CN212680961U

CN212680961U - Alkylation reactor

Info

Publication number: CN212680961U
Application number: CN202021969836.XU
Authority: CN
Inventors: 江闽; 桑立强
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-09-10
Filing date: 2020-09-10
Publication date: 2021-03-12
Anticipated expiration: 2030-09-10

Abstract

The utility model discloses an alkylation reactor. The reactor comprises a shell, wherein the bottom of the shell is provided with a hydrocarbon reactant inlet, the top of the shell is provided with a hydrocarbon reactant outlet, and an HF circulating conveying area, a mixed reaction area, a centrifugal separation area and a gravity separation area which are sequentially communicated are arranged in the shell from bottom to top; wherein, the inside of the shell is provided with a vertical central shaft, the bottom end of the central shaft is arranged in the HF circulation conveying area, and the top end of the central shaft is arranged in the centrifugal separation area. The utility model provides an alkylation reactor can make HF completely at reactor internal recycle, need not to carry out solitary separation and transport in the equipment outside to reduce HF's conveying equipment and pipeline by a wide margin, also reduced HF's use amount simultaneously. Therefore, the construction cost and the operation cost of the alkylation reaction system can be greatly reduced, and the potential safety hazard of HF in the circulating conveying process can be reduced.

Description

Alkylation reactor

Technical Field

The utility model relates to a chemical industry equipment field, in particular to alkylation reactor.

Background

In the production of alkylbenzene, HF, i.e. hydrogen fluoride gas, is generally used as a catalyst for alkylation reaction, wherein the reactants are benzene and olefin, and the reaction product is alkylbenzene. In the traditional process, reactants and a catalyst are generally mixed and reacted outside a reactor through a static mixer, then the reactants and the catalyst enter a heat exchanger for cooling, and then the reactants and the catalyst enter the reactor for full reaction; then the reaction product and the catalyst enter a horizontal separation tank, the polar HF solution and the nonpolar hydrocarbon mixture are separated by gravity, and the separated HF is conveyed to a static mixer by an acid pump and can be recycled.

In the above conventional process, HF circulates outside the reactor and is required to pass through a series of apparatuses such as a separation tank, an acid pump, a mixer, a heat exchanger, and a reactor in order. And HF is a strong corrosive medium with extreme harm and is easy to cause larger potential safety hazard, so that the HF has higher requirements on the materials and the sealing of equipment, pipelines, valves and the like in the conveying process, and particularly has higher requirements on impellers and sealing of pump equipment. And thus the production costs of the corresponding device are high.

SUMMERY OF THE UTILITY MODEL

In order to solve the problem, the utility model provides an alkylation reactor.

According to one aspect of the utility model, an alkylation reactor is provided, which comprises a shell, wherein the bottom of the shell is provided with a hydrocarbon reactant inlet, the top of the shell is provided with a hydrocarbon reactant outlet, and the inside of the shell is provided with an HF circulation conveying area, a mixed reaction area, a centrifugal separation area and a gravity separation area which are sequentially communicated from bottom to top; wherein, the inside of the shell is provided with a vertical central shaft, the bottom end of the central shaft is arranged in the HF circulation conveying area, and the top end of the central shaft is arranged in the centrifugal separation area.

In some embodiments, the bottom of the housing has a skirt, and the hydrocarbon reactant inlet is disposed in a sidewall of the skirt. The skirt is thus able to support the entire reactor and is not in communication with the upper regions thereof.

In some embodiments, an HF circulation suction inlet is arranged around the lower end of the HF circulation conveying area, and a circulation pump shell is arranged inside the HF circulation conveying area; the bottom end of the central shaft is arranged in the circulating pump shell, and a circulating pump driving impeller and a circulating pump driven impeller are arranged at the bottom end of the central shaft. Thus, the hydrocarbon reactant composed of the alkane olefin and the benzene can be mixed with the HF in the HF circulation conveying area and further enter the mixed reaction area together.

In some embodiments, the mixing reaction zone is divided into an inner cylinder located at the inner side and an outer cylinder located at the outer side, and the bottom end and the top end of the inner cylinder are respectively communicated with the HF circulation conveying zone and the centrifugal separation zone. Therefore, the inner cylinder in the mixed reaction area is used for mixing and reacting, and the outer cylinder is used for refluxing HF discharged after the reaction to the HF circulating conveying area.

