Reactor systems comprising fluid recycling

A method for processing a chemical stream includes contacting a feed stream with a catalyst in an upstream reactor section of a reactor having the upstream reactor section and a downstream reactor section, passing an intermediate product stream to the downstream reactor section, and introducing a riser quench fluid into the downstream reactor section, upstream reactor section, or transition section and into contact with the intermediate product stream and the catalyst to slow or stop the reaction. The method includes separating at least a portion of the catalyst from the product stream, passing the product stream to a product processing section, cooling the product stream, and separating a portion of the riser quench fluid from the product stream. The riser quench fluid separated from the product stream may be recycled back to the downstream reactor section, upstream reactor section, or transition section as the riser quench fluid.

BACKGROUND

Field

The present disclosure generally relates to chemical processing systems and, more particularly, to recycling processing quench fluid streams in chemical reactor systems.

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. Light olefins may be produced by different reaction processes depending on the given chemical feed stream, which may be a product stream from a crude oil refining operation. Many light olefins may be produced through catalytic processes, such as catalytic hydrogenation for example, in which the feed stream is contacted with a fluidized catalyst in a reactor system that facilitates conversion of the feed stream into the light olefins.

SUMMARY

Reactor systems for converting feed streams into light olefins and other products may include a reactor portion and a catalyst processing portion. The reactor portion of the reactor system may include an upstream reactor section, a downstream reactor section, and a transition section between the upstream reactor section and the downstream reactor section. The feed stream may be contacted with a catalyst at a reaction temperature in the reactor portion of the reactor system to produce an intermediate stream through one or more chemical reactions. Without some additional change to the system, such as the reduction of the temperature of the catalyst and/or intermediate product stream, reactants, intermediates, and/or products in the intermediate product stream passing through the reactor section may continue to react until a product stream is separated from the catalyst downstream of the downstream reaction section. However, continued reaction of reactants, intermediates, and/or products in the downstream reactor section may result in decreased selectivity of the reaction system and/or increased production of undesired by-products through side reactions or over-reaction of products in the presence of the catalyst.

To improve selectivity and/or to reduce production of undesired by-products, a riser quench fluid may be introduced to the downstream reactor section, an upper portion of the upstream reactor section, or the transition section to cool the catalyst and intermediate product stream to a temperature sufficiently low to slow or stop the catalyzed reactions. This may prevent continued reaction of reactants in side reactions and/or over-reaction of products in the intermediate product stream as the intermediate product stream and catalyst continue to pass through the reactor portion of the reactor system.

The riser quench fluid introduced to the downstream reactor section, upstream reactor section, or transition section may subsequently combine with the intermediate product stream passing out of the reactor system. In conventional processes, the riser quench fluid may be recovered from the reactor in a recovery process. For example, this recovered riser quench fluid may be condensed, separated and treated, before being returned to the process or otherwise disposed. This treatment may take the form of steam stripping or other treatment methods to remove organic compounds and/or other contaminants. However, the removal of the riser quench fluid from the system may undesirably place additional burden on existing facility treatment systems and add capital costs. Furthermore, the riser quench fluid condensed and recovered from the product stream may contain catalyst fines having a relatively high catalytic activity as compared with other catalyst in the system. These high-activity catalyst fines may be lost from the reactor system through treatment and disposition of the condensed riser quench fluid or from continued entrainment of the catalyst fines in the product gas stream.

According to one or more embodiments, the systems and methods disclosed herein may include a product processing section operable to both cool the product stream and remove at least a portion of the riser quench fluid from the product stream. At least a portion of the riser quench fluid removed from the product stream may be passed/recycled back to the downstream reactor section, upstream reactor section, and/or the transition section as the riser quench fluid and injected into the reactor. Additionally, the system and method may include a combustion gas processing section operable to cool the combustion gases discharged from the catalyst processing portion of the reactor system. At least a portion of a combustion gas quench fluid used to cool the combustion gas in the combustion gas processing section may also be recycled back to the downstream reactor section, upstream reactor system, or transition section so that the riser quench fluid includes the combustion gas quench fluid. Passing the riser quench fluid removed from the product stream, the combustion gas quench fluid, or both, back to the reactor (i.e., the upstream reactor section, downstream reactor section, or transition section) as the riser quench fluid may reduce the amount of processing fluids directed to and treated by the treatment systems and may enable recovery and recycling of high-activity catalyst fines back to the reactor system.

According to one embodiment, a method for processing a chemical stream may include contacting a feed stream with a catalyst in an upstream reactor section of a reactor system. The reactor system may include the upstream reactor section and a downstream reactor section, and the contacting of the feed stream with the catalyst may cause a reaction which forms an intermediate product stream. The method may further include passing at least a portion of the intermediate product stream and the catalyst from the upstream reactor section to the downstream reactor section and introducing a riser quench fluid into the downstream reactor section, the upstream reactor section, or a transition section between the downstream reactor section and the upstream reactor section and into contact with the at least a portion of the intermediate product stream and the catalyst in the downstream reactor section, the upstream reactor section, or the transition section to slow or stop the reaction of the intermediate product stream with the catalyst to form a product stream. The riser quench fluid may have a temperature less than a temperature of the intermediate product stream. The method may include separating at least a portion of the catalyst from the product stream in a catalyst separation section downstream of the downstream reactor section, passing at least a portion of the product stream and the riser quench fluid to a product processing section, and cooling the at least a portion of the product stream in the product processing section. The method may further include separating at least a portion of the riser quench fluid from the product stream in the product processing section. The riser quench fluid introduced to the downstream reactor section, the upstream reactor section, or the transition section may include the at least a portion of the riser quench fluid separated from the product stream.

According to another embodiment, a method for processing a chemical stream may include contacting a feed stream with a catalyst in an upstream reactor section of a reactor system. The reactor system may include the upstream reactor section and a downstream reactor section, and the contacting of the feed stream with the catalyst may cause a reaction which forms an intermediate product stream. The method may further include passing at least a portion of the intermediate product stream and the catalyst from the upstream reactor section to the downstream reactor section and introducing a riser quench fluid into the downstream reactor section, the upstream reactor section, or a transition section between the downstream reactor section and the upstream reactor system and into contact with the at least a portion of the intermediate product stream and the catalyst in the downstream reactor section, the upstream reactor section, or the transition section to slow or stop the reaction of the intermediate product stream with the catalyst to form a product stream. The riser quench fluid may have a temperature less than a temperature of the intermediate product stream in the downstream reactor section, upstream reactor section, or transition section. The method may further include separating at least a portion of the catalyst from the product stream in a catalyst separation section downstream of the downstream reactor section, passing at least a portion of the catalyst to a catalyst processing portion of the reactor system, and processing the at least a portion of the catalyst in the catalyst processing portion. Processing the catalyst may form a combustion gas and a processed catalyst. The method may further include passing at least a portion of the processed catalyst from the catalyst processing portion back to the upstream reactor section, passing the combustion gas to a combustion gas processing section, thermally contacting the combustion gas with a combustion gas quench fluid in the combustion gas processing section to cool the combustion gas in the combustion gas processing section and separate catalyst fines from the combustion gas, and passing at least a portion of the combustion gas quench fluid to the downstream reactor section, the upstream reactor section, or the transition section. The riser quench fluid may include the at least a portion of the combustion gas quench fluid.

