Apparatus and method for purifying a process gas containing at least one pollutant gas

Abstract

The present invention relates to an apparatus for purifying a process gas (22) containing at least one contaminant gas, comprising a reactor vessel designed as a centrifuge, having a cylindrical region (5) and a converging region (9), wherein oxygen or oxygen-containing gas is introduced as a reactant gas (21) into at least one gas inlet (1, 2, 3) disposed on the cylindrical region (5), and discharged through at least one gas outlet (10, 11) disposed on the converging region (9). The apparatus further includes a contaminant gas inlet (8) disposed on the cylindrical region (5), and designed to introduce a defined volumetric flow rate of the process gas (22) containing at least one contaminant gas into the reactor vessel.

Description

Apparatus and method for purifying a process gas containing at least one contaminant gas The present invention relates to an apparatus and method for cleaning a process gas containing at least one contaminant gas. Various chemical processes produce flammable and / or toxic gases, which, among other things, contribute to global warming. However, due to their hazardous properties, they generally require costly treatment and, as far as possible, rendering them harmless. Various solutions are known in the prior art: DE 20 2005 021 057 U1 discloses a system for the degradation of gaseous pollutants as a combustion-scrubbing system for reactive gases, wherein the required temperature (for the reaction or removal of these gases) is generated in the combustion chamber. Disadvantages of this system are the high acquisition costs and, due to the energy-intensive handling, the high maintenance costs of such a system. EP 1 070 532 A1 discloses a flow separation system having a mixing chamber with elaborate internal pipes, inlets, and channels. This system is complex and therefore expensive to manufacture, and is suitable only for a relatively limited number of applications. EP 1 129 763 A1 discloses another system that introduces water into the air flow or mixes the air flow with preheated air. This system also has a complex structure, which means that the procedures performed using such a system are also complex and require expensive control. The object of the present invention is therefore to propose a device and a method which avoid the above-mentioned disadvantages, ie which are able to render pollutant gases harmless in an efficient manner. According to the invention, this object is achieved by a device and a method according to the independent claims. Advantageous embodiments and further developments are described in the dependent claims. An apparatus for cleaning or rendering harmless a process gas containing at least one contaminant gas (wherein the process gas itself may also be a contaminant gas) comprises a reactor vessel configured as a centrifugal separator, the reactor vessel having a cylindrical or hollow cylindrical portion and a tapered portion. Oxygen or an oxygen-containing gas can be introduced into the reactor vessel as a reactant gas through at least one gas inlet disposed in the cylindrical portion and can be discharged from the reactor vessel through at least one gas outlet disposed in the tapered portion. The at least one gas inlet is arranged and configured to introduce a defined volumetric flow of reactant gas into the reactor vessel tangentially to the circumferential surface of the cylindrical portion. A contaminant gas inlet is also disposed in the cylindrical portion and is configured to introduce a defined volumetric flow of process gas containing at least one contaminant gas into the reactor vessel, such that the at least one contaminant gas and the reactant gas mix in the direction of the gas outlet and chemically react with each other as they pass through the reactor vessel. The gas outlet is arranged and configured to discharge unreacted process gas from the chemical reaction and reaction products from the chemical reaction from the reactor vessel. This device makes it possible to set up a reactor in a simple manner, and the introduction of various gases determined thereby can achieve reproducible and detectable chemical reactions. The design of the centrifugal separator (also referred to as cyclone, cyclone separator or vortex separator) can not only reliably inhale the gas participating in the chemical reaction and transfer it along the gas outlet direction, but also ensure that due to the setting of the gas inlet, a flow optimization design is achieved, wherein the immediate or complete mixing of gases is generally achieved, rather than just the simple dilution of pollutant gases. In simple terms, compared with prior art, this device or the process carried out therewith and its use are optimized, and can achieve controlled and safe reaction or oxidation, which protects the environment and the surrounding environment and reduces the cost of this program. At the same time, an improved product is achieved, that is, the pollutant gases actually react instead of diluting, thereby achieving a reduction in pollutant gas emissions. Therefore, the reaction product can be selected and reused according to the relative purity of the