Efek Penekanan Dan Pemanasan Pada Proses Pembriketan Biomassa Hasil Torefaksi Terhadap Kualitas Briket

Torefaction is one method of utilizing biomass waste into fuel through a thermal process that takesplace at atmospheric pressure with a temperature range of 200-350 ℃ to a solid quality fuelequivalent to sub-bituminous coal. Densification aims to increase biomass mass density. Thecombination of densification and torrefaction is an attractive process option to get high qualitybriquette and pellet fuel. Making briquettes with the hot printing method is able to eliminate theadhesive material so that the process of making briquettes is faster, direct briquettes can be usedwithout a drying process and are able to maintain the calorific value of raw materials. The purposeof this study is to examine the effect of suppression and heating on the briquetting process oftorefaction results on the quality of briquettes based on the physical properties of the drop test,water resistance, combustion temperature and length of combustion. The best quality briquettesfound were 8 tons of briquettes with a temperature of 150 ℃, where the briquette drop test did notlose much material. In water resistance testing, the water absorbed in 8 ton briquettes withtemperature of 150 ℃ is quite low, and when testing the combustion of briquettes is also quite good.Keywords : Torefaction, densification, briquettes, drop test, water resistant, combustion

Aktifasi Campuran Zeolit Alam Dan Flyash Batubara Menggunakan Microwave Sebagai Filter Udara Untuk Meningkatkan Akselerasi Mesin Sepeda Motor Bensin 4-Langkah

Combustion is a chemical process between fuel and oxygen utilizing heat. Ambient air contains avariety of gases such as nitrogen, oxygen, and other gases, causing incomplete combustion in thecombustion chamber of a 4-stroke petrol engine. The use of artificial air filters with zeolite-flyashcomposition activated by microwave can adsorb the air that enters the combustion chamber. So thatit can improve the quality of combustion. Zeolite is a mineral that is found in limestone mountainousareas, while coal flyash is material from coal combustion at PLTU. Both of these materials have theability to adsorb molecular sized particles such as nitrogen, CO and water vapor in the air, so theuse of both materials is able to produce air with rich oxygen. The performance of the 4-stroke petrolengine is influenced by a decrease in fuel consumption, able to increase acceleration, and reduceexhaust emissions containing CO and HC. To find out the effect of the use of activated zeolite-flyashfilters on engine performance, an acceleration test of 0-60 kph was performed. Filter beingactivated by Microwave with 80% power, 6 minutes activation time, and density (variation in thenumber of pellets in the filter) 50%, 75%, 100%, and use the Z0: F100, Z25: F75, Z50: F50, Z75:F25, Z100: F0. The best filter is the composition of Z100:F0 with a compactness of 50% able toincrease acceleration by 7.17%, followed by filter with composition of Z25:F75 with a compactnessof 50% able to increase acceleration by 4,04%.Keywords : Zeolites, Coal Flyash, Petrol Engine, Air Filters

Perancangan dan Perhitungan Sudu Turbin Angin Horisontal NACA 4412 Variasi Sudut Serang Menggunakan Simulasi BEM

The need for electricity in Indonesia becoming increasingly part of people's needs. Fossil fuels suchas oil and coal used as the main material for producing electrical energy the more limitedavailability, especially in its use of fossil fuels that pollute the environment. Wind energy is arenewable energy source that could potentially be developed. Wind energy is clean and does notpollute the environment in utilization into mechanical or electrical energy. The conversion of windenergy into electrical energy by converting this energy into mechanical rotation. In the wind energyutilization process made a tool to convert wind energy into electrical energy, that is windturbines.Wind turbine or windmill is a tool for converting wind energy. Wind turbines transformkinetic energy into mechanical energy in the form of a round shaft. Shaft speed is then used to rotatethe dynamo or a generator which produces electricity. The research was carried out on a horizontalaxis wind turbine NACA 4412, diameter 1 m, the number of blades 3 pieces and variations in windspeed 2-8 m / s. Results showed the greatest lift (CL) at 14o angle of attack with a value of 1.583.The driving force of the smallest (CD) at an angle of attack -4o to 2o with a value of 0.008. Value CL/ CD was found in the angle of attack of 6o with a value of 93.057. The maximum power generatedby 484.63 Watt. Wind speed, the number of blades, angle of attack and the election of the airfoileffect on the generated power.Keywords : wind energy, wind turbines, airfoil NACA 4412.

PENGARUH TEMPERATUR TEMPERING TERHADAP KEKERASAN DAN STRUKTUR MIKRO BAJA AISI 1045 YANG DIQUENCHING DALAM MEDIA PENDINGIN TERSIRKULASI

