PARTⅠ PYROLYSISCURRENT ISSUES OF OIL RECLAMATION SYSTEMFOR RECYCLING MUNICIPAL WASTE PLASTICCONTAINING PVC AND PET IN JAPANBeili Wu*, 1 Masaaki Fukushima, 2 Keiji Wakai, 2 Hidetoshi Ibe,1 Seiichiro Ito 2
1Water & Environmental Process Engineering Department, Toshiba Corporation,
1-1 Shibaura 1-Chome, Minato-Ku, Tokyo 105-8001, Japan
2Sapporo Plastics Recycling CO., LTD., 45-57, Nakanuma-Cho, Higashi-Ku,
Sapporo 007-0890, Japan
E-mail: beili.wu@toshiba.co.jp

Abstract: The oil reclamation system for recycling municipal waste plastics in Sappproplastic recycle Co. LTD. (SPR) has been operated commercially for near ten years by whichmore than 67,000 ton waste plastics had been recycled even though polyvinyl chloride (PVC)
and polyethylene terephthalate (PET) are contained. As a result, SPR has achieved highrecycling rate about 90% of recycled products. In addition, hydrocarbon oil has been
produced as a by-product which can be used as the raw material for chemical industrial plant.
Moreover, cascade recycle which chemical recycle (CR) will be done for selected waste
plastics mixed with material recycle (MR) residues after material recycle has been studied
since 2008. This paper reports the current issues of oil reclamation system for recycling
municipal waste plastics in Japan.
1. Introduction
1.1 Waste plastic recycling in Japan
In 2007, the domestic plastic waste in Japan has reached total 9.94 million tons including
5.02 million tons of household waste and 4.92 million tons of industrial waste. Among those,about 7.22 million tons (73%) are reutilized as materials, fuels, electricity and thermal supply
etc. However, 2.71 million tons (27%) were incinerated or land filled [1]. The quantity
recycled from the plastic containers and wrapping among the household waste plastic, hasreached to 380,000 tons. Under the Container and Packaging Recycling Raw in Japan, about
40% were processed by material recycling operation (called MR, that waste plastics are as theraw materials for plastic products.) and 60% were processed by chemical recycling operation(called CR, like liquefaction, gasification, coke oven, blast furnace etc.). [2]- 89 -450,000t

700,000t

400,000t

680,000t

350,000t

660,000t

300,000t

640,000t

250,000t

620,000t

200,000t

600,000t150,000t

580,000t

100,000t

560,000t

50,000t

540,000t

0,t

T otalC R ・M R

The 5th ISFR (October 11-14, 2009, Chengdu, China)

520,000t

2005

2006

2007

CR2008

MR

2009

Total

Fig.1 The bid Amount of municipal waste plastics
by MR and CR and their total amount
However, the bid amount of MR and CR respectively showed in Fig.1 suggests that MR
has been holding the more bid amount of municipal waste plastic these 3 years. In 2008, thebid amount of MR reached 400,000t, a maximum amount, while this of CR was 255,000t.
Because of recycling policy drawn by Japanese government, the recycling method of MR is
holding the dominate position though lower recycling rate it reached.
1.2 Liquefaction System outline
In 2000, Sapporo Plastics Recycling Co., Ltd. (SPR) was established in Sapporo-shi,
Hokkaido and started operation with 14,800t/y capacity. Up to now, it has been operated
commercially for near ten years. There have been 76,800t waste plastics treated by SPR
which is shown in Fig.2. Last year (2008), an investigation of cascade recycling* was carriedout. (*Cascade recycling is a new recycling model that MR wastes are processed by CR(liquefaction) mixed with municipal waste plastic.)
16,000t

92,041t
76,810t

80,000t

67,385t

70,000t

57,940t

10,000t

60,000t

47,853t

8,000t50,000t36,189t

6,000tT otal

12,000t
A m out of each year

100,000t
90,000t

14,000t

40,000t
30,000t

4,000t20,000t
2,000t10,000t

H okkaido except Sapporo

M R residue

2009(Plan)

