Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/20—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles with liquid as a fluidising medium
  • B01J8/22—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles with liquid as a fluidising medium gas being introduced into the liquid
  • B01J8/224—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles with liquid as a fluidising medium gas being introduced into the liquid the particles being subject to a circulatory movement
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
  • C12M23/00—Constructional details, e.g. recesses, hinges
  • C12M23/02—Form or structure of the vessel
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
  • C12M27/00—Means for mixing, agitating or circulating fluids in the vessel
  • C12M27/18—Flow directing inserts
  • C12M27/24—Draft tube
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
  • C12M29/00—Means for introduction, extraction or recirculation of materials, e.g. pumps
  • C12M29/02—Percolation
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
  • C12M33/00—Means for introduction, transport, positioning, extraction, harvesting, peeling or sampling of biological material in or from the apparatus
  • C12M33/10—Means for introduction, transport, positioning, extraction, harvesting, peeling or sampling of biological material in or from the apparatus by centrifugation ; Cyclones

Definitions

• an exchange of matter takes place between immiscible phases, e.g. solids/liquid phases, liquid/liquid phases, gas/liquid phases, gas/liquid/solids phases, or some other combinations, e.g. involving a plurality of different phases of the same kind in combination with one or more different phases of another kind.
• immiscible phases e.g. solids/liquid phases, liquid/liquid phases, gas/liquid phases, gas/liquid/solids phases, or some other combinations, e.g. involving a plurality of different phases of the same kind in combination with one or more different phases of another kind.
• the common feature of production processes of this kind is that the exchange of matter will take place through the boundary face between the different phases, and that the amount of matter exchanged (the substance or mass transport) per unit time is, amongst others, directly related to the area of the common boundary face between the different phases involved. This can be expressed by the equation:
• k the transport coefficient, i.e. a constant independent of the boundary face area but dependent of other conditions (e.g. the concen ⁇ tration of the matter, the temperature, pres ⁇ sure, and possibly viscosity and flow condi ⁇ tions),
• the production of substance per unit time will depend upon the above exchange of matter taking place between the different phases involved, whereby is meant that if this exchange of matter does not take place sufficiently rapidly or is prevented totally, that will constitute a limitation of or possibly a complete hin ⁇ drance to the production of the substance or substances desired per unit time (in the following briefly designated the production rate).
• the production rate For this reason one will usually attempt to obtain a large boundary surface area between the phases involved, what is achieved in a number of very important industrial substance production processes by dispersion of the one phase (or optionally more phases) in the other phase(s) in the form of small bodies (particles, droplets, bubbles), and in such a case for example suspensions (solid parti ⁇ cles in a continuous liquid phase), smokes (solid particles in a
• the substance (or substances) being exchanged between the different phases involved can be identical to the one desired to produce in the production process in question, but it can also be a starting material or turnover substance (such as a nutrient, an energy sub ⁇ strate, or a respiration substance) necessary for the process or a
• waste material e.g. carbon dioxide
• waste material e.g. carbon dioxide
• a typical field of substance production in which the above circum- 2 stances manifest themselves are the biological production processes, in which microorganisms of various kind or single cell or few cell bodies from higher animals or plants are employed for the production of various, more or less specific substances, substance mixtures, or compositions, including the microorganisms or the cells themselves.
• 3Q In the latter case one usually refers to the substance production as a multiplication or propagation of the culture in question, the final purpose of the culture produced being for example inoculation of another medium (e.g. souring of milk or cream), fermentations of various kinds (including e.g.
• a so-called reactor or more specifically 0 a fermentor is used for the production of yeast, the container being supplied a liquid (mainly water) containing or being supplied the nutrients, salts and icronutrients (together designated the substrate) necessary for the yeast, plus a starting amount of the yeast to be produced.
• a liquid mainly water
• the nutrients, salts and icronutrients (together designated the substrate) necessary for the yeast, plus a starting amount of the yeast to be produced.
• the yeast In order that the yeast can be capable to grow and propagate it must be supplied oxygen. (If not, an anaerobic fermentation of the substrate will take place in connection with production of alcohol but resulting in only minor propagation of the yeast).
• the oxygen can be supplied as pure oxygen gas, but since this is uneconomically expensive, atmospheric air (possi ⁇ bly somewhat enriched with oxygen) is in practice most often used, usually being introduced at the bottom part of the fermentor as air bubbles which of themselves, due to the general gravitation and the difference in densities between the bubbles and the surrounding liquid, will ascend through the fermentation liquid. During their ascent a diffusion of the oxygen will take place out of the air bubbles to the surrounding liquid, in which it is dissolved and from where the yeast cells will absorb it during their growth and divi ⁇ sion (propagation).
