In the last decade, the production of Chinese motor gasoline has been doubled, and the gasoline octane level has been significantly upgraded. However, China still produces approximately 70% of its total gasoline with a RON rating less than 90. Nowadays, the Chinese gasoline pool is largely composed of FCC naphtha, which comprises about 70% of the total gasoline production. The majority of refineries produce 90 RON gasoline containing nearly 90% FCC naphtha, whereas a few refineries produce 90 RON gasoline consisting of FCC naphtha only. As a result, Chinese gasoline differs from foreign gasoline in its high olefin content (mostly from 35 to 55 percent) with a high sensitivity ranging from 9 to 11, and its octane number declines from front to end in its full boiling range. In spite of its high olefin content, the induction period of gasoline is more than 480 min after dosing with anti-oxidant at the outlet of the FCC unit. The blending characteristics of FCC naphtha with other gasoline components, including MTBE, alcohols and other oxygenates, have been studied. In addition, a five-year storage test of FCC gasoline was conducted. It is shown that the difference in performance between stored gasoline and market gasoline is quite small with only minor physicochemical property changes, suggesting that the stored gasoline can be used without harm in practice.
Wang Xichu, Zhang Xing, Wang Youhui
Research Institute of Petroleum Processing
5th International Pacific Conference on Automotive Engineering