Grey Correlation Analysis of Corrosion on the First Oil Atmospheric Distillation Equipment

Corrosion is serious on the first atmospheric distillation unit when the plant processes high-acid crude oil from Shengli oil field. Measured the corrosion pate on the top of atmospheric distillation tower with electric resistance probe every two month, monitored sulfur value, salt value, salt value after desalt, acid value in crude oil, iron ion in product container and pH value in cooling water every month. Created grey data sequence with equal weight whitenization and stepwise ratio generation method, carried on grey correlation analysis, calculated absolute, relative and synthetic degree of incidence, carried on predominance analysis too. The conclusion is that the main factor to corrosion is acid value, and then is salt value after desalt, pH value, content of salt, sulphur value and iron ion value. Getting rid of salt from crude oil as possible is benefit to equipment, and monitoring salt value after desalts, pH value could predict corrosion.