In some embodiments, a plurality of vertical cooling heat exchange tubes are arranged between the outer cylinder and the inner cylinder, a cooling water inlet is arranged at the lower end of the outer side wall of the outer cylinder, and a cooling water outlet is arranged at the upper end of the outer side wall of the outer cylinder. Therefore, cooling water can be circularly introduced into the outer cylinder through the cooling water inlet and the cooling water outlet, and the HF in the outer cylinder is cooled through the cooling heat exchange tube.

In some embodiments, the centrifugal separation zone is internally provided with a spiral guide plate which is arranged on a central shaft, and the side surface of the centrifugal separation zone is provided with a plurality of guide holes; wherein the top end of the central shaft is installed inside the centrifugal separation zone. Thus, the majority of the HF can be separated off by means of a centrifugal separation zone, the mixture of residual hydrocarbons and a small portion of HF entering the gravitational separation zone.

In some embodiments, the bottom end of the central shaft is mounted inside the HF circulating transport zone by a lower bearing and a lower bearing support, and the top end of the central shaft is mounted inside the centrifugal separation zone by an upper bearing and an upper bearing support. Thus, a specific mounting position and manner of the central shaft are provided, which is mainly used for mounting the impeller for stirring.

In some embodiments, a plurality of stirrer assemblies are mounted side by side on the central shaft at the mixing reaction zone, and the stirrer assemblies comprise a stirrer impeller and a stirrer baffle plate. Thus, the hydrocarbon reactant composed of the alkane and the benzene and the HF as the catalyst can be sufficiently mixed and reacted by the stirring of the plurality of stirrer units.

Drawings

FIG. 1 is a schematic diagram of an alkylation reactor according to an embodiment of the present invention;

FIG. 2 is a schematic view of the HF circulation transfer zone of FIG. 1;

FIG. 3 is a schematic view of a part of the structure of the mixing reaction zone shown in FIG. 1;

FIG. 4 is a schematic view of a part of the centrifugal separation region shown in FIG. 1.

In the figure: the device comprises a shell 1, a hydrocarbon reactant inlet 2, a hydrocarbon reactant outlet 3, an HF circulating conveying area 4, a mixing reaction area 5, a centrifugal separation area 6, a gravity separation area 7, a central shaft 8, a stirrer assembly 9, a skirt 11, an HF circulating suction inlet 41, a circulating pump shell 42, a circulating pump driving impeller 43, a circulating pump driven impeller 44, an inner cylinder 51, an outer cylinder 52, a cooling heat exchange pipe 53, a cooling water inlet 54, a cooling water outlet 55, a spiral guide plate 61, a guide hole 62, a lower bearing 81, a lower bearing support 82, an upper bearing 83, an upper bearing support 84, a stirrer impeller 91 and a stirrer baffle plate 92.

Detailed Description

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

Fig. 1 schematically shows the structure of an alkylation reactor according to an embodiment of the present invention, fig. 2 shows the structure of an HF circulation transfer zone in fig. 1, fig. 3 shows the structure of a mixed reaction zone in fig. 1, and fig. 4 shows the structure of a centrifugal separation zone in fig. 1. As shown in fig. 1-4, the alkylation reactor comprises a housing 1, the housing 1 being generally cylindrical in shape and vertically disposed throughout, and the components of the reactor being integrated into the housing 1. The reactor and the interface of each component thereon can be made of flange, thread, or welding, and can be made of appropriate metal material or nonmetal material (such as various impellers and guide plates) as required.

The bottom of the shell 1 is provided with a hydrocarbon reactant inlet 2, the top is provided with a hydrocarbon reactant outlet 3, and the inside is sequentially provided with an HF circulating conveying area 4, a mixed reaction area 5, a centrifugal separation area 6 and a gravity separation area 7 from bottom to top. Wherein, the hydrocarbon reactant inlet 2 is communicated with an HF circular conveying area 4, the HF circular conveying area 4 and a centrifugal separation area 6 are communicated with the inner side of a mixed reaction area 5, the centrifugal separation area 6 is communicated with a gravity separation area 7, and the gravity separation area 7 is communicated with the hydrocarbon reactant outlet 3.

A vertical central shaft 8 is also installed inside the housing 1, the bottom end of the central shaft 8 is installed in the HF circulation transfer section 4, the top end is installed in the centrifugal separation section 6, and impellers and other stirring structures are installed at various positions on the central shaft 8.

