DE102008032097A1 - Test stand for parallel testing of catalysts under different flow conditions, has restrictors exhibit same flow resistance in one of reaction vessel subgroups and different flow resistance between reaction vessel subgroups - Google Patents

Abstract

The stand has two parallely arranged reaction vessel subgroups, where each subgroup has parallely arranged reaction vessels (101-110) comprising inlet pipes and discharge pipes. The inlet pipes have capillary restrictors (220-229) at each reaction vessel. The restrictors have a same flow resistance in one of the subgroups and a different flow resistance between the subgroups. One of the restrictors stays in thermal and/or physical contact with a heating and/or cooling unit. The restrictors are made from a ceramic material, glass or fused silica and/or fused quartz.

Description

The The present invention relates to the control of fluid streams in test stands, which are a plurality comprise reaction vessels arranged in parallel, which with a common all reaction vessels Fluid supply are connected. The invention Test stands are preferred in the field of high-throughput testing used by catalysts.

According to one Embodiment of the present invention comprises Test stand at least two subgroups arranged in parallel Reaction vessels, each subgroup in each case at least two, more preferably at least three, more preferably at least four parallel arranged reaction vessels includes. In this case, each reaction vessel comprises the at least two subgroups at least one supply line and at least a derivative. Here are all the reaction vessels the at least two subgroups with at least one all reaction vessels common fluid supply connected. Include the leads to each reaction tube each at least one restrictor within each subgroup preferably has the same flow resistance, wherein it is preferred that the flow resistance between different from the restrictors of the subgroups.

Prefers is in at least one subgroup at least one restrictor, preferably all restrictors in this subgroup, in thermal and / or physical contact with at least one means of heating and / or Cool, which sets the restrictor to each other Temperature heating (cooling) can, as the temperature of the Environment and as the temperature of the respective reaction vessel. Preferably, the restrictors are capillary restrictors.

The Use of restrictors, so of flow resistance or flow restrictors for regulating or Limiting fluid flows is known in principle. This Principle of fluid control or regulation based on the fact that a Differential pressure (often referred to as "pressure difference" or "pressure drop") over a restriction, so a flow resistance, given is determined and thus the flow of fluid through the restrictor or limited. Such a fluid restriction can with a Variety of different types of restrictors can be achieved for example, with needle valves (flow restrictors), mass flow controllers (controllable and / or controllable flow resistances), Aperture or capillary restrictors, so narrow tubes.

If a single fluid stream is to be divided into a plurality of separate individual streams, restrictors arranged in parallel are preferably used for this purpose. This basic principle of using restrictors for dividing fluid streams is for example in the US 2,583,177 disclosed. According to column 1, lines 35-50, this patent discloses a flow divider with the aid of which a fluid flow can be subdivided into a plurality of smaller subunits, wherein the distribution of the flows is effected by a corresponding number of parallel arranged capillary ducts. The parallel arranged capillary preferably have the same geometry (length, diameter) and thus the same restriction effect, ie the same flow resistance. Thus, a single incoming fluid flow is divided into a corresponding plurality of equal partial flows. The viscosity of the fluid medium should be the same in the paralleled capillary conduits so that the same flow resistance results in such a device. Usually, this means that the capillaries must be at the same temperature.

A similar device for dividing fluid streams is in the US 2 676 603 shown (see in particular 5 and related description at column 5, lines 13-28).

by virtue of the fact that by permanently installed in a plant capillary restrictors the flow resistance (essentially determined by the Diameter and the length of the capillary restrictors) and is fixed, but except by replacing the Capillary restrictors the educt flow through the individual capillary restrictors (and so that the inflow of fluid to possibly downstream Reactors) can not be separately controlled or regulated.

A further development of this basic principle of the use of restrictors for the distribution of fluid flows (in particular for uniform distribution) especially for test rigs with parallel reactors is, for example, in "Selective Catalytic Reduction ..." by L. Singoredjo et al., Catalysis Today 7 (1990) pages 157-165 disclosed. In 1 on page 159 and in the accompanying text below, a six-fold parallel reactor with a single common fluid supply is disclosed. The educt fluid is split into splitter "S" and, in interaction with the mass flow controllers "FC", regulated as flow resistances so that six equal flows enter the six parallel reactors. The mass flow controllers are each the largest flow resistance in the system and thus produce the necessary for equal distribution largest (and equal) pressure drop. Such an equal distribution of the rivers is particularly useful in the present case, since in the six parallel reactors six under different catalysts should be investigated under otherwise identical conditions. The advantage of such actively controllable and controllable mass flow controller is that not only a uniform distribution can be achieved, but also each desired (same) educt flows can be set or changed during the reaction. The setting of different flows through different parallel reactors is z. B. advantageous if the same catalysts in the context of kinetic studies under variable conditions, such as increasing GHSV to be investigated. On the other hand, such mass flow controllers are typically expensive and, in particular at high temperatures, possibly prone to failure.

