Liquid dispenser

Abstract

A gravity liquid distributor (1) comprises: a lower plate (P) provided with orifices through which a liquid leaves the distributor to irrigate a lower element, parallel parallelepiped chimneys (C) dedicated to the passage of the ascending gas, thus delimiting liquid chutes above the lower plate, these chimneys being provided with closure means on the upper part allowing both to deflect the liquid, the chimneys are distributed over an entire central part with a circular section of the lower plate, releasing a peripheral channel on the perimeter of the lower plate fluidly connected to the chutes, a plurality of plates (R1, R2) capable of guiding the liquid collected above the chutes towards the peripheral channel, each plate having an elongated rectangular shape with two ends, with a single plate per chute,the platelet being sealed at one end only such that at least the majority of the collected fluid flows to the peripheral channel, the platelets are oriented at an acute or zero angle to the horizontal. Abstract Figure: Figure 4,

Description

Title of the invention: Liquid dispenser

[0001] The present invention relates to the field of fluid contacting equipment. Gas / liquid contacting columns or towers sometimes use packings to improve heat and mass exchanges between a liquid and a gas. These columns are commonly used for heat transfer, distillation, absorption or stripping applications. When packings are used, distributors are also used whose main function is to distribute the liquid uniformly over the packing in order to make the best use of the contact surface developed by the packing as a support for the liquid, while allowing the gas to pass through gas passages, also called chimneys. Gravity distributors are by far the most used.

[0002] Distributors are therefore used at the liquid inlets but they are also used after a certain section height from which the distribution is no longer considered sufficiently uniform to satisfy a good level of exchange. The liquid is then collected using equipment called a collector which then feeds a distributor. When the collector and the distributor are integrated to gain height, the equipment is called a redistributor.

[0003] A redistributor allows the liquid flow rates to be redistributed evenly. However, they also allow, to a certain extent, the composition and temperature of the liquid to be horizontally homogenized. This function is sometimes crucial for the column to operate correctly. This is particularly the case for difficult distillations where the components have very similar boiling points, or when very high purities are required on one side or the other of the distillation section. In these situations, poor composition distribution has a significant impact on the column's performance.

[0004] It is generally not necessary to mix all the liquid in the column at one point. By mixing only a fraction of the liquid, almost complete correction can be achieved. The difficulty lies in mixing over long horizontal distances and ideally in both directions of the plane in a reduced height.

[0005] In addition, we seek to limit the horizontal speeds at the level of the perforations of the distributors. Indeed, horizontal speeds that are too high are likely to generate flow disparities in each perforation.

[0006] State of the art

[0007] There are devices to promote the mixing of the liquid and therefore its horizontal homogenization. In general, a separate collector and distributor are better suited to mixing. In fact, in the case of a collector, we generally conduct the entire liquid flow in a pipe or a small number of pipes. However, columns sensitive to maldistribution are often those which require a lot of exchange surface and where vertical compactness becomes an important issue.

[0008] To ensure uniform flow rates, the same hydrostatic height must be present above each perforation. For this, the most robust solution is to have hydraulic continuity of the liquid guard, via a channel that connects the different distribution zones. This channel generally crosses the center of the distributor or occupies its periphery over its entire circumference.

[0009] To promote homogenization of the composition compared to standard redistributors, ramp and baffle systems are sometimes designed to mix the liquid in the redistributors.

[0010] In the case of a distributor with chimneys of rectangular section, mixing in the main direction of the chimneys is easier to promote than in the transverse direction. It is sometimes customary to alternate the orientation of the distributors to mix in the two directions of the plane for two successive lined sections. However, this usage introduces an architectural design constraint, particularly for gas or liquid inlets and outlets.

[0011] Redistributors with a mixing function are sometimes made with an outer crown to collect the liquid that has accumulated on the wall and plates that conduct a fraction of the liquid towards the center.

[0012] More recently, a mixing redistributor has been designed so that a fraction of the liquid collected on each side of a column is conducted to the other end of the column in the direction transverse to the chimneys. Such a device makes it possible to homogenize the composition in a compact redistributor. However, it cannot directly support the packings of the upper section. Additional crosspieces must be added to it. In addition, it is more complex to design with numerous overflows to be sized and an upper peripheral channel of complex shape.

[0013] OBJECT OF THE INVENTION

[0014] The invention described in these lines aims at a simple device for distributing the liquid reflux from a section of gas-liquid contact column with good homogeneity of flow rates, and a mixture of the composition improved compared to the state of the art without impact on the size.