reaction product. To set a defined volume flow rate, the apparatus can include a volume flow rate setting device, by which a defined volume flow rate of the process gas containing at least one pollutant gas and / or a defined volume flow rate of the reaction gas can be set before introduction into the reactor vessel. Typically, the volume flow rate is between 300 and 2,600 cubic meters per hour, preferably between 600 and 1,300 cubic meters per hour. Alternatively or additionally, the apparatus can include a compressor for introducing the process gas and / or reaction gas into the interior of the reactor vessel. A temperature sensor can be positioned at or within the gas outlet to sense the temperature of the often exothermic chemical reaction in the reactor vessel. The determined temperature can be communicated to the device for setting the volume flow rate so that the defined volume flow rate can be readjusted accordingly, thereby enabling control or, if necessary, regulation of the reaction. Typically, the temperature sensor is located centrally at the gas outlet. Alternatively or additionally, a flow rate sensor may be provided in or at the gas inlet and / or in or at the pollutant gas inlet. The determined flow rate of each gas may also be transmitted to a device for setting a volume flow rate and used as a control parameter or control strategy. For oxidative cleaning, in addition to oxygen, it is also possible in particular to use an ambient air mixture as oxygen-containing reaction gas, which makes the overall process easier. To support the chemical reaction, a heating device can be arranged in or on the reactor vessel. The heating device is preferably designed as a resistance heater and can, if necessary, also be controlled or regulated via a device for setting the volume flow. The reactor vessel itself is typically made of stainless steel, and standardized standard pipes and ISO flanges are typically used for the gas inlet, gas outlet, and pollutant gas outlet, respectively, to keep the design simple and cost-effective. The reactor vessel is typically designed to be gas-tight or fluid-tight near the gas inlet, gas outlet, or pollutant gas outlet. The pollutant gas inlet can be located on the end face, ie the circular surface of the cylindrical section, to ensure direct mixing with the tangentially inflowing reaction gas. The tapering region is generally designed as a conical tapering region. However, in principle, the taper can also be described by a polynomial function and the resulting rotational solid. The gas outlet is typically curved to provide a defined geometry for pure discharge of the gas mixture within the reactor vessel.Preferably, the gas outlet is curved at 90 degrees. The contaminant gas inlet is typically located opposite the gas outlet. Preferably, the contaminant gas inlet is configured such that the contaminant gas is introduced into the reactor vessel rotationally symmetrically with respect to a longitudinal axis of the gas outlet, typically with respect to a central axis of the gas outlet. Removably attached to the gas outlet, ie removable and / or attachable, may be a filter element, a scrubber and / or a collection container for the reaction products, in order to safely collect and remove the reaction products. In a particularly advantageous manner, silanes and / or diboranes can be treated as pollutant gases using the described apparatus. The pollutant gas generally has a residence time in the reactor vessel of between 0.3 seconds and 5.0 seconds, with 0.7 seconds to 2.0 seconds being the preferred residence time. The general treatment temperature range is 20°C to 300°C, preferably 40°C to 200°C. In a process for purifying a process gas containing at least one contaminant gas, oxygen or an oxygen-containing gas is introduced as a reaction gas at a defined volume flow rate into a reactor vessel configured as a centrifugal separator via at least one gas inlet disposed in a cylindrical region, tangentially to the circumferential surface of the cylindrical region. The reactor vessel comprises a cylindrical region and a tapered region. The defined volume flow rate of the process gas containing the contaminant gas is introduced into the reactor vessel via the contaminant gas inlet disposed in the cylindrical region. The contaminant gas and the process gas mix and chemically react with each other while passing through the reactor vessel. During the chemical reaction, unreacted process gas and reaction products are discharged from the reactor vessel via a gas outlet. The described methods can be performed using the described devices, ie the described devices are configured to perform the described methods. FIG1 shows a schematic side view of an example of a device for cleaning process gases containing at least one pollutant gas. Ambient air as a reaction gas can flow into the device via one or more intake or inlet ports 1. From the intake port 1, the reaction gas flows through an angle valve 2, through one or more inlet pipes 3, and through a metering port to an ambient gas mixture port 12 via an elbow. Thus, the intake port 1, the angle valve 2 and the inlet pipe 3 together with the ambient gas mixture connection 12 form a gas inlet into a reactor