A method and system for grading autocatalytic strength of DSC isothermal mode

Abstract

This invention discloses a method and system for grading and evaluating autocatalytic intensity using DSC isothermal mode. The method calculates the isothermal induction period of the pure reactant and the induction period containing the catalytic product using a DSC test curve simulating an isothermal temperature for the reactant. The isothermal induction period of the pure reactant is the induction period when the initial conversion rate is 0, and the induction period containing the catalytic product is the induction period when the initial conversion rate is a preset value. The isothermal induction period advance ratio is calculated based on the isothermal induction period of the pure reactant and the induction period containing the catalytic product. The autocatalytic intensity of the reactant is then graded based on the isothermal induction period advance ratio and its corresponding threshold. This invention enables rapid quantitative evaluation of autocatalytic intensity under isothermal conditions, providing theoretical basis and methodological support for the safe management and thermal risk classification of hazardous chemicals during isothermal storage.

Description

Technical Field

[0001] This invention relates to the field of hazardous chemical safety, and in particular to a method and system for grading and evaluating the autocatalytic intensity using DSC isotherm mode. Background Technology

[0002] Autocatalytic thermal decomposition is widely observed in the reaction processes of hazardous materials such as energetic materials, organic peroxides, and fine chemicals. Its core characteristic is that the decomposition products can act as catalytically active substances to accelerate the reaction process, causing the reaction rate to increase non-linearly with increasing conversion rate, ultimately inducing thermal runaway accidents. Unlike the monotonically decaying rate characteristics of classic n-order reactions, autocatalytic reactions typically have a significant induction phase: during this phase, the reaction rate is low and the thermal signal is weak, making it difficult to detect using conventional temperature monitoring methods. Once the autocatalytic acceleration phase begins, the reaction rate and exothermic intensity rise sharply in a short period, easily triggering catastrophic accidents such as combustion and explosion, posing severe challenges to chemical production, material storage and transportation, and process safety management. The temperature rise process of autocatalytic reactions under adiabatic conditions is highly sudden, and conventional temperature alarm mechanisms often fail due to response lag, further highlighting the engineering value of accurate identification and quantitative grading of autocatalytic characteristics.

[0003] Existing methods for quantitative characterization and classification of autocatalytic intensity focus on adiabatic conditions. Based on the Perez-Benito model, normalized standard curves are established through numerical simulations under adiabatic conditions. Autocatalytic intensity is then divided into five levels according to the autocatalytic factor value, achieving rapid classification of adiabatic thermal data. However, this method is significantly affected by the thermal inertia of the testing equipment and the thermal history of the sample, and is only applicable to adiabatic assessment scenarios. In addition, some methods, from a thermodynamic and kinetic perspective, propose using the ratio of the initial heat release to the total heat release as a classification index, and establishing a five-level classification system based on the normal distribution 3σ principle. However, this method is also based on adiabatic conditions and cannot be directly applied to engineering scenarios such as isothermal storage and isothermal reactions.

[0004] In fact, chemical storage, isothermal synthesis processes and other scenarios are mostly in near-isothermal environments, and the isothermal induction period is one of the most critical thermal safety parameters in such scenarios. However, the current autocatalytic intensity classification system for isothermal conditions is not yet perfect, and the definitions of autocatalytic factors in different studies differ in reciprocal form, making it difficult to compare classification thresholds horizontally and failing to meet the actual needs of isothermal safety assessment in engineering. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a method and system for grading and evaluating autocatalytic intensity in DSC isothermal mode, so as to achieve rapid quantitative evaluation of autocatalytic intensity under isothermal conditions.

[0006] Technical solution: The present invention provides a method for evaluating the autocatalytic intensity classification in DSC isotherm mode, comprising the following steps:

[0007] For the reactants to be tested, the DSC test curve at simulated isothermal temperature is used to calculate the isothermal induction period of the pure reactants and the induction period containing the catalytic product; the isothermal induction period of the pure reactants is the induction period when the initial conversion rate is 0, and the induction period containing the catalytic product is the induction period when the initial conversion rate is a preset value.

[0008] The advance ratio of isothermal induction period is calculated based on the isothermal induction period of the pure reactants and the induction period containing the catalytic products.

[0009] The autocatalytic strength of the test reactants is graded based on the ratio of the isothermal induction period advance and its corresponding threshold.

