The Study of Inspection and Supervision for Overage Service Pressure Vessels in Petrochemical Plants

2019 ◽  
Vol 795 ◽  
pp. 346-351
Author(s):  
Jun Si ◽  
Jin Sha Xu ◽  
Yu Qing Yang ◽  
Xiang Wen ◽  
Xiao Ying Tang
Keyword(s):  
Service Life ◽  
Risk Evaluation ◽  
Damage Mechanism ◽  
Evaluation Methods ◽  
Pressure Vessels ◽  
Basic Theory ◽  
Basic Principles ◽  
Integrity Assessment ◽  
Potential Damage ◽  
Risk Supervision

Overage service pressure vessels are widespread in China. These pressure vessels may be suffered from some forms of material deterioration and damage with an increasing possibility of failure. However, some of the potential damage mechanism couldn’t be found if the inspection strategies were carried out in according with traditional inspection regulations. Through identifying the damage mechanism of these pressure vessels, the risk evaluation would be carried out by use of RBI technology in company with the structure integrity assessment. The procedure of inspection for overage service pressure vessels was developed, and some of the reasonable inspection and testing requirements and basic principles also were proposed. The three levels evaluation methods of residual safe-service life for these pressure vessels were proposed. At the same time, the risk supervision method of these pressure vessels was established by use on the risk basic theory.

Effect of Carbide Content on Temper Embrittlement of 2.25Cr1Mo Steel

2016 ◽  
Author(s):  
Yian Wang ◽  
Guoshan Xie ◽  
Zheng Zhang ◽  
Xiaolong Qian ◽  
Yufeng Zhou ◽  
...  
Keyword(s):  
High Temperature ◽  
Pressure Vessel ◽  
High Stress ◽  
Temper Embrittlement ◽  
Damage Mechanism ◽  
Pressure Vessels ◽  
Nondestructive Method ◽  
Operating Conditions ◽  
Low Alloy Steels ◽  
Carbide Content

Temper embrittlement is a common damage mechanism of pressure vessels in the chemical and petrochemical industry serviced in high temperature, which results in the reduction of roughness due to metallurgical change in some low alloy steels. Pressure vessels that are temper embrittled may be susceptible to brittle fracture under certain operating conditions which cause high stress by thermal gradients, e.g., during start-up and shutdown. 2.25Cr1-Mo steel is widely used to make hydrogenation reactor due to its superior combination of high mechanical strength, good weldability, excellent high temperature hydrogen attack (HTHA) and oxidation-resistance. However, 2.25Cr-1Mo steel is particularly susceptible to temper embrittlement. In this paper, the effect of carbide on temper embrittlement of 2.25Cr-1Mo steel was investigated. Mechanical properties and the ductile-brittle transition temperature (DBTT) of 2.25Cr-1Mo steel were measured by tensile test and impact test. The tests were performed at two positions (base metal and weld metal) and three states (original, step cooling treated and in-service for a hundred thousand hours). The content and distribution of carbides were analyzed by scanning electron microscope (SEM). The content of Cr and Mo elements in carbide was measured by energy dispersive X-ray analysis (EDS). The results showed that the embrittlement could increase the strength and reduce the plasticity. Higher carbide contents appear to be responsible for the higher DBTT. The in-service 2.25Cr-1Mo steel showed the highest DBTT and carbide content, followed by step cooling treated 2.25Cr-1Mo steel, while the as-received 2.25Cr-1Mo steel has the minimum DBTT and carbide content. At the same time, the Cr and Mo contents in carbide increased with the increasing of DBTT. It is well known that the specimen analyzed by SEM is very small in size, sampling SEM specimen is convenient and nondestructive to pressure vessel. Therefore, the relationship between DBTT and the content of carbide offers a feasible nondestructive method for quantitative measuring the temper embrittlement of 2.25Cr-1Mo steel pressure vessel.

