Simulasi Cycle Tempo Pengaruh Rasio Co-firing dan Variasi Biomassa Terhadap Performa PLTU Kapasitas 695,7 MW

Tambunan, Jhonstone Josua (2021) Simulasi Cycle Tempo Pengaruh Rasio Co-firing dan Variasi Biomassa Terhadap Performa PLTU Kapasitas 695,7 MW. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Co-firing atau co-combustion adalah pembakaran dua bahan bakar sekaligus untuk menghasilkan energi. Batu bara akan dicampur dengan biomassa, sehingga menghasilkan komposisi bahan bakar baru, dimana terjadi pengurangan persentase karbon dan sulfur dan persentase oksigen meningkat. Penerepan co-firing sangat marak karena bertujuan untuk meningkatkan bauran sumber energi bersih dan berkesinambungan pada pembangkit listrik batu bara. Namun, energi yang dihasilkan oleh biomassa relatif rendah, sehingga tidak mungkin menghasilkan efisiensi yang lebih tinggi jika dibandingkan dengan penggunaan batu bara seutuhnya. Selain itu, co-firing juga menyebabkan peningkatan pemakaian daya komponen pembangkit seperti fan dan mill. Maka dari itu, rasio antara batu bara dan biomassa harus diatur agar pembangkit tetap memberikan performa terbaik.
Metode yang dilakukan pada penelitian ini adalah studi numerik menggunakan software Cycle Tempo. Analisis sistem akan menggunakan data desain salah satu PLTU berkapastitas 695,7 MW. Simulasi pertama sekaligus baseline penelitian dijalankan dengan menggunakan 100% coal 5710 kCal/kg. Simulasi kedua dijalankan dengan melakukan variasi rasio co-firing dan variasi jenis biomassa. Pada simulasi kedua akan menggunakan coal 5100 kCal/kg. Peneliti memilih menggunakan coal 5100 kCal/kg karena batubara yang tersedia tidak lagi memiliki nilai kalor yang tinggi. Output generator pembangkit diatur tetap pada nilai 695,7 MW. Perbandingan antara primary air dan secondary air adalah sebesar 1 : 4,08. Kemudian, excess air sebesar 16,5%. Kondisi ini sesuai dengan kondisi existing pada pembangkit. Peneliti tidak mengubah parameter karena sesuai persyaratan pembangkit, tidak boleh ada perubahan parameter karena dapat mempengaruhi kinerja pembangkit.
Hasil simulasi co-firing menunjukkan kesesuaian dengan teori. Semakin besar rasio co-firing, maka performa pembangkit seperti kebutuhan batu bara, kebutuhan udara, efisiensi boiler, efisiensi pembangkit, konsumsi daya auxiliary equipment dan net plant heat rate akan berubah dari kondisi baseline. Co-firing wood pellet menunjukkan hasil yang terbaik diantara penggunaan jenis co-firing lainnya dalam segi kebutuhan batu bara, kebutuhan udara, dan konsumsi daya auxiliary equipment jika dibandingkan dengan kondisi baseline. Rata-rata peningkatan kebutuhan batubara, udara, dan daya auxiliary equipment masing-masing sebesar 10,52 kg/s, 1,17 kg/s dan 0,5 MW. Sementara itu, co-firing fine wood chip menunjukkan hasil terbaik dalam segi efisiensi boiler (rata-rata penurunan hanya 0,408%), efisiensi pembangkit (rata-rata penurunan hanya 0,198%), dan net plant heat rate (rata-rata peningkatan hanya 12,35 kCal/kWh). Kemudian, equipment existing pulverizer, primary air fan dan secondary air fan masih dapat beroperasi, sementara untuk induced draft fan tidak dapat beroperasi karena melebihi kapasitas.
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Co-firing or joint combustion is the burning of two fuels at once to produce energy. Coal will be mixed with biomass, resulting in new fuel composition, in which the percentage of carbon and sulfur reduced and the value of oxygen increased. The application of co-firing is very widespread because it aims to increase the combination of clean and sustainable energy sources in coal-fired power plants. However, the energy produced by biomass is relatively low, so it is not possible resulting higher efficiency when compared to the use of whole coal. In addition, co-firing also causes an increase in power consumption from generating components such as fans and mills. Therefore, the ratio between coal and biomass must be adjusted so that the power plant continues to provide the best performance.
The method applied in this research is a numerical study using Cycle Tempo software. The system analysis will use design data from one of the steam power plants in Indonesia with a capacity of 695,7 MW. The first simulation was carried out using 100% coal at 5710 kCal/kg meanwhile the second was run by varying the co-firing ratio and variations in the type of biomass. The second simulation will use coal 5100 kCal/kg. Researchers chose to use coal 5100 kCal/kg because the available coal no longer has a high calorific value. The generator output of the generator set to remain at the value of 695,7 MW. The ratio between primary and secondary water is 1:4,08. Then, the excess air is 16,5%. This condition is following the existing conditions at the generator. The researcher did not change the parameters because according to the requirements of the generator, there should be no changes in the parameters. After all, it could affect the performance of the generator.
The results of the co-firing simulation show conformity with the theory. The greater the co-firing ratio, the performance of the power plant like coal feed, air feed, boiler efficiency, power plant efficiency, auxiliary equipment power consumption and net plant heat rate will increase from the baseline condition. Co-firing wood pellets showed the best results among the use of other types of co-firing in terms of coal feed, air feed, and auxiliary equipment power consumption when compared to baseline conditions. The average increase in demand for coal, air, and auxiliary equipment is 10,52 kg/s, 1,17 kg/s and 0,5 MW, respectively. Meanwhile, fine wood chip co-firing showed the best results in terms of boiler efficiency (average decrease of only 0,408%), generator efficiency (average decrease of only 0,198%), and net plant heat rate (average increase of only 12,35 kCal/kWh). Then, the existing pulverizer equipment, primary air fan and forced draft fan can still operate, while the induced draft fan cannot operate because it exceeds capacity.

Item Type:	Thesis (Undergraduate)
Uncontrolled Keywords:	Co-firing, batu bara, biomassa, PLTU, efisiensi, pemakaian sendiri, NPHR, kebutuhan batu bara dan udara, Co-firing, steam power plant, coal, biomass, efficiency, auxiliary consumption, coal and total air feed
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ164 Power plants--Design and construction
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User:	Jhonstone Josua Tambunan
Date Deposited:	17 Aug 2021 13:31
Last Modified:	17 Aug 2021 13:31
URI:	http://repository.its.ac.id/id/eprint/87274

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