engleski

Synergetic effect of waste plastics and straw co-pyrolysis: a combined study in thermogravimetric analyser and a fixed bed reactor

In 2016, the global plastics production reaches 500 million tons, half of which are treated by landfill, inducing severe environmental pollution. Upgrading of plastic waste through pyrolysis has been regarded as one of the most environmental and sustainable treatment methods. In recent years, co-pyrolysis of plastic waste with biomass waste has received much more attention because it provides a more alternative and flexible way to dispose and convert these two kinds of solid wastes into valuable products like biogas, tar and biochar, etc. In this study, the co-pyrolysis of plastic waste and biomass (wheat straw) is experimentally studied in a non-isothermal thermogravimetric analyser (TGA, STA-409PC, NETZSCH, German) and a fixed-bed reactor. TGA test is operated from room temperature to 1000°C, while the fast pyrolysis in fixed-bed reactor is tested in the temperature range of 800-1100°C. The product compositions of gas and tar are analysed by gas chromatography (GC- 2014, Shimadzu, Japan) and mass spectrometry (GC-MS-QP2020, Shimadzu, Japan), respectively. The synergetic effects in co-pyrolysis cases are obtained through the comparison between the measured values and the mass averaged values. A synergetic effect during the plastics and biomass co-pyrolysis is detected by TGA, that the experimentally measured TG-DTG curves are lagged and maximum mass loss rates are reduced, compared with the theoretical ones. Because of the higher carbon and volatile contents and the lower oxygen content in plastics than biomass, the plastics pyrolysis produces a higher yield of soot (11.1-17.4 wt.% at 1000-1100 oC), as well as a higher yield of tar and a higher H2 content in gas phase ; while the gas and char yields and the CO and CO2 contents in gas phase during the plastics pyrolysis are lower than the biomass pyrolysis. The synergetic effect degree during the plastics and biomass co- pyrolysis depends on the temperature and mixing ratio. Overall, the maximum synergetic effect degree is under the mixing conditions with 25- 50 wt.% biomass.

Plastics ; Biomass ; Co-pyrolysis ; Synergetic effect ; Thermogravimetric analysis

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