METHOD FOR SELF-REGULATION OF A SYSTEM

Abstract

The invention relates to a method for self-regulation of a system comprising the steps of: (I) utilizing a magnetic field to transport magnetizable and/or magnetic particles out of a control volume or to localize said particles in the control volume, (II) changing magnetic properties of the magnetizable and/or magnetic particles, which are ferromagnetic or paramagnetic, in the control volume by changing a temperature Tp of the magnetizable and/or magnetic particles or by changing the composition of the magnetizable and/or magnetic particles.

Claims

1-18. (canceled)

19. A method for self-regulation of a system, the method comprising: (I) utilizing a magnetic field to transport magnetizable and/or magnetic particles out of a control volume or to localize said particles in the control volume, wherein the magnetizable and/or magnetic particles: a. are localized in the control volume by the magnetic field, when said particles have ferromagnetic properties, and transported out of the control volume by a flowing fluid or gravity, when said particles have paramagnetic properties, or b. are transported out of the control volume by the magnetic field, when said particles have ferromagnetic properties, and are localized in the control volume, when said particles have paramagnetic properties, and (II) changing magnetic properties of the magnetizable and/or magnetic particles, which are ferromagnetic or paramagnetic, in the control volume by changing a temperature Tp of the magnetizable and/or magnetic particles or by changing the composition of the magnetizable and/or magnetic particles, wherein at least one chemical reaction is carried out in the control volume.

20. The method according to claim 19, wherein the magnetic field is a moving magnetic field.

21. The method according to claim 19, wherein the temperature Tp increases and the magnetizable and/or magnetic particles are transported out of the control volume when their temperature Tp is higher than their Curie temperature Tc.

22. The method according to claim 19, wherein the at least one chemical reaction is an exothermic reaction.

23. The method according to claim 22, wherein the temperature Tp increases and at least part of the energy for elevating the temperature Tp is liberated by the exothermic reaction.

24. The method according to claim 19, wherein the temperature Tp decreases and the magnetizable and/or magnetic particles are transported out of the control volume when their temperature Tp is lower than their Curie temperature Tc.

25. The method according to claim 19, wherein the at least one chemical reaction is an endothermic reaction.

26. The method according to claim 25, wherein the temperature Tp decreases and at least part of the energy emitted by the magnetizable and/or magnetic particles is utilized for carrying out the endothermic reaction.

27. The method according to claim 19, wherein the magnetizable and/or magnetic particles catalyze the at least one chemical reaction or comprise a catalytically active material.

28. The method according to claim 19, wherein the magnetizable and/or magnetic particles are a reactant or a product of the at least one chemical reaction or comprise a reactant or a product of the at least one chemical reaction.

29. The method according to claim 19, wherein once transported out of the control volume the magnetizable and/or magnetic particles are cooled or heated and/or regenerated and recycled into the control volume.

30. The method according to claim 19, wherein the composition of the magnetizable and/or magnetic particles changes by the at least one chemical reaction changing an oxidation state of at least one component of the magnetizable and/or magnetic particles.

31. The method according to claim 19, wherein the control volume is part of a fixed bed reactor, an expanded bed reactor, a fluidized bed reactor or a suspension reactor.

32. The method according to claim 19, wherein the at least one chemical reaction is a hydrogenation.

33. The method according to claim 19, wherein a difference between the Curie temperature Tc of the magnetizable and/or magnetic particles and a reaction temperature Tr of the at least one chemical reaction is not more than 150 K.

34. The method according to claim 22, wherein the exothermic reaction is carried out at a control reaction temperature Tcr which is lower than a threshold temperature Tt, the Curie temperature Tc of the magnetizable and/or magnetic particles has been adjusted such that the Curie temperature Tc of the magnetizable and/or magnetic particles is higher than the reaction temperature Tr and lower than the threshold temperature Tt and a difference between the Curie temperature Tc of the magnetizable and/or magnetic particles and the threshold temperature Tt is not more than 20 C. and the magnetic properties of the magnetizable and/or magnetic particles only change when the reaction temperature Tr, which is initially equal to the control reaction temperature Tcr, increases causing the temperature Tp of the magnetizble and/or magnetic particles to increase and the temperature Tp of the magnetizable and/or magnetic particles to exceed the Curie temperature Tc.