Passive (ie non-controllable) restrictors in the form of capillary restrictors, pinhole diaphragms or microchannels for use in parallel test stands are in the WO 99/64160 disclosed as equivalent and interchangeable with active mass flow controllers (see, for example, page 7, lines 11-20 and page 13, lines 18-26). Also the WO 99/64160 relates to the parallel testing of catalysts under the same conditions.

in the Light of this prior art is one of the tasks of present invention in it, test stands for the To provide high-throughput research of catalysts as possible variable with regard to the setting of experimental parameters are, in particular also with respect to the educt gas flow through the reactors while at the same time sizing and the cost of the test stand should be improved.

A Embodiment of the present invention, which the solves the above task is a test stand, the at least two subgroups of reaction vessels arranged in parallel each subgroup being at least two, more preferably at least three, more preferably at least four arranged in parallel Includes reaction vessels. In this case, each reaction vessel comprises the at least two subgroups at least one supply line and at least a derivative. Here are all the reaction vessels the at least two subgroups with at least one all reaction vessels common fluid supply connected. Include the leads to each reaction tube each at least one restrictor within each subgroup preferably has the same flow resistance, wherein it is preferred that the flow resistance between different from the subgroups' restrictors (namely under otherwise identical conditions, d. H. same pressure and same Temperature). Preferably, the restrictors are to Kapillarrestriktoren.

According to one this preferred embodiment is for at least a subgroup, preferably per subgroup (in each case) at least a means for heating, which at least one or preferably common to all the restricor (s) of the respective subgroup (s). Preferably, at least one means for heating and / or cooling one subgroup independent of at least one other Means for heating and / or cooling the at least one other Subgroup adjustable to another temperature.

The Use of restrictors, with different flow resistances in at least two subgroups offers the advantage that in terms of the test stand a larger regime at different Flow rates or GHSV conditions (namely at least two) can be adjusted, although despite this variability in the flow through the reaction vessels one and the same Fluid supply can be used.

This is particularly vivid for a flowed through Represent capillary as a restrictor (capillary restrictor). The flow resistance, which such a restrictor opposes a fluid depends according to the Hagen-Poisenille-Law for laminar pipe flow on the viscosity of the flowing through From fluid, namely in the sense of "flow resistance = Viscosity × tube length × 1 / tube diameter to the fourth power ". Thus, therefore, by different Length and / or pipe diameter in a simple way the flow resistance set differently between the restrictors of two subgroups become.

According to one preferred embodiment is for a subgroup restrictors at least one means of heating (and / or cooling) before, which with at least one restrictor in thermal and / or physical contact. Preferably, in each case per subgroup in each case at least one means for heating / cooling, wherein at least one means of heating regardless of at least which is another means of heating, d. H. in particular another temperature adjustable. In this embodiment It is possible to restrict by different temperature to different flow resistance and to regulate rivers.

According to one For this preferred embodiment, all restrictors include each a means of heating, each independently can be controlled and / or regulated by one another. This embodiment allows each of the restrictors to a different flow resistance adjust and thus the rivers through the restrictors to regulate individually.

Of the particular advantage of being able to control a restrictor and to heat separately from the other components of the test stand and / or to cool, in particular restrictors of a subgroup, is that thereby the flow through the restrictors without movable mechanical components, such as those in valves or flow regulators, can be easily controlled, namely in that the temperature dependence of the viscosity exploited by fluids.

