FR2532859A1 - DEVICE AND FLUID DISTRIBUTION ASSEMBLY FOR A BILK BED REACTOR - Google Patents

Abstract

THE INVENTION CONCERNS FLUID CURRENT DISTRIBUTION DEVICES. IT RELATES TO A DEVICE INCLUDING A NOZZLE 16 MOUNTED AT THE END OF A SUPPLY DUCT 10. THIS NOZZLE INCLUDES THREE DEFLECTOR PLATES, THE END PLATE BEING SOLID AND THE OTHER TWO HAVING DIFFERENT DIMENSIONS. IN THIS WAY, THE CURRENT TRANSMITTED THROUGH DUCT 10 IS LATERAL DEVIED AND SWEEP THE BOTTOM OF THE REACTOR PREVENTING THE FORMATION OF STAGNATION ZONES. APPLICATION TO REACTORS FOR TREATMENT OF HYDROCARBON MATERIALS IN FLUIDIZED BEDS.

Description

The present invention relates to a device

  and a fluid current distribution assembly,

  to uniformly introduce feed fluid streams and recycled into a pressure chamber and into a bubbling catalyst bed of a reactor It relates in particular to a fluid flow distribution assembly, for the treatment of current oil, suspen sions of oil and gas, traffic initially flowing downwards

  so that the current distribution is substantially uni

  form in a bubbling bed of catalyst -

  Experience with plant reactors

  The pilot and industrial aspects of the "H-Oil" and "H-Coal" processes have shown that improper realization of the distribution of the current introduced into the pressure chamber of the reactor can cause operating difficulties such as the formation of coke in the chamber. under pressure, a poor distribution of the current in the catalyst bed, a localized collapse of the

  catalyst bed, and the formation of coke in the bed.

  These problems have reduced the use of catalysts

  and the need for frequent shutdowns of reactors and

  curved their period of operation.

  There does not seem to be a suitable solution

  nable to this problem of fluid flow distribution

  in fluidized bed catalytic reactors, for example

  United States Patent No. 3,197,288 discloses

  discloses a catalytic reactor configuration having simple conduits for introduction of feedstock and recycled liquid into the reactor pressure chamber, and US Patent No. 3,202,603 discloses the use of dual devices placed bubbler

  at the lower end of a reactor.

  US Pat. No. 3,540,995 generally discloses carrying out a process for hydrogenating coal using a catalyst bed reactor in which the charging liquid streams and recycled are introduced into the pressure chamber formed at the lower end of the reactor, below

  of a current distribution grid However, the

  The production of such streams of gas and liquid in a chamber under the pressure of a high-speed reactor requires more specific arrangements for proper mixing of the currents and uniformity of current distribution.

  advanced developments have been developed

  Positive distribution intended to give reasonably uniform flow diagrams in the chamber

under pressure of the reactor.

  The invention relates to a device and a set

  of fluid flow distribution for the introduction of

  of a liquid or hydrocarbon suspension and a gas in a uniform manner in a pressure chamber

  and in a bubbling catalyst bed of a reactor.

  The invention thus relates to a device for distributing

  uniformly fire a gas-liquid mixture in a hot bed

  a reactor, the distribution device being placed in a pressure chamber of a reactor, this chamber being delimited by a distribution grid and by the lower end and the lower walls of the reactor.

  reactor, below the grid, the device for

  current partition comprising a conduit penetrating the pressure chamber from outside the reactor, the inner end of the conduit being directed downwards

  in the pressure chamber, and a nozzle with deflec-

  placed at the inner end of the duct in the chamber.

  pressure to the lower walls of the reactor so that a hydrocarbon fluid derived at least partially from a reaction in the bubbling bed is recycled, the baffle nozzle having

  at least two substantially parallel deflectors 1

  of the other and fixed rigidly to the inner end of the duct, the innermost baffle being a solid plate, at least one other baffle having a central orifice and being placed upstream of the deflector

  in the form of a solid plate, so that the nozzle with

  bladders mix a gas and a transmitted liquid

  through the duct in the pressure chamber and is

  in combination with the distribution grid, to ensure a substantially uniform distribution of the mixture

  of gas and liquid returned upwards in the boiling bed.

