Multi-section fixed bed reactor

Abstract

The invention relates to the technical field of fixed bed reactors, and discloses a multi-section fixed bed reactor, which comprises a reactor body and a plurality of catalyst bed layers connected in series, a multi-stage flow guide element is arranged at a fault transition section between adjacent catalyst bed layers, and the multi-stage flow guide element comprises a flow guide cone, a honeycomb type rectification sieve plate and an adjustable petal distributor; the flow guide cone is fixed at the inlet of the inter-section transition section and is coaxially mounted with the reactor body, and a spiral flow guide groove is formed in the cone surface of the flow guide cone; the honeycomb type rectification sieve plate is arranged at the bottom of the flow guide cone, the honeycomb type rectification sieve plate is composed of honeycomb units, and a micro flow guide fin is embedded in each honeycomb unit; the flow guide cones, the honeycomb type rectification sieve plates and the adjustable petal distributors are sequentially arranged on the fault transition sections of the adjacent catalyst bed layers, so that uniform distribution of fluid is realized, the flow guide cones buffer the fluid and guide the fluid to flow along the spiral flow guide grooves, and a preliminary dispersion effect is achieved.

Description

Technical Field

[0001] The present invention relates to a fixed bed reactor, and more particularly to a multi-stage fixed bed reactor. Background Art

[0002] A multi-stage fixed bed reactor is composed of a plurality of catalyst beds connected in series, and the temperature is adjusted by heat exchange or quench fluid between sections. However, when the fluid is redistributed in the inter-stage transition section, due to flow inertia and structural design limitations, the following problems are likely to occur:

[0003] 1. Excessively high local flow velocity: The catalyst particles are eroded and worn, and the service life is shortened;

[0004] 2. Areas with low flow velocity: Side reactions increase (such as coking), and selectivity decreases;

[0005] 3. Reduction of overall efficiency: The utilization rate of the catalyst is uneven, and the conversion rate fluctuates.

[0006] In the prior art, it is difficult to achieve fine control of the flow field by using a single deflector or a static distributor, and there are large pressure drop losses and poor adaptability. Summary of the Invention

[0007] The present invention provides a multi-stage fixed bed reactor to solve the problems such as short catalyst life, many side reactions and low efficiency caused by uneven flow velocity.

[0008] The technical solution is as follows:

[0009] A multi-stage fixed bed reactor includes a reactor body and a plurality of catalyst beds connected in series. A multi-stage flow guiding element is provided in the inter-stage transition section between adjacent catalyst beds. The multi-stage flow guiding element includes a flow guiding cone, a honeycomb-shaped rectifying sieve plate and an adjustable petal-shaped distributor; the flow guiding cone is fixed at the entrance of the inter-stage transition section and is coaxially installed with the reactor body. A spiral flow guiding groove is provided on the conical surface of the flow guiding cone; the honeycomb-shaped rectifying sieve plate is arranged at the bottom of the flow guiding cone. The honeycomb-shaped rectifying sieve plate is composed of a plurality of honeycomb units, and each honeycomb unit is embedded with a micro flow guiding fin; the adjustable petal-shaped distributor is arranged at the bottom of the honeycomb-shaped rectifying sieve plate, and the adjustable petal-shaped distributor has a plurality of blades with adjustable opening angles.

[0010] Further, the flow guiding cone includes an expanding conical guiding body and a contracting inverted frustum-shaped shell. Among them, the outside of the contracting inverted frustum-shaped shell is fixed on the inner wall of the reactor body. A support frame is provided at the bottom of the contracting inverted frustum-shaped shell, and a vertical shaft is provided at the center of the support frame. The expanding conical guiding body is installed at the upper end of the vertical shaft. The expanding conical guiding body, the contracting inverted frustum-shaped shell and the rotating shaft are coaxial, and the lower half part of the expanding conical guiding body extends into the contracting inverted frustum-shaped shell.

[0011] Further, a plurality of spiral flow guiding grooves are respectively arranged on the side wall of the gradually expanding conical flow guiding body and the inner side wall of the gradually contracting inverted frustum shell, and the groove depth of the spiral flow guiding groove is 2-3 mm.

[0012] Further, the cross-section of the honeycomb unit is a regular hexagon.

[0013] Further, the micro flow guiding fins are trapezoidal thin plates, and three micro flow guiding fins are arranged in each honeycomb unit, and the three micro flow guiding fins form a trident shape.