• Another phenomenon that limits the oxygen transfer rate from the air r bubbles to the fermentation liquid is, as earlier mentioned, contin ⁇ gent on the size of the area of the common boundary surface between the substance exchanging phases, in this case the total surface area of the bubbles.
• contin ⁇ gent on the size of the area of the common boundary surface between the substance exchanging phases, in this case the total surface area of the bubbles.
• the mathematical product of the number of bubbles per unit volume of fermentation liquid and the average volume of the bubbles is usually expressed as the bubble volume percentage of the bubble-containing fermentation liquid and is referred to as the "hold-up value" or 5 simply the "hold-up".
• stirred or back-mix fermentor or reactor type one or more 0 stirring means will be provided in the fermentor. Possibly they may be positioned at different heights in the fermentor, but at least one will usually be located at the fermentor bottom.
• stir ⁇ ring with the stirring means the fermentation liquid will be homoge ⁇ nized in all directions and levels at such powerful stirring that 5 strong turbulence and vertical circulation in the fermentation liquid is caused.
• the other type is characterized by the fact that the fermentation liquid has a predominant mass flow (bulk flow), which essentially has the character of piston or plug flow, through at least one closed or endless cycle (the loop) which is defined by solid physical bounderies such as container, tube and/or hosepipe walls which are connected into an annular system.
• bulk flow essentially has the character of piston or plug flow
• the loop which is defined by solid physical bounderies such as container, tube and/or hosepipe walls which are connected into an annular system.
• mass flow has the character of piston or plug flow does not mean that the flow necessarily has to be laminar, it can very well be turbulent and even with some inner circulation or back-mix, as long as the underlying tendency towards inner backflow in the cycle does not reach the same magnitude as the predominant mass flow in the flow direction of the cycle.
• That the mass flow takes place in a closed or endless cycle means that the prevailing or at least an essential part of the fermenta ⁇ tion liquid at least at one position of the cycle passes through the cross section of the cycle at least twice at this position, before it leaves or is withdrawn from the cycle.
• En route fermentor liquid may well be introduced into or removed from the cycle to some minor extent at one or more positions, and this is so far as it goes the usual practice. The introduction and removal flows procured hereby should just not become dominant compared to the main mass flow in the cycle.
• the mass flow can take place in an essentially horisontal or verti ⁇ cal direction or any direction therebetween, the essentially verti ⁇ cal direction probably being the most common.
• a vertically oriented loop fermentor can be composed of a cylindrical container closed at both ends, in the interior of which a shorter cylindrical tube having a smaller diame ⁇ ter than the container and having both ends open is located coaxial -
• the circulation of the fermentation liquid occurs as a mass flow in one direction within the cylindrical tube and a mass flow in the opposite direction in the annular space between the cylindrical tube and the cylindrical wall of the. container, these mass flows joining each others at the
• the mass flow can be generated by a mechanical impeller, such as a turbine, a • screw, or a propeller, being positioned suitably in the cycle. In practice, however, the mass flow will usually be generated by means
• Loop fermentors (especially those with an inner draft tube in a cylin ⁇ 0 drical container) of various designs have in great numbers been described in the patent literature, being operated both mechanical ⁇ ly, pneumatically or hydraulically or through combinations thereof; reference is made just to for example US 3,910,826, US 3,984,286, US 4,036,699, and DE 2,603,668. 5
• the aeration bubbles can in principle be introduced anywhere in the cycle, but as a consequence of the fact that they usually always have to be withdrawn at the top of the cycle due to the natural tendency of the bubbles to accumulate, coalesce, and separate from the liquid at this place, the introduction of the bubbles will usu ⁇ ally be at the bottom of the cycle.
• this is the case for most draft tube loop fer entors, wherein the air, possibly together with t - supplementary liquid, is supplied as a momentum flow into the lower end of the draft tube.
• 25 tion of surface active substances may have a negative influence on the fermentation, especially the propagation rate.
• 1C accumulates in the upper part of the fermentor through a funnel mounted on the top of the centrifuge.
• the foam is separated into a cell -rich liquid phase and a liquid phase contai ⁇ ning gas, or possibly into a cell -rich liquid phase, a cell depleted liquid phase, and a gas phase, of which at least a part of the
• liquid phase and/or the cell-rich phase is withdrawn from the fermentor.
• the fermentor used according to the EP patent is, howe ⁇ ver, not a loop fermentor but rather a stirred fermentor with complete back-mix.
• the retention time is specified as 8 to 10 hours.
• Minor 5 and small bubbles will, to a higher degree, be carried along in the circulation flow, one cycle passage after the other, and only due to enlargement through bubble coalescence or inward diffusion of carbon dioxide they will gradually reach the bubble size leading to separation uppermost in the cycle.