As already mentioned, the flow resistance depends by a restrictor of the viscosity of the flowing through Medium off. For example, the viscosity of gases increases with increasing temperature too (viscosity depends according to kinetic gas theory with the power 1/2 from the temperature T), d. H. the flow resistance increases with increasing temperature. Conversely, the viscosity decreases of liquids with increasing temperature (the viscosity of liquids is according to transport theory proportional to an activation factor and exponentially dependent from the quotient of activation energy and temperature). Thus sinks For liquids, the flow resistance at rising temperature. Overall, so for all fluids the flow resistance of restrictors over set a significant range by temperature change become. This possibility of adjusting and controlling Flow resistance and thus of rivers by a restrictor is especially for passive restrictors (ie such restrictors whose flow resistance in geometric sense is fixed) of advantage.

According to one preferred embodiment are all restrictors one subgroup in thermal and / or physical contact with a common first to all of these restrictors for Heating and / or cooling, whereas all restrictors the at least one other subgroup with one from the first agent for heating and / or cooling various second means for heating and / or cooling in thermal and / or physical Contact, which is preferably independent of the first Controlled and / or controlled means for heating and / or cooling can be.

These Embodiment basically requires only one means for heating and / or cooling per subgroup of restrictors (and accordingly only one rule / control circuit), is So very easy to set up and handle. Despite this comparatively simple construction can be done in the two subgroups Heating or cooling of the restrictors in one (and "non-heating" or "non-cooling" or "different-heating" or "different-cooling" in the other subgroup) at least two different fluid flows be adjusted through the reaction vessels, and in each case at the same educt flow (since all supply lines communicating with a common fluid supply).

According to one further alternative embodiment are all Restrictors of at least one of the at least two subgroups not in thermal and / or physical contact with an agent for heating and / or cooling, which the restrictors respectively could heat (cool) to another temperature, as the temperature of the environment and as the temperature of each Reaction vessels, whereas all Restrictors of at least one other subgroup with one of these restrictors common means of heating and / or cooling in thermal and / or physical contact.

In In a preferred embodiment, the restrictors have within each of the at least two subgroups with the same other Conditions (ie in particular the same temperature, pressure, etc.) each have the same flow resistance, whereas the Flow resistance of the restrictors of at least one Subgroup of the flow resistance of at least one other subgroup is at least 10% different, preferably around at least 20%, more preferably at least 50%.

Brief description of the figures:

1 shows a schematic representation of a catalytic apparatus, the ten parallel reaction vessels ( 101 . 102 , ... 110 ) and with two different types of controllable capillary restrictors ( 220 - 229 ) Is provided. The capillary restrictors ( 220 . 221 , ... 224 ) have a greater flow resistance at the same operating temperature and under the same pressure conditions than the capillary restrictors ( 225 . 226 , ... 229 ).

2 shows one 1 corresponding apparatus, the apparatus is additionally provided with pressure-holding gas and pressure build-up gas, which are indicated only schematically.

3 shows the schematic representation of a heatable Kapillarrestriktormoduls, which is five Kapillarrestriktoren is covered, wherein the Kapillarrestriktoren are screwed into the housing of the module. The five capillary restrictors may have the same lengths and inside diameters, or may differ in length and inside diameters.

4 shows the top view of a Kapillarrestriktormoduls, the capillary restrictors in a holding web ( 604 ), whereby these are secured against rotation.

In In a preferred embodiment, the restrictors are which are in the supply lines to the reaction vessels located, capillary restrictors. For the purposes of the present invention are capillary restrictors flow resistances, which are geometrically characterized in that they are inside essentially described as "tubular" can (ie a characteristic middle inner Diameter), and that this has a characteristic length which are at least a hundred times, preferably a thousand times, preferably two thousand times larger or ten thousand times is greater than the characteristic mean Diameter.

In Capillary restrictors is the pressure drop of a flowing through Fluid (ie the reduction in the volume flow) substantially by determines the so-called "Hagen-Poiseuille" law, d. H. the pressure drop increases substantially linearly with the length the capillary restrictors, rising substantially in the fourth Power with decreasing diameter of the capillary restrictors. The longer and / or the closer the capillary restrictors, the larger So is the pressure drop or the flow resistance.

Of the characteristic mean inner diameter of capillary restrictors is preferably at least a factor of two or three, preferably around the factor five or by a factor of ten less than the inner diameter of those pipelines that lead to these capillary restrictors or even from lead away the capillary restrictors, so the supply and discharge lines. The inner diameter of preferred capillary restrictors in the sense of the present invention is less than 250 microns, preferably the inner diameter is less than or equal to 150 μm and more preferably less than or equal to 100 microns.

