KR101672601B1 - Dehydogenation reactor - Google Patents

Abstract

The present invention relates to a dehydrogenation reactor for carrying out a catalytic hydrocarbon process wherein the reactor of the annular housing is surrounded by a catalyst bed in which the central region is fixed by inner and outer screens. The central region and the radial catalyst bed are surrounded by an annular region that accommodates the heat exchange means.

Description

[0001] DEHYDOGENATION REACTOR [0002]

The present invention relates to a dehydrogenation reactor useful for gas phase conversion of various hydrocarbon feedstocks, and more particularly to a dehydrogenation reactor comprising two or more annular reaction zones spaced vertically in a long reactor housing, Lt; / RTI >

The dehydrogenation reaction, such as dehydrogenation of propane with propylene and isobutane with isobutene, produces olefins which are more reactive than alkane feedstocks and which are easier to form coke, at relatively high temperatures used for dehydrogenation. Coke formation on the catalyst causes catalyst deactivation and decreases product yield. Coke formation in the reactor or downstream device can lead to increased reactor pressure and clogging causing reactions such as additional coke formation and methane formation, again reducing useful product yield and causing shutdown of the apparatus for coke removal.

The dehydrogenation reaction is highly endothermic and requires a large amount of heat transfer to the catalyst bed. A shorter residence time is desirable to prevent the olefin product from reacting further to produce coke, but in conventional systems, an increase in olefin production rate increases the endothermic burden of the reactor, lowering the temperature much faster and lowering the product yield, Which requires a shorter cycle time or additional interstage heating, which is not practical.

The dehydrogenation reactor is an elongated columnar vertical structure with a diameter of about 5 to 30 feet and a length of 10 to 100 feet or more. The general structure of such a reactor can be injected into the inlet located at the bottom center of the vertical reactor, where the gas flows up through the annular zone and passes radially outward through a porous catalyst bed or other suitable dehydrogenation catalyst Passes upwardly through the outer annular zone to be discharged at the top of the outer periphery of the reactor. Because the reactant gas flow through the catalyst bed is radial, such reactors are often referred to as "spinning" reactors. Also, because of the flow characteristics over an extended vertical length of the reactor, which longitudinal or axial flow converts to radial or transverse flow and then back to vertical flow, this reactor also has a flow rate through the catalyst bed from top to bottom Is widely varied in a conventional reaction vessel, so that the catalyst life is reduced in the region of the reactor having the highest flow rate. The lowest feed rate through the catalyst bed in the radial reactor generally occurs near the top of the reactor and the fastest rate through the catalyst bed occurs near the bottom of the reactor near the feed pipe, as evidenced by experiment and flow measurements. The rate of increase at the bottom of the catalyst bed and the rate of decrease at the top of the catalyst bed greatly shortens the life of the catalyst near the bottom of the reactor and is much faster than the usual expectation of the pause of the reactor for catalyst regeneration.

U.S. Patent Nos. 4,714,592, 4,230,669, 5,250,270 and 5,585,074 disclose spinning reactors. However, the existing techniques disclosed in these patents have a limitation in utilizing the catalyst layer smoothly because the flow stream is composed of a path from the lower portion of the reactor to the outer wall of the reactor through the annular disc-shaped catalyst layer, Also, since the reactor space is used as a discharge channel after the reaction, the product is exposed at a high temperature and the process unit intensity is increased due to the bulk reaction.

It is an object of the present invention to overcome the disadvantages of the prior art described above and to provide a method and apparatus for minimizing the flow velocity deviation between the top and bottom of a reactor, Thereby prolonging the life of the catalyst.

Another object of the present invention is to minimize the variation of the flow velocity in the upper and lower parts of the catalyst layer by utilizing the gas dispersion technique in both the inlet and outlet of the dehydrogenation reactor, thereby making it possible to utilize the catalyst layer uniformly, The purpose is to maximize.

Another object of the present invention is to isolate the lower portion of the reactor from the reaction space to minimize an increase in process unit load due to the bulk reaction.

According to one aspect of the present invention for achieving the above object,

A housing for forming a dehydrogenation reactor, a reactor inlet for supplying a fluid reactant to the inside of the reactor, a reactor radially surrounding the reactor, and a catalyst layer of catalyst particles, And a reactor outlet for withdrawing a reactant stream from within said reactor, said dehydrogenation reactor comprising:

A center gas flow passage is formed in the center of the reactor,

The reactor inlet is formed at an upper end of the reactor,

Wherein the reactor outlet is formed in an upper opening of the reactor,

And a purge gas inlet for injecting a purge gas into the central gas flow passage is formed at a side surface lower side of the reactor opposite to the reactor inlet.

