Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/0015—Feeding of the particles in the reactor; Evacuation of the particles out of the reactor
  • B01J8/0025—Feeding of the particles in the reactor; Evacuation of the particles out of the reactor by an ascending fluid
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/005—Separating solid material from the gas/liquid stream
  • B01J8/0065—Separating solid material from the gas/liquid stream by impingement against stationary members
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/1818—Feeding of the fluidising gas
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/1845—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles with particles moving upwards while fluidised
  • B01J8/1863—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles with particles moving upwards while fluidised followed by a downward movement outside the reactor and subsequently re-entering it
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/20—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles with liquid as a fluidising medium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
  • B01J8/26—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with two or more fluidised beds, e.g. reactor and regeneration installations
  • B01J8/28—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with two or more fluidised beds, e.g. reactor and regeneration installations the one above the other
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
  • B01J8/36—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed through which there is an essentially horizontal flow of particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
  • B01J8/38—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed containing a rotatable device or being subject to rotation or to a circulatory movement, i.e. leaving a vessel and subsequently re-entering it
  • B01J8/384—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed containing a rotatable device or being subject to rotation or to a circulatory movement, i.e. leaving a vessel and subsequently re-entering it being subject to a circulatory movement only
  • B01J8/386—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed containing a rotatable device or being subject to rotation or to a circulatory movement, i.e. leaving a vessel and subsequently re-entering it being subject to a circulatory movement only internally, i.e. the particles rotate within the vessel
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00008—Controlling the process
  • B01J2208/0061—Controlling the level
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00796—Details of the reactor or of the particulate material
  • B01J2208/00823—Mixing elements
  • B01J2208/00831—Stationary elements
  • B01J2208/0084—Stationary elements inside the bed, e.g. baffles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/18—Details relating to the spatial orientation of the reactor
  • B01J2219/182—Details relating to the spatial orientation of the reactor horizontal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/18—Details relating to the spatial orientation of the reactor
  • B01J2219/185—Details relating to the spatial orientation of the reactor vertical
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/18—Details relating to the spatial orientation of the reactor
  • B01J2219/187—Details relating to the spatial orientation of the reactor inclined at an angle to the horizontal or to the vertical plane

Definitions

• the present invention relates to a rotating fluidized bed device in a succession of cylindrical chambers for the catalytic polymerization, drying, impregnation, or other treatments of solid particles, in suspension in the rotating fluidized beds, from a one chamber to another, by a fluid or mixture of fluids, or for cracking, dehydrogenation or other catalytic transformations of a fluid or mixture of fluids, passing through the rotating fluidized beds, composed of solid catalytic particles passing from a cylindrical chamber to another.
• a cylindrical reactor is divided into a succession of cylindrical chambers by a succession of flat cylinders or hollow discs fixed against its side wall.
• These hollow discs comprise apertures in their center to suck the fluid passing through each chamber by rotating rapidly, and openings in their side wall to evacuate outside the reactor.
• These hollow discs are traversed by appropriately profiled passages to allow the solid particles in suspension in the fluid, rotating rapidly, to pass from one cylindrical chamber to another.
• the fluid or mixture of fluids is injected tangentially along the cylindrical wall of the reactor, generally in thin films, and, while rotating, passes radially through the reactor, from its side wall towards its center, where it is evacuated through the central openings of the hollow discs.
• the injection speed of the fluid and its flow rate are sufficient to rotate the solid particles in suspension in a rotating fluidized bed at a rotation speed producing a centrifugal force away from the central openings of the hollow discs through which the fluid is discharged and allowing to transfer them from one cylindrical chamber to another, through the passages in the hollow discs, despite the slight slight difference in pressure between these cylindrical chambers.
• the fluid is fed by one or distributors outside the reactor, in order to distribute it properly to the injectors located in the various cylindrical chambers. It is then evacuated, through the hollow discs, by one or more fans or compressors, which suck it through one or more collectors, outside the reactor and connected together, in order to regulate the pressures inside the fans. different cylindrical chambers.
• the fluid can then be recycled, after a suitable treatment, for example cooled or heated, by the same distributors or other distributors, in the same or subsequent cylindrical chambers. It can be recycled several times in the same cylindrical chambers or in successive cylindrical chambers.
• the solid particles are generally introduced at one end of the reactor and then transferred from one cylindrical chamber to the other, thanks to their rotational speed and to the profile of the passages through the hollow discs. They are usually discharged at the opposite end of the reactor.
• a device for recycling solid particles may be provided outside the reactor.
• the present invention may comprise, to improve the efficiency of the energy transfer between the fluid and the particles.
• the solids baffles suitably profiled and disposed near the fluid injectors, to allow mixing of the fluid with a limited amount of solid particles and to channel the fluid to prevent or reduce its expansion into the reactor before it transferred a significant amount of its kinetic energy to these solid particles.
