Analisa Kegagalan Material Pada Air Cap Nozzle Circulating Fluidized BED (CFB) Boiler

Bachtiar, Muhammad Yusuf (2020) Analisa Kegagalan Material Pada Air Cap Nozzle Circulating Fluidized BED (CFB) Boiler. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pembangkit listrik tenaga uap adalah pembangkit listrik dimana generator listrik digerakkan uap. Air dipanaskan lalu berubah menjadi uap dan memutar turbin uap yang menggerakkan generator listrik. Setelah melewati turbin, uap dikondensasikan dalam kondensor. Nozzle merupakan salah satu komponen penting pada pembangkit listrik tenaga uap. Nozzle terletak dibagian bawah furnace yang berfungsi untuk mengarahkan aliran dimana sering terjadi kegagalan. Kegagalan umumnya terjadi karena adanya penyumbatan pada bagian air cap nozzle dan pengikisan pada permukaan air cap nozzle. Air cap nozzle menggunakan material stainless steel type 316L dimana dengan kandungan campuran 16-18% krom, 10-14% nikel, serta mangan dan nitrogen. Pada penelitian dilakukan tahap simulasi, pengujian, dan analisis. Pada tahap simulasi, dilakukan simulasi pada komponen air cap nozzle menggunakan ANSYS untuk mengetahui pengaruh kecepatan fluida dengan tekanan yang terjadi pada air cap nozzle ketika boiler diaplikasikan. Kemudian terdapat tahap pengujian berupa pengamatan makro dan mikro dari air cap nozzle. Adapun pengujian dilakukan dengan pengamatan spectrometer, uji metalografi, uji micro-hardness, dan scanning electron microscopy (SEM). Terakhir ialah dilakukan analisa kegagalan nozzle ini berdasarkan pengamatan yang telah dilakukan. Dari hasil simulasi dan pengujian, failure yang terjadi pada air cap nozzle berupa erosi dan retak. Erosi disebabkan aliran fluida membawa zat pengotor (batubara & limestone) yang mengalir pada air cap nozzle dan skin friction mengakibatkan penipisan pada permukaan. Keretakan terjadi karena adanya tumbukan bahan bakar dengan ukuran besar yang mengenai permukaan air cap nozzle. Dari pengujian spectrometer dan SEM didapatkan komposisi kimia yang berbeda pada material stainless steel 316L dengan komposisi kimia standar untuk Stainless steel 316L. Pada pengamatan metalografi terdapat fasa austenite,fasa ferritic dan karbida. Pada pengujian hardness didapatkan nilai kekerasan lebih tinggi daripada kekerasan material standar dikarenakan adanya karbida pada material benda uji. ============================================================ A steam power plant is a the electric generator driven by steam. The heated water turns into steam and spins a steam turbine that drives an electric generator. After passing through the turbine, the steam is condensed in the condenser. The nozzle is one of the important components in a steam power plant. The nozzle is located at the bottom of the furnace which functions to direct the flow where failure often occurs. Failure generally occurs because of a blockage in the part water nozzle cap and scrape on the water cap nozzle surface. Air cap nozzle using the material of stainless steel type 316L where a mixture contents of 16-18% chromium, 10-14 % nickel, manganese, and nitrogen. In this study there are three stages; simulation, testing, and analysis. At the stage of the simulation, simulations on components water nozzle cap using ANSYS was generated to find the effect of the speed of the fluid with the pressure which occurs in water cap nozzle when the boiler is operated. Then there is a testing phase in the form of macro and micro observations of the nozzle cap water was performed. The testing is done by observation spectrometer, test metallography, test micro-hardness, and scanning electron microscopy (SEM). Finally, the nozzle failure analysis is carried out based on the observations that have been made. From the results of the study, the failure was occured in the form of erosion and cracks. Erosion caused by the fluid flow carrying the substance impurities (coal and limestone) that flows in the water nozzle cap and the skin friction, causing the surface depletion. Cracks occurred due to the impact between the fuel with size large and the surface water nozzle cap. From spectrometer and SEM testing, the composition of chemicals that diffrent the material of stainless steel 316L with Stainles steel 316L. In metallographic observations, there are austenite, ferritic, and carbide phases. From the hardness testing, the value of hardness is higher than the hardness of material standard because of the carbide occurred in the material object test.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: nozzle,CFB, struktur mikro, stainless steel type 316L nozzle , CFB , microstructure, stainless steel type 316L
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA169.5 Failure analysis
Divisions: Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User: Muhammad Yusuf Bachtiar
Date Deposited: 24 Aug 2020 03:32
Last Modified: 24 Aug 2020 03:32
URI: http://repository.its.ac.id/id/eprint/80351

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