About Diesel. Diesel is defined as any liquid fuel designed to work in a diesel engine. The most common type of diesel fuel is a hydrocarbon mixed fuel, containing mostly paraffins but also aromatic hydrocarbons and small amounts of olefins. It is a viscous, yellowish-green liquid that can be obtained from crude oil as a specific fractional distillate, with average chemical formula of C12H24. Diesel fuel originated in 1892 and is still the main fuel used for shipping goods and moving freight. In 2018, diesel accounted for about 20% of total U.S. petroleum consumption and about 22% of total petroleum consumption by the transportation sector. Diesel oil's popularity as a Fuel can be attributed to its high compression rate inside the combustion chamber, which translates to better motor efficiency.

There are several grades of Diesel Fuel with the key factor being the cetane rating, related to the quality of the Fuel's ignition. The higher the cetane rating, the easier it is to perform a cold start, which is particularly relevant in harsher environments and during cold seasons.

While Petroil derived Disel Fuel is the most common, this commodity can also be produced from syngas via a Fisher-Tropsh (FT) process, and from bio-oil via transesterification. Synthetic diesel has near zero sulfur content or other contaminants such as low aromatics, therefore it produces less toxic emissions and particulates. Biodiesel, although it also reduces emissions, has high acidity, which can cause corrosion in engines and storage tanks, so it usually requires extra processing steps.

Diesel will absorb water from the environment, causing it to break down and damage the engine that it is powering. It must be kept in dry places and away from heat (store below 20 °C), as Diesel may absorb more water when heated. The low Sulfur content makes the fuel a lot more prone to microbial activity, so biocides must be used. It should be kept away from ignition source as it may cause storage and transportation tanks to explode. Diesel should be stored in yellow containers for proper fuel type differentiation. Fuel can be transported from the refineries via pipelines, tank ships, rail tankers or road tank trucks. The shortening of the transport routes allows cost saving and reduces safety risks. Diesel fuels are assigned to hazard class III because their flash point is > 55ºC.

Diesel is used mainly as/in: truck fuel; railroad fuel; aircraft fuel; military vehicle fuel; car fuel; fuel for tractors and heavy equipments; power generation; and heating equipment.