According to yet another embodiment, a system for processing a chemical stream may include a reactor portion of a reactor system that includes an upstream reactor section, a downstream reactor section, a transition section between the upstream reactor section and the downstream reactor section, a riser quench fluid inlet positioned to introduce a riser quench fluid to the downstream reactor section, upstream reactor section, or transition section, and a separation device operable to separate a catalyst from a product stream. The system may further include a catalyst processing portion that includes a combustor configured to receive catalyst from the separation device and a separation section downstream of the combustor and configured to separate the catalyst from a combustion gas. The system may include a product processing section comprising a product stream inlet in fluid communication with the separation device, a quench fluid inlet operable to introduce a product quench fluid to the product processing section, a processed product stream outlet operable to pass a processed product stream out of the product processing section, and a quench fluid outlet fluidly coupled to the riser quench fluid inlet. The product processing section may be operable to reduce a temperature of the product stream, separate at least a portion of the riser quench fluid from the product stream, and pass the at least a portion of the riser quench fluid out of the quench fluid outlet, wherein the riser quench fluid comprises the at least a portion of the riser quench fluid separated from the product stream in the product processing section.

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

The reactor systems and methods disclosed herein may include recycle of the riser quench fluid recovered from the product stream in a product processing section, a combustion gas quench fluid from a combustion gas processing section, or both, to the downstream reactor section, upstream reactor section, or transition section as the riser quench fluid to reduce the temperature of the intermediate product stream and catalyst. Recycling the portion of the riser quench fluid separated from the product stream in the product processing section, the combustion gas quench fluid from the combustion gas processing section, or both, as the riser quench fluid introduced to the downstream reactor section, upstream reactor section, or transition section may reduce the amount of processing fluids directed to and treated by the treatment systems and may enable recovery and recycling of high-activity catalyst fines back to the reactor system.

In non-limiting examples, the reactor systems disclosed herein may be utilized to produce light olefins from hydrocarbon feed streams. Light olefins may be produced from a variety of feed streams by utilizing different catalysts and reaction mechanisms. For example, light olefins may be produced by at least dehydrogenation reactions, cracking reactions, dehydration reactions, and methanol-to-olefin reactions. These reaction types may utilize different feed streams which are subsequently reacted to form the light olefins. While the reactor systems are described herein in the context of hydrocarbon processing to form light olefins, it should be understood that it is contemplated that the reactor systems and methods described herein may be utilized in other types of reactor systems. As such, the presently described reactor systems and methods should not be limited only to embodiments of a hydrocarbon conversion system designed to produce light olefins, such as that depicted inFIG. 1.

The reactor systems and methods for processing the chemical streams will now be discussed in detail. 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. The feed stream may comprise a composition, and depending upon that feed stream composition, an appropriate catalyst may be utilized to convert the contents of the feed stream into a product stream that includes light olefins or other chemical products. For example, a feed stream may comprise at least one of propane, butane, ethane, or ethylbenzene, and the reaction system may be a dehydrogenation system in which the feed stream may be converted to light olefins through dehydrogenation in the presence of a dehydrogenation catalyst, such as a catalyst comprising platinum, palladium, and/or gallium. Other catalysts and reaction mechanisms may be utilized to form light olefins from a hydrocarbon feed stream.

Now referring toFIG. 1, an example reactor system102is schematically depicted. The reactor system102generally comprises multiple system components, such as a reactor portion200, a catalyst processing portion300, and a product processing section500. As used herein in the context ofFIG. 1, the reactor portion200generally refers to the portion of a reactor system102in which the major process reaction(s) takes place. For example, the reactor system102may be a dehydrogenation system in which the feed stream390is dehydrogenated in the presence of the dehydrogenation catalyst in the reactor portion200of the reactor system102. 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 system102in which 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. The catalyst may be regenerated by burning off contaminants like coke and/or heating the catalyst 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. 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 stream390may enter the transport riser430or the upstream reactor section250, and the product stream380may 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 stream390) and a fluidized catalyst into the upstream reactor section250. The chemical feed contacts the catalyst in the upstream reactor section250to form an intermediate stream. The intermediate stream and the catalyst each flow upwardly into and through the downstream reactor section230. The intermediate stream and the catalyst may continue to react in 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. The catalyst is separated from the chemical product in the separation device220. The chemical product is transported out of the catalyst separation section210as the product stream380. The separated catalyst is passed from the catalyst separation section210to the combustor350. In the combustor350, the catalyst may be processed by, for example, combustion. The catalyst may then be passed out of the combustor350and through the riser330to a riser termination separator378, where the combustion gas and solid components from the riser330are at least partially separated. The combustion gases and remaining solids are transported to a secondary separation device320in the catalyst separation section310where the remaining catalyst is separated from the combustion gases382produced 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 streams390and product streams380may 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. The upstream reactor section250may generally comprise a greater cross-sectional area than the downstream reactor section230. In some embodiments, such as those in which the upstream reactor section250and the downstream reactor section230have similar cross-sectional shapes, the transition section258may be shaped as a frustum. 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. The reactor202may also be a downflow reactor in which the upstream reactor section250may be position above the downstream reactor section230. Other reactor configurations are also contemplated for the reactor portion200of the reactor system102.

The upstream reactor section250may be connected to a transport riser430which, in operation, may provide processed catalyst and/or reactant chemicals in a feed stream390to 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. 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 section210, and an “internal riser section” refers to the portion of the riser that is within the catalyst separation section210. 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. Additional aspects of the reactor portion200of the reactor system102may be found in co-pending U.S. Provisional Patent Application Ser. No. 62/502,094, filed on May 5, 2017, which is incorporated by reference herein in its entirety.

As previously discussed, the intermediate product stream may continue to react in the presence of the catalyst in the downstream reactor section230until the catalyst is separated from the intermediate product stream in the catalyst separation section210. Continued reaction of the intermediate product stream may result in over-reaction of products formed by the reaction into other chemical by-products or may result in continued side reactions, which may reduce selectivity of the reactor system to the desired products and/or increase the production of undesired by-products.

