Methods for forming light olefins by cracking

According to one or more embodiments presently disclosed, light olefins may be formed by a method that may comprise introducing a feed stream into a reactor, reacting the feed stream with a cracking catalyst in the reactor to form a product stream, and processing the cracking catalyst. The reactor may comprise an upstream reactor section and a downstream reactor section. The upstream reactor section may be positioned below the downstream reactor section. The upstream reactor section may have an average cross-sectional area that is at least 150% of the average cross-sectional area of the downstream reactor section.

BACKGROUND

Field

The present disclosure generally relates to chemical processing, and more specifically, to reactor designs and systems utilized in cracking reactions to from light olefins.

Technical Background

Light olefins may be utilized as base materials to produce many types of goods and materials. For example, ethylene may be utilized to manufacture polyethylene, ethylene chloride, or ethylene oxides. Such products may be utilized in product packaging, construction, textiles, etc. Thus, there is an industry demand for light olefins, such as ethylene, propylene, and butene. However, most light olefins must be produced by different reaction processes based on the given chemical feed stream, which may be a product stream from a crude oil refining operation.

BRIEF SUMMARY

There is a continued need for processes and apparatuses which are suitable for producing light olefins by cracking. Disclosed herein are apparatuses and methods for cracking hydrocarbon streams, such as naphtha or butane, to form light olefins. The process configurations presently disclosed, such as utilizing a reactor which comprises an upstream reactor section positioned below a downstream reactor section, where the upstream reactor section has an average cross-sectional area that is at least 150% of the average cross-sectional area of the downstream reactor section, are suitable for cracking of naphtha or butane to form light olefins. Such a reactor design may operate as a fast fluidized, turbulent, or bubbling bed upflow reactor in its upstream reactor section, and as a dilute phase riser reactor in its downstream reactor section.

Additionally, of advantage in some embodiments of the presently disclosed methods and reactor systems is the processing flexibility offered by the presently disclosed reactor design. In some embodiments, the reactor design disclosed herein may be utilized for additional processes, other than cracking, that can be utilized to make olefins from other feedstocks. For example, light olefins may be produced from a variety of feed stream by utilizing different catalysts. For example, light olefins may be produced by at least dehydrogenation reactions, cracking reactions, dehydration reactions, and methanol-to-olefin reactions. However, according to various embodiments, these reaction types may utilize different feed streams to form the light olefins. Non-limiting examples include utilizing a dehydrogenation reaction that may utilize a gallium and/or platinum catalyst to react a feed stream comprising one or more of ethane, propane, n-butane, and i-butane; a cracking reaction that may utilize a zeolite catalyst to react a feed stream comprising one or more of naphtha, n-butane, or i-butane; a dehydration reaction that may utilize an acid catalyst (such as alumina or zeolite) to react a feed stream comprising one or more of ethanol, propanol, or butanol; and a methanol-to-olefin reaction that may utilize a zeolite (such as SAPO-34) catalyst to react a feed stream comprising methanol.

In some embodiments, the presently disclosed reactors, which may be utilized for cracking reactions, may be suitable for other types of reactions. For example, the presently described reactor system may be also operable, in addition to cracking, to perform dehydrogenation, dehydration, and/or methanol-to-olefin reactions. This feature may allow for the selection of feedstocks based on their price and availability, decreasing costs in producing light olefins. As such, it should be understood that in some embodiments, the reactors and processes may purposefully not be fully optimized for cracking reactions, with the intent for allowing flexibility of the disclosed reactors for other reaction processes to form olefins.

Additionally, according to various embodiments, the reactor systems and methods described herein may utilize a supplemental fuel to heat the catalyst in a catalyst processing step. The supplemental fuel may be suitable for heating the catalysts of the presently described reactions because, unlike in many reactions which may form olefins, coke or other combustible materials may not be produced in sufficient quantity in the presently disclosed reactions. For example, the cracking of naphtha or butane may not form sufficient coke on the catalyst to burn to generate heat. Therefore, since heat is needed for the cracking reaction and it cannot be supplied by burning coke, a supplemental fuel source may be utilized, such as a liquid or vapor supplemental fuel source.

