Tecnologias de conversão térmica para aproveitamento de resíduos polímeros : modelagem e simulação.

Abstract

Polymeric materials have a high percentage in the composition of urban solid waste (MSW). It is estimated that by 2015 around 6300 million tons of polymeric waste were generated, of which 79% was accumulated in landfills or outdoors. All this material could be converted into a high value-added product using thermal conversion technologies. From this perspective, the present research focuses on the development of two models of thermal conversion technologies applied to polymeric materials, pyrolysis and gasification, which allow the evaluation of processes under different operating conditions, as well as the final product obtained. The objective is equally, from a case study based on historical data from the Campina Grande landfill (ASCG), to verify the waste resulting from the simple disposal of polymeric waste and the absence of technologies such as those proposed in this research. In order to fulfill the objectives of the study, the pyrolysis and gasification processes were modeled in Aspen Hysys and Aspen Plus, respectively. Subsequently, based on the modeled processes and data referring to the MSW disposed in the ASCG, a case study of the referred processes applied to the polymeric waste disposed in the ASCG was carried out. Considering the similarity of the results obtained in the modeled processes and experimental data extracted from the literature, it appears that the models are credible and allow the quantitative and qualitative evaluation of the conversion of polymeric materials. Both processes allow the conversion of polymers into high value-added products, however, the main product of pyrolysis, the pyrolysis oil, despite having characteristics that allow its use as an alternative fuel, still needs optimization and research that allow such application, on the other hand, the synthesis gas, a product obtained in the gasification process, allows several chemical routes, which makes it more viable with regard to the application of the final product. A model of an Otto cycle internal combustion engine integrated to the gasification process allowed to observe the net work offered by the synthesis gas, which allows, from 113 kg/hr of polymers, to obtain 72.96 kW. The case study carried out at the ASCG allowed us to observe the large amount of polymer residues accumulated in the ASCG and the waste related to their simple disposal. It is estimated that from August 2015 to August 2021, 123,751.3 tons of polymers were destined for the ASCG, such amount could, from the gasification process, be converted into 211,479.1247 tons of synthesis gas, and from that amount, it would be possible to obtain 10,877.26 tons of hydrogen, 35,299.67 tons of CH4 and 31,473.59 tons of CO, in addition to enabling the production of 109,450.7 KW. It is estimated that the implementation of the gasification process at the ASCG would make it possible to obtain, from 2023 to 2026, 178,905.5 tons of synthesis gas and generate 92,592.3 KW. In general terms, it can be concluded that the thermal conversion technology models proposed in the present research offer an alternative for the analysis of pyrolysis and gasification processes applied to the conversion of polymeric materials and that the gasification process can be proposed as a viable alternative within of the urban solid waste management plan of the ASCG and of large urban centers with a similar situation.