• This device makes it possible to use fluids that are much lighter than solid particles and to inject it at high speed into a reactor of
• the present invention may comprise sets of helical coils or transverse fins, inclined or helically wound and fixed along the cylindrical wall of the cylindrical chambers, to use a portion of the energy
• the reactor can be horizontal. In this case the rate of injection of the fluid into the reactor and its flow must be
• the recesses can be slightly offset downwards in order to better center them with respect to the approximately cylindrical surface of the fluidized bed.
• This method makes it possible to increase the speed difference between the solid particles and the fluid without reducing the density
• This method allows residence times of the particles in the reactor, short or long, depending on the size of the passages between the cylindrical chambers, and the resistance to rotation of the fluidized bed can be low because the injection of the fluid into thin films along the side wall of the reactor reduces the friction of the solid particles on this wall.
• This method is particularly advantageous when the volume of the circulating fluid is very high, because the central evacuation devices of the fluid by hollow discs can allow very large flow of the fluid with a minimum of resistance and the distributors and collectors of the fluid, being outside the reactor, can have large diameters without reducing the space available for the fluidized bed inside the reactor.
• the hollow discs can support the cylindrical wall of the reactor, which makes it possible to have thin walls, cut longitudinally, to form slots through which the fluid can be injected and to facilitate disassembly.
• the distributors, the collectors and the reactor can form a compact, easily transportable assembly.
• D can also be used for the catalytic copolymerization, bi or multimodal, particles suspended in a succession of active fluids of different compositions.
• FIG. 1 shows a diagrammatic view of a section of a vertical cylindrical reactor whose section of its cylindrical lateral wall (1) is seen on each side of its cylindrical axis of symmetry (2).
• the fluid (10) After passing through the approximately conical surface of the fluidized bed, whose section (9) is seen, the fluid (10) penetrates into the central openings of the hollow discs (3), which can be surmounted by tubes (11) to prevent the solid particles penetrate during stops and that can be widened (12) around their central openings to facilitate the entry of the fluid.
• the fluid (13) is then discharged through the openings (14) of the side edges of the hollow discs which can be widened (15) around these openings (14) to facilitate the outlet of the fluid by the tube assemblies (16).
• the fluid can be recycled several times before being discharged in (20), through the lower part (17.1) of the collector, by the fan or compressor (18.1).
• the average recycling number of the fluid is approximately equal to the ratio of the flow rates of the fans (18) and (18.1).
• the injection speed of the fluid is influenced by the hydrostatic pressure generated by the weight of the fluidized bed in each zone.
• the slots (7) through which the fluid is injected can be adequately profiled, as symbolized by their trapezoidal shape, and they can be equipped with obstacles distributed appropriately to reduce the injection speed in their upper part.
• Control valves (22) can also be used to adjust the speed and the proportion of the fluid (23) injected at the different levels of the cylindrical chambers.
• a control valve (24) can also adjust the output flow of the fluid (20).
• the introduction of the solid particles (25) can be done in the bottom of the reactor by the tube (26) by suitable means, such as gravity, a helical screw or a jet of fluid.
• the reactor being divided by the hollow discs into several cylindrical chambers, from Z1 to Z3, they rise from one chamber to the next, through the passages (27) which are arranged through the hollow discs. They are removed from the last cylindrical chamber, Z3, at the top of the reactor, in (29), by the tube (30) by suitable means.
• Other outlets, (30.1) may be provided, for example in the bottom of each chamber, to quickly empty the reactor.
• the amount of particles transferred depends on the rotational speed of these particles, which must be sufficient to overcome the hydrostatic pressure of the fluidized bed above the passage.
• a control valve 22
• the energy injected into the top of this chamber is increased and thus the speed of rotation is increased.
• solid particles and thus their transfer to the upper zone By slaving these valves to level detectors on the surface of the fluidized beds of each chamber, these surfaces can be stabilized between the passages and the central entrance of the hollow disks. This makes it possible to locate these passages against the side wall of the reactor, where the concentration of the particles is highest and thus to reduce the amount of fluid entrained with these solid particles.
• the amount of solid particles transferred from one zone to another may also vary depending on whether the passages are more or less immersed in the fluidized bed of the lower cylindrical chamber, which makes it possible to stabilize the surface of the fluidized bed at the top of each cylindrical chamber along these passages.
• the fluidized bed may be thicker or thinner depending on the distance of these passages from the side edge of the reactor.
• the emptying of the reactor can be done by lateral outlets at the bottom of each zone and its initial filling can be done from below, by closing the supply of the fluid by the tubes (6) of the upper cylindrical chambers that are not filled during the filling. a lower cylindrical chamber, to prevent most of the fluid from passing through the empty chambers. It can also be done through the feed tubes of the recycled fluid, if the size and nature of the solid particles allow it or from above if the orientation of at least one passage by hollow disk allows it.
