DE1442444A1 - Method and device for separating immiscible or difficultly miscible liquids - Google Patents

Description

METALLGESELLSCHAFT Frankfurt (Main), July 25, 1968

Aktiengesellschaft DrWer / GM

P 14 42 444. 3 Ί 442444

Method and device for separating immiscible or difficult-to-mix liquids.

In chemical engineering, the problem often arises of a liquid two-or-one To separate multiphase mixture into the pure phases. This applies above all to extraction processes, but also to other processes, such as steam distillation or synthesis, in which a two- or multi-phase mixture occurs as an intermediate or end product.

There are various methods for separating immiscible liquids and devices are known which are all based on the phase separation in a natural or artificial gravity field. For the separation of emulsions in particular Devices are known from "water in oil" emulsions which pack large-surface substances with one of the emulsions to be separated Contain adapted pore size and a subsequent empty separation space. In the pack of large-surface fabrics known as "Coalescer" the emulsion is first broken, creating a separable phase mixture. This mixture is then separated in the subsequent one as a "separator" designated empty separation space. A certain residence time is required in each case for sufficient phase separation require you, above all from the importance of the phases, theirs Viscosity, the droplet size and the interfacial tension depends. For a given liquid mixture is therefore at a given temperature and given gravitational field, the minimum required residence time is primarily determined by the desired sharpness of the phase separation. To the The dwell time is as short as possible and thus the throughput is kept high

(Art. 7 S1 Abe. 2 No. 1 Clause 3 of Amendment 38. ϋ. 4. 9, 18

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can, efforts are generally made to construct the separating apparatus in such a way that that the requirements for the sharpness of the phase separation can be kept as low as possible, i.e. the formation of a middle layer, in which the two phases are mixed - to allow as long as there is the possibility of the pure heavy and the pure light phase above or to be able to deduct below this middle class. Such a well-known one Apparatus is shown schematically and for example in Fig. 1. Fig. La is a horizontal cross-section along line A-A of Fig. Ib and Fig. 1c and Fig. 1b is a vertical cross section taken along line B-B of Fig. la, Fig. 1c is a vertical cross section taken along line C-C of Figures 1 a and 1 b.

The liquid mixture to be separated is fed to the separator 1 via the nozzle 2 and flows through it in the direction of the arrows. In the process, the light and heavy phase are either creaming or discontinued along the phase interfaces 4 and 5 shown in dashed lines. Above the interface 4 is only the pure light and below the interface 5 only the pure heavy phase is present. The pure phases enter the exhaust chamber 7 above and below the partition plate 6, from which they are withdrawn via the acceptance stubs 8 and 9. The effectiveness this device is of course only given if the phase interface 4 is below the upper edge and phase interface remains above the lower edge of the partition 6. But this is only guaranteed if the apparatus is not charged with too much phase mixture. Its maximum throughput is therefore limited by the speed with which the phases separate so far that the thickness of the middle layer does not exceed a predetermined value.

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To improve the phase separation and thus the throughput to increase, it is already known to place separating plates in the separating space to be incorporated, as shown e.g. in Figures Ha and Hg, the mainly to serve to reduce the drop height of the drops. This can actually do some improvement in the phase separation can be achieved, but the increase in throughput that can be achieved with it remains within relatively modest limits. This is especially true if the separator is to be as flat as possible, as is the case, for example, for column-like Multi-stage mixers and separators built on top of each other are desirable.

The present invention now shows a way, the phase separation still to improve much further and to enable an increase in throughput of more than 100% even in very flat separators. The invention is based on the surprising realization that one is far, stronger Improvement of the separation effect than by reducing the height of the fall is possible, if it is possible to create the conditions for the rapid enlargement of the droplets. Since the drop size in the mixture to be separated is generally predetermined, either by the degree of dispersion in which the mixture is obtained, or because one If, before the phase separation, the aim was to achieve the smallest possible droplet size in order to improve the exchange of substances, this droplet enlargement must only take place in the Separator itself are effected. It has further been found that this droplet enlargement is thereby achieved in a very simple and reliable manner it can be that the mixture to be separated is as sharp as possible Edges and tips is passed. In this case, however, according to the invention, further consideration must be given to the fact that between the sharp-edged Bodies still have a sufficiently free cross-section for the liquid to pass through.

