Reactor System and Method for Producing and/or Treating Particles

Abstract

A reactor system and a method for the production and/or treatment of particles in an oscillating process gas stream. The reactor system includes a reaction unit and a pulsation device. A pulsation that has a pulsation frequency and a pulsation pressure amplitude can be imposed on the process gas by means of the pulsation device. The pulsation device can adapt a pulation frequency and/or pulsation pressure amplitude of the pulsation to one of the inherent resonance frequencies of a resonator.

Claims

1. A reactor system for the production and/or treatment of particles in an oscillating process gas stream, the reactor system comprising: a reactor unit that has an upstream process gas feed unit and a downstream process gas discharge unit, which reactor unit has at least one reaction space for particle production and/or treatment and an application device for introducing a starting substance into the reactor that comprises the reaction spacer, wherein the process gas that flows through the reactor unit in the direction of the process gas discharge unit can be fed to the reactor unit by way of the process gas feed unit, wherein the reactor system further comprises a pulsation device that is suitable for the production of a pulsation of a process gas, wherein a pulsation that has a pulsation frequency and a pulsation pressure amplitude can be imposed on the process gas by means of the pulsation device, and wherein the reactor system, which has a static process gas pressure , is configured as an acoustic resonator that has inherent resonance frequencies that define a resonance state, in each instance, and the process gas can form a gas column capable of resonance in the reactor system, so that the resonator can be excited by means of the pulsation generated by the pulsation frequency and/or the pulsation pressure amplitude that is/are generated by the pulsation device, and in the resonance state, the pulsation can be amplified to produce a resonance oscillation of the process gas that has a resonance frequency and a resonance pressure amplitude, wherein the process gas feed unit and the process gas discharge unit each comprise a pressure loss production device that produces a pressure loss, wherein the pressure loss production devices are configured in such a manner that one of the resonance states can be optionally set, and wherein the pulsation device is configured for adapting the pulsation frequency and/or the pulsation pressure amplitude of the pulsation to one of the inherent resonance frequencies of the resonator, so that the selected resonance state can be achieved.

2. The reactor system according to claim 1, wherein the pulsation device is configured as a pulsation device that works without a flame.

3. The reactor system according to claim 1, wherein the reactor system has a heating device for heating the process gas.

4. (canceled)

5. The reactor system according to claim 1, wherein the pressure loss production devices are arranged in the process gas feed unit and the process gas discharge unit, in their corresponding position in the operating state, in an unchangeable manner.

6. The reactor system according to claim 1, wherein the pulsation device is configured as a pressure loss production device.

7. The reactor system according to claim 1, wherein a process gas volume stream regulation device is arranged upstream from the at least one reactor.

8. The reactor system according to claim 7, wherein the process gas volume stream regulation device is arranged downstream from the pulsation device.

9. The reactor system according to claim 7, wherein the process gas volume stream regulation device is configured as a sliding gate valve, regulating valve, regulating cock or an iris shutter that can be regulated.

10. The reactor system according to claim 7, wherein the process gas volume stream regulation device has a regulation precision of less than or equal to 3%.

11. The reactor system according to claim 1, wherein a process gas stream divider device is arranged upstream from the at least one reactor, so that at least one process gas feed line is assigned to each reactor of the reactor unit.

12-15. (canceled)

16. The reactor system according to claim 1, wherein the process gas feed unit and the process gas discharge unit have a process gas pressure regulation device, so that the static process gas pressure in the reactor system can be regulated.

17. The reactor system according to claim 1, wherein the process as discharge device has a plurality of process gas discharge lines, wherein each process gas discharge line has a pressure loss production device.

18. The reactor system according to claim 1, wherein the pulsation device is configured as a compression module or as a rotary vane or as a modified turnstile.

