The most dramatic change made by the addition of PP was the reduced H2O content in bio-oil. As shown in Table 3, the H2O content in the bio-oil obtained from co-pyrolysis was 4.63 wt% (non-catalytic) and 8.93 wt% (catalytic), while that in the bio-oil from the pyrolysis of L. japonica only was 42.03 wt% (non-catalytic) and 50.32 wt% (catalytic). The addition of PP enhanced the see more supply of C and H, resulting in the substantially decreased H2O content in bio-oil. Catalytic co-pyrolysis produced more CO, CO2, and C1-C4 hydrocarbons, compared to non-catalytic co-pyrolysis, indicating that deoxygenation reactions were promoted by catalyst.
The increase in the water content (from 4.63 to 8.93 wt%) by catalytic reforming suggests the enhancement of dehydration by catalyst. Figure 6 Product yields of catalytic co-pyrolysis of Laminaria japonica and polypropylene. Table 3 Yield of gas composition from catalytic co-pyrolysis of Laminaria japonica and polypropylene Catalyst
Without catalyst Al-SBA-15 Yield (wt%) CO 1.63 2.10 CO2 12.61 13.88 C1 ~ C4 5.37 6.46 Water contents in bio-oil (wt%) 4.63 8.93 Figure 7 shows the species distribution of the bio-oil obtained from the catalytic co-pyrolysis using Py-GC/MS. Compared to the this website result of the catalytic pyrolysis of L. japonica only (Figure 3), the addition of PP increased the content of hydrocarbons Proteasome purification enormously, making it the most abundant species in the bio-oil, because the main product species of the cracking of polypropylene are hydrocarbons. Catalytic co-pyrolysis reduced the content of oxygenates considerably compared to non-catalytic co-pyrolysis. This was attributed to the conversion of oxygenates into mono-aromatics or PAHs on the acid sites of Al-SBA-15. Figure 7 Product distribution of bio-oil from catalytic co-pyrolysis of Laminaria japonica and polypropylene. Total hydrocarbon content was reduced a little by catalytic reforming. According to the carbon number distribution of hydrocarbons shown in Figure 8, non-catalytic co-pyrolysis produced mainly large-molecular-mass hydrocarbons (≥C17). These wax species must be decomposed using adequate catalysts because they cause process blockage
and deteriorate not the oil quality. In this study, most large-molecular-mass hydrocarbons were removed by Al-SBA-15. They are believed to have been cracked into gasoline-range hydrocarbons (C5-C9) and diesel-range hydrocarbons (C10-C17) on the acid sites of Al-SBA-15. A previous study on the catalytic pyrolysis of PP over Al-SBA-15 reported that Al-SBA-15 decomposed PP into C5-C17 hydrocarbons . Figure 8 Carbon number distribution of hydrocarbons from catalytic co-pyrolysis of Laminaria japonica and polypropylene. Conclusions The catalytic co-pyrolysis of L. japonica and polypropylene resulted in the production of bio-oil with significantly higher quality compared to the catalytic pyrolysis of L. japonica only or the non-catalytic co-pyrolysis.