DE102006011822A1 - Reactor for heterogeneous gas phase reactions, apparatus for testing catalysts for heterogeneous gas phase reactions and methods for testing such catalysts - Google Patents

Abstract

The present invention relates to a reactor for carrying out heterogeneous gas phase reactions or for testing catalysts for heterogeneous gas phase reactions, comprising - at least one reactor vessel with an inlet end and an outlet end, containing at least one receiving device for a catalyst, at least one inlet opening for gas to be converted in the area of the inlet end and at least one outlet opening for converted gas in the area of the outlet end, - at least two units for cooling the reactor vessel, which are in thermal contact with the reactor vessel at least in the section in which the receptacle for the catalyst is located, and - at least one, in particular at least two, units for heating the reactor vessel, each in thermal contact with the reactor vessel in at least one section in which the receptacle for the catalyst is present in the reactor vessel ter stand, wherein the cooling and heating units are arranged in such a way that the reactor vessel can be heated or cooled at least in the region of the receiving device for the catalyst, in particular substantially homogeneously. The invention further relates to a device for testing catalysts for heterogeneous gas phase reactions, comprising at least one reactor according to the invention, at least one gas supply line to the reactor, at least one ...

Description

The The present invention relates to a reactor for carrying out heterogeneous Gas phase reactions and for testing catalysts for heterogeneous Gas phase reactions and a method and apparatus for testing of catalysts for heterogeneous gas-phase reactions.

Although known for a long time, heterogeneous gas phase reactions are still becoming more important, not least because of the very cost-effective use of the catalyst material. Its reusability is just as important here as the generally unproblematic handling of reactants and products. For heterogeneous gas phase reactions, both reduction catalysts, for example in the selective reduction of hydroxyl groups or the partial hydrogenation of double bonds, as well as oxidation catalysts, such as, for example, in motor vehicles as catalytic converters into consideration. With the help of such catalytic converters, for example, sulfur-containing residues, carbon monoxide, polycyclic aromatic compounds, nitrogen oxides and soot particles should be removed. For example, in SCR (Selective Catalytic Reduction) technology, nitrogen oxides on a suitable catalyst are reduced to nitrogen in the presence of ammonia. SCR catalysts are generally based on one element from the group Pt, Pd, Rh, Ir, Au, Ag and Ru. For the continuous regeneration of particle filters is based on the so-called CRT method (continuous regeneration trap), as in DE 199 55 124 A1 and the DE 103 21 105 A1 described, resorted to. The particulate filter is preceded by an oxidation catalyst in the exhaust pipe, which oxidizes the nitrogen oxide contained in the exhaust gas to nitrogen dioxide, which is then used for the oxidation of carbon monoxide or carbon black.

Around to one for the mass production suitable exhaust catalyst to arrive, are usually numerous test series and optimization cycles are required. The effort for Such tests are further increased by the fact that the catalysts to be tested generally applied to a suitable monolith and for each individual Catalyst composition to find out the optimum reaction temperature are. A characteristic parameter for catalytic converters is the so-called light-off temperature. This is the one Catalyst temperature at which this 50% of its nominal conversion rate reached.

The DE 102 54 477 B3 proposes a test method for the determination of the functionality of an exhaust gas catalytic converter, which makes it possible to ren waive a separate temperature sensor th, without in this case the fuel consumption is significantly increased. The test device used for this purpose is still very expensive and requires, for example, an injection system for test injection of a predetermined amount of fuel during an expansion stroke or during an exhaust stroke of the internal combustion engine, an exhaust gas recirculation device, a measuring direction and an evaluation unit.

Also, the method according to the DE 103 33 337 A1 makes use of the determination of the light-off temperature to measure a catalyst system with a near-engine pre-catalyst and a main catalyst. Here, specific attention is paid to the oxygen storage capacity of the primary and the main catalytic converter.

The DE 101 01 118 A1 discloses a very complex method for evaluating the performance of solid catalysts. Thereafter, a high-throughput screening can be achieved by rapid determination of kinetic data in a large number of parallel-operated reactors. The concentrations of the key reactants and products are measured at the reactor inlet and outlet of each individual reactor charged with different catalytic materials. In addition, the concentration determinations of the reactants at the reactor outlet are made for different temperatures, residence times, pressures and reactant concentrations at the reactor inlet. In this way, the catalyst performance should be predictable under different reaction conditions. That in the DE 101 01 118 A1 described method is very complex in terms of apparatus and process technology.

The US patent application US 2003/0012790 A1 relates to a method for parallel testing of catalyst systems, paying special attention to the arrangement and design of feed valves for the reaction gas is placed. With the device according to US 2003/0012790 A1, a Variety of different reactors with one and the same uniform Reaction gas to be charged in parallel.

Also WO 2005/047887 A1 discloses a method and a device for testing a variety of catalyst samples. Here are on predetermined Manner load reactor vessels serially from a storage zone transferred to a reaction zone in which the reaction vessel with a is heated at a predetermined rate.

From the US 4,099,923 discloses an apparatus for automatically screening a variety of catalyst systems. This device requires a large number of reactor units, heating modules, gas feeders and analysis and control units.

It would be desirable rely on devices for testing a variety of catalysts to be able to which are not subject to the disadvantages of the prior art. The present invention therefore an object of the invention Apparatus with simple apparatus for testing catalysts available make short repetition cycles possible, which allows a direct and timely analysis of the reaction products and with the characteristic parameters such as the light-off temperature even with high sample throughput can be determined with high accuracy. Furthermore, the invention was the object of reactors for such Devices available too put.

