Studi Numerik Pengaruh PA/SA Rasio Dan Kualitas Batubara Terhadap Karakteristik Pembakaran Dan Aliran Pada PLTU CFB Labuhan Angin

Syahrial, Rahmad (2026) Studi Numerik Pengaruh PA/SA Rasio Dan Kualitas Batubara Terhadap Karakteristik Pembakaran Dan Aliran Pada PLTU CFB Labuhan Angin. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Peningkatan kebutuhan energi listrik nasional menuntut optimalisasi kinerja pembangkit listrik tenaga uap (PLTU) berbahan bakar batubara. Pada boiler Circulating Fluidized Bed (CFB), distribusi udara pembakaran antara udara primer dan udara sekunder merupakan parameter penting yang memengaruhi karakteristik aliran, performa pembakaran, efisiensi energi, dan emisi gas buang. Selain itu, variasi kualitas batubara menyebabkan perbedaan karakteristik pembakaran sehingga diperlukan pengaturan rasio PA/SA yang sesuai dengan jenis bahan bakar yang digunakan. Penelitian ini bertujuan menganalisis pengaruh variasi rasio PA/SA dan kualitas batubara terhadap karakteristik aliran dan pembakaran pada boiler CFB PLTU Labuhan Angin. Analisis dilakukan menggunakan metode Computational Fluid Dynamics (CFD) dengan perangkat lunak Ansys Fluent 2024 R2 pada boiler CFB berkapasitas 2 × 115 MW. Simulasi dilakukan menggunakan dua jenis batubara, yaitu Low Rank Coal (LRC) dan Medium Rank Coal (MRC), dengan variasi rasio PA/SA sebesar 40/60, 50/50, 60/40, dan 70/30. Parameter yang dianalisis meliputi distribusi fraksi volume pasir, kecepatan partikel pasir, distribusi temperatur, serta distribusi gas buang CO₂, O₂, dan NOx. Hasil simulasi menunjukkan bahwa peningkatan proporsi udara primer meningkatkan kecepatan partikel pasir dan laju sirkulasi padatan, yang mengindikasikan meningkatnya potensi erosi pada area lower furnace, wingwall, dan cyclone. Rasio PA/SA 40/60 dan 50/50 menghasilkan distribusi temperatur yang lebih homogen dibandingkan rasio 60/40 dan 70/30. Batubara MRC menghasilkan temperatur furnace yang lebih tinggi dan lebih stabil dibandingkan LRC, namun juga menghasilkan emisi NOx yang lebih tinggi. Variasi PA/SA 40/60 dan 50/50 menghasilkan fraksi massa CO₂ tertinggi sekitar 0,16–0,17 yang mengindikasikan proses oksidasi karbon yang lebih sempurna, sedangkan peningkatan rasio udara primer menyebabkan konsentrasi O₂ dan NOx cenderung meningkat. Rasio PA/SA 50/50 memberikan performa pembakaran terbaik karena mampu menghasilkan distribusi temperatur yang relatif homogen, konversi karbon yang tinggi, pemanfaatan oksigen yang baik, serta emisi NOx yang masih terkendali. Hasil penelitian ini dapat digunakan sebagai dasar pengaturan distribusi udara pembakaran yang adaptif terhadap variasi kualitas batubara pada boiler CFB.
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The increasing national electricity demand necessitates the optimization of coal-fired power plant performance. In a Circulating Fluidized Bed (CFB) boiler, the distribution of combustion air between primary air and secondary air is a critical operational parameter that influences flow characteristics, combustion performance, energy efficiency, and flue gas emissions. In addition, variations in coal quality result in different combustion characteristics, requiring appropriate adjustment of the Primary Air/Secondary Air (PA/SA) ratio according to the fuel type being utilized. This study aims to analyze the effects of PA/SA ratio variations and coal quality on the flow and combustion characteristics of the CFB boiler at the Labuhan Angin Coal-Fired Power Plant. The analysis was conducted using Computational Fluid Dynamics (CFD) simulations with Ansys Fluent 2024 R2 on a 2 × 115 MW CFB boiler. Two coal types were investigated, namely Low Rank Coal (LRC) and Medium Rank Coal (MRC), with PA/SA ratios of 40/60, 50/50, 60/40, and 70/30. The evaluated parameters included sand volume fraction distribution, sand particle velocity, temperature distribution, and the distribution of CO₂, O₂, and NOx in the flue gas. The simulation results indicate that increasing the proportion of primary air enhances sand particle velocity and solids circulation rate, suggesting a higher erosion potential in the lower furnace, wingwall, and cyclone regions. PA/SA ratios of 40/60 and 50/50 produced more uniform temperature distributions compared to ratios of 60/40 and 70/30. MRC generated higher and more stable furnace temperatures than LRC; however, it also resulted in higher NOx emissions. The 40/60 and 50/50 PA/SA ratios yielded the highest CO₂ mass fractions, approximately 0.16–0.17, indicating more complete carbon oxidation. Meanwhile, increasing the primary air ratio led to higher O₂ and NOx concentrations. The 50/50 PA/SA ratio provided the best overall combustion performance, achieving a relatively uniform temperature distribution, high carbon conversion, effective oxygen utilization, and controlled NOx emissions. The findings of this study can serve as a basis for developing adaptive combustion air distribution strategies in CFB boilers operating with varying coal qualities.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Boiler CFB, Computational Fluid Dynamics (CFD), Primary Air, Secondary Air, Rasio PA/SA, Kualitas Batubara, Emisi NOx, CFB Boiler, Computational Fluid Dynamics (CFD), Primary Air, Secondary Air, PA/SA Ratio, Coal Quality, NOx Emissions.
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ254.7 Combustion chambers
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21101-(S2) Master Thesis
Depositing User:	Rahmad Syahrial
Date Deposited:	31 Jul 2026 02:51
Last Modified:	31 Jul 2026 02:51
URI:	http://repository.its.ac.id/id/eprint/138785

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