DE1031280B - Device for distillation columns for the fractional separation of liquid mixtures - Google Patents

Description

Device for distillation columns for fractional separation of liquid mixtures The well-known continuous breakdown of liquid mixtures in a column in principle either allows separation into a pure top product and, depending on the circumstances, more or less contaminated sump mixture or, conversely, the isolation of a pure bottom product and an overhead mixture.

These variations are made possible by setting the return flow ratios accordingly, the absolute liquid removal overhead and the feeding of the column is achieved. The driving conditions also depend on the technical data of the convoy. Such Decompositions are possible for both binary and multiple systems, provided that no azeotropic disturbance occurs. In such cases, the azeotrope must be considered distillative to be viewed purely. In the case of multiple mixtures, as they often occur in practice, however, the aim is to be able to withdraw as many pure fractions as possible. Technically an approximation is achieved in that one in certain heights of the distillation column Makes taps, the quality of the withdrawn product in turn of several Factors such as the relative volatility of the individual distillation partners, the efficiency of the column and the loading and reflux ratios. A complete multiple separation in pure components is only through according to the current state of the distillation technology Combination of several columns possible. One adds, for example, a main column several side columns at. Under certain circumstances, a side column can be the size of the Reach or even exceed the main column. One pure component can be used per column subtracted from. One can therefore use one main column and four secondary columns obtained five pure products.

According to the invention it is possible to divide a liquid mixture into several to break down pure substances within a column. This is done through introduction one or more middle pieces (generally in the form of a tube) in one Column.

The essence of the invention is that the vapor flow of the liquid mixture by the conveniently arranged concentrically in the middle of the column, with the one end through a funnel-shaped extension on the inner wall of the column connected pipe in two flows running in opposite directions (fractions) is broken down, of which the distillate flowing in the outer ring channel with the lower Boiling point is withdrawn from the column.

Several such middle pieces (tubes) can be placed one above the other in a column be arranged.

In the drawing is an embodiment of the column according to the invention shown.

Fig. 1 shows part of a column with a tube in the middle is arranged concentrically, which at its upper end by a funnel-shaped Extension on attached to the inner wall of the column. Located above this attachment the feed line 1 for the liquid mixture to be distilled and below of the funnel, the outlet opening 6 for the distillate is attached. The volatile ones Components rise to the top; the higher-boiling parts fall through the pipe 2. At 3 is a division of the incoming steam mixture upwards, 4, and down, 5, possible. Through the tap opening 6, the can through the channel 4 ascending gases are deducted taking into account a sufficient reflux will. So it is so that at 3 a renewed fractionation in the lower boiling Share at the top and the higher-boiling mixture at the bottom. It is just now a question of the length of the built-in tube, whether the product withdrawn at 6 high concentrated or even pure. The nesting corresponds in its effectiveness an equally high side column, which also fulfills its purpose.

The effective path length increases, in terms of distillation, by the entire piece of stake. In other words, nesting is allowed a shortening of the column. So it becomes possible by introducing the nesting principle the separation of a multicomponent mixture into its pure components while maintaining it or even shortening the outer column dimensions and thus a reduction in size of the effective distillation volume.

By combining several tubular inserts (box sets), As FIG. 2 shows, the liquid to be distilled can be further broken down make so that a further pure component can be isolated per set. One Column with three box inserts permitted provided that the distillation conditions are correct the Decomposition into four pure components and a residual mixture.

The box column can be a packed column or a tray column (Bell bottom, sieve bottom, slotted bottom, cascade bottom, etc.) are carried out, whereby the packed column is best suited for laboratory purposes.

In general, nesting works best in descending order Branch. In this case, the opening is directed downwards. One more way However, there is also the nesting of the amplifier column, i.e. a division of the rising steam into several fractions. The mission then has its opening directed upwards, as shown in FIG. 3.