The Length of the capillary restrictors is preferably in one Range from 0.05 to 30 m, with a length of 0.1 m to 15 m is preferred; particularly preferred is a length from 0.2 m to 6 m.

Kapillarrestriktoren with a diameter in the micrometer range and a length in the meter range can be within the meaning of the present invention particularly good in terms of pressure drop, d. H. of the generated Flow resistance, regulate or control, as the fluid over a large length heated or cooled can be, and thus a larger amount of fluid can be heated or cooled, so a major change can be achieved in the flow (the flow resistance itself is independent of volume and only hangs from the viscosity of the medium and the length and the diameter of the capillary restrictors). In that regard, it is preferable not to increase the flow resistance primarily reduces the diameter of the capillary restrictor, but primarily its length is increased becomes.

The flow resistance of a restrictor, in particular a capillary restrictor, can be calculated on the assumption of laminar tube flow in particular according to the following relationship: The flow resistance is the quotient of [viscosity of the flowing medium × length of the capillary] and [radius of the capillary to the fourth power] (see for example Chapter 3.3.3 of the Physics Textbook "Physics" by Gerthsen, Kneser and Vogel, 15th edition, Springer Verlag, 1986 ). The flow resistance is thus an intrinsic property of the restrictor, in particular, as in the case of the equation given above, of a capillary restrictor, and can be assigned to any capillary restrictor absolutely. If, for the purposes of the present invention, flow resistances are to be compared with one another, they should be compared under the same conditions, unless they are explicitly stated otherwise, in particular at the same pressure and at the same temperature.

Becomes in the sense of the present invention of a "same" flow resistance spoken, it is meant that the flow resistances compared in otherwise identical conditions (especially at the same Temperature and at the same pressure) with respect to one and the same flowing medium with a fault tolerance of ± 10% are the same.

in the According to the present invention, two flow resistances regarded as "different" when these are themselves under the conditions given above, ie in particular when flowing through the same fluid and the same Pressure and same temperature in the flow resistance by at least 10%, preferably by at least 20%, more preferably differ by at least 50%, and more preferably by at least 100%.

Similar Properties as with capillary restrictors can also be achieved by means of to achieve microfabricated channels, incorporated into metallic, ceramic or polymeric moldings were. Such production methods are known to the person skilled in the art and For example, laser ablation or microetching include. Because such microchannels in terms of geometry and Acts as a restrictor to the pipelined capillary restrictors correspond, such micro-channels are within the meaning of the present Also considered as "capillary restrictors".

In a preferred embodiment, capillary restrictors used are glass capillary restrictors, ceramic capillary restrictors or stainless steel capillaries larrestriktoren used, wherein the use of glass capillary or ceramic Kapillarrestriktoren is preferred.

Especially preferred are capillary restrictors made of an "elastic" ceramic Material, ie a ceramic material with a modulus of elasticity ("Young's Modulus") less than 90 GPa, preferably less than 70 GPa, exist. These capillary restrictors exist preferably from "pulled" glass and thereby in particular preferably made of "fused silica" or "fused quartz" or Mixtures of these and other ceramic materials. such ceramic capillary restrictors are actually on another technical field, namely the field of chromatography as support materials for gas chromatographic Separation columns, known. Due to the high commercial Relevance of chromatography procedures are these capillary restrictors Well developed and cost-effective available on the market. It has now been shown that this is actually from another application also derived from ceramic capillary restrictors the application in test rigs for high-throughput testing of catalysts are suitable.

such Restrictors, in particular fused silica capillary restrictors can also be well wound on rolls or turn into spirals ("Wound pillars"). Wound capillaries will be through the column length, the number of turns per unit length and the mean diameter of a turn described. Preferably, the windings have a mean diameter ranging from 5 cm to 30 cm. Wound or twisted capillary restrictors can be particularly by the heating effect of adjacent windings heat effectively and save space.

In a preferred embodiment comprises at least one Means for heating and / or cooling (also: "heating element") at least one temperature sensor ("temperature sensor") and / or comprises at least one restrictor, preferably capillary restrictor, at least a temperature sensor.

In In a preferred embodiment, the means are for heating and / or cooling and the temperature sensors of at least two or more capillary restrictors and / or at least one subgroup of capillary restrictors each with the same regulatory relationship Control device, it being preferred that the means for Heating and / or cooling and temperature sensors for in each case at least four capillary restrictors, each with the same Temperature control or control device connected are. In particular, it is preferred that the means for heating and / or cooling and temperature sensors of at least eight Capillary restrictors, each with the same temperature control or control device are connected.

