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Abstrak :
Co-pirolisis termal antara bonggol jagung dan PP pada laju pemanasan rendah telah berhasil memisahkan bio-oil fasa oksigenat dan non-oksigenat secara spontan. Pada co-pirolisis, PP dapat mengambil oksigen dari bio-oil untuk mengkonversi sebagian bio-oil menjadi fasa non-oksigenat sehingga dapat berkontribusi dalam perengkahan PP. Namun, kemampuan PP untuk mengubah oksigen sangat lemah. Pada penelitian ini, zeolit digunakan sebagai katalis pada co-pirolisis bonggol jagung dan PP pada laju pemanasan rendah guna mengurangi energy aktivasi dari pirolisis PP, sehingga akan mengurangi suhu dekomposisi massa PP hingga kurang dari 400 oC. pada penelitian sebelumnya, belum pernah ada katalitik pirolisis menggunakan laju pemanasan rendah untuk meningkatkan yield fase non-oksigenat pada co-pirolisis biomass dan PP. Penelitian ini dilakukan di reaktor berpengaduk dengan laju pemanasan 5 oC/menit dan suhu pirolisis 500 oC. komposisi umpan yang digunakan adalah 0; 50 dan 100%PP. Katalis yang digunakan adalah katalis zeolit alam dan zeolit sintetik ZSM-5 dengan dua rasio Si/Al yang berbeda yaitu 38 dan 70. Penggunaan katalis menghasilkan produk senyawa alifatik seperti metil, metilen dan methin yang tingggi. Dengan penambahan tipe katalis zeolit ZSM-5 produksi dari alilik yang merupaan rantai yang berhubungan dengan alkena berkurang. Apabila dilhat dari kualitas bio-oil, sebagian besar fraksi bio-oil non-polar memiliki nilai HHV yang hampir sama atau sedikit lebih tinggi dari bahan bakar komersial yaitu diesel dan gasoline. Selain itu apabila dilihat dari nilai BI (Branching Index) bio-oil fraksi non-polar menghasilkan rantai karbon lurus dengan cabang yang lebih banyak apabila dibandingkan dengan bahan bakar komersial. Dari perbandingan HHV dan BI, nilai HHV dan BI bio-oil fraksi non-polar lebih mendekati nilai HHV dan BI dari gasoline komersial. ......Thermal co-pyrolysis of corn cobs and polypropylene (PP) at low heating rate has succeeded in separating bio-oil produced between oxygenated and non-oxygenated phases spontaneously. In co-pyrolysis, PP can sequester oxygen from bio-oil to convert part of bio-oil to non-oxygenated phase and can contribute partly non-oxygenated phase by PP carbon chain cracking. However, the capability of PP pyrolates to sequester oxygen is still low. In present work, zeolite catalyst was introduced in co-pyrolysis of corn cobs and PP at low heating rate, in order to reduce activation energy of PP pyrolysis and therefore reducing the lowest temperature of PP mass decomposition to less than 400oC. There has been no research previously conducted to employ catalytic co-pyrolysis at low heating rate to improve non-oxygenated phase yield in co-pyrolysis of biomass-plastic. The present co-pyrolysis work was carried out in a stirred tank reactor at heating rate of 5oC/min and maximum temperature of 500oC. The composition of feed was varied at 0, 50 and 100%PP in the mixture of corn cob particles and PP granules. There were two types of zeolite catalysts used in this experiment, natural zeolite and ZSM-5 with two different ratio, 38 and 70. Utilization of catalyst generated high amount of aliphatic moieties, i.e. methyl, methine and methylene. With ZSM-5 catalyst utilization, production of allyl decreased. Most of non-polar bio-oil fractions have similar or slightly higher higher heating values (HHVs) compared to those of commercial fuels. Branching index (BI) values of non-polar phase of bio-oil generated traight carbon chain with higher branches compared to those commercial fuels. From the comparison of HHV and BI value, non-polar phase of bio-oil generate HHV and BI value closer to commercial gasoline.

