DE4105726C1 - Glass contg. bio-reactor with improved circulation - comprises mixing nozzle composed of first mixing section for mixing microorganism suspension with gas stream, and second section for further adding suspension for final mixing in third section - Google Patents

Abstract

In the bioreactor, in which a suspension of microorganisms on a substrate is mixed with a gas stream in a mixing nozzle, the nozzle has a first mixing section (A), in which the gas stream (I) is mixed with the fluid stream of the substrate input (III), forming a suspension mixture which passes to a second mixing section (B). In the second section, substrate suspension drawn in from the reactor vessel via a suction channel (22) is added to the mixture and mixed with it in a third mixing section (C). ADVANTAGE - Improved circulation

Description

The invention relates to a method for the operation of fumigated bioreactors to improve the loop-shaped Circulation of one placed in the reactor vessel a substrate and existing microorganisms Suspension with a gas stream in a Mixing nozzle is mixed, the circulation of the resulting Phase mixture outside the mixing nozzle in the reactor vessel he follows. The invention further relates to a Device for the operation of fumigated bioreactors Implementation of the process, consisting of a reactor vessel with an inside open on both sides Tube, the upper end of which is opposite a mixing nozzle, by means of which the gas entry and the substrate entry are miscible and can be pressed into the tube, the mixing nozzle in the Reactor suspension is designed diving, with one entry opening each for gas entry and substrate entry, an outlet for the phase mixture, the mixing sections and at least one suction opening for the substrate suspension.  

They are fully mixed reactors for biocatalytic processes known in which raw materials utilizing the synthetic potential living microorganism cells in defined Products are converted (utilities) or organically contaminated processes by microorganisms mineralized, d. H. be cleaned (waste management).

It is also known to meet these types of reactor requirements different versions, such as fumigated Loop fermenter with a material cycle. The loop reactors used have a defined directed internal or external circulation (Journal "Chem. Ing. Techn.", 1974, 46, 701). Furthermore is known a compact reactor, which is inside the closed Reactor a tube open on both sides owns. A mixing nozzle is arranged at the upper end of the tube, with the the gaseous components and the suspension be pressed into the inner tube. The clarified suspension is partly arranged in a next to the reactor Sedimentation vessel, while the other part by means of Pump is fed back to the mixing nozzle. Another part still in the reactor is at the top of the Inner tube through the suction effect of the two-fluid nozzle in the Inner tube sucked back, the gas bubbles and the bacterial flakes be dispersed again. From the settling tank becomes the cleaned wastewater and part of the organic sludge dissipated. The other part of the bio sludge is in the reactor returned.

It is known from German patent specification 9 20 844 that fumigation a suspension by means of an engine driven centrifugal wheel to improve that with holes provided and provided in the upper part of the guide tube is. A screw can feed the suspension inside  convey the guide tube to the centrifugal wheel. Corresponding it is also the DE utility model 70 32 241 possible to arrange the bioreactor horizontally in its longitudinal axis, to increase the power requirement for mixing reduce, because then the gas supply takes place at low pressure can.

It is also known from DE-Ausletschrift 24 33 414, to place the centrifugal wheel near the bottom of the reactor, so this together with an annular constriction in the guide tube at its upper end by the arrangement of a gas supplying body is caused Gasing the suspension causes. By that of that The impeller generated downward suction of the suspension, which caused it their greatest flow velocity in the annular constriction the gas is sucked in.

In the facilities described last, it is disadvantageous that the turbulence with motor-driven, mechanical Aids are made so that a significant supply of energy is inevitable.

The invention has for its object a method and a device for the operation of such bioreactors to create with which a further improvement of the micro-gentle oxygenation in the suspension of a Bioreactor contents to increase the microbial metabolic activity is achieved, the flow and vortex processes be improved in the reactor vessel as well better use of the biomass is made, however without motor-driven swirling devices should be used.

According to the invention the object is achieved in the method mentioned in that upper part of the mixing nozzle the gas flow in a first  Mixing section mixed with the fluid jet of the substrate entry is that the resulting suspension mixture reaches a second mixing section, in which the suspension mixture via a suction channel from the reactor vessel sucked substrate suspension fed and in another Mixing section is mixed with this.

