Charge injection device for an FCC unit

Abstract

The invention relates to an injection device (10) configured to atomize a liquid into droplets using a gas, comprising a hollow tubular body (12) of longitudinal direction (X). An internal wall (13) defines a first zone referred to as a contact zone (Z1) and a second zone (Z2). The device (10) is notably provided with an atomizing element (18) mounted on an opening (19) of the body situated facing an opening (17) for injecting a liquid, comprising a tubular pipe (20) for conveying gas into the first zone (Z1), and a target (21) situated at the centre of the pipe. The body has an internal cross-section that varies continuously or is constant over its entire length (for example the shape of a simple cylinder) and of which the internal wall is provided, between the zones (Z1) (Z2), with at least one chicane (26i, 26i) projecting from the internal wall towards the inside of the body.

Claims

1. An injection device configured to atomize a liquid into droplets using a gas, comprising a hollow tubular body extending in a longitudinal direction (X) and of which an internal wall defines a first zone referred to as contact zone (Z1) and a second zone (Z2) situated downstream of the first zone with respect to a direction in which the liquid and the gas circulate inside the body, a first gas introducing element for introducing a gas into the first zone (Z1) in the longitudinal direction, the said gas introducing element being mounted on a first opening of the body, at one end of said body in the longitudinal direction, a second liquid introducing element for introducing a liquid into the first zone (Z1) in a direction perpendicular to the longitudinal direction, mounted on a second opening of the body, an atomizing element mounted on a third opening of the body situated facing the second opening, and comprising: a tubular pipe for conveying gas into the first zone (Z1), situated facing the liquid introducing element, and a target situated at the center of the pipe, the pipe and the target extending in a direction perpendicular to the longitudinal direction, the target having an impact surface at one end of the pipe opening into the first zone (Z1), in alignment with the first gas introducing element, an end element comprising at least one outlet orifice for discharging the atomized liquid, mounted at one end of the body that is the opposite end to the first gas inlet opening, characterized in that the body has an internal cross-section that varies continuously or is constant over its entire length and in that its internal wall is provided, between the first and the second zone, with at least one chicane projecting from the internal wall towards the inside of the body, wherein the at least one chicane has a curved wall with a concavity of the one or more chicanes oriented toward the outlet orifice.

2. The injection device of claim 1, characterized in that the said at least one chicane is configured so that, in each plane perpendicular to the longitudinal direction of the body containing the said chicane, the chicane extends over the entire periphery of the internal wall.

3. The injection device of claim 1, characterized in that the said at least one chicane is configured so that, in each plane perpendicular to the longitudinal direction of the body containing the said chicane, the chicane extends over just part of the periphery of the internal wall.

4. The injection device of claim 2, characterized in that the said at least one chicane is selected from: a chicane configured in such a way that the orthogonal projection of the chicane onto a plane perpendicular to the longitudinal direction of the body extends over just part of the periphery of the internal wall in the said plane of projection a chicane configured in such a way that the orthogonal projection of the chicane onto a plane perpendicular to the longitudinal direction of the body extends over the entire periphery of the internal wall in the said plane of projection.

5. The injection device of claim 3, characterized in that the said at least one chicane defines a wall one edge of which is secured to the internal wall along a segment of a curve.

6. The injection device of claim 1, characterized in that the said at least one chicane defines a wall one edge of which is secured to the internal wall along a line extending in a plane perpendicular to the longitudinal direction of the said body.

7. The injection device of claim 1, characterized in that the said internal wall is provided with a plurality of disjointed chicanes.

8. The injection device of claim 7, characterized in that at least one chicane is spaced away from at least one other chicane in the longitudinal direction of the body.

9. The injection device of claim 7, characterized in that each chicane is angularly offset from the other chicanes by rotation about an axis parallel to or coincident with the said longitudinal direction (X).

10. The injection device of claim 9, characterized in that the orthogonal projection of the chicanes onto a plane perpendicular to the longitudinal direction of the body extends over the entire periphery of the internal wall, with the projections overlapping or being juxtaposed.

11. The injection device of claim 1, characterized in that the chicane or chicanes have a height, measured perpendicular to the longitudinal direction of the body, that is non-zero and equal to at most of the maximum internal dimension of the body perpendicular to the longitudinal direction of the body.

