coke make, or allow higher throughput (Lapinski et al. 2006). The criteria for
selection of the best promoters include the impact on coke make, catalyst stability,
ability to function correctly over many oxidation-reduction cycles, ability to remain
on the catalyst (not volatile), and to not detrimentally affect other catalyst properties (Lapinski et al. 2010).
The process of moving catalyst through the reactors and from the reactors to the
regenerator and back requires the use of spherical catalysts, rather than cylindrical
extrudates. This is needed to minimize catalyst abrasion and breakage from interactions with other catalyst particles, reactor internals, and piping. Some breakage
over time is unavoidable, and small amounts of makeup catalyst are typically added
to the unit. The typical spherical diameters range between 1.5 and 1.9 mm with
densities in the range of 0.5–0.7 g/cm
3 . The catalyst is circulated at a rate
corresponding to about one regeneration per week or greater if needed based on
the deactivation under the selected operating conditions.
Catalyst Suppliers
For detailed up-to-date lists of catalysts and suppliers, the Oil and Gas Journal
periodically publishes a comprehensive review. The main suppliers of reforming
catalyst are currently Honeywell UOP LLC, UOP CH S.à.r.l., Nikki-Universal
Company, Ltd., and Axens IFP Group.
Deactivation and Regeneration
The deactivation mechanisms for reforming catalysts include poisoning, coking,
and agglomeration of the platinum. First, poisoning of metal and acid sites is
prevented or minimized by making sure that the naphtha hydrotreater is always
operating properly to remove N and S compounds and that the naphtha
hydrotreating catalyst is replaced before exceeding its capacity for adsorbing
metal poisons such as Si, As, and Pb. Fe is a corrosion product in the reforming
unit that builds up on the reforming catalyst over time. At higher Fe levels, Fe can
plug catalyst pores and/or negatively impact the selectivity of the metal function
leading to poorer yields. If the metal contaminants on the reforming catalyst
become excessive, a catalyst change-out is required.
Next, under normal reforming operating conditions, coke accumulates on the
reforming catalyst and activity is lost, and selectivity is debited at higher coke
levels. When the coke is burned in the regeneration step, if the Pt is not properly
redispersed, then some of the Pt will remain agglomerated. This results in some of
the Pt sites becoming inaccessible which can lead to non-optimum performance.
In an SR unit, coke deactivates the catalyst such that, in time, the temperature
limit of the reforming unit will be reached, or the selectivity to desired products is
too much reduced, or the octane of the liquid product is declining. When this
Catalytic Reforming in Petroleum Processing
249
selection of the best promoters include the impact on coke make, catalyst stability,
ability to function correctly over many oxidation-reduction cycles, ability to remain
on the catalyst (not volatile), and to not detrimentally affect other catalyst properties (Lapinski et al. 2010).
The process of moving catalyst through the reactors and from the reactors to the
regenerator and back requires the use of spherical catalysts, rather than cylindrical
extrudates. This is needed to minimize catalyst abrasion and breakage from interactions with other catalyst particles, reactor internals, and piping. Some breakage
over time is unavoidable, and small amounts of makeup catalyst are typically added
to the unit. The typical spherical diameters range between 1.5 and 1.9 mm with
densities in the range of 0.5–0.7 g/cm
3 . The catalyst is circulated at a rate
corresponding to about one regeneration per week or greater if needed based on
the deactivation under the selected operating conditions.
Catalyst Suppliers
For detailed up-to-date lists of catalysts and suppliers, the Oil and Gas Journal
periodically publishes a comprehensive review. The main suppliers of reforming
catalyst are currently Honeywell UOP LLC, UOP CH S.à.r.l., Nikki-Universal
Company, Ltd., and Axens IFP Group.
Deactivation and Regeneration
The deactivation mechanisms for reforming catalysts include poisoning, coking,
and agglomeration of the platinum. First, poisoning of metal and acid sites is
prevented or minimized by making sure that the naphtha hydrotreater is always
operating properly to remove N and S compounds and that the naphtha
hydrotreating catalyst is replaced before exceeding its capacity for adsorbing
metal poisons such as Si, As, and Pb. Fe is a corrosion product in the reforming
unit that builds up on the reforming catalyst over time. At higher Fe levels, Fe can
plug catalyst pores and/or negatively impact the selectivity of the metal function
leading to poorer yields. If the metal contaminants on the reforming catalyst
become excessive, a catalyst change-out is required.
Next, under normal reforming operating conditions, coke accumulates on the
reforming catalyst and activity is lost, and selectivity is debited at higher coke
levels. When the coke is burned in the regeneration step, if the Pt is not properly
redispersed, then some of the Pt will remain agglomerated. This results in some of
the Pt sites becoming inaccessible which can lead to non-optimum performance.
In an SR unit, coke deactivates the catalyst such that, in time, the temperature
limit of the reforming unit will be reached, or the selectivity to desired products is
too much reduced, or the octane of the liquid product is declining. When this
Catalytic Reforming in Petroleum Processing
249