19. (canceled)

20. A method for the production and/or treatment of particles in an oscillating process gas stream using a reactor system having comprising a reactor unit that has an upstream process gas feed unit and a downstream process gas discharge unit, which reactor unit has at least one reaction space for particle production and/or treatment and an application device for introducing a starting substance into the reactor that comprises the reaction space, wherein the process gas that flows through the reactor unit in the direction of the process gas discharge unit is fed to the reactor unit by way of the process gas feed unit, and the reactor system comprises a pulsation device that is suitable for the production of a pulsation of a process gas, wherein a pulsation that has a pulsation frequency and a pulsation pressure amplitude is imposed on the process gas by means of the pulsation device, and wherein the reactor system, which has a static process gas pressure, is configured as an acoustic resonator that has inherent resonance frequencies that define a resonance state, in each instance, and the process gas forms a gas column capable of resonance in the reactor system, so that the resonator is excited by means of the pulsation generated by the pulsation frequency and/or the pulsation pressure amplitude that is/are generated by the pulsation device, and in the resonance state, the pulsation is amplified to produce a resonance oscillation of the process gas that has a resonance frequency and a resonance pressure amplitude, and wherein the process gas feed unit and the process gas discharge unit each comprise a pressure loss production device that produces a pressure loss, wherein the pressure loss production devices are configured in such a manner that one of the resonance states can be optionally set, wherein the pulsation frequency and/or the pulsation pressure amplitude of the pulsation is adapted to one of the inherent resonance frequencies of the resonator by means of the pulsation device, so as to achieve the selected resonance state.

21. The method according to claim 20, wherein a periodic pulsation is imposed on the process gas.

22. The method according to claim 20, wherein the pulsation frequency or a whole-number multiple of it is set close to the resonance frequency of the resonator.

23. (canceled)

24. (canceled)

25. The method according to claim 20, wherein a pulsation frequency from 1 Hz to 2000 Hz is imposed on the process gas by means of the pulsation device.

26. The method according to claim 20, wherein a pulsation pressure amplitude from 0.1 mbar to 350 mbar is imposed on the process gas by means of the pulsation device.

27. The method according to claim 20, wherein a pulsation frequency from 40 Hz to 160 Hz and a pulsation pressure amplitude from 10 mbar to 40 mbar is imposed on the process gas by means of the pulsation device.

28. The method according to claim 20, wherein the pressure loss production devices, in the operating state, are not changed in terms of their respective positions.

29-30. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In the following, the invention will be explained in greater detail using the attached drawing, which shows:

[0038] FIG. 1 a schematic representation of a first embodiment of a preferred reactor system,

[0039] FIG. 2 a schematic representation of a second embodiment of a preferred reactor system,

[0040] FIG. 3 a schematic representation a third embodiment of a preferred reactor system,

[0041] FIG. 4 a schematic representation a fourth embodiment of a preferred reactor system,

[0042] FIG. 5 a schematic representation of a fifth embodiment of a preferred reactor system, and

[0043] FIG. 6 a diagram of the resonance pressure amplitude plotted above the resonance frequency at three different positions in the reactor system.

DETAILED DESCRIPTION

[0044] If no information to the contrary is stated, the following description relates to all the embodiments of a reactor system 1 illustrated in the drawing, for the production and/or treatment of particles P in an oscillating process gas stream.

[0045] The reactor system 1 has a reactor unit 2, which is preceded by a process gas feed unit 3 and followed by a process gas discharge unit 4.

[0046] The reactor system 1 comprises a process gas conveying device 5 and a heating device 6. The process gas PG that flows through the reactor system 1 enters into the reactor system 1 by way of the process gas feed unit 3, and is conveyed through the reactor system 1 by means of the process gas conveying device 5.

