Why is it necessary to control the levels of aromatics and olefins in gasoline and diesel? Thank you.

Olefins are a gasoline blending component with a high octane rating. However, it is a relatively reactive hydrocarbon; once volatilized into the atmosphere, it accelerates ozone formation through photochemical reactions, causing severe environmental pollution. On the other hand, due to the thermal instability of olefins, they can easily cause sludge and carbon deposits to form in engines and their intake systems. Due to the differences in refining methods between our country and other countries, catalytic cracked gasoline is the main component used in blending, which results in a higher content of olefins in the gasoline used for vehicles in our country. It is not possible in the near future to reduce the olefins content in our country’s gasoline to European and American levels. With the future increase in high-octane blending components such as reforming, alkylation, and isomerization, as well as the industrial application of catalysts that reduce the olefin content in catalytic cracked gasoline, the olefin content in gasoline in China will further decline. Aromatic hydrocarbons are gasoline blending components with high octane numbers and calorific values. However, when it burns, it causes the formation of the carcinogen benzene and increases CO2 emissions.

Olefins are a gasoline blending component with a high octane rating. However, it is a relatively reactive hydrocarbon; once volatilized into the atmosphere, it accelerates ozone formation through photochemical reactions, causing severe environmental pollution. On the other hand, due to the thermal instability of olefins, they can easily cause sludge and carbon deposits to form in engines and their intake systems. Due to the differences in refining methods between our country and other countries, catalytic cracked gasoline is the main component used in blending, which results in a higher content of olefins in the gasoline used for vehicles in our country. It is not possible in the near future to reduce the olefins content in our country’s gasoline to European and American levels. With the future increase in high-octane blending components such as reforming, alkylation, and isomerization, as well as the industrial application of catalysts that reduce the olefin content in catalytic cracked gasoline, the olefin content in gasoline in China will further decline. Aromatic hydrocarbons are gasoline blending components with high octane numbers and calorific values. However, when it burns, it causes the formation of the carcinogen benzene and increases CO2 emissions.

The quality standards for gasoline and diesel specify requirements in this regard; the reasons, as mentioned above, are essentially as follows: 1. To protect the engine. 2. To meet environmental emission standards and protect the environment. The National V standards for gasoline and diesel are set to be implemented on a mandatory basis soon, and currently refineries are making targeted investments to upgrade their oil products. While the focus of gasoline upgrading is deep desulfurization of catalytic gasoline and the increase in high-octane components, the focus of diesel upgrading is deep hydrodesulfurization and upgrading. However, the new standard for olefin content has also become more stringent, and various companies use a combination of processes such as gasoline etherification and hydroprocessing to ensure that their products meet the required standards.