High-temperature measuring device and electrochemical system

Abstract

The invention is based on a high-temperature measuring device (10a; 10b; 10c) for analyzing a composition of a process fluid of a chemical, in particular electrochemical, conversion, with at least one sensor unit (12a; 12b; 12c), wherein the sensor unit (12a; 12b; 12c) comprises at least one Nernst cell, in particular in the form of a lambda probe (14a, 16a, 18a, 20a; 14b, 16b, 18b, 20b), for analyzing the process fluid. It is proposed that the high-temperature measuring device (10a; 10b; 10b) comprises a measuring chamber (22a; 22b; 22c) for receiving the process fluid, wherein the sensor unit (12a; 12b; 12c) is arranged at least partially in the measuring chamber (22a; 22b; 22c).

Description

Prior ArtA high-temperature measuring device for analyzing a composition of a process fluid of a chemical, in particular electrochemical, conversion, having at least one sensor unit, wherein the sensor unit comprises at least one Nernst cell, in particular in the form of a lambda probe, for analyzing the process fluid, has already been proposed.Disclosure of the InventionThe invention is based on a high-temperature measuring device for analyzing a composition of a process fluid of a chemical, in particular electrochemical, conversion, having at least one sensor unit, wherein the sensor unit comprises at least one Nernst cell, in particular in the form of a lambda probe, for analyzing the fluid.It is proposed that the high-temperature measuring device comprises a measuring chamber for receiving the process fluid, wherein the sensor unit is arranged at least partially in the measuring chamber. The high-temperature measuring device is preferably designed for a temperature of the process fluid of more than 250° C., preferably of more than 400° C., particularly preferably of more than 500° C. The high-temperature measuring device is preferably designed for a temperature of the process fluid of at least up to 600° C., preferably at least up to 700° C. The sensor unit is preferably provided to detect a portion of at least one component of the process fluid. The measuring chamber is preferably provided to receive the process fluid in a gaseous state. In the chemical conversion, a fuel is preferably converted into an exhaust gas, for example, by a fuel cell, by a burner, by an internal combustion engine or the like. The high-temperature measuring device can be provided for analyzing the fuel and / or the exhaust gas as process fluid. The sensor unit is preferably provided to detect a proportion of at least one oxidizable component, for example carbon monoxide, hydrogen, methane or the like, in the process fluid. The high-temperature measuring device is provided in particular to monitor that the lower explosion limit (UEG) of the at least one oxidisable component is not exceeded in the exhaust gas.The measuring chamber preferably has a base, a central wall and a cover along a main direction of extension of the measuring chamber. A "main extension direction" of an object is to be understood here in particular as a direction which runs parallel to a longest edge of a smallest geometric cuboid which just still completely encloses the object. The terms bottom and cover serve here merely to distinguish between the components and the main direction of extent of the measuring chamber can assume any desired orientation, in particular an application-dependent orientation, in space. The central wall preferably delimits a receiving volume of the measuring chamber in a cross-sectional plane perpendicular to the main direction of extension. The central wall preferably has in the cross-sectional plane an annular, alternatively an oval-ring-shaped or polygonal-ring-shaped, in particular rectangular, profile. Preferably, a maximum transverse extension of the receiving volume of the measuring chamber, which is predetermined by the central wall, is constant along the main extension direction of the measuring chamber. Alternatively, the central wall is curved or is formed tapering or widening along the main direction of extension. The base and the cover preferably delimit the receiving volume of the measuring chamber in the main direction of extent. The base and the cover can be constructed identically or differently. Preferably, a respective main extension plane of the base and / or of the cover runs at least substantially perpendicular to the main extension direction of the measuring chamber. A "main extension plane" of a structural unit is to be understood in particular as a plane which is parallel to a largest side surface of a smallest imaginary cuboid which just still completely encloses the structural unit and in particular runs through the center point of the cuboid. The expression "substantially perpendicular" is intended here in particular to define an orientation of a direction relative to a reference direction, wherein the direction and the reference direction, in particular viewed in a projection plane, enclose an angle of 90° and the angle has a maximum deviation of in particular less than 8°, advantageously less than 5° and particularly advantageously less than 2°. The base and / or the cover are / are preferably designed as a, in particular planar, plate. Alternatively, the base and / or cover is / are