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ABSTRACTIn order to respond the global issues regarding climate change and global warming in this new era of globalization, governments and environmentalists set the targets to provide an alternative, sustainable and renewable energy to decrease the pollution emerging from non‐sustainable sources such as a fossil fuels or petrodiesel. The increase in the use of biodiesel fuels is expected to be a better solution to help address the environmental problems impacting on society.Biodiesels are an alternative, environmentally friendly energy resources generated from the transesterification process of animal fats, vegetable oils and other organic resources. The transesterification process of biodiesels can be carried on by using an alkaline as the catalyst to separates the triacylglycerol into an alkyl ester and a glycerol compound. Through this separation, a friendly chemical component similar with a fossil fuel can be produced. Nevertheless, further characteristics of biodiesels need to be observed in order to maximize the performance of biodiesels on the diesel engine.This report will focus on surface tension and density experimental investigations of four biodiesel fuels and nine fractionated methyl ester based on temperature dependency. The results are evidence of the relationship between surface tension and density. Also, the temperature change data characterizes the impact of fatty acid chain length upon density and surface tension."

"Dalam rangka merespon berbagai isu global yang berkaitan dengan perubahan iklim dan pemanasan global di era globalisasi ini, pemerintah dan para pakar lingkungan menetapkan target untuk menggunakan energi alternatif, terbaharui, dan berkelanjutan untuk mengurangi polusi yang muncul dari sumber energi yang tidak ramah lingkungan seperti bahan bakar fosil atau petrodiesel. Biodiesel merupakan bahan bakar yang dapat diperbaharui serta lebih ramah lingkungan yang diharapkan dapat menjadi solusi yang baik untuk membantu mengatasi masalah lingkungan ini.Biodiesel merupakan sumber energi alternatif yang ramah lingkungan yang dihasilkan dari proses transesterifikasi lemak hewani, minyak nabati dan sumber organik lainnya. Proses transesterifikasi biodiesel dapat dilakukan dengan menggunakan alkali sebagai katalis untuk memisahkan triasilgliserol menjadi suatu ester alkil dan senyawa gliserol. Melalui pemisahan ini, komponen kimia yang mirip dengan bahan bakar fosil dapat diproduksi. Namun demikian, karakteristik biodiesel perlu diperhatikan lebih lanjut untuk memaksimalkan kinerja biodiesel pada mesin diesel.Skripsi ini berfokuskan kepada eksperimen dan penyelidikan terhadap tegangan permukaan dan massa jenis dari empat bahan bakar biodiesel alami dan sembilan metil ester fraksinasi berdasarkan ketergantungan temperatur. Hasil eksperimen ini memberikan bukti adanya hubungan antara tegangan permukaan dan massa jenis. Disamping itu, terlihat juga data perubahan suhu yang mencirikan dampak dari panjang – pendeknya rantai asam lemak pada kepadatan dan tegangan permukaan.

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In order to respond the global issues regarding climate change and global warming in this new era of globalization, governments and environmentalists set the targets to provide an alternative, sustainable and renewable energy to decrease the pollution emerging from non-sustainable sources such as a fossil fuels or petrodiesel. The increase in the use of biodiesel fuels is expected to be a better solution to help address the environmental problems impacting on society.

Biodiesels are an alternative, environmentally friendly energy resources generated from the transesterification process of animal fats, vegetable oils and other organic resources. The transesterification process of biodiesels can be carried on by using an alkaline as the catalyst to separates the triacylglycerol into an alkyl ester and a glycerol compound. Through this separation, a friendly chemical component similar with a fossil fuel can be produced. Nevertheless, further characteristics of biodiesels need to be observed in order to maximize the performance of biodiesels on the diesel engine.

This report will focus on surface tension and density experimental investigations of four biodiesel fuels and nine fractionated methyl ester based on temperature dependency. The results are evidence of the relationship between surface tension and density. Also, the temperature change data characterizes the impact of fatty acid chain length upon density and surface tension."

"Pada penelitian ini, pembentukan deposit dari biodiesel dengan variasi berbeda, yaitu B100, B100-NA, B100-BHT, B100-BHA, dan B100 PG dilakukan dengan metode hot room temperature test rig untuk mengetahui karakteristik dan mekanisme pembentukan deposit pada masing-masing variasi bahan bakar. Penggunan antioksidan dalam menghambat oksidasi pada biodiesel diharapkan dapat menjaga bilangan asam agar tetap rendah dan meningkatkan stabilitas oksidasi, dimana akan membantu dalam terjadinya pembentukan deposit yang berlebih didalam rang bakar. Penelitian ini bertujuan untuk menemukan temperatur yang optimal agar pertumbuhan deposit dapat dikendalikan.

