Apparatus for mixing in a catalytic cracking reactor

Abstract

The present invention provides a catalytic cracking reactor comprising a conduit configured to allow passage of a catalyst particle stream and an injection zone including a ring of feed injectors extending inwardly from the reactor wall and angled to inject a feed into the catalyst particle stream, characterized in that the reactor also includes a contactor protruding into the reactor from the inner wall of the reactor upstream of the injection zone. The present invention also provides a method of mixing a fluidized catalyst particle stream with a hydrocarbon feed, the method comprising the steps of: a) generating a fluidized catalyst particle stream in the reactor; b) passing the fluidized catalyst particle stream through a contactor protruding into the reactor from the inner wall of the reactor; c) subsequently passing the fluidized catalyst particle stream through an injection zone including a ring of feed injectors extending inwardly from the reactor wall to contact the fluidized catalyst particle stream with a hydrocarbon feed provided through the feed injector; and d) passing the fluidized catalyst particle stream contacted with the hydrocarbon feed to a downstream section of the reactor to convert the hydrocarbon feed into conversion products in the presence of the catalyst particles.

Description

Technical Field

[0001] The present invention relates to an apparatus and a process for improving the dispersion of a liquid into a flowing solid within a reactor. More particularly, the present invention relates to an apparatus and a process for dispersing hydrocarbons into a flowing stream of catalyst particles.

Background Art

[0002] In processes using fluid solid catalyst bed technology, carbonaceous materials are often deposited on the catalyst particles within the bed. Often, these processes are carried out on a recycle basis, where the spent catalyst solids are removed from the reactor and transported to another vessel where the carbonaceous material is removed by combustion in an oxygen-containing environment. This allows for the reuse of the catalyst once it is returned to the reactor.

[0003] An important process of this nature is the fluid catalytic cracking (FCC) process for converting relatively high boiling hydrocarbons into lighter hydrocarbons that boil in the heating oil or gasoline (or lighter) range. In this process, a hydrocarbon feedstock is contacted with a granular cracking catalyst in a fluid catalyst bed under conditions suitable for the conversion of the hydrocarbons.

[0004] Modern FCC units typically use a pipe-type reactor in the form of a large, usually vertical riser, in which a gaseous medium transports the catalyst upward in a fluid state. However, in some cases, vertical reactors are also used, with a downward flow.

[0005] For an efficient process, it is desirable that the hydrocarbon feed material be instantaneously dispersed throughout the entire flow of catalyst moving through the reactor. While complete and instantaneous dispersion of the feed material across the entire cross-section of the reactor is impossible, good results have been obtained by injecting highly atomized feed material into the pre-enhancing flow of catalyst particles. However, the dispersion of the feed material throughout the catalyst particles takes some time, resulting in some non-uniform contact between the feed material and the catalyst, as mentioned above. Non-uniform contact between the feed material and the catalyst exposes some of the feed material to the catalyst for a longer period of time, which can then lead to thermal decomposition and degrade the quality of the reaction product.

[0006] Many different methods are used to maximize the dispersion of hydrocarbon feed material in a granular catalyst suspension. Dispersion of the feed material is improved by separating it into droplets, thereby increasing the interaction between the liquid and solid. Preferably, the droplet diameter is small enough to allow the liquid to vaporize before it comes into contact with the solid. It is also well known, as in U.S. Patent No. 4479870, that catalyst particles are pre-fostered before contacting the hydrocarbon feed material.

[0007] The hydrocarbon feed material is typically placed in a circumferential band around the reactor and injected into the reactor through multiple angled feed nozzles that inject the feed material toward the center of the riser tube. These nozzles typically protrude into the reactor.

[0008] U.S. Patents 5,554,341, 5,173,175, 4,832,825, and 3,654,140 all describe the use of radially oriented feed material injection nozzles for introducing feed material into FCC risers. The nozzle arrangement maintains a substantially open riser cross-section across the feed material injection zone and the downstream riser section. Angled feed nozzles are typical for use in injecting feed material or other fluids in the middle portion of the riser conduit.

[0009] However, angled feed nozzles typically extend away from the reactor wall into the catalyst flow path. Passing particles over the nozzle at high speed can lead to erosion. Furthermore, the nozzle's protrusion into the reactor can create a static zone where the catalyst is flowing, but a limited amount of hydrocarbon feed material is supplied within the feed material injection zone.

[0010] It is undesirable to completely embed the nozzles within the reactor wall and remove them from the catalyst flow path. This solution is unsatisfactory because the tips of the feed material injectors are specifically designed to provide a relatively uniform application of hydrocarbon feed material across the reactor cross-section by expanding the feed material injection pattern as the feed material exits the nozzle. Completely embedding the tips of the injection nozzles within the reactor wall hinders the ability to obtain a spray pattern over a large portion of the riser tube cross-sectional area.