• – mindestens einen Reaktorbehälter mit einem Einlaßende und einem Auslaßende, enthaltend mindestens eine Aufnahmevorrichtung für einen Katalysator, mindestens eine Eintrittsöffnung für umzusetzendes Gas im Bereich des Einlaßendes und mindestens eine Austrittsöffnung für umgesetztes Gas im Bereich des Auslaßendes,
• – mindestens zwei Einheiten zum Kühlen des Reaktorbehälters, die mindestens in dem Abschnitt, in dem in dem Reaktorbehälter die Aufnahmevorrichtung für den Katalysator vorliegt, jeweils in thermischem Kontakt mit dem Reaktorbehälter stehen, und
• – mindestens eine, insbesondere mindestens zwei Einheiten zum Heizen des Reaktorbehälters, die mindestens in dem Abschnitt, in dem in dem Reaktorbehälter die Aufnahmevorrichtung für den Katalysator vorliegt, jeweils in thermischem Kontakt mit dem Reaktorbehälter stehen, wobei die Kühl- und Heizeinheiten in der Weise angeordnet sind, daß der Reaktorbehälter wenigstens im Bereich der Aufnahmevorrichtung für den Katalysator, insbesondere im wesentlichen homogen, erwärmbar bzw. abkühlbar ist.

The problem underlying the invention is solved by a reactor for carrying out heterogeneous gas phase reactions or for testing catalysts for heterogeneous gas phase reactions

• At least one reactor vessel having an inlet end and an outlet end containing at least one receiving device for a catalyst, at least one inlet opening for gas to be converted in the region of the inlet end and at least one outlet opening for reacted gas in the region of the outlet end,
• - At least two units for cooling the reactor vessel, which are in thermal contact with the reactor vessel at least in the section in which there is in the reactor vessel, the receiving means for the catalyst, in thermal contact
• - At least one, in particular at least two units for heating the reactor vessel, which are in thermal contact with the reactor vessel at least in the portion in which there is in the reactor vessel, the receiving device for the catalyst, wherein the cooling and heating units arranged in the manner are that the reactor vessel at least in the region of the receiving device for the catalyst, in particular substantially homogeneous, can be heated or cooled.

Of the reactor vessel can represent a pipe, for example, but can also be any suitable container shape accept that for the implementation a heterogeneous catalytic gas phase reaction is suitable. About the inlet end can the reactor vessel be charged with the catalyst material. Depending on the amount of at the gas phase reaction pressure applied, the inlet end, if appropriate be sealed. Under the outlet end of the reactor should in the sense the present invention is understood to mean that region to the reaction zone, ie to the area in which the catalyst is present, connects and in which the product gases are transported after the reaction. Preferably closes the opening of the reactor immediately to the outlet end. In this case forms the opening of the outlet end the exit opening. Likewise, in one embodiment the opening of the inlet end with the entrance opening coincide. The (gas) inlet can also be at a different location of the reactor vessel or inlet end be provided. about the inlet end is regularly the Catalyst supplied and taken again. The receiving device for the catalyst is thus preferably between the intake and the outlet end of the reactor.

homogeneously heatable or coolable in the context of the present invention, a uniform heating or cooling down of the reactor or of the reactor vessel at least in the area of the recording device include, without striking Temperature steps or jumps exhibit.

In A further embodiment provides that the receiving device for the catalyst one for Gas permeable Underlay or one for Gas permeable container represents.

Especially preferably, the receiving device provides as a gas-permeable pad a sieve, preferably made of stainless steel, or a porous mat. Hereby can especially Kata lysatorpulver well registered and recorded. For monoliths can be selected as a holding device, a holding element. This may, for example, consist in the taper of the interior of the reactor vessel, so that one further slippage of the monolith is prevented. To the equipment expense and the equipment costs as possible low, the reactor vessel can also be designed in such a way that that in it find only miniaturized monoliths. Alternatively to a Catalyst in powder form can also be applied to catalyst granules or pellets resorted become. The advantage with the reactor according to the invention or that described below device according to the invention also To be able to use catalyst powder, is next to the possible Miniaturization to behold that on the elaborate production from monoliths can be dispensed to test experiments. For monoliths has become common proved problematic that the Catalyst job is uneven. Herewith For example, when determining the light-off temperature error limits in the range of +/- 10 ° C, whereas with the reactors according to the invention and devices error limits in the range +/- 2 ° C and less accessible.

Preferably, the cooling and / or heating units are in thermal contact between the inlet end and the outlet end of the reactor vessel with this before.

advantageously, comprises the cooling unit at least a cavity or a bore with an inlet end and an outlet end to Passage of cooling gas, in particular compressed gas. As a rule, it is already sufficient, in particular against the background of a desired Miniaturization of the reactor to choose diameter for the cavities or holes, the in the range of 3 to 15, preferably from 4 to 10 mm. The Cavities or Drilling can be configured such that a cooling liquid as the cooling medium insertable or is passable.

The cooling unit in the sense of the present invention is accordingly designed in the manner that she the cooling of the reactor vessel or reactor allows. A cooling module, i.e. a device with which the cooling of the reactor or reactor vessel ultimately Be accomplished, for example, such a cooling unit include, in the cavity of a cooling rod, for example containing liquid nitrogen is present. The cooling is preferred brought by one with the cavity or the bore of the cooling unit connected or connectable compressed gas line. This system of compressed gas line and cooling unit then also provides a cooling module in the sense described above.

Of Another can be inventively provided be that the Heating unit at least one cavity or a bore for receiving comprises at least one heating element. This cavity may optionally also throughout be. As a rule, it is already sufficient, especially against the background a desired one Miniaturization of the reactor to choose diameter for the cavities or holes, the in the range of 3 to 15, preferably from 4 to 10 mm.

suitable Heating elements include, for example, electrical heating resistors, for example in the form of heating cartridges. Cartridge heaters are advantageously such designed that she essentially in registration into the cavity of the heating unit are inserted to an optimum Heat transfer to ensure. With these heating elements can be temperatures of, for example Achieve 1400 ° C, wherein Of course even higher Temperatures possible are.

One particularly good heating or cooling of the reactor is achieved by that the Heating and cooling units arranged alternately around the reactor vessel are. Preferably, the heating and cooling units are concentric around the reactor vessel in front.

When It has also proved advantageous, in each case, that adjacent heating and cooling units predominantly not in contact with each other. That way you can once again increased cooling and achieve heating rates without thereby the homogeneity of the heating or Cooling impaired becomes.

in the general is for this already sufficient that each adjacent heating and cooling units through material recesses that at least partially between the inlet and the outlet of the reactor vessel extend, are separated.