• Minor and small bubbles are, however, as mentioned earlier, the most effective oxygen transpor ⁇ ters, in as much as they more rapidly release their oxygen to the surrounding liquid. In the loop fermentors hitherto known they are, however, not ideal, since they will be dragged around in the cycle as useless, space-occupying dead volumes after their rapid release of the oxygen.
• the present invention provides a teaching as to how minor and small air bubbles ideal as oxygen transporters can be used in loop fermen ⁇ tors and at the same time having them removed from the circulation at the time, where their oxygen content has been reduced to a level that judged from an oxygen transportation point of view makes them no longer optimal or appropriate.
• the invention thus provides the possibility of fulfilling the oxygen demand of a loop fermentor to a hitherto unattainable degree and thereby obtain a hitherto unattain ⁇ able productivity per unit volume of fermentation liquid.
• the invention provides, however, also productivity advantages when larger air bubbles are used, as the removal of oxygen depleted or oxygen-poor bubbles will be more effective also for such larger bubbles, whereby a greater part of the circulation volume will be available for production, which will increase the fermentor's productivity per unit volume of fermentation liquid.
• the present invention also concerns a loop reactor for performing the said process, which loop reactor comprises at least one loop with a reaction volume, propulsion means for operating the circula ⁇ tion in the loop, and a centrifugal separator, which reactor being characterized in that the centrifugal separator is an integral part of the loop, thus receiving all or essentially all the reactor contents for each cycle passage through the loop, whereby the contents are divided into at least two fractions having different contents of at least two different constituents, and that the centrifugal separator has means for separation of the two fractions, means for passing one of the fractions further on in the loop, and means for draining off the other of said fractions from the loop.
• Figure 1 is a longitudinal sectional view executed through the axis of an embodiment of an inner loop fermentor or reactor according to the invention
• Figure 2 is a cross sectional view of two combined spiral and helical channels in a cyclone separator according to the invention, taken along the line A-A in Figure 1,
• Figure 3 shows a cross section in an enlarged scale of a combined nozzle device for air and liquid introduction into a loop fermentor or reactor according to the invention, taken along the line B-B in Figure 1,
• Figure 4 shows, in approximately the same scale as in Figure 3, a cross section taken along the line C-C through the nozzle device shown in Figure 3,
• Figure 5 represents a longitudinal sectional view executed through the axis of a second embodiment of an inner loop fermentor or reactor according to the invention
• Figure 6 represents a cross sectional view of an inner loop fermen ⁇ tor according to the invention, taken along the line D-D through the embodiment shown in Figure 5,
• Figure 7 represents a longitudinal sectional view executed through the axis of a third embodiment of an inner loop fermentor or reactor according to the invention
• Figure 8 represents a cross sectional view taken along the line F-F through the embodiment of an inner loop fermentor or reactor shown in Figure 7, which cross section shows a helical channel in the cyclone separator as seen from above
• Figure 9 shows a guiding plate in the helical channel shown in Figure 8, as seen from the side,
• Figure 10 represents a longitudinal sectional view executed through the axis of a fourth embodiment of an inner loop fermentor or reactor according to the invention
• Figure 11 represents a cross sectional view taken along the line G-G through the embodiment of the inner loop fermentor shown in Figure 10,
• Figure 12 shows in an enlarged scale a helical channel as seen from above of a cross section taken along the line H-H in the loop fermentor shown in Figure 10,
• Figure 13 shows, in a flat version before being bent to the screw- shape, one of the guiding plates in the helical channel shown in Figure 12,
• Figure 14 shows the screw channel guiding plate shown in Figure 13 as seen from the side after being bent to its screw-shape
• Figure 15 represents a longitudinal section executed through the axis of a fifth embodiment of an inner loop fermentor or reactor according to the invention
• Figure 16 represents a longitudinal section executed through the axis of another embodiment of the inner loop fermentor or reactor shown in figure 15, which embodiment is closed at the bottom and has one or more exits at the top for liberated air or air-mixed liquid,
• Figure 17 represents a longitudinal section executed through the axes of an outer loop fermentor or reactor according to the inven ⁇ tion.
• the embodiment of an inner loop fermentor or reactor according to the invention depicted in Figure 1 in an axially longitudinal sectional view has an outer container wall 8 and an inner container wall 9 which together with the adjacent bottom wall 87 and top wall 88 define an outer, cylindrical-annular reaction or working volume 6 of a fermentor loop.
• An inner cylindrical tube 22 defines, together with the inner container wall 9, the bottom wall 87, and a head cover 89, an inner cylindrical-annular separation volume of the fermentor loop.
