Composition of Oil Fractions Obtained in Combined Thermolysis of Heavy Sulfur-Rich Petroleum and Oxidation of Activated Carbon with Supercritical Water–Oxygen Fluid

Abstract

The composition of oil fractions (OFs) obtained via the conversion of heavy sulfur-rich petroleum is studied with physicochemical methods. Petroleum is supplied to the upper part of a vertical tubular reactor packed with activated carbon (AC), through which a supercritical water-oxygen fluid is pumped. The experiment is carried out under the following conditions: pressure 30 MPa; temperatures in the upper, middle, and lower parts of the reactor of 673, 723, and 723 K, respectively; and the flow rates of oxygen, petroleum, and water of 0–3.5, 4, and 6 g/min, respectively. Time dependences between the wall temperature of the reactor and power of ohmic heaters show that the autothermal conversion regime is achieved due to heat release during the combustion of high-molecular petroleum components accumulated in the AC bed. The movement of a combustion front along the reactor axis is found. Isoprenoid and normal alkanes, 1-alkyl-2,3,6-trimethylbenzenes, and alkyl derivatives of benzothiophenes and dibenzothiophenes are the main components of OFs of the initial petroleum. A yield of OFs, whose content in the liquid products exceeds 90%, has an extreme dependence on the oxygen flow rate. An increase in the oxygen flow rate (and, consequently, an increase in temperature of the reaction mixture due to heat release during combustion) leads to an increase in the content of alkyl derivatives of bicyclic and tricyclic aromatic hydrocarbons, as well as benzothiophenes and dibenzothiophenes in OFs of the products. The content of components boiling at T < 493 K in OFs of the products increases 2–3-fold in comparison with those of the initial petroleum.