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This is achieved according to the invention in that the separation space 3 with a filling of sharp-edged bodies is provided, their dimension at least in one direction, their dimension in the other directions at least 3 times, preferably a multiple of this amount exceeds. According to the invention, the filling is such that on 1

2 "■

cm of a surface at least 1 cm and a maximum of 100 cm sharp edges

omitted. The area of 10-25 cm per cm of surface is preferred

and in particular the area 15-20 cm per cm because within these areas the beneficial effects of the sharp edges are already very extensive can be achieved, so that a substantial excess of the ratio brings no significant improvement in the separation effect, on the other hand is a filling with a particularly high. Ratio of,

not so easy to produce sharp edges to the surface ^ especially if a significant Vermindejrung the free cross-section of the separation is to be avoided, "The simplest embodiment-of the invention is to fill the separation area 3 with sharp-edged metal wool _s metal turnings or the like. It is particularly advantageous to use fabrics made from sharp-edged tapes about 0.5-2 mm wide, such as those used for cleaning metal objects. '.. "-.

The filling of the separating space with the same amount of round wires or woven fabrics made from them, does not produce the same distinctive effect by far . The separation effect achieved with a filling of round wires hardly differs from the one without; Achievable filling.

Another embodiment of the invention sees the use in a relative manner narrow metal strips in front, which are also preferably arranged in this way can be that they simultaneously reduce in a known manner

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cause the height of fall, such. B. in Fig. III a <- c shown.

For this embodiment of the invention, the strips must be so narrow be that their width does not exceed 2 cm and preferably 1 cm

2 in the required area of at least 1 cm sharp edge per cm Surface to come.

The invention is explained below using an exemplary embodiment.

Embodiment 1;

The separation test was carried out in the apparatus shown in Fig. 1. The separator would have an internal diameter of 800 mm 300 mm high and the partition was at a distance of a = 120 mm from Extraction nozzle removed, attached. A mixture was used as the test mixture of 10% by volume of technical pentane. 40 vol.% Coke oven benzene with a Aromatic content of 90% and 50% by volume extraction agent used, the " consisted of N-methyl-pyrrolidone with a water content of 17% .. In this mixture, the interfacial tension is 0.1 dyn / cm, the Density difference 0.113 g / ml, the two phases were in volume ratio from 55 parts of extraction agent (heavy phase) to 45 parts of hydrocarbon mixtures (light phase) applied. A height of 250 mm was set as the permissible mixed layer height, since the height of the separating plate was 260 mm. ·.

Without filling, this mixed layer height could be up to a surface load (total throughput in cbm / h based on the area of the separator in sqm) of 9.4 cbm / sqm. h to be maintained. For fixtures In the separating space, according to FIG. 2, this load could increase to 12.2 cbm / sqm.h

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be increased what. corresponded to a load increase of 30%. These fixtures were replaced by a filling of metal turnings, which were on average 50 mm long and 3 mm wide and partly spiral Had form; there was an increase in the load to 20.8 ebm / qm.h possible without exceeding the permissible mixed layer height. Became Instead of the metal turnings, a filling of commercially available pot cleaners, i.e. loose fabric made of sharp-edged metal strips with a width of 1 - 2 mm used, the load could increase to 22 cbm / qm.h. can be increased.

Claims

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Claims (3)

PATENT CLAIMS 1.) A method for breaking down liquid multiphase mixture into the pure phases in a natural or artificial gravity field within a separation space provided with xiJinbauten, into which the multiphase mixture is introduced and from which the separated pure phases are derived, characterized in that the internals are made of known large-area bodies exist that do not significantly reduce the free cross-section of the separation space, and whose dimension in one direction is at least three times as large as in the other directions, and
10 to 25 cm sharp edges. 2 is, as in the other directions, and per cm of surface 2.) phase separator for carrying out the method according to claim 1, consisting of a separation space (3) with a feed line \ 2) for the multiphase mixture and through the discharge chamber (7) with the discharge lines (8), ( 9) 'for the pure phases, characterized in that the phase separator consists of a flat cylindrical housing, the height of which is smaller than the diameter of the base, that the partition (6) lies on a chord of the cross-sectional circle and between its edges and the circular walls of the cylindrical housing allows passages for the separated phases to the fume cupboard from the separation space, and that the separation space with per se known sharp-edged bodies, the dirnesnion of which is at least three times as large in one direction as in the other and each cm '
Have edges, is filled. 3
as in the others and the 10 to 25 cm sharp per cm surface 3.) Device according to claim 2, characterized in that the sharp-edged bodies are metal turnings. Documents v * tf & ι * & ·. 2 νγ. ι set 3 dw change «and» a3e. «. 4. ». in · .80 98 13/0 4 13 '