WO2022213574A1

WO2022213574A1 - Adiabatic accelerating rate calorimeter based on sample cell inner surface temperature measurement

Info

Publication number: WO2022213574A1
Application number: PCT/CN2021/124023
Authority: WO
Inventors: 蒋军成; 汤波涛; 倪磊; 殷亮; 颜天一
Original assignee: 南京工业大学
Priority date: 2021-04-06
Filing date: 2021-10-15
Publication date: 2022-10-13
Also published as: CN113030173A; CN113030173B

Abstract

An adiabatic accelerating rate calorimeter based on sample cell inner surface temperature measurement. The structure of the adiabatic accelerating rate calorimeter comprises a sample temperature detection thermocouple (1), a sample cell (2), a sample cell heater, and a sample cell inner surface temperature measurement thermocouple (5), wherein the sample cell heater comprises a sample cell wall heater A (3), a sample cell wall heater B (4), a sample cell wall heater C (10), a sample cell wall heater D (11), and a sample cell bottom heater (6); the sample temperature detection thermocouple (1) is inserted into the sample cell (2) from an upper opening of the sample cell (2); the sample cell wall heater A (3), the sample cell wall heater B (4), the sample cell wall heater C (10), and the sample cell wall heater D (11) are respectively fixed on the peripheral side walls of the sample cell (2); the sample cell bottom heater (6) is fixed at the bottom of the sample cell (2); the sample cell inner surface temperature measurement thermocouple (5) is inserted into the sample cell wall of the sample cell (2); and the end part of the sample cell inner surface temperature measurement thermocouple (5) is close to the inner surface of the sample cell (2). The problems that the sample cell absorbs reaction heat, heat loss is caused, and ideal heat insulation is difficult to achieve are solved.

Description

An Adiabatic Acceleration Calorimeter Based on Surface Temperature Measurement of Sample Cell

technical field

The invention relates to an adiabatic acceleration calorimeter based on the temperature measurement of the inner surface of a sample pool, and belongs to the field of accelerated calorimetry technology and instruments for chemical process safety.

Background technique

As the world's largest chemical country, the scale of my country's hazardous chemicals market has been growing, reaching 6.87 trillion yuan in 2018. Most of the raw materials and products in the chemical industry are hazardous chemicals; hazardous chemicals are flammable Explosive, toxic and harmful, corrosive, radioactive and other characteristics, and most chemical reactions are exothermic reactions, the danger is very huge, once an accident occurs, it will not only cause casualties, property losses, and even bring extreme to the environment. Therefore, in order to reduce or avoid the occurrence of serious accidents such as self-reactive chemical fires and explosions, the research and cognition of chemical reaction processes and thermal hazards of chemical substances are particularly critical.

The thermal runaway process of self-reactive chemicals is usually characterized by high temperature and high pressure and rapid changes in sample components. Adiabatic acceleration calorimeters can truly simulate the exothermic reactions of chemical substances under extreme conditions, and can directly obtain Part of the thermal hazard characteristic parameters of the product under adiabatic conditions is the main test instrument for the study of thermal hazard characteristics; so far, for decades, the research on adiabatic acceleration calorimeters at home and abroad has been developing and progressing continuously, and the development in foreign markets A series of advanced products (ARC of British THT Company, PhiTECⅡ of British Hull Company, APTAC of German NETZSCH Company, VSP2 of American FAI and dARC of American Omnical) have been developed; among them, PhiTECⅡ, APTAC and VSP2 are carried out through the pressure balance system. Pressure compensation, by reducing the pressure difference inside and outside the sample cell, while increasing the sample volume, it can also ensure that the sample cell has a thinner wall thickness, effectively reducing the thermal inertia factor φ, making the safety and danger of hazardous chemicals. However, when testing a sample with a very fast reaction rate, the pressure rise rate of the sample cell is extremely large during the decomposition stage of the violent reaction of the sample, and the pressure compensation technology cannot guarantee the immediate pressure inside and outside the sample cell. In some cases, the sample cell will be broken; therefore, in the development process of the adiabatic acceleration calorimeter, the sample cell is always used as a complete reaction system together with the test sample, and on this basis, the thermal inertia factor is corrected, It is difficult to achieve ideal thermal insulation by adopting pressure compensation technology and changing the structure of the test cell.

