Pyrolysis and gasification of typical components in wastes with macro-TGA

The pyrolysis and gasification of typical components of solid waste, cellulose, hemicellulose, lignin, pectin, starch, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC) and poly(ethylene terephthalate) (PET) were performed and compared in a macro thermogravimetric analyzer (macro-TGA). Three model biomasses, poplar stem, orange peel and Chinese cabbage, were applied to pyrolysis and gasification simulation by their components based on TG curves. Compared to those from TGA, peaks temperature of the differential thermogravimetric (DTG) curves of each samples pyrolysis on macro-TGA delayed 30-55°C due to heat transferring effect. CO2 promoted the thermal decomposition of hemicellulose, lignin, starch, pectin and model biomasses significantly by Boudouard reaction, and enhanced slightly the decomposition of PET. The activation energy (AE) of biomass components pyrolysis on macro-TGA was 167-197 kJ/mol, while that of plastic samples was 185-235 kJ/mol. The activation energy of 351-377 kJ/mol was corresponding to the Boudouard reaction in CO2 gasification. All overlap ratios in pseudo-components simulation were higher than 0.98 to indicate that pseudo-components model could be applied to both pyrolysis and CO2 gasification, and the mass fractions of components derived from pyrolysis and gasification were slightly different but not brought in obvious difference in simulating curves when they were applied across.