Furthermore, the task is performed by the device mentioned at the beginning Carried out this procedure in which the suction opening with an annular channel formed in the mixing nozzle related and the gas entry at the end of the first Mixing section are designed to take place over a ring channel.

Further advantageous embodiments of the invention go from the subclaims in connection with description and Drawing.

The advantages achieved with the invention are in particular in that - without motorized swirling devices - in addition to the generation of turbulence, the necessary high proportion of oxygen can be introduced in a way that is gentle on the micro can. Since the biochemical oxidation dissolved oxygen in the liquid phase for a turbulent system in the closest approximation quantitative is proportional to the oxygen in the air, this means a more suitable environment for obligatory microbes. By using suitable flow parameters the shear stress is minimized so that only the bacterial agglomerates mechanically crushed or be dissolved and thus a separation of the Microorganisms is reached. This creates great Surfaces that are easily accessible to substrate and oxygen are and promote the removal of metabolic products. Thus, a very high proportion of the microbes can unite perform effective metabolism. The invention  Solution enables an energy-saving, trouble-free, environmentally friendly operation of the bioreactor. Across from Known solutions will provide a significant performance boost achieved with the same efficiency.  

The invention is based on an embodiment are described in more detail below.

The accompanying drawing shows:

Fig. 1 shows the schematic system construction of a reaction chamber in section, with the flow guide and presentation of the material flows, strong,

Fig. 2 shows a portion of a mixing nozzle with a coiled central part in longitudinal section;

Fig. 3 shows a portion of a mixing nozzle with a helical outer surface in longitudinal section;

Fig. 4 shows a section according to line IV-IV in Fig. 5,

Fig. 5 shows a mixing nozzle according to the invention with three-stage mixing section in longitudinal section;

Fig. 6 shows a further embodiment of a mixing nozzle according to the invention in longitudinal section and

Fig. 7 shows a mixing nozzle corresponding to Fig. 5, but with a two-stage mixing section.

Fig. 1 shows a valve disposed in the interior of a reactor vessel 10 tube 4. A mixing nozzle 1 sits above the tube 4 in a perforated centering disk 7 and presses the reactor suspension I + III in the tube 4 downwards. At the bottom 9 of the reactor vessel 10 , it is deflected outwards by its annular configuration and rises in the space 5 between the tube 4 and the jacket of the reactor vessel 10 . The cross-sectional ratios are selected so that a pressure release occurs when entering the space between the tube and the recorder container 10 . A large partial volume flow (shown in dotted lines) is drawn in through the suction openings 6 of the mixing nozzle 1 , mixed with the substrate and fed back into the circuit. Part of the liquid can also be sucked in again by the pump 2 , in order then to be fed again in the mixing nozzle via the line 16 . Optimal mixing is ensured by reactor geometry. In order to obtain a safe loop-shaped flow guidance, there is a deflection ring 8 above and to the side of the tube 4 , which deflects the rising fluid masses towards the central axis of the reactor vessel 10 , so that they are directed in the area of the suction nozzles 6 of the mixing nozzle 1 . Part of the gas introduced is also sucked in again in order to be dispersed again. This increases the oxygen utilization considerably. The centering disk 7 ensures reliable fluid jet guidance from the nozzle into the axis of the tube 4 . This centering disk 7 additionally retains the rising gas phase. As a result, gas can additionally be supplied to the suction opening 6 of the third mixing section C (see FIGS. 5/6) of the mixing nozzle 1 . This increases the oxygen utilization even further. In order to obtain a reaction zone free from dead zones, the base 9 is designed like a diffuser curved by 180 °. A facilitated outflow from the tube 4 is also achieved here by its slight expansion. The cleaned, discharged liquid is passed from the water surface via a substrate discharge II into a sedimeter 11 . For the recovery of the biomass, the sediment 11 is connected to a substrate entry III via a pump 23 and a line 12 . The cleaned liquid is discharged by means of a sewage line 13 .