At present, the reaction system composed of the sample and the sample cell of the traditional adiabatic acceleration calorimeter does not achieve ideal insulation, and part of the heat released by the sample reaction is absorbed by the sample cell, resulting in a thermal inertia factor φ greater than 1, which affects the thermal hazard. The accuracy of parameter measurement; when the thermal inertia factor φ is greater than 1, the process of the reaction is different from that in the complete adiabatic case, resulting in changes in some kinetic parameters, such as frequency factor, reaction activation energy, and reaction order, which are different from the ideal There are certain deviations in the state, and the reliability of the thermodynamic analysis results is reduced, which affects the process research and development design, risk assessment, and the formulation of self-reactive chemical production, storage and transportation specifications, and finally leads to the emergence of potential safety hazards.

SUMMARY OF THE INVENTION

The invention proposes an adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of the sample cell, which aims to solve the problem that the sample heat is lost due to the reaction heat absorbed by the sample cell, and it is difficult to achieve ideal thermal insulation.

The technical solution of the present invention: an adiabatic acceleration calorimeter based on the temperature measurement of the inner surface of the sample cell, the structure of which includes a sample temperature detection thermocouple 1, a sample cell 2, a sample cell heater, and a sample cell inner surface temperature measurement thermocouple 5; The sample cell heaters include A sample cell wall heater 3, B sample cell wall heater 4, C sample cell wall heater 10, D sample cell wall heater 11, and sample cell bottom heater 6; sample temperature The detection thermocouple 1 is inserted into the sample cell 2 from the upper opening of the sample cell 2. A sample cell wall heater 3, B sample cell wall heater 4, C sample cell wall heater 10, D sample cell wall heater 11 are respectively fixed On the surrounding side walls of the sample cell 2, the heater 6 at the bottom of the sample cell is fixed at the bottom of the sample cell 2, the temperature measurement thermocouple 5 on the inner surface of the sample cell is inserted on the sample cell wall of the sample cell 2, and the temperature measurement thermocouple on the inner surface of the sample cell The end of 5 abuts the inner surface of the sample cell 2 .

Advantages of the present invention:

1) Solve the problem that the sample heat is lost due to the absorption of reaction heat by the sample cell, and it is difficult to achieve ideal thermal insulation;

2) Avoid problems such as deviations in thermal analysis kinetics research and thermal hazard safety assessment due to the absorption of reaction heat by the sample cell;

3) Overcoming the limitation of the traditional adiabatic accelerated calorimetry method, the traditional outer surface of the sample cell is adiabatically advanced to the inner surface of the sample cell. When the temperature change rate of the sample exceeds the set threshold, the sample cell is heated with a heater, and Active temperature compensation eliminates the influence of the heat absorption of the sample cell on the reaction process, so that the sample temperature is equal to the inner surface temperature of the sample cell, and the sample cell is separated from the target reaction system at a certain reaction rate and combined with the sample to form an adiabatic system;

4) The present invention proposes a new method of adiabatic accelerated calorimetry that redefines thermal inertia, proposes an adiabatic factor that is not affected by the sample cell, and can obtain more accurate thermal hazard characteristic parameters of self-reactive chemicals. The factor is defective and cannot meet the requirements of accurate analysis of thermal hazard characteristic parameters, and needs to be redefined. The adiabatic factor is the ratio of the sample heat loss to the reaction heat release, which can be used to replace the thermal inertia factor;

5) The present invention guides the production of self-reactive chemicals, the setting of storage and transportation process parameters and risk assessment, ensures safe operation, reduces the risk of accidents in the hazardous chemical industry, reduces the possibility of catastrophic results caused by thermal runaway effects, and promotes hazardous chemicals. The safe and healthy development of the product industry is of great significance.

Description of drawings

1 is a front sectional view of the sample cell of the adiabatic acceleration calorimeter based on temperature compensation of the present invention.

Fig. 2 is a side sectional view of the sample cell of the adiabatic acceleration calorimeter based on temperature compensation of the present invention.

3 is a schematic diagram of the overall structure of the adiabatic acceleration calorimeter based on temperature compensation of the present invention.

1 is the sample temperature detection thermocouple, 2 is the sample cell, 3 is the A sample cell wall heater, 4 is the B sample cell wall heater, 10 is the C sample cell wall heater, 11 is the D sample cell wall heater 5 is the temperature measuring thermocouple on the inner surface of the sample cell, 6 is the heater at the bottom of the sample cell, 7 is the sample to be tested, 8 is the feeding channel, 9 is the reaction zone, 12 is the reaction zone container, 13 is the opening, and 14 is the measuring hole , 15 is the adiabatic acceleration calorimeter furnace body, 16 is the adiabatic acceleration calorimeter furnace body heater.

