Reactor and method for carrying out a photochemical reaction using the reactor - Patents.com

Abstract

The invention is based on a reactor (10) comprising a reaction vessel (12) for receiving at least one medium. It is proposed that the reactor (10) comprises an external radiation unit (14) arranged outside the reaction vessel (12), the external radiation unit (14) having at least one external radiation element (16, 48, 52) for irradiating the medium in the reaction vessel (12).

Description

[Technical field]

[0001] The present invention relates to a reactor according to the preamble of claim 1 and to a method for carrying out a photochemical reaction using a reactor according to the preamble of claim 15. [Background technology]

[0002] Reactors comprising a reaction vessel for receiving a medium are already known from the prior art. In order to carry out a photochemical reaction in the reaction vessel, for example for the depolymerization of plastics or for the chlorination of polyvinylchlorid (PVC) to produce PVC-C, irradiation of the medium with electromagnetic radiation, for example UV radiation, is required. In the known reactors, multiple radiation sources for supplying the electromagnetic radiation are arranged in the reaction vessel. This can lead to disadvantages for the implementation of the method, for example because the size or configuration of the stirrer is limited due to the multiple internal radiation sources arranged in the reaction vessel and / or because the operating pressure is limited by the pressure resistance of the multiple internal radiation sources, resulting in a reduced efficiency of conventional reactors for a large number of photochemical reactions. Summary of the Invention [Problem to be solved by the invention]

[0003] The object of the present invention is to provide a universal device having advantageous properties, in particular with regard to efficiency. This object is achieved according to the invention by the features of claims 1 and 15, advantageous configurations and developments of the invention being set out in the dependent claims. [Means for solving the problem]

[0004] The present invention relates to a reactor comprising a reaction vessel for receiving at least one medium. It is proposed that the reactor comprises an external radiation unit arranged outside the reaction vessel, the external radiation unit having at least one external radiation element for irradiating the medium in the reaction vessel.

[0005] Such an implementation advantageously makes it possible to provide a reactor with improved efficiency. In particular, an efficient process control is achievable and the volume of the reaction vessel can be utilized particularly efficiently. Furthermore, advantageously, a particularly high adaptability is achievable. In particular, it is possible to use a wide variety of stirrers in the reaction vessel, depending on the type of chemical reaction taking place in the reaction vessel and the reactants used in said reaction, respectively the products produced by said reaction.

[0006] By "reactor" is meant in particular a functioning component, in particular a structural and / or functional component, of a reactor, in particular a photoreactor. The reactor may comprise the entire reactor. Preferably, the reactor is realised as a photoreactor. The reactor and / or reactor comprising the reactor is configured, but is not limited to, for carrying out photochemical reactions, for example for the depolymerisation of plastics or for the chlorination of polyvinylchlorid (PVC) to form PVC-C or for the photoinitiated polymerization of monomers into synthetic resins and / or adhesives.

[0007] The reaction vessel comprises a vessel bottom and at least one side wall, which together form an interior vessel space for receiving at least one medium. Preferably, the vessel bottom and the side wall are implemented integrally. "Integral" means that they are connected by a material bond, such as, for example, a welding process and / or a bonding process, and particularly advantageously are formed, for example, by production from a casting and / or by production in a one-component or multi-component injection molding procedure. The vessel bottom and the side wall are preferably made of metal and / or metal alloy, for example titanium or stainless steel. Alternatively, it is also conceivable that the vessel bottom and the side wall are made of glass, for example borosilicate glass or quartz glass, or plastic, for example polyetheretherketone (PEEK). The reaction vessel, in particular the vessel bottom and the side wall, may be implemented in a double-walled manner. The reaction vessel may have a rectangular shape in plan view. Preferably, the reaction vessel may have an oval shape in plan view, for example a circular or elliptical shape. Preferably, the reaction vessel comprises at least one connection unit with at least one connection element, which is adjacent to the side wall in the upper region, in particular integrally mounted with the side wall. The vessel interior space may be particularly gas-tightly closable, for example by a cover of the connection unit. Alternatively or additionally, it is also conceivable that a reactor and / or further units of the reactor including the reactor may be coupled to the reaction vessel by a connection unit. For example, a fume hood and / or a mixing unit and / or an input line and / or an output line may be coupled to the reaction vessel by a connection unit. Preferably, the reaction vessel is configured for an operating pressure of at least 5 bar, although operation of the reaction vessel at lower operating pressures is of course also conceivable. The reaction vessel may in particular be configured for vacuum applications with very low operating pressures of less than 1 bar. The reaction vessel is not limited to receiving a particular type of medium, but is preferably configured to receive a wide variety of media, which may in particular be solid and / or liquid and / or gas.

