NACE East Asia & Pacific Area Conference

UpStream & Top of Line Session
 
17 August, Wednesday - Kedah Room - 10:45am - 12:30pm

Chair : Dr. Lee Chee Hong, Synergy Oil & Gas Engineering

Top of the Line Corrosion in CO2/H2S Environments

17 August, Wednesday - Kedah Room - 10:50am - 11:20am

Bio of Speaker

Abstract

Full Name :   Dr. Najmiddin Yaakob
​​Title / Position:  Professor
Company name :  Universiti Teknologi MARA
​  
Dr Najmiddin Yaakob
1) Currently is the  Deputy Dean (Students Affairs), Faculty of Chemical Engineering, Universiti Teknologi MARA. Shah Alam
2) Graduated in Bachelor of Chemical Engineering from UTM, MSc Chemical Engineering from UiTM and Ph.D from the Institute for Corrosion and Multiphase Technology, Ohio University, USA..
3) Research experiences:
  • Top of the Line Corrosion in Sweet and Sour Environment
  • Sour Corrosion mechanism
  • Elemental Sulfur Corrosion in Sour Glycolic Environment
  • Elemental sulfur corrosion mitigation by using sulfur solvent and inhibitor 
  • Corrosion Inhibitor, Coating from palm oil based
  
Top of the line (TLC) corrosion in sour (H2S) environments has not been well understood until now, since most reported TLC research has focused on sweet (CO2) conditions, with various models developed to predict corrosion rates and related phenomena in sweet systems. This has led to many unanswered questions relating to TLC mechanisms in CO2/H2S environments. Experiments were conducted in custom designed autoclaves and glass cell. Weight loss method for corrosion rate measurement, corrosion product analysis by SEM/EDX, optical profilometry, and condensed water analysis were used to investigate the TLC mechanisms. In marginally sour TLC between 0.015 mbar (15 ppm) to 0.03 mbar (30 ppm H2S), a non-homogenous FeS layer formed on the steel surface in shorter experiments (lasting a few days), with some areas being covered and others not. This localized corrosion which was not sustained, since pits were not seen in longer experiments lasting 28 days. Increases in H2S concentration between 0.08 mbar (80 ppm) to 0.15 mbar (150 ppm) did not lead to initiation of localized corrosion. The steel surface was uniformly covered by an FeS layer due to the greater scaling tendency that overcame the undermining by corrosion. Low general corrosion rate were found. Increase in water condensation rate lead to higher TLC rate due to saturation limits with respect to aqueous species required for formation of both FeCO3 and FeS, phases that can confer a degree of protection against corrosion. In highly sour TLC, (more than 10 mbar/10000 ppm H2S), the main parameter which controls TLC behavior is the characteristics of the FeS layer formed on the steel surface.  The formation of more coherent FeS layers was observed at higher steel temperature and conferred greater protectiveness regardless of the water condensation rate which is the main controlling factor in sweet TLC. Water condensation rate acts as a secondary effect that lowers the steel temperature.

Experimental Research on Top of Line Corrosion of Offshore Pipeline under Sweet and Sour Conditions

17 August, Wednesday - Kedah Room - 11:25am - 11:55am

Bio of Speaker

Abstract

Name:  Lei Zhang
Title / Position:  Professor
Company:  University of Science and Technology Beijing(USTB)
​​
​Lei Zhang, Associate Professor of University of Science and Technology Beijing(USTB), Vice Director of Material Failure and Control Research Institution of New Material Technology Research Institute (USTB), Secretary of Environment Sensitive Fracture Committee of Chinese Society of Corrosion and Protection, Faculty Advisor of NACE China Student Section. His major researches focus on high temperature high pressure H2S-CO2 corrosion in oil & gas field, hydrogen embrittlement and stress corrosion cracking, stainless steel and anticorrosive alloy material selection, pipeline and structure failure analysis, pipeline corrosion integrity management, pipeline ICDA, etc.
For the long distance offshore wet gas transportation, Top-of-Line corrosion has become one of the most important risk of pipeline integrity, which need more research on the mechanism and corrosion control technology. Top-of-line corrosion behaviour of pipeline steel under CO2 and/or H2S conditions has been studied using different methods, such as high temperature and high pressure autoclave with condensation function and corrosion loops. A series of experiments were carried out for different test duration up to 30 days. The influence of temperatures of wet gas, the condensate rate, the flow rate, water cut and the CO2 partial pressure were investigated. The corrosion rate was measured by weight loss and electrochemical method. The development of localized corrosion was studied and the mechanism in TLC environment was discussed. The test of corrosion inhibitor using in offshore wet gas pipeline were tested and discussed. Hydrogen permeation behaviour of pipeline steel under different sour condensate film condition was also investigated by in-situ testing. The effects of H2S corrosion product scales and the temperature of wet gas containing a high content of H2S on the hydrogen permeation of pipeline steel were studied by electrochemical methods.  ​

The Effect of Flow and O2 Impurities in High Pressure CO2 on the Corrosion Rate of UNSG10180 Steel

17 August, Wednesday - Kedah Room - 12:00pm - 12:30pm

Bio of Speaker

Abstract

Name:　Nor Roslina Rosli
Title / Position:  Senior Lecturer
Company:  UiTM
​  
Nor Roslina Rosli graduated with a B.Eng (Hons) Chemical Engineering from Universiti Teknologi Malaysia in the year 2002. After a brief working experience as a Environmental Process Engineer at an engineering consulting firm, she decided to move into the academic career. She was awarded a scholarship to pursue her studies at Universiti Kebangsaan Malaysia, and graduated with a M.Sc in Chemical and Process Engineering.  She then accepted a job as a Lecturer at Universiti Teknologi MARA, Shah Alam in 2005 at the Faculty of Chemical Engineering. Having various different field of research interest, including natural product extraction and supercritical fluid technology, her latest passion is corrosion science and coating technology. Her investigation on sweet corrosion of steel under CO2-EOR conditions has earned her a PhD in Chemical Engineering from Ohio University (USA) in 2015. She is currently a Senior Lecturer and the Head of Studies Center for the Oil and Gas Engineering Department in UiTM Shah Alam.
Corrosion studies in downhole conditions, particularly at CO2-EOR fields, involve high CO2 content with traces of impurities. CO2 that is anthropogenically-sourced from power plants may contain significant levels of impurities, such as oxygen (O2), that pose a higher risk of corrosion to injection/production wells and related infrastructure. Furthermore, CO2 injection in a water-alternating-gas (WAG) scheme provides a perfect environment for CO2 corrosion to occur on the well casing and tubing. The objective of this work is to determine the effect of flow on corrosion of steel in supercritical CO2 with the presence of O2 as an impurity. The concentration of the impurity corresponds to the amount of O2 that can be present in CO2 from an oxyfuel combustion flue gas. The corrosion activities of mild steel (UNS G10180) in CO2-saturated brine (1 wt% NaCl) was investigated using a 4-liter stainless steel autoclave for 48 hours in both static and flow systems. Experiments were conducted at 80°C and 9 MPa CO2 partial pressures, which is at supercritical CO2 condition. Results showed that the formation of a protective layer on the steel surface was disrupted by the increased mass transport of species to/away from the steel surface. Flow causes removal of loose iron oxide precipitate and interrupts the deposition of insoluble ferric precipitate. Therefore, the presence of flow amplified the severity of corrosion.