• the outer working volume and the inner separation volume are connected at the top via an annular gateway 90, as the inner container wall 9 does not at this place extend all the way up to the top wall 88 of the container.
• the working and the separation volumes are connected via 180° gateways through the inner container wall 9, each of these passages (gateways) having a channel-shaped elongation extending into the outer working volume.
• One of these channel extentions is depicted in the Figure and is established by a vertical curved guiding plate 79, the container bottom wall 87, a lower guiding plate 14, and an upper guiding plate 16.
• Each channel extension is elongated into the inner separation volume, where the one channel extension shown in the figure is defined by the upper guiding plate 16, the lower guiding plate 14, and a vertical curved guiding plate 80.
• the upper guiding plate 16 has a lower introductory edge 416 and an upper terminating edge 216 and the lower guiding plate has a lower introductory edge 414 and an upper terminating edge 214.
• the upper guiding plate 16 and the lower guiding plate 14 are, up to the upper terminating edge 216 of the upper guiding plate, snail- shaped and are turned upwards, so that the channel defined hereby takes the shape of a snail passage, i.e. a spirally and helically shaped channel, the debouchment of which in the inner separation volume is designated 12.
• a similar snail passage (not shown) is located in the space in front of the plane of the paper in the Fi ⁇ gure and has the debouchment 112 shown in the Figure.
• the momentum flow will, however, not only have a radial b velocity but also a tangential velocity which gives rise to a turbulence field created of gyroscopic forces in the annular gateway 90 at the bending 10 of the free end of the inner container wall 9, which turbulence field will reduce the radial velocity of the flow to some extent.
• the liquid flow in the working volume 6 may, depen ⁇ 0 dent on the speed and inclination of the momentum flow, become turbulent, turbulent with rotation about the inner container wall 9, or turbulent with rotation and inner circulation, but regardless of these conditions the overall flow will be downwards and have the character of piston or plug flow.
• the fermentation liquid is led into the openings 11 and 111, respectively, of the snail-shaped channels which lead to the inner separation volume 7.
• this rotation will have 0 such direction that it leads the liquid directly into the openings 11 and 111, respectively.
• the snail-shaped (i.e. spiral and helical) channels will amplify this rotation, and the rotational velocity of the liquid will be increased strongly as a consequence of the gradually decreasing radius of curvature.
• the fermentation liquid will be divided into an outer cylindrical ring-layer consisting of essentially bubble free liquid and cells and an inner layer consisting of air and/or strongly air bubble-containing liquid with essentially unchanged density of cells in the liquid.
• the cylindrical tube 22 serves, in addition to being an outlet means from the fermentor, as a central space-oc ⁇ cupying means in the separation volume 7, so that no region subjec ⁇ ted to a low G.-value and hence a poor separation exists in center of the separation volume.
• the fermentation liquid in the cylindrical ring-passage 2 will, under continued rotational upwards directed movement, be passed up into the upper annular gateway 90, where the liquid will be imparted new increased flow speed or higher pressure by the momentum flow of liquid and torn-out bubbles produced by the nozzle devices 30 and, as described above, be passed 15 into the outer working volume 6 of the fermentor and thereafter continue its flow as described previo ⁇ usly.
• the flow of air and/or strongly air bubble-containing liquid passed into the interior of the cylindrical tube 22 will be led downwards through the tube and via a conduit 49 passed to an outer separator 23 which may be a gravitational separator or a cyclone separator or a centrifuge, in which air and fermentor liquid will be effectively separated.
• an outer separator 23 which may be a gravitational separator or a cyclone separator or a centrifuge, in which air and fermentor liquid will be effectively separated.
• Liberated air 24 will be vented into the atmosphere, possibly after a further purification, while extracted liquid will be led via conduit 25 and possibly drained off via valve 26 or passed on via the valve 126 to the pump 28 which, at a sufficient pump pressure, will return it via conduit 50 to the nozzle devices 30.
• Supplementary liquid containing nutrients, salts, and micro- nutrients necessary for the culture may via the valve 27, the pump 28, and conduit 50 be passed to the nozzle devices 30 for mainte ⁇ nance of the amount of fermentor liquid necessary for
• the embodiment of the loop fermentor or reactor according to the present invention shown in Figure 1 is an inner loop fermentor, i.e. a loop fermentor wherein the one part of the cycle is completely surrounded by the other part of the cycle.
• the inner part of the cycle constitutes an effective cyclone separator while the outer part of the cycle constitutes a reaction volume, in which the uptake and the turnover of oxygen is essentially taking place.
