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

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 > Industrial Engineering > 26201-(S1) Undergraduate Thesis
Depositing User:	Rajendra Pandu Daniswara
Date Deposited:	31 Jul 2026 01:53
Last Modified:	31 Jul 2026 01:53
URI:	http://repository.its.ac.id/id/eprint/139793

Available Versions of this Item

• 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) [Currently Displayed]
  • 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)

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