Comparative Studies on K₂CO₃-based Catalytic Gasification of Samhwa Raw Coal and Its Ash-free Coal

Abstract

: Catalytic gasification of raw coals at mild condition is not realized yet mainly due to deactivation of catalysts via their irreversible interaction with mineral matters in coal. In this work, the gasification behavior of ash-free coal (AFC) was compared with that of the parent raw coal. In order to modify the gasification conditions, the raw coal gasified with fixed variables (water supply, space velocity, temperature, catalysts) in a fixed bed reactor. When catalysts are added by physical mixing method with coal, K2CO3 was the most effective additives for steam gasification of coal. However, the activity of ash-free coal (AFC) was much less reactive than raw coal due to high temperature extraction in a 1-methylnaphthalene under 30bar at 370 ℃ for 1 h, almost removed oxygen functional groups, and increased carbonization. The addition of K2CO3 in AFC achieved higher conversion rate at low temperature (700 ℃). At that time, the molar ratio of gases (H2/CO and CO2/CO) was increased because of water-gas shift reaction (WGSR) by addition of catalysts. This shows that catalytic steam gasification of AFCs is achievable for economic improvement of gasification process at mild temperature.

Steam Gasification of Thermally Extracted Ash-Free Coals: Reactivity Effects Due to Parent Raw Coals and Extraction Solvents

“…The conversion at a certain time was calculated as the accumulated amount of product gases divided by the total amount of product gases. , The conversions of Eco, Cyp, Dra, and Hai AFCs extracted using NMP, EDA, 1-MN, and TTL (a total of 16 combinations) are compared in Figure . The Raw conversions are also plotted for comparison.…”

“…Steam gasification of the coals was performed in a fixed-bed reactor. 26 The temperature was increased at a ramp rate of 30 °C/min to 800 °C, where the coals were gasified using steam. The reactor was made of a quartz tube and installed in a vertical furnace.…”