STUDY OF ACTIVATION OF COAL CHAR

This is the second report on a project whose aim is to explore in a fundamental manner the factors that influence the development of porosity in coal chars during the process of activation. It is known that choices of starting coal, activating agent and conditions can strongly influence the nature of an activated carbon produced from a coal. This work has again confirmed that there is a fundamental difference in char structure that is reflective of the source of the chars. What is new in the present results is a strong indication that this difference is seen, irrespective of the conditions of char preparation. Results were compared for utility combustion chars, all of which were prepared under the very high intense heating conditions of utility boilers, and the laboratory-prepared chars prepared at orders of magnitude lower heating rates. The chars were of very similar nature regardless of the heating conditions that led to their preparation (and despite major differences in level of burnoff). On the other hand, the results from the examination of the laboratory char results do again suggest that the activation conditions play some role in determining porosity, though their effect is decidedly less important than the role of the parent material. This is true despite an enormous range of reactivity exhibited by the activating agents