DE102007049077A1 - Device for introducing gas in liquid medium in container, has lower open pulse tube and is subjected above homogeneous gas pressure impulses - Google Patents

Abstract

The device has a lower open pulse tube (3) and is subjected above homogeneous gas pressure impulses. The pulse tube is subjected to the homogeneous gas pressure impulses in such a way that an oscillating fluid movement takes place in the pulse tube at the lower outlet of the pulse tube. A part of air is squeezed periodically from the pulse tube as bubble into the liquid (10) of the container. An independent claim is included for a method for inserting gas in a liquid.

Description

The The invention relates to an apparatus and method for entry of a gas in a liquid medium, such. B. in bioreactors or in chemical reaction reactors.

Known Methods and apparatus for fumigating liquids based on motorized stirring systems, apply a pneumatic Fumigation or use static devices for blistering and distribution. Depending on the material system, type of device and task becomes one of these variants or a combination of variants the preference given or it will build on this special constructions and design variants realized.

These Fumigators each have specific disadvantages, the lead to the use or efficiency of the mission in a number of cases u. U. is very limited.

So the motor driven stirring systems are often in view the structural design of the stirring tool, the shaft passage and the drive very expensive, generate z. T. high shear stresses and can be used with potentially explosive substance systems To cause problems. Especially in bioreactions it is important To avoid high shear stresses and a uniform gas input to reach. Their use is also with liquids very fine, very coarse or abrasion-sensitive solids barely reasonably possible.

pneumatic Fumigation systems, such. B. in airlift, loop or jet reactors applied, are bound to certain apparatus designs, have only a limited gas input rate and are coarsely disperse Suspensions often can not be used.

static Gas distributor without mechanically or pneumatically initiated liquid movement allow only a relatively small gas input, require high gas pressures and hardly produce the desired Mixing or circulation of the liquid. outgoing from this situation were various advancements and Inventions, u. a. also to the principle of gas entry, made.

That's how it describes DE 10050030 a method and apparatus for generating large active interfaces that allow high gas input into the liquid. This is achieved by a corresponding design and arrangement of a motor-driven rotor, which is surrounded by a rotatable rotor with blades and moves in the area of the liquid surface.

In DE 2514197 a device for the gassing of liquids with a gas distributor and a vibration device is shown. The gas distributor can be moved parallel to the gas outlet openings and thereby allow better bubble formation and fluid movement.

The application of a vibration chamber with at least one elastic back and forth movable wall is in DE 3543022 described. Due to the vibration, the gas in the chamber is compressed pulsatingly, which has a favorable effect on the formation of bubbles and the mass transfer.

To produce a gentle effect of stirring is used in DE 3923928 specified stirring tool. It has a drive for generating special trajectories of the stirring elements, such. B. elliptical or wobble-like movements. This type of movement is complemented by the nature of the storage and various design variants of the stirring tool. The measures serve to reduce the shear forces occurring in the treatment room.

In DE 3739650 describes a fermenter for growing cell cultures on suspended carrier bodies with improved oxygen uptake and at the same time preserving the cell cultures. A Siebbelüfter is arranged eccentrically to the stirrer axis. This device is supplemented by baffle plates, which are connected to a vibration drive.

The application of resonant vibration to improve oxygen supply to cell cultures in bioreactor with hollow fibers is described in US Pat DE 10211106 explained. The oxygen entry is pulsating at a pulsation frequency of 1 to 6 s ^-1 .

in the The purpose of a further development of the prior art is the present invention, the object of a gassing to create no moving mechanical parts in the treatment room owns, produces relatively low shear forces and also for Suspensions is well suited. In addition, the device should apparatus simply designed and the operation of the gassing at a reasonable energy consumption possible.

Of the The invention thus relates to a device and a method for fumigation of liquids and suspensions in chemical multiphase reactors, in bioreactors or in other apparatus explained Art.

This object is achieved in that in the treatment room ( 9 ) a downwardly open vertical tube ( 3 ) - hereinafter referred to as pulse tube - a brought up, the above ( 7 ) is pressurized periodically with compressed gas so that the liquid or the gas-liquid mixture in the pulse tube ( 3 ) is also placed in a periodic up and Abbewe movement. In this case, the pulse-like pressurization is to be designed so that a portion of the supplied pulse gas through the lower opening ( 11 ) of the pulse tube ( 3 ) bubble-like into the treatment room ( 9 ). At the same time, a certain circulation and mixing of the liquid ( 9 ) on. The periodic application of compressed gas to the pulse tube ( 3 ) is realized by a mutual opening and closing of solenoid valves in the gas paths. In a first cycle compressed gas flows ( 5 ) into the pulse tube ( 3 ) and generates at the exit ( 11 ) Bubbles in the liquid ( 10 ). During this time, the gas path ( 6 ) closed. In the second cycle, the gas path ( 5 ) closed and the pulse gas flows over the way ( 8th ) and ( 6 ). For this purpose, two 2/2-way valves - one valve for the compressed gas supply ( 5 ) and for the pulse gas discharge ( 6 ) - or a 3/2-way valve in the gas path ( 8th ) are used. The control of the solenoid valves (alternating frequency and opening times) is controlled by the pulsation control unit ( 7 ) realized. As a result of the pulse-like pressurization, an oscillatory movement of the fluid between the pulse tube (in the region of the lower output of the pulse tube) is formed ( 3 ) and container liquid ( 10 ) out. The return movement into the pulse tube is due to the different liquid level and the periodically constructed pressure increase in the upper gas space ( 14 ) causes. The lower edge of the pulse tube ( 12 ) can be sharp-edged, rounded or crown-shaped and the lower exit ( 11 ) of the pulse tube may be narrowed in diameter or expanded with respect to the entire pulse tube.

