Methods and systems for alkylate production involving multi-zone alkylation reactor

Abstract

The present invention provides methods and systems for alkylate production involving a multi-zone alkylation reactor. The multi-zone alkylation reactor includes a plurality of alkylation zones vertically spaced apart in a series configuration; and a partition separating the plurality of alkylation zones into at least two mechanically separated catalytic volumes.

Description

[0001] INVENTORS: Rajeev Ranjan and Anubhav Kapil

[0002] Cross Reference to Related Applications

[0003] This application claims priority to U.S. Patent Application having Serial No. 18 / 336,936, filed June 16, 2023, the contents of which are incorporated by reference in their entirety. TECHNICAL FIELD

[0004] The present disclosure relates to embodiments of multi-zone alkylation reactors and methods of their use in alkylate production systems. These systems and methods can increase the production of alkylates and can also reduce the amount of recycle stream or regen gas stream utilized to the alkylation reactor. BACKGROUND

[0005] Refinery operations have been struggling to meet high demand for higher octane fuels. Technologies such as KBR’s solid acid alkylation technology (K-SAAT™ technology) use isobutane solvent to convert olefins to alkylates in an alkylation reactor. The alkylation process uses fixed bed catalyst supported reactions to convert isoparaffin solvent and olefins to higher molecular weight paraffins. In a fixed bed reactor, the primary reaction of olefins with isoparaffins competes with the secondary reaction between olefins. The rate constant for the secondary olefin to olefin reaction is 2 orders of magnitude higher than the rate constant for the primary reaction. Therefore, the isobutane to olefin (I / O) ratio desirably remains high by at least two orders of magnitude. To maintain this relatively high I / O ratio, a large amount of alkylate containing stream from the alkylation reactor is recycled back to the alkylation reactor. However, this large amount of recycle and associated pressure drop reduces the amount of alkylate that can potentially be processed. SUMMARY

[0006] Systems and methods are provided herein that address these shortcomings of the prior art and provide other additional or alternative advantages. The disclosure herein provides several embodiments of multi-zone alkylation reactors and systems and methods for alkylate production.

[0007] One embodiment of the alkylation system includes a multi-zone alkylation reactor. The multi-zone alkylation reactor includes multiple alkylation zones vertically spaced in series. The multi-zone alkylation reactor includes at least one vertical baffle that divides the multiple alkylation zones into at least a first mechanically separated catalytic volume and a second mechanically separated catalytic volume. Additionally, the multi-zone alkylation reactor includes an isobutane inlet positioned to supply an isobutane stream to the first mechanically separated catalytic volume; and at least one olefin feed inlet positioned to supply an olefin-containing stream to the multiple alkylation zones, thereby generating an alkylated feed stream. The multi-zone alkylation reactor further includes a first alkylate product conduit for conveying the alkylated feed stream from the first mechanically separated catalytic volume to the second mechanically separated catalytic volume.

[0008] One embodiment of the alkylation system includes a multi-zone alkylation reactor with a recirculation pump. The multi-zone alkylation reactor includes multiple alkylation zones vertically spaced in series; vertical baffles dividing the multiple alkylation zones into two mechanically separated catalytic volumes; multiple olefin feed inlets positioned to supply an olefin-containing feed stream to each of the multiple alkylation zones in the two mechanically separated catalytic volumes; an isobutane inlet for supplying isobutane to a first alkylation zone in the first mechanically separated catalytic volume; a first plurality of conduits configured for fluid flow of the alkylation feed stream through the multiple alkylation zones in the first mechanically separated catalytic volume; a first alkylate product conduit for conveying the alkylation feed stream from the last alkylation zone in the first mechanically separated catalytic volume to the first alkylation zone in the second mechanically separated catalytic volume; a second plurality of conduits configured for fluid flow of the alkylation feed stream through the multiple alkylation zones in the second mechanically separated catalytic volume; and a second alkylate product conduit for conveying the alkylation feed stream from the last alkylation zone in the second mechanically separated catalytic volume to a recirculation pump. The fluid stream can flow downwards or upwards through multiple alkylation zones. The olefin-containing feed stream contains olefins (such as ethylene and propylene) and light components (such as hydrogen and methane). The alkylation feed stream contains alkylates produced by the reaction of olefins in the olefin-containing feed stream with isobutane. The alkylates comprise a mixture of high-octane branched alkanes. Each mechanically separated catalytic volume can be configured as a hydraulically sealed reaction chamber. Each of the multiple alkylation zones contains a solid acid alkylation catalyst. A recirculation pump is configured to receive the alkylation feed stream from a second alkylation product conduit, direct a first portion of the alkylation feed stream for further processing to produce an enriched alkylation product containing high-octane branched alkanes, and recirculate a second portion of the alkylation feed stream back to the first mechanically separated catalytic volume, thereby maintaining the desired isobutane to olefin ratio. In some embodiments, this ratio is in the range of about 300:1 to about 500:1. Compared to conventional alkylation reactor recirculation pumps, this recirculation pump can reduce flow rate by at least 50%.

[0009] Another embodiment of an alkylation system that increases alkylate products includes a multi-zone alkylation reactor and a recirculation pump. Some embodiments include a deisobutane tower in fluid communication with the recirculation pump. For example, the multi-zone alkylation reactor includes a plurality of alkylation zones vertically spaced in series; at least one vertical baffle dividing the plurality of alkylation zones into at least two mechanically separated catalytic volumes; a plurality of olefin feed inlets positioned to supply an olefin-containing feed stream to each of the plurality of alkylation zones in the at least two mechanically separated catalytic volumes; an isobutane inlet for supplying isobutane to a first alkylation zone in a first mechanically separated catalytic volume; a first plurality of conduits configured for fluid flow of the alkylation feed stream through the plurality of alkylation zones in the first mechanically separated catalytic volume; a first alkylate product conduit for conveying the alkylation feed stream from the last alkylation zone in the first mechanically separated catalytic volume to the first alkylation zone in a second mechanically separated catalytic volume; a second plurality of conduits configured for fluid flow of the alkylation feed stream through the plurality of alkylation zones in the second mechanically separated catalytic volume; and a second alkylate product conduit for conveying the alkylation feed stream from the last alkylation zone in the second mechanically separated catalytic volume to a recirculation pump. The alkylation feed stream contains alkylates produced by the reaction of olefins in an olefin-containing feed stream with isobutane. The fluid stream can flow downwards or upwards through multiple alkylation zones. A recirculation pump is configured to receive the alkylation feed stream from a second alkylate product conduit, direct a first portion of the alkylation feed stream to a deisobutane tower, and recycle a second portion of the alkylation feed stream to a first mechanically separated catalytic volume, thereby maintaining a desired molar ratio of isobutane to olefins. In some embodiments, this ratio is in the range of about 300:1 to about 500:1. The deisobutane tower is configured to receive the first portion of the alkylation feed stream from the recirculation pump and separate the first portion of the alkylation feed stream into (i) a recirculated isobutane feed stream to be supplied to the first mechanically separated catalytic volume; (ii) a n-butane feed stream; and (iii) a product feed stream containing a mixture of high-octane branched alkanes.