[0015] Description and advantages of the invention

[0016] Compared to a simple redistributor with a rough homogenization as described in Jafari, S. et al. (2017). “CFD study of mixing performance of redistribution Systems for packed columns”, plates allow mixing of the composition in the direction of the chutes and the fact of closing one end of the plate to encourage the flow of liquid from the other end and possibly to direct them towards the peripheral channel by alternating the orientation or also promotes a mixture of the compositions on typically three chutes in the transverse direction, while maintaining compactness compared to solutions where the collector and the distributor are separated, and with a geometry that is simple to manufacture (number, complexity of parts and assemblies).

[0017] The distribution of the liquid over three chutes in the transverse direction is advantageous compared to a redistributor as described in US5752538 and US 5132055.

[0018] Furthermore, by design, the liquid flows at the bottom of the plates are less disrupted than those obtained at the necks formed by the baffles. Indeed, the liquid has only one main direction of flow and a larger overflow space including a portion of the peripheral channel and a part of the neck.

[0019] Although the transverse mixing is less than that described in US11426676, the distributor of the present invention is less complex and includes support for the lining sections without the addition of crosspieces.

[0020] Furthermore, the plates contribute to the structural rigidity of the distributor by further securing the gas chimneys.

[0021] According to an object of the invention, there is provided a gravity liquid distributor comprising: • a lower plate provided with orifices through which a liquid leaves the distributor to irrigate a lower element, such as a section of lower packing, • parallel parallelepiped chimneys dedicated to the passage of ascending gas, thus delimiting liquid chutes above the lower plate, these chimneys being provided with closure means on the upper part allowing both to deflect the liquid, for example descending from a section of packing above the distributor, and preferably to mechanically support this section, • the chimneys are distributed over an entire central part with a circular section of the lower plate, releasing a peripheral channel on the perimeter of the lower plate fluidly connected to the chutes, • a plurality of plates capable of guiding the liquid collected above the chutes towards the peripheral channel, each plate having an elongated rectangular shape with two ends, in which: • there is a single plate per chute, each plate being closed at one end only and possibly inclined so that at least the majority of the collected liquid flows towards the peripheral channel, • the plates are oriented at an acute or zero angle to the horizontal and • the closed end of the plates being alternated when passing from one chute to another.

[0022] According to other optional aspects: • at least one of the plates covers at most three quarters of the surface of the chute. • the distributor includes a jet breaker at the outlet of at least one plate and above the perforated plate to limit level disturbances caused by the fall of the liquid for low liquid heights. • some plates are located between two adjacent gas chimneys and have a length less than or equal to that of at least one of the two adjacent gas chimneys. • each plate has a flat bottom, the flat bottom being oriented at an angle between 0 and 30° to the surface of the plate, or even between 0° and 10° to the surface of the plate. • the plates are oriented at an acute angle to the horizontal and are alternately oriented towards one side or the other of the plate when passing from one chute to the next. • some or most of the pads are positioned so that the liquid exits the pads at one end of the two adjacent gas chimneys, in order to discharge the liquid directly into the peripheral channel. • each plate covers at least two thirds of the surface of the chute and possibly the entire surface of the chute.

[0023] According to the invention, a fluid contacting column is provided comprising at least one distributor as described above, means for discharging liquid above the distributor and a section of structured packing below the distributor.

[0024] The column may comprise a section of structured packings above the distributor supported by the sealing means.

[0025] Description of embodiments

[0026] The invention will be described in more detail with reference to the Figures.

[0027] [Fig.l] represents a redistributor 1 according to US 5645770 with plates R which also act as a means of closing off the gas chimneys C placed on a plate P. This solution is relatively simple but does not include the support function for the upper section. It also has low structural rigidity without the addition of parallelepiped chimneys which pass through the assembly.

[0028] [Fig.2] represents a redistributor 1 according to US11426676. The collection of a fraction of the liquid via the gas chimney sealing means and the segmented upper peripheral channel allows fine mixing of the liquid composition. On the other hand, it is quite complex and crosspieces must be added to the assembly (usually by welding) to support the upper section.

[0029] [Fig.3], [Fig.4] and [Fig.5] are top views of a dispenser according to the invention

[0030] [Fig.6] and [Fig.7] represent embodiments of the invention seen from the side.

[0031] [Fig.3] shows a gravity liquid distributor IA comprising: • a lower plate P provided with orifices through which the liquid leaves the distributor to irrigate a section of lower lining, • nine parallel parallelepiped chimneys C dedicated to the passage of the ascending gas, thus delimiting liquid chutes above the lower plate, these chimneys C being provided with closing means on the upper part allowing both to divert the descending liquid from a section of packing above the distributor and to mechanically support this section,

[0032] The chimneys C are distributed over the entire central part of the lower plate P, releasing a peripheral channel P on the perimeter of the lower plate, providing continuity to a plurality of plates R which guide the liquid collected above the gutters towards the peripheral channel P.