[0014] Further, the adjustable petal distributor further includes an annular shell, a hinge mechanism, a central rotating shaft and an adjusting mechanism. Among them, a plurality of the blades are respectively hinged to the annular shell through a central rotating shaft, and a hinge mechanism is arranged at one end of each central rotating shaft. The adjusting mechanism includes a driving ring coaxially arranged on the outer ring of the annular shell and a motor arranged on one side of the annular shell. The driving ring is respectively connected to each hinge mechanism through a lever, an arc-shaped tooth is arranged on the outer side of the driving ring, a gear is arranged at the output shaft end of the motor, and the gear meshes with the arc-shaped tooth.

[0015] Further, inclined grooves are arranged on the surface of the blade.

[0016] Further, the reactor further includes a pressure sensor and a laser Doppler velocimeter. The pressure sensor is arranged at the top of the catalyst bed for monitoring the inter-stage pressure difference; the laser Doppler velocimeter is arranged in the inter-stage transition section and is wirelessly connected to the motor.

[0017] The beneficial effects of the present invention are as follows:

[0018] In the present invention, the fluid is evenly distributed by sequentially arranging a flow guiding cone, a honeycomb rectifying sieve plate and an adjustable petal distributor in the inter-stage transition section between adjacent catalyst beds. Among them, the flow guiding cone buffers the passing fluid and guides the fluid to flow along the spiral flow guiding groove, playing a preliminary dispersion role. Then, the fluid enters the honeycomb sieve plate, and the local eddy currents can be separated through a plurality of honeycomb units and the embedded micro flow guiding fins, so that the flow velocities in each area are balanced and the fluid is further divided. In addition, by arranging the petal distributor, when the fluid passes through the opening and closing blades, it can flow out evenly, and the flow velocity is controlled by controlling the opening and closing angle of the blades. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the reactor of the present invention.

[0020] Figure 2 It is a schematic structural diagram of the flow guiding cone of the present invention.

[0021] Figure 3 It is a schematic structural diagram of the flow guiding cone from another perspective of the present invention.

[0022] Figure 4 This is a schematic structural view of the honeycomb rectifying sieve plate petal distributor of the present invention.

[0023] Figure 5 This is an enlarged view of the honeycomb unit and the micro-guide fins of the present invention.

[0024] Figure 6 This is a schematic structural view of the adjustable petal distributor in the closed state of the blades of the present invention.

[0025] Figure 7 This is a schematic structural view of the adjustable petal distributor in the open state of the blades of the present invention.

[0026] Names and serial numbers of components in the figure: 1 - reactor body, 2 - catalyst bed, 3 - flow guide cone, 31 - spiral flow guide groove, 3a - gradually expanding conical flow guide body, 3b - gradually shrinking inverted frustum shell, 4 - honeycomb rectifying sieve plate, 41 - honeycomb unit, 42 - micro-guide fins, 5 - adjustable petal distributor, 51 - blades, 511 - inclined groove, 52 - circular ring-shaped shell, 53 - hinge mechanism, 54 - central rotating shaft, 55 - driving ring, 56 - motor, 57 - dial rod, 58 - arc-shaped teeth, 59 - gear. Specific embodiments

[0027] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "front", "rear", "left", "right", "upper", "lower", "inner", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of description and does not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. For the convenience of understanding the present invention, the present invention will be further described below with reference to the drawings.

