WO2010003661A1

WO2010003661A1 - Test stand with controllable or regulable restrictors

Info

Publication number: WO2010003661A1
Application number: PCT/EP2009/004945
Authority: WO
Inventors: Andreas Mueller; Armin Brenner; Oliver Koechel; Matthäus KIELBASA; Armin Lange De Oliveira
Original assignee: Hte Aktiengesellschaft, The High Throughput Experimentation Company
Priority date: 2008-07-08
Filing date: 2009-07-08
Publication date: 2010-01-14
Also published as: EP2349569A1

Abstract

The present invention relates to the control or regulation of fluid flows in test stands which comprise a multiplicity of reaction vessels which are arranged in parallel and which are connected to a fluid supply which is common to at least two reaction vessels. The test stands according to the invention are preferably used in the field of high-throughput testing of catalytic converters. Here, the test stand comprises at least two reaction vessels which are arranged in parallel. Here, each reaction vessel comprises at least one inlet line and at least one outlet line. Here, all the reaction vessels are connected to at least one fluid supply which is common to all the reaction vessels. The inlet lines to each reaction vessel comprise in each case at least one restrictor which preferably has in each case the same flow resistance. Here, each restrictor is in thermal and/or physical contact with at least one heating (cooling) means which can heat (cool) the restrictor in each case to a temperature which differs from the temperature of the environment and from the temperature of the respective reaction vessels.

Description

Test stand with controllable or adjustable restrictors

The present invention relates to the control or regulation of fluid streams in test stands, which comprise a multiplicity of reaction vessels arranged in parallel, which are connected to a fluid supply common to all reaction vessels. The test stands according to the invention are preferably used in the field of high-throughput analysis of catalysts.

According to one embodiment of the present invention, the test stand comprises at least two, preferably at least four, more preferably at least six reaction vessels arranged in parallel. In this case, each reaction vessel comprises at least one feed line (upstream of the reaction vessel, seen in the direction of flow of the supplied fluid) and at least one discharge line (downstream of the reaction vessel, viewed in the direction of flow of the supplied fluid). In this case, all the reaction vessels of the test stand are connected to at least one fluid supply common to all the reaction vessels. The supply lines to each reaction vessel each comprise at least one restrictor which preferably has the same flow resistance in each case. At least one restrictor is in thermal and / or physical contact with at least one means for heating and / or cooling, which in each case has the restrictor (or the restrictors, if two or more restrictors are connected to at least one heating / cooling means) a different temperature can heat (cool) than the temperature of the environment and as the temperature of the respective reaction vessel.

For the purposes of the present invention, the restrictors are preferably capillary restrictors.

The use of restrictors, that is to say of flow resistances or flow restrictors for regulating or limiting fluid flows, is known in principle. This principle of fluid control is based on that a differential pressure (often referred to as "pressure difference" or "pressure drop") via a restriction, ie a flow resistance, is specified and thus the flow of fluid through the restrictor is determined or limited. Such fluid restriction can be achieved with a variety of different types of restrictors, such as needle valves (flow restrictors), mass flow controllers (controllable and / or variable flow resistors), pinhole diaphragms or capillary restrictors, ie 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 disclosed, for example, in US Pat. No. 2,583,177. 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 Kapillarleitungen preferably have the same

Geometry (length, diameter) and thus the same restriction effect, so 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 parallel capillary lines, 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 splitting fluid streams is shown in US 2 676 603 (see in particular Figure 5 and related description in column 5, lines 13-28).

Due to the fact that the flow resistance (essentially determined by the diameter and the length of the capillary restrictors) is predetermined and fixed by capillary restrictors permanently installed in a system, the educt flow through the individual capillary restrictors (and thus also the capillary restrictors) can be changed except by exchanging the capillary restrictors Inflow of fluid to optionally downstream reactors) can not be separately controlled or regulated. A further development of this basic principle of using restrictors for distributing fluid streams (in particular for uniform distribution) especially for parallel reactor test stands is, for example, in "Selective Catalytic Reduction ..." by L. Singoredjo et al., Catalysis Today 7 (1990) pages 157 - 165. A six-fold parallel reactor with a single common fluid supply is disclosed in Figure 1 on page 159 and in the accompanying text The educt fluid is split in the splitter "S" and in interaction with the mass flow controllers "FC" as flow resistances Thus, six equal flows enter the six parallel reactors, with the mass flow controllers representing the largest flow resistances in the system and thus producing the largest (and equal) pressure drop required for equal distribution in the six para llelen reactors six different catalysts under otherwise identical conditions to be investigated. The advantage of such actively controllable and controllable mass flow controller is that not only an equal 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 advantageous, for example, if identical catalysts are to be investigated within the framework of kinetic investigations under variable conditions, for example increasing GHSV. 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 disclosed in WO 99/64160 as equivalent and interchangeable with active mass flow controllers (see for example page 7, lines 11-20 and page 13, lines 18-26). WO 99/64160 also relates to the parallel investigation of catalysts under the same conditions.

In the light of this prior art, one of the objects of the present invention is to provide test stands for the high-throughput research of catalysts which are as variable as possible in the setting of experimental parameters, in particular also with respect to the educt gas flow through the - A -

Reactors, while at the same time the dimensions and costs of the test stand should be kept low.

The tasks mentioned here and further objects are achieved according to one embodiment in that the test stand comprises at least two, preferably at least four, more preferably at least six, parallel arranged reaction vessels. In this case, each reaction vessel comprises at least one feed line (upstream of the

Reaction vessel, seen in the flow direction of the supplied fluid) and at least one discharge (downstream of the reaction vessel, seen in the flow direction of the supplied fluid). In this case, all the reaction vessels of the test stand are connected to at least one fluid supply common to all the reaction vessels. The leads to each

Each reaction vessel comprises at least one restrictor, which preferably has the same flow resistance in each case. In this case, at least one restrictor is in thermal and / or physical contact with at least one means for heating and / or cooling, which in each case heat the restrictor to a different temperature

(Cooling) can be considered the temperature of the environment and the temperature of the particular

Reaction vessel.

