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ASEAN Journal of Chemical Engineering

AJChE
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Published by Universitas Gadjah Mada

ISSN : 26555409 EISSN : 26555409 DOI : https://doi.org/10.22146/ajche.52004

Core Subject : Science, Engineering,

Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry

The ASEAN Journal of Chemical Engineering publishes papers on Chemical Engineering, specifically but not limited to the areas of thermodynamics, reaction kinetics, transport phenomena, process control, environment, energy, biotechnology, corrosion, separation science, powder technology, materials science, and chemical engineering education

Arjuna Subject : Teknik Kimia (semua kategori) - Kimia Proses dan Teknologi

Articles 372 Documents

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Second Generation of Biodiesel Production from Indonesian Jatropha Oil by Continuous Reactive Distillation Process Arief Budiman; Ratna D Kusumaningtyas; Sutijan Sutijan; Rochmadi Rochmadi; Suryo Purwono
ASEAN Journal of Chemical Engineering Vol 9, No 2 (2009)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

The batch process of biodiesel production deals with problems related to the labor and separation cost since it is slow, entailing several separation steps, labor intensive, and not suitable for a very large-scale production. Therefore, a second generation process technology for biodiesel should be developed. In this work, a continuous transesterification using reactive distillation was proposed. The goal was to bring in a more efficient reactor system by combining chemical reactions and separation simultaneously in one unit. In this work, a laboratory-scale Reactive Distillation was applied for the biodiesel synthesis from the Indonesian refined jatropha oil in the presence of NaOH catalyst. The experimental investigation demonstrated the effects of the temperature, catalyst loading, and molar ratio of the reactants. The best result was achieved on the process conducted at the reaction temperature of 65 ºC with molar ratio of methanol to triglycerides of 10:1 and catalyst loading of 0.75% w/ w oil. The reaction conversion was 94.83% and methyl ester content of the product was 99.27%. The fuel characteristic of biodiesel agreed with the Indonesian national standard and ASTM specification.

Kinetics of Ferrous Sulfate Catalytic Oxidation from Dissolved Iron Waste in Sulfuric Acid Hary Sulistyo; Suprihastuti Sri Rahayu; Wahyudi Budi Sediawan; Sarto Sarto; Takdir Syarif
ASEAN Journal of Chemical Engineering Vol 9, No 2 (2009)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

Iron waste was dissolved in a sulfuric acid to form a concentrated FeSO4- H2SO4 solution This research was conducted by catalytic oxidation of ferrous sulfate using manganese dioxide as catalyst to form a ferric sulfate. Catalytic oxidation reaction using a catalyst of manganese dioxide is a three phase heterogeneous reaction. This reaction kinetics is quite complex. This study aims to develop a mathematical modeling of reaction kinetics for three phases, gas, liquid and solid. Oxidation was undertaken on the condition of isothermal and isobaric in the threeneck flask as reactor. Experiment was run in the temperature range of 313 K to 363 K and catalyst concentration of 4.16 10 -3 gL-1 to 25 10 -3 gL-1.Results indicated that the oxidation rate increased with the increase of temperature and catalyst concentration. Reaction kinetics can be approached with quasi steady state model and chemical reactions on the surface of the catalyst are a step controls the reaction kinetics. The relation between reaction rate constant and temperature in the following Arrhenius form:kR = 2182exp (-17613/RT),L g.eq-1min-1 Manganese dioxide as catalyst can increase a reaction rate and reduce the activated energy which can be expressed in the following equation E = 20129.025exp(-0.0472mk),Jmol-1 Activated energy was found from 14414 Jmol-1to 19747 Jmol-1 and maximum ferrous sulfate conversion was of 97.20%. Those values were similar result with the literature available.

