Analisis Kegagalan Waterwall Tube Tipe ASTM A210 Grade A-1 pada Boiler Subcritical PLTU Paiton Unit 8

Putra, Abdullah Akmal Ersa (2023) Analisis Kegagalan Waterwall Tube Tipe ASTM A210 Grade A-1 pada Boiler Subcritical PLTU Paiton Unit 8. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Kegagalan pada waterwall tube dapat menyebabkan kerugian besar dan memaksa sistem boiler harus dilakukan shutdown untuk mencegah kerusakan lebih lanjut pada komponen lainnya. Pada penelitian ini dilakukan analisis kegagalan pada waterwall tube untuk mencegah terjadinya kegagalan serupa. Proses pengumpulan data pada penelitian analisis kegagalan ini meliputi data desain dan operasional boiler, serta pengamatan secara visual untuk mengidentifikasi bentuk dan tampilan kerusakan. Pengujian yang dilakukan meliputi pengujian makrografi, metalografi, Optical Emission Spectrometry (OES) untuk melihat komposisi kimia spesimen, Scanning Electron Microscope (SEM) untuk melihat lapisan oksida dan pola patahan pada spesimen, dan X-Ray Diffraction (X-RD) untuk melihat senyawa yang terdapat pada produk korosi permukaan luar tube. Hasil analisis menunjukkan bahwa kegagalan pada waterwall tube terjadi akibat erosi uap atau steam erosion yang merupakan bagian dari erosi-korosi. Hasil uji makrografi menunjukkan adanya area kegagalan dan penipisan dinding dimulai dari diameter eksternal lalu mengurangi ketebalan hingga dinding menjadi cukup tipis yaitu 0,085 mm dan kurang dari minimum wall thickness sebesar 2,8 mm, tidak mampu menahan tekanan internal, dan akhirnya gagal akibat sobekan beban berlebihan (overload tearing). Pola patahan dimple rupture dapat diamati melalui hasil pengujian SEM. Hasil metalografi tidak menunjukkan adanya degradasi mikrostruktur dan konsisten dengan hasil uji kekerasan. Nilai kekerasan yang didapatkan mencapai 164 hingga 174 HV di area yang jauh dan dekat dengan kegagalan. Komposisi kimia waterwall tube yang diteliti sesuai dengan standar material ASTM A210 Grade A1. Hasil XRD menunjukkan adanya produk korosi berupa Fe2O3 dan Fe3O4 yang juga berkontribusi sebagai penyebab kegagalan erosi-korosi. Untuk mencegah kegagalan serupa terjadi lagi, diperlukan pemeliharaan rutin pada boiler waterwall tube berkala dengan cara pemeriksaan visual (visual inspection), pengecekan ketebalan (thickness inspection), non-destructive testing (NDT) dan tube sampling untuk mendeteksi tanda-tanda awal erosi atau kerusakan pada waterwall tube.
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Waterwall tube is a critical equipment of boilers that have functions to convert water into steam. Mostly tube failure at boiler causing Boiler shut-down, to prevent any secondary damage. The failure analysis objective is to identify the root cause and provide mitigation action then prevent re-occurrence tube failure in the future. Data collection including boiler design and operational, observation with visual inspection to check failure mode performed during the research. The macrography was conducted to confirm failure mechanism using macro lens to inspect macrostructure. Metallography to check the microstructure and provided a micro-structure appearance and performance, a hardness tester to check material hardness, spectrometer to check chemical composition of specimen, Scanning Electron Microscope (SEM) to check oxide layer and fracture mechanism, also X-Ray Diffraction (X-RD) to check corrosion product at surface. The examination has been performed and failure mechanism is identified. Based on failure analysis performed, it was found that the waterwall tube failure occurred due to erosion-corrosion while high pressure steam flow and hit waterwall surface until wastage resulting 0,085 mm thickness, below the minimum wall thickness 2,8 mm, causing tube corrosion. When the high pressure and temperature steam flow spray the waterwall tube for long time, any tube erosion happened, Ferro-Oxide built-up at tube surface due to metal oxidation, also some crack propagation due to overload tearing, it was proven any tube rupture at surface (outside). Preventing re-occurrence tube failure at waterwall tube, it recommends performing visual inspection periodically, slagging removal during boiler operation, tube thickness inspection, and non-destructive testing (NDT) and tube sampling to detect erosion or tube failure at waterwall during unit outage.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Analisis Kegagalan, Failure Analysis, Leakage, Subcritical, Waterwall Tube.
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA169.5 Failure analysis T Technology > TJ Mechanical engineering and machinery > TJ263.5 Boilers (general) T Technology > TN Mining engineering. Metallurgy > TN690 Metallography. Physical metallurgy
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis
Depositing User:	Abdullah Akmal Ersa Putra
Date Deposited:	23 Jul 2023 14:43
Last Modified:	23 Jul 2023 14:43
URI:	http://repository.its.ac.id/id/eprint/98943

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