JPH0420654B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluid flow distribution system for uniformly introducing feed and recycle fluid streams into a reactor plenum and boiling catalyst bed. More particularly, the present invention relates to such a flow distribution apparatus for handling petroleum and coal-oil slurry streams and gas streams to create a substantially uniform flow distribution upwardly within the boiling catalyst bed.

Experience in operating pilot plants and commercial ebullated bed catalytic reactors used in the H-Oil and H-Coal ^m processes has shown that the distribution of inlet streams in the reactor plenum is It has been found that improper design of the catalyst can lead to operational difficulties such as coke formation in the plenum, poor flow distribution in the catalyst bed, local settling of the catalyst bed, and coke formation in the catalyst bed. . These problems reduce catalyst utilization, resulting in frequent reactor shutdowns and shortened operating periods.

The prior art clearly does not provide an adequate solution to such flow distribution problems in fluidized bed catalytic reactors. For example, U.S. Pat. No. 3,197,288 discloses a catalytic reactor structure that uses simple conduits to introduce inlet feed liquid and recycle liquid into the plenum chamber of the reactor, and U.S. Pat. Discloses the use of a dual spargeer at the lower end. Additionally, U.S. Patent No.
No. 3,540,995 discloses the operation of a coal hydrogenation process using a boiling catalyst bed reactor to introduce feed and recycle liquid streams into a plenum at the lower end of the reactor below a flow distribution grid means. However, the introduction of such gas and liquid streams into the reactor plenum at high speeds requires relatively specialized arrangements to achieve proper mixing and uniform flow distribution of these streams.

It is an object of the present invention to provide an improved flow distribution system in which a desirable uniform flow pattern occurs within the reactor plenum and upwardly through distribution grid means into the catalyst bed.

The present invention provides a flow distribution device for uniformly distributing a flow of fluid material into an ebullated bed of a reactor.
(a) a plenum located in the lower part of the reactor and formed by the lower end wall and lower side wall of the reactor and a distribution grid located below the ebullated bed in the reactor; (b) a conduit projecting into said plenum for delivering a flowable fluid substance into said plenum; (c) a baffle nozzle rigidly attached to an inner end of said conduit; at least two nozzles spaced apart from each other
a plurality of baffles oriented upwardly, the innermost baffle plate comprising a plate having no aperture, and at least one other baffle plate having a central aperture and said baffle plate having no aperture; disposed upstream of the plate so that gas and liquid substances supplied into the plenum through the conduit are mixed by the baffle nozzle, and connecting the baffle nozzle with the distribution grid. characterized in that they are arranged in combination so that the flow of said liquid and gas mixture is substantially uniformly distributed within said ebullated bed.

The present invention is particularly useful for handling hydrocarbon feed streams, such as petroleum and coal slurries, with hydrogen gas for uniform distribution within a boiling catalyst bed reactor. Accordingly, the term "gas and liquid mixture" is intended to include a mixture of gas and liquid slurry containing fine solid particles.

In the present invention, the flow of a fluid, such as a mixture of a liquid slurry obtained from coal and hydrogen gas, is arranged at the lower end of the reactor through a conduit and a nozzle distributor with disk-doughnut baffles. Enter the plenum. Typically, this distributor comprises a series of generally parallel spaced baffles placed at an angle of 45 to 90 degrees to the centerline of the inner end of the conduit and extending laterally or radially outward into the plenum. Divert the flow in a direction. Further, the center axis of the nozzle distributor with baffle plate is arranged so as to form an angle of 0 to 60 degrees with the center lines of the plenum and the reactor. Inlet flow distributor with baffle plate for the reactor plenum of a gas-liquid-solid particle fluidized bed reactor provides a non-fouling distributor for dispersing the kinetic energy of a flowing fluid fed into the plenum chamber. . This distributor prevents the recirculating liquid and gas streams from "jetting" into the plenum and distributes the liquid flow evenly within the plenum.

Depending on the operating conditions of the reactor and the available space within the plenum, the flow distributor can be of various configurations. The liquid flow distributor includes at least two liquid flow distributors disposed at the outlet of the recirculating liquid conduit entering the plenum.
It can be constructed from a number of preferably circular baffles. When a vertical nozzle with a central opening is placed in a plenum, the baffles are typically spaced equidistant from each other. The innermost plate of the distributor, the top plate, has no openings and deflects the incoming flow laterally to prevent liquid from impinging directly on the bottom surface of the grid plate.
The other baffle or distribution plate of the distributor has a central opening sized to intercept and deflect a portion of the liquid flow laterally, ie, radially outwardly into the plenum. These lateral flow channels sweep the bottom of the plenum to eliminate stagnation areas and provide good mixing of gas and liquid (or gas and liquid slurry) and pass upwardly through the openings of the flow distribution grid. and is directed to create a substantially uniform flow into the boiling catalyst bed.

