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A Modified Thermodynamic Model for the Prediction of Mild Steel Corrosion Products at High Temperature in H2S Environment

Product Number: 51319-12869-SG

Author: Shujun Gao

Publication Date: 2019

$20.00

Predicting the corrosion products is of prime importance to understand the corrosion mechanisms and the protectiveness of the layer to the steel underneath. In an H2S environment however it is difficult to build a universal thermodynamic model (Pourbaix diagram) due to the polymorphous iron sulfide formation which is always kinetics related and time-dependent. What’s worse our recent high temperature studies show a thermodynamically less stable but kinetically favored inner Fe3O4 layer also comes into play and greatly affects the corrosion rate. In this work different partial pressures of H2S (pH2S=0.10~2.0 bar) and longer duration (21 days) experiments at high temperature were conducted to determine if Fe3O4 can eventually disappear as expected. The results show that Fe3O4 never disappeared but was always present as a “real” corrosion product layer. Therefore a modified thermodynamic model was proposed by reconsidering the Fe3O4 formation reaction and by keeping the Fe3O4 stability zone in Pourbaix diagram. The current model shows a better agreement with the experimental results.

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A Molecular Dynamics Approach to Understand Adsorption and Self-Assembly of Corrosion Inhibitors on Metal Surface

Product Number: 51319-12953-SG

Author: Himanshu Singh

Publication Date: 2019

$20.00

The use of organic corrosion inhibitors is an effective way of impeding internal corrosion of low alloy carbon steel pipelines in oil industries. Although being widely used the actual inhibition mechanism of these molecules is not clearly understood. In this work we have employed Molecular Dynamics simulations to understand the aggregation and adsorption behavior of organic corrosion inhibitors in aqueous medium. Near the metal-water interface different states of inhibitors such as micellar state adsorbed state Self-assembled monolayer state are in dynamic equilibrium with each other. The goal of this research is to determine free energy of each of these states.Using molecular simulations we have determined relative free energies of different states in which the inhibitor molecules may exist near metal water interfaces. Our free energy calculations show that micelles experience a long-range repulsion from the metal surface. There exists a free energy barrier for adsorption of micelles but no such barrier for un-aggregated inhibitors. In the SAM state presence of water molecules is noticed in between the inhibitors.

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A Multielectrode Array Sensor for Coating and Pretreatment Evaluation on Carbon Steels

Product Number: 51317--9011-SG

ISBN: 9011 2017 CP

Author: Yugo Ashida

Publication Date: 2017

$20.00

In this study a coupled multielectrode array sensor (CMAS) is used for coating and pretreatment evaluation on carbon steels. The preliminary testing results are summarized and discussed for further application.

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A new 13Cr OCTG for High Temperature and High Chloride Environment

Product Number: 89469-SG

Author: K. Tamaki

Publication Date: 1989

$20.00

Newly developed 13%Cr steels with 0.010-0.18%C, 4%Ni, and 1%Mo show excellent corrosion resistance in severe sweet environments, such as temperature of 300F (150C), 20%NaCi, and 560psi (3.85MPa) PCO2, which the conventional API 5CT 13%Cr (0.15-0.22%c) can not withstand.

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A New Approach to the Development of Cost Effective Combined Scale and Corrosion Inhibitors

Product Number: 51319-13318-SG

Author: Miriam Barber

Publication Date: 2019

$20.00

One of the recent challenges faced by the oil and gas industry includes the need to reduce operational costs by developing new cost effective combined scale and corrosion inhibitors with similar or improved performance compared to existing products in the market place.The formulation of combined scale and corrosion inhibitors is never an easy task since most scale and corrosion products are often incompatible and require complex formulations to ensure product stability and scale and corrosion inhibition performance. In addition most combined products are tested for individual scale or corrosion inhibition performance as either the individual products or the blend. In some cases compromise in corrosion testing may be made by modifying the brine chemistry to minimise the contributing effects of scaling on corrosion inhibition assessments. Although the above is a proven approach for product evaluations it does not often offer much flexibility in terms of product optimisation and cost reduction without significant test work.A new approach based upon compatibility screening and using a new test methodology for the simultaneous measurement of both scale and corrosion inhibition has been utilised to develop a new scale and corrosion inhibitor for both topside and sub-sea application.This process also takes into consideration cost and efficiency factors to provide efficient protection against scale and corrosion. In addition information is also provided on the kinetic processes of simultaneous scale and corrosion inhibition on a surface. Complimentary information on the analysis of the scale deposits have also been obtained using Scanning Electron Microscopy Energy Dispersive X Ray Analysis (SEM/EDAX) and X Ray Diffraction (XRD).The results obtained in this study showed that this new approach could be used for the quick and effective design of cost effective efficient combined scale and corrosion products while also providing a better understanding of the mechanisms of simultaneous scale and corrosion.Key words: Combined scale and corrosion inhibitors cost-effective SEM/XRD kinetics

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A New High Performance Biguanide Polyammonium-Based Blend For Control Of Microbiological Fouling In Oil And Gas Stimulation

Product Number: 51321-16556-SG

Author: Christy C. Wentworth, Ph.D./ Jeffrey F. Kramer, Ph.D.

Publication Date: 2021

$20.00

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Product Number: 51320-14435-SG

Author: Zhu Jin-yang, Jin Ying, Wen Lei, Xue Yan-peng, Honda Hiroshi

Publication Date: 2020

$20.00

The control of multiphase flow corrosion in oil and gas industry is one of the biggest challenging tasks. Since the 1990s, several organizations have established and operated large-scale flow loops to simulate and reproduce the field service environment of oil and gas pipelines. Based on comparison and investigation of the above loops, a new and advanced system, including several four inches internal diameter loops for studying corrosion under multiphase flows, was successfully built by us. By using this system, multiphase flows with various combinations of gas, water, oil and sand can be realized at the highest temperature of 140 oC and the highest pressure of 10 Mpa. Moreover, some loops in this system can adjust pipeline at different angels from 0 to 90°, which allow horizontal/vertical/sloping conditions to be simulated in laboratory. Many advanced measuring and monitoring technologies, such as Particle Imaging Velocimetry (PIV), high speed video camera and LPR/ER probe, are employed for simultaneously recording flow events and corrosion rates. An inhouse plane three-electrode probe is employed for conducting in situ electrochemical measurements. Such technologies would allow deep researching of corrosion behaviors and mechanisms in multiphase flow environments. Moreover, a new software based on Fluent and the existing multiphase corrosion models was developed to realize the numerical simulation of multiphase flow in loop.

NACE Conference Papers

Association for Materials Protection and Performance