**5.3 Solid products**

168 Material Recycling – Trends and Perspectives

Fig. 13. Liquid products distribution obtained from the catalytic cracking of low-density

Fig. 14. Liquid products distribution obtained from the catalytic cracking of low-density polyethylene employing heteropolyacid-MCM-41 materials (Hernandez et al., 2010).

While Al-MCM-41 and Ga-MCM-41 produced a relatively large gasoline yield (Figure 13), the HPA-MCM-41 catalyst at the same reaction conditions, produced a large proportion of heavier hydrocarbon fractions, as gas oil, followed by fuel oil and then, gasoline and kerosene (Figure 14). We consider that even if the HPA70 has a large number of initial

polyethylene employing different porous solid catalysts (Ortega et al., 2006).

When we have carried out the polyethylene catalytic decomposition, a small proportion of solid products have been obtained, in the form of waxes. For comparison, we run the same polymer decomposition at the same reactor conditions without any catalyst, being in fact, the pyrolysis of the polymer. The pyrolysis test yield a large proportion of solid products, 90.67% w/w (Ortega et al., 2006).

For the particular case of the catalytic cracking of poly(ethylene therepthalate), we have obtained a large proportion of solid therepthalic acid.
