DE2611454B2 - Abortion column - Google Patents

Description

The invention relates to a stripping column for liquids consisting of solutions or suspensions, in which during the mass transfer process Festobei the aborted

substances are precipitated

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Liquid is fed into the top part of the column and vapor into its bottom part, at which the column is in several stages through separating shelves arranged one above the other with drains for transport divided the liquid and the vapor space of a lower stage via at least one line for the Transport of the steam is connected to the level above it

Such columns, which lead to a distillative

ίο Separation of a liquid mixture using are used by steam, are known for example from DE-OS 20 37 237 and DE-OS 15 19 579

In contrast, the invention relates to a stripping column through which a three-phase mixture passes. You can z. B. be used for treating ammoniacal solutions or suspensions of metal salts, the treatment of which with steam, metal salts are precipitated. When driving off solutions or suspensions from which solids are precipitated during the mass transfer process, the case often occurs that the substance to be precipitated adheres to the column internals or distribution devices and leads to encrustations there, so that the column is clogged after a certain period of operation and can only be put back into operation after cleaning. Such incrustations of the precipitated substance mainly occur on the solid walls of the column:
a) in the reaction zone where the precipitation occurs;

b) if the walls of the column or the surfaces of the internals with steam and Alternately come into contact with liquid;

c) if the flow rate of the liquid on the walls of the column or the Soil is relatively low;

d) if the walls have temperatures which are higher than the boiling point of the solution.

The invention has set itself the goal of forming a stripping column in which such Incrustations are avoided.

This object is achieved according to the invention in that the line for the transport of the steam into a space delimited by side walls and open at the top and bottom, which opens into a space above A separating tray located bubble bed is arranged and that the drainage of each stage means for Has quantitative adjustment of the draining liquid.

The incrustations formed in the columns customary up to now are in accordance with the invention in one formed bubble bed column avoided that in the spaces bounded by the side walls, which are arranged within the bubble beds, a uniform upward movement of the liquid-vapor mixture arises, which causes a circulation of the liquid in the bubble bed. The resulting relatively high flow velocity prevents the formation of incrustations on the solid walls of the column and the dividing trays.

The spaces arranged in the bladder beds can e.g. B. be designed as tubes in which the Vapor is distributed in the liquid.

Static mixing elements can be installed in the tubes to improve the distribution of the vapor in the liquid to be ordered. For example, these can consist of perforated sheets arranged at intervals.

Another advantageous embodiment of this

static mixing elements can consist in that as

Internals for mixing processes already known static Mixing elements that are used there to produce stable mixtures are used (cf. z. B. CH-PS 5 37 208 and 5 47 120).

Since there is no steam in the liquid drains of the individual stages, this is the area at most an insignificant precipitation.

Furthermore, it can be advantageous to install the steam lines in the column, the drains and the dividing trays, which can be designed, for example, funnel-shaped, thermally isolate or with a To surround the cooling jacket, for example, in order to create encrustations even in places with low flow velocities to avoid.

The invention is explained below with reference to embodiments shown in the drawings.

F i g. 1 shows a schematic representation of a longitudinal section through a stripping column while in the

F i g. 2 to 4 exemplary embodiments for the individual stages of such a bubble bed column are shown.

The bubble bed column is denoted by 1 in FIG. 1. Separating columns 2 and 3 are connected to their upper and lower ends. In these Separation columns are packing 2a and 3a, z. B. Raschig rings or the like arranged Likewise can these separation columns z. B. be designed as bubble or sieve tray columns.

To column 2 - or if this column is not available, to column 1 - there is one Feed line 4 connected for the solution or suspension to be driven off, and a line 5 for the Vapor containing the components driven off from the solution or suspension.

The reference number 6 is that on the bottom part of the separating column 3 or, if this column is not is present, denotes the line for live steam connected to the bottom part of the bubble bed column 1, and a line 7 connected to the bottom of the column for the removal of the precipitated Liquid containing solids.

In the exemplary embodiment, the bubble bed column 1 has three stages 8 arranged one above the other Bubble beds 9, tubes 10 arranged in them, funnel-shaped separating floors 11 with drains 12 and valves 13 arranged therein. Instead of valves, the processes could also be used if necessary Have throttling points for the quantitative adjustment of the draining liquid.

From the steam space of a lower stage, a line 14 leads into each of the pipes 10 of the above arranged stage. If necessary, live steam can also be fed into the individual steam lines through lines 15 can also be initiated.

The steam lines 14 are advantageously laid outside the column. Maybe they could too be arranged within the column.

In the following, the mode of operation of the method shown in FIG illustrated embodiment of the invention explained using an exemplary embodiment.

The task is from an ammoniacal Ammonium carbonate solution and the metals dissolved in it (e.g. nickel, zinc or copper) to drive off ammonia and carbon dioxide with the help of steam.