[0010] Furthermore, the advance ratio of the isothermal induction period is the relative change rate between the isothermal induction period of the pure reactants and the induction period containing the catalytic product.

[0011] Furthermore, the isothermal induction period is earlier than... The calculation method is as follows:

[0012] ;

[0013] in, Purely for the isothermal induction period of reactants, The induction period containing catalytic products, This is the preset value for the initial conversion rate.

[0014] Furthermore, the initial conversion rate is set to be much less than 1.

[0015] Furthermore, for the reactant to be tested, the threshold for the advance ratio of the isothermal induction period is determined based on the numerical range of the autocatalytic factor at its isothermal temperature.

[0016] Furthermore, the autocatalytic factor Z at isothermal temperature is related to the earlier induction period compared to... The following relationship must be satisfied:

[0017]

[0018] The autocatalytic factor Z at the isothermal temperature was calculated using a simplified Perez-Benito model. The autocatalytic factor Z follows a normal distribution. According to 3... Several Z values ​​are determined in principle, based on the autocatalytic factor Z and the ratio of the isothermal induction period advance. Relationship calculation of several The value is used as a threshold for the isothermal induction period advancement ratio.

[0019] Furthermore, according to 3 Five Z values ​​were determined in principle, based on the autocatalytic factor Z and the ratio of the isothermal induction period advance. Relationship calculation 5 The value, as a threshold for the isothermal induction period advance ratio, divides the autocatalytic intensity into five levels.

[0020] Furthermore, for the reactant to be tested, the dynamic exothermic rate curve is determined according to the Arrhenius equation, the maximum exothermic rate of the peak value is extracted from the dynamic exothermic rate curve, and the isothermal temperature is determined based on the maximum exothermic rate.

[0021] The autocatalytic intensity grading and evaluation system of DSC isotherm mode according to the present invention includes:

[0022] The induction period calculation unit is used to calculate the isothermal induction period of the pure reactant and the induction period containing the catalytic product for the DSC test curve of the reactant under simulated isothermal temperature; the isothermal induction period of the pure reactant is the induction period when the initial conversion rate is 0, and the induction period containing the catalytic product is the induction period when the initial conversion rate is a preset value.

[0023] The isothermal induction period advance ratio calculation unit is used to calculate the isothermal induction period advance ratio based on the isothermal induction period of the pure reactants and the induction period containing the catalytic products.

[0024] The autocatalytic intensity grading unit is used to grade the autocatalytic intensity of the test reactant based on the isothermal induction period advance ratio and its corresponding threshold.

[0025] The computer program product of the present invention includes a computer program that, when executed by a processor, implements the autocatalytic intensity grading evaluation method of the DSC isotherm mode.

[0026] Beneficial effects: This invention first derives an explicit expression for the isothermal induction period through analytical derivation, constructs a dimensionless isothermal induction period advance ratio criterion, and clarifies its single-value mapping relationship with the autocatalytic factor; on this basis, combined with the log-normal distribution statistical characteristics of the autocatalytic factor, a five-level classification system of autocatalytic intensity under isothermal conditions is established, and the induction period advance ratio threshold corresponding to each level is determined through theoretical calculation. Compared with the prior art, the advantages of this invention are: (1) It can realize rapid quantitative assessment of autocatalytic intensity under isothermal conditions, providing theoretical basis and methodological support for the isothermal storage safety management and thermal risk classification of hazardous chemicals. (2) It does not require complete kinetic parameter fitting, and the quantitative determination of autocatalytic intensity can be completed by only two sets of control isothermal DSC tests. The operation process is simple, the results are intuitive and reliable, and it has the feasibility of direct engineering application. (3) It is applicable to different types of hazardous chemicals such as energetic materials and organic peroxides, and can be extended to the thermal safety assessment of various chemical materials with autocatalytic decomposition risks, providing quantitative basis and methodological support for the thermal risk classification and management of chemical material storage and process. Attached Figure Description

[0027] Figure 1 This is a DSC simulation test example of an embodiment of the present invention.

[0028] Figure 2 Z and the V-type extremely strong autocatalytic Z in this embodiment of the invention Two-dimensional relationship diagram.

[0029] Figure 3 Z and the IV-level high autocatalytic region of this invention embodiment Two-dimensional relationship diagram.

[0030] Figure 4 Z and the third-order moderate autocatalysis of the present invention are examples of this invention. Two-dimensional relationship diagram.

