Pyrolysis of Scrap Rubber

On the whole, it could be said that the purpose of the operation was to consider the pyrolysis process as a source of chemicals either in liquid or gaseous state, as well as of char able to give carbon black [42-49]. 

A classical study was made to determine the domain of temperature for the pyrolysis to start, by using the loss in weight of the rubber scrap as a function of 

The carbon blacks obtained by pyrolysis of special fractions of petroleum show typical properties, which are needed for reinforcing the rubber in tires, as shown in Reference [56] on this particular subject. 

Recently, the carbon blacks, obtained by the pyrolysis of discarded tires and proposed for several years, have been evaluated. This process, run either at normal or reduced pressure, yields gas, oils, and chars. It was found that the carbon blacks obtained from the chars by most of the processes in operation worldwide have similar physico-chemical characteristics. Moreover, from the results published in a recent international conference devoted to this subject, it has beeu found that, due to their properties, these carbon blacks could be used to reinforce rubber, either alone or as additive to normal carbon blacks obtained as usual from pyrolysis of petroleum [57]. 

Concluding this way of reusing scrap rubber from tires, the observations made in Section 8.2.4 still stand this process seems to be economically attractive only as long as there is a petroleum shortage. 

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Pyrolysis of scrap rubber may be conducted under significantly varied conditions of time, temperature, and pressure. It may be effected under reductive or oxidative conditions which in turn could be catalytic or noncatalytic. In considering scale-up, engineering alternatives are more important than in most chemical processes. For example, product yield and quality would be expected to be different in batch operation from that in continuous operation. 

Pyrolysis of scrap rubber gives oil and char, from which carbon black can be obtained. The process has been tested on a small scale, more often on a laboratory scale, and sometimes on a large scale, and seems promising [57], in spite of the high quality required for the carbon black used to reinforce rubber, especially in tires [56]. 

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