Application of coal conversion technology to tire processing

Tire recycling has been carried out using technology most commonly developed for coal conversion processes trying to take advantage of well-known reactors. Two different batch reaction systems (tubing bomb reactors and magnetically stirred autoclave) and a continuous reactor (swept fixed bed reactor) were tested. In addition, the influence of hydrogen pressure (ranging from 1 to 10 MPa) was assessed together with the influence of an inert or a hydrogenating atmosphere. Independently of the reactor used (tubing bomb reactors or magnetically stirred autoclave), the initial hydrogen pressure and the atmosphere, the 100% of the organic matter conversion was obtained in all the runs when batch reactors were used. When the semicontinuous reactor was used, slightly lower conversions were obtained, probably due to the deposition of products on the surface of the solid products. In all the experiments, conversion products were always oils and gases (comprised mainly of light hydrocarbons) plus a rich in carbon black solid residue. It was observed that the distribution between oils and gases was a function of the reactor type and in some cases a function of the hydrogen pressure. Oils were characterised by thin layer chromatography coupled to a flame ionisation detector (TLC-FID) and by simulated distillation. Different results in oils composition were obtained as a function of the reactor type and hydrogen pressure. (C) 1999 Elsevier Science B.V. All rights reserved.