Thermal risk assessment method for fine chemical distillation process

Abstract

The invention discloses a thermal risk assessment method for a fine chemical distillation process, and relates to the technical field of chemical risk assessment. The method comprises the following steps: acquiring a process temperature upper limit Tp of a to-be-evaluated distillation process, distilling to-be-distilled materials involved in the to-be-evaluated distillation process, selecting materials with different concentrations in each distillation stage to carry out a thermal stability screening test, and carrying out combined test research on the materials with high dangerous concentrations to obtain the thermal stability of the materials. The combined test research means comprise differential scanning calorimetry, pressure tracking differential scanning calorimetry, rapid screening calorimetry, adiabatic calorimetry and microcalorimetry, decomposition kinetics analysis is further carried out, the temperature TD24 corresponding to the maximum reaction rate reaching time of 24 h under the adiabatic condition is obtained, and the thermal safety risk of the distillation process is evaluated with TD24 and Tp as evaluation criteria. The risk of thermal runaway in the distillation process can be effectively prevented and controlled.

Description

Technical Field

[0001] The invention relates to the technical field of chemical risk assessment, and in particular to a thermal risk assessment method for a fine chemical distillation process. Background Art

[0002] The level of fine chemical rate has become one of the main indicators to measure the level of chemical development in a country or region. With economic development and scientific and technological progress, the world's fine chemical level has entered a mature stage. Although the fine chemical industry has made great progress in recent years, we must face up to the fact that there are still many outstanding problems. The industry is still dominated by small and medium-sized enterprises, with a low overall intrinsic safety level, weak safety risk management capabilities for high-risk chemicals and high-risk processes, low automation control levels in fine chemical enterprises, and a large number of workers in high-risk places.

[0003] As a separation unit commonly found in fine chemical enterprises, the distillation unit plays an irreplaceable role in the chemical production process. The evaluation of the distillation unit is of great significance. However, there is little research on thermal risk assessment of the distillation process at home and abroad.

[0004] Therefore, how to provide a thermal risk assessment method for fine chemical distillation process to solve the difficulties existing in the prior art is an urgent problem that technicians in this field need to solve. Summary of the invention

[0005] In view of this, the present invention provides a thermal risk assessment method for a fine chemical distillation process, which provides a scientific basis for how to carry out the assessment of the fine chemical distillation process.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for thermal risk assessment of a fine chemical distillation process comprises the following steps:

[0008] S1. Obtain the upper temperature limit T of the distillation process to be evaluated p ;

[0009] S2. Distill the materials to be distilled involved in the distillation process to be evaluated, select materials of different concentrations at each stage of distillation for thermal stability screening test, and take materials with high concentrations of danger for joint testing and research to obtain their thermal stability. The joint testing and research methods include differential scanning calorimetry, pressure tracking differential scanning calorimetry, rapid screening calorimetry, adiabatic calorimetry, and microcalorimetry;

[0010] S3. Perform decomposition kinetics analysis on dangerous high-concentration materials to obtain the temperature T corresponding to the maximum reaction rate reaching time of 24h under adiabatic conditions. D24 ;

[0011] S4, T D24and T p As an evaluation benchmark, the thermal safety risks of the distillation process are assessed.

[0012] Optionally, S2 includes selecting no less than 3 distillation materials with different concentration gradients for differential scanning calorimetry, pressure tracking differential scanning calorimetry or microcalorimetry to cover the entire distillation process.

[0013] Optionally, in the combined testing study in S2, thermal stability screening data is obtained by testing at the milligram to gram level based on material characteristics;

[0014] For homogeneous materials, thermal stability screening data is obtained using milligram-level testing methods;

[0015] For heterogeneous mixed materials, thermal stability screening data is obtained using gram-level testing methods.

[0016] Optionally, in S2, materials with high concentrations of dangerous substances are selected for rapid screening calorimetry and adiabatic calorimetry to obtain thermal stability data including the initial exothermic decomposition temperature and the decomposition heat release.

[0017] Optionally, obtaining the maximum reaction rate reaching time under adiabatic conditions in S3 includes: obtaining a relationship curve between the maximum reaction rate reaching time and temperature in the thermal decomposition process of the material through decomposition kinetics analysis.