funnel-shaped, arched, in particular configured as a hopper base or as a basket arch base, or the like. In an advantageously simple embodiment, the measuring chamber is formed cylindrically, wherein a cylinder axis defines the main extension direction of the measuring chamber.The sensor unit comprises at least one sensor, preferably a plurality of sensors, which / r is arranged at least partially in the measuring chamber. Preferably, at least one measuring point of the sensor is arranged within the measuring chamber. For example, a sensor-internal signal processing unit of the at least one sensor can be arranged outside the measuring chamber. The at least one sensor is preferably arranged on the central wall and projects in particular through the central wall into the measuring chamber. The at least one sensor preferably comprises the at least one Nernst cell. The at least one sensor is preferably designed as a lambda probe, in particular as a jump lambda probe or as a broad-band lambda probe. In an advantageously cost-effective embodiment, the at least one sensor is present as a prefabricated part which is connected to the measuring chamber. In an advantageously compact configuration, the at least one sensor and the measuring chamber are formed integrated into one another, for example by applying layers of the Nernst cell to the central wall. It is conceivable for the sensor unit to comprise further sensor elements which are arranged in or outside the measuring chamber and which are provided in particular for state detection of the process fluid and / or of the at least one sensor, for example for correction and / or classification of a measured value of the at least one sensor. Further sensor elements include, for example, a temperature sensor element, a pressure sensor element, a flow rate sensor element or the like."Provided" is to be understood in particular as being specially programmed, designed and / or equipped. The fact that an object is provided for a specific function is to be understood in particular to mean that the object fulfills and / or executes this specific function in at least one application state and / or operating state.By means of the configuration according to the invention, an advantageously defined and consistent flow of the process fluid at the sensor unit can be achieved. In particular, a flow behavior of the process fluid predefined by the measuring chamber can be specifically matched to a specific configuration of the sensor unit. For example, the measuring chamber can be optimized by means of numerical fluid mechanics (CFD) in order to set at least one flow parameter of the process fluid at the sensor unit, in particular a Reynolds number and / or a flow speed of the process fluid and in particular in order to align values of the flow parameter at different sensors of the sensor unit to each other.It is further proposed that the measuring chamber comprises a fluid inlet and a fluid outlet arranged at a distance from the fluid inlet. Preferably, the fluid inlet is disposed in the floor. Preferably, the fluid outlet is arranged in the cover. The high-temperature measuring device preferably comprises a fluid guiding unit for guiding the process fluid into the measuring chamber and out of the measuring chamber. The fluid guiding unit preferably comprises at least one supply line element which is connected to the fluid inlet. The fluid guidance unit preferably comprises at least one discharge line element, which is connected to the fluid outlet. Line elements of the fluid guidance unit can be designed, for example, as tubes, hoses, shafts or the like. The supply line element preferably protrudes through the fluid inlet into the measuring chamber. The discharge line element preferably protrudes through the fluid outlet into the measuring chamber. The supply line element and the discharge line element are arranged spaced apart from one another within the measuring chamber. Outside the measuring chamber, the supply line element and the discharge line element can be spaced apart from one another or arranged on one another. By means of the configuration according to the invention, an advantageously continuous operation of the high-temperature measuring device can be achieved. In particular, a change in the composition of the process fluid can be advantageously detected quickly.It is further proposed that the fluid inlet and the fluid outlet are arranged at mutually opposite ends of a maximum longitudinal extent of the measuring chamber. The measuring chamber preferably has the maximum longitudinal extent along the main direction of extent, in particular the cylinder axis. Preferably, the fluid inlet and the fluid outlet are arranged coaxially with respect to the main direction of extension, in particular the cylinder axis, of the measuring chamber. In particular, the fluid inlet and the fluid outlet are arranged along a principal axis of inertia of the measurement chamber. By means of the configuration according to the invention, an advantageously laminar flow of the process fluid can be achieved. In particular, a fluctuation range of measured values of the sensor unit due to turbulences of the process fluid can be advantageously kept small. Furthermore, an advantageously symmetrical flow profile of the process fluid within the measurement chamber can