Apparatus and method for dynamic tracking-based reference continuous heat measurement at microscale

Abstract

An apparatus and method for dynamic tracking-based reference continuous heat measurement at a microscale. The apparatus comprises: a material feeding and discharging system, wherein the material feeding and discharging system is connected to a microscale continuous reaction system, and the material feeding and discharging system is controlled by a central control and data acquisition system and injects a material into the microscale continuous reaction system; the microscale continuous reaction system, wherein a micro-channel reaction chip B (22) in the microscale continuous reaction system is used for causing material reaction, and a micro-channel reference chip A (21) in the microscale continuous reaction system is used for simulating a heat absorption / release process of the reaction in the micro-channel reaction chip B (22) and indirectly obtaining heat absorbed / released in the micro-channel reaction chip B (22); and the central control and data acquisition system, wherein the central control and data acquisition system acquires the heat absorbed / released and calculates reaction heat on the basis of the heat absorbed / released. According to the method, the whole heat measurement process is simple and rapid to operate, and the accuracy of heat measurement can be ensured without repeated correction.

Description

A device and method for dynamic tracking reference continuous calorimetry at microscale Technical Field

[0001] The present invention relates to the technical field of reaction heat measurement, and in particular to a device and method for dynamic tracking reference continuous calorimetry at a microscale. Background Art

[0002] Measuring calorimetric data for chemical reactions is crucial for process safety and reactor design, operation, and scale-up. Calorimeters can be used to obtain these data. Batch calorimetry is the most widely used calorimetric method. In recent years, continuously operated microreactors have become increasingly used in chemical production and process development. Microreactor technology allows for precise control of demanding process conditions. The small size of the reaction system in a microreactor reduces waste generation, improves safety, and reduces energy consumption. Measuring reaction calorimetry under continuous flow conditions can achieve higher yields, conversion rates, and selectivity, while also facilitating process automation. The small size and large surface area of ​​microchannel reactors allow for high heat transfer efficiency under steady-state conditions. This advantage is particularly evident for rapid, highly exothermic reactions. Calorimetric data generated using conventional batch calorimeters cannot be fully transferred to continuous-flow microreactors. Therefore, continuous-flow reaction calorimetry offers significant advantages.

[0003] Among the existing technologies for measuring reaction heat, patent CN114199937A discloses a calorimetric test method and device for ultra-low temperature reactions, which can realize ultra-low temperature constant temperature calorimetric testing of semi-batch reactions. However, this invention cannot realize the calorimetry of continuous flow reactions. Patent CN109459161A discloses a calorimetric test method and device for tubular reactions, which realizes the calorimetric testing of exothermic and endothermic tubular reactions, but its calibration process is complicated and the calculation is cumbersome. Patent CN110988035A discloses a method and device for testing continuous flow reaction heat using reference calorimetry, which realizes the test of reaction heat during continuous flow reactions, but its device structure is complicated, and the calorimetric process takes too long, and there is still a large error between the calorimetric result and the theoretical value. The typical microscale continuous calorimetry literature, "Characterization of reaction enthalpy and kinetics in a microscale flow platform," uses a microreactor chip to measure the heat of reaction of acetic anhydride hydrolysis. The test process is complex, and the process needs to be corrected before each calorimetric measurement. Furthermore, environmental influences cannot be completely eliminated, resulting in large errors.

[0004] Summary of the Invention

[0005] In response to the aforementioned technical challenges of measuring heat of reaction under continuous flow conditions, a device and method for dynamic tracking of reference continuous calorimetry at the microscale are provided. This invention primarily utilizes reference calorimetry to effectively eliminate environmental influences on the calorimetric process. Using dynamic tracking, the reaction endothermic and exothermic processes are simulated with high precision, allowing for rapid and accurate measurement of the heat of reaction. This addresses the technical challenges of measuring heat of reaction under continuous flow conditions.

[0006] The technical means adopted in the present invention are as follows:

[0007] A device for dynamic tracking of reference continuous calorimetry at a microscale, comprising:

[0008] Material inlet and outlet system; the material inlet and outlet system is connected to the micro-scale continuous reaction system; the material inlet and outlet system is controlled by the central control and data acquisition system to inject materials into the micro-scale continuous reaction system;

[0009] A microscale continuous reaction system; a microchannel reaction chip B in the microscale continuous reaction system is used to generate a material reaction; a microchannel reference chip A 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;

[0010] Central control and data acquisition system; the central control and data acquisition system controls the operation of the entire device and collects heat absorption and release data, and calculates the reaction heat based on the heat absorption and release.

