WO2025031683A1 - Method for the centrifugal processing of a mixture in a protective gas atmosphere of a separator - Google Patents

Abstract

The invention relates to a method for the centrifugal processing of a mixture (50) in a protective gas atmosphere of a separator (4, 4', 4'') having the following steps: A providing (100) a separator (4, 4', 4''), in particular a separator (4, 4',4'') with a vertical axis of rotation (8), comprising a drum (5) which is mounted to rotate and which has a drum interior for centrifugally processing a liquid (1), wherein the separator (4, 4', 4'') has at least one gas supply line (11, 11', 11''), which opens into the drum interior; B introducing (200) a rinsing liquid (2) into the drum (5) and starting up the separator (4, 4', 4''), wherein at least one air chamber (60) forms in the drum (5) during operation of the separator (4, 4', 4''); C introducing a protective gas (2) through the gas supply line (11, 11', 11'') into the air chamber (60), the air located therein being forced out by the protective gas (2); and D introducing the mixture (50) into the separator (4, 4', 4'') and discharging the rinsing liquid (1).

Description

METHOD FOR THE CENTRIFUGAL PROCESSING OF A MIXTURE IN A PROTECTIVE GAS ATMOSPHERE OF A SEPARATOR

The present invention relates to a method for the centrifugal processing of a dispersion as a solid-liquid or liquid-liquid mixture with the formation of at least two phases in a protective gas atmosphere in a separator.

Creating a protective gas atmosphere is interesting for various applications, such as the food processing industry. For example, apple juice or apple juice concentrate can experience a change in taste due to the influence of atmospheric oxygen. Beer also absorbs oxygen, causing undesirable changes in taste.

The same applies to the various processes of chemical synthesis, which are carried out under protective gas. The processing of the synthesis products is usually carried out using alternative separation methods, such as filtration. Separators, on the other hand, often have one or more air chambers or air cushions during operation, particularly in the area of the distribution chambers, which contain residual oxygen.

EP 3 894 083 A1 discloses a separator and a method for carbonating a liquid, in particular a beverage such as beer. A separate gas supply line extends into the interior of the drum. This document is therefore concerned with a different purpose. Only selected variants of the carbonation variants shown in this document are also suitable for creating a protective gas atmosphere. However, during carbonation, the liquid to be processed is typically introduced first and then enriched with carbon dioxide by introducing CO2. In this variant, air-filled chambers are also initially formed, whereby an undesirable oxidation of an initial fraction of the liquid occurs, especially at the beginning of the processing.

Based on the aforementioned prior art, it is the object of the present invention to provide a method with which a drum or regions of a drum can be placed under protective gas and thereby residual oxygen can be displaced.

The present invention solves this problem by providing a method having the features of claim 1 or alternatively by a method having the features of claim 16. The method relates to the centrifugal processing of a mixture in a protective gas atmosphere of a separator, wherein the protective gas atmosphere prevails in particular in the drum of the separator.

The method comprises providing a separator, in particular a separator with a vertical axis of rotation, and a rotatably mounted drum with a drum interior for centrifugal processing of a liquid.

The drum preferably has a supply pipe and a distribution chamber into which the supply pipe opens.

The distribution chamber can in turn preferably open into a chamber inside the drum with a plate pack and/or into a solids collection chamber inside the drum.

The separator has at least one gas supply line for introducing displacement gas, which opens into the drum interior, and particularly preferably into the distributor space. The gas supply line can comprise a gas line nozzle and a product supply pipe, via which, in addition to the gas supply line, a product can also be supplied to the separator. The existing elements of a separator are thus used particularly efficiently for the gas supply. The gas line nozzle can be arranged in the separator in an area of several outlets from the separator, also known as the discharge head, and can be designed as a lateral connection on the product supply pipe for the gas supply. Alternatively, the gas supply line can also be a separate pipe, e.g. in the product inlet pipe, and run parallel to this product inlet pipe.

The separator enables, for example, a phase separation of a dispersion into two liquid, essentially clarified phases, i.e. a liquid-liquid separation. Alternatively or additionally, a liquid can also be clarified from solids, i.e. a solid-liquid separation of a dispersion of solids and liquid. This creates a flowable sludge phase and a clarified liquid phase. A three-phase separation into two liquid phases and a solid phase, as a sludge phase, is also possible.