Detailed ways

An adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of a sample cell, the structure of which includes a sample temperature detection thermocouple 1, a sample cell 2, a sample cell heater, and a sample cell inner surface temperature measurement thermocouple 5; wherein, the sample cell heating The device includes A sample cell wall heater 3, B sample cell wall heater 4, C sample cell wall heater 10, D sample cell wall heater 11, sample cell bottom heater 6; sample temperature detection thermocouple 1 from the sample cell The upper opening of 2 is inserted into the sample cell 2, A sample cell wall heater 3, B sample cell wall heater 4, C sample cell wall heater 10, D sample cell wall heater 11 are respectively fixed on the surrounding sides of the sample cell 2 On the wall, the heater 6 at the bottom of the sample cell is fixed at the bottom of the sample cell 2, the temperature measuring thermocouple 5 on the inner surface of the sample cell is inserted on the wall of the sample cell 2, and the end of the temperature measuring thermocouple 5 on the inner surface of the sample cell is close to the sample. The inner surface of pool 2.

The adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of the sample pool, its structure also includes a furnace body 15 of the adiabatic acceleration calorimeter, a plurality of heaters 16 of the furnace body of the adiabatic acceleration calorimeter; the sample pool 2, the sample pool heater Located inside the adiabatic acceleration calorimeter furnace body 15 , a plurality of adiabatic acceleration calorimeter furnace body heaters 16 are distributed around the adiabatic acceleration calorimeter furnace body 15 .

The sample pool 2 is cylindrical; the sample pool 2 includes a feeding channel 8 and a reaction zone container 12, the feeding channel 8 is located directly above the reaction zone container 12, and there is an opening 13 directly above the reaction zone container 12. The opening 13 of the reaction zone container 12 is connected, the upper port of the feeding channel 8 is the upper opening of the sample pool 2, the feeding channel 8 and the reaction zone container 12 are both cylindrical, the feeding channel 8 is placed in a vertical direction, and the diameter of the feeding channel 8 smaller than the diameter of the reaction zone vessel 12 .

The feeding channel 8 is placed in a vertical direction, and the feeding channel 8 is located at the center of the top of the reaction zone container 12; during operation, the upper port of the sample temperature detection thermocouple 1 is inserted vertically in the top center of the reaction zone container 12. To the sample cell 2, it is used to realize the accurate measurement of the reaction temperature of the sample.

There is a measuring hole 14 on the side wall or bottom of the reaction zone container 12, the temperature measurement thermocouple 5 on the inner surface of the sample cell is inserted in the measurement hole 14, and the end of the temperature measurement thermocouple 5 on the inner surface of the sample cell is close to the side wall of the sample cell 2. The inner surface of the inner surface of the sample cell or the inner surface of the bottom of the sample cell 2; the diameter of the measuring hole 14 matches the diameter of the temperature measuring thermocouple 5 on the inner surface of the sample cell; during operation, the temperature measuring thermocouple 5 on the inner surface of the sample cell is inserted from the measuring hole 14 until it is tight Adhering to the inner surface of the side wall of the sample cell 2 or the inner surface of the bottom of the sample cell 2, the temperature measuring thermocouple 5 on the inner surface of the sample cell is used to measure the inner surface temperature of the side wall of the sample cell 2 or the inner surface temperature of the bottom of the sample cell 2; preferably On the ground, the measuring hole 14 is located on the side wall of the sample cell 2, the end of the temperature measuring thermocouple 5 on the inner surface of the sample cell is close to the inner surface of the side wall of the sample cell 2, and the sample cell 2 is obtained by measuring the inner surface temperature of the side wall of the sample cell 2. Inner surface temperature; further preferably, there are several measurement holes 14, several measurement holes 14 are respectively located on the side wall of the sample cell 2 and on the bottom of the sample cell 2, and the inner surface temperature measuring thermocouples 5 of several sample cells are respectively inserted in the corresponding measurement In the hole 14, the ends of several sample cell inner surface temperature measuring thermocouples 5 correspond to the inner surface of the side wall of the sample cell 2 or the inner surface of the bottom of the sample cell 2, respectively. The inner surface temperature of the bottom of the cell 2 can be obtained from the inner surface temperature of the sample cell 2, which is convenient to select and control different sample cell heaters through the temperature collected by the temperature measurement thermocouple 5 on the inner surface of the sample cell; the sample temperature detection thermocouple 1 and the sample cell The temperature data collected by the surface temperature measuring thermocouple 5 is displayed and recorded through the control software.

