The current energy production processes go hand in hand with corrosive phenomena; which is the case of combustion process in a refinery, where the presence of compounds such as CO2 and H2O, result in alloys catastrophic carburization and oxidation respectively. In this research work was evaluated the corrosive effect that can be generated in a real combustion environment, for which, it was necessary to select a model mixture of refinery gases and to simulate its theoretical combustions products. The main results showed the formation of a semi-protective duplex oxide layer; whose inner layer was composed mainly of chromium, while the outer layer was much richer in iron. On the other hand, the carburizing effect of CO2 was suppressed by the high oxygen potential in the combustion environment; leading to the conclusion that in real conditions, at 750 °C and after 200 h of testing, steels such as ferritic alloy ASTM A335 P91, could not present appreciable damages during their operation in refinery boilers and furnaces.