The relationship between olefins and octane number in gasoline hydrogenation
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In gasoline hydrogenation, are olefins primarily present in light gasoline, while aromatics are primarily present in heavy gasoline? Is there a specific quantitative relationship between olefins, aromatics, and octane number? In other words, how much octane number can the content of olefins and aromatics produce? Is there a one-to-one correspondence?
Isooctane (2,2,4-trimethylpentane) has good anti-knock properties, with an octane rating of 100. Heptane has poor anti-knock properties, assigned a value of 0. The determination of gasoline octane number is carried out using isooctane and n-heptane as reference fuels, under standard conditions, on a standard laboratory single-cylinder gasoline engine via a comparative method. For example, 98 gasoline has an octane rating of 98, which corresponds to the detonation resistance of a mixture consisting of 98% isooctane and 2% n-heptane.
Product name, Octane rating: Nonaane –45, Isooctane 100, N-Octane –17, Toluene 103.5, Heptane 0, Methanol 107, N-Pentane 62.5, Ethanol 108, 2-Pentene 80, Benzene 115, 1-Butene 97, Methyl tert-butyl ether 116, Ethylbenzene 98.9. The higher the octane rating, the greater the ability to prevent engine knocking
The source of raw materials for oxygenated gasoline generally allows it to be determined what the approximate composition of the raw materials before hydrogenation is; however, due to differences in crude oil types and primary processing methods, the composition of the raw materials used for hydrogenated gasoline also varies. This situation should be addressed by analyzing the group composition of the hydrogenation feedstock in order to determine the content and distribution of olefins and aromatics in the feed oil. For a mixture like gasoline, which consists of many components, it is difficult to quantify its octane rating based on just a few of those components, as other co-existing hydrocarbons also play a role in determining its octane rating. Generally, during gasoline hydrogenation, the octane number of the hydrogenated product decreases slightly, which is related to the degree of hydrogenation. You should read some basic materials on petroleum product processing as well as books on oil analysis.
Olefins are mainly present in light gasoline. Due to the high octane rating of olefins, in order to minimize the loss of octane in hydrogenated gasoline, as much light gasoline as possible is extracted.