The A sample cell wall heater 3, the B sample cell wall heater 4, the C sample cell wall heater 10, and the D sample cell wall heater 11 are respectively fixed on the front, rear, left and right sides of the surrounding side walls of the sample cell 2. On the outer side walls of the four sides, the sample cell bottom heater 6 is fixed at the center of the bottom outer surface of the sample cell 2; 4. The C sample cell wall heater 10, the D sample cell wall heater 11, and the sample cell bottom heater 6 heat the sample to be tested 7 and the sample cell 2, so that the temperature of the sample to be tested 7 in the sample cell 2 and the inner surface of the sample cell are heated temperature is equal.

The inner cavity of the reaction zone container 12 is the reaction zone 9; during operation, the sample to be tested 7 is placed in the inner cavity of the reaction zone container 12, that is, the sample to be tested 7 is placed in the reaction zone 9, and the temperature of the sample is detected by thermoelectricity. Couple 1 is inserted vertically into the reaction zone 9 from the upper port of the feed channel 8 at the center of the top of the reaction zone vessel 12 .

In the present invention, the sample temperature detection thermocouple 1 is inserted from the middle of the sample cell 2 to measure the temperature of the reaction exothermic temperature of the sample 7 to be tested, and the temperature measurement thermocouple 5 on the inner surface of the sample cell The temperature measurement thermocouple on the inner surface of the sample cell is inserted radially into the measuring hole 14 designed in size 5, and the insertion depth is until it is close to the inner surface of the sample cell 2, which is used to collect the temperature of the inner surface of the sample cell 2; the sample temperature detection thermocouple 1 and The temperature collected by the temperature measurement thermocouple 5 on the inner surface of the sample cell is displayed and recorded by the control software of the measurement and control system.

The sample cell 2 is located in the center of the furnace chamber of the adiabatic acceleration calorimeter furnace body 15 to ensure uniform heating.

The specific working mode of the adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of the sample cell includes the following steps:

Step 1, add the configured sample to be tested 7 to the sample cell 2, insert the sample temperature detection thermocouple 1 into the sample cell 2; preferably, the sample cell 2 is located in the center of the furnace chamber of the adiabatic acceleration calorimeter furnace body 15 to ensure uniformity. heated;

In step 2, the adiabatic acceleration calorimeter is made to perform a dynamic adiabatic calorimetry experiment in the standard heating-waiting-searching (H-W-S) mode through the control software on the computer, the A sample cell wall heater 3, B sample cell wall heating 4, C sample cell wall heater 10, D sample cell wall heater 11, and sample cell bottom heater 6 are used to heat the surrounding of sample cell 2, sample temperature detection thermocouple 1 and sample cell inner surface temperature measurement thermocouple 5 Transfer the temperature of the sample to be tested 7 and the inner surface of the sample pool to the measurement and control system respectively;

Step 3, when it is detected that the self-heating rate of the sample to be tested 7 is higher than the set threshold, the adiabatic acceleration calorimeter enters the adiabatic tracking stage, and the temperature of the sample cell 2 is controlled to track the temperature of the sample cell 2 during the test to perform the exothermic reaction to be tested. The temperature of the sample 7, under a certain reaction rate, makes the temperature of the inner surface of the sample pool 2 equal to the temperature of the sample 7 to be tested in real time, so as to ensure that the sample 7 to be tested performs an exothermic reaction under adiabatic conditions; preferably, the certain reaction rate is Refers to the sample exothermic rate≤200℃/min;

Step 4, when the temperature of the inner surface of the sample cell is equal to the temperature of the sample 7 to be tested, the adiabatic surface is pushed from the outer surface of the sample cell 2 to the inner surface of the sample cell 2. At this time, the sample cell 2 is separated from the reaction system to achieve ideal thermal insulation and make the thermal insulation The factor is equal to 1, the heat dissipation is equal to 0, and its expression is shown in Equation (A):

In formula (A), η _ad is the adiabatic factor, P _lost is the heat dissipation power of the sample, and P _s is the exothermic power of the sample.

