Reactor system for dehydrogenation of saturated C3-C6 hydrocarbons

Abstract

A reactor system and method for catalytic dehydrogenation of saturated C3-C6 hydrocarbons in a reactor disposed within a reactor separator, the reactor being open at the bottom and open to the separator, and the outlet riser from the reactor not being hard-coupled to at least one downstream cyclone. With this configuration, the amount of catalyst in the reactor can be controlled by changing the catalyst level in the reactor separator outside the reactor, and the total catalyst hold-up and / or weight hourly space velocity (WHSV) can be controlled independently of the catalyst flow from the catalyst regeneration device.

Description

Detailed Description of the Invention

[0001] [Cross - Reference to Related Applications] This application claims priority based on U.S. Patent Application No. 17 / 829,818, filed on June 1, 2022, which is incorporated herein by reference.

[0002] [Technical Field] The present invention relates to a system and method for dehydrogenating saturated C3 - C6 hydrocarbons, and more particularly, to a system and method for dehydrogenating saturated C3 - C6 hydrocarbons that more appropriately control catalyst hold - up and gas residence time.

[0003] [Background] Techniques for performing dehydrogenation reactions of saturated hydrocarbons in an FCC (fluid catalytic cracking) type converter and the catalysts required therefor have been developed. In this description, the term "Cx" is used as a representative molecule of saturated hydrocarbons in the following description. For example, in one non - limiting embodiment, Cx refers to all molecules of C3 - C6, i.e., propane (C3), butane (C4), pentane (C5), and hexane (C6).

[0004] In a conventional FCC - style reactor design, the reaction is carried out in a dilute - phase fluidized riser, the residence time is typically 2 - 3 seconds, and the gas velocity is in the range of about 45 - 60 feet / second. In a typical riser design, the WHSV (weight hourly space velocity, i.e., the ratio of the feed mass flow rate in the reactor to the catalyst mass) is very high, usually exceeding 50 hr -1 -1. One non - limiting embodiment of this type of FCC - style reactor design is KBR's ORTHOFLOW® FCC.

[0005] The concept of WHSV is typically used for fixed-bed reactors loaded with a certain amount of catalyst. However, for FCC-style reactors, the effective or instantaneous WHSV can be defined based on the amount of catalyst in contact with the material at a specific point in time. To achieve the desired conversion rate (in a non-limiting embodiment, a 45% conversion rate) under favorable reactor temperature and pressure conditions, the gas contact time in the primary reaction zone should be maintained within the range of 2 to 3 seconds while keeping the WHSV much lower, usually in the range of 5 to 15 hr -1 . These conditions cannot be easily met in conventional riser-designed FCC-type reactors.

[0006] Fluidized bed reactors have the ability to process large amounts of fluid. Fluidization occurs when small solid catalyst particles are suspended in an upward-flowing fluid (gas) stream. The velocity of the fluid is sufficient to suspend the particles but not sufficient to carry the particles out of the vessel. The solid particles swirl rapidly around the bed and mix well with the fluid. The characteristics and operation of fluidized beds depend greatly on the characteristics of both the solid and the liquid or gas.

[0007] In commercial reactor technology, fixed-bed circulating reactor systems where multiple reactor beds alternate between reaction and regeneration operations, or moving-bed continuous catalyst regeneration systems with intermediate heating functions, are typically used. In these systems, semi-batch operations using multiple reactors and associated valves required to simulate continuous operation are performed.

[0008] Therefore, it is desirable to maintain true continuous operation while adopting a single reactor / regenerator system that can be easily realized by an FCC-type reactor / regenerator configuration. [Overview] As a non-limiting embodiment, a reactor system for the catalytic dehydrogenation of saturated Cx hydrocarbons is provided. The reactor system includes a reactor-separator, a reactor within the reactor-separator, the reactor having a reactor zone, a catalyst riser that is in fluid communication with the reactor at an upper end and in fluid communication with a spent catalyst stripper and a steam source at a lower end, and an outlet riser that is in fluid communication with the upper end of the reactor and is in fluid communication with at least one cyclone configured to separate catalyst from the reactor effluent. The reactor has a lower portion thereof that is open and not hard-coupled to at least one cyclone.