To the Heating and / or cooling of the capillary restrictors in the context of the present invention preferably means for heating and or cooling used, the means for heating preferably heating foils, heating plugs, heating cords, heating tapes or Include heater housing. Heating tapes or heating cords For example, they can encapsulate capillary restrictors or rotated together with the capillary restrictors to a coil become. It is also preferred that a capillary restrictor first regardless of the means of heating turned into a coil and subsequently encased by the heating element.

medium for cooling are preferably via a heat exchanger, For example, fluid cooling realized.

in the In accordance with the present invention, means for heating as a "means for changing the temperature "includes So also a means for cooling or for heating and Cool.

For the case of using metal capillary restrictors as restrictors These are preferably directly from electrical power flowed through, so the capillary restrictors themselves as a means can act for heating. Furthermore, it is preferred position the capillary restrictors in a metal jacket tube and this jacket tube - analogous to the aforementioned Metal capillary restrictors - directly to a power source to connect and to use as a means of heating. Within of the heating jacket tube should preferably capillary restrictors made of electrically insulating materials.

Kapillarrestriktoren of electrically insulating materials, for example fused silica capillary restrictors, are preferably with a temperature resistant, electric provided conductive layer, which can then be used for heating.

If the capillary restrictors, their outer surface of electric current is passed through, curled up to wrap are, the individual turns are preferably both side by side as well as layer by layer electrically isolated from each other so that by electrical bridging no unheated Can form loops. Preferably, the electric Isolation a coating of a heat resistant Paint used.

In a preferred embodiment, the capillary restrictor or the metal tube enclosing the capillary restrictor is used both as Used means for heating and as a temperature sensor, under the proviso that the metal has a temperature-dependent resistance.

in the In accordance with the present invention, it is also preferred to use the capillary restrictors indirectly via heat exchangers, for example, flow around with a fluid, to heat or cool. Also a heating over Thermal radiation is preferred.

The Temperature of the individual capillary restrictors is preferably recorded by temperature sensors, which are in direct contact with at least part of the restrictor, for example a capillary wall, stand. It is also possible that a single capillary restrictor is provided with a plurality of temperature sensors, or the heating element even the temperature sensor is.

The Temperature of the individual capillary restrictors may preferably varies in a range from room temperature to 350 ° C become. If the capillary restrictor made of a heat-resistant material consists of, for example, stainless steel, so the capillary restrictor can also be operated at temperatures above 350 ° C. Become capillary restrictors preferably also cooled.

According to one preferred embodiment, the from the reaction vessels effluent reaction products and / or (unreacted) starting materials in at least one analyzer (eg a hot gas flow analyzer) analyzed. It is preferred that the outflows of the individual reaction vessels, also of individual Reaction vessels of individual subgroups, respectively can be analyzed separately, for example by Use of at least one selection valve, which is the outflow of each reaction vessel can turn on at least one detector while the Outflow of the other reaction vessels not analyzed or otherwise analyzed. The use of arranged in parallel Detectors as an analyzer is preferred. Further preferred Detectors may be: ND-IR (non-dispersive IR spectrometer), IR (Dispersive IR Spectrometer), GC (Gas Chromatography), GC-MS (Gas chromatograph with mass spectrometer coupling), MS (mass spectrometer), UV (Ultraviolet Spectrometer), FID (Flame Ionization Detector), WLD (thermal conductivity detector), heat capacity detector, ECD (electron capture detector for components with strong electronegative groups), PID (photoionization detector), PED (photoemission detector).

Of the Analyzer is preferably connected to a process control, where possible in a preferred embodiment is the flow resistance of individual capillary restrictors by adjust, calibrate or regulate that the Signal of the analyzer from the process control to the regulation respectively Control at least one means for heating and / or cooling is used to by settings of a predetermined or calculated heating or cooling capacity desired Amounts of fluid flow passing through the capillary restrictors to control or regulate.

The Adjustment of the flow rate per restrictor is preferably carried out over a feedback circuit with the analyzer, on preferably before the actual catalytic examination started becomes. In a preferred embodiment, one serves the reaction uninvolved gaseous substance (a so-called "Tracerkomponente"), on which the analyzer reacts selectively as a reference fluid for the adjustment of the flow resistance by temperature control.

