Pirólise térmica e catalítica de policloreto de vinila pós consumo utilizando catalisadores micro/mesoporosos do tipo ZSM-35/MCM41

• Ano de defesa: 2019
• Autor(a) principal: Silva, Thereza Helena Azevedo
• Orientador(a): Souza, Marcelo José Barros de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Programa de Pós-Graduação: Pós-Graduação em Engenharia Química
• Palavras-chave em Português: Engenharia química; Pirólise; PVC (cloreto de polivinila); Catalisadores; PVC; Catalisadores micro/mesoporosos
• Palavras-chave em Inglês: Pyrolsis; Micro/mesoporous catalysts
• Área do conhecimento CNPq: ENGENHARIAS::ENGENHARIA QUIMICA
• Link de acesso: https://ri.ufs.br/jspui/handle/riufs/17799

Polyvinyl chloride (PVC), has been widely used for various purposes due to its low price and good durability, this being one of the most important and comercialized materials currently. However, incorrect its disposal contributes to high waste generation. In the perspective of energy recovery and reciclyng, the pyrolysis of PVC waste has proved to be one of the most promising methods of recycling and energy recovery. The present work studied a thermal pyrolysis of post-consumer PVC as well as its catalytic pyrolysis using micro/mesoporous catalysts type ZSM-35/MCM-41. The MCM-41 was synthesized by the hydrothermal method, the HZSM-35 acid zeolite was obtained by ion exchange and the micro/mesoporous catalysts ZSM-35/MCM-41 were developed by the mechanical method in the following mass proportions: 25/75, 50/50 and 75/25. The samples were characterized by X-ray diffraction (XRD), adsorption/desorption of N2 at 77 K. The pyrolysis tests were performed in a thermobalance in the temperature range of 30 to 900 °C and using heating rates of 5, 10 and 20 °C min-1 . The ZSM-35/MCM-41 X-ray diffractograms showed the characteristic peaks of MCM-41 and ZSM-35 zeolite with good crystallinity. The adsorption of N2 at 77 K showed that the MCM-41 presents type IV isotherm and the ZSM-35 zeolite presents type I isotherm and the ZSM-35/MCM-41 materials presented isotherms with type I and IV characteristics. The total area of the ZSM-35/MCM-41 catalysts decreased as the MCM-41 ratio decreased in the catalyst. The thermal pyrolysis results showed that PVC decomposes into two main events, between 200 and 400 °C, and between 400 and 600 °C. The catalytic decomposition of PVC occurred in two stages, and the parameters heating rate and catalyst composition influence the pyrolysis process. Under the studied conditions, the ZSM-35/MCM-41 catalysts promoted a decrease in the average temperatures of the PVC decomposition events and showed satisfactory conversion values.