Preferably, a skirt 11 is provided at the bottom of the shell 1, the skirt 11 being capable of supporting the upper structure of the alkylation reactor. Wherein the hydrocarbon reactant inlet 2 is arranged on the side wall of the skirt 11, and the skirt 11 is not communicated with the HF circulating conveying area 4 and the like.

The bottom of the HF circulation transfer region 4 is communicated with the hydrocarbon reactant inlet 2, a plurality of HF circulation suction ports 41 are provided around the lower end of the HF circulation transfer region 4, and the HF circulation suction ports 41 can suck HF (hydrogen fluoride gas) distributed in the alkylation reactor into the HF circulation transfer region 4. And a circulating pump shell 42 is arranged in the HF circulating and conveying area 4, the bottom end of the central shaft 8 is arranged in the circulating pump shell 42, a circulating pump driving impeller 43 and a circulating pump driven impeller 44 are fixedly arranged at the bottom end of the central shaft 8, and when gas is introduced into the HF circulating and conveying area 4 from the hydrocarbon reactant inlet 2, the circulating pump driving impeller 43 and the circulating pump driven impeller 44 can be driven to rotate, so that the central shaft 8 is driven to rotate together.

Preferably, a lower bearing 81 is coupled to the bottom end of the central shaft 8, a lower bearing support 82 is coupled to the lower bearing 81, and the lower bearing support 82 is mounted on the inner wall of the circulation pump housing 42. The lower bearing 81 is composed of a rolling bearing and a thrust bearing, the thrust bearing mainly bears the static load generated by the central shaft 8 and other components fixed on the central shaft 8, and the rolling bearing is used for fixing the axial position of the central shaft 8.

The mixing reaction zone 5 is mainly divided into an inner cylinder 51 and an outer cylinder 52, the inner cylinder 51 is located inside the outer cylinder 52, i.e. the inner cylinder 51 is located inside the mixing reaction zone 5, and the outer cylinder 52 is located outside the mixing reaction zone 5, i.e. the shell 1 of the part of the reactor. Wherein, the lower end of the inner cylinder 51 extends and is communicated with the HF circulation conveying area 4, the upper end extends and is communicated with the centrifugal separation area 6, and the HF circulation suction inlet 41 is specifically arranged on the lower end of the inner cylinder 51.

The central shaft 8 passes through the inner cylinder 51 of the mixing reaction zone 5, and a plurality of stirrer assemblies 9 are uniformly arranged in parallel at the middle section of the inner cylinder 51, namely, the position between the circulating conveying zone 4 and the centrifugal separation zone 6, wherein each stirrer assembly 9 comprises a stirrer impeller 91 and a stirrer baffle plate 92, and can fully stir and mix various substances in the inner cylinder 51.

And a plurality of cooling heat exchange tubes 53 are distributed and mounted in the outer cylinder 52 and the inner cylinder 51 of the mixing reaction zone 5, and each cooling heat exchange tube 53 is vertically arranged and is spaced from each other by a certain distance. And the lower end of the outer side wall of the outer cylinder 52 is provided with a cooling water inlet 54, the upper end of the outer side wall is provided with a cooling water outlet 55, cooling water is introduced from the cooling water inlet 54, and flows out from the cooling water outlet 55 after passing through each cooling heat exchange pipe 53, so that HF in the outer cylinder 52 can be cooled.

The centrifugal separation section 6 mainly includes an upper end of the inner cylinder 51, and the top end of the central shaft 8 is installed inside the upper end of the inner cylinder 51 of the centrifugal separation section 6. Wherein, the inside of the centrifugal separation area 6, namely the inside of the upper end of the inner cylinder 51 is provided with a spiral guide plate 61, and the spiral guide plate 61 is fixedly arranged on the central shaft 8; and a plurality of guide holes 62 are formed in the side surface of the centrifugal separation region 6, i.e., the upper end side surface of the inner cylinder 51.

Preferably, an upper bearing 83 is connected to the top end of the central shaft 8, and an upper bearing support 84 is connected to the upper bearing 83, and the upper bearing support 84 is mounted on the inner wall of the top end of the central shaft 8. The upper bearing 83 is also composed of a rolling bearing and a thrust bearing, the thrust bearing mainly bears static loads generated by the central shaft 8 and other components fixed on the central shaft 8, and the rolling bearing is used for fixing the axial position of the central shaft 8.

The gravity separation zone 7 is provided with gravity separation equipment, so that the hydrocarbon reaction products and HF can be separated under the action of gravity, and a stable two-phase interface is formed. Wherein the gravity separation device can be selected in the prior art according to actual conditions.