Preferably, the restrictors are capillary restrictors.

Preferably, at least two restrictors are in thermal and / or physical contact with at least one heating and / or cooling means which can heat (restrict) the restrictor to a different temperature than the ambient temperature and the temperature of the respective reaction vessel.

The particular advantage of controlling and / or cooling a restrictor in a controlled and separate manner from the other components of the test rig is that it allows the flow through the restrictors without moving mechanical components, such as those in valves or flow regulators, to be easily controlled can, primarily by the fact that the temperature dependence of the viscosity of fluids is utilized.

This can be illustrated particularly clearly for a capillary flowed through as a restrictor (capillary restrictor). The flow resistance, which such a restrictor contrary to a fluid depends, according to the Hagen Poiseuille law for laminar pipe flow of the viscosity of the fluid flowing through, namely in the sense of "flow resistance = viscosity x pipe length x 1 / pipe diameter to the fourth power". For example, for gases, the viscosity increases with increasing temperature (viscosity depends on kinetic gas theory with the power 1/2 of the temperature T), ie, the flow resistance increases with increasing temperature. Conversely, the viscosity of liquids decreases with increasing temperature (according to transport theory, the viscosity of liquids is proportional to an activation factor and exponentially dependent on the quotient of activation energy and temperature). Thus, in liquids, the flow resistance decreases with increasing temperature. Overall, therefore, the flow resistance of restrictors can be adjusted over a significant range by temperature change for all fluids. This possibility of Einregeins and controlling flow resistance and thus of rivers by a restrictor is especially for passive restrictors (ie such restrictors whose flow resistance in the geometrical sense is fixed) advantage.

According to a preferred embodiment, at least two means for heating (and / or cooling) are present per test stand, which are each in thermal and / or physical contact with at least one restrictor. Furthermore, at least one means for heating / cooling is independent of at least one other means for heating / cooling, i. in particular adjustable to a different temperature. In this embodiment, it is possible to control two or more identical restrictors in a test stand with a single Eduktfluidzufuhr by applying different temperatures to different flow resistance and thus flows.

According to a preferred embodiment, all restrictors each comprise a means for heating, which are each independently controllable and / or controllable. This embodiment makes it possible to set each of the restrictors to a different flow resistance and thus the flows or to control the GHSV individually by the restrictors, but without the need for mechanically moving parts, and all this using a single fluid supply for all reaction vessels. For all embodiments, it is particularly preferred to use capillary restrictors as restrictors, since these are particularly cost-effective and in combination with the means for heating / cooling also allow an "active" flow control.

The (capillary) restrictors controllable or controllable via means for heating and / or cooling can preferably also be integrated into at least two subgroups of reaction vessels arranged in parallel, each subgroup in each case comprising at least two, more preferably at least three, more preferably at least four reaction vessels arranged in parallel includes. In this case, each reaction vessel of the at least two subgroups comprises at least one supply line and at least one discharge line. In this case, all reaction vessels of the at least two subgroups are connected to at least one fluid supply common to all reaction vessels. The feed lines to each reaction vessel each comprise at least one restrictor which preferably has the same flow resistance within each subgroup, it being preferred that the flow resistance between the restrictors of the subgroups is different (under otherwise identical conditions, ie the same pressure and temperature ). In at least one subgroup, at least one restrictor is in thermal and / or physical contact with at least one means for heating and / or cooling which can heat (restrict) the restrictor to a different temperature than the ambient temperature and the temperature of the respective reaction vessel. Preferably, the restrictors are capillary restrictors.

Brief description of the figures:

FIG. 1 shows different embodiments for capillary restrictors: capillary restrictor (01) comprises six windings, capillary restrictor (02) three windings and capillary restrictor (03) two windings; (04), (05) and (05 ') are capillary restrictors whose input and output

Output line are arranged on opposite sides, whereas (06) shows a Kapillarrestriktor whose input and output line is arranged on the same side. Figure 2 shows a schematic section through a Kapillarrestriktor (31), which is enclosed by a temperature sensor (501) comprising means for heating (21), wherein the conduit (701) is the connecting line to the heating controller or for control.

FIG. 3 shows a schematic representation of a heatable capillary restrictor module comprising five capillary restrictors, the capillary restrictors being screwed into the housing of a capillary restrictor module. The five capillary restrictors can have the same lengths and inside diameters or in length and the

Inner diameters differ from each other.

FIG. 4 shows the top view of a capillary restrictor module, wherein the capillary restrictors are fastened in a holding web (604), whereby they are secured against rotation.

Figure 5 shows the EMSR scheme of a capillary heating control equipped with a heating jacket.

FIG. 6 shows a schematic representation of a catalytic converter which comprises ten reaction vessels (101, 102,... 110) connected in parallel and which is equipped with two different types of controllable capillary restrictors (220-229). The capillary restrictors (220, 221, ... 224) have a greater flow resistance than the capillary restrictors (225, 225) at the same operating temperature and under the same pressure conditions.

226, ... 229).

FIG. 7 shows an apparatus corresponding to FIG. 6, wherein the apparatus is additionally provided with pressure-holding gas and pressure-buildup gas, which are indicated only schematically.

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

In capillary restrictors, the pressure drop of a flowing fluid (ie the reduction in the volume flow) is essentially determined by the so-called "Hagen-Poiseuille" law, ie the pressure drop increases substantially linearly with the length of the capillary restrictors and increases substantially to the fourth power As the diameter of the capillary restrictors decreases, the longer and / or narrower the capillary restrictors, the greater the pressure drop or flow resistance.