[0010] Examples include methods for producing alkylates involving a multi-zone alkylation reactor. For example, the multi-zone alkylation reactor may include two mechanically separated catalytic volumes, wherein a first plurality of alkylation zones and a second plurality of alkylation zones are loaded with alkylation catalysts; a first plurality of conduits configured for downward or upward fluid flow through the first plurality of alkylation zones in the first mechanically separated catalytic volume; and a second plurality of conduits configured for downward or upward fluid flow through a second plurality of alkylation zones in the second mechanically separated catalytic volume. One such method includes the steps of: (i) supplying an isobutane feed stream to a multi-zone alkylation reactor through an isobutane inlet; (ii) supplying an olefin-containing feed stream through a first plurality of olefin feed inlets located at each of a first plurality of alkylation zones in a first mechanically separated catalytic volume and through a second plurality of olefin feed inlets located at a second plurality of alkylation zones in a second mechanically separated catalytic volume; and (iii) guiding an alkylated feed stream containing alkylates produced by the reaction of the olefin-containing feed stream with isobutane in each of the first plurality of alkylation zones through a first plurality of conduits configured for downward fluid flow of the alkylated feed stream through the first mechanically separated catalytic volume. The method comprises: (iv) directing an alkylate feed stream from the last alkylation zone in a first mechanically separated catalytic volume through a first alkylate product conduit to the first alkylation zone in a second mechanically separated catalytic volume; (v) directing an alkylate feed stream from the first alkylation zone in the second mechanically separated catalytic volume through a second plurality of conduits configured for downward fluid flow of the alkylate feed stream through the second plurality of alkylation zones in the second mechanically separated catalytic volume; and (vi) directing an alkylate feed stream from the last alkylation zone in the second mechanically separated catalytic volume through the second alkylate product conduit to a recirculation pump. In some embodiments, the method may include the steps of: directing a first portion of the alkylate feed stream from the recirculation pump for further processing to produce an enriched alkylate product containing high-octane branched alkanes, and recycling a second portion of the alkylate feed stream back to the first mechanically separated catalytic volume to obtain a desired isobutane to olefin ratio. In some embodiments, this ratio is in the range of about 300:1 to about 500:1.

[0011] The embodiments include a method for regenerating alkylation zones in a multi-zone alkylation reactor. The multi-zone alkylation reactor includes two mechanically separated catalytic volumes, wherein a first alkylation zone and a second plurality of alkylation zones are loaded with spent alkylation catalyst; a first plurality of conduits configured for downward or upward fluid flow through the first plurality of alkylation zones in the first mechanically separated catalytic volume; and a second plurality of conduits configured for upward or downward fluid flow through the second plurality of alkylation zones in the second mechanically separated catalytic volume. One such method includes the following steps: (i) directing a regenerated feed stream to a compressor to produce a compressed regenerated feed stream; (ii) supplying the compressed regenerated feed stream to a heat exchanger positioned to allow cross-flow of the compressed regenerated feed stream with a waste regenerated feed stream from the outlet of a multi-zone alkylation reactor to produce a hot compressed regenerated feed stream and a cooled waste regenerated feed stream; (iii) directing the hot compressed regenerated feed stream from the heat exchanger to a heater to produce a regenerated feed stream; (iv) supplying the regenerated feed stream to the inlet of the multi-zone alkylation reactor; and (v) directing the regenerated feed stream through a first plurality of conduits in a first plurality of alkylation zones and a first mechanically separated catalytic volume, and through a second plurality of conduits in a second plurality of alkylation zones and a second mechanically separated catalytic volume, to promote interaction with the waste alkylation catalyst in the first plurality of alkylation zones and the second plurality of alkylation zones under catalyst regeneration conditions to regenerate the waste alkylation catalyst and produce a regenerated catalyst with significantly enhanced alkylation activity and a waste regenerated feed stream exiting at the outlet of the multi-zone alkylation reactor. In some embodiments, the method may further include the steps of: supplying a waste regenerated feed stream from the outlet of the multi-zone alkylation reactor to a heat exchanger, and directing the waste regenerated feed stream from the heat exchanger to a gas-liquid separator to separate the waste material from the cooled waste regenerated feed stream, thereby producing a regenerated feed stream and a waste material feed stream containing soluble and insoluble coke. In some embodiments, the regenerated feed stream contains a hydrogen-rich gas. The hydrogen-rich gas may contain 70 to 90 weight percent (wt%) of hydrogen. In some embodiments, the heater is a flame heater. Attached Figure Description

[0012] These embodiments and other features, aspects, and advantages of this disclosure will be better understood in conjunction with the following description, claims, and accompanying drawings. However, it should be noted that the drawings illustrate only certain embodiments of this disclosure and should therefore not be considered as limiting the scope of this disclosure.

[0013] Figure 1 This is a schematic diagram of a multi-zone alkylation system according to an embodiment of the present disclosure.

[0014] Figure 2 This is a schematic diagram of a multi-zone alkylation system with a deisobutane tower according to an embodiment of the present disclosure.

[0015] Figure 3 This is a schematic representation of an alkylation system according to an embodiment of the present disclosure, the alkylation system including a multi-zone alkylation reactor coupled to a number of components, including a heat exchanger, a cooler, a flash tank, a compressor, and a heater.

[0016] Figure 4 This is a schematic diagram of a multi-zone alkylation system according to an embodiment of the present disclosure. Detailed Implementation

[0017] This disclosure provides multi-zone alkylation systems and methods for producing alkylates using these systems. To provide a more detailed understanding of the features and advantages of embodiments of the methods and systems disclosed herein, as well as other features and advantages that will become apparent, a more specific description of non-limiting embodiments of the methods and systems is provided. Numerous details are set forth in the following description to provide a thorough understanding of the various embodiments. In other instances, well-known processes, apparatus, and systems may not be described in particular detail to avoid unnecessarily obscuring the various embodiments. Additionally, certain features or details may be omitted from the description of the various embodiments to avoid obscuring them.

[0018] Alkylation reactors can be used to facilitate the processing of light olefins into high-quality, low Red vapor pressure (RVP) alkylates. One embodiment of an alkylation system includes a multi-zone alkylation reactor. The multi-zone alkylation reactor includes multiple alkylation zones vertically spaced in series. The multi-zone alkylation reactor includes at least one baffle that divides the multiple alkylation zones into at least a first mechanically separated catalytic volume and a second mechanically separated catalytic volume. In some embodiments, the baffle may be a vertical baffle or a horizontal baffle. The multi-zone alkylation reactor also includes an isobutane inlet positioned to supply an isobutane feed stream to the first mechanically separated catalytic volume; and at least one olefin feed inlet positioned to supply an olefin-containing feed stream to the multiple alkylation zones. The isobutane and olefin feeds react under catalytic alkylation conditions to produce an alkylated feed stream. The multi-zone alkylation reactor further includes a first alkylate product conduit to convey the alkylated feed stream from the first mechanically separated catalytic volume to the second mechanically separated catalytic volume. The alkylation feed stream comprises alkylation products as well as unreacted isobutane and olefins. The alkylation feed stream may continue in a first fluid flow direction until it reaches the last alkylation zone in a first mechanically separated catalytic volume. The alkylation feed stream can then be directed from the last alkylation zone in the first mechanically separated catalytic volume to a first alkylation zone in a second mechanically separated catalytic volume via a first alkylation product conduit. This alkylation feed stream may be directed in a second fluid flow direction to the last alkylation zone in the second mechanically separated catalytic volume. In some embodiments, both the first and second fluid flow directions are downward. In some embodiments, the first fluid flow direction is downward and the second fluid flow direction is upward. In some embodiments, the first fluid flow direction is upward and the second fluid flow direction is downward. In some embodiments, both the first and second fluid flow directions are upward. In some embodiments, the first and second fluid flow directions in the corresponding mechanically separated catalytic volumes may include left-hand flow, right-hand flow, or a combination thereof. In some embodiments, two or more vertically or horizontally positioned partitions may be configured to divide a plurality of alkylation sites into at least two or more mechanically separated catalytic volumes.

