A high spatial resolution continuous flow reaction calorimetry system and calorimetry method

Abstract

This invention belongs to the field of chemical reaction heat measurement technology, specifically, it relates to a high spatial resolution continuous flow reaction calorimetry system and method. It includes a microreactor, flexible heaters, Seebeck elements, Peltier elements, and a thermostatic block. The flexible heaters are connected to a DC power supply and a central control unit. The computer controls the output voltage of the DC power supply to adjust the heat output. A second flexible heater above the microreactor is used to regulate the reaction temperature, while a first flexible heater below is used for calibration. The Seebeck element converts the temperature difference between the upper and lower surfaces into an electrical signal, which is monitored in real time by connecting to the central control unit. The Peltier element is connected to the central control unit and, combined with temperature sensor measurement and a PID control algorithm, cools the microreactor. The cooling capacity is adjusted by dynamically regulating the input voltage of the Peltier element to maintain a constant temperature in the microreactor. The thermostatic block is connected to a circulating oil bath. The calorimetry system is covered with insulation material.

Description

Technical Field

[0001] This invention belongs to the field of chemical reaction heat measurement technology, specifically, it relates to a high spatial resolution continuous flow reaction calorimetry system and calorimetry method. Background Technology

[0002] In industries such as chemical and pharmaceutical, highly exothermic reactions are ubiquitous, including processes such as nitration, diazotization, and oxidation. Reaction calorimetry can accurately measure the heat released during a reaction, which is essential for the safe operation of these processes. Furthermore, accurate and reliable calorimetric data are crucial for constructing reaction kinetic models, reactor design, process development, and scale-up.

[0003] Currently, reaction calorimetry is mainly performed in batch calorimeters. These calorimeters typically have a large liquid holdup, resulting in low mass and heat transfer efficiency, and uneven temperature and concentration distribution within the batch. These shortcomings not only lead to deviations in measurement results but also pose safety hazards. Furthermore, batch calorimeters cannot perform calorimetry on ultrafast reactions with reaction times on the order of seconds or even milliseconds. Although the reaction rate can be reduced by lowering the temperature, it is still difficult to improve the selectivity of such reactions. The generation of numerous byproducts makes the test results difficult to repeat and unreliable.

[0004] In continuous flow reactors, reactants mix rapidly, achieve uniform concentrations, and maintain precise temperature control. The combination of continuous flow technology and calorimetry makes calorimetric studies of strongly exothermic and rapid reactions safer, consumes less material, and yields more accurate results, also enabling the calorimetry of ultrafast reactions. Currently, although there are some reports on calorimetric methods for continuous flow reactions, none can achieve high-resolution real-time calorimetry at different points in the continuous flow reaction process. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies. This invention provides a high spatial resolution continuous flow reaction calorimetry system and method, which is a high spatial resolution continuous flow reaction calorimetry system and method based on thermoelectric effect. It can perform high-resolution real-time calorimetry on different parts of the continuous flow reactor at different reaction temperatures and measure the reaction enthalpy. Moreover, the calorimetry system does not require an external source to control the reaction temperature.

[0006] To achieve the above objectives, the present invention provides a high spatial resolution continuous flow reaction calorimetry system and method, implemented using the following technical solution:

[0007] This invention provides a high spatial resolution continuous flow reaction calorimetry system, including a microreactor, a flexible heater, a Seebeck element, a Peltier element, and a thermostat.

[0008] The components are connected by direct contact, and the heat conduction between the components can be enhanced by applying thermal grease to the surface.

[0009] The flexible heaters are connected to a DC power supply and then to a central control unit. The output voltage of the DC power supply is controlled by a computer to adjust the heating capacity. The second flexible heater above the microreactor is used to regulate the reaction temperature, while the first flexible heater below is used for calibration.

[0010] Seebeck elements convert the temperature difference between the upper and lower surfaces into electrical signals, which are then monitored in real time by connecting to the central control unit.

[0011] The Peltier element is connected to the central control unit. Combined with temperature sensor measurement and PID control algorithm, it cools the microreactor. The cooling capacity is adjusted by dynamically adjusting the input voltage of the Peltier element to maintain a constant temperature in the microreactor.

[0012] The thermostatic block is connected to the circulating oil bath and is used to remove the heat generated on the upper surface of the Peltier element;

[0013] The heating system is covered with insulation material to reduce heat exchange with the outside environment.

[0014] The microreactor employs a modular design, consisting of three parts: a preheating / precooling module, a reaction module, and a quenching module. The preheating / precooling module heats or cools the reactants to reach the target reaction temperature before the chemical reaction begins. The reaction module carries out the chemical reaction. The quenching module quenches the reaction, stopping it from proceeding. Only necessary piping connections are maintained between modules to minimize heat conduction between them. The channel configuration within each module can be customized, and the liquid holdup can be adjusted; a smaller liquid holdup results in higher heat flow resolution. The number of modules can be increased or decreased according to actual reaction requirements.

[0015] The upper and lower surfaces of the microreactor need to undergo surface treatment to reduce roughness. The microreactor can be made of materials with good thermal conductivity and corrosion resistance, such as stainless steel, Hastelloy, silicon carbide, and ceramics. The reactor can withstand pressures of over 4 MPa.

[0016] The microreactor is a planar reactor with an internal channel size of <1mm.