The heating-waiting-searching (H-W-S) mode specifically includes the following steps:

Step 1-1, in the heating stage, the adiabatic acceleration calorimeter is heated according to the preset temperature until the preset temperature;

Step 1-2, then enter the waiting stage, after waiting for a period of time, wait until the temperature of the sample to be tested 7 and the adiabatic acceleration calorimeter furnace body 15 reach a uniform equilibrium state, and the test system enters the search mode;

Step 1-3, compare the temperature rise rate of the sample to be tested 7 with the set temperature rise detection threshold; if the temperature rise rate of the sample to be tested 7 is less than the set temperature rise rate threshold, increase the preset temperature value, it will automatically enter the next round of "heating-waiting-search" stage; otherwise, it is judged that the sample is exothermic, the calorimeter will change to "exothermic" mode, stop active heating, and enter the adiabatic tracking stage, where adiabatic tracking In the stage, the measurement and control system adjusts the power of the adiabatic acceleration calorimeter furnace body heater 16 in each region of the adiabatic acceleration calorimeter furnace body 15 according to the temperature difference between the temperature of the sample 7 and the adiabatic acceleration calorimeter furnace body 15, thereby It is ensured that the temperature of the furnace body 15 of the adiabatic acceleration calorimeter is consistent with the temperature of the sample 7 to be tested, so as to realize the adiabaticity of the acceleration calorimeter; the temperature rise detection threshold is preferably set to 0.02°C/min.

The adiabatic tracking stage specifically includes: after the adiabatic acceleration calorimeter enters the adiabatic tracking stage, simultaneously tracking the exothermic state of the sample to be tested 7 in two ways; the two ways of tracking include first-level tracking and second-level tracking; first-level tracking; The tracking is the furnace body heater 16 of the adiabatic acceleration calorimeter to heat the furnace body 15 of the adiabatic acceleration calorimeter, so that the temperature of the furnace body 15 of the adiabatic acceleration calorimeter tracks the temperature of the sample to be tested 7; the secondary tracking is for the sample cell heater to heat the sample cell. The surface temperature of the sample pool tracks the temperature of the sample 7 to be tested; at this time, it is necessary to track the real-time temperature of the sample 7 to be tested through the temperature control unit in the measurement and control system, and try to make the temperature of the adiabatic acceleration calorimeter furnace 15 consistent with the temperature of the sample 7 to be tested and Make the temperature of the inner surface of the sample cell equal to the temperature of the sample 7 to be tested in real time.

The present invention can further carry out temperature control and tracking by adopting the PID algorithm based on fuzzy theory control. The PID algorithm based on fuzzy theory control combines ordinary PID (incremental PID) control and fuzzy control, and the two complement each other. The three important parameters K _p , K _i , K _d of the PID controller are dynamically adjusted according to the conditions of the two variables error e and the error rate of change e _c , so that the performance of the controller can be optimized; in the secondary temperature tracking , the error _e and the error rate of change ec can represent the error and the rate of change of the error between the surface temperature of the sample cell and the measured value of the sample thermocouple.

In order to avoid the absorption of the reaction heat by the sample cell 2 during the reaction of the sample to be tested 7, it is necessary to ensure that when the temperature of the inner surface of the sample cell is equal to the temperature of the sample to be tested 7, A sample cell wall heater 3, B sample cell wall heater 4, C The heat compensated by the sample cell wall heater 10, the D sample cell wall heater 11, and the sample cell bottom heater 6 is equal to the part of the heat absorbed by the sample cell 2 from the sample to be tested 7 during the reaction process, that is, the sample to be tested 7 and the sample cell 2 The heat transfer relationship between needs to be expressed by the energy conservation equation (B):

In formula (B), Q is the heat released by the sample 7 to be tested, P is the total power of the heater, C _s and C _sc are the specific heat capacities of the sample 7 to be tested and the sample cell 2, respectively, M _s and M _sc are the For the mass of the sample 7 and the sample cell 2, T _s and T _sc are the temperatures of the sample 7 to be tested and the inner surface of the sample cell, respectively. At this time, T _s and T _sc are equal.

When there is a temperature difference between the sample to be tested 7 and the inner surface of the sample cell, the heat flow from the sample to be tested 7 to the sample cell 2 is:

In formula (C), S is the contact area between the sample 7 to be tested and the sample cell 2, b is the thickness of the side wall or bottom of the sample cell 2, the side wall and the bottom of the sample cell 2 have the same thickness, and λ is the thermal conductivity of the sample cell 2. coefficients, T _s and T _sc are the temperature of the sample 7 to be tested and the temperature of the inner surface of the sample cell 2, respectively,

The heat flow transferred to the sample cell 2 for the sample 7 to be tested.