Referring toFIG. 1, the downstream reactor section230may include a riser quench fluid inlet384positioned to introduce a riser quench fluid386to the reactor202(i.e., upstream reactor section250, downstream reactor section130, and transition section258). The riser quench fluid inlet384may be fluidly coupled to one or more cooling nozzles (not shown) for distributing the riser quench fluid386across the cross-sectional area of the reactor202. The riser quench fluid386may be introduced to the reactor202and into contact with the intermediate product stream and the catalyst in the reactor202. The riser quench fluid386may have a temperature less than a temperature of the intermediate product stream and catalyst in the reactor202. Contacting the riser quench fluid386with the intermediate product stream and the catalyst may slow or stop the reaction of the intermediate product stream with the catalyst to form a product stream. The product stream and the catalyst may then pass through the remaining portions of the reactor202and be separated from the catalyst in the catalyst separation section210. The product stream may include the product chemicals produced by the reaction as well as the riser quench fluid386, which may be vaporized upon introducing the riser quench fluid386to the reactor202. It is understood that the product stream380may also include unreacted materials from the feed stream, intermediate species formed in the reactor, by-products formed from side reactions or over-conversion of the product chemicals, other species, or combinations of these.

The riser quench fluid inlet384may be disposed at any position along the length L of the downstream reactor system230. For example, in some embodiments, the riser quench fluid inlet384may be positioned at the external riser section232of the downstream reactor section230to introduce the riser quench fluid386to the external riser section232. Alternatively, the riser quench fluid inlet384may be positioned at any position along the internal riser section234of the downstream reactor section230to introduce the riser quench fluid386to the internal riser section234. In alternative embodiments, the riser quench fluid inlet384may be positioned in an upper portion of the upstream reactor section250or in the transition section258between the upstream reactor section250and the downstream reactor section230. In some embodiments, the reactor202may include more than one riser quench fluid inlet384, and each of the riser quench fluid inlets384may be positioned in one of the downstream reactor section130, the upper portion of the upstream reactor section250, or the transition section258.

Thus, the riser quench fluid386may be introduced to the intermediate product stream and the catalyst at any point between the upper portion of the upstream reactor section250and the end of the downstream reactor section230before the catalyst separation section210. The positioning of the riser quench fluid inlet384may influence the progress of the reaction in the reactor202and, thus, may influence the conversion of the feed materials into the products. The riser quench fluid386may be a liquid or a gas. For example, the riser quench fluid386may include steam, liquid water, liquid hydrocarbon (e.g., a quench oil, fuel oil, or other hydrocarbon), or combinations of these. The liquid hydrocarbon may include hydrocarbons having greater than or equal to 6 carbon atoms, such as from 6 carbon atoms to 25 carbon atoms, or from 6 carbon atoms to 20 carbon atoms. In some embodiments, the riser quench fluid386may include water. Alternatively, in other embodiments, the riser quench fluid386may include liquid hydrocarbon, such as quench oil or fuel oil for example. In still other embodiments, the riser quench fluid386may include one or more than one of benzene, toluene, pyrolysis gas, or combinations of these. In some embodiments, the riser quench fluid386may also include particulate solids, such as catalyst particles for example.

The presence of catalyst particles in the riser quench fluid386will be discussed in subsequent sections of this disclosure.

The temperature of the riser quench fluid386may be less than the temperature of the intermediate stream and catalyst in the reactor202(i.e., the upstream reactor section250, downstream reactor section230, and transition section258) by greater than or equal to 100° C., greater than or equal to 200° C., greater than or equal to 300° C., greater than or equal to 400° C., or greater than or equal to 550° C.

Introduction of the riser quench fluid386to the reactor202may decrease the temperature of the intermediate product stream and catalyst in the reactor202. The decrease in the temperature of the intermediate product stream and the catalyst in the reactor202caused by introducing the riser quench fluid386may be sufficient to slow or stop the reactions of the intermediate product stream. For example, in some embodiments, the riser quench fluid386may reduce the temperature of the intermediate product stream and the catalyst by greater than or equal to 5° C., greater than or equal to 7° C., greater than or equal to at least 9° C., greater than or equal to 11° C., greater than or equal to 13° C., greater than or equal to 15° C., or greater than or equal to 20° C. Introduction of the riser quench fluid386to the reactor202may result in increased selectivity of the reaction in favor of selected products and may reduce formation of undesired by-products. Further examples of introducing a riser quench fluid386to a reactor system are disclosed in co-pending U.S. patent application Ser. No. 15/034,637, which is incorporated by reference herein in its entirety.

Referring toFIG. 1, in operation, introduction of the riser quench fluid386to the reactor202may stop or slow the reaction of the intermediate product stream to form the product stream. The product stream and the catalyst may move upward through the remaining portion of the reactor202(i.e., the portion downstream of the riser quench fluid inlet384), and into the separation device220. The separated vapors of the product stream380may 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 stage, 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.

According to some embodiments, following separation from vapors in the separation device220, the catalyst may generally move through the stripper224to the reactor 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 or coke deposited on the deactivated catalyst in the combustor350, 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 combustor350may also include a supplemental fuel inlet354for introducing a supplemental fuel to the combustor350. The air inlet428may supply reactive gases which may react with the spent catalyst or a supplemental fuel from the supplemental fuel inlet354to at least partially regenerate the catalyst. Additional details of the catalyst processing portion may also be found in U.S. Provisional Patent Application Ser. No. 62/502,094 previously incorporated by reference.

Referring toFIG. 1, the product stream380may be passed from the catalyst separation section210of the reactor portion200to a product processing section500positioned downstream of the catalyst separation section210. The product stream380may, optionally, be passed through a feed stream preheater392disposed downstream of the catalyst separation section210of the reactor portion200and upstream of the product processing section500. The feed stream preheater392may be a heat exchanger operable to heat the feed stream390through heat transfer from the product stream380to the feed stream390. Thus, the feed stream preheater392may reduce the temperature of the product stream380exiting the feed stream preheater392compared to the product stream380upstream of the feed stream preheater392.

Positioned downstream of the feed stream preheater392, the product processing section500may be operable to further reduce the temperature of the product stream380. The product processing section500may also be operable to remove at least a portion of the riser quench fluid386from the product stream380. Additionally, the product processing section500may be operable to remove catalyst fines and other particulate solids from the product stream380that were not separated from the product stream380in the catalyst separation section210. A product quench fluid510may be introduced to the product processing section500to provide cooling to the product stream380, remove at least a portion of the riser quench fluid from the product stream380, and/or remove entrained particulate solids (e.g., catalyst fines) from the product stream380.

The product quench fluid510may include steam, liquid water, liquid hydrocarbon (e.g., a quench oil, fuel oil, or other hydrocarbon), or combinations of these. The liquid hydrocarbon may include hydrocarbons having greater than or equal to 6 carbon atoms, such as from 6 carbon atoms to 25 carbon atoms, or from 6 carbon atoms to 20 carbon atoms. In some embodiments, the product quench fluid510may include water. Alternatively, in other embodiments, the product quench fluid510may include liquid hydrocarbon, such as quench oil or fuel oil for example. In still other embodiments, the product quench fluid510may include one or more than one of benzene, toluene, pyrolysis gas, or combinations of these. In some embodiments, the product quench fluid510may be the same as the riser quench fluid386.

