Pyrolytic Oil Production from Municipal Plastic Waste and its Performance in a Diesel Engine
Mochamad Syamsiro1, Harwin Saptoadi2, Shuo Cheng1, Zainal Alimuddin3, Kunio Yoshikawa1
2

1
Department of Environmental Science and Technology, Tokyo Institute of Technology, Japan
Department of Mechanical and Industrial Engineering, Gadjah Mada University, Yogyakarta, Indonesia
3
School of Mechanical Engineering, Universiti Sains Malaysia, Penang, Malaysia
E-mail: syamsiro.m.aa@m.titech.ac.jp ; Phone: +81 45 924 5507 , Fax: +81 45 924 5518

Pyrolytic oil production from municipal plastic waste by sequential pyrolysis and catalytic reforming
processes have been studied in this paper. Three kinds of municipal plastic wastes were collected from final
disposal site and small recycling company in Yogyakarta city, Indonesia. Commercial Y zeolite and naturalzeolite 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. The experiments were carriedout at the pyrolyzer temperature of 450°C and the reforming temperature of 450°C. A preliminary dieselengine performance test has also been investigated utilizing these oils. The results show that the feedstock
type strongly affect the product yields and the quality of liquid and solid products. From HDPE waste, wecould 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.
Key Words: pyrolysis, plastic waste, natural zeolite, diesel engine

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 andcaused significant environmental problems worldwide.
Disposing of plastic wastes by landfilling is not a suitableoption due to slow degradation rates. Therefore, alternative
methods such as 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 involves the degradation of the polymeric materials
by heating in the absence of oxygen. These pyrolytic products
can be divided into a gas fraction, a liquid fraction and solidresidues [2]. However, the thermal degradation of plastics has amajor drawback such as a very broad product range and requires
high temperature. Catalytic degradation therefore provides ameans 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, the reaction temperatureand the residence time. However, the direct catalytic cracking ofplastic wastes suffers from a number of drawbacks which has
prevented its commercial success. The first relates to difficulty
to recover the catalyst after use, which increases the operationalcost. Furthermore, direct contact with plastic wastes will makecatalyst deactivate rapidly due to the deposition ofcarbonaceous matter and the poisoning effect of extraneous
elements and impurities such as chlorine, sulfur and nitrogencontaining species that maybe present in the plastic wastes [1].
Therefore, separation of catalytic reforming reaction frompyrolysis stage can be applied to overcome these problems. Thismethod has been firstly tested by Bagri and Williams [2] forpolyethylene and polystyrene using zeolite-Y and ZSM-5
catalysts. The use of other catalysts such as silica alumina andAl-MCM-41 have also been investigated by others [3]. In thispaper, we describe the pyrolysis and catalytic reforming ofmunicipal plastic waste in Indonesia over commercial andnatural zeolite catalysts in a pilot scale batch system.
２．Materials and Methods
2.1 MaterialsThe feedstocks used for these experiments were three kindsof municipal plastic wastes, i.e. polyethylene bag with (2) andwithout (1) crushing and washing, and HDPE waste aftercrushing and washing. They were obtained from final disposalsite and a small plastic recycling company in Yogyakarta city,
Indonesia. The catalysts used for these works were commercial
Y zeolite and natural zeolite. The Y zeolite was obtained fromZeolyst while natural zeolite was collected from Klaten,
Indonesia.
2.2 Pyrolytic and catalytic reforming experiments
Pyrolysis and catalytic reforming experiments were carriedout in a pilot scale two stage reactor using batch system. It
consists of the pyrolysis reactor and the catalytic reforming
reactor. The snapshot of the experimental apparatus was shownin Fig. 1. The pyrolysis reactor and the reformer were made ofstainless steel and covered with an electric heater. The
pyrolyzer`s inner diameter and height are 200 mm and 400 mm,respectively. The reformer`s inner diameter and height are 100mm and 400 mm, respectively. A shell and tube type condenser
was installed at the outlet of the reformer to separate gas andliquid products.
In these experiments, 1.6-2.6 kg of the feedstock was fed into
the pyrolysis reactor. The pyrolyzer and the reformer were thenheated up to the preset temperatures. The catalyst (100 g) wasloaded in the catalytic reforming reactor, where the pyrolysis
gas generated in the first reactor was reformed. After having
the reforming reaction, the gas was condensed into liquid
products in the condenser. Liquid products were then collectedand weighed for mass balance calculation.
The experiments were carried out at the pyrolyzertemperature of 450°C and the reforming temperature of 450°C.
The gaseous products were burned off to prevent emission fromhydrocarbon gases.

Fig. 1 The photograph of experimental apparatus
2.3 Diesel engine test
Engine tests were conducted on a four cylinder, four strokes,
and water cooled diesel engine. The experiments were done bymixing 20% of plastic oil and 80% diesel fuel.
Table 1. Technical specifications of the test engine.
Engine parameter
Specification
Type
Nissan Diesel SD22 Series
Bore (mm)83
Stroke (mm)100Compression ratio
22:1
Number of cylinder
4３．Results and Discussions
3.1 Effect of feedstocks
The product yields as the effect of the feedstocks can be seenin Fig 2. Commercial Y zeolite was used in these experiments.
PE bag 1 obtained from final disposal site still produced waterand highest portion of solid residue because of uncrushed andunwashed sample. HDPE waste produced highest liquid fraction.
However, the heavy oil fraction was still high which indicatedthe low quality of the oil.

Fig. 2 Effect of feedstocks on the product yields
3.2 Effect of catalysts
Fig. 3 shows the product yields obtained from the sequential
pyrolysis and catalytic reforming of municipal plastic wastes
as the effect of catalysts. It can be seen that the pyrolysis only
produced highest liquid fraction. The presence of catalyst
reduced the liquid fraction and increased the gaseous fraction.
Pyrolysis with natural zeolite catalyst produced higher liquid
product compared with Y zeolite catalyst.
3.3 Solid residues
The proximate analysis and heating value of the solid residue
produced are shown in Table 2. PE bag 1 produced high ash
content of solid product due to the impurities which reduce theheating value of the product. However, plastic pyrolysis
produced higher heating value solid products than biomass andlow rank coal. Therefore, they can be used either for blending
with biomass and coal or for single fuel.

Fig. 3 Effect of catalysts on the product yields
Table 2. 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 (MJ/kg)
19.80
26.35
3.4 Diesel engine performance
Power variation curves of all test fuels were presented in Fig.
4. It can be seen that power values of all fuels showed
increasing trends with respect to increase in engine speed.
However, they have no linearity due to the increase inmechanical losses.

Fig. 4 Variation of engine power with engine speed
４．Conclusions
Sequential pyrolysis and catalytic reforming of Indonesianmunicipal plastic wastes have been done over Y and naturalzeolite catalysts. The feedstock type strongly affect the productyields and the quality of liquid and solid products. HDPE waste
produced both the highest liquid fraction and very high heating
value solid product. The catalyst presences reduced the liquid
fraction and increased the gaseous fraction. Pyrolysis withnatural zeolite catalyst produced higher liquid productcompared with Y zeolite catalyst. Diesel engine tests show thatblending diesel fuel with 20% plastic oil gave similar
performance with those of single diesel fuel.
Acknowledgements
The authors would like to thank AUN/SEED-Net JICA for thefinancial support under The Collaborative Research withIndustry (CRI) Program.
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