Rapid pyrolysis of coal at high temperature

Rapid pyrolysis of two Chinese coals (Binxian bitumite and Jincheng anthracite) and one Ethiopian lignite were carried out by using a drop tube furnace reactor at 1000℃～1400℃ and atmospheric pressure. The specific surface area and pore structure of the coke from the pyrolysis were measured with carbon dioxide absorption at 273K. It was found that the weight loss of coal increases with the pyrolysis temperature; the weight loss of all the three coals from pyrolysis at high temperature exceeds their respective volatile matter contents from the proximate analysis. However, the three coals of different ranks are also different in the pyrolysis characteristics. The specific surface area of Binxian coal increases after pyrolysis; however, it may decrease when the pyrolysis temperature was higher than the ash melting temperature. SEM characterization indicates that the ash on the surface of Binxian char is in fusion state at high temperature. Furthermore, the correlations between the weight loss and pyrolysis temperature for the three coals was obtained through data regression.