Determinación de la cantidad de compuestos aromáticos, nafténicos y parafínicos de la fracción líquida obtenida de la pirólisis térmica de poliestireno

Abstract

The excessive use of polystyrene-based plastics has generated a high waste of this material. This problem, accompanied by the growing demand for fuels, has created the need to take advantage of these wastes by thermal pyrolysis and to obtain fuels that require to be analyzed in their chemical composition and properties in order to determine their usefulness; therefore, the objective of this research was to determine the amount of aromatic, naphthenic and paraffinic compounds present in the liquid fraction obtained from the thermal pyrolysis of compact polystyrene. The methodology implemented had a quantitative approach with an experimental type investigation, where the manipulated variable was the amount of compact polystyrene fed into a Batch type reactor under conditions of residence time of 261 minutes, pressure of -0.05 kPa and temperature of 425 °C. The resulting liquid fraction was subjected to analysis according to ASTM standards to determine its physicochemical properties, complementing the study with the determination of its critical thermodynamic properties and the analysis of the chemical composition by gas chromatography coupled to mass spectrometry and with the Wuithier method. The results indicated a closeness to the physicochemical properties of diesel fuels with a composition represented by a majority concentration of aromatic carbons of 66.52% and the presence of 17 different compounds, followed by naphthenic carbons which are present in 24.19% and paraffinic carbons with 9.29%. In conclusion, the polystyrene pyrolysis liquid fraction proved to be a mixture of hydrocarbons with properties not suggested for use as fuel directly, however, its aromatic character indicated its usefulness as a raw material or additive in obtaining petroleum products such as high octane gasoline and organic solvents.