be achieved.It is further proposed that the high-temperature measuring device comprises at least one fluid sample for taking a measurement quantity of the process fluid from an external fluid line. The fluid sample is preferably connected to the supply line element. The fluid sample has, for example, the shape of a Pith tube. The fluid sample preferably comprises an L-shaped tube element, with a removal section and a discharge section running transversely thereto, in particular perpendicularly. The fluid sample is preferably provided to be introduced with the removal section first into the external fluid line counter to a provided flow direction of the process fluid within the external fluid line. The discharge section connects the removal section preferably fluidically to the supply line element. The supply line element and the fluid sample can be formed as separate components or in one piece with one another. Alternatively to a fluid sample, the supply line comprises a flange or the like with an inlet opening which is provided for connection to the external fluid line. By means of the configuration according to the invention, a pressure difference of the process fluid over the high-temperature measuring device can be advantageously kept high. In particular, a risk of a lack of flow through the measuring chamber can be advantageously kept low.It is further proposed that the sensor unit comprises at least two Nernst cells, wherein the Nernst cells are arranged in a plane which runs at least substantially perpendicular to a provided main flow direction of the process fluid through the measuring chamber. The provided main flow direction is preferably directed from the fluid inlet to the fluid outlet. Preferably, the main flow direction is preferably at least substantially parallel to the main extension direction, in particular the cylinder axis, of the measuring chamber. Here, "substantially parallel" is to be understood in particular as an alignment of a direction relative to a reference direction, in particular in a plane, wherein the direction has a deviation in particular of less than 8°, advantageously of less than 5° and particularly advantageously of less than 2° with respect to the reference direction. Preferably, the sensor unit comprises the already mentioned sensor with the already mentioned Nernst cell and at least one further sensor with at least one further Nernst cell. The sensor and the further sensor are preferably of identical construction. Alternatively, the sensor and the further sensor have different types of construction. The further sensor is preferably designed as a lambda probe, in particular as a jump lambda probe or as a broad-band lambda probe. The further sensor and the sensor are preferably arranged spaced apart from one another. The sensor and the further sensor are preferably arranged in the same plane, which runs at least substantially perpendicular to the provided main flow direction, in particular the main extension direction of the measuring chamber. Preferably, at least the measurement points of the sensors are arranged in the same plane, which runs at least substantially perpendicular to the provided main flow direction. In particular, a main extension direction of the sensor and / or a main extension direction of the further sensor are / is additionally arranged in the same plane. Alternatively, the main extension directions of the sensors are arranged inclined from the plane of the measuring point in the direction of the fluid outlet of the measuring chamber in order to prevent the penetration of condensate into the sensors. In particular, a fluid outlet-side angle between the provided main flow direction and the main extension directions of the sensors is equal to or smaller than the fluid inlet-side supplement angle thereto. The further sensor is provided, for example, to record a reference value for a measured value of the sensor. By virtue of the configuration according to the invention, differences in the flow parameters of the process fluid at the Nernst cells can advantageously be kept small, in particular negligibly small.It is further proposed that the sensor unit comprises at least four Nernst cells, wherein the Nernst cells are arranged in a plane which runs at least substantially perpendicular to a provided main flow direction of the process fluid through the measuring chamber. The sensor unit preferably comprises at least four sensors, in particular designed as lambda probes, each of which comprises at least one of the Nernst cells. The sensors are preferably arranged spaced apart from one another. The sensors are preferably arranged in the same plane which runs at least substantially perpendicular to the provided main flow direction, in particular the main extension direction of the measuring chamber. Preferably, at least the measurement points of the sensors are arranged in the same plane, which runs at least substantially perpendicular to the provided main flow direction. In particular, a main extension direction of the sensor and / or a main extension direction of the further sensor are / is additionally arranged in the same plane. Alternatively, the main extension directions of the sensors are arranged inclined from the plane of the measuring point in the direction of the fluid outlet of the measuring chamber