[0009] Further, a method for the catalytic dehydrogenation of saturated Cx hydrocarbons is provided. The method includes supplying a saturated Cx hydrocarbon and a dehydrogenation catalyst to a reactor within a reactor-separator, the reactor having a reactor zone including a lower portion thereof, dehydrogenating the saturated Cx hydrocarbon in the presence of the dehydrogenation catalyst, and supplying the reactor effluent to at least one cyclone through an outlet riser, separating the dehydrogenation product from the spent catalyst in at least one cyclone, and flowing the spent catalyst to a spent catalyst stripper located below the reactor through an annular space between the reactor and the reactor-separator. The lower portion of the reactor is open to the separator and is in fluid communication with the spent catalyst flowing down from the annular space from at least one cyclone. The method further includes controlling the level of catalyst in the reactor by varying the amount of catalyst in the annular space between the reactor and the reactor-separator.

Brief Description of the Drawings

[0010] It will be understood that the drawings are schematic and that the invention is not limited to the designs, ratios, or specific apparatus shown in the drawings.

Figure 1

Figure 2

Figure 3

Figure 4

[0011] [Detailed Description] The object of the present invention is, by way of non-limiting example, to operate at a WHSV in the range of 5 to 15 hr -1 and at the same time provide a reactor for Cx dehydrogenation that can enjoy most, if not all, of the advantages of conventional FCC-type conversion systems such as the KBR FCC ORTHOFLOW® design. FIG. 1 shows a schematic diagram of such a conventional reactor system. The present invention aims to: ? Achieve a low WHSV in the range of 5 to 15 hr with a gas contact time of 2 to 3 seconds in an FCC-style dilute-phase fluidized-bed reactor. -1 ? Provide a method for adjusting the WHSV in accordance with the reaction without affecting the heat balance of the entire reactor.

[0012] Another important parameter in reactor design is the gas residence time. In one non-limiting embodiment, the target range is 1 to 2 seconds within the reactor zone. The gas residence time is the reciprocal of the gas hourly space velocity (GHSV) and, in the case of the external riser reactor 116, is defined based on the volume of the riser (see FIG. 1). The gas residence time is also a function of the gas void fraction and is expressed as (reactor volume x gas void fraction) / volumetric flow rate.

[0013] Part of the concepts of the systems and methods described herein is to add a reactor portion with a relatively large diameter that achieves a much higher fluidized catalyst bed density than can be achieved by conventional risers by reducing the velocity of the gas moving upward through the reaction zone, i.e., by transitioning from a dilute phase state to a high-velocity fluidized state. This design enables the desired WHSV and gas residence time. In one non-limiting embodiment, it is desirable for the WHSV to be in the range of about 5 hr -1 to about 15 hr -1 or the WHSV is about 10 - 15 hr -1 . In another non-limiting form, the gas residence time is desirably in the range of about 0.5 seconds to about 3 seconds, or in the range of about 1 second to about 2 seconds, and in yet another non-limiting embodiment, it is in the range of less than 1 second within the reactor.

[0014] As defined herein, "reactor with a relatively large diameter" means that the reactor has a length and a diameter, and the ratio of length to diameter, L / D, is in the range from about 1:1 independently to about 5:1. Alternatively, it is in the range from about 2:1 independently to about 3:1. That is, the reactor is not in the typical shape of a riser or a pipe, but in the shape of a typical container. The term "independently" used herein with respect to ranges means that any endpoint can be combined with any other endpoint to provide a suitable alternative range.

[0015] These problems of FCC-type reactors are solved in the dehydrogenation reaction designs described herein, but these designs and methods are not limited to dehydrogenation reactions and are expected to be applicable to other reactions as well.

[0016] It is recognized that other reactor designs include the concept of providing a large-diameter reactor portion at the upper or lower part of the riser. However, what makes this design and method different from others are the following features.

[0017] · Laminated reactor regenerator configuration Referring to Figure 2, a non-limiting general schematic form of a reactor system 210 for the catalytic dehydrogenation of saturated C3-C6 hydrocarbons is shown.