In a second step, a rinsing liquid is introduced into the drum. The drum can be empty, partially filled or filled up to the liquid outlet system with grippers. This step reduces the volume of gas to be displaced within the drum. The rinsing liquid can be water or an aqueous solution, for example. The distribution chamber has a Air and therefore also oxygen-filled area. This is undesirable, as it means that the mixture to be processed comes into contact with air. In the case of oxidation-sensitive products, such as drinks or drink precursors such as fruit juice, fruit juice concentrate or beer, contact with atmospheric oxygen can lead to a change in the taste of the drink or drink precursor.

The drum can be put into operation before the flushing liquid is introduced. When the drum rotates, the flushing liquid forms a liquid barrier in the area of the liquid phase drainage system, especially grippers. This prevents air from entering again.

During rotation, the rinsing liquid and the residual air in the drum are distributed in such a way that one or more air chambers are formed, particularly in the distribution chamber and in other areas close to the axis of rotation.

In a third step, the protective gas is introduced into the rotating drum, which is at least partially filled with rinsing liquid. This takes place via the gas supply line. This introduced protective gas can have a higher gas pressure than the air in the air chamber, and can therefore displace the air from the chamber. Alternatively or additionally, the density difference of the introduced protective gas can also promote displacement. The drum is preferably sealed via a hermetic drain, which prevents gas from passing through. The residual oxygen is forced out via a drain line for a clarified liquid. Pre-filling the drum reduces the volume of inert gas to be introduced. It is therefore particularly preferred if there is a higher gas pressure in the air chamber during the introduction of the protective gas than in the environment outside the drum.

Finally, in a fourth step, the mixture or dispersion to be processed is introduced into the separator and the rinsing liquid is drained off, e.g. by displacement through the dispersion. This gradually displaces the rinsing liquid from the drum, whereby a mixture or a phase mixture can be discharged at times.

Finally, the mixture is processed in a protective gas atmosphere in the separator that is low in oxygen compared to air or ideally oxygen-free. In the case of the production of carbonated beverages, in addition to creating the protective gas atmosphere by setting the appropriate pressure, carbonation of beverages such as beer can be carried out analogously to EP 3 894 083 B1 by introducing separating mixture without any reduction in quality due to oxidation products initially occurring during processing.

In addition, an overpressure can be generated and adjusted by the protective gas during the centrifugal separation of the mixture, which prevents the escape of CO2 from the liquid, e.g. in beer or sparkling wine.

Further advantageous embodiments of the method according to the invention are the subject of the subclaims.

The protective gas can be carbon dioxide, nitrogen, a noble gas or a mixture thereof.

It is advantageous if the rinsing liquid is water.

To check whether a protective gas atmosphere has been achieved, it is advantageous if an oxygen sensor is arranged at the outlet of the separator to determine the oxygen content in the liquid that is draining, in particular the rinsing liquid. An oxygen sensor can determine both bound and free oxygen in a liquid, e.g. water. The oxygen can also be measured in a gas atmosphere. It can, for example, drop to a minimum value. The protective gas atmosphere is thus created.

The gas pressure can be adjusted depending on the oxygen content determined in the draining liquid. If, for example, no further change in the oxygen content is detected, the gas pressure can be reduced.

It is also advantageous if the separator has a distribution chamber for the radial discharge of the axially introduced liquid, wherein the gas supply line opens into the distribution chamber or wherein the gas supply line opens into a region of the separator in which several outlets of the separator are arranged, the so-called discharge head.

The mouth of the gas supply line can advantageously be arranged at an axial position, in relation to the axis of rotation, between the upper and lower mouth of an inlet pipe of the separator for introducing the mixture and/or the rinsing liquid into the drum, wherein the inlet pipe extends into the drum. The axial position refers to the axis of rotation, however, the mouth does not have to be on the axis of rotation, but can in particular also be located next to the axis of rotation or even outside the inlet pipe of the liquid into the drum. By If the mouth of the gas supply line is positioned above the mouth of the inlet pipe, the gas is not introduced into the liquid, but into the air chamber above the liquid level.

Alternatively or additionally, the separator may have a drive spindle, wherein the drum is driven via the drive spindle, wherein the gas supply line is formed at least in regions as a channel within the drive spindle, which opens into the drum interior of the drum.