in order to prevent the penetration of condensate into the sensors. In particular, a fluid outlet-side angle between the provided main flow direction and the main extension directions of the sensors is equal to or smaller than the fluid inlet-side supplement angle thereto. By virtue of the configuration according to the invention, differences in the flow parameters of the process fluid at the Nernst cells can advantageously be kept small, in particular negligibly small. Furthermore, a risk that the sensor unit will fail completely can advantageously be kept small. In particular, the high-temperature measuring device can advantageously continue to be operated in the event of a failure of one of the Nernst cells. Furthermore, by comparing, averaging and / or the like of measurement values of the Nernst cells, a risk that a measurement error will occur and / or not be recognized can advantageously be kept small.It is further proposed that the Nernst cells are arranged on the measuring chamber at least substantially rotationally symmetrically with respect to the provided main flow direction, in particular with respect to the main extension direction and / or the cylinder axis of the measuring chamber. Preferably, a periphery of the measuring chamber of the cross-sectional plane can be divided into, in particular four, segments of the same size, wherein one of the sensors with the Nernst cells is arranged in each segment. The sensors are preferably arranged in a star shape in the cross-sectional plane, wherein an intersection point of the main flow direction with the cross-sectional plane forms a center of gravity of the star-shaped arrangement. In particular, the arrangement of the sensors has a four-fold rotational symmetry. By virtue of the configuration according to the invention, differences in the flow parameters of the process fluid at the Nernst cells can advantageously be kept small, in particular negligibly small. In particular, differences due to a flow profile of the process fluid can be advantageously kept small. In particular, a different cooling effect of the flow on the sensors can advantageously be kept small, so that measurement values of the sensors are advantageously comparable to one another.It is further proposed that the high-temperature measuring device comprises at least one insulation housing which at least substantially completely surrounds the measuring chamber. The insulation housing is provided for thermally decoupling the measuring chamber and / or the sensor unit from the surroundings of the high-temperature measuring device. The measuring chamber is preferably arranged completely in an interior of the insulation housing, wherein the fluid guidance unit reaches through the insulation housing through at least one recess of the insulation housing in order to reach the measuring chamber. Alternatively, the bottom and / or cover of the measuring chamber is exposed. The exposed cover and / or base of the measuring chamber can protrude from the insulation housing, be arranged flush with the insulation housing or be formed integrally with the insulation housing. Preferably, the central wall is arranged in the interior of the insulation housing at a distance from an inner wall of the insulation housing. An intermediate space between the insulation housing and the measuring chamber is preferably filled with an insulating material. In particular, measurement values of the sensor unit recorded offset in time can advantageously be kept comparable. Furthermore, a temperature of the process fluid can advantageously be kept constant. In particular, a heat loss of the process fluid due to a flow through the high-temperature measuring device can be advantageously kept small.It is further proposed that the high-temperature measuring device comprises at least one fluid guide unit for guiding the process fluid to and / or from the measuring chamber, wherein the fluid guide unit forms at least one spacer, by means of which the insulation housing and the measuring chamber are arranged spaced apart from one another. Preferably, the insulation housing and the measuring chamber are fastened at a distance from one another on the supply line element and / or on the discharge line element. Preferably, the supply line element and / or the discharge line element is designed to absorb a weight force of the measuring chamber and in particular of the insulation housing. Alternatively or additionally, the insulation housing comprises support elements which are arranged on the central wall of the measuring chamber in order to secure a relative position of the measuring chamber to the insulation housing. Due to the configuration according to the invention, the measuring chamber can be advantageously effectively held by an environment of the high-temperature measuring device.Furthermore, an electrochemical system with at least one electrochemical cell and with at least one high-temperature measuring device according to the invention, which is fluidically connected to the electrochemical cell, is proposed. The at least one electrochemical cell is preferably provided for carrying out the chemical, in particular electrochemical, reaction. The at least one electrochemical cell is preferably designed as a high-temperature electrochemical cell, in particular as a solid oxide