Jens Michael Poulsen - Haldor Topsoe A/S
Refinery Fuel Gas (“RFG”) is an environmental liability which increasingly needs addressing globally.
In the short-term it is however the value potential of purified excess RFG which attracts most attention and effort. Cleaned RFG represents a very large value as feedstock for hydrogen units (steam reforming), replacing more expensive conventional feedstock such as natural gas, LPG and naphtha.
Furthermore, and for some refineries even more important, it represents an opportunity for 5- 20% increased hydrogen production. Many hydrogen units are limited in the expensive reforming section, and hydrogen-rich fuel gas provides the option of low-cost revamps for capacity increase without changing the reformer unit. As refineries increase hydroprocessing in order to upgrade and purify products (lower sulfur), increasingly they experience tightness or even shortage of hydrogen, and a capacity addition at low CAPEX is valuable.
At the same time, sulfur emissions are virtually eliminated.
Fuel Gas Hydrotreatment (“FGH”) can be integrated and optimized with the hydrogen unit, replacing the conventional HDS section, at low CAPEX as an existing RFG amine wash can be re-used.
Refinery Fuel Gases are inherently challenging to deal with due to large amounts of unwanted components including problematic sulfur species such as mercaptans and thiophenes, di- olefins and olefins, and not least a large compositional variability. Topsoe’s Fuel Gas Hydrotreatment is capable of dealing with a stream containing both up to 15% H2S and hundreds of ppms of other sulfur species, converting all sulfur species to H2S for subsequent downstream removal by a single amine wash – often repurposed from the existing fuel gas system.
The significant chemistry challenges will be discussed together with experimental results and the catalytical and process solutions, both for the fundamental RFG purification and for optimal integration with hydrogen units.