[0019] One embodiment of an alkylation system includes a multi-zone alkylation reactor. The multi-zone alkylation reactor may include a plurality of alkylation zones vertically spaced in series; and at least one vertical baffle dividing the plurality of alkylation zones into at least two mechanically separated catalytic volumes. The multi-zone alkylation reactor may include a plurality of olefin feed inlets positioned to supply an olefin-containing feed stream to each of the plurality of alkylation zones in the at least two mechanically separated catalytic volumes. The multi-zone alkylation reactor may also include an isobutane inlet for supplying isobutane to a first alkylation zone in a first mechanically separated catalytic volume. The multi-zone alkylation reactor may further include a first plurality of conduits configured to allow the alkylation feed stream to flow fluidly through the plurality of alkylation zones in the first mechanically separated catalytic volume. In some embodiments, the first alkylate product conduit of the multi-zone alkylation reactor may convey the alkylation feed stream from the last alkylation zone in the first mechanically separated catalytic volume to the first alkylation zone in a second mechanically separated catalytic volume. A multi-zone alkylation reactor may include a second plurality of conduits configured for fluid flow of alkylation feed streams through multiple alkylation zones in a second mechanically separated catalytic volume. The fluid flow may be downward or upward through the multiple alkylation zones. Additionally, a second alkylate product conduit of the multi-zone alkylation reactor may deliver the alkylation feed stream out of the last alkylation zone in the second mechanically separated catalytic volume. In some embodiments, the alkylation feed stream is then directed to a recirculation pump. In embodiments having more than one vertical baffle, a third alkylate product conduit may deliver the alkylation feed stream from the last alkylation zone in the second mechanically separated catalytic volume to a first alkylation zone in a third mechanically separated catalytic volume. Embodiments of the multi-zone alkylation reactor may be configured to include three catalytic volumes separated by two vertical baffles, four catalytic volumes separated by three vertical baffles, etc. Furthermore, although sometimes described with reference to downward fluid flow of the alkylation feed stream through the alkylation zones, the multi-zone alkylation reactor may be designed for upward fluid flow in all or some of the mechanically separated catalytic zones.

[0020] The olefin-containing feed stream may contain olefins (such as ethylene and propylene) and light components (such as hydrogen and methane). The alkylation feed stream may contain alkylates produced by the reaction of olefins in the olefin-containing feed stream with isobutane. Alkylates include mixtures of high-octane branched alkanes. As mentioned herein, high-octane hydrocarbons have an octane number equal to or greater than a predetermined threshold (such as 90). For example, high-octane hydrocarbons may include branched isomers of octane, such as 2,2,4-trimethylpentane (isooctane) and 2,2,3-trimethylpentane, as well as other trimethyl isomers of C8+ hydrocarbons. Each mechanically separated catalytic volume in the mechanically separated catalytic volumes may be configured as a hydraulically sealed reaction chamber. Each of the multiple alkylation zones may contain a solid acid alkylation catalyst.

[0021] In some embodiments, the recirculation pump can be configured to receive an alkylate feed stream from a second alkylate product conduit and direct a portion of the alkylate feed stream for further processing to produce an enriched alkylate product containing high-octane alkanes. In some embodiments, the recirculation pump can be configured to recycle a second portion of the alkylate feed stream to a first mechanically separated catalytic volume. Therefore, the recirculation pump can maintain a desired isobutane to olefin ratio in a multi-zone alkylation reactor. In some embodiments, this ratio can be in the range of about 300:1 to about 500:1, or about 350:1 to about 500:1, or about 400:1 to about 500:1, or about 300:1 to about 450:1, or about 300:1 to about 400:1. In some embodiments, the flow rate of the recirculation pump can be reduced by at least 50% compared to a conventional alkylation reactor recirculation pump. In some embodiments, the flow rate of the recirculation pump can be reduced by at least 30% or 40% compared to a conventional alkylation reactor recirculation pump. In some embodiments, the recirculation pump flow rate can be reduced by at least 60% compared to a conventional alkylation reactor recirculation pump. In some embodiments, the reduced recirculation flow rate can correspond to reduced operating costs without compromising product yield.

[0022] Figure 1This is a schematic diagram of a multi-zone alkylation reactor according to embodiments of the present disclosure. In some embodiments, the alkylation system 100 includes a multi-zone alkylation reactor 102. The multi-zone alkylation reactor 102 includes a shell 103 or a housing. The multi-zone alkylation reactor 102 includes a plurality of alkylation zones 120, such as alkylation zones 120A, 120B, 120C, 120D, 120E, 120F, 120G, 120H, 120I, and 120J, which are defined within the shell 103. Alkylation zones 120A, 120B, 120C, 120D, and 120E are vertically spaced in series. Alkylation zones 120F, 120G, 120H, 120I, and 120J are vertically spaced in series. At least one vertical partition 104 separates the plurality of alkylation zones 120 into at least two mechanically separated catalytic volumes 105. In the illustrated embodiments, alkylation zones 120A, 120B, 120C, 120D, and 120E are defined within a first mechanically separated catalytic volume 105A, and alkylation zones 120F, 120G, 120H, 120I, and 120J are defined within a second mechanically separated catalytic volume 105B. The vertical partition 104 may be a solid plate extending vertically within the housing 103. In some embodiments, the plate may be made of metal or an inert material. For example, in some embodiments, the vertical partition extends in a plane defined from an upper inner surface to a lower inner surface of the housing 103, and from a first transverse inner surface of the housing 103 to an opposing second transverse inner surface. In some embodiments, the vertical partition 104 may be welded or non-removably coupled to a suitable portion of the housing 103 of the multi-zone alkylation reactor 102. In other embodiments, the vertical partition 104 may be removable and attached to the housing 103 using partition support attachments. Although shown as having a single vertical partition 104, two or more vertical partitions 104 may be implemented in a multi-zone alkylation reactor 102 based on various operational factors, such as physical space availability, easy accessibility of internal components, and / or target product quality. Furthermore, although shown as having 10 alkylation zones 120, the multi-zone alkylation reactor 102 can be designed to include any suitable number of alkylation zones 120, such as 2, 4, 6, 8, 12, 14, or more. The vertical partition 104 of this disclosure effectively increases the number of conventional alkylation stages, thereby increasing the number of alkylation zones 120, through multiple vertical partitions 104.

[0023] Multiple olefin feed inlets 114, such as olefin feed inlets 114A, 114B, 114C, 114D, 114E, 114F, 114G, 114H, 114I and 114J, are positioned to supply an olefin-containing feed stream 110 through the housing 103 and to each of the multiple alkylation zones 120 within two mechanically separated catalytic volumes 105. For example, each of the olefin-containing feed streams 110A, 110B, 110C, 110D, 110E, 110F, 110G, 110H, 110I, and 110J can be received by the corresponding alkylation zone among the alkylation zones 120A, 120B, 120C, 120D, 120E, 120F, 120G, 120H, 120I, and 120J via the corresponding olefin feed inlets 114A, 114B, 114C, 114D, 114E, 114F, 114G, 114H, 114I, and 114J. In some embodiments, the olefin-containing feed stream 110 comprises olefins (such as ethylene and propylene) and light components (such as hydrogen and methane). In the illustrated embodiment, isobutane stream 112 is provided and supplied through an inlet defined in the shell 103 to a first alkylation zone 120A in a first mechanically separated catalytic volume 105A. In some embodiments, a portion of the isobutane is also premixed with an olefin feed stream 110 supplied to an olefin feed inlet 114. Each of the mechanically separated reaction volumes 105A and 105B can be configured as a hydraulically sealed reaction chamber. For a given nominal length of the shell 103, two mechanically separated catalytic volumes 105 having alkylation zones 120 vertically spaced in a series configuration can increase the total fluid flow length of the multi-zone alkylation reactor 102 available for alkylation reactions. Furthermore, the mechanically separated catalytic volumes 105 can also increase the number of multiple olefin feed inlets 114 of the multi-zone alkylation reactor 102 compared to previously implemented reactors. In some embodiments, the multi-zone alkylation reactor 102 is configured to allow the rate of the primary reaction of olefins with isoparaffins to be maintained at least two orders of magnitude higher than the rate of the secondary reaction between olefins. In some embodiments, this configuration of the multi-zone alkylation reactor 102 allows for the maintenance of an optimal I / O ratio. As discussed below, each alkylation zone 120 contains an alkylation catalyst suitable for producing alkylates. In some embodiments, reactor conditions may generally be similar to those of previously implemented alkylation reactors, such as the K-SAAT reactor. In some embodiments, the alkylation reaction is carried out at pressures ranging from 200 psi (g) to 300 psi (g) and temperatures ranging from 43°C to 82°C.