French RPV PTS Assessment: An Overview of EDF Research and Development in Progress on Thermalhydraulic, Materials and Mechanical Aspects

2003 ◽  
Author(s):  
Dominique Moinereau ◽  
Jean-Michel Frund ◽  
Henriette Churier-Bossennec ◽  
Georges Bezdikian ◽  
Alain Martin
Keyword(s):  
Structural Integrity ◽  
Three Dimensional ◽  
Crack Arrest ◽  
Pressure Vessels ◽  
Short Description ◽  
Constraint Effect ◽  
Materials Properties ◽  
Integrity Assessment ◽  
Pressurized Thermal Shock ◽  
Reactor Pressure

A significant extensive Research & Development work is conducted by Electricite´ de France (EDF) related to the structural integrity re-assessment of the French 900 and 1300 MWe reactor pressure vessels in order to increase their lifetime. Within the framework of this programme, numerous developments have been implemented or are in progress related to the methodology to assess flaws during a pressurized thermal shock (PTS) event. The paper contains three aspects: a short description of the specific French approach for RPV PTS assessment, a presentation of recent improvements on thermalhydraulic, materials and mechanical aspects, and finally an overview of the present R&D programme on thermalhydraulic, materials and mechanical aspects. Regarding the last aspect on present R&D programme, several projects in progress will be shortly described. This overview includes the redefinition of some significant thermalhydraulic transients based on some new three-dimensional CFD computations (focused at the present time on small break LOCA transient), the assessment of vessel materials properties, and the improvement of the RPV PTS structural integrity assessment including several themes such as warm pre-stress (WPS), crack arrest, constraint effect ....

Overview of Benefit–Risk Evaluation Methods: A Spectrum from Qualitative to Quantitative

2017 ◽  
pp. 145-174
Author(s):  
George Quartey ◽  
Chunlei Ke ◽  
Christy Chuang-Stein ◽  
Weili He ◽  
Qi Jiang ◽  
...  
Keyword(s):  
Risk Evaluation ◽  
Evaluation Methods

A Rational Methodology for Determination of Service Life for a Delayed Coker Drum

2015 ◽  
Author(s):  
John J. Aumuller ◽  
Jie Chen ◽  
Vincent A. Carucci
Keyword(s):  
Service Life ◽  
Low Cycle Fatigue ◽  
Damage Model ◽  
Mechanical Damage ◽  
Damage Mechanism ◽  
Modern Trend ◽  
Cold Spot ◽  
Chromium Alloy ◽  
Cycle Fatigue ◽  
Service Environment

Delayed unit coker drums operate in a severe service environment that precludes long term reliability due to excessive shell bulging and cracking of shell joint and shell to skirt welds. Thermal fatigue is recognized as the leading damage mechanism and past work has provided an idealized description of the thermo-mechanical mechanism via local hot and cold spot formation to quantify a lower bound life estimate for shell weld failure. The present work extends this idealized thermo-mechanical damage model by evaluating actual field data to determine a potential upper bound life estimate. This assessment also provides insight into practical techniques for equipment operators to identify design and operational opportunities to extend the service life of coke drums for their specific service environments. A modern trend of specifying higher chromium and molybdenum alloy content for drum shell material in order to improve low cycle fatigue strength is seen to be problematic; rather, the use of lower alloy materials that are generally described as fatigue tough materials are better suited for the high strain-low cycle fatigue service environment of coke drums. Materials such as SA 204 C (C – ½ Mo) and SA 302 B (C – Mn – ½ Mo) or SA 302 C (C – Mn – ½ Mo – ½ Ni) are shown to be better candidates for construction in lieu of low chromium alloy steel materials such as SA 387 grades P11 (1¼ Cr – ½ Mo), P12 (1 Cr – ½ Mo), P22 (2¼ Cr – 1 Mo) and P21 (3 Cr – 1 Mo).

scholarly journals A Methodology for the Application of Virtual Evaluation Methods within the Design Process of Cold Forged Steel Pinions

