89 research outputs found
PEMANFAATAN BAHAN ORGANIK DARI SAMPAH PADAT PERKOTAAN DALAM INDUSTRI KOMPOS (Utilization of Organic Matter from Municipal Solid Wastes in Composit Industries)
No full textABSTRAK
Dewasa ini sampah padat yang dihasilkan oleh kota besar sudah sangat banyak dan berpotensial untuk menimbulkan dampak negatif terhadap lingkungan dan kesehatan masyarakat. Oleh karena sekitar tiga perempat dari sampah adalah biomassa maka terdapat kemungkinan untuk memproses sampah tersebut menjadi pupuk kompos. Dengan demikian berat dan volume sampah sisa yang terpaksa harus dibuang ke TPA dapat berkurang secara drastis. Proses fermentasi bahan organik ini dilakukan di pabrik kompos. Sebelum itu, harus terlebih dahulu dilakukan proses pemisahan secara mekanis dan seksama untuk memperoleh bahan organik murni dari sampah padat. Pemisahan dilakukan oleh beberapa pasang thrower (pelempar) dan fan (penghembus). Melalui contoh kasus sebuah pabrik kompos berkapasitas 50 ton per hari beberapa peralatan dan mesin penting yang lazim dijumpai pada pabrik kompos dijelaskan pada mekalah ini, demikian juga tipe dan ukurannya.
ABSTRACT
Recently a huge amount of municipal solid wastes produced in big cities causes serious environmental and health problems. Since nearly three fourth of the wastes is biomass, there is a potential to process the organic matter into agricultural compost. In this way, the weight and volume of wastes which are finally disposed in sanitary landfills can be drastically reduced. The fermentation process of biomass occurs in compost plants. However, a thorough mechanical separation of the organic matter from municipal solid wastes must be carried out first by using pairs of a thrower and a fan. Some important equipments and machineries in a typical compost plant are delineated based on a case of 50 tons per day capacity. Their appropriate types and dimensions are discussed as well
Pengaruh Suhu dan kecepatan pengaduk pada reaksi Ozonolysis dan Transesterifikasi Minyak Goreng Bekas
No full textA novel technology for biodiesel production from used cooking oil has been studied. It involves ozonolysis and transesterification in the biodiesel synthesis. The effect of temperature and agitation speed were studied in both ozonolysis and transesterification which has been working simultaneously. The ratio mol for used cooking oil and methanol was I : 5. The ozone concentration was 5.8 mol %, the acid catalyst was 4 % w/w. Result from this study showed that the highest methyl esters produced from this study was at the reaction temperature 30% and 400 rpm. Short chain methyl esters were produced from double bond cracking of unsaturated fatty acids whereas long chain methyl esters were produced from transesterification Ozonolysis was dominant at reaction temperature 20°C and 30°C whereas transesterification was dominant at reaction temperature 40°C. Total methyl esters was higher at 400 rpm compare to that at 300 rpm for both operation temperature of 30°C and 40°C
Akibat negatif lebih rendahnya efisiensi termal PLTN dibandingkan dengan PLTU.
No full textDisamping beberapa keunggulan nyata dalam penggunaan PLTN apabila dibandingkan dengan PL TU, maka PLTN masih mempunyai beberapa kelemahan. Salah satu kelemahan itu adalah lebih rendahnya efisiensi termal yang disebabkan oleh terbatasnya flux kalor yang boleh dilepaskan pada inti reaktor dengan mengingat suhu leleh dari bahan penyusun inti reaktor tersebut. Terbatasnya kalor yang dilepaskan ini menyebabkan suhu fluida pendingin reaktor juga terbatas. Dengan demikian fluida pendingin ini akan memberikan kalornya kepada fluida penggerak turbin (di dalam pesawat Pembangkit Uap) dengan suhu rata-rata yang lebih rendah. Lebih rendahnya efisiensi termal ini menyebabkan PLTN membuang kalor ke lingkungan sekitar yang lebih banyak dibandin
PEMROSESAN SECARA TERMAL SAMPAH PADAT DALAM RANGKA BAKAR
No full textAbstrak
Ada beberapa langkah untuk mengatasi problema sampah. Sebelum dibuang ke tempat penimbunan seharusnya sampah diproses terlebih dahulu. Salah satu tujuan pemrosesan ini ialah untuk mengurangi kadar karbon organik. Pemrosesan sebaiknya dilakukan secara termal di dalam rangka bakar.