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In this study, forming of deposits from biodiesel with different variation, that are B100, B100-NA, B100-BHT, B100-BHA, and B100 PG will be observed with hot room temperature test rig methode to find their characteristics and growth mechanisms of deposits from every biodiesel variation. The addition of antioxidant in biodiesel to be expected for slowing the biodiesel from oxidation, so the acid number of biodiesel doesn?t increase and improve oxidation stability, and help deposit for not over growing inside of cobustion chamber. This research programe was created to finding the optimum temperatur in order to decrease of deposits in combustion chamber."

"Pada penelitian kali ini, pembentukan deposit dibentuk dari dua jenis bahan bakar, yaitu B0 solar dan B100 biodiesel murni dilakukan dengan menggunakan metode plat panas untuk mengetahui karakteristik dan mekanisme pembentukan deposit, terbentuk melalui proses deposisi dan evaporasi yang dilakukan berulang kali pada tiap jenis bahan bakar. Pertumbuhan deposit dilihat dengan melakukan dua pengujian yaitu pengujian single droplet dan pengujian multi droplet. Melalui kedua pengujian tersebut, waktu evaporasi dan massa deposit dapat ditemukan. Penelitian ini bertujuan untuk menemukan temperatur untuk pengendalian pertumbuhan deposit.

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In this study, forming of deposits from biodiesel with different variation, that are diesel B0 and biodiesel B100 will be observed with hot surface plate method to find their characteristics and growth mechanisms, formed through repetitive process of deposition and evaporation that were done to every fuel variation. Growth was observed by using two methods of droplet testing, single droplet test and multi droplet test. This study program was created to finding the optimum temperature in order to control the forming of deposits in combustion chamber."

"Penelitian ini dilakukan dengan proses deposisi dan evaporasi bahan bakar Diesel yang dilakukan secara berulang pada sebuah pelat panas. Pelat dipanaskan dengan variasi temperatur di dalam ruang tertutup sehingga kondisinya mendekati kondisi riil pada engine. Pengujian ini menggunakan hot room temperature test rig. Dari pengujian ini, pengaruh temperatur terhadap pertumbuhan dan karakteristik deposit dapat diamati. Penelitian ini lebih mengarah ke struktur deposit. Struktur deposit yang berbeda di setiap temperatur dapat menunjukkan temperatur yang optimal untuk mengendalikan pertumbuhan deposit.

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Repetitive process of diesel fuel deposition and evaporation on hot plate are done in this study. The plate was heated at various temperature in closed systems for approaching the real engine condition. This process was done in hot room temperature test rig. Effect of temperature to deposits growth and characteristic could be observed through this repetitive process. Then, the aim of this study is more likely to deposits structure. Different deposits structure at every temperature could show the optimum temperature to control the deposits growth."

"Penelitian ini dilakukan dengan proses deposisi dan evaporasi bahan bakar diesel yang dilakukan secara berulang pada sebuah pelat panas. Pelat dipanaskan dengan variasi temperatur di dalam ruang tertutup sehingga kondisinya mendekati kondisi riil pada engine. Pengujian ini menggunakan hot room temperature test rig. Dari pengujian ini, pengaruh temperatur terhadap pertumbuhan dan karakteristik deposit dapat diamati. Penelitian ini lebih mengarah ke jumlah deposit. Jumlah deposit yang berbeda di setiap temperatur dapat menunjukkan temperatur yang optimal untuk mengendalikan pertumbuhan deposit.

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Repetitive process of diesel fuel deposition and evaporation on hot plate are done in this study. The plate was heated at various temperature in closed systems for approaching the real engine condition. This process was done in hot room temperature test rig. Effect of temperature to deposits growth and characteristic could be observed through this repetitive process. Then, the aim of this study is more likely to total deposits. Total deposits structure at every temperature could show the optimum temperature to control the deposits growth."

