DEVELOPMENT OF A CONTINUOUS ROTATING CONE REACTOR PILOT-PLANT FOR THEPYROLYSIS OF POLYETHENE AND POLYPROPENE

A pilot plant for the high-temperature pyrolysis of polymers to recycl e plastic waste to valuable products was constructed based on the rota ting cone reactor (RCR) technology. The RCR used in this pilot plant, termed the continuous RCR ([C]RCR) was an improved version of the benc h-scale RCR ([B]RCR) previously used for the pyrolysis of biomass, Pol yethene (PE), and Polypropene (PP). The improvements resulted in a hig her total alkene yield in the [C]RCR compared to the [B]RCR for the py rolysis of PE and PP. While the total alkene product yield amounts onl y to 51 wt % in the [B]RCR for PE, in the [C]RCR it could be increased to 66 wt %, which is comparable to the 65 wt % total alkene yield obt ained in a bubbling fluidized bed (BFB) of similar scale. Together wit h the fact that almost no utilities are required for operation of a RC R, the product spectra obtained make this technology a good alternativ e to the reactor technologies presently applied in pyrolysis processes . Optimum total alkene yields are obtained at temperatures around 1023 K, as intermediate waxlike compounds are not converted at lower tempe ratures whereas too much aromatics and methane are formed at higher te mperatures. The reactor and BFB temperature in the pilot plant have th e largest impact on the product spectrum obtained, while the sand and polymer mass flow rates have a very limited effect. For PP pyrolysis t he effect of the aforementioned parameters is more pronounced, because this polymer is more sensitive to thermal degradation.