Effects of Temperature and Pressure on Corrosion Products in a Steam-Flue Gas Envirorment: A Simulation Study

Abstract

Steam and flue gas injection is an enhanced recovery technique that has generated great interest in studies as it takes advantage of the gases produced in combustion processes, which increase the efficiency of crude oil recovery in the reservoir and diminish the emission of greenhouse gases. The operating conditions together with the injected fluids can result in a highly corrosive environment, degrading the properties of the materials used, in addition to operational and financial risks. This research focused on the study of API N-80 carbon steel exposed to a steam and flue gas atmosphere, at pressure and temperature conditions in the ranges of 800-1,100 psi (55.1-75.8 bar) and 520-560 °F (270.1-290.3 °C), in order to understand the synergy between pressure and temperature and the effect of each variable in the corrosion process. From the conditions described above, a simulation stage in HSC Chemistry software was developed to determine three factors: the theoretical corrosion products, the way they interact with each other, and the effect of further variables. Findings revealed that temperature at a constant pressure generated a decrease in the amounts formed of Fe2O3, this percentage decrease was of the order of 1 %, and FeCO3, where the percentage decrease was of the order of 0.23 %, and a greater formation of Fe3O4, this percentage increase was around from 18 to 19%. When evaluating the increase in pressure at a constant temperature, a greater amount of Fe2O3 and FeCO3 and a reduction of Fe3O4 were observed. The temperature variable had a greater effect than the pressure on the variation of the quantities formed in the thermodynamic equilibrium of the theoretical corrosion products.