Device and method for dynamic tracking of reference calorimetry at microscale

Abstract

The application provides a device and method for dynamically tracking reference continuous calorimetry under microscale, and relates to the technical field of reaction heat measurement. The device comprises: a material input and output system; the material input and output system is connected with a microscale continuous reaction system; the material input and output system is controlled by a central control and data acquisition system and injects materials into the microscale continuous reaction system; the microscale continuous reaction system; a microchannel reaction chip B in the microscale continuous reaction system is used for generating material reaction; a microchannel reference chip A in the microscale continuous reaction system is used for simulating the heat absorption and release process of the reaction in the microchannel reaction chip B and indirectly obtaining the heat absorption and release amount in the microchannel reaction chip B; a central control and data acquisition system; the central control and data acquisition system collects the heat absorption and release amount and calculates the reaction heat according to the heat absorption and release amount. The whole calorimetry process is simple and fast, and the accuracy of calorimetry can be ensured without repeated correction.

Description

Technical Field

[0001] This invention relates to the field of reaction heat measurement technology, and more particularly to a device and method for dynamically tracking a reference continuous calorimeter at a microscale. Background Technology

[0002] Measuring calorimetric data for chemical reactions is crucial for reaction safety and reactor design, operation, and scale-up. Calorimetry provides this data. Currently, batch calorimetry is widely used. In recent years, continuously operating microreactors have been increasingly used in chemical production and process development. Microreactor technology allows for precise control of demanding process conditions. In microreactors, the smaller reaction system reduces waste, makes operation safer, and lowers energy consumption. Measuring calorimetric data under continuous flow conditions yields higher yields, conversion rates, and selectivity, while also facilitating process automation. Due to the small volume and large surface area of ​​microchannel reactors, they exhibit high heat transfer efficiency under steady-state conditions, especially for rapid, strongly exothermic reactions. Calorimetric data from traditional batch calorimeters cannot be fully applied to continuous flow microreactors. Therefore, calorimetric data under continuous flow conditions offers significant advantages.

[0003] Among existing technologies for measuring the heat of reaction, patent CN114199937A discloses a calorimetric testing method and apparatus for ultra-low temperature reactions, which can realize ultra-low temperature isothermal calorimetric testing of semi-batch reactions. However, this invention cannot realize the calorimetry of continuous flow reactions. Patent CN109459161A discloses a calorimetric testing method and apparatus for tubular reactions, realizing the calorimetric testing of exothermic and endothermic tubular reactions, but its calibration process is complex and calculations are cumbersome. Patent CN110988035A discloses a method and apparatus for testing the heat of reaction in continuous flow reactions using reference calorimetry, realizing the testing of the heat of reaction in continuous flow reactions, but its apparatus structure is complex, the calorimetric process is too time-consuming, and the calorimetric results still have a large error compared with the theoretical values. The typical literature on microscale continuous calorimetry, "Characterization of reaction enthalpy and kinetics in a microscale flow platform," uses microreactor chips to measure the reaction heat of acetic anhydride hydrolysis. The testing process is complex, requiring process correction before each calorimetry test, and cannot completely eliminate environmental influences, resulting in large errors. Summary of the Invention

[0004] To address the aforementioned technical problem of the difficulty in measuring the heat of reaction under continuous flow conditions, this invention provides a device and method for dynamically tracking a reference continuous calorimetry at a microscale. This invention primarily utilizes reference calorimetry to effectively eliminate the influence of the environment on the calorimetric process. By employing a dynamic tracking method, it accurately simulates the endothermic and exothermic processes of the reaction, rapidly and accurately measuring the heat of reaction. This solves the technical problem of the difficulty in measuring the heat of reaction under continuous flow conditions.

[0005] The technical means employed in this invention are as follows:

[0006] A device for dynamically tracking a reference continuous calorimetry at a microscale, comprising:

[0007] A material inlet / outlet system; the material inlet / outlet system is connected to a microscale continuous reaction system; the material inlet / outlet system is controlled by a central control and data acquisition system, and injects materials into the microscale continuous reaction system;

[0008] A microscale continuous reaction system; the microchannel reaction chip B in the microscale continuous reaction system is used to generate material reactions; the microchannel reference chip A in the microscale continuous reaction system is used to simulate the endothermic and exothermic processes of the reaction in the microchannel reaction chip B, and indirectly obtain the endothermic and exothermic heat in the microchannel reaction chip B.

[0009] A central control and data acquisition system; the central control and data acquisition system controls the operation of the entire device and collects data on the absorption and release of heat, and calculates the heat of reaction based on the absorption and release of heat.

[0010] Furthermore, the material inlet and outlet system includes an injection pump controller, a recovery tank A, a recovery tank B, and an injection pump. The injection pump controller is connected to the injection pump and controls the operating status and operating parameters of the injection pump.

[0011] The injection pumps include a first injection pump A, a second injection pump A, a quencher injection pump A, a first injection pump B, a second injection pump B, and a quencher injection pump B.