• the separation volume i.e. the cyclone separator
• the two channel elongations will maintain the radial orientation of the liquid, which is partly rendering the level of turbulence low for the benefit of the separation and partly enabling some pre-separation in the reaction volume 6. This renders the use of smaller bubbles and hence higher productivity possible.
• fermentor liquid is exhausted via conduit 49 and possibly drawn off via the valve 26.
• this off-drawing could constitute the flow of product, but in addition a direct outlet for drawing off product, both at continous and batch operations, may be provided in the fermentor.
• Figure 2 shows a cross sectional view taken along the line A-A in the loop fermentor according to the present invention shown in Figure 1.
• the bottom part of the fermentor is viewed from above.
• 8 Indicates the outer container wall of the fermentor
• 9 indicates the inner container wall
• 22 indicates the inner cylin- drical tube
• 14 and 114 respectively, indicate the lower guiding plates
• 16 and 116 respectively
• the upper guiding plates 79 and 179, respectively
• 80 and 180 designate the inner guiding plates of the two spiral- and helical-shaped channels leading from the outer working volume to the inner separation volume of the fermentor
• 416 and 516 respectively, indicate the upper, terminating edges of the upper plates 16 and 116, respectively.
• Figure 3 shows a section through a nozzle device for combined intro- duction of air and liquid, the latter or both pressurized, said sec ⁇ tion being executed along the line B-B through the nozzle device 30 shown in Figure 1.
• the nozzle device has an inner, tubular chamber 35 for introduction of liquid and an outer chamber 37 for introduc ⁇ tion of air.
• 40 Indicates a cross wall in the slit-shaped outlet nozzle 36 of the liquid chamber for keeping together the walls of the outlet nozzle when the pressure is high.
• 39 Indicates a crest- shaped edge for limitation of the turbulence in the liquid surroun ⁇ ding the nozzle device 30.
• nozzles are slit-shaped and essentially span all across the passage 2 saves energy in the bubble formation and gives a very uniform spreading of the bubbles in the liquid.
• Figure 4 shows a cross section taken along the line C-C through the nozzle device shown in Figure 3.
• 41 Indicates the outlet slit of the liquid chamber, 37 indicates the air chamber, and 40 indicates cross walls for keeping together the outlet slit of the liquid chamber.
• Figure 5 represents a longitudinal sectional view executed through the axis of a second embodiment of an inner loop fermentor according to the present invention.
• This fermentor has spiral-shaped channels 44 that are not helical and the outlet 22a from the inner centrifu ⁇ gal separator of the fermentor is placed at the upper end of the separator, so that outlet of air and/or air bubble-rich liquid separated in the centrifugal separator takes place in an upward direction.
• the outlet conduit can in its initial part be made conical as the fermentor top in Figure 16, and a distinct, preferab ⁇ ly annular, return conduit for liquid to the reaction volume 6 may be employed.
• the spiral channels 44 at the bottom of the fermentor are defined by askew positioned plates, the bottom wall 87 of the fermentor, and a ring-cone at the outside of the foot of the inner container wall 9.
• a conical elevation placed centrally on the bottom plate 87 inside the separation volume 7 forces the fermentation liquid passed in through the spiral channels, upwards around the inner circular upper edge 48 of the spiral channels 44, so that the liquid is given an upwards directed rotation in the separation chamber 7.
• a cyclone separation effect similar to the one referred to under Figure 1 is achieved.
• the reference numbers 52 and 53 indicate two rims of flow regulating guiding plates placed on the outer container wall 8, which guiding plates are directed obliquely upwards to the right and upwards to the left, respectively, and, in the case of tangential rotation in the reaction volume 6, have the purpose of contributing to the creation and/or maintenance of relatively weak radial whirls in the downgoing liquid flow in the outer reaction volume, what will counteract separating out of bubbles in the reaction volume. Plates could be mounted obliquely in other ways in the reaction volume 6 and produce the same result.
• the plates 52 and 53 shown are examples of good positioning.
• Other reference numbers in Figure 5 have the same meaning as mentioned in Figure 1.
• Figure 6 shows a cross sectional view taken along the line D-D through the loop fermentor shown in Figure 5.
• the Figure thus shows the bottom part of the loop fermentor shown in Figure 5 viewed from above.
• 8 Indicates the cylindrical outer wall of the loop fermentor and 9 indicates the cylindrical inner wall of the fermentor.
• 56 Designates the lower outer edge of the ring-cone placed around the inner cylindrical wall, 44 designates a spiral channel, 45 the entrance of this channel, and 46 its debouchment into the inner separation volume, whilst 55 indicates a side wall in the spiral channel .
• Figure 7 shows a longitudinal sectional view executed through the axis of a third embodiment of an inner loop fermentor according to the present invention.