[0017] The size and number of flexible heaters, Seebeck elements, and Peltier elements need to correspond to the number of modules in the microreactor in order to enable individual monitoring and control of each module.

[0018] The preheating / precooling module of the microreactor is connected to two feed pumps at its front end. These pumps have volumetric metering capabilities for quantitative delivery of the reaction medium. The quenching module of the microreactor is connected to a feed pump on its side for quantitative delivery of the reaction quenching medium. The outlet of the quenching module can be connected to a product collection device for analyzing reaction products and determining the conversion rate of the reaction medium. Temperature sensors are installed inside each module, between the preheating / precooling module and the reaction module, and between the reaction module and the quenching module. These temperature sensors are connected to the central control unit to monitor the temperature at each location.

[0019] This system regulates the reaction temperature through the synergistic effect of a flexible heater and a Peltier element. The adjustable range depends on the performance of both elements, and this temperature range can be further extended using a circulating oil bath. During the experiment, temperature, voltage, and other signals are monitored and controlled via a central control unit and a control computer. All data monitored by this system is automatically saved to the control computer for subsequent analysis.

[0020] The flexible heater can be of different types, such as a polyimide film heater, a silicone heater, or a polyester heater.

[0021] Both the Seebeck element and the Peltier element are thermoelectric elements. The Seebeck element converts a thermal signal into an electrical signal, while the Peltier element converts an electrical signal into a thermal signal. When the Peltier element is energized, its cold side is in contact with the Seebeck element, and its hot side is in contact with the thermostatic block.

[0022] The constant temperature block is a heat exchange device that is hollow inside or has a specific configuration.

[0023] The calorimetric system described herein is applicable to various types of exothermic reactions, including homogeneous liquid-liquid or gas-gas reactions, heterogeneous liquid-liquid reactions, and heterogeneous gas-liquid reactions.

[0024] The calorimetric system described above can perform high-resolution real-time calorimetry on different parts of a continuous flow reactor at different reaction temperatures, and the resolution can be adjusted by designing the reaction channels.

[0025] The high spatial resolution continuous flow reaction calorimetry system refers to the ability to perform reaction calorimetry on reaction channels of arbitrary length through microreactor module design, characterizing the heat release of the reaction in each module.

[0026] The calorimetric system has a built-in heater and cooler, eliminating the need for an external source for temperature regulation, and it also has a built-in calibrator, eliminating the need for external calibration.

[0027] The calorimetric system described above can realize the reaction calorimetry of ultra-fast (<10s) strongly exothermic reactions.

[0028] The calorimetric system has a small liquid holding capacity, which can reduce reagent consumption and improve calorimetric safety.

[0029] This invention also provides a calorimetric method for a high spatial resolution continuous flow reaction calorimetric system, comprising the following three steps: The specific steps are as follows:

[0030] Step 1: Calibration. Set the circulating oil bath temperature to T0. After the temperature stabilizes, set the temperature of each module of the microreactor to T. S PID control is initiated, and the temperature of each module in the microreactor stabilizes at T under the action of the flexible heater and / or Peltier element. S Record the input voltage V of the flexible heater at this time. in It is then switched to a constant input, and the temperature of each module of the microreactor is maintained at T using PID control of the Peltier element. S The reaction remains unchanged. Subsequently, reactant A is fed by two feed pumps at a volumetric flow rate V. A Reactant B is expressed at a volumetric flow rate V B Pumping water from the microreactor preheating / precooling module until the channel is completely filled and the reaction components reach stability, then shutting down both pumps. Wait for all temperature and voltage signals to stabilize and continue monitoring for 10-15 minutes, recording the stable thermoelectric voltage measured by the Seebeck element. Subsequently, a constant input voltage V1 is provided to the flexible heater I corresponding to each module of the microreactor, continuously monitored for 10-15 minutes, recording the current value of each flexible heater I under stable conditions, and obtaining the input power of each flexible heater I using the power calculation formula P=VI. Simultaneously, the stable thermoelectric voltage at this point is recorded. This process is repeated, gradually increasing the input voltage of the flexible heater I to V1. N Record the corresponding current values, calculate the input power of each flexible heater, and record the corresponding thermoelectric voltage. Based on the input power P of the flexible heater... i (i = pre, r1, r2…rn, quen) and the corresponding thermoelectric voltage U i The data was used to construct P values ​​for each module of the microreactor through polynomial fitting. i =f(U i Functional relationship.

[0031] Step 2: Reaction Calorimetry. After calibration, disconnect the voltage input to flexible heater one, and maintain the input voltage V of flexible heater two. in The system remains unchanged, waiting for all temperature and voltage signals to stabilize. Then, reactant A is fed through two feed pumps at a volumetric flow rate V. A Reactant B is expressed at a volumetric flow rate V B Pumped from the microreactor preheating / precooling module, the materials are preheated / precooled, and the temperatures T of the two streams after preheating / precooling are recorded. in , A T in , BThe two materials are mixed and reacted in the reaction module, and then flow into the quenching module. The material temperature T at the outlet of the reaction module is recorded. out In the quenching module, the third feed pump delivers the quenching reagent C at a volumetric flow rate V. C The reaction was rapidly quenched by pumping, stopping the reaction process. Finally, the reactant stream exited the microreactor and entered a product collection device for further analysis, and the conversion rate (X) was determined. During the experiment, the temperature of all modules in the microreactor remained stable at T under Peltier element PID control mode. S During the experiment, the thermoelectric voltage U under the reaction state can be calculated using the polynomial P = f(U) obtained from the calibration. pre U r1 U r2 …U rn U quen This is converted into the heat release power of each module of the microreactor, thereby achieving high-resolution real-time calorimetry for continuous flow reaction processes.

