EP2179782A1 - Assembly for introducing liquid carbon dioxide into a medium - Google Patents

Abstract

The liquid carbon dioxide introducing arrangement (1) is provided with a supply tank (2) for liquid carbon dioxide. A fluid-carrying line (8) is connected with the supply tank at an inlet point (7) in a pressure line (6) integrated with a relaxation member, where a pressure above the pressure of the triple point of carbon dioxide is obtained.

Description

The invention relates to an arrangement for introducing carbon dioxide in the liquid state into a fluid medium.

Carbon dioxide is needed for a variety of processes, such as chemical carbonation, neutralizing wastewater or adjusting the pH of drinking water treatment, quick-cooling food and much more.

Many methods involve the use of carbon dioxide in liquid, slurry or pasty substances. Frequently, the carbon dioxide is introduced in gaseous form into the substance to be treated. However, the gas input is often less effective and requires a complex structure in order to achieve a very fine and homogeneous distribution of the gas in the substance to be treated.

Alternatively to the entry in gaseous form, the treatment with solid carbon dioxide (dry ice) comes into consideration. For example, is from the DE 689 12 755 T3 ( EP 0 376 823 B2 ) discloses a system for introducing solid carbon dioxide into a cooling tunnel. This document also describes the introduction of dry ice snow in a liquid-filled pipe. The arrangement described there has a supply line which can be filled with liquid CO ₂ from a tank. In the supply line a valve is provided, which also serves as a relaxation organ. Above the valve, the carbon dioxide is under pressure in the liquid state, downstream of this valve is the carbon dioxide in the desired snow form. In order to prevent the carbon dioxide in the supply line in gas or snow form, a second, flow-connected to the supply line is provided, which is connected to the gas phase of the CO ₂ tank and whose task is the pressure in the line section Keep constantly above the triple point of carbon dioxide before the relaxation organ.

Compared to the above types of entry of the entry of liquid carbon dioxide in a medium is difficult to accomplish, since due to the Triple point of carbon dioxide at about 5.18 bar liquid carbon dioxide can be present only above this value; If the pressure falls below this value, the liquid carbon dioxide partially changes into carbon dioxide snow, partly into gaseous carbon dioxide. If the transition occurs within the carbon dioxide supply, there is a risk that the supply line is blocked due to the accumulating carbon dioxide snow inside.

Object of the present invention is thus to provide a way to introduce liquid carbon dioxide into a fluid medium, in which the risk of icing due to the formation of dry ice snow is minimized.

This object is achieved by an arrangement for introducing liquid carbon dioxide into a fluid medium having the features of patent claim 1.

Further advantageous embodiments are specified in the subclaims.

Thus, according to the invention, a device for introducing carbon dioxide in the liquid state into a fluid medium has a supply tank for liquid carbon dioxide, a pressure line for liquid carbon dioxide connected to the supply tank and opening at a point of entry into a fluid-carrying line. In the pressure line, an expansion element is integrated directly at the junction of the pressure line in the fluid-carrying line, by means of which a pressure above the pressure of the triple point of carbon dioxide can be maintained in a arranged between the supply tank and the relaxation member portion of the pressure line.

The location of the relaxation organ as close as possible to the confluence prevents carbon dioxide snow, which forms during the expansion, from accumulating in the carbon dioxide feed line. At the same time it is ensured that the carbon dioxide is introduced at least partially in the still liquid state in the fluid medium and mixed with the fluid medium. As "fluid medium" is meant here any flowable, liquid, pasty or slurry-like medium. The pressure in the fluid-carrying line may be more or less than the pressure p _{t of} the triple point of carbon dioxide. The entry of carbon dioxide in liquid form has the particular advantage that the carbon dioxide is distributed very homogeneously in the medium; In addition, eliminates the effort that is required for evaporation and / or solidification of carbon dioxide and for entering the finest possible gas bubbles or snow particles. In addition, the relaxation of carbon dioxide within the medium leads to a strong and in many cases desired cooling effect.

