高温下热解温度对煤焦孔隙结构的影响

An experimental study was conducted on the porous structure of the char particles of JX anthracite by using nitrogen absorption method. The coal chars were produced under high temperatures ranging from 1500K to 1800K in a drop tube furnace. The distributions of specific surface area and pore volume with pore diameter were derived by using BET and BJH methods. It is found that the pores in microsize and mesosize are major contributors for the overall specific surface area and pore volume. Furthermore, with the increasing of pyrolysis temperature, the specific area and pore volume vary in the shape of mountain and the temperature of peake is around 1600K. The SEM observation shows that the surface of char particles becomes smoother and denser when the pyrolysis temperature is higher than 1600K. It is suggested that the melting of internal ash during high temperature pyrolysis is the main cause for such a phenomenon, and thus the turning point is related to the melting point of the char.