[0008] The external radiation unit includes at least one external radiation element and may further include at least one further external radiation element. The radiation element is configured to provide electromagnetic radiation for irradiation of the medium in the reaction vessel. The electromagnetic radiation provided by the external radiation element may be, for example, infrared radiation and / or visible light and / or ultraviolet radiation. Preferably, the radiation provided by the radiation element is ultraviolet radiation. The electromagnetic radiation provided by the external radiation element may be polychromatic. Preferably, the electromagnetic radiation provided by the external radiation element is monochromatic. The wavelength of the electromagnetic radiation provided by the external radiation element may be adapted and / or adaptable to the type of chemical reaction(s) occurring in the reaction vessel, for example, but not limited to, 365 nm or 385 nm or 395 nm or 405 nm or 420 nm or 460 nm or 525 nm or 592 nm or 625 nm. Preferably, the radiation intensity that can be provided by the external radiation element is adjustable, in particular steplessly adjustable. Preferably, the external radiation element is replaceable, in particular without tools. The external radiation element comprises at least one radiation source, which may be implemented, for example, but not exclusively, as an LED and / or as a mercury lamp and / or as an excimer lamp and / or the like. Preferably, the radiation source of the external radiation element is configured as an LED. In a particularly advantageous embodiment, the at least one external radiation element is implemented as an explosion-proof external radiation element, in particular comprising at least one explosion-proof LED as radiation source. Preferably, the explosion-proof external radiation element is certified according to ATEX and / or IECEx. Such an embodiment advantageously makes it possible to provide the reactor for safe use in areas at risk of explosion. The at least one external radiation element and the further external radiation element of the external radiation unit may be implemented to be at least substantially identical to each other.It is also conceivable that the at least one external radiating element and the at least one further external radiating element differ with respect to at least one parameter, for example with respect to the type and / or dimensions of the radiation source for supplying the electromagnetic radiation and / or with respect to the wavelength and / or the radiation intensity of the supplied electromagnetic radiation.

[0009] As used herein, numerical terms such as, for example, "first" and "second" preceding certain terms merely serve to distinguish between and / or assign objects to one another, and do not imply a total number and / or order in which the objects exist. In particular, a "second object" does not necessarily imply the existence of a "first object."

[0010] "At least substantially" is to be understood here as a deviation from a given value, in particular of less than 25%, preferably less than 10% and particularly preferentially less than 5% of the given value.

[0011] "Configured" means specially designed and / or equipped. By an object being configured for a particular function, it should be understood that the object will perform and / or execute this particular function in at least one application and / or operational state.

[0012] It is further proposed that the reactor comprises an internal radiation unit arranged in the reaction vessel, the internal radiation unit having at least one internal radiation element for irradiation of the medium. This advantageously allows for further improvement of the efficiency. In particular, the photon density in the reaction vessel can be increased and the quantum yield of the radiation-induced chemical process in the reaction vessel can be improved. The internal radiation element is configured to provide electromagnetic radiation, for example infrared radiation and / or visible light and / or ultraviolet radiation, for irradiation of the medium in the reaction vessel in addition to the at least one external radiation element of the external radiation unit. The wavelength and / or wavelength range and / or radiation intensity of the electromagnetic radiation provided by the internal radiation element may correspond to the electromagnetic radiation provided by the at least one external radiation element. It is also conceivable that the at least one external radiation element and the at least one internal radiation element differ with respect to at least one parameter, for example with respect to the type and / or dimensions of the radiation source for providing the electromagnetic radiation and / or with respect to the wavelength and / or radiation intensity of the electromagnetic radiation provided. For example, the internal radiation element can be configured to emit pulsed radiation. The internal radiation element comprises at least one radiation source, which may be implemented, for example, but not limited to, as an LED and / or a mercury lamp and / or an excimer lamp and / or the like. In a particularly advantageous implementation, the internal radiation element is implemented as an explosion-proof internal radiation element, in particular comprising at least one explosion-proof LED as radiation source. Preferably, the explosion-proof internal radiation element is certified according to ATEX and / or IECEx. This advantageously makes it possible to provide the reactor for safe use in areas at risk of explosion. Preferably, the radiation intensity that can be provided by the internal radiation element is in particular steplessly adjustable. This advantageously allows for a precise adjustment of the desired radiation intensity, thus achieving a particularly flexible adaptation to different photochemical reactions. Preferably, the internal radiation element comprises a jacket tube (Mantelrohr) which is transparent to electromagnetic radiation and in which the at least one radiation source is arranged, in particular to protect it from influences by the medium in the reaction vessel.The jacket tube may be made, for example, from quartz glass or borosilicate glass. It is conceivable that the jacket tube comprises an optical filter, such as a gradient filter and / or an edge filter and / or a polarizing filter, for modification of the electromagnetic radiation provided by the internal radiation element. In addition to the at least one internal radiation element, the internal radiation unit may comprise at least one further internal radiation element. The at least one internal radiation element and the further internal radiation element of the internal radiation unit may be implemented to be at least substantially identical to each other. It is also conceivable that the at least one internal radiation element and the at least one further internal radiation element differ with respect to at least one parameter, for example with respect to the type and / or dimensions of the radiation source for providing the electromagnetic radiation and / or with respect to the wavelength and / or radiation intensity of the electromagnetic radiation provided. The internal radiation unit may be fixedly installed in the reaction vessel. Preferably, the internal radiation unit is removably fixed in the reaction vessel, in particular by means of a connection unit. This advantageously allows the reactor to be operated with or without the internal radiation unit as required, thus further increasing the adaptability.