35. The method according to claim 23, wherein the exothermic reaction is carried out at a control reaction temperature Tcr which is lower than a threshold temperature Tt, the Curie temperature Tc of the magnetizable and/or magnetic particles has been adjusted such that the Curie temperature Tc of the magnetizable and/or magnetic particles is higher than the reaction temperature Tr and lower than the threshold temperature Tt and a difference between the Curie temperature Tc of the magnetizable and/or magnetic particles and the threshold temperature Tt is not more than 20 C. and the magnetic properties of the magnetizable and/or magnetic particles only change when the reaction temperature Tr, which is initially equal to the control reaction temperature Tcr, increases causing the temperature Tp of the magnetizble and/or magnetic particles to increase and the temperature Tp of the magnetizable and/or magnetic particles to exceed the Curie temperature Tc.

36. The method according to claim 30, wherein the exothermic reaction is carried out at a control reaction temperature Tcr which is lower than a threshold temperature Tt, the Curie temperature Tc of the magnetizable and/or magnetic particles has been adjusted such that the Curie temperature Tc of the magnetizable and/or magnetic particles is higher than the reaction temperature Tr and lower than the threshold temperature Tt and a difference between the Curie temperature Te of the magnetizable and/or magnetic particles and the threshold temperature Tt is not more than 20 C. and the magnetic properties of the magnetizable and/or magnetic particles only change when the reaction temperature Tr, which is initially equal to the control reaction temperature Tcr, increases causing the temperature Tp of the magnetizble and/or magnetic particles to increase and the temperature Tp of the magnetizable and/or magnetic particles to exceed the Curie temperature Tc.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0066] Operative examples of the invention are shown in the figures and will be more particularly described in the description which follows.

[0067] FIG. 1 is a schematic diagram of an exothermic reaction in a magnetically enhanced fluidized bed with self-regulating temperature management.

[0068] FIG. 2 is a schematic diagram of an exothermic reaction in a magnetically enhanced fluidized bed with self-regulating temperature management and recycling of magnetizable and/or magnetic particles.

[0069] FIG. 3 is a schematic diagram of an exothermic reaction in a batch reactor with alternating magnetic field and self-regulating temperature management.

[0070] FIG. 4 is a schematic diagram of an endothermic reaction in a fluidized bed with self-regulating temperature management.

[0071] FIG. 5 is a schematic diagram of an endothermic reaction in a fluidized bed with self-regulating temperature management and lateral heating element.

[0072] FIG. 6 is a schematic diagram of an endothermic reaction in a batch reactor with self-regulating temperature management.

[0073] FIG. 7 is a schematic diagram of an endothermic reaction in a batch reactor with self-regulating temperature management and magnetic conveying.

[0074] FIG. 8 shows conversions of nitrobenzene in the presence of magnetizable and/or magnetic particles.

[0075] FIG. 9 shows temperature profiles for heating of magnetizable and/or magnetic particles.

[0076] FIG. 1 is a schematic diagram of an exothermic reaction in a magnetically enhanced fluidized bed with self-regulating temperature management.