fuel cell, as a solid oxide electrolysis cell, as a molten carbonate fuel cell, as a molten carbonate electrolysis cell or the like. The at least one electrochemical cell has in particular an intended operating temperature of more than 200° C., preferably of more than 400° C., in particular of more than 600° C. The high-temperature measuring device can be connected to a reactant feed of the electrochemical system to the at least one electrochemical cell, to a product outlet of the at least one electrochemical cell, to a product return of the electrochemical system from the product outlet of the at least one electrochemical cell into the reactant feed of the electrochemical system or to a product outlet of an aftertreatment unit, in particular to an afterburner outlet, of the electrochemical system downstream of the at least one electrochemical cell. The chemical reaction by the electrochemical system can advantageously be monitored reliably and consistently by the configuration according to the invention.It is further proposed that the electrochemical system comprises a system fluid guidance unit for guiding the at least one process fluid from and / or to the at least one electrochemical cell, wherein the high-temperature measuring device is connected to the system fluid guidance unit in the form of a bypass. The system fluid guidance unit comprises, for example, the abovementioned reactant feed, a product discharge connected to the product outlet and / or the abovementioned product recirculation. Preferably, the discharge line element is connected to the system fluid guidance unit downstream of the supply line element. The high-temperature measuring device is preferably provided for the purpose of extracting only a part of the process fluid located in the system fluid guide unit, supplying it to the sensor unit and feeding it back into the system fluid guide unit. By means of the configuration according to the invention, an advantageously constant flow through the high-temperature measuring device can be achieved. In particular, a degree of turbulence formation due to a sensor projecting too far into the system fluid guidance unit can be advantageously avoided. Furthermore, a flow depletion zone on a sensor, which is arranged, for example, in a T-piece of the system fluid guidance unit, offset too far back can be advantageously avoided.The high-temperature measuring device according to the invention and / or the electrochemical system according to the invention should / should not be limited to the application and embodiment described above. In particular, the high-temperature measuring device according to the invention and / or the electrochemical system according to the invention can have a number which differs from a number of individual elements, components and units mentioned herein in order to fulfil a mode of operation described herein. In addition, in the value ranges specified in this disclosure, values lying within the stated limits should also be considered as disclosed and usable as desired.DRAWINGSFurther advantages are evident from the following description of the drawings. Three exemplary embodiments of the invention are shown in the drawings. The drawings, specification and claims contain numerous features in combination. The skilled person will expediently also consider the features individually and summarize them to form meaningful further combinations.The following are shown: FIG. 1 shows a schematic illustration of an electrochemical system according to the invention, FIG. 2 shows a schematic illustration of a high-temperature device according to the invention, FIG. 3 shows a schematic illustration of an alternative configuration of a high-temperature device according to the invention, and FIG. 4 shows a schematic illustration of an alternative configuration of an electrochemical system according to the invention.DESCRIPTION OF THE EMBODIMENTSFIG. 1 shows an electrochemical system 36 a. The electrochemical system 36 aincludes at least one electrochemical cell 38 afor electrochemical conversion. Preferably, the electrochemical system 36a includes a plurality of electrochemical cells 38a electrically connected in series for common operation. The electrochemical system 36 ais designed, for example, as a fuel cell system for electrochemical conversion of a fuel into an exhaust gas. The electrochemical system 36 apreferably comprises a system fluid guidance unit 40 afor supplying the fuel to the at least one electrochemical cell 38 aand for disposing of the exhaust gas. A feed branch of the system fluid guidance unit 40 aconnected to an inlet, in particular to an anode inlet, of the electrochemical cell 38 aincludes, for example, in particular in this order: a flow control element 41 a, for example a throttle or a blower, for adjusting a feed rate of fresh fuel, a recirculation feed unit 42 a, for example a fan, a blower or compressor, for adjusting a recirculation rate of the exhaust gas into the fuel, a recirculation recuperator 44 afor transferring heat from the recirculated exhaust gas to the fuel, a product-reactant heat exchanger 46 afor transferring heat from non-recirculated exhaust gas to the fuel and / or a reformer 48 afor reforming the fuel. A discharge branch 56 aof the system fluid guidance unit 40 aconnected to a product outlet 52 