:We investigated the effects of the concentration of carbon dioxide on the char-CO2 gasification reaction under isothermal conditions of 850 ℃ using the Drayton coal. Potassium carbonate was used to improve the low-temperature gasification reactivity. The enhancement of carbon dioxide concentration increased the gasification rate of char, while gasification rate reached a saturated value at the concentration of 70%. The best CO2 concentration for gasification is determined to be 70%. We compared the shrinking core model (SCM), volumetric reaction model (VRM) and modified volumetric reaction model (MVRM) of 306

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Nanosized Pt-Sn/VC and Pt-Co/VC electrocatalysts were prepared by a one-step radiation-induced reduction (30 kGy) process using distilled water as the solvent and Vulcan XC72 as the supporting material. While the Pt-Co/VC electrodes were compared with Pt/VC (40 wt%, HiSpec 4000), in terms of their electrocatalytic activity towards the oxidation of H2, the Pt-Co/VC electrodes were evaluated in terms of their activity towards the hydrogen oxidation reaction (HOR) and compared with Pt/VC (40 wt%, HiSpec 4000), Pt-Co/VC, and Pt-Sn/VC in a single cell. Additionally, the prepared electrocatalyst samples (Pt-Co/VC and Pt-Sn/VC) were characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical surface area (ECSA), and fuel cell polarization performance.

:We have investigated the effects of various additives on Eco coal gasification under CO2 atmosphere. The temperature ranges from 750~900 ℃ and the gasification experimental was carried out with Eco coal adding 7 wt% K2CO3, Na2CO3, CaCO3, Dolomite, and non-additive under N2 and CO2 gas mixture. At 850 ℃, we observed that the reaction rate increased when the concentration of CO2 increased. However, we also observed that the increment of reaction rate was small at more than 70% of the concentration of CO2. The additives activity was ranked as 7 wt% Na2CO3 > 7 wt% K2CO3 > non-additive > 7 wt% Dolomite > 7 wt% CaCO3 at 850 ℃. At the temperatures of 750 ℃, 800 ℃, 850 ℃, and 900 ℃, when the temperature increased, the gasification rate increased. The gasification was suitably described by the volumetric reaction model. Using volumetric reaction model, the activation energy of Eco coal including 7 wt% Na2CO3 gasification was 83 kJ/mol, which was the lowest value among all the alkaline additives.

요 약본 연구는 인도네시아 갈탄인 로토(Roto) 탄의 촤(char)-CO 2 촉매가스화 kinetic 분석을 열중량분석기(thermogravimetric analysis, TGA)를 이용하여 수행하였다. 촉매는 Na 2 CO 3 , K 2 CO 3 , CaCO 3 및 천연광물 촉매로 dolomite을 선정하였으며, 석탄과 촉매의 물리적 혼합을 통하여 촤를 제조하였다. 촤-CO 2 촉매가스화반응은 850 o C에서 CO 2 농도가 60 vol%, 촉 매 함량은 Na 2 CO 3 를 7 wt% 혼합할 때 가장 빠른 탄소전환율을 보여주었다. Abstract − In this study, We have investigated the kinetics on the char-CO 2 gasification reaction. Thermogravimetric analysis (TGA) experiments were carried out for char-CO 2 catalytic gasification of an Indonesian Roto lignite. Na 2 CO 3 , K 2 CO 3 , CaCO 3 and dolomite were selected as catalyst which was physical mixed with coal. The char-CO 2 gasification reaction showed rapid an increase of carbon conversion rate at 60 vol% CO 2 and 7 wt% Na 2 CO 3 mixed with coal. At the isothermal conditions range from 750 o C to 900 o C, the carbon conversion rates increased as the temperature increased. Three kinetic models for gas-solid reaction including the shrinking core model (SCM), volumetric reaction model (VRM) and modified volumetric reaction model (MVRM) were applied to the experimental data against the measured kinetic data. The gasification kinetics were suitably described by the MVRM model for the Roto lignite. The activation energies for each char mixed with Na 2 CO 3 and K 2 CO 3 were found a 67.03~77.09 kJ/mol and 53.14~67.99 kJ/mol.