Skip to Main Content
 

Global Search Box

 
 
 

ETD Abstract Container

Abstract Header

Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer in CO2 Corrosion

Navabzadeh Esmaeely, Saba
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1367855650

Abstract Details

2013, Master of Science (MS), Ohio University, Chemical Engineering (Engineering and Technology).
Due to the isostructurality between calcite (CaCO3) and siderite (FeCO3), the Ca2+ ion incorporates in the hexagonal FeCO3 lattice and vice versa the Fe2+ ion incorporates in the hexagonal CaCO3 lattice. Thus, in aqueous CO2 environments, where both Ca2+ and Fe2+ are present, such as in gas reservoirs or deep saline aquifers, following CO2 injection, mixed metal carbonates with the formula FexCayCO3 (x+y=1) will be expected to form. This will likely have implications for corrosion, so that corrosion product layers will have the potential to be inhomogeneous, with behavior that deviates from that of pure FeCO3. In the present study, the effect of Ca2+ on the CO2 corrosion behavior of mild steel was investigated with different concentrations of Ca2+ (10, 100, 1,000 and 10,000 ppm). Electrochemical methods (open circuit potential (OCP) and linear polarization resistance (LPR) measurements) were used to measure the corrosion rate with time. Surface analysis techniques (scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD)), were used to characterize the morphology and composition of the corrosion products. The results showed that with low concentrations of Ca2+ (10 and 100 ppm), the corrosion rate decreased with time due to the formation of protective FeCO3 and/or FexCayCO3 (x + y =1). However, the presence of high concentrations of Ca2+ (1,000 and 10,000 ppm) resulted in the change of corrosion product from protective FeCO3 to non-protective CaCO3 and FexCayCO3 (x + y =1) and an increasing corrosion rate with time. While the general corrosion rate was high for both 1,000 and 10,000 ppm Ca2+, surface analysis data revealed that localized corrosion was observed in the presence of 10,000 ppm Ca2+. Since Ca2+ was added in the tested conditions as CaCl2, the possible effect of Cl- on the non-uniform attack was studied by testing with the equivalent concentration of Cl- using a NaCl solution. However, the result showed that Cl- had no effect on the non-uniform corrosion behavior. Although non-uniform corrosion behavior may be due to many factors, an increasing number of experimental results link the non-homogeneous corrosion product layer to non-uniform corrosion attack. The determination of the relative concentrations of Ca2+ and Fe2+ in FexCayCO3 is of key importance in understanding and predicting the relative properties and stabilities of such mixed metal carbonates. Using Bragg’s law and equations to relate interplanar spacings to unit cell parameters, X-ray diffraction (XRD) data can yield precise values for incorporation of Ca2+ in FexCayCO3 solid solutions. The results show that as the concentration of Ca2+ in the structure of this mixed metal carbonate increases the general corrosion rate increases. Non-uniform corrosion behavior was observed with 90% concentration of Ca2+ in the FexCayCO3 structure.
Srdjan Nesic, Prof. (Advisor)
124 p.
Engineering
CO2 corrosion; Calcium carbonate; Iron carbonate; CO2 capture and storage; Localized; Solid solution

Recommended Citations

Citations

  • Navabzadeh Esmaeely, S. (2013). Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer in CO2 Corrosion [Master's thesis, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1367855650

    APA Style (7th edition)

  • Navabzadeh Esmaeely, Saba. Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer in CO2 Corrosion. 2013. Ohio University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1367855650.

    MLA Style (8th edition)

  • Navabzadeh Esmaeely, Saba. "Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer in CO2 Corrosion." Master's thesis, Ohio University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1367855650

    Chicago Manual of Style (17th edition)

ohiou1367855650
1,363
© 2013, all rights reserved.
This open access ETD is published by Ohio University and OhioLINK.