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Addressing Several Critical Issues on the Mechanism Co2 Corrosion and its Inhibition

Paper Number: 105
Author/s: B. Kinsella
Organisation: Curtin University

Abstract

This paper for the PF Thompson memorial lecture concerns CO2 corrosion of carbon steel and its inhibition during petroleum production. Important aspects of the mechanism of CO2 corrosion are covered together with significant advances in understanding corrosion inhibitor mechanism. Some gaps in the mechanism of corrosion inhibitors and areas considered worthy of future research are mentioned. Test methods to evaluate corrosion inhibitors are also covered. The contributions made in these areas of corrosion science by colleagues, former colleagues and PhD students are presented.

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The Probing of Pipeline Localized Corrosion Using a Novel Designed Ring Pair Electrical Resistance Sensor Array

Paper Number: 41
Author/s: Yesen Zhu1, Yi Huang1,*, Yunze Xu1, Xiaona Wang2 & Shide Song3
Organisation: 1School of Naval Architecture Dalian University of Technology, Dalian, Liaoning Province, China 2School of Physics Dalian University of Technology, Dalian, Liaoning Province, China 3School of Civil Engineering Dalian University of Technology, Dalian, Liaoning Province, China

Abstract

In this paper, a new method has been proposed to study the localized corrosion of pipeline different areas based on the multiple ring pair electrical resistance sensor (RPERS) array. The sensor array arranged multiple sets of ring pairs along the flow direction, and each ring pair was divided into six segments along the circumference. The sensor system not only can monitor the circumferential corrosion depth of the pipe, but also can monitor the corrosion depth along the flow direction. Based on the new sensor system, the corrosion behavior of the welding structure at the pipeline elbow location was studied. The corrosion propagation of the different welding zones, i.e. base metal (BM), heat affected zone (HAZ) and weld metal (WM) at the pipeline welding area, was on-line monitored by the RPERS array. The surface characterization was conducted to observe the surface morphology and the compositions of the corrosion scales. The SEM images show that dense and protective film formed at 60 in the brine solution with a pH 6.6. The measurement results demonstrate that the decrease of the corrosion rates at the WMs area was nearly one day delayed than those of the BMs and the HAZs, which is related to the inhibition effect of the acicular ferrite and the widmanstatten ferrite to generate a dense FeCO3 layer.

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Corrosion Behaviour of Ni-Cr Alloys in Oxygen at High Temperature

Paper Number: 68
Author/s: Y.L. Hsu, Y. Xie, J. Zhang
Organisation: School of Materials Science and Engineering, University of New South Wales, Sydney NSW 2052, Australia

Abstract

To meet an increased energy demand, it is necessary to increase steam turbine operating temperature of coal-fired power plant from conventional practice of 540°C to ultra/advanced ultra-supercritical practice over 700°C. Because of this temperature increase, traditional ferritic/martensitic and austenitic steels cannot survive. Instead, nickel- base alloys have to be used because of their superior creep strength and steam oxidation resistance at high temperatures.

In this work, oxidation behaviour of binary Ni-Cr alloys with Cr concentration from 5 to 30 wt% was investigated in 20%O2-80%Ar gas for up to 310 h reaction at 650, 700 and 800 °C. All samples were electro-polished to avoid the accelerated alloy Cr diffusion due to the effect of surface cold work. The results showed that for Cr concentration lower than 30 wt%, all alloys formed a multi-layered oxide scale, together with an internal oxidation zone. Increasing Cr concentration to 25 wt% led to the formation of a chromia band at the reaction front and a significant reduction in internal oxidation zone. When Cr concentration reached 30 wt%, a thin protective chromia scale was observed at all temperatures. The effects of chromium and temperature on oxide formation were discussed based on reaction kinetics and diffusion analysis during high temperature reaction process.