a, in particular to an anode inlet, of the electrochemical cell 38 acomprises, for example, an afterburner 50 afor burning fuel residues in the exhaust gas. An outlet of the afterburner 50a is preferably connected to the product-reactant heat exchanger 46a. A product return 54 aof the system fluid guidance unit 40 apreferably connects the product outlet 52 a, in particular the anode outlet, of the electrochemical cell 38 ato the supply branch of the system fluid guidance unit 40 a, preferably upstream of the reformer 48 a, in particular the recirculation feed unit 42 a, and downstream of the flow control element 41 a. The electrochemical system 36 apreferably comprises a further system fluid guidance unit 58 afor supplying the electrochemical cell 38 awith an oxygen-containing fluid, in particular air, in particular on the cathode side.The electrochemical system 36 apreferably comprises at least one high temperature measuring device 10 awhich is fluidically connected to the electrochemical cell 38 a. The high-temperature measuring device 10 ais here connected by way of example to the product outlet 52 aof the electrochemical cell 38 a. The high temperature measurement device 10 amay be connected upstream and / or downstream of a branch of the product return 54 ato the product outlet 52 a. Alternatively, the high-temperature measuring device 10 aor an additional high-temperature measuring device 10 ais arranged on the product return 54 aor in the feed branch, in particular downstream of the reformer 48 a. The high-temperature measuring device 10 ais provided for analyzing a composition of a process fluid of the electrochemical conversion, here of the exhaust gas, alternatively of the fuel and / or of a fuel-exhaust gas mixture. The high temperature measuring device 10 aincludes at least one sensor unit 12 a. The high-temperature measuring device 10 aincludes a measuring chamber 22 afor receiving the process fluid, wherein the sensor unit 12 ais at least partially arranged in the measuring chamber 22 a. The measurement chamber 22 ais connected to the system fluid guide unit 40 ain the form of a bypass.FIG. 2 shows the high temperature measurement device 10 a. The measuring chamber 22 ais preferably cylindrical. The measuring chamber 22 aincludes a fluid inlet 24 aand a fluid outlet 26 aarranged at a distance from the fluid inlet 24 a. The measuring chamber 22 ahas a main extension direction which preferably runs at least substantially parallel to a provided main flow direction 30 aof the process fluid, in particular of the exhaust gas, through the measuring chamber 22 a. The fluid inlet 24 aand the fluid outlet 26 aare arranged at mutually opposite ends of a maximum longitudinal extent of the measuring chamber 22 a. The maximum longitudinal extent runs parallel to the main direction of extent. The maximum longitudinal extent is preferably greater than, in particular at least twice as large as, a maximum transverse extent, in particular diameter, of the measuring chamber 22 aperpendicular to the maximum longitudinal extent.The sensor unit 12 apreferably comprises at least four lambda probes 14 a, 16 a, 18 a, 20 a, each of which comprises at least one Nernst cell. Lambda probes 14 a, 16 a, 18 a, 20 aare preferably formed separately from one another and arranged at a distance from one another on measuring chamber 22 a. A measurement point of the lambda probes 14 a, 16 a, 18 a, 20 ais preferably arranged within the measurement chamber 22 a. The lambda probes 14 a, 16 a, 18 a, 20 aare arranged in a plane which runs at least substantially perpendicular to the provided main flow direction 30 aof the process fluid through the measuring chamber 22 a. In particular, the respective main extension planes of the lambda probes 14 a, 16 a, 18 a, 20 aare oriented at least substantially perpendicular to the provided main flow direction 30 aof the process fluid through the measurement chamber 22 a. Preferably, a respective main extension direction of the lambda probes 14 a, 16 a, 18 a, 20 aruns radially with respect to the main flow direction 30 aof the process fluid through the measuring chamber 22 a. In particular, the lambda probes 14 a, 16 a, 18 a, 20 aare arranged in a star shape and are aligned with the main flow direction 30 awith their measurement points.Lambda sensors 14 a, 16 a, 18 a, 20 aare arranged at least substantially rotationally symmetrically with respect to provided main flow direction 30 aon measuring chamber 22 a. An angle between main directions of extension of each two adjacent lambda probes 14 a, 16 a, 18 a, 20 apreferably deviates from a rotationally symmetrical ideal value of this angle by less than 50%, preferably by less than 25%, particularly preferably by less than 10%, for all lambda probes 14 a, 16 a, 18 a, 20 a. The rotationally symmetrical ideal value is preferably equal to 360° divided by the number of lambda sensors 14 a, 16 a, 18 a, 20 aarranged in the same plane. In particular, the lambda probes 14 a, 16 a, 18 a, 20 ahave a four-fold rotational symmetry and a rotationally symmetrical ideal value of 90° in the plane in which they are arranged. Preferably, a minimum distance of the lambda probes 14 a, 16 a, 18 a, 20 afrom the fluid inlet 24 aand the fluid outlet 26 ais the same size except for a deviation of at most 50%, preferably at most 