Perancangan Plate Heat Exchanger Tipe Chevron Sebagai Pendingin Air Jet Ejector Pada Sistem Vakum Kondensor PLTU 25 MW

Prasetyo, Wahyu (2026) Perancangan Plate Heat Exchanger Tipe Chevron Sebagai Pendingin Air Jet Ejector Pada Sistem Vakum Kondensor PLTU 25 MW. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Kevakuman kondensor merupakan aspek penting dalam meningkatkan efisiensi PLTU, terutama pada unit berkapasitas 25 MW yang bergantung pada performa water jet ejector. Saat ini, unit mengalami penurunan vakum yang hanya mencapai -51 kPa. Kondisi ini disebabkan oleh tingginya motive flow temperature (MFT) yang mencapai 55,6 °C, sehingga melemahkan momentum hisap terhadap non-condensable gas. Oleh karena itu, dirancang sebuah plate heat exchanger guna menurunkan temperatur MFT ke suhu ideal 40°C. Perancangan dilakukan berdasarkan parameter operasi aktual, temperatur masuk fluida dingin 35 °C, fluida panas 75 °C, flowrate fluida panas 200 m^3/h, dengan process water sebagai fluida panas dan sea water sebagai fluida dingin. Untuk mendapatkan desain yang optimal, penelitian ini memvariasikan parameter sudut chevron pelat pada 30°, 45°, dan 60° serta flowrate fluida dingin pada rentang 200 hingga 350 m^3/h. Metode perancangan dilakukan menggunakan pendekatan Log Mean Temperature Difference untuk mengetahui kebutuhan heat transfer area. Hasil perhitungan diperoleh secara analitis lalu divalidasi dengan software Aspen Exchanger Design and Rating. Hasil perancangan menunjukkan konfigurasi sudut chevron 60° merupakan desain yang paling optimum karena kebutuhan beban 8004 kW dapat dicapai secara efisien hanya dengan heat transfer area {180\ m}^2 pada flowrate fluida 239 m^3/h. Berdasarkan evaluasi nozzle loading dan kecepatan aliran pada port menggunakan standard ISO 15547:2000, kebutuhan heat transfer area tersebut dibagi ke dalam 3 unit Plate Heat Exchanger dengan susunan konfigurasi paralel, sehingga dalam satu unit PHE terdapat 123 lembar pelat. Dengan desain ini, pressure drop yang dihasilkan tetap aman dibawah batas pompa suplai yakni sisi fluida panas sebesar 0,23 bar dan pada fluida dingin sebesar 0,34 bar. Dengan efektivitas perpindahan panas sebesar 89%, desain ini mampu mendinginkan fluida panas secara konsisten hingga mencapai suhu 39,5 °C.
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Condenser vacuum is a crucial aspect in improving the efficiency of a steam power plant (PLTU), particularly in a 25 MW capacity unit that relies on water jet ejector performance. Currently, the unit is experiencing a decrease in vacuum, reaching only -51 kPa. This condition is caused by a high motive flow temperature (MFT) of 55.6 °C, which weakens the suction momentum for non-condensable gases. Therefore, a plate heat exchanger is designed to lower the MFT to an ideal temperature of 40 °C. The design is based on actual operating parameters: a cold fluid inlet temperature of 35 °C, a hot fluid inlet temperature of 75 °C, and a hot fluid flow rate of 200 m^3/h, utilizing process water as the hot fluid and sea water as the cold fluid. To obtain the optimal design, this study varies the plate chevron angle parameters at 30°, 45°, and 60°, as well as the cold fluid flow rate in the range of 200 to 350 m^3/h. The design method employs the Log Mean Temperature Difference approach to determine the required heat transfer area. The calculation results are obtained analytically and then validated using the Aspen Exchanger Design and Rating software. The design results indicate that the 60° chevron angle configuration is the most optimum design because the 8004 kW heat load requirement can be achieved efficiently with a heat transfer area of only {180\ m}^2 at a cold fluid flow rate of 239 m^3/h. Based on the evaluation of nozzle loading and port flow velocity using the ISO 15547:2000 standard, the required heat transfer area is divided into 3 Plate Heat Exchanger units arranged in a parallel configuration, resulting in 123 plates per PHE unit. With this design, the resulting pressure drop remains safely below the supply pump limits, specifically 0.23 bar on the hot fluid side and 0.34 bar on the cold fluid side. With a heat transfer effectiveness of 89%, this design is capable of consistently cooling the hot fluid to reach a temperature of 39.5 °C.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Plate Heat Exchanger, Water Jet Ejector, Sudut Chevron, LMTD, NTU–Effectiveness, Aspen Exchanger Design and Rating
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ263 Heat exchangers
Divisions:	Faculty of Vocational > Mechanical Industrial Engineering (D4)
Depositing User:	Wahyu Prasetyo
Date Deposited:	09 Jul 2026 05:57
Last Modified:	09 Jul 2026 05:57
URI:	http://repository.its.ac.id/id/eprint/134563

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