Corrosion of carbon steel in carbon dioxide-saturated solutions containing small amounts of hydrogen sulfide

Journal Article · Sat Apr 01 04:00:00 EST 1995 · Corrosion

DOI:https://doi.org/10.5006/1.3293591· OSTI ID:46067

Videm, K; Kvarekvaal, J ^[1]

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1. Univ. of Oslo (Norway). Centre for Materials Research

Carbon steel specimens were exposed in carbon dioxide (CO{sub 2})-containing brine with different amounts of hydrogen sulfide (H{sub 2}S) at 70 C and 80 C. The addition of 0.02 mmol/L sulfide, corresponding to 45 Pa H{sub 2}S partial pressure (P{sub H{sub 2}S}), to brine with 70 kPa CO{sub 2} at pH 4.2 caused rapid formation of a protective corrosion film. After {approximately} 15 min, the anodic dissolution rate at a given potential was reduced two decades. The rate of the cathodic reactions was reduced only slightly. These changes in the electrochemical kinetics increased the corrosion potential to a region where localized breakdown of the protective film and pitting corrosion could occur. After a day`s exposure, P{sub H{sub 2}S} values in the range 14 Pa to 56 Pa led to corrosion rates varying unsystematically between 0.2 mm/y and 3 mm/y. A pronounced decrease in the corrosion rate was observed frequently for low H{sub 2}S contents. A P{sub H{sub 2}S} value of 56 Pa consistently resulted in an increase in the corrosion rate. For P{sub H{sub 2}S} values between 15 Pa and 60 Pa and a co{sub 2} partial pressure of 56 kPa, the following relationship between corrosion rate and pH was observed: corrosion rate (mm/y) = 1.25 (1 {minus} 0.34 {times} {Delta}pH).

• Sponsoring Organization: USDOE
• OSTI ID: 46067
• Journal Information: Corrosion, Journal Name: Corrosion Journal Issue: 4 Vol. 51; ISSN 0010-9312; ISSN CORRAK
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
36 MATERIALS SCIENCE
BRINES
CARBON DIOXIDE
CARBON STEELS
CONCENTRATION RATIO
CORROSION
CORROSION PRODUCTS
CORROSIVE EFFECTS
ELECTROCHEMICAL CORROSION
EQUATIONS
FIELD PRODUCTION EQUIPMENT
HYDROGEN SULFIDES
OIL WELLS
PROTECTIVE COATINGS