[0028] Such as Figure 1The multi-stage fixed bed reactor shown comprises a reactor body 1 and a plurality of catalyst beds 2 connected in series, and a multi-stage flow-guiding element is provided in the intermittent transition section between adjacent catalyst beds 2, and the multi-stage flow-guiding element comprises a flow-guiding cone 3, a honeycomb-type rectifying sieve plate 4 and an adjustable petal distributor 5; wherein an inlet is arranged at the top of the reactor body 1, and an outlet is arranged at the bottom, and the fluid is introduced through the inlet, passes through a plurality of catalyst beds 2, the flow-guiding cone 3, the honeycomb-type rectifying sieve plate 4 and the adjustable petal distributor 5 in sequence, and is discharged from the outlet. In this embodiment, the flow-guiding cone 3 is fixed at the inlet of the inter-stage transition section, and the distance H1=0.5D between the front end of the flow-guiding cone 3 and the outlet of the upstream catalyst bed 2, wherein D is the diameter of the reactor; the flow-guiding cone 3 and the reactor body are spaced apart by a distance of 1.5D. 1 is coaxially installed, and the cone surface of the guide cone 3 is provided with a spiral guide groove 31; the spiral guide groove 31 can guide the flow direction of the fluid and realize the speed reduction buffer; the honeycomb rectifying screen plate 4 is arranged at the bottom of the guide cone 3, and the honeycomb rectifying screen plate 4 is composed of honeycomb units 41, and each honeycomb unit 41 is embedded with a micro-guide fin 42, and the micro-guide fin 42 can divide the large-scale vortex to make it maintain the degree of turbulence, which has the function of dissipating kinetic energy, and the micro-guide fin 42 can further divert the flow to make the fluid more uniform; the adjustable petal distributor 5 is arranged at the bottom of the honeycomb rectifying screen plate 4, and the adjustable petal distributor 5 is composed of a plurality of blades 51 with adjustable opening and closing angles. The blades 51 with adjustable opening and closing angles can not only control the flow rate of the fluid, but also further uniformize the fluid.

[0029] refer to Figures 2-3 In a specific embodiment, the guide cone 3 includes a gradually expanding conical guide body 3a and a gradually contracting inverted frustum shell 3b, wherein the outer side of the gradually contracting inverted frustum shell 3b is fixed to the inner wall of the reactor body 1 through a flange, and the upper and lower parts of the gradually contracting inverted frustum shell 3b are open, and the fluid enters from the upper opening and flows out from the lower opening. A support frame 32 is arranged at the bottom of the gradually contracting inverted frustum shell 3b, and the specific support frame 32 is composed of three rod-shaped structures in an annular array, and a vertical axis 33 is arranged at the center of the support frame 32. The lower end of the vertical shaft 33 is rotatably connected to the support frame 32 through a bearing, and a gradually expanding conical guide body 3a is arranged at the upper end of the vertical shaft 33. In addition, the gradually expanding conical guide body 3a, the gradually contracting inverted frustum shell 3b and the rotating shaft 33 are coaxial, and the overall size of the gradually expanding conical guide body 3a is smaller than the gradually contracting inverted frustum shell 3b. The lower half of the gradually expanding conical guide body 3a extends into the gradually contracting inverted frustum shell 3b, and a gap for fluid to pass through is formed between the gradually expanding conical guide body 3a and the gradually contracting inverted frustum shell 3b.

[0030] After the fluid passes through the catalyst bed 2, it flows into the diversion cone 3. After contacting the surface of the gradually expanding conical fluid guide 3a, it flows along the surface of the gradually expanding conical fluid guide 3a, and then flows to the inner surface of the gradually contracting inverted frustum shell 3b and flows downward along the inner surface. After passing through the gap between the two, it flows to the honeycomb rectifying sieve plate 4. To further improve the dispersion effect of the fluid, several spiral diversion grooves 31 are respectively arranged on the side wall of the gradually expanding conical fluid guide 3a and the inner side wall of the gradually contracting inverted frustum shell 3b. The spiral direction of the spiral diversion grooves 31 is consistent with the fluid flow direction. The groove depth is between 2-3 mm, and the spiral angle α is between 10-15°. The spiral diversion grooves 31 can induce the circumferential velocity component, preliminarily homogenize the flow field, and reduce the flow velocity peak value.

[0031] In addition, it should also be noted that since the gradually expanding conical fluid guide 3a is a conical structure, when the local high-speed eddy current impacts the surface of the gradually expanding conical fluid guide 3a, the fluid will flow along the surface generatrix direction. Since the spiral diversion grooves 31 are arranged on its surface, when the eddy current impacts the side wall of the spiral diversion grooves 31, it will cause the gradually expanding conical fluid guide 3a to rotate along the vertical axis 33. This not only plays a role in buffering and dissipation to a certain extent, but also enables the fluid to flow uniformly to the surface of the gradually contracting inverted frustum shell 3b, further realizing dispersion.