The contact area between the sample to be tested 7 and the sample cell 2 is:

S=πR ² +2πRh (D)

In formula (D), R is the inner radius of the sample cell 2 , and h is the height of the sample to be tested 7 in the sample cell 2 .

By controlling the output power P of the sample cell heater to compensate the heat flow loss caused by heat transfer between the sample to be tested 7 and the sample cell 2; the output power P of the sample cell heater should be equal to the heat transfer from the sample to be tested 7 to the sample cell 2 flow, as shown in the following formula (E):

So according to formulas (C, (D) and (E), we can get:

Once the sample to be tested 7 continues to react and exothermic, and the temperature of the sample cell 2 and the sample to be tested 7 deviates, adjust the A sample cell wall heater 3, B sample cell wall heater 4, C sample cell wall heater 10, D. The power of the sample cell wall heater 11 and the sample cell bottom heater 6 is used to adjust the temperature balance between the sample cell 2 and the sample to be tested 7 .

To sum up, an adiabatic acceleration calorimeter based on the temperature measurement of the inner surface of the sample pool proposed by the present invention overcomes the deficiency that the traditional adiabatic acceleration calorimeter design is difficult to achieve ideal adiabatic insulation, and can make the traditional sample pool outside the The surface adiabatic is advanced to the inner surface of the sample cell, and the sample cell 2 is actively fed back and compensated within a certain reaction rate (sample exothermic rate ≤ 200°C/min), so as to eliminate the effect of the sample cell 2 endotherm on the reaction process within a certain reaction rate range. The influence of , the adiabatic factor is equal to 1, so as to realize the ideal adiabatic. It is comprehensively shown that the present invention is of great significance for effectively implementing the reaction safety risk assessment, self-reactive chemical safety assessment and production, storage and transportation, and reducing the probability of accidents.

Claims

An adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of a sample cell, characterized by comprising a sample temperature detection thermocouple (1), a sample cell (2), a sample cell heater, and a temperature measurement thermocouple (5) for the inner surface of the sample cell; Wherein, the sample cell heater includes A sample cell wall heater (3), B sample cell wall heater (4), C sample cell wall heater (10), D sample cell wall heater (11), Cell bottom heater (6); sample temperature detection thermocouple (1) is inserted into the sample cell (2) from the upper opening of the sample cell (2), A sample cell wall heater (3), B sample cell wall heater ( 4) The C sample cell wall heater (10) and the D sample cell wall heater (11) are respectively fixed on the surrounding side walls of the sample cell (2), and the sample cell bottom heater (6) is fixed on the sample cell (2). ), the thermocouple (5) for measuring the temperature on the inner surface of the sample cell is inserted on the wall of the sample cell (2), and the end of the thermocouple (5) for measuring the temperature on the inner surface of the sample cell is close to the inner surface of the sample cell (2). ;

The working mode of the adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of the sample cell includes the following steps:

Step 1, adding the configured sample to be tested (7) into the sample cell (2), and inserting the sample temperature detection thermocouple (1) into the sample cell (2);

In step 2, the adiabatic acceleration calorimeter is made to carry out a dynamic adiabatic calorimetry experiment in the standard heating-waiting-search mode through the control software on the computer, the A sample cell wall heater (3), the B sample cell wall heater (4), C sample cell wall heater (10), D sample cell wall heater (11), and sample cell bottom heater (6) are used to heat the surrounding of the sample cell (2), and the sample temperature detection thermocouple ( 1) and the temperature measuring thermocouple (5) on the inner surface of the sample cell to respectively transmit the temperature of the sample to be measured (7) and the temperature of the inner surface of the sample cell to the measurement and control system;

Step 3, when it is detected that the self-heating rate of the sample to be tested (7) is higher than the set threshold, the adiabatic acceleration calorimeter enters the adiabatic tracking stage, and the temperature tracking of the sample cell (2) is controlled to release heat during the test. The temperature of the reacted sample to be tested (7), under a certain heating rate, the temperature of the inner surface of the sample tank is equal to the temperature of the sample to be tested (7) in real time, to ensure that the sample to be tested (7) performs an exothermic reaction in adiabatic state;

