Feedstock recycling of synthetic and natural rubber by pyrolysis in a fluidized bed

An indirect heated fluidized bed process has been used for the pyrolysis of synthetic and natural rubber. The throughput capacity for the continuously running plant was 500–3000 g/h. The results are compared to a pilot plant for the pyrolysis of whole tires. Beside the recovery of oil and carbon black it was another goal of the study to investigate how much monomer material such as isoprene and isobutene can be obtained from synthetic and natural rubber. The pyrolysis parameters were optimized such as pyrolysis temperature, kind of fluidizing gas, and residence time of the gas in the pyrolysis reactor. Main products of the pyrolysis of tires are an aromatic-rich oil and carbon black, which can be reused. While it was possible to obtain only 2–4 wt% of isobutene, the isoprene content reached 22 wt% from natural rubber.