A feed distribution device, coal direct liquefaction reactor and operating mode

Abstract

The application discloses a feed distribution device, a coal direct liquefaction reactor and an operation mode, and relates to gas-liquid-solid three-phase feed uniform distribution of the coal direct liquefaction reactor. Two circulating oil feed pipes of the device are arranged at the lower part of a mixing chamber, the outlet centers are separated by 180 degrees in the circumferential direction and are symmetrical about the central axis of the mixing chamber, the nominal diameters of the two pipes are the same and the arrangement modes are the same, so that the single-side momentum input generated by a single bottom circulating oil inlet is changed into balanced input on both sides. The lower part of the annular distribution pipe is provided with circumferentially distributed inclined downward injection holes, the hole diameters are symmetrically and stepwisely increased from the two ends to the middle part along the feed sector to compensate the pressure drop along the pipeline. The downcomer vertically penetrates the mixing chamber along the central axis of the reactor, and the part in the mixing chamber is a straight pipe without an inclined pipe section and a bend. The above structure can reduce the bottom flow deviation and the circumferential flow unevenness, and reduce the risk of deposition and blockage of the solid-containing material at the inclined section or the bending part of the downcomer.

Description

Technical Field

[0001] This invention relates to the field of feed distribution and gas-liquid-solid three-phase flow uniform distribution technology for direct coal liquefaction reactors, and particularly to a feed distribution device with a dual-circulation oil inlet and a central straight downcomer, a direct coal liquefaction reactor, and its operation mode. Background Technology

[0002] Direct coal liquefaction is a process in which a coal-oil slurry composed of pulverized coal, hydrogen-donating solvent, circulating oil, and catalyst undergoes hydrocracking and liquefaction reactions under high temperature, high pressure, and hydrogen-containing gas conditions. The reactor contains gas, liquid, and solid phases simultaneously. The feed rate distribution at the bottom, interphase contact, and particle suspension state affect mass transfer, heat transfer, temperature distribution, and the long-term operation of the unit.

[0003] Traditional structures have only one circulating oil inlet at the bottom of the mixing chamber. When circulating oil is introduced into the mixing chamber from one side through a single inlet, the momentum and flow paths near the inlet differ from those far from the inlet, easily leading to significant unilateral flow and circumferential flow deviation. Simply increasing the inlet pipe diameter cannot eliminate this spatial asymmetry.

[0004] Traditional downcomers are inclined or have their direction changed via bends at the bottom of the mixing chamber. When coal particles and high-viscosity heavy components pass through the inclined pipe section and bend zone, the local resistance increases and a low-velocity backflow zone may be formed. Solid particles are prone to deposit on the inside of the pipe and near the bend, increasing the risk of blockage. Summary of the Invention

[0005] The purpose of this invention is to provide a feed distribution structure that differs from the traditional single-circulation oil inlet and inclined downcomer. By centrally symmetrically arranging the dual-circulation oil inlets, the momentum input on both sides of the bottom of the mixing chamber is balanced, and the central vertical downcomer reduces solid particle retention and blockage.

[0006] To achieve the above objectives, two circulating oil feed pipes are installed below the annular distribution pipe. The outlet centers of the two circulating oil feed pipes are 180° apart circumferentially and symmetrical about the central axis of the mixing chamber. The two pipes have the same nominal diameter, outlet center height, axial inclination angle, and extension length, so that the two circulating oil feed pipes have similar flow resistance and outlet conditions.

[0007] The two reaction feed pipes are also circumferentially spaced 180°±5° apart. The circumferential angle between the first axial plane, which includes the central axis of the mixing chamber and passes through the central axes of the two reaction feed pipes, and the second axial plane, which includes the central axis of the mixing chamber and passes through the central axes of the two circulating oil feed pipes, is 90°±5°, thus forming two sets of orthogonal symmetrical feed directions. Compared with setting the circulating oil inlet only on one side of the bottom, this arrangement does not rely on single pipe diameter expansion, but eliminates the structural root cause of flow deviation from the number of inlets, circumferential position, and flow resistance symmetry.

[0008] In the engineering design of a direct coal liquefaction feed unit, the circumferential angle between the two circulating oil feed pipes is 180°±5°. The two circulating oil feed pipes have the same nominal diameter, the ratio of their lengths extending into the mixing chamber is 0.95 to 1.05, the difference in outlet center height is no greater than 0.05 times the nominal diameter, and the difference in axial inclination angle is no greater than 3°. The axes of the two pipes are inclined upwards at 20° to 45° relative to the horizontal plane so that the circulating oil enters from opposite sides at the bottom of the mixing chamber.