Referring toFIG. 1, stream514may be passed out of the product processing section500and passed back to the riser quench fluid inlet384so that the riser quench fluid386introduced to the reactor202(i.e., the downstream reactor section230, the upstream reactor section250, or the transition section258) includes at least a portion of stream514. Stream514may be a liquid and may include the portion of the riser quench fluid386recovered from the product stream380. Additionally, stream514may include particulate solids, such as catalyst fines for example, recovered from the product stream380. In some embodiments, stream514may also include at least a portion of the product quench fluid510introduced to the product processing section500. As previously described, the riser quench fluid386introduced to the downstream reactor section230or other part of the reactor202may vaporize when contacted with the intermediate product stream and the catalyst in the reactor202. The vaporized riser quench fluid386may pass through the catalyst separation section210with the product stream380. In the product processing section500, at least a portion of the vaporized riser quench fluid386may be condensed and separated from the product stream380in the product processing section500and may be passed out of the product processing section500in stream514.

Passing stream514from the product processing section500back to the reactor202as the riser quench fluid386may reduce the quantity of stream514that, in some embodiments, must be treated before reuse or disposition of stream514. Passing stream514back to the reactor202as the riser quench fluid386may also improve the conversion and selectivity of the reactor system102by returning catalyst fines to the reactor system102.

Still referring toFIG. 1, the product processing section500may include a product stream inlet520in fluid communication with the gas outlet port216of the catalyst separation section210. The product inlet stream520may be in fluid communication with the separation device220through the gas outlet port216. In some embodiments, the optional feed stream preheater392may be disposed between the catalyst separation section210and the product processing section500such that fluid communication between the gas outlet port216and the product stream inlet520of the product processing section500may include fluid communication through the feed stream preheater392. The product processing section500may also include a processed product stream outlet522and a quench fluid outlet524. The processed product stream outlet522may be operable to pass a processed product stream512out of the product processing section500. In some embodiments, the processed product stream outlet522may be fluidly coupled to downstream processing systems for further processing the processed product stream512. The quench fluid outlet524may be fluidly coupled to the riser quench fluid inlet384of the to pass stream514back to the reactor system202as at least a portion of the riser quench fluid386. For example, the quench fluid inlet384may be positioned in the downstream reactor section230, the upper portion of the upstream reactor section250, or in the transition section258between the upstream reactor section250and the downstream reactor section230so that the stream514may be passed back to the downstream reactor section230, upstream reactor section250, or transition section258, respectively, as a portion of the riser quench fluid386. The product processing section500may also include a quench fluid inlet526operable to introduce the product quench fluid510to the product processing section500.

As previously discussed, the product processing section500may be operable to reduce a temperature of the product stream380. A temperature of the processed product stream512passed out of the product processing section500may be less than the temperature of the product stream380introduced to the product processing section500. For example, in some embodiments, the difference between the temperature of the product stream380introduced to the product processing section500and the temperature of the processed product stream512passed out of the product processing section may be from 50° C. to 500° C., from 50° C. to 400° C., from 50° C. to 300° C., from 50° C. to 200° C., from 100° C. to 500° C., from 100° C. to 400° C., from 100° C. to 300° C., or from 100° C. to 200° C.

The product processing section500may be operable to separate at least a portion of the riser quench fluid386from the product stream380. Thus, the weight percent of riser quench fluid386in the product stream380introduced to the product processing section500through the product stream inlet520may be greater than the weight percent of riser quench fluid386remaining in the processed product stream512passed out of the product processing section through the processed product stream outlet522. For example, in some embodiments, the product stream380introduced to the product processing section500may include greater than or equal to 5 wt. % riser quench fluid386based on the total weight of the product stream380. After processing the product stream380in the product processing section500, the processed product stream512passed out of the product processing section500through the processed product stream outlet522may comprise less than 5 wt. % riser quench fluid386. The product processing section500may be further operable to pass at least a portion of the riser quench fluid386separated from the product stream380out of the quench fluid outlet524as stream514.

As previously discussed, the product processing section500may be operable to remove particulate solids, including catalyst fines from the product stream380. In some embodiments, the processed product stream512may be substantially free of particulate solids, such as catalyst fines. As used herein, “substantially free” of a constituent refers to a composition, stream, reaction zone, vessel, reactor, catalyst, or other structure having less than 0.1 wt. % of the constituent based on the mass flow rate of the composition, stream, zone, reactor, catalyst, or other structure. For example, the processed product stream512that is substantially free of particulate solids may have less than 0.1 wt. % particulate solids based on the total mass flow rate of the processed product stream512.

Referring toFIG. 1, stream514may be passed from the product processing section500to the riser quench fluid inlet384as the riser quench fluid386and introduced to the reactor202to cool the intermediate product stream and catalyst in the reactor202. Passing stream514to the riser quench fluid inlet384to introduce stream514into the reactor202as the riser quench fluid386may reduce the amount of fluids conveyed to downstream processing and/or treatment systems, such as water treatment systems in the case of water as the quench fluid or downstream chemical processing systems in the case of hydrocarbon-based quench fluids. Additionally, catalyst fines transferred from the product stream380to stream514in the product processing section500may be reintroduced to the reactor system102by passing stream514to the reactor202as the riser quench fluid386.

It has been discovered that catalyst fines having particle-sizes smaller than the average particle-size of the catalyst in the reaction system102may contain a greater amount of a catalytically active material (e.g., platinum, palladium, gallium, etc.) per weight of catalyst than the larger particle-size catalyst. Referring toFIG. 6, the relative amount of platinum in a hydrogenation catalyst is shown as a function of the particle size of the catalyst for a used catalyst640and a new catalyst642. As illustrated inFIG. 6, for the used catalyst640, the relative amount of platinum may be greatest for the smallest sized catalyst particles and may decrease with increasing average particle size of the catalyst. Trend line644further graphically illustrates the decreasing relative amount of platinum with increasing average particle size for the used catalyst. For the new catalyst642, the relative amount of platinum in the catalyst is generally constant with respect to particle size. The increased relative amount of platinum in the used catalyst640having smaller average particle size has been shown to result in improved conversion of the feed stream153compared to the used catalyst640having larger average particle size.

The catalyst particles recovered from the product stream380in the product processing section500may be catalyst fines having a smaller average particle size compared to the average particle-size of the catalyst in the reactor system102and may, therefore, be expected to have a greater amount of catalytically active material (e.g., platinum, palladium, gallium, etc.) compared to the average catalyst particles in the reaction system. The catalyst particles recovered from the product stream380may be passed back to the reactor system102to enhance the reaction of the feed stream153with the catalyst to produce the product stream155. In particular, returning the recovered catalyst particles from the product processing section500to the reaction system102may improve the conversion and/or the selectivity of the reaction system102.