[0077] FIG. 1 shows a first fluidized bed 1 in which an exothermic reaction is carried out. To this end, a fluid phase 4 comprising at least one reactant flows through the first fluidized bed 1 which is bounded by a reactor wall 6. The first fluidized bed 1 comprises fluidized magnetizable and/or magnetic particles. The magnetizable and/or magnetic particles are catalytically active with respect to the exothermic reaction carried out in the first fluidized bed 1. At least one magnet coil 5 is used to generate a static magnetic field in the region of the first fluidized bed 1 and said field stabilizes the fluidized bed and exerts on magnetic particles a force acting in a direction opposite to the flow direction 7 of the fluid phase 4. A first portion 2 of the magnetizable and/or magnetic particles has a temperature Tp2 lower than the Curie temperature Tc of the particles. Thus, the first portion 2 of the magnetizable and/or magnetic particles is under the influence of the applied magnetic field. The movement of the first portion 2 of the magnetizable and/or magnetic particles in the first fluidized bed 1 is directionless and the first portion 2 of the magnetizable and/or magnetic particles remains in the first fluidized bed 1, has been localized in the first fluidized bed 1. A second portion 3 of the magnetizable and/or magnetic particles has a temperature Tp3 higher than the Curie temperature Tc of the particles. Thus, the second portion 3 of the magnetizable and/or magnetic particles is not influenced by the magnetic field. The force which is generated by the magnetic field and which acts in a direction opposite to the flow direction 7 is not applicable to the second portion 3 of the magnetizable and/or magnetic particles which is therefore discharged from the first fluidized bed 1 in flow direction 8. The temperature management in the first fluidized bed 1 is self-regulating. The progress of the heterogeneously catalyzed exothermic reaction raises the temperature in the fluidized bed and consequently also the temperature Tp of the magnetizable and/or magnetic particles and individual particles from the first portion 2 of the magnetizable and/or magnetic particles therefore pass into the second portion 3 of the magnetizable and/or magnetic particles, lose the influence of the magnetic field, are carried off by the fluid phase 4 and discharged from the first fluidized bed 1. This reduces the amount of catalyst in the first fluidized bed 1 and thus also reduces the reaction rate and the rate of temperature increase which, moreover, can also be influenced and controlled externally via the inflow of the fluid phase 4. Particles of the second portion 3 of the magnetizable and/or magnetic particles, which have been discharged from the first fluidized bed 1, may be cooled down and recycled into the fluidized bed.

[0078] FIG. 2 is a schematic diagram of an exothermic reaction in a magnetically enhanced fluidized bed with self-regulating temperature management and recycling of magnetizable and/or magnetic particles.

[0079] A second fluidized bed la shown in FIG. 2 differs from the first fluidized bed 1 shown in FIG. 1 in terms of the flow rate of the fluid phase 4 through the fluidized bed. The flow rate of the fluid phase 4 in FIG. 2 is lower and the second portion 3 of the magnetizable and/or magnetic particles, which is not under the influence of the magnetic field, therefore follows the gravitational force and sinks. In addition, the at least one magnet coil 5 is used to generate a magnetic field which exerts on magnetic particles a force acting in the flow direction 7 of the fluid phase 4. When the Curie temperature Tc of individual magnetizable and/or magnetic particles is exceeded, these exit the second fluidized bed la via a downpipe 24. The occasional magnetizable and/or magnetic particle of the first portion 2 could also enter the downpipe. However, the proportion of particles of the second portion 3 in the downpipe is generally greater than the proportion of particles of the first portion 2. A grid 23 surrounds the circumference of the downpipe 24 at the point of entry of the downpipe 24 into the second fluidized bed la and said grid connects the circumference of the downpipe 24 with the reactor wall 6. The fluid phase 4 can flow through the grid 23, while the magnetizable and/or magnetic particles cannot pass through the grid and the magnetizable and/or magnetic particles moving downward in their flow direction 8 are directed toward the downpipe 24. In the downpipe 24, the magnetizable and/or magnetic particles of the second portion 3 of the magnetizable and/or magnetic particles are directed past at least one cooling jacket 13 and, as a result, said particles cool down, their temperature falls below their Curie temperature Tc and they pass into the first portion 2 of the magnetizable and/or magnetic particles. The cooled-down magnetizable and/or magnetic particles are returned via a riser pipe 25 to the second fluidized bed la where they are again under the influence of the magnetic field until they are reheated as described in connection with FIG. 1 to a temperature above their Curie temperature Tc by the heterogenerously catalyzed exothermic reaction carried out in the second fluidized bed 1a.

