DK168712B1 - Process for implementing a chemical, biochemical or biological reaction or production during which it is desired to separate off a heavy phase, and a reactor for implementing the process - Google Patents

Description

DK 168712 B1

Process for carrying out a chemical, biochemical or biological reaction or production during which a heavy phase is desired to be separated and a reactor for carrying out the process.

In a variety of metabolic processes or fabric production processes of different kinds, there is an exchange of 5 substances between immiscible phases, e.g. solid / liquid phases, liquid / liquid phases, gas / liquid phases, gas / liquid / solid phases or other combination, e.g. with several different phases of the same species in combination with one or more phases of another species or species. One or more of the immiscible phases will normally be fed continuously to the reactor (e.g., air to aerate liquid in a bioreactor) or be sequentially generated therein (e.g., bubbles of biogas in an anaerobic degradation fermentor). Separation of one or more of the immiscible phases and discharge of the separated phase can be decisive for the reaction and / or production and, especially at large reactors, may be the rate limiting factor for the reaction or production, such as to understand faster and / or more thorough separation of a phase and removing it may allow for faster turnover or production. The situation is that the greater the overall interface between immiscible phases between which substances must be exchanged, the faster this exchange takes place and the faster the reaction / production in the reactor can take place. However, an increase of this interface area must typically be achieved through a comminution of bodies (bubbles, droplets or particles) of one phase into another, which inhibits the separation of one phase in a separator. Thus, whether outside separation is the rate limiting factor in the overall turnover / production is first and foremost a question of whether the comminuted phase is so comminuted that this is to a limited extent inhibiting the output separation.

Thus, with a given design of reactor and separator, there is a limit to how much comminution of a phase can raise the rate of turnover / production. If the phase is further decomposed, the turnover / production goes from being limited by the metabolism between phases to being limited by the exchange rate of a phase, which is in practice the rate of separation of that phase. Further comminution of phase will inhibit seed separation and thus reduce the rate of turnover / production. The only way forward to even higher turnover / production speed would then be to change the design of the reactor and / or separator so that faster separation of a very finely divided phase can be achieved. It is furthermore the case that the comminution of phase itself is rather energy intensive. Therefore, increased turnover / production speed is not only a matter of improved seed separation; it is also a matter of limiting it by virtue of widespread comminution of phase high operating costs to the reactor. This must also be achieved through the design of the reactor / separator.

A loop reactor is a reactor in which there is one wall path circulating path for reactor contents of at least one phase (there may be other phases which either do not participate in the circulation or follow it only in part of the circulation path) and in which this circulation of reactor contents constitutes an overall flow thereof, so as to understand that internal back-mixing of this reactor contents takes place at most as a subordinate phenomenon. This over-flow of the circulation stream causes this reactor content to flow in somewhat near plug flow through the circulation path.

The circulation path will most often consist of a single loop, the reaction loop. However, a loop can be split longitudinally into a portion of its length, and then several parallel coupled reaction loops are obtained. One way of doing this in an inner loop reactor is to equip an outer reactor shell with multiple, parallel, inner loop tubes (draft tubes). The flow of circulation through the inner tubes is then substantially the same in the various tubes. thus maintaining the overall piston flow which makes a reactor a loop reactor, a structure which has been used in water purification reactors.

In the following, loop reactors with only one reaction loop and loop reactors with multiple parallel reaction loops will be referred to under one as "loop reactors", and reaction loops will be referred to as "a reaction loop" and "the reaction loop" whereby will be considered the total reaction circuit, regardless of whether this part of its length may be divided into several parallel reaction loops For each circulation of reactor contents through a reaction of a loop reactor, this reactor content is said to have performed a circuit passage.

