Online Creep-Fatigue Monitoring of Cyclic Operation in a Coal-Fired Power Plant

2017 ◽  
Author(s):  
Stan T. Rosinski ◽  
Kent Coleman ◽  
Mario Berasi ◽  
Curt Carney ◽  
Ulrich Woerz ◽  
...  
Keyword(s):  
High Temperature ◽  
Power Plant ◽  
Fatigue Damage ◽  
Power Plants ◽  
Transfer Functions ◽  
Stress Transfer ◽  
Operating Conditions ◽  
Element Analysis ◽  
Thermal Transients ◽  
Plant Components

Coal-fired power plants are often required to cycle extensively and operate relatively infrequently due to power market conditions and an increasingly broad deployment of renewable energy. This cyclic (start-stop and/or fast ramp rate) operation can result in accumulation of fatigue damage, particularly in thick-walled components such as high temperature headers that experience the greatest thermal transients. In addition, components exposed to high temperature and pressure experience creep damage over time. Tracking the accumulation of creep and fatigue damage can aid in life management of these components. EPRI developed the Creep-FatiguePro™ system to monitor the accumulation of creep and fatigue damage in plant components while considering component geometry and the ongoing changes in operating conditions (temperatures, pressures and flow rates). The software requires a configuration process to define stress transfer functions for damage analysis and often involves performing a finite element analysis for each component geometry. Although accurate, this process can be time-consuming, especially if a large number of components are to be monitored. In a recent application of this system at the As Pontes power plant in Spain, a simple closed form analytical solution was used in the configuration process in order to more rapidly obtain the stress transfer functions. For direct interaction with the plant’s data historian, the software was also modified to support connection to the plant data system. Results using the two configuration approaches will be compared and recommendations made for future use in monitoring creep and fatigue damage in power plant components.

Failure Analysis of Spiral Water Wall Tube Cracking in Ultra-Supercritical Power Plant Boiler

2016 ◽  
Author(s):  
Jun Si ◽  
Zhenrong Yan ◽  
Jianjun Chen
Keyword(s):  
Residual Stress ◽  
High Temperature ◽  
Power Plant ◽  
Failure Analysis ◽  
Power Plants ◽  
Composition Analysis ◽  
Element Analysis ◽  
Water Wall ◽  
Water Wall Tube ◽  
Weld Heat

The efficiency of conventional boiler/steam turbine fossil power plants has strong relationship to the steam temperature and pressure. At present, steam temperatures of the most efficient fossil power plants are now in the 600°C range. Higher-strength materials are needed for upper water wall tube of boilers with steam pressure above 24 MPa. A high-strength 2.5%Cr steel recently approved by ASME code as T23 is the preferred candidate material for this application. Due to its superior properties, T23 steel is typically not post-weld heat treated. However, after several years running there are a lot of incident reports for T23 tubes especially the breakage of weldment in the ultra-supercritical power plant. This is cause for concern for T23 tubes weldment used under high temperature environments. Previous studies showed that the residual stress may play an important role to the performance of spiral water wall tube. In this paper, the distribution of residual stress in T23 tube weldment has been investigated in detail. Inner wall cracks were found at the butt-jointed seam region of spiral water wall tubes by radiographic testing after one year’s operation. Failure analysis of the spiral water wall tube cracking was conducted by chemical composition analysis, mechanical testing and finite element analysis in this paper. It was found that localized residual stress after the weld process caused concentrated stress, which is the primary reason for failure. Our studies illustrate the necessity of post weld heat treatment for the T23 tubes used under high temperature.

Human reliability in non-destructive inspections of nuclear power plant components: modeling and analysis

2019 ◽  
Vol 7 (2B) ◽  
Author(s):  
Vanderley Vasconcelos ◽  
Wellington Antonio Soares ◽  
Raissa Oliveira Marques ◽  
Silvério Ferreira Silva Jr ◽  
Amanda Laureano Raso
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Human Factors ◽  
Nuclear Power ◽  
Power Plants ◽  
Failure Modes ◽  
Cooling System ◽  
Human Reliability ◽  
Non Destructive ◽  
Plant Components

Non-destructive inspection (NDI) is one of the key elements in ensuring quality of engineering systems and their safe use. This inspection is a very complex task, during which the inspectors have to rely on their sensory, perceptual, cognitive, and motor skills. It requires high vigilance once it is often carried out on large components, over a long period of time, and in hostile environments and restriction of workplace. A successful NDI requires careful planning, choice of appropriate NDI methods and inspection procedures, as well as qualified and trained inspection personnel. A failure of NDI to detect critical defects in safety-related components of nuclear power plants, for instance, may lead to catastrophic consequences for workers, public and environment. Therefore, ensuring that NDI is reliable and capable of detecting all critical defects is of utmost importance. Despite increased use of automation in NDI, human inspectors, and thus human factors, still play an important role in NDI reliability. Human reliability is the probability of humans conducting specific tasks with satisfactory performance. Many techniques are suitable for modeling and analyzing human reliability in NDI of nuclear power plant components, such as FMEA (Failure Modes and Effects Analysis) and THERP (Technique for Human Error Rate Prediction). An example by using qualitative and quantitative assessesments with these two techniques to improve typical NDI of pipe segments of a core cooling system of a nuclear power plant, through acting on human factors issues, is presented.