According to one In a particularly preferred aspect of the present invention, the reactor further comprises a sheath which is at least partially spaced from the cooling and heating units and the reactor vessel at least partially, especially in its entirety, surrounds. This allows the intended cooling and heating effects accelerate again. A particularly effective development hereby includes at least one baffle for diverting the through the outlet end of the cavity of the cooling unit exiting refrigerant gas through the space between the sheathing and the cooling and heating units. Becomes For example, compressed gas passed through the cooling unit, this is through the baffle then deflected in the opposite direction between the outer wall the reactor or the heating and / or cooling units and the jacketing to escape. The compressed gas is thus used twice for cooling. jacket and baffle are preferably connected to each other, in particular sealed, or connectable and in one embodiment one piece executed.

A further preferred embodiment further comprises at least one supply line for the gas to be reacted to the reactor vessel, the at least partially is present in thermal contact with at least one heating unit. Instead of the supply line of the gas to be reacted supplying a spaced conduit to the inlet of the reactor in this embodiment this Conduction brought into thermal contact with a heating unit to so preheat the gas, resulting in even faster heating rates and thus shorter ones measuring cycles let accomplish.

It is advantageous with regard to the precise monitoring of the investigated activity of the catalysts if the reactor further contains at least one first temperature sensor, in particular a first thermocouple, within the reactor vessel. A particularly accurate tracking of the temperature behavior succeeds in particular when the temperature sensor is present in the region of the receiving device of the catalyst, so that the temperature is measurable in a catalyst sample. The accuracy in the tracking of the reactions investigated is increased again by a second, in the wall of the reactor vessel adjacent to the receiving device of the catalyst temperature sensor. The sensor is preferably present in the wall, which is in contact with the catalyst sample or the receiving device. In this way, even more reliable temperature control of an individual reactor can be controlled or regulated. Also, the heat of reaction of a reactive gas mixture can be very accurately recorded in an exothermic heterogeneous catalytic gas phase reaction. Such heat of reaction can be detected, for example, for a catalytic oxidation of a carbon monoxide / propane gas mixture at a reactor temperature of about 300 ° C, even if the heat of reaction only have a minimal effect.

According to one another embodiment of the reactor according to the invention are the reactor vessel, the cooling unit (s) and / or the heating unit (s) made in one piece. Accordingly, e.g. Cooling and heating units, cooling units and reactor vessels, Heating units and reactor vessels or Cooling units Heating units and reactor vessels one piece executed. The use of one piece Module provides in particular in the handling of the reactors before especially if a large number of reactors are used side by side considerable advantages.

From particular advantage in this context is such a reactor, comprising at least one tempering, the at least two units for cooling of the reactor vessel and at least one, in particular at least two units for Heating the reactor vessel contains wherein the tempering at least in the section in which in the reactor vessel the receiving device for the catalyst is in thermal contact with this reactor vessel or can be brought and wherein the cooling and heating units can be arranged in such a way that the reactor vessel in the Area of the receiving device for the catalyst, in particular essentially homogeneous, heatable or coolable is.

The Temperieraggregat thus includes modular cooling and Heating units of the reactor. Again, it is an advantage if the temperature control unit is essentially in one piece. With regard to the preferred embodiments the heating and cooling units Temperieraggregats the foregoing applies here accordingly.

Especially preferably Temperieraggregat and reactor vessel are in the essential in one piece trained before.

The Recording device for For example, the catalyst can be readily used for catalyst amounts be designed in the range of 20 mg to 700 mg. To be favoured with the reactor according to the invention powdery Catalysts used. Their amount and / or activity can be for example, by adding suitable inert bulk materials how they control silicon carbide.

In an alternative embodiment the heating unit may have a heating resistor, for example in the Form of a heating wire comprise, which at least the reactor vessel in the field of receiving device for the catalyst and / or the cooling unit (s) surrounds at least in the region of the receiving device for the catalyst. at this form of design can be the number of cooling units, those around the reactor vessel can be arranged around, increase again, resulting in shorter measuring cycles possible become.

Prefers can in such an embodiment, e.g. 4, 5 or 6 cooling units are adjacent to each other and surround the reactor vessel.

Lie for example, two or more cooling and / or Heating units, these are preferably mounted alternately around the reactor vessel. For preferred Reactors usually already have three cooling units and three heating units, which are mounted alternately out. Satisfactory results become self-evident even with a small number of cooling and / or heating units achieved. Of course can also be a larger number at cooling or heating units, for example 4, 5, 6 or 7 such units, around the reactor vessel, preferably alternating, be attached. By a uniform, in particular alternating, arrangement of cooling and heating units around the reactor vessel, it is ensured that the reactor vessel at least in the area of the receiving device for the catalyst substantially homogeneously heated or cooled is.

The The object underlying the invention is further achieved by a device comprising at least one reactor according to the invention, at least one gas supply line to the reactor, at least one product gas discharge line from the reactor, at least one analysis unit operatively connected to the product gas discharge line and an evaluation unit in operative connection with the analysis unit. in principle is the device according to the invention by a multiplicity of reactors according to the invention, for example 2, 3, 4, 5, 6, 7, 8 or more equippable.

The reactors of the invention are characterized in particular by the fact that with them to realize very fast heating and cooling rates. Common heating rates (temperature ramps) are, for example, in the range from 150 to 200 K / min, in particular from 170 to 200 K / min. Consequently, reaction temperatures within the reactor vessel of about 500 ° C can be achieved in a very short time. Depending on the heating units and heating elements used, of course reactor temperatures in the range of 1000 to 1500 ° C are readily possible. If the reactor according to the invention is heated to very high temperatures, it is advisable not to use air as the compressed gas for the cooling, but an inert compressed gas in order to prevent scaling of the reactor block.

in this respect with the reactors according to the invention very fast heating and cooling rates allows be reached, one arrives at very short measuring cycles. This can be even with a small number of reactors a continuous continuous operation upright of the device according to the invention receive. For example, four or five reactors according to the invention already suffice out, to, without additional cooling phases after having to insert Go through the test of the located in the fourth and fifth reactor Catalyst immediately afterwards in the first Reactor present catalyst to another test to be able to. Of course let yourself with the device according to the invention also a single reactor or any reactor after completion of the Tests by a new reactor containing for example one modified Amount of catalyst and / or type of catalyst.

suitable Analysis units include, for example, mass spectrometers, IR spectrometers, gas chromatographs and flame absorption spectrometers.

