AbstractThe major aim of this research was to provide quantitative data about the pyrolytic behaviour of a series of coals from the South Wales Coalfield using thermogravimetry as the major experimental technique. It is hoped that this data will (1) provide information of value to the development of coal conversion technologies, (2) provide information about the kinetics of coal pyrolysis, (3) provide information about the effect upon the kinetic results by the addition of some transition metal elements to two of the coal samples.
An extensive literature survey revealed that work of this nature had not been done previously. It was also revealed that a computer interfaced to the thermogravimetric apparatus to collect and manipulate data would aid the research. An extra aim of the research was added: to interface a Model B BBC Microcomputer to the apparatus and to develop the necessary programs. This aim was successfully realised.
Hot-Stage- Microscopy was used to provide qualitative information about the physical changes the samples underwent during pyrolysis. This information was used to aid the interpretation of the thermogravimetric results.
Thermogravimetric studies of the coals at three heating rates revealed distinct trends in behaviour with rank. The computerised data recording system also revealed more information about the pyrolysis of coals and allowed the tentative suggestion of a system of fingerprinting the pyrolytic behaviour of the coals. One avenue of further research could be the expansion and validation of this system.
The kinetic analysis of the thermogravimetric results revealed that for each sample there are a series of temperature regions with their own activation energy. These regions and activation energies vary with the heating rate. It is suggested that each activation energy relates to a different kind of pyrolysis reaction, and although some suggestions have been made, further research incorporating other techniques is necessary to identify these reactions.
The effect of the addition of some transition metal elements upon the activation energies for two of the samples was then investigated. It was found that most of the metals affected the activation energies in some way - either inhibiting or promoting the reactions. No general trends in behaviour were observed. Another possible avenue of further research is apparent here - to find out the ways in which these metals affect the production of the products of pyrolysis, particularly the gaseous products.
|Date of Award||May 1988|