• the thin film of fluid coming out of the injectors has a tendency to widen very rapidly and therefore to slow down before it has been able to transfer enough rotational kinetic energy to the solid particles.
• properly shaped side baffles may be attached more or less parallel to the side wall of the reactor, near the outlets of the injectors, in order to mix a small volume of solid particles with the fluid injected into the spaces or corridors. located between these side baffles and the reactor wall. These lateral deflectors prevent the fluid from expanding, and therefore slowing down, before it has transferred a sufficient portion of its kinetic energy to the solid particles, inside these spaces or corridors, which must have a profile and a length adapted to the objectives.
• Figure 2 is a cross section of the reactor for viewing this fluid injection pattern. It shows the section of the side deflectors (32), perpendicular to the plane of the figure and along the sections of the side wall (1) of the reactor, radius (33), in order to define with this side wall a space or corridor, generally convergent then diverge, whereby the fluid, shown schematically by the arrows (4), injected by tubes or nozzles (6), width (34), must pass. It also shows the circular section of the surface of the fluidized bed (9) radius (35). The solid particles are shown schematically by the small arrows (37), indicating their direction of movement.
• the access tubes to the hollow discs are connected by central deflectors, perpendicular to the plane of the figure, of section (38), of curvature (39), delimiting slits through which the fluid (10) is sucked towards the central openings of the hollow discs, and to better separate the fluid particles.
• Concentrated flows of solid particles penetrate into these spaces or corridors, generally converging and then diverging, by passages or corridors of access, of width (42), located between the wall of the injectors (6). and the side baffles (32) at a rate which is about the average rotational speed of the solid particles in the reactor.
• These concentrated flows of solid particles are diluted by mixing with the injected fluid, which gives them a substantial part of its kinetic energy, and thus increases their momentum, in these spaces or corridors between the walls of the reactor (1) and the deflectors lateral (32). Then the solid particles are mixed with the other solid particles of the fluidized bed by yielding the amount of movement acquired.
• these spaces or corridors are first convergent, to reach a minimum width (43), and then divergent, to reach the output width (44). They can also have a constant width. In this case, the fluid is slowed down as the solid particles and the fluid that accompanies them accelerate. In general, the dimensions of these spaces or corridors must be established according to the operating conditions and the objectives of kinetic energy transfer.
• transverse deflectors perpendicular to the cylindrical wall of the reactor, such as rings, can divide the space delimited by the fins and the side wall of the reactor, to guide the fluid and the particles in the desired direction , generally horizontal or inclined upwards, until the fluid is mixed with the particles, as shown in Figure 3.
• FIG. 3 is an axonometric projection of a piece of side wall (1) of the reactor, making it possible to better visualize an example of injectors (7) of fluid, with their lateral deflectors (32) and rings (46) serving transverse deflectors preventing the fluid from rising along the reactor wall. It also shows, in dashed line, the entries of the fluid supply tubes (6), located behind the side wall of the injectors, and, hatched, the sections of the injector outlets (7), in the foreground. .
• the arrows (4) and (41) respectively indicate the directions of the fluid flows and solid particles penetrating or leaving the converging and diverging spaces between the side baffles (32) and the side wall (1) of the reactor.
• the transverse deflectors illustrated by large rings (46), may be hollow, forming a kind of circular nozzles and connected to the outside of the reactor by one or more feed tubes for distributing the fluid in a succession. of injectors arranged along them, to reduce the number of tubes passing through the wall of the reactor, necessary to injector supply, which may be desirable when the pressure in the reactor is high
• transverse baffles may also be successions of helical turns, forming an upward spiral, continuous or discontinuous, within each cylindrical chamber or be a succession of fractions of helical turns or transverse fins, grouped at one or more same levels chambers, the upper edge of a fraction of turn or fin overhanging the lower edge of the next, in order to raise the solid particles along the wall of the reactor to reduce the difference in thickness of the fluidized l and the pressure differences along this wall between the top and the bottom of the different cylindrical chambers of the reactor
• FIG. 4 is the projection of a half-cross section of a cylindrical chamber, where successions of quarter turns of helical turns (46) form either a continuous spiral making three turns inside the chamber, or three sets of four helical turns located at the same levels of the chamber and succeeding each other the 90 °, the upper edge of a quarter of a turn overhanging the lower edge of the following
• FIG. 5 shows the section of a passage (27). It shows the section (3) of the two parallel plates forming the hollow disk and its interior space (50) through which the fluid passes radially, that is to say perpendicular to the plan of the figure, to leave the reactor
• the solid particles are represented by the black points which move in the direction of the arrows (51) They cross the hollow disk while skirting the inclined walls (52) of the passage They are prolonged by deflectors (53) on each side of the hollow disc in order to facilitate the transfer of the particles from the bottom upwards, in the direction of their rotational speed
• deflectors (53) can be extended by spirals whose section (46) is seen, In order to facilitate the ascent of the solid particles FIG.