[0031] Figure 5 Z and the weaker autocatalytic stage II of this invention are examples of this invention. Two-dimensional relationship diagram.

[0032] Figure 6 Z and the first-order weak autocatalysis of the present invention are examples of this invention. Two-dimensional relationship diagram. Detailed Implementation

[0033] The autocatalytic intensity classification and evaluation method of DSC isotherm mode described in this invention includes the following steps:

[0034] For the reactants to be tested, the DSC test curve at simulated isothermal temperature is used to calculate the isothermal induction period of the pure reactants and the induction period containing the catalytic product; the isothermal induction period of the pure reactants is the induction period when the initial conversion rate is 0, and the induction period containing the catalytic product is the induction period when the initial conversion rate is a preset value.

[0035] The advance ratio of isothermal induction period is calculated based on the isothermal induction period of the pure reactants and the induction period containing the catalytic products.

[0036] The autocatalytic strength of the test reactants is graded based on the ratio of the isothermal induction period advance and its corresponding threshold.

[0037] Specifically, the isothermal induction period is earlier than The relative change rate between the isothermal induction period of the pure reactants and the induction period containing the catalytic product:

[0038]

[0039] in, Purely for the isothermal induction period of reactants, The induction period containing catalytic products, This is the preset value for the initial conversion rate.

[0040] The autocatalytic factor Z and the ratio of the earlier induction period under isothermal conditions The following relationship must be satisfied:

[0041]

[0042] The autocatalytic factor Z at the isothermal temperature was calculated using a simplified Perez-Benito model. The autocatalytic factor Z follows a normal distribution. According to 3... Several Z values ​​are determined in principle, based on the autocatalytic factor Z and the ratio of the isothermal induction period advance. Relationship calculation of several The value is used as a threshold for the isothermal induction period advancement ratio.

[0043] In this embodiment, according to 3 Five Z values ​​were determined in principle, based on the autocatalytic factor Z and the ratio of the isothermal induction period advance. Relationship calculation 5 The value, as a threshold for the isothermal induction period advance ratio, divides the autocatalytic intensity into five levels.

[0044] The following section provides a detailed explanation of the theoretical derivation process of the autocatalytic intensity grading evaluation method of the present invention, which is achieved through the construction of an autocatalytic reaction kinetic model and a grading system.

[0045] (I) Construction of an isothermal autocatalytic kinetic model based on a simplified Perez-Benito model

[0046] Among many autocatalytic reaction models, the Perez-Benito autocatalytic model, based on the Prout-Tompkins model, proposes a model that includes the initial reaction, product formation, and the product undergoing an autocatalytic reaction process. The Perez-Benito model contains two steps: the first step, called the initiation reaction, is a traditional n-order reaction model; the second step in the Perez-Benito model is called the autocatalytic reaction, which describes the process of accelerating the product reaction.

[0047] The two-step reaction model can be represented as:

[0048] Initiation stage (n-order reaction):

[0049] (1)

[0050] Autocatalytic stage:

[0051] (2)

[0052] In the model, X represents the reactant, B represents the product (which also acts as a catalyst); v is the stoichiometric coefficient; and r is the reaction rate. Based on the Arrhenius equation:

[0053] (3)

[0054] in, is the reaction rate of the decomposition reaction, A is the pre-exponential factor, E is the activation energy, R is the ideal gas constant, and T is the reaction temperature.

[0055] The reaction rates of the two steps are respectively and :

[0056] (4)

[0057] (5)

[0058] in, Conversion rate; , , (i=1,2) represent the reaction rate, pre-exponential factor, and activation energy of each step, respectively. Represents the reaction order of each step (i=1,2,3).

[0059] In the Perez-Benito model, its simplified form is when all reaction orders are equal to 1. The simplified Perez-Benito model has good general applicability in a large number of autocatalytic decompositions. This embodiment uses the simplified Perez-Benito model to quantitatively describe the autocatalytic decomposition and its overall reaction rate. It is expressed as follows:

[0060] (6)

[0061] The autocatalytic factor is a parameter describing the rate ratio of the primary initiation reaction to the autocatalytic reaction, and is a core parameter characterizing the intrinsic autocatalytic ability of a substance. For the simplified Perez-Benito model, under isothermal conditions... Then there is an autocatalytic factor Z:

[0062] (7)

[0063] Among them, intermediate parameters , The autocatalytic factor Z ranges from (0,1), and its value is negatively correlated with the autocatalytic strength: the smaller Z is, the higher the relative contribution of the autocatalytic stage, the stronger the autocatalytic effect of the system, and the higher the suddenness and risk of thermal runaway; when At this time, the reaction is approximately an nth-order reaction, and the autocatalytic effect can be ignored.

