Fixed bed reactor for realizing in-situ heat removal and in-situ temperature measurement of strong exothermic reaction based on thermally induced power generation principle

Abstract

The invention relates to the field of fixed bed devices for reusing reaction heat of exothermic reactions, in particular to a fixed bed reactor for realizing in-situ heat removal and in-situ temperature measurement of a strong exothermic reaction based on a thermally induced power generation principle, and particularly relates to a fixed bed reactor for realizing in-situ temperature measurement of the strong exothermic reaction based on the thermally induced power generation principle. Meanwhile, exothermic reaction temperature and heat can be measured and monitored from multiple angles, heat transfer of a catalytic bed is enhanced, reaction hot spots are effectively eliminated or reduced, and catalyst deactivation is avoided. The device comprises a fixed bed reaction tube, and an infrared temperature measurement system and a potential detection and electric energy collection system are arranged at the top end of the fixed bed reaction tube. A gas inlet and a gas outlet are formed in the side end of the fixed bed reaction tube The fixed bed reaction tube is provided with a thermocouple inlet; the ratio of the material and the pipe diameter of the reaction pipe to the wire meets the requirements of infrared temperature measurement, electric energy collection and potential and temperature detection at the same time, and temperature and electric energy collection and potential and temperature detection are realized under the condition that the catalytic reaction process is not influenced; and a catalyst and a thermally induced power generation composite material are filled in the reaction tube.

Description

Technical Field

[0001] The invention relates to a reactor suitable for thermal power generation to realize in-situ heat removal and in-situ temperature measurement of gas phase exothermic reaction, and particularly to a fixed bed reactor suitable for acetylene hydrogenation to ethylene reaction. Background Art

[0002] Many important chemical processes are highly exothermic heterogeneous catalytic reactions, such as acetylene hydrogenation, where the total enthalpy change is -176 kJ·mol -1 The total reaction enthalpy change of the side reaction acetylene hydrogenation to ethane is as high as -312 kJ·mol -1 During the reaction, a large amount of heat will be released instantly. If the heat cannot be removed quickly, the large amount of heat released instantly by the reaction will easily cause local overheating, which will not only increase the probability of side reactions, but also instantly cause the catalyst to fail, resulting in unstable reaction conversion rate and selectivity, and reduce system efficiency; more seriously, the instantaneous release of a large amount of heat can easily cause system temperature rise, pressure loss and other problems, which may damage the process equipment at the least, or cause major safety accidents such as explosion, fire and casualties at the worst. Therefore, in order to ensure the normal progress of the catalytic reaction, heat removal is required in time.

[0003] In view of the strong exothermic reaction, people have designed many types of reactors and proposed many heat removal methods. Patent CN118253267A proposes a reaction heat utilization device for the process of preparing 1,2-dichloroethane by ethylene oxychlorination. The fluidized bed reactor device is divided into a dense phase zone and a dilute phase zone. By setting a heat exchange tube bundle in the dilute phase zone, the raw gas is preheated by the reaction gas, the waste heat of the gas phase product is drawn out, the entrainment loss of the catalyst is reduced, the equipment investment is reduced, and the energy consumption is reduced; by secondary addition of raw gas and heat extraction diversion, the raw gas is added separately, and the bottom reaction heat is guided to the heat removal tube bundle, which improves the selectivity and purity of 1,2-dichloroethane. However, the heat conductive sheet only removes part of the surrounding heat and cannot solve the "hot spots" of the catalyst bed. CN1260237A proposes to use heat-conducting metal particles as inert diluents in exothermic reactions to reduce and avoid the formation of hot spots in the fixed bed. This method only transfers heat from the catalytic active sites to the diluent and does not fully utilize the heat. As a functional material that can realize the bidirectional conversion of heat energy and electrical energy, thermoelectric materials have shown great application potential in the fields of waste heat utilization and solid-state refrigeration technology, providing an innovative solution to the current energy shortage problem. Thermoelectric materials are the core of thermoelectric power generation, and their performance directly affects the efficiency of thermal energy conversion. Based on thermoelectric power generation, the heat of the exothermic reaction is removed while the temperature is measured and the electrical energy is stored, which can avoid the problem of catalyst deactivation caused by additional heat generation. Summary of the invention