[0013] The reaction vessel may be implemented to be partially or completely transparent and transparent to electromagnetic radiation. However, in an advantageous embodiment, it is proposed that the reaction vessel comprises at least one irradiation window transparent to electromagnetic radiation, and at least one external radiation element is arranged around the irradiation window. Preferably, in the mounted state, the irradiation window is oriented vertically and has a vertical extent extending perpendicular to the vessel bottom and a horizontal extent extending parallel to the vessel bottom. The vertical and horizontal extents of the irradiation window may have substantially the same size. However, preferentially, the vertical extent of the irradiation window is in particular at least two times, advantageously at least three times, particularly advantageously at least four times, preferably at least five times and particularly preferentially at least six times larger than the horizontal extent of the irradiation window. This advantageously allows a particularly selective and efficient irradiation of the medium. Preferably, the external radiation element is arranged around the radiation window such that the electromagnetic radiation generated by the external radiation element can enter the reaction vessel at least partially through the radiation window, in particular at least 60%, advantageously at least 70%, particularly advantageously at least 80%, preferably at least 90%, particularly preferentially at least 95%. Optical filters, such as gradient filters and / or edge filters and / or polarizing filters and / or the like, can be arranged on the radiation window for modification of the electromagnetic radiation provided by the external radiation element. It is also conceivable that the reactor comprises at least one heating element and / or at least one cooling element for heating and / or cooling the radiation window. The heating element and / or the cooling element may be arranged on the radiation window or may be integrated in the radiation window. The reaction vessel may comprise a plurality of radiation windows. Preferably, the number of radiation windows corresponds to the number of external radiation elements of the external radiation unit. Preferentially, the reaction vessel has three radiation windows, which are arranged offset from one another in the circumferential direction of the reaction vessel. However, alternatively, reaction vessels with less than three or more than three radiation windows are also conceivable. Preferably, the total window surface area, transparent to electromagnetic radiation, of all irradiation windows of the reactor corresponds to a maximum of 10% of the lateral surface area of ​​the reaction vessel.The external radiation unit may be configured to irradiate the entire internal vessel space of the reaction vessel through the irradiation window. In an advantageous embodiment, however, the external radiation unit is configured for partial irradiation of the vessel internal space, and the one or more irradiation windows are arranged in such a way that in the operating state of the reactor, at least one first partial area of ​​the vessel internal space is irradiated by the external radiation unit and at least one second partial area of ​​the vessel internal space is not irradiated. In this embodiment, if the reactor is operated without an additional internal radiation unit, a partial volume of the medium that is in motion in the operating state, in particular by the mixing unit of the reactor, passes alternately between partial areas that are irradiated and partial areas that are not irradiated into the vessel internal space, thereby receiving a partial irradiation that is in particular comparable to a pulsed irradiation. Such an embodiment is particularly suitable for a very efficient development of photochemical reactions with low photon requirements, for example for chlorination, where permanent irradiation of the medium is not necessarily required. It is therefore advantageously possible to obtain a particularly high quantum yield and to further improve the efficiency. Preferably, in areas outside the irradiation window, the reaction vessel is not transparent to electromagnetic radiation, in particular embodied as UV radiation and / or visible light and / or infrared radiation. This advantageously allows for an increased operational safety in the operation of the reactor, since the danger to humans and / or the risk of damaging objects around the reaction vessel caused by electromagnetic radiation is reduced, preferably minimized.