The characteristic mean inner diameter of capillary restrictors is preferably at least by a factor of two or three, preferably by a factor of five or by a factor of ten smaller than the inner diameter of those pipelines leading to these capillary restrictors or also away from the capillary restrictors, ie the zu and derivatives. The internal diameter of preferred capillary restrictors in the context of the present invention is less than 250 μm, preferably the internal diameter is less than or equal to 150 μm and more preferably less than or equal to 100 μm.

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

Capillary restrictors with a diameter in the micrometer range and a length in the meter range can be within the meaning of the present invention particularly well with respect to the pressure drop, ie the flow resistance generated, regulate or control, since the fluid is heated or cooled over a long distance can, and thus a larger amount of fluid can be heated or cooled, so a major change in the flow can be achieved (the flow resistance itself is independent of the volume and depends only on the viscosity of the medium and the length and Diameter of the capillary restrictors). In that regard, it is preferred that to increase the flow resistance not primarily the diameter of the capillary restrictor is reduced, but primarily its length is increased.

For a reliable effect of a capillary restrictor as a flow resistance, it is advantageous if the capillary and the fluid contained in the capillary experience the most uniform possible through-heating. When heating capillaries, there can very easily be the risk that inhomogeneities of the heating (= tempering) result from different thermal contact between the heating element and the capillary. For long restrictors, a statistical averaging is done in this regard and, consequently, this shortcoming does not (so much) affect the overall resistance of the restrictor. The radial heating takes place at inner diameters of the capillary up to 500μm within a capillary length of a few centimeters. Among other things, this is one reason why the use of capillaries is particularly advantageous if their diameter is less than 500 μm.

The flow resistance of a restrictor, in particular of a capillary restrictor, can be calculated assuming laminar tube flow in particular according to the following relationship: The flow resistance is the quotient of [viscosity of the flowing medium x 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.

If a "same" flow resistance is used in the context of the present invention, it is meant that the flow resistances compared with otherwise identical conditions (in particular at the same temperature and at the same pressure) with respect to one and the same medium flowing through them with a fault tolerance of ± 10% are the same. For the purposes of the present invention, two flow resistances are regarded as "different" if they are at least 10%, preferably at least 20%, under the conditions given above, ie in particular when flowing through the same fluid and at the same pressure and the same temperature in the flow resistance. , more preferably by at least 50%, and more preferably by at least 100%.

Similar properties as with capillary restrictors can also be achieved by means of microfabricated channels, which have been incorporated into metallic, ceramic or polymeric moldings. Such manufacturing methods are the

One skilled in the art and may include, for example, laser ablation or microetching. Since such microchannels correspond in terms of geometry and effect as a restrictor to the pipeline-based capillary restrictors, such microchannels are also regarded as "capillary restrictors" for the purposes of the present invention.

In a preferred embodiment, capillary restrictors used are glass capillary restrictors, ceramic capillary restrictors or stainless steel capillary restrictors, the use of glass capillary restrictors or ceramic capillary restrictors being preferred.

Particular preference is given to capillary restrictors which consist of an "elastic" ceramic material, that is to say a ceramic material with a modulus of elasticity ("Young's Modulus") of less than 90 GPa, preferably less than 70 GPa. These capillary restrictors preferably consist of "drawn" glass and in particular preferably of "fused silica" or "fused quartz" or mixtures of these and other ceramic materials. Such ceramic capillary restrictors are actually known in another technical field, namely the field of chromatography as support materials for gas chromatographic separation columns. Due to the high commercial relevance of chromatographic methods, these capillary restrictors are well developed and cost-effectively available on the market. It has now been shown that these actually come from another application ceramic capillary restrictors just Also suitable for use in test stands for high-throughput testing of catalysts.

Such restrictors, in particular fused silica capillary restrictors, can also be wound up well on rolls or turned into spirals ("wound

Wrapped capillaries are described by the column length, the number of turns per unit length and the mean diameter of a turn.

Preferably, the turns have an average diameter in the range of 5 cm to

30 cm up. Wound or twisted capillary restrictors can be heated particularly effectively and in a space-saving manner by the heating effect of adjacent windings.

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

In a preferred embodiment, the means for heating and / or cooling and the temperature sensors of at least two or more capillary restrictors are each connected to the same control device, it being preferred that the means for heating and / or cooling and temperature sensors for each at least four capillary restrictors each having the same temperature control or control device are connected. In particular, it is preferred that the means for heating and / or cooling and temperature sensors of at least eight capillary restrictors are each connected to the same temperature control or control device.

For heating and / or cooling the capillary restrictors, means for heating and / or cooling are preferably used for the purposes of the present invention, wherein the means for heating preferably comprise heating foils, heating plugs, heating cords, heating tapes or heating casings. Heating tapes or heating cords may, for example, enclose capillary restrictors or be turned into a coil together with the capillary restrictors. It is also preferred that a capillary restrictor is first turned into a coil independently of the means for heating and subsequently encased by the heating element. Means for cooling are preferably realized via a heat exchanger, for example a fluid cooling.

For the purposes of the present invention, a means for heating is to be regarded as a "means for changing the temperature", and therefore also includes a means for cooling or for heating and for cooling.

In the event that metal capillary restrictors are used as restrictors, they are preferably flowed through directly by electric current, so that the

Capillary restrictors can act as a means of heating itself. Furthermore, it is preferable to position the capillary restrictors in a metal jacket tube and connect this jacket tube - analogous to the aforementioned metal capillary restrictors - directly to a power source and to use as a means for heating. Inside the heating jacket tube, capillary restrictors should preferably be made of electrically insulating materials.

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

If the capillary restrictors, whose outer surface is traversed by the electric current, are rolled together to form windings, the individual windings are preferably electrically insulated both side by side and in layers, so that no unheated loops can be formed by electrical bridging. Preferably, a coating of a heat-resistant lacquer is used for electrical insulation.

