Interactions between oil shale and hydrogen-rich wastes during co-pyrolysis: 1. Co-pyrolysis of oil shale and polyolefins

Abstract Co-pyrolysis of oil shale and organic solid wastes rich in hydrogen is significant for improving shale oil quality and recycling wastes effectively and cleanly. This paper applied thermogravimetric system coupled with mass spectrometry system (TG-MS) to investigate pyrolysis characteristics of low density polyethene (LDPE) and polypropylene (PP), and explore their effects on the pyrolysis behaviors of oil shale during co-pyrolysis. These experiments proved that H radicals and H2 favored the interactions between plastics and oil shale. More specifically, the polymer chain of PP had more side groups than LDPE, and thus PP decomposed more easily and released more H radicals and H2 than LDPE. Accordingly, during the kerogen decomposition, thermogravimetric data indicated that interactions between oil shale and liquid PP were significant, while the interactions between oil shale and liquid LDPE were inconspicuous. However, the data from MS indicated the addition of plastics, especially minor addition of plastic, increased the volatiles of medium molecular weight, which implied that gaseous reactions between volatiles from LDPE and volatiles from oil shale were critical for final product distribution.