RU2283174C1 - Reactor for maintaining catalytic processes - Google Patents

Abstract

FIELD: chemical industry.

SUBSTANCE: reactor can be used for performing heterogeneous catalytic reactions of hydrocarbons. Reactor has case, cap and bottom, couplings for introducing initial gas mixture and outputting final product, gas-proof horizontal partition onto which partition the motionless layer of granulated particles of catalyst is disposed. Additional internal wall is disposed inside reactor to have space with case. Wall is made of sheet material. Top part of wall is connected with case and its lower part is connected with gas-proof partition. Additional internal wall has height being higher than top border of catalyst's layer. It also has a number of holes disposed higher than top border of catalyst layer. There is one more row of holes is disposed in lower part of wall to provide passage of part of reaction flow through space between case of reactor and additional internal wall. Distribution unit is mounted onto input coupling which has ring-shaped input channel, central axially symmetric channel, several branch pipes which connect the channels; branch pipes are disposed in tangent to mentioned output channel; there is also baffle disc provided. Method allows homogenous mixing of two-phase flow before letting it in reactor and uniform distributing it onto catalyst layer.

EFFECT: reduced loss through walls of reactor.

3 cl, 3 dwg

Description

The invention relates to the field of processes and apparatuses of chemical technology and can be used to carry out heterogeneous catalytic reactions, including the processes of selective conversion of hydrocarbons in oil refining processes.

It is known that the effectiveness of a catalytic heterogeneous process depends on the nature of the distribution of technological parameters in the catalyst bed. To create optimal conditions for the process, it is necessary to ensure uniform flow distribution at the inlet to the catalyst bed. This problem becomes especially relevant in the case of a two-phase (liquid-gas) inlet flow, which occurs for many processes of refining petroleum products, such as hydrotreatment. To create these conditions, special designs of flow distributors are used, which are installed at the inlet of the reactor in front of the catalyst bed. In addition, it is necessary to create an optimal temperature distribution in the layer. As a rule, this is a given temperature gradient along the length of the layer, which is organized by various methods of supplying or removing heat along the length of the layer. A uniform temperature distribution in the cross sections of the layer is provided by reducing heat loss through the walls of the reactor.

Known designs of distributors of the input stream, which work quite effectively in the case of a single-phase flow [C. Setterfield. Practical course of heterogeneous catalysis. M .: "World", 1984, p. 404]. When distributing a two-phase gas-liquid flow, such structures, as a rule, do not provide a uniform distribution of both components of the reaction stream.

Traditionally, in oil refining, devices made in the form of the so-called. cap grids [G.L. Vikhman, S.A. Kruglov. Fundamentals of designing apparatuses and machines of oil refineries. M., Mechanical Engineering, 1978. P. 230]. This device is characterized by comparative simplicity of design and low hydraulic resistance. Known modifications to cap grids [RF Patents No. 2192303, B 01 J 8/02, 10/10/2002; No. 2206383, B 01 J 8/00, 06/20/2003]. A common disadvantage of this type of switchgear is the discrete nature of the introduction of the liquid phase into the catalyst bed due to the finite number of holes through which the liquid component of the stream overflows onto the underlying layer. In addition, the effectiveness of such a device is critical to its installation in a reactor. Slight deviations from the horizontal location lead to the flow of fluid along the surface of the cap lattice to a reduced area and the predominant flow of fluid into the layer at this location.

There are known designs of catalytic reactors in which heat loss through the reactor walls is achieved by installing an additional wall inside the reactor, placed with a gap to the main wall, and passing the entire reaction stream through the gap [RF Patent No. 2070827, B 01 J 8/04, 12/27/27] . The latter limits the possibility of optimizing the temperature regime in the catalyst bed due to the inability to adjust the flow rate.

The closest in number of similar features to the claimed one is a reactor for carrying out catalytic processes [RF Patent No. 1594755, B 01 J 8/02, 11/20/1996]. The reactor has a housing, a fitting for introducing the initial reaction mixture and outputting the target product, a gas-permeable partition on which the catalyst layer is placed, a switchgear installed at the inlet of the reactor. The distribution device consists of a nozzle placed axially in the reactor, sealed from below and having side windows for introducing hydrocarbon feedstocks and a tangentially placed horizontal nozzle for introducing water vapor. A perforated disk is placed below the nozzle for introducing hydrocarbon raw materials.

The known design of the reactor has limitations in application, due to the fact that for a high-quality distribution of the reaction mixture, two flows must be fed into the reactor, one of which, in this case, water vapor, must have a relatively large energy reserve for axial swirling and distribution of flow over the cross section of the reactor.

The invention is aimed at achieving homogeneous mixing of a two-phase stream at the inlet of the reactor and its uniform distribution on the catalyst layer, reducing heat loss through the walls of the reactor and supplying additional heat to the lower part of the catalyst layer. This makes it possible to ensure the conduct of endothermic reactions under conditions close to optimal, and almost completely eliminate the occurrence of inhomogeneities of the two-phase flow in the catalyst bed.