vessel having a hollow cylindrical region 5 and a conical tapering region 9. Metering ports for various measuring devices can also be provided on the inlet pipe 3. An ambient gas mixture connection 12 is arranged tangentially to the straight, i.e., cylindrical, region 5 of the reactor vessel, which is designed as a cyclone or centrifugal separator. Above the cylindrical region 5, the reactor vessel is sealed gas-tight by a reactor plate 6 or reactor cover, which is provided with a plurality of pollutant gas inlets 8. In the embodiment shown in FIG. 1 , three pollutant gas inlets 8 are visible; in this view, the fourth pollutant gas inlet 8 is obscured by the central pollutant gas inlet. Behind the central pollutant gas inlet 8, an inspection opening with a cover 7 is visible. The pollutant gas inlets 8 are arranged concentrically around the cover 7 on a flow-optimized circle. Consequently, the pollutant gas inlets 8 are rotationally symmetrical with respect to the longitudinal axis or central axis of the transition from the tapered region 9 to the 90-degree bend 10. In a further embodiment, a measuring instrument or scraper, known as a "scraper," can also be introduced into the interior of the reactor vessel through the opening closed by the cover 7 for cleaning purposes, or this opening can be used for inspection purposes. The conical tapered region 9 of the reactor vessel adjoins the cylindrical region 5 at the bottom. Behind this cone of the cyclone is a 90-degree elbow 10, which forms a transition portion to the connection of the exhaust port 11 and thus forms a gas outlet. The ambient gas mixture port 12 is arranged tangentially at a distance from the reactor plate 6. After the short straight pipe, these connections in the illustrated example continue downward with a 90-degree elbow, perpendicular to the base, and terminate at an angle valve 2 with a spring return, the outlet of which extends parallel to the base again. An obliquely cut-off, straight cylinder is provided at this outlet, which serves as an intake or inlet 1 and expands the inflow cross section. This is conducive to the inflow of gas inlet. Through-hole threads can be provided in vertical pipes to accommodate, for example, measuring devices (e.g., Pitot tubes or other volume or velocity sensors). The sizes of these threads are usually selected according to the factory, but they are standardized to tighten airtightly with blind caps. In the embodiment shown in FIG. 1 , the device is arranged in an upright position, i.e. the reactor vessel is oriented with its vertical axis perpendicular to the substrate. The reactor vessel itself has a cylindrical portion 5 at its upper end, which is considered to be further away from the substrate, which merges into a frustoconical tapering region 9 in the direction of the substrate. The device itself ends in an exhaust port 11 in an external frame structure (not shown for the sake of clarity) that supports this device. In the embodiment shown, the pollutant gas inlets 8 are arranged vertically on the reactor plate 6, but in other embodiments, they can also lead to the reactor plate 6 at other angles or also have an arched design. Generally, the pollutant gas inlets 8 are designed as KF flanges so that they can be easily closed for transportation and provide a standardized connection. The device shown in Figure 1 enables cost-effective and robust cleaning or reaction of pollutant gases. Compounds such as silane or diborane are inherently highly reactive but require appropriate support to decompose the compounds from their gaseous state into dust or particles that can then be deposited or ingested downstream. The proposed device and its optimized flow chart (explained in more detail below) enable control and monitoring of this process, ultimately leading to improved purification results compared to previous technologies. The device for oxidizing pollutant gases in the reactor can be isolated from its environment, thereby enabling a flow-optimized inflow of an ambient gas mixture (usually air). Due to the inflow in a cylindrical region 5 tangential to the shell surface and by means of the cyclone principle, a relatively long residence time in the reactor vessel and therefore a thorough reaction are possible without the need for a complex structure. To this end, the reaction gas flows in a vortex of a defined volume from the inner wall of the reactor vessel in the direction of the gas outlet or exhaust 11 by a continuous gas flow. The reaction chamber itself tapers conically in the direction of the exhaust 11. Since the pollutant gas inlet 8 is oriented at the front side so that the vertical axis or longitudinal axis of the entire device is perpendicular to the ground and therefore parallel to the acting gravity, the process gas 22 containing the pollutant gas also flows into the reactor vessel in the direction of gravity, is sucked in by the vortex of the cyclone, and thus flows in the direction of the gas outlet with a spiral movement or helical motion. The process gas 22 containing the pollutant gas is in continuous contact with and reacts with the ambient gas mixture, without losing heat through the reactor walls in the exothermic reaction and without falling below the