• This fermentor has connection channels 58 between the outer reaction volume 6 and the inner separation volume 7, which channels 58 are helical but not spiral-shaped.
• 60 indicates the introductory edge of a screw channel guiding plate and 62 the terminating edge of a screw channel guiding plate.
• 57 Indicates the lower free edge of the inner cylindrical container wall 9.
• Other references have the same meaning as in Figure 1.
• the fermentor circuit can be provided with one or more rims of obliquely mounted guiding plates as mentioned in connection with Figure 5.
• connection channels 58 are surrounded by the inner contai ⁇ ner wall 9 means that these channels, in contrast to the spiral channels in Figure 5, are placed over the loop bottom, where the liquid attains its upward velocity.
• connection channels 58 can dampen the turbulences created at the loop bottom, thereby improving the subsequent separation.
• the tall design of this third embodiment is advantageous for proces ⁇ ses, where pronounced tendency to coalescence of bubbles or some other reason dictates the use of relatively large bubbles. Large bubbles ascend faster, and since the bubbles are to be brought downwards by the liquid in the outer reaction volume 6, the height is advantageous by increasing the downflow speed of the liquid in the reaction volume.
• Figure 8 shows a cross sectional view taken along the line F-F through the loop fermentor shown in figure 7, but only the inner part delimited by the inner, cylindrical wall 9 of the fermentor. 22 • Indicates the inner cylindrical tube, 59 indicates a screw channel guiding plate or ascent plate, 60 indicates the introductory edge of a screw channel guiding plate, 61 indicates the inner edge of a screw channel guiding plate, 62 indicates the terminating edge of a screw channel guiding plate, and 63 indicates the outer edge of a screw channel guiding plate.
• Figure 9 shows one of the screw channel guiding plates of Figure 8 shown from the side. 60, 61, 62, And 63 indicate the same as in Figure 8.
• the plate is twisted out of plane but is not curved, since this is not necessary because the embodiment of the loop fermentor according to the present invention shown in Figure 7 does not contain means that will brake the tangential rotation in the outer cycle, which means that the fermentation liquid will be in rotational motion before being introduced into the screw-shaped channels leading to the inner separation chamber.
• the plate is twisted out of plane in order to secure essentially uniform angular velocity in the radial dimension of the separation volume 7. This minimizes the level of turbulence in the separation volume, which improves the separation of bubbles from the liquid.
• FIG 10 shows a longitudinal sectional view executed through the axis of a fourth embodiment of an inner loop fermentor according to the present invention.
• This fermentor has, in addition to nozzle devices 30 for the introduction of gaseous material 64 and liquid 50, an extra set of inlet devices 65a and 65b for introduction of air 29 and liquid 50.
• the fermentor has a rim of momentum exchange tubes 66a and 66b positioned in line with the debouchments of the extra liquid inlet devices, while the upper part of the reaction volume 6 is otherwise essentially blocked by a plate 69, so that all or nearly all downward flow will have to pass through the momentum exchange tubes 66a and 66b.
• the liquid jet from inlet device 65a will tear away any gas accumulation at the top of the fermentor.
• the liquid nozzle 91 in the inlet devices 65 can be essentially circular, oblong or star-shaped, just as there can be more than one nozzle in each inlet device.
• the momentum exchange tubes are parallel to the axis of the fermentor, whereby the rotation of the fermentation liquid around the axis after its passage through the inner centrifu ⁇ gal separator is braked by the momentum exchange tubes in the upper part of the reaction volume.
• the initial part of the helical channels 58 between the reaction volume 6 and the interior of the separation volume 7 is made parallel to the axis of the fermentor.
• the momentum exchange tubes 66a and 66b do not, however, have to be _ parallel to the axis of the fermentor, and the extra inlet devices for liquid and air can be used without the momentum exchange tubes 66a and 66b and/or the blocking plate 69 positioned uppermost in the reaction volume 6.
• the momentum exchange tube 66a is provided with a diffuser 67, which
• the momentum exchange tube 66b (which is not provided with a diffu ⁇ ser) and the blocking plate 69 have the same purpose. 0
• annular passage 90 is shown with a diffuser 68 that causes a pressure rise in the liquid flowing through the passage 90, which contributes advantageously to the flow of the liquid from the inner separation chamber 7 to the outer reaction volume 6.
• liquid 50 from the pump 28 (not shown) or a pump parallel therewith can be introduced, as can e.g. NH 3 , 0 2 and/or CH.-containing gas, e.g. natural gas or biogas, through conduit 64.
