Direct conversion of poor-quality residual oil to light gases in electricity-driven thermal plasma reactor

Nowadays, the utilization of non-conventional oil resources has become an increasingly attractive solution for producing valuable chemicals and materials due to the depletion of conventional oil resources. Plasma technology, powered by renewable energy sources, provides a potential way to convert low-grade residual oil into lighter hydrocarbons in an environmentally friendly fashion. This study has developed a laboratory-scale plasma pyrolysis system to investigate the impacts of residual oil characteristics and operating variables such as residual oil-specific enthalpy, arc gas flow rate, arc gas composition, quenching, and plasma configuration. The results show that the higher specific enthalpy of the residual oil leads to higher yields of C-1, C-2, and H-2, particularly C2H2. An increment in the arc gas flow rate improves the pyrolysis impact; however, an excessively high arc gas flow rate lowers the thermal plasma jet's temperature, causing a limited pyrolysis effect. In the composition of arc gas, the increasing concentration of H-2 can enhance the specific enthalpy and improve carbon conversion from residual oil to gas products, both of which result in a higher yield of light gases. Furthermore, ethane gas has been used as a quenching medium after plasma pyrolysis. The results reveal that ethane can be cracked into ethylene and other products by taking full use of the heat energy of the gas. Meanwhile, the sharp decrease in the gas temperature inhibits the further pyrolysis of the main valuable products.

Automated summary

This study developed a laboratory-scale plasma pyrolysis system to investigate the impacts of residual oil characteristics and operating variables on the conversion of non-conventional oil resources. The results showed that higher specific enthalpy of the residual oil led to higher yields of valuable chemicals and materials. Additionally, ethane was found to be an effective quenching medium to improve the production, while controlling the gas temperature to prevent further pyrolysis.