Effect of transition rate and propargyl alcohol concentration on the corrosion of carbon steel during transitions in fluid composition from inhibited hydrochloric acid to sodium chloride brine. (1st April 2020)

• Record Type: Journal Article
• Authors: Barker, Richard; Pickles, Benjamin; Hughes, Trevor L.; Barmatov, Evgeny; Neville, Anne
• Is Part Of: Electrochimica acta. Volume 338(2020)
• Publication Date: 2020-04-01
• Subjects: Acidizing -- Carbon steel -- Acid corrosion -- Acid inhibition -- Propargyl alcohol; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2020.135877
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: A newly developed flow cell technique is used to determine the progressive corrosion rate behaviour of carbon steel during concomitant changes in HCl and propargyl alcohol inhibitor over time, analogous to that experienced during matrix acid flowback. The corrosion response was found to be largely independent of fluid transition rate. Increasing initial inhibitor concentration supressed the overall corrosion rate with two peaks in corrosion rate being observed during every dilution process; the first peak relates to a critical propargyl alcohol concentration and the second to a critical HCl molarity. Such behaviour is discussed in the context of polymeric film formation/inhibition mechanisms. Highlights: Transitions in fluid composition are achieved using a custom-built once-through flow cell apparatus. The flow cell is used to study the corrosion behaviour of low carbon steel exposed to unspent inhibited acid progressively diluted by a NaCl brine. Two peaks in the corrosion rate are observed during the dilution process. The first peak occurs when a critical inhibitor concentration is met, preventing inhibitor film healing. The second peak occurs when a critical acid molarity is reached, initiating inhibitor film degradation.