Coatings and Chemical Inhibitors for Aged Pipelines in the Canadian Oil Patch

                                                                                                                  ABSTRACT

In the Canadian oil patch the corrosion of aged pipeline internals is economically challenging and has resulted in costly unplanned shut-downs.  While chemical inhibitors have been deployed as one of the primary means to protect aged and uncoated pipeline infrastructure, some aged pipelines have proved difficult to treat with chemical inhibitors.

This paper describes an alternative corrosion mitigation program. Certain high performance epoxy linings with various chemical resistance and cross-link density profiles were tested for immersion in judiciously selected corrosion inhibitors.  The aim was to further enhance the knowledge base of chemical resistance of linings already used for in-situ coating applications in aged and badly corroded pipelines.

Various aspects of the epoxy lining composition and the chemical inhibitors are examined and the basic chemistry is reviewed. An outline of the specific chemical resistance testing is discussed as well as the use of Electrochemical Impedance Spectroscopy (EIS) to assess the influence of chemical inhibitors on the barrier performance of the epoxy linings.

Keywords:  aged infrastructure, coating selection, corrosion inhibitors, laboratory testing, epoxy linings for pipes, Electrochemical Impedance Spectroscopy