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All Journal Jurnal Agronomi Indonesia (Indonesian Journal of Agronomy) IPTEK Journal of Proceedings Series IPTEK The Journal for Technology and Science Journal of Engineering and Technological Sciences
Gede Wibawa
Department Of Chemical Engineering, Faculty Of Industrial Technology, Sepuluh Nopember Institute Of Technology (ITS), Kampus ITS Sukolilo, Surabaya 60111, Indonesia
Agriculture, Biological Sciences & Forestry Computer Science & IT Economics, Econometrics & Finance Engineering

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CO2 Frost Phenomenon for Binary System of Methane-Carbon Dioxide Mixtures Wibawa, Gede; Mustain, Asalil; Sumarno, Sumarno; Gunawan, Setiyo
Journal of Engineering and Technological Sciences Vol 47, No 6 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (344.868 KB) | DOI: 10.5614/j.eng.technol.sci.2015.47.6.2

Abstract

In the present study, the CO2 frost phenomenon of CH4-CO2 mixtures has been observed for the rational design of CO2 removal from natural gas using a controlled freeze out area. The CO2 frost conditions were estimated using the ZNE method and process simulation software (Aspen HYSYS® v7.3). The experiment was carried out using a double pipe heat exchanger (DPHE) with the concentration of CO2 in the gas mixture at 5 and 10% and pressure of the gas mixture from 1 to 20 bar. The equilibrium temperature predictions of the ZNE method and the process simulation software only had a slight difference, with a magnitude deviation of less than 1% for pressures below 20 bar and 3% for pressures in the range of 20-30 bar, respectively. In the experimental study, CO2 frost formation was detected at pressures of 1, 5, 10 and 20 bar. The locations of the initial CO2 frost formation were determined using a pressure drop indicator associated with the predicted frost temperatures obtained from the ZNE method and the process simulation software. For all studied variables, the locations of initial CO2 frost formation were found at 0.887-1.531 m from the inlet.
Prediction of Ternary Vapor-Liquid Equilibria for Alcohols + Glycerol + Water Systems to Enhance the Quality of Glycerol as Biodiesel Side Product D. Setiawati, Eviana; Mustain, Asalil; Wibawa, Gede
IPTEK Journal of Proceedings Series No 1 (2015): 1st International Seminar on Science and Technology (ISST) 2015
Publisher : Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j23546026.y2015i1.1172

Abstract

Fossil fuels as the primary energy resources around the world cause significant negative effect on atmosphere. Recently, biodiesel, which primarily produced from renewable resources, has received great attention because of its environmental benefits. Higher chain of alcohols, such as butanol, may be used as solvent to produce biodiesel with glycerol as byproduct. In order to enhance the quality of glycerol as biodiesel side product which meets food and pharmaceutical standards, vapor-liquid equilibria (VLE) data for ternary systems consisting of 1-butanol, 2-methyl-1-propanol, glycerol and water are required to design and optimize the separation process of glycerol. In this work, the prediction of ternary VLE for (1-butanol / 2-methyl-1-propanol + glycerol + water) using UNIFAC model were determined at various temperatures and compositions and compared with the experimental data giving Average Absolute Deviations (AAD) less than 5.7%. The results indicated that UNIFAC was a reliable model for phase equilibria predictions in the mixtures containing of glycerol
Mixing Rule of Sanches-Lacombe Equation of State for Prediction of Solvent Solubility in Polymer Solution Wibawa, Gede
IPTEK The Journal for Technology and Science Vol 19, No 3 (2008)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v19i3.147

Abstract

In this work, mixing rule of Sanches-Lacombe equation of state (SL-EoS) was developed for estimating vapor-liquid equilibria of solvent-polymer systems or solubility of solvent in polymer solutions. The model was derived by matching excess Gibbs energy of Sanches-Lacombe equation of state and that of group contribution model at zero pressure. Present model can be applied to wide range of pressure. In addition, this model covers systems with various molecular interactions, since functional group interaction parameters of UNIFAC-FV and UNIFAC-ZM models have been available for various groups.
Kombinasi Optimal cara Olah Tanah dan Tingkat Pengapuran untuk Pola Tumpangsari Jagung di antara Karet pada Tanah Podzolik Merah Kuning Wibawa, Gede; Suryaningtyas, Heru
Jurnal Agronomi Indonesia (Indonesian Journal of Agronomy) Vol. 29 No. 3 (2001): Buletin Agronomi
Publisher : Indonesia Society of Agronomy (PERAGI) and Department of Agronomy and Horticulture, Faculty of Agriculture, IPB University, Bogor, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1419.021 KB) | DOI: 10.24831/jai.v29i3.1543

Abstract

Technical modification of rubber based intercropping system are still needed due to the appearance of various problems, either bio-physical or socio-economie factors. At different areas, where labour is limited, substitution of  manual tillage and manual seeding with mechanical equipment and manual weed control with chemical control has to be taken into account. Research on rubber based intercropping, combining two tillage systems. Conventional or full tillage, where soil was plowed and harrowed 2 and 2 times respectively,. and reduced tillage where soil tillage was done only one plowing and one harrowing and four liming levels atintercrop rows at 20 cm with (maize, variety of C7) was carried out in Sembawa Research Institute since 1998. The presented data were collected tillage system and liming dose was observed, however the grain yield difference was reduced up to 22%. During dry season cowpea (Vigna anguikulata), planted after maize, produced 870 kg/ha. The cost of production of cropping maize as rubber intercrop using full tillage system at optimal liming level was about Rp. 2,1 million. If the grain price is Rp. 1200/kg then the break-even point will be reached at grain yield of 1750k g/Ha. Rubber growth of IRR 39 clone, a latex and timber clone, was very good. Until 13 months stem diameter was  not affected by tillage systems and levels of liming for intercrop. Key words: Intercropping, Rubber, Maize, Cowpea, Soil tillage, Liming, Ultisol
Co-Authors Asalil Mustain D. Setiawati, Eviana Heru Suryaningtyas Setiyo Gunawan Sumarno .