2008

720
0

2006

200S apporo

20050t40t

T ohoku area

Totalsince 2000

Fig.2 The Achievement of SPR
Fig.3 shows the composition of waste plastic each year from 2000 to 2008. Polyvinylchloride (PVC) and polyethylene terephthalate (PET) which are unsuitable for liquefaction arecontained. Liquefaction process functional outline of SPR is shown in Fig.4. The liquefaction
plant is operated with a unique characteristic of installed dechlorination process. Throughheating plastic pellets at 350℃ by electric heater, they are melt and hydrochloric gas yielded- 90 -PARTⅠ PYROLYSIS
by thermal decomposition of PVC is carried over and hydrochloric acid is produced byabsorbing into water. With this process, reclamation oil is gained with less chlorine. Moreover,benzoic acid (C6H5OOH) which occurred by the thermal decomposition of PET caused
corrosion and clogging. The operational troubles caused by PET was solved by adding
hydrated lime (Ca(OH)2) to plastic pellets [3,4]. Presently SPR is maintaining safety andstability in operation. Almost all of waste plastics except foreign material and water have been
reclaimed and recycled. In 2008, 9,425t waste plastics were treated. The hydrocarbon oil as
recycled product with 51wt%, the gaseous fuel with 13wt%, the solid fuel with 20wt%, theheavy oil sludge with 5wt% and the hydrochloric acid as by-product with 1wt% werereclaimed respectively. Aluminum, used as packages of boil-in-the-bag foods, is also started
recycling.
16%

100%
90%

14%

70%
10%

60%

8%

50%

３Ｐ

ＰＶＣ、ＰＶＤＣ、ＡＢＳ、ＰＥＴ

80%
12%

40%

6%

30%
4%
20%
2%

10%

0%

0%
2000
2001
ＰＶＣ

2002
ＰＶＤＣ

2003

2004
ＡＢＳ

2005
2006
2007
2008
ＰＥＴ
3P (P E+P P+P S )Fig.3 The composition of municipal waste plastic
Neutralizing agenｔ
for Sale

HCL
AbsorbingHCL Process
DeDe-HCl incinerator

HouseholdHousehold
Waste
WastePlastics
Plastics

60℃
60℃
⇒

14,800t/year

Off-Gas

1200℃
1200℃ OilDistillation
350℃
350℃
Process

Pretreatment
ProcessPellet
Ca(OH)2

Foreign material
Water

Dechlorination
Process

Feedstock
Recyclingfor Sale

Hx
Process Use
120℃ 120℃⇒40℃
FuelHxPyrolysis
Medium oilfor Sale
Process450⇒
450⇒120℃
120℃ 200℃ 200℃⇒40℃
Thermally
280⇒80℃
EjectorCogeneration
degraded gas
Heavy oil Hx
Fuel
350～
350～450℃
450℃
280℃
Light oil

350℃
350℃

Products
Residue
By-Products

Process Use

SludgeSolid Fuel Production Process （Pellet)

Fuelfor Sale

Hx:Hx: Heat Exchanger
Solid Fuelfor Sale

Fig.4 SPR process functional outline

1.3 Characteristic of dechlorination process
Fig.5 shows the characteristic of dechlorination process. Content of chlorine bypercentage formed to hydrochloric acid and dropped to residue are compared in the presenceof Ca(OH)2 or not. In the case of 0% Ca(OH)2 added, content of chlorine had a highpercentage as 96wt%. Since adding Ca(OH)2 to pellets before dechlorination process on
December 24, 2000, content of chlorine in hydrochloric acid has decreased. On the other hand,- 91 -The 5th ISFR (October 11-14, 2009, Chengdu, China)
content of chlorine in thermally degraded residues has increased. It suggests that hydrogenchlorine removed in dechlorination process reacts to Ca(OH)2 and CaCl2 is formed anddropped to pyrolysis process. Inadequate addition of Ca(OH)2 caused corrosion and clogging
by increase of benzoic acid and pH of reclamation oil decreased. However, excessive additionof Ca(OH)2 caused increase of thermally degraded residue. So the quantity of Ca(OH)2 added
is controlled by watching the pH of reclamation oil.

