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Abstrak :
Corrosion is one of some necessary field that must be concorned by maritime and ship industries in Indonesia. The phenomenon of corrosion should be more attended, because it makes much money lost unpredictly. Corrosion couldn,t be avoid because the process happens natyrally but corrosion must be controlled to minimize the negative effects, specially in economics technics and safety fields. One of some popular methods to control the corrosion process in cathodic protection methods, with sacrificial anode. This research observed the effectivity of znanode (type S-3) that is used to protect a kind of material as cathode. The cathode material is A grade of mild steels, a material that is commonly used for many sea water constructions espicially for ship building materials. The observation was taken in fluid laboratory, marine engineering departement, the faculty of marine engineering & science, Hang Tuah University Surabaya. The weigh of sacrificial anode and the cathode is 1:4. They are connected and immersed in a model vessel with 35%o salinity sea water as corrosion media. This research presents that the average weight lost of the sacrificial anode is 1.637% and the average weigh lost of the cathode is 0.170% in 16 weeks observation. The calculation predicted that the sacrificial anode will be lost 5.5% of the weight in a year.

Abstrak :
Summary: A companion to the title Corrosion Chemistry, this volume covers both the theoretical aspects of cathodic protection and the practical applications of the technology, including the most cutting-edge processes and theories

Abstrak :
Dilakukan survey resistivitas tanah per 1 (satu) kilometer sepanjang pipeline dengan menggunakan metode four pin mengggunakan alat soil box untuk mendapatkan data perancangan proteksi katodik. Dari perhitungan dengan metode masa dan metode arus listrik yang dikeluarkan diperoleh jumlah anoda magnesium dengan spesifikasi berat 14,5 Kg, penampang melintang 0.015 m² dan panjang 0.55 m pada setiap satu kilometer pipa dengan spacing 0.914 m. Berdasarkan referensi data pipa, lingkungan, spesifikasi anoda korban, spesifikasi material urug dan resistivitas tanah, perancangan jumlah anoda korban yang dipasang pada pipa dihitung. Pengecekan perlindungan proteksi katodik dilakukan dengan pengetesan potensial polarisasi dan perhitungan hambatan total dilapangan sehingga arus korosi dan laju korosinya dapat diperkirakan. Perbandingan dilakukan dengan menguji laju korosi material API 5L Grade B di laboratorium dengan alat potensiostat yang menggunakan metode polarisasi sehingga kriteria perlindungan berdasarkan standard NACE RP 0169 dapat diklarifikasi. Penelitian juga dikembangkan dengan melihat perilaku korosi material pipa dengan pengujian struktur mikro, mekanik dan komposisi kimia pada pipa baru dan yang pipa telah terkorosi (akibat alat uji potensiostat). Juga sebagai pembanding, sampel pipa gagal akibat korosi turut diuji struktur mikro dan komposisi kimianya. Data dari pengujian ini akan memberikan gambaran mengenai disain umur pipa yang dirancang untuk kondisi dengan tekanan dan temperatur tertentu. ......A survey of soil resistivity per 1 (one) kilometer along the pipeline using the four pin method of a soil box tool to obtain cathodic protection design data. From the calculation with the mass method and the electric current method that was released, the number of magnesium anodes with a weight specification of 14.5 Kg, a cross section of 0.015 m2 and a length of 0.55 m in per one kilometer pipeline with spacing of 0.914 m. Based on pipe data references, environment, sacrificial anode specifications, load material specifications and soil resistivity, the design of quantity scarifical anodes installed on the pipe is calculated. Checking cathodic protection protection is done by testing the potential of polarization and calculating the total resistance in the field so that the corrosion current and the corrosion rate can be estimated. Comparison was carried out by testing the corrosion rate of API 5L Grade B material in the laboratory with a potentiostat device using the polarization method so that the protection criteria based on the NACE standard of Rp. 0169 could be verified. Research was also developed by looking at the corrosion behavior of pipe material by testing the microstructure, mechanics and chemical composition of the new pipe and the pipe has been corroded (due to the potentiostat test equipment). Also as a comparison, the defect pipe samples due to corrosion were tested for microstructure and chemical composition. Data from this test will provide an overview of the design life of pipes designed for conditions with certain pressure and temperature.

Abstrak :
Inspeksi ketebalan dinding aktual menggunakan ultrasonic testing (UT) gauge dan inspeksi potensial katodik menggunakan cathodic protection (CP) gun merupakan contoh metode inspeksi yang umum digunakan dalam menilai kelayakan operasi pipa bawah laut. Namun hasil keluaran metode ini sering kali memiliki keterbatasan (Okyere, 2019; Langenberg, Marklein, & Mayer, 2012) sehingga diperlukan metode lain untuk mensimulasikan kelayakan operasi pipa bawah laut. Penelitian ini akan mengusulkan metode yang lebih sistematis dalam mensimulasikan kelayakan operasi pipa bawah laut milik KKKS. Variabel yang menentukan kelayakan pipa berdasarkan ketebalan dinding dalam penelitian ini adalah persentase kehilangan dinding, ketebalan dinding kebutuhan, dan umur sisa pipa, sedangkan variabel yang menentukan kelayakan sistem CP adalah potensial katodik pada pipa. Hasil penelitian menunjukan bahwa kedua pipa terseut masih dinilai aman untuk digunakan karena tebal dinding aktual masih berada diatas ketebalan dinding kebutuhan. Sistem proteksi katodik kedua pipa tersebut juga masih layak dikarenakan rentang potensial katodik yang dimiliki pipa utara dan selatan berada dalam rentang batas aman yakni 0,80 V hingga 1,10 V. Diharapkan hasil penelitian ini dapat mengantisipasi kegagalan pada jalur pipa bawah laut yang dapat mengakibatkan kerugian. ......Inspection of actual wall thickness using ultrasonic testing gauges (UT) and potential cathodic inspection using cathodic protection (CP) gun are examples of common inspection methods used in assessing the feasibility of underwater pipeline operation. However, the outputs of this method often have limitations (Okyere, 2019; Langenberg, Marklein, & Mayer, 2012), so other methods are needed to simulate the feasibility of underwater pipeline operations. This research will discuss more comprehensive methods in simulating the underwater pipeline operation which owned by KKKS. The variables that being used in determining the feasibility of the actual wall thickness of subsea pipe in this study are wall loss, wall thickness requirements, and the remaining life of the pipe, while the variable that determines the feasibility of the CP system is the cathodic potential of the pipe. The results showed that the two pipes were still safe to use because wall thickness was still needed. The cathodic protection system of the two pipes is also still worth considering based on the cathodic potential of the north and south pipelines within the safe limit range of -0.80 V to -1.10 V. It is expected that the results of this study can anticipate the failure of subsea pipeline.

