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Teevens P.J.,Broadsword Corrosion Engineering Ltd. | Khera A.,Allied Engineers | Zhu Z.,Broadsword Corrosion Engineering Ltd.
ASME 2013 India Oil and Gas Pipeline Conference, IOGPC 2013 | Year: 2013

Contaminants such as CO2, H2S and O2 in water-wet liquid and gas pipelines create an aggressive environment conducive to facilitating internal corrosion. During pipeline operations, solids deposition, water accumulation, bacterial activities and improper chemical inhibition aggravate the internal corrosion attack. For assessing the threat of internal corrosion, the petroleum industry currently has only three integrity validation tools at its disposal. These are Pressure Testing, In-line Inspection (ILI) and Internal Corrosion Direct Assessment (ICDA). To enhance pipeline integrity for piggable and nonpiggable pipelines, NACE International has developed and published a variety of industry consensus Standard Practices for the ICDA protocols to predict time-dependent internal corrosion threats for various petroleum products in both offshore and onshore under sweet or sour environments. These NACE International ICDA Standards include: • SP0206-2006 "ICDA Methodology for Pipelines Carrying Normally Dry Natural Gas (DG-ICDA)" [1] • SP0208-2008 "ICDA Methodology for Liquid Petroleum Pipelines (LP-ICDA)" [2], • SP0110-2010 "Wet Gas ICDA Methodology for Pipelines (WG-ICDA)" [3] • Multiphase flow (MP-ICDA) is under development with TG-426 and will be released in 2013. • Process Piping (PP-ECDA, Above Ground) is in its early stages of development with the release not likely before 2015. • Process Piping (PP-ECDA, Buried) is in its early stages of development with the release not likely before 2015. • Process Piping (PP-ICDA) for various service environments is in its early stages of development with the release not likely before 2015. All ICDA protocols are a structured, iterative integrity assessment process, consisting of the following four steps: Preassessment, Indirect Inspection, Detailed Examination and Postassessment. Most importantly, unlike ILI and pressure testing, all the ICDA standards require a mandatory root cause analysis and a go forward mitigation plan to arrest the corrosion processes being encountered. This paper reviews the following case studies: LP-ICDA for a crude oil pipeline and WG-ICDA for a high pressure gas pipeline with free water and condensate. ICDA is applicable for dry gas systems too but due to limiting length of this paper, the dry gas case study is not detailed. This paper will be useful for the pipeline operators to provide guidance in identifying locations at which corrosion activity has occurred, is occurring, or may likely occur in the future under a series of pre-defined operating conditions. Copyright © 2013 by ASME. Source


Teevens P.,Broadsword Corrosion Engineering Ltd. | Tajallipou N.,Broadsword Corrosion Engineering Ltd.
Annual Conference of the Australasian Corrosion Association 2014: Corrosion and Prevention 2014 | Year: 2014

The pipeline industry in the developed world is increasingly experiencing more intense and protracted regulatory, public and environmental scrutiny than ever before. It has been likened to the intense public debate about the nuclear energy industry of the 1990's. Pipeline failures, leaks, ruptures, environmental pollution from releases, greenhouse gas emissions and the unfortunate loss of human lives have all culminated in a growing and sensationalized, media-promoted public distrust of pipeline operators in general. Focal to the argument against pipeline proliferation and associated system expansions, is the widening perception that pipeline operators have inconsistent and ineffective pipeline integrity management programs. Since most upstream production pipelines and a significant percentage of midstream transmission lines fail due to internal corrosion, it is absolutely necessary that technical competency in corrosion engineering and corrosion management systems, including the personnel charged with implementing them, are non-negotiable attributes with respect to regulatory program expectations. This paper discusses the benefits and successes attained by methodically defining internal pipeline corrosion susceptibility through the 4-step Internal Corrosion Direct Assessment (ICDA) process for wet gas and multiphase fluids. The advantages gained from following the new and pending NACE International Standard Practices for DA, regardless of whether the line is piggable or not, result in the operator being confidently able to define the root-cause of their problem, the degradation rate or severity of internal corrosion and the implementation of an appropriate verifiable mitigation plan. This process results in elevating pipeline reliability, safety and operator confidence which can be translated into reducing the public perception that pipeline operators are not proactively preventing corrosion-initiated releases. Source


