Insight into the joint valorization of CO2 and waste plastics by pyrolysis and in line dry reforming for syngas production

Abstract

This paper assesses the potential of plastics valorization by pyrolysis and in line catalytic dry reforming for syngas production. Previous studies showed the suitability of a continuous process made up of a conical spouted bed reactor for fast pyrolysis and a fluidized bed reactor for catalytic steam reforming. In order to step further in the application of this technology under dry reforming conditions, equilibrium simulation was approached to analyze process performance, as the development and optimization of this technology for the production of high-quality syngas requires understanding in detail the complex influence of process parameters. Thus, this study deals with the influence of main process parameters, namely, temperature, CO₂/C ratio and the type of plastic, on the process performance. Furthermore, the role played by steam co-feeding in the dry reforming in order to adjust syngas H₂/CO ratio was evaluated by varying the steam/carbon ratio. The obtained results clearly show that a strict control of process conditions is required to ensure high conversion to syngas and avoid undesired reactions, such as reverse WGS. Among the plastics studied, polyolefins are those of highest potential for syngas production, but polystyrene allows producing a high quality syngas through a combined reforming strategy.