ZnO NANOPARTICLE DEPENDENT NON-ISOTHERMAL PYROLYSIS OF ASSAM COAL (INDIA) PART I: KINETIC STUDY

Abstract

To promote the use of abundant low rank Assam coal resources, it is necessary to understand the extent of emission of volatile species from the coals on thermal treatment. As no pyrolysis work seems to be done with most of the coals so far using a green catalyst, ZnO nanoparticles, this study is an attempt to visualize the magnitude of volatile species released from the thermal treatment of Assam coal in nitrogen atmosphere which is a great environmental concern. The evolution of volatile species for the 72 BS sized unblended coal, have been found to be higher than those samples containing varying amounts of ZnO. For 100BS sized coal particles, similar amounts of volatiles from the unblended coal as well as blended coal of (coal : ZnO for100:5 and 100:7.5) have been observed but for 100:10 ratio ZnO blended samples decrease of volaties has been found. Kinetic study reveals that the rate of reaction was initially very fast and then gradually declined. Moreover, the rate constants for the blended samples have been observed to be lower than that of the unblended samples. The presence of ZnO nanoparticles increases the thermal stability of the coal particles. The present work is a new approach of using ZnO nanoparticles for low emission of volatiles from thermal treatment of coal and understanding the kinetics of pyrolysis process and therefore, has to some extent environmental and technological interests.