PLASMA PYROLYSIS OF SCRAP TYRE - AN OPTION FOR ENERGY RECOVERY
B.Ruj1*, M. Puncochar2, M.Syc2, P.K.Chatterjee1, V.Pandey3, J.Mondal1, B.Chakraborty1
1 CSIR-Central Mechanical Engineering Research Institute (CMERI), Durgapur-713209, West Bengal, India

2 Institute of Chemical Process Fundamentals, The Academy of Sciences of the Czech Republic, Prague, Czech Republic
3Mechanical Engineering Department, Tejpur University, Assam, Indiae.mail: biswajitruj@yahoo.co.in ; bruj@cmeri.res.in
Phone: +91-343-6452156; Fax: +91-343-2544567

AbstractAutomobile tyres are nondurable goods, neither fusible nor soluble under normal conditions and cannot be remoulded into othershapes without serious degradation. Common treatments such as land filling or direct incineration (without recovery of value) not
only waste the resources but also increase the area of land with pollution. The increasing production of tyres has caused
considerable disposal problem. To explore the real potential of waste tyres for possible material and energy recovery, an efficient
strategy should be found. From a chemical point of view scrap tyres are, ideal candidates for the plasma pyrolysis process. This
process is a drastic non-incineration thermal process, which uses extremely high temperatures in an oxygen-starved
environment to completely decompose input waste material into very simple molecules. The present work describes thetreatment of tyre waste by thermal plasma under reducing condition. Combustible reformed gas (CO, H2 and hydrocarbons)
having high calorific value was recovered. The present study reveals that there is a great potential for development of thermal
plasma pyrolysis technologies applicable to tyre waste disposal management with energy recovery.
Keywords: tyre waste, plasma pyrolysis, syngas, energy

1. Introduction
As the heat content of the automobile tyre is even higher
than that of coal, they could be a source of alternate fuelfor power generation. There have been attempts to burnscrap tyres directly in coal-fired boilers for the production ofelectricity. There are, however, environmental concernsthat
must be addressed prior to burning scrap tyres because
the combustion flue gas may contain acid gases, such asNOx, CHx and SOx and heavy metals such as Hg, Zn, Cdetc. Although many experiments have been done, tyrepyrolysis processes have been far from satisfactory either
economically or environmentally. Pyrolyzing scrap tyres inthermal plasma to syngas may be an attractive option. In
plasma pyrolysis, scrap tyres are dissociated into atoms
and charged particles [1-3]. With the proper quenchingprocess, it is possible to “freeze” the chemical reaction
before unexpected substances are formed. Therefore,
Plasma pyrolysis may be an attractive alternative to get“cleaner” fuel from scrap tyres by using an economicprocess.

2. Materials and Methods
The thermal plasma was generated by a plasma torch withthe following operating conditions and was ejectedvertically through the top of the environmental chamber.

Operating conditions:Plasma generator voltage (v)Primary voltage: 380-440 v, 3 phase 50 Hz
Secondary voltage: 260-280 v
Plasma generator current: 26 amps
Arc current: 80 amps
Plasma generator power: 9.6 KVA
Working gas pressure: 50-70 PSI.
PlasmasourceWaste tyre

Plasma torch

Plasmareactorcoolingv

SyngasBlock diagram- Plasma pyrlysis system for tyre waste
The centre of the experimental set-up is the plasma
reactor. The experimental set-up consists of mainly plasma
source, plasma reactor and cooling & characterization

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013sections. Ultimate and proximate analysis of tyre waste
was carried out. The tyre wastes are gasified at highplasma temperature and a combustible gas resembling a
synthetic natural gas (syngas) is produced. The syngas
generated is passed through a heat exchanger andcharacterized by using Gaschromatograph.

3. Results and Discussion
Performance study of the developed plasma pyrolyser has
been carried out with the tyre waste as feeding material.
The major gas components of the product gas arehydrogen, carbon monoxide, methane, acetylene, ethylene
and other hydrocarbons which are high heating value
gases and combustible in nature
Proposed reaction scheme for scrap tyre pyrolysis in a dc
arc plasma
Step – 1, primary pyrolysis reactions take place and thevolatile matter is released including heavy hydrocarbons(tar), light hydrocarbons, and other gaseous components,leaving behind solid char.
Scrap tyre → char + heavy hydrocarbons + lighthydrocarbons + gas (H2 ,CO,CH4 ,C2 H2 ,C2 H4 , etc.)
Step – 2, Tar get cracked and light hydrocarbon may also
decompose
heavy hydrocarbons → light hydrocarbons + gas (H2,CO,CH4 ,C2 H2 ,C2 H4 , etc.)
light hydrocarbons → H2 + CH4 + C2H2 + C2H4 +CnHm

4. Conclusions
Plasma pyrolysis of scrap tyre was carried out in a batchreactor. The present investigation provides an option forenergy recovery with volume reduction and reduction oftoxic gases

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J.S.Chang, B.W.Gu and P.C.Looy,J.Enviro.Sci.Health, 1996. A31(7); 1781-1799.

[2]

R.R.Guddeti, R.Knight and E.O Grossmann, Ind.
Eng.Chem.Res., 2000, 39 (5); 1171-1176.

[3]

Z.Zhao, H.Huangm and C.Wu,
Chem.Eng.Technol, 2001, 24 (11); 197-1

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