minimum necessary concentration due to excessive dilution. Ideally, the pollutant gas reacts completely within the reactor vessel until just before the exhaust port 11. This exothermic reaction is ideally controlled by regulating, i.e., adjusting the volumetric flow rate. This can be accomplished by controlling valves at the gas inlet and pollutant gas inlet 8 via a device for regulating the volumetric flow rate (not shown for clarity), such as a computer. For this purpose, a temperature sensor 13 can also be positioned centrally in the exhaust gas stream, continuously measuring the temperature and transmitting it to the device as a control or regulating parameter for setting the volumetric flow rate. Furthermore, in the exemplary embodiment shown in FIG. 1 , it can also be provided that the flow rate or volumetric flow rate in at least one inlet pipe is measured and also transmitted to the device as a control or regulating parameter. Preferably, this measurement is performed using a Pitot tube or a Pitot tube in the direction of flow. In the embodiment shown in FIG. 1 , the inlet for the ambient gas mixture is designed as a standardized pipe, preferably a reactor vessel or reaction vessel, with all connectors made of stainless steel. The inlet can be connected to the piping system via, but is not limited to, a KF flange (small flange) or an ISO flange (International Organization for Standardization). In other embodiments, the apparatus may further include a compressor to selectively allow the inflow of the ambient gas mixture or the process gas. In another embodiment, the reactor plate 6 has at least two ports, one of which is a pollutant gas inlet 8 and the other is used to introduce a heating element with a pollutant gas surface reaction, the reaction temperature of which is higher than the ambient temperature, in particular room temperature of 20° C. This initiates or controls the exothermic reaction at this surface, and if the temperature inside the reactor vessel (i.e., centrifuge or cyclone) is high enough, the heating element can be deactivated and the reaction monitored via a temperature sensor 13 in the exhaust port 11 and / or another temperature detector arranged inside the reactor vessel. The gas outlet is arranged at the point of smallest diameter of the opposite tapered area 9 of the reactor plate 6 (also referred to as the reactor cover). Therefore, in the presence of oxidizing pollutant gases such as silane SiH 4 or diborane B 2H In the corresponding process of FIG6 , the reaction gas first flows into the reactor vessel via the corresponding inlet and forms a cyclonic spiral motion within the reactor vessel, extending from the inlet to the interior of the reactor vessel to the gas outlet. The cyclonic spiral motion is accelerated in the direction of the gas outlet 11 (particularly also through the tapered section 9 ). Ambient air is drawn in as process gas through the gas inlet, for example, by a fan. Preferably, through the entrainment or suction of this spiral motion, the pollutant gas flows in via the pollutant gas inlet 8 , which is positioned, for example, on the inside of the circulating spiral motion. Inside this, the pollutant gas also undergoes the same spiral motion as the reaction gas, resulting in the formation of a contact zone in the reactor vessel, in which the pollutant gas and the reaction gas 21 react as reactants before mixing to a concentration below a minimum, in the case of silane, for example, less than 2% by volume of the gas mixture (in this case, the minimum concentration of the pollutant gas is maintained). The mixed reaction partners initiate a (chain) reaction that results in the complete reaction of the pollutant gas over the distance of the cyclone's spiral motion, so that after the reaction, the two reaction partners become a gas stream consisting of charged reaction gases, preferably in the form of a powder or dust. The gas mixture is accelerated, particularly after entering the cone. This gas stream can be collected, separated, filtered, or scrubbed. For this purpose, a collection container and / or a corresponding filter element or scrubber can be fitted to and / or in the exhaust port 11. For example, the reacted reaction products can be filtered as suspended solids or scrubbed by passing them through a scrubber. Preferably, ultrapure substances are filtered and blown into a collection container for recovery and further processing. If the resulting cyclone motion is stable (this can be achieved, for example, by using a time constant and / or by evaluating measured variables such as pressure difference, volume flow rate, or flow rate), the inflow is achieved by sucking in the process gas through the pollutant gas inlet 8. If necessary, the process gas, together with the pollutant gas (e.g., silane as residual charge from a gas cylinder), can also be limited by a mass flow controller. However, generally speaking, once in the contact zone, the contaminant gas should have a minimum concentration. Depending on the contaminant gas, this minimum concentration corresponds to the critical amount for an independent chain reaction. During the reaction, heat is typically released, which supports the reaction and thus promotes its