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The study of water-line corrosion in static and dynamically flowing electrolytes using multi-electrode sensor in combination with electrical resistance method

Paper Number: 34
Author/s: Yunze Xu1, 2, Mike Yongjun Tan1* and Yi Huang2
Organisation: 1School of Engineering and Institute for Frontier Materials Deakin University, 75 Pigdons Road, Waurn Ponds, VIC 3216, Australia 2School of Naval Architecture and Ocean Engineering, Dalian University of Technology, 2 LingGong Road, Dalian, Liaoning 116024, China

Abstract

In this work, a new sensor system was developed based on an integrated multi-electrode technique in conjunction with an electrical resistance (ER) method. This new method has allowed galvanic currents flowing among the multi-electrodes and the total metal loss simultaneously measured. On the basis of the new designed 10 elements sensor system, the water-line corrosion in both static and flowing electrolytes were studied. It is found that in the static 3% NaCl aqueous condition, the major anodic area is located at the bot
tom of the sensor suggesting the water-line corrosion is controlled by the oxygen differential cell. However, in the flowing condition, the major anodic areas were close to the water line and the bottom region transferred to a cathodic area, suggesting that the flowing of the electrolyte is an important influence factor of the water-line corrosion. From the comparison of the galvanic current and the ER measurement results, it is seen that galvanic corrosion is the main contribution of the water-line corrosion in both static and flowing electrolytes.

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No one cares about the paint – a specifier’s perspective

Paper Number: 45
Author/s: O. Duyvestyn & K. Wilson
Organisation: Advanced Materials & Strategic Asset Management - AECOM Australia Pty Ltd

Abstract

This presentation will light-heartedly discuss topics to specifically address issues that are of interest to protective coating manufacturers and will offer a unique insight into the inner workings of large engineering firms with respect to materials selection and the preparation of protective coating specifications. An explanation will be offered why some specifiers in large engineering firms often get it so wrong, why there is limited attention to detail and where the coating specification ranks in terms of importance within the big picture of the project at hand. The presentation also high-lights how the interaction with coating manufacturers is often perceived, if and how they can influence the independent specifier and discusses the real importance of a manufacturer having their product listed in project specifications. Finally, the presentation addresses the relationship between the specifier and their asset owner client, what drives that relationship and where coating manufacturers fit in that relationship. With this presentation, the presenters intend to provoke a debate between the different parties that need to come together to deliver an outcome that is ultimately in the interest of the end user of applied protective coating systems rather than other parties involved in a new construction or maintenance project.

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A Two-Stage Corrosion Protection System for Reinforced Concrete Structures

Paper Number: 21
Author/s: D. Whitmore1 & D. Simpson2
Organisation: Vector Corrosion Technologies Ltd.1&2

Abstract

Electrochemical corrosion protection techniques including impressed current cathodic protection (ICCP), galvanic corrosion protection (GCP) and electrochemical treatments (ECE and Re-Alk) are well known and widely used to protect reinforced concrete structures globally. Each of these techniques have inherent advantages and disadvantages which are also well known.

Two-stage corrosion protection systems combine or fuse two or more of these methods together into a single system. This simple, holistic approach can provide excellent corrosion protection. More importantly, this methodology achieves protection without the limitations associated with the individual techniques.

This paper describes the development, laboratory evaluation, field performance and implementation of two-stage corrosion protection systems which have fused impressed current, galvanic and electrochemical treatment systems together.

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Impregnation Technique Extends the Service Life of Post-Tensioned Bridges with Grout Defects

Paper Number: 20
Author/s: D. Whitmore
Organisation: Vector Corrosion Technologies Ltd

Abstract

Many bridges and other structures have been constructed using grouted post-tension (PT) tendons. Problems with grouting techniques and grout materials has resulted in grout voids, chloride contaminated grout, and segregated grout. Subsequently corrosion of the PT tendons can occur and some tendons have corroded to failure. Some of these failures have occurred within 6 to 17 years of construction.

This paper describes the problem and the development and implementation of a cost-effective corrosion mitigation technique used to mitigate the corrosion and extend the service life of post-tensioned bridges which have grout issues.

The technique utilizes the interstitial space between the wires to deliver a low viscosity impregnation material along the length of the PT tendon. Laboratory and field testing has confirmed the ability of the impregnation material to travel the full length of PT tendons in bridges.

When the corrosion resistant impregnation material is introduced into a PT tendon, it coats the tendon surfaces with a corrosion resistant film and soaks into the grout surrounding the strands providing additional corrosion protection. Testing shows that impregnation can reduce corrosion by over 90%.