[0024] According to some embodiments, each of the plurality of alkylation zones 120 comprises a solid acid alkylation catalyst, such as a K-SAAT™ catalyst (KBR, Houston, Tex.). Aspects of solid acid catalyst alkylation are described, for example, in U.S. Patent Nos. 9,079,815 and 10,179,753 and U.S. Patent Publication No. 2020 / 0031733, which are incorporated herein by reference. The alkylation reaction between isobutane and olefins (such as those contained in the olefin-containing feed stream 110) can be carried out on a solid acid catalyst in a fixed bed in the alkylation zone 120. Indeed, each alkylation zone 120 of this embodiment is shown having a corresponding fixed bed therein. The solid acid catalyst may be a zeolite catalyst, as described in the referenced patent, and may contain metals such as platinum, palladium, and / or nickel.

[0025] In this embodiment, the multi-zone alkylation reactor 102 includes a plurality of conduits 106 (e.g., flow channels, distribution plates) to guide fluid flows of reactants and products as part of an alkylation feed stream through at least a portion of a plurality of alkylation zones 120. In some embodiments, the conduits 106 interconnect the alkylation zones 120 within respective mechanically separated catalytic volumes 105. For example, within a first mechanically separated catalytic volume 105A, the alkylation feed stream within alkylation zone 120A may sequentially flow through conduits 106A, alkylation zone 120B, alkylation zone 120C, alkylation zone 120D, alkylation zone 120E. As described above, isobutane in the alkylation feed stream within each of these alkylation zones 120 may react with olefins in a corresponding olefin-containing feed stream 110. In addition to unreacted olefins and isobutane, the alkylation feed stream also contains alkylates produced by the reaction of olefins in the olefin-containing feed stream with isobutane from the isobutane feed stream 112. Alkylates comprise a mixture of high-octane branched alkanes. As used herein, high octane refers to a hydrocarbon or mixture thereof having an octane number equal to or greater than a predetermined threshold. For example, high-octane hydrocarbons in some embodiments have an octane number of 90 or greater. Obtaining valuable high-octane fuels involves a primary reaction between isobutane and butene to produce isooctane. As described herein, alkylation system 100 produces alkylates with low RVP, which further increases the alkylate yield. In multi-zone alkylation reactor 102, isobutane and butene are alkylated to produce isooctane and n-butane. Subsequent fractionation can crack the alkylation feed stream via two reactions. In the first reaction, isooctane can be cracked into isopentane and propylene. In the second reaction, isobutane and propylene can be cracked into isoheptane.

[0026] In the illustrated embodiment, a first alkylate product conduit 117 is positioned to deliver an alkylate feed stream from the last alkylation zone 120E (or the bottommost alkylation zone) in a first mechanically separated catalytic volume 105A to a first alkylation zone 120F (or the topmost alkylation zone) in a second mechanically separated catalytic volume 105B. A plurality of conduits 106 guide the fluid flow of the alkylate feed stream through alkylation zones 120 in the second mechanically separated catalytic volume 105B. For example, the alkylate feed stream within alkylation zone 120F may flow sequentially through conduit 106F, alkylation zone 120G, conduit 106G, alkylation zone 120H, conduit 106H, alkylation zone 120I, conduit 106I, and alkylation zone 120J. As discussed above, isobutane in the alkylate feed stream within each of these alkylation zones 120 may react with a corresponding olefin-containing feed stream in the olefin-containing feed stream 110.

[0027] In some embodiments, the second alkylate product conduit 118 can deliver an alkylate feed stream from the last alkylation zone 120J (or the bottommost alkylation zone) in the second mechanically separated catalytic volume 105B to a recirculation pump 108 of the alkylation system 100. The recirculation pump 108 can be any suitable fluid movement device for receiving the alkylate feed stream from the second alkylate product conduit 118. Thus, the alkylation system 100 can produce a first portion 119 of the alkylate feed stream as a product or intermediate and recirculate a second portion 116 of the alkylate feed stream back to the first mechanically separated catalytic volume 105A to maintain a desired or target ratio of isobutane to olefins therein. In some embodiments, the target isobutane to olefin ratio ranges from about 300:1 to about 500:1. In some embodiments, the target isobutane to olefin ratio is about 400:1. As used herein, a threshold or high isobutane to olefin ratio refers to a ratio of about 300:1 or higher.

[0028] In some embodiments, the amount of alkylate recycled to the multi-zone alkylation reactor 102 is calculated to minimize macro- and micro-mixing properties. The alkylation system 100 disclosed in this invention, having one or more vertical baffles 104, provides a significant reduction of 50% or more in the amount of alkylate feedstock recycled back to the multi-zone alkylation reactor 102 compared to systems without vertical baffles.

[0029] Furthermore, the addition of vertical baffles 104 can reduce the cross-sectional area of ​​each alkylation zone 120 compared to an alkylation reactor without baffles. In this embodiment, the length of the alkylation zones 120 (e.g., reaction length, zone height) can be kept constant. Each mechanically separated catalytic volume 105 can have a balanced distribution of a corresponding olefin-containing feed stream 110 and an isobutane feed stream 112 across the alkylation zones 120. Although shown as including downward fluid flow through each mechanically separated catalytic volume 105, other embodiments of this disclosure may alternatively provide upward fluid flow through one, more than one, or all of the mechanically separated catalytic volumes 105. As used herein, a downward flow direction can generally refer to a flow direction corresponding to or parallel to gravity, and an upward flow direction can generally refer to a flow direction opposite to gravity. Furthermore, some embodiments of this disclosure may include a design of a multi-zone alkylation reactor 102 in which the shell 103 generally extends horizontally, rather than as shown Figure 1 The vertical baffle 104 is typically vertically extended. In such embodiments, the vertical baffle 104 can be adjusted to a horizontal baffle, which facilitates leftward, rightward, or a combination thereof flow in the corresponding mechanically separated catalytic volume 105.

[0030] In some embodiments, the solid acid alkylation catalyst of alkylation zone 120 may comprise a zeolite material supported on a non-precious metal. An example of a suitable catalyst is KBR's ExSact™ catalyst, a zeolite-based catalyst that exhibits selectivity for high-octane TMPs and eliminates acid-soluble oils. A suitable catalyst may have improved mass transfer to prevent pore blockage, facilitate alkylation in the polymerization reaction, and exhibit high selectivity for 2,3,3-trimethylpentane and 2,3,4-trimethylpentane with minimal isomerization from trimethylpentane to dimethylhexane. In some embodiments, the alkylation reaction within the multi-zone alkylation reactor 102 is carried out at low temperatures (e.g., 40°C–80°C), is slightly exothermic, and provides a radial temperature profile or distribution within about 2.8 or 3°C. In this embodiment, the mechanically separated catalytic volume 105 can reduce both macroscopic and microscopic mixing properties within the multi-zone alkylation reactor 102. The reduced macro- and micro-mixing properties include minimizing the mixing volume in the multi-zone alkylation reactor 102 and reducing the amount of spare mix supplied to the multi-zone alkylation reactor 102, as well as reducing a portion 116 of the alkylation material stream that is recirculated back to the multi-zone alkylation reactor 102 via the recirculation pump 108.

