Long term prediction of pipeline corrosion under tropical seabed sediment

The corrosion of pipeline steels buried under seabed sediment is not fully predictable, since there are many parameters affecting the pipeline at different degrees. In relation to that, corrosion growth predictive model based on long term experimental study is of great demand to assist in making sui...

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Main Author:	Albshir Budiea, Ahmed Mokhtar
Format:	Thesis
Language:	English
Published:	2015
Subjects:	TA Engineering (General) Civil engineering (General)
Online Access:	http://eprints.utm.my/id/eprint/54719/1/AhmedMokhtarAlbshirBudieaPFKA2015.pdf
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spelling	my-utm-ep.547192020-11-03T09:11:41Z Long term prediction of pipeline corrosion under tropical seabed sediment 2015-07 Albshir Budiea, Ahmed Mokhtar TA Engineering (General). Civil engineering (General) The corrosion of pipeline steels buried under seabed sediment is not fully predictable, since there are many parameters affecting the pipeline at different degrees. In relation to that, corrosion growth predictive model based on long term experimental study is of great demand to assist in making suitable pipeline integrity decisions. Therefore, research has been conducted to investigate the metal loss behaviour and corrosion mechanism of pipeline steel under seabed sediment conditions. Then, this study developed a predictive model for corrosion under seabed sediment and highlighted corrosion parameters which presented in tropical climate. Two corrosion models were proposed; one based on the results of a long term exposure of steel coupons to the real field condition. Furthermore, another descriptive model was developed using response surface methodology. The most common applied model used to predict corrosion loss is the power law model (P = ktn), where t is exposure time, and k and n are constant regression of the sediment parameters. Carbon steel coupons were buried in seabed sediment up to two years period. The sediment samples were analysed for its contents and properties. The descriptive model was constructed with aid of Statistica 6.0 software for the data obtained from the laboratory experiment. The results were analysed using statistical methods such as correlation test analysis (CTA), principal component analysis (PCA), multiple linear regression (MLR) and ANOVA (analysis of variance). From the analysis, the extraction of sediment variables related to k and n were successfully obtained. In order to get the best fit of predictive model, the extracted variables are modelled using MLR and embedded in the power law equation. Good curve fitting results are obtained between the actual test data and the proposed models. With consideration of pipelines integrity, the prediction of metal loss due to corrosion in SBS environment using the developed power-law model is considered satisfactory with R2 score of 0.76. The corrosion model based on data from the laboratory has yielded reasonable prediction of metal mass loss with R2 score of 0.83. Noticeably, several sediment factors play an important role in corrosion process and thus determine the corrosion severity. Corrosion growth models have been developed and proposed to predict corrosion progress for steel pipelines buried under seabed sediment. This research has introduced innovative ways to model the corrosion growth for seabed sediment environment. Moreover, intensive statistical analysis has been utilised to determine the level of influence of sediment parameters towards corrosivity. The models enable the prediction of metal mass loss, thus assessing the corrosivity of seabed sediment condition for Malaysian tropical climate. 2015-07 Thesis http://eprints.utm.my/id/eprint/54719/ http://eprints.utm.my/id/eprint/54719/1/AhmedMokhtarAlbshirBudieaPFKA2015.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:94315 phd doctoral Universiti Teknologi Malaysia, Faculty of Civil Engineering Faculty of Civil Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TA Engineering (General) Civil engineering (General)
spellingShingle	TA Engineering (General) Civil engineering (General) Albshir Budiea, Ahmed Mokhtar Long term prediction of pipeline corrosion under tropical seabed sediment
description	The corrosion of pipeline steels buried under seabed sediment is not fully predictable, since there are many parameters affecting the pipeline at different degrees. In relation to that, corrosion growth predictive model based on long term experimental study is of great demand to assist in making suitable pipeline integrity decisions. Therefore, research has been conducted to investigate the metal loss behaviour and corrosion mechanism of pipeline steel under seabed sediment conditions. Then, this study developed a predictive model for corrosion under seabed sediment and highlighted corrosion parameters which presented in tropical climate. Two corrosion models were proposed; one based on the results of a long term exposure of steel coupons to the real field condition. Furthermore, another descriptive model was developed using response surface methodology. The most common applied model used to predict corrosion loss is the power law model (P = ktn), where t is exposure time, and k and n are constant regression of the sediment parameters. Carbon steel coupons were buried in seabed sediment up to two years period. The sediment samples were analysed for its contents and properties. The descriptive model was constructed with aid of Statistica 6.0 software for the data obtained from the laboratory experiment. The results were analysed using statistical methods such as correlation test analysis (CTA), principal component analysis (PCA), multiple linear regression (MLR) and ANOVA (analysis of variance). From the analysis, the extraction of sediment variables related to k and n were successfully obtained. In order to get the best fit of predictive model, the extracted variables are modelled using MLR and embedded in the power law equation. Good curve fitting results are obtained between the actual test data and the proposed models. With consideration of pipelines integrity, the prediction of metal loss due to corrosion in SBS environment using the developed power-law model is considered satisfactory with R2 score of 0.76. The corrosion model based on data from the laboratory has yielded reasonable prediction of metal mass loss with R2 score of 0.83. Noticeably, several sediment factors play an important role in corrosion process and thus determine the corrosion severity. Corrosion growth models have been developed and proposed to predict corrosion progress for steel pipelines buried under seabed sediment. This research has introduced innovative ways to model the corrosion growth for seabed sediment environment. Moreover, intensive statistical analysis has been utilised to determine the level of influence of sediment parameters towards corrosivity. The models enable the prediction of metal mass loss, thus assessing the corrosivity of seabed sediment condition for Malaysian tropical climate.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Albshir Budiea, Ahmed Mokhtar
author_facet	Albshir Budiea, Ahmed Mokhtar
author_sort	Albshir Budiea, Ahmed Mokhtar
title	Long term prediction of pipeline corrosion under tropical seabed sediment
title_short	Long term prediction of pipeline corrosion under tropical seabed sediment
title_full	Long term prediction of pipeline corrosion under tropical seabed sediment
title_fullStr	Long term prediction of pipeline corrosion under tropical seabed sediment
title_full_unstemmed	Long term prediction of pipeline corrosion under tropical seabed sediment
title_sort	long term prediction of pipeline corrosion under tropical seabed sediment
granting_institution	Universiti Teknologi Malaysia, Faculty of Civil Engineering
granting_department	Faculty of Civil Engineering
publishDate	2015
url	http://eprints.utm.my/id/eprint/54719/1/AhmedMokhtarAlbshirBudieaPFKA2015.pdf
_version_	1747817710485504000

Long term prediction of pipeline corrosion under tropical seabed sediment

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