There are several types of CO2 absorption processes. Particularly in the process with hot potassium carbonate solution, corrosion inhibitor is added to prevent corrosion of carbon steel process equipment.
However, in some cases, the inhibitor may not work beneficially because of the improper process condition. In this study, the effect of gas-liquid flow and inhibitor concentration on corrosion of carbon steel was evaluated by laboratory experiment. The result of this experiment implied that corrosion had occurred at the area of the specimen where the solution was not enough provided. This corrosion occurred even if there was enough amount of inhibitor in the solution. In addition, the black scale consisting of ferrous carbonate on the surface of specimen has locally removed in the gas-rich and liquid-lean condition. These results accord with the cause of damage observed on actual commercial plant. This study revealed the significance of considering gas-liquid flow dimension when designing a CO2 absorption process with hot potassium carbonate solution.
Key words: CO2 absorption process, hot potassium carbonate corrosion, carbon steel, inhibitor, gas-liquid flow