By converting the higher hydrocarbons contained in the natural gas to methane, the pre-reformer protects the plant against coke formation in the primary reformer feed preheat coil and catalyst tube inlet.
That increases the plant reliability. It also allows the steam/ carbon ratio to be reduced, which not only lowers energy consumption but also increases the attainable pre-heat temperature in the pre-reformed reformer feed, so reducing the radiant duty and cost of the primary reformer. Additionally, some steam reforming of the feed occurs in the pre-reformer, and that further reduces the load on the primary reformer.
Casale's pre-reforming reactor utilizes Casale’s extremely well-proven axial-radial flow catalyst bed technology. In an axial-radial catalyst bed, most of the gas passes through the catalyst bed in the radial direction, resulting in very low pressure drop. The balance passes down through a top layer of catalyst in an axial direction, thus eliminating the need for a top cover on the catalyst bed.