Abstrak :
Bio-oil produced by biomass pyrolysis contains high oxygenates, namely, carboxylic acids, alcohols, and ketones resulting in low calorific fuel, and therefore bio-oil requires upgrading to sequester these oxygenates. By conducting the co-pyrolysis of biomass and plastic feed blend, the donation of hydrogen by plastic free radicals to the oxygen of biomass free radicals may sufficiently reduce oxygenate compounds in the bio-oil and increase its yield. Therefore, the synergetic effects are functional. Currently, co-pyrolysis reactors have high aspect ratios (ratio of height to diameter) of 4 or more and small diameters (maximum 40 mm), in which the heat transfer from the furnace to the feed blend is immaterial even though the plastic material has low thermal conductivity. However, in large-scale reactors, such a design restricts the bio-oil’s capacity due to the heat transfer constraint. To resolve the latter and to improve bio-oil quality, in the present work, the co-pyrolysis of corn cobs and polypropylene (PP) is conducted in a stirred-tank reactor with a low aspect ratio (2). PP composition in the feed blend was varied from 0-100% weight with a 12.5% weight interval, heating rate of 5oC/min, and final temperature of 500oC. The results show that by increasing the PP composition in the feed blend from 37.5% to 87.5%, the bio-oil yield increased from 25.8% to 67.2% feed weight. An analysis of bio-oil quality shows that there was a favorably abrupt increase of non-oxygenate composition in the bio-oil from less than 5% to more than 70% as the PP composition in the feed blend was increased from 37.5% to 50% and more.

Abstrak :
Peningkatan penggunaan akan energi terbarukan yang ramah lingkungan menjadi alasan dalam perkembangan penelitian mengenai sistem penyimpan energi. Kepadatan daya dan energi menjadi salah satu faktor penentu pemilihan jenis sistem penyimpan energi. Kapasitor lithium ion (KLI) menjadi salah satu alternatif untuk menjawab kekurangan kepadatan daya pada baterai lithium ion (BLI) dan kepadatan energi pada superkapasitor. Nilai kapasitansi sebuah KLI dipengaruhi oleh karakteristik material katoda berupa luas spesifik permukaan, pori, dan kandungan unsur pada karbon aktif. Penelitian dan pengembangan karbon aktif berbasis biomassa sebagai material elektroda KLI telah menarik banyak perhatian dari para peneliti karena sumber daya biomassa yang melimpah, termasuk limbah tongkol jagung. Urgensi untuk menemukan alternatif karbon yang berbahan murah dan sederhana dapat diperoleh dengan mensintesis limbah tongkol jagung yang berlimpah dan cocok dengan sifat karbon. Penggunaan agen aktivator kimia selama proses aktivasi sangat penting untuk menghasilkan karbon aktif yang diinginkan, termasuk luas permukaan yang tinggi dan daya konduksi listrik yang baik. Di antara berbagai agen kimia, KOH dan ZnCl2 telah banyak digunakan mensintesis karbon aktif. Pada penelitian ini, karbon aktif berbahan tongkol jagung dengan variasi agen aktivator KOH dan ZnCl2 serta variasi rasio karbon dengan agen aktivator disintesis sebagai material katoda KLI dan dianalisis pengaruhnya terhadap kinerja KLI. Scanning electron microscopy (SEM), energy dispersive x-ray (EDX), Brunauer-Emmett-Teller (BET), serta Raman spectra digunakan untuk mengkarakterisasi karbon aktif. Hasil pengujian menunjukkan semua sampel memiliki pori berukuran mikro yang merata serta kandungan unsur karbon di atas 80%. Pori dengan ukuran terkecil terlihat pada sampel CACK12 dengan ukuran 0.2 µm. Luas permukaan karbon aktif berbahan tongkol jagung yang didapat baik dari agen aktivator KOH dan ZnCl2 dengan variasi karbon dan agen aktivator 1:3 (CACK13 dan CACZ13) tidak jauh berbeda yaitu: di kisaran nilai 800 m2/g. Kristalit yang terbentuk pada CACK dan CACZ berupa karbon amorf yang padat. Sampel karbon aktif yang dibuat selanjutnya disintesis menjadi katoda KLI dengan LTO sebagai material anodanya. Pengujian elektrokimia dilakukan melalui cyclic-voltammetry (CV) dan charge discharge (CD). Dari hasil pengujian didapat nilai kapasitansi spesifik tertinggi pada KLI-K3 dengan nilai 28,04 F/g dengan energi spesifik112,14 Wh/kg dan daya spesifik 1032.69 W/kg.

