New gasoline desulfurization process

Alkali-free deodorization process? Since it is not possible to reduce the total sulfur content in gasoline, this process is likely no longer practical.

The traditional alkali-free deodorization process cannot reduce the sulfur content in gasoline to meet the National V standard, and it is being phased out; currently, S-Zorb units are increasingly used by Sinopec for gasoline desulfurization.

Using the S-Zorb device for gasoline desulfurization – doesn’t this also fail to meet the standards for Grade 5 gasoline?

The limit for gasoline desulfurization using the S-Zorb unit is 10 ppm.

Previously, the desulfurization of gasoline was mainly carried out using the alkaline washing method, but nowadays the two-stage hydrogenation process is more commonly used for FCC gasoline, and the alkaline washing method has been largely abandoned. Among the current mainstream technologies, only Sinopec’s RSDS involves the alkaline treatment of light gasoline, while heavy gasoline is treated through hydrogenation. The advantage of alkali washing for desulfurizing light gasoline is its low cost, while the disadvantage is that the total sulfur content is limited by the cut point between light and heavy gasoline; in other words, alkali washing can only remove thiol compounds, but not thiophene or similar substances. Moreover, the amount of alkaline slag discharged is large, and there are many environmental issues associated with the treatment of alkaline slag.

The total sulfur content after alkali-free deodorization remained unchanged, and disulfides were still present in the gasoline. The National V and National VI gasoline standards are no longer relevant. It can only be used for the removal of secondary thiols after hydrogenation.