According to one embodiment, olefins may be formed by a method that may comprise introducing a feed stream into a reactor, reacting the feed stream with a cracking catalyst in the reactor to form a product stream, and processing the cracking catalyst. The reactor may comprise an upstream reactor section and a downstream reactor section. The upstream reactor section may be positioned below the downstream reactor section. The upstream reactor section may have an average cross-sectional area that is at least 150% of the average cross-sectional area of the downstream reactor section. The processing of the cracking catalyst may comprise passing the catalyst from the reactor to a combustor, burning a supplemental fuel source in the combustor to heat the catalyst, and passing the heated catalyst from the combustor to the reactor.

According to another embodiment, olefins may be formed by a method that may comprise introducing a feed stream into a reactor, reacting the feed stream with a cracking catalyst in the reactor to form a product stream, and processing the cracking catalyst. The reactor may comprise an upstream reactor section and a downstream reactor section. The upstream reactor section may operate as a fast fluidized or turbulent upflow reactor, and the downstream reactor section may operate as a plug flow reactor. The upstream reactor section may be positioned below the downstream reactor section. The upstream reactor section may have an average cross-sectional area that is at least 150% of the average cross-sectional area of the downstream reactor section. The processing of the cracking catalyst may comprise passing the catalyst from the reactor to a combustor, burning a supplemental fuel source in the combustor to heat the catalyst, and passing the heated catalyst from the combustor to the reactor.

According to another embodiment, olefins may be formed by a method that may comprise introducing a feed stream into a reactor, reacting the feed stream with a cracking catalyst in the reactor to form a product stream, and processing the cracking catalyst. The feed stream may comprise one or more of naphtha or butane, and the product stream may comprise one or more of ethylene, propylene, or butene. The reactor may comprise an upstream reactor section and a downstream reactor section. The upstream reactor section may be positioned below the downstream reactor section. The upstream reactor section may have an average cross-sectional area that is at least 150% of the average cross-sectional area of the downstream reactor section. The processing of the cracking catalyst may comprise passing the catalyst from the reactor to a combustor, burning a supplemental fuel source in the combustor to heat the catalyst, and passing the heated catalyst from the combustor to the reactor.

It is to be understood that both the foregoing brief summary and the following detailed description present embodiments of the technology, and are intended to provide an overview or framework for understanding the nature and character of the technology as it is claimed. The accompanying drawings are included to provide a further understanding of the technology, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments and, together with the description, serve to explain the principles and operations of the technology. Additionally, the drawings and descriptions are meant to be merely illustrative, and are not intended to limit the scope of the claims in any manner.

Additional features and advantages of the technology disclosed herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the technology as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

It should be understood that the drawings are schematic in nature, and do not include some components of a reactor system commonly employed in the art, such as, without limitation, temperature transmitters, pressure transmitters, flow meters, pumps, valves, and the like. It would be known that these components are within the spirit and scope of the present embodiments disclosed. However, operational components, such as those described in the present disclosure, may be added to the embodiments described in this disclosure.

Reference will now be made in greater detail to various embodiments, some embodiments of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts.

DETAILED DESCRIPTION

Embodiments related to methods for processing chemical streams are disclosed herein. In one or more embodiments, the chemical stream that is processed may be referred to as a feed stream, which is processed by a reaction to form a product stream. In one or more embodiments, the feed stream may comprise one or more of naphtha or butane. Butane is defined as either n-butane or iso-butane or a combination of both. The feed stream may be converted by reaction to a product stream which may comprise one or more of ethylene, propylene, or butene. Ethylene, propylene, and butene may be referred to herein as “light olefins.” As described herein, butene many include any isomer of butene, such as α-butylene, cis-β-butylene, trans-β-butylene, and isobutylene.

In one embodiment, the product stream may comprise at least 50 wt. % light olefins. For example, the product stream may comprise at least 60 wt. % light olefins, at least 70 wt. % light olefins, at least 80 wt. % light olefins, at least 90 wt. % light olefins, at least 95 wt. % light olefins, or even at least 99 wt. % light olefins.