[0033] There is a single plate R per chute, the plate being inclined (as illustrated) and / or closed at only one end such that the majority of the collected liquid flows towards the peripheral channel.

[0034] The sealed ends alternate from one chute to another, so that if a plate in one chute has its left end sealed, the plates in the adjacent chutes will have their right end sealed and vice versa. Thus the plates discharge the liquid in a balanced manner onto the peripheral channel.

[0035] The plate may be horizontal or be at an acute angle of less than 30°C, or even 10°C to the horizontal, the plate P being oriented horizontally.

[0036] The plates RI, R2 are oriented in this example at an acute angle to the horizontal and are alternately oriented towards one side or the other of the plate when passing from one chute to the next. The plates RI, RI therefore have alternating slopes. Thus the four plates RI are oriented with their lowest end towards one edge of the plate and the five plates R2 are oriented with their lowest end towards the opposite edge.

[0037] A single plate RI, RI covers at most the entire surface of the chute but preferably only a fraction, for example at least two-thirds of the surface of the chute.

[0038] Optionally, jet breakers can be placed at the end where the liquid leaves the plates and above the perforated plate to limit disturbances to the level caused by the liquid falling for low liquid heights.

[0039] In the variant of [Fig.3] the plates have a shorter length than one adjacent chimney and longer than the other adjacent chimney, except for the central plate which has the same length as the two adjacent chimneys.

[0040] In the variant of [Fig.4], the three central plates are shorter than the adjacent chimneys.

[0041] The plates are preferably in contact with the vertical walls of the chimneys.

[0042] The dotted arrows in [Fig.5] describe the path of the liquid leaving the platelets and distributing via the peripheral channel into three connected troughs in [Fig.3].

[0043] In [Fig.6] we see that the upper end of each plate according to [Fig.4] is obstructed to prevent the liquid from pouring out the wrong way. The top of the chimney C is pierced with multiple openings to allow gas to pass through rising in the column.

[0044] In [Fig.7], we see from the side the version of [Fig.5].

Claims

Claims

1. A gravity liquid distributor (1) comprising: • a lower plate (P) provided with orifices through which a liquid leaves the distributor to irrigate a lower element, such as a lower packing section, • parallel parallelepipedal chimneys (C) dedicated to the passage of ascending gas, thus delimiting liquid chutes above the lower plate, these chimneys being provided with closure means on the upper part allowing both to deflect the liquid, for example descending from a packing section above the distributor, and preferably to mechanically support this section, • the chimneys are distributed over an entire central part with a circular section of the lower plate, releasing a peripheral channel on the perimeter of the lower plate fluidly connected to the chutes, • a plurality of plates (R, RI,R2) capable of guiding the liquid collected above the chutes towards the peripheral channel, each plate having an elongated rectangular shape with two ends, in which: • there is a single plate per chute, each plate being sealed at only one end and optionally inclined such that at least the majority of the collected liquid flows towards the peripheral channel, • the plates are oriented at an acute or zero angle to the horizontal and • the sealed end of the plates being alternated when passing from one chute to another.,

2. Dispenser according to claim 1 in which at least one of the plates (R, RI, R2) covers at most three quarters of the surface of the chute.

3. Dispenser according to claim 1 or 2 comprising a jet breaker at the outlet of at least one plate (R, RI, R2) and above the plate (P) perforated to limit level disturbances caused by falling liquid for low liquid heights.

4. Distributor according to one of claims 1 to 3 in which certain plates (R, RI, R2) are located between two adjacent gas chimneys (C) and have a length less than or equal to that of at least one of the two adjacent gas chimneys.

5. Dispenser according to one of claims 1 to 4 in which each plate (R, RI, R2) has a flat bottom, the flat bottom being oriented at an angle between 0 and 30° to the surface of the plate (P), or even between 0° and 10° to the surface of the plate.

6. A dispenser according to claim 5 wherein the plates (R, RI, R2) are oriented at an acute angle to the horizontal and are alternately oriented towards one side or the other of the plate (P) when passing from one chute to the next.

7. A dispenser according to any preceding claim wherein some or most of the plates are positioned so that liquid exits the plates at one end of the two adjacent gas chimneys, to discharge the liquid directly into the peripheral channel.

8. Dispenser according to one of the preceding claims in which each plate (R, RI, R2) covers at least two thirds of the surface of the chute and possibly the entire surface of the chute.

9. Fluid contacting column comprising at least one distributor (1) according to one of claims 1 to 8, means for discharging liquid above the distributor and a section of structured packing below the distributor.

10. Column according to claim 9 comprising a section of structured packings above the distributor (1) supported by the closure means.

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