The air chamber is formed during operation of the centrifuge, particularly in the distribution chamber.

After filling with rinsing liquid, the further process takes place without interrupting the operation of the separator.

An oxygen sensor can also be arranged at the outlet of the separator to determine the oxygen content in the liquid flowing out. The gas pressure of the protective gas in the gas supply line can be controlled based on the determined oxygen content.

Alternatively or in addition to the above-mentioned method according to the invention, a method for centrifugal processing of a mixture in a protective gas atmosphere of a separator can also comprise the following steps:

First, the separator is provided analogously to the first method according to the invention.

Then protective gas is introduced by flooding the drum, completely displacing atmospheric oxygen from the drum. The entire interior of the drum initially contains air, which is then displaced by the protective gas as a result of the process.

Finally, the mixture to be processed, which is preferably sensitive to oxidation, is introduced into the separator.

The above-mentioned method avoids the use of a rinsing liquid. However, the consumption of protective gas is considerably higher, since the protective gas must also be fed into and out of the drum at a considerable pressure in order to prevent air from mixing back with the protective gas at the drum outlets. Depending on the type and availability of the protective gas, e.g. argon or CO2, and the respective size of the separator, this procedure can be significantly more expensive than the first process variant.

Both process variants can be combined with the process in which, following the introduction of the mixture, in an optional step E, the mixture is carbonated to produce a carbonated liquid, in particular a carbonated beverage.

The gas supply line can advantageously be designed as a gas supply pipe which is arranged parallel to the inlet pipe outside the inlet pipe, wherein the supply pipe is linearly displaceable such that the mouth of the gas supply pipe assumes a first position for introducing protective gas into the air chamber when introducing protective gas and assumes a second position for direct introduction into the liquid during carbonization in step E. The second position can thus be used for carbonizing the liquid and the first position for optimally generating a protective gas atmosphere.

Furthermore, in both variants of the method according to the invention, the drum of the separator can be hermetically sealed against the supply of oxygen, preferably by introducing protective gas, during operation.

The separator preferably has a further gas supply line, which enables a supply of protective gas into the gripper area, preferably into a barrier chamber adjacent to a gripper, for hermetic sealing.

Further advantages, features and details of the invention emerge from the following description, in which several embodiments of the invention are explained in more detail with reference to the accompanying figures. The person skilled in the art will expediently also consider the features disclosed in combination in the figures, the description and the claims individually and combine them into useful further combinations. They show:

Fig. 1 schematic representation of a method according to the invention using a separator for the centrifugal processing of a liquid;

Fig. 2 schematic sectional view of a first variant of a separator for the centrifugal processing of a liquid in the context of a method according to the invention; Fig. 3 is a schematic sectional view of a second variant of a separator for the centrifugal processing of a liquid in the context of a method according to the invention;

Fig. 4 is a schematic sectional view of a third variant of a separator for the centrifugal processing of a liquid in the context of a method according to the invention;

Fig. 5 Process diagram of an embodiment variant of the method according to the invention;

Fig. 6 Diagram of the decomposition of atmospheric oxygen in a separator without the method according to the invention and using the method according to the invention; and

Fig. 7 schematic sectional view of a fourth variant of a separator for the centrifugal processing of a liquid in the context of a method according to the invention with supply of a protective gas into the peeling chamber (double hermetic);

Fig. 8 schematic sectional view of a fifth variant of a separator for centrifugal processing of a liquid in the context of a method according to the invention; and

Fig. 9 schematic representation of a filled separator.

The design variants described below show different variants of how a gas supply for introducing protective gas into a separator can be implemented. The same components in a separator are designated with the same reference symbols.

Fig. 1 shows the schematic representation of separators as well as the supply and discharge lines required for the process when completely filling the drum with a substantially oxygen-free gas 2. Such a protective gas 2 can be, for example, nitrogen, carbon dioxide or a noble gas or mixtures thereof.

An oxygen-free or oxygen-poor atmosphere in the sense of the present invention refers, of course, to the proportion of molecular oxygen and not to atomic oxygen. Therefore, a CO2 atmosphere is referred to as oxygen-free. Low in oxygen preferably refers to a proportion of molecular oxygen in a region-distributed gas mixture of less than 10 vol.%, preferably less than 5 vol.%, particularly preferably less than 1 vol.%.