In another embodiment, the feed stream may comprise at least 50 wt. % of naphtha. For example, the feed stream may comprise at least 60 wt. % naphtha, at least 70 wt. % naphtha, at least 80 wt. % naphtha, at least 90 wt. % naphtha, at least 95 wt. % naphtha, or even at least 99 wt. % naphtha. In another embodiment, the feed stream may comprise at least 50 wt. % butane. For example, the feed stream may comprise at least 60 wt. % butane, at least 70 wt. % butane, at least 80 wt. % butane, at least 90 wt. % butane, at least 95 wt. % butane, or even at least 99 wt. % butane. In yet another embodiment, the feed stream may comprise one or both of naphtha and butane, and the sum of naphtha and butane in the feed stream may be at least 50 wt. %. For example, the sum of naphtha and butane in the feed stream may be at least 60 wt. %, 70 wt. %, 80 wt. %, 90 wt. %, 95 wt. % or even 99 wt. %.

According to one or more embodiments, the reaction which converts the contents of the feed stream to the contents of the product stream may be a cracking reaction. A cracking reaction may break carbon-carbon bonds in a hydrocarbon. For example, in various cracking reactions, alkanes may be converted to shorter alkanes and alkenes. The cracking reaction may utilize a cracking catalyst. A cracking catalyst may be any catalyst capable of cracking one or more components of the feed stream. According to one embodiment, the cracking catalyst comprises one or more zeolites, such as ZSM-5 zeolite. In additional embodiments, the cracking catalyst may comprise, in addition to a catalytically active material, platinum. For example, the cracking catalyst may include from 0.001 wt. % to 0.05 wt. % of platinum. The platinum may be sprayed on as platinum nitrate and calcined at an elevated temperature, such as around 700° C. Without being bound by theory, it is believed that the addition of platinum to the catalyst may allow for easier combustion of supplemental fuels, such as methane.

Now referring toFIG. 1, an example reactor system102which may be suitable for use with the methods described herein is schematically depicted. However, it should be understood that other reactor system configurations may be suitable for the methods described herein. The reactor system102generally comprises multiple system components, such as a reactor portion200and/or a catalyst processing portion300. As used herein in the context ofFIG. 1, the reactor portion200generally refers to the portion of a reactor system102in which the major process reaction takes place, such as the cracking of naphtha or butane to form light olefins. The reactor portion200comprises a reactor202which may include a downstream reactor section230and an upstream reactor section250. According to one or more embodiments, as depicted inFIG. 1, the reactor portion200may additionally include a catalyst separation section210which serves to separate the catalyst from the chemical products formed in the reactor202. Also, as used herein, the catalyst processing portion300generally refers to the portion of a reactor system102where the catalyst is in some way processed, such as by combustion. The catalyst processing portion300may comprise a combustor350and a riser330, and may optionally comprise a catalyst separation section310. In some embodiments, the catalyst may be regenerated by burning off contaminants like coke in the catalyst processing portion300. In additional embodiments, the catalyst may be heated in the catalyst processing portion300. A supplemental fuel may be utilized to heat the catalyst in the catalyst processing portion300if coke or another combustible material is not formed on the catalyst, or an amount of coke formed on the catalyst is not sufficient to burn off to heat the catalyst to a desired temperature (which may be the case when cracking naphtha or butane). In one or more embodiments, the catalyst separation section210may be in fluid communication with the combustor350(e.g., via standpipe426) and the catalyst separation section310may be in fluid communication with the upstream reactor section250(e.g., via standpipe424and transport riser430).