completion. This is achieved by maintaining a minimum concentration and residence time in the reactor vessel, and by not diluting the reactants, which only mix in the contact zone within the reactor vessel. After the reaction, the two reactants become a gas stream consisting of air and silica, which can be separated if necessary by a filtration unit. The filtration unit can then blow this load into a connected collection vessel, thereby collecting the clean material and allowing the filter unit's filter to be loaded multiple times, releasing the air contaminant-free into the environment. By means of a heating element or heat source, the (chain) reaction can be initiated upon mixing of the reactants and when the reaction has stabilized (this can be the case, for example, by switching off the heating element after a predetermined time or by detecting process parameters such as the temperature of the gas stream and evaluating these process parameters). For this purpose, the heating element can be positioned in the contact zone or in the immediate vicinity of the pollutant gas inlet, i.e., close to the pollutant gas inlet 8 (generally no more than one diameter of the respective pollutant gas inlet 8 from the edge of the pollutant gas inlet 8), or in the pollutant gas inlet 8 itself. In the case of diborane, this additional heating device is generally still used to initiate the reaction, since diborane itself does not react independently with oxygen. Even after the reaction has started, the heating device can be switched off. Although silane and diborane are mentioned as examples, this device and process can of course also be applied to other pollutant gases. FIG2 shows a schematic side view of the apparatus, but now rotated 90 degrees from the view shown in FIG1 and viewed from the rear, without the supporting structure. In this and the following figures, recurring features are designated by the same reference numerals. In particular, the temperature sensor 13, located in the center of the exhaust stream, can now be more clearly seen. Thus, as previously described, the apparatus comprises a cyclone or centrifugal separator having at least two inlets, one for each reactant, which, during its residence time in the reactor, reacts with a less hazardous or reusable substance, thereby becoming non-hazardous to the environment. Furthermore, in the event of an accident, the process can be isolated from the environment by means of safety devices, making it repeatable, controllable, and monitorable. The safety device can include at least one spring-return valve, a safety valve, a limit switch, or a valve that is generally closed when not actuated, or a plurality of these safety devices can generally be used, with different types also being able to be combined. FIG3 shows a schematic diagram of the flow paths (the left portion of the figure corresponds to FIG1 , and the right portion corresponds to FIG2 ). Reaction gas 21 (e.g., an ambient gas mixture) enters the reactor vessel via inlet 1. Influent 23 is directed in inlet pipe 3 to inlet 24 in the reactor vessel, where it forms a cyclonic spiral motion 25, drawing in pollutant gas via pollutant gas inlet 8. The gas flow passes through a 90-degree elbow 10 and enters exhaust 11 as exhaust gas flow 26. As shown in the schematic perspective view of FIG4 , reactant gas 21 enters the reactor vessel tangentially through ambient gas mixture port 12. It then forms a cyclonic spiral 25 within the reactor vessel, flowing downward in a spiral or continuously rotating pattern until it reaches the outlet, 90-degree elbow 10, and exhaust port 11 as exhaust gas stream 26. Cyclonic spiral 25 or cyclonic flow draws in pollutant gas or process gas 22 through pollutant gas inlet 8, forming a contact zone 27 between the two. In FIG4 , the denser lines decrease in the direction of exhaust gas flow, indicating a drop in minimum concentration, i.e., cessation of the reaction. Only the features of the individual embodiments disclosed in the embodiment examples may be combined and claimed individually. 1: Inlet port (gas inlet) 2: Angle valve (gas inlet) 3: Inlet pipe (gas inlet) 5: Cylindrical area 6: Reactor plate 7: Cover 8: Contaminant gas inlet / fourth contaminant gas inlet 9: Tapered area 10: Elbow (gas outlet) 11: Exhaust port / gas outlet 12: Ambient gas mixture port / ambient gas mixture connection (gas inlet) 13: Temperature sensor 21: Reactive gas 22: Process gas 23: Influent 24: Inlet 25: Cyclone spiral motion 26: Exhaust gas flow 27: Contact zone Examples of embodiments of the present invention are shown in the drawings and are explained below with reference to FIG. 1 to FIG. 4 . FIG. 1 is a schematic side view of an apparatus for purifying a process gas containing at least one contaminant gas; FIG. 2 is a view of the apparatus rotated 90 degrees compared to FIG. 1 ; FIG. 3 is a schematic flow path through the apparatus according to FIG. 1 and FIG. 2 ; FIG. 4 is a perspective view of the schematic flow path. none 1: Inlet (gas inlet) 2: Angle valve (gas inlet) 3: Inlet pipe (gas inlet) 5: Cylindrical area 6: Reactor plate 7: Cover 8: Pollutant gas inlet / fourth pollutant gas inlet 9: Tapering area 10: Elbow (gas outlet) 11: Exhaust port / gas outlet