Examples of non-loop reactors include agitated reactors and bar column reactors. In both of these types, internal backbone predominates over any circulation flow. There may well still be a circulation path delimited by walls, since a stirred reactor or bubble column can be well equipped with e.g. a loop for passing a small current past a measuring instrument, a cooling loop or a separator loop. Such loops do not make a stirred reactor or bubble column reactor a loop reactor, unless the flow through the loop becomes so strong that this flow also takes the form of piston flow within the reactor itself. The boundary assumes piston flow within the reaction space of the reactor and at this boundary is distinguished between loop reactors 5 (e.g. stirred types and bubble columns) with loop outlets and loop reactors on the other.

The difference is substantial, with internal back mixing serving to smooth internal inhomogeneities in the contents of the reactor, whereas, on the contrary, piston flow typically leads to the formation of such internal inhomogeneities (for example, substrate may be added at one point in the loop and used during further circulation; inhomogeneous substrate content through the loop). Thus, the difference between backmix reactors and loop reactors is a process difference and not simply a matter of whether a reactor has some loop.

It is known from US Patent No. 4704363 to incorporate a "shear force" separator into the reaction loop of a loop reactor to reduce, through "shear force," the viscosity of a heterogeneous liquid, thereby allowing gas bubbles to move out of the liquid more easily. This is done according to US 4704363 by ordinary gravity 15 From US Patent No. 4148691 and from DE-A-3331993 it is known to extract a partial flow of liquid with bubbles from a reaction of a loop reactor and to separate bubbles from the liquid in a separator in an outer separation loop. This separator is not only outer in a geometric sense; it is external to the reaction loop in the loop reactor, with the result that the circulation of liquid and bubbles can continue in the reaction loop, even if the withdrawal of liquid and bubbles for the separator is stopped. Thus, in US 4148691 and DE 20 3331993, the separator is not integrated into the reaction loop; this is unlike the separator in US 4704363.

In US 4148691, the bubbles are separated from the liquid in the separator by ordinary gravity, after which the separated bubbles, now in the form of a foam, are broken into a centrifugally acting bubble breaker. The fact that just a centrifugally acting bubble breaker has been chosen is of no particular importance in US 4148691, and the bubble breaker has also not participated in the actual separation of bubbles from the liquid in the separator. This is evident from the fact that in the separator there is no device for conveying liquid to the bubble breaker; gas, on the other hand, can only escape through it.

In contrast, in DE 3331993 a centrifugal separator, more specifically a cyclone, is used to separate bubbles from the liquid in the separator loop. The purpose of using a centrifugal separator for this purpose is not to increase the reactor's productivity, but to prevent bubbles from acting as an actual foam. Thus, the use of a cyclone in DE 3331993 alone serves to overflow the bubble breaker used in US 4148691.

Further, from DE 3331993, it is known to direct a residual portion of the bubble stream through a bubble column reactor to an outer centrifugal separator. The discharge of the residual flow of bobbies occurs with a discharge of liquid, and it is this last that is the desired discharge. The role of the separator is to remove residual bubbles from the liquid stream alone, the main flow of bubbles is stated in DE 3331993 to move up to the liquid surface in the bubble column reactor. Thus, the separator serves neither to increase the bubbling rate in the reactor nor to prevent foaming; the 35 alone serves to achieve a more complete removal of bubbles from the liquid to be discharged.

EP patent specification No. 51151 is known to incorporate a centrifugal separator into the interior of a reactor. However, although the separator is geometrically built into the interior of the reactor, it is not part of any reaction circuit in the reactor. The reactor will still be able to operate even if no liquid is withdrawn into the separator; this will then simply be a gas outlet from the reactor. Thus, the separator is not part of an actual reaction loop in the reactor, which is also evident from the fact that the liquid retention time in the reactor reaction space in EP 51151 is set to approx. 8-10 hours, unlike the usual circulation times in loop reactors of about 20-120 seconds. The reactor in EP 51151 is a stirred reactor (which is a turbine for stirring) and not a loop reactor. The separator in EP51151 is a centrifuge because its purpose is primarily to separate cells from the liquid in the reactor. This is a well-known unit operation, which usually belongs to what is called purification processes. Thus, the idea of EP 51151 is to introduce a purification process into the reactor while maintaining sterility. EP 51151 mentions a single situation where this can lead to increased productivity, namely if the turnover / production is limited by low cell density or by product inhibition. Then a replacement of the fluid around the cells, established by centrifuge, leading to increased productivity. The limiting factor here will not be the exchange of substance between phases, but the reaction itself in the cells. Thus, the situation in EP 51151 is different from that of the present invention, cf. the following.