• FIG. 6 is a transverse flow diagram of the solid particles along a half longitudinal section of a cylindrical chamber similar to that shown in FIG. s the lateral and central deflectors
• the section (1) of the reactor wall, its cylindrical axis of symmetry (2), the feed tubes (6) of the fluid (4) in the section injectors (7) are recognized.
• the fluid (4) injected into the cylindrical chamber, perpendicularly to the plane of the figure, passes through the surface of the fluidified sectional area (9) and penetrates (10) into the inlet tubes (11) of the hollow discs (3) from which it is sucked by the outlet tubes (16)
• the solid particles whose rotational speed perpendicular to the plane of the figure is of an order of magnitude greater than the transverse velocities, enter the cylindrical chamber through the passage lower, (27e), has a flow Fe and they come out through the upper passage (27s) to the flow Fs If the latter is greater than the inlet flow, Fe, the chamber gradually empties its solid particles and the surface of the fluidized bed approaches its side wall, which automatically reduces the output flow Fs
• Another way to adjust the level of the fluidized bed is to slave the injection rate of the fluid in the upper part of the chamber to a detector of particles, which can be place along the bottom wall of the hollow disk and which, depending on the position of the surface of the fluidized bed, increases or decreases this flow rate and therefore
• the pressure difference between the top and the bottom of the cylindrical chamber can cause differences in injection speeds of the fluid as a function of the height of their injection. These differences generate differences in rotational speeds of the solid particles.
• the difference in pressure between the two faces of the hollow discs and more particularly between the inlet and the outlet of the passages through these hollow discs and the friction slow down the solid particles which are transferred from one chamber to the other and therefore slow down the speed of rotation of the solid particles in the bottom of the next cylindrical chamber.
• the lower rotational speed of the solid particles and therefore of the centrifugal force in the bottom of the cylindrical chambers causes both a slight decrease in the pressure along the side wall and a slight increase in the thickness of the fluidized bed.
• the solid particles are slowed down by the friction and the increase of their potential energy while climbing along the upper surface of the helical turns, which causes the same type of internal circulation between the sets of helical turns.
• These successive slowdowns in the speed of rotation of the solid particles and their internal circulation increase the amount of energy that the fluid must transfer to the particles, requiring an efficient transfer of momentum and a very high fluid flow, which is well suited to this process. .
• Approximately the internal circulation can be estimated by dividing the fluidized bed into rings, which are assumed to have mean rotational velocities, and determining the pressure and thickness deviations between these rings to deduce the importance of this circulation, and then apply conservation. the amount of motion to determine by successive approximations the average equilibrium rotation speed of these rings. These speeds depend inter alia on the amount of movement transferred by the fluid to the solid particles.
• this amount of motion depends on the rotational speed of the fluid which is more related to the proportions of the cylindrical chamber and the flow rate of the fluid than to its injection speed.
• the variation of pressure inside a convergent space makes it possible to transfer to the solid particles a quantity of movement in relation to its kinetic energy and therefore its injection speed, which favors this type of supply when the The ratio between the fluid injection rate and the desired rotational speed of the solid particles must be very high because of the high ratio of particle density to fluid.
• This device can adapt to different schemes, according to the different processes.
• Figure 7 illustrates a simplified schematic, similar to Figure 1, slightly modified to allow bimodal or multimodal co-polymerization of solid particles as a catalyst, suspended in fluids or mixtures of active fluids, containing the monomer and the comonomer (s), such as, for example, the bimodal catalytic copolymerization of ethylene with hexene.
• the reactor (1), its cylindrical axis of symmetry (2), the hollow sections of the hollow discs (3) separating the reactor into two sets of two successive cylindrical chambers from Z1 to Z2 and Z3 to Z4 are recognized therein. feeding tubes
• the number of cylindrical chamber assemblies and the number of cylindrical chambers per set may vary. It depends on the size of the reactor and the polymerization objectives.
• the polymer particles, symbolized by the black dots, emerging from the top of the reactor through the tube (30) are introduced into a recycling tube which may be a purification column (61), through which the fluid injected in (4.1) passes. ,
• the polymer particles are then recycled through the tube (26) to the bottom of the reactor. After having traveled a certain number of cycles, they (29) are evacuated by tubes (30.1), which can be arranged along the side walls of the various cylindrical chambers.
• the supply of fresh monomer, such as ethylene, can be introduced: partly in (4.1), at the bottom of the column
• the co-monomer (63), such as hexene, may be sprayed into fine droplets on the surface of the fluidized beds of one or more upper cylindrical chambers by injectors (64), which pass through the hollow discs and the catalyst can be introduced by a suitable device (65) into one of the cylindrical chambers.