[0012] Furthermore, the first injection pump A is connected to the first inlet A on the microchannel reference chip A through the material preheating aluminum block and the material inlet / outlet interface A; the second injection pump A is connected to the second inlet A on the microchannel reference chip A through the material preheating aluminum block and the material inlet / outlet interface A; the quencher injection pump A is connected to the quencher inlet A on the microchannel reference chip A through the material preheating aluminum block and the material inlet / outlet interface A; and the recovery tank A is connected to the outlet A on the microchannel reference chip A through the material preheating aluminum block and the material inlet / outlet interface A.

[0013] The first injection pump B is connected to the first inlet B on the microchannel reference chip B via a material preheating aluminum block and a material inlet / outlet interface B. The second injection pump B is connected to the second inlet B on the microchannel reference chip B via a material preheating aluminum block and a material inlet / outlet interface B. The quencher injection pump B is connected to the quencher inlet B on the microchannel reference chip B via a material preheating aluminum block and a material inlet / outlet interface B. The recovery tank B is connected to the outlet B on the microchannel reference chip B via a material preheating aluminum block and a material inlet / outlet interface B.

[0014] Furthermore, the microscale continuous reaction system includes, from top to bottom, a viewing window, a microchannel chip, a heating film, a thermoelectric generator, and a temperature control device;

[0015] The microchannel chip includes a microchannel reference chip A and a microchannel reaction chip B arranged one behind the other. The inlet and outlet ports of the microchannel reference chip A and the microchannel reaction chip B are on the same side, and the channels of the microchannel reference chip A and the microchannel reaction chip B are on the same side.

[0016] The viewing window includes a material inlet / outlet viewing window and a channel viewing window. The material inlet / outlet viewing window is located above the inlet and outlet sides of the microchannel reference chip, and the channel viewing window is located above the channel side of the microchannel reference chip.

[0017] The heating film includes a heating film A that tracks exothermic reactions and a heating film B that tracks endothermic reactions. The heating film A that tracks exothermic reactions is disposed below the microchannel reference chip A, and the heating film B that tracks endothermic reactions is disposed below the microchannel reaction chip B.

[0018] The thermoelectric generator includes thermoelectric generator A and thermoelectric generator B. The thermoelectric generator A is disposed below the heating film A that tracks the exothermic reaction, and the thermoelectric generator B is disposed below the heating film B that tracks the endothermic reaction.

[0019] The constant temperature device includes a material preheating aluminum block and a reaction constant temperature aluminum block. The material preheating aluminum block is located below the inlet side of the microchannel chip, and the reaction constant temperature aluminum block is located below the channel outlet side of the microchannel chip. The material preheating aluminum block has two grooves on the inlet side corresponding to the microchannel reference chip A and the microchannel reaction chip B. Material inlet / outlet interface block A and material inlet / outlet interface block B are respectively arranged in the grooves. Through holes are formed on material inlet / outlet interface block A and material inlet / outlet interface block B to allow the pipeline of the injection pump to pass through.

[0020] Furthermore, the central control and data acquisition system includes a data acquisition card and a central control and data acquisition unit. The positive and negative terminals of the programmable DC power supply A are respectively connected to the heating film A that tracks the exothermic reaction, and the positive and negative terminals of the programmable DC power supply B are respectively connected to the heating film B that tracks the endothermic reaction. The data acquisition card is respectively connected to the thermoelectric generator A and the thermoelectric generator B. The central control and data acquisition unit is respectively connected to the programmable DC power supply A, the programmable DC power supply B, the data acquisition card, and the syringe pump controller.

[0021] The present invention also provides a method for dynamically tracking a reference continuous calorimeter at a microscale, implemented based on any of the above-mentioned devices for dynamically tracking a reference continuous calorimeter at a microscale, comprising the following steps:

[0022] Materials are simultaneously and continuously added to microchannel reference chip A and microchannel reaction chip B at the same flow rate. A single solvent is introduced into microchannel reference chip A through first injection pump A and second injection pump A, and the raw material for the test reaction is introduced into microchannel reaction chip B through first injection pump B and second injection pump B.

[0023] Quenching reaction is carried out by simultaneously adding quencher into microchannel reference chip A and microchannel reaction chip B at the same flow rate using quencher injection pump A and quencher injection pump B.

[0024] The voltage signal TEC of thermoelectric generator A and the voltage signal TER of thermoelectric generator B are acquired by the data acquisition card.

[0025] For exothermic reactions, the heating power of the heating film A is calculated by tracking the output power of the programmable DC power supply A, the heat of release Q of the reaction process is calculated by the residence time of the material in the reaction chip, and then the heat of reaction ΔH is calculated.

[0026] For endothermic reactions, the heating power of the heating film B is calculated by tracking the output power of the programmable DC power supply B, and the heat release Q of the reaction process is calculated by the residence time of the material in the reaction chip, and then the heat of reaction ΔH is calculated.

[0027] Furthermore, the temperatures of the material preheating aluminum block and the reaction isothermal aluminum block are set according to the reaction conditions, and the temperature is increased or decreased at a constant rate to the target temperature.