As described with respect toFIG. 1, the feed stream may enter transport riser430, and the product stream may exit the reactor system102via pipe420. According to one or more embodiments, the reactor system102may be operated by feeding a chemical feed (e.g., in a feed stream) and a fluidized catalyst into the upstream reactor section250. The chemical feed contacts the catalyst in the upstream reactor section250, and each flow upwardly into and through the downstream reactor section230to produce a chemical product. The chemical product and the catalyst may be passed out of the downstream reactor section230to a separation device220in the catalyst separation section210, where the catalyst is separated from the chemical product, which is transported out of the catalyst separation section210. The separated catalyst is passed from the catalyst separation section210to the combustor350. In the combustor350, the catalyst may be processed by, for example, combustion. For example, and without limitation, the catalyst may be de-coked and/or supplemental fuel may be combusted to heat the catalyst. The catalyst is then passed out of the combustor350and through the riser330to a riser termination separator378, where the gas and solid components from the riser330are at least partially separated. The vapor and remaining solids are transported to a secondary separation device320in the catalyst separation section310where the remaining catalyst is separated from the gases from the catalyst processing (e.g., gases emitted by combustion of spent catalyst or supplemental fuel). The separated catalyst is then passed from the catalyst separation section310to the upstream reactor section250via standpipe424and transport riser430, where it is further utilized in a catalytic reaction. Thus, the catalyst, in operation, may cycle between the reactor portion200and the catalyst processing portion300. In general, the processed chemical streams, including the feed streams and product streams may be gaseous, and the catalyst may be fluidized particulate solid.

According to one or more embodiments described herein, the reactor portion200may comprise an upstream reactor section250, a transition section258, and a downstream reactor section230, such as a riser. The transition section258may connect the upstream reactor section250with the downstream reactor section230. According to one or more embodiments, the upstream reactor section250and the downstream reactor section230may each have a substantially constant cross-section area, while the transition section258may be tapered and does not have a constant cross-sectional area. As described herein, unless otherwise explicitly stated, the “cross-sectional area” refers to the area of the cross section of a portion of the reactor part in a plane substantially orthogonal to the direction of general flow of reactants and/or products. For example, inFIG. 1, the cross sectional area of the upstream reactor section250, the transition section258, and the downstream reactor section230is in the direction of a plane defined by the horizontal direction and the direction into the page (orthogonal to the direction of fluid motion, i.e., vertically upward inFIG. 1).

As depicted inFIG. 1, the upstream reactor section250may be positioned below the downstream reactor section230. Such a configuration may be referred to as an upflow configuration in the reactor202.

As described herein, the upstream reactor section250may include a vessel, drum, barrel, vat, or other container suitable for a given chemical reaction. In one or more embodiments, the upstream reactor section250may be generally cylindrical in shape (i.e., having a substantially circular cross-sectional shape), or may alternately be non-cylindrically shaped, such as prism shaped with cross-sectional shapes of triangles, rectangles, pentagons, hexagons, octagons, ovals, or other polygons or curved closed shapes, or combinations thereof. The upstream reactor section250, as used throughout this disclosure, may generally include a metallic frame, and may additionally include refractory linings or other materials utilized to protect the metallic frame and/or control process conditions. As depicted inFIG. 1, the upstream reactor section250may include a lower reactor portion catalyst inlet port252defining the connection of transport riser430to the upstream reactor section250.

The upstream reactor section250may be connected to a transport riser430which, in operation, may provide processed catalyst and/or reactant chemicals in a feed stream to the reactor portion200. The processed catalyst and/or reactant chemicals may be mixed with a distributor260housed in the upstream reactor section250. The catalyst entering the upstream reactor section250via transport riser430may be passed through standpipe424to a transport riser430, thus arriving from the catalyst processing portion300. In some embodiments, catalyst may come directly from the catalyst separation section210via standpipe422and into a transport riser430, where it enters the upstream reactor section250. The catalyst can also be fed via422directly to the upstream reactor section250. This catalyst may be slightly deactivated, but may still, in some embodiments, be suitable for reaction in the upstream reactor section250. As used herein, “deactivated” may refer to a catalyst which is contaminated with a substance such as coke, or is cooler in temperature than desired. Regeneration may remove the contaminant such as coke, raise the temperature of the catalyst, or both.

Still referring toFIG. 1, the reactor portion200may comprise a downstream reactor section230which acts to transport reactants, products, and/or catalyst from the upstream reactor section250to the catalyst separation section210. In one or more embodiments, the downstream reactor section230may be generally cylindrical in shape (i.e., having a substantially circular cross-sectional shape), or may alternately be non-cylindrically shaped, such as prism shaped with cross-sectional shape of triangles, rectangles, pentagons, hexagons, octagons, ovals, or other polygons or curved closed shapes, or combinations thereof. The downstream reactor section230, as used throughout this disclosure, may generally include a metallic frame, and may additionally include refractory linings or other materials utilized to protect the metallic frame and/or control process conditions.

