Doctor of Engineering in Metallurgy and Materials** J o h n y W a h y u a d i S o e d a r s o n o

Indonesia to be the world's second-largest contributor of plastic waste in the oceans. Every resident in Indonesia can produce 0,52 kg/person/day of waste. Efforts to overcome the problem of waste by processing it into Pellets, which contain calories from 2,800 to 3,300 kcal/kg using the peuyeumisasi method, so that they can use for co-firing in PLTU. Trial for direct co-firing coal and RDF Pellet from Klungkung Bali, will be carry out on Circulating Fluidized Bed Combustion (CFBC) boiler. The goal of study to analyze the feasibility for co-firing with SWOT analysis. The SWOT analysis questionnaire was compiled based on internal and external factors, which was carried out through the study of literature and document. After the questionnaire was compiled, the questionnaire was given to respondents who collected 10 people, selected based on factors of relevance and understanding of the issues discussed. The results of the questionnaire show the main indicators, which are divided into 2 parts, internal factors consisting of strengths, weaknesses and external factors consisting of opportunities and threats. Then implemented in the SWOT matrix, to get the best strategy and whether the decision is feasible or not. The results is feasible to be implemented in the PLTU MSW, withinternal factor value of 3,03 or rounded to 3 (strong) and an external factor value of 2,6 or rounded to 3 (strong). Several strategies are designed to use the strength to take advantage of opportunities, reduce weaknesses and threats. ABSTRAKIndonesia berada pada peringkat ke dua di dunia penyumbang sampah plastik ke laut. Setiap penduduk di Indonesia dapat menghasilkan sampah sebanyak 0,52 kg/jiwa/hari. Upaya mengatasi permasalahan sampah dengan mengolahnya menjadi Pellet yang mengandung kalori 2800-3300 kcal/kg menggunakan metode peuyeumisasi, sehingga bisa dimanfaatkan PLTU untuk dicampur dengan batubara (co-firing). Uji coba direct co-firing batubara dan Pellet sampah dari Klungkung Bali akan dilakukan pada boiler tipe Circulating Fluidized Bed Combustion (CFBC). Penelitian ini bertujuan menganalisa kelayakan cofiring Pellet sampah dan batubara dengan pendekatan analisis SWOT. Kuesioner analisis SWOT disusun berdasarkan identifikasi faktor internal, dan eksternal yang dalam penelitian ini dilakukan melalui studi pustaka terhadap dokumen dan literatur terkait. Setelah kuesioner disusun, kuesioner diberikan kepada responden yang berjumlah 10 orang, dipilih berdasarkan faktor keterkaitan serta pemahaman terhadap masalah yang diteliti. Hasil kuesioner menunjukkan penilaian terhadap indikator-indikator utama, yang terbagi ke dalam 2 bagian, yaitu : faktor internal berupa strengths (kekuatan), weakness (kelemahan) serta faktor eksternal berupa opportunities (peluang) dan threats (ancaman). Kemudian diimplementasikan dalam matriks SWOT, untuk mendapatkan strategi terbaik serta keputusan layak atau tidaknya. Hasilnya adalah layak diimpelmentasikan pada PLTU MSW, dengan nilai fakot internal 3,03 atau atau dibulatkan menjadi 3 (kuat) dan nilai faktor e...

Liquid Lead-Bismuth Eutectic (LBE) has been proposed as one of the coolant for the Generation IV nuclear reactor. However, the oxygen should be controlled adequately to suppress the corrosion rate of the LBE. A device called oxygen sensor made of zirconia as solid electrolyte has been used to monitor the oxygen concentration online in order to control the oxygen concentration. The principle of this sensor is based on electrochemistry method where the difference oxygen activitiy between reference electrode (RE) and working electrode (in liquid LBE) can make potential difference. The potential difference is measured by electrometer and can be converted into oxygen concentration based on Nernst equation. Iron (Fe)/Magnetite (Fe3O4) was used as material for RE in this study. Measurement of oxygen concentration was conducted at 450 - 600°C for the static condition of LBE and around 390°C for the dynamic condition of flowing LBE. The oxygen concentration for both two experiment conditions were set in oxygen saturated condition of Pb-Bi. The oxygen sensor based on zirconia solid electrolyte with Fe/Fe3O4 as RE can measured the oxygen concentration in liquid LBE. The results showed that the measurement was agreed with the Nernst equation theoretical calculation.

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Solid oxide structure of the cobalt-free composite has been exploited as a new cathode material for IT-SOFCs. The composite model system was synthesized using the metallic oxide material, which was formed by a solid-state reaction technique. The generation of the Sm0.5Sr0.25Ba0.25FeO3-δ (SSBF) model system was carried out during the sintering process. The weight loss and oxygen content were investigated by thermal gravimetric analysis (TG). Meanwhile, X-ray diffraction characterized the structure of the composite and thermal conductivity tested the conductivity properties. The results showed that the structure of the SSBF composite demonstrated the perovskite single phase leading to the structural design. The decomposition and evaporation of the constituent elements of the composite corresponded to weight losses during the constructing process. The oxygen content of the model system was 2.98 after the calcination process. The electrical conductivity value reached 2 S cm-1 at 400 °C and increases to a maximum of 7.5 S cm-1 at 710 °C. The metallic element played to generating the conductive behavior at the low temperature, while the ionic structure acted as elevated temperature. So, mixed ionic and electric conductors (MIEC) were employed comprehensively for creating the conductive properties. Based on the structure and conductivity results, the SSBF composite has a good chance as an alternative cathode material with a perovskite single phase for future TI-SOFCs applications