5-7 OCTOBERISFR2011

55

TOLEDO (SPAIN)PRODUCTION OF FUEL BY LOW TEMPERATURE PYROLYSIS FROM WASTE
ELECTRICAL AND ELECTRONIC EQUIPMENT PLASTICS
A. Asueta, I. Robertson, M. Arieta-Araunabeña, D. Iribarnegaray, I. Acillona, S. Arnaiz
GAIKER Technology Centre, Parque Tecnológico, Edificio 202, 48170 Zamudio, Spaine-mail: asueta@gaiker.esAbstract
The huge increase in the generation of post-consumer plastic wastes has produced a growing interest about eco-efficient
strategies and technologies for their appropriate management and recycling. In response to this, PROQUIPOL Project isworking on developing, optimizing and adapting feedstock recycling technologies as an alternative of management for thetreatment of complex plastic wastes. Among the different plastic wastes studied, the aim of PROQUIPOL Project is toprovide a suitable treatment to a plastic fraction from commercial waste electrical and electronic equipment (WEEE)
authorized treatment facility by pyrolysis. The collected residue is formed by a complex plastic mixture (ABS, PS, PP…) withthe presence of metals. Initially, the composition of selected residues was determined using different analytical techniques.
Pyrolysis test have been carried out using reference samples and the selected waste stream to study the distribution ofliquid, solid and gas products. Pyrolysis liquids were analyzed with GC/MS and High Heating Value (HHV) test. Reasonably
results, in terms of yield and composition of the liquid fraction, were obtained. The obtained pyrolysis liquids have a potential
use fuel-like applications or as chemical source, the metal content may be recycled and the gas fraction can be use to cover
the energy demand of the process.

Keywords: pyrolysis, WEEE plastics, polyolefins, styrenics, feedstock recycling

1. Introduction
The large increase in the generation of plastic wastes,
due to the great success of these materials for numerous
daily applications, has caused a growing interest about
eco-efficient strategies for its appropriate management.
The global concern on the compliance for the principles
of Sustainable Development imposes severely penalty on
traditional waste management procedures based on
disposal and destruction by incineration without any
resource recovery.
The European Commission WEEE Directive promotes
the collection and recycling of such waste streams,
proposing collection taxes in function of the amount ofelectrical and electronic equipment (EEE) for eachmember states. The aim is to increase the amount of
WEEE that is appropriately treated and to reduce thevolume that goes to disposal [1]. Once the WEEE istreated in an authorized facility, various complex rejected
fractions formed by a dirty mixture of several types ofplastics (ABS, PS, PP…) and metals are produced.
Taking into account the cost and difficulty of theserejected streams separation, and the incompatibility
between the different types of polymers when mixed formechanical recycling, currently the only economicallyfeasible management option is the incineration or landfill[2]. In accordance with this, PROQUIPOL project isassessing the pyrolysis process as an alternative ofmanagement for these non-mechanically recoverable
WEEE plastics streams, with the aim of transform theinteriores libro.indd 55

waste into products suitable to be used as fuel or inpetrochemical feedstock.
Pyrolysis is a promising process that can potentially be
used to transform complex plastic waste streams to morevaluable products [3]. Only a few studies have been
carried out about the pyrolysis of real WEEE, and theinteractions between components of different nature.

2. Materials and Methods
2.1. Materials
The waste stream aim of this study is a plastic fraction
from a commercial WEEE authorized treatment facility.
The waste is a mixture formed mainly by plastics, above
91%, metals (5.3%), wood (2.1%) and other solids (seeFigure 1). In plastic fraction, the styrenics and polyolefins
are the predominant polymers (57.4% and 22.9%
respectively) while the rest of fractions correspond torubbers, films, thermosets and others (see Figure 1).

Inert
0,14
Metals5,29
Others
0,88
Wood
2,11
Paper
0,34

Fines
0,06

Plastic
91,16

Textile0,02

Film0,92

Rubber
1,25

Thermoset
0,34
Foam
0,04

Poliolefin
20,93

PVC
0,33

Styrenic
52,31

Others
15,04

Figure 1. Type of materials and polymers present in the WEEE

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6th International Symposium on Feedstock Recycling of Polymeric Materials

