Analisis Termodinamika Pembentukan Scaling Pada Kondisi Kerja Scrubber, Demister, dan Turbin Pada 1st Stage Diaphraghm dan 1st Stage Rotor Pembangkit Listrik Tenaga Panas Bumi

Harmayanti, Afifah (2017) Analisis Termodinamika Pembentukan Scaling Pada Kondisi Kerja Scrubber, Demister, dan Turbin Pada 1st Stage Diaphraghm dan 1st Stage Rotor Pembangkit Listrik Tenaga Panas Bumi. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Kawasan panas bumi Gunung Salak adalah salah satu kawasan panas bumi di Indonesia yang mempunyai karakter uap water – dominated steam dengan konsentrasi non-condensable gas (NCG) yang tinggi dan komposisi steam purity yang rendah. Pada tahun 2004, salah satu unit pembangkit listrik di Gunung Salak ditingkatkan tanpa mengubah parameter kerja sistem. Upgrading diharapkan menghasilkan output sebesar 60.4 MWe, tetapi setelah setahun berjalan daya output tersebut turun menjadi 58.5 MWe. Hasil inspeksi menunjukkan hal tersebut terjadi akibat adanya scaling pada turbin dan komponen – komponen yang lain, termasuk demister. Demister merupakan komponen yang berperan menjaga kualitas uap agar tetap pada batas saturated steam. Oksigen diduga mempengaruhi pembentukan scaling tersebut. Setelah menggunakan non – oxygenated water untuk sistem steam wash, scaling dapat dikontrol.
Dalam penelitian ini akan dilakukan analisis termodinamika pengaruh tekanan parsial oksigen terhadap pembentukan scaling. Analisis tersebut disimulasikan menggunakan software HSC Chemistry 6.0 untuk mendapatkan diagram kestabilan fasa. Simulasi dilakukan pada scrubber, demister, dan turbin pada 1st stage diaphragm dan 1st stage rotor. Setelah dilakukan simulasi, akan dilakukan analisis perbandingan antara hasil simulasi dan pengujian deposit. Analisis akan difokuskan pada pembentukan oksida logam di demister karena hal tersebut merupakan salah satu scaling yang banyak ditemukan. Deposit diuji dengan metode SEM – EDX, ICP – OES, AAS dan XRD.
Dari penelitian ini didapat dari hasil perhitungan termodinamika, Fe2O3 setimbang pada tekanan parsial oksigen sebesar 1.03 x 〖10〗^(-42) bar. Temperatur kerja demister yaitu 164.3°C dan tekanan parsial oksigen yaitu 4.612 x10-5 bar (2005) dan 3.307 x 10-5 bar (2016), dapat menyebabkan reaksi pembentukan Fe2O3 hingga mencapai kesetimbangan.

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Gunung Salak is one of the potential geothermal area in Indonesia. The geothermal steam character is categorised as the water dominated steam with high non – condensable gas and low steam purity. In 2004, upgrading was made to one of the power plant located there. The upgrading was made without changing any operational parameter. It is expected to give a higher output, 60.4 Mwe. However after one year operating, the unit’s turbine experienced derating became 58.5 Mwe. Inspection results showed scale deposit on turbine and other essential equipment were the root factor of the problem. One of the equipment was demister. Demister is important to keep the quality of steam in saturated condition by separating water from the gas phase. Oxygen is expected to be responsible of the scale deposit. This was proofed by the ability to control scaling problem after using non – oxygenated water in their steam wash system.
In this research, thermodynamic analysis will be used to determine the effect of oxygen partial pressure to the formation of scale. The analysis is simulated using HSC Chemistry 6.0 to obtain phase stability diagram of the elements involved. The simulation is modelled in the pressure condition of scrubber, demister, 1st stage diaphragm and 1st stage rotor of turbine. After the diagram is obtained, comparison analysis between the simulation’s result and the real deposit found is carried out. The analysis is focused on the formation of ferrous oxide in demister as it is one of the most composition found in the deposit. The deposit is analysed using SEM – EDX, ICP – OES, AAS and XRD method.
The result shows that formation of Fe2O3 is in equilibrium condition with the oxygen partial pressure 1.03 x 〖10〗^(-42) bar. Operational temperature of demister, 164.3°C and oxygen partial pressure in the system 4.612 x10-5 bar (2005) and 3.307 x 10-5 bar (2016) can cause the reaction to form Fe2O3 until it reaches equilibrium state.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: oksigen; scaling; geothermal; derating; oxygen; scaling; geothermal; derating
Subjects: Q Science > QE Geology > QE571 Sedimentation and deposition. Sediment transport. Erosion.
T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK1318 Geothermal Power Plants
Divisions: Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User: AFIFAH HARMAYANTI
Date Deposited: 29 Mar 2017 04:00
Last Modified: 22 Dec 2017 01:08
URI: http://repository.its.ac.id/id/eprint/2194

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