Review Article Biocrude Production through Pyrolysis of ...downloads.hindawi.com/archive/2014/386371.pdf · transportedtowhereitcanbemostpro cientlyutilized.Tyre pyrolysis can be

Review ArticleBiocrude Production through Pyrolysis of Used Tyres

Julius I Osayi1 Sunny Iyuke1 and Samuel E Ogbeide2

1 School of Chemical and Metallurgical Engineering University of the Witwatersrand 1 Jan Smut AvenueBraamfontein Private Bag 3 Johannesburg 2050 South Africa

2Department of Chemical Engineering Faculty of Engineering University of Benin PMB 1154 Benin City Edo State Nigeria

Correspondence should be addressed to Julius I Osayi ojgrantsyahoocom

Received 27 January 2014 Revised 16 April 2014 Accepted 17 April 2014 Published 15 May 2014

Academic Editor Murid Hussain

Copyright copy 2014 Julius I Osayi et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

A review of the pyrolysis process of used tyre as a method of producing an alternative energy source is presented in this paper Thestudy reports the characteristics of used tyre materials and methods of recycling types and principles of pyrolysis the pyrolysisproducts and their composition effects of process parameters and kinetic models applied to pyrolysis From publications theproximate analysis of tyre rubber shows that it is composed of about 286 wt fixed carbon 62wt volatile material 85 wt ashand 09wt moisture Elemental analysis reveals that tyre rubber has an estimated value of 82wt of C 8 wt of H 04 wtof N 13 wt of S 24 wt of O and 59 wt of ash Thermogravimetry analysis confirms that the pyrolysis of used tyre atatmospheric pressure commences at 250∘C and completes at 550∘CThe three primary products obtained from used tyre pyrolysisare solid residue (around 36wt) liquid fraction or biocrude (around 55wt) and gas fraction (around 9wt) Although thereis variation in the value of kinetic parameters obtained by different authors from the kinetic modeling of used tyre the process isgenerally accepted as a first order reaction based on Arrhenius theory

1 Introduction

One of the main challenges of modern society is the risingrate of solid waste generated by manrsquos activities which haspoised a major environmental concern [1ndash3] The disposal ofused tyres and other polyisoprene based products is a largefraction of such problems as 13 billion tyres are estimatedto reach their end of life cycle annually worldwide [4ndash9]This is because of their excellent properties which have madethem useful in all areas of human life [10] However theseexcellent properties also place them at a disadvantage [3 1112] as they are not biologically degradable leading to problemswith their disposal [2 7 11 13ndash16] Over the years landfilland open dumping (stock piling) were the common waysin handling the problem of used tyres However landfillstake up valuable land space due to the bulky nature of tyreswhich cannot be compacted neither does it degrade easily[7 11 17ndash19] Dumped used tyres in massive stockpiles donot only occupy a large land space but also serve as a potentialhealth and environmental hazard due to the possibility ofa fire outbreak with high emissions of toxic gases and as

a breeding ground for disease carrying vectors [7 15 16 2021] Despite other tyre recycling options such as reclaiminggrinding incineration retreading and so forth being usedthese processes have their setback and do not fully utilizeused tyres as an excellent material for energy recovery [8 22]For this reason pyrolysis has received renewed attention asthe process conditions can be optimized to produce highvalued products [4ndash6 11 23ndash27] Pyrolysis mainly involve thedecomposition of polyisoprene materials to low molecularweight component at high temperature (250∘Cndash900∘C) inan inert atmosphere [3 7 22 28] The process being anexcellent energy recovery route can be performed underatmospheric or reduced pressure It is an environmentallyfriendly technique to thermally decompose a wide variety ofwastes including used tyres [2 4 6 11 15 16 20 27 29ndash44] The three basic products of pyrolysis are solid residue(char) liquid (biocrude) and gases [6] Solid residue may beused in the manufacture of activated carbon reinforcementin rubber industry or as solid fuel The pyrolytic liquid canserve as replacements for conventional liquid fuel due to itshigh gross calorific value of about 41ndash44MJkg It can also be

Hindawi Publishing CorporationJournal of CatalystsVolume 2014 Article ID 386371 9 pageshttpdxdoiorg1011552014386371

2 Journal of Catalysts

used as petroleum refinery feedstock or a source of chemicalsfor wide industrial applications Gaseous fraction can be usedas fuel or as a source of energy for the pyrolysis process[22 28 29 45ndash49]

This paper presents a literature review of the pyrolysisprocess with a focus on the characteristics of used tyresmaterials and methods of recycling types and principlesof pyrolysis properties of the pyrolysis products effects ofprocess parameters and kinetic models applied to pyrolysis

2 Used Tyres

Used tyres also referred to as waste tyres can be definedas tyres that have expired as a result of exceeding theirproduction life span or are no longer safe for usage dueto defects such as degradation of its physical composi-tionstructure from use and cannot be retreaded It is one ofthe most challenging hazardous solid wastes facing modernsociety particularly in developing countries [3 10 11] It isestimated that the EU Japan and USA generate 6 times 106 tonsof waste tyres annually [6 22 23 46 64] According to areport 160000 tons of waste tyres are generated in SouthAfrica annually and up to 28 million used tyres are dumpedunlawfully or burnt [70] This figure is projected to increaseby 93 million yearly [70] The nonbiodegradable nature ofthis polymer material makes its disposal difficult Disposalby massive stockpiling and landfilling is one of the commonways of handling waste tyre but this requires a large space asthe volume of tyres cannot be compactedThese also poise thedanger of the possibility of fire outbreak with the emission ofharmful gases [1 7 19 21 22 64 71ndash75]

21 Methods of Recycling of Used Tyres The various methodsin which used tyres are recycled are discussed below

211 RetreadingMethod Retread also referred to as ldquoremoldrdquoinvolves buffing away of the remaining tread in a spenttyre and replacing it with a new tread rubber strip byvulcanization It is carried out only on used tyres casing thathave been inspected and repaired Although it is econom-ically advantageous product quality confidence is a majorchallenge of the process

212 Mechanical or Cryogenic Method Both mechanicaland cryogenic (grinding of waste tyres at temperatures ofminus80∘C to ndash100∘C using liquid nitrogen) recycling of usedtyres involve the milling of tyres to produce ground rubberof different particle sizes The fine grounded rubber canbe used in varieties of application such as an additive inroad asphalting sports and children playground surfacingcarpets and other rubber products However the limitedmarket for the product and a high cost of running the processare a disadvantage

213 Reclaiming Rubber Raw Materials Methods Differentmethods and processes for reclaiming rubber have been

developed The most relevant of them are thermomechan-ical reclaiming [48] microwave reclaiming [49] mechan-ical shearing process [69] reclaiming by biotechnologicalprocess ultrasonic reclaiming [76] reclaiming by renewableresource materials reclaiming by use of different chemicalagents [9] and pyrolysis of waste tyre [77] These meth-ods actually help in transforming used tyres from a threedimensionally interlinked thermoset polymer state to a two-dimensional polymer exhibiting the properties of a virginrubber The high cost of the process quality of products andlack of acceptance of reclaim rubber by industries as a rawmaterial are a setback on the process

Although used tyres can be used as a source of fuel incement kilns by combustion method it is not economicallywise and environmentally friendly [1 4 7]