[0064] Substituting the autocatalytic factor Z into the simplified Perez-Benito model, the overall rate equation under isothermal conditions can be expressed as:

[0065] (8)

[0066] In the formula: , is the characteristic rate constant of the autocatalytic step under isothermal conditions, which determines the overall reaction timescale of the system; This is the reactant consumption term, reflecting the decrease in reactant concentration as the reaction progresses; This is the autocatalytic activity term, which includes both initial initiation activity and reaction-generating catalytic activity, comprehensively reflecting the rate characteristics of autocatalytic reactions.

[0067] In isothermal mode, the reaction time corresponding to the maximum exothermic rate is... This is the isothermal induction period of the reaction, which is also the moment when the reaction rate acceleration is zero, i.e., the second derivative. Differentiating the rate equation, we have:

[0068] (9)

[0069] Due to the reaction process ,make The conversion rate corresponding to the moment of maximum reaction rate can be obtained. :

[0070] (10)

[0071] Equation (10) shows the conversion rate corresponding to the moment when the maximum reaction rate occurs. It is uniquely determined by the autocatalytic factor Z.

[0072] In order to establish the isothermal induction period Compared with the initial conversion rate The explicit relationship with Z is obtained by integrating the rate equation. Separating the variables, we get:

[0073] (11)

[0074] Factor the integral on the left side into fractions, substitute the values, integrate, and simplify to get:

[0075] (12)

[0076] when hour, Substituting into the above equation, we obtain the isothermal induction period. Compared with the initial conversion rate Explicit relationship with autocatalytic factor Z:

[0077] (13)

[0078] in, The initial conversion rate is The isothermal induction period.

[0079] To ensure that τ is a positive real number, the following condition must be met: Right now ,because The initial conversion rate is set to a very small amount, a condition that naturally holds true in typical autocatalytic systems.

[0080] When there is no conversion of reactants in the system, i.e., a pure reactant system... Then we have:

[0081] (14)

[0082] The isothermal induction period with and without products under the initial conditions in the comparison system:

[0083] (15)

[0084] Since the initial conditions in the comparison system include an isothermal induction period with or without products, when hour, Then we have:

[0085] (16)

[0086] The above formula derivation confirms that, in the simplified Perez-Benito autocatalytic model, adding a small amount of product ( The isothermal induction period is systematically shortened. The initially present product B directly increases the onset rate of the autocatalytic step, accelerating the overall reaction. This earlier induction period is direct kinetic evidence of product catalysis. This conclusion does not depend on specific parameters, only on the PB model framework; therefore, changes in the isothermal induction period can serve as a reliable criterion for identifying autocatalytic reactions.

[0087] To eliminate the influence of absolute time scales, its relative change rate is defined as the advance ratio of the isothermal induction period. :

[0088] (17)

[0089] in, Initial conversion rate Isothermal induction period (for pure reactants); The initial conversion rate is The isothermal induction period. This index characterizes the effect of adding initial products. The resulting relative advance induction period ranges from 0 to 100%. The larger the value, the stronger the accelerating effect of the trace product on the reaction process, that is, the higher the autocatalytic strength of the substance.

[0090] (18)

[0091] Given an initial product addition amount Under certain conditions (such as uniformly fixed at 0.01, 0.02, or 0.05), It is merely a univariate function of the autocatalytic factor Z, a monotonic mapping between it and the autocatalytic intensity. It decreases strictly monotonically with increasing autocatalytic factor Z. All other kinetic parameters ( , , , All of these are indirectly affected through Z. .

[0092] When the autocatalytic strength is strong, Z approaches 0. Therefore Even trace amounts of product can significantly advance the induction period, and the reaction is almost entirely controlled by autocatalysis; when the autocatalytic strength is weak, Z is relatively large, but still satisfies , The smaller value indicates that the catalytic effect of the product is not significant, and the reaction kinetics are closer to an n-order reaction.

[0093] Formula (18) proves that the ratio of the advance of the isothermal induction period can be used as a quantitative criterion for the intensity of autocatalysis, and can intuitively reflect the suddenness and risk of thermal runaway of autocatalytic reaction.