[0028] Furthermore, calculating the heating power of the thin film A by tracking the exothermic reaction includes the following steps:

[0029] When initially TEC > TER, an exothermic reaction occurs in microchannel reaction chip B. Changing the output voltage of programmable DC power supply A controls the heating power of the exothermic reaction-induced heating film A, simulating the exothermic process in microchannel reaction chip B. When the difference between TEC and TER is ΔV...i When the voltage approaches a certain value, the output voltage U of the programmable DC power supply A is obtained in real time. PC Thus, the heating power P of the thin film A, which is heated by the exothermic reaction, can be calculated. A ;

[0030] Initially, TEC < TER, indicating an endothermic reaction in the microchannel reaction chip B. The output voltage of the programmable DC power supply B is adjusted to control the heating power of the endothermic reaction-induced heating film B, compensating for the heat absorbed in the endothermic reaction within the microchannel reaction chip B. When the absolute value of the difference between TEC and TER is ΔV... i When the voltage approaches a certain value, the output voltage U of the programmable DC power supply B in real time is obtained. PR Calculate the heating power P of the film B by tracking the endothermic reaction. B .

[0031] Furthermore, the formula for calculating the heating power is as follows:

[0032]

[0033]

[0034] Among them, R A To track the resistance of the exothermic reaction heating thin film A, R B The resistance of the heated thin film B was measured to track the exothermic reaction.

[0035] Furthermore, the calculation steps for the heat of reaction ΔH are as follows:

[0036] The residence time t of the material in the reaction chip is calculated based on the volumetric flow rate set for the syringe pump.

[0037]

[0038] Where V is the volume of the reaction channel in microchannel reference chip A and microchannel reaction chip B, and q V1 The volumetric flow rate q of the material set for the first injection pump A and the first injection pump B V2 The volumetric flow rate of the material is set for the second injection pump A and the second injection pump B;

[0039] Calculate the heat absorbed and released during the reaction process Q based on the heating power of the heating film:

[0040] Q = P × t

[0041] Where, for an exothermic reaction, P = P A For an endothermic reaction, P = P B ;

[0042] Calculate the amount of substance n of the reactants:

[0043]

[0044] Where, q V Let c be the volumetric flow rate of a reactant, and c be the molar concentration of the reactant.

[0045] The heat of reaction, ΔH, is:

[0046]

[0047] Compared with the prior art, the present invention has the following advantages:

[0048] The device of this invention uses a microscale reaction chip, which has high mass and heat transfer efficiency, enabling single reactions with high reactant concentrations. At the same time, it greatly reduces the amount of material consumed in the calorimetric process. Compared with intermittent calorimetry, continuous calorimetry makes reaction conditions easier to control and improves process safety, enabling calorimetry for dangerous chemical reactions.

[0049] The device of this invention is equipped with a microchannel reference chip A and a microchannel reaction chip B. The two chips have identical structures and are injected simultaneously during the reaction process. The flow rate is strictly controlled to eliminate the influence of the environment on the calorimetric process. At the same time, the heat carried away by the material flow is deducted to obtain the true heat change of the reaction.

[0050] This invention uses a central control and data acquisition unit to control the injection pump, system temperature and DC power supply, while simultaneously performing online data acquisition and processing.

[0051] The entire calorimetric process of this invention is fast and accurate calorimetric data can be obtained without the need for correction before each calorimetric measurement.

[0052] The apparent results obtained by the dynamic tracking reference calorimetry test method of this invention can provide more practical and effective guidance for the engineering design, process safety and process optimization of energy conversion and transfer design. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a schematic diagram of the structure of the present invention.

[0055] Figure 2 This is an exploded view of the microscale continuous reaction system of the present invention.

[0056] Figure 3This is a schematic diagram of the microreaction chip structure of the present invention.

[0057] Figure 4 This is a schematic diagram of the constant temperature device of the present invention.

[0058] Figure 5 This is the dynamic tracking reference logic diagram for this invention.

[0059] Figure 6 The figure shows the experimental results of Embodiment 1 of the present invention.

[0060] Figure 7 The figure shows the experimental results of Embodiment 2 of the present invention.

[0061] Figure 8 The figure shows the experimental results of Embodiment 3 of the present invention.

[0062] In the diagram: 11. Material in / out viewing window; 12. Channel viewing window; 21. Microchannel reference chip A; 211. First feed inlet A; 212. Second feed inlet A; 213. Quencher feed inlet A; 214. Discharge outlet A; 22. Microchannel reaction chip B; 221. First feed inlet B; 222. Second feed inlet B; 223. Quencher feed inlet B; 224. Discharge outlet B; 31. Heating film A tracking exothermic reaction; 32. Heating film B tracking endothermic reaction; 33. Programmable DC power supply A; 34. Programmable DC power supply B; 4. Number According to the data acquisition card; 41. Thermoelectric generator A; 42. Thermoelectric generator B; 51. Material inlet / outlet interface block A; 52. Material inlet / outlet interface block B; 61. Material preheating aluminum block; 611. Constant temperature oil channel A; 62. Reaction constant temperature aluminum block; 621. Constant temperature oil channel B; 7. Injection pump controller; 71. First injection pump A; 72. Second injection pump A; 73. Quenching agent injection pump A; 74. Recovery tank A; 75. First injection pump B; 76. Second injection pump B; 77. Quenching agent injection pump B; 78. Recovery tank B; 8. Central control and data acquisition unit. Detailed Implementation

[0063] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0064] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0065] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0066] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0067] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0068] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0069] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0070] like Figure 1-4 As shown, the present invention provides a microscale dynamic tracking reference continuous calorimeter, including a material inlet / outlet system, a microscale continuous reaction system, and a central control and data acquisition system.