To discuss the method, reference is first made to Figs. 1 and 5. In a first step 100, a separator 4 with a gas supply line is provided in the drum.

In a second step 200, a rinsing liquid 1, in particular water, is introduced into the rotating drum of a separator 4 with a vertical axis of rotation. The separator is already rotating when the rinsing liquid 1 is introduced or is set in rotation or in operation before the gas is introduced.

In this case, an area of the drum, in particular the area of the distribution chamber, is not completely filled due to the prevailing centrifugal forces. An air-filled cavity near the axis or several air-filled cavities or air cushions are formed near the axis.

This can, for example, trigger unwanted oxidation of ingredients and/or enzyme activity due to the oxygen content during the production of beverages. Therefore, the rotating drum must ideally be completely free of air pockets.

This is done in a third step 300 by introducing the protective gas, preferably as a substantially oxygen-free gas. The protective gas is introduced with a higher or lower density than air or atmospheric oxygen, which displaces the air or at least the oxygen from the cavity through the rinsing liquid. At the same time, the rinsing liquid forms a water barrier in the peeling chamber, which prevents the supply of air from the outside. For the rinsing liquid, contact with atmospheric oxygen and the passage of atmospheric oxygen as a result of the displacement are not relevant.

In a fourth step 400, the actual dispersion 50 to be processed, e.g. a beverage or a beverage precursor, is introduced into the drum of the separator, which is now under the protective gas atmosphere. The introduction of protective gas can be carried out analogously to some variants of WO 2020/120203 A1, which was used here, however, for the purpose of carbonating liquids. Of course, the carbonization of WO 2020/120203 A1 can be combined with the provision of a protective gas atmosphere. Some selected particularly preferred embodiments of separators for creating a protective gas atmosphere are described below.

Figures 2-4 show the drum system and parts of the drive system of separators, for different variants of gas exchange, air against protective gas, in a drum of the separator.

Fig. 2 shows a first embodiment of a separator 4 according to the invention. The separator 4 has a drum 5. A plate pack 6 is arranged inside the drum 5. The drum 5 is rotatably mounted and has a drive spindle 7 for carrying out a rotational movement about a rotation axis 8.

The separator 4 can be filled in the axial direction via an inlet pipe 15 with the rinsing liquid or with the dispersion 1 to be processed in the atmosphere created by gas introduction.

The inlet pipe 15 opens into a distribution chamber 17, from which one or more distribution channels 12 discharge the respective liquid, i.e. the supplied rinsing liquid or the dispersion, in a radial direction. The respective liquid is then led into one or more bottom chambers 21 and from there via an opening 13 into a centrifugal chamber 14, where solids can be centrifugally separated from the liquid. The centrifugally processed liquid is then led from radially outside to radially inside.

To collect and drain a respective processed first liquid phase 3, the separator 4 has a so-called peeling chamber 9, into which a gripper 10 opens. The peeling chamber 9 is located in the upper area of the separator 4, whereas the drive spindle 7, and possibly a drive unit connected to the drive spindle, are arranged in the lower area of the separator 4. The respective centrifugally processed liquid 3 can then be drained from the separator 4 via the gripper 10, in particular from the peeling chamber, via a drain pipe 16. A solid or sludge phase can be collected in a sludge collection chamber in the hood and drained separately via a line (not shown).

Fig. 2 shows in the first variant of the separator 4 a gas line 11 for introducing the gas into the drum 5. In this variant, this extends parallel to the supply pipe 15, for example within the supply pipe 15. The gas line 11 opens into the distribution chamber 17 of the drum 5. The gas supply line 11 protrudes into the distribution chamber 17 relative to the supply pipe 15. In this variant, the gas is thus introduced in the axial direction, at least after the supply of the rinsing liquid 1 in the drum chamber.

Fig. 3 shows a further variant of a separator 4' for carrying out a method according to the invention. In contrast to Fig. 2, in this variant the gas 2 is introduced radially to the axis of rotation 8 into the distributor chamber 17, in particular into an upper part of the distributor chamber 17, i.e. above the liquid level of the respective introduced liquid. For this purpose the gas supply line 1T extends through the supply pipe 15 and opens radially to the axis of rotation 8 into the distributor chamber 17. In the variants of Fig. 2 too, a space that is significantly smaller than the spinning chamber 14 is used to introduce gas into the drum. In this case it is the distributor chamber 17, which has radial distribution channels 12.

