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"Penelitian pembakaran briket batubara bertujuan untuk mempersingkat waktu penyalaan. Penelitian dilakukan dengan memanfaatkan btiket promotor bentuk pola yang mengandung oksigenat etil asetat yang berfungsi sebagai penyedia oksigen secara internal dalam material briket karena ketidakcukupan oksigen saat briket promotor mengalami devolatisasi."

"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."

"Penelitian pembakaran briket batubara bertujuan untuk untuk mempersingkat waktu penyalaan. Penelitian dilakukan dengan memanfaatkan briket promotor bentuk bola yang mengandung oksigenat etil asetat yang berfungsi sebagai penyedia oksigen secara internal dalam material briket karena ketidak-cukupan oksigen saat briket promotor mengalami devolatilisasi (fungsi kinetika kimia) dan sebagai penguat terjadinya perpindahan panas konveksi dari bara api pada briket promotor ke briket pemasakan yang diletakkan disekitarnya karena adanya cekukan (dimples) pada permukaannya (fungsi perpindahan panas ). Briket promotor dalam kompor briket diletakkan di lapis kedua dengan loading 20% dari 3 lapis briket yang digunakan dengan lapis pertama, sisa lapis kedua dan lapis ketiga diisi briket pemasakan. Parameter kedalaman chimney dan kecepatan superfisial udara divariasikan untuk melihat efeknya terhadap waktu penyalaan. Kedalaman chimney divariasikan pada harga -harga 5, 15 dan 25cm dan pada masing - masing kedalaman chimney, kecepatan superfisial udara divariasikan pada harga-harga 0,6; 1,2 dan 1,8 m/s. Hasil penelitian menunjukkan bahwa pada kedalaman chimney 5 dan 15cm, semakin besar kecepatan superfisial udara, waktu penyalaan semakin singkat, tetapi penyingkatan waktu penyalaan tidak terlalu besar karena ada dua efek berlawanan yang bekerja bersamaan terhadap perpindahan panas konveksi yaitu efek turbulensi dan efek quenching. Waktu penyalaan berkisar antara 7,3 hingga 8,9 menit. Pada kedalaman chimney 25 cm, semakin besar kecepatan superfisial udara, waktu penyalaan semakin lama disebabkan oleh ketidakseragaman suplai udara pada kecepatan superfisial yang besar. Waktu penyalaan berkisar antara 8,5 hingga 10,3 menit. Pada kecepatan superfisial tertentu, kedalaman chimney 15cm memberikan waktu penyalaan yang lebih lama dibanding pada kedalaman chimney 5cm karena efek back pressure yang lebih besar pada kedalaman chimney 15cm.

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The research of coal briquette combustion is aimed of reducing the ignition time. It has been carried out by utilising ignition -promoting briquettes (promoters) of spherical - shape containing oxygenate ethyl acetate which functions of supplying oxygen internally in riquette material (kinetics function) and of enhancing convective heat transfer from smouldering part of the promoters to cooking briquette around the promoters in the presence of dimples on the promoter surface (heat - transfer function). The first function was introduced to avoid the insufficiency of oxygen environment around the promoters during coal devolatilisation of the promoters. Promoters in the stove was laid in the second layer of the briquette bed of the stove of 3 layers used and the cooking briquettes laid in the first layer (top layer), the rest of second layer and the third layer (bottom layer) of the bed. Loading of the promoters is about 20% of the second layer cross - sectional area. The parameters of the chimney depth and uperficial velocity were varied to observe their effects on the ignition time. The depth of chimney was varied at values of 5, 15 and 25cm and at each chimney depth value the superficial velocity was varied at values of 0.6; 1.2 and 1.8 m/s. The results of this research show that at the chimney depth of 5 and 15cm, the larger the superficial elocity, the shorter is the ignition time, though its effect is not significant. This may have been caused by the existence of two opposing effects, i.e. turbulence and quenching effects in which the former increases the convective heat transfer, while the later reduces the heat transfer. The ignition time range is 7.3 to 8.9 minutes. At the chimney depth of 25cm, the larger the superficial velocity, the longer is the ignition time. This may have been caused by more non - uniformity of the air supply at larger superficial velocity due to the location proximity between the stove grate and the blower at such deep chimney. The ignition time range is 8.5 to 10.3 minutes. At a given superficial velocity, the chimney depth of 15cm gave longer ignition time compared to that at the depth of 5cm as a result of back - pressure at deeper chimney during ignition."

"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."

"Torrefaction, which is used to improve the properties of sugarcane bagasse as fuel in pulverised fuel combustion and as carbon feed in gasification, is a low heating rate pyrolysis of biomass carried out at a temperature of 200–300oC, at an atmospheric pressure, and in an inert environment. In the present work, sugarcane bagasse was torrefied at heating rates of 3, 6, and 10oC/minute, respectively, to achieve a final temperature of 275oC and after the final temperature was reached, hold times of 0 and 15 minutes, respectively occurred at a constant temperature of 275oC for a heating rate of 6oC/minute. The physical characteristics of torrefied sugarcane bagasse samples to be determined were a particle size distribution accomplished by grinding, hydrophobicity by allowing the samples to absorb moisture from the ambient air, and pellet hardness of the sample pellets. The torrefaction results show that increasing heating rate and hold time reduced the cellulose content of the sugarcane bagasse to as low as between 5.35% to 10.61% by weight composition, respectively. As the lignin content increased, the sample pellets resulted in better hardness in comparison to that measured on raw sugarcane bagasse. As the hemicellulose content increased, the samples, after grinding and stronger hydrophobicity, produced a higher fraction of smaller particle sizes. The maximum weight fraction of particles in these samples with sizes smaller than 105 µm achieved was 83.43% weight in contrast to 0.62% weight in raw sugarcane bagasse. The maximum water absorption by the samples in 3 hours was 1.28% weight in contrast to 8.02% weight by raw sugarcane bagasse. The results indicate that torrefaction is able to improve sugarcane bagasse physical characteristics, which are favourable for biomass pelletization, storage and transportation."