Real-Time Thermodynamic Performance Monitoring and Optimum Thermoeconomic Operation of Power Plants

2011 ◽  
Author(s):  
G. Hariharan ◽  
B. Kosanovic
Keyword(s):  
Linear Programming ◽  
Power Plant ◽  
Real Time ◽  
Power Plants ◽  
Operating Conditions ◽  
Recursive Least Squares ◽  
Time Data ◽  
Real Time Data ◽  
One Step ◽  
Inputs And Outputs

The ability of modern power plant data acquisition systems to provide a continuous real-time data feed can be exploited to carry out interesting research studies. In the first part of this study, real-time data from a power plant is used to carry out a comprehensive heat balance calculation. The calculation involves application of the first law of thermodynamics to each powerhouse component. Stoichiometric combustion principles are applied to calculate emissions from fossil fuel consuming components. Exergy analysis is carried out for all components by the combined application of the first and second laws of thermodynamics. In the second part of this study, techniques from the field of System Identification and Linear Programming are brought together in finding thermoeconomically optimum plant operating conditions one step ahead in time. This is done by first using autoregressive models to make short-term predictions of plant inputs and outputs. Then, parameter estimation using recursive least squares is used to determine the relations between the predicted inputs and outputs. The estimated parameters are used in setting up a linear programming problem which is solved using the simplex method. The end result is knowledge of thermoeconomically optimum plant inputs and outputs one step ahead in time.

Assessment of Fatigue Life for High-Temperature Pipeline Welds Using X-Ray Diffraction Technique

2007 ◽  
Vol 353-358 ◽  
pp. 130-133
Author(s):  
Keun Bong Yoo ◽  
Jae Hoon Kim
Keyword(s):  
High Temperature ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Power Plants ◽  
Low Cycle Fatigue ◽  
Diffraction Method ◽  
Life Assessment ◽  
Fatigue Properties ◽  
X Ray Diffraction ◽  
X Ray

The objective of this study is to examine the feasibility of the X-ray diffraction method for the fatigue life assessment of high-temperature steel pipes used for main steam pipelines, re-heater pipelines and headers etc. in power plants. In this study, X-ray diffraction tests were performed on the specimens simulated for low cycle fatigue damage, in order to estimate fatigue properties at the various stages of fatigue life. As a result of X-ray diffraction tests, it was confirmed that the full width at the half maximum (FWHM) decreased with an increase in the fatigue life ratio, and that the FWHM and the residual stress due to fatigue damage were algebraically linearly related to the fatigue life ratio. From this relationship, a direct assessment of the remaining fatigue life was feasible.

An Evaluation of Creep-Fatigue Damage for the Prototype Process Heat Exchanger of the NHDD Plant

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Hyeong-Yeon Lee ◽  
Kee-Nam Song ◽  
Yong-Wan Kim ◽  
Sung-Deok Hong ◽  
Hong-Yune Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Temperature ◽  
Fatigue Damage ◽  
Inlet Temperature ◽  
Alloy 617 ◽  
Element Analysis ◽  
Creep Fatigue ◽  
Process Heat ◽  
Very High

A process heat exchanger (PHE) transfers the heat generated from a nuclear reactor to a sulfur-iodine hydrogen production system in the Nuclear Hydrogen Development and Demonstration, and was subjected to very high temperature up to 950°C. An evaluation of creep-fatigue damage, for a prototype PHE, has been carried out from finite element analysis with the full three dimensional model of the PHE. The inlet temperature in the primary side of the PHE was 950°C with an internal pressure of 7 MPa, while the inlet temperature in the secondary side of the PHE is 500°C with internal pressure of 4 MPa. The candidate materials of the PHE were Alloy 617 and Hastelloy X. In this study, only the Alloy 617 was considered because the high temperature design code is available only for Alloy 617. Using the full 3D finite element analysis on the PHE model, creep-fatigue damage evaluation at very high temperature was carried out, according to the ASME Draft Code Case for Alloy 617, and technical issues in the Draft Code Case were raised.

Seven Years of Putnam Plant Operation: Part 1–2

1984 ◽  
Author(s):  
V. C. Tandon ◽  
D. A. Moss
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Heat Rate ◽  
Combined Cycle ◽  
High Availability ◽  
Fuel Utilization ◽  
Residual Oil ◽  
L System ◽  
Efficient Power ◽  
Plant Components

Florida Power and Light Company’s Putnam Station, one of the most efficient power plants in the FP&L system, is in a unique and enviable position from an operational viewpoint. Its operation, in the last seven years, has evolved through a triple phase fuel utilization from distillate to residual oil and finally to natural gas. This paper compares the availability/reliability of the Putnam combined cycle station and the starting reliability of the combustion turbines in each of the operating periods. A review of the data shows that high availability/reliability is not fuel selective when appropriate actions are developed and implemented to counteract the detractors. This paper also includes experience with heat rate and power degradation of various power plant components and programs implemented to restore performance.

