| Acidification is an important treatment in oil development,and corrosion inhibitor can effectively prevent the serious corrosion of mental equipment.Imidazoline quaternary ammonium salt(IQAS)series and propargyl alcohol series corrosion inhibitor have been studied in this paper.The inhibitive effect has been evaluated by weght loss method,Tafel polarization and impedance measurements.Results reveal that the inhibition efficiency reached 85.20% with 1000mg/L imidazoline quaternary ammonium salt at 60? for carbon steel in 10% H2SO4,which decreased to 58.54% at 80?.The optimal ratio of composite inhibitor was 500 mg/L IQAS,250 mg/L KI and 1200 mg/L polymer ?,which the inhibition efficiency reached 99.98% at 60? in H2SO4 and about 82.50% at 120?.Polarization curve showed that compound inhibitor was a mixed-type inhibitor mainly with anodic predominamce.Impedance showed that inhibitors decreased the corrosion process with the charge transfer resistance increased.The results of propargyl alcohol indicate that in 10% H2SO4 the inhibition efficiency reached 93.04% with 120 mg/L at 60? for carbon steel and then it decreased with temperature increased.Considering the toxicity and temperature,the composite inhibitors of propargyl alcohol,KI and polymer ? were 15 mg/L,250 mg/L and 1600 mg/L,and which made the inhibition efficiency reach 92.87% at 120?.Electrochemical showed that compound inhibitor was a mixed-type inhibitor and fit with the wight loss method.The adsorption of the two compound inhibitors on mild steel surface is chemical adsorption and obey Langmuir adsorption isotherm.The adsorption is spontaneous and exothermic.All the results indicate that propargyl alcohol composite inhibitor has better inhibitive effect than imidazoline quaternary ammonium salt.However,the latter has advantage in enviromental protection.The temperature tolerance of them is 120? and compound inhibitors are steady properties and satisfy the requirements of acidification. |
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