Development of Multifunctional Coatings for Protection against Erosion and Corrosion in Qatar Oil and Gas Production
Open Access
- Author:
- Dizvay, Isin
- Graduate Program:
- Engineering Science and Mechanics
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- July 08, 2014
- Committee Members:
- Barbara Shaw, Thesis Advisor/Co-Advisor
Elzbieta Sikora, Thesis Advisor/Co-Advisor - Keywords:
- Pipeline Corrosion
Oil Gas Pipelines
Erosion
Corrosion - Abstract:
- This thesis investigates some of the possible components of a multifunctional coating system to peotect against erosion and corrosion for the pipelines in Qatar oil and gas production. The coating system is divided in two parts according to the functions; the sacrificial and the barrier layer. The candidates were evaluated separately against only corrosion. Erosion studies are part of the overall program, but not part of this thesis. Zn, Al 1100 and Galvalume were chosen as the constituents of the sacrificial layer. A group of panels coated with organic coating were donated by NOV Tuboscope and were tested as the barrier layer. Also, three steel substrates (bare, burned-off and white-metal finish) were tested to observe the substrate behavior. The Zn, Al 1100, Galvalume coated steel samples, and the steel panels were tested for a week under constant immersion, while the coated panels were tested for 14-18 weeks under constant immersion. The testing and constant immersion environments simulated to the temperature, chloride concentration, and pH of the environment in the oil and gas pipelines in Qatar. The solution used in these two environments was a-2000 ppm Cl- containing CO2 saturated NaCl-HCl mixture at a pH of 3.5 and at 60oC. To investigate the corrosion behavior of the Zn, Al 1100, Galvalume, Open Circuit Potential, Polarization Resistance measurements and Electrochemical Impedance Spectroscopy scans were conducted. Polarization Resistance was not conducted for the coated panels. The data obtained from Open Circuit Potential and Polarization Resistance experiments were analyzed via Echem Analyst (from Gamry Software) and the data obtained from Electrochemical Impedance Spectroscopy was analyzed via Zview (version 3.2b) by fitting the data to electric circuit models. Even though the corrosion behavior of Zn, Al 1100 and Galvalume was similar, the corrosion rate of the samples showed that Al 1100 samples lasted longer. Therefore, they are more promising for as candidates for the sacrifical layer. As expected, substrated steel presented very low corrosion resistance for the entire time of testing. Almost all of the organic coatings showed no deterioration visually, though some of the coatings exhibited lower coating resistance values than their initial value. The parameters affecting the coating resistance and the coating capacitance are the filler amount, the coating thickness, and the coating type. In addition, one of the coatings on the panels was subjected to the scratch study. A handmade artifact was made on the coating to observe the healing properties of the coating after a defect was observed on the surface.