Figs. 2 and 3 show how the accelerated by the pump fluid jet 2 of the substrate entry III by a helical groove 17, 18 is placed on the inner or outer wall of an annular die 19 in a rotary motion; the ring nozzle 19 is an (upper) part of the mixing nozzle 1 .

In FIG. 4, the tangential feed of the substrate is shown the entry 19 III into a deflection space of the annular die.

Figs. 5, 7 and 6 show two different embodiments of a mixing nozzle. 1 The main difference between the two embodiments is that in the mixing nozzle according to FIG. 5 the introduction of the substrate III takes place radially to the direction of flow within the mixing nozzle 1 , while in the mixing nozzle according to FIG. 6 the substrate III is carried out in the longitudinal direction of the mixing nozzle 1 .

The gas input I takes place in the mixing nozzle according to FIG. 5 via a nozzle 20 which is provided with a channel and is surrounded by an annular channel 19 . Via the connection III, the substrate is pressed into the mixing nozzle 1 via the line 16 and then enters the annular channel 19 . By means of helical recesses 17 on the outside of the nozzle 20 , the substrate III is additionally set in rotation, so that the gas and substrate are mixed very well in the first mixing section A. The gas input I is carried out not only via the nozzle 20 but also via an annular channel 21 which is connected to the gas input I via a channel 24 . This ring channel opens at the end of the mixing section A on the outside of the fluid flow, so that an intimate mixing of gas and substrate takes place in the subsequent second mixing section B. In the embodiment according to FIG. 7, the central nozzle 20 is omitted, so that the gas is supplied exclusively via the annular channel 21 . A third mixing section C follows the second mixing section B, the diameter of the mixing section C being larger than that of the mixing section B. In the transition region of the mixing section B into the mixing section C, a further annular channel 22 is arranged, which is connected to the suspension in the reactor vessel 10 via suction openings 6 . A negative pressure is generated in the mixing nozzle by the flow rate of the substrate in the mixing nozzle 1 , so that reactor suspension and gas are sucked in via the suction openings 6 and the annular channel 22 and mixed with the substrate in the following mixing section C.

In the exemplary embodiment according to FIG. 6, 3 mixing sections A, B, C are likewise present, the gas being introduced on the one hand in the center via the nozzle 20 and on the other hand on the circumference via an annular channel 21 . The formation of the suction openings 6 and the annular channel 22 in the transition region of the second mixing section B into the third mixing section C is designed in accordance with the exemplary embodiment according to FIG. 5.

The substrate entry III takes place via a channel 25 which opens into an annular channel 19 which surrounds the nozzle 20 . The mixing of the gas entry I and the substrate entry III takes place in two stages in the mixing section A and then in the mixing section B, the gas stream being added here again via an annular channel 21 on the periphery.

The particular advantage of those designed according to the invention The mixing nozzle lies in the layered feed and the mixing rotation of the gas-liquid phases. Here is the ratio of rotation to translation in the nozzle balanced in the propellant jet so that an intimate Mixing and no separation takes place. Of particular Another advantage is the three-stage structure of the nozzle. The first two mixing sections A and B are used enrichment with oxygen and equal distribution of phases, while before the third mixing section C Suspension and gas sucked in from the reactor room and is mixed again with the incoming phases. Consequently becomes the dwell time of the phases in the reactor room significantly shortened and gas utilization increased. This allows the reaction space to be used even more intensively or made smaller with the same metabolic rate will. The substrate turnover can therefore be related on the oxygen supply through the third mixing section C can be increased again.

It should be pointed out in particular that the helical configuration results in a large rotational proportion of the liquid phase in the ring nozzle, which leads to a high suction pressure due to the centrifugal force which arises in the nozzle center axis and thus to an increase in the gas volume flow sucked in. The subsequent mixing section A, due to the high relative speed of the particles (gas / liquid / flakes) to one another, ensures thorough mixing both in the axial and in the radial direction, via a further annular channel 21 at the end of the mixing section A, a further gas component is supplied , Here on the dimensioning of the inlet gap, by the rotating jet with its 1000 times higher density compared to the gas and by the high relative speed in the longitudinal direction of the mixing nozzle, as well as by the described design of the gas routing, an extremely intensive mixing is obtained.