[0071] The material inlet / outlet system includes an injection pump controller 7, a first injection pump A71, a second injection pump A72, a quencher injection pump A73, a recovery tank A74, a first injection pump B75, a second injection pump B76, a quencher injection pump B77, and a recovery tank B78. The injection pump controller 7 controls the operating status and parameters of all injection pumps within the system. The first injection pump A71, the second injection pump A72, the quencher injection pump A73, and the recovery tank A74 are connected to the first inlet A211, the second inlet A212, the quencher inlet A213, and the outlet A214 on the microchannel reference chip A21 via a material preheating aluminum block 61 and a material inlet / outlet interface block A51, respectively. The first injection pump B75, the second injection pump B76, the quencher injection pump B77, and the recovery tank B78 are connected to the first inlet B221, the second inlet B222, the quencher inlet B223, and the outlet B224 on the microchannel reaction chip B22 via the material preheating block 61 and the material inlet / outlet interface block B52, respectively.

[0072] The microscale continuous reaction system includes a material inlet / outlet viewing window 11, a channel viewing window 12, a microchannel reference chip A21, a microchannel reaction chip B22, a tracking exothermic reaction heating film A31, a tracking endothermic reaction heating film B32, a thermoelectric generator A41, a thermoelectric generator B42, a material inlet / outlet interface block A51, a material inlet / outlet interface block B52, a material preheating aluminum block 61, and a reaction isothermal aluminum block 62. Figure 2 They are arranged sequentially and secured with screws around the perimeter. Among them, the microchannel reference chip A21 and the microchannel reaction chip B22 have identical structures, the heating film A31 that tracks exothermic reactions and the heating film B32 that tracks endothermic reactions are identical in model, and the thermoelectric generator A41 and the thermoelectric generator B42 are of the same model.

[0073] The central control and data acquisition system includes a programmable DC power supply A33, a programmable DC power supply B34, a data acquisition card 4, and a central control and data acquisition unit 8. The positive and negative electrodes of programmable DC power supply A33 are connected to the heating film A31 that tracks the exothermic reaction via wires. The positive and negative electrodes of programmable DC power supply B34 are connected to the heating film B32 that tracks the endothermic reaction via wires. The data acquisition card 4 is connected to thermoelectric generators A41 and B42. The central control and data acquisition unit 8 is connected to programmable DC power supply A33, programmable DC power supply B34, data acquisition card 4, and syringe pump controller 7 via communication lines.

[0074] This invention also provides a method for testing the heat of reaction of a continuous flow using a dynamic tracking reference continuous calorimeter at a microscale, comprising the following steps:

[0075] Microchannel reference chip A21 and microchannel reaction chip B22 have identical structures. Materials are continuously and simultaneously added to both microchannel reference chip A21 and microchannel reaction chip B22 at the same flow rate. The material introduced into microchannel reference chip A21 via first injection pump A71 and second injection pump A72 is a single solvent, while the material introduced into microchannel reaction chip B22 via first injection pump B75 and second injection pump B76 is the raw material for the test reaction. Quenchers are simultaneously added to microchannel reference chip A21 and microchannel reaction chip B22 via quencher injection pumps A73 and B77 at the same flow rate to quench the reaction promptly and ensure experimental safety. The reaction residence time is controlled by controlling the feeding rate. The voltage signals TEC and TER (in mV) of thermoelectric generators A41 and B42 are collected by data acquisition card 4. Thermoelectric generators A41 and B42 are two identical models of thermoelectric generators. For exothermic reactions, the output voltage of the programmable DC power supply A33 is changed to control and track the heating power of the exothermic reaction heating film A31, simulating the exothermic process in the microchannel reaction chip B22. When the difference between TEC and TER is ΔV...i When the voltage (in mV) approaches 0, the output voltage U of the programmable DC power supply A33 in real time is obtained. PC (Unit: V), calculate the heating power P of the heating film A31 in tracking the exothermic reaction. A (Unit: mW). For endothermic reactions, the output voltage of the programmable DC power supply B34 is changed to control the heating power of the endothermic reaction heating film B32, compensating for the heat absorbed by the endothermic reaction in the microchannel reaction chip B22. When the absolute value of the difference between TEC and TER is ΔV... i When the voltage (in mV) approaches 0, the output voltage U of the programmable DC power supply B34 in real time is obtained. PR (Unit: V), calculate the heating power P of the thin film B32 as it undergoes an endothermic reaction. B (Unit: mW). The heat absorbed and released during the reaction process, Q (unit: mJ), is calculated based on the residence time of the material in the reaction chip, and then the heat of reaction, ΔH (unit: kJ / mol), is calculated.

