., Andri (2018) Analisa Pengaruh Kecepatan Forced Cooling Terhadap Mikrostruktur, Kekuatan Tarik Dan Kekerasan Tube Superheater Pulverized Coal Boiler. Masters thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Durasi down time untuk outage terencana maupun tidak terencana berpotensi menurunkan tingkat availability pembangkitan. Oleh karena itu durasi down time diharapkan dilakukan dalam waktu sesingkat mungkin. Berdasarkan data Pareto Loss Output pada PLTU FTP–1 tahun 2016 dan 2017 menunjukkan kebocoran boiler masih menjadi sepuluh besar gangguan yang sering terjadi. Proses pendinginan dalam rangkaian kegiatan perbaikan boiler memegang peranan penting terkait durasi down time. Selain natural cooling salah satu upaya menurunkan down time adalah dengan melakukan pendinginan forced cooling boiler.
Penelitian ini bertujuan untuk menganalisa pengaruh forced cooling terhadap struktur mikro, kekuatan tarik dan kekerasan dari material superheater. Penelitian ini dimulai dengan melakukan permodelan 3D dan simulasi pendinginan boiler menggunakan software CFD. Dari hasil simulasi didapatkan laju penurunan temperatur tube superheater. Kemudian dilanjutkan dengan eksperimen pemanasan material tube superheater T91 pada Ash furnace laboratorium sampai dengan suhu 540 oC dan didinginkan sesuai dengan laju penurunan temperatur hasil simulasi software CFD pada ash furnace laboratorium dengan temperatur terkontrol. Pengujian yang dilaksanakan adalah pengujian struktur mikro, kekuatan tarik dan kekerasan.
Kecepatan pendinginan boiler berpengaruh pada struktur mikro yang terbentuk. Pada pendinginan boiler dengan metode natural cooling diperoleh struktur mikro martesite dan ferrite. Pada pendinginan boiler dengan metode forced cooling menggunakan FD Fan kapasitas 20% dan 40 % diperoleh struktur mikro martensite dan pearlite. Kekerasan rata rata yang dihasilkan dengan natural cooling adalah 202,7 HV, forced cooling dengan FD Fan kapasitas 20% dan 40% adalah 204,1 HV dan 199,8 HV. Hasil pengujian kekuatan tarik didapatkan hasil untuk natural cooling adalah 660, 28 MPa dan forced cooling dengan FD Fan kapasitas 20% dan 40% adalah 635,18 MPa dan 646,84 MPa. Selain berpengaruh pada sifat mekanik, variasi pendinginan boiler juga berpengaruh terhadap penurunan nilai elongasinya, dari 23,84 % untuk natural cooling dan untuk forced cooling adalah 21,61 dan 20,92%
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The duration of down time for planned and unplanned outages have potential impact to decrease the availability of power generation. Therefore, the duration of downtime is expected to be as short as possible. According to Pareto Loss Output Data of FTP-1 Power Plant at 2016 - 2017, boiler leakage still be the top ten problems that often happens. Cooling process in boiler maintenance play an important role related to downtime duration. In addition to natural cooling, boiler forced cooling can be used to minimize the downtime.
This research aims to analyze the effect of forced cooling on micro structure, tensile strength and hardness of superheater tube. This research is conducted by modeling and simulation the rate of boiler cooling using CFD software. Cooling time simulation obtained from the modeling result. The superheater material was heated using laboratory Ash furnace up to 540°C and cooled using temperature controlled afterwards, according to the modeling results. Furthermore, microstructural analysis, tensile strength and hardness testing were carried out.
The result shows that the cooling rate is increase with the use of forced cooling than natural cooling. Cooling rate affects the microstructure formed. At natural cooling method obtained ferrite and Pearlite microstructure with grain size 3,37 μm. At forced cooling method using FD Fan capacity 20% and 40% obtained ferrite and Pearlite micro structure with grain size 3,37 μm and 4,22 μm. The average hardness on natural cooling methode were 202.7 HV, forced cooling with FD Fan capacity of 20% and 40% were 204.1 HV and 199.8 HV. Tensile strength test results for natural cooling are 660, 28 MPa and forced cooling with FD Fan capacity of 20% and 40% are 635,18 MPa and 646,84 MPa. cooling boiler methode also affects on percentage elongation value, Increase cooling rate cause decreasing of percentage elongation value, from 23.84% for natural cooling and for forced cooling is 21.61 and 20.92%
| Item Type: | Thesis (Masters) |
|---|---|
| Additional Information: | RTM 621.194 And a |
| Uncontrolled Keywords: | Forced cooling, Microstructure, Hardness, Tensile Stength, Forced cooling, struktur mikro, kekuatan tarik, kekerasan |
| Subjects: | T Technology > TJ Mechanical engineering and machinery > TJ263 Heat exchangers |
| Divisions: | Faculty of Industrial Technology > Mechanical Engineering > 21101-(S2) Master Thesis |
| Depositing User: | andri andri |
| Date Deposited: | 03 Dec 2018 08:58 |
| Last Modified: | 29 Sep 2020 02:35 |
| URI: | http://repository.its.ac.id/id/eprint/59639 |
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