25%, particularly preferably at most 10%.The high temperature measuring device 10 apreferably comprises a fluid guiding unit 34 a. The fluid guidance unit 34 apreferably comprises a feed line element 60 awhich is connected to the fluid inlet 24 aof the measurement chamber 22 a, in particular projects through the fluid inlet 24 ainto the measurement chamber 22 a. The fluid guidance unit 34 apreferably comprises a discharge line element 62 awhich is connected to the fluid outlet 26 aof the measurement chamber 22 a, in particular projects through the fluid outlet 26 ainto the measurement chamber 22 a. The high temperature measuring device 10 ais preferably connected to the system fluid guiding unit 40 awith the fluid guiding unit 34 a. The discharge line element 62 aand / or the supply line element 60 aare designed, for example, as a 90° bending piece. The discharge line element 62 aand / or the supply line element 60 apreferably comprises at least one fastening element, here for example a union nut, alternatively a flange, for fastening the fluid guide unit 34 ato the system fluid guide unit 40 a.The high-temperature measuring device 10 aincludes an insulation housing 32 awhich at least substantially completely surrounds the measuring chamber 22 a. The insulation housing 32 ais, for example, of cylindrical design. Preferably, the insulation housing 32 aand the measuring chamber 22 aare arranged concentrically. The fluid guidance unit 34 aconstitutes at least one spacer, by means of which the insulation housing 32 aand the measuring chamber 22 aare arranged spaced apart from one another. Preferably, the insulation housing 32 ais fastened to the supply line element 60 aand / or the discharge line element 62 aat a distance from the measuring chamber 22 a.FIGS. 3 and 4 show further exemplary embodiments of the invention. The following descriptions and the drawings are limited substantially to the differences between the exemplary embodiments, wherein with regard to identically denoted components, in particular with regard to components with the same reference numerals, reference can in principle also be made to the drawings and / or the description of the other exemplary embodiments, in particular of FIGS. 1 to 2. To distinguish between the exemplary embodiments, the letter a is appended to the reference numerals of the exemplary embodiment in FIGS. 1 to 2. In the exemplary embodiments of FIGS. 3 and 4, the letter a is replaced by the letters b and c.FIG. 3 shows a high-temperature measuring device 10 bfor analyzing a composition of a process fluid of a chemical, in particular electrochemical, conversion. The high-temperature measuring device 10 bincludes at least one sensor unit 12 b, wherein the sensor unit 12 bincludes at least one Nernst cell in the form of a lambda probe 14 b, 16 b, 18 b, 20 bfor analyzing the process fluid. The high-temperature measuring device 10 bincludes at least one measuring chamber 22 bfor receiving the process fluid, wherein the sensor unit 12 bis at least partially arranged in the measuring chamber 22 b. The high-temperature measuring device 10 bincludes at least one fluid sample 28 bfor taking a measurement quantity of the process fluid from an external fluid line, such as the system fluid guidance unit 40 aof the electrochemical system 36 afrom FIG. 1 The fluid sample 28 bis preferably connected to a fluid guidance unit 34 b, in particular at least one supply line element 60 b, of the high-temperature measuring device 10 b. The fluid sample 28 bis preferably provided for introduction into the external fluid line in the manner of a Pitt tube.For further features of the high-temperature measuring device 10 b, reference is made to the description relating to FIGS. 1 and 2.FIG. 4 shows an electrochemical system 36 chaving a high-temperature measuring device 10 cto analyze a composition of a process fluid of a chemical, in particular electrochemical, conversion. The high-temperature measuring device 10 ccomprises at least one sensor unit 12 c, wherein the sensor unit 12 ccomprises at least one Nernst cell, in particular in the form of a lambda probe, for the analysis of the process fluid. The high temperature measuring device 10 ccomprises a measuring chamber 22 cto receive the process fluid, wherein the sensor unit 12 cis at least partially arranged in the measuring chamber 22 c. The high temperature measurement device 10 cis connected to a discharge branch 56 cof a system fluid guidance unit 40 cof the electrochemical system 36 c, which is connected to a product outlet 52 cof an electrochemical cell 38 cof the electrochemical system 36 c. The discharge branch 56 cpreferably comprises an afterburner 50 cto thermally convert fuel residues in a product of the electrochemical cell 38 c. The high-temperature measuring device 10 cis arranged in the discharge branch 56 cpreferably downstream of the afterburner 50 cto detect explosive constituents in an exhaust gas of the afterburner 50 c, in particular to monitor a distance from the lower explosion limit (UEG) of these constituents. The high-temperature measuring device 10 cis preferably arranged downstream of one, in particular all, product-reactant heat exchanger 46 cof the electrochemical system 36 c.With regard to further features of the electrochemical system 36c, reference is made to FIGS. 1 to 3.