[0076] The methods specifically include:

[0077] (1) Loading: Select a solvent with the same specific heat capacity as the reactant in the first injection pump B and the second injection pump B and load it into three syringes, respectively into the first injection pump A, the second injection pump A and the quencher injection pump A. Load the reactant into two syringes, respectively into the first injection pump B and the second injection pump B. Load the quencher into the syringe and into the quencher injection pump B. Set the temperature of the material preheating aluminum block and the reaction isothermal aluminum block according to the reaction conditions, and heat or cool down to the target temperature at a constant rate.

[0078] (2) Feeding: The syringe feed rate is set according to the reaction conditions, and the flow rates of the first injection pump A and the first injection pump B are kept consistent. The flow rates of the second injection pump A and the second injection pump B are also kept consistent. The flow rates of the quencher injection pump A and the quencher injection pump B are kept consistent. The reaction residence time is controlled by the feeding rate. The injection pumps are simultaneously turned on and fed continuously through the central control system. The voltage signals TEC and TER of the thermoelectric generator A and thermoelectric generator B are monitored in real time through the data acquisition system during the reaction process. The output voltage U of the programmable DC power supply A is set. PC and the output voltage U of the programmable DC power supply B PR The voltage is 0V. Wait 10 minutes until the voltage signals TEC and TER of thermoelectric generator A and thermoelectric generator B stabilize.

[0079] (3) Dynamically track the reference heat, such as Figure 5 As shown, Table 1 is Figure 5 Δi and ΔV corresponding to the values ​​of i being 1, 2, 3, and 4 respectively. iValue. If initially TEC > TER, it is determined that an exothermic reaction is occurring in the microchannel reaction chip B. By changing the output voltage of the programmable DC power supply A, the heating power of the heating film A for tracking the exothermic reaction is controlled, and the exothermic process in the microchannel reaction chip B is simulated in the microchannel reference chip A until the absolute value △V of the difference between TEC and TER i is less than 1 mV. At this time, it is considered that the heat generated by the heating film A for tracking the exothermic reaction is the heat released by the reaction in the microchannel reaction chip B, and the output voltage U of the programmable DC power supply A at this time is recorded PC , then the heating power P of the heating film A for tracking the exothermic reaction A is:

[0080]

[0081] Table 1

[0082]

[0083] In the formula, R A is the resistance of the heating film A for tracking the exothermic reaction (unit: Ω);

[0084] If initially TEC < TER, it is determined that an endothermic reaction is occurring in the microchannel reaction chip B. By changing the output voltage of the programmable DC power supply B, the heating power of the heating film B for tracking the endothermic reaction is controlled to compensate for the heat absorbed by the endothermic reaction in the microchannel reaction chip B until the absolute value △V of the difference between TEC and TER i is less than 1 mV. At this time, it is considered that the heat generated by the heating film B for tracking the endothermic reaction is the heat absorbed by the reaction in the microchannel reaction chip B, and the output voltage U of the programmable DC power supply B at this time is recorded PR , then the heating power P of the heating film B for tracking the endothermic reaction B is:

[0085]

[0086] In the formula, R B is the resistance of the heating film B for tracking the exothermic reaction (unit: Ω);

[0087] (4) Calculate the heat of reaction. According to the volume flow rate set by the syringe pump, calculate the residence time t (unit: s) of the material in the reaction chip:

[0088]

[0089] In the formula, V is the volume of the reaction channels of the microchannel reference chip A and the microchannel reaction chip B (unit: μl), q V1 is the volume flow rate of the materials set by the first syringe pump A and the first syringe pump B (unit: μl / min), q V2The volumetric flow rate (in μl / min) of the material set for the second injection pump A and the second injection pump B.

[0090] Calculate the heat absorption and release Q (in mJ) of the reaction process based on the heating power of the heating film (formulas (1) and (2)):

[0091] Q = P × t (4)

[0092] In the formula, for an exothermic reaction, P = P A For an endothermic reaction, P = P B .

[0093] Calculate the amount of substance n (in mol) of the reactants:

[0094]

[0095] In the formula q V c is the volumetric flow rate of a reactant (in μl / min), and c is the molar concentration of a reactant (in mol / l).

[0096] The molar enthalpy change (ΔH) of the reaction process is:

[0097]

[0098] Example 1

[0099] This embodiment simulates the exothermic reaction in the microchannel reaction chip B by heating the heating film B that tracks the endothermic reaction, thereby verifying the accuracy of the device. The experimental results are as follows: Figure 6 As shown.

[0100] Water was added to the microchannel reference chip A and the microchannel reaction chip B at a rate of 1 ml / min through the first feed port A and the first feed port B, respectively, and the system temperature was 30℃.

[0101] First, a voltage U is applied to the heating film B, which is tracking the endothermic reaction, via a programmable DC power supply B. PR =3.18V. After the signal stabilizes, gradually increase the output voltage of the programmable DC power supply A until the absolute value of the difference between TEC and TER is ΔV. i If the voltage is less than 1mV, record the value of U at this time. PC =3.1773V. The error is 0.85%.

