Thermal Conversion of Solid Wastes and Biomass - ACS Publications

39.2. 39.2. * Test recipe of rubber compounds. ** PP test. SBR 1502. 100 parts. Zinc oxide. 5 ". Stearic acid. 2. 11. Sulfur. 2.2 ". Accelerator MBTS...
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40 Pyrolysis Process for Scrap Tires SHIGEO KAWAKAMI, KIMIO INOUE, HIDEKI TANAKA, and TAMIHARU SAKAI

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Kobe Steel, Ltd., Mechanical Engineering Research Laboratory, 1-Chome, Fukiai-Ku, Kobe, Japan

The number of scrap tires in Japan in 1977 was estimated to be approximately 47 million with a total weight of 550 thousand tons. Although some of them are reused as reclaimed rubber, re­ capped tires, etc., it is difficult to recycle a l l of the scrap tires by the usual methods, therefore, there is a demand for new recycling systems for scrap tires. Kobe Steel, Ltd. formerly developed a new process for produc­ ing powdered rubber and constructed an actual plant with a capa­ city of 7,000 ton per year in Osaka in 1976 (l,2). The powdered rubber is used as shock absorbing material for railway beds or as a f i l l e r for rubber products. Several pyrolysis processes using reactors such as a fluidiz­ ed bed (3), a shaft furnace, an extruder and a rotary kiln have also been studied in Japan. Pyrolysis using a rotary kiln has been studied since 1973 (4). A pilot plant test was finished in 1976, and an actual plant with a capacity of 7,000 ton per year has been constructed at Sumitomo Cement Co., Ltd. in ΑΚO City, Hyogo Prefecture, in 1979 (1). The plant will recover fuel o i l and carbon black from the scrap tires. I.

Process Flow.

An outline of the process flow from crushing and pyrolysis of the scrap tires to refining of char into carbon black is shown in Fig. 1. The figures in the parentheses in Fig. 1 show the material balance obtained from the pilot plant tests. The ratio of the re­ covered products changes according to the pyrolysis temperature as shown in Fig. 2. The main products are char and oil, which amount to approximately one third and one half of the total products re­ covered, respectively. Though the rate of pyrolysis increases at higher temperatures, the pyrolysis temperature has to be kept under 600°C in order to get the char from which high quality car­ bon black can be produced. 0-8412-0565-5/80/47-130-557$05.00/0 © 1980 American Chemical Society

In Thermal Conversion of Solid Wastes and Biomass; Jones, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1980.

In Thermal Conversion of Solid Wastes and Biomass; Jones, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1980.

1

1

2

4

1

W

Na S0 ί ! Solution ' J L

a

s

t

e

,

Stack

Desulfurizing

ψ_ _

NaOH

(1000 Kg)

Scrap Tires

G a s i



.

± Steel Figure 1.

(50 Kg)

Shredding

^

Pulverizingh^Pelletizing

(20 Kg)

(400 Kg)

(5 Kg)

L

Heavy Oil

j Carbon < Sludge_|

Quenching

Flow sheet of the pyrolysis plant

Carbon

Reheating

Magnetic Separation

Char

Pyrolysis

( 60 Kg )

Downloaded by UNIV OF QUEENSLAND on November 1, 2015 | http://pubs.acs.org Publication Date: August 29, 1980 | doi: 10.1021/bk-1980-0130.ch040

(340 Kg)

Carbon Black

(100 Kg)

> α

Η W

03

1

Ο C/3 Ο r

2!

δ


r ο ο

X w

Η

Downloaded by UNIV OF QUEENSLAND on November 1, 2015 | http://pubs.acs.org Publication Date: August 29, 1980 | doi: 10.1021/bk-1980-0130.ch040

KAWAKAMI ET AL.

559

Pyrolysis Process for Scrap Tires

60

0 I

1

500

1



600 TEMPERATURE

Figure 2.

t

TOO

t _

800

(°C)

Effect of the pyrolysis temperature on the ratio of recovered products (PP test)

In Thermal Conversion of Solid Wastes and Biomass; Jones, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1980.

560

THERMAL CONVERSION OF

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II.

SOLID WASTES AND

BIOMASS

Research and Development

To examine the p y r o l y s i s r e a c t i o n o f the scrap t i r e s , p u l ­ v e r i z e d scrap t i r e s were heated i n a quartz tube by an e l e c t r i c furnace (h). Then the continuous p y r o l y s i s t e s t p l a n t s i n Table I were constructed t o get the engineering data r e q u i r e d f o r the design o f an a c t u a l p l a n t . The p i l o t p l a n t i s shown i n F i g . 3. The longest p e r i o d of continuous operation of the p i l o t p l a n t was 120 h r s . In the mini p l a n t t e s t s (MP Test) scrap t i r e s shredded i n t o pieces about 10 mm i n s i z e were used. In the p i l o t p l a n t t e s t s (PP Test) scrap t i r e s shredded i n t o p i e c e s about 50 mm i n s i z e as w e l l as the f i n e shredded t i r e s were used. Table I .

Test p l a n t s f o r the p y r o l y s i s process

Dimensions of the k i l n Heating

system

Feeding

system

Discharge

system

Capacity

(Kg/H)

(mm)

P y r o l y s i s Bench Test (MP t e s t )

P i l o t Plant Test (PP t e s t )

100^ χ 1,200*

k25