Pirólise catalítica do PEBD usando como catalisador a vermiculita modificada

Abstract

ResumoO polietileno de baixa densidade (PEBD) é um dos polímeros mais usados atualmente, e a grande quantidade desse polímero produzida resulta em toneladas de resíduos, que necessitam ser tratados. Neste trabalho foi realizada a pirólise termocatalítica do PEBD usando como catalisador a argila vermiculita modificada, como alternativa para o tratamento dos resíduos. A argila foi tratada com solução de ácido nítrico a diferentes concentrações e calcinada a 400 °C. Os materiais foram caracterizados por técnicas de difratometria de raios X, termogravimetria, adsorção de nitrogênio e espectroscopia de energia dispersiva. A pirólise térmica e termocatalítica foi realizada em um micro reator acoplado com GC/MS, a 500 °C. O intuito da pirólise de resíduos poliméricos é a obtenção de hidrocarbonetos leves (C<16), que possam ser empregados na indústria química e petroquímica, através de quebras na cadeia polimérica. Os resultados foram satisfatórios, com aumento no rendimento para hidrocarbonetos leves ao empregar os catalisadores chegando a 71,4% de produtos com C<16, enquanto a pirólise térmica resultou apenas de 25,8%. Palavras-chave: vermiculita, argila, pirólise, PEBD. AbstractLow density polyethylene (LDPE) is one of the most commonly-used polymers currently, and the great quantity of this polymer produced results in tons of waste that must be treated. We studied the thermocatalytic pyrolysis of LDPE with a modified clay vermiculite catalyst as an alternative for treatment of waste. The clay was treated with a solution of nitric acid at different concentrations and calcined at 400 °C. The materials were characterized by X-ray diffraction, thermogravimetry, nitrogen adsorption, and energy dispersive spectroscopy. Thermal and thermocatalytic pyrolysis were carried out in a microreactor coupled with GC/MS at 500 °C. The aim of the polymeric waste pyrolysis is the obtainment of light hydrocarbons (C<16), which can be used in the chemical and petrochemical industry, through breaks in the polymer chain. The results were satisfactory, with an increase in yield for light hydrocarbons by using catalysts reaching up to 71.4% of products with C<16, whereas thermal pyrolysis resulted in only 25.8%.

Estudo da conversão de polietileno de baixa densidade sobre materiais compósitos tipo Nb2O5/HY

“…The second event, in the range of 173 to 327 ºC, begins to reduce the molecular weight related to the elimination of structural hydroxyls from zeolite Y, with about 7 to 11 % reduction in mass. And finally, the third event, with about 80% loss of mass in the temperature range between 292 to 517 ºC, referring to the dominant process of depolymerization of LDPE over catalysts [16]. For all tests using catalysts at different heating rates, at the end of the process, the percentage of mass remaining in the sample crucible was in the range of 14 to 25 %, with a residual average of 19.8 %.…”

“…Valim (2015) [15] characterized the LDPE recycled with Al particulates from long-life packaging for the formation of composites. Bezerra (2016) [16] studied chemically recycled LDPE residues, using modified vermiculite as a catalyst for the final production of light hydrocarbons, which can later be used as raw material for the chemical and petrochemical industry. Coelho et al (2010) [17] made a comparison between the thermal and catalytic degradations of LDPE and HDPE using catalysts based on transition metals (V, Zr and Ni) supported on zeolite Y (NaY and HY).…”