Jurnal Reaktor

95-100

Authors: Yulius Deddy Hermawan, Gogot Haryono

The open loop experiment of composition dynamic in a 10 L mixing tank has been successfully done in laboratory. A 10 L tank was designed for mixing of water (as a stream-1) and salt solution (as a stream-2 with salt concentration, c2 constant). An electric stirrer was employed to obtain uniform composition in tank. In order to keep the liquid volume constant, the system was designed overflow. In this work, 2 composition control configurations have been proposed; they are Alternative-1 and Alternative-2. For Alternative-1, the volumetric-rate of stream-1 was chosen as a manipulated variable, while the volumetric-rate of stream-2 was chosen as a manipulated variable for Alternative- 2. The composition control parameters for both alternatives have been tuned experimentally. The volumetric-rate of manipulated variable was changed based on step function. The outlet stream’s composition response (c3) to a change in the input volumetric-rate has been investigated. This experiment gave Proportional Integral Derivative (PID) control parameters. The gain controllers Kc [cm6/(gr.sec)] for Alternative-1 and Alternative-2 are -34200 and 40459 respectively. Integral time constant ( tI) and Derivative time constant (tD) for both alternatives are the same, i.e. tI = 16 second, and tD = 4 second. Furthermore, closed loop dynamic simulation using computer programming was also done to evaluate the resulted tuning parameters. The developed mathematical model of composition control system in a mixing tank was solved numerically. Such mathematical model was rigorously examined in Scilab software environment. The results showed that closed loop responses in PID control were faster than those in P and PI controls.

109-117

Authors: Yuswan Muharam, Chandra Hadiwijaya, Jacquin Suryadi

One of the characteristics of gasoline fuel is anti-knock property represented by its octane number. The determination of octane numbers in Indonesia is by using cooperative fuel research engines. The usage of cooperative fuel research engines in Indonesia has constraints, i.e. the limited number of the units and the old age. This study aims to obtain the octane numbers of commercial fuels by using kinetic models. The kinetics models of the oxidation and combustion of primary reference fuel and multi component hydrocarbons are used to calculate the ignition delay times of primary reference fuel and commercial fuels, respectively. The ignition delay times of primary reference fuel and commercial fuels are calculated at the same initial pressure and temperature, as well as the same equivalence ratio. The octane number of a commercial fuel is known if its ignition delay time agrees with that of PFR possessing a certain volume percentage of isooctane. The model generates the octane numbers of commercial fuels BB-A being 92.5, BB-B being 94.5, BB-C being 89, BB-D being 90.5 and BB-E being 91.5 with the good agreement with those claimed by the fuel producers.

123-128

Authors: Nyoman Puspa Asri, Siti Machmudah, Wahyudiono Wahyudiono, Suprapto Suprapto, Kusno Budikarjono, Achmad Roesyadi, Mitsuru Sasaki, Motonobu Goto

A benign process, non catalytic transesterification in sub and supercritical methanol method was used to prepare biodiesel from vegetables oil. The experiment was carried out in batch type reactor (8.8 ml capacity, stainless steel, AKICO, JAPAN) by changing the reaction condition such as reaction temperature (from 210°C in subcritical condition to 290°C in supercritical state with of 20°C interval), molar ratio oil to methanol (1:12-1:42) and time of reaction (10-90 min). The fatty acid methyl esters (FAMEs) content was analyzed by gas chromatography-flame ionization detector (GCFID). Such analysis can be used to determine the biodiesel yield of the transesterification. The results showed that the yield of biodiesel increases gradually with the increasing of reaction time at subcritical state (210-230oC). However, it was drastically increased at the supercritical state (270-290oC). Similarly, the yield of biodiesel sharply increased with increasing the ratio molar of soy oilmethanol up to 1:24. The maximum yield 86 and 88% were achieved at 290oC, 90 min of reaction time and molar ratio of oil to methanol 1:24, for soybean oil and palm oil, respectively.

