FIXED BED REACTOR BASED ON THE PRINCIPLE OF THERMOLUMINESCENCE FOR IN-SITU HEAT REMOVAL AND IN-SITU TEMPERATURE MEASUREMENT OF STRONG EXOTHERMIC REACTIONS

Abstract

A fixed bed reactor based on the principle of thermoluminescence to achieve in-situ heat removal and in-situ temperature measurement for strong exothermic reactions can monitor the temperature and heat of the exothermic reaction process from multiple angles, enhance the heat transfer of the catalytic bed layer, and effectively reduce or eliminate the hot spots generated by the exothermic reaction process. This reactor includes a fixed bed reaction tube, and the top of the fixed bed reaction tube is equipped with a xenon lamp pretreatment system, an optical signal detection system, and an infrared temperature measurement system.

Claims

1. A fixed bed reactor suitable for in-situ heat removal and in-situ temperature measurement in gas-phase exothermic reactions, comprising a heating jacket and a fixed bed reaction tube, wherein the heating jacket is installed outside the fixed bed reaction tube, a catalyst bed is installed inside the fixed bed reaction tube, a catalyst and a thermally luminescent material are placed inside the catalyst bed layer, two ends of the fixed bed reaction tube are respectively equipped with inlet and outlet ports, with inlet at the side and outlet at the lower end, a thermocouple is installed inside the fixed bed reaction tube, with one end extending to the catalyst bed and the other end extending outside the fixed bed reaction tube, and the fixed bed reactor further comprises at least one of a xenon lamp pretreatment system, an optical signal detection system, and an infrared temperature measurement system.

2. The fixed bed reactor according to claim 1, wherein the temperature and optical signal are measured at the top of the fixed bed reaction tube.

3. The fixed bed reactor according to claim 1, wherein the xenon lamp pretreatment system comprises a xenon lamp, when pretreatment of thermally luminescent materials is required, align the xenon lamp probe with the catalyst bed inside the reaction tube, after irradiating the stored electrons, the catalytic bed is then heated by introducing an inert gas or reaction gas atmosphere.

4. The fixed bed reactor according to claim 1, wherein the optical signal detection system comprises a reflector, a condenser, a monochromator, and a detector, when the top of the fixed bed reaction tube is made of quartz, measure the light intensity, the optical signal collection system is located at the top of the reaction tube, with the reflector and condenser in the darkroom, the thermochromic material in the catalytic bed emits light due to the release of electrons after heating up, which is refracted 90 by the reflector and converged by the condenser into the monochromator, the measured wavelength of light is selected and the intensity of the optical signal is measured by a detector, the detector converts the optical signal into an electrical signal to achieve optical signal intensity detection.

5. The fixed bed reactor according to claim 1, wherein when the top of the fixed bed reaction tube is made of germanium glass, the temperature of the catalytic bed layer is measured by infrared temperature measurement.

6. A method for producing a fixed bed reactor according to claim 1, wherein the method is used for acetylene hydrogenation to produce ethylene, the catalysts are Pd based, Ni based, Cu based catalysts, and the luminescent materials are rare earth doped calcium fluoride, lithium fluoride, calcium sulfate, and lithium borate, physically mixing the catalyst with thermally luminescent materials or doping or depositing rare earth elements onto the catalyst, followed by pretreatment and measurement of optical signals or temperature.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a schematic diagram of the fixed bed reactor and xenon lamp pretreatment system of the present application.

[0016] FIG. 2 is a schematic diagram of the fixed bed reactor and optical signal measurement system of the present application.

[0017] FIG. 3 is a schematic diagram of the fixed bed reactor and infrared temperature measurement system of the present application.

[0018] FIG. 4 shows the photocurrent testing of different materials.

[0019] FIG. 5 shows the photoluminescence spectra of different materials.

[0020] FIG. 6 shows the thermal release spectrum of LiF.

[0021] FIG. 7 shows the thermal release spectrum of CaF2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The following provides a further detailed explanation of the novel technical solution of the present application, but it is not intended to be a limitation of the present application.

[0023] A fixed bed reactor suitable for achieving strong exothermic reaction in situ heat removal through thermoluminescence includes a fixed bed reaction tube, and the top of the fixed bed reaction tube is equipped with one of a xenon lamp pretreatment system, a light signal detection system, and an infrared temperature measurement system. The side end of the fixed bed reaction tube is the inlet, and the lower end is the outlet. The fixed bed reaction tube is equipped with a thermocouple inlet. A catalyst bed 3 is installed inside the reaction tube, which is filled with catalyst. A heating jacket 4 is installed outside the fixed bed reaction tube 2, and a thermocouple is installed below the fixed bed reaction tube. The optical signal detection system sequentially includes a reflector 8, a spotlight 9, a monochromator 10, and a detector 11. Mirror 8 and spotlight 9 are set in darkroom 12.

[0024] The optical signal or temperature is measured at the top of the fixed bed reaction tube, and there is an inlet on the side of the fixed bed reaction tube to ensure the temperature of the catalytic bed layer.

[0025] The ability of the thermally luminescent material to store electrons was determined through photocurrent testing and photoluminescence spectroscopy, as shown in FIGS. 4 and 5.

Example 1

[0026] As shown in FIG. 1, it is a xenon lamp pretreatment system. The xenon lamp pretreatment system includes xenon lamp 7. When pre-treatment of thermally luminescent materials is required, align the xenon lamp probe with the catalyst bed inside the reaction tube to ensure uniform irradiation. According to the trap energy level depth formula

[00001]$E=\frac{2k{T}_n^2}{},$

where k is the Boltzmann constant, Tn is the temperature value corresponding to the peak of the thermoluminescence curve, and is a parameter related to the temperature at half the peak intensity. The depth of defects in different materials varies, and the amount of electrons they can store also differs. Based on the principle of thermoluminescence, luminescent materials need to store electrons and release them to recombine with holes during the heating process to emit light. luminescent materials are illuminated by ultraviolet rays to store electrons. The amount of electrons stored in luminescent materials can be observed based on the height of the peak of the thermoluminescence curve observed at different irradiation times. When the peak intensity is the highest, it represents the highest amount of electron storage at this time, and the optimal time for ultraviolet treatment is at this time. After storing electrons under ultraviolet irradiation, inert gas or reaction gas atmosphere is then introduced to heat up the catalytic bed.