In a preferred embodiment, the capillary restrictor or the metal tube enclosing the capillary restrictor is used both as a means for heating and as a temperature sensor, with the proviso that the metal has a temperature-dependent resistance. For the purposes of the present invention, it is also preferable to heat or cool the capillary restrictors indirectly via heat exchangers, for example flowing around with a fluid. Heating via thermal radiation is also preferred.

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

The temperature of the individual capillary restrictors can preferably be varied within a range from room temperature to 350 ^° C. If the Kapillarrestriktor consists of a heat-resistant material, eg. Stainless steel, the Kapillarrestriktor can also be operated at temperatures above 350 ^0C. Capillary restrictors are preferably also cooled.

According to a preferred embodiment, the reaction products flowing out of the reaction vessels and / or (unreacted) starting materials are analyzed in at least one analyzer (eg a hot gas flow analyzer). It is preferred that the outflows of the individual reaction vessels, and thereby the outflows of individual reaction vessels, each can be analyzed separately, for example by using at least one selection valve, which the outflow of each reaction vessel to at least one Detector can switch, while the outflow of the other reaction vessels is not analyzed or otherwise analyzed. The use of 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 Capacitance Detector, ECD (Electron Capture Detector for High Electronegative Group Components), PID (Photoionization Detector), PED (Photoemission Detector). The analyzer is preferably connected to a process controller, wherein in a preferred embodiment it is possible to adjust the flow resistance of individual capillary restrictors by calibrating the analyzer's signal from the process controller to control at least one means for heating and / or cooling is used to adjust by settings of a predetermined Heizbzw. Cooling power desired flow amounts of fluid flow, which flows through the capillary restrictors to control or regulate.

The adjustment of the flow rate per restrictor is preferably carried out via a feedback circuit with the analyzer, more preferably before the actual catalytic examination is started. In a preferred embodiment, a gaseous substance (a so-called "tracer component") unaffected by the reaction, to which the analyzer reacts selectively, can serve as a reference fluid for adjusting the flow resistance by temperature regulation.

Overall, the means for heating / heating or the means for heating / cooling at least to some extent allows the active setting and / or calibration of a basically "passive" Restriktorelementes, in particular a Kapillarrestriktors.

In a further preferred embodiment, the present invention relates to a capillary reactor module (07) and 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.

Capillary restrictors are often delicate components that are subject to heavy stress due to extreme chemical and thermal conditions and high pressures, and thus may be susceptible to wear and aging. The term "extreme" chemical conditions implies that the capillary restrictors are reactive chemical substances may be exposed, which cause a change in the surface structure or can lead to a blocking of the restrictor 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 should be borne in mind that, in particular, the

Ends of the fused silica capillary restrictors (which preferably by means of

Graphite seals sealed and to metal fittings of pipelines or

Valves are attached) 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 defect sites are often difficult to find and a complex troubleshooting can cause delays in the

Commissioning of the entire test stand. Such defects, if unnoticed, can also jeopardize the data quality of the measurements.

The capillary restrictors are provided in capillary restrictor modules according to a preferred embodiment of the present invention, which are compact frames having two or more capillary restrictor elements and which comprise at least one heating and / or cooling means and at least one temperature probe per module. In each Kapillarrestriktormodul each individual Restriktorelement is preferably equipped with its own means for heating and / or cooling and / or its own temperature sensor. According to an alternative embodiment, all capillary restrictors of a module with a means common to all these capillary restrictors for heating and / or cooling are in thermal or physical contact.

The advantage of the capillary restrictor module is that it is a compact and robust component that is easy to handle, as it can preferably be mounted in the catalytic converter by means of metal or quick connect couplings in a time-saving and trouble-free manner.

The testing and testing of the capillary reactor module on its functionality and the determination of its technical properties can be carried out before its installation in the catalytic converter with the aid of a separate test stand, see above that the time for the construction or maintenance of the catalytic converter can be considerably shortened. This separate test rig is simpler in construction, so that the measuring time on the catalytic converter itself can be minimized for the testing of capillary restrictors.

In a preferred embodiment, two or more capillary restrictors are combined to form a module (07), preferably four or more capillary restrictors. According to a preferred embodiment, the frame (600) or the housing of the module comprises a good heat-conducting material, so that over the block also a temperature control 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.

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

An even number of threaded holes are preferably introduced in the planes of the smaller surfaces ("upper or lower surface") .The bores serve to receive a respective screwdriver (605, 605 '), preferably two of the threaded bores with one side open With the screwdriver, the fluidic connection of the module takes place on the one side, and the capillary restrictor (s) are sealed with the side turned into the thread of the metal block, so that the (optionally filigree) capillary restrictor module is no longer required. Capillary restrictors themselves, but rather only the screwdrivers are sealed. If gaps should occur in the grooves between two adjacent capillary restrictors, it is preferable to fill them by means of a compound (for example silicone) in order to ensure direct, thermally conductive contact with the capillary restrictors.

In a preferred embodiment, in each case at least one screwdriver comprises regularly divided and at least triangularly arranged surfaces between the two threads, wherein the surfaces are preferably quadrangular and more preferably hexagonal (see FIG. 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 used for mounting with a wrench and after completion of the recording as anti-rotation (see (604) in Figure 4).

If, for manufacturing reasons, it should be necessary to guide the groove into the bottom of the bore, it is further preferred to place a pressure distribution disc (602, 602 ') on the base of the threaded bore. The fluidic sealing of a capillary restrictor at the bottom of the bore preferably occurs via sealing cones (603, 603 ') made of graphite or another sealing material which the person skilled in the art typically uses 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 drivers (605) have been tightened with the torque required to compress the sealing cones, they are secured against further rotation and thus against excessive tightening or against loosening during the assembly of the fluidic inlets and outlets by applying an anti-rotation device (604).

With respect to the leads and leads leading to the module and away from the module, in a preferred embodiment they are provided with quick couplings.

