Analisis Termal Dan Optimasi Pltu Berbahan Bakar Low Rank Coal Dengan Variasi Flue Gas Recirculation

Darmadi, I Gede (2020) Analisis Termal Dan Optimasi Pltu Berbahan Bakar Low Rank Coal Dengan Variasi Flue Gas Recirculation. Masters thesis, Institut Teknologo Sepuluh Nopember.

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Abstract

PLTU Unit 1-4 Suralaya (4 x 400 MW) merupakan coal fired power plant dengan subcritical-boiler tipe radiant tower yang dilengkapi dengan sistem pemanasan ulang (reheat) serta desain bahan bakar menggunakan medium rank coal. Terdapat beberapa cara untuk meningkatkan kinerja coal fired power plant salah satunya adalah flue gas recirculation (FGR) system. Sistem ini dapat meningkatkan kinerja pembangkit terutama saat beban dibawah maximum continuous rating (MCR). Sistem FGR meningkatkan laju aliran gas buang yang memasuki superheater dan reheater untuk meningkatkan perpindahan panas secara konveksi. Sistem FGR ini sudah terpasang pada boiler Unit 1-4 Suralaya tetapi tidak difungsikan secara menerus. Penelitian lebih lanjut diperlukan untuk mengevaluasi efek FGR pada beberapa variasi beban dan perubahan bahan bakar dari medium rank coal (MRC) ke low rank coal (LRC) terhadap unjuk kerja PLTU. Penelitian ini didasarkan pada analisis termodinamika dan dimodelkan melalui perangkat lunak Cycle-Tempo 5.0. Operasi FGR dinyatakan dalam 3 (tiga) variasi operasi FGR, yaitu model pertama tanpa FGR, model kedua menggunakan FGR yang dicerat dari outlet economizer dan model ketiga menggunakan FGR yang dicerat dari outlet reheater. Jumlah aliran massa FGR divariasikan 5-30% dari total flue gas. Variasi penggunaan batubara adalah sesuai desain medium rank coal (5242 kCal/kg) dan low rank coal (4280 kCal/kg). Variasi pembebanan untuk pemakaian kedua jenis bahan bakar tersebut adalah 100%, 75% dan 65% MCR. Setelah model dievaluasi dan divalidasi dengan desain heat balance serta desain boiler Unit 1-4, dilanjutkan dengan mengalirkan FGR ke dalam boiler melalui 3 (tiga) variasi aliran, yaitu gas furnace (GF), gas tempering (GT) dan kombinasi keduanya. Rasio kombinasi antara GF dan GT adalah 10-90% GF dan 10-90% GT. Variasi optimum pengoperasian FGR untuk mendapatkan efisiensi optimal dengan risiko rendah overheating dan slagging pada pengoperasian batubara low rank coal diperoleh pada simulasi pada model kedua dengan FGR 30% sebagai berikut, batubara 5242 kCal/kg (MRC) pada beban 100% MCR dengan distribusi 60% GF dan 40% GT efisiensi 42,26%, pada beban 75% MCR dengan distribusi 30% GF dan 70% GT efisiensi 41,86%, pada beban 65% MCR dengan distribusi 30% GF dan 70% GT efisiensi 41,31%. Batubara 4280 kCal/kg (LCR) pada beban 100% MCR dengan distribusi 80% GF dan 20% GT efisiensi 38.83%, pada beban 75% MCR dengan distribusi 50% GF dan 50% GT efisiensi 36,10%, pada beban 65% MCR dengan distribusi 20% GF dan 70% GT efisiensi 34,32%.
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Suralaya Unit 1-4 (4 x 400 MW) is a coal fired power plant with a radiant tower type subcritical boiler equipped with a reheat system and fuel design using medium rank coal. There are several measures to improve the performance of coal
fired power plants, one of the measures is the flue gas recirculation (FGR) system. This system can improve the performance of plants, especially at lower loads than maximum continuous rating (MCR). The FGR system increases the rate of exhaust gas flow entering the superheater and reheater to increase convection heat transfer. This FGR system is installed on Suralaya Unit 1-4 boilers. Further study is needed to evaluate the effect of FGR on various load variations and fuel changes from medium rank coal (MRC) to low rank coal (LRC). This study is based on thermodynamic analysis and is modeled through Cycle-Tempo 5.0 software. FGR operation with three variations, the first model without FGR, the second model with FGR which flue gas extraction from the outlet economizer and the third model with FGR which flue gas extraction from the reheater outlet. Variation flow rate FGR from 5-30% from total flue gas. The variations operation of coal is according to the design of medium rank coal (5242 kCal / kg) and proposed low rank coal (4200 kCal / kg). The Load variation of both types of fuel is 100%, 75% and 65% MCR. After the model is evaluated and validated with the heat balance design and boiler unit 1-4 design, it is continued by flowing the FGR into the boiler through 3 (three) flow variations, gas furnace (GF), tempering gas (GT) and combination of both. Combination of GF and GT are 10 90% GF and 10-90% GT. The optimum variation of FGR operation to get optimum efficiency with a low risk of overheating and slagging is obtained in the simulation on the second model for LRC operation with 30% ratio of FGR. MRC of 5242 kCal/kg at loads 100% MCR with combination direction 60% GF and 40% GT efficiency 42.26%, at load 75% MCR with combination direction 30% GF and 70% GT efficiency 41.86%, at load 65% MCR with combination direction 30% GF and 70% GT efficiency 41.31%. LRC of 4280 kCal/kg at loads 100% MCR with combination direction 80% GF and 20% GT efficiency 38.83%, at load 75% MCR with combination direction 50% GF and 50% GT efficiency 36.10%, at load 65% MCR with combination direction 30% GF and 70% GT efficiency 34.32%.

Item Type:	Thesis (Masters)
Additional Information:	RTM 621.402 5 Dar a-1
Uncontrolled Keywords:	Flue Gas Recirculation, Coal Fired Power Plant, Low Rank Coal, Cycle-Tempo, FGR Ratio
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ778 Gas turbines
Divisions:	Faculty of Industrial Technology > Mechanical Engineering > 21101-(S2) Master Thesis
Depositing User:	Darmadi Darmadi
Date Deposited:	05 Mar 2025 04:21
Last Modified:	05 Mar 2025 04:21
URI:	http://repository.its.ac.id/id/eprint/75316

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