Produção de estireno via pirólise de resíduos de poliestireno a partir do tratamento químico com hidróxido de sódio

Abstract

With the increase in the use of plastic materials, especially disposable ones based on polystyrene, there has been an increase in the production of waste all over the planet, which ends up causing several socio-environmental problems. Several methodologies have emerged as means of recycling, such as pyrolysis, in order to provide a technological route for plastic waste. In this context, the project in question aimed to study the impregnation with Sodium Hydroxide as a catalyst for optimizing the pyrolysis process of an Equimolar Blend of disposable cups (PSAI) and food packaging (XPS) waste. The experiments were carried out in triplicates with Sample without impregnation and with impregnation to compare the efficiency of the converter, in batch mode, with a stainless steel reactor with a volume of 260 mL, at a temperature of 500 ºC at 1.0 atm, inserted in a cylindrical oven with digital temperature control at a rate of 10 ºC/min and a cooling system formed by a straight condenser. The products obtained in the process outside the non condensable gases, the liquid product obtained (PLO) and the solid phase (coal). The liquid fractions were located by density, velocity, refractive index and GC-FID chromatography. The PLO's obtained, presented their average yields of 66.47% (without impregnation), 74.73% (with impregnation - washed) and 54.17% (with impregnation). As for the physical-chemical characteristics, the average values obtained for the products without impregnation were 0.9724𝑔/𝑐𝑚3of density, 1.3459 𝑚𝑚2/𝑠 of and 1.5483 for the index of refraction, for the chemical impregnations with washed samples we have 0.9585 𝑔/𝑐𝑚3 of density, 1.0457 𝑚𝑚2/𝑠 of degree and 1.5472 for the index of refraction and for the Sample with chemical impregnations has 0.9712 � �/𝑐𝑚3 of density, 1.2709 𝑚𝑚2/𝑠 of advances and 1.5479 for the index of refraction. The results of the CG-FID indicated the following quantification of styrene contents for the sample without impregnation of 54.87%, with impregnation in the washed samples of 63.52% and without washing of the samples was 59.53%. The data obtained experimentally showed that NaOH, associated with a washing step after impregnation, is an efficient catalyst for the pyrolysis process, increasing the purity of the liquid product obtained and the process yield, reaching the energy expenditure of the process, being a viable method for recycling this material and reusing these products for the production of polystyrene.