22 Characteristics and Composition of Used Tyres Tyresare made up of different types of rubber elastomers (natu-ral or synthetic rubber) with varying composition carbonblack stabilizers antioxidants sulphur hydrocarbon oilszinc oxides textile or steel cords [4 6 11 69] and so forthProximate and ultimate analyses of used tyres reported byvarious authors are shown in Tables 1 and 2 The differencein values can be attributed to the manufacturersrsquo formulationwhich is closely guarded and determines to a large extent theweight percent of the various components of tyres

23 Study of Thermal Degradation of Used Tyre Thermo-gravimetry analysis is used to study the general behavior ofthermal degradation of used tyres [13] Both the thermo-gravimetry (TG) and differential thermogravimetry (typicalcurve is shown in Figures 1 and 2) are standard techniquesused in the study of mass change of tyre rubber sample asa function of temperature and time [73 74 78] With theresults data (shown in Table 3) obtained in this study andthose of other authors in the literature it can be understoodthat there is more than one degradation temperature zoneduring tyre rubber pyrolysis This also gives an idea of thecommencement and end point temperature for the differentrubber components in the waste tyre [3 10] For exampleNR (natural rubber) SBR (styrenebutadiene rubber) andBR (butadiene rubber) decompose at a temperature range of375∘C to 500∘C

3 Pyrolysis Process Conditions and Reactors

Pyrolysis mainly involves the thermal degradation of tyrerubber at high temperatures (250ndash900∘C) in an oxygenabsent environment It can be performed under vacuum oratmospheric pressure [23 29] Amongst other methods suchas combustion and gasification used to extract energy frombiomass pyrolysis has received more attention in the areaof research because the process conditions can be optimizedto produce high energy density liquids char and gas Alsothe condensable fraction (biocrude) can be stored and easilytransported to where it can bemost proficiently utilized Tyrepyrolysis can be said to be made up of three stages thatis the release of volatile and moisture at lower temperature

Journal of Catalysts 3

Table 1 Proximate analysis of used tyre rubber

Author Moisture (wt) Ash (wt) Volatile (wt) Fixed carbon (wt) HHV (MJkg)This study 05 160 564 271 312Donatelli et al [31] 08 44 613 335 371Kar [32] 172 1913 5969 1945 2737Chang [33] 131 1021 6232 2626 3324Trongkaew et al [14] 122 873 624 276 357Gonzalez et al [19] 07 80 619 295 362Su and Zhao [34] 08 741 6464 2715 3956Juma et al [9] 172 1401 6161 2266 mdashde Marco et al [35] 588 277 172 mdash mdashWilliams and Bottrill [36] 08 24 665 303 mdash

Table 2 Ultimate analysis of used tyre rubber

Author C (wt) H (wt) N (wt) S (wt) O (wt) Ashes (inorganic)Donatelli et al [31] 852 73 04 23 04 44Kar [32] 6708 612 017 205 2458 mdashChang [33] 7441 694 021 160 502 mdashTrongkaew et al [14] 8010 748 042 154 1050 mdashGonzalez et al [19] 867 810 040 140 130 21Su and Zhao [34] 8184 606 177 164 048 mdashJuma et al [9] 8124 736 049 199 892 mdashde Marco et al [35] 7420 580 03 150 470 135Williams and Bottrill [36] 858 80 04 10 23 24

0

20

40

60

80

100

120

0 100 200 300 400 500 600 700 800

Wei

ght (

)

Temperature (∘C)

Figure 1 Typical TGA curve of used tyre sample

succeeded by the thermal decomposition of natural rubber(NR) and the decomposition of polybutadiene (BR) andpolybutadiene-styrene rubber at higher temperature respec-tively [79 80]

The process conditions that can influence the percentageweight of each fraction of pyrolysis include pressure heatingrate temperature feed particle sizes catalysis flow rate ofinert carrier gas configuration of reactor used [2] and soforth

0

005

01

015

02

025

03

035

04

045

05

0 100 200 300 400 500 600 700 800

Temperature (∘C)

Der

ived

wei

ght (

∘

C)

Figure 2 Typical DTG curve of used tyre sample

31 Pyrolysis Reactors The reactor is a very important partof the pyrolysis process Over the years the innovation andtechnological advancement of pyrolysis has advanced con-siderably Researchers have developed and studied differentreactors and processes to the point where pyrolysis is nowan acceptable technique to the deriving of gaseous liquidsolid fuels and chemicals Table 4 presents the chronologyof pyrolysis process from the 1970s to date Reactors cangreatly influence the pyrolysis performance product qualityand yield [2 46] However each reactors type has its benefits


Table 3 Commencement and end temperatures of pyrolysis of usedtyre

Author

Pyrolysiscommencementtemperature

(∘C)

Pyrolysisend temperature

(∘C)

Heating rate(∘Cmin)

This study 210 520 20Juma et al [9] 250 550 5Conesa et al[38] 250 500 5

Su and Zhao[34] 200 500 10

Senneca et al[39] 200 450 5

and limitations Table 5 shows different types of reactors andtheir heating methods

32 Types of Pyrolysis Pyrolysis process can be performedunder different operating conditions which can be used inclassifying it They are differentiated by residence time of thepyrolysed material in the reactor process temperature feedparticle size heating rate [81ndash83] and so forthThese includethe following

321 Slow Pyrolysis The solid residence time(s) in the reac-tor is 450ndash550 heating rate (∘C) is 01ndash1 and feed particle size(mm) is 5ndash50 with temperature (∘C) of 550ndash950This processenhances char production and is unlikely to be unsuitable forhigh quality bio-oil production Also due to high residencetime secondary reaction is favorable as cracking of primaryproduct occurs which could adversely affect bio-oil yield andquality [84] (Table 6)

322 Fast Pyrolysis Fast pyrolysis involves the rapid heatingof the feed material to a high temperature in the absence ofoxygen with a short residence time of the condensable vaporin the reactor Its operating parameters are solid residencetime between 05 and 10s heating rate of 10ndash200∘C feedparticle size less than 5mm and reaction temperature of550ndash1200∘C The technology has received much popularityin producing liquid fuels and a range of specialty and com-modity chemicals Typically on weight basis fast pyrolysisyields 60ndash75 pyro oil with 15ndash25 compared to otherprocesses it has reasonably low investment costs and highenergy efficiencies particularly on a small scale [85]

323 Flash Pyrolysis This process is characterized by res-idence time of less than 05 s high heating rate of morethan 200∘C particle size of less than 02mm and highreaction temperature of more than 1000∘C However themajor technological challenge of the process is poor thermalstability solids in the oil and production of pyrolytic water[86 87]

324 Catalytic Pyrolysis Catalytic pyrolysis is a pyrolysisprocess that includes the use of a catalyst The catalyst helps

enhance the pyrolysis reaction kinetics by cracking downhigher molecular weight hydrocarbon compounds to lighterhydrocarbon products It has been reported that the useof catalyst in tyre pyrolysis systems can greatly influencethe composition quality and yield of products [6 88]Examples of catalysts used in tyre pyrolysis include Na

2CO3

NaOH MgO CaCO3 aluminium-based catalyst perlite

CaC2 Cu(NO

3)2zeolite-based catalyst and so forth [6 7

89] Operating conditions can determine different productdistribution for different catalysts Pyrolysis catalyst can begrouped based on theirmethod of applicationThe first groupis when the catalyst is added to the feedstock before being fedinto the reactor The second group is when catalyst is addedafter the feed is already heated up in the reactor allowing itto have immediate contact with vapors solid and char Thethird group is when the catalyst is placed in another reactorlocated downstream from the pyrolysis reactor [46 90]