Analisis model matematis telah dilakukan terhadap proses perubahan kadar karbon di sepanjang rangka bakar. Kecepatan berkurangnya kandungan karbon merupakan fungsi dari beberapa parameter, terutama: massa udara pembakaran dan suhu reaksi sampah. Massa udara pembakaran harus dioptimalkan untuk mencapai waktu proses yang sesingkat mungkin dan rangka bakar yang sependek mungkin
Pellet combustion characteristics and emission of cocoa pod shell and coal blends
No full textThis study was carried out to investigate co-firing of torrefied cocoa pod shells (CPS), coal, and their blends with torrefied CPS/coal of 45/55, 30/70, and 15/85. The pelleted samples were burned in a top-lit updraft (TLUD) stove to assess mass-loss rates, flame temperatures, and flue gas emissions. The results of the study showed that the mass-loss rates and flame temperatures of the blend were closer to the combustion characteristics of the coal along with the smaller percentage of CPS. CO and NOx emissions of the blends increased in proportion to the percentage of torrefied CPS in the blend. The supplement of CPS to coal had a significant effect on a reduction in SO2 emissions. Overall, this study showed that torrefied CPS can be used as a supplemental fuel in coal/biomass co-firing up to 15. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature
Effect of Air Supply Location and Equivalence Ratio on Thermal Performance of Downdraft Gasifier Fed by Wood Sawdust
No full textIn order to encounter the shortage of fossil fuel, many efforts have been performed by researchers worldwide to find out an alternative technologies of renewable energy conversion. Biomass gasification, one of many promising energy conversion technologies, becomes more attractive in recent years. The present work aims to investigate an effect of air tuyere-grate distance (i.e. 260, 330, 400 mm) and equivalence ratio (i.e. 0.15, 0.20, and 0.25) on thermal behavior of the small-scale downdraft gasifier fed by sawdust. The reactor has internal diameter of 300 mm and height of 725 mm (from grate to the top). The thermal behavior of the gasifier in terms of axial temperature of the reactor, volume fraction of carbon monoxide, hydrogen, methane and higher heating value of the producer gas, and also cold gas efficiency are observed and analyzed. The result indicates that tuyere position above the grate affects the performance of the gasifier. The maximum higher heating value of the producer gas and cold gas efficiency are found at optimum tuyere-grate distance of 330 mm and equivalence ratio of 2.0. The maximum higher heating value of the producer gas and cold gas efficiency are 2.84 MJ/Nm3 and 66.36%, correspondingly. 
Thermoelectric Generator as an Additional Energy Source for Motorcycle Engines
No full textAround 35% of gasoline combustion energy is wasted as heat in exhaust pipes of spark ignition engines. It represents not only energy losses but also thermal pollution and hazardous gas emission. Therefore utilizing this waste heat is strongly urged in order to minimize negative impacts of steadily increasing number of motorized vehicles. One of the possible methods is using a Thermoelectric Generator (TEG) to convert waste heat directly into electricity. The generated electricity can be used by the vehicles itself, and therefore contribute to improve engine efficiency, decrease fuel consumption and reduce gaseous emissions.
Thermoelectric Generator modules used in this research are TEG 127 - 40 A, made from Bismuth Telluride (Bi2Te.J which is most appropriate for lower temperatures, while the exhaust gas as the heat source is produced front one of the two investigated motorcycles, which have 110 cm3 and 150 cm3 displacement volumes, respectively. These modules are placed in three locations on the exhaust pipe. The first location is near the exhaust manifold, the second is between the exhaust manifold and the collector, while the third is close to the collector. Observations and measurements are carried out when the engine is idle (around 1500 rpm) and at 3000 rpm, both are on a test bed without load. Further data collections are conducted when the motorcycles run on the road with speeds of 20 km/hr, 25 km/hr 30 km/hr., respectively. Electrical power is obtained b)' serial connecting the three test points with a load of 1.4 Ohm from LED lamps.
The results showed that engine rotation speed and position of the TEG modules in the exhaust pipe affect the generated electrical energy. Likewise, power generation is influenced by cylinder capacity and running speed of the motorcycles. Maximum electrical power of the 110 cc engine at a speed of 30 km/li is 0.57 W, which is considerably smaller than that generated by the 150 cc engine at the same speed, where a power of 1.2 W is delivered. Actually the conversion efficiency is less satisfying, because the waste gas temperature is already relatively low (the maximum attainable is 230°C). Higher electrical power can be expected from larger engine capacities running at higher speed.
Keywords: Bismuth Telluride, Motorcycle exhaust pipe, Thermoelectric generators, Waste heat
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