Failure Analysis of α-MDEA Air-Cooled Heat Exchanger of CO2 Removal Unit Based on the Semiquantitative Risk-Based Inspection Method

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Hamid Reza Lashgari ◽  
Amir Hanaei ◽  
A. R. Adeli
Keyword(s):  
Corrosion Damage ◽  
Damage Mechanism ◽  
Co2 Corrosion ◽  
Failure Behavior ◽  
Co2 Removal ◽  
Inspection Planning ◽  
Inspection Method ◽  
Calculation Results ◽  
Mitigation Methods ◽  
Air Cooled Heat Exchanger

Risk-based inspection program (RBI) is a decision making techniques for providing refineries and petrochemical plants with an effective and appropriate inspection planning. The aim of the present study is to analyze failure behavior and risk ranking of α-MDEA fin/fan cooler of CO2 removal unit based on API 581 in order to find out the reason(s) of tubes failure. According to previous experience in similar plant, risk calculation results and conducted inspection activity by using RFT eddy current technique, CO2 corrosion damage mechanism was identified as a main reason of tubes failure. In next step, process key variable, prevention/mitigation methods and inspection planning programs were determined so as to minimize the similar failure behavior in the rest of the lean amine air-cooled heat exchangers of CO2 removal unit.

Experimental Study and Numerical Simulation for Explosion and Phenomena of RC Slabs

2014 ◽  
Vol 501-504 ◽  
pp. 1096-1103
Author(s):  
Hong Xiao Wu ◽  
Hao Zhe Xing ◽  
Zhi Fang Yan
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Loading Condition ◽  
Damage Mechanism ◽  
Failure Characteristics ◽  
Explosion Pressure ◽  
Concrete Plate ◽  
Solid Models ◽  
Calculation Results ◽  
Rc Slabs

The blast impact dynamic experiment of reinforced concrete rectangular plate with simply supported boundary conditions was performed using explosion pressure simulator. With 3-D FEM software LS-DYNA, the separate solid models of concrete and steel were established and 3-D FEM dynamic analysis of the experiment process was carried out. Compared calculation results to experiment results synthetically, the damage mechanism and failure characteristics of reinforced concrete plate under explosion impact loading condition were got and it is also verified that the H-J-C model can approximately simulate the concrete properties well under explosion impact loading condition.

Hot corrosion damage mechanism of Ti6Al4V alloy in marine environment

Vacuum ◽  
2021 ◽  
pp. 110350
Author(s):  
Hulin Wu ◽  
Ping Gong ◽  
Suying Hu ◽  
Lin Xiang ◽  
Enlei Wang ◽  
...  
Keyword(s):  
Marine Environment ◽  
Hot Corrosion ◽  
Corrosion Damage ◽  
Damage Mechanism ◽  
Ti6al4v Alloy

Mitigation of Annulus Pressure Buildup in Offshore Gas Wells by Determination of Top of Cement

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Alex W. Mwang’ande ◽  
Hualin Liao ◽  
Long Zeng
Keyword(s):  
Field Data ◽  
Gas Wells ◽  
Gas Well ◽  
Pressure Buildup ◽  
Cheap Method ◽  
Calculation Results ◽  
Sustained Casing Pressure ◽  
Casing Pressure ◽  
Mitigation Methods

Annulus pressure buildup (APB) is still a serious problem in offshore gas wells, which threatens the safety of wells for the entire phases of drilling, completion, and production. The existing methods for mitigating APB are technically complex and highly costly. Setting top of cement (TOC) below the outer casing shoe to mitigate APB is easy to implement and can significantly reduce costs. However, there are no unified methods of determining TOC for this purpose. Nevertheless, existing petroleum standards give ambiguous regulations on the setting of TOC. This article brings a new and cheap method of mitigating APB by determining best TOC settings using a mathematical model for calculating APB from both annulus fluid expansion (AFE) and sustained casing pressure (SCP). Field data from gas well X are inputted to the model to describe how it serves this purpose. Calculation results for well X show that setting TOC's above and below the upper casing shoes for production and intermediate casings annuli, respectively, can greatly avoid the problem of APB and the costs associated with the existing mitigation methods. This technique can be used to other wells following the same procedures. The developed model reduced greatly the ambiguity of TOC determination as it helps to get the clear TOC combinations that control APB at the lowest cost of well construction while maintaining good and safe well operation.

