The Corrosion Of Mild Steel In Dioxide Carbon Enviroment And Two Phases' Corrosion Inhibitor

Because of the two phase corrosion in mining and transiting process in Daqing deep-seated natural gas field, we study it and one corrosion inhibitor for it had gotten.Firstly, we studied the effect of some factors on carbon steel in the CO₂ corrosion system. The research shows, the max velocity in gas present at a higher temperature then in liquid. The corrosion velocity goes up more in liquid than in gas along with the pressure of CO₂ going up. If we increase the concentration of Cl^-, the corrosion velocity go down slowly in gas but it go up quickly in liquid. The velocity of flow had an obvious effect on the corrosion and the corrosion velocity went up more in liquid than in gas when the velocity went up. As the time went, the corrosion velocity go down slowly. Fe²⁺ has a good effect on in inhibiting the corrosion.We synthesized a series of imidazoline derivants by using organic acids and amine after the designation of the imidazoline molecule, which is analyzed by infrared spectrum. Then we studied the effect of temperature, concentration and molecule structure on the efficiency of the imidazoline dericant inhibitors by the method of weight losing. It showed, the inhibiting efficiency had a max value along with the increasing of concentration. The changing of temperature has no effect on the corrosion velocity in the CO₂ system with the imidazoline dericant inhibitors.The molecule structure have obvious effect on its inhibiting efficiency, phenyl, alkene double bond and alkyl are helpful for inhibiting efficiency.We blend some inhibitors to get an inhibitor which has better efficiency based the characteristic of two phase corrosion. The two phase corrosion inhibitor MLV-1 had been gotten and the mechanism of the inhibiting was studied by potentiodynamic polarization curve and intercourse impedance. The research shows that MLV-1 is more efficient than single component and it is a double-pole inhibitor.