  lonnant. The invention also relates to an assembly intended to ensure a uniform distribution of a fluid material

  in a bubbling catalyst bed of a reactor, the n-

  it seems to comprise a pressure chamber formed at the bottom of the reactor and defined by the lower end and the side walls and by a distribution grid placed under the bubbling bed in the reactor, a conduit opening into the pressure chamber and for transmitting a fluid material

  first downwards in the pressure chamber, and a

  positive distribution located at the lower end of the chamber and associated with the conduit so that it communicates with it, the distribution device mixing a gas and a liquid material transmitted through the conduit in the pressure chamber and being disposed of so that, in combination with the distribution grid, it ensures a substantially uniform distribution of the gas-liquid mixture returned upwards in the bubbling bed

of the reactor.

  In another embodiment of the invention,

  the distribution assembly comprises a pressure chamber formed at the lower part of the reactor and

  delimited by the lower end and the side walls

  of the reactor as well as a distribution grid

  under the bubbling bed in the reactor, a

  the baffle opens into the pressurized chamber and is intended to transfer a fluid material firstly downwards into the pressure chamber W and a conical baffle device placed at the lower end of the pressure chamber, this deflector having its base fixed. rigidly at the lower end of the pressure chamber and having its apex facing the inner end of a

  led, the central axis of the conical deflector being substantially

  in line with the central axis of the inner end of the duct, so that the conical baffle mixes a gas and a liquid material transmitted through the duct into the pressure chamber and is arranged so that, in combination with the distribution grid it ensures a substantially uniform distribution of the gas-liquid mixture

  transmitted upward in the bubbling bed of the reactor.

  The invention is particularly useful for the treatment of hydrocarbon streams such as oil and coal suspensions which must be uniformly distributed with hydrogen gas in a reactor

  bubbling catalyst bed, especially when the

  superficial velocity in the feed duct exceeds about 2.4 m / s Thus, the term "gas-liquid mixture" also refers to a mixture of a gas and a suspension

  in a liquid containing fine particles of a

solid.

  Other features and advantages of the

  will be better understood when reading the description of

  FIG. 1 is a vertical section of the bottom portion of a bubbling bed reactor embodying the invention. FIG. 2 is a vertical cross-section of the invention, with reference to the accompanying drawings in which: FIG. a detail of a baffle nozzle current distribution device used according to the invention; FIG. 3 is a vertical section of a variant of the invention in which the feed streams

  and recycled are introduced by means of circula-

separated; and

  FIG. 4 represents another embodiment of

  invention, similar to that of FIG.

  According to the invention, the feed stream, for example a mixture of a suspension in a liquid from coal and hydrogen at a temperature of 340 to 5100 C and at a pressure of 35 to 210 bar, circulates in a conduit and a splitter device such as a ring-shaped baffle nozzle, opening

  in a pressure chamber placed at the lower end

  The inner end of the duct is directed downwards and the distribution device of the pressure chamber is placed at the inner end of the duct in this chamber and is also directed downwards towards the lower wall of the duct. reactor The splitter device usually contains a series of distant and substantially parallel deflector plates,

  an angle of 45 to 900 with the central axis of the end

  of the duct, the device ensuring the lateral deviation

  radially outward of the current in the pressure chamber The distribution device in the chamber

  under pressure of the fluidized bed reactor of the gas-liquid-type

  solid is a distribution device without fouling ensuring the dispersion of the kinetic energy of the currents

  of fluid transmitted into the chamber.

  prevents jets from being thrown from the recycled liquid and gas stream into the pressure chamber and disperses

  uniformly the liquid flow in this chamber.

  Depending on the operating conditions of the reaction

  tor and the space available in the pressure chamber, the

  splitter device can have various configurations.

