SEQUENTIAL PYROLYSIS AND CATALYTIC REFORMING OF MUNICIPAL PLASTICWASTE IN A PILOT SCALE REACTOR
M. Syamsiro1, H. Saptoadi2, S. Cheng1 and K. Yoshikawa1,*
1Department of Environmental Science and Technology, Tokyo Institute of Technology, G5-8, 4259 Nagatsuta, Midori-ku,

Yokohama 226-8502, Japan
2Department of Mechanical and Industrial Engineering, Gadjah Mada University, Jl. Grafika 2 Yogyakarta 55281 Indonesia

E-mail:syamsiro.m.aa@m.titech.ac.jp ; Phone: +81 45 924 5507 , Fax: +81 45 924 5518

Abstract
The performance of sequential pyrolysis and catalytic reforming of municipal plastic waste have been studied in thispaper. Three kinds of MPW were collected from final disposal site and small recycling company in Yogyakarta city,Indonesia. Commercial Y zeolite and natural zeolite catalysts were used in this study. The batch-type pilot scale reactor
with the capacity of 1.6-2.6 kg feedstock was used and 100 g of catalyst was loaded in the reforming reactor. Theexperiments were carried out at the pyrolyzer temperature of 450°C and the reforming temperature of 450°C. The results
show that the feedstock type strongly affect the product yields and the quality of liquid and solid products. From HDPE
waste, we could produce both the highest liquid fraction and very high heating value solid product. The catalyst presence
reduced the liquid fraction and increased the gaseous fraction. Pyrolysis with natural zeolite catalyst produced higher
liquid product compared with Y zeolite catalyst.

Keywords: pyrolysis, catalytic reforming, municipal plastic waste, catalyst, natural zeolite

1. Introduction
A significant growth of plastics consumption in modern
life has resulted in an increased production of plastic
wastes. Thus, plastic wastes have become a major
stream in solid waste and caused significant
environmental problems worldwide. Disposing of plastic
wastes by landfilling is not a suitable option due to slow
degradation rates. Therefore, alternative methods suchas chemical or feedstock recycling which involves
pyrolysis of plastics into fuel have been introduced not
only for wastes reduction but also for fuel production.
Pyrolysis or thermal cracking involves the degradation of
the polymeric materials by heating in the absence ofoxygen. These pyrolytic products can be divided into agas fraction, a liquid fraction and solid residues [2].
However, the thermal degradation of plastics has a major
drawback such as a very broad product range andrequires high temperature. Catalytic degradation
therefore provides a means to address these problems.
The direct catalytic cracking has been used widely due toseveral advantages, mostly in terms of the energy
efficiency, with regards to the use of the reactor, thereaction temperature and the residence time. However,the direct catalytic cracking of plastic wastes suffers froma number of drawbacks which has prevented its
commercial success. The first relates to difficulty torecover the catalyst after use, which increases theoperational cost. Furthermore, direct contact with plastic
wastes will make catalyst deactivate rapidly due to thedeposition of carbonaceous matter and the poisoning
effect of extraneous elements and impurities such as
chlorine, sulfur and nitrogen containing species thatmaybe present in the plastic wastes [1]. Therefore,
separation of catalytic reforming reaction from pyrolysis
stage can be applied to overcome these problems. Thismethod has been firstly tested by Bagri and Williams [2]for polyethylene and polystyrene using zeolite-Y andZSM-5 catalysts. The use of other catalysts such as silica
alumina and Al-MCM-41 have also been investigated byothers [3]. In this paper, we describe the pyrolysis andcatalytic reforming of municipal plastic waste in Indonesia
over commercial and natural zeolite catalysts in a pilot
scale batch system.