Claims

High-temperature measuring device (10a; 10b; 10c) for analyzing a composition of a process fluid of a chemical, in particular electrochemical, conversion, having at least one sensor unit (12a; 12b; 12c), wherein the sensor unit (12a; 12b; 12c) comprises at least one Nernst cell, in particular in the form of a lambda probe (14a, 16a, 18a, 20a; 14b, 16b, 18b, 20b), for analyzing the process fluid, characterized bya measuring chamber (22a; 22b; 22c) for receiving the process fluid, wherein the sensor unit (12a; 12b; 12c) is arranged at least partially in the measuring chamber (22a; 22b; 22c).High temperature measuring device (10a; 10b; 10c) according to claim 1, characterized in that the measuring chamber (22a; 22b) comprises a fluid inlet (24a; 24b) and a fluid outlet (26a; 26b) arranged at a distance from the fluid inlet (24a; 24b).High temperature measuring device (10a; 10b; 10c) according to claim 1 or 2, characterized in that the fluid inlet (24a; 24b) and the fluid outlet (26a; 26b) are arranged at mutually opposite ends of a maximum longitudinal extension of the measuring chamber (22a; 22b).High-temperature measuring device (10b) according to one of the preceding claims, characterized byat least one fluid sample (28b) for taking a measurement quantity of the process fluid from an external fluid line.High temperature measuring device (10a; 10b; 10c) according to one of the preceding claims, characterized in that the sensor unit (12a; 12b; 12c) comprises at least two Nernst cells, wherein the Nernst cells are arranged in a plane which runs at least substantially perpendicular to a provided main flow direction (30a; 30b) of the process fluid through the measuring chamber (22a; 22b; 22c).High temperature measuring device (10a; 10b; 10c) according to one of the preceding claims, characterized in that the sensor unit (12a; 12b; 12c) comprises at least four Nernst cells, wherein the Nernst cells are arranged in a plane which runs at least substantially perpendicular to a provided main flow direction (30a; 30b) of the process fluid through the measuring chamber (22a; 22b; 22c).High-temperature measuring device (10a; 10b; 10c) according to Claim 4 or 5, characterized in that the Nernst cells are arranged on the measuring chamber (22a; 22b; 22c) at least substantially rotationally symmetrically with respect to the provided main flow direction (30a; 30b).High-temperature measuring device (10a; 10b; 10c) according to one of the preceding claims, characterized byan insulation housing (32a; 32b) which at least substantially completely surrounds the measuring chamber (22a; 22b).High-temperature measuring device (10a; 10b; 10c) according to Claim 8, characterized bya fluid guide unit (34a; 34b; 34c) for guiding the process fluid to and / or from the measuring chamber (22a; 22b; 22c), wherein the fluid guide unit (34a; 34b; 34c) forms at least one spacer, by means of which the insulation housing (32a; 32b) and the measuring chamber (22a; 22b; 22c) are arranged spaced apart from one another.Electrochemical system (36a; 36c) having at least one electrochemical cell (38a; 38c) and having at least one high-temperature measuring device (10a; 10c) according to one of the preceding claims, which is fluidically connected to the electrochemical cell (38a; 38c).Electrochemical system (36a; 36c) according to claim 10, characterised bya system fluid guidance unit (40a; 40c) for guiding the at least one process fluid from and / or to the at least one electrochemical cell (38a; 38c), wherein the high temperature measuring device (10a; 10c) is connected to the system fluid guidance unit (40a; 40c) in the form of a bypass.

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