[0011] Furthermore, the material inlet and outlet system includes a syringe pump controller, a recovery tank A, a recovery tank B and a syringe pump, and the syringe pump controller is connected to the syringe pump to control the operating state and operating parameters of the syringe pump;

[0012] 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.

[0013] Furthermore, the first syringe pump A is connected to the first feed port A on the microchannel reference chip A through the material preheating aluminum block and the material inlet and outlet interface A, the second syringe pump A is connected to the second feed port A on the microchannel reference chip A through the material preheating aluminum block and the material inlet and outlet interface A, the quencher syringe pump A is connected to the quencher feed port A on the microchannel reference chip A through the material preheating aluminum block and the material inlet and outlet interface A, and the recovery tank A is connected to the discharge port A on the microchannel reference chip A through the material preheating aluminum block and the material inlet and outlet interface A;

[0014] The first injection pump B is connected to the first feed port B on the microchannel reference chip B through the material preheating aluminum block and the material inlet and outlet interface B, the second injection pump B is connected to the second feed port B on the microchannel reference chip B through the material preheating aluminum block and the material inlet and outlet interface B, the quencher injection pump B is connected to the quencher feed port B on the microchannel reference chip B through the material preheating aluminum block and the material inlet and outlet interface B, and the recovery tank B is connected to the outlet B on the microchannel reference chip B through the material preheating aluminum block and the material inlet and outlet interface B.

[0015] Furthermore, the microscale continuous reaction system includes a visual window, a microchannel chip, a heating film, a thermoelectric power generation sheet and a constant temperature device arranged in sequence from top to bottom;

[0016] The microchannel chip includes a microchannel reference chip A and a microchannel reaction chip B arranged in front and back, wherein the inlet and outlet 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;

[0017] The visual windows include material inlet and outlet visual windows and channel visual windows. The material inlet and outlet visual windows are arranged above the inlet and outlet sides of the microchannel reference chip, and the channel visual windows are arranged above the channel side of the microchannel reference chip.

[0018] The heating film includes an exothermic reaction tracking heating film A and an endothermic reaction tracking heating film B. The exothermic reaction tracking heating film A is arranged below the microchannel reference chip A, and the endothermic reaction tracking heating film B is arranged below the microchannel reaction chip B.

[0019] The thermoelectric power generation sheet includes a thermoelectric power generation sheet A and a thermoelectric power generation sheet B. The thermoelectric power generation sheet A is arranged below the heat-tracing exothermic reaction heating film A, and the thermoelectric power generation sheet B is arranged below the heat-tracing endothermic reaction heating film B.

[0020] The constant temperature device includes a material preheating aluminum block and a reaction constant temperature aluminum block. The material preheating aluminum block is arranged below the feed port side of the microchannel chip, and the reaction constant temperature aluminum block is arranged below the channel port side of the microchannel chip. The material preheating aluminum block is provided with two grooves at positions corresponding to the feed port sides of the microchannel reference chip A and the microchannel reaction chip B. The grooves are respectively provided with material inlet and outlet interface blocks A and material inlet and outlet interface blocks B. The material inlet and outlet interface blocks A and material inlet and outlet interface blocks B are provided with through holes for allowing the pipes of the injection pump to pass through.

[0021] Furthermore, the central control and data acquisition system includes a data acquisition card and a central control and data acquisition device. The positive and negative poles of the programmable DC power supply A are respectively connected to the tracking exothermic reaction heating film A, and the positive and negative poles of the programmable DC power supply B are respectively connected to the tracking endothermic reaction heating film B. The data acquisition card is respectively connected to the thermoelectric power generation sheet A and the thermoelectric power generation sheet B. The central control and data acquisition device is respectively connected to the programmable DC power supply A, the programmable DC power supply B, the data acquisition card and the injection pump controller.

[0022] The present invention also provides a method for dynamic tracking of reference continuous calorimetry at a microscale, which is implemented based on any of the above-mentioned devices for dynamic tracking of reference continuous calorimetry at a microscale, and comprises the following steps:

[0023] Materials are continuously added to microchannel reference chip A and microchannel reaction chip B at the same flow rate simultaneously. A single solvent is introduced into microchannel reference chip A through the first syringe pump A and the second syringe pump A. Raw materials for the test reaction are introduced into microchannel reaction chip B through the first syringe pump B and the second syringe pump B.

