Three-dimensional computational fluid-dynamic simulation of polypropylene steam gasification

Among the recycling techniques, gasification allows to obtain a hydrogen-rich gas from polypropylene (PP), a widely used thermoplastic material. In this work, devolatilization and steam gasification tests of PP were conducted in fluidized bed reactors. The results show a gas yield of 1.3 and 3.0 Nm3/kgPP, and a tar content of 117.3 and 20.9 g/Nm3 from devolatilization and gasification, respectively. Experimental results provide an overall overview of this process, able to produce a syngas with an H2-content of 50 vol%dry. Experimental data coupled with kinetic analysis were used to develop a computational fluid dynamic model (CFD) capable of describing both thermal degradation and subsequent gasification reactions. Although some discrepancies on water conversion and H2/CO ratio probably related to the influence of steam in radical chainscission the model allows to describe gas production and hydrocarbons evolution providing important support for modeling and sizing of fluidized bed reactors on an industrial scale.