Claims

1. An apparatus for purifying a process gas (22) containing at least one pollutant gas, comprising: A reactor vessel, designed as a centrifuge, has a cylindrical region (5) and a tapering region (9), wherein oxygen or oxygen-containing gas can be introduced as a reactant gas (21) into at least one gas inlet (1, 2, 3, 12) provided on the cylindrical region (5), and discharged through at least one gas outlet (10, 11) provided on the tapering region (9), wherein the at least one gas inlet (1, 2, 3, 12) is provided and formed to introduce a defined volumetric flow rate of the reactant gas (21) tangentially to a circumferential surface of the cylindrical region (5) into the reactor vessel, and a contaminant gas inlet (8) is provided on the cylindrical region (5) and designed to introduce a defined volumetric flow rate of the process gas (22) containing at least one contaminant gas into the reactor vessel, so that: The at least one pollutant gas and the reactant gas (21) mix with each other in the direction of the gas outlets (10, 11), and the at least one pollutant gas and the reactant gas (21) undergo a chemical reaction with each other as they pass through the reactor container. The gas outlets (10, 11) are provided and designed to discharge the unreacted process gas and a reaction product of the chemical reaction from the reactor container. The pollutant gas inlet (8) is located at one end face (6) of the cylindrical region (5) of the reactor container. The port (8) is disposed opposite to the gas outlet (10, 11) and is formed to introduce the contaminant gas (22) into the reactor vessel in a rotationally symmetrical manner relative to a longitudinal axis of the gas outlet (10, 11); and wherein, before the process gas (22) containing at least one contaminant gas and / or the reaction gas (21) are introduced into the reactor vessel, the limited volume flow rate of the process gas (22) containing at least one contaminant gas and / or the limited volume flow rate of the reaction gas (21) can be set by means of a device for setting a volume flow rate.

2. The apparatus for purifying process gas containing at least one contaminant gas as claimed in claim 1, wherein a temperature sensor (13) is disposed on or in the gas outlet (10, 11), and / or a flow rate sensor is disposed in or on the at least one gas inlet (1, 2, 3, 12) or the contaminant gas inlet (8).

3. The apparatus for purifying process gases containing at least one contaminant gas as described in claim 1, wherein a heating device is disposed in or on the reactor vessel to support the chemical reaction.

4. The apparatus for purifying process gases containing at least one contaminant gas as described in claim 1, wherein the tapering region (9) of the reactor vessel is formed as a conical tapering region.

5. The apparatus for purifying process gases containing at least one contaminant gas as described in claim 1, wherein the gas outlet (10, 11) is curved in an arc shape.

6. The apparatus for purifying process gases containing at least one contaminant gas as described in claim 1, wherein the gas outlet (10, 11) is bent at 90 degrees.

7. The apparatus for purifying a process gas containing at least one contaminant gas as described in claim 1, wherein a filter element, a scrubber, and / or a collection container for the reaction products are removably attached to the gas outlet (10, 11).

8. A method for purifying a process gas containing at least one pollutant gas, wherein: A predetermined volumetric flow rate of oxygen or oxygen-containing gas is introduced as a reactant gas (21) into a reactor vessel tangentially to a circumferential surface of a cylindrical region (5) via at least one gas inlet (1, 2, 3, 12) disposed on the cylindrical region (5). The reactor vessel is designed as a centrifuge and has the cylindrical region (5) and a tapering region (9). A predetermined volumetric flow rate of process gas (22) containing contaminant gas is introduced into the reactor vessel via a contaminant gas inlet (8) disposed on the cylindrical region (5). The contaminant gas (22) and the reactant gas (21) mix and react chemically during passage through the reactor vessel. Unreacted process gas and reaction products are also reacted during the chemical reaction. The contaminant is discharged from the reactor vessel through a gas outlet (10, 11), wherein the contaminant gas inlet (8) is located at one end face (6) of the cylindrical region (5) of the reactor vessel; wherein the contaminant gas inlet (8) is disposed opposite to the gas outlet (10, 11) and is formed to introduce the contaminant gas (22) into the reactor vessel in a rotationally symmetrical manner relative to a longitudinal axis of the gas outlet (10, 11); and wherein before the process gas (22) containing at least one contaminant gas and / or the reaction gas (21) are introduced into the reactor vessel, the limited volume flow rate of the process gas (22) containing at least one contaminant gas and / or the limited volume flow rate of the reaction gas (21) can be set by a device for setting a volume flow rate.

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