Automotive Recycling in Japan - ACS Symposium Series (ACS

Chapter 5

Automotive Recycling in Japan

Emerging Technologies in Plastics Recycling Downloaded from pubs.acs.org by UNIV OF TEXAS AT AUSTIN on 08/26/17. For personal use only.

Kaoru Asakawa Materials Research Laboratory, Nissan Research Center, Nissan Motor Company, Ltd., 1, Natsushima-cho, Yokosuka 237, Japan

In Japan, the lack of sufficient landfill capacity is again generating a great deal of public interest in the question of waste disposal. Scrapped car bodies in Japan are shredded into small bits and pieces, referred to as shredder dust. The cost of disposing of that dust has skyrocketed recently,causing a problem for the automotive industry. In some areas of the country, old vehicles abandoned on the road have become a fairly common sight. These circumstances set stage for Nissan's decision to establish a Recycling Promotion Committee in August of 1990. Up to that point, each department at Nissan had carried out its own recycling effort. The reason for establishing the committee was to pull together all of those individual efforts, gather the latest information and, on that basis, try to find broad-based solutions to the problem of waste disposal. This paper focuses on the issue of how to recycle plastic waste, and will explain our thinking on this issue in terms of the technology involved and describe some of the efforts under way at Nissan to deal with this problem.

Current Situation on Scrapping Vehicle in Japan Fig.1 shows the total amount of waste generated in Japan in 1987. Approximately 70% of the ordinary waste in Japan is incinerated and then buried in landfills. The growing volume of waste in recent years has led to a shortage of incinerator capacity. As a result, some waste is now disposed of at landfills directly without being incinerated. Industrial waste accounts for more than four times the volume of ordinary waste. The waste disposal situation is growing more severe all the time. Fig.2 shows the decreasing capacity of landfills in the Tokyo metropolitan area. As you can see, the landfill capacity has been reduced by one-half in the last three years. It is becoming increasingly more difficult to find waste disposal sites in this area. As a result, some of the disposers of industrial waste are going as far as 500 kilometers away to find landfill sites and are transporting waste there for disposal. This is one reason for the soaring cost of waste disposal and it is also giving rise to various social problems. Against this social backdrop, what is the situation like for cars? Fig. 3 shows the number of new car registrations and the number of scrapped cars during the past decade. Two things that stand out here are the sharp rise in new car registrations from around 1986 and the accompanying increase in scrapped vehicles. N O T E : This chapter is based on a paper presented at the 24th ISATA symposium, Florence, May 1991. ISATA: 42 Lloyd Park Avenue Croydon CRO 5SB, United Kingdom 0097-6156/92/0513-0049$06.00/0 © 1992 American Chemical Society


EMERGING TECHNOLOGIES IN PLASTICS RECYCLING

Figure 1. Total Volume of Waste in Japan

Figure 2. Capacity of Landfills in Tokoyo Metropolitan Area

[Million/Year]

New Car Registratloi i&

—

'80

*

"~~

^T... J^....

