Parinussa, Renaldo Maxillion (2018) Thermal Re-Design High Pressure Heater #3 (Beban 15 MW) PLTU dengan Variasi Kecepatan Feedwater dan Baffle Spacing menggunakan Analisa Termodinamika - Perpindahan Panas dan Software Aspen Fran. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
High Pressure Heater (HPH) merupakan shell and tube heat exchanger yang berfungsi untuk menaikkan temperature feedwater sebelum memasuki boiler. Dalam PLTU Pangkalan Susu Unit 2, HPH #3 adalah HPH yang terletak setelah Boiler Feedwater Pump (BFP). Sisi shell HPH #3 dialiri oleh dua jenis fluida panas. Pertama, ekstraksi uap dari Intermediate Pressure (IP) Turbine yang sebelumnya didinginkan terlebih dahulu di steam cooler. Kedua, drain water dari HPH #2 yang sebelumnya didinginkan terlebih dahulu di drain cooler. Feedwater mengalir pada sisi tube sebagai fluida yang dipanaskan. Penggunaan steam cooler dan drain cooler ternyata menimbulkan beberapa dampak negative bagi kelangsungan operasi PLTU dari segi reliability. Oleh karena itu, steam cooler dan drain cooler dihilangkan dari sistem PLTU sehingga ekstraksi uap dari IP Turbine dan drain water dari HPH #2 langsung memasuki HPH #3 tanpa melalui proses pendinginan. Hal ini mendasari proses redesign HPH #3 dengan variasi kecepatan feedwater dan baffle spacing dengan analisa termodinamika– perpindahan panas dan checking angka keamanan dengan software ASPEN Fran.
Proses analisa diawali dengan menghitung Heat Load dan ΔTlm pada HPH #3 yang baru. Setelah itu dilakukan perhitungan overall heat transfer coefficient yang terjadi pada masing-masing zona perpindahan panas (desuperheating zone dan condensing zone) dan dilanjutkan dengan perhitungan Heat Transfer Area. Kemudian dilakukan proses perhitungan pressure drop di sisi tube dan shell. Geometri dan proses hasil perhitungan akan menjadi input simulasi software ASPEN Fran untuk mengetahui luas perpindahan panas yang dibutuhkan serta pressure drop sisi tube dan shell. Hasil antara perhitungan dan software akan dibandingkan dan dianalisa.
Variasi kecepatan yang digunakan adalah 0,5m/s ; 1m/s ; 1,5m/s dan 2m/s. Variasi baffle spacing yang digunakan adalah (desuperheating/condensing) 0,3m/0,66m ; 0,35m/0,83m ; 0,4m/0,99m ; 0,45m/1,16m. Dari perhitungan dan simulasi, dapat disimpulkan bahwa semakin cepat aliran fluida di sisi tube, nilai overall heat transfer coefficient akan semakin tinggi sehingga luas perpindahan panas yang dibutuhkan semakin kecil, namun pressure drop di sisi tube juga meningkat secara eksponensial. Semakin lebar baffle spacing, overall heat transfer semakin rendah sehingga luas perpindahan panas yang dibutuhkan semakin besar. Berdasarkan analisa dari masing-masing variasi, diperoleh bahwa HPH #3 optimal berada pada kecepatan feedwater 1 m/s dengan baffle spacing (desuperheating/condensing) 0,3m/0,83m.
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High Pressure Heater (HPH) is a shell and tube heat exchanger which have a main function to increase the feedwater temperature before it flow into the boiler. In 2nd unit of Pangkalan Susu Power Plant, HPH #3 is located after Boiler Feedwater Pump (BFP). Shell side of HPH #3 is flowed by two different fluid. The first one is steam extraction from Intermediate Pressure (IP) turbine. Before enter HPH #3, the steam is being cooled by another heat exchanger called steam cooler. The second fluid is drain water from HPH #2 which is cooled by drain cooler before entering HPH #3. Feedwater is flowing inside the tube side of HPH #3. In the actual condition, steam cooler and drain cooler frequently give a bad impact to the system, especially in reliability aspect. That is the reason why steam cooler and drain cooler have to be remove from the power plant. Therefore, the steam extraction from IP Turbine and drain water from HPH #2 will enter the HPH #3 without first being cooled so the heat load is increase. This is the reason why HPH #3 need to be redesign.
HPH #3 redesign process will be done by calculating with thermodynamics and heat transfer analysis. The variation will be focus on feedwater velocity and baffle spacing. Analysis process will be start by calculating the new heat load and log mean temperature difference of HPH #3. After that, overall heat transfer coefficient and heat transfer area will be calculated separately according to the zone (desuperheating and condensing zone). Then, the pressure drop on the tube and shell side can be calculated. The geometry and heat transfer calculation result in HPH #3 will be the input of ASPEN Fran simulation. This simulation purpose is to get the heat transfer area requierement and pressure drop on the tube and shell. The result from calculation and simulation method will be compared and analyzed.
The variation of feedwater velocity are 0,5m/s ; 1m/s ; 1,5m/s ; 2m/s. The variation of baffle spacing are (desuperheating/condensing) 0,3m/0,66m ; 0,35m/0,83m ; 0,4m/0,99m ; 0,45m/1,16m. Either from calculation or simulation, we can conclude that if the feedwater velocity increase, the overall heat transfer coefficient will be increase, therefore the heat transfer area will be decrease. But, the pressure drop on the tube side will be increase exponentially. If the baffle spacing is increase, the overall heat transfer coefficient will be decrease, therefore heat transfer area will be increase. Base on ghrapical analysis, the most optimum geometry of HPH #3 is when the feedwater velocity 1 m/s with baffle spacing of 0,3m/0,83m.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Uncontrolled Keywords: | High Pressure Heater, Feedwater, Overall heat transfer coefficient, Pressure Drop, Shell and Tube, Desuperheating, Condensing |
| Subjects: | T Technology > TJ Mechanical engineering and machinery |
| Divisions: | Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis |
| Depositing User: | Renaldo Maxillion Parinussa |
| Date Deposited: | 28 Jun 2021 01:25 |
| Last Modified: | 28 Jun 2021 01:25 |
| URI: | http://repository.its.ac.id/id/eprint/56418 |
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