The most important parameters for oxygen transfer are summarized in the so-called mass transport equation:

The resulting mass flow of oxygen per liquid volume V _{L of} the reactor tank results from the product of mass transfer coefficients k _L (m / s), specific phase interface a (m² / m³) and the driving oxygen concentration gradient (c₀-c) in the unit kg / m³, where c₀ is the saturation solubility (kg / m³) and c is the concentration in the mass of the liquid.

Claims (12)

1. A method for the operation of fumigated bioreactors to improve the loop-shaped circulation of a suspension, which is introduced into the reactor vessel and consists of a substrate and microorganisms therein, which is mixed with a gas stream in a mixing nozzle, with the circulation of the resulting phase mixture outside the mixing nozzle takes place in the reactor vessel, characterized in that in the upper part of the mixing nozzle ( 1 ) the gas stream (I) is mixed in a first mixing section (A) with the fluid jet of the substrate entry (III), that the resulting suspension mixture into a second mixing section (B ) arrives, in which substrate suspension (I '+ III') sucked in from the reactor vessel is fed into the suspension mixture via an intake channel ( 22 ) and is mixed with it in a further mixing section (C). 2. The method according to claim 1, characterized in that the gas entry (I) in the mixing section (A) at two points spaced in the flow direction ( 20, 21 ), the one entry ( 20 ) in the middle of the stream and the second entry ( 21 ) on the outside of the current. 3. The method according to claim 1 or 2, characterized in that the substrate entry (III) is set in rotation by guide surfaces ( 17, 18 ). 4. The method according to any one of claims 1 to 3, characterized characterized in that within the first mixing section (A) the ratio of the propulsion jet vectors for the mixture translation and rotation greater than 1 is. 5. The method according to any one of claims 1 to 4, characterized in that the exit speed of the mixture from the mixing nozzle ( 1 ) is so great that reactor suspension is sucked out of the space ( 5 ) and fed into the tube ( 4 ). 6. Device for the operation of fumigated bioreactors for carrying out the method according to any one of claims 1 to 5, consisting of a reactor vessel with an internally arranged tube open on the inside, the upper end of which is opposite a mixing nozzle, by means of which the gas entry and the substrate entry are miscible and can be pressed into the tube, the mixing nozzle being designed to be immersed in the reactor suspension, each with an inlet opening for the gas entry and the substrate entry, an outlet opening for the phase mixture, the mixing sections and at least one suction opening for the substrate suspension, characterized in that the suction opening ( 6 ) communicating with an annular channel ( 22 ) formed in the mixing nozzle ( 1 ) and the gas input (I) at the end of the first mixing section (A) via an annular channel ( 21 ). 7. Device according to claim 6, characterized in that a centrally into the mixing nozzle ( 1 ), from the inlet opening for the gas entry (I) fed line ( 20 ) for a first part of the gas entry (I) and one in the wall of the Mixing nozzle ( 1 ) designed annular channel ( 21 ) are provided for a second partial flow of gas entry (I), via which the gas entry (I) can be introduced into the first mixing section (A). 8. Device according to one of claims 1 to 7, characterized in that the mixing section (A) of the mixing nozzle ( 1 ) on the inner wall or outer wall arranged helical recesses ( 17; 18 ) or helical webs. 9. Device according to one of claims 1 to 8, characterized in that the reactor vessel ( 10 ) below the tube ( 4 ) has a bottom ( 9 ) with circumferential annular depressions. 10. Device according to one of claims 1 to 9, characterized in that a circumferential deflection ring ( 8 ) is arranged in the reactor vessel ( 10 ) at the upper region of the tube ( 4 ). 11. The device according to claim 10, characterized in that the outlet cross section from the tube ( 4 ) by the design of the bottom ( 9 ) is smaller than the cross section between the reactor wall and tube ( 4 ). 12. Device according to one of claims 1 to 11, characterized in that a perforated centering disc ( 7 ) is provided for the fluid jet guidance over the tube ( 4 ).