[0004] The purpose of the present invention is to provide a fixed bed temperature measuring reactor based on the concept of thermoelectric generation, which can enhance the heat transfer of the catalytic bed, dope thermoelectric generation materials with catalysts to prepare composite materials, directly convert thermal energy into electrical energy through thermoelectric generation, and realize the removal of heat from highly exothermic reactions; on the other hand, the temperature of the reaction process is detected in situ through the electrical signal intensity of the thermoelectric generation material and the electrical energy is collected.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A fixed bed reactor suitable for in-situ heat removal and in-situ temperature measurement of a gas phase exothermic reaction, such as Figure 1 As shown, it includes a heating jacket and a fixed bed reaction tube; the fixed bed reaction tube 3 is inserted into the heating jacket 2; a catalyst bed 4 is arranged in the fixed bed reaction tube, and the catalyst bed is a composite material of acetylene selective hydrogenation to ethylene catalyst and thermoelectric material, and the upper and lower ends of the catalyst bed are provided with terminals for connecting wires; the two ends of the fixed bed reaction tube are respectively provided with an air inlet 5 and an air outlet 6, and the air inlet and outlet are both at the side ends; the top of the fixed bed reaction tube 3 is made of replaceable material. A thermocouple 7 is arranged in the tube, one end of which is in contact with the catalyst bed, and the other end extends out of the fixed bed reaction tube.

[0007] The constant temperature of the catalytic bed is a basic requirement to ensure the normal progress of the catalytic process. However, the lens of the infrared thermometer 1 is relatively large. If the infrared temperature measurement is performed on the side of the fixed bed, the insulation effect of the heating furnace will be affected, thereby affecting the progress of the catalytic process. As mentioned above, the present invention measures the temperature of the fixed bed at the top of the reaction tube.

[0008] The rechargeable battery, the potentiometer, the external catalyst filling box and the catalyst bed are connected to form a closed loop.

[0009] like Figure 2 As shown, it is an electric signal detection and storage system. The electric signal detection and storage system includes a potentiometer 8, a rechargeable battery 9, an external catalyst filling box 10, and an external catalyst 11. As mentioned above, the catalyst bed is provided with a terminal, and the catalyst, the potentiometer, the rechargeable battery, and the external catalyst are connected in a series circuit by wires. Based on the exothermic reaction of the catalyst bed 4 in the fixed bed reaction tube when the acetylene selective hydrogenation reaction occurs, a temperature difference is generated between the catalyst 4 and the external catalyst 11. According to the principle of thermoelectric generation, the thermoelectric material releases electrons through the entire series circuit and is stored in the rechargeable battery 9; the temperature measurement can be achieved by detecting the strength of the electric signal through the potentiometer 8.

[0010] like Figure 3As shown, the catalyst loading and support frame. The catalyst support frame includes a conductive aluminum material 12; a fastener (insulator) 13; a conductive aluminum rod 14; an upper terminal nut 16; an upper terminal 17; a lower terminal 18; and a lower terminal nut 19. The upper and lower conductive aluminum materials and the catalyst module are fixed in the fixed bed reaction tube by the fastener 13. As mentioned above, one end of the conductive aluminum rod is connected to the upper conductive aluminum material, and the other end extends to the lower end of the catalyst bed and is connected to the upper terminal nut 16 and the upper terminal so as to be connected to the above series circuit.

[0011] like Figure 4 , 5 As shown, a schematic diagram of the catalyst. The catalyst is honeycomb-shaped, and three fastener holes 13 and conductive aluminum rod 14 are additionally designed. The catalyst for the selective hydrogenation of acetylene is a Pd-based, Ni-based, or Cu-based catalyst, and the thermoelectric material is a thermoelectric material bismuth telluride. The currently purchased acetylene selective hydrogenation catalyst is physically mixed with a thermoelectric material to form a composite material as a catalyst, which has hydrogenation properties for the reaction and removes the heat of the in-situ exothermic reaction.

[0012] Beneficial effects of the present invention:

[0013] 1. Compared with the prior art, based on the principle of thermoelectric power generation, this application proposes to remove the heat of the exothermic reaction and avoid the generation of hot spots in the catalytic bed by combining the acetylene selective hydrogenation catalyst with a thermoelectric material while ensuring the normal progress of the catalytic reaction and without increasing the processing difficulty of the reactor.