135-142

Authors: Elida Purba, Kenjiro Siburian

The determination of salinity and nutrition (NaH2PO4) profile in Nannochloropsis oculata cultivation to gain maximum lipid was investigated. The purpose of this research was to determine the optimum salinity and nutrition (NaH2PO4) to gain maximum lipid in Nannochloropsis oculata. Phosphor can be obtained by adding NaH2PO4 and a salinity enhancement can be applied by adding NaCl to the culture. This research was run by matching each variable of salinity (33, 34, 35, and 36 ppt) to each variable of NaH2PO4 (5, 10 and 15 ppm) randomly. The results show that the percentage of maximum lipid in Nannochloropsis oculata was obtained at 35 ppt and 5 ppm NaH2PO4 (37.68 %). Nevertheless the maximum lipid percentage is low and it can be caused by some factors, such as the drying temperature for preparing the dry microalgae to extract, the cell disruption method and the extraction solvent used. By seeing the results, salinity can affect the total lipid in Nannochloropsis oculata. The greater the salinity in culture the greater the lipid content in Nannochloropsis oculata. Otherwise a different response was obtained by adding NaH2PO4. If NaH2PO4 concentration is greater, the lipid contained Nannochloropsis oculata will be lower

151-157

Authors: Maria Ulfah, Subagjo Subagjo

Effect of surface characteristics of three species of synthesized γ-alumina (alumina-1, alumina-2 and alumina-3) on characteristics NiMo catalysts has been studied. Those aluminas are derived from boehmite Catapal B by varying rasio mol nitric acid to boehmite. A sol-gel method is used to synthesize γ-Al2O3 support. The Nitrogen adsorption, X-ray diffraction (XRD), Temperature Programmed Reduction (TPR) of H2, Temperature Programmed Desorption (TPD) of NH3, and mechanical strength are used to characterize the supports and catalysts. The results showed that the surface area alumina affects the formation of crystalline MoO3 in the NiMo catalyst, while γ-Al2O3-3 support which has the highest surface area (about 195 m2/g) compared to the other two types of alumina (>195 m2/g) does not have a crystalline MoO3. The formation of crystalline MoO3 is not influenced by the acidity alumina. Based on the results of XRD, it is indicated that the supported alumina-3 NiMo catalyst (having the highest acid strength) shows that there is no presence of crystalline MoO3. Pore size distribution of support did not change significantly after the deposition of Ni and Mo oxides. Mechanical strength of support also affects the strength NiMo catalyst. Support alumina-3 which has the highest mechanical strength gives the mechanical strength of the highest NiMo catalyst.

165-172

Authors: Sri Hidayati, Natalia Gultom, Hestuti Eni

An experiment of sulfonation process of methyl ester to produce methyl ester sulfonates (MES) was caried out using waste palm methyl ester and sulfuric acid as sulfonating agent with variation of H2SO4 concentration (60% (K1), 70% (K2), dan 80% (K3)) and sulfonation time (60 minute (L1), 75 minute (L2) and 90 minute (L3)) using factorial on Randomized Complete Design Block. The experiment result showed the best sulfonation condition present in 80% H2SO4 concentration and sulfonation time of 90 minutes. The best characteristic of MES is produced showed surface tension of 27.35 dyne/cm, emulsion stability of 89.44%, acid value of 17.72 mg KOH/g and interfacial tension of 0.0361 dyne/cm at MES concentration of 2% in 10,000 ppm salinity water.

9-16

Authors: M. Faisal, Hiroyuki Daimon, Koichi Fujie

The behavior of heavy metals eluted from the wall of Ni/Fe-based alloy reactors after high-temperature and high-pressure water reaction were studied at temperatures ranging from 250 to 400oC. For this purpose, water and cysteic acid were heated in two reactor materials which are SUS 316 and Inconel 625. Under the tested conditions, the erratic behaviors of soluble metals eluted from the wall of Ni/Fe-based alloy in high temperature water were observed. Results showed that metals could be eluted even at a short contact time. The presence of air also promotes elution at sub-critical conditions. At sub-critical conditions, a significant amount of Cr was extracted from SUS 316, while only traces of Ni, Fe, Mo and Mn were eluted. In contrast, Ni was removed in significant amounts compared to Cr when Inconel 625 was tested. It was observed that eluted metals tend to increased under acidic conditions and most of those metals were over the limit of WHO guideline for drinking water. The results are significant both on the viewpoint of environmental regulation on disposal of wastes containing heavy metals, toxicity of resulting product and catalytic effect on a particular reaction.