[0011] U.S. Patent No. 7101474 describes an improved FCC riser tube that increases the thickness of the riser tube wall below the feed material injection area to provide a narrower catalyst particle flow through the nozzle. This requires a new riser tube structure.

[0012] The object of the present invention is to provide a simple apparatus and method for more uniformly distributing catalyst and oil across the cross-section of a reactor. [Brief explanation of the drawing]

[0013] [Figure 1] This shows an example of the prior art injection zone in an FCC riser tube. [Figure 2a] The contact device according to the present invention is shown. [Figure 2b] The contact device according to the present invention is shown. [Figure 3] A suitable contact device is shown. [Figure 4] A suitable contact device is shown. [Figure 5] A portion of the catalytic cracking riser reactor of the present invention is shown. [Overview of the Initiative]

[0014] The present invention provides a catalytic cracking reactor comprising a conduit configured to allow the passage of a catalyst particle flow, and an injection zone including a ring of a feed material injector extending inward from the wall of the reactor and angled to inject feed material into the catalyst particle flow, wherein the reactor also comprises a contact device protruding into the reactor from the inner wall of the reactor upstream of the injection zone.

[0015] The present invention also provides a method for mixing a flow of fluid catalyst particles with a hydrocarbon supply material, the method being a) A step of generating a flow of fluid catalyst particles in a reactor, b) A step of passing the fluid catalyst particle stream through a contact device protruding from the inner wall of the reactor into the reactor, c) Next, the fluid catalyst particle flow is passed through an injection zone including a ring of a feed material injector extending inward from the wall of the reactor, bringing the hydrocarbon feed material provided through the feed material injector into contact with the fluid catalyst particle flow. d) A step of passing a flow of fluid catalyst particles, which has been in contact with a hydrocarbon supply material, through the downstream section of the reactor to convert the hydrocarbon supply material into a conversion product in the presence of catalyst particles. [Modes for carrying out the invention]

[0016] The inventors have found that mixing of hydrocarbon feed material and fluid catalyst particle flow is improved by providing a contact device in the reactor upstream of the feed material injector ring that supplies hydrocarbon feed material to the reactor. The present invention provides a simple solution to the problem of providing rapid and uniform dispersion of hydrocarbon feed material into fluid catalyst particle flow.

[0017] The reactor is preferably a reactor for use in a fluid catalytic cracking (FCC) process. In such a process, ultrafine catalyst particles are supplied to the reactor and fluidized by the addition of a fluidizing medium. The catalyst particles may be fresh catalyst particles, regenerated catalyst particles, or a mixture thereof. The fluidizing medium may be a diluent material for a hydrocarbon stream, typically steam or a low molecular weight fluidizing gas. The fluid catalyst stream flows through the reactor. The reactor may be a "downer" reactor in which the fluid catalyst stream flows downward through the reactor. Preferably, the reactor is a riser reactor and the fluid catalyst stream flows upward through the riser reactor.

[0018] In the present invention, the contacting device is provided in the reactor upstream of the ring of the feed injector. Thus, the fluid catalyst stream is brought into contact with the contacting device before passing into the injection zone.

[0019] The contacting device includes an insertion part firmly fixed to the wall of the reactor. Typically, the contacting device comprises an annular element having an outer diameter equal to the inner diameter of the reactor.

[0020] The contacting device may include metal, ceramic, cermet, or a mixture thereof. In one embodiment of the present invention, the contacting device includes a composite material of a refractory material and a metal structure. In this embodiment, the metal structure may be connected to the outer wall of the reactor to ensure that the position of the contacting device does not change during operation despite temperature shocks.

[0021] Furthermore, the metal structure provides reinforcement to the combination of the metal structure and the refractory material, thereby making it stronger and less prone to erosion. This is particularly advantageous when the reactor has an internal refractory lining.

[0022] Taking into account the corrosivity of the reactor mixture, the refractory material is appropriately selected to have high wear resistance. The material is also preferably castable to facilitate the shaping of the contacting device. Preferably, the refractory material is selected from the group consisting of alumina, silica, calcium oxide, titanium oxide, magnesium oxide, iron oxide, and mixtures thereof. The refractory may also contain phosphorus oxide.

[0023] The contacting device may have any cross-sectional shape that one skilled in the art would consider suitable for a particular application. One skilled in the art will optimize the advantages, particularly the turbulent flow effect, and minimize any drawbacks such as pressure drop. In certain embodiments, the contacting device may have a rectangular cross-sectional profile. In other embodiments, a non-rectangular cross-section may be desirable. For example, a tapered shape that slopes outward from the inner wall of the reactor may be suitable. Suitable devices are described in U.S. Patent No. 9,283,532, International Publication No. 02017 / 003991, and International Publication No. 02008 / 017660.

