engleski

The Improvement of Gas Oils Ecological Characteristics by Hydrodesulfurization Process

From the viewpoint of reducing the ecologically unfavorable sulfur and aromatics in petroleum fuels, the effects of hydrodesulfurization process s parameters, on chemical and physical characteristics of gas oils have been investigated. The tests have been performed at the experimental reactor "Andreas Hofer", within the temperature range from 320 to 380 °C, with H2/HC ratio of 200 and 300, with a constant space velocity of 1 1/h and a 40 bars pressure. The results show that the increase in the severity of process s conditions has had a favorable impact on hydrodesulfurization degree. At maximum process severity: temperature of 380 °C and H2/HC ratio of 300, sulfur redaction of 97.6 % for feedstock A and 97.5 % for feedstock B with regard to its content in the initial feed has been achieved. Chemical changes, monitored the use of the n-d-M method, have shown an increased share of paraffinic carbon (% CP), with a simultaneous reduction in the share of naphthenic (% CN) and cyclic (% CR) carbon. Also, reduction in the share of aromatic carbon (% CA) in the products, with regard to the feed applied, has been observed at lower process temperatures, which may be explained by the exothermal character of aromatic hydrogenation reactions. Increased content of aromatic carbon at higher process temperature s, especially at the temperature of 380 °C (% CA=21.00 for a 300 ratio) is associated with the favorable impact of temperature on endothermal reactions of naphthene dehydrogenation, generating aromatics. Performed analyses of the products' physical properties (density, viscosity, refractive index, molecular weight) have shown the expected reduction in the values of these properties with the increase of process severity. The effects of independent variables, calculated the use of 22 factorial designs, show the greatest effect of temperature on the products chemical and physical characteristics.

hydrodesulfurization, hydrotreatment, process parameters, gas oils, petroleum fuels

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