[0032] Step 3: Enthalpy Calculation. The heat balance formula for a continuous flow reactive calorimetry system during the reaction is as follows:

[0033] Q r =Q Conp -(Q tra +Q loss )

[0034] Among them, Q r For the reaction heat flux, Q conv Q represents the convective heat flow carried into the system by reactants and carried out by products. tra Q is the heat flow neutralized by thermal conduction. loss This refers to the heat loss flow of the system.

[0035] Among them, the convective heat flow Q conv It consists of three parts and can be calculated using the following formula:

[0036] Q Conv =Q in,A +Q in,B -Q out

[0037] Q in,A =c p，A ρ A V A (T in,A -T S )

[0038] Q in,B =c p,B ρ B V B (T in,B -T S )

[0039] Q out =c p,out ρ out V out (T out -T S )

[0040] Among them, Q in，A With Q in，B Q represents the heat flow introduced into the system by reactants A and B. out To remove the heat flow from the system by the product, c p，A c p，B With c p，out The specific heat capacities of reactants A, B, and products are V, respectively. out The volumetric flow rate of the product.

[0041] Q tra With Q loss The sum can be obtained through calibration calculation, that is:

[0042]

[0043] Reaction heat flow Q r This can be expressed as the following formula:

[0044] Q r =V A / B C A / B ΔH r X

[0045] Among them, V A / B Let C be the volumetric flow rate of the reactant that limits the reaction between substances A and B. A / B Given the initial concentration of the above substances, ΔH r Let X be the enthalpy of the reaction and X be the conversion rate. Finally, substituting the data into the above equation yields the enthalpy of the reaction ΔH. r .

[0046] The calorimetric method described above can maintain a constant temperature in the microreactor during the calorimetric process, has high heat exchange efficiency, and can be used simultaneously for reaction kinetic studies.

[0047] The calorimetric method described above is quick and efficient.

[0048] The beneficial effects of this invention are:

[0049] The present invention provides a high spatial resolution continuous flow reaction calorimetry system and calorimetry method applicable to various types of exothermic reactions, such as liquid-liquid or gas-gas homogeneous, liquid-liquid heterogeneous, and gas-liquid heterogeneous reactions.

[0050] This invention enables high-resolution real-time calorimetry and determination of reaction enthalpy at different parts of a continuous flow reactor at different reaction temperatures, and the resolution can be adjusted by designing the reaction channel.

[0051] The system of this invention has a built-in heater and cooler, eliminating the need for an external source for temperature regulation, and also has a built-in calibrator, eliminating the need for external calibration.

[0052] This invention maintains a constant temperature in the microreactor during the calorimetric process, exhibiting high heat exchange efficiency and allowing for simultaneous application in reaction kinetics studies. This invention can achieve calorimetric analysis of ultrafast (<10s) strongly exothermic reactions.

[0053] The present invention has a short reaction time and high efficiency for calorimetry, and the microreactor used has a small liquid holding capacity, which can reduce reagent consumption and improve calorimetric safety.

[0054] This invention enables high-resolution real-time calorimetry and enthalpy measurement of different parts of a continuous flow reactor at different temperatures through a built-in temperature control unit. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of a high spatial resolution continuous flow reactive calorimetric system.

[0056] Figure 2 This is a schematic diagram of the connection structure of a high spatial resolution continuous flow reactive calorimetric system.

[0057] The attached diagram is labeled as follows: 1. Microreactor; 2. Flexible heater one; 3. Flexible heater two; 4. Seebeck element; 5. Peltier element; 6. Thermostatic block; 7. Circulating fluid inlet; 8. Circulating fluid outlet; 101. Feed pump; 102. Preheating / precooling module; 103. Temperature sensor; 104. Reaction module; 105. Quenching module; 106. Central control unit; 107. Control computer. Detailed Implementation

[0058] To better understand the technical solution of the present invention, the specific implementation of the present invention will be further described below with reference to the accompanying drawings.

[0059] See attached document Figure 1 , 2A high spatial resolution continuous flow reaction calorimetry system includes a microreactor 1, flexible heaters, Seebeck elements 4, Peltier elements 5, and a thermostatic block 6. The components are connected in direct contact, and thermal conductivity between components can be enhanced by applying thermal grease to their surfaces. The flexible heaters are connected to a DC power supply and then to a central control unit 106. The output voltage of the DC power supply is controlled by a control computer 107 to adjust the heating capacity. A second flexible heater 3 above the microreactor 1 is used to regulate the reaction temperature, while a first flexible heater 2 below is used for calibration. The Seebeck element 4 converts the temperature difference between the upper and lower surfaces into an electrical signal, which is monitored in real time by connecting to the central control unit 106. The Peltier element 5, connected to the central control unit 106, combines temperature measurement by a temperature sensor 103 with a PID control algorithm to cool the microreactor 1. The cooling capacity is adjusted by dynamically regulating the input voltage of the Peltier element 5 to maintain a constant temperature in the microreactor 1. The thermostatic block 6 is connected to a circulating oil bath to remove heat generated on the upper surface of the Peltier element 5. The calorimetry system is covered with insulation material to reduce heat exchange with the outside environment.