[0018] a) The reactor section 212 is disposed within a reactor-separator 214 (a stacked reactor-regenerator configuration), as shown in Figure 2, as opposed to being on top of or below an external riser. b) The external riser 216 is not used for the reaction and is only used to transport the catalyst from the regenerator 218 to the reaction zone 220, thereby eliminating additional feed gas residence time in the riser. This is in contrast to using the external riser reactor 116 as a reactor in the conventional configuration shown in Figure 1. The steam introduced at 236 is used as a catalyst lift medium and also serves the additional purpose of lowering the hydrocarbon partial pressure to improve the selectivity of the reaction.

[0019] c) The catalyst and the reaction products are discharged from the reactor 212 through an outlet riser 222 operating in a typical riser dilution flow mode. The outlet riser 222 feeds material to a series of primary cyclones 224P and then sequentially to secondary cyclones 224S to separate the catalyst from the reactor effluent.

[0020] d) The quench gas is introduced via a quench gas supply (not shown) after the first set of cyclones 224P to lower (in one non-limiting embodiment) the gas temperature by about 25°C and suppress further cracking reactions. The quench gas is introduced before the second set of cyclones 224S.

[0021] e) The catalyst separated by the cyclones 224 flows down through an annular region 226 between the reactor 212 and the separator 214 to reach the spent catalyst stripper 228. f) Since the bottom 230 of the reactor section 212 is open, there is an advantage that the amount of catalyst in the reactor section 212 can be controlled by changing the level of the catalyst in the annular portion 226 of the separator 214 outside the reactor 212. With this design, the total catalyst hold-up / WHSV can be controlled independently of the regenerated catalyst flow from the regenerator 218, so that the WHSV in the reactor 212 can be changed without affecting the heat balance. The regenerated catalyst flows from the regenerator 218 to the regenerated catalyst stripper 238, and the stripped regenerated catalyst is introduced into the inlet 242 through the slide valve 240, and rises as steam 236 is introduced into the reactor 212 through the crossover 244. The regenerator 218 also includes an upper regenerator 219, a lower regenerator 221, and a regenerator cyclone 250. The exhaust gas from the regeneration cyclone 250 is discharged from the exhaust gas plenum 252.

[0022] g) In particular, since the outlet riser 222 is not hard-coupled to the cyclone 224 (gap 256), pressure equalization with the dilute space in the reactor separator 226 becomes possible, facilitating the level change described in f) above. More specifically, the cyclone 224 is hard-coupled to the upper part of the outlet riser 222 (negative pressure closed cyclone system). There is a gap 256 in the riser 222 before the first cyclone 224P, and the dipleg gas and steam are discharged from the reactor 212 through the cyclone system. The exact position of the gap 256 is not important. For example, it may be between the cyclones 224P and 224S. The level change in the annular region 226 is controlled independently by opening and closing the used catalyst slide valve 240 to change the level.

[0023] h) The Cx material 232 to the reactor 212 is introduced into the bottom 230 of the reactor 212 via the distributor 234. In one non-limiting embodiment, the distributor 234 has a mushroom-like shape or any other shape suitable for distributing the saturated hydrocarbon material to the reactor 212.

[0024] i) In another non-limiting embodiment, KBR's closed cyclone system is utilized to minimize gas residence time. j) In another non-limiting form, KBR's proven proprietary regenerator heating system (KCOT™) may be used.

[0025] · Alternative reactor regenerator configurations FIG. 3 shows a non-limiting alternative schematic form of a reactor system 310 for the catalytic dehydrogenation of saturated Cx hydrocarbons.

[0026] a) The reactor section 312 is arranged inside the reactor separator 314 in a different stacked reactor regenerator configuration, as shown in FIG. 3, as opposed to the upper or lower part of an external riser. b) Again, the external riser 316 is not used for the reaction and is only used to transport the catalyst from the regenerator 318 to the reaction zone 320, thereby eliminating additional feed gas residence time in the riser. This is in contrast to using the external riser reactor 116 as a reactor in the conventional configuration shown in FIG. 1. The steam introduced at 336 is used as a catalyst lift medium and also serves the additional purpose of lowering the hydrocarbon partial pressure to improve the selectivity of the reaction.

[0027] c) The catalyst and reaction products are discharged from the reactor 312 through an outlet riser 322 operating in a general riser dilution flow mode. The outlet riser 322 continuously feeds material to a cyclone 324 (primary cyclone 324P and secondary cyclone 324S) to separate the catalyst from the reactor effluent.