Example 2

[0027] As shown in FIG. 2, it is an optical signal detection system. The optical signal measurement system includes a reflector 8, a condenser 9, a monochromator 10, a detector 11, and a darkroom 12. As mentioned earlier, the top of the fixed bed reaction tube is made of replaceable material, and when replaced with quartz, light intensity measurement is performed. The optical signal collection system is located at the top of reaction tube 2, and the entire optical signal collection part is in darkroom 12. The thermochromic material in catalytic bed 3 emits light due to the release of electrons after heating up, which is refracted by mirror 8 at a 90 angle and converged by condenser 9 before being introduced into monochromator 10. The measured wavelength of light is selected and the optical signal intensity is measured by detector 11. The detector converts the optical signal into an electrical signal to detect the intensity of the optical signal. Based on the principle of exothermic reaction and thermoluminescence, the heat released by the exothermic reaction is removed by converting thermal energy into light energy. At the same time, temperature measurement can be achieved by comparing the intensity of light signal detection under inert atmosphere and reactive gas atmosphere.

Example 3

[0028] As shown in FIG. 3, it is an infrared temperature measurement system. The infrared temperature measurement system includes infrared thermal imaging 13. Infrared temperature measurement is based on the infrared radiation emitted by an object, and calculates the surface temperature of the object through the relationship between radiation power and temperature. Infrared temperature measurement in a reactor requires ensuring the passage of infrared radiation. As mentioned earlier, when the top of the fixed bed reaction tube 2 is replaced with germanium glass, germanium glass can ensure the passage of infrared radiation, allowing for temperature measurement of the catalytic bed layer through infrared temperature measurement. When accurately measuring the temperature of the catalytic bed, infrared thermography 13 can be used for temperature measurement.

Example 4

Pd/TiO.sub.2 Catalyst, Thermally Luminescent Material CaF.sub.2

[0029] Firstly, add 0.1 g CaF.sub.2 to the fixed bed reactor. Next, select 365 nm wavelength ultraviolet light with a xenon lamp and irradiate it for 15 minutes at a distance of 15 cm from CaF.sub.2 at the top of the reaction tube under the irradiation intensity of 0.51 W/m.sup.2. Next, 115 ml/min of N.sub.2 was introduced under one atmosphere pressure, and the material was heated from room temperature to 250 C. at a rate of 5 C./min. Thermoluminescence spectroscopy was performed using a light signal detection system to obtain the relationship between temperature and the ratio of thermoluminescence intensity. Then, 0.1 g of Pd/TiO.sub.2 catalyst was physically mixed with 0.1 g of CaF.sub.2, and 365 nm wavelength ultraviolet light was selected using a xenon lamp. The reaction tube was irradiated for 15 minutes at a distance of 15 cm from CaF.sub.2 at the top. Then, 100 ml/min of 1% C.sub.2H.sub.2/C.sub.2H.sub.4 and 15 ml/min of 10% H.sub.2/N.sub.2 were introduced under atmospheric pressure for hydrogenation reaction. The material was heated at a rate of 5 C./min from room temperature to 150 C., and the light intensity was detected using a light signal detection system. The actual temperature of the catalytic reaction was calculated by inputting the thermoluminescence intensity ratio at this temperature into the standard thermoluminescence temperature measurement curve.

Example 5

PdCu MMO Catalyst and Pr.sup.3+ Doped Y.sub.3Al.sub.2Ga.sub.3O.sub.12 Thermally Luminescent Material

[0030] Firstly, 0.5 g of Pr.sup.3+ doped Y.sub.3Al.sub.2Ga.sub.3O.sub.12 was added to a fixed bed reactor. Then, 365 nm wavelength ultraviolet light was selected using a xenon lamp and irradiated for 15 minutes at a distance of 15 cm from Pr.sup.3+ doped Y.sub.3Al.sub.2Ga.sub.3O.sub.12 at the top of the reaction tube under an irradiation intensity of 0.51 W/m.sup.2. Then, 60 ml/min of N.sub.2 was introduced under one atmosphere pressure, and the material was heated from room temperature to 250 C. at a rate of 5 C./min. Thermoluminescence spectroscopy was performed using a light signal detection system to obtain the relationship between temperature and the ratio of thermoluminescence intensity. Then, 0.5 g of PdCu MMO catalyst was physically mixed with 0.5 g of Pr.sup.3+ doped Y.sub.3Al.sub.2Ga.sub.3O.sub.12. Similarly, 365 nm wavelength ultraviolet light was selected using a xenon lamp and irradiated for 15 minutes at a distance of 15 cm from the Pr.sup.3+ doped Y.sub.3Al.sub.2Ga.sub.3O.sub.12 at the top of the reaction tube. Then, 50 ml/min of 1% C.sub.2H.sub.2/C.sub.2H.sub.4 and 10 ml/min of 10% H.sub.2/N.sub.2 were introduced under atmospheric pressure for hydrogenation reaction. The material was heated at a rate of 5 C./min from room temperature to 200 C., and the light intensity was detected using a light signal detection system. The actual temperature of the catalytic reaction was calculated by inputting the thermoluminescence intensity ratio at this temperature into the standard thermoluminescence temperature measurement curve.