[0024] The quenching agent is added to the microchannel reference chip A and the microchannel reaction chip B at the same flow rate through the quenching agent injection pump A and the quenching agent injection pump B to perform a quenching reaction;

[0025] The voltage signal TEC of the thermoelectric generator A and the voltage signal TER of the thermoelectric generator B are collected through the data acquisition card;

[0026] For exothermic reactions, the output power of the programmable DC power supply A is used to calculate and track the heat generation power of the exothermic reaction heating film A. The heat release Q of the reaction process is calculated by the residence time of the material in the reaction chip, and then the reaction heat ΔH is calculated;

[0027] For endothermic reactions, the output power of the programmable DC power supply B is used to calculate and track the heat generation power of the endothermic reaction heating film B. The heat release Q of the reaction process is calculated by the residence time of the material in the reaction chip, and then the reaction heat △H is calculated.

[0028] Furthermore, the temperature of the material preheating aluminum block and the reaction constant temperature aluminum block is set according to the reaction conditions, and the temperature is increased or decreased to the target temperature at a constant rate.

[0029] Furthermore, the calculation and tracking of the heating power of the exothermic reaction heating film A includes the following steps:

[0030] When TEC>TER at the beginning, the microchannel reaction chip B is undergoing an exothermic reaction. By changing the output voltage of the programmable DC power supply A to control the heating power of the heating film A to track the exothermic reaction, the exothermic process of the exothermic reaction in the microchannel reaction chip B is simulated. When the difference between TEC and TER is △Vi When the real-time output voltage U of the programmable DC power supply A is obtained PC , and thus calculate the heating power P of the film A by tracking the exothermic reaction A ;

[0031] When TEC is less than TER at the beginning, the microchannel reaction chip B is undergoing an endothermic reaction. By changing the output voltage of the programmable DC power supply B to control the heating power of the heating film B to track the endothermic reaction, the heat absorbed by the endothermic reaction in the microchannel reaction chip B is compensated. When the absolute value of the difference between TEC and TER is △V i When the real-time output voltage U of the programmable DC power supply B is obtained, PR , calculate the heating power P of the heating film B by tracking the endothermic reaction B .

[0032] Furthermore, the calculation formula of heating power is as follows:

[0033] Among them, R A To track the resistance of film A heated by the exothermic reaction, R B The resistance of film B is heated to track the exothermic reaction.

[0034] Furthermore, the calculation steps of the reaction heat ΔH are as follows:

[0035] Calculate the residence time t of the material in the reaction chip according to the volume flow rate set by the injection pump:

[0036] Where V is the volume of the reaction channel of microchannel reference chip A and microchannel reaction chip B, q V1 The volume flow rate of the material set for the first injection pump A and the first injection pump B, q V2 The volume flow rate of the material set for the second injection pump A and the second injection pump B;

[0037] The heat absorption and release Q of the reaction process is calculated based on the heating power of the heated film: Q = P × t

[0038] Where, for an exothermic reaction, P = P A For an endothermic reaction, P = P B ;

[0039] Calculate the amount of reactant n:

[0040] Among them, q V is the volume flow rate of a reactant, c is the molar concentration of a reactant;

[0041] The heat of reaction ΔH is:

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] The device of the present invention uses a microscale reaction chip with high mass and heat transfer efficiency, can realize single reaction with high reactant concentration, and 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 the safety of the process, and can realize calorimetry of dangerous chemical reactions.

[0044] The device of the present invention is equipped with a microchannel reference chip A and a microchannel reaction chip B. The two chips have exactly the same structure. Samples are injected simultaneously during the reaction process, and the flow rate is strictly controlled, eliminating 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 actual heat change of the reaction.

[0045] The present invention uses a central control and data acquisition device to realize control of an injection pump, system temperature and a direct current power supply, including realizing online real-time control of starting and stopping the injection pump, setting flow rate and setting working time by establishing a communication link between the central control and data acquisition device and an injection pump controller; realizing online real-time control of the direct current power supply on and off, and dynamically controlling the power supply output voltage during the experiment by establishing a communication link between the central control and data acquisition device and a programmable direct current power supply A and a programmable direct current power supply B; controlling the temperature of a material preheating aluminum block and a reaction constant temperature aluminum block by establishing communication between the central control and data acquisition device and a constant temperature pump; and simultaneously performing online data acquisition and processing, and real-time acquisition of the voltage signal of the data acquisition card by linking the central control and data acquisition device and a data acquisition card.

[0046] The entire calorimetric process of the present invention is rapid, and accurate calorimetric data can be obtained without correction before each calorimetric measurement.