Arumugam S.,Broadsword Corrosion Engineering Ltd. | Tajallipour N.,Broadsword Corrosion Engineering Ltd. | Teevens P.J.,Broadsword Corrosion Engineering Ltd.
NACE - International Corrosion Conference Series | Year: 2014

This paper presents a new approach to model the growth mechanism of the sweet corrosion product (i.e. iron carbonate scale) and to study the influence of the corrosion product morphology on the uniform corrosion rates. Corrosion rates were defined as the iron ion flux rate leaving the metal surface which is governed by the thickness and volumetric porosity of the corrosion product (scale). Nucleation and crystal growth were treated as the two committed steps in forming the scale. The population number and the critical size of the iron carbonate nuclei were determined using the classical nucleation theory. Supersaturation level was quantified by the effusion of iron ions from the metal surface and infusion of carbonate ions from the bulk solution. Crystal growth, followed by nucleation and termination of the supersaturation condition, was modeled using a moving boundary approach solving Fick's diffusion equations in spherical coordinates. Under stagnant conditions, the formed scale layer thickness and the volumetric porosity were obtained based upon the crystal shape and size. Also, the time-dependent iron ion flux/corrosion rates were predicted. Further, the effects of operating parameters such as pressure and temperature on the competition between the nucleation rate and the growth rate of crystal nuclei were examined. © 2014 by NACE International. Source


Arumugam S.,Broadsword Corrosion Engineering Ltd. | Tajallipour N.,Broadsword Corrosion Engineering Ltd. | Teevens P.J.,Broadsword Corrosion Engineering Ltd.
NACE - International Corrosion Conference Series | Year: 2014

The sour corrosion product (i.e. iron sulphide) exhibits different morphologies under different operating conditions and possess different crystal structures and oxidation states. Developing a model to understand the growth mechanism of different forms of the sour corrosion product is essential in predicting corrosion rates and mitigating scale formation in sour environment. This paper presents a new approach wherein the nanocrystalline iron sulphide (mackinawite) scale formation is modeled by the nucleation and growth of the scale crystals. Ignoring any solid state reactions that could form iron sulphide in undersaturated solutions, the supersaturation level quantified the extent of nucleation followed by diffusion controlled crystal growth. The scale morphology in terms of the volumetric porosity and their influence on the predicted sour corrosion rates were studied under stagnant conditions. © 2014 by NACE International. Source


Fardisi S.,Broadsword Corrosion Engineering Ltd. | Tajallipour N.,Broadsword Corrosion Engineering Ltd. | Teevens P.J.,Broadsword Corrosion Engineering Ltd.
NACE - International Corrosion Conference Series | Year: 2012

A mechanistic model was developed to predict uniform corrosion rates in sour liquid petroleum pipelines. The model incorporates the transient chemical reactions which occur in the bulk of the corrosive fluid, the transport of the active species to and away from the surface, and the electrochemical reactions occurring at the surface of the metal. In addition, the technical complications of coupling a scale growth model applicable to multiple scale types such as FeCO 3 and FeS, with a corrosion simulation were discussed in detail. It was proposed to remedy these issues by separating the scale growth and corrosion modeling procedures. The results of examining scale formation can be stored in a correlated database to be imported later into the corrosion simulation using the approach presented in this paper. This method helped to incorporate the effect of FeS film growth on the variation of the corrosion rate. All the assumptions and simplifications of the model are discussed and shown to be appropriate for solving this problem. Several simulations were performed, and the predictions were compared with available experimental data in different operating conditions. In general, results agreed well with the corresponding experimental values tending to justify the approach presented. ©2012 by NACE International. Source

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