[0060] The microreactor 1 adopts a modular design, consisting of three parts: a preheating / precooling module 102, a reaction module 104, and a quenching module 105. The preheating / precooling module 102 is used to heat or cool the reactants before the chemical reaction begins, reaching the target reaction temperature. The reaction module 104 is used to carry out the chemical reaction. The quenching module 105 is used to quench the reaction and stop it from proceeding. Only necessary pipe connections are maintained between all modules to reduce heat conduction between different modules. The channel configuration in each module can be designed independently, and the liquid holdup of the module can be adjusted independently; the smaller the liquid holdup, the higher the resolution of heat flow identification. The number of modules can be increased or decreased according to the actual needs of the reaction.

[0061] The upper and lower surfaces of microreactor 1 need to undergo surface treatment to reduce roughness. The material of microreactor 1 can be stainless steel, Hastelloy, silicon carbide, ceramics, or other media with good thermal conductivity and corrosion resistance. The reactor can withstand pressures of 4 MPa or higher.

[0062] The microreactor 1 is a planar reactor with an internal channel size of <1mm.

[0063] The size and number of the flexible heater, Seebeck element 4, and Peltier element 5 must correspond to the number of modules in the microreactor 1 in order to enable individual monitoring and control of each module.

[0064] The preheating / precooling module 102 of the microreactor 1 is connected to two feed pumps at its front end. These feed pumps have volumetric metering capabilities and are used for quantitative delivery of the reaction medium. The quenching module 105 of the microreactor is connected to a feed pump on its side for quantitative delivery of the reaction quenching medium. The outlet of the quenching module 105 can be connected to a product collection device for analyzing the reaction products and determining the conversion rate of the reaction medium. Temperature sensors 103 are installed inside each module, between the preheating / precooling module 102 and the reaction module 104, and between the reaction module 104 and the quenching module 105. These temperature sensors 103 are connected to the central control unit 106 for monitoring the temperature at each location.

[0065] This system regulates the reaction temperature through the synergistic effect of a flexible heater and a Peltier element 5. The adjustable range depends on the performance of both elements, and this temperature range can be further extended using a circulating oil bath. During the experiment, the central control unit 106 and the control computer 107 monitor and control signals such as temperature and voltage. All data monitored by this system are automatically saved to the control computer 107 for subsequent analysis.

[0066] The flexible heater can be of different types, such as a polyimide film heater, a silicone heater, or a polyester heater.

[0067] Both the Seebeck element 4 and the Peltier element 5 are thermoelectric elements. The Seebeck element 4 converts the thermal signal into an electrical signal, and the Peltier element 5 converts the electrical signal into a thermal signal. When the Peltier element 5 is energized, its cold side is in contact with the Seebeck element 4, and its hot side is in contact with the thermostatic block 6.

[0068] The constant temperature block 6 is a heat exchange device that is hollow inside or has a specific configuration.

[0069] The calorimetric system described herein is applicable to various types of exothermic reactions, including homogeneous liquid-liquid or gas-gas reactions, heterogeneous liquid-liquid reactions, and heterogeneous gas-liquid reactions.

[0070] The calorimetric system described above can perform high-resolution real-time calorimetry on different parts of a continuous flow reactor at different reaction temperatures, and the resolution can be adjusted by designing the reaction channels.

[0071] The calorimetric system has a built-in heater and cooler, eliminating the need for an external source for temperature regulation, and it also has a built-in calibrator, eliminating the need for external calibration.

[0072] The calorimetric system described above can realize the reaction calorimetry of ultra-fast (<10s) strongly exothermic reactions.

[0073] The calorimetric system has a small liquid holding capacity, which can reduce reagent consumption and improve calorimetric safety.

[0074] This invention also provides a calorimetric method for a high spatial resolution continuous flow reaction calorimetric system, comprising the following three steps: The specific steps are as follows:

[0075] Step 1: Calibration. Set the circulating oil bath temperature to T0. After the temperature stabilizes, set the temperature of each module in microreactor 1 to T0 using the control computer 107. S PID control is initiated, and the temperature of each module in microreactor 1 is stabilized at T under the action of flexible heater 2 3 and / or Peltier element 5. S Record the input voltage V of flexible heater 23 at this time. in It is then switched to a constant input, and the temperature of each module of the microreactor 1 is maintained at T by PID control of the Peltier element 5. S The reaction remains unchanged. Subsequently, reactant A is fed by two feed pumps 101 at a volumetric flow rate V. A Reactant B is expressed at a volumetric flow rate V B Pumping into the preheating / precooling module 102 of microreactor 1 until the channel is completely filled and the reaction components reach stability, then turning off both pumps. Wait for all temperature and voltage signals to stabilize and continue monitoring for 10-15 minutes, recording the stable thermoelectric voltage U measured by Seebeck element 4. pre，0 U r1，0 U r2，0 …U rn，0 U quen，0 Subsequently, a constant input voltage V1 was provided to the flexible heaters 2 corresponding to each module of the microreactor 1, and the current value I of each flexible heater 2 was recorded under steady-state conditions for 10-15 minutes. pre，1 I r1，1 I r2，1 …I rn，1 I quen，1 The input power P of each flexible heater-2 is obtained according to the power calculation formula P = VI. pre，1 P r1，1 P r2，1 …P rn，1 P quen，1 Meanwhile, record the stable thermoelectric voltage at this time as U. pre，1 U r1，1 U r2，1 …U rn，1 U quen，1 Similarly, gradually increase the input voltage of the flexible heater-2 to V. N Record the corresponding current value I pre，N I r1，1 I r2，N …I rn，N I quen，N The input power P of each flexible heater-2 was calculated. pre，N Pr1，N P r2，N …P rn，N P quen，N Record the corresponding thermoelectric voltage as U. pre，N U r1，N U r2，N …U rn，N U quen，N Based on the flexible heater-2 input power P i (i = pre, r1, r2…rn, quen) and the corresponding thermoelectric voltage U i The data were used to construct P values ​​for each module of microreactor 1 through polynomial fitting. i =f(U i Functional relationship.

