Latest Developments in Optimizing Reformer Tube Life Through Advanced Inspection and Remaining Life Assessment

2013 ◽  
Author(s):  
Brian Shannon ◽  
Carl E. Jaske
Keyword(s):  
Operating Conditions ◽  
Life Assessment ◽  
Inspection System ◽  
Remaining Life ◽  
Centrifugally Cast ◽  
Steam Methane ◽  
Recent Developments ◽  
Reformer Tubes ◽  
Remaining Life Assessment ◽  
Tube Life

Steam methane reformer tubes must withstand high temperature and pressures during operation and are made from centrifugally cast austenitic materials, typically HK-40, HP Modified, and Micro-Alloy materials. Since operating conditions can result in various forms of damage, the identification and quantification of damage is of vital importance if tube life is to be predicted accurately. This paper describes the recent developments in an integrated inspection system which uses multiple NDT techniques to provide a most comprehensive assessment of current tube condition. This system is coupled with a sophisticated remaining life assessment software model which predicts the remaining life of each tube in a furnace.

Power Turbine Remaining Life Assessment

2001 ◽  
Author(s):  
Bruce deBeer ◽  
Paul Chilcott ◽  
Dave Seib
Keyword(s):  
Analytical Techniques ◽  
Spare Parts ◽  
Operating Conditions ◽  
Life Assessment ◽  
Remaining Life ◽  
Operating Cycle ◽  
Statistical Probability ◽  
Power Turbine ◽  
Remaining Life Assessment ◽  
As Stress

The design life of an industrial power turbine has traditionally been 100,000 hours or 5,000 starts, based on a specific set of assumed operating conditions. Actual operating conditions vary from site to site, and are often less severe than the initial assumptions used by the manufacturer. This is why Dresser-Rand has developed a Remaining Life Assessment program. The objective of this program is to assist operators in extending the life of expensive components, determining inspection intervals, developing component replacement schedules, and establishing a spare parts stocking program. A comprehensive remaining life assessment must take into account unit operating history, a thorough non destructive examination of the components being considered for reuse, thermal and structural analyses using current analytical techniques, and material evaluations. There is some amount of variability in the input and output for each of these steps. Defects smaller than a given size are not always detected, material test results have a statistical distribution, and each operating cycle is unique. Traditionally the expected life has been based on a predetermined set of assumptions, such as stress analyses using typical dimensions, minus three sigma fatigue and creep properties, etc. The Dresser-Rand approach accounts for these inherent variations and establishes the statistical probability of successfully extending power turbine life without failure or unplanned maintenance as a function of time.

Introduction and Overview

1989 ◽  
pp. 1-20
Keyword(s):  
Power Plants ◽  
Failure Modes ◽  
Failure Criteria ◽  
Operating Conditions ◽  
Life Assessment ◽  
Remaining Life ◽  
Long Term Effects ◽  
Remaining Service Life ◽  
Design Life ◽  
Remaining Life Assessment

Abstract The ability to accurately assess the remaining life of components is essential to the operation of plants and equipment, particularly those in service beyond their design life. This, in turn, requires a knowledge of material failure modes and a proficiency for predicting the near and long term effects of mechanical, chemical, and thermal stressors. This chapter presents a broad overview of the types of damage to which materials are exposed at high temperatures and the approaches used to estimate remaining service life. It explains how operating conditions in power plants and oil refineries can cause material-related problems such as embrittlement, creep, thermal fatigue, hot corrosion, and oxidation. It also discusses the factors and considerations involved in determining design life, defining failure criteria, and implementing remaining-life-assessment procedures.

Mechanical strength and microstructural observations for remaining life assessment of service exposed 24Ni–24Cr–1.5Nb cast austenitic steel reformer tubes

2008 ◽  
Vol 15 (6) ◽  
pp. 723-735 ◽  
Author(s):  
Jaganathan Swaminathan ◽  
Prabha Prasad ◽  
Manoj Kumar Gunjan ◽  
Krishna Gugloth ◽  
Prabir Kumar Roy ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Austenitic Steel ◽  
Life Assessment ◽  
Remaining Life ◽  
Reformer Tubes ◽  
Remaining Life Assessment

Fitness for Service and Remaining Life Assessment for 1-1/4Cr-1/2Mo Reactor System Piping on a Catalytic Reformer Unit

2006 ◽  
Author(s):  
Ayman M. Cheta ◽  
Ray Konet ◽  
F. Skip Hoyt
Keyword(s):  
Creep Damage ◽  
Pressure Vessels ◽  
Operating Conditions ◽  
Life Assessment ◽  
Low Alloy Steels ◽  
General Corrosion ◽  
Remaining Life ◽  
Reheat Cracking ◽  
Remaining Life Assessment ◽  
Welded Pipe

