Ijazurrohman, Abdul Jabbar (2020) Analisis Kegagalan Waste Heat Boiler Tube. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Waste Heat Boiler secara umum memiliki beberapa komponen utama, dimana setiap komponen memiliki fungsi masing masing. Komponen utama pada Waste Heat Boiler khususnya pada fire tube boiler, antara lain seperti Flue gas inlet-outlet, fire tube, rear reversing chamber, inspenction doors, front reversing chamber, boiler body, smoke tubes, dan inspection holes. Dari beberapa bagian tersebut, bagian yang sering mengalami failure adalah bagian fire tube atau pipa api. Pipa yang digunakan pada WHB ini menggunakan material 13CrMo 4-5 yang merupakan baja karbon rendah. Pipa disebut mengalami kegagalan karena memiliki kondisi Tube Wall Loss >81%.
Analisis kegagalan dilakukan dengan beberapa langkah. Pertama yaitu melakukan sampling material dan pengumpulan data operasional boiler. Material yang sudah disampling selanjutnya di amati secara makroskopis untuk melihat tampilan visual dari tube. Selanjutnya material di potong dan dilakukan pengujian komposisi kimia untuk mengetahui komposisi kimia apa saja yang terdapat pada material. Lalu di lakukan pengujian metalografi untuk mengetahui struktur mikro dari material. Pengujian SEM - EDS perlu dilakukan juga untuk melihat adanya lapisan oksida dan unsur yang terkandung di permukaan luar dan dalam dari pipa. Yang terakhir yaitu analisa XRD untuk melihat senyawa yang terdapat pada kerak di permukan tube.
Pengamatan makroskopis dari WHB tube menunjukkan adanya penipisan pada permukaan luar akibat terkikir aliran steam. Hasil analisis komposisi kimia dan metalografi tidak menunjukkan adanya perbedaan dari standar. Namun, pengamatan SEM-EDS memperlihatkan adanya lapisan oksida di permukaan luar yang sangat tebal. Lapisan oksida ditemukan pada daerah yang tidak mengalami erosi parah. Hal ini dikarenakan pada bagian inlet WHB memiliki nilai heat flux yang sangat tinggi akibat terbentuknya aliran turbulent. Aliran turbulent terjadi karena adanya sudden enlargement oleh ujung ferrule ke pipa. Selain itu, beberapa unsur kimia juga terkandung di dalamnya dan dapat mempercepat terjadinya korosi (oksidasi). Dari hasil analisis XRD, ditemukan senyawa-senyawa hasil pembakaran batubara pada deposit kerak bagian luar. Dari analisis yang telah dilakukan, dapat disimpulkan bahwa penipisan tube terjadi karena efek gabungan dari korosi (oksidasi) akibat heatflux bagian dalam pipa dan erosi yang disebabkan oleh kecepatan aliran steam pada sisi luar.
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Waste Heat Boilers in general have several main components, where each component has its own function. The main components of the Waste Heat Boiler, especially in fire tube boilers, include Flue gas inlet-outlets, fire tubes, rear reversing chambers, inspection doors, front reversing chambers, boiler bodies, smoke tubes, and inspection holes. Of these parts, the part that often experiences failure is the fire tube or fire tube. The pipes used in this WHB use 13CrMo 4-5 material which is low carbon steel. The pipe is said to have failed because it has a Tube Wall Loss condition of> 81%.
The failure analysis is carried out in several steps. The first is conducting material sampling and collecting boiler operational data. The material that has been sampled is then examined macroscopically to see the visual appearance of the tube. Furthermore, the material is cut and chemical composition testing is carried out to determine the chemical composition of the material. Then do a metallographic test to determine the microstructure of the material. SEM - EDS testing also needs to be done to see the presence of oxide layers and elements contained on the outer and inner surface of the pipe. The last one is XRD analysis to see the compounds contained in the crust on the surface of the tube.
Macroscopic observations of the WHB tube show the presence of thinning on the outer surface due to clouding of the steam flow. The results of the analysis of chemical composition and metallography did not show any differences from the standard. However, SEM-EDS observations show a very thick oxide layer on the outer surface. The oxide layer is found in areas where there is no severe erosion. This is because the WHB inlet has a very high heat flux value due to the formation of turbulent flow. Turbulent flow occurs due to sudden enlargement by the end of the ferrule to the pipe. In addition, several chemical elements are also contained in it and can accelerate corrosion (oxidation). From the results of XRD analysis, it was found that coal combustion compounds were found in the outer crust deposits. From the analysis that has been carried out, it can be concluded that tube thinning occurs due to the combined effect of corrosion (oxidation) due to heatflux on the inside of the pipe and erosion caused by the velocity of steam flow on the outside.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | Waste Heat Boiler, Failure, Tube Wall Loss, Turbulent, Heat Flux, Korosi, Oksidasi, Erosi, Waste Heat Boiler, Failure, Tube Wall Loss, Turbulent, Heat Flux, Corrosion, Oxidation, Erosion |
| Subjects: | T Technology > TJ Mechanical engineering and machinery > TJ263.5 Boilers (general) |
| Divisions: | Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis |
| Depositing User: | Abdul Jabbar Ijazurrohman |
| Date Deposited: | 23 Aug 2020 06:27 |
| Last Modified: | 04 Jul 2023 16:18 |
| URI: | http://repository.its.ac.id/id/eprint/80404 |
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