[0047] The process gas conveying device 5 is configured, for example, in particular as a radial ventilator, blower or compressor. The process gas conveying device 5 can be arranged, in particular, in the process gas feed unit 3, the process gas discharge unit 4 or alternatively both in the process gas feed unit 3 and in the process gas discharge unit 4. In the embodiments of FIGS. 1, 2, and 4, placement of the process gas conveying device 5 in the process gas feed unit 3 is shown; in FIG. 5 the process gas discharge unit 4 has the process gas conveying device 5. FIG. 3 represents an embodiment having two process gas conveying devices 5, which are arranged both in the process gas feed unit 3 and also the process gas discharge unit 4. The placement of the process gas conveying device 5 is adapted to the conditions to be set in the reactor system 1, in particular with regard to shape, mass, and density of the starting substance.

[0048] The heating device 6 can be arranged upstream or downstream from a pulsation device 7. Placement upstream from the pulsation device 7 - for example as shown in the embodiments of FIGS. 1, 2, 3, and 5 - is preferred, since in the case of such an arrangement, the heating device 6 does not damp a resonance pressure amplitude in the reactor system 1. Placement downstream from the pulsation device 7 is disclosed in the embodiment shown in FIG. 2. The placement of the heating device 6 decides the assignment of the heating device 6 to the reactor unit 2 or to the process gas feed unit 3. A heating device 6 arranged upstream from the pulsation device 7 is assigned to the process gas feed unit 3, a heating device 6 arranged downstream from the pulsation device 7 is assigned to the reactor unit 2.

[0049] Preferably the heating device 6 is configured as a convective gas heater, an electric gas heater, a plasma heater, a microwave heater, an induction heater or a radiation heater. It is less preferred for the heating device 6 to be configured as a burner that has a flame.

[0050] The process gas PG that flows through the reactor system 1 is warmed or heated to a production and/or treatment temperature by means of the heating device 6. The temperature for the production or thermal treatment of the at least one starting substance preferably lies between 100° C. and 3000° C., preferably at 240° C. to 2200° C., particularly preferably at 240° C. to 1800° C., very particularly preferably at 650° C. to 1800° C., most preferably at 700° C. to 1500° C.

[0051] A pulsation having a pulsation frequency and a pulsation pressure amplitude is imposed on the process gas PG that flows through the reactor system 1 by means of the pulsation device 7. The pulsation preferably has a pulsation pressure amplitude of 0.1 mbar to 350 mbar, particularly preferably of 1 mbar to 200 mbar, very particularly preferably of 3 mbar to 50 mbar, most preferably of 10 mbar to 40 mbar.

[0052] The pulsation frequency of the process gas PG can be set independently of the pulsation pressure amplitude. The pulsation frequency of the process gas PG that flows through the reactor system 1, pulsating due to the pulsation device 7, can also be adjusted, preferably in the frequency range of 1 Hz to 2000 Hz, preferably between 1 Hz to 500 Hz, particularly preferably between 40 Hz and 160 Hz.

[0053] The pulsation device 7 is configured as a pulsation device 7 that works without a flame. It is practical if the pulsation device 7 is configured as a compression module, in particular as a piston, or as a rotary vane or as a modified turnstile.

[0054] The reactor 9, which has a reaction space 8 and is assigned to the reactor unit 2, is formed downstream from the process gas feed unit 3. In the reaction space 8 of the reactor 9, a pulsating process gas PG that flows through the reactor system 1 and the reactor 9 is introduced into the starting substance by means of an application device 10.

[0055] The application device 10 is preferably configured for introduction of liquids or solids into the reaction space 8 of the reactor 9.

[0056] Liquids or liquid raw materials (precursors) can be introduced into the reaction space 8 preferably as a solution, suspension, melt, emulsion or as a pure liquid. The introduction of the liquid raw materials or liquids preferably takes place continuously. For the introduction of liquids into the reaction space 8 of the reactor 9 of the reaction unit 2, an application device 10 is preferably used, such as, for example, spray nozzles, feed pipes or droplet dispensers, which are configured, for example, as single-substance or multi-substance nozzles, pressure nozzles, nebulizers (aerosol) or ultrasound nozzles.

