GB2051606A - A fluid distributor device for exchange columns - Google Patents

Abstract

The device consists of a glass main distributor element supplying fluid to be distributed to a number of transversely extending gutter channels (2). Each channel (2) has a series of pairs of opposed outflow ports (3) in the side walls thereof. The ends of a drip elements, eg metal wire loops (4), are engaged in the respective ports (3) of each pair, so that fluid flowing through the ports (3) of each pair forms a single vertical stream. A good distribution can be obtained with this construction even at small fluid loads. <IMAGE>

Description

SPECIFICATION Fluid distributor device for exchange columns The present invention relates to a fluid distributor device for installation in exchange columns or towers.

Distributor devices are required to split a single coherent stream of fluid into the maximum possible number of parts in such a way that the fluid load (units m3/m2/sec) is applied evently over the cross sectional area of the column to be treated or at least that the variations in load distribution remain within tolerable limits. At the same time, the distributor devices must be so designed that they do not unduly obstruct the rising current of steam, vapour or gas.

In the past there were basically three methods, or principles, of operation whereby a fluid distribution in the above-defined sense could be achieved.

1.1 Atomization by means of atomizer jet This method can provide satisfactory results only on condition that a certain initial feed pressure (about 1 bar) is available.

Example: jet nozzle 1.2 Overflow from a weir-box The fluid stream is fed to a cup or dish shaped weir box, or to a trickle channel system, provided with a plurality of notches or incisions of any desired form or shape along the edges of their lateral walls through which the fluid spills out.

Example: spout distributor.

1.3 Outflow from a hole The stream of fluid is fed to a dish, trickle channel or pipe system, all provided with a series of holes in an underside thereof through which the fluid is discharged by hydrostatic pressure.

Example: Distributor pipes, Ring-spray, or shower-head These known systems have serious drawbacks: ad 1. 1 This kind of system cannot be fitted with natural feed in a column (e.g.

for redistribution).

ad 1.2 The disadvantage of a weir box over spill system is that a satisfactory de gree of accuracy (a branch stream volume deviation from the mean of about 30%) is achievable only with large stream volumes and there is a fundamental inherent accuracy limit.

For example, for a rectangular, or triangular notch, the following relations apply: v'--'hvh = h' 5 h = overspill height or V~h2A/h = h2.5 V = stream volume Thus, a variation of overspill height h by i 20% will mean variations in the branch stream volume which in the first case amount to about 30% and in the second to about 50%.

The problem of maintaining the branch stream volumes constant is further aggravated by the fact that absolute overspill heights are mostly very small (2 to 6 mm) and for this reason even an acceptable variation of V = 30% demands high precision standards in the installation of the distributor system.

Conventional distributor trays operate on the weir-box overspill principle. Owing to the high precision standards required they are very expensive.

If the distributor tray consists of a tray with spouts, the available cross-section for steam is no greater than 50%. It will be even smaller if the fluid charge is required to be evenly applied over the entire cross-section of the column right up to the periphery.

ad 1.3 This principle, whilst being consider ably more accurate (V~h05) and be ing also suitable for smaller amounts of fluid, has other vital disadvan tages: Small outflow ports of the type required for small amounts of fluid tend to become quickly blocked if the fluid medium is polluted with dirt.

The uniformity of the branch stream volumes, e.g. with a pipe distributor system, is by no means optimal because, depending on local flow velocity, hydrostatic pressure varies from port to port (Bernoulli's energy equation).

Example: Distributor pipes.

If, on the other hand, larger pipe sections are chosen in order to obtain lower flow velocities and thus smaller hydrostatic pressure differentials at the individual outflow ports, this increases still further the risk of dirt accretion and blockage because of the low flow velocity.

There are also liquid distributors which consist of a dished weir box and small spouts from which the fluid flows out separately from the steam or vapour flow and separate, larger spouts are provided for the latter. These distributors, as mentioned under 1.2, leave a cross-section available for steam of only less than 50%.

It is the aim of the present invention to avoid the disadvantage appertaining to existing distributor systems and to provide a distributor device which distributes the fluid in optimally even fashion over the contact reaction area of the exchange column and which has the following advantages.