A preferred embodiment of the invention provides that the expansion device is designed such that automatically closes below a predetermined pressure in the pressure line. By "predetermined pressure" is meant a pressure p ₁ which is greater than the pressure p _{t of} the triple point of carbon dioxide. If the carbon dioxide is injected too quickly, it is ensured that the pressure in the supply line does not drop below the pressure p _t . A suitable and preferred element of this kind is in the DE 10 2006 027 561.6 described.

It is particularly expedient to design the expansion device as a check valve, which prevents the penetration of fluid medium into the pressure line.

Further preferred is an arrangement in which the check valve is equipped with a valve disk, which is sealingly seated in the closed state of the check valve on a side facing away from the fluid carrying line valve seat valve seat and can be brought by pressure-controlled displacement in the direction of the fluid-carrying line in its open state , The check valve opens by moving the valve disk in the direction of the fluid-carrying line, for example, when the pressure in the pressure line is higher than a preselected value above the triple point of carbon dioxide. This effectively prevents clogging of the valve by ice forming in the fluid.

An advantageous development of the invention provides that lead from the pressure line branch lines, which open with likewise provided with a relaxation organ entry points at a plurality of spaced locations in the fluid-carrying line. The liquid carbon dioxide is in this case several times at spaced points in the same fluid entered. In this way, a particularly effective entry of carbon dioxide is ensured.

Another expedient development of the invention provides that lead from the pressure line branch lines, which open at likewise provided with a relaxation organ entry points into several different fluid-carrying lines. In this embodiment, therefore, a plurality of lines can be supplied from a carbon dioxide tank with liquid carbon dioxide. Of course, it is within the scope of the invention also conceivable to combine this embodiment with the aforementioned, i. Provide feeds to multiple lines or containers and / or multiple feeds in the same line.

Advantageously, a flow control valve and a control unit are provided in the carbon dioxide feed line, upstream of the expansion valve, which regulates the mass flow rate at the flow control valve in dependence on a predetermined program and / or physical or chemical parameters in the medium. In this way, a particularly reliable and accurate metering of the liquid carbon dioxide succeeds.

In a simple and inexpensive embodiment, the flow control valve is designed as open / close valve, i. the valve is either fully open or fully closed.

Fig. 1:

Das Fließschema einer erfindungsgemäßen Anordnung in einer ersten Ausführungsform,

Fig. 2:

Ein bevorzugtes, als Rückschlagventil ausgebildetes Entspannungsventil im Einbauzustand in Längsschnitt,

Fig. 3:

das Fließschema einer erfindungsgemäßen Anordnung in einer zweiten Ausführungsform.

With reference to the drawings, an embodiment of the invention will be explained in more detail. In schematic displays show:

Fig. 1:

The flow diagram of an arrangement according to the invention in a first embodiment,

Fig. 2:

A preferred, designed as a check valve expansion valve in the installed state in longitudinal section,

3:

the flow diagram of an inventive arrangement in a second embodiment.

In the Fig. 1 Arrangement 1 shown comprises a tank 2, which is filled up to the level of a level 3 with liquid carbon dioxide. The tank 2 is, for example, a medium-pressure tank or a heat-insulated low-pressure tank. Via a slide 4 which is located in the interior of the tank 2 liquid phase of the carbon dioxide is connected to a pressure line 6, which opens at an entry point 7 in a line 8, through which the liquid to be treated with liquid carbon dioxide fluid is performed. The pressure line 6 is - as otherwise all coming into contact with carbon dioxide parts of the arrangement 1- preferably made of metal and is designed specifically for the physical and chemical properties of carbon dioxide. In the pressure line 6, a slider 10, a pressure relief valve 11 and flow control valve 12 are successively provided. The slide 10 allows the complete completion of the pressure line 6. By the flow control valve 12, the flow of the tank 2 removed liquid carbon dioxide can be changed. The change in the mass flow is carried out either manually by appropriate operation of the flow control valve 12 or by means of a control unit 14 according to a predetermined program or in dependence on measured parameters. In this case, for example, temperature, pH value of the fluid, concentration of certain ions such as calcium carbonate, etc. in the line 8 downstream of the entry point 7 serve as possible parameters. The mass flow rate can be regulated within a wide range of, for example, 10 to 2500 kg / h , Immediately at the entry point a check valve 15 is arranged in the pressure line 6. The check valve 15 is designed so that it opens only when the pressure in the pressure line 6 above a certain value p ₁ above the pressure p _t (the pressure at the triple point of carbon dioxide) moves; For example, the check valve 15 is set to a pressure value of 6 to 9 bar in the pressure line 6, above which the check valve 15 opens, provided that the pressure in the Line 8 is not even higher.

