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

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

Recall from Lesson 2 the general schematic of a refinery, shown below. 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 the 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 is removed, and aromatics are made into cycloalkanes). Waxes are also separated out.

Primary processes that are typical in a petroleum refinery.

Click here for a text description of the figure.

This is a simple flow diagram of a crude oil refinery.

Crude oil enters and goes to distillation.

From distillation:

            LPG (gases) goes through alkylation to become O.N. 100 Motor Fuel Alkylate which can go on to become gasoline

            Straight-run gasoline goes through catalytic reforming to become O.N. 95 Reformate which can go on to become gasoline

            Naphtha, Kerosene, and Diesel all go through Hydrotreating and then dewaxing to become either treated Kerosene, Diesel (low sulfur) or lubricating oils.

            Fuel Oil goes through a catalytic cracker to become O/N 90-95 Gasoline

            Resid goes through Thermal Cracking to become either Carbon, Asphalt, or O.N. 75 Gasoline.

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)

Cycloalkanes - again, still an alkane, but form a ring compound.

Name	Atoms and Bonds	Stick Representation
Cyclohexane (6 C atoms)

The table below 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.