C ontent of C hlorine by percentage

100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
0%

1%

2%
3%
4%
5%
The R ate of Lim e addition

C hlorine fom ed to H C l

6%

7%

C hlorine dropped to R esidue

Fig.5 Characteristic of dechlorination process

2. Cascade recycling
A discussion about improvement of plastic package and container recycling is held in
2007. As a result, a combination of material recycling and chemical recycling could offset thedisadvantage of one particular recycling method. [5]As mentioned, cascade recycling is a new recycling combination that MR wastes areprocessed by CR (liquefaction) mixed with municipal waste plastic. In 2008, an investigationof cascade recycling was carried out by SPR. The concept of cascade recycling is shown inFig.6.
Local Sorting Facilities
Waste plastics

Foreign Material（Incineration, Landfill)

Material Recycling (MR)
ProductsIW
MR Wastes（40～50%） About 3,800t
IW

About 5,600t

Liquefaction (CR)
Products

Residue（2%）2%）
IW**IW: Industrial wastes

Fig.6 Process of cascade recycling- 92 -PARTⅠ PYROLYSIS
Through material recycling method, there are still 40~50% plastic wastes which areunsuitable to be reproduced as a raw material. They are accepted by SPR to process byliquefaction mixed with municipal waste plastics. Almost all of waste plastics except foreignmaterial, other inadequate plastics and water has been reclaimed and recycled. There only 2%of residues need thermally recycling or landfill as the industrial wastes. So cascade recycling
is considered as an efficient recycling combination and contribute to local feed stockrecycling.
However, since PVC and PET occupied highly in MR wastes, an effect of the quantity ofmixed MR wastes on the process of liquefaction and the quality of reclamation oil isdiscussed as followed.
2.1 An effect of the quantity of MR wastes
2.1.1 Corrosion troubles (value of pH)
Fig.7 shows the relationship between

9.5

100%

pH of R eclam ation O il90%
the value of pH of reclamation oil and the
8.5
80%
8.0
content of MR wastes*. The value of pH
70%
7.5
60%
went down to 6.5 or less when 45% or
7.050%
6.5
more MR wastes were mixed. This is40%
6.030%
because that benzoic acid (C6H5OOH)
5.5
20%
5.0
which caused corrosion troubles was10%
4.5
increased occurred by the thermal
4.00%
pH of R eclam ation O il
C ontent of M R W astes
decomposition of PET. Once thepercentage of MR waste was controlled byFig.7 relationship between the value of pH ofless than 40%, value of pH was up from 7
reclamation oil and the content of MR wastes
to 8 that corrosion troubles do notoccurred.(*Content of MR (%) = Quantity of MR waste/(Quantity of MR + Quantity of wasteplastic) )2008/4/1

2008/5/1

2008/5/11 2008/5/21 2008/5/31 2008/6/10 2008/6/20 2008/6/30

700kg/t
600kg/t
500kg/tY ields

2.1.2 Yields of reclamation oil
Fig.8 shows the yields ofreclamation oil, gas and residue when
1t of mixed waste plastic are treated bySPR. It suggests that yields ofreclamation oil are decreased while
those of gas and residue are increased
with the increasing of the quantity ofMR wastes. Y. Sakata’s literature[6]shows that yields of reclamation oil aredecreased while those of gas and2008/4/11 2008/4/21

400kg/t
300kg/t
200kg/t
100kg/t
0kg/t
30%

32%

34%

36%

38%
40%
42%
44%
C ontent of M R W astes

R eclam ation O il

R esidue46%

48%

50%

G as

Fig.8 Yields of reclamation oil, gas and residue- 93 -C onten of M R w astes

9.0

The 5th ISFR (October 11-14, 2009, Chengdu, China)
residues are increased in the presence of PVC, and the same results with in the presence ofPET. Since PVC and PET occupied highly in MR wastes, our investigation show the sametendency. The quantity of MR waste mixed is controlled to gain more reclamation oil.