When the alkylation reactor is used for reaction operation, HF is introduced into the alkylation reactor, a hydrocarbon reactant consisting of alkane olefin and benzene is input into the alkylation reactor from a hydrocarbon reactant inlet 2, the hydrocarbon reactant flows through an HF circulation conveying area 4, a mixed reaction area 5, a centrifugal separation area 6 and a gravity separation area 7 from bottom to top in sequence, and the final reaction product is a hydrocarbon mixture consisting of alkylbenzene, alkane and benzene and is discharged from a hydrocarbon reaction product outlet at the top of the reactor. The specific process is as follows.

The hydrocarbon reactant composed of alkane olefin and benzene firstly enters the circulating pump shell 42 of the HF circulating and conveying area 4 and flows from bottom to top in the circulating pump shell 42, the circulating pump is pushed to drive the impeller 43 to rotate, and then the central shaft 8 is driven to rotate, the circulating pump drives the impeller 44 to rotate and rotates along with the central shaft 8, a downward attraction force is generated, HF in the reactor is sucked into the bottom end of the lower cylinder in the HF circulating and conveying area 4 from the HF circulating suction port 41, and the hydrocarbon reactant is mixed with the sucked HF and enters the mixed reaction area 5. Wherein the density difference of the fluid between the inner cylinder 51 and the outer cylinder 52 also provides a part of the motive force for the entry of HF.

Then, inside the middle section of the lower cylinder in the mixing reaction zone 5, the stirrer assembly 9 is driven by the central shaft 8 to rotate, and the hydrocarbon reactant and the HF are fully mixed under the action of the stirrer assembly 9. Under the action of catalyst HF, the alkane and olefin react with benzene to produce alkylbenzene, which may form some excessive alkane and benzene, which are mixed to form hydrocarbon mixture and the hydrocarbon mixture and HF are fed into the centrifugal separating area 6.

Then, inside the upper end of the lower cylinder in the centrifugal separation zone 6, the spiral guide plate 61 is driven by the central shaft 8 to rotate, and the mixture entering the spiral guide plate 61 forms centrifugal flow under the action of the spiral guide plate 61. Under the action of centrifugal force, HF with higher density is accumulated on the inner wall of the inner cylinder body 51, and most of HF is discharged along the diversion holes 62 on the side wall of the inner cylinder body 51; the hydrocarbon mixture with lower density accumulates in the center of the inner cylinder 51 of the reactor and enters the gravity separation zone 7 with a small part of HF along the axial direction from the top of the inner cylinder 51 of the reactor.

Then, in the gravity separation zone 7, a small portion of HF gradually separates from the hydrocarbon mixture under the action of gravity and forms a stable two-phase interface. And finally, discharging the fully separated hydrocarbon mixture out of the reactor from a hydrocarbon reaction product outlet at the top of the reactor.

Wherein, most HF discharged from the centrifugal separation zone 6 enters between the outer cylinder 52 and the inner cylinder 51 of the mixed reaction zone 5, enters into each cooling heat exchange tube 53, and exchanges heat with cooling water outside the cooling heat exchange tubes 53, thereby taking away heat generated in the reaction process and realizing the cooling effect. The cooled HF can flow to the lower part of the mixed reaction zone 5 and is sucked into the HF circulating and conveying zone 4 again by the HF circulating suction port 41, thereby realizing the recycling. Further, the cooled HF can exchange heat with the ongoing reaction in the inner cylinder 51 to transfer the reaction heat in time for controlling the reaction temperature.

Furthermore, the power source for the rotation of the central shaft 8 comes from the power generated by the flow of the hydrocarbon reactant entering the reactor, and when the flow rate of the hydrocarbon reactant entering the reactor is reduced, the rotation speed of the central shaft 8 is reduced accordingly, and the circulation amount of HF pushed by the shaft circulation pump driven impeller 44 is reduced accordingly. Therefore, by controlling the flow speed and the flow of the fed hydrocarbon reactant, the reactant and the catalyst HF can be automatically mixed according to a certain proportion.

