| In order to control the CO2 corrosion in the process of exploiting and transporting natural gas from deep natural gas field in Daqing, the composite corrosion inhibitors were studied in static and the dynamic states in this paper.According to the theory of composite and relation between structure and properties, ATMP, MOR, Tu and Ur were chosen as the inhibitors. P-tol was also added to the mixture since it could volatilze with vapor and enhance air pressure. Orthogonal method was adopted to optimize the inhibiton effect of the combination in 1000mg/L Cl-solution at 90℃. The optimal combination, which was defined as GT-2, was made up of ATMP 50mg/L, MOR 120mg/L, Tu 300mg/L, Ur 1400mg/L, OP-10 300mg/L and P-tol 300mg/L. The results of weight-loss indicated that GT-2 could effectively prevent SS41steel from corrosion, and its inhibition efficiency could reach 84.96%. The electrochemical tests also manifested that in 1000mg/L Cl- solution with GT-2, the corrosion of SS41steel potential moved to positive, and its polarization current was reduced. The polarization curves showed that the anodic and cathode process of SS41 steel in the solution containing GT-2 were both retarded in dynamic state. Composite corrosion inhibitor GT-2 can form layers under static potential of -0.1V.Surface analysis (by SEM) indicated that the SS41 steel corroded heavily in the blank, while there is little corrosion with GT-2 because of a compact film. FTIR analysis verified that complex film was formed on the surface of steel.
|
PDF Full Text Request