[0102] Example 2

[0103] This embodiment uses the dilution of 96% concentrated sulfuric acid to 80% with water as an example to illustrate the calorimetric method of the present invention, and further verifies the accuracy of the method through calculation. Experimental results are as follows: Figure 7As shown.

[0104] The first injection pump A, the second injection pump A, the quencher injection pump A, the second injection pump B, and the quencher injection pump B all contain water. The first injection pump B contains concentrated sulfuric acid with a mass fraction of 96%. Let q be the value of the solution. V1 =60μl / min, q V2 =22.15 μl / min, system temperature is 25℃.

[0105] Experimental steps

[0106] (1) Loading: Water is loaded into 5 syringes and placed into the first injection pump A, the second injection pump A, the quencher injection pump A, the second injection pump B and the quencher injection pump B respectively. Concentrated sulfuric acid with a mass fraction of 96% is loaded into the syringe and placed into the first injection pump B. The temperature of the material preheating aluminum block and the reaction constant temperature aluminum block is set to 25°C.

[0107] (2) Feeding: Set the syringe feed rate according to the reaction conditions, and control the flow rates of the first injection pump A and the first injection pump B to be consistent, q V1 =60μl / min, the flow rate of the second syringe pump A and the second syringe pump B are the same, q V2 =22.15μl / min, the flow rate of quencher injection pump A and quencher injection pump B is the same at 100μl / min. The injection pumps are started simultaneously and continuously fed through the central control system. The voltage signals TEC and TER of thermoelectric generator A and thermoelectric generator B are monitored in real time through the data acquisition system during the reaction process. The output voltage U of programmable DC power supply A is set. PC and the output voltage U of the programmable DC power supply B PR The voltage is 0V. Wait 10 minutes until the voltage signals TEC and TER of thermoelectric generator A and thermoelectric generator B stabilize.

[0108] (3) Dynamically track the reference heat, such as Figure 5 Initially, TEC > TER, indicating that an exothermic reaction is occurring in microchannel reaction chip B. The output voltage of programmable DC power supply A is changed to control and track the heating power of the exothermic reaction heating film A, simulating the exothermic process in microchannel reaction chip B in microchannel reference chip A, until the absolute value of the difference between TEC and TER reaches ΔV. i If the voltage is less than 1mV, record the output voltage U of the programmable DC power supply A at this time. PC =3.6970V, then the heating power P of the exothermic reaction heating film A is tracked. A =436.246mW.

[0109] (4) Calculate the heat of reaction. Calculate the residence time t (in seconds) of the material in the reaction chip based on the volumetric flow rate set by the injection pump:

[0110]

[0111] Calculate the heat released during the reaction process, Q (in mJ):

[0112] Q=436.246×131.47=57351.88

[0113] Calculate the amount of substance n (in mol) of the reactants:

[0114]

[0115] In the formula q V c is the volumetric flow rate of a reactant (in μl / min), and c is the molar concentration of a reactant (in mol / l).

[0116] The molar enthalpy change (ΔH) of the reaction process is:

[0117]

[0118] (5) Result verification. According to the literature, the heat of dilution of concentrated sulfuric acid from 96% to 80% is 23.69591 kJ / mol. The heat of dilution obtained by this method has an error of 1.9% compared with the value reported in the literature.

[0119] Example 3

[0120] This embodiment uses the diazotization reaction of aniline hydrochloride with sodium nitrite as an example to illustrate the application of this invention in the calorimetry of rapid, strongly exothermic, and hazardous reactions. Experimental results are as follows: Figure 8 As shown.

[0121] Experimental steps

[0122] (1) Loading: Water is loaded into 4 syringes and placed into the first injection pump A, the second injection pump A, the quencher injection pump A, and the quencher injection pump B, respectively. 2.3 ml of aniline and 6.5 ml of concentrated hydrochloric acid are mixed and diluted with water to 250 ml to prepare an aniline hydrochloride solution. The solution is loaded into the syringe and transferred to the first injection pump B. 1.8113 g of sodium nitrite is diluted with water to 250 ml to prepare a sodium nitrite aqueous solution. The molar ratio of aniline hydrochloride to sodium nitrite is 1:1.05. The temperature of the preheated aluminum block and the reaction isothermal aluminum block is set to 0 °C.

[0123] (2) Feeding: Set the syringe feed rate according to the reaction conditions, and control the flow rates of the first injection pump A and the first injection pump B to be consistent, q V1 =1350μl / min, the flow rate of the second syringe pump A and the second syringe pump B are the same, q V2=1350μl / min, quencher injection pump A and quencher injection pump B have the same flow rate of 1000μl / min. The injection pumps are started simultaneously and continuously fed through the central control system. The voltage signals TEC and TER of thermoelectric generator A and thermoelectric generator B are monitored in real time through the data acquisition system during the reaction process. The output voltage U of programmable DC power supply A is set. PC and the output voltage U of the programmable DC power supply B PR The voltage is 0V. Wait 10 minutes until the voltage signals TEC and TER of thermoelectric generator A and thermoelectric generator B stabilize.