[0080] FIG. 3 is a schematic diagram of an exothermic reaction in a batch reactor with alternating magnetic field and self-regulating temperature management.

[0081] In accordance with FIG. 3, in a first batch reactor 27 an exothermic reaction is carried out in a fluid phase 4 which comprises dispersed magnetizable and/or magnetic particles. At least one magnet coil 9 generates an alternating magnetic field which moves magnetic particles and ensures commixing in the first batch reactor 27. A first portion 2 of the magnetizable and/or magnetic particles, which has a temperature Tp2 lower than the Curie temperature Tc, is under the influence of the alternating magnetic field and is fluidized in the fluid phase. The progress of the exothermic reaction causes the temperature in the first batch reactor 27 and the temperature of the magnetizable and/or magnetic particles to increase and, as a result, individual magnetizable and/or magnetic particles of the first portion 2 are heated to a temperature Tp3 higher than their Curie temperature Tc and consequently pass into the second portion 3 of the magnetizable and/or magnetic particles. The second portion 3 of the magnetizable and/or magnetic particles is not under the influence of the alternating magnetic field and sinks downward. At the bottom of the first batch reactor 27 there is a cooling jacket 13 and sedimented particles of the second portion 3 of the magnetizable and/or magnetic particles come into contact with said cooling jacket and are cooled to a temperature Tp2 lower than their Curie temperature Tc. Now, these cooled-down particles are again under the influence of the alternating magnetic field and are again fluidized in the fluid phase 4. Magnetizable and/or magnetic particles of the second portion 3 are thus supplied to the cooling jacket 13 and cooled down in a self-regulating fashion. Magnetizable and/or magnetic particles of the first portion 2 are removed from the cooling jacket 13 in a self-regulating fashion as soon as their temperature falls below the Curie temperature Tc.

[0082] FIG. 4 is a schematic diagram of an endothermic reaction in a fluidized bed with self-regulating temperature management.

[0083] In FIG. 4, an endothermic reaction is carried out in a third fluidized bed 1b. A heating element 12 and at least one magnet coil 5 are disposed at the feed point of the fluid phase 4 below the third fluidized bed 1b. The third fluidized bed 1b initially comprises a second portion 3 of magnetizable and/or magnetic particles at a temperature Tp3 higher than the Curie temperature Tc of the particles. A feed point of the fluid phase 4 into the third fluidized bed lb is preferably chosen such that the second portion 3 of the magnetizable and/or magnetic particles does not reach the heating element 12 and the at least one magnet coil 5 due to a fluid velocity in flow direction 7 in a cross section at the height of heating element 12 and the at least one magnet coil 5 exceeding the discharge velocity of the second portion 3 of the magnetizable and/or magnetic particles at a point of entry into the third fluidized bed 1b. The progress of the endothermic reaction reduces the temperature of the magnetizable and/or magnetic particles and the temperature of individual magnetizable and/or magnetic particles falls below the Curie temperature Tc of said particles and they therefore pass into the first portion 2 of the magnetizable and/or magnetic particles and are under the influence of the magnetic field generated by the at least one magnet coil 5. The first portion 2 of the magnetizable and/or magnetic particles is attracted by the at least one magnet coil 5 and, on account of the now operative force additionally exerted by the magnetic field on the first portion 2 of the magnetizable and/or magnetic particles, moves in the direction of the at least one magnet coil 5 and the heating element 12 which are arranged such that the magnetic field of the at least one magnet coil 5 positions the magnetizable and/or magnetic particles of the first portion 2 in contact with or in proximity to the heating element 12. The magnetizable and/or magnetic particles positioned there are heated to a temperature Tp3 above their Curie temperature Tc by the heating element 12, thus pass into the second portion 3 of the magnetizable and/or magnetic particles, are no longer under the influence of the magnetic field and are transported in flow direction 7 back into the third fluidized bed 1b by the flowing fluid phase 4. When there is a secondary feed point of the fluid phase 4, at half of the height of the third fluidized bed 1b for example, a plurality of zones can be formed in the fluidized bed. Here, the method according to the invention can be employed to achieve a desired particle circulation in the different zones.