H2-poor bio-syngas in Fischer-Tropsch synthesis over un-promoted and rhenium promoted alumina-supported cobalt catalysts: Effect of water addition Dewi Tristantini; Borje Gevert
ASEAN Journal of Chemical Engineering Vol 9, No 1 (2009)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

The effect of water addition on Fischer-Tropsch synthesis (FTS) over 12%Co/Al2O3 and 12%Co-0.5%Re/Al2O3 catalysts was investigated in a fixed bed reactor with model mixtures of biomass-derived syngas (bio-syngas). The bio-syngas model mixtures consist of H2 and CO of different molar H2/CO-ratios (1.0, 1.5 and 2.1). The FT-reaction requires a H2/CO molar ratio of approximately 2.1 above the catalyst surface. For the ratios lower than 2.1, an in situ water-gas shift (WGS) activity is desired in order to increase the H2/CO-ratio. However, the studied catalysts had quite low WGS activities. The addition of water slightly increased the WGS activity for all types of bio-syngases and for both catalysts. The highest WGS activity was found for the un-promoted Co-catalyst at the inlet H2/CO-ratio = 1.0. Water addition also results in an increase in selectivity to C5+ and a decrease in selectivity to CH4 . Interestingly, for both of catalysts the selectivity to C5+ and CH4 were rather similar for inlet H2/CO-ratios of 2.1 and 1.5, while the highest selectivity to C5+ and the lowest selectivity to CH4 were also found for the inlet ratio = 1.0. All catalysts were deactivated by water addition but the catalyst activity is partly recovered in H2/CO-ratio inlets = 1.0 and 1.5. The Co/Al2O3 was affected by water more severely in H2/CO ratios = 2.1. The Re-promoted Co catalyst was considerably more active and selective to longer hydrocarbons than the un- promoted one. The conclusion of this study is that in order to utilize the advantages of a bio-syngas with a low H2 content (higher selectivity to C5+, lower selectivity to CH4, no WGS-unit needed prior to FT-reactor), the catalyst must possess a much higher WGS activity than the ones studied.

Regeneration, MDA, Mo carbide, zeolite, aromatic, coke Chandra Mohan Sinnathambi
ASEAN Journal of Chemical Engineering Vol 9, No 1 (2009)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

Methane dehydro-aromatization (MDA) is a one-step conversion of methane to aromatics under non-oxidative condition in the presence of Mo-modified HZSM-5. The main drawback of MDA reaction is the rapid deactivation of the Mo carbide catalyst by coking. For catalyst stability and efficiency, a suitable and economical catalytic regeneration system is necessary. The present study investigates the regainability of catalyst activity by in-situ regeneration of spent 3wt% -Mo/HZSM-5 catalyst in air. Encouraging results is observed when 5% oxygen at a GHSV of 4800h-1 over 1 hour was used. The main drawback is coke is favored over aromatic product.

One Dimensional Mathematical Model of Re-Ignition Characteristics Tri Poespowati
ASEAN Journal of Chemical Engineering Vol 9, No 1 (2009)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

Re-ignition of a wood-based object essentially comprises three overlapping phases; these are the heat-up phase, the extinguishment phase, and the re-heat-up phase. A one-dimensional mathematical model was developed in this study to simulate multiple consecutive ignitions associated with re-ignition process within a porous material. The model focuses on the treatment of heat transfer in porous media that is assumed to be one-dimensional within a homogeneous sample. The effect of porosity is incorporated through the inclusion of an effective thermal conductivity. Our experience indicates that the ignition temperatures and ignition delay times obtained from this approach are in good agreement with relevant experimental data.

Influence of Oxygenation on Granulation in Anaerobic Wastewater Treatment Soeprijanto Soeprijanto; K. Brighton
ASEAN Journal of Chemical Engineering Vol 9, No 1 (2009)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

The emphasis of this study was to put on the ability of bacteria to form granules in anaerobic wastewater treatment. This direction was taken mostly because the success of wastewater treatment in such systems as Upflow Anaerobic Sludge Blanket (UASB) depends on how long the biomass is retained, and this is a function of adhesion of bacteria to reach other to form well-settling granular sludge. The granular sludge will remain in the reactor and will be exposed to the continuous supply of nutrients (wastewater) which is injected into it. The wastewater used in this study was synthetic. It consisted of molasses dissolved in water (100%), and a mixture of molasses and peptone dissolved in water (20 % and 80 %, respectively). Several factors or parameters influence bacteria to form good granules and improve the performance of the digesters. The effects of oxygen on the anaerobes, and the extent to which it acts as an inhibitor or toxic was studied. This was found to be both advantageous and disadvantageous.

