Fluid Catalytic Cracking Patents (V): Reactor Section – 2012-2013[1]

This is the fifth article in a review of recent patents in the area of Fluid Catalytic Cracking (FCC). The first four articles reviewed patents on catalyst additives, zeolites, cyclones, and cracking catalysts. The current article will cover seven patents relating to the FCC reactor system, which for the purposes of this article includes the riser(s), separation devices, stripper and the reactor vessel. The reactor section patents can generally be placed into two groups. The first group contains three patents: U.S. Patent Nos. 8,128,8078,349,170, and 8,383,051, and relate to the particular configuration of the riser and the primary/secondary separation devices. The second group contains two patents: U.S. Patent Nos. 8,354,018 and 8,394,259, which relate to dual riser systems. Another patent, U.S. Patent No. 8,124,020, relates to an apparatus containing a sulfiding agent line. While its claims are not limited to a dual riser system, they are described in the specification as being useful in such a system. A final patent, U.S. Patent No. 8,124,020, does not fall into the either of the above groups, but relates to the use of torch oil in a reactor stripper section. Review of the patents indicates a significant effort in reactor design research is ongoing, at least for the purposes of filing patent applications, since they are largely directed to fundamental aspects of the reactor/riser/separator configuration.


 The patents related to the reactor section are summarized below.  Table 1 lists relevant information in the patents.  Table 2 contains a representative independent claim from each.

 Reactor Section

In the first group of patents, U.S. Patent No. 8,128,807 describes a system where the riser 10 terminates in a primary separator 20 (Figure 1). Cracked hydrocarbon and catalyst are partially separated in the primary separator 20. The resultant gas stream is then routed from the riser 10 through a conduit 21 to multi-cyclone separator 30 comprising multiple cyclones 53 that extend through a tube sheet, where further catalyst removal is conducted. Catalyst particles separated in the multi-cyclone separator 30 are routed to the stripping section 26.

Click here to view table.

U.S. Patent No. 8,349,170 describes inter alia, a riser configuration consisting of a lower reactor riser section and an upper reactor riser section. The upper riser contains an upper conical shaped section which is connected at the large end of the cone to a cylindrical sleeve that fits concentrically around and overlaps a portion of the lower riser. The upper riser/conical section is in fluid contact (not mechanical contact) with the lower riser. Such a design is described as improving both mechanical reliability and process performance.

U.S. Patent No. 8,383,051 describes a compact riser separation system having an external riser 41 that enters a reactor vessel shell 51 from the outside via a crossover conduit 46.

Click here to view table.

In the second group of patents, U.S. Patent No. 8,354,018 describes a process for catalytically converting two feed streams in two separate reactors. Catalyst and a first hydrocarbon feed (for the first reactor 10), such as a virgin gas oil, is preheated in a wash column 30 by contacting it with a second cracked product stream from the second reactor 200, before feeding to the first reactor 10, to produce a first cracked product stream. Catalyst and a portion of the cracked products from the first reactor 10 are fed to second reactor 200 to form a second cracked product stream. Effluent from the first and second reactors is processed separately.

Click here to view table.

U.S. Patent No. 8,394,259 describes a process for producing gasoline and propylene. A first stream having a boiling point range of about 180°C to 800°C is catalytically cracked in a first reaction zone 100 (first riser 200/first reaction vessel 220). A second stream containing C4-C6 olefins is catalytically cracked in a second reaction zone 250 (second riser 260/second reaction vessel 280). A first mixture of catalyst and products from the first reaction zone 100 and a second mixture of catalyst and products from the second reaction zone 250 are received in a disengagement zone 440 contained by a shell.

Click here to view table.

U.S. Patent No. 8,124,020 describes an FCC apparatus having a riser 12, catalyst pipe 14, feed line 8, feed distributors 22, reactor vessel 20 in communication with the riser 12 for receiving products and catalyst from the riser 12, and a sulfiding agent line 186, distinct from the feed line, in communication with the riser 12. Addition of the sulfiding agent prevents excessive coke formation resulting from Metal Catalyzed Coking. The specification describes a dual riser system where the sulfiding agent line 186 is utilized in a second reactor 170. The second reactor feed can include C10-hydrocarbons, and preferably C4 to C10 olefins.

Click here to view table.

A final patent, U.S. Patent No. 8,506,795 describes a process for providing torch oil to a stripping section 250 of a first reaction zone 200. Torch oil is sometimes added to an FCC regenerator when the feed is so light as to produce insufficient amounts of coke to maintain the regenerator temperature. Addition of the torch oil to the regenerator sometimes results in hot spots that can sinter typical FCC catalysts, degrading their activity and yield selectivities. Adding the torch oil to the stripping section in this manner facilitates raising regenerator temperatures to desired levels. The specification describes a dual riser system where a light hydrocarbon feed is fed to a first riser 240, and heavy hydrocarbon fed to a second riser 340. Torch oil is added to stripping section 250 of the riser processing the light feed through line 144.

Click here to view table.

Table 1
FCC Patents — Reactor

Click here to view table.

Table 2.
FCC Reactor Claims

Click here to view table.