[0009] The lower part of the annular distribution pipe is provided with injection holes facing obliquely downwards towards the mixing chamber. Taking a plane perpendicular to the central axis of the mixing chamber as the horizontal plane, the axis of the injection hole is inclined downwards at 20° to 45° relative to this horizontal plane along the direction in which the reactants are injected into the mixing chamber from the annular distribution pipe. The equivalent orifice diameter is 6 to 20 mm and is not less than 3 times the particle size d95 corresponding to a cumulative mass fraction of 95% in the reactants. The center distance between adjacent injection holes is 2 to 5 times the equivalent orifice diameter of the injection hole.

[0010] The annular distribution pipe section between two adjacent reaction feed pipes is taken as a feeding sector. The diameter of the injection orifice in the same feeding sector increases symmetrically in 2 to 4 levels from the two ends of the circumferential direction to the middle of the circumferential direction. The diameter is the largest in the middle of the circumferential direction. The ratio of the largest diameter to the smallest diameter is 1.10 to 1.30 to compensate for the pressure drop along the annular distribution pipe.

[0011] The downcomer is installed vertically downwards along the central axis of the mixing chamber and the reactor. The portion of the downcomer inside the mixing chamber remains a straight pipe without inclined sections or bends, and the angle between its axis and the central axis of the mixing chamber is no greater than 3°. The outer diameter of the downcomer is 0.10 to 0.25 times the inner diameter of the mixing chamber, and a continuous annular flow space is formed between the outer wall of the downcomer and the inner wall of the mixing chamber.

[0012] The function of the circulating oil feed pipe is to change the original single bottom inlet single-sided oil supply to two opposite inlets balanced oil supply, reducing the circumferential flow deviation at the bottom of the mixing chamber; the function of the downcomer is to change the original obliquely led-out flow path to a central vertical straight flow path, reducing local resistance, low-speed retention and particle blockage at the oblique pipe and bend.

[0013] A distribution plate is positioned above the annular distribution pipe, and the mixture enters the reactor through flow holes on the distribution plate. A blower head can be installed at the top of the annular distribution pipe; when the pressure difference across the distribution plate exceeds a preset cleaning threshold, the abnormal area is purged, and the purging stops once the pressure difference recovers. This blowing structure serves as additional protection for long-term operation, rather than being the sole innovative feature of the three-dimensional mixing flow field of this invention.

[0014] The present invention also provides a direct coal liquefaction reactor, including the above-mentioned feed distribution device and a reactor cylinder located above it.

[0015] The present invention also provides an operating mode: circulating oil is simultaneously introduced through two circulating oil feed pipes and the flow deviation between the two paths is controlled, and then the reactant is introduced into the annular distribution pipe through two reaction feed pipes, so that the reactant enters the mixing chamber through the inclined downward injection hole, and the mixed material bypasses the central straight downcomer and enters the reactor through the distribution plate.

[0016] Compared to traditional structures, the difference in this invention lies not in simply adding a pipe or changing the orifice diameter, but in: replacing the single bottom circulating oil inlet with a dual inlet spaced 180° apart circumferentially, with matching geometric parameters and flow resistance conditions; replacing the inclined or bend-type downcomer with a straight pipe vertically downward along the central axis; and using angle, orifice diameter, and zoned orifice diameter compensation of the inclined downward injection holes as complementary uniform distribution measures. The above structures reduce flow deviation and blockage from both the inlet boundary conditions and the solid transport path aspects. Attached Figure Description

[0017] To more clearly illustrate the structural relationships of the present invention, a brief description of the accompanying drawings is provided below. The drawings are schematic diagrams of the structure; specific angles and dimensions are as defined in the specification and claims.

[0018] Figure 1 This is a schematic diagram of the overall structure of a feeding and dispensing device according to the present invention; Figure 2 This is a schematic diagram of the assembly structure of the annular distribution pipe and the reaction feed pipe; Figure 3 A top view of the feed distribution device; Figure 4 A schematic diagram of a direct coal liquefaction reactor; The components include: 1. Mixing chamber; 2. Annular distribution pipe; 210. Injection hole; 3. Reaction feed pipe; 4. Circulating oil feed pipe; 5. Distribution plate; 510. Flow hole; 6. Reactor shell; 7. Blower head; 8. Downcomer. Detailed Implementation

[0019] The embodiments of the present invention will be described below with reference to the accompanying drawings. The structural parameters are determined based on the particle throughput capacity of the direct coal liquefaction coal slurry containing solids and oil, the allowable pressure drop of the annular distribution pipe, the flow balance of the two circulating oil feed pipes, and the material erosion resistance requirements; the claims use engineering application scope, while the embodiments use specific design values.