The inventive device comprises in a preferred embodiment Furthermore, at least one evaporator unit for feeding steam and / or gaseous organic compounds in the gas supply line. By using an evaporator unit can Substances such as water vapor and volatile hydrocarbons in the (educt) gas stream are introduced, whereby highly realistic catalytic exhaust gas compositions, as they usually do can be released from internal combustion engines, simulated.

The inventive device comprises according to a preferred further development, a multiple valve; at least a first gas supply line to the multiple valve, at least a second gas supply line from the multiple valve to at least one first reactor, at least a gas discharge line from the first and / or second reactor to the multiple valve and at least one gas discharge line from the multiple valve to the analysis unit. Preferably comprises a such device further comprises at least one second gas supply line from the multiple valve to a second reactor. Suitable multiple valves are e.g. 6-, 8-, 10- or 12-way valves.

In an alternative embodiment, this device also contains at least one bypass sample loop connected to the multiple valve is in active connection. The use of bypass sample loops let yourself for calibration for measurements to be performed use. For example, the educt gas or a component of the Starting gas at different concentrations through the bypass sample loop are passed before it is fed to the analysis unit.

Especially for the Testing of catalytic converters has occurred when using water or water vapor-containing educt gases such a device proved to be suitable, further comprising a heatable container, in the multiple valve, if necessary the bypass sample loop (s), in each case at least in sections the gas supply line to the reactor (s), in each case at least in sections the gas supply line (s) to the multiple valve, in each case at least in sections the gas removal line (s) from the reactor to the analysis unit, the gas discharge line (s) to the multiple valve, optionally the outlet end of the reactor or of the reactors, and / or in each case at least in sections the gas discharge line (s) of the multiple valve is present to the analysis unit, includes. In one embodiment lie in the heated or heated container, the multiple valve, at least sections of the gas supply lines to the reactors, the gas supply lines to the multiple valve, the gas discharge pipes from the reactors to the multiple valve and the gas discharge lines from the multiple valve to the analysis unit. By taking all relevant components of the device according to the invention, which are not already conditionally heated by the measurement or may be a condensation of water droplets or of e.g. aliphatic or aromatic hydrocarbons prevented become. In general, it is already sufficient for this, the heatable container to heat to temperatures in the range of about 65 to 90 ° C.

According to a further aspect, devices according to the invention are provided, in which the discharge line of a first reactor is connected or connectable to the inlet opening of a second reactor. It can further be provided that the Gasabführleitung the second reactor connected to the inlet opening of a third reactor or is connectable.

Especially if applicable, optimum conditions for series-connected catalysts to find how they are used in catalytic converters for internal combustion engines are passed, one passes that in a reactor of the device according to the invention product gas obtained in the second reactor. This type of product gas guidance can as often as you like to the x'th Reactor are repeated, whereupon the final product gas obtained the analysis unit, directly or via the multiple valve supplied becomes. To get an even closer look at the behavior of the individual Obtained in series catalysts can be obtained from the gas discharge line the first reactor and / or the gas discharge line of the second reactor or any other series-connected reactor product gas, direct or over the multi-valve, feed the analysis unit.

Especially for the induction a direct and timely analysis of the product gas obtained It has proved to be very advantageous, the device of the invention with a unit for dilution the product gas with a diluent gas upstream equipped by the analysis unit. Suitable diluent gases represent inert gases such as argon or nitrogen.

• a) Durchleiten eines umzusetzenden Gases durch einen ersten Reaktor bei einer ersten Temperatur, in dem in bzw. auf einer Aufnahmevorrichtung ein erster Katalysator für eine heterogene Gasphasenreaktion vorliegt,
• b) Bestimmen der Temperatur des Katalysators,
• c) Zuführen des diesen Reaktor verlassenden, umgesetzten Gases, insbesondere über ein Mehrwegeventil zu einer Analyseeinheit,
• d) quantitative und/oder qualitative Bestimmung einzelner oder sämtlicher Komponenten des umgesetzten Gases,
• e) Zuordnen der qualitativen und/oder quantitativen Analyseergebnisse zu der detektierten Katalysatortemperatur in einer Auswerteeinheit und
• f) Wiederholen der Schritte a) und e) bei unterschiedlichen Temperaturen und/oder mit einem zweiten oder weiteren Reaktor und/oder einem zweiten und/oder weiteren Katalysator.

The object underlying the invention is further achieved by a method for determining the activity of catalysts for heterogeneous gas phase reactions using a device according to the invention, comprising the steps:

• a) passing a gas to be reacted through a first reactor at a first temperature, in which a first catalyst for a heterogeneous gas phase reaction is present in or on a receiving device,
• b) determining the temperature of the catalyst,
• c) supplying the reacted gas leaving this reactor, in particular via a multi-way valve to an analysis unit,
• d) quantitative and / or qualitative determination of individual or all components of the reacted gas,
• e) assigning the qualitative and / or quantitative analysis results to the detected catalyst temperature in an evaluation unit and
• f) repeating steps a) and e) at different temperatures and / or with a second or further reactor and / or a second and / or further catalyst.

With the device according to the invention or the method according to the invention can be catalysts for test heterogeneous gas-phase reactions very quickly and reliably, which regularly a very efficient optimization of the investigated gas phase reaction succeeds. This applies in particular to the testing of catalytic converters. In addition, all other come Oxidation and reduction catalysts in question. Exemplarily be on Catalysts directed to carbon monoxide oxidation, as in gas masks be used. Further examples are the hydrogenation of acrolein in the gas phase as well as the high-temperature oxidation of methane. The Optimization of the catalytic combustion of methane supplies particularly impressive example of the effectiveness of the reactors of the invention or device, but can be uncomplicated, (cost) efficient Be tried to find suitable catalyst systems, the already at temperatures in the range of about 1300 ° C a catalytic Initiate combustion. Usually requires the combustion of methane temperatures of about 1600 ° C. At these temperatures however, it becomes common a scaling of the reactor vessel material observed.

