RU145365U1 - REACTOR FOR HETEROGENEOUS CATALYTIC PROCESS - Google Patents

Abstract

1. A reactor for carrying out a heterogeneous catalytic process in one or more moving catalyst beds arranged one above the other with a radial course of the reaction stream, including a vertical cylindrical body, a cover and a bottom, fittings for introducing and discharging the reaction stream, fittings for introducing and discharging catalyst particles into a reactor, a hopper in the upper part of the reactor with a supply of fresh catalyst and a storage hopper for spent catalyst in the lower part of the reactor, one or more each other above the catalyst layers, bounded by an annular catalyst basket, consisting of permeable partitions on the side, and impermeable partitions, vertically arranged tubes for feeding the catalyst under the influence of gravity between the hoppers and / or catalyst layers, above and below, characterized in that each catalyst basket it is bounded above and below by an impenetrable partition having a conical shape in a vertical section. 2. The reactor according to claim 1, characterized in that the said impermeable partitions consist of two surfaces located at an angle of 60-100 ° .3. The reactor according to claim 1, characterized in that the ratio of the height of the catalyst layer to the diameter of the central axial channel of the catalyst basket does not exceed h / d≤10, and the ratio of this height to the transverse distance of the annular channel between the wall of the reactor and the catalyst basket does not exceed h / L≤40.

Description

The utility model relates to the field of processes and apparatuses of chemical technology and can be used to carry out a catalytic heterogeneous process, in particular, catalytic reforming of petroleum products in a moving catalyst bed.

Catalytic reforming of petroleum products is one of the main refining processes and is designed to produce high-octane components of motor fuel. Modern catalytic reforming processes utilize continuous catalyst regeneration technology. For this purpose, various designs of reactors with a catalyst bed moving under the influence of gravity and a radial course of the reaction stream are used. Particles of fresh catalyst enter the upper part of the reaction zone, pass through it, deactivating, then are removed from the reaction zone, regenerate, and then again enter the upper part of the working catalyst layer.

A number of designs of catalytic reactors with a moving catalyst bed and a radial course of the reaction stream are known (US 3706536, B01J 9/12, 12/19/1972; US 3854887, B01J 9/12, 12/17/1974; US 4040794, B01J 8/12, 08/09/1977 ; US 4135886, B01J 8/12, 01/23/1979; US 4167553, B01J 8/12, 09/11/1979; US 4411869, B01J 8/12, 10/25/1983; US 4411870, B01J 8/12, 10/25/1983; US 4567023, B01J 8/12, 01/28/1986; US 4869808, C10G 23/00, 09/26/1989). In these structures, one or more catalyst layers are made in the form of a ring elongated in the vertical direction. The lateral surface of the layer is limited by perforated cylindrical walls. The top of the layer is closed with a flat cover, through which fresh catalyst flows into the layer through the feed tubes under the influence of gravity. Such a choice of the shape of the top of the layer determines the general disadvantage of these reactors. When fresh catalyst is introduced, hills of particles are formed on the surface of the layer, located under the feed tubes. Accordingly, voids free of catalyst particles form in the space between the tubes above the bed. This creates the possibility of a slip of the unreacted reaction mixture in these places of the layer, which can lead to a deterioration of the technical and economic characteristics of the process. To compensate for this effect in some of these reactor designs, the lateral perforated walls bounding the layer do not have perforation in a certain area at the top of the layer, which allows creating a “shut-off” inoperative catalyst layer that prevents its hydraulic resistance bypassing the flow in the upper part of the layer.

In the known design of a moving bed reactor (US 4277444, B01J 8/00, 07/07/1981), the lid bounding the upper part of the layer is made of inclined walls, one of which has perforation for the passage of the reaction stream. This embodiment of the moving layer also has a drawback similar to the above structures. When the catalyst is introduced with a finite number of feed tubes, voids will appear in the upper part of the bed through which the flow will be bypassed. Execution with perforation of one of the inclined walls of the lid will enhance this negative effect.

