Evaluation of Approaches for Improving Diesel Cold Flow Properties

Four heavy diesel fractions (FBP according to ASTM D-2887 of about 420 degrees C), one lower boiling middle distillate fraction (FBP according to ASTM D-2887 of 310 degrees C) and kerosene fraction (FBP according to ASTM D-2887 of 271 degrees C) obtained from the Lukoil Neftochim Burgas (LNB) process units during the processing of Russian Export Crude Blend (REBCO) along with four heavy diesel fractions (FBP according to ASTM D-2887 of about 370 degrees C) obtained by fractionation of four crudes: Oil Blend, REBCO, Siberian Light Crude Oil (SLCO) and CPC (Caspian Consortium Pipeline) were investigated for their cold flow properties. It was found that undercutting diesel improves cloud point (CP) and cold filter plugging point (CFPP) by 4 degrees C/10 degrees C cut point. Blending of kerosene improves CP and CFPP by about 2 degrees C/10% added kerosene. The treatment with CP depressants may improve CP by about 2 degrees C if the proper combination diesel - depressant is selected and the improvement can reach up to 6 degrees C for a definite diesel. The treatment with CFPP depressant is much more efficient achieving an improvement of 18 degrees C. By assuming definite fuel prices (Plaits) and by applying the LNB linear programming model using Honeywell's RPMS software it was found that catalytic dewaxing is the most efficient approach for producing diesel with improved cold flow properties if the diesel yield from the dewaxing process is higher than 90%.