• injectors (64) which pass through the hollow discs and the catalyst can be introduced by a suitable device (65) into one of the cylindrical chambers.
• Other active components, such as hydrogen, and other monomers can be introduced into one of the recycle circuits, and their excess can be eliminated
• non-active cooling fluids such as propane or isobutane, may be sprayed into fine droplets on the fluidized beds in the same manner as the comonomer.
• the accessories of controls, purifications, etc. including the possibility of cooling the hollow discs, the purification column and other surfaces arranged inside the chambers, are not described. They can be defined according to the polymerization objectives by the people controlling the fluidized bed polymerization processes.
• FIG. 8 illustrates a simplified diagram, similar to that of FIG. 7, slightly modified in order to allow the catalytic conversion of a fluid or mixture of fluids, in a rotating fluidized bed containing solid catalytic particles, for example, cracking. catalytic light olefins.
• the process fluid (4) is injected, if necessary preheated in the or distributors (5) that feed the set of lower cylindrical chambers, Zl and Z2. It is evacuated from these chambers by the collector (s) (17), to be reheated in the heater (19), and recycled by the distributor (s) (5.1) in the set of upper cylindrical chambers, Z3 and Z4, d where it is sucked through the collector (s) (17.1) by a single compressor (18) to be transferred to (20) to suitable processing units.
• the equilibrium level of the surface (62) of the fluidized bed of the column (61) is that which gives a hydrostatic pressure sufficient to allow the regenerated catalyst powder to be recycled to the desired flow rate. This recycling can be facilitated by the injection of a driving fluid, (4.2), such as water vapor.
• the series supply of the two sets of cylindrical chambers causes a significant pressure difference between the chamber Z2 and the chamber Z3, which will accelerate the catalyst particles and the fluid that accompanies them in the passage (27) connecting them.
• the ratio between the density of the fluidized bed and the fluid is very high, it is necessary not only a very high fluid flow, but also a high injection speed, it is desirable to use a suitable energy transfer device and amount of fluid movement to the catalytic particles, before the fluid has lost a substantial portion of its velocity due to its expansion in the open space of the cylindrical chambers.
• the number of rooms and sets may vary.
• the accessories of controls, purifications, etc .... are not described. They can be defined according to the objectives, by those who master the fluidized bed catalytic transformation processes.
• the outgoing fluid coming from the upper set of cylindrical chambers is at a lower pressure, which is generally favorable for the conversion of the fluid, but it is in contact with the catalyst that must be regenerated, which is unfavorable. and requires cycle times between two shorter regenerations.
• This can be avoided by adding a second compressor before the heater (19) to equalize the pressures in the two sets of cylindrical chambers, which allows to reverse the flow of fluid, ie to feed the fluid to be transformed in the upper set and remove the transformed fluid from the lower set.
• the drying of solid particles, such as cereal seeds can be done with air at a pressure close to atmospheric pressure, it is possible, thanks to this process, to make it in light units, compact and easily transportable, as described in Figures 9 to 12.
• Figure 9 shows the longitudinal section of a horizontal reactor, which can work at a pressure slightly lower than atmospheric pressure. It shows the section (1) of its wall, its cylindrical axis of symmetry (2) and the hollow sections (3) of the hollow discs which separate the reactor into five successive cylindrical chambers, from Z1 to Z5.
• the distributor (5) is traversed by a longitudinal slot, symbolized by the fine line (69) and is connected by plates, replacing the tubes (6) and schematized by the rectangle (70), to long longitudinal slots over the entire reactor length, symbolized by the rectangle (7), dividing the cylindrical wall of the reactor into two half-cylinders and designed to inject the fluid (4) perpendicularly to the plane of the figure, that is to say tangentially in the reactor.
• the fluid While rotating, the fluid passes through, at a radial velocity (8), the fluidized bed, whose surface (9) is approximately cylindrical.
• the rotation speed of the particles symbolized by the black dots, being greater in the lower part of the reactor due to gravity, the thickness of the fluidized bed is less and therefore the axis of symmetry (2.1) of the surface of the fluidized bed is slightly lower than the axis of symmetry (2) of the reactor.
• the distance between these two axes, ⁇ which is approximately equal to half the thickness difference between the top and bottom of the fluidized bed, is approximately ⁇ ⁇ E.
• Tubes (71), passing through the ends or covers of the reactor, can also evacuate the fluid centrally. Then a portion of the fluid is discharged at (20) through a control valve (24). Its flow is approximately equal to the flow rate of the fluid supplied in (4). The remainder of the fluid is treated, for example, dried with a condenser and / or heated, at (19), and then recycled (23) through the opposite end of the dispenser (5). It should be noted that, in the scheme described above, the fluid can be recycled on average several times before being discharged, if the flow rate of the recycling fluid (23) is several times greater than the feed rate (4). and therefore also to the evacuation flow (20), but due to its mixing in the fan (18) a small fraction of the fluid will be evacuated as soon as it passes into the reactor. This can be avoided by using a second fan, (18.1) as shown in the diagram of Figure 1.