  The distributor device of a liquid stream can

  wear at least two deflector plates, preferably

  7 placed at the outlet of the liquid pipe re-

  cycled In the case of a central vertical location of

  the nozzle in the pressure chamber, these deflector plates

  The bottom plate of the distribution device is full and laterally deflects the received stream so that the liquid can not come directly to the bottom of the chamber under pressure. The other deflector or dispersion plates of the device have central orifices

  whose dimensions allow interception and deviation

  portions of the liquid stream in a lateral or radial direction outwardly into the pressure chamber. The flow paths of these side streams are directed so that they sweep the bottom of the chamber under pressure and eliminate the areas of stagnation while ensuring a good mixture of gas and liquid (or gas

  and suspension in a liquid), and a sensible flow.

  sibly uniformly upwards through the orifices formed in a current distribution grid towards the bubbling bed. The percentage of total material flowing radially outwards by the space between

  each pair of deflector plates may vary by

  tion of the dimensions of the distributing device, but usually

  In addition, a larger percentage of the current is emitted

  the lowest space In an example of a deflec-

  approximately 40 to 45% of the introduced liquid stream is deflected by the first plate, 25 to 35% is deflected by the middle plate, and the rest is radially deflected

  outside by the lower plate which is the most in the

  In the case of a nozzle configuration penetrating the chamber under pressure on one side and not placed along the central axis of the chamber, the deflector plates are at an angle varying between 0 and 10 e about with the adjacent deflector plate so that the gas and liquid flow is evenly dispersed in the

pressure chamber.

  In the case of small diameter reactors,

  that is, the internal diameter of which is less than 1.5 m

  the mixing of gas and liquid streams of

  with the recycled liquid from the reactor to the ex-

  The interior of this reactor, before the uniform distribution of the combined mixture in the reactor pressure chamber by means of the distributor of FIG. 1, as described below, is usually very convenient. In the case of reactors whose diameter is greater than about 1.8 m, it is usually desirable for the mixture of gas and feed liquid to be introduced into the pressure chamber of the reactor by means of distribution devices

  For example, a circular ring perforated with barbs

  The stage is usually placed in the upper part of the pressure chamber and can be used for the uniform distribution of the gas and liquid feed mixture in the reactor pressure chamber.

  uniform flow of small bubbles and liquid-al-

  tation is obtained by means of a pressure drop in the

  bubbling water, the mixed streams of gas and

  from the bubbler being downward so that the kinetic energy of the currents is

  practically dissipated in the liquid This kinetic energy

  tick is used to increase the mixing intensity of the liquid by return to the pressure chamber.

  pressure drops at the ports of the bar-ring

  botagç are usually between 0.07 and 1 bar in the case of examples of coal liquefaction processes

  * and to improve the quality of heavy oil crudes.

  In a variant of the invention, the distribution device is formed of a conical deflector whose base is fixed rigidly to the lower wall of the chamber

  under pressure and whose top is directed towards the central axis

  tral of the inner end of the duct and is practically

aligned on this axis.

  This input current distributing device is used upstream and in combination with the reactor distribution grid to form an improved distribution set of a fluid stream for a bubbling catalyst bed reactor.

  charging device at the level of the e-bus distributor

  For the nominal flow rate, the flow rate is usually 25% of the total pressure drop in the distribution device and the distribution grid together. Although the distribution grid may be a perforated plate, it preferably comprises a number of vertical tubes having each a cap at its upper end This

  distribution set ensures excellent gas contact

  liquid and very good mixing of the gas in the pressure chamber of the reactor, eliminates the undesirable direct impact of the fluid streams against the distribution grid, and minimizes the formation of coke in the chamber

  under pressure and in the catalyst bed.

  The invention will now be described in greater detail with reference to FIG. 1 which shows an inlet conduit penetrating into a chamber 12 under pressure of a

  reactor 14 The conduit has a dispatcher device 16

  and that ring or nozzle deflectors, generally oriented downward in the pressure chamber so that it transmits a mixture of liquid and gas in this chamber, the mixture then rising uniformly through the orifices 19 of the grid The reactor liquid is removed above the catalyst bed and sent down through a central conduit 24 to a pump.

  recycling <not shown) from which the

  quide is recycled with a new charge of liquid and

  of gas through the inlet duct 10 to the distributor 16.