[0047] The apparent results obtained by the dynamic tracking reference calorimetry test method of the present invention can provide more practical and effective guidance for engineering design, process safety and process optimization of energy conversion and transfer design. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0049] FIG1 is a schematic structural diagram of the present invention.

[0050] FIG2 is an exploded view of the microscale continuous reaction system of the present invention.

[0051] FIG3 is a schematic diagram of the structure of the micro-reaction chip of the present invention.

[0052] FIG4 is a schematic structural diagram of the thermostat of the present invention.

[0053] FIG5 is a dynamic tracking reference logic diagram of the present invention.

[0054] FIG6 is a diagram showing the experimental results of Example 1 of the present invention.

[0055] FIG7 is a diagram showing the experimental results of Example 2 of the present invention.

[0056] FIG8 is a diagram showing the experimental results of Example 3 of the present invention.

[0057] In the figure: 11. Material inlet and outlet visual window; 12. Channel visual window; 21. Microchannel reference chip A; 211. First feed port A; 212. Second feed port A; 213. Quenching agent feed port A; 214. Discharge port A; 22. Microchannel reaction chip B; 221. First feed port B; 222. Second feed port B; 223. Quenching agent feed port B; 224. Discharge port B; 31. Tracking exothermic reaction heating film A; 32. Tracking endothermic reaction heating film B; 33. Programmable DC power supply A; 34. Programmable DC power supply B; 4. Data acquisition card; 41. Thermoelectric power generation sheet A; 42. Thermoelectric power generation sheet B; 51. Material inlet and outlet interface block A; 52. Material inlet and 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 device. DETAILED DESCRIPTION

[0058] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0059] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0060] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0061] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​described in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0062] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0063] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0064] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0065] As shown in Figures 1-4, the present invention provides a microscale dynamic tracking reference continuous calorimetry device, including a material inlet and outlet system, a microscale continuous reaction system, and a central control and data acquisition system.

[0066] The material inlet and outlet system includes a syringe pump controller 7, a first syringe pump A71, a second syringe pump A72, a quencher syringe pump A73, a recovery tank A74, a first syringe pump B75, a second syringe pump B76, a quencher syringe pump B77, and a recovery tank B78. The syringe pump controller 7 controls the operating status and parameters of all syringe pumps within the system. The first syringe pump A71, the second syringe pump A72, the quencher syringe pump A73, and the recovery tank A74 are connected to the first feed port A211, the second feed port A212, the quencher feed port A213, and the discharge port A214 of the microchannel reference chip A21, respectively, via the material preheating aluminum block 61 and the material inlet and outlet interface block A51. The first injection pump B75, the second injection pump B76, the quenching agent injection pump B77 and the recovery tank B78 are respectively connected to the first feed port B221, the second feed port B222, the quenching agent feed port B223 and the discharge port B224 on the microchannel reaction chip B22 through the material preheating block 61 and the material inlet and outlet interface block B52.

[0067] The microscale continuous reaction system includes a material inlet and outlet viewing window 11, a channel viewing window 12, a microchannel reference chip A21, a microchannel reaction chip B22, an exothermic reaction tracking heating film A31, an endothermic reaction tracking heating film B32, a thermoelectric generator A41, a thermoelectric generator B42, a material inlet and outlet interface block A51, a material inlet and outlet interface block B52, a material preheating aluminum block 61, and a reaction constant temperature aluminum block 62. These are arranged in sequence as shown in Figure 2 and secured with screws on all sides. The microchannel reference chip A21 and the microchannel reaction chip B22 are identical in structure, the exothermic reaction tracking heating film A31 and the endothermic reaction tracking heating film B32 are identical in model, and the thermoelectric generator A41 and the thermoelectric generator B42 are of the same model.

[0068] 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 via wires to the exothermic reaction tracking heating film A31, while the positive and negative electrodes of programmable DC power supply B34 are connected via wires to the endothermic reaction tracking heating film B32. The data acquisition card 4 is connected to the thermoelectric generator sheets A41 and B42. The central control and data acquisition unit 8 is connected to the programmable DC power supply A33, programmable DC power supply B34, the data acquisition card 4, and the syringe pump controller 7 via communication lines.

