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

Abstract

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 chain-scission 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.