[0028] d) The quench gas is introduced after the first set of cyclones 324P via a quench gas supply (not shown) and (in one non-limiting embodiment) lowers the gas temperature by about 25 °C to suppress further cracking reactions. The quench gas is introduced before the second set of secondary cyclones 324S.

[0029] e) The catalysts separated by cyclones 324P and 324S flow down through the annular region 326 between the reactor 312 and the separator 314 and reach the spent catalyst stripper 328.

[0030] f) Since the bottom 330 of the reactor section 312 is open, there is an advantage that the amount of catalyst in the reactor section 312 can be controlled by changing the level of the catalyst in the annular portion 326 of the separator 314 outside the reactor 312. With this design, the total catalyst hold-up / WHSV can be controlled independently of the catalyst flow from the regenerator 318, so that the WHSV in the reactor 312 can be changed without affecting the heat balance. The regenerated catalyst flows from the regenerator 318 to the regenerated catalyst stripper 338, and the stripped regenerated catalyst is introduced into the riser 316 through the slide valve 340, and rises as steam 336 is introduced into the reactor 312 through the crossover 344. The regenerator 318 also includes an upper regenerator 319, a lower regenerator 321, and a regenerator cyclone 350. The exhaust gas from the regeneration cyclone 350 is discharged from the exhaust gas plenum 352.

[0031] g) In particular, since the outlet riser 322 is not hard-coupled to the cyclone 324 (there is a gap 356), pressure equalization with the dilute space in the reactor separator 326 becomes possible, facilitating the level change described in f) above. The details described above regarding the stacked reactor regenerator configuration of g) in FIG. 2 are equally applicable to this alternative configuration.

[0032] h) The Cx material 332 (e.g., propane material) to the reactor 312 is introduced into the bottom 330 of the reactor 312 through a ring-type distributor in a non-limiting embodiment. Other suitable types of distributors include, but are not limited to, grid-type, mushroom-type, or any suitable design that achieves thorough distribution.

[0033] i) Instead of being directly introduced from crossover 344 into reactor 312, the regenerated catalyst and the rising vapor enter the bottom 330 of reactor 312 via crossover 344 through opening 348. In one non-limiting embodiment, the open opening 348 distributes the regenerated catalyst and the rising vapor to reactor 312. The shape and number of openings 348 are not critical as long as the regenerated catalyst and the rising vapor are well distributed to reaction zone 320.

[0034] Other details of the alternative system 310 of FIG. 3 are the same as the details of the system 210 of FIG. 2. · Parallel reactor regenerator configuration A second configuration, more precisely a parallel reactor regenerator configuration, is also envisioned and is shown in FIG. 4. This configuration is very similar to the configuration shown in FIG. 3 except that the separator 414 that makes up reactor 412 has been moved laterally from the position shown in FIG. 3 to that shown in FIG. 4. In the non-limiting embodiment of FIG. 4, it is disposed above the riser 416 (to the left and optionally below with respect to the embodiment of FIG. 3). In any embodiment, the separator 414 and the reactor 412 may be coaxial with the riser 416. Thus, the reactor 412 and the regenerator 418 are in a parallel relationship rather than a stacked relationship. More specifically, a) The riser 416 (external or internal) is used to transport the catalyst from the regenerator 418 to the reactor 412.

[0035] b) For the external riser 416, refer to the descriptions of items a) to j) of the "stacked reactor regenerator configuration" described above. c) In the case of the internal riser 416, a part of the riser 416 can also be used for the reaction. When used to cause a reaction, the Cx feed is introduced into the riser 416 so that the portion or length of the riser reaction zone is minimized.

[0036] d) The vapor 436 is used as the main catalyst rising medium in the riser 416 and also serves the additional purpose of reducing the hydrocarbon partial pressure and improving the reaction selectivity. e) The catalyst and the reaction product are discharged from the reactor 412 through an outlet riser 422 operating in a common riser dilution flow mode. The outlet riser 422 continuously feeds materials to cyclones 424P and 424S to separate the catalyst from the reactor effluent.

[0037] f) The quench gas is introduced after the primary cyclone 424P via a quench gas supply (not shown) to lower the gas temperature by about 25°C and suppress further cracking reactions. The quench gas is introduced before the secondary cyclone 424S.

