HYDROPROCESSING OF DIZEL OIL FRACTIONS ON MODIFIED ALUMINA CATALYSTS

The paper presents the results of a study of hydroforming diesel oil fractions on alumina catalysts modified with metals of variable valency, the addition of phosphorus and lanthanum. The study of the process of hydroprocessing of the diesel fractions was carried out in a high-pressure flow unit with a stationary catalyst bed at temperature of 320-400 degrees C, a pressure of 3 - 4.0 MPa and a volume feed rate of 1-3 h(-1). The results obtained during the tests of catalysts in the process of hydroprocessing of diesel oil fractions show that the greatest decrease in the pour point and turbidity occurs at a temperature of 380-400 degrees C. During the hydroprocessing of the diesel fraction, the lowest residual sulfur content is observed at a temperature of 400 degrees C. During the hydroprocessing of the diesel fractions of oil, the catalyst CoO-WO3-La2O3 - P2O5-ZSM-Al2O3, has the greatest hydrodesulfurizing activity. The sulfur content of the catalysate with increasing temperature up to 400 degrees C decreased from 0,560 to 0,0229%. The greatest decrease in the pourpoint and cloudpoint, during the hydroprocessing of the diesel oil fraction is observed on the catalyst NiO-MoO3-La2O3-P2O5-ZSM-Al2O3: minus 58.9 and minus 57.7 degrees C, respectively. Physical and chemical characteristics of catalysts are studied. The method of temperature-programmed desorption of ammonia found that the highest concentration of acid centers has a catalyst NiO-MoO3-La2O3-P2O5-ZSM-Al2O3 (31.3.10(-4)mol NH3des /g cat) with T-des = 215 degrees C, which determines its high hydroisomerizing activity in the processes of hydroprocessing of diesel fractions. The developed catalysts make it possible to obtain winter grades of diesel fuels with low sulfur content.