Although the proportion of total material flowing radially outward from the gap between each adjacent baffle plate can be varied by selecting the dimensions of the distributor, it is common for a relatively large proportion of the total flow to exit through the lowest gap. be done. A typical baffle plate device design has 40-45% of the incoming liquid flow deflected by the first plate, 25-35% by the intermediate plate, and the remainder of the flow deflected radially outward by the top plate. deflect. For nozzle configurations that enter the plenum from one side, the deflectors are typically oriented at an angle of about 0° to about 10° with the adjacent baffle to direct the recirculating gas/liquid flow within the plenum. Distribute evenly.

For small diameter reactors with an internal diameter of less than about 5 feet, the feed liquid and gas streams are typically mixed with reactor recycle liquid external to the reactor;
This combined mixture is then added to the first
It is more convenient to distribute uniformly within the plenum of the reactor using the distribution device shown. Approximately 182.9cm
For reactors having diameters larger than (6 feet), it is usually desirable to introduce the feed liquid and gas mixture into the reactor plenum from a separate distributor. For example, a normally circular perforated sparge ring can be placed above the plenum and used to uniformly distribute the gas-liquid feed mixture across the plenum of the reactor. Uniform flow of bubbles and liquid feed material is produced by providing a pressure drop through the sparger and directing the mixed gas-liquid flow from the sparger downward to substantially dissipate the kinetic energy of the flow in the liquid. This kinetic energy is used to increase the intensity of backmixing of the liquid within the plenum. The pressure drop through the opening of the sparge ring is typically ¹ to 15 psi for typical heavy crude oil reforming and coal liquefaction processes.

In another embodiment of the invention, the downcomer for the recirculating liquid of the reactor can be routed through the center of a baffle distributor, which preferably consists of three baffles. Recirculated reactor liquid enters the reactor plenum through an annular area between the liquid downconduit and the inlet nozzle. The central openings in the first and intermediate baffles allow the liquid flow to disperse laterally and uniformly radially outwardly across the reactor plenum and to sweep the bottom of the plenum and stagnate. Size it so that there is no area left. A top baffle plate without openings prevents liquid from impinging directly on the distribution grid.

An inlet flow baffle nozzle distributor is combined upstream with a reactor distribution grid to provide an excellent flow distribution system for a boiling catalyst bed reactor.
The pressure drop through a baffled nozzle distributor at rated flow rate is typically about 5 to 25% of the total pressure drop through both the distributor and distribution grid. Although the distribution grid may consist of a perforated plate, it is preferred that the distribution grid comprises a number of tubes, each tube provided with a cap on its upper end. This distribution device provides excellent gas-liquid contact and gas mixing within the reactor plenum, eliminates direct impingement of the liquid stream with the distribution grid, and prevents coke formation in the plenum and catalyst bed. Minimize.

The invention will now be explained by way of example with reference to the drawings.

As shown in FIG.
into the plenum chamber 12 of. This plenum chamber 12 can be lined with refractory insulation 15. The inlet tube 10 has a baffle nozzle or disk-doughnut flow distributor 16 that is generally upwardly directed and supplies a mixture of liquid and gas into the plenum and then to a flow distribution grid 18. is uniformly fed upwardly into the boiling catalyst bed 20 through the openings 19 of the catalyst. Reactor liquid is withdrawn from above the catalyst bed and descends through central conduit 24 to a recirculation pump (not shown). Liquid from this pump is recycled through inlet tube 10 to flow distributor 16 along with fresh liquid and gas feed. Plenum 12 preferably has a height equal to 5 to 10 times the inside diameter of inlet tube 10 and distribution grid 18 preferably has a diameter equal to 4 to 12 times the inside diameter of inlet tube 10. The flow distributor 16 preferably projects into the plenum a distance equal to about 2.5 to 9 times the inside diameter of the inlet tube 10 from below the distribution grid plate 18 and extends beyond the bottom of the plenum. Preferably, it protrudes a distance equal to 1.0 to 2.5 times the inner diameter of.