[0014] The irradiation window can be arranged, for example, in the cover or in the bottom of the reaction vessel. However, in a particularly advantageous embodiment, it is proposed that the irradiation window is arranged in the side wall of the reaction vessel. Such an implementation advantageously makes it possible to achieve a particularly selective irradiation of the medium, thus further improving the efficiency.

[0015] It is further proposed that the external radiation element comprises at least one LED. This advantageously allows to further improve the efficiency, in particular the energy efficiency, of the reactor. In particular, it is possible to provide a cost-effective external radiation unit. Preferably, the external radiation element comprises a high-performance LED array with a power of at least 75 watts. In another advantageous embodiment, it is proposed that the external radiation element comprises a mercury lamp. This advantageously allows to further improve the efficiency, since a particularly high radiation intensity can be provided. The mercury lamp has a power of at least 500 watts, advantageously at least 600 watts, particularly advantageously at least 700 watts, preferably at least 800 watts, particularly preferentially at least 900 watts. The external radiation unit may comprise only external radiation elements with LEDs or only external radiation elements with mercury lamps. It is also conceivable that at least one external radiation element has an LED and at least one other external radiation element has a mercury lamp. Alternatively or additionally, it is also conceivable that at least one external radiation element of the external radiation unit comprises a different type of radiation source, for example an excimer lamp.

[0016] It is further proposed that the reactor has a mixing unit for mixing the medium, which generates an increased mixing rate relative to the average mixing rate in the vicinity of the irradiation window. Such an implementation advantageously allows to further improve the efficiency of the reactor. The mixing unit comprises at least one mixing element configured to move the medium in the reaction vessel for mixing. The mixing unit may include at least one mixing element implemented as a pump. Preferably, the mixing unit includes at least one mixing element implemented as a stirring element. The mixing unit is preferentially designed for mixing highly viscous media, in particular media having a dynamic viscosity of at least 1,000 mPa·s, advantageously at least 10,000 mPa·s, particularly advantageously at least 20,000 mPa·s, preferably at least 40,000 mPa·s, particularly preferentially at least 50,000 mPa·s. The mixing unit is designed in particular to mix highly viscous media having a dynamic viscosity of up to 1,000,000 mPa·s. In the operating state of the reactor, the mixing unit sets in motion the medium in the reaction vessel, which medium has different speeds, in particular flow speeds and / or shear rates, in different partial regions of the reactor. The mixing speed in a partial region of the stirred vessel is characterized by the average speed of the medium in the partial region, in particular the average flow speed and / or shear rate. The average mixing speed of the medium is therefore characterized by the speed of the medium averaged over the entire volume of the reaction vessel. Preferably, the mixing unit produces a mixing speed in the vicinity of the irradiation window that is increased by at least 5%, advantageously at least 10%, particularly advantageously at least 15%, preferably at least 20%, particularly preferentially at least 25% with respect to the average mixing speed. Preferably, the vicinity has the shape of an imaginary hollow cylinder, the width of which is the distance starting from the inner wall of the reaction vessel and extending perpendicularly to the inner wall, and which corresponds to at least 10% of the inner diameter of the reaction vessel, and the height of which extends from the vessel bottom to at least the upper edge of the irradiation window.

[0017] It is further proposed that the reactor comprises at least one wall-proximate scraper arranged in the reaction space for removing deposits of the medium on the inner wall of the reaction vessel. Such an implementation advantageously makes it possible to further improve the efficiency of the reactor. In particular, it is possible to achieve that the at least one irradiation window is free of medium deposits, so that the intensity of the irradiation of the medium by the external radiation element through the irradiation window can be kept substantially constant over a desired period of time. It is further proposed that the scraper has the shape of a planar elliptical ring segment. Such an implementation advantageously makes it possible to achieve a particularly efficient removal of deposits. In particular, a particularly favorable adaptation to the inner contour of the reaction vessel is achievable if the scraper has the shape of a planar elliptical ring segment. Preferably, the reactor comprises at least one further wall-proximate scraper arranged in the reaction space for removing deposits of the medium on the inner wall of the reaction vessel. Preferably, the further wall-proximate scraper is implemented at least substantially identically to the wall-proximate scraper and is arranged on the rotation axis of the mixing unit offset by 180° from the wall-proximate scraper, in particular arranged so that the wall-proximate scraper is movable into the further wall-proximate scraper by a rotation of 180° about the rotation axis. Preferably, the wall-proximate scraper and any further wall-proximate scrapers present are assigned to the mixing unit.

