Technology Type

Catalytic Reforming is a chemical process used to convert petroleum refinery Naphthas distilled from Crude Oil (typically having low Octane ratings) into high-octane liquid products called Reformates, which are premium blending stocks for high-octane Gasoline. The process converts low-octane linear hydrocarbons (paraffins) into branched alkanes (isoparaffins) and cyclic naphthenes, which are then partially dehydrogenated to produce high-octane aromatic hydrocarbons. The Dehydrogenation also produces significant amounts of byproduct Hydrogen gas, which is fed into other refinery processes such as Hydrocracking. A side reaction is hydrogenolysis, which produces light hydrocarbons of lower value, such as Methane, Ethane, Propane and Butanes^[1].

Figure 1 - Catalytic reforming reactions^[2].

Legend: (a) Naphtenes dehydrogenation to aromatics, (b) alkyl cyclopentanes dehydroisomerization to aromatics, (c) alkanes dehydrocyclization to aromatics, (d) n-alkanes isomerization to branched alkanes, and (e) cracking reactions to lower carbon products.

The most commonly used type of catalytic reforming unit has three reactors, each with a fixed bed of catalyst, and all of the catalyst is regenerated in situ during routine catalyst regeneration shutdowns which occur approximately once each 6 to 24 months. Such a unit is referred to as a Semi-Regenerative Catalytic Reformer (SRR)^[1].

Some catalytic reforming units have an extra Spare or Swing reactor and each reactor can be individually isolated so that any one reactor can be undergoing in situ regeneration while the other reactors are in operation. When that reactor is regenerated, it replaces another reactor which, in turn, is isolated so that it can then be regenerated. Such units, referred to as Cyclic Catalytic Reformers, are not very common. Cyclic Catalytic Reformers serve to extend the period between required shutdowns^[1].

The latest and most modern type of catalytic reformers are called Continuous Catalyst Regeneration (CCR) reformers. Such units are defined by continuous in situ regeneration of part of the catalyst in a special regenerator, and by continuous addition of the regenerated catalyst to the operating reactors. As of 2006, two CCR versions are available: UOP's CCR Platformer process and Axens' Octanizing process. The installation and use of CCR units is rapidly increasing^[1].

Many of the earliest catalytic reforming units (in the 1950s and 1960s) were non-regenerative in that they did not perform in situ catalyst regeneration. Instead, when needed, the aged catalyst was replaced by fresh catalyst and the aged catalyst was shipped to catalyst manufacturers to be either regenerated or to recover the Platinum content of the aged catalyst. Very few, if any, catalytic reformers currently in operation are non-regenerative^[1].

References

1. Source: Wikipedia, Catalytic Reforming.
2. J. Martinez et al., A Thermodynamic Analysis of Naphtha Catalytic Reforming Reactions to Produce High-Octane Gasoline, Processes 2022, 10(2), 313, DOI: 10.3390/pr10020313