February 24, 2020

Join us in Houston June 14-18th for NACE CORROSION 2020, the world’s largest conference and exposition on corrosion, welcomes more than 6,000 attendees hailing from over 70 countries. This comprehensive technical conference is packed with 1,000+ hours of technical education all focused on the study, prevention, and control of corrosion. 

Stop by and visit us at Booth #922 to talk with industry experts about how Intertek can help solve your corrosion problems.

June 14-18, 2020
George R. Brown Convention Center
Houston, TX
Booth: 922

Conference Papers 

Cathodic Protection within Narrow Gaps of Offshore Wind Turbine Foundations 
George R. Brown Convention Center - Room 340 A
Author: David Buxton, Gareth John, Thomas Wewer (Innogy) and Petra Ernst (Midland Corrosion Services Ltd)

Abstract: Cathodic protection is routinely applied to the external surfaces of offshore wind turbine monopile foundations to minimise corrosion.  However, due to unplanned water exchange through cable entry seals, a small additional surface area, in a gap between the seal and the ‘cable entry hole’ through the steel monopile was exposed to flowing seawater. Cathodic protection calculations were undertaken to assess whether protection (either applied externally or externally and internally) could penetrate into the small gap and prevent corrosion.

In addition to the calculations, laboratory simulations were setup using apparatus to replicate, as far as possible, the gap between the cable entry seal and the monopile, thereby allowing testing of the extent that cathodic protection could “reach” inside the gap. A test matrix was developed to include both stagnant and flowing conditions and variable gap dimensions were performed, representative of the varying in-service conditions.

The paper will describe the results obtained including potential and current measurements, surface analysis, and the use of the results as input to the fatigue analysis for the monopile.

Development of Unified & Methodology Examining the Critical Pitting/Repassivation Potential and Temperature
George R. Brown Convention Center - Room 362 C
Authors: Richard Woollam, Daniel Betancourt, Jie Wen

Abstract: Standards ASTM G61 - used for Cyclic Potentiodynamic Polarization measurements, and G150 - used in Critical Pitting Temperature measurements, are commonly used to determine the susceptibility of corrosion resistant alloys to localized corrosion. The two methodologies utilize different, yet related, driving forces applicable to the process, namely the potential and temperature. This study sought to establish the relationship between the pitting potential from ASTM G61 and critical pitting temperature from ASTM G150, both of which are determined as the driving force, potential or temperature, is on the increase. ASTM G61 also establishes the repassivation potential as the potential is decreased. In this study, ASTM G150 is extended to define the repassivation temperature for a decreasing temperature. The “unified” approach was utilized to identify the transition of a material from passive to active and its return to passive. Laboratory experiments were performed with Alloy 2205 in Flue gas desulfurization (FGD) slurry.

Optimization of FGD Operating Conditions by Electrochemical Laboratory Testing Applied to Alloy UNS S32205 
George R. Brown Convention Center - Room 370 DF
Authors: Daniel Betancourt, Jie Wen, Steven Kung (EPRI), Craig Birkenfeld (Luminant)

Abstract: Flue gas desulfurization (FGD) systems are frequently used to remove SO2 from coal combustion at power plants. In systems where limestone is utilized, calcium chloride from the resulting slurry can be concentrated into a valuable byproduct. However, the concentrated slurry poses increased localized corrosion risk to the materials of construction in contact with exhaust/combustion stream. Cyclic Potentiodynamic Polarization (CPP) and Critical Pitting Temperature (CPT) present electrochemical methodologies which can be used to assess the relative risk of different conditions in the laboratory. However, the results of these techniques can be dependent on the details of the experimental protocol. In this study, the effect of slurry preparation, the potential scan rate, alloy conditioning time, and slurry acidity were examined. A conservative test protocol was developed based on the outcomes of the effects considered and the critical chloride concentration of Alloy 2205 was determined, enabling optimization of FGD operating conditions. 

Analysis of Corrosion Inhibitor Performance Curves Using Langmuir Adsorption Kinetics
George R. Brown Convention Center - Room 362 AB
Authors: Richard Woollam, Daniel Betancourt

Abstract: Many corrosion inhibitor performance tests track the corrosion rate over time utilizing electrochemical methods such as linear polarization resistance (LPR). In most of these tests only a portion of the test data gathered are utilized in the final analysis of the corrosion inhibitor performance, namely, the initial uninhibited corrosion rate and the final steady state inhibited corrosion rate, from these two results the corrosion inhibitor performance or efficiency is calculated. Unfortunately, in this approach only the start and end of the test are utilized while the transient response of the corrosion rate versus time curve is discarded. The following paper describes an analysis method using Langmuir adsorption kinetics to extract from the response curve not only the corrosion inhibitor efficiency, but also the adsorption and desorption rate constants.

Utilization of Adsorption Kinetics Rate Constants to Better Define Corrosion Inhibitor Availability
George R. Brown Convention Center - Room 362 AB
Authors: Richard Woollam, Daniel Betancourt

Abstract: The corrosion inhibitor availability model as defined in 2000 presents a simplified binary approach to corrosion inhibitor performance. In particular, the corrosion inhibitor is assumed to be active and fully effective from the instant it is injected to the instant it no longer injected. As a consequence, the 2000 availability model does not account for the transient performance of the corrosion inhibitor namely, the time required to reach steady state and the time required for the inhibitor to desorb or persistency. In the following paper Langmuir adsorption kinetics are utilized to analyze the corrosion inhibitor performance curve and based on the adsorption and desorption rate constants the 2000 corrosion inhibitor availability model is updated to better account for the short term/transient response of the corrosion inhibitor. In particular, an attempt is made to better define and quantify “persistency” of the corrosion inhibitor in terms of the desorption rate constant and the surface residence time.

Best Practices to Ensure Effective Pipeline Corrosion Management and Mistakes That Can be Avoided
George R. Brown Convention Center - Room 370 AC
Author: Leo Richards is a Principal Production Chemist at Intertek (P&IA), James Stott, Michael Horne, Simon Schapira

Abstract: Pipeline corrosion management is dependent on understanding the previous, current and future operational conditions of the pipeline. Understanding the operational conditions within the pipeline includes not only the measuring physical parameters of the fluids passing through the pipeline but also the chemical characteristics of the fluids, alongside assessment of the effectiveness of any chemical treatments deployed to protect the pipeline. This paper highlights a number of commonly seen fluid sampling and analytical mistakes which have resulted in a detrimental understanding of the fluids composition and treatment effectiveness, which in turn,  have resulted in excursion from the pipeline corrosion management plan and subsequent failures. This experience has come about by numerous field based surveys and audits of active oil and gas facilitates from water injection , through to fluids production and processing systems.