The dehydrogenation reactor of the present invention has a structure in which a reaction flow passes through an inner dispersion plate at an upper end of a reactor, passes through a catalyst layer, and goes to an upper portion of a final reactor. The gas is dispersed by a gas dispersion plate, And passes through the catalyst layer and the double partition wall.

Also, in the upper part of the reactor of the present invention, an annular disc type catalyst heat treatment space is designed to efficiently control the temperature when the catalyst temperature is raised, isolate the lower part of the reactor from the reaction space, purge the space with hydrogen gas, Lt; / RTI >

According to the dehydrogenation reactor of the present invention, the flow velocity difference between the upper and lower portions of the reactor is minimized, and the gas dispersion technique is utilized for both the inlet and the outlet of the reactor to minimize the variation of the flow velocity in the upper and lower parts This makes it possible to maximize the performance of the reactor by making it possible to utilize the catalyst layer evenly.

In addition, the dehydrogenation reactor of the present invention can improve the productivity by minimizing the process unit load increase by bulk reaction by isolating the lower portion of the reactor from the reaction space.

1 is a schematic cross-sectional view of a conventional dehydrogenation reactor.
2 is a schematic cross-sectional view of a dehydrogenation reactor according to an embodiment of the present invention.
3 is a schematic view of a gas distribution plate of a dehydrogenation reactor according to an embodiment of the present invention.
4 is a schematic view for explaining a structure of a double partition wall of a dehydrogenation reactor according to an embodiment of the present invention.

The present invention will now be described in more detail with reference to the accompanying drawings.

Although the terms used in the present invention have been selected as general terms that are widely used at present, there are some terms selected arbitrarily by the applicant in a specific case. In this case, the meaning described or used in the detailed description part of the invention The meaning must be grasped. Like reference numerals designate like elements throughout the specification.

Although the drawings illustrate specific shapes of the dehydrogenation reactor of the present invention, such a dehydrogenation reactor may have various shapes suitable for the specific environment in which it is performed in a particular application, And the like. Moreover, the numbers in the figures represent a simple schematic diagram of the multistep dehydrogenation reactor of the present invention and only the major components are shown. Other pumps, moving pipes, valves, hatches, access outlets, and other similar components have been omitted. The use of such accessories to modify the described dehydrogenation reactor is well known to those skilled in the art and does not depart from the scope and spirit of the appended claims.

As used herein, the term "fluid" means a gas, liquid, or gas or liquid containing a dispersed solid or a mixture thereof. The fluid may be in the form of a gas containing dispersed liquid droplets.

As used herein, the term "reaction zone" refers to the space in the dehydrogenation reactor where the reactants are in contact with the catalyst on the catalyst bed.

The term "screen" in the context of the present invention has a broad meaning, including means suitable for limiting the catalyst to the catalyst bed while allowing flow of the reactant stream across the catalyst bed. Many such screens are known, and since the catalyst particles that descend through the annular catalyst bed are somewhat weak, it is desirable to design such internal and external catalyst holding screens to reduce catalyst wear. Alternatively, the screens may comprise punch plates, perforated plates or perforated pipes. The size of the pores should be such that the flow of reactants through the screen is facilitated, while the passage of the catalyst particles is inhibited. The holes of the perforated plate are formed in the form of a circle, a square, a rectangle, a triangle, a narrow horizontal or vertical slot, and the like. The screens used in the present invention are not limited to cylindrical screens. Moreover, the screens comprise a group of planar plates interconnected to form a catalyst particle retaining structure, such as a cylinder.

2 is a schematic diagram of a dehydrogenation reactor 100 according to the present invention. Referring to FIG. 2, the dehydrogenation reactor 100 according to an embodiment of the present invention includes a housing 20 for forming an interior of a dehydrogenation reactor, a reactor 20 for supplying a high temperature fluid for reducing the catalyst layer, An annular region 25 radially surrounding the reactor core and defined by concentric inner and outer screens 23 and 24 while maintaining a catalyst layer of the catalyst particles 1; And a reactor outlet (27) for withdrawing a reactant stream from the inside of the reactor, wherein a center gas flow passage (28) capable of flowing gas is formed in the center of the reactor, and the reactor inlet (21) Is formed on one side of the upper end of the reactor, the reactor outlet (27) is formed to have an upwardly open structure at the upper end of the reactor, and the reactor inlet And on the side opposite to the bottom, a purge gas inlet 22 for injecting a purge gas to said central gas flow passage 28 is formed.

According to the dehydrogenation reactor of the present invention, the deviation of the catalyst flow velocity in the upper part and the lower part of the reactor can be minimized, and the life of the catalyst can be extended by using the catalyst evenly.

The dehydrogenation reactor of one embodiment of the present invention comprises a catalyst particle capable of being transported as an annular bed through a dehydrogenation reactor by a gravity stream and a dehydrogenation reactor for contacting the reactant stream with a radial stream.

