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"Laju pertumbuhan penduduk Indonesia memaksa konsumsi akan bahan bakar terus meningkat, karena saat ini bahan bakar telah menjadi salah satu kebutuhan utama masyarakat modern di Indonesia. Sebagian besar bahan bakar tersebut berasal dari minyak bumi yang dalam satu dekade ini produksinya mengalami penurunan di dalam negeri. Oleh sebab itu peluang pengembangan energi alternatif harus terus di kembangkan di Indonesia, salah satunya dengan membuat Pabrik dimetil eter dengan bahan baku utama gas sintesis. Gas sintesis ini diperoleh dari gas alam melalui proses autotermal reforming. Indonesia sendiri memiliki cadangan gas alam yang lebih besar ketimbang minyak bumi. Dimetil Eter dipilih karena merupakan bahan bakar alternatif yang ramah lingkungan. Proses pembuatan Dimetil Eter secara indirect melibatkan sintesis methanol, dehidrasi methanol, purifikasi dimetil eter hingga purifikasi methanol untuk di recylce. Dalam penelitian ini akan dijelaskan sistem pengendalian pada proses sintesis metanol hingga sintesis DME. Unit-unit yang terdapat pada proses sintesis metanol dan DME ialah unit heater, unit compressor, unit cooler, unit flash vaporation dan unit fix bed reactor. Sistem pengendalian yang dipilih untuk proses ini ialah jenis pengendali Proportional Integral karena dapat menangani hampir setiap situasi kontrol proses di dalam skala industri. Penelitian ini menggunakan pemodelan penyetelan pengendali Ziegler Nichols dan Lopez, lalu dibandingkan dengan nilai parameter kinerja pengendaliannya, yaitu Offset, Rise Time, Time of First Peak, Settling Time, Periode Osilasi, Decay Ratio, Overshoot, Deviasi maksimum, Integral of Absolute Error (IAE) dan Integral Square Error (ISE) dari kedua jenis penyetelan tersebut. Hasil penelitian ini dapat digunakan untuk penentuan variabel input dan output yang optimum pada proses sintesis Metanol dan DME yang dapat diterapkan pada pabrik DME. Berdasarkan hasil penelitian diperoleh bahwa unit heater 1 menggunakan metode Ziegler Nichlos (Kc 0,9978 ; Ti 0,1831), unit heater 2 menggunakan metode Ziegler Nichlos (Kc 0,2166 ; Ti 0,1249), unit compressor menggunakan metode Fine Tunning (Kc 5 ; Ti 0,1), unit cooler 1 menggunakan metode Ziegler Nichlos (Kc 0,1969 ; Ti 0,1199), unit cooler 2 menggunakan metode Ziegler Nichlos (Kc 0,5495 ; Ti 0,1815), dan unit sintesis DME menggunakan metode Ziegler Nichlos (Kc 0,16071 ; Ti 0,0699).

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Increases of Indonesia’s population makes consumption of fuel was high, because nowadays fuel become primary needs for modern people in Indonesia. Fuel in Indonesia is mostly from petroleum, which is has slowly production in one decade behind. Therefore, chance in alternative energy must be develop in Indonesia, one of them is making Industry of Dimethyl Ether (DME) from synthetic gas feed. Synthetic gas was get from natural gas in autothermal reforming process. Indonesia has more reserve natural gas than petroleum. The another benefit from DME is friendly for our environment as alternative fuel. Indirect process in production of DME consists of synthesis methanol, dehidration methanol, purification DME and purification methanol for recycle.

The research will explain about control system in Synthesis Methanol and DME. These process consist of heater, compressor, cooler, flash vaporation and fix bad reactor units. This research used tuning model Ziegler Nichols and Lopez, then compares the performance parameter of Offset, Rise Time, Time of First Peak, Settling Time, Osilation Period, Decay Ratio, Overshoot, Maximum Deviation, Integral Absolute Error (IAE) and Integral Square Error (ISE) by both tuning model. The result of this research can be use to define optimum input and output variable in Purification process of DME and Methanol that can applied in Industry of DME.

Based on this study’s result, achieved that heater 1 used Ziegler Nichlos method (Kc 0,9978 ; Ti 0,1831), heater 2 used Ziegler Nichlos method (Kc 0,2166 ; Ti 0,1249), compressor used Fine Tunning method (Kc 5 ; Ti 0,1), cooler 1 used Ziegler Nichlos method (Kc 0,1969 ; Ti 0,1199), cooler 2 used Ziegler Nichlos method (Kc 0,5495 ; Ti 0,1815), and synthesis DME used Ziegler Nichlos method (Kc 0,16071 ; Ti 0,0699)."