According to some embodiments, the downstream reactor section230may include an external riser section232and an internal riser section234. As used herein, an “external riser section” refers to the portion of the riser that is outside of the catalyst separation section, and an “internal riser section” refers to the portion of the riser that is within the catalyst separation section. For example, in the embodiment depicted inFIG. 1, the internal riser section234of the reactor portion200may be positioned within the catalyst separation section210, while the external riser section232is positioned outside of the catalyst separation section210.

As depicted inFIG. 1, the upstream reactor section250may be connected to the downstream reactor section230via the transition section258. The upstream reactor section250may generally comprise a greater cross-sectional area than the downstream reactor section230. The transition section258may be tapered from the size of the cross-section of the upstream reactor section250to the size of the cross-section of the downstream reactor section230such that the transition section258projects inwardly from the upstream reactor section250to the downstream reactor section230.

In some embodiments, such as those where the upstream reactor section250and the downstream reactor section230have similar cross-sectional shapes, the transition section258may be shaped as a frustum. For example, for an embodiment of a reactor portion200comprising a cylindrical upstream reactor section250and cylindrical downstream reactor section230, the transition section258may be shaped as a conical frustum. However, it should be understood that a wide variety of upstream reactor section250shapes are contemplated herein which connect various shapes and sizes of upstream reactor section250and downstream reactor section230.

In one or more embodiments, the upstream reactor section250may have an average cross-sectional area that is at least 150% of the average cross-sectional area of the downstream reactor section230. As described herein, an “average cross-sectional area” refers to the mean of the cross-sectional areas for a given system component or section such as the upstream reactor section250or the downstream reactor section230. If the system component or section has a substantially constant cross-sectional area, such as the cylindrical shapes of the depicted upstream reactor section250or the downstream reactor section230, then the cross-sectional area at any point is about equal to the average cross-sectional area.

According to one or more embodiments, the upstream reactor section250may have an average cross-sectional area that is at least 160%, at least 170%, at least 180%, at least 190%, at least 200%, at least 250%, at least 300%, at least 400% or even at least 500% of the average cross-sectional area of the downstream reactor section230.

In one or more embodiments, based on the shape, size, and other processing conditions such as temperature and pressure in the upstream reactor section250and the downstream reactor section230, the upstream reactor section250may operate in a manner that is or approaches isothermal, such as in a fast fluidized, turbulent, or bubbling bed upflow reactor, while the downstream reactor section230may operate in more of a plug flow manner, such as in a riser reactor. For example, the reactor202ofFIG. 1may comprise an upstream reactor section250operating as a fast fluidized, turbulent, or bubbling bed reactor and a downstream reactor section230operating as a dilute phase riser reactor, with the result that the average catalyst and gas flow moves concurrently upward. As the term is used herein, “average flow” refers to the net flow, i.e., the total upward flow minus the retrograde or reverse flow, as is typical of the behavior of fluidized particles in general. As described herein, a “fast fluidized” reactor may refer to a reactor utilizing a fluidization regime wherein the superficial velocity of the gas phase is greater than the choking velocity and may be semi-dense in operation. As described herein, a “turbulent” reactor may refer to a fluidization regime where the superficial velocity of less than the choking velocity and is more dense than the fast fluidized regime. As described herein, a “bubbling bed” reactor may refer to a fluidization regime wherein well defined bubbles in a highly dense bed are present in two distinct phases. The “choking velocity” refers to the minimum velocity required to maintain solids in the dilute-phase mode in a vertical conveying line. As described herein, a “dilute phase riser” may refer to a riser reactor operating at transport velocity, where the gas and catalyst have about the same velocity in a dilute phase.

