3.1. Effects of the Reaction Temperature on the Product Yields and Selectivities in Catalytic Co-pyrolysis of Pine Sawdust and PE. The product yields and selectivities as a function of the temperature in catalytic co-pyrolysis of pine sawdust and PE with a spent FCC catalyst are shown in Figure 4 and Table 4. The PE/pine sawdust mass ratio was 1:1. The results show that the aromatic carbon yield is much higher than the olefin yield. The carbon yield of aromatics gradually increased from 22.3% at 400°C to 37.1% at 600°C and then decreased to 24.8% at 650°C, whereas that of C2−C4 olefi
ns increased from 0.4 to 22.4%. The maximum total carbon yield of petrochemicals (aromatic + C2
−
C
4
ole
fi
ns) is 56.7%, which
occurred at 600
°
C. The main aromatic products include
benzene, toluene, ethylbenzene, xylene, styrene, indene,
naphthalene, methylnaphthalene, and multi-methylnaphthalene.
The carbon yields of CO and CH
4
increased gradually with the
increasing temperature, whereas the char and coke yield
decreased signi
fi
cantly.