Two-Step Pyrolysis of Refinery Fuel Oil to Olefins and Fuel

Document Type : Research Article


Faculty of Petrochemicals, Iran Polymer and Petrochemical Institute, Tehran, I.R. IRAN


In the present study, an efficient two-step thermal cracking process has been investigated for the conversion of refinery fuel oil to value-added products viz. olefins and liquid fuels. In the first step of the process, the low-ranked heavy feedstock was thermally treated in the liquid phase at completely mild operating conditions in order to remove undesirable species and obtain suitable products which indicates high potential for utilization as a feedstock in olefin units. The thermal treatment process was carried out at three different temperatures of 360, 400, and 440 °C. The activation energy was found to be 68.5 kJ/mol on the basis of the Arrhenius equation. Thermal analysis using the isoconversional Kissinger model at four temperature programs on the heavy feedstock led to an activation energy of 59.9 kJ/mol for the decomposition of the refinery fuel oil, being in reasonable agreement with that from the Arrhenius equation. More than 90% of the heavy feedstock was converted at 440 °C to products (mainly liquid products with a yield above 76 wt%). The obtained product was applied as a proper feedstock in the subsequent thermal cracking step, which was performed in vapor phase within a wider range of temperatures (550–750 °C). The yield of olefins in this step at 750 °C was more than 88 wt% based on the dry gas composition and more than 45 wt% based on the applied feedstock. By decreasing the temperature, the reaction tended to produce liquids than gases particularly gasoline and diesel fuel, such that at 550 °C, only 1 wt% of the obtained products were gaseous.


Main Subjects

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