A known reactor design (US 5130106, B01J 8/12, 07/14/1992) with a radial layer of a moving catalyst, in which the joint of the supply tubes with the top cover is made in the form of expanding cones, selected as a prototype. This eliminates the possibility of the formation of voids in the upper part of the layer and reduces the bypassing of the reaction stream. At the same time, this design is not without other drawbacks. Thus, the reaction stream is introduced into the reactor through a side flange in the reactor vessel into the free space above the catalyst layer, and a mixture of raw materials and catalytic reaction products from the catalyst layer is discharged from the reactor through a curved pipe passing through the indicated free space. Since when the catalytic reforming process is implemented in such a reactor design, the temperature difference between the inlet and the outlet stream can reach 100 ° C, the presence of a “cold” branch pipe in the indicated space will lead to local temperature inhomogeneities in the inlet stream and at the inlet to the catalyst layer. It can also degrade the control of the catalytic process by temperature readings at certain points at the inlet / outlet of the reactor.

In addition, in the reactor design under consideration, the lower boundary of the layer is formed by a flat bottom, through holes in which deactivated catalyst particles are removed from the layer. This leads to the formation of stagnant zones in the lower part of the moving layer, in which the deactivated catalyst particles can remain for a long time, forming conglomerates of coked particles.

In the descriptions of all the reactor designs discussed above, no influence of the conditions of supply / withdrawal of the reaction stream from the layer formed by the geometry of the axial and annular channels formed by the radial catalyst layer and the reactor vessel was also noted. It is known that these parameters can have a significant effect on the distribution of the reaction flow in the bed (IE Idelchik. Aerohydrodynamics of technological apparatuses. M. Mashinostroenie, 1983, pp. 293-308) and on the characteristics of the catalytic process as a whole.

The utility model solves the problem of designing a reactor with a moving bed of catalyst particles and a radial course of the reaction stream, which ensures the maximum possible uniform distribution of the reaction stream in the catalyst bed, eliminates the likelihood of bypassing the flow through possible voids in the bed, and ensures that all catalyst particles are removed from the moving bed to regeneration.

The objective is achieved by the fact that the proposed reactor design for carrying out a heterogeneous catalytic process in a moving catalyst bed, consisting of a vertical cylindrical body with fittings for input and output of the reaction stream, a cover and a bottom with fittings placed on them for input and output of catalyst particles into the reactor, hopper in the upper part of the reactor with a supply of fresh catalyst and a storage tank for spent catalyst in the lower part of the reactor, one or more, located one above on the other hand, catalyst beds bounded by an annular catalyst basket consisting laterally of permeable baffles, and above and below from impermeable baffles, vertically arranged catalyst supply tubes under the influence of gravity between the hoppers and / or catalyst layers. These impermeable partitions of the catalyst basket, bounding the catalyst layer above and below, consist of each of two plates forming a conical shape in a vertical section at an angle α = 60 ÷ 100 °. The preferred value is α = 60 °, with this value of the cone opening angle there are guaranteed to be no voids in the upper and lower parts of the catalyst basket and stagnant zones in the moving layer. To ensure uniform distribution of the reaction flow in the bed, the ratio of the height of the catalyst bed to the diameter of the central axial channel of the catalyst basket should not exceed h / d≤10, and the ratio of the specified layer height to the transverse distance of the annular channel between the wall of the reactor and the catalyst basket should not exceed h / L≤40.

The technical result of the claimed utility model is that the selected reactor design, in particular the design of the upper and lower covers of the catalyst basket in the form of a cone with the stated opening angle a, eliminates the formation of voids in the upper and lower parts of the moving layer and prevents bypassing the reaction stream in the layer In addition, this provides the conditions for the withdrawal of all catalyst particles from the moving layer. Limitations of the ratio of the height of the catalyst layer to the diameter of the central axial channel of the catalyst basket h / d≤10 and the ratio of the indicated height to the transverse distance of the annular channel between the wall of the reactor and the catalyst basket h / L≤40 make it possible to ensure uniform distribution of the reaction flow in the catalyst layer. Together, these new properties of the utility model make it possible to carry out the catalytic process at the optimum parameters, reaching the maximum possible indicators for obtaining the target product. In addition, they can improve operational properties by ensuring the circulation of all catalyst particles through the reactor.

The essence of the utility model is illustrated in Fig., Which shows in section a reactor with a moving catalyst bed for conducting a heterogeneous catalytic process.

The reactor for carrying out a heterogeneous catalytic process consists of a vertical cylindrical body 1, a cover 2 and a bottom 3, fittings for introducing an initial gas mixture 4 and outputting end products 5, fittings for introducing fresh catalyst 6 and withdrawing spent catalyst 7, hopper 8 with a fresh catalyst reserve , bounded below by a bottom 9 of a conical shape, of tubes 10 for supplying a catalyst under the influence of gravity, one or more, one above the other, catalyst layers 11 bounded by an annular a catalyst basket consisting of permeable side walls 12, and above and below, of impermeable walls 13 and 14, having a conical shape, an impenetrable wall 15 connecting the basket to the reactor vessel, an impenetrable wall 16, tubes 17 for feeding the catalyst under the influence of gravity from the catalyst bed to the output hopper 18.