2.2 Chlorine in reclamation oil
Fig.9 shows chlorine in reclamation oil separated to heavy oil, medium oil and light oil.
They have little quantity of chlorine (<100mg/kg (ppm)) and maintain high quality ofreclamation oil.
C hlorine in Reclam ation O il
1009080
C hlorine(m g/kg)

7060
5040302010H20.
H 2 1.1
0.1
H 2 .210.2.1
H2 00.
H 2 3.1
0.3
H 2 .210.4
H 2 .100.4
H 2 .30
0.5.2
H2 00.
H 2 6.90.6
H 2 .290.7.1
H2 90.8
H 2 .80.8
H 2 .280.9
H 2 .170.
H 2 10.70.1
H 2 0.270.1
1
H 2 .160.
H 2 12.60.12.260

Light O il(m g/kg)

M edium O il(m g/kg)

Heavy O il(m g/kg)

Fig.9 Chlorine in reclamation oil separated to heavy oil, medium oil and light oil.
2.3 Assessment of cascade recycling
Though the investigation of cascade recycling, it is demonstrated that cascade recycling
is an efficient recycling combination and contribute to local feed stock recycling. However, italso shows the tendency that when MR wastes were mixed more than 40%, (a) the value ofpH of reclamation oil went down, (b) corrosion troubles occurred, (c) the more MR wastes
mixed, the less yields of reclamation oil we had. If the quantity of MR wastes keeps less than
40%, SPR is able to be operated safety and stability.
3. Conclusion
Through its technological improvements and operational know-how, SPR has been able
to process the municipal waste plastics in almost all grades in qualities that contained PVC
and PET without trouble. SPR can also process the waste plastics from material recyclers ormechanical recyclers and a more efficient recycle of waste plastics can be done combining
mechanical and chemical recycling.
SPR has been able to recycle almost all except the water and the foreign material and has
achieved a very high recycling rate such as 90% in 2008. Since PR is a commercial plant, we
also do efforts on the improvement of productivity that the quality of by-products areguaranteed, including chlorine contained less than 100ppm, Sulfur contained less than 0.2%
and Nitrogen contained less than 0.2%. In this year (2009), it is challenging the full capacity- 94 -

PARTⅠ PYROLYSIS
operation that about 15,000t municipal waste plastics are waiting to be recycled andreclaimed.
On the other hand, cascade recycling which is an efficient recycling combination ofmaterial recycling and chemical recycling and contribute to local feed stock recycling has
been demonstrate in 2008 by SPR. If the quantity of MR wastes keeps less than 40%, SPR isable to be operated safety and stability.
References[1] Plastic Waste Management Institute,
http://www2.pwmi.or.jp/siryo/flow/flow_index.htm in Japanese[2] The Japan Containers and Packaging Recycling association,
http://www.jcpra.or.jp/recycle/index.html in Japanese[3] M. Shioya, K. Wakai, M. Fukushima, H. Ibe; The 4th ISFR, 2007, 109-117.
[4] M. Fukushima, M. Shioya, K. Wakai, H. Ibe; Journal of Material Cycles Waste
Management, 2009, 11, 11–18.
[5] Ministry of the Environment Government of Japan
http://www.env.go.jp/council/03haiki/yoshi03-15.html in Japanese[6] Y. Sakata, M. A. Uddin, et al.; Polymer Degradation and Stability, 1996, 53, 111-117.

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