NiO/Dolomite Catalyzed Steam/O2 Gasification of Different Plastics and Their Mixtures

The catalytic gasification of different individual plastics and their mixtures with a dolomite supported Ni catalyst was evaluated in a drop-tube fixed-bed reactor. The influence of the Ni loading level and the interactions of mixed plastics during steam gasification were both examined. A 5 wt % NiO/dolomite catalyst gave the highest degree of carbon conversion for all evaluated plastics and mixtures. A mixture of the four types of plastic that matched the estimated weight ratio of real plastic waste revealed a lower gas yield than predicted, suggesting their interaction during gasification. The mixtures which contain high-density polyethylene or low-density polyethylene at 0.75 wt/wt led to a reduced gas production, while polystyrene increased it, especially in the polystyrene polypropylene binary mixture with a markedly higher H-2, CO, and CO2 production level than that expected. Thus, it would be beneficial to screen plastic types prior to the generation of suitable gas products.