Effect of inherent and additional pyrite on the pyrolysis behavior of oil shale

• Effect of inherent and additional pyrite on oil shale pyrolysis was investigated.
• Inherent pyrite leads to higher oil yield.
• Additional pyrite promotes the formation of volatiles in oil shale pyrolysis.
• Pyrite acts indirectly via sulfur on oil shale pyrolysis.

The effect of inherent and additional pyrite on oil shale pyrolysis was investigated in a fixed-bed reactor. The results show that at the temperature range of 460–580 °C, inherent pyrite can improve the oil yield, but the additional pyrite promotes the increase of volatiles. The oil and gas yields in oil shale pyrolysis at 500 °C with the addition of 8 wt.% pyrite are 41.7 wt.% and 14.4 wt.% (all in dry and ash-free basis), respectively, increasing by 4.5 wt.% and 3.3 wt.% compared to those from pyrolysis of raw oil shale. However, the additional pyrite has slightly effect on oil yield at higher temperature, but can enhance the gas yield. The results by TG-MS and XRD analyses indicate that the effect of additional pyrite on the pyrolysis behavior of oil shale is related with the pyrite decomposition.