March 25, 2008 at 8:48 am (Catalyst, Plasma chemistry)
Antonius Indarto, Jae-Wook Choi, Hwaung Lee and Hyung Keun Song
Journal of the Chinese Institute of Chemical Engineers, 39(1), 23-28
Abstract:
The hydrogen fuel cell is a promising option as a future energy resource; however, the nature of the gas is such that the conversion process of other fuels to hydrogen on board is necessary. Among the raw fuel resources, methane could be the best candidate as it is plentiful. In this experiment, the possibility of producing hydrogen with less carbon formation from methane by a dielectric barrier discharge (DBD) was investigated. Without the addition of a catalyst, the formation of hydrogen reached between 30% and 35% at methane residence time of 0.22 min and supplied powers in the range of 60–130 W. The hydrogen selectivity increased at higher supplied power, but the process efficiency, defined as a ratio of the produced hydrogen to the supplied power, decreased slightly. In order to boost the hydrogen production with less carbon formation, a mixed oxide catalyst of zinc and chromium was added to the reactor. It was shown that the production of hydrogen was ca. 40% higher than the non-catalytic plasma process.
Keywords: Plasma; Dielectric barrier discharge; Methane; Hydrogen production
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March 25, 2008 at 8:43 am (Catalyst, Review)
Antonius Indarto, Jae-Wook Choi, Hwaung Lee and Hyung Keun Song
Journal of Rare Earths, 26(1), 1-6
Abstract:
C1 chemistry based on synthesis gas, methane, and carbon dioxide offers many routes to industrial chemicals. The reactions related to the synthesis of gas can be classified into direct and indirect approach for making such products, such as acetic acid, dimethyl ether, and alcohol. Catalytic syngas processing is currently done at high temperatures and pressures, conditions that could be unfavorable for the life of the catalyst. Another issue of C1 chemistry is related to the methane-initiated process. It has been known that direct methane conversions are still suffering from low yields and selectivity of products resulting in unprofitable ways to produce products, such as higher hydrocarbons, methanol, and so on. However, many experts and researchers are still trying to find the best method to overcome these barriers, for example, by finding the best catalyst to reduce the high-energy barrier of the reactions and conduct only selective catalyst-surface reactions. The application of Yttria-Stabilized Zirconia (YSZ) and its combination with other metals for catalyzing purposes are increasing. The existence of an interesting site that acts as oxygen store could be the main reason for it. Moreover, formation of intermediate species on the surface of YSZ also contributes significantly in increasing the production of some specific products. Understanding the phenomena happening inside could be necessary. In this article, the use of YSZ for some C1 chemistry reactions was discussed and reviewed..
Keywords: C1 chemistry; methane; synthesis gas; methanol; yttria-stabilized zirconia; catalyst; oxygen storage; rare earths
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March 25, 2008 at 8:33 am (Plasma chemistry)
Antonius Indarto, Nowarat Coowanitwong, Jae-Wook Choi, Hwaung Lee and Hyung Keun Song
Fuel Processing Technology, 89(2), 214-219
Abstract:
Methane conversion by plasma offers a promising route to produce higher value-added products. As plasma reaction is a relatively complex process, kinetic modeling is necessary to obtain a general pattern of the complex interaction on the basis of chemical reaction and products. In this paper, we present a method to obtain the kinetic rate coefficient (k) from the experimental data. Although plasma reaction was classified as chemically complex interaction, the reactions showed a certain pattern of the mechanism. In pure methane injection, the decomposition of methane by plasma could initiate coupling reactions and produce C2H6, C3H8, and C4H10. Dehydrogenation of C2H6 into C2H4 and then to C2H2 could be clearly seen by the higher value of the reaction rate constant of C2Hn + 2 to C2Hn − 2. Using the rate constant values (k) obtained by this method, the pathways of the methane conversion by a dielectric barrier discharge can be drawn.
Keywords: Plasma; Dielectric barrier discharge; Methane; Kinetic reaction
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March 24, 2008 at 7:34 pm (Plasma chemistry)
Antonius Indarto, Jae-Wook Choi, Hwaung Lee and Hyung Keun Song
Journal of Chinese Chemistry Society, 54 (4), 823-828
Abstract:
A series of metal catalysts was used for methane conversion to higher hydrocarbons and hydrogen in a dielectric barrier discharge. The main goal of this study is to identify the metal catalyst components which can influence the reactions in room-temperature plasma conditions. The catalysts supported by γ-Al2O3 and zeolite (ZSM 5x) were prepared by the incipient wetness method with solutions containing the metal ions of the second component. Among the catalysts tested, only Pt and Fe catalysts showed a unique result of catalytic reaction in a reactor bed packed with glass beads.
Keywords: Plasma; Dielectric barrier discharge; Metal catalyst; Methane conversion
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October 21, 2007 at 7:57 pm (General chemistry, Physical chemistry)
I wrote this title as rarely we hear or use the value of chemical potential for chemistry purposes. This became a hot topic (one of the most discussed) in the 2007 IUPAC conggress in Torino. Chemical potetial is believed as a part of physical and thermodinamical chemistry but less favourable than other terms, such as: entropy, enthalphy. Even, most of students probably never hear the use of this value to calculate their thermidinamic problem. It is more to the ‘ego’ of chemists to describe their ‘own worlds’ (just an opinion). Read the rest of this entry »
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July 29, 2007 at 12:19 am (Computational chemistry)
Taking from the name of the above software, it will be recognized as the software used for calculating the kinetics of chemical process. However, the next word ’simulator’ could be taken account as the most important part about what this software can do. This is a simulator program (only) which allows you to calculate simultaneously a set of differential equation of reaction rates. Unfortunately, this software does not have such a ‘databank’ about the kinetic. So, you have to put it by yourself. Read the rest of this entry »
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July 21, 2007 at 12:02 am (Computational chemistry)
For everyone who works in reaction kinetic and pathway, they will be very familiar with this software. Kintecus is known as a program to simulate the chemical kinetics of combustion, biological, nuclear, and air atmosphere in spreadsheet files. Putting spreadsheet as the basis of the interface is nice as most of people are familiar enough with Excel MS. Although it is written not necessary to have MS Excel, it could be better to have at least Excel viewer. The module of the program is activated via macros, so you have to set ‘low’ level of secuirity of your MS Excel. Read the rest of this entry »
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July 8, 2007 at 3:06 am (Computational chemistry, Gaussian)
In reaction kinetic calculation, the transition structure is necessary to calculate the kinetic rate constant. In Gaussian calculation, it is known by the existence of single negative value of frequency. So, it could be TS of rotation, conformation, addition, insersion, and so on. Using Molden software, you can nicely see what happen to the molecule in the negative frequency. I browsed one of the mailing list, and I got a nice explanation about the scientific term of negative frequency written by Christopher Crammer: Read the rest of this entry »
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July 8, 2007 at 2:26 am (Uncategorized)
Trouble with many pdf file that you have collected? These proposed softwares could be help you to manage numerous pdf file especially collected papers. Read the rest of this entry »
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July 8, 2007 at 1:55 am (Gaussian)
Here, I will put continuously the error messages of Gaussian program and its solution. I collect all these from the internet, mailing list, and also my experiences when I use Gaussian. Read the rest of this entry »
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