  The chamber 12 under pressure preferably has a height equal to 5 to 10 times the internal diameter of the conduit 10, and the distribution grid 18 preferably has a diameter of between 4 and 12 times the internal diameter of the conduit 10. As shown more in detail on the figure

  2, the distributor device 16 comprises at least one

  annular form 30 having a central orifice 31 placed upstream of the lower circular plate pe-ne 32, all elements being retained by three support rods 33 regularly spaced around the circumference and which are of

  placed on the outer edges of the deflector plates

  By way of example, an annular additional plate 34, having a smaller and smaller central orifice 35, can be arranged between the plates 30 and 32 so that it forms an advantageous deflector nozzle configuration, ensuring a better radial distribution. The largest percentage of the current should preferably come from the lowest space, given the greater distance of travel in the pressurized chamber 12 prior to arrival at the distribution grid 18. In the case of a distributor device 16 having three plates, the dimensions of the plates are preferably chosen so that approximately 40 to 45% by volume of the fluid stream is deflected radially outwards by the lower baffle 32, 25 to 35. About one percent by volume is deflected outwardly by the second deflector 34, and the remainder of the stream is radially deflected by the top plate 30, if applicable. , at least one fin 36 of current rectification can be oriented

  in the center inside the duct 10 in the longitudinal direction

  dinal so that the flow diagram, at the level

  of the distributor device 16, is practically unidirectional

  Such a current-straightening fin is

  particularly useful when the deflection angle of the cou-

  fluid flow in the conduit 10 exceeds 30 O.

  FIG. 3 represents a variant of configuration

  tion of the fluid flow distribution assembly se-

  according to the invention, in which the distributor device 16 is placed in the center and is oriented downwards in the lower part of the chamber 12 under pressure, under the distribution grid 18, and is placed above the bottom of the pressure chamber from the reactor at a distance of

  1.0 to 2.0 times the inner diameter of the inlet duct.

  The distribution grid 18 of the current comprises preffered.

  a plurality of vertical tubes 26 before an internal diameter of between 19 and 38 mm, protruding under the grid over a distance equal to 4 to 10 times the internal diameter of the tubes. The tubes 26 protrude from the grid over a distance of approximately 1.5 at 4 times the internal diameter of the tubes A cap 28 of cylindrical shape is placed above the upper end of each tube 26, at a distance from the

  tube, and is rigidly supported by the tube through

  medium of suitable support organs (not shown).

  The cap 28 is oriented to prevent penetration of the solid catalyst particles 22 from the bubbling bed into the tubes 26, when no fluid flow is up in the tube, which can occur during the disturbances. of operation or that exists

when shutting down operations.

  A circular bubbler ring 40 having uniformly spaced orifices 41 at its lower face is placed above the distributor device 16 so that it uniformly distributes a stream of gas and liquid.

  in the upper part 12a of the pressure chamber.

  The sparger device 40 surrounds a channel 24 forming a weir and is particularly useful in the case of large diameter reactors, for example those whose internal diameter exceeds 2.4 m The orifices 41 have dimensions such that they create a loss of uniform charge and they are arranged so that they direct the current downwards, so that its kinetic energy is practically dissipated and the mixture by return of gas and liquid in

  the chamber 12 under pressure is increased.

  In another embodiment of the invention as shown in FIG. 4, the distribution device is formed of a conical deflector 46 placed centrally in the lower part of the chamber 12 under pressure, and its base is fixed rigidly. at the lower wall 49 of the pressure chamber The top 48 of the deflector 46

  is aligned at the end of the end 11 of the conduit 10 of

  this extremity being oriented downwards, so

  that the current from the conduit 10 is diverted from a machine

  substantially radially outwardly, against the lower walls 49 of the pressure chamber 12 The conical surface of the deflector 46 can be rendered

  rectilinear or curved outward at its lower end

1 l 1

  the gradual deviation of the current from the

  gas-liquid mixture to the outside in the pressure chamber is facilitated. Thus, the distributor device

  46 has an operation similar to that of the device

  16, so that all the current flows radially outwards and against the walls of the pressure chamber. A circular bubbler device 40 is placed in the chamber 12 under pressure at its center, above the pressure chamber. splitter device 46, as in the case

of Figure 3.

  The efficiency of using a device

  input splitter having such a configuration is

  dieted by the following examples which are considered

  purely illustrative and not limiting.

EXAMPLES

  In a coal hydrogenation plant using the "H-Coal" process for liquefaction

  coal and having a bubbling bed reactor of

  lyser with an internal diameter of 1.5 m (reactor of

  pilot plant "H-Coal-" Catlettsburg, 180 tonnes / day),

  the gas and the suspension of the feed coal are

  in the stream of bubbling liquid recycled to the outside.