Surprisingly, depending on the type of pulsation and on the geometric conditions, typical pulsation frequencies were found which produce relatively high gassing rates and mixing effects. By an appropriate design of the lower pulse tube edge ( 12 ) and the insertion of a baffle into the pulse tube, the gassing rate can be increased.

1 shows in a diagram by way of example a device according to the invention. Here is in a cylindrical container ( 1 ) with a conical bottom ( 13 ) a central pulse tube ( 3 ), which has a smooth edge ( 12 ) and inside a baffle ( 9 ) owns. The container is equipped with a lid ( 2 ) above, so that in the upper gas space ( 14 ) can build up a certain overpressure. The derivation of the Pulsations- or process gas from the container via the departure ( 15 ). The mean fluid level and also the range of movement of the fluid in the pulse tube ( 3 ) depend on the frequency of the pressurization and the effective pressure of the pulse gas. If no additional fumigation according to 2 is used, the periodic liquid movement in the pulse tube is always to be obtained in such a way that a part of the pulse gas flows over the pulse tube edge ( 12 ) in the treatment room ( 10 ) is pressed. In this case, depending on the type of pulsation, the design and the arrangement of the pulse tube form more or less large gas bubbles which are moved in the liquid.

The combination of pulse tube and gas distributor in a container with a curved bottom is in 2 exemplified. By the combination of pulse tube gassing ( 11 ) with an additional static fumigation ( 17 ) an increase in the gas input is achieved. It is also a gas entry only via the gas distributor ( 17 ) possible. In this case, the liquid moves in the pulse tube only above the output ( 11 ), so that no Pulsationsgas is pressed from the pulse tube in the treatment room. The pulsatile liquid oscillation causes an influence on the bubble size, the bubble movement and a mixture of the liquid ( 10 ).

In 3 a further variant of the gassing technique according to the invention is shown. In the upper area of the container is a pulse gas chamber ( 19 ). This pulse gas chamber can by a partition ( 18 ) are formed over the entire container surface or by a partial separation. The use of the pulse gas chamber has the consequence that the passage of the pulse tube through the lid ( 2 ) and the supply of compressed gas can be arranged almost anywhere in the lid.

Another design example of the inventive pulse tube technique for gassing shows 4 , Here are four similar pulsation tubes ( 3 ), which open at the top in a pulse gas chamber, arranged circularly in the container. As a result, an enlargement of the range of the pulse tube gassing and a better gas bubble distribution are achieved. These effects have a positive effect, especially in the case of a curved container bottom or flat bottom.

The Application of the invention will be described in more detail below by way of examples described.

Example 1:

In an apparatus according to 1 with 2.5 l of usable volume 1.2 l of water ( 10 ) and removed by the addition of an appropriate amount of sodium sulfite dissolved in the water oxygen. Subsequently, a gassing of the liquid ( 10 ) with air. For this purpose, the pulse tube ( 3 ) is acted upon with pulsed compressed air so that a subset of the pulsation air bubble-like over the lower opening ( 11 ) of the pulse tube into the liquid ( 10 ) arrived. In doing so, 20 lh ^{-1 of} air were discharged via the exit ( 15 ) dissipated. Due to the oscillatory motion of the liquid, the bubbles were moved along and went up into the gas space ( 14 ). The pulse tube was not equipped with a baffle. The ratio of vessel diameter to pulse tube diameter was 7.5. The compressed air pulsation was generated by means of a 3/2-way valve. The pulsation frequency was 5 s ^-1 . The pulsation air ( 5 ) had an overpressure of 0.18 bar.

An oxygen input rate of 0.81 gl ^-1 h ^{-1 was} measured.

By using a baffle ( 9 ) in the pulse tube ( 3 ), the entry speed increased by about 40%.

Example 2:

In an apparatus according to 2 1.1 l of water were used with 1.9 l of usable capacity ( 10 ) and, as in Example 1, the dissolved oxygen is removed in the water. This was followed by a gassing of the liquid ( 10 ) with air. For this purpose, the pulse tube ( 3 ) is acted upon with pulsed compressed air in such a way that a subset of the pulsation air bubbles through the lower opening of the pulse tube into the liquid ( 10 ) arrived. An additional fumigation took place ( 16 ) by means of a gas distributor ( 17 ) in the ground area. It was 150 lh ^-1 air over the exit ( 15 ) dissipated. The ratio of the diameter of the container to the diameter of the pulse tube was 10. The compressed air pulsation was measured by means of two 2/2-way valves, one valve each for the airways ( 5 ) and ( 6 ), realized. The pulsation frequency was 4 s ^-1 . The pulsation air ( 5 ) had an overpressure of 0.14 bar.

