EGEE 439
Alternative Fuels from Biomass Sources

8.1 Review of Refinery Processing and Chemical Structures for Jet Fuel and Diesel Fuel

Recall from Lesson 2 the general schematic of a refinery, shown here in Figure 8.1. Jet fuel is typically in the middle distillate range, also known as naphtha and kerosene. Diesel fuel is heavier (higher molecular weight and longer long chain hydrocarbons). These fuels do not require as much processing because they can be obtained primarily from distillation of oil, but because of sulfur/oxygen/nitrogen functional groups and high molecular weight waxes, these fuels must have these components removed. They are hydrotreated (hydrogen is added, sulfur/oxygen/nitrogen are removed, and aromatics are made into cycloalkanes). Waxes are also separated out.

schematic of Primary processes that are typical in a petroleum refinery as described in the text
Figure 8.1: Primary processes that are typical in a petroleum refinery.
Credit: Dr. Caroline B. Clifford

The primary structure we want for jet fuel and diesel fuel is:

Alkane - atoms are lined up. For stick representation, each corner represents a CH2 group, and each end represents a CH3 group.
Name Atoms and Bonds Stick Representation
Heptane (7 C atoms) heptane heptane
Cycloalkanes - again, still an alkane, but forms a ring compound.
Name Atoms and Bonds Stick Representation
Cyclohexane (6 C atoms) cyclohexane cyclohexane

Table 8.1 also shows a list of different chemicals and the properties of each. This table is mainly focused on those chemicals that would be in jet and diesel fuels.

Table 8.1: List of common hydrocarbons and properties
Name Number of C Atoms Molecular formula bp (0C), 1 atm mp (0C) Density (g/mL)(@200C)
Decane 10 C10H22 174.1 -30 0.760
Tetradecane 14 C14H30 253.5 6 0.763
Hexadecane 16 C16H34 287 18 0.770
Heptadecane 17 C17H36 303 22 0.778
Eicosane 20 C20H42 343 36.8 0.789
Cyclohexane 6 C6H12 81 6.5 0.779
Cyclopentane 5 C5H10 49 -94 0.751
Benzene 6 C6H6 80.1 5.5 0.877
Naphthalene 10 C10H8 218 80 1.140
Tetrahydronaphthalene(tetralin) 10 C10H12 207 -35.8 0.970
Decahydronaphthalene(decalin) 10 C10H18 187,196 -30.4, -42.9 0.896