A preferred embodiment of a check valve 15 is shown in FIG Fig. 2 shown in the installed state. A check valve 15 of this type is for example in the DE 10 2006 027 561.6 described in detail, which is incorporated herein by reference.

The check valve 15 opens into the wall of the fluid-carrying line 8 at an entry point 7 a. The check valve 15 has a closing member 16 which has a valve plate 17 at its end facing the line 8. The valve plate 17 is in - in Fig. 3 shown - opening state of a valve seat 18 in the direction of the fluid-carrying line 8 spaced from and is designed so that it terminates at the front side substantially at the same height with the inner wall of the line 8. The relaxation of the flowing in the check valve 15 connected to the pressure line 6 liquid carbon dioxide takes place only immediately on the valve plate 17 and thus only immediately upon entry of the carbon dioxide in the guided in the conduit 8 fluid. In the closed state, the valve disk 17 sits on the valve seat 18 in a sealing manner. The transition from the closed to the open state (and vice versa) is determined by the difference between the pressure in the conduit 8 and the pressure in the pressure line 6. By means of an adjustable spring element 19, the pressure below which the check valve 15 is in the closed state , additionally varied and, for example, be adjusted so that the check valve 15 opens only above the pressure p ₁ . In this way, with a suitable setting of the pressure p ₁ , the carbon dioxide enters the fluid in a still partially liquid state. If the pressure in the pressure line 6 drops sharply due to an event, the check valve 15 is closed immediately. The penetration of fluid from the line 8 in the check valve 15 or in the pressure line 6 is thus effectively prevented.

The carbon dioxide exiting at the check valve 15 also comes into contact with the fluid in the liquid state even if the pressure within the line 8 is less than p _t and thus the carbon dioxide is released when it exits. Furthermore, this prevents that in the region of the check valve 15 permanently fluid can accumulate. Thus, the arrangement 1 in a special way for the food industry, for example, for drinking water treatment, suitable. The distance between flow control valve 12 and check valve 15 may be between a few centimeters and about 50m. It is crucial that the carbon dioxide in the entire range in the pressure line 6 between the flow control valve 12 and the check valve 15 is in the liquid state.

At the in Fig. 3 shown arrangement 20 are the same parts with the same reference numerals as in Fig. 1 and Fig. 2 Mistake. With the liquid phase of the stored carbon dioxide in tank 2, a pressure line 6 is connected to a slide 4, in which - in the same manner as in the arrangement 1 from Fig. 1 - One after the other slide 10, a pressure relief valve 11 and a flow control valve 12 is provided. According to the embodiment Fig. 2 However, the pressure line 6 branches downstream to the flow control valve 12 in a plurality - in the exemplary embodiment in two - branch lines 21, 22. The branch lines 21, 22 each open at entry points 23, 24 in lines 25, 26 a. The conduits 25, 26 are either conduits through which the same fluid or different fluids flow or flow. Check valves 27, 28, which ensure that the expansion of the carbon dioxide takes place only immediately at the respective entry point 23, 24, and thus that the carbon dioxide is in at least partially liquid state into the respective, in the line 25, are located directly at the entry points. 26 flowing fluid is fed. Similar to the arrangement 1, the carbon dioxide feed is regulated by a control unit 14 here as well. Instead of a volume control via a flow control valve 12 in the pressure line 6, which regulates the simultaneous influx of carbon dioxide in both branches, each separate flow control valves in the branch lines 21, 22 may be provided, care must be taken by means of the control that the pressure in the branch lines to the respective check valves 27, 28 always remains above the triple point pressure of carbon dioxide. Instead of feeding into different lines 25, 26, the branch lines 21, 22 corresponding branch lines can also be used to provide liquid carbon dioxide also at spaced points in the flow path of the same line.