—****** Scrapped C:ars

'85

*90

Figure 3. Number of Scrapped Cars in Japan


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In 1989, some 4,620,000 cars were scrapped. The capacity for scrapping old cars is estimated at between four to five million units. Here, too, the situation is continually becoming more severe. The scrapping of old cars begins with the recovery of valuable items, which disassemblers resell to make a living. These items include catalytic converters,parts that are still usable, and engine components and other parts with a high aluminum content. At the same time, the tires, battery, gasoline tank and other potentially dangerous parts are also removed, as they would interfere with the subsequent scrapping operation, and they are processed by a separate route. The stripped down bodies are then sent to shredding companies where they are chopped to bits by shredding machines. Iron and steel and major nonferrous metals are then separated and reclaimed. These metals are a source of income for the shredding companies which sell them to other processors. However, in many cases the shredder dust that remains can only be disposed of as landfill. (Fig.4) Fig.5 shows the increase in the total volume of shredder dust generated in Japan and the rising cost of waste disposal in the Tokyo metropolitan area. Nowadays, over one million tons of dust are generated every year. The disposal cost of that dust in the Tokyo metropolitan area ranges from about $100 to $160 dollars per ton. As I mentioned above, this rising cost is due to the diminishing capacity of landfills and to fact that waste is being transported such long distances. This has greatly affected the profitability of the shredding companies and so they are asking the disassemblers to pay part of the disposal cost. Because of this situation, the number of old vehicles being abandoned illegally on the road is increasing and this has become a social problem lately. Fig.6 shows the material components of shredder dust. Roughly, the dust is a mixture of 50% inorganic and 50% organic materials. However, in terms of volume, the percentage of them, especially plastic waste, is larger. This is one of the main reasons why disposal of shredder dust has now become a problem. Fig.7 shows the total amount of waste generated at Nissan and the various amounts that are recycled. Approximately 75% of the waste generated in our manufacturing processes is now recycled. In addition, most of the incinerators at our plants have been outfitted with advanced anti-pollution devices. Through incineration, plant waste is recycled into energy, which is used again in the vehicle manufacturing process. We also have our own landfill sites. NISSAN'S

Current

Actions

on

Recycling

In August of 1990, Nissan became the first vehicle manufacturer in Japan to set up a Recycling Promotion Committee. This committee was formed to provide a company-wide organization that could promote recycling more effectively. The committee is responsible for gathering information and for implementing activities which in the past were carried out by individual departments. Fig. 8 shows the organization of this committee. The committee is actively engaged in many different activities that go beyond just technical development efforts. Working groups have been formed to examine the infrastructure needed for recycling and to promote cooperation with organizations outside of the company, including government bodies and the Japan Automobile Manufacturers Association. In addition, we have also set up subcommittees in Europe and North America with the aim of carrying out global recycling activities. Fig.9 shows an outline of our thinking on recycling from a technical standpoint. As I mentioned above, one of the most pressing problems right now is the recycling of plastics, and that is why we decided to take up this issue first. Fig. 10 shows specific examples of plastic parts and materials that Nissan is now recycling. Many of these parts and materials are being recycled by our suppliers. We manufacture plastic bumpers and fuel tanks in-house and recycle the scrap


Catalyst Engine Road Wheel Gas Tank Tire Battery

1st Disassembler!

—

Mirror Bumper Fender Door Radio Air Con.

Buyers from Other Countries • * Car Dealers Car Owners Repair Shop

Tiodyf


2nd Disassembler

Engine T/M El. Motor] Battery Wire

AI—Resmelting Iron&Steel Rebuilt Parts

I Shredder

Nonferrous Metals Rebuilt Parts

Engine Rebui T/M Parts Asian Radiator Countries Cars

Materials Buyers

Non Iron Ferrous Steel Metals 50 - 60% 5 - 10% I I I Material Maker

r-Dust-i Plastics! Glass etc. 25 - 30% Landfill

Figure 4. Car Scrapping Process in Japan

95$/ton> Tokyo Metropolitan Area 19$/ton [Mtons] 1.0

100 [$/ton 50

1.2

Ill

0.5

76

78 80 82 84 86 88 '90

Figure 5. Total Volume of Shredder Dust and Landfill Cost in Japan

Percent by Weight

iPiâsncsW ^τeytiles^Λ^^^^^^^^^^^^^^^^^/

Percent by Volume R u ^ ^ ^ e ^ l e s ^ Ot he rs

Figure 6. Material Components of Shredder Dust


ASAKAWA

Piastres 3.2% Dirt 6.7

Paper, Wood Oil 2 . 6 % \ Shot M e t a l inder

Oil 2 . 8 %

2

1

%


Common refuses.3°/Λ

2 4 5

/ p9.7%;

