Fe²⁺ Measurement and the Disadvantages of its Application in Study of CO₂ Corrosion

The procedure of Fe²⁺ measurement using spectrophotometer is described. The method is compared with the traditional weight loss in predicting CO₂ corrosion rate of carbon steel under the conditions of high temperature and high pressure. The results have shown that contrast to the weight loss, the corrosion rate obtained by measuring Fe²⁺ concentration is significantly lower. Moreover, this departure enlarges with the increase of mean corrosion rate. A thorogh investigation has determined that the most important reason for such deviation comes from the characteristics of CO₂ corrosion itself.