Diesel fuel is a blend of various middle distillate components separated at the refinery. The composition and characteristics of the diesel fuel blend changes daily if not hourly because of normal process variation, changing refinery processing conditions, changing crude oil diet or changing diesel fuel and kerosene market conditions. Regardless of the situation going on at the refinery or the market, the resultant diesel fuel must consistently meet established cloud point specifications.
To consistently meet the cloud point specifications, refiners are forced to blend their diesel fuels in such a way that the resultant blend is always on the low side of the cloud point specification even when the refining process adversely changes the fuel characteristics. This practice has the effect of producing several degrees of cloud point “giveaway” when the refinery is not experiencing adverse swings in product quality. This designed “giveaway” costs the refinery money by not letting the refinery optimize the value of their blend components.
By blending diesel fuel components closer to the cloud point specification or by raising distillation cut points, and only using cloud point depressants opportunistically to remediate over specification fuel blends, refiners can minimize cloud point giveaway, optimize their profit and market a more consistent diesel fuel product.
This paper discusses a statistical analysis of “cloud point giveaway”, the economics of cloud point giveaway, and shows how refiners can reduce cloud point giveaway to maximize refinery profit and help produce a more consistent diesel fuel product.