"Increasing energy demand, in line with the rate of population growth, is always followed by the pace of the waste dump. Where the largest percentage comes from organic waste, it is potentially utilized as raw material of biomass mixture for emission reduction efforts in fuel conversion from waste energy. The main objective of this paper is to study the characteristics of co-gasification, especially gasification temperature, lower heating value and gas emission, on the performance of the biomass gasification process in a downdraft fixed bed gasifier. In this study, organic waste used twigs, coconut fibers and rice husks in the pelletization as raw materials on the combustion technology Downdraft Gasifier. Methods were carried out by co-gasification techniques between WCF (wood-coconut fibers) pellet and rice husk on 100% pellet composition, 75:25, 50:50, 25:75 and 100% rice husk. Syngas testing is done with direct measurement on the burner with TCD type Shimadzu 8A gas chromatography. The highest reactor temperature in the pyrolysis zone was 400oC to 850oC and the temperature in the oxidation zone was 1000oC to 1200oC. The result of the synthetic gas testing obtained the highest lower heating value (LHV) in WCF 100% pellet composition at 4.07 MJ/Nm3 with 85% efficiency. The lower heating value of the lowest syngas in a 100% pellet composition was 2.99 MJ/Nm3, where the increase of WCF pellets will increase the LHV syngas value. This resulted in visually low tar content and low ash particles in all compositions of approximately 30 to 35% of the initial mass of each composition, with the lowest ash in 100% rice husk composition at 0.29 g."

"PLTBm merupakan salah satu alternatif untuk menyediakan kelistrikan di daerah 3T (Terdepan, Terluar, dan Tertinggal). Dalam hal ini feedstock yang digunakan adalah sekam padi. Sejalan dengan pengembangan syngas sekam padi sebagai bahan bakar alternatif, maka dalam penelitian ini difokuskan untuk mengevaluasi unjuk kerja dan mendapatkan pemanfaatan syngas yang ideal dan optimal untuk mesin spark ignition. Syngas berasal dari proses gasifikasi downdraft gasifier dengan bahan bakar sekam padi. Dilakukan pengujian dengan memberikan putaran konstan 1500 rpm pada generator listrik dengan mengevaluasi perbandingan antara penggunaan bahan bakar bensin beroktan 98 dan bahan bakar syngas. Pembebanan dimulai dari 1 kW sampai dengan 4 kW dengan interval 1 kW. Metode pemasukan syngas dengan T junction yang diletakan sebelum intake manifold untuk mencampur udara dan syngas. Pengukuran dilakukan terhadap laju massa alir udara, laju massa alir bensin, dan laju massa alir syngas. Temperatur kerja mesin, dan mengukur tegangan serta arus yang dihasilkan. Hasil penelitian menunjukan bahwa unjuk kerja mesin spark ignition mengalami perubahan efisiensi termal serta SFC yang lumayan besar antara bahan bakar bensin dengan bahan bakar syngas. Sedangkan,, untuk daya efektif, torsi dan juga BMEP tidak mengalami perubahan yang signifikan. Serta juga menghasilkan AFR untuk bahan bakar bensin cukup kaya bahan bakar sedangkan untuk bahan bakar syngas sudah mendekati 1:1 dengan udara luar.

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PLTBm is an alternative to provide electricity Front, Outermost, and Disadvantaged areas. In this case, the feedstock used was rice husk. In line with the development of rice husk syngas as an alternative fuel, this research is focused on evaluating the performance and obtaining the ideal and optimal use of syngas for spark ignition engines. Syngas comes from the downdraft gasifier gasification process with rice husk as fuel. Tested by providing a constant rotation of 1500 rpm on an electric generator by evaluating the comparison between the use of 98 octane gasoline and syngas fuel. Loading starts from 1 kW up to 4 kW with 1 kW intervals. Syngas intake method with a T junction placed before the intake manifold to mix air and syngas. Measurements were made on the mass flow rate of air, the mass flow rate of gasoline, and the mass flow rate of syngas, and then measure engine temperature, the voltage and the current generated. The results showed that the performance of the spark ignition engine change in thermal efficiency and a fairly large SFC between gasoline fuel and syngas fuel. However, the effective power, torque and also BMEP did not experience significant changes. Morever, produces AFR for gasoline fuel is quite rich in fuel while for syngas fuel it is close to 1:1 with outside air."