Step 4, when the temperature of the inner surface of the sample cell is equal to the temperature of the sample to be tested (7), the adiabatic surface is pushed from the outer surface of the sample cell (2) to the inner surface of the sample cell (2), at this time the sample cell (2) is removed from the reaction system. separation, to achieve ideal adiabatic, so that the adiabatic factor is equal to 1, and the heat dissipation is equal to 0, and its expression is shown in formula (A):

In formula (A), η ad is the adiabatic factor, P lost is the heat dissipation power of the sample, and P s is the exothermic power of the sample.
An adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of a sample cell according to claim 1, characterized in that the sample cell (2) comprises a feeding channel (8) and a reaction zone container (12), and the feeding channel (8) ) is located just above the reaction zone container (12), there is an opening (13) just above the reaction zone container (12), the lower port of the feeding channel (8) is communicated with the opening (13) of the reaction zone container (12), and the feeding channel ( The upper port of 8) is the upper opening of the sample cell (2), the feeding channel (8) and the reaction zone container (12) are both cylindrical, the feeding channel (8) is placed in a vertical direction, and the diameter of the feeding channel (8) Less than the diameter of the reaction zone vessel (12).
The adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of the sample cell according to claim 2, characterized in that the feeding channel (8) is located at the center of the top of the reaction zone container (12).
The adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of the sample cell according to claim 2, characterized in that a measuring hole (14) is arranged on the side wall or the bottom of the reaction zone container (12), and the inner surface of the sample cell is measured with a measuring hole (14). The thermocouple (5) is inserted into the measuring hole (14), and the end of the thermocouple (5) for measuring the temperature on the inner surface of the sample cell is close to the inner surface of the side wall of the sample cell (2) or the inner surface of the bottom of the sample cell (2) ; The diameter of the measuring hole (14) matches the diameter of the temperature measuring thermocouple (5) on the inner surface of the sample cell; during operation, the temperature measuring thermocouple (5) on the inner surface of the sample cell is inserted from the measuring hole (14) until it is close to the sample The inner surface of the side wall of the cell (2) or the inner surface of the bottom of the sample cell (2), the thermocouple (5) for measuring the temperature of the inner surface of the sample cell (2) is used to measure the inner surface temperature of the side wall of the sample cell (2) or the sample cell (2) The inner surface temperature of the bottom; the temperature data collected by the sample temperature detection thermocouple (1) and the inner surface temperature measurement thermocouple (5) of the sample cell are displayed and recorded through the control software.
An adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of the sample cell according to claim 1, characterized in that the A sample cell wall heater (3), the B sample cell wall heater (4), the C sample cell The wall heater (10) and the D sample cell wall heater (11) are respectively fixed on the outer side walls of the front, rear, left and right sides of the surrounding side walls of the sample cell (2), and the sample cell bottom heater (6) Fixed at the center of the bottom outer surface of the sample cell (2); during operation, through the A sample cell wall heater (3), B sample cell wall heater (4), C sample cell installed around the sample cell (2) The wall heater (10), the D sample cell wall heater (11), and the sample cell bottom heater (6) heat the sample cell (2), so that the temperature of the sample (7) in the sample cell (2) and the sample The surface temperature of the pool is the same.
The adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of the sample cell according to claim 2, characterized in that the inner cavity of the reaction zone container (12) is the reaction zone (9); during operation, the sample to be tested is (7) is placed in the inner cavity of the reaction zone container (12), that is, the sample to be tested (7) is placed in the reaction zone (9), and the sample temperature detection thermocouple (1) is directly connected to the top of the reaction zone container (12). The upper port of the central feed channel (8) is inserted vertically into the reaction zone (9).
The adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of the sample cell according to claim 1, characterized in that it further comprises an adiabatic acceleration calorimeter furnace body (15) and a plurality of adiabatic acceleration calorimeter furnace body heaters (16). ), the sample pool (2) and the sample pool heater are located inside the adiabatic acceleration calorimeter furnace body (15), and several adiabatic acceleration calorimeter furnace body heaters (16) are distributed in the adiabatic acceleration calorimeter furnace body (15). ) around;

The heating-waiting-searching mode specifically includes the following steps:

Step 1-1, in the heating stage, the adiabatic acceleration calorimeter is heated according to the preset temperature until the preset temperature;

Step 1-2, then enter the waiting stage, after waiting for a period of time, wait until the temperature of the sample to be tested (7) and the adiabatic acceleration calorimeter furnace body (15) reach a uniform equilibrium state, and the test system enters the search mode;

