This paper provides an overview of various properties influencing efficacy of corrosion inhibitors including transportability, efficiency, availability, and secondary inhibitor properties (TEAS); highlights various standards available to evaluate these properties; describes status of implementation of these standards; emphasizes the importance of developing standard test methods; identifies the gaps in evaluating inhibitor efficacy; and elaborates an industry effort underway to fill the gaps and to develop standard test methods on corrosion inhibitor evaluation and monitoring.
Time-tested and proven methods to control corrosion of oil and gas industry infrastructures (pipelines, facilities, and refineries) include the use of appropriate materials, protective coatings, cathodic protection (CP), and corrosion inhibitors.
Criteria for evaluation, qualification, and selection of materials, coatings and application of CP are quantitative and are typically followed rigorously (Table 1). Standards on these quantitative criteria are established, and in many cases have been adopted by regulatory authorities. However, such stringent requirements are not in place for the evaluation and application of corrosion inhibitors to control internal corrosion.
In comparison to the prescriptive and quantitative evaluation of pipe materials, coatings, and cathodic protection application – there are no similar standardized benchmarks to determine when corrosion inhibitors are required or how well (quantitatively) corrosion inhibitors should perform. Owing to an absence of consensus standards, many companies use in-house methods for evaluating or monitoring inhibitor performance.
While there is generalized agreement that true consensus standards would be beneficial, there has been little coordinated effort by industry to advance technology in this area. General obstacles to development of true consensus standards on corrosion inhibitors include:
• Lack of agreement on what parameters to test/monitor.
• Many companies align their test conditions to match their process conditions (which are individual and likely can't be agreed upon).
• Cost/effort avoidance.
The rest of this paper provides an overview of various properties influencing efficacy of corrosion inhibitors including transportability, efficiency, availability, and secondary inhibitor properties (TEAS); highlights various standards available to evaluate these properties; describes status of implementation of these standards; emphasizes the importance of developing standard test methods; identifies the gaps in evaluating inhibitor efficacy; and elaborates an industry effort underway to fill the gaps and to develop standard test methods on corrosion inhibitor evaluation and monitoring.