Catalyst tests in which the Kapillarrestriktoren invention and Kapillarrestriktormodule be used are preferably laboratory tests, with which in usually between 0.1 g and 50 g of catalyst are tested. It is preferred to use the capillary restrictors of the invention in conjunction with catalysis tests 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 are in principle suitable for catalytic tests in which - in relation to the laboratory scale - relatively large amounts of catalyst are tested.

A problem frequently encountered in practice in the use of capillary restrictors relates to the fact that the channels of the capillary restrictors may possibly be easily blocked without this being directly noticeable. This leads to a greater variation or systematic shifts in the measurement data quality. The modularization and the heatability of the capillary restrictors according to the present invention helps to better characterize and monitor their properties so that an improved intervention in the occurrence of errors is possible.

A further advantage of the use of capillary restrictors over the use of active mass flow controllers in test stands is that the capillary restrictors in the construction according to the invention can be operated at higher temperatures and pressures than is the case with active mass flow controllers. It is thus possible to control the catalytic test stands under operating conditions that are technically otherwise difficult to implement.

In a further preferred embodiment of the present invention, the mechanical bending of capillary restrictors is another parameter by means of which the flow through the capillary restrictors can be controlled in addition to the thermal control or alternatively to the thermal control in a certain range. The bending consists either in the reversible shape change from a stretched to a wound capillary restrictor or the change in the winding number or the winding diameter. Such "bending" is preferably used in conjunction with "elastic" capillary restrictors (Young's modulus below 90 GPa or 70 GPa), in particular with "fused silica" capillaries. A preferred arrangement for heating a capillary restrictor using the capillary restrictor as a temperature sensor consists of the following components, which are also shown in the EMSR scheme in Figure 7: heating element (300) (with integrated capillary) with terminals (301, 304), take-off points (302 , 303), reference point (305) of a subtractor (306), an S & H stage (307) (S & H stage), a P [ID] controller (308), an inhibit stage (310), an actuator (311), a power supply for the heating element (312), a constant current source (315), a freewheel device for the constant current source (314) and a higher-level timer (309).

A constant current source (315) provides a current that is passed through the heating element (300). The feeding of the constant current is carried out as far as possible from the ends of the heating element. For feeding in, the earth-side (301) and the voltage-side (304) feed-in point are used. The voltage required for heating is supplied via the same feed-in points. Due to the electrical resistance of the heating element is formed via the heating element between the feed points, a voltage drop, which runs directly proportional to the resistance of the heating element according to the Ohm's law. The acceptance points (302 and 303) for this voltage are applied as close as possible to the feed points for the constant current (IT), by means of which the resistance is measured. This arrangement of the feed points results in the largest removable voltage and thus the largest measurement accuracy or measurement sensitivity.

Since this voltage represents the temperature, this is referred to below as the temperature voltage (UT). The acceptance points for UT (302 and 303) are associated with a subtracting stage (306). In this stage, the difference between the two acceptance points of UT is formed. As a result, disturbing influences, such as the electromotive force EMF suppressed from thermal stresses. The thus corrected signal is temporarily stored in the S & H stage (307). The task of the S & H stage (307) is to store the voltage representing the temperature during the time in which the heating voltage is applied. The S & H stage is connected to the actual value input of an at least Pl controller, preferably a PID controller (308). The control value output of the PID controller communicates with an inhibit stage (310), which signals the forwarding of the output signal the actuator (311) can completely suppress. In the activated state of the inhibit stage, the setpoint output can communicate directly with the actuator (312).

When the actuator (312) is deactivated by the inhibit stage (310), current flow through the actuator is suppressed to a technically feasible level. Preferably, the leakage current supplied by the actuator is less than at least 1/1000 of the constant current IT. The control input of the actuator is in communication with the inhibit stage. The actuator is on the input side with the Heizspannungsquelle (312) and the output side with the tube acting as a heating element (300) in combination.

The processing of UT in the described components can be realized both analogously as individual circuits and also digitally in a microprocessor system. The representation of the realization of the process in a digital microprocessor can be seen in FIG.

For the heating of the capillary restrictors a heat output of 1 to 50 W * m ^{"1 is} applied The constant current through the capillary restrictors should be on the order of 1/100 of the impressed heat output For a tube of stainless steel 316L with the dimensions 1/16 x 0.012 in (outer diameter x wall thickness) results in a heating voltage of 5.3 volts per meter and a heating current of 10 amps regardless of the length Constant current of 0.1 ampere.

The effective currents and voltages for heating as well as for the temperature measurement depend on the material and the electrically conductive cross-section of the capillary restrictor.

Another aspect pertaining to the invention or an aspect directly related to the invention is a calibration device, wherein in a preferred embodiment the device is in an oven.

The operation of the heating control cycle for the inventively heated Kapillarrestriktoren can be exemplified as follows: The subtractor is permanently fed the signal of the terminals UT. Thus, the temperature signal is available at the output of the subtracting during the time in which the actuator is disabled via the Inhibitstufe. While the actuator closes the heating circuit, a significantly larger current flows through the heating element, so that also at the terminals UT a significantly larger voltage is applied. However, since this significantly larger voltage has no significance for the temperature measurement, this period is advantageously hidden. The blanking takes place in the S & H stage, which is controlled via the higher-level timer (see FIG. 7).

Overall, a distinction can advantageously be made between the following four cycles: i) A measuring cycle in which the heating element acts as a temperature sensor. ii) A latency of the S & H stage, which proceeds to signal processing to a stable output signal. iii) A heating cycle in which the heating element is supplied with energy, it is thus below the heating voltage. iv) Measure a latency period in which the actuator is locked and the temperature sensing circuitry is tuned.

A higher-level timer synchronizes the sequence of the o.g. Operations.