The present invention provides an indication of how to obtain a good separation of a heavy, 5-part phase from the contents of a reactor and thus a high productivity, how to have an advantageous operating economy in the reactor and how to obtain filamentous particles withheld from a liquid to be directed from a reactor's reaction space.

Such retention of filamentous particles from a liquid to be dispensed can be especially advantageous if the reactor is desired to be operated as a so-called nozzle reactor, where the discharged liquid is pumped up into a pump and fed back to the reactor's reaction space through nozzles. wherein pressure is converted to velocity. In pumps and nozzles, it may be inconvenient to have a high density of filamentous particles in the liquid, as the threads will then tend to grip each other. This can be unlucky spleen. the threads themselves (these may be microorganisms that are not wanted to be injured); this can lead to pump / nozzle clogging, and it will typically increase the viscosity of the pumped fluid at least, which increases the energy cost of pumping.

Also, having the filamentous particles retained in the reactor reaction space can be advantageous by enabling the exchange of the fluid around the filaments, quite similar to the advantage of being able to exchange liquid around cells in EP 51151. However, the agents for this are others of the present invention, and the In the present invention, it will typically be possible to replace the liquid much faster than in EP 51151.

A good separation of finely divided phase is partly a matter of speed in the output separation, that is, the separated amount of 20 phase per unit. time unit, and partly a matter of obtaining uniform residence time for this phase in the reactor. The purpose of the finely divided phase is, as discussed on page 1, to participate in / carry out the exchange of substance with the surrounding phase, and this is a process which decreases in speed, the older the phase bubble / droplet / particle. Uniform residence time is then advantageous by providing the best combination of partly utilizing the phase's capacity for metabolism and partly the speed of metabolism per unit. surface area of the phase. This provides the best combination of high productivity and good operating economy.

25

The above is achieved by the process of the invention for carrying out a chemical, biochemical or biological reaction or production in a loop reactor into which immiscible phases are introduced or produced, which is similar to a particular process of WO 91/09111 as far as such that all or substantially all of the reactor contents of each circuit passage through the reaction loop are fed into one end of a centrifugal separator, wherein the reactor contents, further moving toward the other end of the centrifugal separator, are divided into at least two fractions having different contents of at least two immiscible phases. At the other end of the centrifugal separator, the two fractions are physically separated from each other, whereupon the outer heavy fraction is directed from the reaction loop of the loop reactor, while the inner light fraction is further advanced into the reaction loop. That it is the outer fraction that is led from the loop, while the inner one is passed on in this, is new in relation to WO 91/09111.

35 The benefits of productivity and economy are achieved through the combination of 4 conditions: that it is a loop reactor, that all or substantially all of the reactor content is passed through a separator for each circulation of the content through the reaction loop, that this separator is a centrifugal separator and the reactor contents move together from one end of the separator to the other during the separation. The advantage of the latter, the longitudinal movement through the separator during the separation process, is that this movement results in a reduction of the turbulence level in the reactor content during the separation, and a lower turbulence level gives faster and more complete separation.

The present invention further relates to a loop reactor for carrying out the process which comprises a reaction loop with a reaction volume and drive means for operating the circulation of reactor contents in the reaction loop and a centrifugal separator (optionally one per reaction loop in a reaction loop). multiple reactor reactor) forming an integral part of the reaction loop, which centrifugal separator is supplied at one end all or substantially all of the reactor contents for each passage thereof through the reaction loop, whereby the reactor contents of the centrifugal separator are divided into at least two fractions having different contents of at least two different components and each centrifugal separator at its other end has means for separating the two fractions, means for furthering the inner fraction in the reaction loop and means for dissipating the outer fraction from the reaction loop. The loop or loops of the loop reactor can be of any type, including inner or outer loops.