33 Chemical Reaction of the Catalytic Pyrolysis The chemi-cal reaction of catalytic pyrolysis is an endothermic processThree stages involved include dehydration fragmentationand product formation which occur at different temperaturesduring the process It is carried out in an inert environmentin order to avoid combustionThemechanism of the reactionis shown below

[CH2CH=C(CH

3)CH2]119899

polyisoprene

catalyst No O2

997888997888997888997888997888997888997888997888997888997888997888rarr

+ΔHchar gas oil (1)

where ΔH = heat

34 Pyrolysis Products and Their Composition The threeprimary products obtainable from tyre rubber pyrolysis arelisted and discussed below(1) Solid residue or char (34ndash38wt of feedstock) ismade

up of carbon black and other nonvolatile materials such astyre rubber additives like zinc sulphur silica clays and soforth initially present in the tyre This char can be used assolid fuel carbon black or as precursor for activated carbonmanufacturing [22] From the literature elemental analysisshows that the solid residue contains 71 wt of C 133 wtof O 54 wt of Fe 28 wt of S 23 wt of Zn 13 wt ofCa and 03 wt of Al(2) Liquid product (48ndash58wt of feedstock) also known

as pyrolysed tyre oil or biocrude is the most significantproduct of the process It is gotten from the condensationof vapor of a pyrolysis reaction Several publications onthe study of the properties of the pyrolytic oil abound[18 45] It is reported that the calorific value of the oilis 42MJkg percentage content of sulphur ranges between12 and 136 and the oil is a mixture of C6ndashC24 organiccompounds (534ndash748) specified to be paraffins olefinsand aromatic compounds with some nitrogenated (247ndash375) and some oxygenated compounds (229ndash485) [1718 28] Such pyrolytic oil can be used directly as low-sulphur-emission fuels or blend with petroleum productssuch as gasoline feedstock for petroleum refinery and as animportant source for chemicals in chemical industries due tohigh concentration of benzene toluene xylene and limonene


Table 4 Chronology of processes used for pyrolysis of used tyres

Researcher(s) Reactor used Process type YearGotshall [50] nr Destructive distillation 1970Alpert [51] nr Hydroconversion 1972Grannen and Robinson [52] Microwave Microwave pyrolysis 1974Crane and Kay [53] nr Pyrolization 1976Herbold [54] nr Subatmospheric pyrolysis 1978Kaminsky and Sinn [55] Fluidized bed Pyrolysis 1980Ito et al [56] Fluidized bed and incineration fluidized bed chamber Pyrolysis and incineration 1982Engman et al [57] Quartz tube Pyrolysis 1984Bouvier and Gelus [58] Heated cylindrical glass flask Tyre copyrolysis with oil 1986Chou et al [59] Quartz tube Flash pyrolysis 1988Roy et al [60] Batch reactor Vacuum pyrolysis 1990Roy et al [61] Batch reactor Vacuum pyrolysis 1992Pakdel and Roy [62] Continuous feed reactor Vacuum pyrolysis 1994Conesa et al [63] Fluidized bed reactor Pyrolysis 1996Leung and Wang [64] Platinum pan Pyrolysis and combustion 1998Mastral et al [30] Swept fixed bed Pyrolysis and hydropyrolysis 2000Galvagno et al [65] Rotary kiln reactor Pyrolysis 2002Laresgoiti et al [66] Autoclave reactor Pyrolysis 2004Murillo et al [67] Fixed bed reactor Pyrolysis 2006Zhang et al [12] Fixed bed reactor Vacuum pyrolysis 2008Aylon et al [68] Moving bed Pyrolysis 2010Aydin and Ilkilic [15] Fixed bed reactor Pyrolysis 2012Undri et al [4] Microwave oven Microwave assisted pyrolysis 2014This study Plasma reactor Catalytic copyrolysis 2014nr not reported

Table 5 Reactors and their heating methods [23 40ndash42]

Reactor type Heating methodFixed bed Heated wall surfaceBubbling fluidized bed Heated recycle gasCirculating fluidized bed Wall and sand heatingRotating cone Gasification of char to heatAuger Fire tubeFluidized bedquartz SolarPlasma Radio frequencyVacuum Direct contact with hot surfaceAblative Wall heating

[18] Elemental analysis of the tyre pyrolysis oil shows that itcontains 86871 wt of C 1007wt of H 1169wt of N0906wt of S and 1169wt of O(3) Gas fraction (9ndash14wt of feedstock) from the pyrol-

ysis process is mainly composed of H2 CO CH

4 CO2

C2H4 H2S and other light hydrocarbons with SO

2 NO119909

CO and PAHs reported as the main pollutant gases It hasa high heating value of about 37MJm3 an amount of energyenough for the pyrolysis process

It is worthy to note that the composition of the variousfractions is influenced by the pyrolysis conditions used andthe composition of the tyre [2 3 7 10 17]

Table 6 Physical and chemical properties of used tyre oil and dieselfuel [15]

Fuelproperty Diesel fuel Used tyre oilDensity (kgm3) 20∘C 845 945Kinematic viscosity 40∘C in mm2sec 34 38

Flash point 60∘C 50∘CDiesel index 552 419Heat value (MJkg) 46 4334Sulphur amount () 01 0906Cetane number 53 44

4 Pyrolysis Kinetics

Kinetic models for used tyre pyrolysis have been presentedby various authors [91ndash97] Generally the degradation of thetyre rubber is split into two or more steps while thermo-gravimetry data and Arrhenius equation form the basis ofthe models In the kinetic analysis of the data for the tyredecomposition the Arrhenius theory based on first orderreaction is mostly assumed by researchers

119896 = 119860 exp (minus 119864119877119879

) (2)


Table 7 Kinetic parameters obtained by Leung and Wang [64]

Heating rateActivation energy 119864 (KJmol) Preexponential factor 119860 (minminus1) Reaction order 119899Lower

temperatureHigher

temperatureLower

temperatureHigher

temperatureLower

temperatureHigher

temperature10 1645 1361 629 times 10

13

231 times 109 1 1

30 1809 1336 132 times 1014

209 times 109 1 1

45 2034 1070 758 times 1015

334 times 107 1 1

60 2187 991 113 times 1017

102 times 107 1 1

Table 8 Kinetic parameters obtained by Williams and Besler [69]

Heating rate Activation energy 119864 (kJmol) Preexponential factor 119860 (minminus1) Reaction order 119899Sample A Sample B Sample A Sample B Sample A Sample B

5 1427 1208 1450 21 times 108

93 times 107

11 times 108 mdash mdash

20 908 1283 1377 26 times 104

33 times 105


40 704 661 1362 13 times 103

59 times 102


80 664 556 11 times 103


where 119896 is the rate constant 119860 is the preexponential factor(minminus1) 119864 is the activation energy (Jmol) and 119877 and 119879 arethe universal gas constant (8314 Jmolminus1 kminus1) and temperatureof reaction (K) respectively Equation (3) can be used torepresent the rate of tyre decomposition

119889120572

119889119905

= 119896(1 minus 120572)119899

(3)

where 120572 is the fraction of reactant decomposed at time 119905and 119899 is the order of reaction Application of the abovegiven equations for tyre pyrolysis under different conditionsalong with experimental conditions and obtained kineticparameters published in the literature by some authors isgiven below