[0018] The wall-proximate scrapers may be oriented parallel to the axis of rotation of the mixing unit. However, in an advantageous embodiment, it is proposed that the wall-proximate scrapers are oriented at an angle to the axis of rotation of the mixing unit. This advantageously allows to further improve the efficiency. Preferably, the scrapers are oriented at an angle to the axis of rotation of the mixing unit such that the main direction of extension of the wall-proximate scrapers includes an acute angle of inclination with the axis of rotation, in particular between 20° and 80°, advantageously between 35° and 75°, preferentially between 40° and 70°. By "main direction of extension" of an object is to be understood in this document the direction that extends parallel to the longest side of the smallest rectangle that still completely surrounds the object.

[0019] It is further proposed that the distance of the wall-proximate scraper from the inner wall amounts to a maximum of 10% of the inner diameter of the reaction vessel. Such an embodiment advantageously allows for a further improvement in the efficiency with regard to the removal of deposits of medium on the inner wall of the reaction vessel. In particular, the distance of the wall-proximate scraper from the inner wall is at most 9%, advantageously at most 8%, particularly advantageously at most 7%, preferably at most 6%, particularly preferentially at most 5% of the inner diameter of the reaction vessel.

[0020] In addition to this, it is proposed that the reactor comprises a drive unit with a drive shaft for driving the wall-proximate scraper, the drive unit being coupled to the drive shaft only in the lower region via the web (Steg) of the drive unit. Such an implementation advantageously allows for a further improvement in efficiency, in particular since a particularly efficient utilization of the internal vessel space of the reaction vessel is made possible. Furthermore, it is proposed that the internal radiation source is arranged at least partially between the wall-proximate scraper and the drive shaft. This advantageously allows for a further improvement in efficiency, in particular since a particularly efficient utilization of the internal vessel space of the reaction vessel is made possible. Furthermore, it advantageously allows for efficient irradiation also in the outer region in the vicinity of the irradiation window, which cannot be reached sufficiently or at all by the electromagnetic radiation provided by the external radiation unit. Preferably, in the operating state, at least one internal radiation element is stationarily arranged in the reaction vessel at least partially between the wall-proximate scraper and the drive shaft, and the at least one wall-proximate scraper rotates around the internal radiation element in the reaction vessel without contacting the internal radiation element. Alternatively, it is conceivable that the wall-proximate scraper is additionally connected to the drive shaft in the upper region via a further web. In a further alternative embodiment, it is conceivable that the wall-proximate scraper and the further wall-proximate scraper are connected to each other in the upper region by a ring, and the internal radiation source may be arranged at least partially between the ring and the drive shaft.

[0021] The invention further relates to a reactor, in particular a photoreactor, comprising a reactor according to one of the above-mentioned embodiments, which is distinguished in particular by the above-mentioned advantageous features of the reactor.

[0022] The invention is further based on a method for carrying out a photochemical reaction using a reactor comprising a reaction vessel for receiving at least one medium, in particular a reactor according to one of the above-mentioned embodiments.

[0023] It is proposed that the medium in the reaction vessel is irradiated by an external radiation unit having at least one external radiation element arranged outside the reaction vessel. Such an embodiment advantageously makes it possible to provide a particularly efficient and adaptable method for carrying out photochemical reactions.