Referring back toFIG. 1, in some embodiments, the reactor system102may include a product-side solids concentrator504disposed downstream of the product processing section500. Stream514may be passed from the product processing section500to a product-side solids concentrator504. The product-side solids concentrator504may separate catalyst particles, such as catalyst fines, from stream514downstream of the product processing section500to produce catalyst fines516and stream518. Stream518may include a portion of the riser quench fluid separated from the product stream380as well as a portion of the product quench fluid introduced to the product processing section500. Stream518may be substantially free of catalyst particles upon passing out of the product-side solids concentrator504. For example, stream518may have less than 0.1 wt. % catalyst particles based on the total weight of stream518. The product-side solids concentrator504may include at least one of a liquid candle filter, a bag filter, a filter press, other solids concentrator, or combinations of these. In some embodiments, the product-side solids concentrator504may include at least one liquid candle filter.

Stream518may be passed from the product-side solids concentrator504to the riser quench fluid inlet384as a portion of the riser quench fluid386to quench the intermediate product stream and the catalyst in the reactor202(i.e., the downstream reactor section230, upstream reactor section250, and/or the transition section258). The catalyst fines516may be passed from the product-side solids concentrator504back to the reactor system102. For example, the catalyst fines516may be passed to the catalyst processing portion300or the upstream reactor section250of the reactor system102. In some embodiments, the catalyst fines516may be passed to the combustor350or section312of the catalyst processing portion300, where the catalyst fines516may be processed in catalyst processing portion300before being passed back to the upstream reactor section250. The catalyst fines516may include catalyst fines having a smaller average particle size relative to the average particle size of the catalyst in the reactor system102. As previously discussed, recovering the catalyst fines516from stream514and passing the catalyst fines516back into the reactor system102may improve the conversion and selectivity of the reactor system102due to the additional catalyst loading on the catalyst fines516.

Referring now toFIG. 2, in some embodiments, the product processing section500may include a quench tower system502. Referring toFIG. 2, the quench tower system502may include a quench tower528having a product inlet580, a gas outlet582, a liquid outlet584, a quench fluid recycle outlet586, and a quench fluid recycle inlet588. The quench tower528may also include outlet590positioned a lower portion690of the quench tower502. The product inlet580may be positioned in the lower portion690of the quench tower502so that gaseous portions of the product stream380may enter the lower portion690of the quench tower528and flow upward through the quench tower528to the gas outlet582disposed in a top of the quench tower528. The quench fluid recycle inlet588may be positioned in an upper portion692of the quench tower528so that the product quench fluid510introduced to the quench tower528flows generally downward through the quench tower528. The liquid outlet584may be positioned in the bottom of the quench tower528. In this configuration, the flow of the product stream380upward through the quench tower528may be countercurrent to the flow of product quench fluid510downward through the quench tower528. In some embodiments, the liquid outlet584may be the quench fluid outlet524of the product processing section500.

The quench tower528may further include a plurality of nozzles530fluidly coupled to the quench fluid recycle inlet588. A conduit may fluidly couple the nozzles530to the quench fluid recycle inlet588. The nozzles530may be oriented in the quench tower528to distribute the product quench fluid510downward and across at least a portion of the cross-sectional area of the quench tower528. In some embodiments, the nozzles530may be positioned to distribute the product quench fluid510across the entire cross-sectional area of the quench tower528. The nozzles530may be positioned in the top portion692of the quench tower528to maximize the volume of the quench tower528for contacting the product quench fluid510with the product stream380.

In some embodiments, the quench tower528may include a demister532positioned downstream of the nozzles530. When referring to the quench tower528, the term “downstream” is relative to the direction of flow of the product stream380through the vessel528. In the embodiment shown inFIG. 2, the flow of product stream380through the quench tower528is upward, and positioning the demister532downstream of the nozzles530places the demister532above the nozzles530, between the nozzles530and the gas outlet582. The demister532may capture droplets of the product quench fluid510entrained in the product stream380through contact between the product stream380and the product quench fluid510. The droplets of product quench fluid510captured by the demister532may include solid catalyst particles. The droplets of the product quench fluid510captured by the demister532may flow by gravity from the demister532downward through the quench tower528to combine with stream514in the lower portion690of the quench tower528.

Referring toFIG. 2, in some embodiments, the quench tower528may include a chimney tray536disposed in the lower portion690of the quench tower528between the product inlet580and the nozzles530. The chimney tray536may be operable to accumulate a volume of quench fluid flowing downward through the quench tower528. The quench fluid accumulated in the chimney tray536may include the product quench liquid510introduced to the quench tower528at the quench fluid recycle inlet588and/or riser quench fluid386separated from the product stream380in the product processing section500. The quench fluids accumulated in the chimney tray536may also include catalyst particles, such as catalyst fines, or other particulate solids. Quench fluid accumulated in excess of the fixed volume of the chimney tray536may overflow through the chimneys into the bottom of the quench tower528.

As shown inFIG. 2, the quench tower528may optionally include a gas/liquid contactor534positioned between the nozzles530and the chimney tray536. The gas/liquid contactor534may provide increased contact area between the gas phase of the product stream380and the liquid phase of the quench fluid510. The increased contact area between the product stream380and the product quench fluid510may improve the efficiency of heat transfer from the product stream380to the product quench fluid510and may improve the mass transfer of the catalyst fines from the product stream380to the product quench fluid510. The gas/liquid contactor534may include packing or trays, such as any commercially available packing or trays suitable for gas/liquid contacting. Examples of packing may include, but are not limited to, spheres, rings, structured packing, other packing, or combinations of these.

The quench tower system502may include a Venturi loop610that includes a Venturi contactor612disposed upstream of the product inlet580and a contactor pump614in fluid communication with the lower portion690of the quench tower528. In some embodiments, the product stream inlet to the Venturi contactor612may be the product stream inlet520of the product processing section500. The contactor pump614may be operable to pump liquid phase quench fluids (i.e., riser quench fluid386, product quench fluid510, or combinations thereof) accumulated in the lower portion690of the quench tower528to the Venturi contactor612. The Venturi contactor612may be operable to contact and mix the gaseous product stream380with liquid phase quench fluid drawn from the lower portion690of the quench tower528. Contact and mixing of the product stream380with the quench fluid in the liquid contactor612may transfer particulate solids from the gaseous phase of the product stream380to the liquid phase of the quench fluid.

Contacting and mixing the product stream380with the quench fluid from the lower portion690of the quench tower528may also reduce a temperature of the product stream380. In some embodiments, the quench fluid introduced to the Venturi contactor612may have a temperature that is 50° C. to 400° C. less than a temperature of the product stream380introduced to the Venturi contactor612. In some embodiments, the quench fluid temperature introduced to the Venturi contactor612may be less than the temperature of the product stream380introduced to the Venturi contactor612by from 50° C. to 300° C., from 50° C. to 200° C., from 50° C. to 150° C., from 75° C. to 500° C., from 75° C. to 300° C., from 75° C. to 200° C., or from 75° C. to 150° C. The Venturi contactor612may be fluidly coupled to the product inlet580of the quench tower528to introduce the mixture of the product stream380and the quench fluid to the quench tower528.

