Corrosion Inhibition Of Water-soluble Polianiline For Mild Steel In Oilfield Water Injection

Polyacrylic acid doped polyaniline(PANI-?) is synthesized using aniline and ammonium persulfate by chemical oxidation method and carboxymethyl celluloseis doped polyaniline(PANI-?) is prepared by direct mixing. The results of FTIR, UV absorption spectra and X-ray diffraction analysis were identified to the products. The corrosion rates of PANI-?as a steel corrosion inhibitor in 0.5mol·L-1 hydrochloric acid and PANI-?in oilfield water injection were measured by the weight loss method, polarization techniques and electrochemical impedance spectroscopy(EIS) which used to study the film formation and destruction and the corrosion protection mechanism of those corrosion inhibitor PANI-?and PANI-?. A reference for the application of polyaniline corrosion inhibition in acidification oil and gas field is provided.PANI-?performed just averagely as a corrosion inhibitor for mild steel in 0.5mol·L-1hydrochloric acid media and its best efficiency attained 73.6%. Along with the added concentration of PANI-?increasing, the inhibition efficiency decreases instead. PANI-?is one kind of mixed type inhibitor; Corrosion inhibition performance is better when PANI-? is mixed with polyacrylamide, triethanolamine and urea, with a 1:2:1:1 mass ratio. A complex formation between the two components, which was much more effective than the inhibiting action of each additive separately. The concentration of PANI-? is 80mg·L-1 when the inhibition efficiency reaches 92.7%. A synergistic effect was observed between PANI-?and SAA; It is “effects of surface cover geometry” that PANI- ? and SAA mixture inhibition effect on steel Q235 in 0.5mol·L-1 hydrochloric acid; And the adsorption of this inhibitor is also found to obey the modified Langmuir adsorption isotherm in hydrochloric acid media;The influence of Chloride ion might cause desorption of the inhibitor on the iron surface with the immersion time.The anodic corrosion reaction process become faster as steel Q235 is in oilfield water injection. The inhibition efficiency in oilfield water injection increases as the added concentration of PANI-? is increased, and the inhibition efficiency reaches more than 90%when the concentration of PANI-? is 0.4g·L-1; PANI-?is one kind of cathodic corrosioninhibitor. It is “effects of surface cover geometry” that PANI effect on steel Q235 in oilfield water injection; PANI-?is one kind of mixed type inhibitor which cathode play the major role. CMC doping has greatly improved water solubility, enhanced the wettability of the surface of the sample so as to accelerate the rate of migration of the polyaniline molecules. As a result, corrosion performance of PANI- ? have improved deeply. However, the adsorbed film may come off from the electrode surface, that is desorption.