[0024] The reactor according to the invention is not limited herein to the applications and embodiments described above, in particular, to achieve the functions described herein, the reactor according to the invention may comprise a different number of individual elements, components and units than given herein. [Brief description of the drawings]

[0025] Further advantages will become apparent from the following description of the drawings, in which exemplary embodiments of the invention are shown. The drawings, the specification and the claims contain a number of combinations of features, which a person skilled in the art will consider individually and in a deliberate manner and will find further suitable combinations. [Figure 1] FIG. 1 is a schematic perspective view of a reactor with a reaction apparatus including a reaction vessel and an external radiation unit. [Diagram 2] FIG. 2 is a schematic diagram of a reactor comprising a drive unit, a mixing unit and an internal radiation unit. [Diagram 3] FIG. 3 is a schematic flow chart of a method for conducting a photochemical reaction using a reactor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] 1 shows in a schematic perspective view a reactor 50. The reactor 50 is implemented as a photoreactor. The reactor 50 comprises the reactor 10 implemented as a photoreactor. The reactor 10 comprises a reaction vessel 12. The reaction vessel 12 is configured to receive at least one medium (not shown). The reaction vessel 12 has a vessel bottom 54 and a circumferential side wall 24 adjacent to the vessel bottom 54. The vessel bottom 54 and the side wall 24 are integrally mounted and together form a vessel interior space 56. The reaction vessel 12 comprises a connection unit 58 adjacent to the side wall 24 in an upper region. By means of the connection unit 58, the vessel interior space 56 can be closed in a pressure-tight manner, for example by means of a cover (not shown), or further units, for example the drive unit 40 of the reactor 10 (see FIG. 2) or a fume hood (not shown), can be coupled to the reaction vessel 12.

[0027] The reactor 10 comprises an external radiation unit 14 arranged outside the reaction vessel 12. In this case, the external radiation unit 14 is arranged outside the reaction vessel 12 and outside the vessel interior space 56. The external radiation unit 14 comprises at least one external radiation element 16 for irradiating the medium in the reaction vessel 12. In this case, the external radiation unit 14 comprises a total of three external radiation elements, namely the external radiation element 16 and two further external radiation elements 48, 52. However, alternatively, a smaller or larger number of external radiation elements is conceivable. The external radiation element 16 and the further external radiation element 52 each comprise an LED (not shown). The external radiation element 48 comprises a mercury lamp (not shown).

[0028] The reaction vessel 12 comprises at least one irradiation window 22. The irradiation window 22 is arranged on a side wall 24 of the reaction vessel 12. The irradiation window 22 is transparent to electromagnetic radiation. The external radiation element 16 is arranged around the irradiation window 22, i.e. outside the vessel interior space 56. In this case, the reaction vessel 12 comprises two further irradiation windows 64, 66, which are also arranged on the side wall 24 of the reaction vessel 12 and are implemented to be at least substantially identical to the irradiation window 22. The further external radiation element 48 is arranged around the further irradiation window 64 outside the vessel interior space 56. The further external radiation element 52 is arranged around the further irradiation window 66 outside the vessel interior space 56.

[0029] In the operating state of the reactor 10, the medium in the vessel interior space 56 is irradiated with electromagnetic radiation, for example ultraviolet light. In the operating state, the electromagnetic radiation is generated by the external radiating element 16 and the further external radiating elements 48, 52 and enters the vessel interior space 56 via the irradiation window 22 and via the further irradiation windows 64, 66, respectively, and impinges on the medium in the vessel interior space 56.

[0030] FIG. 2 shows the reactor 10 in a highly simplified schematic view. The reactor 10 comprises a mixing unit 26 for mixing the medium. The mixing unit 26 is arranged in the reaction vessel 12, i.e. in the vessel interior space 56. The mixing unit 26 comprises a stirring element 60. In the operating state of the reactor 10, when mixing the medium, the stirring element 60 rotates around the rotation axis 34 of the mixing unit 26. Here, the mixing unit 26, in particular by means of the stirring element 60, generates an increased mixing rate with respect to the average mixing rate in the vicinity 28 of the irradiation window 22. The medium has an increased velocity in the vicinity 28 with respect to the average velocity. Thus, in the operating state of the reactor 10, the residence time of individual particles of the medium in the vicinity 28 is short, so that excessive irradiation by the electromagnetic radiation supplied by the external radiation unit 14, which could cause undesired side reactions, is prevented. Similarly, the mixing unit 26 also generates an increased mixing rate with respect to the average mixing rate in the further vicinity (not shown) of further irradiation windows 64, 66.

[0031] The reactor 10 comprises a wall-proximate scraper 30 disposed within the reactor vessel 12. The wall-proximate scraper 30 is configured to remove deposits of medium on an inner wall 32 of the reactor vessel 12. The distance 36 of the wall-proximate scraper 30 from the inner wall 32 is at most 10% of the inner diameter 38 of the reactor vessel 12. The wall-proximate scraper 30 has the shape of an elliptical ring segment. The wall-proximate scraper 30 is oriented at an angle to the rotation axis 34 of the mixing unit 26. In this case, the wall-proximate scraper 30 is oriented at an inclination angle of about 45° to the rotation axis 34, although larger or smaller inclination angles are also conceivable.