2. Materials and Methods
Materials
The feedstocks used for these experiments were threekinds of municipal plastic wastes, i.e. polyethylene bagwith (2) and without (1) crushing and washing, and HDPE
waste after crushing and washing. They were obtained
from final disposal site and a small plastic recycling
company in Yogyakarta city, Indonesia. The catalysts
used for these works were commercial Y zeolite andnatural zeolite. The Y zeolite was obtained from Zeolyst
while natural zeolite was collected from Klaten, Indonesia.
Pyrolysis and catalytic reforming experiments
Pyrolysis and catalytic reforming experiments werecarried out in a pilot scale two stage reactor using batchsystem. It consists of the pyrolysis reactor and thecatalytic reforming reactor. The snapshot of theexperimental apparatus was shown in Fig. 1. The
pyrolysis reactor and the reformer were made of

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013

stainless steel and covered with an electric heater. The
pyrolyzer`s inner diameter and height are 200 mm and400 mm, respectively. The reformer`s inner diameter andheight are 100 mm and 400 mm, respectively. A shelland tube type condenser was installed at the outlet of thereformer to separate gas and liquid products.
In these experiments, 1.6-2.6 kg of the feedstock was fed
into the pyrolysis reactor. The pyrolyzer and the reformer
were then heated up to the preset temperatures. The
catalyst (100 g) was loaded in the catalytic reforming
reactor, where the pyrolysis gas generated in the firstreactor was reformed. After having the reforming
reaction, the gas was condensed into liquid products inthe condenser. Liquid products were then collected andweighed for mass balance calculation.
The experiments were carried out at the pyrolyzer
temperature of 450°C and the reforming temperature of450°C. The gaseous products were burned off to prevent
emission from hydrocarbon gases.

Fig 1. The snapshot of experimental apparatus

3. Results and Discussion
Effect of feedstocks
The product yields as the effect of the feedstocks can beseen in Fig 2. Commercial Y zeolite was used in theseexperiments. PE bag 1 obtained from final disposal sitestill produced water and highest portion of solid residue
because of uncrushed and unwashed sample. HDPE
waste produced highest liquid fraction. However, theheavy oil fraction was still high which indicated the low
quality of the oil.

that the pyrolysis only produced highest liquid fraction.
The presence of catalyst reduced the liquid fraction andincreased the gaseous fraction. Pyrolysis with naturalzeolite catalyst produced higher liquid product comparedwith Y zeolite catalyst.

Fig 3. Effect of catalysts on the product yields
Solid residue
The proximate analysis and heating value of the solid
residue produced are shown in Table 1. PE bag 1
produced high ash content of solid product due to theimpurities which reduce the heating value of the product.
However, plastic pyrolysis produced higher heating value
solid products than biomass and low rank coal. Therefore,
they can be used either for blending with biomass andcoal or for single fuel.
Table 1. Proximate analysis of solid residue.
Composition (wt%)
PE Bag 1
HDPE waste
Moisture
1.12
1.74
Volatile matter
35.29
58.56
Fixed carbon
14.13
8.59
Ash
49.47
31.11
Heating value
19.80
26.35
(MJ/kg)

4. Conclusions
Sequential pyrolysis and catalytic reforming ofIndonesian municipal plastic wastes have been done
over Y and natural zeolite catalysts. The feedstock typestrongly affect the product yields and the quality of liquidand solid products. HDPE waste produced both thehighest liquid fraction and very high heating value solid
product. The catalyst presences reduced the liquid
fraction and increased the gaseous fraction. Pyrolysis
with natural zeolite catalyst produced higher liquid
product compared with Y zeolite catalyst.

ReferencesFig 2. Effect of feedstocks on the product yields
Effect of catalysts
Fig. 3 shows the product yields obtained from thesequential pyrolysis and catalytic reforming of municipal
plastic wastes as the effect of catalysts. It can be seen

[1] J. Aguado, D.P. Serrano, G.S. Miguel, M.C. Castro,and S. Madrid. Journal of Analytical and Applied
Pyrolysis 79 (2007) 415-423.
[2] R. Bagri and P.T. Williams. Journal of Analytical andApplied Pyrolysis 63 (2002) 29-41.
[3] G.S. Miguel, D.P. Serrano, and J. Aguado. Ind. Eng.
Chem. Res. 48 (2009) 8697-8703.

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)New Delhi, India, 23-26 October 2013