25-32

Authors: Teguh Ariyanto, Imam Prasetyo, Rochmadi Rochmadi

Nanoporous carbons, due to high specific surface area, high pore accessibility, and relatively low cost, have been used as material electrode supercapacitors. In this work, the influence of pore structure of nanoporous carbons on the specific capacitance of supercapacitors was examined. Nanoporous carbons with several types of pore structure were prepared by carbonization of phenolic resin produced by polymeric condensation of phenolic compound with formaldehyde. Furthermore, ethylene glycol, as a filler, was added in the phenolic resin polymerization to increase the mesoporosity of nanoporous carbon. The nanoporous carbons produced were characterized for their surface morphology, specific internal surface area (BET method), and pore structure. Samples were used as electrode material in supercapacitor and specific capacitances were characterized by galvanostatic test using 30% KOH aqueous solution as electrolyte. The capacitance test of supercapacitors exhibited that increasing mesoporosity increase specific capacitance value of supercapacitors. The highest specific capacitance of 336 F/g was obtained by using mesoporous carbon produced by carbonization of resorcinol phenol formaldehyde ethylene glycol (C-RPFEG2) as electrode material of supercapacitors.

39-45

Authors: Tjukup Marnoto, Gogot Haryono, Dewi Gustinah, Fendy Artha Putra

Public awareness on using natural dyes has encouraged the extraction of tannins from putrimalu. Extraction was performed continuously using a Soxhlet apparatus. The parameter studied was the influence of solvent polarity on the amount of tannin and mass transfer coefficient. Tannin was extracted from ten grams of dried putrimalu plants using polar solvents (ethanol, acetone and methanol) and a non-polar solvent (n-hexane). Extraction is considered complete when the concentration of tannins in the liquid is no longer changing with time. Liquid samples were withdrawn every 20 minutes interval for tannin analyses using Thin Layer Chromatography (TLC). The results showed that the maximum concentration of tannins in the extract (g/mL) when extraction were performed using n-hexane was 0.0031, acetone (0.016), methanol (0.0274) and ethanol (0.044). From extract yield and mass transfer coefficient point of views, it can be concluded that the best solvent is ethanol. The relationship between tannin concentration in the ethanol 96% solvent and the time was expressed in term of mathematical equations CAL=1.046(1-e-0.0213t) with error was 3.6%. Where CAL is the concentration of tannins in the solvent (g/ml) and t is the extraction time (minutes).

51-60

Authors: Kusmiyati Kusmiyati, Puspita Adi Lystanto, Kunthi Pratiwi

Industrial wastewater may contain heavy metals such as Cu and Ag those are harmful to the environment if discharged without pretreatment. One of the methods to reduce heavy metals in wastewater is adsorption, to separate certain components from liquid to the surface of solids. Adsorption is a simple method, but most of the adsorbents are expensive, therefore a cheaper adsorbent is required to reduce the cost of the adsorption process. This work utilized bottom ash as an adsorbent. Bottom ash is a waste of combustion products in the coal industry, which contain potentially harmful materials. Activation of bottom ash was made by soaking in peroxide and continuing by heating at a temperature of 500oC. This study was aimed to determine the influence of process parameters (concentration, pH and processing time) to the percentage of amount heavy metals adsorbed, to study the equation isotherm adsorption using Langmuir and Freundlich models, and to calculate the kinetic constants of adsorption based on pseudo -first- order and pseudo-second-order kinetic model. The experiment was conducted in the batch system, where 10 grams bottom ash was mixed with 400 ml of synthetic waste. AAS was used to determine the heavy metals content in the waste solution. The results showed that bottom ash can be used to reduce heavy metals of Cu2+ and Ag+, the optimum condition when the concentration of 25 ppm under acidic conditions, bottom ash was able to adsorb Cu2+ metals ion by 62.79-80.25% at pH 4, and 65.54-85.98% at neutral pH with the same adsorption time of 300 min. For the ion metals Ag+, at acidic solution the metals ion can be adsorbed by 56.51-82.21%, while at neutral pH conditions 59.92-87.55%. Adsorption of bottom ash follows the model of Freundlich isotherm adsorption at acidic and neutral condition, the correlation coefficient (R2)obtained was 0.994 for Cu2+ metals ion and 0.984 for the Ag+ metals ion at acidic solution, whereas 0.986 for Cu2+ metals ion and 9.69 for the Ag+ metals ion at neutral pH. Kinetic model of second order rate describe the adsorption process well at acidic and neutral conditions. At the optimum conditions, the correlation coefficient (R2) of 0.998 for Cu2+ and 0.999 for the Ag+ at acidic solution, whereas 0.993 for Cu2+ and 9.998 for the Ag+ at neutral pH were obtained.

