화학공학소재연구정보센터
Energy & Fuels, Vol.28, No.8, 5241-5251, 2014
Adsorption Behavior of CO2 in Coal and Coal Char
Recent interest in sequestration of carbon dioxide (CO2) in gasified coal seam (i.e., post-underground coal gasification sites) has created a need to understand the coal properties, specifically, the adsorption behavior of CO2 on gasified coal. In the present study, the CO2 excess adsorption isotherms were determined for four coal samples of different characteristics based on the volumetric method. Further, coal chars from a coking coal and a non-coking coal (within the studied samples) were investigated for their CO2 adsorption capacity. The coal samples of size 22-32 mm were pyrolyzed in a drop-tube furnace at 800 and 1000 degrees C with a heating rate of approximately 2.5 degrees C s(-1) under an inert atmosphere. Measurements were performed up to a pressure of 65 bar for all of the studied samples. Experiments were carried out at an isothermal temperature of 45.5 degrees C. The influence of coal properties on adsorption was also studied and compared to the literature data. Behavior of adsorption capacities was analyzed as a function of coal properties, such as vitrinite content, coal rank, volatile matter, ash content, and surface area. Results indicated that the adsorption capacity of coal char is much higher in comparison to the virgin coal samples. It was understood from the surface area analysis that there is a significant increase in surface area when coal is pyrolyzed. In addition, for coal samples, the trend of adsorption isotherms was in good agreement with the literature data.