[0014] 2. This application combines infrared temperature measurement, electrical signal detection and collection, and a fixed bed reactor, and designs the inner diameter, material, and inlet and outlet modules of the fixed bed reaction tube to meet the detection conditions, facilitate real-time monitoring of the reaction process, and perform temperature measurement at multiple angles, thereby obtaining the true temperature of the catalytic reaction, further analyzing the catalytic process, and improving the objective effectiveness of the catalyst performance evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of a fixed bed reactor and an infrared temperature measurement system of the present invention;

[0016] Figure 2 It is a schematic diagram of a fixed bed reactor and an electrical signal detection and storage system of the present invention;

[0017] Figure 3 Catalyst loading and support frame for the fixed bed reactor of the present invention;

[0018] In the figure, 1. infrared thermal imaging thermometer; 2. heating jacket; 3. fixed bed reaction tube; 4. catalyst bed; 5. air inlet; 6. air outlet; 7. thermocouple; 8. potentiometer; 9. rechargeable battery; 10. external catalyst placement rack; 11. external catalyst; 12. conductive aluminum material; 13. fastener (insulator); 14. conductive aluminum rod; 15. catalyst module; 16. upper terminal nut; 17. upper terminal; 18. lower terminal; 19. lower terminal nut

[0019] Figure 4 This is a front view of the catalyst of the fixed bed reactor of the present invention;

[0020] Figure 5 It is a top view of the catalyst of the fixed bed reactor of the present invention. DETAILED DESCRIPTION

[0021] The novel technical solution of the present invention is further described in detail below, but is not intended to be a limitation of the present invention.

[0022] A fixed bed reactor suitable for thermal power generation to realize in-situ heat removal of strong exothermic reaction, comprising a fixed bed reaction tube, and an infrared temperature measurement system is arranged on the top of the fixed bed reaction tube. The fixed bed reaction tube has an air inlet and an air outlet at the side end; the fixed bed reaction tube is provided with a thermocouple inlet; a catalyst bed 4 is arranged in the reaction tube, and the catalyst bed 4 is loaded with a catalyst; a heating jacket 3 is arranged outside the fixed bed reaction tube 3, and a thermocouple is arranged below the fixed bed reaction tube; an electrical signal detection and storage system comprises a potentiometer 8, a rechargeable battery 9, an external catalyst filling box 10, and an external catalyst 11.

[0023] The temperature is measured at the top of the fixed bed reaction tube, and the side end is the air inlet, so as to ensure the temperature of the catalyst bed.

Claims

1. A fixed bed reactor suitable for in-situ heat removal and in-situ temperature measurement of gas phase exothermic reactions, characterized in that: It comprises a heating jacket and a fixed bed reaction tube; a heating jacket is arranged outside the fixed bed reaction tube; a catalyst bed is arranged inside the fixed bed reaction tube; an air inlet and an air outlet are arranged at both ends of the fixed bed reaction tube; a thermocouple is arranged inside the fixed bed reaction tube, one end of the thermocouple extends to the catalyst bed, and the other end extends outside the fixed bed reaction tube; It also includes at least one of an electric signal detection and storage system and an infrared temperature measurement system.

2. A fixed bed reactor suitable for in-situ heat removal and in-situ temperature measurement of a gas phase exothermic reaction according to claim 1, characterized in that: An infrared temperature measurement system and an electric energy storage system are arranged on the top of the reaction tube of the fixed bed.

3. A fixed bed reactor suitable for in-situ heat removal of gas phase exothermic reaction and simultaneous in-situ temperature measurement and electrical energy storage according to claim 1, characterized in that: When the infrared temperature measurement system is used, the top of the fixed bed reaction tube is germanium glass.

4. A fixed bed reactor suitable for in-situ heat removal of gas phase exothermic reaction and simultaneous in-situ temperature measurement and electrical energy storage according to claim 1, characterized in that: The electric energy storage system comprises a rechargeable battery, a potentiometer, an external catalyst filling box and an external catalyst; the rechargeable battery, the potentiometer, the external catalyst filling box and the catalyst bed are connected to form a closed loop.

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