The diesel engine was conceptualized by Rudolph Diesel in 1893; in this engine, air is compressed, resulting in a rise in temperature. The design eliminated the need for an external ignition source, and the compression heat was enough to cause combustion with fuel. The early use of this engine was a stationary application to run heavy machinery. In the 1920s, the engine was redesigned into a smaller size that was suitable for the automobile industry. At the 1911 World's Fair in Paris, Dr. Diesel ran his engine on peanut oil and declared “the diesel engine can be fed with vegetable oils and will help considerably in the development of the agriculture of the countries which use it” (Nitschke and Wilson, 1965). The use of vegetable oil and transesterified vegetable oil continued for some time, and later the engine was reengineered to run only on petroleum fuel. Since then, diesel consumption has grown significantly (Figure 8.1), putting pressure on the world supply and environment.
Diesel from Petroleum
Currently, the main source of diesel is petroleum crude oil. The crude oil is separated by distillation into various fractions, which are further treated (e.g., cracking, reforming, alkylation, polymerization, and isomerization treatments) to produce saleable products. Figure 8.2 shows a schematic of a typical refining process and various products.
Crude oil is typically heated to 350–400°C and piped into the distillation column kept at atmospheric pressure.