3. Results and Discussion

Table 2 shows high liquid yields in the case of polyolefinsmaterials, while for the styrenics the liquid yielddecreases more with ABS addition; as a consequent theformation of solid product (char) increases. Taking into
account the ash content of the WEEE waste, it organic
content is 83.8 wt%, so the real liquid yield is similar tothe obtained for the pyrolysed styrenic mixtures.
3.3 Pyrolysis liquids analysis
The characterization of pyrolysis liquids was made by thestudy of the HHV and GC/MS analysis. Figure 3 showsthe HHV results. The HHV of all the liquids is above theHHV of a common fuel oil of refinery (42.6 MJ/kg).
6050

HHV (MJ/Kg)

Also virgin polymers of PP, HDPE, ABS and PS wereused in the pyrolysis test, as reference materials to study
the interactions between them.
2.2. Pyrolysis process
The pyrolysis lab-scale experiments were carried out in a
0.5 L stainless steel fixed bed batch reactor. Low
temperature pyrolysis is aimed at the production of liquid
fractions. Previous studies carried out by the authors
indicated that 430°C and 1 h are adequate operation
conditions for treating polymeric wastes by pyrolysis.
In a typical run 50 g of the material to be tested areplaced into the reactor and sealed, then nitrogen ispassed and the system is heated to the operation
temperature, 430°C, and maintained there during 60 min.
The WEEE particle size was reduced from 5-15 mm tofeed in the reaction system.

44,346,145,4

Fuel oil

43,343,840,840,839,839,840,540,940

30
20103.1 Characteristics of the pyrolysed WEEE sample
For the moment, the selected WEEE stream is a polymer
rich e-waste without a clear recycling strategy. The
sample was provided by a Spanish WEEE recycling
facility, mainly centred in the recovery of metals. Table 1shows the elemental composition of the pyrolysedsample.
Table 1. Elemental
composition of WEEE
Elemental analysis(wt.%)
C35.0
H
7.9
N
1.5
S
<0.02O
3Cl
1.36
Br
0.71
F<0.025Ash
16.2

Figure 2. WEEE sample

Complementary physico-chemical parameters were
determined: High heating value (HHV) 33.6 MJ/kg, bulk
density 496 kg/m3 and the metal content analysis
indicated the presence of Al, Cu, Ca and Sb.
3.2 Pyrolysis experiments
The liquid, solid, and gas yields wt% obtained in thepyrolysis experiments are presented in Table 2. Theliquid and solid yields were determined by weighting theamount of each obtained, while the gas yield wasdetermined by difference.
Table 2. Pyrolysis liquid, solid and gas yields (wt%)
Material

Polymer’snatureLiquidyield, %
81.0

0.0

19.0

Polyolefins

78.9

0.0

21.1

80.0

0.0

20.0

85.2

0.1

14.7

50.4

20.7

28.9

59.8

17.1

23.1

44.3

37.3

18.5

PP
HDPE
50%PP+50%PE
PS
60%ABS+40%SB

Styrenics

40%ABS+60%SB
WEEE waste

interiores libro.indd 56

MixtureSolidyield, %Gas
yield, %0Figure 3. HHV comparison between obtained pyrolysis
products and reference fuels
In addition, GC/MS was applied to characterise thereaction liquid products by determining their compositionand distribution of hydrocarbons. The liquid products arecomplex mixtures of organic compounds. Liquids derived
from polyolefins content mainly linear hydrocarbons,
while liquids derived from styrenics content aromaticones. Compared with the results after processing WEEE
sample it is observed that the composition of liquid
products is related with the main polymer contained in
the waste.

4. Conclusions
The results have shown that the pyrolysis process is an
attractive recycling alternative for waste complex plastic
mixtures recovering liquid products and liberating
valuable solids like metals.

References[1] Directive 2002/96/EC, on waste electrical andelectronic equipment (WEEE), OJ L 37, 13.2.2003[2] W.J. Hall, P.T. Williams, Analysis of products frompyrolysis of plastics recovered from the commercial scale
recycling of waste electrical and electronic equipment, J.
Anal. Appl. Pyrolysis, 79 (2007) 375-386[3] N. Miskolczi, A. Angyal, L. Bartha, I. Valkai, Fuels by
pyrolysis of waste plastics from agricultural andpackaging sectors in a pilot scale reactor, Fuel
Processing Technology 90 (2009) 1032-1040

Acknowledgments
The authors wish to acknowledge the confidence andeconomic support of the Spanish Ministry of Educationand Science to this work by financing the PROQUIPOL
Project “Reference PID-560620-2009-4” and the courtesyof INDUMETAL RECYCLING, S.A. for providing theWEEE plastics samples used in this study.

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