[0038] g) The catalyst separated by the cyclone 424 flows down through an annular region 426 between the reactor 412 and the separator 414 to reach the spent catalyst stripper 428. h) As described above, since the bottom 430 of the reactor section 412 is open, there is an advantage that the amount of catalyst in the reactor 412 can be controlled by changing the level of the catalyst in the annular portion 426 of the separator 414 outside the reactor 412. With this design, the overall catalyst hold-up / WHSV can be controlled independently of the catalyst flow from the regenerator 418, so that the WHSV in the reactor 412 can be changed without affecting the heat balance.

[0039] i) Again, the outlet riser 422 is not hard-coupled to the cyclone 424 (there is a gap 456). This enables pressure equalization with the dilute space in the reactor separator 426 and facilitates the level change described in f) above. Also, the above details regarding the stacked reactor regenerator configuration of g) in Figure 2 and the alternative reactor regenerator configuration of g) in Figure 3 are equally applicable to this parallel configuration.

[0040] j) Additional Cx material 432 to the reactor 412 can also be introduced to the bottom of the reactor 412 via a distributor as described above. Other details of the parallel system are the same as those of the stacked reactor regenerator system and the alternative reactor regenerator system described above. For example, the slide valve 454 in FIG. 4 corresponds to the plug valve 354 in FIG. 3. In some embodiments, it is expected that the installation area will be relatively small in a stacked configuration. On the other hand, when vertical space is precious, a parallel system is suitable.

[0041] In the design of this system (FIGS. 2, 3, 4), the catalyst in the reactor (212, 312, 412) is a combination of the regenerated catalyst entering from the riser (216, 316, 416) and the spent catalyst entering the bottom of the reactor (212, 312, 412) from the separator (214, 314, 414). The reactor effluent and the catalyst are discharged from the reactor (212, 312, 412) through the outlet riser (222, 322, 422) operating in a typical riser flow mode.

[0042] The main components entering the internal reactor are four: newly regenerated catalyst, spent catalyst, steam, and Cx material. In this section, some additional functions and potential arrangements for introducing these components will be described.

[0043] · Regenerated catalyst The regenerated catalyst, together with the rising steam (236, 336), is transferred from the vertical external riser (216, 316) to the side of the internal reactor (212, 312) via the crossover duct (244, 344) in a non-limiting embodiment. The catalyst is introduced above the Cx supply distributor (234) (see FIG. 2). This can be achieved using one or more risers.

[0044] The regenerated catalyst, together with the rising steam (236, 336), is transferred from the vertical external riser (216, 316) through the horizontal crossover duct (244, 344) and an additional internal vertical riser to the central part at the bottom of the internal reactor. The catalyst is introduced at approximately the same level as the Cx supply distributor (234). The catalyst is distributed over the entire cross-sectional area of the reactor (212, 312) via a catalyst distributor (the opening 348 of a vertical riser or other suitable catalyst distribution device; see FIG. 3).

[0045] In a parallel reactor regenerator configuration with an internal riser, the regenerated catalyst and the rising steam (436) and optionally Cx are transferred from the vertical internal riser, in one non-limiting embodiment, to the center of the internal reactor (412). In other non-limiting embodiments, the catalyst is introduced above or at the same level (if present) as the additional Cx feed distributor 432 (see FIG. 4). This can be achieved using one or more risers 416.

[0046] · Cx material Cx can be introduced via a distributor 234 at the bottom of the internal reactor 212 (see FIG. 2).

[0047] The Cx distributor 234 is a mushroom / dome type, grid type, ring type, riser nozzle, or other type of distributor suitable for introducing Cx into the internal reactor or riser.

[0048] The Cx distributor 234 is designed to cover the entire cross-sectional area of the reactor (212, 312, 412) well and bring the catalyst and the Cx material into close contact. To promote mixing before entering the reactor (212, 312), Cx can also be introduced into a horizontal crossover (244, 344) or a riser. This can be implemented in either a bottom-entry or side-entry configuration.

[0049] In the reactor designs described herein, combining Cx with steam (236, 336, 436) enables a high-speed fluidized catalyst bed reactor system in which the required WHSV is achieved.

