Inhibisi Korosi Baja Karbon di dalam Larutan Karbonat-bikarbonat
Keywords:
baja karbon, inhibitor, karbonat-bikarbonat, korosi, natrium benzoat, carbon steel, carbonat-bicarbonat, corrosion, sodium benzoateAbstract
Sari. Sistem absorpsi CO2 yang menggunakan absorben K2CO3 merupakan salah satu satuan operasi yang rawan korosi, terutama di bagian yang berhubungan dengan larutan "kaya" yang mengandung KHCO3. Baja karbon, yang biasa digunakan sebagai bahan konstruksi pada sistem absorpsi CO2 terkorosi oleh larutan K2CO3 + KHCO3 tetapi juga bersifat mampu pasif dalam larutan tersebut. Oleh sebab itu, korosi pada sistem absorpsi CO2 dapat dikendalikan dengan menggunakan inhibitor pasivator seperti KVO3. Dari hasil pengujian yang telah dilakukan, ternyata KVO3 dengan dosis 20 g/dm3 efektif menurunkan laju korosi baja karbon dalam larutan K2CO3 + KHCO3 pada suhu 100 C, dan turbulensi yang tinggi. Lapisan pasif yang terbentuk dengan penambahan inhibitor vanadate terutama terdiri dari n-Fe2O3 dan FeVO4 Na-benzoat, yang juga inhibitor pasivator, dapat menurunkan laju korosi baja karbon dalam lingkungan yang sama dengan efektifitas yang tidak jauh berbeda, tetapi dengan dosis lebih rendah (14 g/dm3). Lapisan pasif yang dihasilkan dengan penambahan inhibitor Na-benzoat terdiri dari n-Fe2O3 dan Fe2(OH)2CO3.
Corrosion Inhibition of Carbon-Steel in Carbonate-Bicarbonate Solution
Abstract. Carbondioxide (CO2) absorption system, using K2CO3 as absorbent, is one of the absorption unit which is susceptible to corrosion attack, especially the parts contacting the KHCO3 rich solution. Carbon steel which used to be the construction material of CO2 absorption system, is susceptible to corrosion in K2CO3 + KHCO3 solution with a passivation tendency. The use of passivating inhibitor, especially KVO3, is one of the most popular corrosion prevention method. Experimental results show that 20 g/dm3 KVO3 is effective to inhibit corrosion of carbon steel in K2CO3 + KHCO3 solution at temperature up to 100C and high turbulence. This passivation is due to the formation of protective layer which consists of η-Fe2O3 and FeVO4. Another passivating inhibitor, Na-benzoate, is found to be similarly effective to KVO3 in the same testing conditions. The passive film, formed by the addition Na-benzoate, consists of η-Fe2O3 and Fe2(OH)2CO3.
References
D.H.Davies and G.T.Burstein, The effect of Bicarbonate on The Corrosion and Passivation of lron, Corrosion, 36 (8), (1980).
ASTM G 59-78, Standard Practice for Conducting Potentiodynamic Polarization Resistance Measurement, Annual Book of ASTM Standard, (1981), 964.
NACE, Standard TM-02-70, Method of Conducting Controlled Velocity Laboratory Test, NACE, Texas, (1970).
G.I. Ogundele, W.E. Write, Some Observation on Corrosion of Carbon Steel in Aqueous Environment Containing Carbon Dioxide, Corrosion, 42(2), 71-78, (1986).
E.B. Castro, C.R. Valentini, C.A. Moina, J.R. Vilche, A.J. Arvia, The Influence of lonic Composition on the Electrodissolution and Passivation of Iron Electrodes in Potassium Carbonate-Bicarbonate Solution in the 8.4-10.5 pH range at 25 derajat C, Corrosion Science, 26(10), 781-793, (1986).
P. Hancock, J.E.O Mayne, The Inhibition of The Corrosion of Iron in Neutral and Alkaline Solution l, J. Appl. Chem., 9(7), 350-351, (1959).
Herbert H. Uhlig, Corrosion and Corrosion Control, John Wiley & Sons, New York, (1971).
C. De Waard, D.E. Millians, Carbonic Acid Corrosion of Steel, Corrosion, 31(5), 177-181, (1975).
Philippe V. Scheers, Francois J. Strauss, Electrochemical Study of The Relative Influence of Benzoate and Chloride Ions on The Corrosion of Mild Steel in Neutral Solutiors, S. Afr. Tydskr. Chem., 39(1), 27-32, (1985).
C.R. Valentini, C.A. Moina J.R. Vilche, A.J. Arvia, The Electrochemical Behaviour of Iron irr Stagnant and Stirred Potassium Carbonate-Bicarbonate Solutions in The 0-75 derajat C Suhue Range, Corrosion Science, 25(11), 985-997, (1985).
E.B. Castro, J.R. Vitche, A.J. Arvia, lron Dissolution and Passivation in K2CO3-KHCO3 Solutions, Rotating Ring Disc Electrode and XPS Studies, Corrosion Science, 32(1), 37-49, (1991).
F. Wormwell, A.d. Mercer, Sodium Benzoate and Other Metal Benzoate as Corrosion-Inhibitors in Water and Aqueous Solutions, J. Appl. Chem., 2(3), 157-160, (1952).
I.L. Rozenfeld, Corrosion Inhibitor, Mc Graw Hill, Inc., New York, (1981), 158-170.
Isdiriayani, M. Syahri, The Corrosium Inhibition of Carbon Steel Using Sodium Benzoate in Carbonate-Bicarbonate Solution, Proceedings of The 10th Asia Pacific Corrosion Control Conference, Bali, Indonesia 1997.