The reactor operates as follows.

Fresh catalyst through the nozzle 6 enters the hopper 8 of the reactor, where it is evenly distributed through the tubes 10. Moving under the influence of gravity through the tubes 10, the catalyst particles enter the catalyst bed 11, pass the catalyst basket from top to bottom and through the tubes 17 enter the outlet hopper 18 and then through the pipe 7 are removed from the reactor for regeneration. The reaction stream enters the reactor through the pipe 4, passes into the center of the catalyst basket and through the permeable baffle 12 enters the catalyst layer 11, moving in the radial direction from the center to the walls of the reactor. Next, the mixture of catalytic reaction products and raw materials through the permeable baffle 12 enters the annular space formed by the wall of the reactor 1 and the catalyst basket, and is discharged from the reactor through the pipe 5.

This design of the reactor, in particular, the implementation of the catalyst basket with a cone-shaped in vertical section cover and bottom, ensures that the particles of the catalyst move uniformly throughout the volume without voids affecting the distribution of the reaction stream. It also provides conditions for the withdrawal of all catalyst particles from the catalyst basket and their circulation through the reactor. These conditions are guaranteed to be satisfied when the angle of opening of the conical cover and bottom α = 60 ° and are also satisfied in the range α = 6 ÷ 100 °. When α <60 °, the height of the catalyst basket becomes relatively large, which leads to the irrational use of the reactor volume, which, as a rule, operates under high overpressure, and an unreasonable increase in the cost of the reactor. With a value of α> 100 °, when the particles of the catalyst move in the upper part of the catalyst basket, voids with a high probability can occur through which the unreacted feed is skipped (bypassed).

A uniform distribution of the reaction flow in the moving catalyst bed is achieved by selecting the geometric dimensions of the inlet and outlet channels formed by the side walls of the catalyst basket and the reactor vessel. The inlet channel, located along the vertical axis of the reactor, is formed by the inner permeable wall of the catalyst basket, has the shape of a cylinder open at the top and muffled at the bottom with a horizontal impenetrable partition. The diameter of the inlet channel d coincides with the inner diameter of the catalyst basket, and the height h coincides with the height of the cylindrical part of the specified basket. The output channel is formed by the reactor vessel and the outer permeable wall of the catalyst basket, has the shape of a ring, blanked from above by a horizontal impenetrable partition and open from below. The height of the outlet channel h coincides with the height of the cylindrical part of the catalyst basket, and the transverse distance L of the channel is determined by the diameters of the reactor vessel and the catalyst basket. The condition of uniform flow distribution in the catalyst bed is achieved while the conditions for the input and output channels are satisfied and is satisfied when the ratio of the height of the input channel to the diameter h / d≤10 and the ratio of the height of the output channel to the transverse distance h / L≤40. For values of h / d≥10 and h / L≥40, elongated, relatively thin channels are obtained, the pressure distribution in which is uneven in length, which causes uneven distribution of the reaction stream in the catalyst bed.

Claims (3)

1. A reactor for carrying out a heterogeneous catalytic process in one or more moving catalyst beds arranged one above the other with a radial course of the reaction stream, including a vertical cylindrical body, a cover and a bottom, fittings for introducing and discharging the reaction stream, fittings for introducing and discharging catalyst particles into a reactor, a hopper in the upper part of the reactor with a supply of fresh catalyst and a storage hopper for spent catalyst in the lower part of the reactor, one or more each other above the catalyst layers, bounded by an annular catalyst basket, consisting of permeable partitions on the side, and impermeable partitions, vertically arranged tubes for feeding the catalyst under the influence of gravity between the hoppers and / or catalyst layers, above and below, characterized in that each catalyst basket bounded above and below by an impenetrable partition having a vertical section in a conical shape. 2. The reactor according to claim 1, characterized in that the said impermeable partitions consist of two surfaces located at an angle of 60-100 °. 3. The reactor according to claim 1, characterized in that the ratio of the height of the catalyst layer to the diameter of the central axial channel of the catalyst basket does not exceed h / d≤10, and the ratio of this height to the transverse distance of the annular channel between the wall of the reactor and the catalyst basket does not exceed h / L≤40.