The timer activates the S & H stage and at the same time blocks the inhibit stage. This ensures that the heating element is only flowed through by the constant current of the constant current source. The voltage value applied after all transient effects of the electronics is stored in the S & H stage at the moment of their deactivation. Thus, at the S & H stage, after their deactivation, the stored signal is available regardless of any changes in the input signal.

After a latency period dictated by the processing time of the S & H stage, the actuator is activated via the inhibit stage and a heating cycle is performed. After the lapse of the heating cycle time, after the latency time for the constant current source and the subtraction stage has lapsed, the S & H stage is activated and a new measurement cycle is thus carried out. The time for the complete cycle of a cycle should be short compared to the thermal inertia of the heating element. The thermal inertia of the heating element tT is given by the time in which the temperature in K decreases by 3% from the current value. In short, this means that the cycle tZ in tT is traversed at least ten times. It therefore applies tT <10 * tZ.

Method for calibrating the system for the purpose of setting temperatures

Since the restrictors are usually located in a surrounding oven, which itself has a temperature control device, this oven can be used in addition to control device for calibrating the device. Prerequisite for the procedure is that the surrounding furnace is able to produce the desired temperatures. Furthermore, it must be justified to assume that the capillary restrictors respectively tubes are at the same temperature as set on the regulator of the furnace. It must therefore be prevented, for example, that the Kapillarrestriktoren or pipes on any suspension points significantly heat is removed, or that the furnace heats unevenly. If the heater is not automatically located in a surrounding oven, it must be placed in an oven for calibration. It should be noted that the conditions are observed with respect to the mentioned uniform heating.

The furnace control is set one after the other in the temperature range to be controlled later. After each new setting of a temperature is waited until a temperature equilibration has taken place. If the temperature compensation has taken place, the temperature voltage UT is measured by means of the processing system and the corresponding voltage value is stored in a memory; the same applies to the temperature value. After passing through a cycle of several different temperatures, at least two different temperatures, and preferably more than two, results in a collection of values by means of which the voltage values can be retrieved for later temperature determination. In a preferred implementation of the method according to the invention, the furnace is first set to the temperature in which the calibration is to be performed. This range is between 20 ⁰ C and 500 ⁰ C, preferably between 50 ° C and 300 ⁰ C and in particular between 5O ⁰ C and 200 ⁰ C. It is assumed that the temperature distribution of the furnace used is present, so that the temperature of calibrating Kapillarrestriktor or serving as a heater tube with an accuracy of +/- 0.5 K can be predicted. The temperature value serves as a reference value for temperature calibration. The temperature voltage is measured after the equilibration time has elapsed. The temperature voltage is assigned to a temperature in a memory.

According to a further embodiment of the present invention, the test stand comprises at least two subgroups of reaction vessels arranged in parallel, each subgroup comprising at least two, more preferably at least three, more preferably at least four, parallel arranged reaction vessels. In this case, each reaction vessel of the at least two subgroups comprises at least one supply line and at least one discharge line. In this case, all reaction vessels of the at least two subgroups are connected to at least one fluid supply common to all reaction vessels. The feed lines to each reaction vessel each comprise at least one restrictor which preferably has the same flow resistance within each subgroup, it being preferred that the flow resistance between the restrictors of the subgroups be different.

At least one restrictor is preferably present in at least one subgroup, preferably all restrictors in this subgroup are in thermal and / or physical contact with at least one heating and / or cooling means which can heat (restrict) the restrictor to a different temperature, as the temperature of the environment and as the temperature of the respective reaction vessel. Preferably, the restrictors are capillary restrictors.

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

The use of restrictors with different flow resistances in at least two subgroups offers the advantage that with respect to the test rig a larger regime at different flow rates or GHSV conditions (namely at least two) can be adjusted, despite this variability in the flow through the reaction vessels one and the same fluid supply can be used.

This can be illustrated particularly clearly for a capillary flowed through as a restrictor (capillary restrictor). The flow resistance, which opposes such a restrictor fluid, according to the Hagen Poisenille law for laminar pipe flow from the viscosity of the fluid flowing through, namely in the sense of "flow resistance = viscosity x pipe length x 1 / pipe diameter to the fourth power". Thus, therefore, the flow resistance between the restrictors of two sub-groups can be adjusted differently by different length and / or tube diameter in a simple manner.

According to a preferred embodiment, for a subgroup of restrictors there is at least one means for heating (and / or cooling) which is in thermal and / or physical contact with at least one restrictor. Preferably, there is at least one heating / cooling means per subgroup, at least one means for heating being independent of at least one other means for heating, i. in particular adjustable to a different temperature. In this embodiment, it is possible to regulate restrictors by different temperature to different flow resistance and thus flows.

According to a preferred embodiment, old restrictors each comprise a means for heating, which are each independently controllable and / or controllable. This embodiment makes it possible to set each of the restrictors to a different flow resistance and thus to regulate the flows through the restrictors individually. The particular advantage of being able to heat and / or cool a restrictor in a controlled manner and separately from the other components of the test stand, in particular restrictors of a subgroup, is that the flow through the restrictors without movable mechanical components, such as those in valves, for example or flow regulators can be easily controlled, namely, that the temperature dependence of the viscosity of fluids is utilized.

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

In principle, this embodiment requires only one means for heating and / or cooling per subgroup of restrictors (and correspondingly only one control / control circuit), so it is particularly easy to set up and to handle. Despite this comparatively simple construction, in the two subgroups, by heating or cooling 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 are set by the reaction vessels, and in each case the same educt flow (since all supply lines are in communication with a common fluid supply).

According to another alternative embodiment, all of the restrictors of at least one of the at least two subgroups are not in thermal and / or physical contact with a heating and / or cooling means which could heat (cool) the restrictors to a different temperature than the temperature the surroundings and as the temperature of the respective reaction vessel, whereas all restrictors of the at least one other subgroup are in thermal and / or physical contact with a means for heating and / or cooling common to these restrictors. In a preferred embodiment, the restrictors within each of the at least two subgroups at 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 to at least 10% different, preferably by at least 20%, more preferably by at least 50%.