This technique has been tested and used by the Florida Department of Transportation (FDOT) and Virginia Department of Transportation (VDOT) on a number of PT bridges. This paper will discuss the application of this technique on tendons of the I-95 / I-295 Interchange in Jacksonville, FL, the I-4 Connector in Tampa, FL, Ringling Bridge tendons (Sarasota, FL), Wonderwood over the Inter Coastal Waterway (Jacksonville, FL) and Varina-Enon Bridge, Richmond, VA.

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Flange Face Corrosion in Seawater and Hydrocarbon Environment Related to Gasket Material Selection

Paper Number: 40
Author/s: S Bond1, A Lattimer2 & P Welsford3
Organisation: The Flexitallic Group1, Houston, USA, Flexitallic UK Ltd2, Cleckheaton, UK & Flexitallic UK Ltd (Singapore Branch)3, Singapore

Abstract

Bolted flange joints in seawater and hydrocarbon services can be vulnerable to gasket degradation and flange face corrosion. In its document on corrosion management, the UK’s Energy Institute ranks corrosion as the second most frequent cause in initiating loss of hydrocarbon containment in offshore platforms, and highlights corrosion as a major threat to asset integrity and plant efficiency.

Flange face corrosion can be extremely difficult to detect prior to leakage leading to loss of valuable resources. The impact on the environment can also be a major concern as can the immediate safety of plant personnel. Replacement or remedial works often means unscheduled downtime, additional costs and reduced asset efficiency.

Despite its widely recognised importance to reduce the conditions for crevice and galvanic corrosion, the selection of gasket materials has been historically overlooked in the market until recently. The need for new material combinations has opened up new market opportunities for gasket manufacturers. Although traditional materials such as Graphite, Mica and PTFE have characteristics that can be very useful to flange applications, they do not have the qualities to offer optimum performance in the area of corrosion.

This presentation considers the anti-corrosion characteristics of spiral wound gasket materials traditionally used in seawater and hydrocarbon service and compares them to a new corrosion mitigating gasket material. The presentation will include details of application opportunities and case examples from use in both upstream and downstream oil and gas operations.

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Proposed Recommended Practice for Coating Dry Film Thickness Measurement Over Concrete

Paper Number: 58
Author/s: W Ward1, B McGuiness2 & W Villarosa1
Organisation: Papworths Construction Testing Equipment1, Sydney, Australia & Marine and Civil Maintenance2, Sydney, Australia

Abstract

Non-Destructive Testing [NDT] techniques used within or over concrete are less standardized than equivalent tests for Metal Substrates. Guidelines may differ between manufacturers, specifications and supplier details, limiting the effectiveness of NDT techniques for evaluation of concrete structures.

Coatings over concrete have similar requirements for surface preparation and coating application as coatings over steel, but the NDT and inspection equipment used for quality control are not as well understood for this application. Dry Film Thickness measurements over steel are heavily standardized within Australia, with AS 3894 offering guidance for their use on site and AS 1580.108 and AS 2331 being more general and lab focused respectively.

This paper will present a recommended practice, taking into consideration manufacturer, applicator and coating supplier recommendations for thickness measurement, along with existing standards for testing of coating thickness over steel. It will discuss Ultrasonic Pulse Echo (UPE) based tests for coating thickness and how they compare to destructive measurements. It will also consider limits and benefits of the UPE measurement technique.

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Further Observations on the Performance of Geomembrane Materials in Floating Cover Applications in Australia

Paper Number: 87
Author/s: P Vince
Organisation: WSP

Abstract

In 2011 Moore et al reported on the performance of polypropylene liners and covers in the South Australian potable water industry. It was found that this material suffered accelerated oxidation and premature failure when exposed to chlorinated and chloraminated potable water. Given that storage of potable water was the primary function of the liners and covers, diminished service life was of significant concern to asset owners. This paper provides an update on the water industry’s response to those issues. The performance of various geomembrane materials is reviewed based on published research, physical testing and site service. Testing methods are reviewed as to applicability. Asset owners have limited knowledge of the properties of active liners and covers and find it difficult to make investment decisions due to imprecise estimates of remaining life. Typical methods for evaluating the performance and remaining life of in service geomembrane liners and covers are proposed.