[0020] Example 1: Feeding and Distributing Device See Figures 1 to 3 The feed distribution device includes a mixing chamber 1, an annular distribution pipe 2, a reaction feed pipe 3, a circulating oil feed pipe 4, a distribution plate 5, and a downcomer 8. The mixing chamber 1 is located below the reactor shell 6, the annular distribution pipe 2 is located in the upper region of the mixing chamber, and the distribution plate 5 is located above the annular distribution pipe 2.

[0021] Two reaction feed pipes 3 are arranged 180° apart circumferentially in the annular distribution pipe 2. Two circulating oil feed pipes 4 are located below the annular distribution pipe 2 and are arranged 180° apart circumferentially in the mixing chamber 1. The first axial plane, which includes the central axis of the mixing chamber 1 and passes through the central axes of the two reaction feed pipes 3, differs from the second axial plane, which includes the central axis of the mixing chamber 1 and passes through the central axes of the two circulating oil feed pipes 4, by 90°±5°, forming... Figure 3 The arrangement shown is orthogonal and symmetrical.

[0022] In this embodiment, the two circulating oil feed pipes 4 have the same nominal diameter, the same outlet height, the same axial tilt angle, and the same insertion length. The circumferential position deviation of the outlets of the two circulating oil feed pipes 4 is controlled within ±5°, the difference in center height between the outlets of the two circulating oil feed pipes 4 is not greater than 0.05 times the nominal diameter, and the difference in axial tilt angle between the two circulating oil feed pipes 4 is not greater than 3°. Taking the plane perpendicular to the central axis of the mixing chamber 1 as the horizontal plane, the axial tilt angle of the circulating oil feed pipe 4 refers to the angle between the central axis of the circulating oil feed pipe 4 and the horizontal plane.

[0023] The plane perpendicular to the central axis of mixing chamber 1 is taken as the horizontal plane. Along the direction of the circulating oil flow from the outer end of the pipe to the mixing chamber, the axis of the circulating oil inlet pipe 4 is inclined upwards at 30° relative to this horizontal plane. The outlets of the two circulating oil inlet pipes 4 supply oil from opposite sides at the bottom of the mixing chamber towards the central area. The two circulating oil inlet pipes 4 have the same nominal diameter and each carries 50% of the total designed circulating oil flow rate. During operation, the flow rates of the two circulating oil inlet pipes 4 are adjusted to ensure that the flow rate deviation between the two circulating oil paths does not exceed 5%, thereby reducing the circumferential velocity gradient and flow deviation caused by single-inlet oil supply.

[0024] An injection hole 210 is provided at the lower part of the annular distribution pipe 2. In this embodiment, along the direction in which the reactant is injected into the mixing chamber from the annular distribution pipe 2, the axis of the injection hole 210 is inclined downward at 30° relative to the horizontal plane; in accordance with the condition that the equivalent orifice diameter is not less than three times the particle size d95 corresponding to the cumulative mass fraction of coal slurry reaching 95% and combined with the allowable pressure drop of the annular distribution pipe, the injection hole 210 adopts three equivalent orifice diameters of 10 mm, 11 mm and 12 mm, and the center distance between adjacent injection holes is 30 mm.

[0025] The annular distribution pipe 2 is divided into two feeding sectors by two reaction feed pipes 3. Within each feeding sector, the diameter of the injection orifice 210 increases symmetrically in three levels from the two ends of the circumferential direction of the feeding sector toward the center, at 10 mm, 11 mm and 12 mm, with a 12 mm diameter at the center. The ratio of the maximum diameter to the minimum diameter is 1.20 to compensate for pressure drop along the flow path.

[0026] The downcomer 8 is arranged vertically downward along the central axis of the mixing chamber 1 and the reactor shell 6. The portion of the downcomer 8 located inside the mixing chamber 1 remains a continuous straight pipe without any oblique outlet sections or bends. In this embodiment, the angle between the axis of the downcomer 8 and the central axis of the mixing chamber 1 is no greater than 3°, and the outer diameter of the downcomer 8 is 0.18 times the inner diameter of the mixing chamber 1.

[0027] Since the downcomer 8 no longer passes obliquely through the bottom of the mixing chamber, the low-speed stagnation zone inside the oblique pipe and at the bend can be reduced; the downcomer 8, located in the center, also provides symmetrical external flow space for the circulating oil inlets on both sides, so that the dual-inlet balanced oil supply and straight pipe anti-clogging form the same bottom structure system.

