Influence of Cuban crude oil on the corrosion of AISI 1020 tubes in the Rente economizer

Abstract

In Cuba, electricity generation relies primarily on thermoelectric plants that operate using domestic crude oil with high sulfur (up to 8%) and vanadium (up to 150 ppm) content, which accelerates the corrosion of critical components. This study analyzes the influence of the chemical composition of three fuels (PCMN-1100 without additive and with CT 537 additive, and MAZUT 20) on the service life of the AISI 1020 steel pipes in the economizer of Unit 6 at the Renté thermoelectric plant. A modified Arrhenius kinetic model, sensitive to sulfur and vanadium, was applied and validated using in-situ ultrasound. The results show that PCMN-1100 crude oil without additive exhibits a corrosion rate of 0.23 mm/year and an estimated service life of 6 years, compared to 20 years for MAZUT 20 (CR = 0.054 mm/year). The addition of CT 537 reduces the critical thickness (CR) to 0.065 mm/year and extends the service life to 16 years, with a degradation curve virtually identical to that of MAZUT-20, demonstrating that the additive achieves performance comparable to that of imported fuel. A critical thickness of 2.4 mm is established as the safety limit, based on mechanical resistance criteria to internal pressure. Experimental validation with ultrasound shows an average deviation of 8% from the model, supporting its predictive applicability. It is concluded that fuel selection and the use of neutralizing additives are key strategies for tripling pipe durability and reducing unscheduled shutdowns, and that the CT 537 additive constitutes a viable alternative to imported fuel, with the advantage of utilizing a domestic resource.