Corrosion of carbon steel in CO{sub 2} saturated aqueous solutions containing small amounts of H{sub 2}S

Book · Sat Dec 31 04:00:00 EST 1994

OSTI ID:70025

Videm, K; Kvarekvaal, J ^[1]

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1. Univ. of Oslo (Norway)

Carbon steel specimens have been exposed in CO{sub 2} containing brine with different amounts of H{sub 2}S at 70 and 80 C. Addition of 0.02 mMol/l sulphide, corresponding to 45 Pa H{sub 2}S partial pressure, to brine with 70 kPa f kPa CO{sub 2} at pH 4.2 caused a rapid formation of a protective corrosion film. After about 15 minutes the anodic dissolution rate at a given potential was reduced two decades. The rate of the cathodic reactions was only slightly reduced. These changes in the electrochemical kinetics increased the corrosion potential to a region where localized breakdown of the protective film and pitting corrosion could take place. After a day`s exposure, H{sub 2}S partial pressures in the range 14 Pa to 56 Pa led to corrosion rates varying unsystematically between 0.2 mm/year to 3 mm/year. A pronounced decrease of the corrosion rate was frequently observed for low H{sub 2}S contents. An H{sub 2}S partial pressure of 56 Pa resulted consistently in an increase of the corrosion rate. For H{sub 2}S partial pressures between 15 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) where {Delta}pH is the increase in pH caused by NaHCO{sub 3} addition.

• OSTI ID: 70025
• Report Number(s): CONF-940222--
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
36 MATERIALS SCIENCE
BRINES
CARBON DIOXIDE
CARBON STEELS
CATALYTIC EFFECTS
CHEMICAL COMPOSITION
CORROSION
CORROSION PRODUCTS
CORROSIVE EFFECTS
EXPERIMENTAL DATA
FIELD PRODUCTION EQUIPMENT
HYDROGEN SULFIDES
IRON CARBONATES
IRON SULFIDES
KINETIC EQUATIONS
PASSIVATION
PH VALUE
PRESSURE DEPENDENCE