Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer inCO2 Corrosion

Bibliographic Details
Main Author:	Navabzadeh Esmaeely, Saba
Language:	English
Published:	Ohio University / OhioLINK 2013
Subjects:	Engineering CO2 corrosion Calcium carbonate Iron carbonate CO2 capture and storage Localized Solid solution
Online Access:	http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1367855650

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spelling	ndltd-OhioLink-oai-etd.ohiolink.edu-ohiou13678556502021-08-03T05:23:05Z Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer inCO2 Corrosion Navabzadeh Esmaeely, Saba Engineering CO2 corrosion Calcium carbonate Iron carbonate CO2 capture and storage Localized Solid solution 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. 2013-09-25 English text Ohio University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1367855650 http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1367855650 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection	NDLTD
language	English
sources	NDLTD
topic	Engineering CO2 corrosion Calcium carbonate Iron carbonate CO2 capture and storage Localized Solid solution
spellingShingle	Engineering CO2 corrosion Calcium carbonate Iron carbonate CO2 capture and storage Localized Solid solution Navabzadeh Esmaeely, Saba Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer inCO2 Corrosion
author	Navabzadeh Esmaeely, Saba
author_facet	Navabzadeh Esmaeely, Saba
author_sort	Navabzadeh Esmaeely, Saba
title	Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer inCO2 Corrosion
title_short	Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer inCO2 Corrosion
title_full	Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer inCO2 Corrosion
title_fullStr	Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer inCO2 Corrosion
title_full_unstemmed	Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer inCO2 Corrosion
title_sort	effect of calcium on the formation and protectiveness of the iron carbonate layer inco2 corrosion
publisher	Ohio University / OhioLINK
publishDate	2013
url	http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1367855650
work_keys_str_mv	AT navabzadehesmaeelysaba effectofcalciumontheformationandprotectivenessoftheironcarbonatelayerinco2corrosion
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Effect of Calcium on the Formation and Protectiveness of the Iron Carbonate Layer inCO2 Corrosion

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