12. The injection device of claim 1, wherein at least one of chicanes has a height that varies over a length of the chicane.

13. The injection device of claim 1, wherein the closest chicane to the target is at a distance 1 from the target, wherein 1 is less than a diameter of the internal wall.

14. The injection device of claim 13, wherein 1 is of the diameter.

15. The injection device of claim 1, wherein the chicane includes a free edge, the free edge opposite an edge secured to the internal wall, the free edge having a rounded face.

16. The injection device of claim 1, wherein the chicane includes a free edge, the free edge opposite an edge secured to the internal wall, the free edge having a bevelled face.

Description

(1) The invention is now described with reference to the appended, non-limiting drawings, in which:

(2) FIG. 1 is a schematic depiction in longitudinal section of an injection device according to one embodiment of the invention;

(3) FIG. 2a is a view in section along the line AA of a chicane of FIG. 1, according to one embodiment;

(4) FIGS. 2b and 2c are views in section along the lines AA and BB of FIG. 1, respectively, according to another embodiment;

(5) FIG. 2d is an orthogonal projection in a plane perpendicular to the longitudinal direction X of the chicanes of the injection device of FIG. 1, according to an alternative form of embodiment;

(6) FIG. 3 partially depicts a longitudinal section of an injection device according to another alternative form;

(7) FIG. 4 partially depicts a perspective view of the open internal wall of an injection device according to another alternative form;

(8) FIG. 5 depicts a view of several chicanes along the longitudinal axis X according to another alternative form;

(9) FIG. 6 depicts a view along the longitudinal axis X according to another alternative form of one and the same chicane, and views in section in two distinct directions AA and BB which are perpendicular to the longitudinal direction;

(10) FIGS. 7 and 8 partially depict views in longitudinal section of chicanes having free edges of different shapes.

(11) In the various figures, elements that are identical bear the same references.

(12) FIG. 1 schematically depicts an injection device 10 which has a hollow tubular body 12 which extends in a longitudinal direction X.

(13) The body 12 comprises an internal wall 13 which defines a first zone Z1 referred to as contact zone, and a second zone Z2 situated downstream of the first zone Z1 with respect to a direction in which the liquid and the gas circulate inside the body (in this instance from left to right in FIG. 1).

(14) The injection device 10 further comprises: a first gas introducing element 14 for introducing a gas into the first zone Z1 in the longitudinal direction X, this gas introducing element 14 being mounted on a first opening 15 of the body, at one end of said body in the longitudinal direction X, a second liquid introducing element 16 for introducing a liquid into the first zone Z1 in a direction perpendicular to the longitudinal direction X, mounted on a second opening 17 of the body close to the first opening 15, an atomizing element 18 mounted on a third opening 19 of the body situated facing the second opening 17, and comprising: a tubular pipe 20 for conveying gas into the first zone Z1, situated facing the liquid introducing element 16, and a target 21 situated at the centre of the pipe 20, the pipe 20 and the target 21 extending in a direction perpendicular to the longitudinal direction X, the target 21 having an impact surface 22 at one end 23 of the pipe opening into the first zone Z1, in alignment with the first gas introducing element 16, an end element 24 comprising at least one outlet orifice 25 for discharging the atomized liquid, mounted at one end of the body that is the opposite end to the first gas inlet opening 15.

(15) The end element 25 is thus situated downstream of the zones Z1, Z2.

(16) The openings 15, 17, 19 of the body 12 open into the first zone Z1, also referred to as contact chamber.

(17) Inside the body 12, the fluids circulate from the inlet openings 15, 17, 19 towards the outlet orifice 25.

(18) The injection device 10 depicted in FIG. 1 is commonly referred to as being of the impact type.

(19) Here, the first zone Z1 and the second zone Z2 take the form of a straight internal pipe connecting the first inlet opening 15 the outlet orifice 25 in an axial direction of the said body. This internal pipe in this embodiment has a constant internal diameter. The invention is not, however, limited by this embodiment. The internal cross-section of this pipe (in other words of the body) could vary continuously or be constant over the entire length of the pipe (i.e. of the body), without, however, being circular.