As shown in detail in FIG. 2, the flow distributor 16 comprises at least one annular plate 30 having a central aperture 31 upstream of a disc 32 which does not have an aperture. It is set in. All of these are held together by three rods 33 that are equally spaced apart in the circumferential direction. Bar 33
Preferably, it is located at the outer edge of the baffle plate.
It typically has a central opening 35 that becomes progressively smaller.
One additional annular plate 34 is placed intermediate plates 30 and 32 to provide a suitable distributor structure for further radially distributing the flow from the inlet tube 10. Preferably, a greater proportion of the flow is emitted through the lowest gap. This is because the fluid has a longer distance to travel within plenum 12 to reach distribution grid 18. In the case of the preferred flow distributor with three plates, the dimensions of the plates are:
About 40-45 volume percent of the fluid flow is deflected radially outwardly by the first or upstream baffle 30 and about 25-35 volume percent is deflected outwardly by the second or intermediate baffle 34. , is preferably selected such that the remainder of the flow is deflected radially by the top or downstream baffle 32, which has no openings.

The three baffle plates spaced apart from each other are arranged to form an angle of 40 to 90 degrees with the centerline of the inner end of the inlet tube 10. Further, the axis of the nozzle with a baffle plate is arranged so as to form an angle α of 0 to 60° with the center line of the plenum 12 and the reactor 14. Additionally, if desired, each baffle plate can be oriented at an angle of 0 to 10 degrees with the adjacent baffle plate to uniformly distribute the gas and liquid mixture within the plenum 12.

FIG. 3 shows another example of the fluid flow distribution device of the present invention. In this example, the flow distributor 16 is centrally located at the bottom of the plenum chamber 12 below the distribution grid 18 and above the bottom of the plenum.
Protrude a distance equal to 1.0-2.5 times. Flow distribution grid 18 includes a number of standpipes 26, each with an internal diameter of 19.05 to 38.1 mm (0.75 to 1.5 inches), each extending from the grid a distance equal to 4 to 10 times the internal diameter of the tube. Preferably, it extends below 18. The tube 26 projects above the grid 18 by a distance equal to 1.5 to 4 times the inner diameter of the tube. A cylindrical cap 28 is provided above the upper end of each tube 26, spaced from the tube 26, and rigidly supported therefrom by suitable structural members (not shown). Cap 28 allows catalyst solid particles 22 to flow from boiling bed 20 into tubes 26 whenever there is no upward fluid flow through the tubes, such as may occur during turbulent operating conditions or at process stoppages. It is oriented in such a way as to prevent it from entering. A circular sparge ring 40 is provided above the flow distributor 16 with uniformly spaced apertures 41 in the underside of the sparge ring 40 so that the upper part 12 of the plenum chamber
Evenly distribute the gas and liquid flows at a. A sparger 40 surrounds the downcomer 24 and is particularly useful in large diameter reactors, such as reactors having an internal diameter greater than about 8 feet. The openings 41 are all sized to provide a uniform pressure drop and positioned so that the flow is downward, dissipating most of its kinetic energy, and increasing back-mixing of gas and liquid in the plenum.

In yet another example of the invention shown in FIG. 4, downcomer pipe 44 passes through the center of baffle flow distributor 46. Distributor 46 consists of three annular plates supported from conduit 44 and upward fluid flow is supplied to distributor 46 by annular conduit 45 . A top plate 47, which does not have an opening, is firmly attached to the conduit 44, for example by welding, and is positioned substantially perpendicular to the conduit 44. The intermediate plate 48 has an annular opening 49, and the plate 48 is connected by means of three rods 53 equidistantly spaced apart from the plate 48.
Install it on 7. The lower plate 50 has the opening 4 in the intermediate plate 48.
It has an annular opening 51 slightly larger than 9. Flow distributor 46 thus operates in the same manner as distributor 16, such that a portion of the total upward fluid flow passes radially outwardly through the adjacent plate-to-plate tube gaps. In this case as well, a circular sparger 60 having a plurality of openings spaced apart from each other is inserted into the plenum chamber.
2 and centered above the flow distributor 46, similar to the sparger 40 in the example shown in FIG. The sparger 60 has an opening 61.

The effects achieved by using the inlet flow distributor and distribution device structure of the present invention are illustrated with respect to the following examples.

EXAMPLE Using the Etchcoal ^m process for liquefying coal, a 152 cm (5 ft) internal diameter ebullated bed catalytic reactor (200 tons/day Etchcoal m process) was used.
In a coal hydrogenation plant equipped with a pilot reactor, the feed coal slurry and hydrogen gas were mixed with the recycled liquid stream from the ebullated bed outside the reactor. The entire combined stream was then distributed through a side entry nozzle fitted with three angled baffles as described with respect to FIG. As a result of installing the distribution nozzle in the reactor plenum, coking due to poor flow distribution in the boiling catalyst bed of the reactor has been virtually eliminated.