[0069] The present invention also provides a method for measuring the heat of a continuous flow reaction using a microscale dynamic tracking reference continuous calorimetry device, comprising the following steps:

[0070] Microchannel reference chip A21 and microchannel reaction chip B22 have identical structures. Materials are continuously added to both microchannel reference chip A21 and microchannel reaction chip B22 simultaneously at the same flow rate. A single solvent is introduced into microchannel reference chip A21 via first and second syringe pumps A71 and A72, while the test reaction feedstock is introduced into microchannel reaction chip B22 via first and second syringe pumps B75 and B76. Quencher is added to both microchannel reference chip A21 and microchannel reaction chip B22 simultaneously at the same flow rate via quencher syringe pumps A73 and B77, quenching the reaction in a timely manner to ensure experimental safety. The reaction residence time is controlled by controlling the rate of material addition. The voltage signals TEC and TER (in mV) from thermoelectric generator chip A41 and thermoelectric generator chip B42 are collected via data acquisition card 4. Thermoelectric generator chips A41 and B42 are of identical models. For the exothermic reaction, the output voltage of the programmable DC power supply A33 is changed to control the heating power of the exothermic reaction heating film A31, and the exothermic process of the exothermic reaction in the microchannel reaction chip B22 is simulated. When the difference between TEC and TER is △V iWhen the value (in mV) approaches 0, the output voltage U of the programmable DC power supply A33 is obtained in real time. PC (unit V), calculate the heating power P of the heat-generating film A31 by tracking the exothermic reaction A (Unit: mW). For endothermic reactions, the output voltage of the programmable DC power supply B34 is controlled to track the heating power of the endothermic reaction heating film B32, thereby 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 △V i When the value (in mV) approaches 0, the output voltage U of the programmable DC power supply B34 is obtained in real time. PR (unit V), calculate the heating power P of the tracking endothermic reaction heating film B32 B The residence time of the material in the reaction chip is used to calculate the heat absorption and release Q (in mJ) of the reaction process, and then the heat of reaction ΔH (in kJ / mol) is calculated.

[0071] The methods specifically include:

[0072] (1) Loading: Select a solvent with the same specific heat capacity as the reaction raw materials in the first injection pump B and the second injection pump B and load it into three syringes, which are respectively loaded into the first injection pump A, the second injection pump A and the quencher injection pump A; load the reaction raw materials into two syringes, which are respectively loaded into the first injection pump B and the second injection pump B; load the quencher into a syringe and load it into the quencher injection pump B; set the temperature of the material preheating aluminum block and the reaction constant temperature aluminum block according to the reaction conditions, and heat or cool it to the target temperature at a constant rate.

[0073] (2) Feeding: Set the syringe feeding speed 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, the flow rates of the second injection pump A and the second injection pump B to be consistent, and the flow rates of the quencher injection pump A and the quencher injection pump B to be consistent. The residence time of the reaction is controlled by the feeding speed. The injection pumps are simultaneously turned on and continuously fed through the central control system. The voltage signals TEC and TER of the thermoelectric generator A and the thermoelectric generator B during the reaction are collected in real time online by the data acquisition system to set the output voltage U of the programmable DC power supply A. PC and the output voltage U of the programmable DC power supply B PR Wait for 10 minutes until the voltage signals TEC and TER of thermoelectric generator A and thermoelectric generator B become stable.

[0074] (3) Dynamic tracking of reference calorimetry, as shown in Figure 5, Table 1 shows the Δi and ΔV corresponding to the values ​​of i in Figure 5 when they are 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:

[0075] Table 1

[0076] In the formula, R A is the resistance of the heating film A for tracking the exothermic reaction (unit: Ω);

[0077] 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 [[ID=2,5]]is:

[0078] In the formula, R B is the resistance of the heating film B for tracking the exothermic reaction (unit: Ω);

[0079] (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:

[0080] 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 material set by the first syringe pump A and the first syringe pump B (unit: μl / min), q V2 is the volume flow rate of the material set by the second syringe pump A and the second syringe pump B (unit: μl / min).

[0081] The heat absorption and release Q (unit: mJ) of the reaction process is calculated based on the heating power of the heated film (formulas (1) and (2)): Q = P × t (4)

[0082] Where, for an exothermic reaction, P = P A For an endothermic reaction, P = P B .

[0083] Calculate the amount of reactant n (in mol):

[0084] Where q V is the volume flow rate of a reactant (unit: μl / min), and c is the molar concentration of a reactant (unit: mol / l).

[0085] The molar heat of reaction △H (kJ / mol) of the reaction process is:

[0086] Example 1

[0087] In this embodiment, the accuracy of the device is verified by heating the tracking endothermic reaction heating film B to simulate the exothermic reaction in the microchannel reaction chip B. The experimental results are shown in FIG6 .

