DE1029342B - Filler for fractionating columns - Google Patents

Description

GERMAN

It is known in fractionation columns and similar devices for contact between a liquid phase and a vapor phase to apply packing. Most of the time these packing elements are complicated designed with the intention of repeatedly mixing the falling liquid well and creating one to promote good contact between the liquid phase and the vapor phase (see e.g. the German patent specification 666 465, the Austrian patent specification 40 408 and. U.S. Patent 2,594,585). There the steam is constantly forced to change its direction, a pressure loss occurs, so that this packing cannot be used to fractionate heat-sensitive substances because a high Then vacuum cannot be maintained in the whole fractionating column.

There are from the German patent specification 209 826 and the British patent specification 622 706 packing known, which consist of plates which are arranged parallel to one another at approximately equal intervals are for use in a column in which a liquid phase and a vapor phase are in contact can be brought and in which the packing are arranged on top of one another that the plates in the are arranged substantially parallel to the axes of the column, not touching the walls of the column, which Plates any of the bodies not parallel to the Plates of the bodies directly above or below are and the upper edges of the Plates of one body are in direct contact with the lower edge of the next body. In Columns, filled with such packing, the flow direction of the steam is neither deflected still hindered, so that no great pressure loss occurs. According to British patent specification 622 706 The parallel plates can be made of metal wire mesh.

According to the invention is now with such packing z. B. in fractionation columns a much more than twice better separation of components with few different boiling points is achieved when the parallel plates of the packing are made of double metal wire mesh. However, they are from US Pat. No. 2,594,585 packing elements, ζ. Β. Cube, known, made of several layers of wire mesh existing, but these packings are designed in such a way that the steam rises as it rises is forced to pass the mesh. As a result, the pressure loss here is much greater than when the steam rises up along the chain-link plates.

The better results with plates made of double metal wire mesh are a consequence of the better ones Wettability. This distributes the down-packing for the fractionating column !!

Applicant:

N. V. Polak & Schwarz's Essencefabrieken, Hilversum (Netherlands)

Representative: Dr. H. Wittek, patent attorney,
Heidelberg-Schlierbach, Im Grund 20

Claimed priority:
Netherlands December 15, 1953

Rolfe Alexander Stennett Lacey, London,
has been named as the inventor

trickling liquid immediately from the contact points of the plates of two stacked packings also in the horizontal direction. Therefore it is not necessary to put the liquid in the top Column is fed, e.g. B. the reflux in a fractionating column, or the washing liquid in one Distribute the gas washer exactly over all the plates of the top packing, because even if the liquid If only one plate of the uppermost packing is fed, all plates of the second are immediately or third packing completely moistened. In contrast, when using simple metal wire mesh it is very difficult to moisten the plates well.

To explain the claim, the following should be stated: Under the expression »essentially parallel «is to be understood to include small deviations of up to 10 ° from the parallel direction will.

The height of each packing is preferably less than the equivalent height of a theoretical one Bottom of the filled column. This term, which is well known in distilling technology, (see e.g. Badger and Mc.Cabe: "Elements of Chemical Engineering Technology", Berlin 1932, pp. 272 and 257), is a measure of the separation capacity of a fractionating column. The smaller the equivalent height of a theoretical soil, the better the separability of the column. The equivalent height of a theoretical bottom of a fractionating column, filled with packing according to the invention, is still further

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decreased when the lower corners of the panels are beveled.

To prevent liquid from trickling down the walls of the column, be Packing preferably that with a collecting device are provided which are in direct contact with both the walls of the column and with the plates of the packing. The collecting device can, for. B. consist of a conical ring that so · um the body is arranged so that it touches the plates of the body with its inner and lower edge. The best results are achieved when the plates and also the conical ring are made of double Steel wire netting is made up of which the wires are at an angle of about 45 ° to the top edge of the Plates of the packing or of the ring run.

The invention also relates to columns which are internally provided with a series of packing elements according to FIG Invention are provided that have been set apart at an angle of up to 90 °.

The invention will be explained with the aid of the drawings.

Fig. 1 is a longitudinal section through a column filled with packing according to the invention;

Fig. 2 is a view of a packing used in the column of Fig. 1;

Fig. 3 is a plan view of such a packing;

Fig. 4 is a longitudinal section through such a packing.

