Vacuum pyrolysis of plant oil asphalt for transport fuel production catalyzed by alkali metal compounds

Plant oil asphalt (POA) is underutilized lipid-based biomass residue generated from the oleochemical industry. In this work, alkali metal compounds were used as catalysts for vacuum pyrolysis of POA. Their effects on the pyrolysis reaction rate, product yields and compositions were studied. The POA feed was characterized by proximate and ultimate analysis and inductively coupled plasma-mass spectrometry (ICP-MS). The pyrolytic oil was analyzed by gas chromatography–mass spectrometry (GC–MS), thermo-gravimetric analysis (TGA) and chromatography-simulated distillation analysis. The results showed that alkali metal compounds accelerated the pyrolysis reaction rate in the order of chlorides ≈ sulphates > hydroxides > carbonates > non-catalyst, and affected the yield of pyrolytic oil in the order of chlorides (80 wt.%) ≈ sulphates (77 wt.%) > non-catalyst (71 wt.%) > carbonates (68 wt.%) > hydroxides (55 wt.%). The quality of the pyrolytic oil was in the order of hydroxides > carbonates > non-catalyst ≈ chlorides ≈ sulphates.