In one or more embodiments, the pressure in the reactor202may range from 6.0 to 44.7 pounds per square inch absolute (psia, from about 41.4 kilopascals, kPa, to about 308.2 kPa), but in some embodiments, a narrower selected range, such as from 15.0 psia to 35.0 psia, (from about 103.4 kPa to about 241.3 kPa), may be employed. For example, the pressure may be from 15.0 psia to 30.0 psia (from about 103.4 kPa to about 206.8 kPa), from 17.0 psia to 28.0 psia (from about 117.2 kPa to about 193.1 kPa), or from 19.0 psia to 25.0 psia (from about 131.0 kPa to about 172.4 kPa). Unit conversions from standard (non-SI) to metric (SI) expressions herein include “about” to indicate rounding that may be present in the metric (SI) expressions as a result of conversions.

In additional embodiments, the weight hourly space velocity (WHSV) for the disclosed process may range from 0.1 pound (lb) to 100 lb of chemical feed per hour (h) per lb of catalyst in the reactor (lb feed/h/lb catalyst). For example, where a reactor comprises an upstream reactor section250that operates as a fast fluidized, turbulent, or bubbling bed reactor and a downstream reactor section230that operates as a dilute phase riser reactor, the superficial gas velocity may range therein from 2 ft/s (about 0.61 m/s) to 10 ft/s (about 3.05 m/s) in the upstream reactor section250, and from 30 ft/s (about 9.14 m/s) to 70 ft/s (about 21.31 m/s) in the downstream reactor section230. In additional embodiments, a reactor configuration that is fully of a riser type may operate at a single high superficial gas velocity, for example, in some embodiments at least 30 ft/s (about 9.15 m/s) throughout.

In additional embodiments, the ratio of catalyst to feed stream in the reactor202may range from 5 to 100 on a weight to weight (w/w) basis. In some embodiments, the ratio may range from 10 to 40, such as from 12 to 36, or from 12 to 24.

In operation, the catalyst may move upward through the downstream reactor section230(from the upstream reactor section250), and into the separation device220. The separated vapors may be removed from the reactor system102via a pipe420at a gas outlet port216of the catalyst separation section210. According to one or more embodiments, the separation device220may be a cyclonic separation system, which may include two or more stages of cyclonic separation. In embodiments where the separation device220comprises more than one cyclonic separation stages, the first separation device into which the fluidized stream enters is referred to a primary cyclonic separation device. The fluidized effluent from the primary cyclonic separation device may enter into a secondary cyclonic separation device for further separation. Primary cyclonic separation devices may include, for example, primary cyclones, and systems commercially available under the names VSS (commercially available from UOP), LD2 (commercially available from Stone and Webster), and RS2 (commercially available from Stone and Webster). Primary cyclones are described, for example, in U.S. Pat. Nos. 4,579,716; 5,190,650; and 5,275,641, which are each incorporated by reference in their entirety herein. In some separation systems utilizing primary cyclones as the primary cyclonic separation device, one or more set of additional cyclones, e.g. secondary cyclones and tertiary cyclones, are employed for further separation of the catalyst from the product gas. It should be understood that any primary cyclonic separation device may be used in embodiments of the invention.

According to one or more embodiments, following separation from vapors in the separation device220, the catalyst may generally move through the stripper224to the catalyst outlet port222where the catalyst is transferred out of the reactor portion200via standpipe426and into the catalyst processing portion300. Optionally, the catalyst may also be transferred directly back into the upstream reactor section250via standpipe422. Alternatively, the catalyst may be premixed with processed catalyst in the transport riser430.

As is described in detail in accordance with the embodiment ofFIG. 1, according to one or more embodiments, the catalyst may be processed by one or more of the steps of passing the catalyst from the reactor202to the combustor350, burning a supplemental fuel source in the combustor350to heat the catalyst, and passing the heated catalyst from the combustor350to the reactor202.