  The total combined weight is then adjusted

  left by a penetrating nozzle laterally and having three

  inclined deflector plates as generally described

  with reference to the embodiment of FIG.

  After fitting the distribution nozzle in the chamber

  under pressure, coking in the boiling bed of cata-

  reactor, due to poor distribution of the

rant, is virtually eliminated.

  In an industrial reactor implementing

  the "H-Coal" process (16 200 tonnes / day), with a di-

  internal meter of 3.3 m, the pressure chamber contains

  a nozzle penetrating laterally and having three plates

  sloping flectrices for dispersing the recycled liquid suspension stream, and a circular barbobage ring for distributing the gas and suspension into

  a feed liquid In an industrial reactor

  both the "H-Oil" process (5 500 m 3 / day), having an internal diameter of 3 m, the distribution set of the inlet stream in the reactor pressure chamber.

  consists of a vertical nozzle with three horizontal plates

  tales for dispersing the ebb and flow of recycled liquid, and a splash ring for distributing

  the gas and the liquid of the supply stream.

  Of course, various modifications may be made by those skilled in the art to the devices which have just been described as non-limiting examples only.

  without departing from the scope of the invention.

Claims (14)

  1 Distribution device intended to ensure a   uniform partition of a mixture of gas and liquid in a bubbling bed of a reactor, the distribution device being placed in a reactor pressure chamber, this chamber being delimited by a distribution grid (18) and by the lower end and the lower walls of the reactor, below the gate, said   distributing device being characterized in that   takes: (a) a conduit (10) entering the underpressure chamber (12) from outside the reactor, the inner end of the conduit being directed downward into the pressure chamber, and   (b) a deflector nozzle (16) placed at the end   internal circuit of the conduit (10) in the pressure chamber (12) and directed downwards to the lower walls of the reactor so that a hydrocarbon fluid drawn at least partially from a reaction in the bubbling bed is   recycled, the deflector nozzle (16) having at least two   substantially parallel fliers (30, 32, 34) spaced from one another and rigidly attached to the inner end of the duct, the inner baffle (32) being formed of a solid plate and another baffle at least (30, 34) having a central orifice and being located upstream of the deflector formed of a solid plate, so that the baffle nozzle (16) mixes a gas and a liquid material transmitted through the conduit into the pressure chamber, and, in combination   with the distribution grid, ensures a   uniformly the gas-liquid mixture rising in the bubbling bed.   2 Device according to claim 1, characterized in that the duct (10) has at least one fin (36) of   current recovery, placed upstream of the nozzle.   3 Device according to claim 1, characterized in that the spaced deflectors (30, 32, 34) are at an angle of 45 to 90 with the central axis of the inner end of the conduit (10) 4 Device according to claim 1, characterized in that the deflector nozzle (16) is centrally located on the longitudinal central axis of the pressure chamber (12), the central axis of the conduit entering the chamber forming an angle of 45 to 90 with the vertical central axis   the pressure chamber (12) and the reactor.   Device according to Claim 17, characterized in that it comprises three circular deflector plates (30, 32, 34), the first upper plate (30) having a central orifice, the second intermediate plate (34) having   a central hole smaller than that of the first   than superior, and the third plate (32) placed the most bottom being full.   6 Device according to claim 5, characterized in that the first upper plate (30) has a central orifice whose diameter is between 0.6 and 0.75 times   the internal diameter of the duct (10), and the intermediate plate   diaire (34) has a central orifice whose diameter is   taken between 0.4 and 075 times the internal diameter of the duct (10).   Device according to claim 1, characterized   in that the deflector plates (30, 32, 34) are separated   by a distance of between 0.3 and 0.5 times the internal diameter of the duct (10).   8 Device according to claim 1, characterized in that the pressure drop of the fluid in the distributor device (16) is between 5 and 25% of the total pressure drop of the fluid in the device (16) and the distribution grid (18).   