Hydrogen production from rubber tyre through thermochemical processes

Rubber from old tyre is a non-biodegradable residue that causes remarkable environmental problems. In fact, most of the waste tyres generated in the EU are dumped in land fields. However, the incoming legislation is very restrictive and by the year 2006 these practices will be forbidden. Rubber tyre is a product obtained mainly from petroleum and it is roughly composed of polymeric material (polybutadiene, styrene-butadiene rubber and natural rubber), carbon black and some inorganic materials (mainly SiO2 and ZnO). Because of this composition, rubber tyre is a product with both high calorific value and high H/C ratio. However the direct combustion process, although it is cheap and easy, is not an appropriate solution due to the important organic emissions reported. Therefore, the use of other thermochemical processes seems to be a feasible approximation to sort out the associated environmental problems with rubber tyre recycling. In this paper the possibility of producing hydrogen from rubber tyre is assessed. First, a previous thermolysis step is proposed to achieve the rubber tyre devolatilisation. By thermolysis, a gas stream is produced that could be used for hydrogen production.