In the context of the present embodiment, it is preferred, as described above, for a catalytic test stand to comprise at least two subgroups of two, four, eight or more reaction vessels, that is to say a total of a large number of capillary restrictors. It will also be appreciated that improved and easy handling of the capillary restrictors is of great economic interest. For example, a test rig having sixteen reactors in parallel may be equipped with 16 to 64 capillary restrictor elements (since capillary restrictors are not only used for reaction chamber inlet side fluid control as described above, but also reaction exit side for pressure reduction or uniform distribution of holding gas in many applications ), which then twice as many Kapillarrestriktorendstücke and thus twice as many joints, ie 32 to 128 connection points, between capillary lines and connecting cables has.

According to an alternative embodiment, per capillary restrictor module two or more capillary restrictors each comprise a means for heating and / or cooling or all capillary restrictors a common means for heating and / or cooling.

One embodiment comprises a test rig for parallel testing of catalysts under different flow conditions, wherein the test rig comprises at least two subgroups of reaction vessels arranged in parallel, each subgroup comprising at least two or three or four reaction vessels arranged in parallel and each reaction vessel of the at least two subgroups comprising at least one Supply line and at least one derivative includes and all Reaction vessels of the at least two subgroups are connected to at least one reaction vessel common fluid supply, wherein the supply lines to each reaction vessel each comprise at least one restrictor, characterized in that the restrictors have the same flow resistance under the same other conditions within a subgroup, but between at least two subgroups have a different flow resistance.

It is preferred that the restrictors are capillary restrictors.

It is preferred that in at least one subgroup at least one restrictor is in thermal and / or physical contact with at least one means for heating and / or cooling, which can respectively heat or cool the restrictor to a different temperature than the temperature of the environment and as the temperature of the respective reaction vessel.

It is preferred that there are at least two means for heating and / or cooling, which are each in thermal and / or physical contact with at least one restrictor.

It is preferred that at least one means for heating be independent of the at least one other means for heating and / or cooling, i. is adjustable to a different temperature.

It is preferred that each subgroup comprises at least four or at least six reaction vessels and at least four or at least six restrictors.

It is preferred that all restrictors of at least one subgroup each comprise a heating means common to all these restrictors.

It is preferred that the flow resistance of the restrictors of the one subgroup is different from the flow resistance of the at least one other subgroup by at least 10%, preferably by at least 20%, more preferably by at least 50%. It is preferred that the restrictors are capillary restrictors having a characteristic length which is at least five hundred times greater than the characteristic mean diameter.

The internal diameter of the capillary restrictors is preferably less than or equal to 250 μm and preferably the length of the capillary restrictors ranges from 1 m to 6 m.

It is preferred that the Kapillarrestriktoren consist of 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 consist of fused silica or fused quartz.

It is preferred that at least one means for heating and / or cooling and / or at least one restrictor comprises at least one temperature sensor.

It is preferred that the reaction products flowing out of the reaction vessels and / or unreacted educts and / or specially added "tracer" fluids are analyzed in at least one analyzer and the control and / or regulation of the test stand is suitable for the flow resistance of individual capillary restrictors by adjusting or calibrating the signal of an analyzer by the controller and / or controller for controlling or controlling at least one means for heating and / or cooling, by setting a predetermined or calculated heating or Cooling power predetermined flow amounts of fluid flow passing through the Kapillarrestriktoren to control or regulate.

Embodiment 1

In a series of tests, capillary restrictors each equipped with a heating element and a temperature sensor were installed in a test stand. The capillary restrictors used in this case are fused silica capillary restrictors with an internal diameter of 75 μm and a length of 2 m.

The capillary restrictors used in the experimental apparatus were connected to a compressed gas line, via a pressure regulator a desired Pressure difference along the individual capillary restrictors from the input side to the output side has been set. In the present example, nitrogen was used as the compressed gas and a pressure difference of 20 bar was set. The temperature of the capillary restrictors was increased from 11O ⁰ C to 190 ⁰ C, wherein in each case in temperature stages of 20 K, a determination of the flow rate was made. The flow rates are summarized in the table. By increasing the temperature by only 70 K, the flow can thus be reduced by about 30% by an otherwise unchanged capillary restrictor, ie set quasi active. In contrast to an active restrictor, for example, a flow controller with Nadeliochengstelle, but this no mechanically moving parts are necessary.

Table 1

Embodiment 2 In another series of tests, capillary restrictors were just installed in a test rig and the flow characteristics of gases in relation to the winding parameters were investigated. The results of the study are shown in Table 2. The capillary restrictors used in this case are fused silica capillary restrictors with an internal diameter of 75 μm and a length of 1.5 m.

The capillary restrictors used in the experimental apparatus were connected to a compressed gas line, wherein a desired pressure difference along the individual Kapillarrestriktoren was adjusted from the input side to the output side via a pressure regulator. In the present examples, nitrogen and helium were used as the pressurized gas and various pressure differences were set. The capillary restrictors were tested at 25 ° C. Subsequently, the capillaries were wound up differently and also tested at different pressures.

Table 2 lists the various winding parameters, number of windings, winding radius and winding length and the fluxes measured at different pressure differences, using nitrogen as the gas. The in the table 2 made pressure refers to the overpressure. The difference between the wound length and the total length of the capillary gives the length of the unwound capillary part.

The corresponding table for helium as fluid is Table 3:

For a given pressure difference, a loss (relative loss of flow rate) is calculated by comparing the measurements of un-wound capillary with those of the wound capillary. This is a maximum of 18.4%.

In addition, the change was calculated. This was calculated from the amount of flow for the unwound capillary in relation to the flow rate of the almost completely wound capillary with 7 turns of 6 cm diameter and amounts to a maximum of 22.5%.