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The enhancement of renewable energy use which is environmentally friendly is the reason in the development of research on energy storage systems. Power and energy density is one of the determining factors in choosing the type of energy storage system. Lithium ion capacitors (LIC) are an alternative to answer the lack of power density in lithium ion batteries (LIB) and energy density in supercapacitors. The capacitance value of a LIC is influenced by the characteristics of the cathode material such as specific surface area, pore, and elemental content in activated carbon. The research and development of biomass-based activated carbon as a LIC electrode material has attracted much attention from researchers because of its abundant biomass resources, including corncob waste. The urgency to find carbon alternatives that are cheap and simple can be obtained by synthesizing corn cobs waste that is abundant and suitable with carbon properties. The use of chemical activator agents during the activation process is very important to produce the desired activated carbon, including high surface area and good electrical conductivity. Among various chemical agents, KOH and ZnCl2 have been widely used to synthesize activated carbon. In this study, activated carbon made from corncob with variations of activator agents KOH and ZnCl2 and variations in the ratio of carbon with activator agents were synthesized as LIC cathode material and analyzed for their effect on LIC performance. Scanning electron microscopy (SEM), energy dispersive x-ray (EDX), Brunauer-Emmett-Teller (BET), and Raman spectra are used to characterize activated carbon. The test results show all samples have a uniform micro-sized pore and carbon element content above 80%. The surface area of activated carbon made from corn cobs obtained from both KOH and ZnCl2 activator agents with carbon variations and 1: 3 activator agents (CACK13 and CACZ13) is not much different, namely: in the range of 800 m2 / g. The crystallites formed in CACK and CACZ are solid amorphous carbon. The activated carbon samples were then synthesized into KLI cathodes with LTO as the anode material. Electrochemical testing is done through cyclic-voltammetry (CV) and charge discharge (CD). From CV result KLI-K3 has the biggest specific capacitance 28,04 F/g with specific energy 112,14 Wh/kg and specific power 1032.69 W/kg.

Abstrak :
Previous research of thermal co-pyrolysis of biomass-plastics where plastics function as hydrogen donor to induce synergistic effect on non-oxygenated fraction of bio-oil has reached a condition that there was a difficulty of separating non-oxygenated compounds from oxygenated compounds either at low heating rate. It was suspected that the content of high molecular weight of compounds especially polyaromatic hydrocarbons (PAH) in bio-oil retarded this separation. At low heating rate, most of co-pyrolysis until recently have been conducted in fixed bed and auger reactors. The present work proposed a stirred tank reactor as the reactor alternative to avoid formation of PAH in bio-oil. A series of experiments of co-pyrolysis of corn cobs and polypropylene at low heating rate (5oC/min) with maximum temperature of 500oC has been conducted with the ultimate goal of producing non-oxygenated fraction of bio-oil similar to diesel fuel. The qualities of the fraction targeted were its viscosity, double bond content and branching number of carbon chains. The values of these properties in diesel fuel are 2.7 cStokes, 0%, 0.4, respectively. The experiments involved 3 different reactors, i.e. the first, a stirred tank reactor with its aspect ratio (the ratio of the height to the diameter) of 2.0, the second, a stirred tank reactor with aspect ratio of 1.35 and the third, a dispecement reactor. Nitrogen gas as a sweeping gas was predicted to generate local turbulence favouring convective heat transfer. The work has resulted in some important results, i.e. the first, there was phase separation between oxygenated and non-oxygenated fractions, the second, synergistic effects in copyrolysis have been achieved both in bio-oil and non-oxygenated fraction yields, the third, non-oxygenated fraction had viscosity of 2.03 + 6.47% cStokes, the fourth, nonoxygenated fraction contained only 6-7% double bonds, which eases the hydrogenation reaction in further processing for double bond saturation, the fifth, non-oxygenated fraction had average branching number of 0.57, slightly above that of diesel fuel, which is unfavourable to reach short ignition delay time in the combustion, the sixth, the aspect ratio of the reactor significantly affected the extent of biomass pyrolysis, but not polypropylene pyrolysis.

Abstrak :
Co-pyrolysis antara bonggol jagung dengan plastik polipropilena dilakukan di dalam reaktor tangka berpengaduk menggunakan gas CO2 sebagai gas pembawa karena ketersediaannya yang melimpah dan harganya yang murah. Percobaan dilakukan pada berbagai komposisi bonggol jagung dan plastik polipropilena untuk memperhitungkan pengaruh komposisi pada yield dan kualitas minyak nabati yang dihasilkan. Laju alir gas yang digunakan adalah 750 mL/menit dan laju pemanasan sebesar 5°C/menit hingga suhu mencapai 500°C. Hasil penelitian menunjukkan bahwa yield gas non-kondensibel dan char yang dihasilkan lebih banyak, sedangkan yield minyak nabati lebih sedikit dibandingkan saat gas N2 digunakan sebagai gas pembawa. Derajat percabangan molekul pada fraksi non-polar minyak nabati yang dihasilkan terbukti lebih besar dan kandungan aromatiknya lebih sedikit dibandingkan dengan bahan bakar komersial.