Judul: Study of biodiesel production by in situ transesterification of jatropha seed (jatropha curcas l.) on pilot scale
Abstrak: At present, energy demands have been steadily increasing along with growth of human population and industrialization. Common sources of energy are fossil-based fuels. This growing consumption of energy has rapidly depleted non-renewable sources of energy. The increasing cost and depletion of fossil fuels have motivated researchers to find an alternative source of renewable energy. Moreover, there are many disadvantages of fossil-based fuels, such as atmospheric pollution and environmental issues. Biodiesel (fatty acids methyl esters, FAME) is a promising alternative fuel to replace petroleum-based diesel that is obtained from renewable sources as vegetable oil, animal fat, and waste cooking oil. Vegetable oil are more suitable source for biodiesel production compared to animal fat and waste cooking since they are renewable in nature. Jatropha curcas L. (JCL) is an acceptable choice for biodiesel production because it is non-edible and can be easily grown. Conventional production of biodiesel from Jatropha seeds involve two main processing steps : oil extraction and transesterification to FAME. In this study, feasibility in situ transesterification of Jatropha seeds was investigated on pilot plant. It was found that methanol/hexane/seed ratio effected the yield significantly. With the following reaction conditions: reaction periode 6 hours, 600 rpm stiring speed, 400C reaction temperature, methanol/hexane/seed ratio 3:3:1, and 7 wt% of KOH, the biodiesel yield can reached 89.19%. This single step of in situ alkaline transesterification process therefore can be a potential route for biodiesel production that reduces processing steps and cost.
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Judul: Kajian Proses Produksi Biodiesel Melalui Transesterifikasi in situ Biji Jarak Pagar (Jatropha curcas L.) Pada Berbagai Kondisi Operasi
Abstrak: Biodiesel production is generally carried out through several stages of process. They are oil extraction, oil purification, and oil transesterification. Several steps that must be passed in the biodiesel production causing low efficiency and high energy consumption, resulting in high cost of biodiesel production. Therefore, it is necessary to develop a process that simplify the steps in biodiesel production, more efficient, low cost and low energy consumption, also be able to produce high quality of biodiesel through in situ transesterification. This study purposes to investigate on in situ transesterification of Jatropha curcas L. under various operating condition by studying the influence of temperature, stirring speed, and reaction time on the yield and quality of biodiesel. In situ transesterification of Jatropha seeds was carried out under the following process conditions : the moisture content of Jatropha seeds less than 1%, the particle size of 35 mesh, the methanol to hexane to seeds ratio of 6:1:1 (v/v/w), and the KOH concentration of 0.075 mol/L methanol. Operating conditions of in situ transesterification was varied at temperature of 40, 50, and 60ºC, reaction time of 3, 4, and 5 hours, and mechanical stirring of 700, 800, and 900 rpm. Analysis of variance showed that temperature, stirring speed, and reaction time did not significantly affected the yield and viscosity of biodiesel. Temperature, reaction time, and interactions between temperature, stirring speed, and reaction time significantly affected acid value of biodiesel. Temperature and interaction between temperature and stirring speed significantly affected saponification value and ester value of biodiesel. The experimental results showed that in situ transesterification conditions which recommended for commercial scale was at temperature of 40ºC, mechanical stirring of 700 rpm, and reaction time of 3 hours (A1B1C1). That condition was choosen because this condition used low energy than other operating condition. This was also supported by the results of statistical analysis showed that the yield and viscosity of biodiesel were not significantly different at all operating conditions, and biodiesel’s characteristics meets Indonesian Biodiesel Standard. The value of acid value, saponification value, ester value, and viscosity at A1B1C1 are 0.49 mg KOH/g, 201.36 mg KOH/g, 200.87 mg KOH/g, and 3.49 cSt.
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Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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