Fig. 4 shows a third variant of a separator 4" for carrying out a method according to the invention. Here, the introduction of gas takes place by means of a gas supply line

11 ’ via the drive spindle 7 and through a drum wall connected to the drive spindle 7. The introduction of gas takes place radially to the axis of rotation 8 in the bottom chamber 21 of the separator 4" in which through the distribution channel(s)

12 the liquid is diverted radially after the axial inlet.

A typical application that is preferred within the scope of the present invention is the carbonation of a beverage, in particular beer, under a CO2 protective gas atmosphere. Carbonation is an enrichment of CO2 in the respective beverage.

Fig. 6 then shows how quickly the oxygen in the air is removed when the process according to the invention is used. While the oxygen content in the conventional variant A only decreases over a very long period of time, the oxygen content in variant B, according to the process according to the invention, is reduced within a very short time by displacing air. Oxidation-sensitive products can already be processed using the separator after this short time.

Fig. 7 shows a schematic sectional view of a fifth variant of a separator for centrifugal processing of a liquid in the context of a method according to the invention. In this case, a gas line nozzle 21 for protective gas is arranged on the feed pipe 15 for product. This gas line nozzle can be attached to the so-called Distributor head 22 can be arranged in which one or more outlets for heavy and light liquid phases are arranged. Product feed pipe 15 and the gas line nozzle form the gas feed line 11"' in this case.

Fig. 8 shows a fourth variant of the invention with a hermetic seal, in particular a double hermetic seal, in the area of the grippers 10 of the drum. This hermetic seal is known from patent application DE 10 2021 10 611 A1, among others. The gas supply line 1T" of Fig. 7 is supplemented by a further gas supply line 23 for protective gas in the area of the grippers. This prevents the entry of ambient oxygen in the area of the gripper, so that the drum is hermetically sealed against the entry of oxygen during processing. The protective gas is introduced via the gas line 23 into a barrier chamber above the gripper 10. Both gas supply lines 1T" and 23 are arranged in some areas in the arrester head 22, whereby in the case of the gas supply line 23 a gas line nozzle 20 also protrudes in some areas from the arrester head 22.

A particular advantage of this “double hermetic” seal is that the supply and discharge of protective gas also means that any oxygen that has diffused through the barrier chambers is absorbed and removed. This further increases the security of being able to avoid oxygen contact with the product.

Fig. 9 shows at which point an air chamber 60 is formed when the separator is filled with rinsing liquid 1. This chamber must be filled with protective gas according to the variant of introducing a rinsing liquid.