• the solid particles (25) are introduced into the reactor through the tube (26) by suitable means and are transferred from one chamber to another through the passages (27).
• the particles will first fill the first cylindrical chamber, Z1, until the level of the surface (9) of the fluidized bed reaches the level of the first passage (27). Then the particles can begin to fill the second cylindrical chamber and so on until the level of the last cylindrical chamber, Z5, arrives at the exit aperture of the particles (29) through the tube (30). allowing their exit from the reactor.
• the transfer rate depends on the rotational speed of the solid particles, the dimensions of the passages and their profile and the differences in level of the surface of the fluidized bed from one chamber to another. The latter can be accentuated or diminished by tilting the reactor. Particle rotation is ensured by the transfer of momentum from the fluid to the particles, in order to compensate for energy losses due to turbulence, friction and their transfers in the reactor and from one chamber to another . This amount of movement can be increased by placing side deflectors, (not shown in this figure) adequately profiled in front of the injectors. Energy losses can be minimized by taking care of the internal aerodynamics of the cylindrical chambers.
• the emptying of the reactor in case of malfunction, can be provided by openings arranged in the bottom of each zone and a filter or particle separator can be installed upstream of the fan (18) or the outlet (20) to avoid send solid particles downstream of the installation.
• the central openings of the hollow discs can be connected by central baffles, such as those (38) described in Figure 2, and their inputs can be located in the upper part of the reactor to minimize the risk of particle aspiration, especially during untimely stops.
• FIG. 10 represents the view of a section crossing a hollow disk, along the plane AA 'of FIG. 9, for a reactor having two distributors and two collectors and forming therewith a compact assembly that is easily transportable and designed to be easily removable. It shows the section (1) of the side wall of the reactor, the section (5) of two distributors, their longitudinal slots (69), perpendicular to the plane of the figure, and plates (70) for injecting the fluid (4) through the slots (7) passing longitudinally (perpendicular to the plane of the figure) the reactor wall, dividing it into two half cylinders. They are preferably arranged at approximately the same height on each side of the reactor, so that the flow rate of the fluid passing through them is not affected by differences in hydrostatic pressure inside the fluidized bed.
• the enlargement (12) of the hollow disc around its central opening is delimited by two circles (76), in fine lines, and the two enlargements (15) at the periphery of the disc, around its lateral openings, are delimited by the curves (77), in fine lines.
• the inside of the hollow disk being visible, we can see the section (78) of spars connecting its two parallel walls to maintain the spacing, to increase the rigidity of the assembly and to guide to the openings in its side wall (79) the fluid (80) which rotates rapidly as it enters the hollow disk.
• the fluid (13) then leaves the hollow disc and enters the two section manifolds (17) through the nozzles, which is seen a face (16) and whose end (81), in fine line, is welded to the manifold (17) and whose other end, which enters the transverse slot of the reactor, is welded to the side wall of the reactor and enters the interior of the hollow disc through the slots in its side wall (79).
• the circular end (82) of the nozzle (16) is pressed against the bottom wall of the hollow disk and the lateral sides of the nozzles, whose sections (83) are seen, are folded at their end (84) to facilitate their insertion. in the openings of the side wall of the hollow disc, during assembly of the reactor.
• Triangular spars (85) connect the opposing walls of the nozzles to increase their rigidity and their suitably profiled ends (86) penetrate the hollow disc to guide these nozzles within the disc when assembling the two parts of the disc. reactor.
• the ends (82) and (84) of the nozzles (16) have dimensions that allow them to fit easily and sufficiently tightly into the side openings of the hollow discs.
• the passages which allow the transfer of particles from one zone of the reactor to the other through the hollow disk are arranged, for example, along the edges of the hollow disk, (27.1), and closer to its center, ( 27.2). They are delimited by the walls (87) perpendicular to the plane of the figure and the inclined walls (52) which guide the solid particles moving in the direction (89), from the zone of one side of the disc to the zone of the 'other side. If a transfer of solid particles in both directions is desirable to obtain reflux, for example heavier particles, some passages, for example near the reactor wall, may be inclined in the opposite direction.
• FIG. 11 is an enlargement of the fluid injection device shown in FIGS. 9 and 10. It shows, in hatched form, a piece of the section (1) of the side wall of the reactor, the distributor (5), the plates (70) and (73) connecting the longitudinal slot (7), perpendicular to the plane of the figure, in the wall of the reactor to the longitudinal slot (69) of the distributor (5) of the fluid (4), and in fine lines, the fastener (74) which makes it possible to assemble the lower part of the reactor, on the left of the figure, with its upper part, on the right, and the section of the insert (75) which ensures the spacing of the plates (73 ) one of which is an extension of the wall (1) of the upper part of the reactor, on the right, and the other is welded to the lower part of the reactor, on the left.