Leung and Wang [64] Consider the followingModel

119889120572119879

119889119905

=

3

sum

119894=1

119889120572119894

119889119905

=

3

sum

119894=1

119860119894exp(minus119864119894

119877119879

) (1 minus 120572) (4)

where 120572119879(minminus1) is normalized mass loss rate 119860 is preexpo-

nential factor 119864 is activation energy 119877 is ideal gas constant119879 is absolute temperature 119905 is time and index (119894 = 1 2 3) isreaction

Experimental Conditions Temperature 20ndash600∘C particlesize 0355ndash0425mm heating rate 10ndash60∘Cmin and usedmobile gas N

2 The kinetic parameters obtained by Leung

and Wang are given in Table 7

Williams and Besler [69] Consider the followingModel

119889119908

119889119905

= minus119896 (119882 minus119882119891) (5)

where119882 is the weight of sample at time 119905119882119891is the weight

of residue at the end of the reaction and 119896 represents the rateconstant defined by Arrhenius equation

Experimental Conditions Temperature 720∘C sample sizeslt1mm heating rate 5∘Cmin and used mobile gas N

2

Table 8 shows the kinetic parameters obtained

5 Conclusion

Biocrude production from used tyres and natural rubber isa viable means of an alternative renewable energy sourcethat can help caution the fast depletion of crude oil reservesits fast rising cost due to high demand along with itsadverse negative environmental impact This review reportsthe present stage of research in used tyre pyrolysis From theliterature the proximate analyses of tyre rubber show that itis composed of about 286 wt fixed carbon 62wt volatilematerial 85 wt ash and 09 wt moisture Elementalanalyses reveal that tyre rubber has an estimated value of82wt of C 8wt of H 04 wt of N 13 wt of S24 wt of O and 59 wt of ash Both the proximate andultimate analysis value of the used tyres is dependent onthe tyre formulation by the tyre manufacturers Thermo-gravimetry analysis confirms that the pyrolysis of used tyreat atmospheric pressure commences at about 250∘C andcompletes at around a temperature of 550∘C Usually duringtyre pyrolysis there exist different degradation temperaturesThis was also confirmed by the thermogravimetric analysisperformed in our laboratory It was also observed thatpyrolysis products yields and their characteristics are greatlyaffected by the composition of the feed operating conditionsand the specific properties of the system used

Thus results vary from different researchers making itdifficult to compare results Nevertheless the three primaryproducts obtained from used tyres pyrolysis are solid residueor char (around 36wt) liquid fraction or biocrude (around55wt) and gas fraction (around 9wt) with average


higher heating values (HHV) of 28MJ kgminus1 42MJ kgminus1 and36MJNminus1mminus3 respectively

Studies have also shown that the main components of theliquid fractions are aliphatic and aromatic hydrocarbons andhydroxyl compounds while the gases that make up the gasfractions are H

2 CO CH

4 CO2 C2H4 H2S and other light

hydrocarbons with SO2 NO119909 CO and polycyclic aromatic

hydrocarbons (PAHs) reported as the main pollutant gasesThe char contains high fixed-carbon content and inorganicmatter

Although there is a wide difference in results of kineticmodeling of used tyres by different authors in the value ofkinetic parameters obtained generally it is accepted that theprocess is a first order reaction based on Arrhenius theory

Therefore there is the need to investigate the effect ofcopyrolysis of natural rubber (biomass obtained from rubbertree) and used tyre on the pyrolysis product yields in relationto the following

(i) Composition and quantity of gas yield(ii) Enhancing the possibility of more valuable chemical

products from the liquid fraction such as limonenewhich is closely related to polyisoprene (NR) presentin used tyre

(iii) Analyzing the amount of sulphur content in thebiocrude (liquid fraction)

(iv) The quality of char produced in comparison withcommercial carbon black will be the area of ourresearch

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

Financial support from the National Research Foundation(NRF) under the South Africa NRF Focus Area and studentbursaries made available by the University of the Witwater-srand are deeply appreciated

References

[1] M Bianchi G Bortolani M Cavazzoni et al ldquoPreliminarydesign andnumerical analysis of a scrap tyre pyrolysis systemrdquoEnergy Procedia vol 45 pp 111ndash120 2014

[2] J D Martinez A Veses A M Mastral et al ldquoCo-pyrolysis ofbiomass withwaste tyres upgrading of liquid to bio-fuelrdquo FuelProcessing Technology vol 119 pp 263ndash271 2014

[3] S Frigo M Seggiani M Puccini and S Vitolo ldquoLiquid fuelproduction from waste tyre pyrolysis and its utilization in adiesel enginerdquo Fuel vol 116 pp 399ndash408 2014

[4] A Undri L Rosi M Frediani and P Frediani ldquoUpgraded fuelfrom microwave assisted pyrolysis of waste tyrerdquo Fuel vol 115pp 600ndash608 2014

[5] H Hu Y Fang H Liu et al ldquoThe fate of sulfur during rapidpyrolysis of scarp tyresrdquoChemosphere vol 97 pp 102ndash107 2014

[6] P T Williams ldquoPyrolysis of waste tyres a reviewrdquo Wasteman-agement vol 33 pp 1714ndash1728 2013

[7] A Quek and R Balasubramanian ldquoLiquefaction of wastetyres by pyrolysis for oil and chemicalsmdasha reviewrdquo Journal ofAnalytical and Applied Pyrolysis vol 101 pp 1ndash16 2013

[8] S Karthikeyan C Sathiskumar and S R Moorthy ldquoEffectof process parameters on tire pyrolysis a reviewrdquo Journal ofScientific and Industrial Research vol 71 no 5 pp 309ndash3152012

[9] M Juma Z Korenova J Markos J Annus and L JelemenskyldquoPyrolysis and combustion of Scrap tyrerdquo PetroleumampCoal vol48 no 1 pp 15ndash26 2006

[10] J Haydary Z Korenova L Jelemensky and JMarkos ldquoThermaldecomposition of waste polymersrdquo in ThermoPhysics pp 62ndash68 2008

[11] M R Islam M S H K Tushar and H Haniu ldquoProductionof liquid fuels and chemicals from pyrolysis of Bangladeshibicyclerickshaw tire wastesrdquo Journal of Analytical and AppliedPyrolysis vol 82 no 1 pp 96ndash109 2008

[12] X Zhang T Wang L Ma and J Chang ldquoVacuum pyrolysis ofwaste tires with basic additivesrdquoWasteManagement vol 28 no11 pp 2301ndash2310 2008

[13] D Pradhan and R K Singh ldquoThermal pyrolysis of bicycle wastetyre using batch reactorrdquo International Journal of ChemicalEngineering and Application vol 2 no 5 pp 332ndash336 2011

[14] P Trongkaew T Utistham P Reubroycharoen and N Hinchi-ranan ldquoPhotocatalytic desulfurization of waste tire pyrolysisoilrdquo Energies vol 4 no 11 pp 1880ndash1896 2011

[15] H Aydin and C Ilkilic ldquoOptimization of fuel production fromwaste vehicle tyres by pyrolysis and resembling to diesel fuelby various desulfurizationmethodsrdquo Fuel vol 102 pp 605ndash6122012

[16] H Schnecko ldquoRubber recyclingrdquo Macromolecular Symposiavol 135 pp 327ndash343 1998