reference sign

1 liquid

2 gas

3 liquid

4 separator

4' separator

4” separator

5 drum

6 plate package

7 drive spindle

8 axis of rotation

9 peeling chamber

10 grippers

11 gas supply line

11 ’ gas supply line barrier chamber

11” gas supply drum

11’" gas supply drum

12 distribution channels

13 opening

14 spinning chamber

15 inlet pipe

16 drain pipe

17 distribution room

18 attic rooms

19 peeling chamber

20 gas pipe nozzles

21 gas pipe nozzles

22 distributor head

23 gas supply line

50 Dispersion

60 air chambers

100 Provision of the separator

200 Introduction of the rinsing liquid

300 Introduction of the protective gas

400 Introduction of the mixture to be processed

Claims

patent claims 1. Method for the centrifugal processing of a mixture (50) in a protective gas atmosphere of a separator (4, 4', 4") characterized by the following steps A Providing (100) a separator (4, 4', 4"), in particular a separator (4, 4', 4") with a vertical axis of rotation (8), comprising a rotatably mounted drum (5) with a drum interior for the centrifugal processing of a liquid (1), wherein the separator (4, 4', 4") has at least one gas supply line (11, 1 T', 11 11 "") which opens into the drum interior; B Introducing (200) a rinsing liquid (2) into the drum (5) and starting up the separator (4, 4', 4"), wherein at least one air chamber (60) is formed in the drum (5) during operation of the separator (4, 4', 4"); C Introducing a protective gas (2) through the gas supply line (11 , 11“, 11 11 “”) into the air chamber (60) while displacing the air therein by the protective gas (2) and D Introducing the mixture (50) into the separator (4, 4', 4") and draining the rinsing liquid (1 ), 2. Method according to claim 1, characterized in that the protective gas (2) is carbon dioxide, nitrogen, a noble gas or a mixture thereof. 3. Method according to one of the preceding claims 1 or 2, characterized in that the rinsing liquid (1) is a solvent, in particular water. 4. Method according to one of the preceding claims, characterized in that the gas supply line (1T”) comprises at least one gas line nozzle (21) and a product inlet pipe (15), which preferably opens into a distributor space (17) of the separator (4, 4’, 4”). 5. Method according to one of the preceding claims, characterized in that the method comprises an adjustment of the gas pressure of the protective gas (2) supplied via the gas supply line (11, 1 T, 11”). 6. Method according to one of the preceding claims, characterized in that the protective gas (2) is continuously supplied during operation of the separator (4, 4', 4"). 7. Method according to one of the preceding claims, characterized in that an oxygen sensor is arranged at the outlet of the separator (4, 4', 4") for determining the oxygen content in the outflowing liquid (1, 50). 8. Method according to one of the preceding claims, characterized in that the gas pressure is adjusted depending on the determined oxygen content in the draining liquid. 9. Method according to one of the preceding claims, characterized in that the separator (4, 4”) has a distribution space (17) for the radial discharge of the axially introduced liquid (1 ), wherein the gas supply line (11 , 1 T) opens into the distribution space (17). 10. Method according to one of the preceding claims, characterized in that the mouth of the gas supply line (11, 1T, 11") is arranged at an axial position, in relation to the axis of rotation (8), between the upper and the lower mouth of an inlet pipe (15) of the separator (4, 4', 4") for introducing the mixture (50) and/or the rinsing liquid (1) into the drum (5), wherein the inlet pipe (15) extends into the drum (5). 11. Method according to one of the preceding claims, characterized in that the separator (4”) has a drive spindle (7), wherein the drum (5) is driven via the drive spindle (7), wherein the gas supply line (11”) is formed at least in regions as a channel within the drive spindle (7), which opens into the drum interior of the drum (5). 12. Method according to one of the preceding claims, characterized in that the air chamber (60) is formed in the distribution space (17). 13. Method according to one of the preceding claims, characterized in that steps B-D are carried out without interrupting the operation of the separator (4, 4', 4"). 14. Method according to one of the preceding claims, characterized in that the drum (5) of the separator (4, 4', 4”) is hermetically sealed against a supply of oxygen, preferably by introducing protective gas (2), during operation. 15. Method according to one of the preceding claims, characterized in that the separator (4, 4’, 4”) has a further gas supply line (20) which enables a gas supply of protective gas (2) into the gripper area, preferably into a barrier chamber adjacent to a gripper (10), for hermetic sealing. 16. Method for the centrifugal processing of a mixture (50) in a protective gas atmosphere of a separator (4, 4', 4") characterized by the following steps A Providing (100) a separator (4, 4’, 4”), in particular a separator (4, 4’, 4”) with a vertical axis of rotation (8), comprising a rotatably mounted drum (5) with a drum interior for the centrifugal processing of a liquid (1), wherein the separator (4, 4’, 4”) has at least one gas supply line (11, 11’, 11”) which opens into the drum interior; B Introducing protective gas (2) by flooding the drum (5) while completely displacing atmospheric oxygen from the drum (5); and C Introducing the mixture (50) into the separator (4, 4’, 4”). 17. Method according to one of the preceding claims 1-14, characterized in that following the introduction of the mixture (50) in an optional step E, carbonation of the mixture (50) takes place to produce a carbonated liquid, in particular a carbonated beverage. 18. Method according to one of the preceding claims 1-15, characterized in that the gas supply line (11, 1T) is designed as a gas supply pipe which is arranged parallel to the inlet pipe (15) outside the inlet pipe (15), wherein the supply pipe is linearly displaceable such that the mouth of the gas supply pipe assumes a first position for introducing protective gas into the air chamber (60) when introducing protective gas (2) and assumes a second position for direct introduction into the liquid (1, 50) during carbonization in step E. 19. Method according to one of the preceding claims, characterized in that the gas supply line (1T”) comprises a gas line nozzle (21) and a product inlet pipe (15), which preferably opens into a distribution space (17).