[0094] (II) Construction of a five-level autocatalytic intensity classification system

[0095] The autocatalytic strength of the thermal decomposition of hazardous chemicals is affected by their decomposition kinetic parameters, including the autocatalytic factor. The value of spans multiple orders of magnitude, as shown in formula (7). Common logarithmic form Follows a normal distribution This distribution can reasonably describe the statistical regularity of the autocatalytic intensity of chemical materials.

[0096] Based on the statistical characteristics of a large sample of hazardous chemicals, and combined with the measured range of the autocatalytic factor, the distribution parameters are determined as follows: mean ,correspond The geometric mean is , representing a moderate level of autocatalysis; standard deviation ,correspond The geometric standard deviation is This represents a fluctuation range of one order of magnitude. This parameter system can cover the entire range from low to extremely strong autocatalysis, and is highly compatible with actual engineering conditions.

[0097] assumed , in normal distribution , Using the quantile sites as the core boundary, the autocatalytic intensity was divided into five levels, I to V, from low to high, corresponding to five Z values. When Z values ​​were 0.0001, 0.001, 0.01, 0.1, and 1, respectively, the autocatalytic intensity was further... Substituting the values ​​sequentially, the calculated isothermal induction period advance ratios for each level boundary were 50.2%, 34.9%, 15.3%, 4.6%, and 0%, respectively. Based on these calculations, a five-level classification standard for autocatalytic intensity was obtained, as shown in Table 1. This classification system achieves a complete quantitative correlation between "statistical distribution - intrinsic autocatalytic parameters - thermal safety criteria - risk level," and can be directly used for the rapid determination of autocatalytic intensity and thermal risk classification of substances.

[0098] Table 1. Five-level classification standard for autocatalytic intensity and thermal runaway risk.

[0099]

[0100] The classification system of this invention is applicable to hazardous chemical systems in which the DSC curve under isothermal mode exhibits a distinct bell-shaped peak, corresponding to significant autocatalytic characteristics and a clear isothermal induction period.

[0101] The effectiveness of the isothermal induction period advance ratio criterion and the five-level classification system of the present invention is verified by numerical simulation experiments below.

[0102] The numerical simulation experiments in this embodiment are based on a simplified Perez-Benito dynamics model, and perform batch numerical simulations covering different pre-exponential factors. , ,activation energy , For example, calories , The data were combined to generate a total of 144 sets of complete dynamic data, with specific parameters shown in Table 2.

[0103] Table 2 Numerical Simulation Parameter Design

[0104]

[0105] The procedure for the numerical simulation experiment is as follows:

[0106] (1) For a given set of , , , Substitute into equation (6) to calculate the autocatalytic factor Z;

[0107] (2) The isothermal evaluation temperature is obtained by using dynamic DSC mode, and the heating rate is set by standardization procedure. ,Will , , , Substituting into the Arrhenius equation, the dynamic heat release rate curve is obtained, and the peak maximum heat release rate is extracted from the curve. Define isothermal temperature The heat release rate on the dynamic curve is equal to The corresponding thermodynamic temperature;

[0108] (3) The simulated isothermal temperature is DSC test curves were used to calculate the isothermal induction period of pure reactants. ( );

[0109] (4) Fix the initial trace product The simulated isothermal temperature is DSC test curves were used to calculate the induction period of the catalytic product. ;

[0110] (5) , Substituting into equation (17), we can solve for the advance ratio of the isothermal induction period. .

[0111] Based on the above steps, for 144 sets of simulated samples, according to Determine the type of reaction curve by selecting the appropriate value: The isothermal exothermic curve exhibits a typical bell shape, first rising and then falling, indicating an effective autocatalytic sample. The isothermal exothermic rate monotonically decays with no peak value, classifying it as a pure n-order reaction and not participating in the fractional statistics. In the 144 simulated samples, some... The isothermal curves of the groups do not exhibit bell-shaped heat release characteristics, but only show a monotonic decay trend, which is inconsistent with the theoretical derivation. The conclusion that the reaction is of order n is completely consistent; this data is only used as a control sample and is not included in the five-level graded verification dataset. All remaining valid autocatalytic samples meet the requirements. The isothermal exothermic curve exhibits a clear rate peak, which can be used to verify the relationship between Z and... The monotonic correspondence and the rationality of the hierarchical threshold.