[0024] When the contacting device is in the shape of a ring, the entire ring may be assembled integrally. However, it is advantageous to assemble such a ring into two or more modules. This not only makes assembly easier but also provides the possibility of local repair. In this embodiment, the number of modules is preferably in the range of 4 to 25.

[0025] A particular advantage of the present invention is that the contacting device configured in this way can be additionally introduced into the reactor, enabling the improvement of an existing reactor without requiring major modifications. The contacting device is positioned upstream of the ring of the feed injector. Typically, the contacting device is disposed immediately upstream of the ring of the feed injector. Preferably, the distance between the downstream end of the contacting device and the upstream end of the feed injector is 25 inches (63.5 cm) or less. The distance between the downstream end of the contacting device and the upstream end or underside of the feed injector depends on the shape of the reactor and whether the reactor is swaged, and can be varied depending on both the shape and flow conditions within the reactor.

[0026] The position of the contact device upstream of the feed material injector ring deflects the catalyst particle flow, making it more closely matched to the dispersion of hydrocarbon feed material from the feed material injector. The contact device reduces the passage in the reactor. Preferably, the passage is reduced by 35 percent or less compared to the reactor passage upstream of the contact device. Preferably, the passage reduction is at least 10 percent compared to the reactor passage upstream of the contact device.

[0027] The position of the contact device upstream of the feed material injector ring offers the further advantage of protecting the feed injector itself from erosion and damage caused by the catalyst particle flow.

[0028] The feed material injector may include any suitable feed material injection nozzle. In a typical FCC implementation, the feed material exits the nozzle as a fan-shaped spray pattern. The nozzle is typically angled to tilt the fan-shaped pattern downstream. The nozzle angle is typically in the range of at least 20° to less than 70° with respect to the cross-section through which the liquid enters the injector.

[0029] Within the injection zone, the fluid catalyst particles come into contact with the hydrocarbon feed material supplied through the feed material injector. The present invention enables excellent and rapid dispersion of the feed material throughout the catalyst particles.

[0030] Next, a flow of fluid catalyst particles in contact with the hydrocarbon feed material is passed downstream of the injection zone, converting the hydrocarbon feed material into a conversion product in the presence of the catalyst particles. This can occur as part of the flow through the reactor, or, in some embodiments, at least partially, within a catalyst bed located in the downstream section of the reactor.

[0031] Detailed description of the drawing The present invention will now be further described with reference to representative and non-limiting drawings.

[0032] Figure 1 illustrates the problem to be overcome by the present invention. Figure 1 shows a cross-section of a riser reactor in the injection zone. Multiple feed material injectors (1) protrude from the inner wall of the riser reactor (2). A combined spray pattern (3) in a typical reactor configuration is shown. This results in a stationary zone (4) where the fluid catalyst particle flow passing through the injection zone comes into contact with a reduced level of feed material.

[0033] Figures 2a and 2b illustrate the present invention. The contact device (5) is provided upstream of the injection zone. In Figure 2a, the area of ​​the passage for the fluid catalyst particles is reduced by 23% by the contact device based on the passage of the riser reactor upstream of the contact device. In Figure 2b, the area of ​​the passage for the fluid catalyst particles is reduced by 31% by the contact device based on the passage of the riser reactor upstream of the contact device. In both figures, it is clear that the area of ​​the stationary zone (4) is significantly reduced compared to Figure 1.

[0034] Figure 3 shows a contact device (5) which includes a section (5a) made of refractory material connected to the outer metal wall (7) of the riser reactor via a metal structure (5b) passing through the inner wall (6) of the reactor.

[0035] Figure 4 shows different cross-sectional views of the same contact device.

[0036] Figure 5 shows a diagram of the reactor interior, illustrating a contact device (5) that protrudes into the reactor upstream of the feed material injector (1). The flow of fluid catalyst particles (8) passes through the contact device upstream of the injection zone. Within the injection zone, the feed material injector (1) provides hydrocarbon feed material, which comes into contact with the fluid catalyst particles.

[0037] Examples The following non-limiting embodiments are provided for further explanation of the present invention.

[0038] The present invention was tested using computational fluid dynamics (CFD) simulations. The models were configured to represent a standard riser reactor configuration and process conditions. The same basic riser reactor and process conditions were used for each overview, except for the modifications described for each overview. Four different overviews were modeled. Overview 1 (basic case; comparison) simulated an unmodified riser reactor. Overview 2 added a contact device upstream of the feed material injector. Overview 3 (comparison) involved a reduction in the diameter of the riser reactor upstream of the feed nozzle. Overview 4 adapted Overview 3 by adding a contact device upstream of the feed nozzle. The simulation results are shown in Table 1.