[0076] Step 2: Reaction Calorimetry. After calibration, disconnect the voltage input of flexible heater 2, and maintain the input voltage V of flexible heater 3. in The system remains unchanged, waiting for all temperature and voltage signals to stabilize. Then, reactant A is fed by two feed pumps 101 at a volumetric flow rate V. A Reactant B is expressed at a volumetric flow rate V B The material is pumped into the preheating / precooling module 102 of the microreactor 1 for preheating / precooling, and the temperatures T of the two materials after preheating / precooling are recorded. in，A T in，B The two materials are mixed and reacted in reaction module 104, and then flow into quenching module 105. The material temperature T at the outlet of the reaction module is recorded. out In the quenching module 105, the third feed pump 101 delivers the quenching reagent C at a volumetric flow rate V. C The reaction was rapidly quenched by pumping, stopping the reaction process. Finally, the reactant stream exited microreactor 1 and entered a product collection device for further analysis, and the conversion rate was determined to be X. During the experiment, the temperature of all modules in microreactor 1 remained stable at T under Peltier element PID control mode. S During the experiment, the thermoelectric voltage U under the reaction state can be calculated using the polynomial P = f(U) obtained from the calibration. pre U r1 U r2 …U rn U quen This is converted into the heat release power of each module of microreactor 1, thereby achieving high-resolution real-time calorimetry for different parts of the continuous flow reaction process.

[0077] Step 3: Enthalpy Calculation. The heat balance formula for a continuous flow reactive calorimetry system during the reaction is as follows:

[0078] Q r =Q conv -(Qtra +Q loss )

[0079] Among them, Q r Q represents the heat flux of the reaction, measured in W. conv Q represents the convective heat flux carried into and out of the system by reactants, expressed in W. tra Q is the heat flux neutralized by thermal conduction, measured in W; loss This represents the heat loss flow of the system, expressed in W.

[0080] Among them, the convective heat flow Q conv It consists of three parts and can be calculated using the following formula:

[0081] Q conv =Q in，A +Q in，B -Q out

[0082] Q in，A =c p，A ρ A V A (T in，A -T S )

[0083] Q in，B =c p，B ρ B V B (T in，B -T S )

[0084] Q out =c p，out ρ out V out (T out -T S )

[0085] Among them, Q in，A With Q in，B Q represents the heat flow introduced into the system by reactants A and B. out To remove the heat flow from the system by the product, c p，A c p，B With c p，out These are the specific heat capacities of reactants A and B, and the product, respectively, in J / (g·K) and V. out The volumetric flow rate of the product is expressed in mL / min.

[0086] Q tra With Q loss The sum can be obtained through calibration calculation, that is:

[0087]

[0088] Reaction heat flow Q r This can be expressed as the following formula:

[0089] Q r =V A / B C A / B ΔH r X

[0090] Among them, V A / B The volumetric flow rate of the reactant that limits the reaction between substances A and B, expressed in mL / min; C A / B The initial concentration of the above substances is expressed in mol / L; ΔH r Let X be the enthalpy of reaction, expressed in kJ / mol; X be the conversion rate. Finally, substituting the data into the above equation yields the enthalpy of reaction ΔH. r .

[0091] The described calorimetric method maintains a constant temperature in the microreactor throughout the calorimetric process, exhibits high heat exchange efficiency, and can be simultaneously used for reaction kinetic studies. This method is also time-efficient.

[0092] Example 1

[0093] This invention provides a high spatial resolution continuous flow reactive calorimetry system, see attached figure. Figure 1 The system consists of a microreactor 1, flexible heater 2, flexible heater 3, Seebeck element 4, Peltier element 5, and a thermostatic block 6. All components are connected via direct contact, with thermal grease applied to the contact surfaces to enhance heat conduction. Flexible heaters 2 and 3 are connected to a DC power supply and then to a central control unit 106. The output voltage of the DC power supply is controlled by a computer 107 to adjust the heating capacity. Flexible heater 3 above the microreactor 1 is used to regulate the reaction temperature, while flexible heater 2 below is used for calibration. The Seebeck element 4 converts the temperature difference between its upper and lower surfaces into an electrical signal, which is monitored in real-time by the central control unit 106. The Peltier element 5, connected to the central control unit 106, combines temperature sensor measurement and a PID control algorithm to cool the microreactor 1. The cooling capacity is adjusted by dynamically regulating the input voltage of the Peltier element to maintain a constant temperature in the microreactor 1. The thermostatic block 6 is connected to a circulating oil bath to remove heat generated on the upper surface of the Peltier element. The entire calorimetric system is covered with insulation material to reduce heat exchange with the external environment.