For example can be with the inventive device implementation of Carbon monoxide, hydrocarbons, for example propane, nitrogen oxides, Hydrogen, sulfur oxides and ammonia follow easily. The determination of the respective light-off temperatures succeeds with high accuracy.

Of the present invention was the surprising Understanding that with the reactor according to the invention can achieve very fast heating and cooling rates, which again very short repetition cycles become possible. Furthermore was surprising found that with the device according to the invention for testing catalysts already with little equipment, for example, with a small number of reactors, a very spacious and reliable Mass screening possible is. Furthermore, the device according to the invention is suitable for analyze the resulting reaction products directly and promptly to be able to. After all can be very accurate even when using powdered catalyst samples useful conclusions on Pull catalysts grown on monoliths.

Further Features and advantages of the invention will become apparent from the following Description, in the preferred embodiments of the invention by way of example are explained with reference to schematic drawings. Showing:

1 a schematic longitudinal sectional view through a reactor according to the invention;

2 a schematic cross-sectional view through the reactor according to the invention according to 1 ;

3 a schematic cross-sectional view through an alternative embodiment of a reactor according to the invention;

4 a schematic longitudinal sectional view through an alternative embodiment of a reactor according to the invention;

5 a schematic longitudinal sectional view through a further alternative embodiment of a reactor according to the invention;

6 a schematic representation of the device according to the invention;

7 a schematic representation of the interconnection of reactors according to the invention in an embodiment of the device according to the invention;

8th a schematic representation of an alternative embodiment of the interconnection of reactors according to the invention in an embodiment of the device according to the invention;

9 a schematic representation of another alternative embodiment of an interconnection of reactors according to the invention, at least one gas discharge line from the first and / or second reactor to the multiple valve;

10 a schematic longitudinal sectional view of a dilution device for the product gas;

11 a temperature profile for a measurement program for a reactor according to the invention of a device according to the invention;

12 a temperature profile during a measuring cycle with a device according to the invention;

13 a diagram obtained by the method according to the invention, for determining the CO light-off temperature; and

14 a diagram of determined by the device according to the invention CO light-off temperatures.

1 is a schematic longitudinal section through a reactor according to the invention 1 refer to. This reactor has an inlet end 2 with an entrance opening 4 and an outlet end 6 with an outlet opening 8th , In the outlet end 6 facing half of the reactor vessel 10 is a cradle 12 in the form of a stainless steel net placed on a catalyst sample 14 is present. In the bed of powdered catalyst sample 14 is a thermocouple 16 introduced in order to detect the reaction temperature of the catalyst continuously or punctually.

Based on the cross-sectional view of 2 of in 1 pictured reactor 1 is the alternate arrangement of cooling units 18 and heating units 20 to be seen concentrically around the reactor vessel 10 are arranged. The cooling and heating units 18 . 20 lie at the in 2 illustrated embodiment as a one-piece tempering 22 before that the wall of the tube-like reactor vessel 10 surrounds in an exact fit. Suitable reactors according to the invention can advantageously be highly miniaturized without having to accept sacrifices in the validity of the results obtained. The length of a reactor vessel may be, for example, in the range of 5 to 25 cm. The diameter of such a reactor can, for example, be in the range of 3 to 15 mm, preferably 4 to 10 mm.

A preferred embodiment of a reactor according to the invention 1 has one in the 3 reproduced cross-section. The cooling units 18 and heating units 20 are each through recesses 24 separated from each other and therefore have only adjacent to the wall of the reactor vessel 10 about mutual contact. As a result, the weight or the total mass of the reactor to be heated is further reduced, which again involves shortened heating and cooling phases. In the cavities 28 the heating units 20 For example, heating cartridges to form a heating module 30 insertable. By dimensioning the heating cartridges as small as possible, the heating unit can 20 be downsized. Even with this measure, the heating and cooling behavior of the reactor can be further improved.

The cooling when using cooling gas can by pre-cooling the compressed air or the compressed gas, for. B. by means of cryostat, and / or by increase of the gas or air pressure can be increased again. For example, can be the reactor according to the invention to cool easily from 500 ° C to room temperature in 20 minutes.

The cooling units 18 are preferably with a continuous cavity 26 provided to pass compressed air or compressed gas for cooling. As well as for the heating unit 20 is for the cooling unit 18 preferably a good thermally conductive material is used, which surrounds the respective cavities and in contact with the reactor vessel 10 stands.

Of the 4 is a preferred embodiment of a reactor according to the invention 1 refer to. This can be the reactor vessel 10 surrounding cooling and heating units 18 and 20 in turn, but spaced, from a shell 32 be surrounded. This sheath 32 is preferably with a baffle 34 adjacent to the end of the cooling unit 18 or cooling units attached, from which the pressure gas used for cooling or the compressed air emerges. In particular, when the baffle is sealed to the reactor vessel 10 or the outlet end 6 connected, succeeds a particularly effective diverting the cooling gas, which on the outer walls of cooling and heating units 18 . 20 is passed and this additionally cools. The pressurized gas or compressed air then escapes advantageously over a region opposite the outlet end.

The compressed air guide described again goes particularly clearly from the schematic Längsschntittsansicht a reactor according to the invention according to 5 out. The compressed air is through the continuous cavity 26 the cooling unit 18 passed and at the baffle 34 in the region of the outlet end of the reactor 1 diverted. This preferred embodiment of a reactor according to the invention also has a supply line 36 for the gas to be converted to the inlet opening 38 in the area of the inlet end 2 , This supply line 36 is along a heating unit 20 conducted in thermal contact with this. In this way, the gas to be reacted can be preheated in the reactor vessel 10 be introduced.