[0050] · Spent catalyst The spent catalyst is introduced via a cyclone dip leg after the catalyst is separated from the product gas in the cyclone (224, 324, 424) and enters the annular space (226, 326, 426) between the internal reactor (212, 312, 412) and the walls of the separator (214, 314, 414).

[0051] The spent catalyst enters the internal reactors (212, 312, 412) through the open bottoms (230, 330) and is mixed with the Cx material (232, 332, 432) and the newly regenerated catalyst. There is a potential yield advantage in the order of first mixing the Cx material with the low-temperature spent catalyst and then with the fresh catalyst. Also, the catalyst beds below and around the reactors (212, 312, 412) are in a relatively high-density phase.

[0052] The high-density catalyst beds are maintained below the reactors (212, 312) and within the annular spaces (226, 326) between the internal reactors (212, 312) and the walls of the separators (214, 314).

[0053] The un-recycled spent catalyst flows into the stripper vessels (238, 338, 438) below the internal reactors (212, 312, 412) and then into the regenerators (218, 318, 418), where it is regenerated and returned to the internal reactors (212, 312, 412).

[0054] · Catalyst Bed Adjustment The catalyst hold-up (or WHSV) within the reaction vessels (212, 312, 412) can be varied by changing the amount of recycled spent catalyst that returns from the cyclone dip legs and enters the reaction vessels (212, 312, 412) from the open bottoms of the reaction vessels (212, 312, 412).

[0055] This design includes the flexibility to vary the height of the catalyst within the annular spaces (226, 326, 426) outside the reactors (212, 312, 412). This allows control of the amount of spent catalyst recycled to the reactors (212, 312, 412). This concept is based on the catalyst bed hydraulic pressure. As the annular bed level increases, the pressure head increases and more spent catalyst is pushed into the reactors (212, 312, 412). Conversely, as the annular bed level decreases, the pressure head decreases and the amount of spent catalyst entering the reactors (212, 312, 412) decreases.

[0056] The bed density of the reactor is typically lower than the bed density of the annular spaces (212, 312, 412) around the reactor and the bed density below the reactor (212, 312, 412), but by controlling the height of the annular bed via the spent catalyst plug valve / slide valve (254, 354, 454), the recirculation of the spent catalyst can be adjusted regardless of the bed density of the annular portion (226, 326, 426). The difference in the density of the catalyst bed affects the final height of the catalyst bed within the annular space (226, 326, 426), but as long as there is flexibility to change the height of the bed in the annular space (226, 326, 426), the actual density of the annular bed is not a problem. In one non-limiting embodiment, the density of the annular bed is ideally about 30 - 40 lb / ft 3 although the concepts, designs, and methods described herein can operate outside of this range.

[0057] This annular bed catalyst level is controlled by the adjustment of the spent catalyst plug valve (254, 354) in the stacked design of FIGS. 2 and 3, or the slide valve (454) in a parallel design such as FIG. 4. Close the valves (254, 354, 454) to increase the catalyst inventory / height of the annular bed. Open the valves (254, 354, 454) to decrease the catalyst inventory / height of the annular bed. This is similar to the general method of maintaining the reactor / stripper bed level in FCC, but now operates over a wider range of levels.

[0058] The cyclone system is hard-coupled to the upper part of the outlet risers (222, 322, 422). The bottom of the outlet risers (222, 322, 422) is attached to the reactors (212, 312, 412). There are gaps (256, 356, 456) in the outlet risers (222, 322, 422) before the first-stage cyclones (224P, 324P, 424P), whereby dipleg gas and vapor are discharged from the lean phase of the separators (214, 314, 414) through their respective cyclone systems, and the pressure between the lean phase of the separators (214, 314, 414) and the cyclone system is equalized. The inlet pressure of the first-stage cyclones (224P, 324P, 424P) is equal to the lean phase pressure of the separators (214, 314, 414). As described above, this pressure equalization gap (256, 356, 456) can be arranged before the primary cyclones (224P, 324P, 424P), between the primary cyclones (224P, 324P, 424P) and the secondary cyclones (224S, 324S, 424S), or after the secondary cyclones (224S, 324S, 424S). The arrangement before the primary cyclones (224P, 324P, 424P) shown in FIGS. 2, 3, and 4 is suitable in one non-limiting embodiment.