(20) In the embodiment depicted, the body 12 is a cylinder, in other words the internal wall 13 here is cylindrical, its axis coinciding with the longitudinal direction X of the body.

(21) The liquid emanating from the introducing element 16 is sprayed against the impact surface 22 of the target 21 as soon as it enters the first zone Z1. The jet of liquid is broken open and carried in the form of droplets by a stream of atomizing gas introduced at high speed by the gas introducing element 14. Atomization of the liquid takes place in two stages. A first part of the atomization occurs at the target 21 as the jet of liquid impinges on the impact surface 22 of the target 21. The jet of liquid thus broken open undergoes shearing by the gas entering via the pipe 20 and by the gas introduced by the first gas introducing element 14. The second part of the atomization occurs at the reduced-diameter outlet orifice 25, where the narrowing in diameter accelerates the fluids.

(22) According to the invention, the internal wall 13 of the body is also provided, between the first zone Z1 and the second zone Z2, with at least one chicane 26.sub.i (where i, the number of chicanes, is a non-zero whole number). Because this chicane locally reduces the diameter of the internal wall 13, it disrupts the movement of the fluid, encouraging mixing. In particular, the presence of a chicane makes it possible to avoid the formation of a film of liquid on the wall by bringing the liquid back into the axis of the stream of gas.

(23) One or more chicanes may be provided.

(24) The injection device 10 may thus comprise a single chicane 26.sub.1, depicted in FIG. 2a, situated at the line of section A-A in FIG. 1. This chicane 26.sub.1 takes the form of a solid ring extending over the entire periphery of the internal wall 13. Here, the chicane 26.sub.1 defines a wall extending at right angles to the longitudinal direction X.

(25) FIGS. 2 to 8 depict other embodiments which differ from those previously described in terms of the number and/or shape of the chicanes. In these figures, the chicanes are denoted by the reference 26 or 126, the suffix i, which is a non-zero whole number, representing the number of chicanes, the symbols prime (), double prime () and triple prime () denoting embodiments that differ from those previously described.

(26) FIGS. 2b and 2c are views in cross-section of chicanes according to another embodiment in which each chicane 26.sub.i is configured so that, in each plane perpendicular to the longitudinal direction X of the body containing this chicane, the chicane extends over just part of the periphery of the internal wall.

(27) In this example, four disjointed chicanes 26.sub.1, 26.sub.2, 26.sub.3, 26.sub.4 are provided.

(28) It will be noted here that each chicane 26.sub.1, 26.sub.2, 26.sub.3, 26.sub.4 is configured in such a way that the orthogonal projection of the chicane onto a plane perpendicular to the longitudinal direction of the body extends over just part of the periphery of the internal wall in the said plane of projection (see FIGS. 2b, 2c). In other words, the view of this plane of projection is similar to that in FIG. 2a.

(29) Two chicanes 26.sub.1, 26.sub.2 here extend in one and the same plane perpendicular to the longitudinal direction X, the other two chicanes 26.sub.3, 26.sub.4 extending in another perpendicular plane, spaced away from the plane of the chicanes in the longitudinal direction X (see FIG. 1). The invention is not restricted by this embodiment, one or more other chicanes being able to be in a distinct third plane perpendicular to the longitudinal direction X or in still other distinct planes. As an alternative or in combination, just one chicane could be provided at each specific position along the longitudinal direction X.

(30) The chicanes 26.sub.1, 26.sub.2, 26.sub.3, 26.sub.4 are furthermore offset angularly by rotation about the longitudinal direction X, as visible in FIGS. 2b and 2c. It will be noted that the chicanes are in a staggered configuration, their orthogonal projection onto a plane perpendicular to the longitudinal direction of the body extending over the entire periphery of the internal wall 13.

(31) As an alternative, provision could be made for the orthogonal projection of these chicanes 26.sub.i onto a plane perpendicular to the direction X not to extend over the entire periphery of the internal wall 13 but to extend over just part, as depicted in FIG. 2d.

(32) In another alternative form that has not been depicted, provision could be made for the orthogonal projection of the chicanes onto a plane perpendicular to the direction X to extend over the entire periphery of the internal wall 13, with the projections of the chicanes overlapping.