In the column 6 of Fig. 1, packing 1, one above the other, are used, in fact in one such that the plates of a filler body at right angles to the, plates of the above or the filler located underneath. From Figs. 2 and 3 it can be seen that in each packing the plates sit on a rod 4 and are held at equal intervals by spacer rings 5. At the tip of the filling body is a conical ring 3 is provided with its inner and lower circumference touches the plates. This ring serves both as a collector and as a redistributor of every liquid, which herabrinait on the walls of the column over the parallel plates. In Fig. 4 is the direction of the Wires of the wire mesh used indicated.

In the following, the separation capacity of a column filled with the above-described packing elements, the plates consisting of simple steel wire mesh, is compared with the pumping capacity of the same column with such guide elements with plates made of double steel wire mesh. Steel wire mesh with 24 meshes per cm ^{2 was used} . For the production of double wire netting, simple steel wire netting was used in such a. Cut into strips of about 5 cm so that the wires formed an angle of about 45 ° with the edges of the strips. Two such strips were connected to one another by means of electrical welding along lines parallel to the edge of the plate. To make the packing, 14 plates of single or double wire mesh were combined into a circular unit, 5 cm high and 10 cm in diameter, with a plate gap of about 0.62 cm. Such a unit was then equipped with a conical ring as shown in Figs. 1, 2, 3 and 4. A column 10 cm in diameter and 152 cm in height was filled with sensors made of simple wire mesh and another column of this type with sensors made of double wire mesh. A mixture of ct-jonon (w | ° = 1.4982) and / 2-jonon (nf = 1.5205) was then distilled in both columns under a pressure of 3 mm of mercury. It was found that the column with the sensors made of double wire mesh has a separation capacity corresponding to 12 theoretical plates (see Badger and Mc. Cabe: "Elements of Chemistry Engineers Technology", Berlin 1932, p. 257) and that Column with the packing made of simple wire mesh, however, a separation capacity corresponding to only three theoretical plates. It is clear from this that the use of double wire netting increases the separating capacity of the column much more than could be expected on the basis of the doubling of the wire netting. With columns of larger diameter, the effect of double wire mesh is even greater. In the above example, 22 kg of liquid was converted into vapor every hour. It was also found that when much higher evaporation rates are used, the separating capacity of the column with packing made of double wire mesh does not decrease, while the pressure drop in the column also remains low. The separating capacity of a column with sensors made of simple wire mesh, on the other hand, decreases rapidly with the use of higher evaporation speeds, while the pressure loss also increases sharply, since the liquid trickling down occurs due to the lower wettability of the simple wire mesh with high vapor speeds. Due to the high pressure losses, it is therefore not possible to fractionate mixtures of heat-sensitive substances with high evaporation rates in columns with random packings made of simple metal wire mesh. In contrast to this, this is quite possible in columns with sensors made of double wire mesh.

Claims (5)

Patent claims: 1. Packing, consisting of plates of metal wire mesh, which are arranged parallel to one another at approximately the same intervals, for use in a column in which a liquid phase and a vapor phase are brought into contact can be and in which the packing are arranged on top of one another that the plates in the are arranged essentially parallel to the axes of the column, the walls of the column are not touch, the plates of any of the bodies are not parallel to the plates of the immediate above or below body and the upper edges of the plates of a body in are in direct contact with the lower edge of the next body, characterized by that the plates are made of double metal wire mesh. 2. Filling body according to claim 1, characterized in that each filling body with a collecting device (3) which is in direct contact with both the walls of the column and the plates of the body. 3. Filler body according to claim 2, characterized in that the collecting device (3) consists of consists of a conical ring which is arranged around the body that it with its inner and the lower edge touches the plates (2) of the body. 4. Packing body according to claim 1 to 3, characterized in that both the plates (2) as also the conical ring (3) consist of double steel wire mesh, in which the wires the double metal mesh at an angle of about 45 ° to the upper edge of the panels (2) the filler or the ring (3) run. 5. Filler body according to claim 1 to 4, characterized in that the lower corners of the plates (2) are beveled. Considered publications: German Patent Specifications Nos. 209 826, 666 465; Austrian Patent No. 40408; British Patent Nos. 426 560, 547 870. 622 706; U.S. Patent No. 2,594,585. 1 sheet of drawings © 809 509/377 4.58