6 shows a schematic system diagram of a device according to the invention 40 , The device 40 comprises five reactors according to the invention 1 (R1, R2, R3, R4 and R5), as described above, which are all coolable with compressed air. About a suitable, in particular variable, gas supply 42 , For example by means of MFCs, the reacted gas or gas mixture is provided. This gas to be reacted can by means of a Gaszuführleitung 46 either directly or, as shown, via a multiple valve 44 the respective reactors 1 be supplied. From the multiple valve 44 , eg a 12-way valve, each gas supply lines go 64 to the inlet openings of the respective reactors 1 out. Accordingly lead gas discharge lines 48 from the outlet openings 8th the reactors 1 back to the multiple valve 44 , About another discharge line 50 the reacted gas or gas mixture passes from the multiple valve 44 to the analysis unit 52 ,

Furthermore, an evaporator unit 54 be provided on the example of water vapor or gaseous hydrocarbons in the gas supply 42 originating gas be fed before this the reactors 1 is supplied. The evaporator 54 can be supplied with water, for example, with an LFC. To prevent any condensation of liquid, such as water, you can see, as in 6 shown a heated container 56 before, in which the multiple valve 44 as well as the supply lines 46 and 64 and the discharge lines 48 and 50 , in each case at least in sections, as well as the Bypaßschlaufen present.

In the in 6 reproduced device according to the invention 40 are all 5 reactors 1 over the multiple valve 44 sequentially controllable. Of course it is also possible, as in 7 reproduced, the discharge line 58 of the first reactor 1 (R1) in the inlet opening 4 another reactor 1 (R3) to enter. Only after the product gas of the reactor R1 has also been exposed to a heterogeneous catalytic reaction in the reactor R3, this is via the discharge line 48 either via the multiple valve or directly, the analyzer 52 fed. Alternatively, at least part of the product gas originating from the reactor R1 may be present in the analysis unit 52 be supplied. Based on the (intermediate) results thus obtained, it is possible to intervene in the temperature control of the downstream reactor R3 via a system control or control unit belonging in one embodiment to the device according to the invention. The analysis results obtained can thus have a direct influence on the heating control or temperature ramps of individual or all reactors. In this way, catalytic converters can be simulated and optimized without any problems. For example, in a first reactor, there may be a catalyst that oxidizes NO to NO ₂ . The resulting NO ₂ is then used to oxidize hydrocarbons to carbon dioxide with the aid of a second catalyst. At the same time, the NO _{2 is} reduced to NO. Finally, the reactive NO is oxidized to NO ₂ using a third catalyst.

Like that 8th and 9 can be seen, opens the device of the invention manifold combination options to the reactors of the invention 1 to connect with each other in series or in parallel.

In 10 is a dilution device 62 reproduced, with which the product gas withdrawn from a reactor is diluted before being fed to the analysis unit. As a diluent gas, for example, nitrogen comes into question. By using a dilution device in the device according to the invention 40 provides, the product gas without loss of time the analysis unit, such as a FT-IR device, are supplied. For example, as miniaturization of the device according to the invention progresses, a volume flow required for the analysis unit can only be achieved by dilution. In addition, by way of Ver Thinning of the product gas, a condensation of liquids, such as water, or the reaction of nitrogen oxides are pushed back. Thus, the volume flow can be diluted with the dilution device according to the invention readily 10 times.

11 shows a temperature / concentration profile for two reactors according to the invention 1 a device according to the invention 40 , In addition to the two reactors 1 is the presently used embodiment of a device according to the invention with a bypass loop 60 equipped with the aid of a control unit, containing suitable control software, different concentrations of educt gas for calibration were set. Preferably, towards the end of the bypass phase, the composition of the reaction gas to be tested is set. After switching the multiple valve from the bypass loop to the first reactor has been waiting for a short time to heat the Reak sector to achieve a uniform distribution of the reaction gas in the container. The temperature ramp was then started starting from an initial temperature of 70 ° C (first temperature) in the reactor vessel in the range of 150 K / min. Again 11 it can be seen, the reaction gas carbon monoxide has been completely implemented via the present in the reactor vessel oxidation catalyst. Subsequently, a bypass sample loop can again be approached via the multiple valve in order to carry out a renewed calibration in preparation for the measurement cycle in the second reactor. During these phases, the temperature of the first reactor is cooled down within a few minutes by means of cooling gas as described above.

12 shows a temperature / time diagram for a device according to the invention, comprising a total of four reactors according to the invention. These reactors are started up sequentially, ie heated with a very high heating rate and then cooled again using compressed air. This cooling process is so fast for all reactors that, as well as the measurement cycle for the fourth reactor is completed in sequential operation, the first reactor has reached its initial temperature again and for a new measurement cycle, ie a new heating phase is available.

13 shows a recorded by means of an analysis unit of a device according to the invention result of the reaction of carbon monoxide over time with increasing the temperature in a reactor according to the invention. On the basis of determined at different times carbon monoxide concentrations can easily determine the light-off temperature.

14 finally, shows the result of light-off temperature measurements of catalyst systems of the same type present in five reactors. These are averages obtained from a variety of repeat measurements taken over a long period of time. As can be seen from the figure, the light-off temperature measurement was carried out twice in total. Each measurement included a variety of repetitive cycles. As the diagram analysis shows, the tests carried out provide reproducible results.

The in the above description, in the drawings and in the claims disclosed features of the invention can be used in any combination for the Realization of the invention in its various embodiments be essential.

1

reactor

2

inlet end

4

inlet opening

6

outlet

8th

outlet opening

10

reactor vessel

12

cradle for the catalyst

14

catalyst sample

16

temperature sensor

18

cooling unit

20

heating unit

22

tempering

24

cavity the cooling unit

26

continuous cavity

28

cavity the heating unit

30

heating module

32

jacket

34

baffle

36

supply for reaction gas

38

inlet opening

40

contraption for testing the activity of catalysts

42

gas supply

44

Multiple valve

46

gas supply

48

gas discharge line

50

gas discharge line

52

analysis unit

54

Evaporation unit

56

heated container

58

discharge

60

Bypass sample loop

62

diluter

64

gas supply

Claims (53)