Abstrak :
Salah satu kelemahan yang dihadapi saat bekerja dengan mesin angkatan laut adalah korosi, yang selanjutnya menyebabkan kerusakan parah pada kapal. Oleh karena itu, diperlukan proteksi khusus bagi kapal angkatan laut untuk mencegah terjadinya korosi tersebut. Skripsi ini bertujuan untuk melokalisasi kerusakan multiple coating yang terjadi pada lambung kapal menggunakan model kapal generik yang dikombinasikan dengan jaringan syaraf tiruan (JST). Simulasi numerik menggunakan perangkat lunak FEM COMSOL Multiphysics dilakukan untuk menghitung tanda tangan potensial listrik bawah air (UEP) yang sesuai. Kerusakan lapisan yang disebutkan di atas didefinisikan di permukaan lambung secara acak dan arus yang dipengaruhi oleh sistem perlindungan katodik arus terkesan (ICCP) serta tanda tangan UEP digunakan sebagai parameter input untuk melatih ANN untuk lebih melokalisasi kerusakan lapisan. Kerusakan lapisan ganda dilacak secara terpisah karena sangat kecil kemungkinan kerusakan lapisan tersebut terjadi secara bersamaan ketika kapal berada dalam kondisi perairan terbuka. Akurasi prediksi dievaluasi oleh JST terlatih dan diuji lebih lanjut untuk model kapal sektoral masing-masing menggunakan 8 dan 12 sektor. Dengan metode deep learning ini didapatkan akurasi sekitar 80% untuk kerusakan lapisan pertama, namun akurasi untuk lokalisasi kerusakan lapisan kedua hanya mencapai 40% dengan model kapal generik mempertimbangkan 12 sektor. Namun, karena implementasi kerusakan kedua di kapal 12 sektor sulit diprediksi oleh JST, tidak masuk akal untuk merealisasikan sektor tambahan. ......One of the disadvantages that is faced when working with naval machinery is corrosion which further causes severe damage to the ship. Therefore, specific protection is needed in the naval vessel in order to prevent said corrosion. This thesis aims to localize multiple coating damages that occur in the ship hull using a generic ship model. The numerical simulation using the FEM software COMSOL Multiphysics is performed to calculate corresponding underwater electric potential (UEP) signature. The aforementioned coating damages are defined in the ship hull surface in a random manner and the impressed currents impressed by the ICCP current as well as the UEP signatures are used as input parameters to train the artificial neural network (ANN) to further localize the coating damage. The multiple coating damages are tracked separately since it is highly unlikely for said coating damages to occur simultaneously when the ship is in open water condition. The prediction test is done by generating the ANN and is tested for the prediction accuracy in the 8 and 12-sector ship. With this deep learning method, approximately 80% of accuracy is obtained for the first coating damage, however the accuracy for the second coating damage localization only reaches 40% with the generic ship model which is divided into 12 sectors taken into consideration. However, since the implementation of the second damage in the 12-sector ship was hard for the ANN to predict, it does not make sense to realize additional sectors.

Abstrak :
Engineering design calculations for tank bottom sections, including direct current requirements and voltage calculations, followed by additional structures, such as electrical grounding systems, have already been successfully implemented and controlled in field conditions. Furthermore, the effect of soil resistivity in layers, oxygen content and the pH value of the soil against the disproportionate IR-Drop voltage, including its effect on potential distribution, have been already successfully observed. Other influences, such as the depth and location of the anode groundbed determination along with the establishment of impressed current cathodic protection related to the main tools and equipment, such as external corrosion control methods, have been defined as the most effective ways in order to control potential distribution against the additional structures. Persuant to the verification results from the site located at Marangkayu, East Borneo, it has been determined that high soil resistivity could cause error readings in accordance with the accumulation results of the true readings and the IR-Drop voltage, since under real conditions, the tank structure would have received less current flow from an anode compared to a lower result. Naturally, a low pH value from the soil would decrease soil resistivity and enhance potential distribution from the anodes to the tank structures. The results show that the cathodic protection required 10 additional anodes, (each one is of a tubular mixed metal oxide) with a DC supply at minimum amperage of 154 Amps and a minimum voltage supply of 32 Volts. During the research, it was identified that high soil resistivity above 3000 ohm-cm would cause error readings. Naturally, acidic soil is in the region of pH 5-7 value, which would decrease soil resistivity and enhance the potential distribution from the anode to the tank structure.