Pyrolysis is a thermochemical step used to clean coal from sulfur and tar contents before being gasified into syngas. In this work, the effect of pyrolysis temperatures (550 and 900 oC) on the structure properties of generated chars, using both microwave and conventional methods, were investigated. Results showed that microwave pyrolysis of coal produced more gases but less tars compared to conventional pyrolysis. Self-gasification between coal carbon and generated CO2, formed during microwave pyrolysis, could explain the high CO/CO2 ratio (&gt;1) observed under microwave compared to that under conventional pyrolysis (CO/CO2 &lt;1). Additionally, in microwave pyrolysis, the generated oil tars exhibited lower concentrations of polar oxygenates, as observed from the GC-MS results. Similarly, the wax tars showed higher concentrations of nonpolar alkanes, as observed from the intensity of C-H vibrations in FTIR. Both the GC-MS and FTIR analysis of the generated tars (oils and waxes) could suggest that the microwave interact preferentially with these polar volatiles which have relatively higher dielectric property compared to alkanes. The structure-reactivity of generated chars was also investigated using a variety of characterization tools such as XRD, BET, SEM, EDS, and FTIR. Finally, the char reactivity towards combustion will also be discussed.

Structure reactivity of generated chars during microwave and conventional pyrolysis

254th National Meeting (2017)

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