[0094] The microreactor 1 adopts a modular design, consisting of a preheating / precooling module 102, a reaction module 104, and a quenching module 105. The preheating / precooling module 102 heats or cools the reactants before the chemical reaction begins, reaching the target reaction temperature. The reaction module 104 is used to carry out the chemical reaction. The quenching module 105 is used to quench the reaction and stop it. Only necessary piping connections are maintained between all modules to reduce heat transfer between them. The channel configuration in each module can be designed independently, and the liquid holdup of the module can be adjusted. The smaller the liquid holdup, the higher the resolution of heat flow identification. The number of modules can be increased or decreased according to actual reaction requirements. The microreactor 1 can be made of materials with good thermal conductivity and corrosion resistance, such as stainless steel, Hastelloy, silicon carbide, or ceramics, and the reactor can withstand pressures above 4 MPa. The size and number of flexible heater 1 (2), flexible heater 2 (3), Seebeck element (4), and Peltier element (5) must correspond to the number of modules in the microreactor 1 to achieve individual monitoring and control of each module.

[0095] The preheating / precooling module 102 of microreactor 1 is connected to two feed pumps at its front end. These feed pumps have volumetric metering capabilities for quantitative delivery of the reaction medium. The quenching module 105 of microreactor 1 is connected to a feed pump on its side for quantitative delivery of the reaction quenching medium. The outlet of the quenching module 105 of microreactor 1 can be connected to a product collection device for analyzing reaction products and determining the conversion rate of the reaction medium. Temperature sensors 103 are installed inside each module, between the preheating / precooling module 102 and the reaction module 104, and between the reaction module 104 and the quenching module 105. These temperature sensors 103 are connected to the central control unit 106 for monitoring the temperature at each location.

[0096] This system regulates the reaction temperature through the synergistic effect of the flexible heater 3 and the Peltier element 4. The adjustable range depends on the performance of the two elements, and this temperature range can be further extended by using a circulating oil bath. During the experiment, the temperature, voltage, and other signals are monitored and controlled by the central control unit 106 and the control computer 107. All data monitored by this system are automatically saved to the control computer 107 and can be used for subsequent analysis.

[0097] Example 2

[0098] This invention also provides a calorimetric method for a high spatial resolution continuous flow reaction calorimetric system, according to the appendix. Figure 1 Assemble the continuous flow reactive calorimeter system and follow the instructions. Figure 2 Establish the connection. Based on the above experimental platform, the steps of this embodiment are as follows:

[0099] First, calibration is performed. The circulating oil bath temperature is set to T0. After the temperature stabilizes, the temperature of each module in microreactor 1 is set to T using the control computer 107. SPID control is initiated, and the temperature of each module in microreactor 1 is stabilized at T under the action of flexible heater 2 3 and / or Peltier element 5. S Record the input voltage V of flexible heater 23 at this time. in It is then switched to a constant input, and the temperature of each module of the microreactor 1 is maintained at T by PID control of the Peltier element 5. S The values ​​remain unchanged. Subsequently, the volumetric flow rates of the two feed pumps 101 are set to V. A With V B Then, start the pumps to pump reactant A and reactant B into the preheating / precooling module 102 of microreactor 1 until the channel is completely filled and the reaction components reach stability. Then, turn off both pumps. Wait for all temperature and voltage signals to stabilize and continue monitoring for 10-15 minutes. Record the stable thermoelectric voltage U measured by Seebeck element 4. pre，0 U r1，0 U r2，0 …U rn，0 U quen，0 Subsequently, a constant input voltage V1 was provided to the flexible heaters 2 corresponding to each module of the microreactor 1, and the current value I of each flexible heater 2 was recorded under steady-state conditions for 10-15 minutes. pre，1 I r1，1 I r2，1 …I rn，1 I quen，1 The input power P of each flexible heater-2 is obtained according to the power calculation formula P = VI. pre，1 P r1，1 P r2，1 …P rn，1 P quen，1 Meanwhile, record the stable thermoelectric voltage at this time as U. pre，1 U r1，1 U r2，1 …U rn，1 U quen，1 Similarly, gradually increase the input voltage of the flexible heater-2 to V. N Record the corresponding current value I pre，N I r1，1 I r2，N …I rn，N I quen，N The input power P of each flexible heater-2 was calculated. pre，N P r1，N P r2，N …P rn，N P quen，N Record the corresponding thermoelectric voltage as U. pre，N U r1，N U r2，N …U rn，N Uquen，N Based on the flexible heater-2 input power P i (i = pre, r1, r2…rn, quen) and the corresponding thermoelectric voltage U i The data were used to construct P values ​​for each module of microreactor 1 through polynomial fitting. i =f(U i Functional relationship.

[0100] Then, calorimetry of the reaction is performed. The voltage input to flexible heater 2 is disconnected, while the input voltage V of flexible heater 3 is maintained. in The system remains unchanged, waiting for all temperature and voltage signals to stabilize. Then, reactant A is fed by two feed pumps 101 at a volumetric flow rate V. A Reactant B is expressed at a volumetric flow rate V B Pumped into the preheating / precooling module 102 of microreactor 1 for preheating / precooling, and the temperatures T of the two materials after preheating / precooling are recorded. in，A T in，B The two materials are mixed and reacted in reaction module 104, and then flow into quenching module 105. The material temperature T at the outlet of reaction module 104 is recorded. out In the quenching module 105, the third feed pump 101 delivers the quenching reagent C at a volumetric flow rate V. C The reaction is rapidly quenched by pumping, stopping the reaction process. Finally, the reactant stream exits microreactor 1 and enters a product collection device for further analysis, and the conversion rate is determined to be X.

