인도네시아 갈탄의 촤-CO2촉매가스화 반응특성연구

Abstract

본 연구는 인도네시아 갈탄인 로토(Roto) 탄의 촤(char)-<TEX>$CO_2$</TEX> 촉매가스화 kinetic 분석을 열중량분석기(thermogravimetric analysis, TGA)를 이용하여 수행하였다. 촉매는 <TEX>$Na_2CO_3$</TEX>, <TEX>$K_2CO_3$</TEX>, <TEX>$CaCO_3$</TEX> 및 천연광물 촉매로 dolomite을 선정하였으며, 석탄과 촉매의 물리적 혼합을 통하여 촤를 제조하였다. 촤-<TEX>$CO_2$</TEX> 촉매가스화반응은 <TEX>$850^{\circ}C$</TEX>에서 <TEX>$CO_2$</TEX> 농도가 60 vol%, 촉매 함량은 <TEX>$Na_2CO_3$</TEX>를 7 wt% 혼합할 때 가장 빠른 탄소전환율을 보여주었다. <TEX>$750{\sim}900^{\circ}C$</TEX> 등온조건에서 촤-<TEX>$CO_2$</TEX> 촉매 가스화 반응결과, 온도가 증가할수록 탄소전환율 속도가 빨라졌으며, 기-고체 반응모델 shrinking core model(SCM), volumetric reaction model(VRM), modified volumetric reaction model(MVRM)을 실험결과에 적용하였을 때, MVRM 이 로토 탄의 가스화반응 거동을 잘 예측하였다. 특히 Arrhenius plot을 통한 활성화에너지는 <TEX>$Na_2CO_3$</TEX>와 <TEX>$K_2CO_3$</TEX>를 혼합한 촤의 활성화에너지가 각각 67.03~77.09 kJ/mol, 53.14~67.99 kJ/mol으로 우수한 촉매 활성을 보여주었다. In this study, We have investigated the kinetics on the char-<TEX>$CO_2$</TEX> gasification reaction. Thermogravimetric analysis (TGA) experiments were carried out for char-<TEX>$CO_2$</TEX> catalytic gasification of an Indonesian Roto lignite. <TEX>$Na_2CO_3$</TEX>, <TEX>$K_2CO_3$</TEX>, <TEX>$CaCO_3$</TEX> and dolomite were selected as catalyst which was physical mixed with coal. The char-<TEX>$CO_2$</TEX> gasification reaction showed rapid an increase of carbon conversion rate at 60 vol% <TEX>$CO_2$</TEX> and 7 wt% <TEX>$Na_2CO_3$</TEX> mixed with coal. At the isothermal conditions range from <TEX>$750^{\circ}C$</TEX> to <TEX>$900^{\circ}C$</TEX>, 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 <TEX>$Na_2CO_3$</TEX> and <TEX>$K_2CO_3$</TEX> were found a 67.03~77.09 kJ/mol and 53.14~67.99 kJ/mol.