[0084] FIG. 5 is a schematic diagram of an endothermic reaction in a fluidized bed with self-regulating temperature management and lateral heating element.

[0085] A fourth fluidized bed 1c shown in FIG. 5 differs from the third fluidized bed 1b in that the heating element 12 and the at least one magnet coil 5 are disposed to the side of the fourth fluidized bed 1c. The directions of movement 8 and 11 of the magnetizable and/or magnetic particles 3 and of the magnetizable and/or magnetic particles 2 are thus not parallel to the flow direction 7 of the fluid phase 4. Moreover, in one embodiment of the fourth fluidized bed 1c the magnetizable and/or magnetic particles 3 can also coincidentally move in the direction of the at least one magnet coil 5 which is preferably prevented in the fluidized bed 1b described hereinabove due to the fluid velocity in the region of the at least one magnet coil 5 being high enough that particles can only arrive at the at least one magnet coil 5 and at the heating element 12 under the influence of the magnetic field.

[0086] FIG. 6 is a schematic diagram of an endothermic reaction in a batch reactor with self-regulating temperature management.

[0087] In accordance with FIG. 6, in a second batch reactor 27a an endothermic reaction is carried out in a fluid phase 4 comprising dispersed magnetizable and/or magnetic particles. Commixing is achieved via stirrer 10. At least one magnet coil 5 and a heating jacket 14 are together disposed on the reactor wall 6 such that a first portion 2 of the magnetizable and/or magnetic particles, which particles have a temperature Tp2 lower than their Curie temperature Tc, is under the influence of the magnetic field generated by the at least one magnet coil 5 and is drawn to the heating jacket 14. The progress of the endothermic reaction reduces the temperature Tp3 of the magnetizable and/or magnetic particles and the temperature of individual magnetizable and/or magnetic particles of the second portion 3 falls below the Curie temperature Tc of said individual particles and, as a result, they pass into the first portion 2 of the magnetizable and/or magnetic particles and are under the influence of the magnetic field generated by the at least one magnet coil 5. The first portion 2 of the magnetizable and/or magnetic particles is attracted by the at least one magnet coil 5 and moves in the direction of the at least one magnet coil 5 and the heating jacket 14 which are arranged such that the magnetic field of the at least one magnet coil 5 positions the magnetizable and/or magnetic particles of the first portion 2 in contact with or in proximity to the heating jacket 14. The magnetizable and/or magnetic particles positioned there are heated to a temperature Tp3 above their Curie temperature Tc by the heating jacket 14, thus pass into the second portion 3 of the magnetizable and/or magnetic particles, are no longer under the influence of the magnetic field and are carried off again by the stirred fluid phase 4 and removed from the heating jacket 14 and dispersed in a self-regulating fashion according to their temperature.

[0088] FIG. 7 is a schematic diagram of an endothermic reaction in a batch reactor with self-regulating temperature management and magnetic conveying.

[0089] An endothermic reaction is carried out in a third batch reactor 27b, shown in FIG. 7, in the manner of FIG. 6. However, magnet coils 26 for generating magnetic fields of a magnetic conveying system are disposed on the reactor wall 6 in place of the at least one magnet coil 5 and the heating jacket 14. A first portion 2 of the magnetizable and/or magnetic particles is under the influence of the magnetic fields of the magnet coils 26 and is removed from a reaction mixture consisting at least of the fluid phase 4 and the magnetizable and/or magnetic particles by means of the magnetic conveying system. Outside the third batch reactor 27b, the magnetizable and/or magnetic particles of the first portion 2 can be reheated to a temperature Tp3 above their Curie temperature Tc and recycled into the third batch reactor 27b via a feed line 21 for example. Alternatively or in addition, fresh magnetizable and/or magnetic particles at a temperature Tp3 above their Curie temperature Tc can be supplied to the third batch reactor 27b via the feed line 12.

