Cetane Improver

A Cetane Improver [′sē‚tān im′prüv·ər] is a chemical which has the effect of increasing a diesel fuel's Cetane number. A few examples are nitrates, nitroalkanes, nitrocarbonates and peroxides.

One of the main Cetane Improver additives manufactured today is 2-ethylhexyl nitrate (CAS n°: 27247-96-7) which starts to decompose at 130 °C. 2-ethylhexyl nitrate is the result of the reaction of 2-ethylhexanol and nitric acid.

Due to its chemical composition, a Cetane Improver additive has the faculty to decompose itself at lower temperature than Diesel fuel. The additive’s exothermic decomposition leads to successive fuel reactions that result in the start of the combustion at low temperature.

The effect of the additive varies with the fuel type, which itself depends on the quality of the crude oil and the way it is refined.

Diesel fuel is a fraction of a crude, mixed with several additives, compliant with various environmental constraints, in order to be commercialized and added into engines.

With the rise of environmental concerns, the fuel industry has been driven to lessen emissions and increase performance. Europe, for instance, has implemented a minimum Cetane Index (46) and Cetane Number (51) in its Diesel specification (EN590)

The crudes used by the refineries are more and more difficult to refine. This results in a Diesel fuel of lower ignition quality.

The use of Cetane Improver additives constitutes both a cost-effective and convenient way to reduce emissions and improve engine performance.

Refiners also use Cetane Improver additives in their Premium Diesel fuel for enhanced performances.

While gasoline needs a spark to be ignited, Diesel fuel requires only the combination of the right pressure and temperature to start the combustion, with no outside assistance. The Cetane Number is a key property of Diesel fuel, as it measures its aptitude to self-ignite in the combustion chamber.

...
Wikipedia