68-72

Authors: Meiny Suzery, Ely Kusniawati, Dwi Hudiyanti, Bambang Cahyono

Isolation of hyptolide has been done from Hyptis pectinata, and alkene group transformation through oxidation reactions using H3B: OEt2 to the isolated compound was also conducted. Product analyses were carried out using TLC, UV spectrometry, IR, and LC-MS. Pure crystal with melting point of 86-87oC was isolated. The yield was 1.75% (w/w). After analysing and compilating of spectroscopic data it was confirmed as hyptolide compound. Hydroboration of this compound (followed by hydrolysis using H2O2 under alkaline conditions) produce its alcohol derivatives, with 28.9% the percentage of transformation, it was demonstrated by LCMS data. IR spectrum at 3600cm-1, confirming the replacement of hydroxyl bond by alkene. Regioselectivity of addition reaction is proposed through simulation with Chem Office. The reaction product was suspected as 6-hydroxy-7-(6-oxo-3,6-dihydro-2H-pyran-2-yl) heptane-2,3,5-tryil triacetate. Extension of reaction time to 24 hours, has increase hydroboration product to 78.3%. This research has opened other studies of natural materials in accordance to the roadmap set.

79-85

Authors: Indro Sumantri, Sumarno Sumarno, Norma Afiati

Proses konvensional untuk mengolah limbah cair industri urea biasanya menggunakan proses alga mikro atau bakteri heterotropik nitrifikasi-denitrifikasi. Proses alga mikro dapat menggunakan berbagai jenis alga mikro. Keuntungannya adalah murah karena hanya memerlukan nutrien P sedikit tetapi tidak dapat digunakan untuk menyusutkan amoniak. Proses nitrifikasi-denitrifikasi bakteri heterotropik memerlukan asupan karbon yang tinggi sehingga pengolahan menjadi mahal. Tujuan saat ini untuk penelitian adalah untuk mempelajari kombinasi yang potensial untuk proses alga mikro jenis tertentu dengan proses nitrifikasi-denitrifikasi ototrofik. Jenis alga mikro yang digunakan dalam proses alga mikro mempunyai kemampuan baik untuk penyusutan amoniak atau tahan dalam konsentrasi amoniak tinggi. Proses nitrifikasi-denitrifikasi ototrofik menggunakan bakteri nitrifikasi/lumpur sebagai biokatalis. Lumpur nitrifikasi awal adalah lumpur aktif kolam aerasi unit pengolahan limbah cair industri partikel board Pengayaan dan pembibitan lumpur nitrifikasi dilakukan dalam konsentrasi amoniak yang tinggi dan kondisi ototrofik. Berdasarkan penelitian, pengayaan dan pembibitan alga mikro yang mempunyai kemampuan untuk penyusutan amoniak dan tahan konsentrasi amoniak yang tinggi mudah. Evaluasi substrat pembatas penghambat amonium terhadap pertumbuhan alga tidak terbukti. Tujuh variabel yang dipilih lewat penapisan adalah : MLSS, waktu tinggal, konsentrasi NH3-N, laju aerasi, kadar CaCO3, nutrien mikro, rasio N:P. Variabel yang berpengaruhadalah konsentrasi NH3-N, laju aerasi, kadar CaCO3.