Am ο υ "rit of W a s t e

Material s

et ai "l s" " " ό f " R e c vc I i η g

-RéC^BlÎîip 182,000 ton/y(74%) 246,000ton/year | — ^ i n c m e r a ^ ^ 38,000 ton/y(14%) :

^ t s p £ S à l 3 1 , 0 0 0 t o n / y ( 1 2%)

Figure 7. Waste Materials and Their Recycling at Nissan

RECYCLING COMMITTEE

Sub-COMMITTEE Member: W/G Chairmans

Public Relations (Market Reaction & Working Group Information W/G

Technical Development W/G

USA W/G

Europe W/G

Figure 8. Organization of Nissan Recycling Committee

Development of Recycling Technologies 1. Harmony between customer satisfaction and preservation of the natural environment 2. Consideration of vehicle life from design to scrappage based on a global perspective. 3. Effective use of resources and environmental protection.

Cars

C >2Uf J are Wrjj^from t h e E a r t f v j p K f return

t o it

Figure 9. Nissan's Thinking on Recycling Technologies


54


materials that are generated in the manufacturing process for these parts. Plastic materials recycled in other industries are also being used in manufacturing new vehicles. We also mark certain plastic parts with an in-house code to identify the type of material used. Fig. 11 shows some of the major technical issues that we are working on right now in connection with the recycling of plastics. Here, this paper focuses on some specific examples with respect to materials engineering. Fig. 12 shows the growing use of plastics in Nissan models and in all Japanese vehicles in general. These figures indicate the percentage of the vehicle weight accounted for by plastics. Up to now, plastic parts have been very useful because they can provide weight reductions, assurance of safety, comfort enhancement and greater design freedom - all at a reasonable cost. However, today there is a need to apply a new evaluation standard that takes recyclability into account. This standard should be applied not only in evaluating different types of plastics but also in making comparisons between plastics and other types of materials. Depending on the results of such comparisons and on whether the technologies are developed for using plastics to the best advantage, the amount of plastics used in vehicles in the future will vary considerably. One of our priority issues at Nissan is to switch to types of plastic that are easier to recycle and are more compatible with environmental concerns. The chart at the left in Fig. 13 shows a breakdown of the various types of plastic that we used in 1988. The one at the right shows a similar breakdown for the plastics used in the Nissan "PRIMERA(INFINITI G20) which we released in 1990. These figures are indicative of the positive effort we are making to switch to polypropylene, polyethylene and other types of plastic that are easier to recycle and are friendlier to the environment. We intend to continue this policy in the future and vigorous efforts are now under way to apply these environmentally friendly plastics to more advanced components. Among the plastic parts now in use, polypropylene bumpers have a relatively simply material composition. And also because of their large size, they are being targeted for recycling. Nissan first applied polypropylene to bumpers at an early date and we have built up ample technical capabilities in this area. These are the recent major results of our R&D activities concerning the technology for recycling polypropylene (1)We found that the mechanical properties and qualities of recycled PP are lowered more by the flagments of top coat (paint) than by the material deterioration or any other reasons. (2) We have succeeded in removing the top coat from bumpers whith an aqueous solution of organic salt (Aqueous Paint Decomposer), which is harmless to humans and the environment (see Fig. 14). (3)The recycled PP without the top coat, retains more than 95% of its mechanical properties when compared to the virgin one (see Fig. 15). (4) The recycled PP has the same moldability as the original. (5) The molded PP bumper, made from 100% recycled PP, is almost equal to the original bumper from the standpoint of function and quality. (Fig.14,15 are presented by Nissan at "GLOBE'92", March 19 in Vancouver) Once the recycling of bumpers begins in earnest, various grades of materials from different model years will all be collected together. If recycling is to succeed, it will be necessary to identify variations in quality accurately. In order to gather basic data for this purpose, we are now conducting an experiment in which we are recovering and examining old cars from the market on a systematic basis. At the same time, we are also taking advantage of this experiment to investigate ease of disassembly and possibilities for recycling other plastic parts. M