The invention relates to the dissipation or continuation of fractions from the centrifugal separator and thus does not consider how the centrifugal force-creating rotation of reactor contents in the centrifugal separator is established. The rotation can be created by tangential force transfer from one or more mechanical means in the centrifugal separator. These may be rotating means, whereby the centrifuge separator may be given the character of a centrifuge. The rotation of reactor contents can also be created by the centrifugal separator feed means or means being a tangential direction or channels relative to the axis of rotation of the centrifugal separator such that the entrained reactor content already has a tangential velocity component at its feed, whereby the centrifugal pair gets the character of a cyclone separator. In the case of tangentially oriented conduit channels, these may optionally be helical or helical or a combination thereof, as described in WO 91/09111.

A particular embodiment of the invention consists in extracting from the reactor loop also a central fraction from the centrifugal separator or from a centrifugal separator following in the loop. The central fraction may e.g. consist of or contain gas freeze, possibly from an aerated fermentation process. More generally, it may be a process in which a reactive toxin receives reactant (s), substrate (s) or other nutrient from and / or delivers product (s) to two other phases, one of a higher density than the reactive tose and one of a lower density than the reactive tose.

It may also be the case that filamentous, possibly branched filamentous, particles are suspended in a heavy phase, e.g. an aqueous phase or other liquid in which a lighter phase (e.g., bubbles or a light liquid in droplet form) is also suspended. If part or all of the filamentous particles are retained in the reaction loop during a separation and derivation from the reaction loop of part of the heavy phase, it will be advantageous to first separate at relatively low G-value so that the filamentous particles in a relatively high degree of the lighter shaft is drawn inward toward the axis of rotation of the centrifugal separator, to peel off the outer and highly straight particle-poor fraction and then separate further at a higher G value, so that the lighter phase draws the particles further inward toward the axis of rotation of the centrifugal separator. finally, to deprive the inner faction. This reduces the amount of filamentous particles which are led from the reaction loop by the two fractions considered. The two situations mentioned above can be realized in one and the same process.

30

The invention can be carried out such that part or all of the dissolved outer fraction is returned to the reactor loop. If part of the derived outer fraction is returned, this part may be taken out as a new fraction in an additional separator to divide it. separated, outer fraction in more than one new fraction. This may be a return to the reactor of stranded, filamentous particles or reconditioning of (renewal of reactant or substrate or other nourishment or removal of product from) a phase of the derived outer fraction. Henred retains the filamentous particles or the mentioned toss for use in the reactor.

The reactor content of the reactor may be gaseous or liquid and may then be applied to a pressure increase in a pump and, when returned into the reactor loop, be passed through pressure nozzles. Henred achieves an acceleration of the recirculated gas or liquid, which can either by torque transfer contribute to or be the only means of driving the circulation of reactor contents in the reactor loop, and partly disperse a phase of the recirculated reactor content into another phase of the reactor loop. one, whereby a large contact surface between the two phases is obtained for the benefit of the process. Likewise, one or more jets of back-reactor contents can disperse a residual, optionally allowed phase, into another phase in the reactor loop. For example, be it the discharge of entrained air into bubbles in reactor fluid. In all cases, a reduction in the concentration of any filamentous particles would be an advantage in lowering the viscosity of the back-pumped portion or the whole of the derived outer fraction. Incidentally, it is known to drive circulation of reactor contents in a loop by pumping fluid through pressure drop nozzles into the loop, and it is known to allow entrained liquid to dispense supplied air to bubbles.

DK 168712 B1 5

Part or all of the inner fraction derived from the reactor loop as described above in one embodiment can be returned to the loop, and all of the above described for the return of an outer fraction could then apply quite similarly to the return of part of the reactor loop. or the entire inner fraction.