This result is achieved in that the reactor for carrying out heterogeneous catalytic reactions, in particular reactions of selective conversion of hydrocarbons in oil refining, includes a housing, a cover and a bottom, fittings for introducing the initial gas mixture and outputting the target product, a gas-permeable horizontal partition on which a layer of granular particles is located catalyst, an additional inner wall made of sheet metal, the upper part of which is connected, is installed inside the reactor with a gap to the body with a housing, and the lower part with a gas-permeable partition, the additional inner wall having a height above the upper boundary of the catalyst layer and has a number of holes located above the upper boundary of the catalyst layer and a number of holes located in its lower part to ensure the passage of the reaction fraction flow through the gap between the reactor vessel and the additional inner wall, a distribution device is installed at the inlet fitting, consisting of an input channel of a circular shape, a central axisymmetric egg output channel, several channels connecting these nozzles arranged tangentially to said output channel, and the baffle disc.

A series of holes in the lower part of the additional wall is located at a height of up to 0.3 of the height of the catalyst layer, mainly 0.1-0.15 of the indicated height.

The specified connecting pipes are arranged in height, mainly from 1 to 3 rows, and the ratio of the length of the connecting pipes to their transverse size is not less than 2.

The baffle plate of the switchgear is located horizontally with a height gap from the lower cut of the specified central axisymmetric output channel.

Figure 1 shows a sectional view of a reactor for conducting heterogeneous catalytic reactions, in particular reactions of selective conversion of hydrocarbons.

Figure 2 on an enlarged scale shows a fragment of the reactor, comprising a catalyst layer, the outer and inner walls of the reactor.

Figure 3 shows the switchgear mounted on the inlet fitting.

A reactor for carrying out heterogeneous catalytic reactions, in particular reactions of selective transformations of hydrocarbons, consists of a housing 1, a cover 2 and a bottom 3, fittings for introducing the initial gas mixture 4 and outputting the target product 5, a horizontal gas-permeable partition 6, on which the catalyst layer 7 is placed, an inner wall 8 having an upper 9 and lower 10 row of holes for passage of a part of the reaction mixture, an annular channel 11 at the inlet of the distribution device 12, connecting pipes 13, the output channel 14, located axisymmetrically in the reactor, the baffle plate 15, attached to the switchgear 12 racks 16.

The reactor operates as follows. The flow of the initial mixture of gas and liquid enters the reactor through the inlet 4 and the distribution device 12. Passing through the annular channel 11 and the tangentially arranged connecting pipes 13, the flow acquires an axial swirl in the outlet channel 14, disperses by increasing the flow velocity and then, flowing around the fender the disk 15 is distributed evenly over the cross section of the reactor. Next, the main part of the stream passes through the catalyst bed 7, and a small part of the stream passes through the upper row of holes 9 into the annular gap formed by the reactor vessel 1 and the inner wall 8, and then through the lower row of holes 10 in the wall 8 enters the lower part of the catalyst layer 7 Such partial bypassing of the gas phase of the stream provides additional thermal insulation of the catalyst layer and the supply of additional heat to the lower part of the layer. This is of great importance in the case of carrying out endothermic reactions to optimize the temperature profiles in the catalyst bed and increase the yield of the target product. After passing through the layer 7, the flow passes through the gas-permeable partition 6 and extends beyond the reactor through the outlet 5.

Claims (4)

1. A reactor for carrying out catalytic processes, including heterogeneous catalytic reactions of hydrocarbons, including a housing, a cover and a bottom, a fitting for introducing an initial gas mixture and outputting a target product, a gas-permeable horizontal partition on which a layer of granular catalyst particles is located, characterized in that an additional inner wall made of sheet metal is installed inside the reactor with a gap to the vessel, the upper part of which is connected to the vessel, and the lower part to gas permeability my partition, while the additional inner wall has a height above the upper boundary of the catalyst layer and has a number of holes located above the upper boundary of the catalyst layer, and a number of holes located in its lower part, to ensure the passage of a fraction of the reaction stream through the gap between the reactor vessel and the additional a distribution wall consisting of an input channel of a circular shape, a central axisymmetric output channel, several connections nayayushchie these channels nozzles located tangentially to the specified output channel, and the jack disc. 2. The reactor according to claim 1, characterized in that the series of holes in the lower part of the additional wall is located at a height of up to 0.3 of the height of the catalyst layer, mainly 0.1-0.15 of the specified height. 3. The reactor according to claim 1, characterized in that the said connecting pipes are arranged in height mainly from 1 to 3 rows, and the ratio of the length of the connecting pipes to their transverse size is at least 2. 4. The reactor according to claim 1, characterized in that the baffle plate is located horizontally with a clearance in height from the lower cut of the specified Central axisymmetric output channel.

Images