[0031] The isobutane to olefin ratio typically controls the alkylate concentration within the multi-zone alkylation reactor 102. At target or high isobutane to olefin ratios of 300:1 or higher, the multi-zone alkylation reactor 102 can produce high-octane alkylates. Furthermore, a higher isobutane to olefin ratio can improve catalyst lifetime. In this embodiment, the flow rate of the alkylation reactor recirculation pump 108 can be reduced by at least 50% compared to the recirculation pump in a conventional alkylation system. The reduced flow rate of the recirculation pump 108 can increase the amount of alkylate feedstock that can be further processed.

[0032] The embodiments also include methods for increasing alkylate yield and reducing recycle streams to a multi-zone alkylation reactor. One such method for reducing recycle to a multi-zone alkylation reactor may involve directing an isobutane feed stream to multiple alkylation zones in the multi-zone alkylation reactor. The multi-zone alkylation reactor may include at least one vertical baffle that separates the multiple alkylation zones into at least two mechanically separated catalytic volumes. An olefin-containing feed stream may be directed to each of the two or more mechanically separated catalytic volumes via multiple olefin feed inlets. Isobutane may be supplied to a first alkylation zone in a first mechanically separated catalytic volume via an isobutane inlet. In one embodiment, isobutane may react with olefins at the first alkylation zone in the first mechanically separated catalytic volume to produce an alkylate feed stream. Thus, the amount of alkylates in the alkylate feed stream may increase as isobutane and each olefin-containing feed stream react in their respective alkylation zones, continuing until the last alkylation zone in the first mechanically separated catalytic volume. The alkylation feed stream can then be directed from the last alkylation zone in the first mechanically separated catalytic volume to the first alkylation zone in the second mechanically separated catalytic volume via a first alkylate product conduit. The alkylation feed stream can be directed from the first alkylation zone in the second mechanically separated catalytic volume to continue the alkylation reaction between isobutane and each olefin-containing feed stream supplied to the alkylation zone in the second mechanically separated catalytic volume. This alkylation feed stream can be directed to the last alkylation zone in the second mechanically separated catalytic volume to increase the amount of alkylates therein. The alkylation feed stream can then be directed from the last alkylation zone in the second mechanically separated catalytic volume to a recirculation pump. The alkylation feed stream exiting the recirculation pump can be separated into a first portion and a second portion. The first portion of the alkylation feed stream can be directed from the recirculation pump to be further processed to produce an enriched alkylate product containing high-octane branched alkanes. The second portion of the alkylation feed stream can be directed from the recirculation pump to the first alkylation zone in the first mechanically separated catalytic volume to maintain the desired isobutane to olefin ratio. In some embodiments, the ratio is in the range of about 300:1 to about 500:1.

[0033] Figure 2This is a schematic diagram of a multi-zone alkylation system 200 with a deisobutane tower according to embodiments of the present disclosure. In some embodiments, the alkylation production system 200 includes a multi-zone alkylation reactor 102. Figure 2 The multi-zone alkylation reactor 102 can typically correspond to Figure 1 The multi-zone alkylation reactor 102, wherein the corresponding elements can be described with reference to their operation in the alkylate production system 200. For example, the multi-zone alkylation reactor 102 of this embodiment includes a plurality of alkylation zones 120, such as alkylation zones 120A, 120B, 120C, 120D, 120E, 120F, 120G, 120H, 120I, and 120J, which can be defined within a shell 103 and vertically spaced apart in a series configuration. At least one vertical partition 104 separates the plurality of alkylation zones 120 into at least two mechanically separated catalytic volumes 105A and 105B. Multiple olefin feed inlets 114, such as olefin feed inlets 114A, 114B, 114C, 114D, 114E, 114F, 114G, 114H, 114I, and 114J, can be positioned to supply an olefin-containing feed stream 110 to each of a plurality of alkylation zones 120 in two mechanically separated catalytic volumes 105A and 105B. An isobutane feed stream 112 is supplied to a first alkylation zone 120A in the first mechanically separated catalytic volume 105A. In this embodiment, the multi-zone alkylation reactor 102 includes a plurality of conduits 106 to guide the fluid flow of the alkylation feed stream through at least a portion of the plurality of alkylation zones 120. For example, the alkylation material flow within alkylation zone 120A can sequentially flow through conduit 106A, alkylation zone 120B, conduit 106B, alkylation zone 120C, conduit 106C, alkylation zone 120D, conduit 106D, and alkylation zone 120E. The first plurality of conduits 106A, 106B, 106C, and 106D can be configured to provide a downward fluid flow of alkylation material from alkylation zone 120A through alkylation zones 120B, 120C, 120D, and 120E in a first mechanically separated catalytic volume 105A.

[0034] The first alkylate product conduit 117 can transport the alkylate feed stream from the last alkylation zone 120E in the first mechanically separated catalytic volume 105A to the first alkylation zone 120F in the second mechanically separated catalytic volume 105B. A second plurality of conduits 106F, 106G, 106H, and 106I can be configured to provide a downward fluid flow of the alkylate feed stream from alkylation zone 120F through alkylation zones 120G, 120H, 120I, and 120J in the second mechanically separated catalytic volume 105B. For example, the alkylate feed stream within alkylation zone 120F can sequentially flow through conduit 106F, alkylation zone 120G, conduit 106G, alkylation zone 120H, conduit 106H, alkylation zone 120I, conduit 106I, and alkylation zone 120J. The second alkylate product conduit 118 can deliver the alkylate feed stream from the last alkylation zone 120J in the second mechanically separated catalytic volume 105B to the recirculation pump 108. The recirculation pump 108 of the alkylation production system 200 is configured to receive the alkylate feed stream from the second alkylate product conduit 118 and recirculate a first portion 119 of the alkylate feed stream from the recirculation pump 108 to the deisobutanizer 216. The alkylation production system 200 can also directly recirculate a second portion 116 of the alkylate feed stream back to the first mechanically separated catalytic volume 105A to maintain a desired or target ratio of isobutane to olefins. In some embodiments, the target isobutane to olefin ratio ranges from about 300:1 to about 500:1. In some embodiments, the target isobutane to olefin ratio is about 400:1. As used herein, a threshold or high isobutane to olefin ratio refers to a ratio of about 300:1 or higher.

[0035] The isobutane removal column 216 of the alkylation production system 200 is configured to receive a first portion 119 of the alkylation feed stream from the recirculation pump 108 and separate the first portion 119 of the alkylation feed stream into (i) a recirculating isobutane feed stream 222 supplied to a first mechanical separation catalytic volume 105A, (ii) a n-butane or n-butane feed stream 218, and (iii) a product feed stream 220 containing a mixture of high-octane branched alkanes. As used herein, a high-octane component refers to a hydrocarbon or mixture thereof having an octane number equal to or greater than a predetermined threshold, such as 90 or higher. The recirculating isobutane feed stream 222 may be enriched with isobutane and may be considered as a side fraction to be recycled to the multi-zone alkylation reactor 102 for further alkylation production. As is currently recognized, alkylation production systems 200 with one or more vertical partitions 104 provide a significant reduction of 50% or more in the amount of alkylates recycled back to the multi-zone alkylation reactor 102 compared to systems without vertical partitions.