(33) Thus, the relative layout of the chicanes may be chosen in such a way as to cause as much disruption as possible to the movement of the fluid circulating inside the injection device, without increasing the drop in pressure.

(34) In the example depicted in FIG. 1, the chicanes take the form of planar walls perpendicular to the longitudinal direction X. In other words, one edge of the wall of each chicane is thus secured to the internal wall 13 along a line extending in a plane perpendicular to the longitudinal direction of the said body.

(35) The chicanes depicted in FIGS. 1 and 2a-2d define planar walls perpendicular to the longitudinal direction X. These walls could also be curved. Thus, FIG. 3 is a partial depiction in axial section of the injection device 10 provided with chicanes 26.sub.1, 26.sub.2 that are curved, notably in the direction of the central longitudinal axis of the body 12. Here, the concavity of these chicanes is orientated towards the outlet orifice 25. Nevertheless, provision could be made for it to be orientated in the opposite direction.

(36) In this embodiment, each chicane 26.sub.1, 26.sub.2 defines a wall, one edge of which is secured to the internal wall 13 along a line extending in a plane perpendicular to the longitudinal direction X. Although not depicted, other chicanes 26.sub.i spaced apart in the X-direction and/or angularly offset from one another could be provided.

(37) FIG. 4 is a partial perspective depiction of the wall 13 of an injection device 10 comprising a chicane 26.sub.1 which defines a wall, one edge of which is secured to the internal wall 13 along a segment of a helicoidal curve H. The chicane 26.sub.1 may define a planar or curved wall, as depicted in FIG. 3.

(38) One or more chicanes 26.sub.i may be provided, these for example being angularly offset and/or spaced apart in the longitudinal direction X. furthermore, they may be arranged relative to one another in such a way as to impart to the fluid impinging on the curved face thereof one and the same rotational movement about an axis parallel to the longitudinal direction of the body.

(39) The chicanes described hereinabove may be produced as one piece with the body 12, for example by moulding or machining, or may be added-on elements which are fixed, for example welded, held between flanges, or the like. When several chicanes are present, they may be identical or different, it being possible to combine the various shapes and arrangements of chicanes described hereinabove.

(40) The chicane or chicanes are arranged between the first and second zones Z1, Z2. Typically, the second zone has a length (in the longitudinal direction X) 2 to 10 times greater than the length of the first zone. The chicane or chicanes, notably the first chicane, may be situated at a distance 1 from the axis of the target 20 or of the openings 17, 19 that is less than the diameter of the internal wall 13, at the level of the first zone, for example at a distance corresponding to of this diameter (for the sake of clarity, the figures are not drawn to scale).

(41) The chicane or chicanes may have a radial dimension or height (perpendicular to the longitudinal direction X) that is relatively small, for example less than .sup.th of the diameter of the internal wall 13, or even of the order of 1/10.sup.th of this diameter. This height may be variable along the length of a chicane, as depicted in FIG. 5, in which four chicanes 126.sub.1, 126.sub.2, 126.sub.3, 126.sub.4 are depicted, with their height varying at the ends.

(42) The non-zero thickness of each chicane, measured in the longitudinal direction X of the body is, for example, at most 16 to 35 mm.

(43) It will be noted that, whatever its shape (curved or planar), a chicane (or the tangent thereto at the point at which it meets the internal wall 13 of the body) may define a predetermined angle with respect to a plane orthogonal to the longitudinal direction of the body (see FIGS. 3, 6, 7(b) and 8(a)). This angle may be variable for one and the same chicane 126, as visible in FIG. 6.

(44) The chicane or chicanes inclined in this way may be inclined in the direction of the outlet orifice 25.

(45) Whatever its shape (curved or planar), the free edge of a chicane (the opposite edge to the edge secured to the internal wall of the body) may have a face 28a of rounded shape (FIG. 7(a)), a face 28a that is bevelled (FIG. 7(b)), two faces 28a, 28b with a rounded shape (FIG. 8a)) or two faces 28a, 28b with a bevelled shape (FIG. 8(b)).

(46) When just one face is provided, it is preferably situated on the side of the mixing zone Z1 in the longitudinal direction X.

(47) The various embodiments described hereinabove may be combined and implemented with equal preference for one or more chicanes.