• CH.-containing gas e.g. natural gas or biogas
• That the inlet means 29 for air are placed after the nozzle devices 30 in the loop means that the gas from conduit 64 can be comminuted into finer bubbles than the air comminuted into bubbles at the inlet devices 65a and 65b without increasing the risk of coalescence of _ c air bubbles with bubbles of gas from conduit 64. This allows for higher exploitation of the typically more expensive gasses from conduit 64.
• the inner container wall 9 is shown provided with an outwards bent free end 43, cross-sectionally shaped like a pear, while 58, 60, and 62 as previously indicate screw-shaped channels from the outer to the inner cycle of the loop fermentor, the introductory edge of a screw channel guiding plate (ascent plate), and the terminating edge of a screw channel guiding plate (ascent plate), respectively.
• Figure 11 shows a cross sectional view taken along the line G-G through the loop fermentor shown in Figure 10 and thus shows the blocking plate 69 and the momentum exchange tubes 66 (66a and 66b) seen from above.
• the reference numbers 8, 9, and 21 have the same meaning as previously stated.
• Figure 12 shows a cross sectional view taken along the line H-H through the loop fermentor shown in Figure 10, but only the inner part laying inside the limitation defined by the inner container wall 9.
• 22 Indicates the inner cylindrical tube
• 59 indicates the guiding plate (the ascent plate) in a screw-shaped channel between the outer reaction volume and the inner separation volume
• 60 indicates the introductory edge of a guiding plate (ascent plate)
• 61 indicates the inner edge
• 62 indicates the terminating edge
• 63 indicates the outer edge of such a plate.
• 70 Indicates a corner between a terminating edge and an outer edge of a guiding plate.
• Figure 13 shows a screw channel guiding plate according to Figure
• Figure 14 shows the screw channel guiding plate from Figure 13, seen from the side after being bent for use in the screw-shaped channel in the loop fermentor in Figure 10.
• the plate is bent in a plane- circular manner, which is sufficient to achieve good functionality.
• the reference numbers 60, 59, and 70 have the same meaning as in figure 12, and the arrow 33 indicates the axial direction of the loop fermentor, i.e. typically upwards.
• Figure 15 shows a longitudinal section executed through the axis of a fifth embodiment of an inner loop fermentor according to the present invention.
• the rotation in the inner separation chamber 7 can be produced by spiral channels, e.g. as shown in Figure 5.
• screw channels can be provided in the interior of the separation chamber 7, possibly positioned higher than in figure 7 and figure 10.
• the upper part 71 of the fermentor gives rise to a more complete separation, so that less liquid leaves the fermentor through the outlet conduit 22 in connection with the centrifugal separation.
• 72 indicates an upper annular partition between the upper part 71 of the fermentor and the reaction volume 6, between which there is passage via the slit 73 which can be either annular or be constitu ⁇ ted of tubes that may act as momentum exchange tubes if essentially downwards directed or obliquely tangential-downwards directed liquid nozzles are placed in or above them.
• Inlet means for air and liquid are not shown in the upper part or elsewhere, but such will at most applications be provided and can be of the same character as mentio ⁇ ned earlier in connection with the various Figures.
• Figure 16 shows an embodiment which bears strong resemblance to the one shown in Figure 15, but with the difference, however, that there is no central, cylindrical tube in the interior of the separation volume 7 and that separated air and/or air-containing liquid as a consequence thereof is passed upwards out of the fermentor via the tube 22a. Apart from this deviation, what is mentioned above in connection with Figure 15 is otherwise valid also for the embodiment shown in Figure 16.
• Figure 17 shows a longitudinal section executed through the axes of an outer loop fermentor according to the present invention. That the fermentor is an outer loop fermentor means that neither the ascen ⁇ ding nor the descending part of the cycle is surrounded by the other part of the cycle.
• the fermentor shown has a working volume 6 which is defined in the vertical direction by a cylindrical container 8a-8a, below by a bottom wall 87, and above by a top plate 72a.
• the c separation volume 7 is defined by another cylindrical container surface 8b-8b which at the one side adjoins the cylindrical contai ⁇ ner surface 8a, below by the bottom wall 87, and above by a cylin ⁇ drical ring-plate 72b.
• the upper part 71 of the separation chamber 7 is essentially shaped as the upper part of the separation chamber 7
• the vertical side wall 74 of the upper part is, however, not rotationally symmetrical but has a spiral shape which increases from the minimal diameter a to the maximal diameter b.
• the upper space 71 is connected with the reac-
• one or more nozzle devices may be mounted for the introduction of a flow of liquid and air bubbles for hydro- pneumatic operation of the circulation in the fermentor.
• the loop fermentor will in other 0 respects function as the inner loop fermentors described above. An effective removal of introduced air bubbles will thus, for ewery passage of the cycle, take place in the cyclone separation chamber 71 or chambers 7 and 71.
