The straight-run kerosene often meets the requirements of total sulfur levels, ie less than 0.2% by weight, and the content of mercaptan, opposite - typically much higher than that required (max 0.003% to jet fuel requirements and 0.001% - for military jets).
Removal of mercaptan using a liquid-phase catalyst THIONOL occurs directly in the hydrocarbon environment, and in contrast to many known processes do not require use of aqueous alkali, thus we propose technology of alkali free sweetening process.
THIONOL catalyst comes in the form of water or oil soluble additive - the reagent. The catalyst does not contain toxic and corrosive components (alkali, formaldehyde, triazine etc.).
The reaction products – disulfides remain in the purified product, without affecting its properties.
Using the catalyst THIONOL an irreversible conversion of the mercaptans into neutral compound;
Implementation of sweetening based on THIONOL catalyst instead of the widely used hydrotreating might be interesting for refiners for the two reasons.
If straight-run kerosene has high sulfur content (more than 0.2%), and definitely should be hydrotreaated, it still does not mean that the process of sweetening in this situation is not wanted. On the contrary, if, for example, content of sulfur is 0.3%, it is enough only to process in hydrotreater a half of kerosene to achive 0.15% total sulfur. For the total control of mercaptan it is sufficient to treat the rest of kerosene feedstock in sweetening unit. This example is just a schematic illustration of the application of sweetening in conjunction with hydrotreating, even for cases with high sulfur feedstocks. On the contrary, when the refinery does not have sweetening process there is a need of deeper hydrotreating (greater than 70% of the total kerosene feedstock), which inevitably leads to decrease of quality of fuel with higher cost of treatment.