[0036] Another embodiment of the method for increasing alkylate yield and reducing recycle flow to a multi-zone alkylation reactor involves including an isobutane removal tower in the alkylation system. An olefin-containing feed stream can be directed via multiple olefin feed inlets to each alkylation zone in two or more mechanically separated catalytic volumes of the multi-zone alkylation reactor. Isobutane can be supplied via an isobutane inlet. Isobutane can begin to interact with the olefin-containing feed stream at a first alkylation zone in a first mechanically separated catalytic volume to produce an alkylated feed stream. Therefore, the alkylated feed stream can continue to produce alkylates comprising the product of the reaction of isobutane and olefins from each olefin-containing feed stream in each alkylation zone. The alkylated feed stream can continue in a first fluid flow direction until it reaches the last alkylation zone in the first mechanically separated catalytic volume. The alkylated feed stream can then be directed from the last alkylation zone in the first mechanically separated catalytic volume to the first alkylation zone in a second mechanically separated catalytic volume via a first alkylate product conduit. The alkylation feed stream may include alkylates produced in each alkylation zone by the reaction of isobutane with olefins from each olefin-containing feed stream. This alkylation feed stream may be directed in a second fluid flow direction to the last alkylation zone in a second mechanically separated catalytic volume. In some embodiments, both the first and second fluid flow directions are downward. In some embodiments, the first fluid flow direction is downward and the second fluid flow direction is upward. In some embodiments, the first fluid flow direction is upward and the second fluid flow direction is downward. In some embodiments, both the first and second fluid flow directions are upward. The alkylation feed stream can then be directed from the last alkylation zone in the second mechanically separated catalytic volume to a recirculation pump. The recirculation pump may be configured to recirculate a first portion of the alkylation feed stream from the recirculation pump to a deisobutane tower and a second portion of the alkylation feed stream to the first mechanically separated catalytic volume to maintain a desired isobutane to olefin ratio. In some embodiments, this ratio is in the range of about 300:1 to about 500:1. A first portion of the alkylation feed stream can be directed from a recirculation pump to a deisobutane tower in certain embodiments to separate the first portion of the alkylation feed stream into (i) a recirculated isobutane feed stream supplied to a first mechanically separated catalytic volume; (ii) a n-butane feed stream; and (iii) a product feed stream containing a mixture of high-octane branched alkanes. The recirculated isobutane feed stream can then be directed to a first alkylation zone in the first mechanically separated catalytic volume for alkylation with the isobutane inlet feed stream and each olefin-containing feed stream.

[0037] Although Figure 1 and Figure 2This description pertains to a single multi-zone alkylation reactor, but embodiments of the alkylation system may include two, three, or more such reactors. For example, two or more multi-zone alkylation reactors may be arranged and connected in parallel with each other. In some embodiments, a single inlet stream may be diverted and supplied to each multi-zone alkylation reactor before or after merging with recycled isobutane. Furthermore, in some embodiments, an outlet stream may be received from each multi-zone alkylation reactor and merged before or after diverting an isobutane-rich stream from the outlet stream. In some embodiments, each reactor may operate with a 24-hour cycle length, and the feed isobutane to olefin ratio may be in the range of about 5 mol / mol to about 10 mol / mol, which may be measured before the feed stream is supplied to two or more multi-zone alkylation reactors. As discussed above, the bed isobutane to olefin ratio may be in the range of 300 mol / mol to 500 mol / mol. Alkylation reaction conditions may include temperatures of about 40°C to 80°C and pressures of about 232 psi(g) to 363 psi(g). This temperature range is advantageously favorable for alkylation compared to polymerization.

[0038] Examples may also include methods for regenerating alkylation zones in a multi-zone alkylation reactor. In one such embodiment, the multi-zone alkylation reactor includes two mechanically separated catalytic volumes having first and second plurality of alkylation zones, which may be loaded with spent alkylation catalyst. The multi-zone alkylation reactor may include a first plurality of conduits configured for fluid flow in the first mechanically separated catalytic volume and a second plurality of conduits configured for fluid flow in the second mechanically separated catalytic volume. As described above, the fluid flow through the first plurality of alkylation zones in the first mechanically separated catalytic volume may be provided in an upward or downward direction. Similarly, the fluid flow through the second plurality of alkylation zones in the second mechanically separated catalytic volume may be provided in an upward or downward direction. One such method may include (i) directing the regenerated feed stream to a compressor to produce a compressed regenerated feed stream. In some embodiments, the regenerated feed stream contains hydrogen-rich gas. The hydrogen-rich gas may contain about 60% to about 90% by weight, or about 70% to about 90% by weight, or about 75% to about 85% by weight, or about 70% by weight, or about 80% by weight of hydrogen. In some embodiments, the regenerated feed stream may contain other components, such as helium or ozone or oxygen. The method may further include (ii) supplying the compressed regenerated feed stream to a heat exchanger positioned such that the compressed regenerated feed stream cross-flows with a waste regenerated stream from the outlet of the multi-zone alkylation reactor to produce a hot compressed regenerated feed stream and a cooled waste regenerated feed stream. The method may further include (iii) directing the hot compressed regenerated feed stream from the heat exchanger to a heater to produce a regenerated feed stream. In some embodiments, the heater is a flame heater. Additionally, the method may further include (iv) supplying a regenerated feed stream to the inlet of a multi-zone alkylation reactor and (v) guiding the regenerated feed stream through a first plurality of alkylation zones in a first mechanically separated catalytic volume and through a second plurality of alkylation zones in a second mechanically separated catalytic volume. This flow can facilitate interaction with the spent alkylation catalyst in the first and second plurality of alkylation zones under catalyst regeneration conditions to regenerate the spent alkylation catalyst. This flow can additionally produce a regenerated catalyst with significantly increased alkylation activity and a spent regenerated feed stream exiting at the outlet of the multi-zone alkylation reactor. The term “substantially” means an increase in activity of the spent catalyst composition of at least about 50% by weight, or at least about 60% by weight, or at least about 70% by weight, or at least about 80% by weight, or at least about 90% by weight, or at least about 95% by weight, or at least about 97% by weight, or at least about 99% by weight or higher. In some embodiments, the regenerated catalyst may have activity similar to that of the fresh catalyst. The method may further include (vi) supplying the waste recycled material stream from the outlet of the multi-zone alkylation reactor to a heat exchanger and (vii) guiding the waste recycled material stream from the heat exchanger to a gas-liquid separator.A gas-liquid separator can separate the waste material from a cooled waste regeneration stream to produce a regeneration stream and a waste material stream. In some embodiments, catalyst regeneration conditions may include temperatures up to 275°C and pressures of approximately 290 psi (g).

[0039] Figure 3This is a schematic representation of an embodiment of an alkylation system 300, which includes a multi-zone alkylation reactor 102 coupled to several components. According to one embodiment of this disclosure, these components may include one or more of a heat exchanger, cooler, flash tank, compressor, and / or heater constituting a regeneration system. In the illustrated embodiment, the alkylation system 300 includes a compressor 322, a heat exchanger 324, a cooler 326, a gas-liquid separator 328, and a heater 330. In some embodiments, the heater is a flame heater. These and / or other suitable components may be used to regenerate one or more alkylation zones 120 of the multi-zone alkylation reactor 102. In this embodiment, the compressor 322 receives a regeneration stream 312. The compressor 322 is configured to compress the regeneration stream 312 to produce a compressed regeneration stream 310 using a suitable compression device. In some embodiments, the regeneration stream 312 contains about 60% by weight to about 90% by weight of hydrogen. In some embodiments, the regeneration pressure of the compressed regeneration stream 310 may be based on the purity of the regeneration gas. In some embodiments, the regeneration pressure can be selected to meet a minimum or target H2 partial pressure threshold at the reactor outlet, such as approximately 150 psi(g)–180 psi(g), to achieve efficient regeneration operation. Heat exchanger 324 can receive compressed regenerated feed stream 310 from compressor 322. In this embodiment, heat exchanger 324 can be configured to allow cross-flow of the compressed regenerated feed stream 310 with the waste regenerated feed stream 336 from the outlet of the multi-zone alkylation reactor 102, thereby producing a hot compressed regenerated feed stream 316 and a cooled waste regenerated feed stream 304. In other embodiments, heat exchanger 324 can achieve counter-current or parallel flow between the compressed regenerated feed stream 310 and the waste regenerated feed stream 336. Heater 330 can receive the hot compressed regenerated feed stream 316 from heat exchanger 324 and heat the hot compressed regenerated feed stream 316 to produce a regeneration feed stream 318. In some embodiments, the regeneration feed stream 318 is heated to 275°C. In some embodiments, the heater is a flame heater. In the illustrated embodiment, the first inlet 332 of the multi-zone alkylation reactor 102 receives a regeneration feed stream 318. The multi-zone alkylation reactor 102 may include two or more mechanically separated catalytic volumes 105 separated by one or more vertical baffles 104. The mechanically separated catalytic volumes 105 may include a first plurality of alkylation zones (120A, 120B, 120C, 120D, and 120E) and a second plurality of alkylation zones (120F, 120G, 120H, 120I, and 120J) loaded with spent alkylation catalyst. The first plurality of conduits 106A, 106B, 106C, and 106D are configured for the regeneration feed stream 318 to flow downwards from alkylation zone 120A through alkylation zones 120B, 120C, 120D, and 120E in the first mechanically separated catalytic volumes 105A.In some embodiments, the regenerated feed stream 318 interacts with the spent alkylation catalyst in the first plurality of alkylation zones under catalyst regeneration conditions. This interaction can regenerate the spent alkylation catalyst and produce a regenerated catalyst with significantly improved alkylation activity. During regeneration within the multi-zone alkylation reactor 102, soft coke deposited on the catalyst can be removed via the regenerated feed stream 318.