Referring toFIG. 2, the quench tower528may include a quench fluid recycle loop620that includes a quench fluid heat exchanger622and a quench fluid recycle pump624. The inlet end of the quench fluid recycle loop620may be fluidly coupled to the quench fluid recycle outlet586of the quench tower528, and the outlet end of the quench fluid recycle loop620may be fluidly coupled to the quench fluid recycle inlet588. The quench fluid recycle loop620may also be in fluid communication with a product quench fluid supply line626to provide fresh make-up product quench fluid510to the quench tower system502. In some embodiments, the junction of the product quench fluid supply line626with the quench fluid recycle loop620may effectively be the quench fluid inlet526of the product processing section500.

In operation, the quench fluid recycle pump624draws quench fluid (i.e., a mixture of riser quench fluid386separated from product stream380and the product quench fluid510) from the quench fluid accumulated in the chimney tray536of the quench tower528. The quench fluid recycle pump624circulates the quench fluid through the quench fluid heat exchanger622, which may be operable to remove heat from the quench fluid. The quench fluid is then passed through the quench fluid recycle inlet588of the quench tower528. The quench fluid then passes through the nozzles530and into the quench tower528. The quench fluid flows downward through the quench tower528and into contact with the gaseous product stream380, which is flowing upward through the quench tower528. The quench fluid recycle loop620may be operable to cool the product stream380passing through the quench tower528. The quench fluid recycle loop620may also be operable to further separate particulate solids from the product stream380.

The quench tower system502may also include a product gas processing loop630comprising a compressor632, a product gas heat exchanger634downstream of the compressor632, and a knock-out vessel636downstream of the product stream heat exchanger634. The gas processing loop630may be fluidly coupled to the gas outlet582of the quench tower528. The gas processing loop630may be operable to separate the riser quench fluid386, the product quench fluid510, or a combination of these from the product stream380to produce the processed product stream512passed out of the product processing section500. Quench fluids (i.e., riser quench fluids386, product quench fluids510, or both) may be passed from the knock-out vessel636back to the quench tower528. In some embodiments, the gas outlet of the knock-out vessel636may be the processed product stream outlet522of the product processing section500.

Referring toFIG. 2, in operation of the quench tower system502, the product stream380may be passed from the catalyst separation section210(FIG. 1), through the optional product stream heat exchanger392(FIG. 1), and into the Venturi contactor612of the Venturi loop610. In the Venturi contactor612, the product stream380may be contacted and mixed with quench fluid to reduce the temperature of the product stream380and transfer particulate solids, such as catalyst particles, from the product stream380into the liquid phase of the quench fluid. The mixture of the product stream380and quench fluid may be passed to the quench tower528through the product inlet580. The gaseous product stream380may flow upward through the quench tower528. Simultaneously, the liquid phase quench fluid (i.e., including the riser quench fluid386, product quench fluid510, or both) may be introduced to the quench tower528through the quench fluid recycle inlet588positioned in the upper portion692of the quench tower528. The nozzles530may distribute the product quench fluid510across the cross-sectional area of the quench tower528. The quench fluid may flow downward through the quench tower528. The liquid phase quench fluid may contact the gaseous product stream380flowing upward through the quench tower528. The temperature of the quench fluid may be less than the temperature of the product stream380so that heat may transfer from the product stream380to the quench fluid. Contact of the product stream380with the quench fluid in the quench tower528may further transfer particulate solids from the gas phase of the product stream380to the liquid phase of the quench fluid.

After thermally contacting and/or physically contacting the product stream380with the product quench fluid510, the product stream380may be passed through the demister532to remove any entrained liquid droplets or solid particles remaining in the product stream380. The product stream380may be passed from the quench tower528to the gas processing loop630. The gas processing loop630may separate riser quench fluid386, product quench fluid510, or both from the product stream380to produce the processed product stream512. The riser quench fluid386and/or the product quench fluid510separated from the product stream380may be recycled back to the quench tower528or the quench fluid recycle loop620to be combined with the product quench fluid510.

Thermally and/or physically contacting the product quench fluid510with the product stream380in the quench tower528may produce stream514. Stream514may include at least one of the product quench fluid510introduced to the product quench tower502, catalyst fines and other particulates recovered from the product stream380, riser quench fluid386separated from the product stream380, other compounds, or combinations of these. Stream514may flow generally downward towards the bottom of the quench tower528. Stream514may collect in the bottom portion690of the quench tower528and/or may be passed out of the quench tower528through the liquid outlet584.

Although the product processing section500is described herein as including the quench tower system502, it is contemplated that the product processing section500may alternatively include a heat transfer apparatus (not shown) and/or a mass transfer device (not shown) that may be configured in series or integrated into a unitary device. For example, the product processing section500may include a heat exchanger as the heat transfer apparatus to reduce the temperature of the product stream380and a gas/liquid contactor positioned downstream of the heat exchanger as the mass transfer device to remove the catalyst fines from the product stream380. Examples of heat exchangers may include, but are not limited to, shell and tube heat exchangers, plate and frame heat exchangers, other heat exchangers, or combinations thereof. In the heat exchanger of the product processing section500, the product quench fluid510may be thermally contacted with the product stream380by way of heat transfer surfaces in the heat exchanger, but may remain physically separated by the heat transfer surfaces. Examples of gas/fluid contactors may include, but are not limited to, particulate scrubbers or other gas/fluid contactors.

Continuously recycling the riser quench fluid386through the downstream reactor section230, catalyst separation section210, and product processing section500may result in the gradual buildup of contaminants in the recycled riser quench fluid386. Additionally recycling the riser quench fluid386may result in pH changes in the riser quench fluid386over time. In some embodiments, water may be used for the riser quench fluid386and the product quench fluid510. In these embodiments, the product processing section500may optionally include a stripper (not shown) to remove contaminants from the water circulated through the reaction system102as the riser quench fluid386. In other embodiments, the product processing section500may also optionally include a system for adjusting the pH of the riser quench fluid386recirculated through the reactor system102and product processing section500.

Referring now toFIG. 3, the combustion gases382from the catalyst processing portion300of the reactor system102may also be further processed in a combustion gas processing section540. The combustion gas382may be processed by thermally contacting the combustion gas382with a combustion gas quench fluid550in the combustion gas processing section540. The combustion gas quench fluid550may be passed from the combustion gas processing section540back to the reactor202(i.e., the downstream reactor section230, the upstream reactor section250, and/or the transition section258) as a portion of the riser quench fluid386to cool the intermediate product stream and the catalyst in the reactor202.

