Analisis Numerik Pengaruh Komposisi Tandan Kosong Kelapa Sawit dan Serbuk Gergaji Terhadap Proses Pembakaran Co-Firing Boiler PLTU 400 MW

Febisiana, Winie (2024) Analisis Numerik Pengaruh Komposisi Tandan Kosong Kelapa Sawit dan Serbuk Gergaji Terhadap Proses Pembakaran Co-Firing Boiler PLTU 400 MW. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Kebutuhan listrik yang meningkat setiap tahunnya tidak sebanding dengan total persediaan bahan bakar fosil di bumi. Untuk mengatasi keterbatasan bahan bakar fosil, beberapa PLTU sudah menerapkan co-firing dalam menghasilkan energi listrik. Co-firing merupakan proses pembakaran yang melibatkan biomassa sebagai pengganti parsial batubara bertujuan untuk mengurangi emisi gas buang. Dalam pengaplikasiannya, jenis biomassa dan rasio co-firing yang digunakan harus diperhatikan karena terdapat perbedaan komposisi bahan bakar antara biomassa dengan batubara sehingga perlu dilakukan peninjauan mengenai proses pembakaran yang terjadi dalam boiler seperti temperatur dan kecepatan pembakaran, emisi gas buang, dan kecenderungan terjadinya slagging dalam boiler. Penelitian ini menggunakan analisis Computational Fluid Dynamics (CFD) menggunakan software Ansys dan pemodelan 3D menggunakan software Solidwork. Boiler pada penelitian ini adalah boiler pada PLTU berkapasitas 400 MW dengan bahan bakar batubara yang memiliki HHV sebesar 4010,4 kcal/kg. Biomassa yang digunakan adalah tandan kosong kelapa sawit dan serbuk gergaji yang kemudian dilakukan pencampuran biomassa dengan rasio 1:1 antara tandan kosong kelapa sawit dengan serbuk gergaji. Campuran kedua biomassa divariasikan dengan batubara dengan rasio co-firing 5% dan 10% yang lalu divariasikan dengan excess air 16%, 17%, dan 18%. Berdasarkan hasil simulasi, penambahan persentase biomassa dan excess air dapat menurunkan temperatur pada daerah furnace exit. Pada co-firing 5% dan divariasikan dengan excess air 16%, 17%, dan 18% didapat nilai FEGT berturut-turut adalah 1192,04℃, 1190.52℃, dan 1185,28℃. Sedangkan pada co-firing 10% dengan variasi excess air 16%, 17%, dan 18% nilai FEGT berturut-turut adalah 1183,81℃, 1180,11℃, dan 1176,26℃. Kecepatan flue gas mengalami peningkatan seiring pertambahan persentase co-firing dan excess air. Hasil analisis kandungan O2 dalam gas buang mengalami penurunan sedangkan kandungan CO2 dalam gas buang mengalami kenaikan. Hal ini dapat menjadi indikasi bahwa pembakaran yang dilakukan sudah sempurna dan unburn karbon sedikit. Adapun nilai CO dan SO2 mengalami penurunan seiring dengan penambahan persentase biomassa dan excess air. Nilai CO dan SO2 terbesar ada pada pembakaran 100% batubara dengan nilai emisi berturut-turut adalah 1,07×10-8% dan 2,86×10-4%. Sedangkan nilai CO dan SO2 terkecil ada pada pembakaran co-firing 10% excess air 18% dengan nilai emisi berturut-turut adalah 2,26×10-11% dan 2,28×10-4%. Analisis slag dilakukan pada permukaan platen superheater A karena adanya kecenderungan terbentuk hot spots seiring penambahan persentase biomassa dan excess air. Potensi slag terbesar terjadi saat pembakaran co-firing 10% excess air 18%. Hal ini disebabkan temperatur permukaan platen superheater A lebih besar dibandingkan AFT biomassa. Dari hasil penelitian ini menunjukkan adanya potensi penggunaan co-firing dalam mengontrol temperatur dan mengurangi emisi. Akan tetapi, perlu diperhatikan rasio co-firing¬ ¬dalam kecenderungannya terhadap slagging
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The increasing electricity demand every year is not comparable to the total supply of fossil fuels on earth. To overcome the limitations of fossil fuels, several PLTUs have implemented co-firing in producing electrical energy. Co-firing is a combustion process involving biomass as a partial substitute for coal with the aim of reducing exhaust emissions. In its application, the type of biomass and the co-firing ratio used must be considered because there are differences in fuel composition between biomass and coal, so it is necessary to review the combustion process that occurs in the boiler such as temperature and combustion speed, exhaust emissions, and the tendency for slagging in the boiler. This study uses Computational Fluid Dynamics (CFD) analysis using Ansys software and 3D modeling using Solidwork software. The boiler in this study is a boiler at a 400 MW PLTU with coal fuel that has an HHV of 4010.4 kcal / kg. The biomass used is empty oil palm bunches and sawdust which is then mixed with biomass with a ratio of 1: 1 between empty oil palm bunches and sawdust. The mixture of both biomasses was varied with coal with a co-firing ratio of 5% and 10% which was then varied with excess air of 16%, 17%, and 18%. Based on the simulation results, the addition of biomass percentage and excess air can reduce the temperature in the furnace exit area. At 5% co-firing and varied with excess air of 16%, 17%, and 18%, the FEGT values ​​were respectively 1192.04℃, 1190.52℃, and 1185.28℃. While at 10% co-firing with excess air variations of 16%, 17%, and 18%, the FEGT values ​​were respectively 1183.81℃, 1180.11℃, and 1176.26℃. The flue gas velocity increased with the increase in the percentage of co-firing and excess air. The results of the analysis of O2 content in the exhaust gas decreased while the CO2 content in the exhaust gas increased. This can be an indication that the combustion is perfect and there is little unburn carbon. The CO and SO2 values ​​decreased along with the addition of biomass and excess air percentages. The largest CO and SO2 values ​​were in the combustion of 100% coal with emission values ​​of 1.07×10-8% and 2.86×10-4%, respectively. While the smallest CO and SO2 values ​​were in the combustion of 10% excess air 18% co-firing with emission values ​​of 2.26×10-11% and 2.28×10-4%, respectively. Slag analysis was carried out on the surface of the superheater A platen because of the tendency for hot spots to form along with the addition of biomass and excess air percentages. The greatest slag potential occurs during the combustion of 10% excess air 18% co-firing. This is because the surface temperature of the superheater A platen is greater than the AFT biomass. The results of this study indicate the potential for using co-firing to control temperature and reduce emissions. However, it is necessary to pay attention to the co-firing ratio in its tendency towards slagging

Item Type: Thesis (Other)
Uncontrolled Keywords: Co-firing, Excess Air, Slagging, Steam Power Plant Co-firing, Excess Air, Pembangkit Listrik Tenaga Uap, Slagging
Subjects: T Technology > TJ Mechanical engineering and machinery > TJ263.5 Boilers (general)
T Technology > TJ Mechanical engineering and machinery > TJ265.E23 Thermodynamics.
T Technology > TJ Mechanical engineering and machinery > TJ808 Renewable energy sources. Energy harvesting.
Divisions: Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User: Winie Febisiana
Date Deposited: 12 Aug 2024 01:42
Last Modified: 27 Aug 2024 06:28
URI: http://repository.its.ac.id/id/eprint/114338

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