• the side wall (79) of the hollow disc and a passage (27.1), along the lateral edge of the hollow disc, delimited by a side wall (87) and inclined walls (88) which guide the flow of particles (89) of the area below the hollow disk at the area above the hollow disk are also visible in this figure.
• Figure 12 shows the view of a section, along the plane BB 'perpendicular to Figure 10, the nozzle connecting a hollow disk to a collector. It shows the outer surface of the collector (17), the inner surface of the lateral side (79) of a hollow disk and the section (3) of its two parallel walls, the two circular ends (82) and the ends (84). ) triangular side edges of the nozzle, folded and shaped to fit into the opening (14), arranged in the side wall (79) of the hollow disc between its walls (3), the triangular beams (85) with their ends (86) suitably profiled to facilitate the embedding of the nozzle in the opening of the hollow disc and finally the upper and lower wall (16) of the nozzle which intersects the collector (17) along the weld lines (81).
• particle rotation rates depend on a combination of factors such as turbulence and viscosity of the fluidized bed, which depend on the nature of the solid particles and the aerodynamics inside the cylindrical chambers, the examples which follow are given only as an indication.
• a unit of industrial size may, for example, have cylindrical chambers of 3 m diameter and 1.8 m high. If the ethylene pressure is about 25 atmospheres and the particle concentration in the fluidized bed is about 35%, the ratio of the density of the fluidized bed and the fluid is about 11. Central openings of the disks Hollow 0.8 m diameter can easily evacuate a stream of ethylene recycled 5 ⁇ rVsec per cylindrical chamber, or about 500 tons per hour.
• an average fluid injection rate of about 20 m / sec and an efficient transfer of the momentum of the fluid to the polymer particles can make it possible to do so rotate at an average speed of more than 6 m / s, sufficient to obtain a vertical rotating fluidized bed.
• the thickness at their bases may be about 0.9 m, giving a fluidized bed volume of nearly 7 m 3 per cylindrical chamber, or about 2.3 tons of polyethylene.
• the use of helical spirals or other suitable means makes it possible to increase the thickness at the tops of the chambers while decreasing it at their bases, which can allow a volume of the fluidized bed of 7.5 m 3 or 2.5 tons of polyethylene, while reducing the differences in pressures, velocities and residence time of the fluid in the fluidized bed between their bases and their vertices.
• the average residence time of the polymer particles in each cylindrical chamber is about 1 minute and that of the fluid in the fluidized bed is 1.5 seconds.
• the reactor comprises 10 cylindrical chambers, which can be grouped into two or more sets having separate recycling circuits, to obtain a composition of the bi or multimodal polymer particles, the total volume of recycled fluid is 50 m 3 / sec, approximately 5,400 tonnes per hour, which makes it possible, without the aid of refrigerant fluids, to cool a production of at least 50 tonnes of polymer per hour with an average residence time of the particles of 30 minutes, allowing them about 3 complete cycles on average, which ensures a reasonable homogeneity of the polymer particles, while limiting the transfer of undesirable fluids between the different parts of the reactor.
• the amount of polymer particles transferred from one chamber to another can be increased by increasing the dimensions of the passages, which also increases the amount of fluids transferred from one set of rooms to another and can therefore reduce their differentiation.
• the volume of ethylene supplying the reactor is approximately 0.5 m 3 / sec, ie approximately 6 times the volume of fluid transferred with the particles from one chamber to another and thus also in the purification column. (61), it is easy to purge the particles of this hexene-containing fluid using a portion of this ethylene in this column, given the possibility of having a lower concentration of hexene in the upper cylindrical chamber if hexene is sprayed only in the lower cylindrical chambers of the upper assembly.
• the lower set of cylindrical chambers contains a high concentration of hydrogen to decrease the molecular weight of the high density polyethylene produced therein, a small amount of this hydrogen is transferred to the upper set (s) of the reactor together with the polymer particles.
• a hydrogen absorber which can be inserted in the fluid recycling circuit (s) of the at least one higher assembly.
• the surface of the fluidized bed of about 12 m 2 per chamber, ie 120 m 2 in all, for an average thickness of the fluidized bed of about 0.6 m and the centrifugal force, which allow a flow of fluid as well. high and a fluid residence time in the fluidified bed as short.
• the pressure difference between the inlet and the outlet of the reactor is relatively small, making it possible to limit the energy expenditure necessary for recycling the fluid.
• the centrifugal force and the direction of fluid displacement essentially tangential to the surface of the fluidized bed, allow a high difference in velocities between the fluid and the particles, in order to ensure better heat transfer, without much diminishing the density fluidized bed.