The combustion gas382may be passed from the secondary separation device320of the catalyst processing portion300to a combustion gas processing section540positioned downstream of the secondary separation device320. In some embodiments, the combustion gas382may pass through an optional combustion gas heat exchanger394disposed between the secondary separation device320and the gas processing section540. The combustion gas heat exchanger394may be operable to heat the feed stream390by heat transfer from the combustion gas382to the feed stream390. The combustion gas processing section540may be operable to reduce the temperature of the combustion gas382. Additionally, the combustion gas processing section540may be operable to remove catalyst fines from the combustion gas382that were not separated from the combustion gas382in the secondary separation device320. Any riser quench fluid386passed through the catalyst processing portion300of the reactor system102with the catalyst may also be separated from the combustion gas382in the combustion gas processing section540. In the combustion gas processing section540, a combustion gas quench fluid550may be introduced to the combustion gas processing section540to reduce the temperature of the combustion gas382and/or remove entrained solids, such as catalyst fines, from the combustion gas382. The combustion gas quench fluid550may be passed out of the combustion gas processing section540as stream554.

Stream554may include the combustion gas quench fluid550. Additionally, stream554may include solid particles, such as catalyst fines for example, which may be transferred from the combustion gas382to the product quench fluid510, and subsequently to stream554, in the combustion gas processing section540. Stream554may be passed back to the reactor202as at least a portion of the riser quench fluid386. Passing stream554from the combustion gas processing section540back to the reactor202as the riser quench fluid386may reduce the quantity of combustion gas processing fluid554that, in some embodiments, must be treated in treatment systems or downstream processing before reuse or disposition of stream554. Passing stream554back to the reactor202as the riser quench fluid386may also improve the conversion and selectivity of the reactor system102by returning catalyst fines to the reactor system102.

Still referring toFIG. 3, the combustion gas processing section540may include a combustion gas inlet560in fluid communication with the secondary separation device320. In embodiments in which the combustion gas heat exchanger394is disposed between the secondary separation device320and the combustion gas processing section540, fluid communication between the secondary separation device320and the combustion gas inlet560may include fluid communication through the combustion gas heat exchanger394. The combustion gas processing section540may also include a processed combustion gas outlet562operable to pass a processed combustion gas stream552out of the combustion gas processing section540. The combustion gas processing section540may also include a combustion gas quench fluid inlet566positioned to introduce the combustion gas quench fluid550to the combustion gas processing section540. The combustion gas processing section540may further include a combustion gas quench fluid outlet564fluidly coupled to the riser quench fluid inlet384of the reactor202at the downstream reactor section130, upstream reactor section250, and/or the transition section258to pass stream554back to the downstream reactor section230, upstream reactor section250, and/or the transition section258as at least a portion of the riser quench fluid386.

The combustion gas quench fluid550introduced to the combustion gas processing section540may include steam, liquid water, liquid hydrocarbon (e.g., a quench oil, fuel oil, or other hydrocarbon), or combinations of these. The liquid hydrocarbon may include hydrocarbons having greater than or equal to 6 carbon atoms, such as from 6 carbon atoms to 25 carbon atoms, or from 6 carbon atoms to 20 carbon atoms. In some embodiments, the combustion gas quench fluid550may include water. Alternatively, in other embodiments, the combustion gas quench fluid550may include liquid hydrocarbon, such as quench oil or fuel oil for example. In some embodiments, the combustion gas quench fluid550may be the same as the riser quench fluid386introduced to the reactor202. In other embodiments, the combustion gas quench fluid550may be the same as the riser quench fluid386and the product quench fluid510introduced to the product quench tower502.

Referring toFIG. 3, in operation of the combustion gas processing section540, the combustion gas382may be passed from the secondary separation device320, through the optional combustion gas heat exchanger394, and to the combustion gas processing section540. The combustion gas382may be thermally and/or physically contacted with the combustion gas quench fluid550in the combustion gas processing section540. Thermally contacting the combustion gas382with the combustion gas quench fluid550in the combustion gas processing section540may reduce the temperature of the combustion gas382. In some embodiments, a temperature of the processed combustion gas552passed out of the combustion gas processing section540may be less than a temperature of the combustion gas382introduced to the combustion gas processing section540by from 50° C. to 500° C., from 50° C. to 400° C., from 50° C. to 300° C., from 50° to 200° C., from 100° C. to 500° C., from 100° C. to 400° C., from 100° C. to 300° C., or from 100° C. to 200° C.

Physically contacting the combustion gas382with the combustion gas quench fluid550in the combustion gas processing section540may remove particulate solids from the combustion gas382. In some embodiments, the processed combustion gas552may be substantially free of particulate solids, such as catalyst fines. For example, the processed combustion gas552passed out of the combustion gas processing section540may have less than 0.1 wt. % particulates based on the total weight of the processed combustion gas552.

Thermally and/or physically contacting the combustion gas quench fluid550with the combustion gas382in the combustion gas processing section540may produce stream554. Stream554may include the combustion gas quench fluid550introduced to the combustion gas quench tower542, catalyst fines and other particulates recovered from the combustion gas382, other compounds, and/or combinations of these. Stream554may have a temperature greater than the temperature of the combustion gas quench fluid550introduced to the combustion gas quench tower542but less than a temperature of the intermediate product stream and catalyst in the reactor202. Stream554may be passed out of the combustion gas processing section540through the combustion gas quench fluid outlet564.

In some embodiments, the combustion gas processing section540may include a combustion gas quench tower system (not shown). The combustion gas quench tower system may include any of the features previously described herein in relation to the quench tower system502illustrated inFIG. 2and previously described herein. For example, the combustion gas quench tower system may include the quench tower528, which may include the nozzles530, the demister532, the chimney tray536, and and/or the gas/liquid contactor534, as illustrated inFIG. 2. The combustion gas quench tower system may also include one or more of the contacting loop610that includes the Venturi contactor612and the contactor pump614; the quench fluid recycle loop620that includes a quench fluid heat exchanger622and a quench fluid recycle pump624; and/or a gas processing loop630that includes the compressor632, gas processing heat exchanger634, and the knock-out vessel636. In some embodiments, the gas inlet to the Venturi contactor612(FIG. 2) may be the combustion gas inlet560(FIG. 3) of the combustion gas processing section540. In some embodiments, the gas outlet of the knock-out vessel636(FIG. 2) of the gas processing loop630(FIG. 2) may be the combustion gas outlet562(FIG. 3) of the combustion gas processing section540. Alternatively, in other embodiments, the gas outlet of the quench tower528(FIG. 2) may be the combustion gas outlet562(FIG. 3) of the combustion gas processing section540. In some embodiments, the liquid outlet584(FIG. 2) of the quench tower528(FIG. 2) may be the combustion gas quench fluid outlet564(FIG. 3) of the combustion gas processing section540.

