Degradação termocatalítica de misturas de poliolefinas e biomassa

Abstract

The pyrolysis of waste plastics, particularly polyolefins, arouses great interest for the valorization of these waste, as it allows high yields of fuels and raw materials to be obtained for the benefit of the petrochemical industry.Pyrolysis of waste polypropylene (PP) and waste high density polyethylene (HDPE) were carried out in a fixed bed reactor in order to evaluate the influence of pyrolysis temperature (450 to 500 °C) and flow of sweeping gas (N2) (50, 80 and 100 mL min-1 ) on the yields of collected product, residueand gas. The highestyield in collected product was obtained attemperature of 450 °C and 50 mL min-1 forPP and 500 °C and 80 mL min-1 for HDPE. At this condition, thermal cracking experiments were carried out with polyolefins and dried leaves of Terminalia catappamixturesin 2/1, 1/1 and 1/2ratios, being that the highest yield ofcollected product was obtained at the 2/1 ratio. The main cheminal groups formed were acid, furan and amine groups. Thepyrolysis of polyolefins carried out with the catalysts SO4/SnO2_3x and H-ZSM-5 at 3/1, 2/1 and 1/1 ratios,evaluated the effects of each catalyst on the collected products yields. The SO4/SnO2_3x catalyst generated high liquid productsyields, while the zeolite producedhigh gas yield. The use of zeolite for pyrolysis of polyolefins and biomass mixtures at 3/1, 2/1 and 1/1 ratios of mixture/catalyst increased the formation of aromatics and decreased the final paraffincontent of products, also promoting efficient removal of oxygen.