[0090] In addition to the embodiments of FIGS. 1 to 7, further embodiments arise due to the magnetizable and/or magnetic particles, i.e., both the first portion 2 and the second portion 3, exhibiting no catalytic activity but rather being employed merely for heat transfer or due to the magnetic properties of the magnetizable and/or magnetic particles being brought about via a change in their composition such as change in the oxidation state in place of a temperature change.

Example 1 Production of a Solid for Use in Magnetic Particles

[0091] Three samples, M1, M2 and M3, were produced in different ways. All samples comprised iron oxide, copper oxide and nickel oxide. All samples consisted of 67.3% by weight of Fe.sub.2O.sub.3, 20.11% by weight of CuO and 12.59% by weight of NiO. To produce M1, the components Fe.sub.2O.sub.3, CuO and NiO were mixed in the stated ratio, milled in a mortar and calcined at 900 C. for 9 hours. To produce M2, NiCO.sub.3.2Ni(OH).sub.2, CuCO.sub.3.Cu(OH).sub.2 and Fe(NO.sub.3).sub.3.9H.sub.2O were milled, dried, initially at 120 C. for 16 hours then at 150 C. for 16 hours, and subsequently thermally decomposed, at 250 C. for 2 hours, then at 400 C. for 2 hours and then at 550 C. for 2 hours, to retain the corresponding oxides. The sample was then calcined at 900 C. for 9 hours. To produce M3, the corresponding metal hydroxides were co-precipitated with KOH at a pH of 10 and a temperature of 80 C. The sample was then dried at 100 C. for 16 hours and calcined at 350 C. for 4 hours. In order to enhance the hardness of the samples, all materials were tabletted and subsequently milled to a particle size of between 100 m and 300 m.

Example 2 Catalytic Activity of the Magnetic Particles

[0092] The catalytic activity of samples M2 and M3 was analyzed. To this end, in each case 2.5 g of a sample were charged to a glass bottle and 90 g of nitrobenzene and 90 g of aniline were added thereto. The mixture was purged with nitrogen in an autoclave and subsequently heated to 130 C. under 35 bar of hydrogen pressure and with stirring at 200 rpm. As soon as the temperature of 130 C. was reached, the stirring speed was increased to 1300 rpm in order to start the reaction.

[0093] The results are shown in FIG. 8. To this end, the conversion 17 of nitrobenzene in percent was plotted as a function of time t in hours. Both the conversion shown in graph 19 for sample M3, and the conversion shown in graph 20 for sample M2 increased over time, a higher conversion being achieved in the same time for sample M3. The NiCu ferrites analyzed consequently showed activity with respect to the hydrogenation of nitrobenzene.

Example 3 Changing the Magnetic Properties of Magnetic Particles

[0094] In order to observe the magnetic properties of the samples qualitatively, a pendulum experiment was carried out. A pendulum of non-magnetic material was filled with magnetic sample material. The pendulum was displaced from its rest position using a magnetic field generated by a permanent magnet. The pendulum displaced from its rest position was heated with hot air at a temperature of 600 C. generated by a gas burner. The temperature of the sample was continuously measured with a thermocouple which simultaneously served as a pendulum mounting. The temperature of the permanent magnet was assumed to be constant.

[0095] As soon as the Curie temperature of the sample material had been exceeded due to the heating with hot air, the sample material lost its magnetic properties and the pendulum returned to its rest position since it was no longer influenced by the permanent magnet. The temperature profile over time tin minutes for sample M1 is shown in FIG. 9. The temperature of sample M1 initially increased continuously up to 388 C. at which point it fell abruptly to 381 C. and then rose to 382 C. again. The influence of the permanent magnet on the sample and the contact between the pendulum and the permanent magnet were lost at this point. The sample is under the influence of the permanent magnet in region 15 shown in the figure; this is not the case in region 16 shown in the figure. The abrupt temperature change is attributable to the magnetocaloric effect which occurs as soon as the Curie temperature is reached. The Curie temperature of sample M1 was thus determined as approximately 388 C.