The utility model provides an alkylation reactor compares with traditional alkylation reaction equipment, has following advantage:

1) the method integrates mixing, reaction, separation and catalyst circulation, so that HF completely circulates in the reactor, and independent separation and conveying are not required outside the device, thereby greatly reducing conveying equipment and pipelines of the HF, and simultaneously reducing the usage amount of the HF, so that the construction cost and the operation cost of an alkylation reaction system can be greatly reduced, and the potential safety hazard of the HF in the circulating conveying process is reduced;

2) external force driving is not needed, mechanical seal is not needed to be arranged on a rotating part, the equipment structure is simple, and manufacturing and installation are convenient;

3) the equal proportion mixing of the catalyst and the reactant can be automatically realized, and no additional flow regulation facility is needed;

4) the loss of mechanical energy is small, the kinetic energy of the high-pressure fluid can be efficiently converted into the kinetic energy of the low-pressure fluid, the loss of mechanical energy of HF in the circulating conveying process is effectively reduced, and the energy consumption is reduced;

5) the catalyst HF and the reactant are fully mixed by adopting a stirring mode, the mixing effect is better than that of a static mixer in the traditional system, and the reaction efficiency is improved;

6) the separation effect of the centrifugal separation method for separating HF and hydrocarbon mixture is far better than that of a gravity separator in a traditional system, so that the size of separation equipment can be greatly reduced, the usage amount of HF is reduced, the occupied area of the system is reduced, and the investment and the operation and maintenance cost of the equipment are reduced;

7) besides being applied to alkylation reaction, the catalyst can also be applied to other various heterogeneous catalytic reaction systems;

8) simple structure, area is little, is applicable to the transformation to current device.

What has been described above are only some embodiments of the invention. For those skilled in the art, without departing from the inventive concept, several modifications and improvements can be made, which are within the scope of the invention.

Claims

1. An alkylation reactor, comprising: the device comprises a shell (1), wherein a hydrocarbon reactant inlet (2) is formed in the bottom of the shell (1), a hydrocarbon reactant outlet (3) is formed in the top of the shell, and an HF circulating conveying area (4), a mixed reaction area (5), a centrifugal separation area (6) and a gravity separation area (7) which are sequentially communicated are formed in the shell (1) from bottom to top; wherein, the inside of the shell (1) is provided with a vertical central shaft (8), the bottom end of the central shaft (8) is arranged in the HF circulation conveying area (4), and the top end is arranged in the centrifugal separation area (6).

2. An alkylation reactor according to claim 1, wherein: the bottom of the housing (1) has a skirt (11) and the hydrocarbon reactant inlet (2) is provided in the side wall of the skirt (11).

3. An alkylation reactor according to claim 1, wherein: an HF circulation suction port (41) is arranged around the lower end of the HF circulation conveying area (4), and a circulation pump shell (42) is installed inside the HF circulation conveying area (4); wherein the bottom end of the central shaft (8) is mounted inside the circulation pump housing (42), and the bottom end of the central shaft (8) is mounted with a circulation pump driving impeller (43) and a circulation pump driven impeller (44).

4. An alkylation reactor according to claim 1, wherein: the mixed reaction zone (5) is divided into an inner cylinder (51) positioned at the inner side and an outer cylinder (52) positioned at the outer side, and the bottom end and the top end of the inner cylinder (51) are respectively communicated with the HF circulating conveying zone (4) and the centrifugal separation zone (6).

5. An alkylation reactor according to claim 4, wherein: the outer barrel (52) and the inner barrel (51) are provided with a plurality of vertical cooling heat exchange tubes (53), the lower end of the outer side wall of the outer barrel (52) is provided with a cooling water inlet (54), and the upper end of the outer side wall of the outer barrel (52) is provided with a cooling water outlet (55).

6. An alkylation reactor according to claim 1, wherein: a spiral guide plate (61) is arranged in the centrifugal separation area (6), the spiral guide plate (61) is arranged on a central shaft, and a plurality of guide holes (62) are formed in the side surface of the centrifugal separation area (6); wherein the top end of the central shaft (8) is mounted inside the centrifugal separation zone (6).

7. An alkylation reactor according to claim 1, wherein: the bottom end of the central shaft (8) is arranged inside the HF circulation conveying area (4) through a lower bearing (81) and a lower bearing support (82), and the top end of the central shaft (8) is arranged inside the centrifugal separation area (6) through an upper bearing (83) and an upper bearing support (84).

8. An alkylation reactor according to claim 7, wherein: a plurality of stirrer assemblies (9) are arranged on the part, located in the mixing reaction zone (5), of the central shaft (8) side by side, and each stirrer assembly (9) comprises a stirrer impeller (91) and a stirrer baffle plate (92).