[0124] (3) Dynamically track the reference heat, such as Figure 5 Initially, TEC > TER, indicating that an exothermic reaction is occurring in microchannel reaction chip B. The output voltage of programmable DC power supply A is changed to control and track the heating power of the exothermic reaction heating film A, simulating the exothermic process in microchannel reaction chip B in microchannel reference chip A, until the absolute value of the difference between TEC and TER reaches ΔV. i If the voltage is less than 1mV, record the output voltage U of the programmable DC power supply A at this time. PC =3.6210V, then the heating power P of the exothermic reaction heating film A is tracked. A = 416.415mW.

[0125] (4) Calculate the heat of reaction. Calculate the residence time t (in seconds) of the material in the reaction chip based on the volumetric flow rate set by the injection pump:

[0126]

[0127] Calculate the heat released during the reaction process, Q (in mJ):

[0128] Q = 416.415 × 4 = 1665.66

[0129] In this implementation case, the total material consumption of the calorimetric process is less than 20ml, and the device operates safely and stably with high signal sensitivity.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for dynamically tracking a reference continuous calorimeter at a microscale, characterized in that, include: A material inlet / outlet system; the material inlet / outlet system is connected to a microscale continuous reaction system; the material inlet / outlet system is controlled by a central control and data acquisition system, and injects materials into the microscale continuous reaction system; The material inlet and outlet system includes an injection pump controller (7), a recovery tank A (74), a recovery tank B (78), and an injection pump. The injection pump controller (7) is connected to the injection pump to control the operation status and operating parameters of the injection pump. The injection pumps include a first injection pump A (71), a second injection pump A (72), a quencher injection pump A (73), a first injection pump B (75), a second injection pump B (76), and a quencher injection pump B (77). The first injection pump A (71) is connected to the first feed port A (211) on the microchannel reference chip A (21) through the material preheating aluminum block (61) and the material inlet / outlet interface A (51). The second injection pump A (72) is connected to the second feed port A (212) on the microchannel reference chip A (21) through the material preheating aluminum block (61) and the material inlet / outlet interface A (51). The quencher injection pump A (73) is connected to the quencher feed port A (213) on the microchannel reference chip A (21) through the material preheating aluminum block (61) and the material inlet / outlet interface A (51). The recovery tank A (74) is connected to the discharge port A (214) on the microchannel reference chip A (21) through the material preheating aluminum block (61) and the material inlet / outlet interface A (51). The first injection pump B (75) is connected to the first feed port B (221) on the microchannel reference chip B (22) through the material preheating aluminum block (61) and the material inlet / outlet interface B (52). The second injection pump B (76) is connected to the second feed port B (222) on the microchannel reference chip B (22) through the material preheating aluminum block (61) and the material inlet / outlet interface B (52). The quencher injection pump B (77) is connected to the quencher feed port B (223) on the microchannel reference chip B (22) through the material preheating aluminum block (61) and the material inlet / outlet interface B (52). The recovery tank B (78) is connected to the discharge port B (224) on the microchannel reference chip B (22) through the material preheating aluminum block (61) and the material inlet / outlet interface B (52). Microscale continuous reaction system; the microchannel reaction chip B (22) in the microscale continuous reaction system is used to generate material reaction; the microchannel reference chip A (21) in the microscale continuous reaction system is used to simulate the endothermic and exothermic process of the reaction in the microchannel reaction chip B, and indirectly obtain the endothermic and exothermic heat in the microchannel reaction chip B (22); The microscale continuous reaction system includes, from top to bottom, a viewing window, a microchannel chip, a heating film, a thermoelectric generator, and a constant temperature device. The microchannel chip includes a microchannel reference chip A (21) and a microchannel reaction chip B (22) arranged in front and behind each other. The inlet and outlet of the microchannel reference chip A (21) and the microchannel reaction chip B (22) are on the same side, and the channels of the microchannel reference chip A (21) and the microchannel reaction chip B (22) are on the same side. The viewing window includes a material inlet / outlet viewing window (11) and a channel viewing window (12). The material inlet / outlet viewing window (11) is located above the inlet and outlet sides of the microchannel reference chip, and the channel viewing window (12) is located above the channel side of the microchannel reference chip. The heating film includes a heating film A (31) that tracks exothermic reactions and a heating film B (32) that tracks endothermic reactions. The heating film A (31) that tracks exothermic reactions is disposed below the microchannel reference chip A (21), and the heating film B (32) that tracks endothermic reactions is disposed below the microchannel reaction chip B (22). The thermoelectric generator includes thermoelectric generator A (41) and thermoelectric generator B (42). The thermoelectric generator A (41) is disposed below the heating film A (31) that tracks the exothermic reaction, and the thermoelectric generator B (42) is disposed below the heating film B (32) that tracks the endothermic reaction. The constant temperature device includes a material preheating aluminum block (61) and a reaction constant temperature aluminum block (62). The material preheating aluminum block (61) is located below the feed port side of the microchannel chip, and the reaction constant temperature aluminum block (62) is located below the channel port side of the microchannel chip. The material preheating aluminum block (61) has two grooves on the feed port side corresponding to the microchannel reference chip A (21) and the microchannel reaction chip B (22). Material inlet and outlet interface block A (51) and material inlet and outlet interface block B (52) are respectively provided in the grooves. Through holes are provided on the material inlet and outlet interface block A (51) and the material inlet and outlet interface block B (52) to allow the pipe of the injection pump to pass through. A central control and data acquisition system; the central control and data acquisition system controls the operation of the entire device and collects data on the absorption and release of heat, and calculates the heat of reaction based on the absorption and release of heat; The central control and data acquisition system includes a data acquisition card (4) and a central control and data acquisition unit (8). The positive and negative terminals of the programmable DC power supply A (33) are connected to the heating film A (31) that tracks the exothermic reaction, and the positive and negative terminals of the programmable DC power supply B (34) are connected to the heating film B (32) that tracks the endothermic reaction, respectively. The data acquisition card (4) is connected to the thermoelectric generator A (41) and the thermoelectric generator B (42), respectively. The central control and data acquisition unit (8) is connected to the programmable DC power supply A (33), the programmable DC power supply B (34), the data acquisition card (4), and the injection pump controller (7), respectively. The central control and data acquisition system acquires the voltage signal TEC of thermoelectric generator A (41) and the voltage signal TER of thermoelectric generator B (42) through the data acquisition card (4); When the initial TEC>TER, the micro-channel reaction chip B (22) is a heat-releasing reaction, the output voltage of the programmable DC power supply A (33) is changed to control the heat-releasing reaction heating film A (31) The heating power of the heat-releasing reaction in the micro-channel reaction chip B (22) simulates the heat-releasing process of the heat-releasing reaction, and when the difference between TEC and TER is ΔV i Tends to 0, the real-time output voltage U PC Of the programmable DC power supply A (33) is obtained, so as to calculate the heating power P A Of the heat-releasing reaction heating film A (31) When the initial TEC < TER, the micro-channel reaction chip B (22) is in an endothermic reaction. The output voltage of the programmable DC power supply B (34) is changed to control the heating power of the heating film B (32) to track the endothermic reaction, and the heat absorption of the endothermic reaction in the micro-channel reaction chip B (22) is compensated. When the absolute value of the difference between TEC and TER is ΔV i tends to 0, the output voltage U PR of the programmable DC power supply B (34) is obtained in real time. The heating power P B of the heating film B (32) tracking the endothermic reaction is calculated.