[0028] A flow passage 510 is provided on the distribution plate 5, through which the mixture enters the reactor body 6. A blower head 7 is provided on the upper part of the annular distribution pipe 2, and the blower head 7 can be grouped according to the circumferential area of ​​the distribution plate 5. When the differential pressure indication of a certain area shows a tendency to blockage, only the blower head 7 of the corresponding group is turned on; when multiple areas are abnormal, multiple groups of blower heads 7 can be turned on at the same time.

[0029] If the throughput, slurry viscosity, or solid particle size changes, the number and aperture difference of the injection holes 210 can be adjusted, but the structural relationship of the two circulating oil feed pipes 4 being symmetrical about the central axis of the mixing chamber 1, the matching of the geometric parameters of the two pipes, and the coaxial vertical straight connection of the downcomer 8 should be maintained.

[0030] Example 2: Coal Direct Liquefaction Reactor See Figure 4 The direct coal liquefaction reactor includes a reactor shell 6 and the feed distribution device of Example 1. The feed distribution device is located below the reactor shell 6, and the mixed material enters the reaction space of the reactor shell 6 via a distribution plate 5. Other internal components of the direct coal liquefaction reactor can be selected according to the direct coal liquefaction process.

[0031] Example 3: Operating Mode During startup, both circulating oil feed pipes 4 are opened simultaneously, allowing circulating oil to enter from opposite sides at the bottom of the mixing chamber. The flow deviation between the two lines is controlled within 5% by checking the valve opening or the flow rate of the circulating oil feed pipes. After the circulating oil supply stabilizes, the two reaction feed pipes 3 are opened to send the reactants, consisting of oil-coal slurry and hydrogen-containing gas, into the annular distribution pipe 2.

[0032] The reactants enter the mixing chamber through the downward-sloping injection holes 210 and mix with the circulating oil. The resulting mixture bypasses the central vertical downcomer 8 and enters the reactor body 6 through the annular flow space outside the downcomer 8 and the distribution plate 5. The descending material then passes vertically through the lower part of the mixing chamber along the straight section of the downcomer 8.

[0033] During operation, monitor the pressure difference across distribution panel 5. When the pressure difference exceeds 0.10 MPa, activate the blower head 7 corresponding to the abnormal area; when the pressure difference is less than 0.05 MPa, deactivate the activated blower head 7. Use different activation and deactivation thresholds to create hysteresis and prevent the blower head 7 from frequently starting and stopping near the critical pressure difference.

[0034] The engineering design values ​​for this embodiment are as follows: taking the plane perpendicular to the central axis of the mixing chamber 1 as the horizontal plane, along the direction of the circulating oil flowing from the outer end of the pipe to the mixing chamber, the axis of the circulating oil feed pipe 4 is inclined upward at 30° relative to this horizontal plane; along the direction of the reactants being sprayed into the mixing chamber from the annular distribution pipe 2, the axis of the injection hole 210 is inclined downward at 30° relative to this horizontal plane; the equivalent aperture of the injection hole 210 is 10 mm, 11 mm, and 12 mm, the hole center distance is 30 mm, the ratio of the maximum aperture to the minimum aperture is 1.20, the ratio of the outer diameter of the downcomer 8 to the inner diameter of the mixing chamber 1 is 0.18, and the flow rate deviation between the two circulating oil paths does not exceed 5%. When the equipment throughput or the coal slurry particle size changes, the selection is made proportionally according to the range of angles, apertures, hole distances, and diameter ratios defined in the claims.

[0035] In the embodiments of this application, the same reference numerals are used to represent the same component or the same part; without deviating from the central symmetry of the dual circulation oil inlet, the matching of the two flow resistances, and the vertical straight-through relationship of the downcomer, those skilled in the art can make adaptive adjustments to the quantity, size, and connection method.

Claims

1. A feeding and dispensing device, characterized in that, The system includes a mixing chamber, an annular distribution pipe, two reaction feed pipes, two circulating oil feed pipes, a distribution plate, and a downcomer. The annular distribution pipe is located within the mixing chamber of the mixing chamber. The two reaction feed pipes are connected to the annular distribution pipe. The lower part of the annular distribution pipe has injection holes distributed circumferentially and pointing obliquely downward toward the mixing chamber. The two circulating oil feed pipes are located below the annular distribution pipe and are connected to the mixing chamber. The outlet centers of the two circulating oil feed pipes are 180° apart circumferentially in the mixing chamber and symmetrical about the central axis of the mixing chamber. The nominal diameter, outlet center height, pipe axis inclination angle, and length extending into the mixing chamber of the two circulating oil feed pipes are matched to allow circulating oil to be input from opposite sides at the lower part of the mixing chamber. The downcomer is vertically downward along the central axis of the mixing chamber and penetrates the mixing chamber. The portion of the downcomer inside the mixing chamber is a straight pipe without oblique sections or bends.

