# Characterization and Use of Char Produced from Pyrolysis of Post-Consumer Mixed Plastic Waste
## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Temperature**, \({}^{\circ}\)C & \multicolumn{3}{c}{**Yield (\%)**} \\ \cline{3-5}  & & **Solid** & **Liquid** & **Gas** \\ \hline \multirow{4}{*}{PP} & 450 \({}^{\circ}\)C & 3.97 & 31.67 & 64.36 \\ \cline{2-5}  & 500 \({}^{\circ}\)C & 0.69 & 47.63 & 51.69 \\ \cline{2-5}  & 550 \({}^{\circ}\)C & 1.29 & 49.18 & 49.54 \\ \hline \multirow{4}{*}{PS-HIPS} & 450 \({}^{\circ}\)C & 10.61 & 27.17 & 62.22 \\ \cline{2-5}  & 500 \({}^{\circ}\)C & 9.02 & 31.69 & 59.29 \\ \cline{2-5}  & 550 \({}^{\circ}\)C & 3.53 & 42.31 & 54.16 \\ \hline \multirow{4}{*}{PS-ESP} & 450 \({}^{\circ}\)C & 1.55 & 52.35 & 46.10 \\ \cline{2-5}  & 500 \({}^{\circ}\)C & 1.46 & 57.37 & 41.17 \\ \cline{2-5}  & 550 \({}^{\circ}\)C & 1.00 & 58.09 & 40.91 \\ \hline \multirow{4}{*}{Film} & 450 \({}^{\circ}\)C & 13.40 & 25.06 & 61.54 \\ \cline{2-5}  & 500 \({}^{\circ}\)C & 6.26 & 52.63 & 41.11 \\ \cline{2-5}  & 550 \({}^{\circ}\)C & 4.39 & 42.94 & 52.67 \\ \hline \multirow{4}{*}{Plastic waste mixture} & 450 \({}^{\circ}\)C & 4.56 & 27.53 & 67.91 \\ \cline{2-5}  & 500 \({}^{\circ}\)C & 3.19 & 42.82 & 53.99 \\ \cline{1-1} \cline{2-5}  & 550 \({}^{\circ}\)C & 2.38 & 44.25 & 53.37 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Yields to products obtained in the pyrolysis tests with the different plastic materials. and pine biomass, at different temperatures (between 350 and 450 \({}^{\circ}\)C) observing that an increase in temperature decreases the yield of the liquid product in favor of the gaseous product, due to the fact that at higher temperatures the cracking reactions of the material are favored, transforming the long-chain and heavy molecules into shorter and lighter molecules. Therefore, the authors established a temperature of 400 \({}^{\circ}\)C as the most optimal to maximize the production of liquid. The yield of the solid product was not greatly affected by the temperature, remaining at around 15% in all the tests. [PERSON] et al. [4] in their study about pyrolysis of mixtures of high-density polyethylene, low-density polyethylene, polypropylene and polyvinyl chloride reported that the predominant product is liquid with yields between 53.7% and 36.8%. The yield of the solid was not higher than 10%, being 4.9% in the case of thermal pyrolysis in the absence of catalyst. It is worth noting the research of [PERSON] et al. [7; 46] on the pyrolysis of HDPE, LDPE and PP plastic waste separately. These researchers reported that an increase in temperature favors the degradation of the plastic material so that more gaseous compounds are produced. This was more reflected in the case of HDPE because it has shorter chains than LDPE and is easier to break down and form gaseous compounds. The yield of the solid product was also affected by temperature in the same way as the liquid, so the highest yield was 2.34% (HDPE) and 10.12% (LDPE) at 300 \({}^{\circ}\)C and 2.14% (HDPE) and 6.14% (LDPE) at 700 \({}^{\circ}\)C. For pyrolysis of PP under the same conditions, comparing the results with those obtained in the present work, a notable difference was observed in terms of yield values, especially in the liquid (79.62-75.05%) and solid (17.71-22.78%) products. In addition, these yields followed an inverse trend, as the research by [PERSON] et al. [46] showed a decrease in the yield of the liquid product in favor of the gaseous product as the temperature increases. For the solid product, the same decreasing trend with temperature was observed, with similar values (2.67-2.17%).