Hasil Pencarian  ::  Simpan CSV :: Kembali

"Korosi yang disebabkan oleh karbondioksida (CO2) pada pipa baja karbon dan peralatan di pengolahan minyak dan gas sangat umum terjadi. CO2 larut dalam air menghasilkan asam karbonat (H2CO3) yang mempunyai sifat yang lebih korosif dibanding asam klorida (HCL) pada pH yang sama. Electrochemical impedance spectroscopy dan linear polarization resistance digunakan untuk mengetahui fenomena proses yang terjadi selama proses adsorbsi inhibitor di permukaan logam. Variasi temperature dan konsentrasi dari inhibitor dilakukan untuk mengetahui kemampuan inhibisi inhibitor dan mekanisme inhibisi. Penelitian ini dilakukan pada baja karbon A106 grB di dalam lingkungan 3% NaCl. Konsentrasi inhibitor bervariasi dari 0,5,15, dan 40 ppm dan dengan variasi temperature di 40 0C dan 90 0C. Pada temperature 40 0C laju korosi menunjukan 213,9 MPY pada lingkungan tanpa penambahan inhibitor , dan akan turun drastis ke 22,4 MPY ketika 5 ppm inhibitor ditambahkan ke lingkungan, dengan effisiensi inhibisi 90%. Penambahan konsentrasi inhibitor sampai 40 ppm meningkatkan effisiensi inhibisi sampai 98%. Penambahan konsentrasi inhibitor berbasis Imidazoline dari dari 0 ppm sampai 5 ppm pada temperature 90 0C dapat menghasilkan penurunan laju korosi yang signifikan yaitu dari 173,3 MPY menjadi 31,67 MPY, dengan effisiensi inhibisi 82%. Dengan penambahan konsentrasi inhibitor sebanyak 40 ppm akan menaikan effisiensi inhibisi sampai 99,99 %. Mekanisme penghambatan laju korosi terjadi sebagai akibat terbentuknya ikatan polar (O-H dan N-H) yang berikatan dengan permukaan logam melalui proses chemisorption.

---

Corrosion caused by carbon dioxide (CO2) in carbon steel pipes and equipment in oil and gas processing is very common. Water soluble CO2 produces carbonic acid (H2CO3) which has more corrosive properties than hydrochloric acid (HCL) at the same pH. Electrochemical impedance spectroscopy and linear polarization resistance are used to determine the processes that occur during the adsorbs inhibitor process on the metal surface. Variation of concentration of the inhibitor is conducted to determine the ability of inhibitor inhibition and inhibition mechanism. This research was conducted on A106 gr. B carbon steel in an environment of 3% NaCl. The inhibitor concentration varies from 0,5,15, and 40 ppm at 40 0C. At temperatures of 400C the corrosion rate shows 213.9 MPY in the environment without the addition of inhibitors, and will drop dramatically to 22.4 MPY when 5 ppm inhibitors are added to the environment. Electrochemical Impedance Spectroscopy is used to study inhibition mechanism. Increasing the concentration of Imidazoline based inhibitors from 0 ppm to 5 ppm at 90 0C can produce a significant decrease in corrosion rate from 173.3 MPY to 31.67 MPY, with 82% inhibition efficiency. With the addition of inhibitor concentrations up to 40 ppm will increase inhibition efficiency to 99,99 %. The mechanism of inhibition of corrosion rate occurs as a result of the formation of polar bonds (O-H and N-H) that bind to the metal surface through a chemisorption process."

"Korosi merupakan masalah utama dalam sistem resirkulasi air pendingin semi-tertutup saat sistem off-line dan baru dioperasikan. Dalam makalah ini, tahapan metode evaluasi chemical cleaning & pasivasi pada pengendalian masalah korosi untuk pipa baja karbon dalam sistem pendingin semi-tertutup dipelajari secara ekstensif selama pra-comissioning. Hasil penelitian menunjukkan bahwa citric acid dan EDTA, sebagai chemical cleaning efektif menghilangkan tubercules oksida besi dan karat yang terakumulasi selama kegiatan fabrikasi, penyimpanan, dan kontruksi. Pada tahap selanjutnya, poly- and ortho-phosphate bersama dengan zinc sebagai inhibitor korosi pasivasi membentuk lapisan film pelindung chemi-absorbed pada permukaan baja karbon. Pengaruhnya pada pipa baja karbon dipelajari melalui nilai target analisis air dan corrater monitoring. Analisa kualitas air dan corrater monitoring menunjukkan konsentrasi Iron content rata-rata 593,63 ppm yang dijaga setelah chemical cleaning dan laju korosi 2,34 mpy diperoleh setelah pasivasi. Hasil uji korosi ditampilkan menggunakaan teknik potensiodinamik. Pengarang menganalisa perbandingan tiga (3) tahapan kategori sampel, yaitu pre cleaning, chemical cleaning, dan pasivasi. Pada kurva tafel plot jelas terlihat langsung laju korosi perbedaannya. Pengurangan laju korosi disebabkan karena pembentukkan lapisan film pelindung oleh inhibitor dan stabilisasi lapisan film pelindung. Studi impedansi arus AC mendukung adanya peningkatan lapisan pada permukaan baja karbon dengan inhibitor, membentuk film pelindung. Verifikasi lebih lanjut dengan karakterisasi permukaan menggunakan spektrum SEM dan EDS pada permukaan baja karbon dengan inhibitor menunjukkan puncak spektrum elemen O, P, Zn, dan Ca, disamping puncak Fe.

---

Corrosion are main problems on carbon steel pipes in the recirculating semi-closed cooling water system when the system is off-line and newly operated. In this paper, chemical cleaning & passivation evaluation of sequence method on control of these problems for carbon steel pipes in the recirculating semi-closed cooling water system was extensively studied during precommissioning. The results showed that citric acid and EDTA, as chemical cleaning effectively remove iron oxide tubercles that have accumulated during fabrication, storage, and construction activities. At the same time, elevated levels of poly- and ortho-phosphate are maintained along with zinc as corrosion inhibitor to develop a chemi-absorbed passivating protective film on the carbon steel surface. The influence of these on carbon steel pipes were studied through water analysis and corrater monitoring. Water analysis and corrater monitoring showed that iron content 593.63 ppm are maintained after cleaning and corrosion rate of 2.34 mpy was obtained after passivation. The results of corrosion tests using potensiodynamic technique are presented. Authors analized in sequence different three parts of the features samples carbon steel such as pre-cleaning, chemical cleaning, and simulated passivation. These are clearly distinguished on the tafel plot of an instantaneous corrosion rate. The decrease  is caused by the formation of a protective film with the participation of the inhibitor and a subsequent stabilization of these film. AC impedance study by EIS supports the increase in surface coverage of the carbon steel surface by the inhibitor, forming a protective film. Further verification comes from the surface characterization of the inhibited metal surface by SEM and EDS spectrum revealed O, P, Zn, and Ca, beside Fe peaks. "