[17] R AguadoMOlazar D VelezM Arabiourrutia and J BilbaoldquoKinetics of scrap tyre pyrolysis under fast heating conditionsrdquoJournal of Analytical and Applied Pyrolysis vol 73 no 2 pp290ndash298 2005

[18] A M Cunliffe and P T Williams ldquoInfluence of processconditions on the rate of activation of chars derived frompyrolysis of used tiresrdquo Energy and Fuels vol 13 no 1 pp 166ndash175 1999

[19] J F Gonzalez J M Encinar J L Canito and J J RodrıguezldquoPyrolysis of automobile tyre waste Influence of operatingvariables and kinetics studyrdquo Journal of Analytical and AppliedPyrolysis vol 58-59 pp 667ndash683 2001

[20] M Bajus and N Olahova ldquoThermal conversion of scrap tyresrdquoPetroleum amp Coal vol 53 pp 98ndash105 2011

[21] C Roy H Darmstadt B Benallal and C Amen-Chen ldquoChar-acterization of naphtha and carbon black obtained by vacuumpyrolysis of polyisoprene rubberrdquo Fuel Processing Technologyvol 50 no 1 pp 87ndash103 1997

[22] S BoxiongWChunfei L Cai G Binbin andWRui ldquoPyrolysisof waste tyres the influence of USY catalysttyre ratio onproductsrdquo Journal of Analytical and Applied Pyrolysis vol 78no 2 pp 243ndash249 2007

[23] M I Jahirul M G Rasul A A Chowdhury and N AshwathldquoBiofuels production through biomass pyrolysismdasha technicalreviewrdquo Energies vol 5 pp 4952ndash5001 2012

[24] G Harrison and A B Ross ldquoUse of tyre pyrolysis oil for solventaugmentation in two-stage coal liquefactionrdquo Fuel vol 75 no8 pp 1009ndash1013 1996


[25] AHershaft ldquoSolid waste treatment technologyrdquoEnvironmentalScience and Technology vol 6 no 5 pp 412ndash421 1972

[26] S R Fix ldquoMicrowave devulcanizationof rubberrdquo Elastomericsvol 112 no 6 pp 38ndash40 1980

[27] A A Phadke A K Bhattacharya S K Chakraborty and SK De ldquoStudies of vulcanization of reclaimed rubberrdquo RubberChemistry and Technology vol 56 no 4 pp 726ndash736 1983

[28] A I Isayev S P Yushanov and J Chen ldquoUltrasonic devul-canization of rubber vulcanizates I process modelrdquo Journal ofApplied Polymer Science vol 59 no 5 pp 803ndash813 1996

[29] M Beecham Global Market Review of Automotive TyresmdashForecasts to 2014 Pub ID JA1867566 Aroq Limited Broms-grove UK 2008

[30] A MMastral R Murillo M S Callen and T Garcia ldquoOptimi-sation of scrap automotive tyres recycling into valuable liquidfuelsrdquo Resources Conservation and Recycling vol 29 no 4 pp263ndash272 2000

[31] A Donatelli P Iovane and A Molino ldquoHigh energy syngasproduction by waste tyres steam gasification in a rotary kilnpilot plant Experimental and numerical investigationsrdquo Fuelvol 89 no 10 pp 2721ndash2728 2010

[32] Y Kar ldquoCatalytic pyrolysis of car tire waste using expandedperliterdquoWaste Management vol 31 no 8 pp 1772ndash1782 2011

[33] Y M Chang ldquoOn pyrolysis of waste tire degradation rate andproduct yieldsrdquo Resources Conservation and Recycling vol 17no 2 pp 125ndash139 1996

[34] Y Su and B Zhao ldquoPyrolysis of waste tire and its modelrdquo inProceedings of the 4th International Conference on Bioinformat-ics and Biomedical Engineering (iCBBE rsquo10) June 2010

[35] I R de Marco M F Laresgoiti M A Cabrero A Torres MJ Chomon and B Caballero ldquoPyrolysis of scrap tyresrdquo FuelProcessing Technology vol 72 no 1 pp 9ndash22 2001

[36] P T Williams and R P Bottrill ldquoSulfur-polycyclic aromatichydrocarbons in tyre pyrolysis oilrdquo Fuel vol 74 no 5 pp 736ndash742 1995

[37] J Yang P A Tanguy and C Roy ldquoHeat transfer mass transferand kinetics study of the vacuum pyrolysis of a large used tireparticlerdquoChemical Engineering Science vol 50 no 12 pp 1909ndash1922 1995

[38] J A Conesa R Font A Fullana and J A Caballero ldquoKineticmodel for the combustion of tyre wastesrdquo Fuel vol 77 no 13pp 1469ndash1475 1998

[39] O Senneca P Salatino and R Chirone ldquoFast heating-ratethermogravimetric study of the pyrolysis of scrap tyresrdquo Fuelvol 78 no 13 pp 1575ndash1581 1999

[40] L Tang and H Huang ldquoPlasma pyrolysis of biomass forproduction of syngas and carbon adsorbentrdquo Energy and Fuelsvol 19 no 3 pp 1174ndash1178 2005

[41] A Domınguez Y Fernandez B Fidalgo J J Pis and J AMenendez ldquoBio-syngas production with low concentrations ofCO2

and CH4

from microwave-induced pyrolysis of wet anddried sewage sludgerdquo Chemosphere vol 70 no 3 pp 397ndash4032008

[42] X Zhao Z Song H Liu Z Li L Li and C Ma ldquoMicrowavepyrolysis of corn stalk bale a promising method for directutilization of large-sized biomass and syngas productionrdquoJournal of Analytical and Applied Pyrolysis vol 89 no 1 pp 87ndash94 2010

[43] A Quek and R Balasubramanian ldquoMathematical modelingof rubber tire pyrolysisrdquo Journal of Analytical and AppliedPyrolysis vol 95 pp 1ndash13 2012

[44] M Balat M Balat E Kirtay and H Balat ldquoMain routes for thethermo-conversion of biomass into fuels and chemicals Part 1pyrolysis systemsrdquo Energy Conversion andManagement vol 50no 12 pp 3147ndash3157 2009

[45] T Bridgwater Pyrolysis of Biomass IEA Bioenergy Task 34Bioenergy Research Group Aston University BirminghamUK 2007

[46] A V Bridgwater S Czernik and J Piskorz ldquoAn overview of fastpyrolysisrdquo in Progress in Thermochemical Biomass Conversionvol 2 pp 977ndash997 2001

[47] A Demirbas and G Arin ldquoAn overview of biomass pyrolysisrdquoEnergy Sources vol 24 no 5 pp 471ndash482 2002

[48] R Aguado M Olazar B Gaisan R Prieto and J BilbaoldquoKinetic study of polyolefin pyrolysis in a conical spouted bedreactorrdquo Industrial and Engineering Chemistry Research vol 41no 18 pp 4559ndash4566 2002

[49] T Cornelissen J Yperman G Reggers S Schreurs and RCarleer ldquoFlash co-pyrolysis of biomass with polylactic acid Part1 influence on bio-oil yield and heating valuerdquo Fuel vol 87 no7 pp 1031ndash1041 2008

[50] WW Gotshall ldquoReinforcing agent from scrap rubber charrdquo USPatent 3644131 A February 1972

