Hydro-treatment may be applied to process oil feedstock with various quality grades. They can be oil products obtained both by means of primary oil distillation, and resulting from catalytic thermal processes.
Most often, hydro-treatment is used to produce jet fuel and low-sulfur fuel from sulfur and high-sulfur feedstock. Hydro-treatment of diesel fuel must occur at a temperature of 350-430ºC and under a pressure of 6.3 MPa.
Diesel fuel hydro-treatment plant provides a fast process at a temperature of 330-380°C using existing industrial catalysts. Since the reaction of hydrogen addition is characterized by a change of volume, the main impact on the depth of the process is made by the pressure in the reaction zone. The most common pressure for hydro-treatment is 2.5-5 MPa. If the pressure rises, it also increases the depth of full hydrogenation. Graded hydrogenation is considered to be most appropriate.
Speaking about the technological process of diesel fuel hydro-treatment, it is worth to note its complexity. To obtain optimal process temperature, it is necessary to take into account the quality of the feedstock, the activity of the catalysts and process conditions. If all other conditions are constant, the temperature growth can cause the increase in the degree of sulfur compounds hydrogenation from unsaturated hydrocarbons. Its maximum value is observed when the temperature reaches 420 °C. If the temperature continues to increase, it will be quite difficult to achieve a significant reduction in the depth of hydrogenation of sulfur compounds, although the same figure for aromatics will rise quite sharply.