In a reactor design for a commercial Etchcoal (18,000 ton/day) plant with an internal diameter of 335 cm (11 ft), the feed A circular sparger for distributing liquid slurry and gas was installed in the plenum. Vertical nozzle fitted with three horizontal plates for dispersing the recycled liquid stream from the ebullated bed in a reactor design for a 305 cm (10 ft) internal diameter commercial ETS (5562 kl (35000 bbl)/day) plant. and a sparge ring for distributing the liquid and gas feed streams constituted the inlet flow distribution system in the plenum of the reactor.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of an example of the lower part of an ebullated bed reactor equipped with the device of the present invention, FIG. 2 is a vertical cross-sectional view of an example of a flow distributor which is a nozzle with a baffle plate in the device of the present invention, and FIG. 4 is a vertical cross-sectional view of another example of the apparatus of the invention for introducing feed and recycle streams into the reactor plenum from separate flow devices; FIG. 4 is a still further example of the apparatus of the invention similar to FIG. FIG. 10... Conduit (inlet pipe), 12... Plenum (plenum room), 12a... Upper part of plenum room, 1
4... Reactor, 15... Fireproof insulator, 16... Nozzle with baffle plate (distributor), 18... Distribution grid (distribution grid plate), 19... Opening, 20...
... Boiling catalyst bed, 22 ... Catalyst solid particles, 24 ...
Central conduit (downcomer pipe), 26... Vertical pipe, 28...
Cap, 30...first deflecting plate (upstream deflecting plate, annular plate), 31... central opening, 32... deflecting plate without opening (disc without opening, top deflecting plate, downstream deflecting plate), 33...rod,
34...Second deflecting plate (intermediate deflecting plate, annular plate),
35... central opening, 40... sparge ring, 41... opening, 44... conduit (downcomer pipe), 45... annular conduit, 46... distributor,
47... Upper plate without opening, 48... Intermediate plate, 49... Opening, 50... Lower plate, 51...
Opening, 53...rod, 60...spargeer, 61
...Opening.

Claims (1)

Claims: 1. A flow distribution device for uniformly distributing a flow of fluid material into an ebullated bed of a reactor, comprising: (a) a lower end wall of the reactor; a plenum formed by a lower sidewall and a distribution grid disposed below an ebullated bed in said reactor; (b) projecting into said plenum for delivering flowable fluid material into said plenum; (c) a baffle nozzle rigidly attached to an inner end of the conduit, the baffle nozzle having at least two spaced apart baffles and upwardly oriented;
the innermost baffle plate comprises a plate without an aperture, and at least one other baffle plate has a central aperture and is disposed upstream of said non-aperture baffle plate, said conduit gas and liquid materials supplied into the plenum through the baffle nozzle are mixed by the baffle nozzle, and the baffle nozzle is arranged in combination with the distribution grid to mix the liquid and gas. A flow distribution device characterized in that the flow of the mixture is substantially uniformly distributed within the ebullated bed. 2. The apparatus of claim 1, wherein the spaced apart baffles are oriented at an angle of 45 DEG to 90 DEG with the axis of the inner end of the conduit. 3. The apparatus according to claim 1, wherein the axis of the baffle plate nozzle is arranged to form an angle of 0 to 60 degrees with the center line of the plenum and the reactor. 4. The nozzle consists of three circular deflectors,
The lower first plate has a central opening, the intermediate second plate has a central opening smaller than the central opening of the lower first plate, and the upper third plate has no opening. The device according to scope 1. 5 the central opening of the lower first plate has a diameter of 0.6 to 0.75 times the inner diameter of the conduit;
2. The device of claim 1, wherein the central opening in the plate has a diameter between 0.4 and 0.5 times the inner diameter of the conduit. 6. The apparatus of claim 1, wherein the baffles are spaced apart a distance equal to 0.3 to 0.5 times the inner diameter of the conduit. 7. The apparatus of claim 1, wherein an annular sparger is provided in the plenum below the distribution grid and above the baffle nozzle. 8. The apparatus of claim 1, wherein the baffle nozzle projects above the bottom of the reactor plenum a distance equal to 1.0 to 2.5 times the inner diameter of the conduit. 9. The apparatus of claim 1, wherein the plenum has a height equal to 5 to 10 times the inner diameter of the conduit. 10 The distribution grid is approximately 4 to 4 mm in diameter of the conduit
Device according to claim 1, having a diameter equal to 12 times. 11 the downcomer is centrally located within the plenum and extends longitudinally through the distribution grid and the plenum, and the baffle nozzle is located externally and concentrically with the downcomer; An apparatus according to claim 1.