Technology

Coker Naphtha often contains high levels of Silica, which decrease HDN Catalyst activity. Complications can also arise because of high concentrations of conjugated Di-Olefins that tend to polymerize, as well as Olefins that immediately saturate and release heat that challenges temperature control. The Sulfur content of Coker Naphtha can be 20 times higher than in Straight-Run Naphtha.

The Coker Naphtha Hydrotreater needs to run under severe operating conditions to meet product specifications. The typical Coker Naphtha Hydrotreating Reactor Loop has three Stages:

1. The First Stage selectively saturates Diolefins to Olefins, which react quickly at high temperatures.
2. The Second removes Silica and saturates Monoolefins. If not removed, Silica quickly deactivates HDS/HDN Catalysts.
3. The Third Stage addresses the HDS/HDN Reactions and drives bulk conversion.

Source: Topsoe, Process Licensing, Coker naphtha hydrotreating technology