The Research on the Stress Analysis of Overhead Steam Pipeline

2020 ◽  
Author(s):  
Zhe Pu ◽  
Jielu Wang ◽  
Bin Ren ◽  
Pan Song ◽  
Fan Zhao
Keyword(s):  
High Temperature ◽  
Stress Analysis ◽  
Industrial Production ◽  
Inspection Method ◽  
Steam Pipeline ◽  
Periodic Inspection ◽  
Whole Plant ◽  
Calculation Results ◽  
Long Time ◽  
Physical And Chemical

Abstract Industrial production is accompanied by a large number of physical and chemical reactions. Steam, whose heat was often used to carry out various production activities, is a common medium in industrial production. Steam pipeline has the characteristics of high temperature and high pressure. The pipeline has been in service at high temperature for a long time, which is prone to metal material degradation such as graphitization and spheroidization. Cause of the expansion of steam pipeline after heating, the natural compensation structure is generally adopted in the whole plant pipe gallery. In recent years, the accidents of steam pipeline occurred frequently, so we must pay more attention to the safety of steam pipeline. Periodic Inspection Regulation for Industrial Pressure Piping (TSG D7005-2018) explicitly requires stress analysis and checking in some cases to determine the safety of the pipeline. The traditional inspection method adopts a random sampling model which has the risk of over inspection and missing inspection. Taking a whole plant steam pipeline as an example, this paper introduced the stress check criterion of pipeline in ASMEB31.3.The model of the pipeline was established by the software, and the stress state and displacement of each node of the pipeline were calculated. According to the calculation results, a targeted inspection scheme was established and effective data support was provided for the regular inspection of steam pipeline.

scholarly journals Research on the Corrosion Damage Mechanism of Concrete in Two Freeze–Thaw Environments

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Xianhua Yao ◽  
Min Zhang ◽  
Junfeng Guan ◽  
Lielie Li ◽  
Weifeng Bai ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Erosion Resistance ◽  
Corrosion Damage ◽  
Damage Mechanism ◽  
Resistance Coefficient ◽  
Dynamic Elastic Modulus ◽  
Freeze Thaw ◽  
Environment Temperature ◽  
Performance Deterioration ◽  
Air Void

This study aims to investigate the effects of two freeze–thaw environments (i.e., maintenance freeze-thaw (MFT) environment and immersion freeze-thaw (IFT) environment) on the durability performance, deterioration rules, and mechanisms of concrete. In MFT, the concrete specimens were firstly cured in the standard curing environment (temperature, 20 ± 3, humidity, not less than 95%, and ages, 28 d) and then were carried out in freeze–thaw environment, while in IFT, the concrete specimens were firstly cured in the salt (NaHCO3, NaCl, and Na2SO4) immersion environment for 90 d and then were carried out in freeze–thaw environment. In this study, the damage features, relative dynamic elastic modulus, mass changes, and erosion-resistance coefficient of concrete have been measured. Thereafter, using the scanning electron microscopy (SEM) and the mercury intrusion porosimetry (MIP), the air-void structure parameters and the microstructures have been measured, respectively. The results show that the relative dynamic elastic modulus and the erosion-resistance coefficient of the compressive strength of the concrete in the IFT environment are, respectively, 14.3% and 21.0% higher than those of the concrete in the MFT environment. In addition, the results of the microstructure analyses show that the corrosion damages of the concrete are mainly caused by the combined action of the corrosion products of ettringite and freeze–thaw environment. However, the damage to the concrete in the MFT environment is more serious than that in the IFT environment. The results of the MIP analysis show that the harmful pore value for the concrete in the MFT environment is almost two times larger than that for the concrete in the IFT environment.

