RU1800347C - Electrical thermograph - Google Patents

Abstract

The invention relates to analytical instruments, in particular for measuring the dynamic characteristics of heterogeneous catalytic reactions. SUBSTANCE: electrothermograph contains a flow-through reaction measuring cell, in the channel of which a wire catalytic thermal sensor is installed, connected in series to. closed circuit with an electric current source. There is a unit for measuring the current-voltage characteristics of the temperature sensor, a unit for controlling its temperature mode. A source of high voltage, an inert electrode installed in the channel of the reaction cell, temperature sensors, and a discharge current measuring unit are introduced into the circuitry. These elements form an open loop. 4 ill.

Description

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The invention relates to analytical instruments for measuring the dynamic patterns of heterogeneous catalytic reactions. It can be used in calorimetry and thermography.

The purpose of the invention is to continuously measure the amount of sublimation of the catalyst material during the heterogeneous catalytic reaction.

This goal is achieved by the fact that in an electrothermograph containing a flashing reaction measuring cell, in the channel of which a wire catalytic thermal sensor is installed, connected in series to a closed loop with an electric current source, a unit for measuring the current-voltage characteristics of the temperature sensor. the sensor, the temperature control unit, the temperature sensor mode further comprises an inert electrode, a high voltage source, a discharge current measuring unit, connected in series to an open circuit with a wire catalytic temperature sensor, the inert electrode being installed in the channel of the reaction cell.

With this introduction of a high voltage open circuit in this connection with the other elements of the circuit, the inventive device begins to exhibit an additional property. This new property consists in the fact that the parameter of the discharge current through the gas gap is linearly related to the intensity (speed) of sublimation of the catalyst material during the passage of a heterogeneous catalytic reaction on its surface. This fact was established and confirmed using specially conducted parallel gravitational measurements.

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rhenium wire catalytic thermal sensor (sample).

Figure 1 presents a diagram of an electrothermograph; Figures 2 and 3 show the results of using, respectively, the standard gravity method and a device for measuring the magnitude of the intensity, sublimation of the catalyst material during the heterogeneous catalytic reaction; Fig. 4 shows a linear dependence of the detected discharge current through the gas gap on the sublimation intensity (speed).

Example. The electrothermograph (Fig. 1) contains a flow-through reaction measuring cell 1, in the channel of which a wire catalytic thermal sensor 2 is installed, connected in series to a closed loop with an electric current source 3, a unit for measuring the current-voltage characteristics of the temperature sensor 4, and a temperature control unit for the wire catalytic temperature sensor 5 , an inert electrode 7, which is installed in the channel of the reaction cell 1, a high voltage source 6, a discharge current measuring unit 9, sequentially connected to open loop with wire catalytic thermal sensor 2.

The device operates as follows.

The reaction mixture with a given composition, temperature and speed is passed through the channel of the reaction measuring cell, in which the wire catalytic thermal sensor 2 and electrode 7 are installed. The temperature sensor is heated from the electric current source 3. Measurement of the joule power and electrical resistance heated by the electric current of temperature sensor 2, on the surface of which a heterogeneous-catalytic reaction occurs, it is carried out by a unit for measuring the current-voltage characteristics 4, which is necessary for the study The temperature regime of the catalytic surface reaction is established due to a change in the Joule power released at the temperature sensor and is carried out by the temperature control unit 5. The rate of reaction heat generation or heat absorption is extracted from the initial current-voltage characteristics, provided that there is information about the heat exchange between the sensor and the reaction Wednesday. The procedure for isolating the reaction component of the heat signal is reduced to comparing two electrothermograms, one of which is taken in the flow of reagents, and the other in an inert mixture simulating the reaction medium according to its thermophysical properties. In order to continuously measure the sublimation rate of the catalyst material simultaneously with the reaction rate, an additional electric circuit is opened from the gas gap 8. From the temperature sensor 2, the high voltage source b, the inert electrode 7 and the discharge current measuring unit 9, they are opened by the gas temperature sensor 8. 2

chemical reaction in the specified additional electrical circuit appears a new component of the electric current, linearly related to the sublimation rate of the catalyst material. Value

5, the current through the gas gap is recorded by the discharge current measuring unit 9. The initial parameter, the sublimation rate of the catalyst material, is determined by comparing the temperature-current dependences of the inert and catalytic wire temperature sensors.

As an example, FIGS. 2 and 3 show comparative results of using, respectively, gravitational

5 methods and the proposed device. Comparative tests were carried out on a round cross section wire catalyst element, 0.1 mm in diameter, made of technically pure platinum. Kon0

centralization of ammonia in oxygen-ammonia

the mixture was 10% (vol.), the gas flow temperature was -20 ° С, the velocity was -10 cm / s, the temperature of the sensor was 780-800 ° С, the pressure was atmospheric, the potential difference between electrode 7 and temperature sensor 2 was 4.0 kV. A comparison of the presented results shows that the proposed device for measuring the sublimation intensity of the catalyst material is more preferable, both from the point of view of ensuring the continuity of the process registration, sublimation of the catalyst material simultaneously with the reaction rate, and

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sight of the accuracy of the measurements.

Claims (1)

Figure 4 shows the sought-after linear dependence of the sublimation rate of the catalyst material on the magnitude of the recorded discharge current through the gas gap 8 for the above samples. SUMMARY OF THE INVENTION An electrothermograph comprising a flow-through reaction measuring cell in the channel of which is installed 5 wire catalytic thermal sensor, sequentially included in a closed circuit with a source of electric current, v is a unit for measuring the current-voltage characteristics of a wire catalytic temperature sensor and a unit for controlling its temperature, characterized in that, in order to ensure continuous measurement of the sublimation of the catalyst material during the heterogeneous-catalytic reaction, it additionally contains an inert electrode, source high voltage, discharge current measuring unit, connected in series to an open circuit with a wire catalytic thermal sensor, the inert electrode being installed in the channel of the reaction cell. 7} in i fr b. CVGC