Use of an innovative TGA apparatus for sampling the emissions generated by pyrolysis of plant assisted bio-remediation biomass

Plant-assisted bioremediation (PABR) represents a green technique for the recovery and remediation of contaminated areas. The biomass produced by these crops is generally considered as a contaminated waste product and potentially harmful. Therefore, it is very important to characterize these biomasses aiming at understanding if they can be treated like traditional biomasses and it is possible to use them in energy conversion process (pyrolysis, gasification, etc.). In this work, the energy conversion processes is simulated through an innovative TGA-DTA analysis using PABR poplar pruning and the emissions are characterized to assess the distribution of the contaminants in the effluent. The TGA-DTA system is interfaced with a particulate filter and a bubbling system for capturing metals. To assess the potential of easily repeatable, small scale TGA-DTA analysis in predicting the main aspects of the gasification process, the results of the experiment are compared with those obtained using the same biomass in a lab-scale fluidized bed gasification (FBG) plant. This comparison showed a good agreement between laboratory tests and those conducted on the real system, confirming that the proposed instrumental apparatus represents an interesting predictive tool for determining the fate of the metals contained in biomass. The analysis also showed that Cd is completely concentrated in the bottom ashes, while as for the other metals, such as Mn, Fe, Cu, Zn, not negligible concentrations are found in the fugitive ashes, e.g. bubbling gases, and then specific metal trapping must be considered in case of PABR gasification.