2. The feeding and dispensing device according to claim 1, characterized in that, The centers of the two reaction feed pipes are 180°±15° apart in the circumferential direction of the mixing chamber, and the circumferential angle between a first axial plane containing the central axis of the mixing chamber and passing through the central axis of each of the two reaction feed pipes and a second axial plane containing the central axis of the mixing chamber and passing through the central axis of each of the two circulating oil feed pipes is 90°±15°.

3. The feeding and dispensing device according to claim 1, characterized in that, The two circulating oil feed pipes have the same nominal diameter, the difference in outlet center height is no greater than 0.05 times the nominal diameter, the difference in pipe axis inclination angle is no greater than 3°, and the ratio of their lengths extending into the mixing chamber is 0.55 to 2.

05.

4. The feeding and dispensing device according to claim 1, characterized in that, With the plane perpendicular to the central axis of the mixing chamber as the horizontal plane, the pipe axes of the two circulating oil feed pipes are inclined upward at 10° to 85° relative to the horizontal plane, and the projections of the outlet axes of the two circulating oil feed pipes on the horizontal plane have a radially inward component pointing towards the central axis of the mixing chamber.

5. The feeding and dispensing device according to claim 1, characterized in that, With the plane perpendicular to the central axis of the mixing chamber as the horizontal plane, the axis of the injection hole is inclined downward at 10° to 85° relative to the horizontal plane along the direction in which the reactant is injected into the mixing chamber from the annular distribution pipe; the equivalent aperture of the injection hole is 3 to 50 mm, and is not less than 3 times the particle size d95 corresponding to the cumulative mass fraction of the reactant reaching 95%; the center distance between adjacent injection holes is 1 to 10 times the equivalent aperture of the injection hole.

6. The feeding and dispensing device according to claim 5, characterized in that, The annular distribution pipe section between two adjacent reaction feed pipes is considered as a feeding sector. The equivalent aperture of the injection hole in the same feeding sector increases symmetrically in 2 to 4 levels from the two ends of the circumferential direction to the middle of the circumferential direction. The ratio of the maximum equivalent aperture to the minimum equivalent aperture is 1.00 to 3.

00.

7. The feeding and dispensing device according to claim 1, characterized in that, The angle between the axis of the downcomer and the central axis of the mixing chamber is no greater than 10°. The outer diameter of the downcomer is 0.10 to 2.5 times the inner diameter of the mixing chamber, and a continuous annular flow space is formed between the outer wall of the downcomer and the inner wall of the mixing chamber.

8. The feeding and dispensing device according to claim 1, characterized in that, The distribution plate is provided with a flow passage hole that runs vertically through it. The upper part of the annular distribution pipe is provided with a blowing head facing the lower surface of the distribution plate and the flow passage hole. The blowing head is connected to the control system signal.

9. A direct coal liquefaction reactor, characterized in that, The device includes a feeding and distributing device as described in any one of claims 1 to 8 and a reactor cylinder located above the feeding and distributing device, wherein the mixture formed in the mixing chamber can enter the reactor cylinder through the distributing plate.

10. An operating mode of a feeding and distributing device, characterized in that, The feeding and distributing device is the feeding and distributing device according to claim 8. The operation mode includes: simultaneously introducing circulating oil from opposite sides of the lower part of the mixing chamber through two circulating oil feed pipes, and controlling the flow rate deviation of the two circulating oil feed pipes to within 10%; introducing a reactant material composed of oil-coal slurry and hydrogen-containing gas into the annular distribution pipe through two reaction feed pipes, so that the reactant material enters the mixing chamber through the downwardly arranged injection hole and mixes with the circulating oil; allowing the mixture to bypass the vertically arranged downcomer and flow upward through the annular flow space outside the downcomer, and then pass through the distribution plate into the reactor body; opening the blowing head when the pressure difference between the upper and lower parts of the distribution plate is greater than 0.10 MPa, and closing the blowing head when the pressure difference between the upper and lower parts of the distribution plate is less than 0.05 MPa.

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