Temporal Variability in Corrosion Modeling and Reliability Updating

2006 ◽  
Vol 129 (4) ◽  
pp. 265-272 ◽  
Author(s):  
Daniel Straub ◽  
Michael Havbro Faber
Keyword(s):  
Corrosion Rate ◽  
Temporal Variability ◽  
Reliability Assessment ◽  
Corrosion Process ◽  
Quantitative Modeling ◽  
Co2 Corrosion ◽  
Inspection Planning ◽  
Corrosion Loss ◽  
Temporal Models ◽  
Time Invariant

Many parameters influencing corrosion degradation are time variant and the corrosion process is thus subject to temporal variability, the real characteristics of which are commonly neglected in reliability assessment. After a short overview on the quantitative modeling of corrosion loss, a comparison is made between different temporal models of corrosion degradation and the consequences of applying an inappropriate model are investigated. The effect of temporal variability is then investigated in detail and illustrated in an example considering CO2 corrosion in pipelines. It is demonstrated how the time-variant corrosion process can be consistently represented by time-invariant random variables, using equivalent values of the corrosion rate. Finally, the influence of temporal variability on reliability updating following inspections is investigated and it is shown how this effect can be accounted for in inspection planning.

Development of Risk-Based Maintenance Software for Gas Turbines

2007 ◽  
Author(s):  
Tomoharu Fujii ◽  
Terutaka Fujioka ◽  
Chris Ablitt ◽  
Julian Speck ◽  
Brian Cane
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Damage Mechanism ◽  
Risk Assessments ◽  
Inspection Planning ◽  
Risk Matrix ◽  
Hot Gas ◽  
Path Component ◽  
Software Risk ◽  
Maintenance And Inspection

Risk-based maintenance software has been developed to perform risk-based maintenance and inspection planning on gas turbine hot gas path components. The software allows the user to easily prepare a risk matrix, plotting every active damage mechanism for each hot gas path component. Based on the result of the risk assessments the components can be ranked, allowing inspection plans to be focused and prioritized and aiding the user to identify the most appropriate and effective risk mitigating activity within the software. Risk assessments are performed on a component-by-component basis, with the software’s scope including all combustor and turbine hot gas path components. The software also contains comprehensive help documents to aid the user in identifying and assessing peculiar damage mechanisms and prescribing the most effective inspection methods for gas turbines.

STOCHASTIC VISCOUS-DAMAGE CONSTITUTIVE MODEL FOR CONCRETE

2013 ◽  
Vol 07 (03) ◽  
pp. 1350027
Author(s):  
JIE LI ◽  
QIAOPING HUANG
Keyword(s):  
Damage Model ◽  
Damage Mechanism ◽  
Failure Behavior ◽  
Strain Rates ◽  
Rate Dependency ◽  
Rate Dependent ◽  
Proposed Model ◽  
Model Predictions ◽  
Damage Constitutive Model ◽  
Stochastic Damage

A new rate-dependent stochastic damage model for the dynamic modeling of concrete is presented in the paper. This model is formulated on the basis of the stochastic damage model, from which, the static stochastic evolution of damage is strictly derived. Then, rate dependency of concrete is included by means of viscous-damage mechanism. The model predictions are tested against experimental results on concrete specimens that cover different strain rates. The results demonstrate the proposed model may predict dynamic failure behavior of concrete quite well.

scholarly journals REDUCING THE FORCE RESISTANCE OF STEEL COLUMNS IN INDUSTRIAL BUILDINGS WITH CORROSION DAMAGE DURING OPERATION

2020 ◽  
Vol 8 (4) ◽  
pp. 9-13
Author(s):  
Nina Buzalo ◽  
Ivan Gontarenko ◽  
Boris Chernykhovsky
Keyword(s):  
Experimental Study ◽  
Corrosion Damage ◽  
Building Structure ◽  
Safe Operation ◽  
Metal Structures ◽  
Steel Columns ◽  
Industrial Buildings ◽  
Calculation Results

When conducting inspections of metal structures of industrial buildings, one of the most characteristic damages is revealed - corrosion. To assess the degree of serviceability and the possibility of further safe operation of a building structure or a building and structure, it is necessary to correctly assess the danger of corrosion damage and determine the possibility of further operation. To assess the strength resistance of damaged structures, it is necessary to correctly assess the danger of corrosion damage and determine the possibility of further operation. For this purpose, an experimental study of columns with simulated corrosion damage was carried out and compared with the calculation results according to regulatory recommendations.

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