[0088] 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. The system temperature was 30°C.

[0089] First, a voltage U is applied to the film B that tracks the endothermic reaction through the editable DC power supply B. PR =3.18V, after the signal stabilizes, gradually increase the output voltage of the editable DC power supply A until the absolute value of the difference between TEC and TER reaches △V i Less than 1mV, record U PC =3.1773 V. The error is 0.85%.

[0090] Example 2

[0091] This example uses the dilution of 96% concentrated sulfuric acid to 80% by mass with water as an example to illustrate the calorimetric method of the present invention, and further verifies the accuracy of the method through calculation. The experimental results are shown in Figure 7.

[0092] The first injection pump A, the second injection pump A, the quenching agent injection pump A, the second injection pump B and the quenching agent injection pump B are all filled with water, and the first injection pump B is filled with concentrated sulfuric acid with a mass fraction of 96%. Set q V1 =60μl / min, q V2 =22.15μl / min, system temperature is 25℃.

[0093] Experimental procedures

[0094] (1) Loading: Water is loaded into 5 syringes and respectively loaded 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. Concentrated sulfuric acid with a mass fraction of 96% is loaded into a syringe and not loaded 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.

[0095] (2) Feeding: Set the syringe feeding speed 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 is the same, q V2 =22.15μl / min, the flow rate of quencher injection pump A and quencher injection pump B is consistent at 100μl / min, the injection pumps are started simultaneously and continuously fed through the central control system, and the voltage signals TEC and TER of the thermoelectric generator A and the thermoelectric generator B during the reaction are collected in real time through the data acquisition system to set the output voltage U of the programmable DC power supply A. PC and the output voltage U of the programmable DC power supply B PR Wait for 10 minutes until the voltage signals TEC and TER of thermoelectric generator A and thermoelectric generator B become stable.

[0096] (3) Dynamic tracking of reference calorimetry, as shown in Figure 5, initially TEC>TER, it is determined that the microchannel reaction chip B is undergoing an exothermic reaction, the output voltage of the programmable DC power supply A is changed to control the heating power of the heating film A that tracks the exothermic reaction, and the exothermic process in the microchannel reaction chip B is simulated in the microchannel reference chip A until the absolute value of the difference between TEC and TER is △V i Less than 1mV, record the output voltage U of 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.

[0097] (4) Calculate the reaction heat and calculate the residence time t (in seconds) of the material in the reaction chip according to the volume flow rate set by the injection pump:

[0098] Calculate the heat released during the reaction (in mJ): Q = 436.246 × 131.47 = 57351.88

[0099] Calculate the amount of reactant n (in mol):

[0100] Where q Vis the volume flow rate of a reactant (unit: μl / min), and c is the molar concentration of a reactant (unit: mol / l).

[0101] The molar heat of reaction △H (kJ / mol) of the reaction process is:

[0102] (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 difference between the heat of dilution obtained by this method and the value reported in the literature is 1.9%.

[0103] Example 3

[0104] This example uses the diazotization reaction of aniline hydrochloride and sodium nitrite as an example to illustrate the application of the present invention in the calorimetry of dangerous reactions with rapid and strong exothermic reactions. The experimental results are shown in Figure 8.

[0105] Experimental procedures

[0106] (1) Loading: Water is loaded into 4 syringes and loaded 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 a 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 material preheating aluminum block and the reaction constant temperature aluminum block is set to 0°C.

[0107] (2) Feeding: Set the syringe feeding speed 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 is the same, q V2 =1350μl / min, the flow rate of quencher injection pump A and quencher injection pump B is consistent at 1000μl / min, the injection pumps are started simultaneously and continuously fed through the central control system, and the voltage signals TEC and TER of the thermoelectric generator A and the thermoelectric generator B during the reaction are collected in real time through the data acquisition system to set the output voltage U of the programmable DC power supply A. PC and the output voltage U of the programmable DC power supply B PR Wait for 10 minutes until the voltage signals TEC and TER of thermoelectric generator A and thermoelectric generator B become stable.

[0108] (3) Dynamic tracking of reference calorimetry, as shown in Figure 5, initially TEC>TER, it is determined that the microchannel reaction chip B is undergoing an exothermic reaction, the output voltage of the programmable DC power supply A is changed to control the heating power of the heating film A that tracks the exothermic reaction, and the exothermic process in the microchannel reaction chip B is simulated in the microchannel reference chip A until the absolute value of the difference between TEC and TER is △V i Less than 1mV, record the output voltage U of 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.