[0112] The numerical simulation results are as follows:

[0113] Of the 144 simulated samples, 8 were tested. Regardless of changes in the pre-exponential factor and activation energy, the isothermal exothermic rate curve showed no rising segment; the reaction rate continuously decreased over time, with no induced acceleration process, and the kinetic behavior was completely consistent with classical n-order decomposition. These eight sets of data also demonstrate that although the chosen Prout–Tompkins model is an autocatalytic model, it can still describe n-order reactions by changing parameter settings. (Simulation in progress) All groups

[0114] In the remaining 136 sample groups, the isothermal test curves all showed bell-shaped peaks, which can be identified as autocatalytic reactions, and the addition of trace amounts of products... During this period, the isothermal induction period was shifted forward to varying degrees, see Figure 1 Simulated test examples, Figure 1 (a) in the figure is determined by DSC dynamic simulation. A schematic diagram, Figure 1 (b) in the figure is determined by DSC isothermal simulation. , A schematic diagram, Figure 1 The dynamic parameters set in the middle are: , ,, , .

[0115] To verify Z and The monotonic correspondence was analyzed, and 136 sets of simulated autocatalytic effective data were compiled and extracted from each set. Two-dimensional data point plotting analysis can yield a strictly monotonically decreasing curve, see... Figures 2-6 Z and Numerical simulation results show that as the autocatalytic factor Z increases, the isothermal induction period is advanced compared to... The monotonicity of the theory of perfect matching (18) continues to decrease.

[0116] Figure 2 It is a Class V extremely strong autocatalyst ( Z and Two-dimensional relationship diagram Figure 3 It is a Class IV high autocatalytic region ( Z and Two-dimensional relationship diagram Figure 4 For Class III moderate autocatalysis ( Z and Two-dimensional relationship diagram Figure 5 It is a weaker type II autocatalysis ( Z and Two-dimensional relationship diagram Figure 6 It is a weak autocatalysis of order I. Z and Two-dimensional relationship diagram.

[0117] Combination Figure 2 It can be known that:

[0118] 1. When Interval samples: All correspondences It is classified as a Class V strong autocatalysis;

[0119] 2. Interval samples, It remained stable at 34.9%~50.2%, matching the strong autocatalytic range of Grade IV;

[0120] 3. All simulation points, Concentrated between 15.3% and 34.9%, corresponding to moderate autocatalysis in Stage III;

[0121] 4. The calculated percentages for each group ranged from 4.6% to 15.3%, classifying it as a relatively weak autocatalytic group (Class II).

[0122] 5. Effective autocatalytic samples, Between 0% and 4.6%, it falls within the range of Class I weak autocatalysis.

[0123] All valid simulated samples The coordinate points strictly lie on the theoretically derived single-valued function curve, with no discrete outliers, proving that the isothermal induction period advancement criterion in this paper has a unique and stable quantitative mapping relationship, unaffected by... , , , The combination of kinetic parameters is disturbed and determined solely by the autocatalytic factor Z.

[0124] Based on the above analysis, the following conclusions can be drawn:

[0125] 1. The results of 144 batch numerical simulations show that the five-level classification boundary points derived in this embodiment are... corresponding The thresholds (50.2%, 34.9%, 15.3%, 4.6%, 0%) can accurately divide different autocatalytic intensity ranges, and there is no cross-range discrete data under each combination of kinetic parameters;

[0126] 2. Isothermal temperature The standardized selection method of temperature corresponding to one percent of the peak heat flux of dynamic DSC is adopted to eliminate the evaluation bias caused by the artificial setting of isothermal temperature, and the classification results have universality.

[0127] 3. The curve shape discrimination result is completely consistent with the Z-interval division. The sample was isothermal and had no bell-shaped peak, indicating an nth-order reaction, which supports the reasonable definition of the applicable scope of the grading system.

[0128] 4. Overall simulation data proves that the five-level quantitative classification system based on the isothermal induction period advance ratio has a rigorous theoretical derivation and stable numerical law, and can be used for quantitative assessment of the autocatalytic intensity and thermal runaway risk classification of hazardous chemicals with different kinetic characteristics.

[0129] The autocatalytic intensity grading and evaluation system of DSC isotherm mode described in this invention includes:

[0130] The induction period calculation unit is used to calculate the isothermal induction period of the pure reactant and the induction period containing the catalytic product for the DSC test curve of the reactant under simulated isothermal temperature; the isothermal induction period of the pure reactant is the induction period when the initial conversion rate is 0, and the induction period containing the catalytic product is the induction period when the initial conversion rate is a preset value.