A particular embodiment is that the reactor loop is redirected to both part or all of the outer fraction and part or all of the interior and that these are mixed prior to feeding to a pump from which the mixture is returned to the reactor loop. one. In addition to using only one pump, this is particularly advantageous in a situation where filamentous particles have been concentrated in the inner fraction. This may be an aerobic fermentation with filamentous microorganisms in the reactor liquid and with the internal fraction consisting of a quantity of liquid, with increased content of the filamentous microorganisms, dissipated together with spent air. After removing the spent air from the entrained liquid in an additional separator, which may also be a centrifugal separator, mixing an outer fraction with reduced content of the filamentous microorganisms will be advantageous in lowering the viscosity of the liquid from the inner fraction. can be pumped more easily without damage to the filamentous microorganisms.

15

Another embodiment with the back-guiding of parts or assemblies of both outer and inner fractions is to back these parts or assemblies separately but in close proximity to each other. This is advantageous if one part or whole of a fraction can withstand pumping and passage of a pressure drop nozzle better than the mixture of the two and if mixing of the two parts or whole is desired at the latest in connection with their return to the reactor loop. This may e.g. may be the case with a fermentation with filamentous microorganisms derived in high concentration in one liquid portion or whole and in low concentration in the other liquid portion or whole. The low concentration portion or unit may then be pumped and passed through pressure folding nozzles located in, around or in the immediate vicinity of inlet ports for the second, possibly weaker pumped, portion or unit, thereby mixing it with each other and with the surrounding reactor fluid, optionally, as well as expelling to bubbles of air or other gas, also supplied in, around or in the immediate vicinity of the pressure sensing nozzles.

A third embodiment of relaying parts or whole of both outer and inner fraction is to pump one part or whole and then supply it as a driving fluid to one or more ejectors which are also fed to the other part or whole, as thus in the ejector or ejectors. being pumped by the driving fluid. Hereby, the second part 30 or whole does not need to be pumped into a mechanical pump to be returned to the reactor loop. This is extra gentle for the second part or whole, especially for filamentous microorganisms therein. The ejector or ejectors may constitute the reactor fluid orifice means or, as in the previous embodiment, other material may be introduced into, around, or in close proximity to the ejector's orifice into the reactor loop for good dispersion or other admixture of this material into the reactor's other contents. .

35

The invention will now be described in more detail with reference to the drawings, in which:

Fig. 1 shows an axial longitudinal section through an embodiment of an outer loop reactor or fermentor according to the invention; Fig. 2 shows an axial longitudinal section through an embodiment of an internal loop reactor or fermentor according to the invention; Fig. 3 shows a cross section taken along line AA through the embodiment of an internal loop reactor 45 or fermentor shown in Figure 2, showing a cross-section of a helix of screws in the cyclone separator seen from above in enlarged version, Figure 4 shows a guide plate in the helix of helix shown in Figure 3 seen from the side.