[0040] A first alkylate product conduit 117 is configured to receive a regeneration feed stream 318 from the last alkylation zone 120E in a first mechanically separated catalytic volume 105A and to direct the regeneration feed stream 318 to a second inlet 334 of a multi-zone alkylation reactor 102. A first alkylation zone 120F in a second mechanically separated catalytic volume 105B can receive the regeneration feed stream 318 from the second inlet 334. A second plurality of conduits 106E, 106F, 106G, and 106H are configured for the regeneration feed stream 318 to flow downwards from the alkylation zone 120F and through the alkylation zones 120G, 120H, 120I, and 120J in the second mechanically separated catalytic volume 105B. Therefore, the regenerated feed stream 318 flows through the second plurality of alkylation zones 120F, 120G, 120H, 120I, and 120J and the second plurality of conduits 106F, 106G, 106H, and 106I to promote interaction with the spent alkylation catalyst therein under catalyst regeneration conditions, thereby regenerating the spent alkylation catalyst and producing a regenerated catalyst with significantly enhanced alkylation activity and a spent regenerated feed stream 336. In some embodiments, the catalyst regeneration conditions within the multi-zone alkylation reactor 102 include temperatures up to 275°C and pressures of approximately 290 psi (g). In some embodiments, reformer-grade hydrogen is used for catalyst regeneration. The spent regenerated feed stream 336 may exit at the outlet of the multi-zone alkylation reactor 102. A heat exchanger 324 may receive the spent regenerated feed stream 336 from the outlet of the multi-zone alkylation reactor 102 and produce a cooled spent regenerated feed stream 304. In some embodiments, cooler 326 may receive cooled waste recycled material stream 304 from heat exchanger 324 and further cool the cooled waste recycled material stream 304 to produce a second cooled waste recycled material stream 306. Gas-liquid separator 328 may receive cooled waste recycled material stream 304 from heat exchanger 324 and / or receive the second cooled waste recycled material stream 306 from cooler 326. In some embodiments, gas-liquid separator 328 may be a flash tank. In some embodiments, gas-liquid separator 328 may also receive liquid hydrocarbon stream 308. Gas-liquid separator 328 may separate waste materials, such as C1-C4 hydrocarbons, from cooled waste recycled material stream 304 and / or the second cooled waste recycled material stream 306 to produce substantially pure hydrogen stream 314 from which recycled material stream 312 may be extracted or separated. The gas-liquid separator 328 can also produce a waste material stream 340 containing materials to be removed (such as C1-C4 hydrocarbons). Therefore, the recycled stream 312 can be purified and regenerated for further use in the alkylation system 300.

[0041] Figure 4This is a schematic diagram of an alkylation system 400 including a multi-zone alkylation reactor 402. While some other embodiments have been described in the preceding figures as having downward flow in each of the mechanically separated catalytic volumes 105, the multi-zone alkylation reactor 402 provides downward fluid flow in a first mechanically separated catalytic volume 105A and upward fluid flow in a second mechanically separated catalytic volume 105B. Certain other components of the multi-zone alkylation reactor 402 may generally correspond to... Figure 1 The multi-zone alkylation reactor 102, wherein the corresponding elements can be described with reference to their operation within the alkylation system 400. For example, the multi-zone alkylation reactor 402 of this embodiment includes a plurality of alkylation zones 120, such as alkylation zones 120A, 120B, 120C, 120D, 120E, 120F, 120G, 120H, 120I, and 120J, which can be confined within a shell 103 and vertically spaced apart in a series configuration. At least one vertical partition 104 separates the plurality of alkylation zones 120 into at least a first mechanically separated catalytic volume 105A and a second mechanically separated catalytic volume 105B. Multiple olefin feed inlets 114, such as olefin feed inlets 114A, 114B, 114C, 114D, 114E, 114F, 114G, 114H, 114I, and 114J, can be positioned to supply an olefin-containing feed stream 110 to each of a plurality of alkylation zones 120 in two mechanically separated catalytic volumes 105A and 105B. An isobutane feed stream 112 is supplied to a first alkylation zone 120A in the first mechanically separated catalytic volume 105A. In this embodiment, the multi-zone alkylation reactor 102 includes a plurality of conduits 106 to guide the fluid flow of the alkylation feed stream through at least a portion of the plurality of alkylation zones 120. For example, the alkylation material flow within alkylation zone 120A can sequentially flow through conduit 106A, alkylation zone 120B, conduit 106B, alkylation zone 120C, conduit 106C, alkylation zone 120D, conduit 106D, and alkylation zone 120E. The first plurality of conduits 106A, 106B, 106C, and 106D can be configured to provide a downward fluid flow of alkylation material from alkylation zone 120A through alkylation zones 120B, 120C, 120D, and 120E in a first mechanically separated catalytic volume 105A.

[0042] The first alkylate product conduit 117 can transport the alkylate feed stream from the last alkylation zone 120E in the first mechanically separated catalytic volume 105A to the first alkylation zone 120F in the second mechanically separated catalytic volume 105B. In this embodiment, the first alkylation zone 120F is the lowest alkylation zone in the second mechanically separated catalytic volume 105B. Therefore, the second plurality of conduits 106F, 106G, 106H, and 106I can be configured to provide an upward fluid flow of the alkylate feed stream from the alkylation zone 120F through the alkylation zones 120G, 120H, 120I, and 120J in the second mechanically separated catalytic volume 105B. For example, the alkylate feed stream within the alkylation zone 120F can sequentially flow through conduit 106F, alkylation zone 120G, conduit 106G, alkylation zone 120H, conduit 106H, alkylation zone 120I, conduit 106I, and alkylation zone 120J. The second alkylate product conduit 118 can deliver the alkylate stream from the last alkylation zone 120J in the second mechanically separated catalytic volume 105B to the recirculation pump 108.

[0043] Therefore, the alkylation system 400 provides downward fluid flow in the first mechanically separated catalytic volume 105A and upward fluid flow in the second mechanically separated catalytic volume 105B. In some embodiments, this mixed or combined flow direction arrangement of the alkylation system 400 can achieve reduced or optimized lengths of conduits or conduits (e.g., including the first alkylate product conduit 117 and / or the second alkylate product conduit 118) compared to embodiments with downward or upward fluid flow in each mechanically separated catalytic volume 105.