Fitness for service and remaining life assessment were performed on high temperature reactor piping to verify mechanical integrity for a desired remaining life. The NPS 20 1-1/4Cr-1/2Mo piping, which is the subject of this paper, was built in 1968 to the 1966 edition of ASA B31.3 for design conditions 465 psi at 950 °F / 365 psi at 1000 °F (3.16 MPa at 510 °C / 2.48 MPa at 538 °C) for hydrogen and naphtha service. The actual operating conditions are 400 psi at 900 °F / 330 psi at 950 °F (2.72 MPa at 482 °C / 2.24 MPa at 510 °C). Due to numerous reported failures in the industry in the 1980’s, the ASME codes for piping and pressure vessels lowered the allowable stresses for low alloy steels operating in the creep range, mainly above 900 °F (482 °C). Piping systems designed prior to changing the allowable stress do not satisfy today’s codes. The operating stresses which can lead to failure from potential damage mechanisms, e.g. creep, reheat cracking and general corrosion, are defined and their impact on fitness-for-service and remaining life evaluated. Acceptance criteria for different types of defects were established prior to the unit maintenance turnaround by: 1. Finite element modeling of assumed different degrees of weld peaking and pipe out-of-roundness for longitudinally welded pipe. 2. Piping flexibility / stress analysis to identify areas with the highest operating stresses. 3. Stresses from 1 and 2 above were used to calculate the creep life based on Larson-Miller parameter (API 530). Acceptable flaw sizes were limited by the desired remaining life. Inspection plans were developed to inspect for reheat cracking, creep damage, peaking, out of roundness, as well as general corrosion.

Structural Response and Remaining Life of Damaged Composites

2015 ◽  
Vol 813-814 ◽  
pp. 106-110
Author(s):  
Dalbir Singh ◽  
C. Ganesan ◽  
A. Rajaraman
Keyword(s):  
Hybrid Approach ◽  
Experimental Studies ◽  
Structural Response ◽  
Material Behavior ◽  
Experimental Results ◽  
Life Assessment ◽  
Nonlinear Material ◽  
Remaining Life ◽  
Design Effectiveness ◽  
Remaining Life Assessment

Composites are being used in variety of applications ranging from defense and aircraft structures, where usage is profuse, to vehicle structures and even for repair and rehabilitation. Most of these composites are made of different laminates glued together with matrix for binding and now-a-days fibers of different types are embedded in a composite matrix. The characterizations of material properties of composites are mostly experimental with analytical modeling used to simulate the system behavior. But many times, the composites develop damage or distress in the form of cracking while they are in service and this adds a different dimension as one has to evaluate the response with the damage so that its performance during its remaining life is satisfactory. This is the objective of the present study where a hybrid approach using experimental results on damaged specimens and then analytical finite element are used to evaluate response. This will considerably help in remaining life assessment-RLA- for composites with damage so that design effectiveness with damage could be assessed. This investigation has been carried out on a typical composite with carbon fiber reinforcements, manufactured by IPCL Baroda (India) with trade name INDCARF-30. Experimental studies were conducted on undamaged and damaged specimens to simulate normal continuous loading and discontinuous loading-and-unloading states in actual systems. Based on the experimental results, material characterization inputs are taken and analytical studies were carried out using ANSYS to assess the response under linear and nonlinear material behavior to find the stiffness decay. Using stiffness decay RLA was computed and curves are given to bring the influence of type of damage and load at which damage had occurred.

scholarly journals The thermal history and stress state of a fresh steam-pipeline influencing its remaining service life

2011 ◽  
Vol 15 (3) ◽  
pp. 691-704 ◽  
Author(s):  
Gordana Bakic ◽  
Vera Sijacki-Zeravcic ◽  
Milos Djukic ◽  
Stevan Maksimovic ◽  
Dusan Plesinac ◽  
...  
Keyword(s):  
Service Life ◽  
Elevated Temperatures ◽  
Operating Temperature ◽  
Life Assessment ◽  
Temperature History ◽  
Significant Variable ◽  
Remaining Life ◽  
Pipe Bend ◽  
Steam Pipeline ◽  
Remaining Life Assessment

The service life of thick-walled power plant components exposed to creep, as is the case with pipelines of fresh- and re-heated steam, depend on the exhaustion rate of the material. Plant operation at elevated temperatures and at temperatures below designed temperatures all relates to the material exhaustion rate, thus complicating remaining life assessment, whereas the operating temperature variation is a most common cause in the mismatching of real service- and design life. Apart from temperature, the tube wall stress is a significant variable for remaining life assessment, whose calculation depends on the selected procedure, due to the complex pipeline configuration. In this paper, a remaining life assessment is performed according to the Larson-Miller parametric relation for a ?324?36 pipe bend element of a fresh steam-pipeline, made of steel class 1Cr0.3Mo0.25V, after 160 000 hours of operation. The temperature history of the pipeline, altogether with the pipe bend, is determined based on continuous temperature monitoring records. Compared results of remaining life assessment are displayed for monitored temperature records and for designed operating temperature in the same time period. The stress calculation in the pipe bend wall is performed by three methods that are usually applied so to emphasize the differences in the obtained results of remaining life assessment.

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