In Figure 1, 6 represents a reaction volume in the reactor loop, which reaction volume is defined in a vertical direction by a container wall 8, which may be cylindrical, below a bottom wall 87 and at the top of a top plate 72. The bottom of the reaction volume 6 extends. a channel 5 which can radially or tangentially open from the reaction volume 6, tangentially and behind the plane of the figure (longitudinal section) into a separation volume 7, which is vertically bounded by a cylindrical container wall 9 and below the bottom wall 87.1 the lower part of the separation volume 7, a central cylinder wall 22 with upper cone 47 serves to take up space centrally in the separation volume, so that the rotation of reactor contents in the separation volume 7, which is thus a centrifugal separator, more specifically a cyclone separator, takes place in its lower part about the central cylinder wall and its upper cone. 12, the orifice opening from channel 5 into the separation volume 7, and 14 is a spindle (= screwed) wall extending from the bottom wall 87 10 and 360 arc degrees around the cylinder wall 22 and up to the edge 216 which coincides with the upper edge of the opening 12. Separation volume 7 is terminated upwardly by the cylindrical partition 51, which together with the container wall 9 delimits an outer, cylindrical shell-shaped conduit 16. The conduit 16 leads an outer fraction of reactor contents to a collection manifold 17 which forms an annular cross-section of the actuator. continued in the direction of rotation, and which culminates in a tangential discharge pipe 99 in the same manner as 15 at a centrifugal pump. The cylindrical compartment 76 within partition 51 constitutes the continuation of the reactor loop and enters the upper connecting channel 77 to the reaction volume 6. The circulation of reactor contents in the reactor loop thus descends into the reaction volume 6, through the channel 5, upwardly into the separation volume 7 and through the channel. 77. The connecting duct 77 preferably opens centrally in the top plate 72, and in the connecting duct 77, one or more places may be introduced for liquid and / or gaseous material supply means 30. The entrained material 20 50 may be reactor contents which, after being discharged through the tube 99, may have been reconditioned as described earlier in the text.

In Figure 2, 6 preferably represents a cylindrical shell-shaped reaction volume upwardly delimited by the top wall 88, downwardly delimited by the bottom wall 87, outwardly delimited by the vertical container wall 8, and inwardly delimited by its lower portion of the cylindrical wall 9 and in its upper portion of the cylindrical wall. 19. In the circulation of reactor contents in the reactor loop, the reactor contents move downwardly in the reaction volume 6, about the lower edge 57, which may be thickened, of the cylindrical wall 9 and upwards in the lower cylindrical shell 97 between the cylindrical wall 9 and the central, cylindrical tubes 22. The reactor contents then move through a garland of helical ducts 58 in the cylindrical shell-shaped volume 7, which ducts are delimited by the wall 9 and 30 the tube 22, and by baffles with lower leading edges 60 and upper trailing edges 62, and further upward the cylindrical shell-shaped separation volume 7 between the wall 9 and the pipe 22. The volume of separation 7 a is joined upwardly by the cylindrical partition 51, which, together with the wall 9, defines the outer cylindrical shell conduit 16. The manifold 17 and the tube 99 are as in FIG. 1. The cylinder shell-shaped passage 96 between the partition 51 and the pipe 22 leads to yet another garland of helical channels. 98, which increases the rotational speed of the reactor contents such that a G value higher than the G value in the separation volume 7 is obtained therein. 100 and 102 are respectively. lower leading edges and upper trailing edges for baffles between the screw ducts 98. The screw ducts 98 can be avoided if higher G value is not desired. From the channels 98, the reactor contents move upwardly in the cylinder shell-shaped separation volume 13, which includes both the passage 96, the channels 98 and the further volume between the tube 22 and the wall 19, which is a continuation of the partition 51, up to the next cylindrical partition 21. the inner fraction 40 of reactor contents is milled through the cylinder shell-shaped passage 3 between the tube 22 and the partition wall 21. The top piece 89 forces the undrained inner fraction downwards and out through the interior of the tube 22. The cylindrical shell 2 between the partition 21 and the wall 19 constitutes the continuation of the reactor loop and opens at the top of the upper edge of the wall 19 into the reaction volume 6. The separation process leading to the division of reactor contents into an outer fraction and an inner fraction into the separation volume 13 will be begun already in the separation volume 7, 45 why the two volumes can be perceived as one centrifugal separator with two separation steps, even though the two separation volumes are structurally constructed as two series-coupled centrifugal separators. In the passage 2 is placed a wreath of nozzle means 30 which receives liquid from a conduit 50 and gas, e.g. air, from conduits 29. The nozzle means 30

Claims (10)

