Evaluación del proceso de co-pirólisis de mezclas de biomasa lignocelulósica y residuos plásticos para la obtención de biocombustible

Abstract

The aim of the current research was to evaluate the co-pyrolysis process of the lignocellulosic biomass with polystyrene (PS) and polypropylene (PP) plastic waste mixture to obtain biofuel and determine its main physicochemical characteristics. The procedure was carried out in a batch reactor with a heating rate of 12 °C-min-1 at a pressure of -0.05 MPa, this was purged with nitrogen and connected to cooling system which provides water at 10 °C to condense the gases. For the copyrolysis tests, it was necessary to work at a temperature of 400 °C (T1) and 450 °C (T2) with 2 mixture compositions; the first composition was called C1 and contained 25% biomass and 75% plastic (50% PS and 50% PP), the second one was called C2 and contained 25% biomass and 75% plastic (75% PS and 25% PP); in this way, solid, liquid (biofuels) and gaseous products were obtained. Fourier Transform Infrared Spectroscopy (FT-IR) as well as Gas Chromatography coupled to Mass Spectrometry (GC-MS) and fuel standards were used to characterize the biofuels obtained. As a result, the maximum yield of biofuels was determined in a 73% at 450 °C with C2 mixture, which mainly contained oxygenated compounds, olefins, naphthenes and nitrogenous compounds due to the elemental composition of the biomass. In addition, its calorific value was 40152 kJ-kg-1. It was concluded that the biofuel with the highest yield was the one which evidenced the presence of PS, which due to its polymeric structure was easier to depolymerize through the heat addition; on the other hand and according to its physicochemical characteristics it could be used as an additive for conventional fuels, so it is recommended not to use biofuel directly in engines.