ASAKAWA


Recycling in Manufacturing •Parts Washer Tank, Wiper Parts, Rear Combination Lamp, Heater Case Cooler Case, Blower Case, PP Bumper, Rad. Réserver Tank •Materials PP, POM, ABS, AAS, PMMA, ASPE Application of Recycled Plastics •Parts Fusible Insulator, Floor Insulator, Cushon Pad, Door Trim Base Floor Mat,Trunk Trim, Engine Under Cover •Materials Chip PUR, PE Sheet(Agricultural Use), Waste Textiles, Waste PP Waste PVC, Kiln ashes(Paint waste) Identification of Plastic Materials by Marking '"•Parts Bumper, Rad. Grille, Fender Protector, Engine Under Cover Heater Case, Cooler Case , Blower Case, A/C Duct •Materials PP, PE, PUR, ABS, PC Figure 10. Examples o f Plastic Recycling at Nissan

1 Simplification of material composition 1 f Application of easy for recycling materials |

Environmentally friendly f Design and application material engineering Structures for I for recycled material^ easy dismantling 2f Marking) V a h i d e D e s i g n & S t r y d y i r ©

Rocyding Technology Recycling technologies for production process Recycling technologies for old cars I Material recycling technologies [ Development of alternative materials [Chemical recycling technologies

[Energy recycling by incineration 1

Figure 11. Technical Issues Involved in Plastic Recycling

o o Japanese Average • : Nissan's Case

f

· '75%

1975

1980

Maximum Case ο Recycling ' fTechnology I ο Minimum Case

1985 1990 Model Year

Figure 12. Trends of Plastics Application at Nissan

2000

EMERGING

TECHNOLOGIES


(Nissan's Average in 1988~)

[ J ! !

• ra Ξ E3

PP PVC EVA HDPE

• Orefins • ABS Ξ AAS.AES Μ PMMA

I N PLASTICS

RECYCLING

(Nissan "PRIMERA" [1990]"!

• • Β E3

PA CO PUF,PUR i PC • PF POM Π SMC/BMC i Ρ Ρ Ο , Ρ Ρ Ε " etc.

Figure 13. Proportions of Different Plastics in Nissan's Cars

Cutting Process Used Bumper

Paint-Removal Molding Process Process Aqueous Recycled VJPaint Decomposer^ Bumper