In a further preferred embodiment, the present invention relates to a capillary reactor module ( 07 ) as well as its use. In this case, the capillary reactor module is preferably a solid frame in which two or more, preferably four or more, capillary restrictors are installed against rotation and grouped next to one another. Such a module is characterized by a high degree of flexibility and easy handling in connection with assembly and maintenance work to be carried out on a catalytic converter.

at Capillary restrictors are often sensitive Components due to extreme chemical and thermal Conditions as well as high pressures of heavy use subject and therefore prone to wear and tear and aging can be. The term "extreme" chemical Conditions implies that the capillary restrictors are reactive may be exposed to a change cause surface structure or blockage of the restrictor can lead by deposits.

The easiest accessibility and interchangeability of the capillary restrictors is of particular use in the maintenance of catalytic converters. When using fused silica capillary restrictors, it must be taken into account in particular that the ends of the fused silica capillary restrictors (which are preferably sealed by means of graphite seals and fastened to metal fittings of pipes or valves) are delicate and filigree. In particular, when installing and removing the capillary restrictors may cause defects and / or blocking and consequent disturbances or leaks. The defects are often difficult to find and a aufwendi Troubleshooting can lead to delays in the commissioning of the entire test stand. Such defects, if unnoticed, can also jeopardize the data quality of the measurements.

in the According to the present invention, it is preferred, as described above, that a catalysis test stand at least two subgroups of two, comprises four, eight or more reaction vessels, So in total with a large number of capillary restrictors Is provided. This also shows that an improved and easy handling of the capillary restrictors of great economic Interest is. For example, a test bench that over has sixteen parallel reactors, with 16 up to 64 capillary restrictor elements (da Capillary restrictors not only, as described above, to reaction space input side fluid control can be used, but in many applications also reaction output side for pressure reduction or for the uniform distribution of a holding gas), wherein this then twice as many capillary restrictor tails and thus also twice as many connection points, d. H. 32 to 128 joints, between capillary leads and connecting leads has.

The Kapillarrestriktoren are therefore according to a preferred embodiment of the present invention provided in capillary restrictor modules, which are hereby is compact frame, the two or more capillary restrictor elements and at least one means for heating and / or per module Cooling and at least include a temperature sensor. These capillary restrictor modules preferably correspond to the "subgroups" of Restrictors as described above. In every capillary restrictor module is preferably each individual restrictor element with its own Means for heating and / or cooling and / or its own Temperature sensor equipped.

According to one alternative embodiments include per capillary restrictor module two or more capillary restrictors each have a means for heating and / or Cool respectively all capillary restrictors a common Means for heating and / or cooling.

The Capillary restrictor module has the advantage of being this is a compact and robust component that is easy to use handle, as it is preferably by means of metal fittings or quick release couplings in a time-saving and trouble-free Way in the catalytic converter can be attached.

The Testing and testing of the capillary reactor module on its Functioning as well as the determination of its technical Properties can already before its installation in the catalytic converter under With the help of a separate test stand, so that the time for the construction or maintenance of the catalytic converter considerably can be shortened. This separate test stand is easier under construction, so that the measuring time at the catalytic converter itself be minimized for the testing of capillary restrictors can.

In a preferred embodiment, two or more capillary restrictors become a module ( 07 ), preferably four or more capillary restrictors. According to a preferred embodiment, the frame comprises ( 600 ) or the housing of the module a good heat-conducting material, so that over the block also a temperature of the capillary restrictors is possible. The temperature of the block and thus also the capillary restrictors therein is preferably carried out on the side surfaces mounted heating plates. The module can also be heated by cartridge heaters inserted in the block. For heating the usual control circuits are used in the art.

The capillary module ( 07 ) preferably comprises a metal block. In a preferred embodiment, the metal block is made of a good heat conducting material, such as copper, aluminum or brass. The largest surfaces are preferably parallel to each other.

In the metal block are in the plane of the largest surfaces ("side surfaces") preferably grooves ( 601 ) brought in. These grooves serve to accommodate capillary restrictors, for example made of steel, plastic or quartz.