From the measurements, it can be deduced that the flux decreases with the length of the windings and the winding diameter at a given pressure difference. In addition, it can be seen that the change increases as the Reynolds number increases, reaches a maximum at 1600, and decreases again.

List of Reference Numerals 2 ... 06 - controllable or controllable capillary restrictors - capillary restrictor module - means for heating - capillary line - multi-port valve - analyzer - outlet line to the exhaust air - analyzer-side exhaust air line, including a

Connection to the line (54) may be present - electronic connection line to the controller or control program of the apparatus - controller or control unit for controlling or controlling the heatable capillary restrictors - 110 - Reaction vessels - 210 - connecting lines between the controllable or controllable capillary restrictors and the reaction vessels - 229 - controllable or controllable capillary restrictors - heating element, 304 - connections, 303 - acceptance points - reference points for circuits (316) and (312) - subtraction stage - S & H stage (Sample & Hold stage is the same as sample memory,

Capacitor of the voltage stores) '- digital processing according to (307) - PID controller "- software PID controller - higher-level timer for controlling the measuring cycle compared to the heating cycle - inhibit stage - actuator 313 Constant current feed

314 freewheel device for constant current

315 constant current source

316 Voltage supply of the constant current source for resistance measurement

317 Actual value for (320)

318 external setpoint input for (308) (internal PID controller)

319 Setpoint input for cascade controller

320 superordinate cascade controller

350 matching amplifier (conditioning amplifier or attenuator) for (303)

351 lowpass in the channel (303)

352 matching amplifier (conditioning amplifier) for (302)

353 lowpass for channel (302)

356 analog-to-digital converter in the channel (303)

357 analog-to-digital converter in the channel (302)

360 function group that can be displayed by MikroController

362 Timing Synchronization Bus

363 Timer for the sequence control

401 - 410 supply lines to the controllable or adjustable capillary restrictors

501 - 510 Connecting cables of the temperature sensors to a controller or control box

600 Housing (frame) with recess for capillary restrictors and threaded receiving areas

601, 601 'grooves or recesses

602, 602 'insert elements (for example washers)

603, 603 'Sealing element with passage for capillary restrictor

604, 604 "retaining bar (anti-twist protection)

605, 605 'two-sided screw thread (can at least be provided on one side with quick coupling or bayonet closure)

606, 606 'Sealing element with bushing for cable

607, 607 'screw connection with bushing (union nut) 608, 608 ', 609 "- corresponds to (605) (here with δeckiger mother and 12eckiger

Screw)

701 - 710 - Supply lines for operating the means of heating, which are in communication with the capillary restrictors

801 - 810 - Input positions for the temperature sensors on the controller or control box

901 - 910 - Starting positions from the controller to the heating elements of the

Kapillarrestriktoren

Claims

claims

1. test stand comprising at least two reaction vessels arranged in parallel, wherein each reaction vessel comprises at least one supply line and at least one derivative and all reaction vessels of the test stand 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 at least one of the at least two restrictors is in thermal and / or physical contact with at least one means for heating and / or cooling which can respectively heat or cool the restrictor to a different temperature than the ambient temperature and the temperature of the respective reaction vessel.

2. Test stand according to claim 1, characterized in that in the test stand at least four or at least six parallel arranged reaction vessels and thus also at least four or at least six leads and at least four or at least six restrictors are present.

3. Test stand according to one of claims 1 or 2, characterized in that the flow resistance in the restrictors of the supply lines are the same or substantially the same under otherwise identical conditions.

4. Test stand according to at least one of the preceding claims, characterized in that the restrictors are capillary restrictors.

5. test stand according to at least one of the preceding claims, characterized in that the test stand at least two means for heating and / or Includes cooling, which are each in thermal and / or physical contact with at least one restrictor.

6. A test stand according to claim 5, characterized in that at least one means for heating and / or cooling is independent of the at least one other means for heating and / or cooling, i. is adjustable to a different temperature.

7. Test stand according to claim 5, characterized in that all restrictors of the test stand are in each case with at least one means for heating and / or cooling in thermal and / or physical contact, wherein all means for heating and / or cooling independently and / or or are controllable.

8. Test stand according to claim 1, characterized in that all restrictors with a single means for heating and / or cooling are in thermal and / or physical contact.

9. Test stand according to at least one of the preceding claims, characterized in that the restrictors are capillary restrictors, which have a characteristic length which is at least five hundred times greater than their characteristic mean diameter.

10. Test stand according to claim 9, characterized in that the inner diameter of the Kapillarrestriktoren is less than or equal to 250 microns and the length of Kapillarrestriktoren from 1 m to 6 m.

11. A test stand according to at least one of claims 4 to 10, characterized in that the Kapillarrestriktoren made of a ceramic material with a modulus of elasticity or Young's modulus less than 90 GPa, preferably less than 70 GPa, and preferably consist of drawn glass, and thereby further preferably consist of fused silica or fused quartz.

12. 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.

13. Test stand according to at least one of the preceding claims, characterized in that the effluent from the reaction vessels reaction products and / or unreacted educts and / or specifically added to the control and / or regulation tracer fluid is analyzed in at least one analyzer or be and Control and / or regulation of the test stand is adapted to adjust the flow resistance of individual Kapillarrestriktoren characterized calibrate or regulate that the signal of an analyzer of the control and / or regulation for controlling or controlling at least one means for heating and / or cooling is used to control predetermined flow rates of fluid flow passing through the capillary restrictors by adjusting a predetermined heating or cooling power.

14. Test stand according to one of the preceding claims, characterized in that 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 includes a derivative and all the reaction vessels of at least two

Subgroups with at least one reaction vessel common to all fluid supply are connected, wherein the supply lines for each reaction vessel in each case comprise at least one restrictor, characterized in that the restrictors have the same flow resistance under the same other conditions within a subgroup, but have a different flow resistance between at least two subgroups ,