Analisis Penilaian Sisa Umur Heat Recovery Steam Genearator (HRSG) Berdasarkan Standar American Society of Mechanical Engineers (ASME)

Danang Priambada, Ir. Felixtianus. Eko Wismo Winarto, M.Sc., Ph.D.

2025 | Tesis | MAGISTER TERAPAN KESELAMATAN DAN KESEHATAN KERJA

Heat Recovery Steam Generator (HRSG) merupakan salah satu komponen vital pada sistem pembangkit listrik tenaga gas dan uap (PLTGU) yang berfungsi memanfaatkan gas buang turbin gas untuk menghasilkan uap. Seiring waktu operasi, HRSG mengalami penurunan performa akibat degradasi material seperti korosi, creep, dan retak pada pipa maupun sambungan las. Evaluasi kondisi material dan estimasi sisa umur menjadi langkah penting untuk menjamin keselamatan, keandalan, serta efisiensi operasi pembangkit.

Penelitian ini bertujuan untuk melakukan penilaian sisa umur HRSG Unit 2 menggunakan pendekatan in situ metalurgi sesuai standar ASME FFS-1/API 579. Metode yang digunakan meliputi inspeksi visual, uji tak merusak (Non-Destructive Testing/NDT) berupa Dye Penetrant Test (DPT), Magnetic Particle Test (MPT), Ultrasonic Thickness Measurement (UTM), dan Ultrasonic Flaw Detection (UFD), serta pengujian pendukung berupa field metallography, hardness test, Borescope inspection, dimensional examination, dan analisis beban pada pipa.

Hasil penelitian menunjukkan bahwa ketebalan aktual pipa HRSG masih berada pada kisaran 58–69?ri Minimum Wall Thickness (mwt), dengan nilai kekerasan material berkisar 120–220 HV, sesuai dengan standar desain. Analisis mikrostruktur tidak menemukan degradasi signifikan yang berpotensi menyebabkan kegagalan segera. Berdasarkan Remaining Life Assessment (RLA), HRSG Unit 2 masih memiliki estimasi sisa umur operasional sekitar 10–15 tahun, dengan catatan dilakukan pemeliharaan preventif secara konsisten.

Kesimpulan penelitian ini menegaskan bahwa HRSG Unit 2 masih dalam kondisi operasional aman dan reliabel. Pendekatan in situ metalurgi berbasis standar ASME terbukti efektif untuk menilai kondisi aktual, memperkirakan sisa umur, serta memberikan dasar teknis bagi strategi pemeliharaan berbasis risiko yang lebih terarah. Hasil penelitian ini diharapkan dapat mendukung peningkatan availability, reliability, efficiency, dan safety pada sistem pembangkit PLTGU.

Heat Recovery Steam Generator (HRSG) is one of the most critical components in a gas–steam combined cycle power plant (PLTGU), functioning to utilize exhaust gas from the gas turbine to produce steam. Over time, HRSG performance gradually decreases due to material degradation such as corrosion, creep, and cracking in tubes and welded joints. Therefore, evaluating material condition and estimating the remaining life are essential steps to ensure safety, reliability, and operational efficiency.

This study aims to assess the remaining life of HRSG Unit 2 using an in-situ metallurgical approach based on ASME FFS-1/API 579 standards. The methods applied include visual inspection and various Non-Destructive Testing (NDT) techniques such as Dye Penetrant Test (DPT), Magnetic Particle Test (MPT), Ultrasonic Thickness Measurement (UTM), and Ultrasonic Flaw Detection (UFD). Additional supporting examinations were also performed, including field metallography, hardness testing, borescope inspection, dimensional checks, and pipe stress analysis.

The results show that the actual tube wall thickness of the HRSG remains within 58–69% of the Minimum Wall Thickness (mwt), while the material hardness values range from 120 to 220 HV, still compliant with design standards. Microstructural analysis did not reveal any significant degradation that could potentially lead to immediate failure. Based on the Remaining Life Assessment (RLA), HRSG Unit 2 is estimated to still have an operational life of approximately 10–15 years, provided that preventive maintenance is carried out consistently.

In conclusion, HRSG Unit 2 remains in a safe and reliable operating condition. The in-situ metallurgical approach based on ASME standards has proven effective in evaluating actual material condition, estimating remaining life, and providing a solid technical basis for a more targeted risk-based maintenance strategy. The outcomes of this research are expected to support improvements in availability, reliability, efficiency, and safety of PLTGU power generation systems.

Kata Kunci : Heat Recovery Steam Generator, ASME FFS-1/API 579, in situ metalurgi, Remaining Life Assessment, Non-Destructive Testing.