Experimental Investigation on Air Gasification of Polypropylene Particles in a Microwave Fluidized Bed Reactor

The processing of polypropylene (PP) waste has become a technological issue that has attracted the attention of researchers. The effects of the gasification temperature, equivalence ratio (ER), and microwave power on syngas yields of PP air gasification were studied. When the gasification temperature rose from 700 to 900 degrees C, the syngas increased from 56.3 to 85.6 wt %, while the liquid oil and wax decreased. With an increase in ER from 0.05 to 0.25, there was a corresponding increase in syngas yield from 78.2 to 87.2 wt %, whereas the oil yield decreased from 10.0 to 3.2 wt %, and the wax increased from 11.8 to 13.9 wt % and then decreased to 9.6 wt %. When the microwave power rose from 600 to 1000 W, the syngas yield increased from 78.2 to 84.0 wt % first and then decreased to 68.9 wt %, whereas the oil yield decreased from 10.3 to 3.1 wt %, and the wax increased from 11.7 to 28.1 wt %. The optimal syngas yield of 87.2 wt % was obtained when the pyrolysis temperature was 900 degrees C, ER was 0.15, and microwave power was 800 W. The higher heating value of the syngas produced was 19.3 MJ/Nm3, while the gasification of PP achieved a maximum cold gas efficiency of 79.1%.