[51] S B Alpert ldquoHydroconversion of waste natural rubber andsynthetic rubbersrdquo US Patent 3704108 November 1972

[52] E A Grannen and L Robinson ldquoMicrowave pyrolysis ofwastesrdquo US Patent 3843457 October 1974

[53] G Crane and E L Kay ldquoPyrolizationrdquo US Patent 3966487 June1976

[54] O Herbold ldquoMethod and apparatus for the pyrolysis of wasteproductsrdquo US Patent 4084521 April 1978

[55] W Kaminsky and H Sinn ldquoPyrolysis of plastic waste and scraptyres using a fluidized processrdquo in Thermal Conversion of SolidWastes and Biomass J L Jones and S B Radding Eds vol 130of American Chemical Society Symposium Series pp 423ndash4391980

[56] K Ito Y Hirayama Y Ishii and N Ando ldquoPyrolyzing appara-tusrdquo US Patent 4324620 April 1982

[57] H Engman H T Mayfield T Mar and W BertschldquoClassification of bacteria by pyrolysis-capillary column gaschromatography-mass spectrometry and pattern recognitionrdquoJournal of Analytical and Applied Pyrolysis vol 6 no 2 pp137ndash156 1984

[58] JM Bouvier andMGelus ldquoPyrolysis of rubber wastes in heavyoils and use of the productsrdquo Resources and Conservation vol12 no 2 pp 77ndash93 1986

[59] M I M Chou M A Lake and R A Griffin ldquoFlash pyrolysisof coal coal maceral and coal-derived pyrite with on-line char-acterization of volatile sulfur compoundsrdquo Journal of Analyticaland Applied Pyrolysis vol 13 no 3 pp 199ndash207 1988

[60] C Roy B Labrecque and B de Caumia ldquoRecycling of scraptires to oil and carbon black by vacuum pyrolysisrdquo ResourcesConservation and Recycling vol 4 no 3 pp 203ndash213 1990

[61] V Roy B de Caumia and C Roy ldquoDevelopment of a gas-cleaning system for a scrap-tire vacuum-pyrolysis plantrdquo GasSeparation and Purification vol 6 no 2 pp 83ndash87 1992

[62] H Pakdel and C Roy ldquoSimultaneous gas chromatographicmdashFourier transform infrared spectroscopicmdashmass spectrometricanalysis of synthetic fuel derived from used tire vacuumpyrolysis oil naphtha fractionrdquo Journal of Chromatography Avol 683 no 1 pp 203ndash214 1994


[63] J A Conesa R Font and A Marcilla ldquoGas from the pyrolysisof scrap tires in a fluidized bed reactorrdquo Energy and Fuels vol10 no 1 pp 134ndash140 1996

[64] D Y C Leung and C L Wang ldquoKinetic study of scrap tyrepyrolysis and combustionrdquo Journal of Analytical and AppliedPyrolysis vol 45 no 2 pp 153ndash169 1998

[65] S Galvagno S Casu T Casabianca A Calabrese and GCornacchia ldquoPyrolysis process for the treatment of scrap tyrespreliminary experimental resultsrdquo Waste Management vol 22no 8 pp 917ndash923 2002

[66] M F Laresgoiti B M Caballero I de Marco A Torres MA Cabrero and M J Chomon ldquoCharacterization of the liquidproducts obtained in tyre pyrolysisrdquo Journal of Analytical andApplied Pyrolysis vol 71 no 2 pp 917ndash934 2004

[67] R Murillo E Aylon M V Navarro M S Callen A Arandaand A M Mastral ldquoThe application of thermal processes tovalorise waste tyrerdquo Fuel Processing Technology vol 87 no 2pp 143ndash147 2006

[68] E Aylon A Fernandez-Colino R Murillo M V NavarroT Garcıa and A M Mastral ldquoValorisation of waste tyre bypyrolysis in a moving bed reactorrdquoWaste Management vol 30no 7 pp 1220ndash1224 2010

[69] P T Williams and S Besler ldquoPyrolysis-thermogravimetricanalysis of tyres and tyre componentsrdquo Fuel vol 74 no 9 pp1277ndash1283 1995

[70] J Bi X Guo M Liu and X Wang ldquoHigh effective dehydrationof bio-ethanol into ethylene over nanoscale HZSM-5 zeolitecatalystsrdquo Catalysis Today vol 149 no 1-2 pp 143ndash147 2010

[71] J A Conesa and AMarcilla ldquoKinetic study of the thermogravi-metric behavior of different rubbersrdquo Journal of Analytical andApplied Pyrolysis vol 37 no 1 pp 95ndash110 1996

[72] L M Mahlangu Waste tyre management problems in SouthAfrica and the possible Opportunities that can be created throughthe recycling therefore [MS thesis] 2009

[73] J H Chen K S Chen and L Y Tong ldquoOn the pyrolysis kineticsof scrap automotive tiresrdquo Journal of Hazardous Materials vol84 no 1 pp 43ndash55 2001

[74] M Liompart L Sanchez-Prado J P Lamas C Garcia-Jares ERoca and T Dagnac ldquoHazardous organic chemicals in rubberrecycled tyre playgrounds and paversrdquoChemosphere vol 90 pp423ndash431 2013

[75] J P Lin C Y Chang andCHWu ldquoPyrolysis kinetics of rubbermixturesrdquo Journal of Hazardous Materials vol 58 no 1ndash3 pp227ndash236 1998

[76] H Cui J Yang and Z Liu ldquoPyrolysis of tires and tirecomponents byTGDTAanalyzerrdquo Journal of Chemical Industryand Engineering vol 50 no 6 pp 826ndash833 1999

[77] J G Brammer and A V Bridgwater ldquoDrying technologiesfor an integrated gasification bio-energy plantrdquo Renewable ampSustainable Energy Reviews vol 3 no 4 pp 243ndash289 1999

[78] M Olazar G Lopez M Arabiourrutia G Elordi R Aguadoand J Bilbao ldquoKinetic modelling of tyre pyrolysis in a conicalspouted bed reactorrdquo Journal of Analytical andApplied Pyrolysisvol 81 no 1 pp 127ndash132 2008

[79] California Integrated waste management Board (CIWMB)ldquoEffects of waste tires waste tire facilities andwaste tire projectson the environmentrdquo CIWMB Report 432-96-029 1996

[80] SUcar S Karagoz A ROzkan and J Yanik ldquoEvaluation of twodifferent scrap tires as hydrocarbon source by pyrolysisrdquo Fuelvol 84 no 14-15 pp 1884ndash1892 2005

[81] E L K Mui W H Cheung and G McKay ldquoTyre charpreparation from waste tyre rubber for dye removal fromeffluentsrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp151ndash158 2010

[82] ODoganM B Elik andB Ozdalyan ldquoThe effect of tire derivedfueldiesel fuel blends utilization on diesel engine performanceand emissionsrdquo Fuel vol 95 pp 340ndash346 2012

[83] S Murugan M C Ramaswamy and G Nagarajan ldquoThe use oftyre pyrolysis oil in diesel enginesrdquoWaste Management vol 28no 12 pp 2743ndash2749 2008

[84] S Ucar S Karagoz J Yanik M Saglam and M Yuksel ldquoCopy-rolysis of scrap tires with waste lubricant oilrdquo Fuel ProcessingTechnology vol 87 no 1 pp 53ndash58 2005