By adding together the individual components, a Arrangement are created, based on the feeding of the column, according to both Directions splitting of the steam streams into pure components enables (Fig. 4).

As already mentioned, the length and mutual spacing of the stakes must be be adapted to the distillative properties of the mixture used. These However, adaptation is also necessary with the known column shapes. The distillation The greater the reserve (separability and load), the easier it is. of the individual elements is. Accordingly, the components can also be different be long or can be extended by normal column sections. Furthermore can the inner and outer columns can also be chosen to have different widths. All of this is directed according to the desired, maximum requirements. The box column so can be made generous changes to suit any purpose.

The principle of nesting and the good separating effect it creates is not lost in the process.

The nesting can also have other designs adapted to the purpose take place without the separating effect being canceled. Instead of the individual A tube bundle can also be inserted into the inner tube. It is also possible directing the vapors as indicated in Figure 5, d. i.e., the vapors move down in the outer part and can be in the middle pillar section dismantled upwards and discharged.

The management of the steam flows or the condensation liquid withdrawn from each component can be done in different ways and thus a further increase in purity bring one or more products with them.

So it is z. B. possible, the withdrawn liquid on a component returned to the next higher level, as FIG. 6 shows. This is a particularly high purity of the product in question is achieved.

A nested column has a multiple column system with the same separating effect many advantages in terms of thermal housekeeping and technical work management.

Undoubtedly, the heat energy is because of the good and itself regulating heat exchange in a nested column better exploited. The circuit, Control and maintenance are much easier. That’s also a bigger one Operational safety given.

Next is an essential one with the application of the nesting principle Cheaper associated with the facility.

Both material and construction costs can, based on quantity and purity of the products are very discounted compared to the usual types. Furthermore is to consider an often not negligible saving of space and space.

The above advantages are demonstrated by the following example: In Fig. 7, a nested column is shown, which consists of eight components (S1 to S8). sl = column head, s2 = amplifier column of conventional design, length 900mm, s 36 mm, S3 = mixture supply, S4 = 1st component according to the box principle, length 900 mm, outside 36 mm, inside 18 mm, So = product acceptance, S6 = 2nd component as S4, S7 = Sampling, swamp.

At S3 a mixture of the following composition is introduced: volume percent Bp nD20 cyclohexane. . . . . . . . 30 81 "1.4264 toluene ........ ... 20 1100 1.4952 Is. Pr. CH. . . . . . . . . 30 152 ° 1.4412 decalin. . . . . . . . . . . 20 189 ° 1.4718 The column can now be operated in such a way that it can optionally be operated like a normal column works or the principle of nesting is applied. The decrease in the Products can be made at E1 to E6. The samples are taken from El, E3, E5. E6, then one applies the normal principle. Removing the products at E1, E2, E4 and E6, this is how you work according to the box pnnzip.

With a continuous addition of 200 ml per hour, the following products could be drawn off at the individual removal points after the distillative, continuous equilibrium had been established: Cyclohexane Toluene Iso-Pr. CH decalin E1 99.7 0.3 - E2 0.7 98.5 0.8 - It 1.0 55.0 30.0 14.0 E4 - 0.2 99.7 0.1 E5 - 0.5 50.0 49.0 Eat - - 5.0 95.0 In the decrease height corresponding to E2 + E2 and E4 + E5. It is therefore possible, with the help of two box elements, to break down the above-mentioned mixture into its three pure components and a highly concentrated bottom product, while normal operation does not allow this in the least.

PATENT CLAIMS: 1. Device for distillation columns for fractionated Separation of liquid mixtures, characterized by a column in which One or more appropriately tubular pieces (2) are arranged in the middle, at one end (3), open and at the other end expediently by a funnel-shaped Extension (7) are attached to the inner wall of the column, with a feed line (1) for the liquid mixture and tapping points (6) for the fractions.

Claims (1)

2. Apparatus according to claim 1, characterized by several one above the other arranged middle pieces (S2, S4, S6) '