2019 ◽  
Vol 1 (1) ◽  
pp. 3451-3460 ◽  
Author(s):  
Andreas Rohrmoser ◽  
Björn Heling ◽  
Benjamin Schleich ◽  
Christoph Kiener ◽  
Hinnerk Hagenah ◽  
...  
Keyword(s):  
Service Life ◽  
Design Process ◽  
Evaluation Methods ◽  
Cold Forging ◽  
Machining Processes ◽  
Short Service Life ◽  
Productive Process ◽  
Machine Elements ◽  
The Cost ◽  
Operational Behaviour

AbstractGears are essential machine elements in the drivetrain and transmission technology. The operational behaviour of a gear pairing is influenced by the design of the gear kinematics as well as the component properties. With regard to an improvement of performance and service life, the targeted modification of tooth geometry and component properties offers a promising approach. Thus, the achievable geometric and mechanical component properties are influenced by the manufacturing process, which must be taken into account in the design process. The application of virtual evaluation methods is suitable for this purpose. For the manufacturing of steel gears, cold forging provides the potential of achieving beneficial mechanical properties in a highly productive process. Major challenges for the industrial application are the short service life of the cost- intensive tools and the low geometric accuracy in comparison to machining processes. Within this study the design of the tooth geometry as well as the associated forming tool are investigated. The aim is to derive recommendations regarding an optimization of the resulting component properties and operational behaviour.

Probabilistic Structural Integrity Analysis of Reactor Pressure Vessels During Pressurized Thermal Shock Events

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Koichi Masaki ◽  
Jinya Katsuyama ◽  
Kunio Onizawa
Keyword(s):  
Crack Initiation ◽  
Thermal Shock ◽  
Structural Integrity ◽  
Fracture Probability ◽  
Pressure Vessels ◽  
Sensitivity Analyses ◽  
Conditional Probabilities ◽  
Integrity Assessment ◽  
Pressurized Thermal Shock ◽  
Reactor Pressure

To apply a probabilistic fracture mechanics (PFM) analysis to the structural integrity assessment of a reactor pressure vessel (RPV), a PFM analysis code has been developed at JAEA. Using this PFM analysis code, pascal version 3, the conditional probabilities of crack initiation (CPIs) and fracture for an RPV during pressurized thermal shock (PTS) events have been analyzed. Sensitivity analyses on certain input parameters were performed to clarify their effect on the conditional fracture probability. Comparisons between the conditional probabilities and the temperature margin (ΔTm) based on the current deterministic analysis method were made for various model plant conditions for typical domestic older types of RPVs. From the analyses, a good correlation between ΔTm and the conditional probability of crack initiation was obtained.

Strength Criteria Versus Plastic Flow Criteria Used in Pressure Vessel Design and Analysis1

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Xian-Kui Zhu
Keyword(s):  
Plastic Flow ◽  
Pressure Vessel ◽  
Yield Criterion ◽  
Pressure Vessels ◽  
Burst Pressure ◽  
Thin Wall ◽  
Strength Criteria ◽  
Integrity Assessment ◽  
Ductile Materials ◽  
Strength Design Criteria

This paper presents a critical comparison of the traditional strength criteria and the modern plastic flow criteria used in the structural design and integrity assessment of pressure vessels. This includes (1) a brief review of the traditional strength criteria used in the ASME Boiler and Pressure Vessel (B&PV) Code, (2) a discussion of the shortcomings of the traditional strength criteria when used to predict the burst pressure of pressure vessels, (3) an analysis of challenges, technical gaps, and basic needs to improve the traditional strength criteria, (4) a comparison of strength theories and plasticity theories for ductile materials, (5) an evaluation of available plastic flow criteria and their drawbacks in prediction of burst pressure of pressure vessels, (6) a description of a newly developed multiaxial yield criterion and its application to pressure vessels, and (7) a demonstration of experimental validation of the new plastic flow criterion when used to predict the burst pressure of thin-wall pressure vessels. Finally, recommendations are made for further study to improve the traditional strength design criteria and to facilitate utilization of the modern plastic flow criteria for pressure vessel design and analysis.

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