Diesel fuel boiling range

Direct hydrohquefaction of biomass or wastes can be achieved by direct hydrogenation of wood chips on treatment at 10,132 kPa and 340 to 350°C with water and Raney nickel catalyst (45). The wood is completely converted to an oily Hquid, methane, and other hydrocarbon gases. Batch reaction times of 4 hours give oil yields of about 35 wt % of the feed the oil contains about 12 wt % oxygen and has a heating value of about 37.2 MJ /kg (16,000 Btu/lb). Distillation yields a significant fraction that boils in the same range as diesel fuel and is completely miscible with it. 

Naphthenic acids occur ia a wide boiling range of cmde oil fractions, with acid content increa sing with boiling point to a maximum ia the gas oil fraction (ca 325°C). Jet fuel, kerosene, and diesel fractions are the source of most commercial naphthenic acid. The acid number of the naphthenic acids decreases as heavier petroleum fractions are isolated, ranging from 255 mg KOH/g for acids recovered from kerosene and 170 from diesel, to 108 from heavy fuel oil (19). The amount of unsaturation as indicated by iodine number also increases in the high molecular weight acids recovered from heavier distillation cuts. 

Other properties of interest are carbon residue, sediment, and acidity or neutralization number. These measure respectively the tendency of a fuel to foul combustors with soot deposits, to foul filters with dirt and rust, and to corrode metal equipment. Cetane number measures the ability of a fuel to ignite spontaneously under high temperature and pressure, and it only applies to fuel used in Diesel engines. Typical properties ol fuels in the kerosene boiling range are given in Table 1. 

Middle distillate Liquid hydrocarbons boiling in the jet fuel, diesel fuel, and home heating oil ranges... 

Lower cloud point in the diesel fuel. Isoparaffins in the light cycle oil boiling range improve the cloud point. 

HTFT syncrude is easier to refine to on-specification transportation fuels than LTFT syncrude. This is partly due to its olefinic nature, giving it considerable synthetic ability, and partly due to the large proportion of material already in the fuels boiling range (C5-360°C). Historically fuels refining from HTFT syncrude focused mainly on motor gasoline production and only to a lesser extent on diesel fuel production. Jet fuel production became possible only recently (2008) with the international qualification of fully synthetic jet fuel. 

For convenience, boiling ranges are converted to the nearest 5°. Kerosene destined for conversion to diesel fuel crude kerosene is often quoted as having a wider boihng range [150-350°C (302-662° F)] before separation into various fuel and/or solvent products. 

Figure 2-14 Sketch of a trickle bed reactor used for hydroprocessingjaf the residual oil fraction of crude oil into tde boiling range used for gasoline and diesel fuel.

This situation can sometimes be manifested in the fuel distillation profile. More responsive fuels may have lower IBP and EP temperatures than poorly responsive fuels. Also, in poorly responsive fuels, a larger volume of fuel may distill within mid-boiling-point temperature fractions of the fuel distillation profile. The wax crystals which may form from these narrow boiling fractions tend to crystallize rapidly and at about the same temperature. Diesel fuel pumpability problems can be due to this narrow-boiling-point range wax fraction. 

Gas Oil A refinery fraction boiling within a typical temperature range between 330°F and 750°F (165.6°C and 398.9°C). Diesel fuel, kerosene, and heating oil fall into this fraction. 

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