[0044] When ranges are disclosed herein, a range beginning with any lower bound can be combined with any upper bound to enumerate ranges not explicitly listed, and a range beginning with any lower bound can be combined with any other lower bound to enumerate ranges not explicitly listed, and in the same way, a range beginning with any upper bound can be combined with any other upper bound to enumerate ranges not explicitly listed. Furthermore, references to values ​​stated within a range include every value within that range, even if not explicitly listed. Thus, each point or individual value can serve as its own lower or upper bound, or any other lower or upper bound, in combination with any other point or individual value, to enumerate ranges not explicitly listed.

[0045] Several embodiments of systems involving multi-zone alkylation reactors have been disclosed in the accompanying drawings and description. Although specific terminology has been used, it is for descriptive purposes only and not for limiting purposes. Embodiments of the systems and methods have been described in considerable detail with specific reference to the illustrated examples. However, it will be apparent that various modifications and changes can be made within the spirit and scope of the embodiments of the systems and methods described in the foregoing description, and such modifications and changes will be considered equivalents and part of this disclosure.

Claims

1. An alkylation system comprising: a multi-zone alkylation reactor comprising: a plurality of alkylation zones vertically spaced in a series configuration; at least one vertical partition dividing the plurality of alkylation zones into at least a first mechanically separate catalytic volume and a second mechanically separate catalytic volume; an isobutane inlet positioned to supply an isobutane stream to the first mechanically separate catalytic volume; at least one olefin feed inlet positioned to supply an olefin-containing stream to the plurality of alkylation zones, the olefin-containing stream reacting with the isobutane stream to produce an alkylate stream; and a first alkylate product conduit for transporting the alkylate stream from the first mechanically separate catalytic volume to the second mechanically separate catalytic volume.

2. The alkylation system of claim 1, wherein the multi-zone alkylation reactor comprises: a first plurality of conduits interconnecting each of the plurality of alkylation zones in the first mechanically separate catalytic volume; and a second plurality of conduits interconnecting each of the plurality of alkylation zones in the second mechanically separate catalytic volume.

3. The alkylation system of claim 1, wherein the plurality of alkylation zones are configured to direct the alkylate stream in a downward flow direction in each of the first mechanically separate catalytic volume and the second mechanically separate catalytic volume.

4. The alkylation system of claim 1, wherein the plurality of alkylation zones are configured to direct the alkylate stream in an upward flow direction in at least one of the first mechanically separate catalytic volume and the second mechanically separate catalytic volume.

5. The alkylation system of claim 1, wherein each of the first mechanically separate catalytic volume and the second mechanically separate catalytic volume is a hydraulically sealed reaction chamber.

6. The alkylation system of claim 1, wherein the at least one olefin feed inlet comprises a plurality of olefin feed inlets configured to supply the olefin-containing stream to each of the plurality of alkylation zones.

7. The alkylation system of claim 1, wherein the first alkylate product conduit is configured to transport the alkylate stream from a last alkylation zone in the first mechanically separate catalytic volume to a first alkylation zone in the second mechanically separate catalytic volume, and wherein the multi-zone alkylation reactor comprises a second alkylate product conduit for transporting the alkylate stream from a last alkylation zone in the second mechanically separate catalytic volume.

8. The alkylation system of claim 7, wherein the second alkylate product conduit is configured to transport the alkylate stream to a recycle pump.

9. The alkylation system of claim 8, comprising the recycle pump, wherein the recycle pump is configured to: receive the alkylate stream from the second alkylate product conduit; ​ directing a first portion of the alkylate stream for further processing to produce an enriched alkylate product containing high octane branched paraffins; and recycling a second portion of the alkylate stream to the first mechanically separated catalytic volume, thereby maintaining a ratio of isobutane to olefins in the multi-zone alkylate reactor in a range of about 300: 1 to about 500:

1.

10. The alkylate system of claim 8, comprising the recycle pump, wherein the recycle pump is configured to: receive the alkylate stream from the second alkylate product conduit; direct a first portion of the alkylate stream to a de-isobutanizer column; and recycle a second portion of the alkylate stream to the first mechanically separated catalytic volume, thereby maintaining a ratio of isobutane to olefins in the multi-zone alkylate reactor in a range of about 300: 1 to about 500:

1.

11. The alkylate system of claim 10, comprising the de-isobutanizer column, wherein the de-isobutanizer column is configured to separate the first portion of the alkylate stream from the recycle pump into: a recycle isobutane stream for supply to the first mechanically separated catalytic volume; a n-butane stream; and a product stream containing high octane branched paraffins.

12. The alkylate system of claim 1, wherein the multi-zone alkylate reactor comprises at least two vertical partitions defining three mechanically separated catalytic volumes.

13. The alkylate system of claim 12, wherein the multi-zone alkylate reactor comprises a second alkylate product conduit configured to transport the alkylate stream from the second mechanically separated catalytic volume to a third mechanically separated catalytic volume.

14. A method for producing alkylate, the method comprising: supplying an isobutane stream to a multi-zone alkylate reactor having at least one vertical partition defining: a first mechanically separated catalytic volume comprising a first plurality of alkylate zones; and a second mechanically separated catalytic volume comprising a second plurality of alkylate zones; supplying an olefin-containing stream through at least one olefin feed inlet to the first plurality of alkylate zones and the second plurality of alkylate zones to produce an alkylate stream; and directing the alkylate stream from the first plurality of alkylate zones through a first alkylate product conduit to the second plurality of alkylate zones.

15. The method of claim 14, further comprising: directing the alkylate stream from the second plurality of alkylate zones through a second alkylate product conduit to a recycle pump; and recycling a portion of the alkylate stream from the recycle pump to the first mechanically separated catalytic volume, thereby maintaining a ratio of isobutane to olefins in the multi-zone alkylate reactor in a range of about 300: 1 to about 500:

1.

16. The method of claim 14, further comprising: ​ ​ ​ directing the alkylate stream through the first plurality of alkylation zones in a downward flow direction; and directing the alkylate stream through the second plurality of alkylation zones in the downward flow direction.

17. The method of claim 14, further comprising: directing the alkylate stream through the first plurality of alkylation zones in a downward flow direction; and directing the alkylate stream through the second plurality of alkylation zones in an upward flow direction.

18. A method for regenerating alkylation zones of a multiple zone alkylation reactor, the method comprising: supplying a regeneration feed stream to an inlet of a multiple zone alkylation reactor, the multiple zone alkylation reactor having vertical partitions defining: a first mechanically separated catalytic volume comprising a first plurality of alkylation zones, and a second mechanically separated catalytic volume comprising a second plurality of alkylation zones; directing the regeneration feed stream through the first mechanically separated catalytic volume and through the second mechanically separated catalytic volume to regenerate spent alkylation catalyst therein by producing a regenerated catalyst having substantially increased alkylation activity and a spent regeneration stream; and directing the spent regeneration stream out of an outlet of the multiple zone alkylation reactor.

19. The method of claim 18, comprising producing the regeneration feed stream by: directing a regeneration stream containing at least 60 wt% hydrogen to a compressor to produce a compressed regeneration stream; supplying the compressed regeneration stream to a heat exchanger positioned to cross flow the compressed regeneration stream with the spent regeneration stream from the multiple zone alkylation reactor to produce a hot compressed regeneration stream and a cooled spent regeneration stream; and directing the hot compressed regeneration stream from the heat exchanger to a heater to produce the regeneration feed stream.

20. The method of claim 19, comprising: supplying the spent regeneration stream from the multiple zone alkylation reactor to the heat exchanger; and directing the cooled spent regeneration stream from the heat exchanger to a gas-liquid separator to separate spent material from the cooled spent regeneration stream to produce the regeneration stream and a spent material stream.

Images