2. A method for dynamically tracking a reference continuous calorimeter at a microscale, implemented based on the device for dynamically tracking a reference continuous calorimeter at a microscale as described in claim 1, characterized in that, Includes the following steps: Materials are simultaneously and continuously added to microchannel reference chip A (21) and microchannel reaction chip B (22) at the same flow rate. A single solvent is introduced into microchannel reference chip A (21) through first injection pump A (71) and second injection pump A (72). The raw material for the test reaction is introduced into microchannel reaction chip B (22) through first injection pump B (75) and second injection pump B (76). Quenching reaction is carried out by simultaneously adding quencher to microchannel reference chip A (21) and microchannel reaction chip B (22) at the same flow rate using quencher injection pump A (73) and quencher injection pump B (77); The voltage signal TEC of thermoelectric generator A (41) and the voltage signal TER of thermoelectric generator B (42) are acquired by data acquisition card (4); For exothermic reactions, the heating power of the heating film A (31) is calculated by the output power of the programmable DC power supply A, and the heat of reaction Q is calculated by the residence time of the material in the reaction chip, and then the heat of reaction ΔH is calculated. For endothermic reactions, the heating power of the heating film B (32) is calculated by the output power of the programmable DC power supply B, and the heat release Q of the reaction process is calculated by the residence time of the material in the reaction chip, and then the heat of reaction ΔH is calculated.

3. The method for dynamically tracking a reference continuous calorimetry at a microscale according to claim 2, characterized in that, The temperatures of the material preheating aluminum block (61) and the reaction isothermal aluminum block (62) are set according to the reaction conditions, and the temperature is increased or decreased at a constant rate to the target temperature.

4. The method for dynamically tracking a reference continuous calorimetry at the microscale according to claim 2, characterized in that, The formula for calculating heating power is as follows: Among them, R A To track the resistance of the exothermic reaction heating thin film A, R B The resistance of the heated thin film B was measured to track the exothermic reaction.

5. The method for dynamically tracking a reference continuous calorimetry at the microscale according to claim 2, characterized in that, The steps for calculating the heat of reaction ΔH are as follows: The residence time t of the material in the reaction chip is calculated based on the volumetric flow rate set for the syringe pump. Where V is the volume of the reaction channel in microchannel reference chip A and microchannel reaction chip B, and q V1 The volumetric flow rate q of the material set for the first injection pump A and the first injection pump B V2 The volumetric flow rate of the material is set for the second injection pump A and the second injection pump B; Calculate the heat absorbed and released during the reaction process Q based on the heating power of the heating film: Where, for an exothermic reaction, P=P A For an endothermic reaction, P=P B ; Calculate the amount of substance n of the reactants: Where, q V Let c be the volumetric flow rate of a reactant, and c be the molar concentration of the reactant. The heat of reaction, ΔH, is: 。

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