In the planes of the smaller surfaces ("upper or" lower surface "), an even number of threaded bores is preferably introduced. The holes are used to hold one screwdriver each ( 605 . 605 ' ). There are preferably two of the threaded holes connected to a channel open on one side. With the screwdriver, the fluidic connection of the module takes place on one side. The capillary restrictor (s) are sealed with the side turned into the thread of the metal block. Thus, when installing the Kapillarrestriktormoduls no longer the (possibly filigree) Kapillarrestriktoren itself, but rather only the screwdriver are sealed.

If in the grooves free spaces between two adjacent capillary restrictors should occur, it is preferable to use a composite (for example Silicone) to fill, thus a direct, thermally conductive Contact with the capillary restrictors is ensured.

In a preferred embodiment, in each case at least one screwdriver between the two threads regularly regularly divided and at least triangularly arranged surfaces, wherein the surfaces are preferably quadrangular and more preferably hexagonal (see 4 ). For hard sealing materials that are harder than graphite, it may be necessary to prevent the screwdriver from twisting at angles smaller than 30 °. In this case, it is useful if the screwdriver is equipped with a larger number of holding surfaces. These surfaces are for installation with a wrench and after completion of the recording as anti-rotation (see ( 604 ) in 4 ).

If, for production reasons, it should be necessary to guide the groove into the bottom of the bore, it is further preferred to use a pressure distribution disc ( 602 . 602 ' ) to the bottom of the threaded hole. The fluidic sealing of a capillary restrictor in the bottom of the bore preferably takes place via sealing cones (US Pat. 603 . 603 ' ) of graphite or other sealing material typically used by a person skilled in the art for the production of compression seals. Preferred materials are Teflon, fiber-densified polymers or PEEK. The actual sealing takes place via the compression of the sealing cone generated by the screwing force. After the screwdriver ( 605 ) were tightened with the torque required for compression of the sealing cones, they are by applying an anti-rotation ( 604 ) secured against further rotation and thus against excessive tightening or against loosening during assembly of the fluidic inlets and outlets.

In Regarding the supply lines and discharges leading to the module and from the Module away, they will be in accordance with a preferred embodiment provided with quick couplings.

Catalytic test stands, in which the capillary restrictors according to the invention and capillary restrictor modules are preferred, are preferably laboratory usually tested with between 0.1 g and 50 g of catalyst become. It is preferred that the invention Capillary restrictors in conjunction with catalytic test stands to verwärden in which 0.2 g to 2 g of catalyst are tested, preferably less than 2 g of catalyst. However, it is advantageous that the Kapillarrestriktormodule invention in principle also suitable for catalytic test stands, in which - relative to the laboratory scale - relative large quantities of catalyst are tested.

One in practice a common problem in use of capillary restrictors concerns the fact that the channels the Kapillarrestriktoren optionally be easily blocked without being immediately noticeable. This leads to a greater variation respectively systematic shifts in measurement data quality. Modularization and heatability of capillary restrictors according to the present invention helping to better characterize and monitor their properties can be, so that an improved intervention in the occurrence of mistakes is possible.

One another advantage over the use of capillary restrictors the use of active mass flow controllers in test stands is that the capillary restrictors in the inventive Construction at higher temperatures and pressures can be operated as this with active mass flow controllers the case is.

It is thereby possible, the catalytic tests under Operating conditions to control, which otherwise technically only very difficult to realize.

In Another preferred embodiment of the present invention Invention provides the mechanical bending of capillary restrictors another parameter, with the help of the flow through the capillary restrictors in addition to the thermal control or alternatively to the thermal control in a certain area can be controlled. Bending consists either in the reversible Form change from a stretched to a wound Capillary restrictor or changing the winding number or the winding diameter. Such a "bending" becomes preferably in connection with "elastic" capillary restrictors (Young's modulus below 90 GPa or 70 GPa) used, in particular with "fused-silica" capillaries.

01, 02 ... 06

adjustable or controllable capillary restrictors

07

Kapillarrestriktormodul

21

medium for heating

31

capillary

51

Mulitportventil

52

analyzer

54

output line to the exhaust air

55

analysis device side Exhaust air line, wherein a connection to the line (54) may be present can

56

electronic Connecting line to the controller or control program of apparatus

57

regulator or control unit for controlling or controlling the heatable capillary restrictors

101-110

reaction vessels

201-210

interconnectors between the controllable or controllable capillary restrictors and the reaction vessels

