Daniswara, Rajendra Pandu (2026) Studi Numerik dan Analitik Pengaruh Variasi Excess Air terhadap Distribusi Temperatur Flue Gas dan Final Reheater Tube pada Tangentially Fired Pulverized Coal Boiler 315 MW. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Keandalan operasional pulverized coal boiler sangat dipengaruhi oleh jumlah excess air pada proses pembakaran. Nilai excess air yang terlalu rendah menyebabkan pembakaran tidak sempurna dan berpotensi menimbulkan overheating pada komponen heating surface, sedangkan nilai yang terlalu tinggi menurunkan temperatur pembakaran dan meningkatkan stack loss. Penelitian ini bertujuan untuk mengetahui pengaruh variasi excess air terhadap karakteristik pembakaran, distribusi temperatur dan kecepatan flue gas, distribusi species flue gas, serta temperatur tube final reheater pada tangentially fired pulverized coal boiler 315 MW. Studi dilakukan secara numerik menggunakan ANSYS Fluent dengan pendekatan steady state, di mana proses pembakaran dimodelkan menggunakan species transport berbasis finite rate–eddy dissipation dan Discrete Phase Model (DPM), sedangkan komponen heating surface dimodelkan sebagai porous media dengan source term. Variasi excess air yang disimulasikan meliputi 0%, 10%, 16%, 20%, 30%, 40%, dan 50% di atas kebutuhan udara stoikiometri. Hasil simulasi berupa maximum temperature dan maximum velocity flue gas pada region final reheater selanjutnya digunakan sebagai input perhitungan analitik temperatur tube menggunakan korelasi Zukauskas untuk konveksi sisi luar dan korelasi Dittus–Boelter untuk konveksi sisi dalam. Hasil simulasi menunjukkan bahwa peningkatan excess air secara bertahap mengeliminasi fenomena delayed combustion dan melokalisasi proses char oxidation di lower combustion zone, disertai penurunan Furnace Exit Gas Temperature (FEGT) secara monoton dari sekitar 1118°C pada excess air 0% menjadi sekitar 982°C pada excess air 50%. Temperatur tube final reheater menunjukkan perubahan kurang signifikan dengan temperatur Tout stagnan di range 540 °C dan Tin di 538°C sehingga menunjukan bahwa perubahan excess air pada kasus ini tidak berdampak signifikan terhadap reliabilitas tube final reheater.
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Operational reliability of a pulverized coal boiler is significantly influenced by the amount of excess air in the combustion process. An excess air value that is too low causes incomplete combustion and has the potential to cause overheating of heating surface components, while a value that is too high lowers the combustion temperature and increases stack loss. This study aims to determine the effect of excess air variation on combustion characteristics, flue gas temperature and velocity distribution, flue gas species distribution, and final reheater tube temperature in a 315 MW tangentially fired pulverized coal boiler. The study was conducted numerically using ANSYS Fluent with a steady state approach, in which the combustion process was modeled using species transport based on the finite rate–eddy dissipation model and the Discrete Phase Model (DPM), while the heating surface components were modeled as porous media with a source term. The excess air variations simulated include 0%, 10%, 16%, 20%, 30%, 40%, and 50% above the stoichiometric air requirement. The simulation results in the form of maximum temperature and maximum velocity of the flue gas in the final reheater region were subsequently used as input for the analytical calculation of tube temperature using the Zukauskas correlation for outer-side convection and the Dittus–Boelter correlation for inner-side convection. The simulation results show that increasing excess air progressively eliminates the delayed combustion phenomenon and localizes the char oxidation process in the lower combustion zone, accompanied by a monotonic decrease in Furnace Exit Gas Temperature (FEGT) from approximately 1118°C at 0% excess air to approximately 982°C at 50% excess air. The final reheater tube temperature shows a less significant change, with Tout stagnant in the range of 540°C and Tin at 538°C, indicating that changes in excess air in this case do not have a significant impact on the reliability of the final reheater tube.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | CFD, Excess Air, Final Reheater, Pulverized Coal Boiler, Tangentially Fired CFD, Excess Air, Final Reheater, Pulverized Coal Boiler, Tangentially Fired.. |
| Subjects: | T Technology > TJ Mechanical engineering and machinery > TJ254.7 Combustion chambers T Technology > TJ Mechanical engineering and machinery > TJ263 Heat exchangers T Technology > TJ Mechanical engineering and machinery > TJ263.5 Boilers (general) T Technology > TJ Mechanical engineering and machinery > TJ265.E23 Thermodynamics. |
| Divisions: | Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis |
| Depositing User: | Rajendra Pandu Daniswara |
| Date Deposited: | 30 Jul 2026 01:44 |
| Last Modified: | 30 Jul 2026 01:44 |
| URI: | http://repository.its.ac.id/id/eprint/140030 |
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Studi Numerik dan Analitik Pengaruh Variasi Excess Air terhadap Distribusi Temperatur Flue Gas dan Final Reheater Tube pada Tangentially Fired Pulverized Coal Boiler 315 MW. (deposited 31 Jul 2026 01:53)
- Studi Numerik dan Analitik Pengaruh Variasi Excess Air terhadap Distribusi Temperatur Flue Gas dan Final Reheater Tube pada Tangentially Fired Pulverized Coal Boiler 315 MW. (deposited 30 Jul 2026 01:44) [Currently Displayed]
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