Characterization Of Pyrolysis Chars Prepared From Waste Tire Tread And Side Wall

The commercial operation of pyrolysis of waste tires resulted in poor economic performance due to the low quality of pyrolytic carbon.The properties of the recovered pyrolytic carbon from different components of the waste tire should be different because of the change in composition of each component.Therefore,the main objective and innovative idea address in this study is to produce pyrolytic carbon from treads and walls of waste tire separately which has not been studied before.As the char produced from different parts of tires should have distinct characterization,therefore this study aims to explore the potential industrial application and economical utilization of the produced char from each component,thus providing a new approach for waste tire pyrolysis for economical industrial application of its products.In this study,experiments were carried out in a laboratory scale fixed bed furnace in order to explore the characteristics of char produced from the waste tire pyrolysis of tread and side walls at different pyrolysis temperatures(400~oC,450~oC,500~oC,550~oC,600~oC),where used Michelin waste tire for cars as feed.Furthermore,in order to explore the potential industrial application,the experiments were also carried out on a pilot scale fixed bed reactor with a capacity of 60 kg per batch.Pilot scale experiments were carried out at temperature450~oC and 2 hours residence time and three different kinds of feed from Hankook waste tire for cars were used(i.e.tread,side wall and the mixed sample of waste tire).After the experiments the produced products were collected so as to calculate yield,and also characteristics of pyrolytic carbon were analyzed.In the end three different kinds of commercially available carbon blacks(i.e.filler carbon,semi-reinforced carbon black and color carbon black)were systematically characterized and compared,in order to explore the potential substitute applications of each pyrolytic carbon.The results of lab-scale and pilot-scale were found similar,the chars from tread and side wall both have some similarity(taking pilot-scale pyrolytic carbon as an example):Both are mesoporous materials with mesoporous ratio more than 90%.Each contain Zn,Si,Al,Ca,Fe,Na inorganic elements,and are dominated by Zn elements,both contain the same type of surface functional groups.At the same time,the two have a certain difference(with the pilot-scale pyrolysis carbon as an example):compared with pyrolysis carbon from tread,the pyrolysis carbon acquired from side wall has higher carbon content(89.55%vs 84.53%),lower ash content(7.28%vs 14.84%),high specific surface area(93.58 m2/g vs 27.05 m2/g),high surface activity(main functional group-OH vs C-O-C)and a narrow range of pore size distribution.According to the comparison of carbon content,ash content,BET analysis,FTIR and XRD analysis results of the characteristics of pyrolytic carbon derived from waste tire tread and sidewall,it can be concluded that the pyrolytic carbon of the waste tire tread have great difference in nature,as compared with the pyrolytic carbon derived from the waste tire side wall,it has higher carbon content,lower ash contents,higher specific surface area and higher surface activity characteristics.Based on the characteristics of pyrolytic carbon and commercial carbon black,it can be concluded that the pyrolytic carbon of the waste tread derived from the pilot test can be used as commercial N660,and the pyrolysis carbon black in the sidewall should be activated if used for carbon black because of limitation of its specific surface area.The char acquired from tread in the laboratory test is considered as filler by the high ash content,the pyrolytic carbon derived from the sidewall has the potential to utilize as reinforce carbon black.Therefore,the fine classification of raw materials can increase the stability of the pyrolytic carbon properties of the waste tires,and according to the distinct characteristics of the pyrolysis carbon,we can choose different reasonable recycling ways,so as to reduce the cost of the subsequent treatment.