[0096] Disengagement of the pendulum from the permanent magnet in this manner is successful when the Curie temperature of the sample material is approximately between 350 C. and 400 C. Sample M2 could not be disengaged from the permanent magnet by supplying heat as described and the Curie temperature of sample M2 was determined as 540 C. by alternative methods of measurement.

[0097] Sample M3 showed no magnetic properties toward the permanent magnet and was not attracted to the permanent magnet.

[0098] The Curie temperature of sample M2 was quantitatively determined by thermogravimetric analysis using a permanent magnet, dynamic differential calorimetry and a high-frequency inductance measurement.

[0099] Depending on the manner of production, the three samples M1, M2 and M3 exhibited different magnetic properties. It was possible to influence the Curie temperature of the solids produced. Furthermore, M1 and M2 were calcined again at a higher temperature which made it possible to influence the Curie temperatures. The reduction in the Curie temperature achieved by calcining resulted from restructuring processes in the sample.

Comparative Example 1 Production of Aniline

[0100] The production of aniline from nitrobenzene is carried out using a copper catalyst as described in WO 2010/130604 A2 for example. The exothermic reaction is carried out in a fluidized-bed reactor with internal heat exchanger. A fluid comprising hydrogen as reactant flows through the fluidized bed. The nitrobenzene is injected into the fluidized bed in liquid form. Heat transfer is the limiting factor when the reaction is carried out in this way.

Example 4 Production of Aniline

[0101] The reaction is carried out as in comparative example 1, but a magnetically enhanced fluidized bed is employed in place of a fluidized-bed reactor with internal heat exchanger and the catalyst is comprised in magnetic catalyst particles. The Curie temperature Tc of the magnetic catalyst particles is 350 C. When the magnetic particles have a temperature lower than their Curie temperature, the magnetic particles are localized in the fluidized bed with the aid of an applied magnetic field. When the magnetic particles in the fluidized bed are heated to a temperature higher than their Curie temperature, the magnetic particles are discharged from the fluidized bed with the fluid phase. This discharges heat and catalyst mass from the fluidized bed with the magnetic particles. Here, the amount of heat discharged is self-regulating since more heat is discharged the more magnetic particles are heated to a temperature higher than their Curie temperature Tc.

LIST OF REFERENCE NUMERALS

[0102] 1 first fluidized bed

[0103] 1a second fluidized bed

[0104] 1b third fluidized bed

[0105] 1c fourth fluidized bed

[0106] 2 first portion of magnetizable and/or magnetic particles at a temperature Tp2 lower than the Curie temperature Tc of the particles

[0107] 3 second portion of magnetizable and/or magnetic particles at a temperature Tp3 higher than the Curie temperature Tc of the particles

[0108] 4 fluid phase

[0109] 5 magnet coil

[0110] 6 reactor wall

[0111] 7 flow direction of the fluid phase 4

[0112] 8 direction of movement of the second portion 3 of the magnetizable and/or magnetic particles

[0113] 9 magnet coil for generating an alternating magnetic field

[0114] 10 stirrer

[0115] 11 direction of movement of the first portion 2 of the magnetizable and/or magnetic particles

[0116] 12 heating element

[0117] 13 cooling jacket

[0118] 14 heating jacket

[0119] 15 region in which the sample is under the influence of the permanent magnet

[0120] 16 region in which the sample is not under the influence of the permanent magnet

[0121] 19 graph for sample M3

[0122] 20 graph for sample M2

[0123] 21 feed line

[0124] 22 gravitational force

[0125] 23 grid

[0126] 24 downpipe

[0127] 25 riser pipe

[0128] 26 magnet coil for generating magnetic fields of a magnetic conveying system

[0129] 27 first batch reactor

[0130] 27a second batch reactor

[0131] 27b third batch reactor

[0132] X conversion of nitrobenzene in [%]

[0133] t time in [h]