9 A system for uniformly distributing a fluid material in a catalyst bubbling bed of a reactor, said assembly being characterized by comprising (a) a pressure chamber (12) formed at the bottom of the reactor and delimited by the lower end and the side walls of the reactor as well as   by a distribution grid (18) placed under the boiling bed 2532859-   lonnant in the reactor, (b) a conduit (10) entering the chamber   under pressure and intended to initially transmit the   fluid in the chamber under pressure, and (c) a distribution device (16) placed at the   lower end of the pressure chamber (12) and   associated with the conduit (10) with which it communicates, so that the splitter device mixes a gas and a material   liquid transmitted through the conduit into the chamber under pres-   sion and is arranged so that, in combination with   the distribution grid 7 ensures a sensible distribution   uniformly the gas-liquid mixture returned to the high in the bubbling bed.   Assembly according to claim 9, characterized in that the duct (10) has at least one fin (36) of   rectification of current placed upstream of the device   diverter. 11 assembly according to claim 9, characterized in that the distribution grid (18) has several vertical tubes (26) whose upper end is covered by a cap (28).   12 The assembly of claim 9, characterized in that it comprises a ring-shaped bubbler device (40) placed in the pressure chamber under the distribution grid (18) and above the device splitter (16).   13 Uniform distribution of a material   fluid in a bubbling bed of a reactor, said reactor   seems to be characterized in that it includes -   (a) a pressure chamber (12) formed at the bottom of the reactor and delimited by the lower end and the side walls of the reactor and by a distribution grid (18) placed under the bubbling bed in the reactor, ( b) a conduit (10) entering the pressurized chamber to flow fluid first downward into the pressure chamber, and (c) a baffle nozzle (16) rigidly attached to the end internal duct (10), the nozzle having at least two substantially parallel deflectors (30, 32, 34) spaced from each other, the inner deflector (32)   being formed of a solid plate, and at least one other   flector (30, 34) having a central orifice and being located upstream of the deflector formed by a solid plate,   the deflector nozzle (16) mixes a gas and a   liquid in the pressurized chamber and is arranged so that, in combination with the distribution grid, it ensures a substantially uniform distribution of the gas-liquid mixture originating in the the bubbling bed.   Assembly according to Claim 13, characterized in that the spaced deflectors (30, 32, 34) form a   angle of 45 to 90 with the axis of the inner end of the con- duit (10).   An assembly according to claim 13, characterized in that the baffle nozzle (16) is placed in the center of the pressure chamber (12), the axis of the conduit (10) penetrating into the pressure chamber at an angle of 45 to 90 with the vertical central axis of the chamber under pressure and reactor.   Assembly according to Claim 13, characterized in that the nozzle (16) comprises three circular plates   forming deflectors (30> 32,34), the first upper plate   upper (30) having a central orifice, the second intermediate plate (34) having a central orifice smaller than that of the first upper plate, and the third   lower plate (32) being full.   Assembly according to claim 13, characterized in that the first upper plate (30) has a central orifice whose diameter is between 0.6 and 0.75 times   the internal diameter of the duct (10), and the intermediate plate   diaire (34) has a central orifice whose diameter is   taken between 0.4 and 0.5 times the internal diameter of the duct (10).   Assembly according to Claim 13, characterized   in that the deflector plates (30, 32, 34) are separated   R 6 is a distance between 0.3 and 0.5 times the internal diameter of the duct (10 Y Y. 19 assembly according to claim 13, characterized in that the bubbler device (40) annular form   is placed in the pressure chamber (12)   below the distribution grid (18) and above the nozzle (16) with baffles.   Set of uniform distribution of a material   fluid in a bubbling bed of a reactor, said reactor   appears to be characterized in that it comprises: (a) a pressure chamber (12) formed in   the lower part of the reactor and delimited by the   lower side and the side walls of the reactor as well as by a distribution grid (18) placed under the bubbling bed in the reactor, (b) a conduit (10) entering the chamber under pressure and intended to transmit a fluid material d firstly down into the pressure chamber, and (c) a conically shaped deflector device (46) at the lower end of the pressure chamber   (12) and having its base fixed rigidly to the lower end   pressure chamber and its top (48)   towards the inner end of the duct (10), the central axis of the deflector being substantially aligned with the central axis   the inner end of the duct, so that the deflec-   conical nozzle (36) mixes a gas and a liquid material   transmitted by said duct (10) into the chamber under pres-   and in combination with the distribution grid (18),   it is intended to ensure a substantially uniform   form of the gas-liquid mixture returned upwards in the bubbling bed.   21 assembly according to claim 20, characterized in that said duct (10) contains at least one fin   Rectifier (36) upstream of the deflec- (46).