1,720,981 research outputs found
Penggunaan Ultrasonik untuk Transesterifikasi Minyak Goreng Bekas
Full text linkIn this work, the ultrasound-assisted transesterification of used frying oil (UFO) was studied. A two-step pretreatment of degumming and esterification was conducted to prepare UFO as raw material for transesterification. The esterification and transesterification was performed by using ethanol as solvent in the presence of ultrasonic irradiations operating at frequency of 40 kHz. The esterification was carried out with oil to ethanol ratio of 1:10, temperature of 60oC and reaction time of 4 hours in the presence of 1 wt .% H2SO4 as an acid catalyst. Meanwhile, the transesterification reaction was carried out with oil to ethanol molar ratio of 1:8, 1:10, 1:12, 1:15; KOH catalyst concentration of 0.5, 0.75, 1, 1.25 and 1.5 wt.%; and reaction temperature of 40, 50 and 60oC. The highest biodiesel yield of 65% obtained at ultrasound-assisted transesterification condition of oil to ethanol molar ratio of 1:12, reaction temperature of 50oC and KOH concentration of 1 wt.%. The results of analysis of some parameters of the product showed biodiesel has fulfilled the specifications according to the Indonesian National Standard (SNI) 04-7182-2006 number.Keywords: Biodiesel, Esterification, Used frying oil, Transesterification, Ultrasoni
Penggunaan Microsoft Excel dalam Memprediksi Aliran Fluida dalam Packed Bed
Full text linkFlow distribution is often a problem in the operation of the packed bed reactor. The problem is often referred as flow maldistribution and formation of localized hot spot region. This research is generally aimed to predict fluid flow distribution in the packed bed containing porous media by finite difference method using the software MS. Excel. Model verification result shows conformity between analytic method and result of calculation. Simple study of the finite difference method using the software MS. Excel can describe the fluid velocity profile in a packed bed containing porous media. This profile is similar with experiment of Kufner and Hofmann (1990) and Stephenson and Stewart (1986). The simulation was performed to determine the effect of process variables on the fluid flow velocity profile. Particle diameter influences fluid flow velocity. Bulk porosity also influences fluid flow velocity at axis up to certain distance from wall of reactor. Keywords: finite difference method, flow distribution, packed bed reacto
Use of Reactive Distillation for Biodiesel Production: A Literature Survey
Full text linkBiodiesel has been shown to be the best substitute for fossil-based fuels to its environmental advantages and renewable resource availability. There is a great demand for the commercialization of biodiesel production, which in turn calls for a technically and economically reactor technology. The production of biodiesel in existing batch and continuous-flow processes requires excess alcohol, typically 100%, over the stoichiometric molar requirement in order to drive the chemical reaction to completion. In this study, a novel reactor system using a reactive distillation (RD) technique was discussed for biodiesel production. RD is a chemical unit operation in which chemical reactions and separations occur simultaneously in one unit. It is an effective alternative to the classical combination of reactor and separation units especially when involving reversible or consecutive chemical reactions such as transesterication process in biodiesel production
Esterification of Free Fatty Acid in Crude Palm Oil Off Grade
Full text linkThe esterification of free fatty acids (FFA) found in crude palm oil (CPO) off grade with methanol is a promising technique to convert FFA into valuable fatty acid methyl ester (FAME, biodiesel) and obtain a FFA-free oil that can be further transesterified using alkali bases. In this work, the effects of the main variables involved in the esterification process i.e. alcohol to oil molar ratio, reaction temperature, agitation speed and the initial amount of FFA of oil, were studied in the presence of sulphuric acid as catalyst at concentration of 1%-w. The experimental results show that the esterification process could lead to a practical and cost effective FFA removal unit in front of typical oil transesterification for biodiesel production.Keywords: CPO off grade, esterification, free fatty aci
Prediction of Water Loss During Potato Vacuum Frying Process
Full text linkVacuum frying may be a good alternative for the production of dehydrated fruit and vegetable slices. In this study, a relationship between water losses with frying time during vacuum frying process of potato chips has been developed. A first order kinetic model was used, in which drying rate constant is a function of the main process variables, i.e. oil temperature, sample thickness and vacuum pressure. The experimental data of Garayo and Moreira (2000) have been used to validate the model. Generally there was a good agreement between the calculated results and the experimental data. Then, the effect of initial water content and vacuum pressure has been studied.Keywords: kinetic model, potato, vacuum frying, water los
Optimasi Proses Ekstraksi Oleoresin Jahe (Zingiber officinale Rosc) Menggunakan Ultrasonik
Full text linkThe study on extraction of oleoresin from ginger by using ultrasonic was carried out in order to obtain the optimum condition of extraction process. The effect of ratio of ginger to solvent (ethanol, X1), extraction temperature (X2), and extraction duration (X3) are studied on the yield of oleoresin. Response surface design method with Central Composite Design (CCD) was used to obtain a mathematical model which describes the relationship between the yield of ginger oleoresin and influencing variables. The experimental results indicate that the optimum condition of extraction which yield of oleoresin of 11.026% was found at ratio of ginger to ethanol (X1) of 1:4.68 gr.ml-1, extraction temperature (X2) of 420 OC, and extraction duration (X3) of 79 minutes.Keywords: extraction, response surface method, ginger oleoresin, ultrasoni
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Biodiesel Production from Waste Cooking Oil Using Hydrodinamic Cavitation
Full text linkThe aim of this research was to study biodiesel production from low cost feedstock of waste cooking oil (WCO) using hydrodynamic cavitation apparatus. A two-step processes esterification process and transesterification process using hydrodynamic cavitation for the production of biodiesel from WCO is presented. The first step is acid-catalyzed esterification process for reducing free fatty acid (FFA) content of WCO and followed by base-catalyzed transesterification process for converting WCO to biodiesel as the second step. The result of esterification process with methanol to oil molar ratio of 5 and temperature of 60 oC showed that the initial acid value of WCO of 3.9 mg KOH/g can be decreased to 1.81 mg KOH/g in 120 minutes. The highest yield of biodiesel in transesterification process of 89.4% obtained at reaction time of 150 minutes with methanol to oil molar ratio of 6. The biodiesel produced in the experiment was analyzed by gas chromatography-mass spectrometry (GC-MS), which showed that it mainly contained five fatty acid methyl esters. In addition, the properties of biodiesel showed that all of the fuel properties met the Indonesian National Standard (INS) No. 04-7182-2006 for biodiesel
Central composite design applied to purify lemongrass essential oil using vacuum distillation
No full textVacuum distillation process can be applied for purification of lemongrass essential oil byincreasing the concentration of citral in lemongrass essential oil. In this study, the relationship betweenexperimental parameters of purification of lemongrass oil was investigated. The effect of pressure,temperature and pH was examined to determine the best performance of the product yield. CentralComposite Design was applied to optimize the operating parameters of the process. It was found that theproduct yield of bottom product achieved an optimum level of 98.4% yield at the following reactionconditions, i.e. pressure of 55.9 mbar, temperature of 104.6oC and pH of 4.
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