Corrosion of carbon steel in two phase flow (CO2 gas-CaCO3 solution) controlled by sacrificial anode

Corrosion tests of carbon steel (CS) in two phase flow of gas-liquid (CO2 gas-CaCO3 solution) were carried out using electrochemical polarization technique. The effects of different operating parameters such as temperature, agitation speed, gas flow rate, and time were investigated. Flat blade disc turbine mixer was used to simulate the two phase flow conditions. Cathodic protection was used to protect carbon steel in the salt solution-CO2 mixture by using zinc as a sacrificial anode under different operating conditions. The corrosion rate (CR) represented by limiting current density (iL) in two phase mixture decreased with the increase in agitation speed depending on the flow rate of CO2, temperature, and time. In general, increasing the CO2 gas flow rate caused a clear decrease in the CR especially under agitation conditions. Increasing the temperature caused a considerable increase in the corrosion rate. Good corrosion protection percent was attained which reached up to 85%. In addition, the variations of corrosion potential with time for both metals (CS and Zn) were determined as well as the loss in weigh for each metal.