[0109] (4) Calculate the reaction heat and calculate the residence time t (in seconds) of the material in the reaction chip according to the volume flow rate set by the injection pump:

[0110] Calculate the heat released during the reaction (in mJ): Q = 416.415 × 4 = 1665.66

[0111] In this embodiment, the total material consumption in the calorimetric process is less than 20 ml, and the device operates safely and stably with high signal sensitivity.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 dynamic tracking of reference continuous calorimetry at microscale, characterized in that: include: Material inlet and outlet system; the material inlet and outlet system is connected to the microscale continuous reaction system; the material inlet and outlet system is controlled by the central control and data acquisition system to inject materials into the microscale continuous reaction system; A microscale continuous reaction system; a microchannel reaction chip B (22) in the microscale continuous reaction system is used to generate a material reaction; a 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); Central control and data acquisition system; the central control and data acquisition system controls the operation of the entire device and collects heat absorption and release data, and calculates the reaction heat based on the heat absorption and release.

2. The device for dynamic tracking reference continuous calorimetry at microscale according to claim 1, characterized in that: The material inlet and outlet system comprises an injection pump controller (7), a recovery tank A (74), a recovery tank B (78) and an injection pump, wherein the injection pump controller (7) is connected to the injection pump to control the operating state 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).

3. The device for dynamic tracking reference continuous calorimetry at microscale according to claim 2, characterized in that: 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 and 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 and outlet interface A (51); the quenching agent injection pump A (73) is connected to the quenching agent feed port A (213) on the microchannel reference chip A (21) through the material preheating aluminum block (61) and the material inlet and outlet interface A (51); and 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 and 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 and 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 and outlet interface B (52); the quenching agent injection pump B (77) is connected to the quenching agent feed port B (223) on the microchannel reference chip B (22) through the material preheating aluminum block (61) and the material inlet and outlet interface B (52); and 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 and outlet interface B (52).

4. The device for dynamic tracking reference continuous calorimetry at microscale according to claim 1, characterized in that: The microscale continuous reaction system comprises a visual window, a microchannel chip, a heating film, a thermoelectric power generation sheet and a constant temperature device arranged in sequence from top to bottom; The microchannel chip comprises a microchannel reference chip A (21) and a microchannel reaction chip B (22) arranged front and back, wherein the inlet and outlet ports of the microchannel reference chip A (21) and the microchannel reaction chip B (22) are located on the same side, and the channels of the microchannel reference chip A (21) and the microchannel reaction chip B (22) are located on the same side; The visual window comprises a material inlet and outlet visual window (11) and a channel visual window (12), wherein the material inlet and outlet visual window (11) is arranged above the inlet and outlet sides of the microchannel reference chip, and the channel visual window (12) is arranged above the channel side of the microchannel reference chip; The heating film comprises an exothermic reaction tracking heating film A (31) and an endothermic reaction tracking heating film B (32), wherein the exothermic reaction tracking heating film A (31) is arranged below the microchannel reference chip A (21), and the endothermic reaction tracking heating film B (32) is arranged below the microchannel reaction chip B (22); The thermoelectric power generation sheet comprises a thermoelectric power generation sheet A (41) and a thermoelectric power generation sheet B (42), wherein the thermoelectric power generation sheet A (41) is arranged below the exothermic reaction heating film A (31) and the thermoelectric power generation sheet B (42) is arranged below the endothermic reaction heating film B (32). The thermostatic device comprises a material preheating aluminum block (61) and a reaction thermostatic aluminum block (62). The material preheating aluminum block (61) is arranged below the feed inlet side of the microchannel chip, and the reaction thermostatic aluminum block (62) is arranged below the channel outlet side of the microchannel chip. The material preheating aluminum block (61) is provided with two grooves at positions corresponding to the feed inlet sides of the microchannel reference chip A (21) and the microchannel reaction chip B (22). The grooves are provided with material inlet and outlet interface blocks A (51) and material inlet and outlet interface blocks B (52), respectively. The material inlet and outlet interface blocks A (51) and material inlet and outlet interface blocks B (52) are provided with through holes for allowing the pipeline of the injection pump to pass through.