Referring now to the catalyst processing portion300, as depicted inFIG. 1, the combustor350of the catalyst processing portion300may include one or more lower reactor portion inlet ports352and may be in fluid communication with the riser330. The combustor350may be in fluid communication with the catalyst separation section210via standpipe426, which may supply spent catalyst from the reactor portion200to the catalyst processing portion300for regeneration. The combustor350may include an additional lower reactor section inlet port352where air inlet428connects to the combustor350. The air inlet428may supply reactive gases which may react with the spent catalyst or a supplemental fuel to at least partially regenerate the catalyst. For example, the catalyst may be coked following the reactions in the upstream reactor section250, and the coke may be removed from the catalyst (i.e., regenerating the catalyst) by a combustion reaction. For example, oxidizer (such as air) may be fed into the combustor350via the air inlet428. Alternatively or additionally, such as when coke is not formed on the catalyst, a supplemental fuel may be injected into the combustor350, which may be burned to heat the catalyst. Following combustion, the processed catalyst may be separated in the catalyst separation section310and delivered back into the reactor portion200via standpipe424.

In one embodiment, a vapor supplemental fuel may be added to the combustor350and burned to heat the catalyst. For example, suitable vapor fuels may include methane, natural gas, ethane, propane, hydrogen or any gas that comprises energy value upon combustion. According to another embodiment, a liquid supplemental fuel may be added to the combustor350and burned to heat the catalyst. Suitable liquid supplemental fuels include, without limitation, fuel oil, kerosene, naphtha, heavy cracking products, or other liquids with suitable fuel value for combustion.

Referring NOW toFIG. 2, a cutaway elevational view of an embodiment of a combustor350suitable for use with the reactor system ofFIG. 1is depicted. Combustor350may include a lower portion368generally in the shape of a cylinder and an upper frustum section354. Spent or partially deactivated catalyst may enter the combustor350through standpipe426. The used catalyst may impinge upon and be distributed by splash guard356. The combustor350may further include air distributors358which are located at or slightly below the height of the splash guard356. Above the air distributors358and the outlet362of standpipe426is a grid360. Above the grid360are a plurality of fuel gas distributors364. One or more additional grids372may be positioned within the vessel above the fuel gas distributors364. Further details of embodiments which include injection means for vapor supplemental fuel are available in U.S. application Ser. No. 14/868,507, filed Sep. 29, 2015, which is incorporated by reference herein in its entirety.

In additional embodiments, the combustor350may include one or more liquid injection port(s)374. The liquid injection port may be utilized to inject liquid, combustible supplemental fuels into the combustor350. WhileFIG. 2depicts one liquid injection port374, it is contemplated that, in additional embodiments, two or more liquid injection ports374may be incorporated into the combustor350.

Now referring toFIG. 3, an overhead cross-sectional view of an embodiment of a liquid injection port374is schematically depicted. According to one or more embodiments, the liquid injection port374may utilize a coaxial design wherein an axial flow path398is surrounded by a co-axial flow path396. The axial flow path398may be defined by axial walls392, which may be pipe-shaped. Co-axial flow path396may surround axial flow path398and be defined as the space between axial wall392and co-axial wall382. Media may enter axial flow path398and co-axial flow path396through inlet390and inlet380, respectively, and flow towards nozzle388. The nozzle projects into the lower portion368of the regenerator (and through refractory material384) and sprays liquid supplemental fuel386. Walls394may project around the nozzle388to allow for the nozzle388to not be blocked by the refractory material384.

In one embodiment, liquid supplemental fuel may be passed through the axial flow path398and a gas, such as nitrogen, may be passed through the co-axial flow path396. The liquid fuel and gas may mix at or around the nozzle388, and the liquid fuel may be atomized as it is sprayed from the nozzle388.

Generally, “inlet ports” and “outlet ports” of any system unit of the reactor system102described herein refer to openings, holes, channels, apertures, gaps, or other like mechanical features in the system unit. For example, inlet ports allow for the entrance of materials to the particular system unit and outlet ports allow for the exit of materials from the particular system unit. Generally, an outlet port or inlet port will define the area of a system unit of the reactor system102to which a pipe, conduit, tube, hose, transport line, or like mechanical feature is attached, or to a portion of the system unit to which another system unit is directly attached. While inlet ports and outlet ports may sometimes be described herein functionally in operation, they may have similar or identical physical characteristics, and their respective functions in an operational system should not be construed as limiting on their physical structures.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Since modifications combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and their equivalents.