Mathematical Model and Advance Control for Activated Sludge Process in Sequencing Batch Reactor Ahmmed S Ibrehem; Mohamed Azlan Hussain
ASEAN Journal of Chemical Engineering Vol 9, No 1 (2009)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

This paper presents the results of a modeling and simulation study of an activated sludge process in a sequencing batch reactor (SBR), with emphasis on total nitrogen removal. This study focuses on the effect of dissolved oxygen (DO) and effluent chemical oxygen demand (COD). Neural-network based redictive controller (MPC) is implemented to control the system for the DO set point and give better and acceptable results when compared with the conventional PID controller

Kinetics of Mass Transfer, Colour, Total Polyphenol and Texture Change of Manilkara Zapota During Convective Air Drying Chien Wha Chong; Chung Lim Law; Michael Wha Cloke; Luqman Chuah Abdullah; Wan Ramli Wan Daud
ASEAN Journal of Chemical Engineering Vol 9, No 1 (2009)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

The effects of air temperature and product size on drying kinetics, retained total polyphenol content (TPC), hardness kinetics and total colour change (.E) kinetics of ciku (Manilkara zapota) were investigated. In addition, five terms of the theoretical model were used to estimate the effective diffusivity values during drying at temperatures from40OC to 70OC. The drying rates of dried ciku were increased with increasing temperature and decreasing product size. It was found that hardness of ciku dried at temperature higher than 60OC increased significantly, when the moisture content was reduced toless than 0.5 g H2O/g DM (dry basis). In terms of nutritional value, the retained total polyphenol content (TPC) of dried ciku in hot air drying also increasing with temperature. The highest retained TPC was 141 mg GAE/ 100g of samples, which can be obtained from drying at 70OC.

Kinetic Study of Esterification of Free Fatty Acid in Low Grade Crude Palm Oil using Sulfuric Acid Satriana Satriana; Muhammad Dani Supardan
ASEAN Journal of Chemical Engineering Vol 8, No 1 & 2 (2008)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

The kinetics of the esterification of free fatty acids (FFA) in low grade crude palm oil (CPO) with methanol was studied. In this work, the effects of operational 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. The experimental results were found to fit a first-order kinetic law. The influence of temperature on the kinetic constants was determined by fitting the results to the Arrhenius equation.

Adsorption of CO, CO2 and H2 in Silicalite-1: measurements and simulations Sang Kompiang Wirawan; Martin Petersson; Derek Creaser
ASEAN Journal of Chemical Engineering Vol 8, No 1 & 2 (2008)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

Single component and mixture adsorption of CO2, CO and H2 in Silicalite-1 was studied with the step response experiments and through molecular simulations. Experiments were performed at 323.15, 373.15 and 473.15 K, and in the pressure range 10.13 to 81.06 kPa. CO2 adsorption was favored over CO during all studied conditions. The adsorption enthalpies were -24.3 and -13.5 kJ/mol for CO2 and CO respectively. Adsorption simulations were performed using the Grand Canonical Monte Carlo method. A new zeolite framework potential was derived, and was shown to give good agreement with the experimental results. The major reason for the higher saturation loading of CO2 compared to CO is however the stronger sorbate-zeolite attraction for CO2. The affinity for CO2 also causes a decrease in the adsorbed molar fraction of CO due to the competition with CO2.

Page 15 of 38 | Total Record : 372

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Home Page

OAI Link

Editorial Team

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Contact Name Ari Pramudyantoro

Contact Email ajche.ft@ugm.ac.id

Phone +62274555320

Journal Mail Official ajche.ft@ugm.ac.id

Editorial Address Jln. Grafika No. 2 Kampus UGM Yogyakarta Indonesia 55281

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Abstract

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Contact Name
Ari Pramudyantoro

Contact Email
ajche.ft@ugm.ac.id

Phone
+62274555320

Journal Mail Official
ajche.ft@ugm.ac.id

Editorial Address
Jln. Grafika No. 2 Kampus UGM Yogyakarta Indonesia 55281

Location
Kab. sleman,

Daerah istimewa yogyakarta

INDONESIA