5. The device for dynamic tracking reference continuous calorimetry at microscale according to claim 1, characterized in that: The central control and data acquisition system comprises a data acquisition card (4) and a central control and data acquisition device (8); the positive and negative electrodes of the programmable DC power supply A (33) are respectively connected to the tracking exothermic reaction heating film A (31); the positive and negative electrodes of the programmable DC power supply B (34) are respectively connected to the tracking endothermic reaction heating film B (32); the data acquisition card (4) is respectively connected to the thermoelectric power generation sheet A (41) and the thermoelectric power generation sheet B (42); the central control and data acquisition device (8) is respectively 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).

6. A method for dynamically tracking reference continuous calorimetry at microscale, implemented based on the device for dynamically tracking reference continuous calorimetry at microscale as claimed in any one of claims 1 to 5, characterized in that: The steps include: Add the same flow rate to the microchannel reference chip A (21) and the microchannel reaction chip B (22) simultaneously and continuously. Materials, a single solvent is introduced into the microchannel reference chip A (21) through the first injection pump A (71) and the second injection pump A (72), and raw materials for the test reaction are introduced into the microchannel reaction chip B (22) through the first injection pump B (75) and the second injection pump B (76); A quenching agent is added to the microchannel reference chip A (21) and the microchannel reaction chip B (22) at the same flow rate through a quenching agent injection pump A (73) and a quenching agent injection pump B (77) to perform a quenching reaction; The voltage signal TEC of the thermoelectric power generation sheet A (41) and the voltage signal TER of the thermoelectric power generation sheet B (42) are collected by a data collection card (4); For the exothermic reaction, the heat generation power of the exothermic reaction heating film A (31) is tracked by calculating the output power of the programmable DC power supply A, and the heat generation Q of the reaction process is calculated by the residence time of the material in the reaction chip, and then the reaction heat ΔH is calculated; For endothermic reactions, the output power of the programmable DC power supply B is used to calculate and track the heat generation power of the endothermic reaction heating film B (32), and the heat release Q of the reaction process is calculated by the residence time of the material in the reaction chip, thereby calculating the reaction heat ΔH.

7. The method for dynamic tracking reference continuous calorimetry at microscale according to claim 6, characterized in that: The temperature of the material preheating aluminum block (61) and the reaction constant temperature aluminum block (62) is set according to the reaction conditions, and the temperature is increased or decreased at a constant rate to the target temperature.

8. The method for dynamic tracking reference continuous calorimetry at microscale according to claim 7, characterized in that: The calculation of the heating power of the exothermic reaction heating film A (31) includes the following steps: When TEC>TER at the beginning, an exothermic reaction is carried out in the microchannel reaction chip B (22). The output voltage of the programmable DC power supply A (33) is changed to control the heat generation power of the heating film A (31) for tracking the exothermic reaction, and the exothermic process of the exothermic reaction in the microchannel reaction chip B (22) is simulated. When the difference between TEC and TER is △V i When it approaches 0, the output voltage U of the real-time programmable DC power supply A (33) is obtained. PC , thereby calculating the heating power P of the heating film A (31) by tracking the exothermic reaction A ; When TEC is less than TER at the beginning, the microchannel reaction chip B (22) is undergoing an endothermic reaction. By changing the output voltage of the programmable DC power supply B (34), the heating power of the heating film B (32) for tracking the endothermic reaction is controlled to compensate for the endothermic heat of the endothermic reaction in the microchannel reaction chip B (22). When the absolute value △V of the difference between TEC and TER is i When it approaches 0, the output voltage U of the real-time programmable DC power supply B (34) is obtained. PR , calculate the heating power P of the film B (32) heated by the tracking endothermic reaction B .

9. The method for dynamic tracking reference continuous calorimetry at microscale according to claim 8, characterized in that: The calculation formula of heating power is as follows: Among them, R A To track the exothermic reaction heating the resistance of film A, R B The resistance of film B is heated to track the exothermic reaction.

10. The method for dynamic tracking reference continuous calorimetry at microscale according to claim 9, characterized in that: The calculation steps of reaction heat △H are as follows: The residence time t of the material in the reaction chip is calculated according to the volume flow rate set by the injection pump: Where V is the volume of the reaction channel of microchannel reference chip A and microchannel reaction chip B, q V1 The volume flow rate of the material set for the first injection pump A and the first injection pump B, q V2 The volume flow rate of the material set for the second injection pump A and the second injection pump B; The heat absorption and release Q of the reaction process is calculated based on the heating power of the heated film: Q=P×t Where, for an exothermic reaction, P = P A For an endothermic reaction, P = P B ; Calculate the amount of reactant n: Among them, q V is the volume flow rate of a certain reactant, c is the molar concentration of a certain reactant; The heat of reaction △H is:

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