[0032] The reactor 10 comprises a further wall-proximate scraper 62, which is implemented substantially identically to the wall-proximate scraper 30 and likewise has the shape of an elliptical ring segment. The further wall-proximate scraper 62 is arranged on the opposite side of the rotation axis 34 to the wall-proximate scraper 30. The further wall-proximate scraper 62 also has a distance 36 from the inner wall 32 of the reactor vessel 12 and is oriented at an angle to the rotation axis 34, or at an inclination angle of about 45°. In a virtual rotation of 180° in the direction of rotation 68 about the rotation axis 34, the wall-proximate scraper 30 and the further wall-proximate scraper 62 can be displaced from each other.

[0033] In this case, the scraper 30 and the further scraper 62 are in each case part of the mixing unit 26 and, in addition to removing deposits of the medium on the inner wall 32 of the reaction vessel 12, also help to mix the medium. In the operating state of the reactor 10, the wall-proximate scraper 30 and the further wall-proximate scraper 62 rotate in a rotation direction 68 around the rotation axis 34 in proximity to the inner wall 32 and thus remove deposits from the inner wall 32. In addition to the inner wall 32, the irradiation window 22, the further irradiation window 64 (see FIG. 1) and the further irradiation window 66 are also cleaned of deposits of the medium by the wall-proximate scraper 30 and the further wall-proximate scraper 62, so that the electromagnetic radiation provided by the external radiation unit 14 can enter the vessel inner space 56 through the irradiation windows 22, 64, 66 almost unhindered. In Fig. 2 a clockwise operation of the mixing unit 26 is shown, in which the scraper 30 and the further scraper 62 rotate around the rotation axis 34 in a rotation direction 68 and thus convey the medium from bottom to top. The mixing unit 26 is also configured for a counterclockwise operation (not shown), in which the scraper 30 and the further scraper 62 rotate around the rotation axis 34 opposite to the rotation direction 68 shown in Fig. 2 and thus convey the medium from top to bottom. In the operating state, a change between clockwise and counterclockwise operation can be provided in order to achieve further improved removal of deposits of the medium, in particular on the irradiation window 22, 64, 66 and / or the inner wall 32, and / or to avoid deposits of the medium in several partial regions of the vessel inner space 56.

[0034] The reactor 10 comprises a drive unit 40. The drive unit 40 comprises a drive shaft 42 for driving the scraper 30 and the further scraper 62. The scraper 30 is connected to the drive shaft 42 only in a lower region 44 via a web 46 of the drive unit 40. The further scraper 62 is present only in a further lower region (not shown) which is connected to the drive shaft 42 via a web 46 of the drive unit 40. The web 46 is connected to the drive shaft 42 via a hub (nabe).

[0035] The drive unit 40 is further configured to drive the mixing unit 26. In operation, the drive shaft 42 rotates about the axis of rotation 34 and thus drives the scraper 30, the further scraper 62 and the stirring element 60 for a rotational movement about the axis of rotation 34.

[0036] The reactor 10 comprises an internal radiation unit 18. The internal radiation unit 18 is arranged in the reaction vessel 12. The internal radiation unit 18 comprises at least one internal radiation element 20 for irradiating the medium. The internal radiation element 20 has at least one LED (not shown), which is arranged in a transparent protective tube, for example made of glass. In this case, the internal radiation unit 18 comprises a further internal radiation element 70 for irradiating the medium. The further internal radiation element 70 is implemented substantially identically to the internal radiation element 20. The internal radiation element 20 is arranged at least partially between the wall-proximate scraper 30, the further wall-proximate scraper 62 and the drive shaft 42. The further internal radiation element 70 is also arranged at least partially between the wall-proximate scraper 30, the further wall-proximate scraper 62 and the drive shaft 42, but on the opposite side of the drive shaft 42 to the internal radiation element 20. The internal radiation element 20 and the further internal radiation element 70 are arranged stationary in the reaction vessel 12. In an operating state of the reactor 10, the wall proximate scraper 30 and the further wall proximate scraper 62 rotate in a rotational direction 68 around the inner radiating element 20 and the further inner radiating element 70 without contacting the inner radiating elements 20,70.

