Evaluasi Penggantian Material Tube Reheater Panel 33-37 Pada PLTU Berkapasitas 600 MW

Tertiasani, Mega (2018) Evaluasi Penggantian Material Tube Reheater Panel 33-37 Pada PLTU Berkapasitas 600 MW. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Instalasi reheater dalam boiler berperan untuk memanaskan kembali uap yang telah mengalami ekspansi dalam turbin. Uap yang keluar turbin berupa cold steam sehingga perlu dipanaskan kembali dan dimasukkan kembali ke dalam boiler. Dengan adanya proses reheat maka akan meningkatkan efisiensi PLTU. Tube dengan kode J, K dan M (material T91) mengalami penghitaman. Sedangkan, tube dengan kode B dan F (material TP304H) tidak mengalami penghitaman. Beberapa tube yang menghitam disebabkan overheating. Setelah dilakukan pengujian material, ditemukan bahwa tube pada panel 33 row 8 (material T91) terpapar temperatur yang melebihi batas izin maksimal. Cleaning pada tube yang menghitam tidak dapat dilakukan karena jika dibersihkan (brushing) permukaan tube akan terkikis dan tube akan semakin menipis. Penipisan tube akan meningkatkan resiko kegagalan operasi sistem. Salah satu alternatif yang dapat dilakukan adalah penggantian material tube dari T91 menjadi TP304H. Dalam tugas akhir ini dilakukan analisis perpindahan panas pada reheater sebelum dan sesudah penggantian material. Analisis dilakukan dengan membahas koefisien konveksi di dalam tube, koefisien konveksi di luar tube, koefisien radiasi dan faktor pengotor di dalam dan di luar tube. Dalam analisis dilakukan perhitungan menggunakan metode LMTD, sehingga nilai laju perpindahan panas sebelum dan sesudah penggantian material dapat dibandingkan. Dari hasil analisis, diperoleh nilai laju perpindahan panas maksimum sebelum dan sesudah penggantian material sebesar 6445.27 kW dan 6270.62 kW, sedangkan nilai laju perpindahan panas minimum sebelum dan sesudah penggantian material sebesar 4573.61 kW dan 4421.5 kW. Laju perpindahan panas yang menurun menunjukkan bahwa laju perpindahan panas pada material T91 lebih besar dari material TP304H. Perbedaan nilai laju perpindahan panas sebelum dan sesudah penggantian material dipengaruhi oleh nilai konduktivitas termal masing-masing material. Dari sudut pandang analisis termal, penggantian material tube T91 menjadi TP304H tidak direkomendasikan. ========================================================= Abstract Reheater installations in the boiler play a role in reheating steam which has been expanded in the turbine. The steam that comes out of the turbine is cold steam so it needs to be reheated and put back into the boiler. With the reheat process will increase the efficiency of PLTU. Tube with code J, K and M (material T91) experience blackening. Meanwhile, the tube with code B and F (TP304H material) does not experience blackout. Some blackened tubes were caused by overheating. After material tested, it was found that the tube on the 33 row 8 panel (T91 material) was exposed to temperatures that exceeded the maximum permit limit. Cleaning on a blackened tube cannot be done because if it is cleaned (brushing) the surface of the tube will be eroded and the tube will thin out. Tube thinning will increase the risk of system operation failure. One alternative that can be done is the replacement of tube material from T91 to TP304H. In this final project, an analysis of heat transfer in the reheater is done before and after material replacement. The analysis was carried out by discussing the convection coefficient inside the tube, the convection coefficient outside the tube, the radiation coefficient and the impurity factors inside and outside the tube. In the analysis, the calculation is using the LMTD method, so that the heat transfer rate before and after the material replacement can be compared. From the results of the analysis, the maximum heat transfer rate obtained before and after material replacement is 6445.27 kW and 6270.62 kW, while the minimum heat transfer rate before and after the material replacement is 4573.61 kW and 4421.5 kW. Decreasing heat transfer rates indicate that the heat transfer rate in the T91 material is greater than the TP304H material. The difference in the value of heat transfer rates before and after material replacement is influenced by the thermal conductivity value of each material. From the point of view of thermal analysis, the replacement of T91 tube material into TP304H is not recommended.

Item Type: Thesis (Undergraduate)
Additional Information: RSM 621.183 Ter e
Uncontrolled Keywords: Reheater ; LMTD ; Laju Perpindahan Panas
Subjects: T Technology > TJ Mechanical engineering and machinery > TJ164 Power plants--Design and construction
T Technology > TJ Mechanical engineering and machinery > TJ263 Heat exchangers
Divisions: Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User: Mega Tertiasani
Date Deposited: 19 Feb 2019 03:35
Last Modified: 19 Feb 2019 03:35
URI: http://repository.its.ac.id/id/eprint/57791

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