Abstract

The research paper focuses on oil pipe lines used in desert region of Oman that is exposed to very high ambient temperature affects the coating properties resulted in brittleness in coatings. The impact of high ambient temperature is analyzed through heat transfer rate and thermal stress. Two coatings are considered, commercially available fusion bonded epoxy (FBE) coating and experimentally developed electroless nickel phosphorous (EN-P) composite alloy coating. Simulation is done under three ambient conditions, morning at 308K, mid-day at 328K and evening when temperature was around 313K along with crude oil temperature of 343K. Thermal analysis demonstrates that at high ambient temperature EN-P composite alloy coating has low heat transfer rate as compared to FBE coating and its thermal efficiency was around 96% against uncoated pipe and around 69.4% less as compared to FBE coating. The lower the heat flow, the more effective the insulation and it improves the stability of the coating. On the other hand, as the heat flow increases, the insulation is more pronounce to thermal expansion due to high thermal stress behavior. In this scenario, EN-P composite alloy coating is more sensitive as compare to FBE coatings and thus it becomes more pronounce towards stress corrosion cracking (SSC). The impact of thermal stress has significant effect on structural strength and stability, potentially causing cracks or breaks within certain components. Such failures compromise the overall design of the structure, which can lead to possible weakening and deformation at high ambient temperature.

Keywords: High ambient temperature; Thermal analysis; FBE coating; EN-P composite alloy coating; Thermal stress; Heat transfer rate; Stress corrosion cracking