Step 1-3, compare the temperature rise rate of the sample to be tested (7) with the set temperature rise detection threshold; if the temperature rise rate of the sample to be tested (7) is less than the set temperature rise rate threshold, then increase the preset temperature rise rate. The set temperature value will automatically enter the next round of "heating-waiting-searching" stage; otherwise, it is determined that the sample to be tested (7) is reacting with exothermic heat, the calorimeter will change to "exothermic" mode, and the active heating will be stopped. Entering the adiabatic tracking phase, in the adiabatic tracking phase, the measurement and control system adjusts each area of the adiabatic acceleration calorimeter furnace body (15) according to the difference between the temperature of the sample to be tested (7) and the temperature of each area of the adiabatic acceleration calorimeter furnace body (15). The power of the furnace body heater (16) of the adiabatic acceleration calorimeter is adjusted, thereby ensuring that the temperature of the furnace body (15) of the adiabatic acceleration calorimeter is consistent with the temperature of the sample to be measured (7), and the adiabaticity of the acceleration calorimeter is realized.
The adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of the sample cell according to claim 7, wherein the adiabatic tracking stage specifically comprises: after the adiabatic acceleration calorimeter enters the adiabatic tracking stage, two methods are performed simultaneously. Tracking the exothermic state of the sample to be tested (7); two tracking methods include primary tracking and secondary tracking; the primary tracking is the furnace body heater of the adiabatic acceleration calorimeter (16) heating the furnace body of the adiabatic acceleration calorimeter ( 15) Make the temperature of the adiabatic acceleration calorimeter furnace body (15) follow the temperature of the sample to be tested (7); the secondary tracking is for the sample cell heater to heat the sample cell (2) so that the inner surface temperature of the sample cell tracks the sample to be tested (7) At this time, it is necessary to track the real-time temperature of the sample to be measured (7) through the temperature control unit in the measurement and control system, and try to make the temperature of the furnace body (15) of the adiabatic acceleration calorimeter consistent with the temperature of the sample to be measured (7) and make the temperature of the sample pool (7). The surface temperature is equal to the temperature of the sample to be tested (7) in real time.
The adiabatic acceleration calorimeter based on the measurement of the inner surface temperature of the sample cell according to claim 1, characterized in that the heat transfer relationship between the sample to be measured (7) and the sample cell (2) needs to pass an energy conservation equation (B) to represent:

In formula (B), Q is the heat released by the sample to be tested (7), P is the total power of the heater, C s and C sc are the specific heat capacities of the sample to be tested (7) and the sample cell (2), respectively, M s and M sc are the mass of the sample to be tested (7) and the sample cell (2), respectively, T s and T sc are the temperatures of the sample to be tested (7) and the inner surface of the sample cell, respectively, at this time, T s and T sc are equal;

When there is a temperature difference between the sample to be tested (7) and the inner surface of the sample cell, the heat flow from the sample to be tested (7) to the sample cell (2) is:

In formula (C), S is the contact area between the sample to be tested (7) and the sample cell (2), b is the thickness of the side wall or bottom of the sample cell (2), and the side wall and bottom of the sample cell (2) have the same thickness , λ is the thermal conductivity of the sample cell (2), T s and T sc are the temperatures of the sample to be tested (7) and the inner surface of the sample cell, respectively,
is the heat flow transferred from the sample to be tested (7) to the sample cell (2);

The contact area between the sample to be tested (7) and the sample cell (2) is:

S=πR 2 +2πRh (D)

In formula (D), R is the inner radius of the sample cell (2), and h is the height of the sample to be tested (7) in the sample cell (2);

By controlling the output power P of the sample cell heater to compensate the heat flow loss caused by heat transfer between the sample to be tested (7) and the sample cell (2); the output power P of the sample cell heater should be equal to the transfer of the sample to be tested (7) The heat flow to the sample cell (2) is given by the following equation (E):

So according to formulas (C), (D) and (E), we can get:

Once the sample to be tested (7) continues to react and exothermic, and the temperature of the sample cell (2) and the sample to be tested (7) deviates, adjust the A sample cell wall heater (3) and the B sample cell wall heater (4). ), C sample cell wall heater (10), D sample cell wall heater (11), and the power of the sample cell bottom heater (6) to adjust the temperature between the sample cell (2) and the sample to be tested (7) balance.