[0101] Finally, the enthalpy of reaction is calculated. The heat balance equation for the continuous flow reactive calorimetry system during the reaction is shown below:

[0102] Q r =Q conv -(Q tra +Q loss )

[0103] In the formula, Q r For the reaction heat flux, Q conv Q represents the convective heat flow carried into the system by reactants and carried out by products. tra Q is the heat flow neutralized by thermal conduction. loss This refers to the heat loss flow of the system.

[0104] Among them, the convective heat flow Q conv It can be calculated using the following formula:

[0105] Q conv =Q in，A +Q in，B -Q out

[0106] Q in，A=c p，A ρ A V A (T in，A -T S )

[0107] Q in，B =c p，B ρ B V B (T in，B -T S )

[0108] Q out =c p，out ρ out V out (T out -T S )

[0109] In the formula, Q in，A With Q in，B Q represents the heat flow introduced into the system by reactants A and B. out To remove the heat flow from the system by the product, c p，A c p，B With c p，out The specific heat capacities of reactants A, B, and products are V, respectively. out The volumetric flow rate of the product.

[0110] Q tra With Q loss The sum can be obtained through calibration calculation, that is:

[0111]

[0112] Reaction heat flow Q r This can be expressed as the following formula:

[0113] Q r =V A / B C A / B ΔH r X

[0114] In the formula, V A / B Let C be the volumetric flow rate of the reactant that limits the reaction between substances A and B. A / B Given the initial concentration of the above substances, ΔH r Let X be the enthalpy of the reaction and X be the conversion rate. Finally, substituting the data into the above equation yields the enthalpy of the reaction ΔH. r .

[0115] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A calorimetric method for a high spatial resolution continuous flow reactive calorimetric system, characterized in that, A high spatial resolution continuous flow reaction calorimetry system includes a microreactor, a flexible heater, a Seebeck element, a Peltier element, and a thermostat. The components are connected by direct contact, and the heat conduction between the components can be enhanced by applying thermal grease to the surface; The flexible heaters are connected to a DC power supply and then to a central control unit. The output voltage of the DC power supply is controlled by a computer to adjust the heating capacity. The second flexible heater above the microreactor is used to regulate the reaction temperature, while the first flexible heater below is used for calibration. Seebeck elements convert the temperature difference between the upper and lower surfaces into electrical signals, which are then monitored in real time by connecting to the central control unit. The Peltier element is connected to the central control unit. Combined with temperature sensor measurement and PID control algorithm, it cools the microreactor. The cooling capacity is adjusted by dynamically adjusting the input voltage of the Peltier element to maintain a constant temperature in the microreactor. The thermostatic block is connected to the circulating oil bath and is used to remove the heat generated on the upper surface of the Peltier element; The heating system is covered with insulation material to reduce heat exchange with the outside environment; The calorimetric method for a high spatial resolution continuous flow reaction calorimetric system comprises the following steps: Step 1: Calibration. Set the circulating oil bath temperature to T0. After the temperature stabilizes, set the temperature of each module of the microreactor to T. S PID control is initiated, and the temperature of each module in the microreactor stabilizes at T under the action of the flexible heater and / or Peltier element. S Record the input voltage V of the flexible heater at this time. in It is then switched to a constant input, and the temperature of each module of the microreactor is maintained at T using PID control of the Peltier element. S The process remains unchanged; subsequently, reactant A is fed by two feed pumps at a volumetric flow rate V. A Reactant B is expressed at a volumetric flow rate V B Pumping from the microreactor preheating / precooling module until the channel is completely filled and the reaction components reach stability, then turning off both pumps; waiting for all temperature and voltage signals to return to stability and continuing monitoring for 10-15 minutes, recording the stable thermoelectric voltage measured by the Seebeck element; subsequently, providing a constant input voltage V1 to the flexible heater I corresponding to each module of the microreactor, continuously monitoring for 10-15 minutes, recording the current value of each flexible heater I under stable conditions, and obtaining the input power of each flexible heater I according to the power calculation formula P=VI, while simultaneously recording the stable thermoelectric voltage at this time; By analogy, gradually increase the input voltage of the flexible heater to V. N Record the corresponding current values, calculate the input power of each flexible heater, and record the corresponding thermoelectric voltage; based on the input power P of the flexible heater, i (i=pre, r1, r2…rn, quen) and the corresponding thermoelectric voltage U i The data was used to construct P values ​​for each module of the microreactor through polynomial fitting. i =f(U i Functional relationship; Step 2: After the reaction calorimetry calibration is completed, disconnect the voltage input of flexible heater one, and maintain the input voltage V of flexible heater two. in Remain unchanged and wait for all temperature and voltage signals to stabilize; then, use two feed pumps to deliver reactant A at a volumetric flow rate V. A Reactant B is expressed at a volumetric flow rate V B Pumped from the microreactor preheating / precooling module, the materials are preheated / precooled, and the temperatures T of the two streams after preheating / precooling are recorded. in，A T in，B The two materials are mixed and reacted in the reaction module, and then flow into the quenching module. The material temperature T at the outlet of the reaction module is recorded. out In the quenching module, the third feed pump delivers the quenching reagent C at a volumetric flow rate V. C The reaction is rapidly quenched by pumping in the reactants, stopping the reaction process. Finally, the reactants flow out of the microreactor and enter the product collection device for further analysis, and the conversion rate is determined to be X. During the experiment, the temperature of all modules in the microreactor remained stable at T under Peltier element PID control mode. S During the experiment, the thermoelectric voltage U under the reaction state can be calculated using the polynomial P=f(U) obtained from the calibration. pre U r1 U r2 …U rn U quen This is converted into the heat release power of each module of the microreactor, thereby achieving high-resolution real-time calorimetry for continuous flow reaction processes. Step 3: Calculation of reaction enthalpy. The heat balance formula for the continuous flow reactive calorimetry system during the reaction is as follows: ; Among them, Q r For the reaction heat flux, Q conv Q represents the convective heat flow carried into the system by reactants and carried out by products. tra Q is the heat flow neutralized by heat conduction. loss This refers to the heat loss flow caused by heat dissipation in the system. Among them, the convective heat flow Q conv It consists of three parts and can be calculated using the following formula: ; ; ; ; Among them, Q in，A With Q in，B Q represents the heat flow introduced into the system by reactants A and B. out To remove the heat flow from the system by the product, c p，A c p，B With c p，out The specific heat capacities of reactants A, B, and products are V, respectively. out The volumetric flow rate of the product, Q tra With Q loss The sum can be obtained through calibration calculation, that is: (i=r1,r2…rn); Reaction heat flow Q r This can be expressed as the following formula: ; Among them, V A / B Let C be the volumetric flow rate of the reactant that limits the reaction between substances A and B. A / B Given the initial concentration of the above substances, ΔH r Let X be the enthalpy of the reaction and X be the conversion rate; finally, substituting the data into the above formula will yield the enthalpy of the reaction ΔH. r .