• the catalytic cracking of gasoline olefins from catalytic crackers is carried out at high temperature and at low pressure, close to atmospheric pressure. It is very endothermic, which justifies working in two successive passes with intermediate reheating, which requires the circulation of considerable fluid volume.
• the catalyst is progressively coated with carbon, and all the more quickly that the fluid to be cracked is heavier, which justifies a circulation of the catalyst with continuous regeneration.
• the average cycle time between two regenerations depends on the working conditions. It can be less than an hour to several hours. For example, as an indication for setting orders of magnitude, an industrial reactor can have cylindrical chambers of 1.6 m diameter and 1.5 m high.
• a recycled fluid flow rate of 2.4 mVsec injected at an average speed of 50m / sec, can rotate the catalyst particles at a rotational speed greater than 4 m / sec, sufficient to obtain a vertical rotating fluidized bed.
• the pressures and the thicknesses of the fluidized bed between the top and the bottom of the chambers can be sufficiently high, it is desirable to equip them with ascending helical spirals or other devices making it possible to reduce them. .
• the reactor has two sets in series of four cylindrical chambers each, which gives it a height of more than 12 meters, given the thickness of the hollow discs necessary for the evacuation of the fluids, it can crack about 200 tons per day. hour, if the density of the heated fluid is 6 gr / liters.
• the pressure difference between the inlet and the outlet of each set of cylindrical chambers, necessary to compensate for the hydrodynamic pressure of the fluidized bed and to inject the fluid at the desired speeds, may be less than a quarter of the atmospheric pressure. If the pressure drop in the heating furnace is sufficiently low, the supply of the two parts of the reactor being in series, the pressure difference between these two parts may be less than 50% of the atmospheric pressure, compared to the pressure hydrostatic fluidized bed in the recycle column (61), which can be close to atmospheric pressure for a height of 11 m, which is sufficient to recycle the regenerated catalyst particles.
• a horizontal reactor as described in Figures 9 to 12, forming with these accessories a set the size of a container easily transportable, may be 1.8 m in diameter and be divided into 6 cylindrical chambers 0.5 m wide.
• the wet grains (25) are introduced through the tube (26) into zone Z1. They are heated and dried by recycled air, which is heated by the exchanger (19) and possibly dried, if necessary, by a condenser not shown.
• the grains are transferred from one cylindrical chamber to the other until the last chamber, Z6, where they are cooled by the fresh air (6) which they preheat while completing their drying before going out (29) by the tube (30).
• the air is warmed dried and recycled in the other zones, a number of times equal to the ratio of the total flow of the fan and the flow of the air evacuated in (20).
• Air and grain and air flow can be relatively high, which reduces the time required for drying.
• the grains being cooled by fresh air before leaving the reactor and their residence time in the reactor being relatively short, they can be heated to slightly higher temperatures than in a conventional dryer.
• the moist air being slightly cooled by the grains it preheats before leaving the reactor, the use of calories is very effective. This efficiency can be improved by using a second, smaller fan, which directly vents the air coming out of the
• First cylindrical chamber which served to the preheating of grains and which can be isolated by a separation in the first hollow disk, without it being mixed with the air from the other cylindrical chambers.
• small secondary passages (27.1) along the side wall of the reactor can provide a preferential transfer of the heavier grains, and therefore the most difficult to dry, in the opposite direction, in order to increase their residence time in the reactor.
• the fluidized bed containing the grains in suspension has a bulk density of 300 grams per liter
• the ratio of this density and the ambient air is about 230, which requires very high air flow and injection speed.
• an air flow of 2 mVsec per chamber, ie more than 9 tonnes per hour per chamber, injected at around 40 m / sec and an efficient transfer of momentum from the air to the grains can give grain rotation of more than 6 m / sec, giving a difference in thickness between the top and bottom of a fluidized bed of average thickness of 30 cm, less than 12 cm.
• the total air flow rate of 12 mVsec can be fed by a fan into two distributors 0.65 m in diameter and discharged by two collectors 0.7 m in diameter, the central openings of the hollow discs being able to be less than 0 , 6 m in diameter.
• the volume of the fluidized bed is about 700 liters per chamber, or 4.2 m 3 in all, for a surface of more than 11 m 2 .
• the grain transfer from one chamber to another is 20 liters per second, or about 20 tons per hour, their average residence time in the dryer is about 3.5 minutes.
• Their degree of drying depends on the degree of humidity and the temperature of the air which can be warmed, among others, by the cooling of the fan motor, and can pass through a condenser, but in a general way it is faster than in an ordinary dryer, given the great difference in velocities between air and grains, obtained thanks to their tangential direction and centrifugal force.
• the capacity can be doubled by doubling the length of the reactor and using an additional fan on the grain outlet side to avoid having to increase the diameter of the distributors and collectors.

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