[0037] Alternatively, the reactor 10 can be embodied without the internal radiation unit 18 and can have only an external radiation unit 14 for irradiating the medium. 3 shows a schematic process flow diagram of a method for conducting a photochemical reaction using a reactor 10 including a reaction vessel 12 for receiving at least one medium. The method includes at least two method steps 72, 74. In a first method step 72 of the method, at least one medium is placed in the reaction vessel 12. In a second method step 74 of the method, the medium is irradiated in the reaction vessel 12 by an external radiation unit 14 arranged outside the reaction vessel 12. [Explanation of symbols]

[0038] 10. Reactor 12...Reaction vessel 14…External radiation unit 16…External radiating element 18…Internal radiation unit 20…Internal radiating element 22...Irradiation window 24…Side wall 26…Mixed unit 28...Nearby 30…Scraper 32…Inner wall 34…Rotation axis 36…distance 38…Inner diameter 40…Drive unit 42…Drive shaft 44…Lower area 46…Web 48…External radiating element 50…Reactor 52…External radiating element 54…Container bottom 56…Container internal space 58…Connection unit 60...Mixing element 62…More scrapers 64…Further irradiation window 66…Further irradiation window 68…Rotation direction 70…further internal radiating elements 72...First method step 74...Second method step

Claims

1. A reactor (10) comprising a reaction vessel (12) for receiving at least one medium, the reactor (10) comprising an external radiation unit (14) arranged outside the reaction vessel (12), the external radiation unit (14) having at least one external radiation element (16, 48, 52) for irradiating the medium in the reaction vessel (12).

2. 2. The reactor (10) of claim 1, further comprising an internal radiation unit (18) arranged in the reaction vessel (12), the internal radiation unit (18) having at least one internal radiation element (20, 70) for irradiating the medium.

3. 2. The reactor (10) of claim 1, wherein the reaction vessel (12) includes at least one irradiation window (22, 64, 66) that is transparent to electromagnetic radiation, and the at least one external radiating element (16, 48, 52) is arranged around the irradiation window (22, 64, 66).

4. 4. The reactor (10) of claim 3, wherein the irradiation window (22, 64, 66) is located on a side wall (24) of the reaction vessel (12).

5. 2. The reactor (10) of claim 1, wherein the external radiating element (16, 52) comprises at least one LED.

6. 2. The reactor (10) of claim 1, wherein said external radiating element (48) comprises at least one mercury lamp.

7. 2. The reactor (10) according to claim 1, further comprising a mixing unit (26) for mixing the medium, the mixing unit (26) producing an increased mixing rate relative to the average mixing rate in the vicinity (28) of the irradiation window (22, 64, 66) of the reactor vessel (12).

8. 2. The reactor (10) of claim 1, further comprising at least one wall-proximate scraper (30, 62) disposed within the reactor (12) for removing deposits of the medium on the interior wall (32) of the reactor (12).

9. 9. The reactor (10) of claim 8, wherein the wall-proximate scraper (30, 62) has the shape of a planar elliptical ring segment.

10. 9. The reactor (10) of claim 8, wherein the wall-proximate scraper (30, 62) is oriented at an angle to the axis of rotation (34) of a mixing unit (26) for mixing the medium.

11. 9. The reactor (10) of claim 8, wherein the distance (36) of the wall-proximate scraper (30, 62) from the inner wall (32) is at most 10% of the inner diameter (38) of the reactor vessel (12).

12. 9. The reactor (10) according to claim 8, characterized in that the reactor (10) comprises a drive unit (40) having a drive shaft (42) for driving the wall-adjacent scraper (30, 62), the wall-adjacent scraper (30, 62) being coupled to the drive shaft (42) only in a lower region (44) via a web (46) of the drive unit (40).

13. The reactor (10) comprises an internal radiation unit (18) disposed within the reaction vessel (12), the internal radiation unit (18) has at least one internal radiation element (20, 70) for irradiating the medium; 13. The reactor (10) of claim 12, wherein the internal radiating element (20) is at least partially disposed between the wall-proximate scraper (30, 62) and the drive shaft (42).

14. A reactor (50), in particular a photoreactor, comprising a reactor (10) according to any one of claims 1 to 13.

15. 1. A method for carrying out a photochemical reaction using a reactor (10) comprising a reaction vessel (12) for receiving at least one medium, characterized in that the medium in the reaction vessel (12) is irradiated by an external radiation unit (14) arranged outside the reaction vessel (12) using at least one external radiation element (16, 48, 52).

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