed a life assessment technology that takes material degradation into consideration, and have applied the procedure to more than 650 units and 2500 components since 1983. A rotor bore replication device was developed in 1989 for the purpose of nondestructive observation of creep voids and supporting the validity of life prediction results. This paper describes the technical features and applied experience of recent life assessment technology for existing high temperature steam turbines.

Life Assessment of Steam-Turbine Components

1989 ◽  
pp. 265-328
Keyword(s):  
High Temperature ◽  
Steam Turbine ◽  
Failure Modes ◽  
Assessment Methods ◽  
Life Assessment ◽  
Remaining Life ◽  
Steam Turbines ◽  
Damage Mechanisms ◽  
Design Considerations ◽  
Remaining Life Assessment

Abstract This chapter covers the failure modes and mechanisms of concern in steam turbines and the methods used to assess remaining component life. It provides a detailed overview of the design considerations, material requirements, damage mechanisms, and remaining-life-assessment methods for the most-failure prone components beginning with rotors and continuing on to casings, blades, nozzles, and high-temperature bolts. The chapter makes extensive use of images, diagrams, data plots, and tables and includes step-by-step instructions where relevant.

The Assessment of Remaining Life of Chemical Reactor Exposed to Creep and Fatigue

2008 ◽  
Vol 399 ◽  
pp. 51-59
Author(s):  
Horia Mateiu ◽  
Traian Fleşer ◽  
Alin Constantin Murariu
Keyword(s):  
Thermal Fatigue ◽  
Fatigue Testing ◽  
Welding Process ◽  
Chemical Reactor ◽  
Life Assessment ◽  
Petrochemical Plant ◽  
Remaining Life ◽  
Creep Fatigue ◽  
Asme Code ◽  
Remaining Life Assessment

The paper presents an application according the reliability and remining life assessment of the reactor (coxing box) from a petrochemical plant, after failure in welding joint of plated shell from W1.5423 (16Mo5) steel with 25 mm thickness, plated with W1.4002 stainless steel with 3 mm thickness. The reactor failure it has associated with initial flaws from welding process, which have accelerated remaining life exhaustion. The assessment made in two steps. It has used VII section of ASME code specifications and iRiS-Thermo expert system for preliminary remaining life assessment. Concomitantly, it was performed the experimental creep and thermal fatigue testing. The program results have defined creep and thermal fatigue exhaustion and its remaining life at common creep-fatigue action, in condition of safety exploitation. It was emphasized the possibility of use an extra 40,000 hours of rehabilitated reactor in the safety condition of normal parameters.

Corrosion and Remaining Life Assessment

2021 ◽  
pp. 1-7
Author(s):  
Carlos R. Corleto ◽  
Michael Hoerner
Keyword(s):  
Oil Refinery ◽  
Life Assessment ◽  
Localized Corrosion ◽  
Remaining Life ◽  
Minimum Thickness ◽  
Failure Assessment ◽  
Level 3 ◽  
Remaining Life Assessment ◽  
Corrosion Under Insulation ◽  
Level 2

Abstract This article illustrates the use of the fitness-for-service (FFS) code to assess the serviceability and remaining life of a corroded flare knockout drum from an oil refinery, two fractionator columns affected by corrosion under insulation in an organic sulfur environment, and an equalization tank with localized corrosion in the shell courses in a chemicals facility. In the first two cases, remaining life is assessed by determining the minimum thickness required to operate the corroded equipment. The first is based on a Level 2 FFS assessment, while the second involves a Level 3 assessment. The last case involves several FFS assessments to evaluate localized corrosion in which remaining life was assessed by determining the minimum required thickness using the concept of remaining strength factor for groove-like damage and evaluating crack-like flaws using the failure assessment diagram. Need for caution in predicting remaining life due to corrosion is also covered.

Remaining Life Assessment and Life Extension of Offshore Pipelines

2018 ◽  
Author(s):  
Jens P. Tronskar
Keyword(s):  
Life Assessment ◽  
Life Extension ◽  
Remaining Life ◽  
Original Design ◽  
Offshore Pipelines ◽  
Field Development ◽  
Design Life ◽  
The Future ◽  
Cost Efficient ◽  
Remaining Life Assessment

Cost efficient offshore field development often involves tiebacks to existing field infrastructure. Efficient field development requires life extension of existing production facilities and pipelines to accommodate the new field resources over their life expectation. For fields near the tail end of their production the pipelines may be close to the end of their design life, and it must be shown that they have potential for extended life beyond the original design life until the end of the period of operation of the new field. Offshore pipelines are designed and constructed to recognized standards, such as the widely applied DNV OS-F101 2013 Submarine Pipelines Systems and earlier versions. The latest edition of the code was recently issued as a standard with some major updates and a modified code number i.e. DNVGL ST-F101 [1]. As pipelines age, they will inevitably be exposed to various types of degradation and an Operator must be able to both assess the significance of this damage and the pipeline remaining life to ensure that the pipelines do not fail as they age before the end of their design lives. Currently, many pipelines are operated far beyond the original design life and as mentioned above for cost efficient field development the pipeline operator often needs to demonstrate that the pipeline’s useful life can be extended another 10 or in some cases up to 30 years. For some pipelines, new operating conditions will be introduced by tie-in of new fields and this will impact the future rate of degradation. Hence, it cannot be assumed that the future degradation will be similar or less severe than experienced since commissioning of the pipeline. Extension of the life of the pipeline can be demonstrated by adopting methods of analysis that show the line is safe for an extended life under the future expected operating condition. This paper describes the risk based approach applied for pipeline remaining life and life extension analyses based on DNV GL codes and other relevant recommended practices. For illustration of the methodology a typical case of remaining life assessment of and life extension of a gas export pipeline is presented in the Case Study.

Remaining life assessment technology of machine equipment

2016 ◽  
Vol 2016 (0) ◽  
pp. 531
Author(s):  
Yoshiaki NISHINA ◽  
Daisuke IMANISHI ◽  
Yasuyuki KURIHARA
Keyword(s):  
Life Assessment ◽  
Remaining Life ◽  
Assessment Technology ◽  
Remaining Life Assessment
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