[85] A M Fernandez C Barriocanal and R Alvarez ldquoPyrolysis ofa waste from the grinding of scrap tyresrdquo Journal of HazardousMaterials vol 203-204 pp 236ndash243 2012

[86] KUnapumnuk TCKeenerM Lu andF Liang ldquoInvestigationinto the removal of sulfur from tire derived fuel by pyrolysisrdquoFuel vol 87 no 6 pp 951ndash956 2008

[87] S Murugan M C Ramaswamy and G Nagarajan ldquoPerfor-mance emission and combustion studies of a DI diesel engineusing distilled Tyre pyrolysis oil-diesel blendsrdquo Fuel ProcessingTechnology vol 89 no 2 pp 152ndash159 2008

[88] S MuruganM C Ramaswamy andG Nagarajan ldquoAssessmentof pyrolysis oil as an energy source for diesel enginesrdquo FuelProcessing Technology vol 90 no 1 pp 67ndash74 2009

[89] D Bunthid P Prasassarakich and N HinchirananldquoOxidative desulfurization of tire pyrolysis naphtha informic acidH

2

O2

pyrolysis char systemrdquo Fuel vol 89 no 9pp 2617ndash2622 2010

[90] M Miranda F Pinto I Gulyurtlu I Cabrita C A Nogueiraand A Matos ldquoResponse surface methodology optimizationapplied to rubber tyre and plastic wastes thermal conversionrdquoFuel vol 89 no 9 pp 2217ndash2229 2010


[92] A Napoli Y Soudais D Lecomte and S Castillo ldquoScraptyre pyrolysis are the effluents valuable productsrdquo Journal ofAnalytical and Applied Pyrolysis vol 40-41 pp 373ndash382 1997

[93] C Ilkilic and H Aydin ldquoFuel production from waste vehicletires by catalytic pyrolysis and its application in a diesel enginerdquoFuel Processing Technology vol 92 no 5 pp 1129ndash1135 2011

[94] S Hariharan S Murugan and G Nagarajan ldquoEffect of diethylether on tyre pyrolysis oil fueled diesel enginesrdquo Fuel vol 104pp 109ndash115 2013

[95] P Behera and S Murughan ldquoCombustion performance andemission parameters of used transformer oil and its dieselblends in a DI diesel enginerdquo Fuel vol 104 pp 147ndash154 2013

[96] A V Bridgwater ldquoReview of fast pyrolysis of biomass andproduct upgradingrdquo Biomass and Bioenergy vol 38 pp 68ndash942012

[97] Y Yang J G Brammer M Ouadi et al ldquoCharacterisation ofwaste derived intermediate pyrolysis oils for use as diesel enginefuelsrdquo Fuel vol 103 pp 247ndash257 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


used as petroleum refinery feedstock or a source of chemicalsfor wide industrial applications Gaseous fraction can be usedas fuel or as a source of energy for the pyrolysis process[22 28 29 45ndash49]

This paper presents a literature review of the pyrolysisprocess with a focus on the characteristics of used tyresmaterials and methods of recycling types and principlesof pyrolysis properties of the pyrolysis products effects ofprocess parameters and kinetic models applied to pyrolysis

2 Used Tyres

Used tyres also referred to as waste tyres can be definedas tyres that have expired as a result of exceeding theirproduction life span or are no longer safe for usage dueto defects such as degradation of its physical composi-tionstructure from use and cannot be retreaded It is one ofthe most challenging hazardous solid wastes facing modernsociety particularly in developing countries [3 10 11] It isestimated that the EU Japan and USA generate 6 times 106 tonsof waste tyres annually [6 22 23 46 64] According to areport 160000 tons of waste tyres are generated in SouthAfrica annually and up to 28 million used tyres are dumpedunlawfully or burnt [70] This figure is projected to increaseby 93 million yearly [70] The nonbiodegradable nature ofthis polymer material makes its disposal difficult Disposalby massive stockpiling and landfilling is one of the commonways of handling waste tyre but this requires a large space asthe volume of tyres cannot be compactedThese also poise thedanger of the possibility of fire outbreak with the emission ofharmful gases [1 7 19 21 22 64 71ndash75]

21 Methods of Recycling of Used Tyres The various methodsin which used tyres are recycled are discussed below

211 RetreadingMethod Retread also referred to as ldquoremoldrdquoinvolves buffing away of the remaining tread in a spenttyre and replacing it with a new tread rubber strip byvulcanization It is carried out only on used tyres casing thathave been inspected and repaired Although it is econom-ically advantageous product quality confidence is a majorchallenge of the process

212 Mechanical or Cryogenic Method Both mechanicaland cryogenic (grinding of waste tyres at temperatures ofminus80∘C to ndash100∘C using liquid nitrogen) recycling of usedtyres involve the milling of tyres to produce ground rubberof different particle sizes The fine grounded rubber canbe used in varieties of application such as an additive inroad asphalting sports and children playground surfacingcarpets and other rubber products However the limitedmarket for the product and a high cost of running the processare a disadvantage

213 Reclaiming Rubber Raw Materials Methods Differentmethods and processes for reclaiming rubber have been

developed The most relevant of them are thermomechan-ical reclaiming [48] microwave reclaiming [49] mechan-ical shearing process [69] reclaiming by biotechnologicalprocess ultrasonic reclaiming [76] reclaiming by renewableresource materials reclaiming by use of different chemicalagents [9] and pyrolysis of waste tyre [77] These meth-ods actually help in transforming used tyres from a threedimensionally interlinked thermoset polymer state to a two-dimensional polymer exhibiting the properties of a virginrubber The high cost of the process quality of products andlack of acceptance of reclaim rubber by industries as a rawmaterial are a setback on the process

Although used tyres can be used as a source of fuel incement kilns by combustion method it is not economicallywise and environmentally friendly [1 4 7]

22 Characteristics and Composition of Used Tyres Tyresare made up of different types of rubber elastomers (natu-ral or synthetic rubber) with varying composition carbonblack stabilizers antioxidants sulphur hydrocarbon oilszinc oxides textile or steel cords [4 6 11 69] and so forthProximate and ultimate analyses of used tyres reported byvarious authors are shown in Tables 1 and 2 The differencein values can be attributed to the manufacturersrsquo formulationwhich is closely guarded and determines to a large extent theweight percent of the various components of tyres

23 Study of Thermal Degradation of Used Tyre Thermo-gravimetry analysis is used to study the general behavior ofthermal degradation of used tyres [13] Both the thermo-gravimetry (TG) and differential thermogravimetry (typicalcurve is shown in Figures 1 and 2) are standard techniquesused in the study of mass change of tyre rubber sample asa function of temperature and time [73 74 78] With theresults data (shown in Table 3) obtained in this study andthose of other authors in the literature it can be understoodthat there is more than one degradation temperature zoneduring tyre rubber pyrolysis This also gives an idea of thecommencement and end point temperature for the differentrubber components in the waste tyre [3 10] For exampleNR (natural rubber) SBR (styrenebutadiene rubber) andBR (butadiene rubber) decompose at a temperature range of375∘C to 500∘C

