Application of solar photovoltaic electricity in unravelling the effects of coating defects on cathodic protection parameters of buried pipeline

Abstract

Abstract Corrosion management in some remote locations such as Niger Delta region of Nigeria, is at risk of uncertainty of constant power supply. Thus, solar photovoltaic (PV) presents a sustainable alternative to conventional fossil energy in mitigating pipeline failure, associated human and material harzards and other environmental exposures. Coating defects takes place when the surface of the structure is cathodically exposed. An epoxy coating was applied on the X65 carbon pipeline powered with four (4) solar PV modules to charge a 200Ah battery to generate a direct current (DC) and to detect defects initiated on the coated pipe. Linear Polarization Resistance (LPR) technique was adopted in assessing cathodic protection (CP) parameters of the coated pipe. The result shows that current flow decreased with an increase in the size of the defect. Resistance to CP was found to be 12354263.07 Ohm.cm2 compared with no CP of 87174 Ohm.cm2 at 0.1 cm2 scratch size. By implication, the application of coating with CP in the absence of defects was observed to significantly increase cathodic current. This is otherwise known as overprotection, a situation that enhances hydrogen embrittlement and coating disbondment.