"Biofuel generasi kedua berbahan dasar limbah tandan kosong kelapa sawit menjadi isu yang menarik untuk mengatasi kelangkaan energi, namun proses pemurnian etanol ? air menjadi kendala utama sebab keduanya membentuk campuran azeotropik. Pemisahan etanol - air dengan teknologi membran merupakan teknologi separasi yang sedang dikembangkan karena hemat energi, efisien dan efektif untuk diaplikasikan dalam skala besar. Membran yang digunakan dalam penelitian ini adalah membran GVHP, PBTK, LSW, dan GSWP yang diproduksi Merck Millipore dengan variasi kondisi operasi yaitu volume permeate, suhu, tekanan, dan konsentrasi. Dari penelitian ini membran GVHP menunjukkan hasil terbaik dengan faktor separasi sebesar 3,03 dan permeabilitas 0,015 g cm-2 s-1 pada kondisi operasivolume permeate 10 mL, suhu 75°C, tekanan 60 psi, dan konsentrasi etanol 20% v/v. Penerapan membran GVHP untuk separasi bioetanol dari TKKS menunjukkan faktor separasi terhadap etanol sebesar 3,66, namun dengan faktor separasi terbesar ditunjukkan terhadap propanol 5,44 serta rejection asam asetat sebesar 96,66%. Berdasarkan analisis FE SEM membran GVHP menunjukkan degree of swelling terkecil sehingga teknologi membran GVHP ini efektif untuk memisahkan suspensi Saccharomyces cerevisiae hasil fermentasi tandan kosong kelapa sawit.

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Second Generation of Biofuel based on empty fruit buncheshas been interesting issue to be developed in order to overcome the extinction of non-renewable energy, however the purification of ethanol ? water becomes the main problem since both of them form azeotrope. Separation ethanol ? water using membrane technology is in demand separation technology due to the low energy requirement, effectiveness, and efficiency to be applicable in industrial scale. Membranes that are used in this research are GVHP, PBTK, LSW, and GSWP which are produced by Merck Millipore with variation of operation conditions such as permeate volume, temperature, pressure, and concentration.

The best result of ethanol - water separation is shown by GVHP membrane with separation factor 3.03 and permeability 0,015 g cm-2 s-1in the condition operation permeate volume 10 mL, temperature 75°C, pressure 60 psi, andethanolconcentration 20% v/v. Furthermore the usage of GVHP membrane to purify bioethanol from empty bunches results separation factor toward ethanol 3.66 while the biggest separation factor is owned by toward propanol 5.44 so as the rejection factor of acetic acid is 96,66%. Based on the FE SEM analysis to GVHP membrane, GVHP membrane did the least degree of swelling among others hence this technology is effective to separate Saccharomycess cerevisiae suspension from empty fruit bunches fermentation."

"ABSTRAKBiodiesel merupakan senyawa alkil ester dari asam lemak yang diolah dari sumber trigliserida alami terbarukan dan digunakan sebagai bahan bakar mesin diesel, biasanya dibuat melalui proses esterifikasi atau transesterifikasi. Dalam aplikasi maupun penyimpanannya, biodiesel berpotensi mengalami kerusakan akibat reaksi oksidasi karena faktor internal kandungan asam lemak tidak jenuh yang tinggi dan faktor eksternal udara, panas, atau cahaya yang mengakibatkan terjadinya perubahan karakteristik serta kualitas dari biodiesel. Untuk menjaga karakteristik dan kualitas dari biodiesel agar sesuai dengan standar yang telah ditetapkan, maka perlu ditambahkan antioksidan yang dapat menghambat terjadinya reaksi oksidasi pada biodiesel. Pada penelitian ini digunakan antioksidan Pyrogallol yang ditambahkan ke dalam biodiesel minyak sawit dengan berbagai konsentrasi dan berbagai suhu penyimpanan. Parameter biodiesel yang diamati selama masa penyimpanan adalah yang dapat mewakili terjadinya oksidasi yaitu, parameter yang dapat adalah perubahan viskositas kinematik, densitas, bilangan asam, dan bilangan iodin. Hasil penelitian menunjukkan bahwa penambahan antioksidan Pyrogallol dapat menghambat terjadinya reaksi oksidasi pada biodiesel. Penggunaan antioksidan dengan konsentrasi 0,1 pada suhu penyimpanan 30 C maupun 60 C diketahui dapat mempertahankan karakteristik dan kualitas biodiesel selama masa penyimpanan dari kerusakan akibat reaksi oksidasi.

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ABSTRACT

Biodiesel is an alkyl ester compound of fatty acids that is processed from a source of naturally renewable triglycerides and used as a fuel for diesel engines, usually made through esterification or transesterification processes. In the application and its storage, biodiesel has a potential to be damaged by oxidation reaction due to internal factors high unsaturated fatty acid content and external factors air, heat, or light resulting in changes of biodiesel rsquo s characteristics and quality. To maintain the characteristics and quality of the biodiesel to the established standards, it is necessary to add antioxidants that can inhibit the oxidation reaction in the biodiesel. In this research, Pyrogallol will be used as antioxidants and will be added to the palm oil biodiesel with various concentrations and various storage temperatures. The biodiesel parameters observed during the storage period are those that can represent oxidation, which are kinematic viscosity, density, acid number, and iodine number. The results of this research show that the addition of Pyrogallol antioxidants can inhibit the oxidation reaction in biodiesel. The use of antioxidants with a concentration of 0.1 at storage temperatures of 30 C and 60 C is known to maintain the characteristics and quality of biodiesel during storage from damage caused by oxidation reactions."