[0131] The isothermal induction period advance ratio calculation unit is used to calculate the isothermal induction period advance ratio based on the isothermal induction period of the pure reactants and the induction period containing the catalytic products.

[0132] The autocatalytic intensity grading unit is used to grade the autocatalytic intensity of the test reactant based on the isothermal induction period advance ratio and its corresponding threshold.

Claims

1. A method for grading and evaluating the autocatalytic intensity in DSC isotherm mode, characterized in that, Includes the following steps: For the reactants to be tested, the DSC test curve at simulated isothermal temperature is used to calculate the isothermal induction period of the pure reactants and the induction period containing the catalytic product; the isothermal induction period of the pure reactants is the induction period when the initial conversion rate is 0, and the induction period containing the catalytic product is the induction period when the initial conversion rate is a preset value. The advance ratio of isothermal induction period is calculated based on the isothermal induction period of the pure reactants and the induction period containing the catalytic products. The autocatalytic strength of the test reactants is graded based on the ratio of the isothermal induction period advance and its corresponding threshold.

2. The method for grading and evaluating the autocatalytic intensity in DSC isotherm mode according to claim 1, characterized in that, The advance ratio of the isothermal induction period is the relative change rate between the isothermal induction period of the pure reactants and the induction period containing the catalytic product.

3. The method for grading and evaluating the autocatalytic intensity in DSC isotherm mode according to claim 2, characterized in that, The isothermal induction period is earlier than The calculation method is as follows: ； in, Purely for the isothermal induction period of reactants, The induction period containing catalytic products, This is the preset value for the initial conversion rate.

4. The method for grading and evaluating the autocatalytic intensity in DSC isotherm mode according to claim 1 or 3, characterized in that, The initial conversion rate is set to be much less than 1.

5. The method for grading and evaluating the autocatalytic intensity in DSC isotherm mode according to claim 1, characterized in that, For the reactant to be tested, the threshold of the advance ratio of the isothermal induction period is determined based on the numerical range of the autocatalytic factor at its isothermal temperature.

6. The method for grading and evaluating the autocatalytic intensity in DSC isotherm mode according to claim 5, characterized in that, The autocatalytic factor Z and the ratio of the earlier induction period under isothermal conditions The following relationship must be satisfied: The autocatalytic factor Z at the isothermal temperature was calculated using a simplified Perez-Benito model. The autocatalytic factor Z follows a normal distribution. According to 3... Several Z values ​​are determined in principle, based on the autocatalytic factor Z and the ratio of the isothermal induction period advance. Relationship calculation of several The value is used as a threshold for the isothermal induction period advancement ratio.

7. The method for grading and evaluating the autocatalytic intensity in DSC isotherm mode according to claim 6, characterized in that, According to 3 Five Z values ​​were determined in principle, based on the autocatalytic factor Z and the ratio of the isothermal induction period advance. Relationship calculation 5 The value, as a threshold for the isothermal induction period advance ratio, divides the autocatalytic intensity into five levels.

8. The method for grading and evaluating the autocatalytic intensity in DSC isotherm mode according to claim 1, characterized in that, For the reactant to be tested, the dynamic exothermic rate curve is determined according to the Arrhenius equation, the maximum exothermic rate of the peak value is extracted from the dynamic exothermic rate curve, and the isothermal temperature is determined according to the maximum exothermic rate.

9. A DSC isotherm-based autocatalytic intensity grading and evaluation system, characterized in that, include: The induction period calculation unit is used to calculate the isothermal induction period of the pure reactant and the induction period containing the catalytic product for the DSC test curve of the reactant under simulated isothermal temperature; the isothermal induction period of the pure reactant is the induction period when the initial conversion rate is 0, and the induction period containing the catalytic product is the induction period when the initial conversion rate is a preset value. The isothermal induction period advance ratio calculation unit is used to calculate the isothermal induction period advance ratio based on the isothermal induction period of the pure reactants and the induction period containing the catalytic products. The autocatalytic intensity grading unit is used to grade the autocatalytic intensity of the test reactant based on the isothermal induction period advance ratio and its corresponding threshold.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the autocatalytic intensity grading evaluation method of the DSC isotherm mode according to any one of claims 1-8.

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