Efficient styrene removal from refuse-derived fuel pyrolysis oil using waste hydroprocessing catalysts

Abstract

This study demonstrates that deactivated catalysts discarded by the hydroprocessing industry are effective for the partial hydrogenation of refuse-derived fuel pyrolysis oil. Both NiMo and CoMo catalysts exhibited high activity, reducing the styrene content of this oil by almost 85 %, which improves the oil processability in oil-refining facilities, as styrene is the main gum precursor in these operations. The process is optimized at 200ºC, a temperature significantly lower than those typically proposed for such treatments. Experimental results confirm that sulphur activates the metals and that the partial blockage of the alumina’s acidic sites by coke prevents undesired condensations, which would otherwise lead to rapid catalyst deactivation. This research demonstrates the feasibility of using waste (deactivated catalysts) to enhance the stability of a waste-derived raw material (refuse-derived fuel pyrolysis oil), thereby boosting its upgrading potential and supporting pyrolysis as a key player in the Circular Economy.