25 The plate is twisted out of plan but is not curved. However, the plate may, if desired, be curved, e.g. as described in WO 91/09111. The screw threads 98 are designed in the same way as the screw threads 58, only with a much lower pitch of the screw guide plates that a higher G value is obtained. For further elucidation and explanation of the invention, the following should be noted: It is not essential for the function of the reactor that the reactor contents move downwardly in the reaction volume 6 and upwardly into the separation volumes 7 and 13. For both depicted embodiments, the reactor can, like all 35 embodiments in WO. 91/09111, is positioned with any axis direction, e.g. however, horizontally or with the reactor content moving upwardly in reaction volume 6 and downwardly in separation volumes 7 and 13. However, the downward movement of the reaction volume and upwardly in the separation volumes is advantageous in separating bubbles from liquid, with other axes requiring higher G value during separation. 40 PATENT REQUIREMENTS A method for carrying out a chemical, biochemical or biological reaction or production in a loop reactor in which immiscible phases are introduced or produced, characterized in that all or substantially all of the reactor contents for each circuit passage are passed through the reactor's reaction loop. into one end of a centrifugal separator integrated in the reaction loop and the reactor contents passing through the other end of the centrifugal separator into at least two fractions having different contents of at least two immiscible phases, separating two fractions at the other end of the centrifugal separator physically apart, so that the outer, heavier of the two fractions are directed from the reaction loop, while the inner, lighter of the two fractions is advanced further into the reaction loop. DK 168712 B1 8 Process according to claim 1, characterized in that the considered inner fraction during its passage through the reaction loop is still rotating, thereby separating into another outer and an inner fraction, the outer fraction being continued in the reaction loop while the inner of the these latter fractions are called the reaction loop. Loop reactor for performing the method of claim 1, comprising a reaction loop having a reaction volume (6) and drive means (30) for operating the circulation in the reaction loop and a centrifugal separator characterized in that the centrifugal separator in end has feed means (5,12,97,58) through which all or substantially all of the reactor contents are fed to the centrifugal separator for each circuit passage of the reactor contents through the reaction loop, whereby the reactor contents are divided into at least two fractions of different contents 10 and at least two different components and the centrifugal separator at its other end has means (51) for separating the two fractions into an inner fraction and an outer fraction, means (16) for separating the outer of these two fractions from the reaction loop and means (76.96) for furthering the interior of these two fractions in the reaction loop. Loop reactor according to claim 3, characterized in that the means (96) for carrying the inner fraction in the reaction loop leads to a further centrifugal separator (13) in the reaction loop, in which further centrifugal separator the internal fraction is divided into yet another outer and an inner fraction, of which two latter fractions the inner through a member (3) are led from the reaction loop, while the outer one through a member (2) is advanced into the reaction loop. Loop reactor according to claim 3 or 4, characterized in that a part or all of the separated, external fraction as considered in claim 3 is returned to the reaction loop. Loop reactor according to claim 5, characterized in that the return line takes place via a line (54), a pump (28) and a further line (50) for pressure drop nozzles mouthing into the reaction loop. 25 Loop reactor according to Claim 4, characterized in that part or all of the separated-lead internal fraction as recited in Claim 4 is returned to the reaction loop. Loop reactor according to claims 6 and 7, characterized in that the return of the considered part or whole 30 of the inner fraction takes place via a line (49), which optionally leads to a line (25) via a separator (23). leading to the pump (28). Loop reactor according to claims 5 and 7, characterized in that the return of the considered part or whole of the internal fraction takes place via a conduit (49), which optionally leads via a separator (23) to a conduit (25) which leads 35 to the reaction loop, preferably adjacent to the return site of the portion or whole of the outer fraction considered in claim 5. Loop reactor according to claims 6 and 7, characterized in that the return of the considered part or whole of the internal fraction takes place via a line (49), which optionally leads via a separator (23) to a line (25) which 40 leads to nozzle means (30) containing the pressure drop nozzles as claimed in claim 6, which nozzle means (30) act as ejectors, to which the conduit (50) from the pump (28) conducts propellant fluid while the contents of the conduit (25) guide the considered portion or whole of the internal fraction In the ejector is sucked and / or entrained by the driving fluid.