Pendugaan Sisa Umur Pakai Kayu Komponen Cooling Tower di Pembangkit Listrik Tenaga Panas Bumi (PLTP) Unit II Kamojang
DOI:
https://doi.org/10.5614/jts.2012.19.2.2Keywords:
Creep, kayu, Cooling tower, Model, Sisa masa pakai.Abstract
Abstrak. Struktur cooling tower di PLTP (Pembangkit Listrik Tenaga Panas Bumi) Unit II Kamojang dibangun pada tahun 1988 dengan kayu sebagai komponen utamanya. Setelah 23 tahun umur pakainya, dirasa perlu dilakukan evaluasi sisa umur pakai sebagai salah satu bahan pertimbangan untuk memutuskan perobohan atau perpanjangan pemakaiannya. Evaluasi dilakukan melalui beberapa tahap yaitu: identifikasi jenis kayu dan keberadaan sisa bahan pengawet, pengukuran kedalaman kerusakan, pengujian sifat fisis mekanis, dan pemodelan matematis yang diturunkan dari uji creep dan pengurangan luas penampang kayu. Identifikasi memperlihatkan bahwa kayu yang dipergunakan untuk komponen utama cooling tower di PLTP Unit II Kamojang adalah redwood (Sequoia sempervirens) yang diawetkan dengan CCA (Chromated Copper Arsenat). Kerusakan telah terjadi sedalam 2,95 mm, namun secara umum masih memiliki tegangan ijin yang lebih tinggi daripada persyaratan NDS2005. Penelitian ini telah menghasilkan model terbaik yang dapat dipergunakan untuk menduga sisa masa pakai kayu komponen cooling tower di PLTP Unit II Kamojang dengan koefisien determinasi sebesar 86,84%.Abstract. Cooling tower in PLTP (Geothermal Power Plant) Unit II Kamojang was built in 1988, using solid wood as its main komponen. It is 23 years old nowadays, and should be evaluated to estimate its remaining lifetime. The evaluation conducted as scientific consideration for the company to decide wheter the cooling tower should be deconstruct or maintain to lenghten their lifetime. Some steps were conducted to estimate the remaining lifetime, namely: identification of wood species and the preservative remaining,measuring the depth of damages, measuring the physical and mechanical properties, and mathematical modelling which construct from creep testing and area reduction. This research show that the cooling tower was built with redwood (Sequoia sempervirens) which were treated with CCA (Chromated Copper Arsenat) preservative. The damage was happened until 2,95 mm depth, but the mechanical properties was commonly still better than NDS 2005 requirement. The research result mathematical equation which is suitable to predict the remaining lifetime of wood component in PLTP Unit II Kamojang with coefficient of determination 86,84%.
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