When using the arrangement according to the invention a clogging of pipes with carbon dioxide snow is effectively prevented and thus created at low investment costs but an effective way to bring carbon dioxide in the liquid state in a fluid. An evaporator for the carbon dioxide or an entry device for introducing the carbon dioxide in the form of the finest possible gas bubbles is not required.

• Neutralisation von alkalischen Brauch- und Schmutzwässern,
• Kohlendioxideintrag in Trinkwasser zur pH-Einstellung oder Demineralisation
• Injektion von Kohlendioxid zum Lösen von Kalziumkarbonat oder zur pH-Einstellung in diversen chemischen Prozessen beispielsweise in der Papierindustrie
• Kühlprozesse insbesondere in der Lebensmittelindustrie, beispielsweise zum Frosten oder Krusten von Lebensmitteln.
• Zerstäuben von Produkten.

Preferred ranges in which the invention can be used are, for example:

• Neutralization of alkaline industrial and polluted waters,
• Carbon dioxide entry into drinking water for pH adjustment or demineralization
• Injection of carbon dioxide to dissolve calcium carbonate or to adjust the pH in various chemical processes, for example in the paper industry
• Cooling processes, especially in the food industry, for example, for frosting or crusting of food.
• Sputtering of products.

LIST OF REFERENCE NUMBERS

1.

arrangement

Second

tank

Third

level

4th

pusher

5th

-

6th

pressure line

7th

entry point

8th.

management

9th

-

10th

pusher

11th

Pressure relief valve

12th

Flow Control Valve

13th

-

14th

control unit

15th

check valve

16th

closing member

17th

valve disc

18th

valve seat

19th

spring element

20th

arrangement

21st

branch line

22nd

branch line

23rd

entry point

24th

entry point

25th

management

26th

management

27th

check valve

28th

check valve

Claims (8)

Arrangement for introducing carbon dioxide in the liquid state into a fluid medium, with a supply tank (2) for liquid carbon dioxide, one connected to the supply tank (2) and opening at a point of entry (7) into a fluid-carrying line (8, 25, 26) Pressure line (6) and with a in the pressure line (6) integrated expansion device (15) by means of which in a between supply tank (2) and expansion element (15) arranged portion of the pressure line (6) maintain a pressure above the pressure of the triple point of carbon dioxide can be obtained, wherein the expansion element (15) is arranged directly at the junction of the pressure line (6) in the fluid-carrying line (8). Arrangement according to claim 1, characterized in that the expansion device (15) is designed such that it automatically closes below a predetermined pressure in the pressure line (6). Arrangement according to claim 1 or 2, characterized in that the expansion device (15) as a check valve for preventing the penetration of fluid medium from the conduit (8, 25, 26) is formed in the pressure line (6). Arrangement according to one of the preceding claims, characterized in that the check valve (15) is equipped with a valve disk (31) arranged in the closed state of the check valve (15) on a side remote from the fluid-carrying line (8) of the valve disk (17) Valve seat (18) sealingly seated and can be brought by pressure-controlled displacement in the direction of the fluid-carrying line (8) in its open state. Arrangement according to one of the preceding claims, characterized in that branch lines lead from the pressure line (6), which are provided with entry points likewise provided with an expansion element (15) at a plurality of spaced locations in the fluid-carrying conduit (8, 25, 26). Arrangement according to one of the preceding claims, characterized in that branch lines lead from the pressure line (6), which open into a plurality of different fluid-carrying lines (25, 26) with entry points (23, 24) likewise provided with an expansion element (15). Arrangement according to one of the preceding claims, characterized in that in the pressure line (6), upstream of the expansion valve, a flow control valve (12) and a control unit (14) are provided which the mass flow rate at the flow control valve (12) in response to a predetermined program and / or physical or chemical parameters in the medium. Arrangement according to claim 7, characterized in that the flow control valve (12) is designed as open / close valve.

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