[0032] Reference Figures 4-5 Referring to

[0033] Reference Figures 6-7, in a specific embodiment, it is installed at H3 = 0.2D at the bottom of the honeycomb rectifying sieve plate 4. The adjustable petal distributor 5 further includes an annular housing 52, a hinge mechanism 53, a central rotating shaft 54 and an adjusting mechanism. Among them, a plurality of the blades 51 are respectively hinged to the annular housing 52 through a central rotating shaft 54. The annular housing 52 is fixed to the inner wall of the reactor body 1 through fasteners. Specifically, in this embodiment, a plurality of blades 51 are circumferentially distributed along the inner circle of the annular housing 52. The blades 51 are triangular. All the blades 51 are butted together to cover the inner circle of the annular housing 52. A cylinder is also provided at the center of the annular housing 52. The cylinder is fixed to the annular housing 52 through a connecting rod. One end of the blade 51 is hinged to the side wall of the cylinder through a central rotating shaft 54, and the other end is hinged to the annular housing 52 through a central rotating shaft 54. The central rotating shaft 54 at this end penetrates the side wall of the annular housing 52 and extends outward and is connected with a hinge mechanism 53. By moving the hinge mechanism 53, the central rotating shaft 54 can be driven to rotate by a certain angle, and then the blade 51 can be driven to rotate along the central rotating shaft 54. When the blade 51 is at a 0-degree angle, the blade closes the opening of the annular housing 52, preventing the fluid from passing through. When the blade 51 rotates by a certain angle, the fluid will pass through the opening gap of the blade 51. The function of the adjusting mechanism is to control the rotation angle of the blade 51 by controlling the movement of the hinge mechanism 53. Among them, the adjusting mechanism includes a driving ring 55 coaxially arranged on the outer circle of the annular housing 52 and a motor 56 arranged on one side of the annular housing 52. The inner diameter of the driving ring 55 is larger than the outer diameter of the annular housing 52. A venturi-shaped abutting wheel is arranged between the two. By arranging the abutting wheel, the position of the driving ring 55 can be restricted without affecting the rotation of the driving ring 55. A dial rod 57 corresponding to the hinge mechanism 53 one by one is arranged on the inner side of the driving ring 55. A slotted hole is formed on the hinge mechanism 53. One end of the dial rod 57 is inserted into the slotted hole. By rotating the driving ring 55, the dial rod 57 is driven to move synchronously, further driving the hinge mechanism 53 to rotate and swing along the central rotating shaft 54.

[0034] Furthermore, an arc-shaped tooth 58 is arranged on the outer side of the driving ring 55, and a gear 59 is arranged at the output shaft end of the motor 56. The gear 59 meshes with the arc-shaped tooth 58. By driving the gear 59 to rotate by the motor, the arc-shaped tooth 58 and the driving ring 55 are driven to rotate.

[0035] The rotation angle of the drive ring 55 controls the rotation angle of the central rotating shaft 54. The adjustable range of the opening and closing angle γ of its blades 51 is between 0° and 60°, the number of blades 51 is between 8 and 12, and inclined grooves 52 are provided on the surface of the blades 51. Specifically, the inclined grooves 52 are provided on the side in contact with the fluid. In a specific embodiment, the groove width of the inclined grooves 52 is 0.5 mm, the depth is 1 mm, and the spacing is 2 mm. By controlling the opening and closing angle of the blades 51, the inter-stage flow velocity and non-uniformity can be adjusted to achieve dynamic adjustment and improve the adaptability of the reactor.

[0036] Furthermore, the reactor further includes a pressure sensor and a laser Doppler velocimeter (not shown in the figure). The pressure sensor is arranged at the top of the catalyst bed 2 for monitoring the inter-stage pressure difference; the laser Doppler velocimeter (LDV) is arranged in the inter-stage transition section and is wirelessly connected to the motor 56. Specifically, the laser Doppler velocimeter is installed at the entrance of the inter-stage transition section of the catalyst bed 2 and is connected to the motor 56 by wireless connection; the motor adjusts the opening and closing angle γ of the blades according to the flow velocity data real-time fed back by the LDV. The pressure sensor array is arranged at the top of the catalyst bed 2 and is wirelessly connected to the control system. The control system drives the motor 56 to adjust the opening and closing angle γ of the blades based on the pressure difference data, and controls the flow rate deviation rate to be less than or equal to 2%.

[0037] The dynamic regulation method of the adjustable petal distributor 5 includes the following steps:

[0038] ⅰ Monitor the inter-stage pressure difference in real time through the pressure sensor array;

[0039] ⅱ Drive the motor to adjust the opening and closing angle γ of the blades based on the pressure difference data;

[0040] ⅲ Maintain the inter-stage flow velocity non-uniformity ≤ ±3% and the flow rate deviation rate ≤ 2%.