The upper portion of the reaction region of the housing 20 includes a catalyst inlet portion 13 located at an upper portion of the reaction region and connected to the space around the catalyst layer in an open state. This catalyst inlet 13 supplies the catalyst to the catalyst bed in the annular reaction zone.

Referring to FIG. 2, the dehydrogenation reactor 100 is constituted by an outer cylindrical housing 20, and the catalyst layers 25 accommodated therein, i.e., the reaction zones, are radially spaced apart from each other, (28).

The inner and outer screens 23 and 24 formed on the inner and outer sides of the catalyst layer are large enough to allow the fluid flow stream to pass through without any flow resistance or a large pressure drop so that the accommodated catalyst particles 1 can not pass therethrough, And is composed of a screen or a porous body having a mesh size that is sufficiently small.

The reactor feed, ie, the reactants, consisting of hydrocarbons to be treated at a suitable temperature and pressure in the dehydrogenation reactor of the present invention is fed to the annular reaction zone of the dehydrogenation reactor 100 through the reactor inlet 21.

In the dehydrogenation reactor 100 of the present invention, it is also within the scope of the present invention to supply the reactant from the upper side of the dehydrogenation reactor and recover the product stream from the lower side of the dehydrogenation reactor.

An internal dispersion plate 15 for dispersing the catalyst may be installed on the upper end of the dehydrogenation reactor of the present invention. Such a dispersion plate is a structure in which a dispersion plate serving as a catalyst dispersion is composed of a vertical supporter for supporting a dispersion plate in a cylindrical lower part by inverted funnel shape or inverted shape, and these structures are combined.

In the dehydrogenation reactor of the present invention, a gas dispersion plate may be installed outside the catalyst layer to uniformly supply the reactant to the catalyst layer. Referring to FIG. 3, the gas distribution plate 50 is formed of a composite of primary and secondary dispersion plates. In the case of the primary dispersion plate 52, the gas distribution plate 50 is formed into a cylindrical shape with a narrow upper portion And is a porous plate or screen structure so that the fluid can freely travel in the radial direction. In the case of the secondary dispersion plate 51, a structure similar to the primary dispersion plate is formed in a plate or screen structure in which a fluid can pass, and the primary and secondary dispersion plates are connected in a radial direction by partition walls. Depending on the situation, the role of the secondary diffuser plate may replace this role in the outer catalyst layer screen. In FIG. 3, a space partition plate 53 is interposed between the first and second dispersion plates to block the fluid flow in the longitudinal direction of the reactor to smooth the flow of the fluid in the radial direction, thereby uniformizing the fluid flow rate.

The dehydrogenation reactor of the present invention has a structure in which a reaction flow passes through an inner dispersion plate at an upper end of a reactor, passes through a catalyst layer, and goes to an upper portion of a final reactor. The gas is dispersed by a gas dispersion plate, And passes through the catalyst layer and the double partition wall.

4 is a schematic view for explaining a structure of a double partition wall of a dehydrogenation reactor according to an embodiment of the present invention. Referring to FIG. 4, the double partition walls appearing through the catalyst layer are formed by connecting the primary and secondary dispersion plates in the radial direction. The primary dispersion plate 52 is a porous plate or screen structure. The secondary dispersion plate 51) is composed of a blocking film which prevents the fluid from passing therethrough. In FIG. 4, a space partition plate 53 is interposed between the primary dispersion plate and the inner screen 26 to block the fluid flow in the longitudinal direction of the reactor to smooth the fluid flow in the radial direction, .

In addition, in order to efficiently control the temperature when the temperature of the catalyst is raised, an annular disk-shaped heat treatment space is disposed in the upper part of the reactor in the reaction. The heat treatment space 14 of the catalyst layer is formed of a high temperature Of the fluid is introduced into the reactor inlet (11).

In the heat treatment space, the reactants are heated or cooled to a suitable temperature by contact with a heat exchanger (not shown), and the heat transfer medium flowing inside the heat treatment space supplies heat to the process gas or recovers heat from the process gas .

Generally, the heating and cooling means of the present invention comprise a heat exchanger arranged with respect to at least one catalyst bed and, if desired, a gaseous process stream radially entering or exiting the one or more catalyst beds is heated or cooled . In one embodiment, the heat exchange apparatus may be disposed in the reactor central region within the annular portion of the innermost catalyst layer on a single catalyst bed or a series of radially spaced concentric annular catalyst beds.

At the lower end of the reactor 100, there is formed a lower space 40 for separating the reaction space from the reaction space for recycling purge gas to the outlet through the central gas flow passage. In the dehydrogenation reactor of the present invention, since the lower space 40 is isolated from the reaction space, the product can be prevented from being exposed to a high temperature, thereby preventing an increase in process unit intensity due to a bulk reaction.

