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Journal : Makara Journal of Technology

Effects of Ph on Calcium Carbonate Precipitation Under Magnetic Field Saksono, Nelson; Yuliusman, Yuliusman; Bismo, Setijo; Soemantojo, Roekmijati; Manaf, Azwar
Makara Journal of Technology Vol 13, No 2 (2009)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

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Abstract

Magnetic field effect on CaCO3 precipitation is the key parameter in evaluating the effectiveness of Anti-scale Magnetic Treatment (AMT). The purpose of this study was to investigate magnetic fields influence on CaCO3 precipitation in high and low super-saturated CaCO3 solution by varied pH CaCO3 solution using circulation flow fluid system. The observation results in the high super saturated solution (pH 8.5) showed the increase of precipited CaCO3 in magnetized solutions compared to those in non-magnetic solution during circulation process. In the low super-saturated CaCO3 solution (pH 6.4) it was found that magnetic treatment increased CaCO3 precipitation after circulation process. In high super-saturated solution, magnetic field strengthens ion interactions, which reduce precipitation during circulation process. However, in low super-saturated CaCO3 solution, magnetic field weakens hydrate ion interaction which indicated by decreasing of the conductivity of solution. It increases the precipitation of CaCO3 after the circulation of magnetization process has completed.
Kinetic Model For Triglyceride Hydrolysis Using Lipase:Review Hermansyah, Heri; Wijanarko, Anondho; Dianursanti, Dianursanti; Gozan, Misri; Wulan, Praswasti P. D.K; Arbianti, Rita; Soemantojo, Roekmijati W.; Utami, Tania Surya; Yuliusman, Yuliusman; Kubo, Momoji; Shibasaki-Kitakawa, Naomi; Yonemoto, Toshiy
Makara Journal of Technology Vol 11, No 1 (2007)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

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Abstract

Triglyceride hydrolysis using lipase has been proposed as a novel method to produce raw materials in food and cosmetic industries such as diacylglycerol, monoacylglycerol, glycerol and fatty acid. In order to design a reactor for utilizing this reaction on industrial scale, constructing a kinetic model is important. Since the substrates are oil and water, the hydrolysis takes place at oil-water interface. Furthermore, the triglyceride has three ester bonds, so that the hydrolysis stepwise proceeds. Thus, the reaction mechanism is very complicated. The difference between the interfacial and bulk concentrations of the enzyme, substrates and products, and the interfacial enzymatic reaction mechanism should be considered in the model.
Performance of Hollow Fiber Membrane Gas-Liquid Contactors to Absorb CO2 Using Diethanolamine (Dea) as a Solvent Kartohardjono, Sutrasno; Nata, Pan; Prasetio, Eko; Yuliusman, Yuliusman
Makara Journal of Technology Vol 13, No 2 (2009)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

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Abstract

This study uses DEA solution to absorb CO2 from the gas flow through the hollow fiber membrane contactors. This study aims to evaluate the performance of hollow fiber membrane contactors to absorb CO2 gas using DEA solution as solvent through mass transfer and hydrodynamics studies. The use of DEA solution is to reduce the mass transfer resistance in the liquid phase, and on the other side, the large contact area of the membrane surface can cover the disadvantage of membrane contactors; additional mass transfer resistance in the membrane phase. During experiments, CO2 feed flows through the fiber lumens, while the 0.01 M DEA solution flows in the shell side of membrane contactors. Experimental results show that the mass transfer coefficients and fluxes of CO2 increase with an increase in both water and DEA solution flow rates. Increasing the amount of fibers in the contactors will decrease the mass transfer and fluxes at the same DEA solution flow rate. Mass transfer coefficients and CO2 fluxes using DEA solution can achieve 28,000 and 7.6 million times greater than using water as solvent, respectively. Hydrodynamics studies show that the liquid pressure drops in the contactors increase with increasing liquid flow rate and number of fibers in the contactors. The friction between water and the fibers in the contactor was more pronounced at lower velocities, and therefore, the value of the friction factor is also higher at lower velocities.
CO2 Absorption from Its Mixture with CH4 or N2 through Hollow Fiber Membrane Contactor using Water as Solvent Kartohardjono, Sutrasno; Anggara, Anggara; Subihi, Subihi; Yuliusman, Yuliusman
Makara Journal of Technology Vol 11, No 2 (2007)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

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Abstract

Hollow fiber membrane contactors have been widely used as gas-liquid contactors recently such as in the CO2 absorption process from gas stream. This research aims to evaluate the effectiveness of hollow fiber membrane contactor to absorb CO2 from its mixture with CH4 or N2 using water through mass transfer and hydrodynamic tests. There are 3 membrane modules used in this research with shell diameter of 1.9 cm, length of 40 cm, outer fiber diameter of 2.7 mm and fiber number in the contactors of 10, 15 and 20. Liquid flow rates in the hollow fiber membrane contactors are varied in this research. Research results show that mass transfer coefficients in the membrane contactor increase with increasing liquid flow rate and decrease with increasing fiber number in the contactor. Flux of CO2 into water can achieve 1.4x10-9 mol CO2 /m2.s and mass transfer coefficients can achieve 1.23 x 10-7 m/s. Meanwhile, hydrodynamic test results show that water pressure drop in the membrane contactors increase with increasing fibernumber in the contactors.