Upgrading of chlorinated oils coming from pyrolysis of plastic waste

• Low temperature thermal cracking upgrades chlorinated pyrolysis oils.
• Red Mud can act as dechlorination and cracking catalyst in the upgrading process.
• The process yields and products properties depend on the nature of the pyrolysis oil.
• Dechlorinated light oils are obtained by cracking pyrolysis oils with Red Mud at 325 °C.

The objective of this paper is the upgrading of chlorinated oils coming from the pyrolysis of mixed plastic waste, in order to use them as fuel or feedstock for refineries. Two different samples of pyrolysis oils have been thermally and catalytically cracked in a 300 mL autoclave at 325 °C and the auto-generated pressure. Thermal cracking converts the plastic pyrolysis heavy oils into light liquid fractions which are only composed of alkanes and aromatics. These light fractions present a very low quantity of chlorine compared to the initial oils and resemble gasoline and diesel-like products. Besides, a gaseous fraction rich in methane and with very high heating value is also produced, together with a fuel-like viscous product which remains in the autoclave. The relative proportions of each of these three fractions depend on the nature of the initial oils. Red Mud has proved to be a dehydrochlorination and cracking catalyst, since it gives rise to higher quantity of gases and light liquid fractions with a very low chlorine content (< 0.1 wt.%). Therefore, dechlorinated light oils can be obtained by Red Mud low temperature catalytic cracking of plastic derived chlorinated pyrolysis oils.