Although described herein as having the combustion gas quench tower system, it is contemplated that the combustion gas processing section540may alternatively include a heat transfer device (not shown) and a mass transfer device (not shown) that may be configured in series or integrated into a unitary device. For example, the combustion gas processing section540may include a heat exchanger to reduce the temperature of the combustion gas382and a scrubber positioned downstream of the heat exchanger to remove the catalyst fines from the combustion gas382. In the heat exchanger of the combustion gas processing section540, the combustion gas quench fluid550may be thermally contacted with the combustion gas382by way of heat transfer surfaces in the heat exchanger, but may remain physically separated by the heat transfer surfaces.

Referring toFIG. 3, stream554may be passed from the combustion gas processing section540to the riser quench fluid inlet384as the riser quench fluid386and introduced to the reactor202to cool the intermediate product stream and catalyst in the reactor202. Passing stream554to the riser quench fluid inlet384to introduce stream554into the reactor202as the riser quench fluid386may, in some embodiments, reduce the amount of fluids conveyed to downstream processing and/or treatment systems, such as water treatment systems in the case of water as the quench fluid or downstream chemical processing systems in the case of hydrocarbon-based quench fluids. Additionally, catalyst fines transferred from the combustion gas382to stream554in the combustion gas processing section540may be reintroduced to the reactor system102by passing stream554to the reactor202as the riser quench fluid386. Re-introduction of catalyst fines to the reactor system102may improve conversion and product selectivity of the reactor system102.

Referring toFIG. 3, in some embodiments, the reaction system102may include a combustion gas solids concentrator544, and stream554may be passed from the combustion gas processing section540to the combustion gas solids concentrator544. The combustion gas solids concentrator544may separate the catalyst particles from stream554downstream of the combustion gas processing section to produce catalyst fines516and stream558. Stream558may be substantially free of catalyst particles upon passing out of the combustion gas solids concentrator544. The combustion gas solids concentrator544may include at least one of a liquid candle filter, a bag filter, a filter press, other solids concentrator, or combinations of these. In some embodiments, the combustion gas solids concentrator544may include at least one liquid candle filter.

As shown inFIG. 3, stream558may be passed from the combustion gas solids concentrator544to the reactor202as at least a portion of the riser quench fluid386to cool the intermediate product stream and the catalyst in the reactor202. The catalyst fines516may be passed from the combustion gas solids concentrator544back to the reactor system102. For example, the catalyst fines516may be passed to the catalyst processing portion300or the upstream reactor section250of the reactor system102. In some embodiments, the catalyst fines516may be passed to the combustor350or section312of the catalyst processing portion300, where the catalyst fines516may be processed in catalyst processing portion300before being passed back to the upstream reactor section250. As previously discussed, the catalyst fines516from the combustion gas solids concentrator544may include catalyst fines having a smaller average particle size relative to the average particle size of the catalyst in the reactor system102. Recovering the catalyst fines516from stream554and passing the catalyst fines516back into the reactor system102may improve the conversion and selectivity of the reactor system102due to the additional catalyst loading on the catalyst fines that comprise the catalyst fines516.

Referring toFIG. 4, the reactor system102that includes both the product processing section500for processing the product stream380and the combustion gas processing section540for processing the combustion gas382is schematically depicted. As shown inFIG. 4, the riser quench fluid386may include stream514passed out of the product processing section500, stream554passed out of the combustion gas processing section540, or both stream514and stream554. In embodiments, stream514and stream554may be combined to form the riser quench fluid386upstream of the riser quench fluid inlet384, through which the riser quench fluid386is introduced to the reactor202(i.e., the downstream reactor section230(FIG. 1), the upstream reactor section250(FIG. 1), and/or the transition section258(FIG. 1)). Alternatively, in some embodiments, stream514may be passed to and through the product-side solids concentrator504to form stream518and the catalyst fines516, and stream554may be passed to and through the combustion gas solids concentrator544to form stream558and the catalyst fines516. In these embodiments, the riser quench fluid386may include stream518passed out of the product-side solids concentrator504, stream558passed out of the combustion gas solids concentrator544, or both. Stream518and stream558may be combined to form the riser quench fluid386upstream of the riser quench fluid inlet384.

Referring now toFIG. 5, another configuration of the reactor system102that includes both the product processing section500and the combustion gas processing section540is schematically depicted. As shown inFIG. 5, stream514passed out of the product processing section500and stream554passed out of the combustion gas processing section540may be passed to a common solids concentrator570to produce stream572and the catalyst fines516. The common solids concentrator570may include at least one of a liquid candle filter, a bag filter, a filter press, other solids concentrator, or combinations of these. In some embodiments, the common solids concentrator570may include at least one liquid candle filter. Stream572may be passed from the common solids concentrator570to the riser quench fluid inlet384as at least a portion of the riser quench fluid386that is introduced to the reactor202to cool the intermediate product stream and the catalyst. The catalyst fines516may be passed from the common solids concentrator570back to the reactor system102. For example, the catalyst fines516may be passed back to the catalyst processing portion300of the reactor system102, the upstream reactor section250, or both. Passing both stream514and stream554to the common solids concentrator570may reduce the number of solid concentrators from two solid concentrators (i.e., the product-side solids concentrator504and the combustion gas solids concentrator544) to only one solid concentrator (i.e., common solids concentrator570).

According to one or more embodiments, the reaction conducted in the reaction system102may be a dehydrogenation reaction. According to such embodiments, the feed stream may comprise one or more of ethane, propane, n-butane, and i-butane. For example, if the reaction is a dehydrogenation reaction, then the feed stream may comprise one or more of ethane, propane, n-butane, and i-butane. In some embodiments, the feed stream may comprise at least 50 wt. %, ethane. In other embodiments, the feed stream may comprise at least 50 wt. % propane. In still other embodiments, the feed stream may comprise at least 50 wt. % n-butane. In additional embodiments, the feed stream may comprise at least 50 wt. % i-butane.

In one or more embodiments, a dehydrogenation reaction may utilize gallium and/or platinum catalyst as a catalyst. In such embodiments, the catalyst may comprise a gallium and/or platinum catalyst. For example, if the reaction is a dehydrogenation reaction, then the catalyst may comprise gallium and/or platinum catalyst. As described herein, a gallium and/or platinum catalyst comprises gallium, platinum, or both. The gallium and/or platinum catalyst may be carried by an alumina or alumina silica support, and may optionally comprise potassium. Such gallium and/or platinum catalysts are disclosed in U.S. Pat. No. 8,669,406, which is incorporated herein by reference in its entirety. However, it should be understood that other suitable catalysts may be utilized to perform the dehydrogenation reaction.

The reaction may also be a cracking reaction, a dehydration reaction, a methanol-to-olefin reaction, or other reaction. Further details of cracking reactions, dehydration reactions, and methanol-to-olefin reactions may be found in co-pending U.S. Provisional Patent Application Ser. No. 62/470,567, filed on Mar. 13, 2017, which is incorporated by reference herein in its entirety.

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, material 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.