Bitumen diluents with very low basic sediment and water (<0.5%) are transported in Enbridge’s (the Company) pipelines. The dissolved water and oxygen in diluents have the potential to cause corrosion in the pipeline. In addition, low density and viscosity of the diluent facilitate solid settling, raising the risk of under deposit corrosion. These potential corrosion risks are mitigated by continuous application of a corrosion inhibitor and regular pipeline pigging to remove the solids. Previously, a modified NACE TM-0172 method was developed to identify a suitable corrosion inhibitor (NACE-2019-13028). A highly sensitive analytical method to measure the sub-ppm inhibitor residual was also developed as a key performance monitoring tool (NACE-2019-13112). In this study, we report the results from an ongoing continuous pipeline inhibitor program. Specifically, inhibitor residual was measured in diluent as well as solids collected at various locations from the cross-country pipeline. The corrosivity of the diluent was assessed by NACE TM-0172.

Subject
Water, Inhibitor performance, Extraction, Trends, Containment, Adsorption, Solids, Pipelines, Personnel, Metals, Corrosion inhibitors, Pigging, Samples
Keywords:
diluent pipeline, condensate pipeline, corrosion inhibitor, solid corrosion product, iron oxides, iron oxyhydroxide, goethite, corrosion inhibitor adsorption, corrosion inhibitor residual
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2020
Association for Materials Protection and Performance (AMPP)
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