Reactor ( 1 for carrying out heterogeneous gas phase reactions or for testing catalysts for heterogeneous gas phase reactions, comprising - at least one reactor vessel ( 10 ) with an inlet end ( 2 ) and an outlet end ( 6 ), containing at least one receiving device ( 12 ) for a catalyst, at least one inlet opening ( 4 ) for the gas to be converted in the region of the inlet end ( 2 ) and at least one exit opening ( 8th ) for reacted gas in the region of the outlet end ( 6 ), - at least two units for cooling ( 18 ) of the reactor vessel, which at least in the section in which in the reactor vessel ( 10 ) the receiving device ( 12 ) is present for the catalyst, in each case in thermal contact with the reactor vessel ( 10 ), and - at least one, in particular at least two units for heating ( 20 ) of the reactor vessel ( 10 ), at least in the section in which in the reactor vessel ( 10 ) the receiving device ( 12 ) is present for the catalyst, in each case in thermal contact with the reactor vessel ( 10 ), the cooling and heating units ( 18 . 20 ) are arranged in such a way that the reactor vessel ( 10 ) at least in the region of the receiving device ( 12 ) for the catalyst, in particular substantially homogeneous, can be heated or cooled. Reactor ( 1 ) for heterogeneous gas phase reactions according to claim 1, characterized in that the reactor vessel ( 10 ) represents a tube. Reactor ( 1 ) according to claim 1 or 2, characterized in that the receiving device ( 12 ) represents a gas-permeable support or a gas-permeable container for the catalyst. Reactor ( 1 ) according to claim 3, characterized in that the gas-permeable support ( 12 ) is a sieve, preferably made of stainless steel, or a porous mat, in particular for a catalyst powder, or a holding element, in particular for a monolith. Reactor ( 1 ) according to one of the preceding claims, characterized in that the cooling and / or heating units ( 18 . 20 ) between the inlet end ( 2 ) and the outlet end ( 6 ) of the reactor vessel ( 10 ) are in thermal contact therewith. Reactor ( 1 ) according to one of the preceding claims, characterized in that the cooling unit ( 18 ) at least one cavity ( 24 ) with an inlet end and an outlet end for the passage of cooling gas, in particular compressed gas. Reactor ( 1 ) according to claim 6, further comprising at least one with the cavity ( 24 ) of the cooling unit ( 18 ) connected or connectable compressed gas line. Reactor ( 1 ) according to one of the preceding claims, characterized in that the heating unit ( 20 ) at least one cavity ( 28 ) for receiving at least one heating element. Reactor ( 1 ) according to one of the preceding claims, characterized in that the heating and cooling units ( 18 . 20 ) alternately around the reactor vessel ( 10 ) are arranged. Reactor ( 1 ) according to one of the preceding claims, characterized in that in each case adjacent heating and cooling units ( 18 . 20 ) are mostly not in contact with each other. Reactor ( 1 ) according to one of the preceding claims, characterized in that in each case adjacent heating and cooling units ( 18 . 20 ) by material recesses which at least partially between the inlet and the outlet end ( 2 . 6 ) of the reactor vessel ( 10 ) are separated. Reactor ( 1 ) according to any one of the preceding claims, further comprising a sheath ( 32 ), which is at least partially spaced from the cooling and heating units ( 18 . 20 ) and the reactor vessel ( 10 ) at least partially, in particular full circumference, surrounds. Reactor ( 1 ) according to claim 12, further comprising at least one baffle surface ( 34 ) for diverting the through the outlet end of the cavity ( 24 ) of the cooling unit ( 18 ) exiting cooling gas through the space between sheath ( 32 ) and the cooling and / or heating units ( 18 . 20 ). Reactor ( 1 ) according to one of the preceding claims, further comprising at least one supply line ( 36 ) for the gas to be converted to the reactor vessel ( 10 ), which at least partially in thermal contact with at least one heating unit ( 20 ) is present. Reactor ( 1 ) according to one of the preceding claims, further comprising at least one first temperature sensor ( 16 ), in particular a first thermocouple, within the reactor vessel ( 10 ). Reactor ( 1 ) according to claim 15, characterized in that the temperature sensor ( 16 ) in the region of the receiving device ( 12 ) of the catalyst is present so that the temperature in a catalyst sample is measurable. Reactor ( 1 ) according to one of the preceding claims, further comprising at least one second temperature sensor, in particular a second thermocouple. Reactor ( 1 ) according to claim 17, characterized in that the second temperature sensor in the wall of the reactor vessel ( 10 ) adjacent to the receiving device ( 12 ) of the catalyst is present. Reactor ( 1 ) according to one of the preceding claims, characterized in that the reactor vessel ( 10 ), the cooling unit ( 18 ) and / or the heating unit ( 20 ) are integral. Reactor ( 1 ) according to one of the preceding claims, comprising at least one tempering unit ( 22 ) containing at least two units for cooling ( 18 ) of the reactor vessel ( 10 ) and at least two units for heating ( 20 ) of the reactor vessel, wherein the tempering ( 22 ) at least in the section where in the reactor vessel ( 10 ) the receiving device ( 12 ) is in thermal contact with this reactor vessel ( 10 ) and the cooling and heating units ( 18 . 20 ) are arranged or arranged in such a way that the reactor vessel ( 10 ) in the region of the receiving device ( 12 ) for the catalyst, in particular substantially homogeneous, can be heated or cooled. Reactor ( 1 ) according to claim 20, characterized in that the cooling unit ( 18 ) at least one cavity ( 24 . 26 ) with an inlet end and an outlet end for the passage of cooling gas. Reactor ( 1 ) according to claim 21, further comprising at least one with the cavity ( 24 . 26 ) of the cooling unit ( 18 ) connected or connectable compressed gas line. Reactor ( 1 ) according to one of claims 20 to 22, characterized in that the heating unit ( 20 ) at least one cavity ( 28 ) for receiving at least one heating element. Reactor ( 1 ) according to one of claims 20 to 23, characterized in that the heating and cooling units ( 18 . 20 ) alternately in the temperature control unit ( 22 ) are arranged. Reactor ( 1 ) according to one of claims 20 to 24, characterized in that in each case adjacent heating and cooling units ( 18 . 20 ) are mostly not in direct contact with each other. Reactor ( 1 ) according to one of claims 20 to 25, characterized in that in each case adjacent heating and cooling ( 18 . 