"In 2016, the mandatory use of biodiesel as a substitute fuel by up to 20%, as introduced by the Indonesian Ministry of Energy and Mineral Resources, forced vehicle manufacturers to invent suitable engines that would accept biodiesel. The use of biodiesel in such a large proportion is highly risky, particularly due to the formation of deposits in the combustion chamber engines. The previous method of fuel droplets are placed on a hot plate approach produces deposits are slightly different from those generated by a real engine, therefore to obtain realistic deposits it is necessary to modify this method so temperatures as hot as those in a real engine. In this study, the potential deposit formation of biodiesel fuel was examined by conducting the deposition process and the evaporation of fuel on a stainless-steel plate (SS), which was placed in a closed space. Deposit characterization was carried out on a hot plate using Scanning Electron Microscopy (SEM). The test results showed differences in the structures of the deposits produced by biodiesel and diesel fuel; fine structures were seen in the former, while those of the latter were rougher and more porous. Deposit results that are similar to what is seen in a real engine will be very helpful for knowing the patterns, structures, and mechanism of the formation of deposits in such an environment."

"Kurangnya stabilitas oksidasi biodiesel menyebabkan banyak kendala dalam pemanfaatannya. Untuk mengatasi hal ini, stabilitas oksidasi biodiesel perlu ditingkatkan melalui proses hidrogenasi parsial yang dapat dilakukan dalam reaktor multifasa. Reaktor Slurry Bubble Column, salah satu jenis reaktor multifasa, yang telah banyak digunakan dalam proses hydrotreating, berpotensi untuk menyelenggarakan proses ini dalam sistem kontinyu. Akan tetapi, belum ada penelitian yang mempelajari penggunaan reaktor Slurry Bubble Column untuk mengubah biodiesel menjadi H-FAME melalui proses hidrogenasi parsial. Oleh karena itu, tujuan penelitian adalah untuk mengembangkan model matematis reaktor Slurry Bubble Column 2 dimensi axis-symmetric untuk proses hidrogenasi parsial. Model yang akan dibangun didasarkan pada persamaan kontinuitas untuk transport massa dan transport energi dengan modifikasi koefisien dispersi, juga penurunan tekanan dan distribusi katalis di sepanjang sumbu reaktor dan disimulasikan pada COMSOL MultiPhysic 5.4. Dalam penelitian ini, digunakan model kasus dasar reaktor kolom berbentuk silinder vertikal dua dimensi. Reaktor ini beroperasi pada 500 kPa, suhu saluran masuk 150 ° C. Umpan terdiri dari metil linoleat murni yang mewakili biodiesel dan hidrogen murni. Kecepatan gas masuk adalah 0,02 m/s, dan kecepatan cairan masuk adalah 0,00025 m/s. Hasil simulasi menunjukkan bahwa konversi metil-linoleat adalah 76,98%, hasil H-FAME adalah 54,8% berat, dengan kemurnian 54,45% berat.

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Biodiesel`s lacks of oxidation stability presents many constraints in its utilization. To enhance this property, biodiesel needs to be upgraded through partial hydrogenation process which can be carried out in a multiphase reactor. Slurry bubble column, a type of multiphase reactor, which has been widely used in hydro-treating process, has potential to perform this process in a continuous system. However, no previous studies had shown the usage of slurry bubble column for upgrading biodiesel to H-FAME via partial hydrogenation process. Therefore, this study purpose was to develop a two-dimensional axis-symmetric reactor model for this process. The model was based on equation of continuity on mass transport and energy transport with dispersion coefficient, also pressure drop and catalyst distribution along the reactor axis and simulated on COMSOL MultiPhysic 5.4. In this study, a base case model, two-dimensional, axis-symmetry, vertical cylinder-shape slurry bubble column reactor was used. This reactor operated in 500 kPa, inlet temperature of 150 °C. The feed consisted of pure methyl-linoleate as biodiesel representation and pure hydrogen. The inlet gas velocity was 0.02 m/s, and the inlet liquid velocity was 0.00025 m/s. Simulation results show that the conversion of methyl-linoleate was 76,98%, H-FAME yield was 54.8% wt, with 54.45% wt purity. Keywords: Biodiesel, Partial Hydrogenation, H-FAME, Slurry Bubble Column Reactor, dispersion model, COMSOL, multiphase, Methyl Linoleate."