• any of the embodiments in Figures 1, 5, 7, 10, and 15 can be trans ⁇ formed into outer loops.
• Comminution into small bubbles of introduced gas can be effected in r two ways, viz.: the gas can be passed through small openings into rapidly by-passing liquid, and bubbles already formed can be commi ⁇ nuted by strong velocity gradients in the liquid around the bubbles.
• the latter method may also be used on bubbles of gas which have not been introduced into the reactor or on bubbles which after introduc- 10 tion and comminution have coalesced.
• the gas should preferably be introduced to the liquid leaving the separator before this liquid under deceleration re-attains the higher pressure in the working
• Strong velocity gradients in the liquid around introduced gas can be created by introducing the gas in immediate connection with one or more nozzles in which liquid is having a pump pressure transformed Matt_ into liquid velocity. If gas introducing means are mounted around such liquid nozzles, then it is also achieved that the gas is being introduced into rapidly flowing liquid.
• both the liquid pump pressure and the width of the nozzles are of importance.
• the debouchments of nozzles for this purpose are either circular or short slit-shaped 5 (example: Bayer AG's slit-shaped ejectors for aeration in water purification plants).
• nozzles having round or short-slit- shaped debouchments would have to be used in a large number, which implies a considerable construction cost. It is better to use nozzles having long-slit-shaped debouchments, which is naturally possible in a loop reactor operated at low bubble coalescence rate, 5 in as much as the bubbles will then only have to be formed and delivered into the liquid which, due to the circulation of reactor contents in the reaction loop, is passing by the nozzles. This is in contrast to other reactors, in which larger liquid nozzles of more rounded shape are used for the production of liquid turbulence far
• centrifugal fields both in the reac ⁇ tion volume and in the centrifugal separator of the loop.
• the working volume is provided a radial dimension so large that the bubbles can obtain a fairly high and thus "k"-increasing radial velocity without this resulting in excessive separation of bubbles already in the working volume, whilst the centrifugal separator provides such a high proportion between the angular velocity of the
• the above can also be said almost word-for-word, when the working volume of the loop essential ⁇ ly consists of an axial continuation of the centrifugal separator. If, on the contrary, the centrifugal separator essentially is an axial continuation of the working volume, then the momentum transfer into rotation of the liquid in the working volume will be determined by the cross sectional area of the return conduit and how far from the center-axis of the working volume the return takes place.
• a particular case is when the reactor is being supplied one or more relatively expensive gaseous substances like e.g. CH., 0 2 , and NH 3 which should be exploited nearly 100% in a good reactor and also a less expensive substance like e.g. atmospheric air which due to its mixed composition cannot be expected to be fully exploited.
• the expensive gases as very small bubbles (e.g. natural gas or biogas) followed further on in the loop by the less expensive gas in the form of larger bubbles.
• the expensive gases can be exploited to a higher degree, while the less expensive gas during its removal will only entrain remnants of the expensive gases to a minimum degree.
• methane-containing gas e.g. natural gas or biogas
• NH- nitrogen source or supplement
• purified 0 2 e.g. of industrial quality
• the explosion pressure relief means may be placed in subterranean
• a possible burning of released gas can thus be turned into a hazard- less event by the present invention without any need for repairs regarding e.g. blast caps and without any risk of infection into the present invention
• valves can be provided with actuators (it may e.g. be solenoid valves), which are actuating opening and closure of the valves at preset pressure limits.
• That cultivation can be carried out at elevated pressure means that the increased productivity attached therewith can be achieved also in reactors, in which there is a risk of occurrence of inflammable exhaust gases.

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• 1989
  • 1989-12-08 DK DK421689A patent/DK421689D0/da not_active Application Discontinuation
• 1990
  • 1990-12-10 WO PCT/DK1990/000324 patent/WO1991009111A1/en active IP Right Grant
  • 1990-12-10 DK DK91900741T patent/DK0510010T3/da active
  • 1990-12-10 AT AT91900741T patent/ATE184643T1/de not_active IP Right Cessation
  • 1990-12-10 AU AU69195/91A patent/AU6919591A/en not_active Abandoned
  • 1990-12-10 EP EP91900741A patent/EP0510010B1/en not_active Expired - Lifetime
  • 1990-12-10 DE DE69033290T patent/DE69033290T2/de not_active Expired - Fee Related
  • 1990-12-10 ES ES91900741T patent/ES2138957T3/es not_active Expired - Lifetime
• 1992
  • 1992-06-04 DK DK074992A patent/DK74992A/da not_active Application Discontinuation
  • 1992-06-05 NO NO922230A patent/NO307894B1/no unknown

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