In-situ sulphiding has some advantages in that the direct cost is lower (sulphiding agent compared with ex-situ sulphiding), the loading can be conducted under air (no inert atmosphere required) and the packaging cost is lower (Big Bags instead of drums or catalyst Flo-Bins). There are no processing losses such as those entailed in ex-situ catalyst sulphiding. In-situ sulphiding can, however, be difficult, due to the handling of the toxic sulphiding agent, the risk of releases as a result of leaks and associated neighbourhood complaints or refinery shutdown and the costs associated with bringing the sulphiding agent to the site (depending on the geographical location). Furthermore, in-situ sulphiding needs to be carried out carefully, so taking the unit to production takes longer than with an ex-situ sulphided catalyst. The recommendation therefore depends on the exact circumstances, but in general we are seeing broad acceptance and use of totally sulphided catalysts (ex-situ), despite higher direct costs.
