Pyrolysis of synthetic tire rubber in a fluidised-bed reactor to yield 1,3-butadiene, styrene and carbon black

The pyrolysis of scrap tires in an indirectly heated fluidised-bed according to the 'Hamburg Pyrolysis Process' is well-known for yielding basic chemicals as benzene, toluene and xylenes as well as carbon black with reinforcing properties at reaction temperatures of 700 degreesC and higher. Object of this study was to investigate if pyrolysis could also be carried out after this process at lower temperatures in order to reduce the energy need. Synthetic tire rubber was pyrolysed in a fluidised-bed reactor on laboratory scale (1 kg h(-1)). The distribution of the pyrolysis products was investigated in three experiments in the temperature range between 500 and 600 degreesC. In a fourth experiment the influence of steam as fluidising gas was studied. Complete mass balances of all product fractions were obtained. The main products were carbon black, styrene and 1,3-butadiene. The yield of gas, light oil fraction and char increased with the pyrolysis temperature, whereas the yield of the tar fraction decreased. The use of steam as fluidising medium at 500 degreesC did not affect the quality of the obtained carbon black. (C) 2001 Elsevier Science B.V. All rights reserved.