• Journal of Energy Engineering
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• v.12 no.3
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• pp.231-240
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• 2003

Reactivity of Char-CO$_2$ gasification of five coals for power generation was investigated with PTGA in the temperature range 850∼1000$^{\circ}C$ and the pressure range 0.5∼2.0 MPa. The effect of coal rank, initial char characteristics and pressure on the reaction rate was evaluated for five chars. The reactivity of low lank coal char was better than that of high rank coal char, and this could be explained with the initial pore structure and surface area of char. Meso/macro-pores of char seems to markedly affect char reactivity by way of providing channels for diffusion of reactant gas into the reactive surface area. For the range of tested pressure, the reaction rate is proportional to CO$_2$ partial pressure and the reaction order ranges from 0.4 to 0.7 for five chars. The effect of total pressure on the reaction rate was small, and kinetic parameters, based on the unreacted core model, were obtained for five chars.

• Journal of Energy Engineering
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• v.13 no.1
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• pp.82-91
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• 2004

In order to utilize inorganic components in coal and wastewater sludge as an environmentally stable material, slag-forming is considered as one of the suitable methods better than producing as an ash. Coal slag that was produced by gasification as well as the slag made from wastewater sludge by incineration or melting process have been analyzed with the viewpoint of recyclability. Slags produced by water quenching exhibited a cracked shape that has a size of few millimeters with sharp edges. Slags contain the unburned carbon content below 0.15％ and expose mostly amorphous structural characteristics. Analysis results in the extraction of heavy metal compounds demonstrate that both slags from coal and wastewater sludge could be utilized as a safe recycle material even with a Japanese environmental regulation that is ten times more stringent than the current Korean standard. Slags from coal and wastewater sludge show significant differences in contents of each heavy metal compound. Since the future trend of environmental regulation shifts to the control of total content for each heavy metal compound, proper mixing of slags that contain different heavy metal contents might be an option for manufacturing recycle materials.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.8
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• pp.865-871
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• 2012

Because of the increasing cost of oil and natural gas, energy production technologies using coal, including synthetic natural gas (SNG) and integrated gasification combined cycle (IGCC), have attracted attention because of the relatively low cost of coal. During the early stage of a project, the developer or project owner has many options with regard to the selection of a gasifier. In particular, from the viewpoint of feasibility, the gasifier is a key factor in the economic evaluation. This study compares the technical aspects of gasifiers for a real SNG production project in an early stage. A fixed-bed slagging gasifier, wet-type entrained gasifier, and dry-type entrained gasifier, all of which have specific advantages, can be used for the SNG production project. Base on a comparison of the process descriptions and performances of each gasifier, this study presents a selection guideline for a gasifier for an SNG production project that will be beneficial to project developers and EPC (Engineering, Procurement, Construction) contractors.

• Journal of the Mineralogical Society of Korea
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• v.23 no.3
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• pp.219-225
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• 2010

Optimal grinding condition was examined by changing only the size of screen opening with fixing other factors to produce coal fines of particle sizes required for circulating fluidized bed gasifier. At least 85 wt% of the coal particles should fall into the size range of 0.045~1.0 mm for efficient gasification. In this study, hammer mill was used to grind Chinese low rank lignite coal following grinding condition designed by Taguchi method. The analysis of signal to noise ratio showed that optimum grinding condition for the gasifier was 3 mm in primary screen size and 1.3 mm in secondary screen size on the 95% level of significance.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.05a
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• pp.227-234
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• 2002

With the increasing environmental consideration and stricter regulations, gasification of waste is considered to be more attractive technology than conventional incineration for energy recovery as well as material recycling. The experiment for combustible waste mixed with plastic and cellulosic materials was performed in the fixed bed gasifier to investigate the gasification behavior with the operating conditions. Waste pelletized with a diameter of 2~3cm and 5cm of length was gasified at the temperature range of 1100~145$0^{\circ}C$. It was shown that the composition of H$_2$ was in the range of 30~40% and CO 15~30% depending upon oxygen/waste ratio. Casification of waste due to thermoplastic property from mixed plastic melting and thermal cracking shows a prominent difference from that of coal or coke. It was desirable to maintain the top temperature up to foot to ensure the mass transfer and uniform reaction through the packed bed. As the bed height was increased, the formation of H$_2$ and CO was increased whilst $CO_2$ decreased by the char-$CO_2$ reaction and plastic cracking. From the experimental results, the cold gas efficiency was around 61% and heating values of product gases were in the range of 2800~3200㎉/Nm3.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2010.04a
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• pp.201-201
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• 2010

• Journal of the Korean Professional Engineers Association
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• v.39 no.5 s.188
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• pp.20-24
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• 2006

The energy of 97% consumed by our country depends on it's import from foreign market. This article covers hydrogen, fuel-cell, coal liquefaction gasification energy, and solar, wind, photovoltaic, hydro power, ocean, waste, geothermal, bio energy that is renewable energy, and so on, which are new-generation energy sources, increasing the concern on new & renewable source of enenrgy in future.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2006.05a
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• pp.189-193
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• 2006

• Magazine of RCR
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• v.16 no.3
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• pp.59-65
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• 2021

• Journal of Energy Engineering
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• v.23 no.1
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• pp.58-66
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• 2014

Catalytic gasification of a low rank coal- Inner Mongolian lignite has been carried out with carbon dioxide. The gasification reactions were performed in a thermogravimetric analyzer at temperatures of $600^{\circ}C$ to $900^{\circ}C$. The kinetic parameters were evaluated using three different gas-solids reaction models and the prediction ability of each model were compared. Among the models evaluated, the modified volumetric model was found to correlate best both the non-catalytic and catalytic gasification reactions. The theoretical models, homogeneous and shrinking-core models, were found to satisfactorily correlate gasification reactions for the non-catalytic and $FeSO_4$-catalyzed reactions. In case of alkali metal catalysts, the catalytic activity was mostly pronounced at a low temperature of $600^{\circ}C$ and observed to decrease by 50% as the temperature was increased to $700^{\circ}C$, and it remained nearly constant at temperature over $800^{\circ}C$. The order of catalytic activity was found to be: $K_2CO_3$ > $Na_2CO_3$ > $K_2SO_4$ > $FeSO_4$.