[0039] [Table 1]

[0040] Summary 2 clearly demonstrated that adding a contact device upstream of the feed nozzle increased the vaporization of the feed material by more than 2 wt% through better contact between the injected oil and the high-temperature fluid catalyst in these simulations compared to Summary 1. Part of this improvement, though not all, can be achieved by replacing the lower section of the riser tube with one having a smaller diameter (Summary 3). However, the addition of a contact device (e.g., Summary 2) does not require replacement of the lower section of the riser tube and can be added to existing reactors.

[0041] Further advantages were demonstrated by combining a smaller lower riser tube with a contact device (Summary 4). The embodiments are described below. Appearance 1 A catalytic cracking reactor comprising a conduit configured to allow the passage of a catalyst particle flow, and an injection zone including a ring of a feed material injector extending inward from the wall of the reactor and angled to inject feed material into the catalyst particle flow, wherein the reactor also comprises a contact device projecting into the reactor from the inner wall of the reactor upstream of the injection zone. Appearance 2 The catalytic decomposition reactor according to embodiment 1, wherein the contact device includes a composite material of a refractory material and a metal structure. Appearance 3 A catalytic cracking reactor according to embodiment 1 or 2, wherein the distance between the downstream end of the contact device and the upstream end or lower side of the material injector is 25 inches (63.5 cm) or less. Pattern 4 A catalytic cracking reactor according to any one of embodiments 1 to 3, wherein the cross-sectional area of ​​the catalyst particle flow is reduced by at least 10% and 35% or less, based on the cross-sectional area of ​​the reactor upstream of the contact device. Appearance 5 The catalytic cracking reactor according to any one of embodiments 1 to 4, wherein the reactor is an ascending tube reactor configured to allow the catalyst particle flow to pass upward. Appearance 6 A method for mixing a flow of fluid catalyst particles with a hydrocarbon supply material, wherein the method is a) A step of generating a flow of fluid catalyst particles in a reactor, b) A step of passing the fluid catalyst particle flow through a contact device protruding from the inner wall of the reactor into the reactor, c) Next, the fluid catalyst particle flow is passed through an injection zone including a ring of a feed material injector extending inward from the wall of the reactor, bringing the hydrocarbon feed material provided through the feed material injector into contact with the fluid catalyst particle flow. d) A method comprising the step of passing the fluid catalyst particle stream, which has been in contact with a hydrocarbon supply material, through the downstream section of the reactor to convert the hydrocarbon supply material into a conversion product in the presence of the catalyst particles. Appearance 7 The method according to embodiment 6, wherein the hydrocarbon stream contains high-boiling hydrocarbons, and the conversion product contains heating oil, gasoline, or lighter hydrocarbons that boil in the lighter range.

Claims

1. A catalytic cracking reactor comprising a conduit configured to allow the passage of a catalyst particle flow, and an injection zone including a ring of a feed material injector extending inward from the reactor wall and angled to inject feed material into the catalyst particle flow, wherein the reactor also comprises a contact device projecting into the reactor from the inner wall of the reactor upstream of the injection zone, A catalytic cracking reactor in which the contact device comprises an annular element having an outer diameter equal to the inner diameter of the reactor.

2. The catalytic decomposition reactor according to claim 1, wherein the contact device includes a composite material of a refractory material and a metal structure.

3. The catalytic cracking reactor according to claim 1 or 2, wherein the distance between the downstream end of the contact device and the upstream end or lower side of the material injector is 25 inches (63.5 cm) or less.

4. The catalytic cracking reactor according to any one of claims 1 to 3, wherein the cross-sectional area of ​​the catalyst particle flow is reduced by 10% to 35% based on the cross-sectional area of ​​the reactor upstream of the contact device.

5. The catalytic cracking reactor according to any one of claims 1 to 4, wherein the reactor is an ascending tube reactor configured to allow the catalyst particle flow to pass upward.

6. A method for mixing a flow of fluid catalyst particles with a hydrocarbon supply material, wherein the method is a) A step of generating a fluid catalyst particle flow in a reactor, b) A step of passing the fluid catalyst particle flow through a contact device that protrudes from the inner wall of the reactor into the reactor and comprises an annular element having an outer diameter equal to the inner diameter of the reactor, c) Next, the fluid catalyst particle flow is passed through an injection zone including a ring of a feed material injector extending inward from the wall of the reactor, bringing the hydrocarbon feed material provided through the feed material injector into contact with the fluid catalyst particle flow. d) A method comprising the step of passing the flow of fluid catalyst particles, which has been in contact with a hydrocarbon supply material, through the downstream section of the reactor to convert the hydrocarbon supply material into a conversion product in the presence of the catalyst particles.

7. The method according to claim 6, wherein the hydrocarbon stream contains high-boiling hydrocarbons, and the conversion product contains heating oil, gasoline, or lighter hydrocarbons that boil in the lighter range.

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