Izzah, Rohmah Iftitah Sa'idatul (2024) Pemodelan Sebaran Penurunan Suhu Air Bahang pada Saluran Pendingin dan Strategi Mitigasi Dampak Polusi Termal: Studi Kasus PLTU Paiton. Masters thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Air laut pada sistem pendingin dengan prinsip siklus terbuka once through setelah dialirkan ke sistem penukar panas akan dikembalikan ke badan air laut melalui proses pendinginan di saluran pendingin, disebut air bahang. Air bahang memiliki karakteristik suhu air yang lebih tinggi dibandingkan suhu alami air laut. Tercatat adanya perubahan suhu perairan sekitar PLTU Paiton akibat buangan air bahang pada outlet water discharge mencapai 6,5°C. Menurut peraturan yang berlaku di Indonesia, suhu air bahang pada outlet water discharge seharusnya tidak lebih dari 2°C suhu alami air laut. Tujuan dari penelitian ini untuk memprediksikan pola penurunan suhu air bahang sepanjang saluran pendingin dan mengidentifikasi risiko lingkungan dan kesehatan akibat air bahang. Metode yang digunakan untuk memprediksikan pola penurunan suhu sepanjang saluran pendingin menggunakan pendekatan pemodelan CFD (Computational Fluid Dynamics) 3-dimensi dengan aplikasi Ansys Fluent 2022 RI. Pendekatan persamaan Reynold Average Navier-Stokes mengenai pergerakan fluida digunakan untuk menggambarkan pola penurunan suhu, model turbulensi k-epsilon dipilih untuk menggambarkan pengaruh turbulensi aliran terhadap perubahan suhu. Validasi hasil pemodelan dilakukan dengan membandingkan pengukuran data aktual lapangan suhu air yang mewakili sepanjang saluran pendingin. Upaya mitigasi pencemaran laut ditentukan berdasarkan hasil pemodelan CFD serta penilaian risiko lingkungan dan kesehatan yang disebabkan oleh air bahang. Penilaian risiko lingkungan dan kesehatan dilakukan dengan metode kualitatif. Hasil penelitian menunjukkan aliran air sepanjang saluran cenderung berada di sisi dinding kanan. Penurunan suhu air bahang menurut simulasi numerik dipengaruhi oleh nilai debit, semakin besar debit maka semakin besar penurunan suhu air bahang. Kinerja penurunan suhu air bahang meningkat ketika melewati terjunan (cascade aeration) di hilir saluran. Berdasarkan hasil penilaian risiko lingkungan dan kesehatan, terdapat 6 risiko sangat tinggi dan merupakan risiko tidak dapat diterima akibat adanya kenaikan suhu air laut. Upaya mitigasi yang perlu dilakukan antara lain: operasional debit air 20 – 25 m3/s dan suhu air bahang tidak melebihi 37°C, penambahan aerator berupa turbin PLTMH yang juga dapat berfungsi untuk energy recovery, dan kajian ulang penetapan batas suhu dan titik penaatannya.
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The condenser water discharge characterized by a higher water temperature than the natural temperature of seawater. There is a recorded change in the temperature of the waters around the Paiton power plant due to the water discharge at the outlet point reaching 6.5°C. According to applicable regulations in Indonesia, the outlet water discharge should not be more than 2°C of the natural temperature of sea water. The purpose of this study is to predict the pattern of water temperature reduction along the cooling channel and identify environmental and health risks due to condenser water discharge. The method used to predict temperature drop patterns along the cooling channels uses a 3-dimensional Computational Fluid Dynamics modeling approach with the Ansys Fluent 2022 RI software. The Reynold Average Navier-Stokes equation approach regarding fluid movement is used to describe the temperature decrease pattern, the k-epsilon turbulence model is chosen to describe the influence of flow turbulence on temperature changes. Validation of modeling results is carried out by comparing actual field data measurements of representative water temperatures along the cooling channel. Marine pollution mitigation efforts are determined based on the results of CFD modeling and assessments of environmental and health risks caused. Environmental and health risk assessments are carried out using qualitative methods. The results showed that water flow along the channel tends to be on the right wall. The decrease in the temperature of water according to the numerical simulation is influenced by debit, greater water flow causing greater decrease in water temperature. Cooling performance increases when it passes through the cascade aeration at the downstream. Based on the results of the environmental and health risk assessment, there are 6 very high and unacceptable risks due to rising of sea temperature. Mitigation efforts that need to be done include: operational water discharge of 20-25 m3/s and water temperature not exceeding 37°C, the addition of aerators in the form of MHP turbines that also used for energy recovery, and review of the determination of temperature limits and compliance points
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Air Bahang, CFD, Mitigasi Pencemaran Laut, Pemodelan, Saluran Pendingin, CFD, Cooling Channels, Marine Pollution Mitigation, Modeling, Thermal Wastewater. |
| Subjects: | T Technology > TD Environmental technology. Sanitary engineering T Technology > TD Environmental technology. Sanitary engineering > TD194.6 Environmental impact analysis T Technology > TD Environmental technology. Sanitary engineering > TD420 Water pollution T Technology > TD Environmental technology. Sanitary engineering > TD899 Waste control in special industries, plants, processes, etc T Technology > TD Environmental technology. Sanitary engineering > TD899.S68 Steam power plants |
| Divisions: | Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Environmental Engineering > 25101-(S2) Master Thesis |
| Depositing User: | Rohmah Iftitah Sa’idatul Izzah |
| Date Deposited: | 31 Jul 2024 03:35 |
| Last Modified: | 27 Aug 2024 07:26 |
| URI: | http://repository.its.ac.id/id/eprint/108884 |
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