3 Pyrolysis Process Conditions and Reactors

Pyrolysis mainly involves the thermal degradation of tyrerubber at high temperatures (250ndash900∘C) in an oxygenabsent environment It can be performed under vacuum oratmospheric pressure [23 29] Amongst other methods suchas combustion and gasification used to extract energy frombiomass pyrolysis has received more attention in the areaof research because the process conditions can be optimizedto produce high energy density liquids char and gas Alsothe condensable fraction (biocrude) can be stored and easilytransported to where it can bemost proficiently utilized Tyrepyrolysis can be said to be made up of three stages thatis the release of volatile and moisture at lower temperature






0

20

40

60

80

100

120

0 100 200 300 400 500 600 700 800

Wei

ght (

)

Temperature (∘C)




0

005

01

015

02

025

03

035

04

045

05

0 100 200 300 400 500 600 700 800

Temperature (∘C)

Der

ived

wei

ght (

∘

C)





Author


(∘C)


(∘C)



Su and Zhao[34] 200 500 10









2CO3


CaC2 Cu(NO




[CH2CH=C(CH

3)CH2]119899

polyisoprene

catalyst No O2

997888997888997888997888997888997888997888997888997888997888997888rarr


where ΔH = heat











4 CO2


2 NO119909








119896 = 119860 exp (minus 119864119877119879

) (2)




temperatureHigher

temperatureLower

temperatureHigher

temperatureLower

temperatureHigher


13

231 times 109 1 1

30 1809 1336 132 times 1014

209 times 109 1 1

45 2034 1070 758 times 1015

334 times 107 1 1

60 2187 991 113 times 1017

102 times 107 1 1



5 1427 1208 1450 21 times 108

93 times 107


20 908 1283 1377 26 times 104

33 times 105


40 704 661 1362 13 times 103

59 times 102


80 664 556 11 times 103



119889120572

119889119905

= 119896(1 minus 120572)119899

(3)



119889120572119879

119889119905

=

3

sum

119894=1

119889120572119894

119889119905

=

3

sum

119894=1

119860119894exp(minus119864119894

119877119879

) (1 minus 120572) (4)







119889119908

119889119905

= minus119896 (119882 minus119882119891) (5)




2


5 Conclusion






2 CO CH












Acknowledgments


References











































and CH4



















































2

O2



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of






0

20

40

60

80

100

120

0 100 200 300 400 500 600 700 800

Wei

ght (

)

Temperature (∘C)




0

005

01

015

02

025

03

035

04

045

05

0 100 200 300 400 500 600 700 800

Temperature (∘C)

Der

ived

wei

ght (

∘

C)





Author


(∘C)


(∘C)



Su and Zhao[34] 200 500 10









2CO3


CaC2 Cu(NO




[CH2CH=C(CH

3)CH2]119899

polyisoprene

catalyst No O2

997888997888997888997888997888997888997888997888997888997888997888rarr


where ΔH = heat











4 CO2


2 NO119909








119896 = 119860 exp (minus 119864119877119879

) (2)




temperatureHigher

temperatureLower

temperatureHigher

temperatureLower

temperatureHigher


13

231 times 109 1 1

30 1809 1336 132 times 1014

209 times 109 1 1

45 2034 1070 758 times 1015

334 times 107 1 1

60 2187 991 113 times 1017

102 times 107 1 1



5 1427 1208 1450 21 times 108

93 times 107


20 908 1283 1377 26 times 104

33 times 105


40 704 661 1362 13 times 103

59 times 102


80 664 556 11 times 103



119889120572

119889119905

= 119896(1 minus 120572)119899

(3)



119889120572119879

119889119905

=

3

sum

119894=1

119889120572119894

119889119905

=

3

sum

119894=1

119860119894exp(minus119864119894

119877119879

) (1 minus 120572) (4)







119889119908

119889119905

= minus119896 (119882 minus119882119891) (5)




2


5 Conclusion






2 CO CH












Acknowledgments


References











































and CH4



















































2

O2



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



Author


(∘C)


(∘C)



Su and Zhao[34] 200 500 10









2CO3


CaC2 Cu(NO




[CH2CH=C(CH

3)CH2]119899

polyisoprene

catalyst No O2

997888997888997888997888997888997888997888997888997888997888997888rarr


where ΔH = heat











4 CO2


2 NO119909








119896 = 119860 exp (minus 119864119877119879

) (2)




temperatureHigher

temperatureLower

temperatureHigher

temperatureLower

temperatureHigher


13

231 times 109 1 1

30 1809 1336 132 times 1014

209 times 109 1 1

45 2034 1070 758 times 1015

334 times 107 1 1

60 2187 991 113 times 1017

102 times 107 1 1



5 1427 1208 1450 21 times 108

93 times 107


20 908 1283 1377 26 times 104

33 times 105


40 704 661 1362 13 times 103

59 times 102


80 664 556 11 times 103



119889120572

119889119905

= 119896(1 minus 120572)119899

(3)



119889120572119879

119889119905

=

3

sum

119894=1

119889120572119894

119889119905

=

3

sum

119894=1

119860119894exp(minus119864119894

119877119879

) (1 minus 120572) (4)







119889119908

119889119905

= minus119896 (119882 minus119882119891) (5)




2


5 Conclusion






2 CO CH












Acknowledgments


References











































and CH4



















































2

O2



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of








4 CO2


2 NO119909








119896 = 119860 exp (minus 119864119877119879

) (2)




temperatureHigher

temperatureLower

temperatureHigher

temperatureLower

temperatureHigher


13

231 times 109 1 1

30 1809 1336 132 times 1014

209 times 109 1 1

45 2034 1070 758 times 1015

334 times 107 1 1

60 2187 991 113 times 1017

102 times 107 1 1



5 1427 1208 1450 21 times 108

93 times 107


20 908 1283 1377 26 times 104

33 times 105


40 704 661 1362 13 times 103

59 times 102


80 664 556 11 times 103



119889120572

119889119905

= 119896(1 minus 120572)119899

(3)



119889120572119879

119889119905

=

3

sum

119894=1

119889120572119894

119889119905

=

3

sum

119894=1

119860119894exp(minus119864119894

119877119879

) (1 minus 120572) (4)







119889119908

119889119905

= minus119896 (119882 minus119882119891) (5)




2


5 Conclusion






2 CO CH












Acknowledgments


References











































and CH4



















































2

O2



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




temperatureHigher

temperatureLower

temperatureHigher

temperatureLower

temperatureHigher


13

231 times 109 1 1

30 1809 1336 132 times 1014

209 times 109 1 1

45 2034 1070 758 times 1015

334 times 107 1 1

60 2187 991 113 times 1017

102 times 107 1 1



5 1427 1208 1450 21 times 108

93 times 107


20 908 1283 1377 26 times 104

33 times 105


40 704 661 1362 13 times 103

59 times 102


80 664 556 11 times 103



119889120572

119889119905

= 119896(1 minus 120572)119899

(3)



119889120572119879

119889119905

=

3

sum

119894=1

119889120572119894

119889119905

=

3

sum

119894=1

119860119894exp(minus119864119894

119877119879

) (1 minus 120572) (4)







119889119908

119889119905

= minus119896 (119882 minus119882119891) (5)




2


5 Conclusion






2 CO CH












Acknowledgments


References











































and CH4



















































2

O2



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




2 CO CH












Acknowledgments


References











































and CH4



















































2

O2



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



















and CH4



















































2

O2



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





























2

O2



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

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Review Article Biocrude Production through Pyrolysis of ...downloads.hindawi.com/archive/2014/386371.pdf · transportedtowhereitcanbemostpro cientlyutilized.Tyre pyrolysis can be