The detrimental effects of corrosion in transportation pipelines have been a primary issue for the oil and gas industry for many years. Every year, millions of dollars are invested into corrosion inhibitors in order to minimise corrosions implication on flow assurance. Imidazoline and its derivatives have been a prevalent corrosion inhibitor owing to its good adsorption characteristics and film forming capabilities; however, there remains some uncertainty in literature pertaining to the effect of temperature on its performance. GULP simulation software was used to study the effect of temperature on the thermodynamic properties of imidazoline in carbon steel pipelines. Entropy, heat capacity, Helmholtz free energy, entropy and Gibbs free energy were influenced by changes in temperature. An optimal operating range was found to exist between 298K and 333K. Within this range, spontaneous chemisorption was occurring and the imidazoline molecules possessed enough kinetic energy to displace any bound water on the metal surface to permit the preferential adsorption of the imidazoline head group. However, beyond 333K, the kinetic energy of the system hindered the steady formation of the protective barrier, reducing its inhibitive potential. This study agrees with previous literature on the effect of temperature on the ability of imidazoline as a corrosion inhibitor, however further studies into the effect of pipeline conditions and imidazoline molecular structure are needed in order to affirm the optimal applicability of imidazoline as a corrosion inhibitor.
Michael K Akindeju, Emmanuel O Obanijesu, Matthew Edwards Rebecca Boyanich and Harvinder Mohar