For this purpose, the liquid is fed into the separating column 2 through the line 4. Herein is due to the exchange of material between the liquid and it counter-flowing vapor from the liquid leaving the bubble bed column 1 already forms part of the in The ammonia and carbon dioxide it contains are then separated off in the bubble bed column With the help of the vapor introduced into the individual stages from the liquid, the basic metal carbonates failed.

For the reasons described above, incrustations are caused by the precipitated Solids in the bubble bed column avoided, so that perfect operation of the column is guaranteed, and the suspension is free to flow down through the drains from stage to stage.

In the lower separating column 3, which is designed analogously to separating column 2, are of the Suspension due to mass transfer with the live steam fed in through line 6 is still in the suspension contained ammonia and carbon dioxide residues separated. Through the line 7 is the Suspension containing the precipitated solids, removed from the column.

In FIG. 2 shows an embodiment of a step 8 'which has a funnel-shaped separating base 11' having. A control valve 13 'is arranged in the outlet 12' of this separating base, which is controlled by a level controller 20 'is actuated so that the height of the bubble bed 9' is kept constant.

A line 21 'is connected to the steam line 14' through which, if necessary, an additional adjustable amount of live steam can be fed.

In the bubble bed 9 'a tube 10' is arranged, in which the introduced vapor is in the liquid distributed.

F i g. 3 shows a modified embodiment of a bubble bed stage 8 ″, with the same as in FIG Construction elements with the same reference numbers, which are only provided with the apostrophe " are, are designated. Notwithstanding FIG. 2 is in the tube 10 ″ from a spaced-apart perforated plates 22 existing static mixing element arranged. By arranging such a mixing element the distribution effect of the vapor in the liquid in the pipe compared to FIG. 2 significantly improved.

A metering valve 23 is fitted to the steam line 14 ″ before it enters the pipe 10 ″ Line 24 connected through the z. B. a small amount of water can be injected for cooling the steam line 14 ″ or for flushing away any incrustations that may have formed on the pipelines.

In addition, in this embodiment, both the steam line 14 ″, insofar as they are within the Column 1 "is relocated, as well as the Trenuboden 11" and the drain 12 "is surrounded by a layer of insulation material.

The steam line 14 "has a funnel-shaped design at its point of opening into the device 10" widening outlet opening 25. As a result, encrustations that may develop at the exit point are created avoided.

In the case of the in FIG. The embodiment of a stage shown in FIG. 4 are those corresponding to FIGS. 2 and 3 Construction elements also have the same reference numbers, which only start with the apostrophe '" are provided, designated.

In this embodiment, at least one static mixing element 26 is arranged in the pipe 10 '", which can be formed in the manner as it is, for. Am

the CH-PS 5 37 208 is described.

In addition, in this exemplary embodiment, both the steam line 14 '", insofar as it is laid within the column V" , as well as the separating tray 11'"and the outlet 12 '" are from a coolant, e.g. B. surrounded by water flowing through the cooling jacket 27 and 28, respectively.

For this purpose 4 sheets of drawings

Claims (11)

Patent claims: 1. Stripping column for solutions or suspensions existing liquids in which solids precipitate during the mass transfer process with the liquid to be driven off in the top part of the column and vapor in its bottom part is fed in, in which the column in several stages by spaced one above the other Dividers divided with drains for the transport of the liquid and the vapor space one lower level via at least one line for the transport of the steam with the one above arranged stage is connected, thereby characterized in that the line (14; 14 '; 14 "; 14'") for the transport of the steam in a through side walls delimited 'tnd open space above and below (10; 10'; 10 "; 10 '") which opens into one above a partition plate (11; 11 '; 11 "; 11 '") located bubble bed (9; 9'; 9"; 9 '") is arranged and that the drain (12; 12'; 12"; 12 '") each stage has means for adjusting the quantity of the draining liquid. 2. stripping column according to claim 1, characterized in that the spaces (10; 10 '; 10 "; 10'") consist of pipes. 3. stripping column according to claim 2, characterized in that static in the tubes Mixing elements (22; 26) are arranged. 4. stripping column according to claim 3, characterized in that as static mixing elements Perforated plates (22) are used. 5. stripping column according to claim 1, characterized in that the steam lines (14 ") on their mouths have funnel-shaped widening outlet openings (25). 6. stripping column according to claim 1, characterized in that the steam lines (14 ") An injection line (24) for liquid in each case in front of their points of opening into the spaces (10 ") connected. 7. stripping column according to claim 1, characterized in that the walls of the steam lines (14 '") within the column (Γ") are at least partially surrounded by a cooling jacket (27). 8. stripping column according to claim 1, characterized in that the walls of the steam lines (14 ") inside the column (1") provided at least in part with a solid insulation are. 9. stripping column according to claim 1, characterized in that the dividing trays (H '") as Raised floors are formed. 10. stripping column according to claim 1, characterized in that the processes (12 '") of a Cooling jacket are surrounded. 11. stripping column according to claim 1, characterized characterized in that the partitions (H ") and the drains (12") are provided with solid insulation are.