[0041] Using this reactor, the problem of excessively high local flow velocity during the redistribution of the fluid in the inter-stage transition section can be effectively adjusted, and further flow splitting can be carried out to reduce the non-uniformity of the fluid.

[0042] The above embodiments only represent the preferred embodiments of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations, improvements and substitutions can be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. A multi-stage fixed-bed reactor, comprising a reactor body (1) and a number of serially connected catalyst beds (2), wherein a multi-stage flow guiding element is provided in the break transition section between adjacent catalyst beds (2), and is characterized in that, The multi-stage flow guiding element includes a flow guiding cone (3), a honeycomb-shaped rectifying sieve plate (4), and an adjustable petal distributor (5); The flow guiding cone (3) is fixed at the inlet of the inter-stage transition section and is coaxially installed with the reactor body (1). The conical surface of the flow guiding cone (3) is provided with spiral flow guiding grooves (31); The honeycomb-shaped rectifying sieve plate (4) is arranged at the bottom of the flow guiding cone (3). The honeycomb-shaped rectifying sieve plate (4) is composed of a plurality of honeycomb units (41), and each honeycomb unit (41) is embedded with a micro flow guiding fin (42); The adjustable petal distributor (5) is arranged at the bottom of the honeycomb-shaped rectifying sieve plate (4). The adjustable petal distributor (5) has a plurality of blades (51) with adjustable opening and closing angles.

2. The multi-stage fixed bed reactor according to claim 1, wherein: The flow guiding cone (3) includes an expanding conical fluid guide (3a) and a contracting inverted frustum shell (3b). Among them, the outer side of the contracting inverted frustum shell (3b) is fixed on the inner wall of the reactor body (1). A support frame (32) is arranged at the bottom of the contracting inverted frustum shell (3b). A vertical shaft (33) is arranged at the center of the support frame (32). The expanding conical fluid guide (3a) is installed at the upper end of the vertical shaft (33). The expanding conical fluid guide (3a), the contracting inverted frustum shell (3b), and the rotating shaft (33) are coaxial. The lower half of the expanding conical fluid guide (3a) extends into the contracting inverted frustum shell (3b).

3. The multi-stage fixed bed reactor according to claim 2, wherein: The side wall of the expanding conical fluid guide (3a) and the inner side wall of the contracting inverted frustum shell (3b) are respectively provided with several spiral flow guiding grooves (31). The groove depth of the spiral flow guiding grooves (31) is 2-3 mm.

4. The multi-stage fixed bed reactor according to claim 1, characterized in that: The cross-section of the honeycomb unit (41) is a regular hexagon.

5. The multi-stage fixed bed reactor according to claim 4, wherein: The micro flow guiding fin (42) is a trapezoidal thin sheet. Three micro flow guiding fins (42) are arranged in each honeycomb unit (41), and the three micro flow guiding fins (42) form a trident shape.

6. The multi-stage fixed bed reactor according to claim 1, characterized in that: The adjustable petal distributor (5) further includes an annular shell (52), a hinge mechanism (53), a central rotating shaft (54), and an adjusting mechanism. Among them, a plurality of the blades (51) are respectively hinged to the annular shell (52) through a central rotating shaft (54). One hinge mechanism (53) is arranged at one end of each central rotating shaft (54). The adjusting mechanism includes a driving ring (55) coaxially arranged on the outer ring of the annular shell (52) and a motor (56) arranged on one side of the annular shell (52). The driving ring (55) is respectively connected to each hinge mechanism (53) through a shift lever (57). An arc-shaped tooth (58) is arranged on the outer side of the driving ring (55). A gear (59) is arranged at the output shaft end of the motor (56). The gear (59) meshes with the arc-shaped tooth (58).

7. The multi-stage fixed-bed reactor according to claim 6, characterized in that: The surface of the blade (51) is provided with an inclined groove (511).

8. The multi-stage fixed bed reactor according to claim 7, characterized in that: The reactor further includes a pressure sensor and a laser Doppler velocimeter. The pressure sensor is arranged at the top of the catalyst bed (2) for monitoring the inter-stage pressure difference. The laser Doppler velocimeter is arranged in the inter-stage transition section and is wirelessly connected to the motor (56).

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