Fabrication of thermally sprayed coating systems for mitigation of ice accumulation in carbon steel pipes and prevention of pipe bursting

Abstract

Various multi-layered thermally sprayed coatings were developed as heating systems for de-icing of the carbon steel pipes. Feasibility of fabrication of resistive heating coatings, namely Ni20Cr and Ni50Cr deposited by flame spraying, air plasma spraying, and high-velocity oxygen fuel spraying processes, onto the carbon steel samples were studied. Given the electrical conductivity of carbon steel, alumina was deposited by flame spraying or suspension plasma spraying processes between the conductive resistive heating coating and the substrate to prevent short circuiting and flow of electrons between these layers. Performance of the developed coating systems was investigated by conducting heating tests in a cold room under different environmental conditions. It was found that the proposed heating system was able to generate the heat that was required to prevent formation and accumulation of ice, thus avoiding the detrimental effects such as bulging and ultimate bursting on the pipe of internal pressurization. Furthermore, it was also found that the selection of the thermal spraying process and spraying parameters can have a noticeable impact on the electrical performance. The obtained promising results indicate the potential utilization of these coatings in industry on mass scale.