[0057] In contrast to this, for the introduction of solids, for example powders, granulates or the like, into the reactor 9, preferably into the reaction space 8 of the reactor 9, an application device 10 is preferably used, such as, for example, a double flap, a rotary feeder, a batching valve or an injector.

[0058] The introduction of the starting substance in the form of a liquid or of a solid can take place in or counter to the flow direction of the process gas PG that flows through the reactor system 1. In the embodiments of FIGS. 1 and 3 to 5, application of the starting substance takes place in the flow direction of the process gas; in the embodiment shown in FIG. 2, application of the starting substance takes place counter to the flow direction of the process gas.

[0059] Preferably the starting substance is introduced into the reactor system 1, preferably into the reaction space 8 of the reactor 9, using a carrier gas. The decision as to whether the starting substance is introduced into the reactor system 1 in or counter to the flow direction of the process gas depends decisively on the shape, mass, and density of the starting substance at a set average flow speed of the process gas PG. As a result, the possibility exists of also thermally treating starting substances that cannot be transported in the reactor system 1 by means of the process gas PG.

[0060] The starting substance is treated thermally in the treatment zone of the reactor 9, preferably in the reaction space 8, so that the particles P to be produced, preferably the inorganic or organic nano-particles, particularly preferably the nano-crystalline metal oxide particles, are formed. The region in which the starting substances are treated thermally is defined as the treatment zone.

[0061] The process gas discharge unit 4 that follows the reaction unit 2 comprises a separation device 11. The separation device 11, in particular a filter, preferably a hot gas filter, very particularly preferably a tubular, metal or fiberglass filter, a cyclone or a washer, separates the thermally treated particles P from the pulsating, hot process gas stream that flows through the reactor system 1. The particles P that are removed from the process gas stream are drawn off from the separation device 11 and processed further. If necessary, the particles P that have been thermally treated in the reactor system 1 are subjected to further subsequent treatment steps, such as, for example, suspension, grinding or calcination. The non-charged process gas PG is conducted away into the environment.

[0062] The dwell time of the one starting substance introduced into the reactor system 1, in particular into the reaction space 8 of the reactor 9, lies between 0.1 s and 25 s. Closed-cycle operation of the process gas PG is possible. If applicable, partial removal of the process gas PG from the circuit is also possible.

[0063] Furthermore, the reactor system 1, which has a static process gas pressure, is configured as an acoustic resonator 12, which has inherent resonance frequencies that each define a resonance state. The process gas PG can form a gas column that is capable of resonance in the reactor system 1, so that the resonator 12 can be excited by means of the pulsation frequency and/or the pulsation pressure amplitude of the pulsation that is generated by means of the pulsation device 7, and in the resonance state, the pulsation can be amplified to produce a resonance oscillation of the process gas PG that has a resonance frequency and a resonance pressure amplitude.

[0064] The process gas feed unit 3 and the process gas discharge unit 4 each comprise a pressure loss production device 13 that produces a pressure loss, wherein the pressure loss production devices 13 are configured in such a manner that optionally one of the resonance states of the resonator 12 can be set. The pressure loss production devices 13 limit a system 14 of the reactor system 1 that is capable of oscillation and oscillates in the operating state, geometrically and with regard to the process gas volume of the gas column that is formed and is capable of resonance. The pressure loss production devices 13 thereby prevent propagation of the resonance oscillation beyond the pressure loss production devices 13. The more limited the system 14 is, which is capable of oscillation or oscillates in the operating state, the more effective production and propagation of the resonance oscillation in the system 14 will be.

[0065] The pulsation device 7 is preferably configured as a pressure loss production device 13. Such a preferred embodiment of the pulsation device 7 is shown in the embodiments of FIGS. 1, 3, and 5.