Reaction Tank

Cutter Bumper is cut into small pieces

Centrifuge

Bumper Scraps r after Paint is Removed L

Kneading Machine

Figure 14. Polypropylene Bumper Recycling Process

5. ASAKAWA


Material

Automotive Recycling in Japan Recycling

&

57

Energy Recycling

So far I have been explaining about some of our recent activities at Nissan to recycle materials. There is another important issue that we would like to consider next and that is energy recycling. Thermoplastic materials can be recycled by melting them down so that they can be reused. This process resembles the recycling of metals such as iron and aluminum. In the case of metals, the atoms are coupled only by a metallic bond. A metal can be renewed because after it has been melted it will again form a solid. However, many plastics form a solid by means of primary bonds, consisting mainly of covalent bonds, and by secondary bonds held together by intermolecular force. When these plastics are melted down during recycling, only the low-energy secondary bonds are broken and upon cooling the material will again form a solid. During their service life prior to recycling, plastics undergo deterioration because some of the primary bonds are damaged by exposure to stimuli such as light and heat. That deterioration is not repaired when they are melted again during recycling. Consequently, unlike metals, which theoretically can be renewed any number of times, plastics accumulate the deterioration they have suffered up to that point and it is recycled with them. Unfortunately, this means that the simple recycling of plastics is not a complete and permanent solution to the problem of how to dispose of them. On the other hand, since plastics are made from petroleum, it is possible to extract energy from them. This is one advantage they have over metals. Therefore, at the sametimethat we are developing technologies for recycling materials, it is also essential to consider ways of extracting energy from plastics effectively and safely. We refer to this as energy recycling and I think it is important to distinguish itfromthe simple incineration of waste. As mentioned in Fig.6, plastics account for around 27% of the shredder dust resultingfromscrapped cars. Nearly half of the remaining shredder dust consists of inorganic waste that has been contaminated by oil. This includes bits of metal that were not separated and recovered earlier, glass, sludge and other items. In that state, these materials have very little usable value and so they continue to be buried in landfills. I think that one promising way to treat this waste would be to turn it into slag by heating it at a high temperature above 1200°C. Heavy metals could then be recovered more efficiently and harmlessly. After that, the slag could be used as a material for making concrete. Fig. 16 outlines one concept for a future plastics recycling system which integrates the technological possibilities we have seen so far. It has been found experimentally that shredder dust contains about 3,500 to 4,000 kilocalories of energy per kilogram. That much energy is sufficient to turn the inorganic waste into slag. In Japan, a pilot system for energy recycling is now being tested. With this system, shredder dust is partially incinerated at a high temperature of 1300°C to transform the inorganic waste into slag. At the same time, the organic waste that is gasified by this process becomes a source of energy for the smelting furnace used to recover aluminumfromthe engines of the same scrapped cars. It is also used to supply warm water to local farmers for agricultural use. The percentage of waste that is incinerated in Japan is high and various measures have been adopted to prevent incinerator flue gas from polluting the air (Fig. 17). Research work is still under way, of course, to develop more advanced technology for removing dioxin, NOx, SOx, hydrogen chloride and other pollutants from incinerator emissions. This technology will have to be incorporated into a practical system that can be made available at a lower cost. Our ideas on recycling are incorporated in this future system for recycling automotive plastics. As much as possible, we want to recycle materials and energy and turn waste into usable resources. We hope that this can be done at a level that

58


I

1

1

1

1

1

ι

ι

ι

ι

•

A: Original PP \Tensile Elongation Ratio at Break Point>


(Reference)

Izod Impact Strength

B: Recycled PP with primer

\\\

C: Crushed Bumper with Primer and NSSS Top Coat (Reference) 0 10

1 20

30

40 50 60 70 Retention (%)

80

9 0 100

Figure 15. Mechanical Properties (at R . T . ) of O l d Bumper's P P (Elapsed Time: 3 to 5 Years)

:

;Χ %··

Shraddlng ]

New Incineration or Gasification System

Shedder Dust

[Inorganic Residue J

I

Heat ^Scrapped Cars

j Disassembly

[Scrapped Engin etc!) IAIResmelting pother Types of Energy

Steam

Electric Power Hot Water

Concrete] Mixed Plastics

Some Plastic Parts

[Chemical Recycling)-»»{Fuet)—^

Alloying p| Recycling]—(Re-pe l i e t s ) — •

4Other Parts]

LjSimplifiedL4 Plastics

-(Same Parts]

Chemical Recycling

Raw Materials (Monomer...) [—[Polymers]

Figure 16. Future Recycling System for Automotive Plastics

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is cost effective, achieves an optimum energy balance, provides reliable protection of the environment and can be accomplished within the framework of existing social systems. We plan to move ahead with our research activities aimed at achieving this goal.


0

20

40

60

80[%]

Japan USA

WÊÊM 10

Europe Belgium

40 40

Netherlands France (Germany) Italy

• I

Spain

• •

UK

•i

25

8 6

Figure 17. Rate of Waste Disposal by Incineration.

Conclusion Recycling is an activity that will be absolutely indispensable to tomorrow's society, and we arc in full agreement with the effort of developing tecnologies for recycling. This paper has outlined some of the vigorous efforts under way at Nissan to promote recycling. We continue to develop technologies for material recycling and also research for energy recycling. However, one major feature of this issue that should not be forgotten is the need for networking. Cooperation involving all types of businesses and industries is essential. RECEIVED

April 17, 1992

Automotive Recycling in Japan - ACS Symposium Series (ACS

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