220-229

controllable or controllable capillary restrictors

300

heating element

301 304

connections

302 303

acceptance points

401-410

leads to the controllable or controllable capillary restrictors

501-510

interconnectors the temperature sensors to a controller or control box

600

casing (Frame) with cutout for capillary restrictors and receiving areas with thread

601 601 '

groove or recesses

602 602 '

insertion elements (for example, washers)

603 603 '

sealing element with passage for capillary restrictor

604 604 '

holding web (Rotation)

605 605 '

two-sided Screw thread (can also at least on one side with quick coupling or bayonet closure be provided)

606 606 '

sealing element with execution for administration

607 607 '

screw with bushing (union nut)

608 608 ', 609' '

corresponds to 605 ) (here with 6eckiger mother and 12eckiger screw)

701-710

supply lines for operating the means of heating, with the capillary restrictors keep in touch

801-810

receipt items for the temperature sensors on the controller or on the control box

901-910

starting positions from the controller to the heating elements of the capillary restrictors

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - US 2583177 [0005]
• - US 2676603 [0006]
• WO 99/64160 [0009, 0009]

Cited non-patent literature

• - "Selective Catalytic Reduction ..." by L. Singoredjo et al., Catalysis Today 7 (1990) pages 157-165 [0008]
• - Chapter 3.3.3 of the physics textbook "Physics" by Gerthsen, Kneser and Vogel, 15th edition, Springer Verlag, 1986 [0032]

Claims (13)

Test rig for parallel testing of catalysts under different flow conditions, wherein the test stand comprises at least two subgroups of reaction vessels arranged in parallel, each subgroup comprises at least two or three or four parallel arranged reaction vessels and each reaction vessel of the at least two subgroups at least one supply line and at least one derivative and all the reaction vessels of the at least two subgroups are connected to at least one fluid supply common to all reaction vessels, the supply lines to each reaction vessel each comprising at least one restrictor, characterized in that the restrictors have the same flow resistance within a subgroup under the same other conditions, between at least however, two subgroups have a different flow resistance. Test stand according to claim 1, characterized characterized in that the restrictors are capillary restrictors. Test stand according to claim 1 or claim 2, characterized characterized in that in at least one subgroup at least one Restrictive in thermal and / or physical contact with at least one Means for heating and / or cooling stands, which is the restrictor each can heat to a different temperature or cool, as the temperature of the environment and as the temperature of the respective reaction vessel. Test stand according to one of the preceding claims, characterized in that at least two means for heating and / or Cooling present, each with at least one restrictor in thermal and / or physical contact. Test stand after and / or cooling claim 4, characterized in that at least one means for heating regardless of the at least one other means of heating and / or cooling, d. H. adjustable to a different temperature is. Test stand according to at least one of the preceding claims, characterized in that each subgroup has at least four or more at least six reaction vessels and at least comprises four or at least six restrictors. Test stand according to claim 3, characterized that all restrictors of at least one subgroup each one all These heaters include common means for heating. Test stand according to one of the preceding claims, characterized in that the flow resistance of Restrictors of a subset of the flow resistance the at least one other subgroup differ by at least 10% is, preferably at least 20%, more preferably at least 50%. Test stand according to at least one of the preceding claims, characterized in that the restrictors capillary restrictors are that have a characteristic length which at least five hundred times larger than the characteristic mean diameter. Test stand according to claim 9, characterized that the inner diameter of the capillary restrictors is smaller or is equal to 250 microns and the length of the capillary restrictors from 1 m to 6 m. Test stand according to at least one of the claims 2 to 10, characterized in that the capillary restrictors from a ceramic material having a modulus of elasticity or Young's modulus less than 90 GPa, preferably less than 70 GPa, and preferably consist of drawn glass, and further preferably from fused silica or fused quartz consist. Test stand according to at least one of the preceding Claims, characterized in that at least one means for heating and / or cooling and / or at least one restrictor comprises at least one temperature sensor. Test stand according to at least one of the preceding Claims, characterized in that the from the reaction vessels effluent reaction products and / or unreacted Educts and / or specially added "tracer" fluids be analyzed in at least one analyzer and the controller and / or regulation of the test stand is suitable for the flow resistance of single capillary restrictors to calibrate or to regulate, in that the signal of an analyzer from the control and / or regulation for regulation or control used at least one means for heating and / or cooling is to by setting a predetermined or calculated Heating or cooling power predetermined amounts of fluid flow, which flows through the capillary restrictors to control or to regulate.