Catalytic pyrolysis of waste plastic from electrical and electronic equipment

Abstract

Plastic waste collected from waste electrical and electronic equipment (WEEE) was pyrolysed in the presence of zeolite catalysts to produce a gasoline range aromatic oil. The plastic was from equipment containing cathode ray tubes (CRTs) and also plastic waste from refrigeration equipment. In addition, for comparison the main plastics contained in the WEEE, in the form of high impact polystyrene (HIPS) and acrylonitrile-butadiene-styrene (ABS) were also pyrolysed in the presence of the zeolite catalysts. Two zeolite catalysts; Y zeolite and ZSM-5 were used. Catalytic pyrolysis took place in a two stage fixed bed, batch reactor with the plastic pyrolysed in the first stage and the evolved pyrolysis gases catalysed in the second stage reactor. The quantity of oil produced from uncatalysed pyrolysis of plastics from CRTs and refridgerators was more than 80 wt%. The gases consisted of hydrogen, methane and C 2 -C 4 hydrocarbons. When the zeolite catalysts were introduced there was a decrease of between 5-10 wt% in oil yield and a corresponding increase in gas yield.The composition of the oils derived from the uncatalysed pyrolysis of WEEE plastics were mainly aromatic with high concentrations of styrene, derived from the HIPS and ABS present in the plastic waste. Addition of the zeolite ZSM-5 and Y zeolite to the pyrolysis process resulted in significant concentrations of benzene, toluene and ethylbenzene in the product oil but reduced concentrations of styrene. The oils from both thermal and catalysed pyrolysis also contained significant concentrations of polycyclic aromatic hydrocarbons for example, naphthalene, phenanthrene and pyrene.

Characterization of Some Real Mixed Plastics from WEEE: A Focus on Chlorine and Bromine Determination by Different Analytical Methods

“…Despite the heterogeneity of the investigated WEEE, it can be observed that the values reported in this work fall within the range of those reported by various authors. It must be emphasized that in most studies reported in the literature which deal with processes development rather than analytical methods, XRF used for screening or semi-quantitative analysis [9], and IC [35,[39][40][41] are the most used techniques.…”

A review on thermal and catalytic pyrolysis of plastic solid waste (PSW)

“…Aguado et al (2007) also conducted a thermal gravimetric analysis (TGA) to evaluate the activity of catalysts by determining the degradation temperature shifts. Without the presence of catalyst, the LDPE started degradation at 419 o C. Employing n-HZSM-5 catalyst, reduced the degradation temperature to 396 o C. Muhammad et al (2015) pyrolysed WEEE in the presence of ZSM-5 and Y-zeolite catalysts using a fixed bed two-stage batch reactor with the plastic pyrolysed in the first stage and the evolved pyrolysis gases catalysed in the second stage reactor for further upgrading and cracking. The main plastics contained in the WEEE were high impact polystyrene (HIPS) and acrylic butadiene styrene (ABS) and were treated in the presence of the zeolite catalysts.…”

Recycling and Mechanical Characterization of Polymer Blends Present in Printers

“…Electronic waste represents around 8% of the urban waste volume worldwide 2 . In Europe about 10 million tons WEEE are produced each year 3 and it is estimated that by 2020 the amount generated will reach a total annual tonnage of 12.3 million 4 . Since many times fixing devices is not economically feasible, old electronics are discarded in large quantities.…”