[0066] The pressure loss production devices 13 are arranged in the reactor system 1, in particular in the process gas feed unit 3 and the process gas discharge unit 4, so that their respective positions can be changed, wherein in the operating state, the pressure loss production devices 13 cannot be changed in terms of the position that has previously been set. In this way, it is ensured that the system 14, which oscillates in the operating state, does not change.

[0067] The pulsation device 7 of the reactor system 1 is configured for adapting the pulsation frequency and/or the pulsation pressure amplitude of the pulsation to one of the inherent resonance frequencies of the resonator 12, in such a manner that the selected resonance state can be achieved. Particularly preferably, the pulsation frequency or a whole-number multiple of it is set close to the resonance frequency of the resonator 12, so that the resonator 12 is excited and a resonance oscillation occurs in the system 14, which is capable of oscillation. By means of imposing a periodic pulsation onto the process gas, wherein in particular the pulsation frequency or a whole-number multiple of it is set close to the resonance frequency of the resonator 12, in a targeted manner, amplification of the resonance oscillation of the process gas, which has a resonance frequency and a resonance pressure amplitude, is achieved. In this way, the heat transfer and material transfer properties of the preferably hot process gas in the reactor system 1 are improved.

[0068] In the case of certain processes, it is advantageous to be able to set or regulate the static pressure in the reactor system 1. For this purpose, the reactor system 1, in particular the process gas feed unit 3 and the process gas discharge unit 4, has/have a process gas regulation device 15. The embodiment of FIG. 3 discloses such an arrangement.

[0069] The pressure loss production devices 13 that limit the system 14, which is capable of oscillation or oscillates in the operating state, are arranged within the process gas regulation device 15. Upstream from the reactor unit 2, the process gas regulation device 15 is therefore arranged upstream from the pressure loss production devices 13, and downstream from the reactor unit 2, it is arranged downstream from the pressure loss production devices 13. Without such a process gas regulation device 10, the static process gas pressure in the reactor system 1 corresponds to atmospheric pressure.

[0070] By means of adapting the static process gas pressure in the reactor system 1, an influence can be exerted on the properties of the acoustic resonator 12. Flow resistances, acoustic phenomena, and changes in the material properties of the process gas as well as of the starting substance applied to it can damp the resonance oscillation. The energy expenditure for resonance oscillation production is accordingly increased and/or the ability to regulate the resonance oscillation is influenced. In particular, the reactor system 1 can be adapted, in this way, to the factors that damp the resonance pressure amplitude of the resonance oscillation.

[0071] A higher static process gas pressure changes the acoustic properties of the resonator 12, for example to the effect that its inherent resonance frequencies shift. For this reason, excitation of the reactor system 1 is possible only by means of the imposition of other pulsation frequencies onto the process gas.

[0072] In addition, the pulsation pressure amplitude imposed on the process gas by means of the pulsation device 7, and thereby also the resonance pressure amplitude in the resonance state is amplified.

[0073] In addition, the reactor system 1 can also comprise a process gas cooling segment 16, shown in FIG. 5, for example, in particular a quenching apparatus, which is used to stop the reaction taking place in the reactor system 1 at a certain point in time and/or to adapt the process gas stream to a maximally permissible temperature of a subsequent separation device 11, in particular a filter. The process gas cooling segment 16, preferably the quenching apparatus, is arranged, here, in the process gas discharge unit 4, upstream from the separation device 11 that is configured as a filter.

[0074] To stop the reaction and/or to limit the temperature of the process gas stream to a maximally permissible temperature of a subsequent separation device 11, a cooling gas is mixed into the pulsating, hot process gas stream that flows through the reactor system 1, by way of the process gas cooling segment 16, preferably air, particularly preferably cold air or compressed air. The air mixed in by way of the process gas cooling segment 16 can be filtered or conditioned beforehand, if necessary, depending on the requirements. Furthermore, it is possible, alternatively to mixing in air or gas, to undertake injection of an evaporating liquid, for example of solvents or liquefied gases, but preferably of water.