Turbo Gas Power Plants Performance Evaluation for Putting Into Commercial Operation

2009 ◽  
Author(s):  
Erik Rosado Tamariz ◽  
Norberto Pe´rez Rodri´guez ◽  
Rafael Garci´a Illescas
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Performance Test ◽  
Operating Conditions ◽  
Technical Requirements ◽  
Requirements Specifications ◽  
Commercial Operation ◽  
International Regulations ◽  
Operational Tests

In order to evaluate the performance of new turbo gas power plants for putting in commercial operation, it was necessary to supervise, test and, if so the case, to approve the works of commissioning, operational and acceptance of all equipments and systems that constitute the power plant. All this was done with the aim of guaranteeing the satisfactory operation of these elements to accomplish the function for which they were developed. These activities were conducted at the request of the customer to confirm and observe that the evidence of the tests was carried out according to the specifications and international regulations. The putting into commercial operation activities were done in collaboration with the supplier and manufacturer of equipment, the client and the institution responsible for certification and approval of the plant. All this in a logical and chronological order for the sequence of commissioning tests, operation and acceptance. Commissioning tests were carried out on-site at normal operating conditions, according to the design and operation needs of each power plant of a group of 14. Once the commissioning tests were completely executed and in a satisfactory manner, operational tests of the plants were developed. This was done by considering that they must operate reliable, stable, safe and automatically, satisfying at least, one hundred hours of continuous operation at full load. After evaluating the operational capacity of the machine, it was necessary to determinate the quality of the plant by carrying out a performance test. Finally, it was verified if every unit fulfills the technical requirements established in terms of heat capacity of the machine, noise levels and emissions. As a result of this process, it is guaranteed to the customer that the turbo gas power plants, their systems and equipments, satisfy the requirements, specifications and conditions in agreement with the supplier and manufacturers referring to the putting into commercial operation of the plant.

Power Augmentation Technologies for Gas Turbines: Alternatives for an Existing Simple Cycle Power Plant in Peru

2019 ◽  
Author(s):  
Cesar Celis ◽  
Sergio Peralta ◽  
Walter Galarza
Keyword(s):  
Power Plant ◽  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
Operating Conditions ◽  
Simple Cycle ◽  
Specific Power ◽  
Environmental Implications ◽  
Augmentation Techniques ◽  
Type Power

Abstract The influence of different power augmentation techniques used in gas turbines on the performance of simple cycle type power plants is assessed in this work. A computational model and tool realistically describing the performance of a typical simple cycle type power plant at design and off-design point conditions is initially developed. This tool is complemented with different models of power augmentation technologies. Finally, the whole model including both power plant and power augmentation techniques is used to analyze a case study involving a particular power plant in Peru. The results from the simulations of the specific power plant indicate that power output can be increased through all the evaluated power augmentation technologies. These results show indeed that technologies based on absorption refrigeration systems produce the largest gains in terms of power output (7.1%) and thermal efficiency (0.7%). Such results confirm the suitability of these systems for simple cycle type power plant configurations operating under hot and humid operating conditions as those accounted for here. From an economic perspective, considering the net present value as the key parameter defining the feasibility of a project in this category, power augmentation techniques based on absorption cooling systems result also the most suitable ones for the studied power plant. Power augmentation techniques environmental implications are also quantified in terms of CO2 emissions.

Influence of a Variable in Time Heat Transfer Coefficient on Stresses in Model of Power Plant Components

2013 ◽  
Author(s):  
Jerzy Okrajni ◽  
Mariusz Twardawa
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Mechanical Behaviour ◽  
Power Plants ◽  
Thermal Loading ◽  
Computer Modelling ◽  
Temperature Fields ◽  
Fluid Medium ◽  
Stress Changes ◽  
Plant Components

The paper discusses the issue of modelling of strains and stresses resulting from heating and cooling processes of components in power plants. The main purpose of the work is to determine the mechanical behaviour of power plant components operating under mechanical and thermal loading. Finite element method (FEM) has been used to evaluate the temperature and stresses changes in components as a function of time. Temperature fields in the components of power plants are dependent, among parameters, on variable heat-transfer conditions between components and the fluid medium, which may change its condition, flowing inside them. For this reason, evaluation of the temperature field and the consequent stress fields requires the use of heat-transfer coefficients as time-dependent variables and techniques for determining appropriate values for these coefficients should be used. The methodology of combining computer modelling of the temperature fields with its measurements performed at selected points of the pipelines may be used in this case. The graphs of stress changes as a function of time have been determined for the chosen plant components. The influence of the heat transfer conditions on the temperature fields and mechanical behaviour of components have been discussed.

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