An oxygen uptake rate of 0.49 gl ^-1 h ^{-1 was} measured.

Example 3:

In an apparatus according to 3 with 0.8 l of usable volume, 0.5 l of water ( 9 ) filled. By adding an appropriate amount of sodium sulfite, the dissolved oxygen was removed. Subsequently, a gassing of the liquid ( 9 ) with air. For this purpose, the pulse gas chamber ( 19 ) is acted upon with pulsed compressed air so that a subset of the pulsation air bubbles through the lower opening ( 11 ) of the pulse tube into the liquid ( 9 ) arrived. In doing so, 25 lh ^{-1 of} air were delivered via the exit ( 15 ) dissipated. The ratio of the diameter of the container to the diameter of the pulse tube was 11. The pressure pulsation was designed using a 3/2-way valve. At the head of the pulse tube, a sterile filter was connected in the gas path of the pulsed compressed air. The pulsation frequency was 20 s ^-1 . The pulsation air ( 5 ) had an overpressure of 0.15 bar.

An oxygen uptake rate of 0.45 gl ^-1 h ^{-1 was} measured.

Example 4:

In an apparatus with four pulse tubes according to 4 1.1 l of water were used with 1.9 l of usable capacity ( 10 ) and the dissolved oxygen is removed as in Examples 1-3. Subsequently, a gassing of the liquid ( 10 ) with air. For this purpose, the pulse gas chamber ( 19 ) is acted upon by pulsed compressed air so that a subset of the pulsation air ( 11 ) bubble-like through the lower openings of the four pulse tubes into the liquid ( 10 ) arrived. It was 35 lh ^-1 air over the exit ( 15 ) dissipated. The area ratio of container to the pulse tubes was about 40. The compressed air pulsation was carried out by means of a 3/2-way valve. A pulsation frequency of 22 s ^{-1 was} set. The pulsation air ( 5 ) had an overpressure of 0.15 bar.

For these conditions, the oxygen input rate was 0.41 gl ^-1 h ^-1 .

1

container

2

container lid

3

pulse tube

4

upper Gas space in the pulse tube

5

Pressure gas supply

6

Pulse gas discharge

7

Pulsationssteuergerät

8th

compressed gas

9

baffles in the pulse tube

10

liquid space

11

Pulse tube outlet

12

lower Edge of the pulse tube

13

ground of the container

14

upper Gas room in the tank

15

gas discharge from the container

16

additional gas supply

17

gassing, gas distributor

18

partition wall between container and pulse gas chamber

19

headspace the pulse gas chamber

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10050030 [0007]
• - DE 2514197 [0008]
• - DE 3543022 [0009]
• - DE 3923928 [0010]
• - DE 3739650 [0011]
• - DE 10211106 [0012]

Claims (15)

Device for gassing a liquid medium in a container with a pulse tube open at the bottom, characterized in that the pulse tube is acted upon above with uniform gas pressure pulses so that the oscillating liquid movement takes place in the pulse tube to the bottom output of the pulse tube and that part of the air periodically from the pulse tube is pressed as bubbles in the liquid of the container ( 1 ). Device according to claim 1, characterized in that that the container is closed and over the liquid in the treatment room, a gas volume with an overpressure located opposite the surroundings. Device according to claims 1 and 2, characterized in that in the upper region of the container, a separate chamber is designed, which is acted upon by the pressure pulses and down into a pulse tube ( 3 ). Device according to claims 1 to 3, characterized that a plurality of pulse tubes, preferably arranged concentrically, used become. Device according to claims 1 to 4, characterized in that the pulse tube inside with a baffle Is provided. Device according to claims 1 and 2, characterized in that the pulse tube in the upper region of a cylindrical or conical or spherical Extension has. Device according to claims 1 and 6, characterized in that the lower edge of the pulse tube ( 12 ) sharp-edged, rounded or crown-shaped and the lower exit ( 11 ) of the pulse tube narrows in diameter or is widened with respect to the entire pulse tube. Device according to claims 1 and 7, characterized in that the container bottom flat, curved or conical. Device according to claims 1 to 8, characterized in that the generation of the pressure gas pulses on Head of the pulse tube by changing opening and closing is done by one or more solenoid valves. Apparatus and method according to the claims 1 to 9, characterized in that in the supply and exhaust streams one or more gas filters are inserted. Device according to claims 1 to 8, characterized in that the periodic pressurization with the help of a motor or pneumatic moving elastic Membrane takes place. Process according to claims 1 to 11, characterized in that the frequency of the pressurization is preferably 2 to 25 s ^-1 . Method for using the device according to claims 1 to 10, characterized in that in addition to the pulse tube gassing a gas supply takes place in the lower region of the container liquid ( 2 ). Use of the device according to the claims 1 to 13, characterized in that the Pulsrohrbegasung for Oxygen input is used in bioreactors. Use of the device according to the claims 1 to 13, characterized in that the Pulsrohrbegasung for Gas input in chemical gas-liquid or gas-liquid-solid reactions is used.