20 ) by material recesses which at least partially between the inlet and the outlet end ( 2 . 6 ) of the reactor vessel ( 10 ) are separated. Reactor ( 1 ) according to one of claims 20 to 26, characterized in that the temperature control unit ( 22 ) is essentially in one piece. Reactor ( 1 ) according to one of claims 20 to 26, characterized in that the temperature control unit ( 22 ) and the reactor vessel ( 10 ) are substantially integral. Reactor ( 1 ) according to one of the preceding claims, characterized in that the receiving device ( 12 ) for the catalyst to accommodate a catalyst amount in the range of 20 mg to 700 mg. Reactor ( 1 ) according to one of the preceding claims, characterized in that the cooling and heating units ( 18 . 20 ) are mounted substantially concentrically around the reactor vessel. Reactor ( 1 ) according to one of the preceding claims, further comprising a catalyst bed or a catalyst monolith on the receiving device. Reactor ( 1 ) according to one of the preceding claims, characterized in that the heating unit ( 20 ) comprises a heating resistor. Reactor ( 1 ) according to claim 32, characterized in that the heating resistor is the reactor vessel ( 10 ) at least in the region of the receiving device ( 12 ) for the catalyst and / or the cooling units ( 18 ) at least in the region of the receiving device ( 12 ) surrounds for the catalyst. Contraption ( 40 ) for testing catalysts for heterogeneous gas phase reactions, comprising at least one reactor ( 1 ) according to one of the preceding claims, at least one gas supply line ( 46 ) to the reactor ( 1 ), at least one product gas discharge line ( 48 ) from the reactor ( 1 ), at least one analysis unit ( 52 ) in operative connection with the product gas discharge line ( 48 ) and an evaluation unit in operative connection with the analysis unit ( 52 ). Contraption ( 40 ) according to claim 34, further comprising a control and / or regulating unit. Contraption ( 40 ) according to claim 34 or 35, further comprising an evaporator unit ( 54 ) for feeding water vapor and / or for feeding gaseous organic compounds in the gas supply line ( 46 ). Contraption ( 40 ) according to one of claims 34 to 36, further comprising a multiple valve ( 44 ), at least one first gas supply line ( 46 ) to the multiple valve ( 44 ), at least one second gas supply line ( 64 ) of the multiple valve ( 44 ) to at least one first reactor ( 1 ), at least one gas discharge line ( 48 ) from the first and / or second reactor ( 1 ) to the multiple valve ( 44 ) and at least one gas discharge line ( 50 ) of the multiple valve ( 44 ) to the analysis unit ( 52 ). Apparatus according to claim 37, further comprising at least one second or n'te gas supply line ( 64 ) of the multiple valve ( 44 ) to a second or nth reactor ( 1 ). Contraption ( 40 ) according to claim 37 or 38, further comprising at least one bypass sample loop ( 60 ), with the multiple valve ( 44 ) is in operative connection. Contraption ( 40 ) according to one of claims 34 to 39, further comprising a heatable container ( 56 ), in which the multiple valve ( 44 ), the bypass sample loop (s) ( 60 ), in each case at least in sections, the gas supply line ( 64 ) to the reactor (s) ( 1 ), the gas supply line (s) ( 46 ) to the multiple valve ( 44 ), the gas discharge line (s) from the reactor ( 1 ) to the analysis unit ( 52 ), the gas discharge line (s) ( 48 ) to the multiple valve ( 44 ), the gas discharge line (s) ( 50 ) of the multiple valve ( 44 ) to the analysis unit ( 52 ) and / or the outlet end ( 6 ) of the reactor or of the reactors ( 1 ) is present or present. Contraption ( 40 ) according to one of claims 34 to 40, characterized in that the discharge line ( 58 ) of a first reactor ( 1 ) with the inlet opening ( 4 ) of a second reactor ( 1 ) is connected or connectable. Contraption ( 40 ) according to claim 41, characterized in that the gas discharge line ( 58 ) of the second reactor or a nth reactor connected to the inlet opening of a third or (n + 1) 'th reactor or is connectable. Contraption ( 40 ) according to claim 41 or 42, characterized in that from the Gasabführleitung the first reactor and / or the Gasabführleitung the second reactor product gas via a, in particular controllable, branch line, directly or via the multiple valve, the analysis unit can be fed. Contraption ( 40 ) according to one of claims 34 to 43, further comprising a device ( 62 ) for diluting the product gas with a diluent gas upstream of the analysis unit ( 52 ). Use of the device according to one of claims 34 to 44 for testing the activity of catalysts for heterogeneous gas-phase reactions. Use of the device according to one of claims 34 to 44 for testing the, in particular temperature-dependent, activity of catalytic converters for internal combustion engines. Use according to claim 46, wherein with the device according to claims 34 until 44 the light-off temperature is determined. Method for determining the activity of catalysts for heterogeneous Gas phase reactions using a device according to one of the claims 34 to 44, comprising the steps: a) passing a to be implemented Gas through a first reactor at a first temperature in the on a receiving device a first catalyst for a heterogeneous Gas phase reaction is present, b) determining the temperature of the catalyst c) Feeding of the reactor leaving this, converted gas, in particular via a Multi-way valve, to an analysis unit, d) quantitative and / or qualitative determination of some or all components of the implemented gas, e) Allocating the qualitative and / or quantitative analysis results to the detected catalyst temperature in an evaluation unit and f) repeating steps a) to e) at different Temperatures and / or with a second or further reactor and / or a second and / or further catalyst. Method according to claim 48, characterized that the Temperature of the reactor at a speed in the range of 100 K / min. up to 200 K / min., preferably starting at the first temperature, is increased. Method according to claim 48 or 49, characterized that this the first reactor leaving the reacted gas completely or partially fed to a second reactor or n'ten reactor. Method according to claim 50, characterized in that that this the second reactor or nth Reactor leaving the reacted gas completely or partially a third Reactor and / or (n + 1) th Reactor supplied becomes. The method of claim 50 or 51, since characterized in that the heating rates for the first, second, third and / or n'ten reactor are different. Use of the device according to one of claims 34 to 44 for analyzing the activity and / or selectivity of catalysts for heterogeneous gas-phase reaction, especially in partial oxidation or in selective hydrogenation.