27. Characteristics of In-Situ Steam Gasification of Nascent Char from Rapid Pyrolysis of Brown Coal

Abstract

In-situ reactivities of nascent chars from the rapid pyrolysis of Victorian brown coals were investigated at temperature and a steam partial pressure of 1173K and 53kPa, respectively, using a drop-tube/fixed-bed reactor. The nascent chars were gasified very quickly in the initial period at rates as high as 0.02s^<-1> on a char carbon basis. The rate of char gasification decreased as the conversion increased and then nearly terminated when the char conversion reached about 90%, leaving refractory material. In-situ gasification was also performed with nascent chars from the pyrolysis with a heating rate of 1K・s^<-1>. Comparing the results with those from the gasification of the rapid pyrolysis chars, it was revealed that the heating rate has no significant positive effect on the reactivity of nascent char with steam.