Multiple benefits of polypropylene plasma gasification to consolidate plastic treatment, CO₂ utilization, and renewable electricity storage

Polypropylene and carbon dioxide were converted into syngas and solid nanostructured carbon particles. A direct current steam plasma torch provided the high enthalpy for the endothermic process. If the plasma process is powered by renewable electricity, it can be an environmentally viable method for waste treatment, energy conversion, and CO₂ utilization. The temperature measured on the walls of the reactor was in the range of 1,150 and 1,350 °C, but the temperature of the heat source (steam plasma) was around 10,000 °C. The gasifying agent (carbon dioxide) was injected into the reactor at two gasification ratios (sub-stoichiometric or above-stoichiometric). The carbon dioxide conversion rate achieved was 98.5 %. The characterization of the produced nanostructured solid carbon (by HRTEM, SEM, XPS, XRD, EDS and GC–MS) confirmed the complete conversion of polypropylene, as no remnants were found in the product. The nanostructured carbon produced can be used for polymer and tire reinforcement and create additional value for the process as a side product of synthesis gas generation from plastic waste and CO₂.