Synergic Effects Cystein-Ammonium Heptamolybdate and Cystein-Natrium Molibdate Mixtures as Carbon Steel Corrosion Inhibitor in NaCl 1% Solution
Carbon steel is the material that is used in many industries especially used as material oil and gas pipelines. The carbon steel pipe corroded vulnerable from the internal surface due to the flow of the oil is a multi-phase and contain dissolves salts. The corrosion from the internal surface can be...
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| Format: | Final Project |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/32229 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Carbon steel is the material that is used in many industries especially used as material oil and gas pipelines. The carbon steel pipe corroded vulnerable from the internal surface due to the flow of the oil is a multi-phase and contain dissolves salts. The corrosion from the internal surface can be prevented using an inhibitor. This study examined the efficiency of inhibitor cysteine, ammonium heptamolybdate and sodium molybdate. The influence of cysteine, ammonium heptamolybdate and sodium molybdate on inhibition of carbon steel in NaCl 1% saturated by CO2 was investigated by weight loss, Electrochemical Impedance Spectroscopy (EIS) and potentiodynamic polarization (Tafel). The investigation was conducted by varying the concentration at temperatures 25°C and 65°C. Weight loss measurement at 65°C, showed that inhibition efficiency of cysteine 25 ppm reached 72,6%, ammonium heptamolybdate 50 ppm reached 96,3% and sodium molybdate 50 ppm reached 67,4%. The experimental result showed that the inhibition efficiency increases while increasing the inhibitors concentrations. Potentiodynamic polarization (Tafel) curve showed that cysteine, ammonium heptamolybdate and sodium molybdate acted as anodic inhibition in NaCl 1% saturated by CO2, however, cysteine became a cathodic inhibition at higher temperature. The increasing of inhibitions efficiency was supported by EIS measurements. Thermodynamic function of adsorpsion processes were calculated from weight loss methods that cysteine, ammonium heptamolybdate and sodium molybdate are chemical adsorpsion processes. Inhibition efficiencies of mixed inhibitors were also calculated by weight loss methods. The results showed that at 65°C cysteine 25 ppm and ammonium heptamolybdate 25 ppm reached 84,9%, cysteine 15 ppm and sodium molybdate 35 ppm reached 99,2%. According to the results, it has been concluded that there is a synergistic between mixed inhibitors of cysteine – ammonium heptamolybdate and also cysteine - sodium molybdate compared with single inhibitor |
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