Inhibition of Under-Deposit Corrosion of Carbon Steel by Thiobenzamide

Abstract

The inhibition performance of thiobenzamide (TB) against the under-deposit corrosion of carbon steel in CO2-saturated, chloride-containing environment has been investigated. TB concentrations were varied from 10 – 200 ppm and temperatures from 30°C to 60°C were tested. TB effectively inhibits corrosion at carbon steel surfaces with and without sand deposits, reducing the general corrosion rates below 0.1 mm y−1 in all cases studied. Electrochemical test results suggest that inhibition occurs via adsorption at the steel surface through the S atom of the TB molecule. Potentiodynamic polarization measurements show that the inhibition mechanism differs at surfaces with and without sand deposits with temperature change over the range of 30°C to 60°C. Surface analysis of the corroded steels showed that general corrosion takes place at surfaces without sand deposits, whereas localized corrosion proceeds at the surfaces underneath a sand deposit, both in the presence and absence of thiobenzamide.

Microbiologically Influenced Corrosion of Carbon Steel Beneath a Deposit in CO2-Saturated Formation Water Containing Desulfotomaculum nigrificans

“…Furthermore, some local areas (e.g., electrode 5) had a much higher anodic current density, suggesting to localized corrosion, which was observed from the corrosion morphology in Figure 6. Localized corrosion is often found in UDC (Vera et al, 2012; Pandarinathan et al, 2013b). Han et al (2013) found that the pitting corrosion under sand coming from the galvanic effect.…”

A Novel Approach for the Evaluation of Under Deposit Corrosion in Marine Environments Using Combined Analysis by Electrochemical Impedance Spectroscopy and Electrochemical Noise

“…In the present case, the mechanism of UDC is believed to be analogous to regular crevice corrosion because of the oxygen differential aeration cell formed [32,58] i.e. beneath the areas covered with deposits, the anodic dissolution currents will be intense, whereas the cathodic currents (controlled mainly by the oxygen reduction reaction) will be concentrated typically around the deposited layer at microscopic uncovered areas [59]. As a result of this galvanic effect, UDC will be started, preferably at these crevices, in the form of localized crevice corrosion [4,21,60,61].…”

Experimental study on under-deposit corrosion and its inhibition using electrochemical methods and electronic coupon technique

“…Serious corrosion attacks have been found in the pipelines with large amounts of solid particles covering the pipeline internal surfaces. These kinds of corrosion behaviors are always defined as under-deposit corrosion (UDC) (Tan et al , 2011; Pandarinathan et al , 2013a, 2013b, 2013c). UDC is a tough problem for the pipelines in low flow rate conditions that silica sand or carbonate deposit may accumulate at the bottom of the pipe (Pandarinathan et al , 2013a, 2013b, 2013c).…”

“…These kinds of corrosion behaviors are always defined as under-deposit corrosion (UDC) (Tan et al , 2011; Pandarinathan et al , 2013a, 2013b, 2013c). UDC is a tough problem for the pipelines in low flow rate conditions that silica sand or carbonate deposit may accumulate at the bottom of the pipe (Pandarinathan et al , 2013a, 2013b, 2013c). The control of UDC is currently being accomplished through the methods such as pigging and the use of corrosion inhibitor chemicals.…”