The dehydrogenation reactor (20) may further include a purge gas injection nozzle (22) installed on the outer circumferential surface to inject purge gas into the central gas flow passage (28). The purge gas is deflected by the deflection plate 30 at the upper part of the reactor and supplied to the catalyst layer 25. [

The lower space 40 of the dehydrogenation reactor 100 is a structure in which the reactant stream passes through the reactor outlet 27 and is deflected by the deflection plate 30 at the upper part of the reactor and supplied to the catalyst layer 25. In the case of the lower space 40, it may be a region heated or cooled by the fluid. The reactant stream leaves the dehydrogenation reactor 100 via the reactor outlet 27 and is sent downstream for further processing. As mentioned above, it is also within the scope of the present invention to recover the reactant stream from the bottom of the dehydrogenation reactor 100 or to recover it from the central region.

The dehydrogenation reaction in the dehydrogenation reactor of the present invention will be described below. As shown in FIG. 2, the hydrocarbon reactant will pass radially through the catalyst bed 25 to convert the hydrocarbon to the desired end product at least partially.

2, although FIG. 2 shows that the reactant is supplied to the central region through the upper portion of the dehydrogenation reactor 100, the lower portion of the dehydrogenation reactor 100 is replaced by the lower portion It is also within the scope of the present invention that the reactants are fed through the reaction zone or the reactants are fed into the outermost annular zone instead of the central zone.

The reactant introduced through the reactor inlet 21 is heated to a suitable temperature in the central region in contact with the heat exchanger and is at least partially converted from the hydrocarbon into the desired end product by passing through the catalyst bed 25 radially past the inner wall . The reactant stream radially emerging from the catalyst layer 25 through the outer screen 24 is sent directly through the outer screen 24 to the annular region where it is the collecting region or the reheating or cooling region or both.

While the invention has been described in connection with various specific embodiments, it is to be understood that various modifications thereof will become apparent to those of ordinary skill in the art upon reading the specification. Accordingly, the invention as described herein is intended to embrace such modifications as fall within the scope of the appended claims.

100: dehydrogenation reactor 10: catalyst hopper
11: reactor inlet 12: catalyst inlet
13: catalyst inlet part 14: catalytic layer heat treatment space
20: reactor housing 21: reactant inlet
22: purge gas inlet 23: inner screen
24: outer screen 25: catalyst layer
28: central gas flow passage 26: reactant outlet passage
27: reactor outlet 30: reactor upper deflection plate
50: gas dispersion plate 29: catalyst outlet
40: lower space 15: internal dispersion plate

Claims (7)

A housing for forming a dehydrogenation reactor, a reactor inlet for supplying a fluid reactant to the inside of the reactor, a reactor radially surrounding the reactor, and a catalyst layer of catalyst particles, And a reactor outlet for withdrawing a reactant stream from within said reactor, said dehydrogenation reactor comprising:
A center gas flow passage capable of flowing gas is formed in the center of the reactor, the reactor inlet is formed at an upper end of the reactor,
A purge gas inlet for injecting a purge gas into the central gas flow passage is formed at a lower side of a side surface of the reactor opposite to the reactor inlet of the reactor, . ≪ / RTI >
The dehydrogenation reactor according to claim 1, wherein an inner dispersion plate for dispersing catalyst is installed at an upper end of the reactor.
The gas distribution plate according to claim 1, wherein a gas dispersion plate is provided outside the catalyst layer to uniformly supply the reactant to the catalyst layer, wherein the gas dispersion plate has a cylindrical shape with a wide upper inlet and a narrow bottom, A primary dispersion plate of a porous structure so that the fluid can freely pass through in the radial direction; A secondary dispersion plate of a porous structure through which fluid can pass; And a space dividing plate disposed between the primary and secondary dispersing plates and interrupting the fluid flow in the longitudinal direction of the reactor to smooth the fluid flow in the radial direction so as to make the fluid flow rate uniform, And the secondary dispersion plate are connected in a radial direction by partition walls.
The dehydrogenation reactor according to claim 1, wherein an annular disc type heat treatment space is provided at an upper portion of the reactor in order to efficiently control the temperature when the temperature of the catalyst is raised.
2. The dehydrogenation reactor according to claim 1, wherein a lower space is formed at a lower end of the reactor to separate from a reaction space formed in connection with the central gas flow passage.
The dehydrogenation reactor according to claim 1, wherein the central gas flow passage is configured to increase the cross-sectional diameter toward the lower end of the reactor.
The dehydrogenation reactor according to claim 1, wherein the dehydrogenation reactor is configured in such a manner that a feed gas passes through a catalyst bed and passes through a double partition wall.

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