Kajian Korosi dan Proteksi Katodik Sistem Anoda Korban Pada Pipa Transportasi Crude Oil Pipeline D di Kecamatan Lemahabang, Kabupaten Karawang, Provinsi Jawa Barat

Abstract

Abstract. The process of transporting crude oil generally carried out using metal-based pipes. The metals used in transportation pipes have good resistance to temperature and pressure, but metal pipes experience corrosion due to their interacion with he surrounding environment. The environment is soil, water, air, natural gas, or crude oil. The loss caused by corrosion is that causes a reduction in the thickness of the transportation pipe so that it will have an impact on damage or leakage of the pipe and the remaining service life of the pipe is low. Therefore, it is necessary to study the corrosion of transportation pipes so that the remaining service life of the pipes can reach its design life. This research was conducted on a transportation pipe for crude oil pipeline D transportation pipe along the 1,743 m, which is located under the ground surface. This study aims to determine the type of corrosion, the level of cathodic protection of the sacrificial anode system, the corrosion rate of pipes and the remaining service life of the pipe and the external environmental factors that influenced. The research methodology is measuring the pipe thickness reduction of the pipe to determine the value of the corrosion rate and the remaining service life of the pipe based on API 570 standards. The pipe thickness measurement was carried out using an Ultrasonic Thickness Gauge Panametrics MG 2 DL at 8 test points. The study area’s environmental conditions are pH 6.1 – 6.5, which is in the acid cathegory, average air temperature is 27°C, and soil resistivity is 2,441 – 3,384 ohm.cm, which is included in the highly corrosive to corrosive class. The types of corrosion that occur in transportation pipe crude oil pipeline D are uniform corrosion and erosion corrosion. External environmental factors including pH and soil resistivity have a significant effect on the corrosion rate and the remaining service life. The potential value of sacrificial anode cathodic protection is -1,043 to -836 mV vs CSE they are included in protected level – there is protection based on the NACE RP0169 standard. The corrosion rate ranges from 0.4008 – 0.4262 mm/year, which is included in the good category based on the relative corrosion resistance of the steel. The lifespan of pipes is 13 years, and the remaining service life of the pipe ranges from 7.27 – 8.56 years, thus the pipe is estimated to exceed the pipe design life is 20 years.

Keywords :  Carbon Steel Pipe, Crude Oil, Cathodic Protection, Corrosion Rate, Remaining Service Life

Abstraks. Proses transportasi minyak bumi (crude oil) umumnya dilakukan dengan menggunakan pipa berbahan dasar logam. Logam yang digunakan pada pipa transportasi memiliki sifat ketahanan yang baik terhadap temperatur dan tekanan, akan tetapi pipa logam mengalami korosi akibat berinteraksi dengan lingkungan di sekitarnya. Lingkungan tersebut berupa tanah, air, udara gas bumi, ataupun crude oil. Kerugian yang diakibatkan oleh korosi yaitu enyebabkan pengurangan ketebalan pada pipa transportasi, sehingga akan berdampak pada kerusakan ataupun kebocoran pipa dan sisa umur pakai pipa menjadi rendah. Oleh karena itu, diperlukan adanya kajian korosi pada pipa transportasi agar sisa umur pakai pipa mencapai umur desainnya. Penelitian ini dilakukan pada pipa transportasi crude oil pipeline D sepanjang 1.743 m yang terletak di bawah permukaan tanah. Penelitian ini bertujuan untuk mengetahui jenis korosi, tingkat proteksi katodik sistem anoda korban, laju korosi (Corrosion Rate/CR) pipa dan sisa umur pakai pipa (Remaining Service Life/RSL) serta faktor-faktor lingkungan eksternal yang mempengaruhinya. Metodologi dalam penelitian ini yaitu pengukuran pengurangan ketebalan pipa untuk menentukan nilai laju korosi dan sisa umur pakai pipa berdasarkan standar API 570. Pengukuran ketebalan pipa dilakukan dengan menggunakan alat Ultrasonic Thickness Gauge Panametrics MG 2 DL pada 8 test point. Kondisi lingkungan pada daerah penelitian yaitu pH 6,1 – 6,5 yang termasuk kategori asam, teperatur udara rata-rata 27°C dan resistivitas tanah 2.441 0 3.384 ohm.cm yang termasuk ke dalam kategori highly corrosive hingga corrosive. Jenis korosi yang terjadi pada pipa transportasi crude oil pipeline D yaitu korosi merata dan korosi erosi. Faktor-faktor lingkungan eksternal meliputi pH tanah dan resistivitas tanah cukup berpengaruh terhadap laju korosi dan sisa umur pakai pipa. Nlai potensial proteksi katodik sistem anoda korban berkisar antara -1.043 sampai -836 mV vs CSE yang menunjukkan bahwa tingkat proteksi masuk ke dalam proteksi yaitu terproteksi – ada proteksi berdasarkan standar NACE RP0169. Laju korosi berkisar antara 0,4008 – 0,4262 mm/tahun yang termasuk ke dalam kategori good berdasarkan ketahanan korosi relatif baja. Umur pakai pipa yaitu 13 tahun dan sisa umur pakai pipa berkisar antara 7,27 – 8,56 tahun, dengan demikian pipa dapat digunakan mencapai umur desain pipa yaitu 20 tahun.

Kata kunci :  Pipa Baja Karbon, Crude Oil, Proteksi Katodik, Laju Korosi, Sisa Umur Pakai