Analisis Penggantian Pre-Cooler Untuk Turbin Gas (Studi Kasus Pada PLTG 3 Alstom di PT PT. PLN (Persero) Sektor Keramasan , Palembang, Sumatera Selatan)

Pardede, Anggi Raymond Octorius (2016) Analisis Penggantian Pre-Cooler Untuk Turbin Gas (Studi Kasus Pada PLTG 3 Alstom di PT PT. PLN (Persero) Sektor Keramasan , Palembang, Sumatera Selatan). Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pre-cooler merupakan salah satu komponen alat penukar kalor yang penting dalam sistem pembangkit listrik tenaga gas. Seperti prinsip alat penukar kalor pada umumnya, pre-cooler berfungsi untuk menurunkan temperatur udara dari Compressor Discharge Pressure (CDP). Udara tersebut akan dimanfaatkan sebagai pengabut bahan bakar dan pendingin fuel nozzle. Atomisasi bahan bakar berfungsi untuk menghasilkan proses pembakaran yang bagus, sedangkan pendinginan fuel nozzle diperlukan agar nozzle tidak mengalami kerusakan sehingga nozzle memiliki waktu operasi yang lama. Pada pola operasi yang kontinu, pre-cooler memiliki modus kegagalan yaitu mengalami kebocoran yang diakibatkan pengikisan oleh fluida kerja dan getaran yang berlebih. Ketidakefisien suatu alat dapat menyebabkan kerugian energi yang besar, seperti biaya produksi meningkat dan menurunnya kualitas produksi. Oleh karena itu, perlu dilakukan redesign pre-cooler agar tidak terjadi penurunan performa. Pada penelitian tugas akhir ini, penggantian pre-cooler dilakukan dengan merancang ulang pre-cooler dengan 3 jenis heat exchanger, yaitu shell-and-tube, plate-fin, dan circular finned tube. Redesign dilakukan dengan analisis perpindahan panas. Variabel yang divariasikan adalah geometri masing-masing tipe pre-cooler. Pitch ratio dan baffle spacing digunakan sebagai variasi geometri untuk shell-and-tube, sedangkan circular finned tube menggunakan variasi surface designation yang diambil dari buku M. Kays dan W. London. Batasan atau constraint yang ditentukan untuk pre-cooler tipe compact adalah volume ruang penempatan pre-cooler. Metode yang digunakan dalam perancangan adalah metode NTU dan LMTD yang meliputi perhitungan perpindahan panas untuk fluida sisi eksternal dan internal, perhitungan area perpindahan panas, heat transfer actual, overall heat transfer coefficient, dan efektivitas. Berdasarkan hasil penelitian, didapatkan bahwa pada existing pre-cooler, nilai efektivitas sebesar 0.592 dan number of transfer unit sebesar 1.01. Desain optimum hasil rancangan precooler dengan tipe shell and tube terdapat pada variasi pitch ratio 1.25 dan baffle spacing 0.2 IDshell . Sedangkan desain optimum tipe circular finned tube terdapat pada konfigurasi CF-8.7- 5/8J(a). Berdasarkan komparasi kedua tipe, circular finned tube memiliki kemampuan perpindahan panas yang lebih baik dibandingkan dengan shell and tube. Hal tersebut ditunjukkan melalui efektivitas circular finned tube sebesar 0.7, sedangkan shell and tube memiliki efektivitas 0.63. ================================================================================================================== Pre-cooler is a heat exchanger device in the gas turbine power plant that used to lowering the temperature of discharge air from the compressor. Cooled air will be used to atomise the fuel in a combustor as well as a coolant for fuel nozzle. The atomization process aims to produce a better fuel firing quality, whereas the cooling process of fuel nozzle intended to maintain the nozzle from breakdown as a result of protracted operational time. Insufficiency of an installation could cause a system failure It is, therefore, one of the means to prevent the degradation of performance of the device, pre-cooler needed to be replaced in such a way and analysed thoroughly. In this research, replacement of pre-cooler is done by redesigning into three kinds of heat exchangers, which are shell and tube and circular finned tube. In designing the pre-cooler for shell and tube type, baffle spacing and pitch diameter are the discrete variables. Whilst, for the circular finned tube type, is varied by its surface designations. The analysis that used in this research uses heat transfer analysis through LMTD and NTU method. Each type of heat exchangers varied by its surface designations. These methods are used to obtain heat transfer for both of the fluids, heat transfer areas, overall heat transfer coefficient, and effectiveness. Furthermore, in this research, pressure drops is also being analyzed for both of the types. From the research regarding existing pre-cooler, through NTU method analysis, the effectiveness of its pre-cooler is of 0.592 and Number of Transfer Unit is of 1.01. The optimum design from the new design pre-cooler with shell and tube type is obtained at variation of pitch ratio of 1.25 and baffle spacing of 0.2 IDshell. Meanwhile, the optimum design for circular finned tube is at configuration of CF-8.7-5/8J(a). Based on the results of the comparison of both pre-cooler, circular finned tube has a better quality in heat transfer. It can be shown by its effectiveness value of 0.7, whilst the shell and tube has 0.63 of its effectiveness.

Item Type: Thesis (Undergraduate)
Additional Information: RSM 621.165 Par a
Uncontrolled Keywords: Pre-cooler; re-design; LMTD; NTU; shell an tube heat exchanger; circular finned tube heat exchanger effectiveness
Subjects: T Technology > TJ Mechanical engineering and machinery > TJ778 Gas turbines
Divisions: Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User: ansi aflacha
Date Deposited: 30 Jun 2020 03:16
Last Modified: 30 Jun 2020 03:16
URI: http://repository.its.ac.id/id/eprint/76256

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