Impact of gas concentrations on the self-activation of southern yellow pine during the pyrolysis process.

Self-activation is an endothermic process in the form of physical/thermal activation that utilizes the gases produced during the high temperature pyrolysis of a carbonaceous material. This serves as the activation agent resulting in the conversion of the material into activated carbon. Because the pyrolysis happens in a sealed high temperature environment, it is currently difficult to monitor and understand the interactions between the gasses present and the state of the carbons present. The objective of this study was to develop a real-time gas monitoring system to monitor gas changes during the self-activation process in the pyrolysis of biomass. Southern yellow pine was subjected to self-activation where an external gas sensor array was used to observe the real-time changes in the CO₂ and H₂; the gas concentrations were measured at intervals throughout the dwelling time from the sealed environment to observe the changes that occurred. Gas chromatography and surface area characterization were performed in order to compare what happened within the furnace to the resulting products of the self-activation and the gas concentration readings. The effectiveness of the gas sensor array was corroborated by showing that the peak CO₂ around sample run 6 coincided with peak CO₂ reading in the gas chromatography which declined as processing continued. Peak X-ray diffraction (XRD) value and a sharp peak in the Fourier-transform infrared spectroscopy (FTIR) due to degradation of cellulose and hemicellulose were contributed to the carbonization of the southern yellow pine. These findings can be correlated to the changes in gasses throughout pyrolysis processing showing the effectiveness of the gas sensor array used to monitor the process. [ABSTRACT FROM AUTHOR]