-smallest fluid loads, i.e. effective operation even at the lowest hydrostatic pressures.

-distribution of the fluid right up to the periphery of the packing (necessary for systematic column packings).

-large cross-section available for steam -insensitivity to positional deviations.

-insensitivity to dirt.

-wider operation range.

IV max\ V min -inexpensive manufacture.

-potential for low cost adaptation to most frequently encountered types of application and requirements.

According to the present invention, there is provided a fluid distributor device for installation in an exchange column, comprising a horizontal main distributor element, gutter channels extending transversely relative to said element and being with outflow ports for fluid to be distributed, wherein (a) the main distributor element and the gut ter channels are made of glass; (b) the said main distributor element is a pipe; (c) the gutter channels are fitted on said pipe; (d) the said outflow ports are arranged in opposed pairs on the side walls of said gutter channels; and (e) in said outflow ports, drip elements are suspended in such a way that the fluid from each pair of ports forms a single vertical stream.

In the accompanying drawings: Figure 1 is a side elevation of one embodiment of distributor device according to the present invention; Figure 2 is a plan view of the device of Fig.

1; and Figure 3 is a vertical section through a gutter channel forming part of the device of Figs. 1 and 2.

The distributor device consists of a plurality of parallel gutter channels (2) which are mutually connected on their undersides by a transverse pipe (1) so that the fluid levels in the individual channels (2) are equal (the principle of communicating tubes). The pipe (1) and gutters (2) are made of glass.

The stream of fluid which is to be distributed is fed into this transverse pipe (1) at any desired point thereof. At arbitrarily selected, spaced intervals the side walls of the gutter channels (2) are provided with opposed ports (3) all of which are spaced equidistantly from the top edge of the channel. In this embodiment, the distributor device is made in such a way that the top edges of all of the channels (2) and thus also all outflow ports (3) are at the same height. A metal wire loop (4) is engaged in each pair of opposed outflow ports with the result that (a) the outflow cross-section is reduced, and (b) the two outflow streams from each pair of opposed ports are combined, because of the surface tension of the fluid, and thus drip, or trickle off the wire below the channel.

Each wire loop (4) has hook-like ends which are respectively engaged in the ports (3) of each pair. Each wire loop (4) is twisted intermediate its ends, the twisted portion lying below the channel (2) and being directed vertically downwardly.

With large amounts of fluid, on the other hand, the fluid emerges in two distinct streams or jets (sprays) and this improves spraying uniformity or even distribution (the area per branch stream volume is halved).

By selection of appropriate outflow and channel height dimensions, the distributor device can be readily adapted to any desired working range. The spread, or range of the distributor may also be increased by a vertically staggered arrangement of the outflow ports so that they are successively functional.

The underside of the transverse pipe (1) is provided with a number of outwardly flanged holes (5) through which any frictional detritus of the column packing can be washed out (e.g. when operated for redistribution or recycling).

The number of gutter channels and of outflow ports is optional. The dimensions of the channels and their relative distances may be suited to local requirements.

The drip elements are preferably made of a chemically resistant material. In an alternative embodiment, the drip elements are made of a narrow metal strip. In a further modification, the outflow ports are arranged at different levels.

Claims (6)

1. A fluid distributor device for installation in an exchange column, comprising a horizontal main distributor element, gutter channels extending transversely relative to said element and being provided with outflow ports for fluid to be distributed, wherein (a) the main distributor element and the gut ter channels are made of glass; (b) the said main distributor element is a pipe; (c) the gutter channels are fitted on said pipe; (d) the said outflow ports are arranged in opposed pairs on the side walls of said gutter channels; and (e) in said outflow ports, drip elements are suspended in such a way that the fluid from each pair of ports forms a single vertical stream.

2. A distributor device according to claim 1, wherein each drip element is a twisted wire loop having two hook-like free ends which are engaged in the respective outflow ports of each pair.

3. A distributor device according to claim 2, wherein each wire loop is made of metal.

4. A distributor device according to claim 1, wherein each drip element is a narrow metal strip.

5. A distributor device according to any of claims 1 to 4, wherein the outflow ports are arranged at different levels.

6. A distributor device substantially as hereinbefore described with reference to the accompanying drawings.