[0059] The catalyst bed level within the annular portions (226, 326, 426) does not affect the cyclone pressure balance. In any case, due to the pressure equalization function, the entire system operates normally. Without the pressure equalization function, there would be no place for the vapor and dipleg gas to escape, so the lean phase pressure of the separator would continue to increase. The cyclone system would not operate properly. Furthermore, it becomes increasingly difficult to control the annular bed level and the recirculation of the spent catalyst.

[0060] The amount of catalyst in a typical FCC riser varies by increasing the catalyst circulation (by various means such as increasing the reactor temperature and decreasing the feed temperature). These adjustments also change the heat balance.

[0061] In contrast, in the present system, by changing the recycle amount of the spent catalyst, the amount of catalyst in the reactor can be changed without affecting the heat balance, and the amount of the circulating catalyst does not change. The WHSV adjustment is independent of the catalyst circulation / regenerated catalyst flow.

[0062] · Steam Steam (236, 336, 436) is used to lift the regenerated catalyst along the external riser or internal riser (216, 316, 416) and feed it into the reactor (212, 312, 412).

[0063] It will be understood that other gases (e.g., N2) and / or steam can also be used as the catalyst lifting medium. One of the non-limiting advantages of the systems and methods described herein is that the low WHSV required for the Cx dehydrogenation reaction can be accommodated in an FCC-type reactor. In a conventional fixed-bed reaction system, there are problems with periodic operation and associated maintenance, but by using an FCC-type reactor, periodic operation is avoided and catalyst replenishment is carried out continuously.

[0064] In the foregoing specification, the invention has been described with reference to its specific embodiments. However, this specification is not to be taken in a limiting sense, but rather should be considered in an illustrative sense. For example, devices, risers, reactors, separators, columns, regenerators, valves, gaps, processes, reactants, saturated hydrocarbons, products, and operating conditions that are within the scope of the claims or disclosed parameters but have not been specifically identified or tried in a particular instance are considered to be within the scope of the invention.

[0065] The present invention can be practiced even in the absence of elements that are not disclosed. Further, the present invention may suitably include, consist of, or consist essentially of the disclosed elements. For example, a reactor system for the catalytic dehydrogenation of saturated Cx hydrocarbons may be provided, the reactor system consisting essentially of or consisting of a reactor separator, a reactor within the reactor separator having a reactor zone, a catalyst riser in fluid communication with the reactor at its upper end and in fluid communication with a spent catalyst stripper and a steam source at its lower end, and an outlet riser in fluid communication with the upper end of the reactor and in fluid communication with at least one cyclone configured to separate catalyst from the reactor effluent. The reactor has a lower portion open to the reactor separator.

[0066] Further, a method for the catalytic dehydrogenation of saturated Cx hydrocarbons may be provided. The method consists essentially of or consists of feeding a saturated Cx hydrocarbon and a dehydrogenation catalyst to a reactor within a reactor separator having a reactor zone including its lower portion, dehydrogenating the saturated Cx hydrocarbon in the presence of the dehydrogenation catalyst and feeding the reactor effluent to at least one cyclone through an outlet riser, separating the dehydrogenation product from the spent catalyst in the at least one cyclone, flowing the spent catalyst through an annular space between the separator and the reactor to a spent catalyst stripper and then to a catalyst regenerator. The lower portion of the reactor is open to the separator and in fluid communication with the annular space. The method further includes controlling the amount of catalyst in the reactor by varying the level of catalyst in the annular space.

[0067] Throughout the claims, the terms "comprising" and "comprises" are to be interpreted as meaning "including but not limited to" respectively.

[0068] As used herein, the term "substantially" means "most but not all of what is specified". As used herein, the terms "a," "an," and "the" include the plural thereof unless the context clearly dictates otherwise.

[0069] As used herein, the term "about" when used with respect to a particular parameter includes the recited value and has the meaning determined by the context (e.g., it includes the degree of error associated with the measurement of the particular parameter).

[0070] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

Claims

1. A reactor system for catalytic dehydrogenation of saturated Cx hydrocarbons, wherein the reactor system is Reactor separator, A reactor within the reactor separator, comprising a reactor zone, A catalyst riser that has fluid communication with the reactor at its upper end and fluid communication with the regenerating catalyst stripper and steam source at its lower end, An outlet riser that is in fluid communication with the upper end of the reactor, The system comprises at least one cyclone configured to communicate with the outlet riser and separate the catalyst from the reactor effluent, The lower part of the reactor includes an opening to the reactor separator. Reactor system.