Steel AISI 1045 is steel classified as medium carbon steel because it has a carbon content of 0.45%.The characteristics of steel itself are sometimes not in accordance with the needs required,therefore the steel requires other treatments to change the properties and structure of steel AISI1045. The characteristics of steel can be changed by giving heat treatment, one of the processescarried out is the quenching tempering process. Quenching is a metal working process with rapidcooling to a predetermined variety of media with the aim of increasing the hardness of AISI 1045steel, while tempering is the process of reheating hardened steel with the aim of obtaining hightenacity and toughness.The quenching process uses a temperature of 800 °C with a waiting time of60 minutes and then cooled quickly with variations of diesel, water, and salt water with a 180°circulating process. While the tempering temperature variations used are 450 °C, 550 °C, and 650°C with a waiting time of 60 minutes. The results of the hardness test using the Rockwell method. inraw material testing get a value of 61.33 HRB hardness. The quenching results circulated in thesolar media are (80.6 HRB, 79.3 HRB, 81.3 HRB), the value of violence in the water media (89.3HRB, 89 HRB, 89.6 HRB), and salt water media (94,6 HRB, 96 HRB, 94.6 HRB). The hardnessvalue of temperature temperament 450 °C solar media (72.6 HRB 73 HRB, 72.6 HRB), water media(83.6 HRB, 82.6 HRB, 83 HRB), salt water (86.3 HRB, 86.6 HRB, 87.3 HRB). Temper temperaturehardness value of 550 ° C solar media namely (70.3 HRB, 70.3 HRB, 70.6 HRB) water media (81.3HRB, 81.3 HRB, 80.6 HRB) salt water media (84,3 HRB, 83.6 HRB, 84.6 HRB). The hardness valueof temperature variation of 650 °C, solar media are (68.3 HRB, 68.6 HRB, 68.6 HRB) water media(79 HRB, 79.3 HRB, 79.3 HRB) and salt water media (81,3 HRB, 81.6 HRB, 82 HRB). Themicrostructure obtained in quenching is the martensite structure and the tempering structure istemper martensite.Keywords: AISI 1045, quenching, tempering, martensite, ferrite, pearlite, HRB

PENGARUH PEMANFAATAN FILTER UDARA BERBAHAN ZEOLIT TERAKTIVASI FISIK MENGGUNAKAN Microwave TERHADAP AKSELERASI SEPEDA MOTOR BENSIN 4-LANGKAH

Atmospheric contains a variety of gases such as 78% nitrogen, 21% oxygen and 1% other gases.This causes incomplete combustion. Because the main composition of the combustion process is fueland oxygen. The use of zeolite physically activated by microwave which can increase the quality ofcombustion air. Zeolite is a type of rock that is capable of absorbing (capturing) molecularparticles or angstroms such as water vapor and nitrogen in the air. So that it will produce a richoxygen in the air when entering the combustion chamber. The performance of a 4-stroke motorcycleengine is good if there is a decrease in fuel consumption, it can increase the acceleration, andreduce exhaust emissions containing CO and UHC. To find out the effect of the zeolite filters onengine performance, an acceleration test of 0–80 km / h is performed. Zeolite is activated using amicrowave with 80% power, activation time is 3, 6, and 9 minutes, with gap of 75%. Then zeolitewas activated with 80%, 60%, and 40% power of microwave using 50%, 75%, and 100% gap(varying the gap arrangement of pellets). When the activation time of the filter is 3 minutes, it takes12.54 seconds to conduct, 6.53% faster, the a 6 minutes activation takes 12.58 seconds and 6.19%faster. The greater the activation power, the better acceleration. In the 80% acceleration test, 50%gap can increase the acceleration by a percentage of 6.16%. Meanwhile, the gap of 75% and 100%it can increase the acceleration by 5.64% and 3.86%.Keywords: Zeolite, physical activation, using microwave, increase acceleration

Pemanfaatan Campuran Zeolit dan Arang Sekam Teraktifasi Fisik Sebagai Filter Udara Untuk Meningkatkan Akselerasi Mesin Sepeda Motor Bensin 4- Langkah

Proses pembakaran adalah proses transfer energi panas yang terjadi pada ruang bakar yangdisebabkan karena terjadinya proses kimiawi antara bahan bakar dan oksigen yang menggunakanpanas awal. Komponen utama dalam pembakaran adalah udara, panas dan bahan bakar. Oleh karenaitu, dalam penelitian ini kemampuan campuran zeolit dan arang sekam sebagai adsorben (mampuuntuk menyerap) yang dijadikan sebagai filter udara dimanfaatkan untuk menyaring udarapembakaran guna meningkatkan prestasi mesin motor bensin 4-langkah yang dipengaruhi olehpeningkatan akselerasi mesin. Untuk mengetahui pengaruh penggunaan filter zeolit dan arangsekam teraktivasi fisik terhadap prestasi mesin maka, dilakukan pengujian akselerasi dengankecepatan 0-80 km/jam dan kecepatan 40-80 km/jam. Komposisi campuran zeolit-arang sekamdisimbolkan dengan Z0-S100, Z25-S75, Z50-S50, Z75-S25 dan Z100-S0 yang telah dilakukanproses aktivasi fisik dengan variasi temperatur 175 0C, 200 0C dan 225 0C selama 60 menit. Filterterbaik yang mampu meningkatkan akselerasi mesin pada kecepatan 0-80 km/jam dan 40-80km/jam adalah sama pada komposisi (Z75-S25) temperatur aktivasi fisik 225 0C. Pada kecepatan 0-80 km/jam mampu meningkatkan akselerasi sebesar 24,67% dan pada kecepatan 40-80 km/jammampu meningkatkan akselerasi sebesar 27,65%.Kata kunci : Filter zeolit-arang sekam, aktivasi fisik, prestasi motor bensin