2. The calorimetric method for a high spatial resolution continuous flow reaction calorimetry system according to claim 1, characterized in that, The microreactor adopts a modular design, consisting of three parts: a preheating / precooling module, a reaction module, and a quenching module. The preheating / precooling module is used to heat or cool the reactants before the chemical reaction begins to reach the target reaction temperature. The reaction module is used to carry out the chemical reaction. The quenching module is used to quench the reaction and stop it from proceeding. Only necessary pipe connections are retained between all modules to reduce heat conduction between different modules. The channel configuration in each module can be designed by the user, and the liquid holding capacity of the module can be adjusted by the user. The smaller the liquid holding capacity, the higher the resolution of heat flow identification. The number of modules can be increased or decreased according to the actual needs of the reaction.

3. The calorimetric method for a high spatial resolution continuous flow reactive calorimetric system according to claim 1, characterized in that, The upper and lower surfaces of the microreactor need to undergo surface treatment to reduce roughness; the microreactor material can be stainless steel, Hastelloy, silicon carbide or ceramic, with good thermal conductivity and corrosion resistance, and the microreactor can withstand pressure above 4 MPa.

4. A calorimetric method for a high spatial resolution continuous flow reactive calorimetric system according to claim 1 or 3, characterized in that, The microreactor is a planar reactor with an internal channel size of <1 mm.

5. The calorimetric method for a high spatial resolution continuous flow reactive calorimetric system according to claim 1, characterized in that, The size and number of flexible heaters, Seebeck elements, and Peltier elements need to correspond to the number of modules in the microreactor in order to enable individual monitoring and control of each module.

6. The calorimetric method for a high spatial resolution continuous flow reactive calorimetric system according to claim 1, characterized in that, The preheating / precooling module of the microreactor is connected to two feed pumps at the front end. The feed pumps have a volume metering function and are used for quantitative delivery of the reaction medium. The quenching module of the microreactor is connected to a feed pump on the side and is used for quantitative delivery of the reaction quenching medium. The outlet of the quenching module of the microreactor can be connected to a product collection device for analysis of reaction products and determination of the conversion rate of the reaction medium. Temperature sensors are installed inside each module, between the preheating / precooling module and the reaction module, and between the reaction module and the quenching module. The temperature sensors are connected to the central control unit to monitor the temperature of each part.

7. The calorimetric method for a high spatial resolution continuous flow reactive calorimetric system according to claim 1, characterized in that, This system regulates the reaction temperature through the synergistic effect of a flexible heater and a Peltier element. The adjustable range depends on the performance of the two elements and can be further extended by using a circulating oil bath. During the experiment, the temperature and voltage signals are monitored and controlled by a central control unit and a control computer. All data monitored by this system are automatically saved to the control computer for subsequent analysis.

8. The calorimetric method for a high spatial resolution continuous flow reactive calorimetric system according to claim 1, characterized in that, The flexible heater is a polyimide film heater, a silicone heater, or a polyester heater.

9. The calorimetric method for a high spatial resolution continuous flow reactive calorimetric system according to claim 1, characterized in that, Both the Seebeck element and the Peltier element are thermoelectric elements. The Seebeck element converts the thermal signal into an electrical signal, and the Peltier element converts the electrical signal into a thermal signal. When the Peltier element is energized, the cold side is in contact with the Seebeck element at the bottom, and the hot side is in contact with the thermostatic block at the top. The thermostatic block is a heat exchange device that is hollow inside or has a specific configuration.

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