2. The reactor system according to claim 1, wherein the reactor has a length and a diameter, and the ratio of the length to the diameter is in the range of about 1:1 to about 5:

1.

3. The reactor system according to claim 1, wherein the outlet riser is open to at least one cyclone.

4. The reactor system according to claim 1, wherein the reactor separator has a lower part that is in fluid communication with a catalyst regenerator.

5. The at least one cyclone comprises at least one primary cyclone and at least one secondary cyclone, The reactor system according to claim 1, further comprising a quench gas supply unit located downstream of at least one primary cyclone and upstream of the secondary cyclone.

6. The reactor system according to claim 1, further comprising a saturated Cx hydrocarbon supply unit that is in fluid communication with the lower part of the reactor.

7. The reactor system according to claim 6, wherein the reactor has an open bottom, and the saturated Cx hydrocarbon supply unit, which is in fluid communication with the lower part of the reactor, supplies material to a distributor located at the bottom of the reactor.

8. The reactor system according to claim 4, wherein the reactor and the reactor separator are positioned above the catalyst regenerator, and the catalyst riser is located outside the reactor separator and the catalyst regenerator.

9. The reactor system according to claim 4, wherein the reactor and the reactor separator are arranged on the side of the catalyst regenerator, and the catalyst riser is located outside or inside the reactor separator and the catalyst regenerator.

10. The reactor system according to claim 9, wherein, when the catalyst riser is located inside the reactor separator, at least a portion of the catalyst riser is a reactor.

11. A reactor system for the catalytic dehydrogenation of saturated C3-C6 hydrocarbons, wherein the reactor system is Reactor separator, A reactor within a reactor separator, comprising a reactor zone, A catalyst riser that has fluid communication with the reactor at its upper end and fluid communication with the regenerating catalyst stripper and steam source at its lower end, An outlet riser that is in fluid communication with the upper end of the reactor, The system comprises at least one cyclone configured to communicate with the outlet riser and separate the catalyst from the reactor effluent, The lower part of the reactor includes an opening to the reactor separator and is not hard-coupled to the at least one cyclone. The reactor system comprises a reactor having a length and a diameter, wherein the ratio of the length to the diameter is in the range of about 1:1 to about 5:

1.

12. A method for catalytic dehydrogenation of saturated Cx hydrocarbons, A reactor within a reactor separator, comprising a reactor zone including its lower part, to which saturated Cx hydrocarbons and a dehydrogenation catalyst are supplied; Dehydrogenating the saturated Cx hydrocarbon in the presence of the dehydrogenation catalyst, and supplying the reactor effluent to at least one cyclone through the outlet riser, The separation of dehydrogenation products from the spent catalyst using at least one cyclone, This includes flowing the spent catalyst through the annular space between the reactor separator and the reactor to the spent catalyst stripper and the catalyst regenerator, The lower part of the reactor is open to the reactor separator and is in fluid communication with the annular space, and the method further includes controlling the amount of catalyst in the reactor by changing the level of catalyst in the annular space. Catalytic dehydrogenation method.

13. The catalytic dehydrogenation method according to claim 12, wherein the reactor has a length and a diameter, and the ratio of the length to the diameter is in the range of about 1:1 to about 5:

1.

14. The catalytic dehydrogenation method according to claim 12, wherein the total catalyst hold-up and / or gravitational space velocity (WHSV) is controlled independently of the catalyst flow from the catalyst regenerator.

15. The catalytic dehydrogenation method according to claim 12, wherein the outlet riser is open and the pressure between the reactor and the reactor separator is equalized.

16. The at least one cyclone comprises at least one primary cyclone and at least one secondary cyclone, The catalytic dehydrogenation method according to claim 12, wherein a quench gas is introduced downstream of the at least one primary cyclone and upstream of the at least one secondary cyclone.

17. The catalytic dehydrogenation method according to claim 12, wherein the reactor has an open bottom, and the saturated Cx hydrocarbon is supplied to the reactor via a distributor at the bottom of the reactor.

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