[0075] The quenching apparatus 16 arranged in the reactor system 1 can have fittings or is built into the reactor system 1 without fittings. Other gases, such as, for example, nitrogen (N.sub.2), argon (Ar), other inert gases or noble gases or the like can also be used as a cooling gas.

[0076] Furthermore, it can be practical if a process gas volume stream regulation device 17 is arranged upstream from the at least one reactor 9. The embodiments of FIGS. 3, 4, and 5 show process gas volume stream regulation devices 17. Preferably the process gas volume stream regulation device 17 is arranged downstream from the pulsation device. The process gas volume stream regulation device 17 is configured, in particular, as a sliding gate valve, regulating valve, regulating cock or an iris shutter that can be regulated. The process gas volume stream regulation device 17 has a regulation accuracy of less than or equal to 3 %, preferably of less than or equal to 2 %, particularly preferably of less than or equal to 1 %, and most preferably of less than or equal to 0.5 %. The process gas volume stream regulation 17, which demonstrates great regulation accuracy, is necessary so as to minimize or prevent feedback to the process gas volume stream caused by the resonance oscillation. In particular, great regulation precision of the process gas volume stream is necessary when using a process gas stream divider device 18, so that the system 14, which is capable of oscillation or oscillates in the operating state can be operated in a sufficiently stable manner.

[0077] If the reactor unit 2, as shown in the embodiment of FIG. 4, has a plurality of reactors 9, a process gas stream divider device 18 is arranged upstream from the reactors 9, so that at least one process gas feed line 19 is assigned to each reactor 9 of the reactor unit 2.

[0078] Preferably the process gas stream divider device 18 is arranged downstream from the pulsation device 7, and each process gas feed line 19 has a process gas volume stream regulation device 17. Each process gas feed line 19 is configured in such a manner that each process gas feed line 19 has a pressure loss between the process gas stream divider device 18 and a reactor inlet 20, wherein the pressure loss in each process gas feed line 19 is essentially the same. This result is achieved in that in particular the process gas feed lines 19 have the same process gas feed line length and/or the same process gas feed line inside diameter and/or other fittings that are the same.

[0079] Furthermore, the process gas discharge device 4 has a plurality of process gas discharge lines 21 that at least corresponds to the plurality of reactors 9, wherein each process gas discharge line 21 has a pressure loss production device 13.

[0080] The process gas discharge lines 21 are brought together, and the particles P are separated from the process gas stream, preferably from the hot process gas stream by way of the separation device 11.

[0081] FIG. 6 shows a diagram of the resonance pressure amplitude plotted above the resonance frequency at three different positions in the reactor system 1 at a process gas temperature of 300° C.

[0082] The curves x.sub.1 to x.sub.3 show the progression of the resonance pressure amplitude in the unit mbar at three different positions in the reactor system 1, namely directly after the pulsation device 7 (x.sub.1) , at the reactor inlet 20 (x.sub.2), and at the reactor outlet 22 (x.sub.3) .

[0083] The resonance oscillation corresponds to an amplified pulsation, so that the pulsation frequency and the resonance frequency agree.

[0084] The pulsation pressure amplitude was set at approximately 15 mbar, as can be read from the average pulsation pressure amplitude directly after the pulsation device 7, wherein this amplitude varies minimally with a different pulsation frequency in the system 14.

[0085] From the diagram, it is possible to read 60 Hz as the inherent resonance frequency of the resonator 12, since here the greatest resonance pressure amplitude of about 70 mbar occurs at the reactor inlet 20.

[0086] At the reactor outlet 22, a resonance pressure amplitude of about 35 mbar can be read at the inherent resonance frequency of 60 Hz. The reduction in the resonance pressure amplitude between reactor inlet 20 and reactor outlet 22 can be explained by the damping of the system 14, because the application of the application substance, for example, as well as flow resistances damp the resonance pressure amplitude of the system 14.