[0018] Optional, S4 in T D24 and T p The evaluation criteria include:

[0019] When T p ≤T D24 When the thermal safety risk of the distillation process is considered acceptable;

[0020] When T p >T D24 The thermal safety risk of the distillation process is considered unacceptable.

[0021] It can be seen from the above technical solution that compared with the prior art, the present invention provides a thermal risk assessment method for a fine chemical distillation process, which has the following beneficial effects: 1) The present invention fully considers the influence of distillation temperature and distillation time on the distillation process, and evaluates the safety of the distillation process in combination with the thermal runaway explosion time; 2) The method of the present invention is suitable for intermittent, semi-batch steaming / distillation, and continuous kettle steaming / distillation processes, filling the gap in thermal risk research and assessment methods for distillation processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0023] Figure 1 A flow chart of a thermal risk assessment method for a fine chemical distillation process disclosed in the present invention;

[0024] Figure 2 The material A decomposition reaction TMR disclosed in the present invention ad Graphs;

[0025] Figure 3 The present invention discloses the self-decomposition reaction TMR of olefinic aldehyde waste liquid ad Graphs;

[0026] Figure 4 The distillation end point system residue self-decomposition reaction TMR disclosed by the present invention ad Graph. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Reference Figure 1 As shown, the present invention discloses a method for thermal risk assessment of a fine chemical distillation process, comprising the following steps:

[0029] S1. Obtain the upper temperature limit T of the distillation process to be evaluated p ;

[0030] S2. Distill the materials to be distilled involved in the distillation process to be evaluated, select materials of different concentrations at each stage of distillation for thermal stability screening test, and conduct joint testing and research on materials with high dangerous concentrations to obtain their thermal stability. The joint testing and research methods include differential scanning calorimetry, pressure tracking differential scanning calorimetry, rapid screening calorimetry, adiabatic calorimetry, and microcalorimetry;

[0031] S3. Perform decomposition kinetics analysis on dangerous high-concentration materials to obtain the temperature T corresponding to the maximum reaction rate reaching time of 24h under adiabatic conditions. D24 ;

[0032] S4, T D24 and T p As an evaluation benchmark, the thermal safety risks of the distillation process are assessed.

[0033] Further, the test methods are shown in GB / T 22232, GB / T 13464 and SN / T 3078.1.

[0034] Furthermore, S2 includes selecting no less than 3 distillation materials with different concentration gradients for differential scanning calorimetry, pressure tracking differential scanning calorimetry or microcalorimetry to cover the entire distillation process.

[0035] Specifically, from the beginning to the end of distillation, the composition and content of the materials in the distillation system are constantly changing, so it is necessary to master the thermal stability of the materials at each stage of the entire distillation system. In order to reduce the number of tests and take into account the safety of the materials in the entire distillation process, 4 materials with different concentrations are selected for thermal stability screening tests, and the concentration gradient is selected as follows: the temperature to be distilled, the residue in the kettle after 33% of the distillation fraction is distilled, the residue in the kettle after 66% of the distillation fraction is distilled, and the residue in the kettle at the end of distillation.

[0036] Furthermore, in the combined testing study in S2, thermal stability screening data were obtained by testing at the milligram to gram level based on material characteristics;

[0037] For homogeneous materials, thermal stability screening data are obtained using milligram-level testing methods, such as differential scanning calorimetry;

[0038] For heterogeneous mixed materials, thermal stability screening data are obtained using gram-level testing methods, such as pressure-tracked differential scanning calorimetry and microcalorimetry (C80).

[0039] Furthermore, in S2, materials with high concentrations of dangerous substances are selected for rapid screening calorimetry and adiabatic calorimetry to obtain thermal stability data including the initial exothermic decomposition temperature and the decomposition heat release.

[0040] Furthermore, when using differential scanning calorimetry, pressure tracking differential scanning calorimetry or microcalorimetry for thermal stability screening tests, the heating rate is usually 1 to 5 K / min, and the upper limit of the test temperature is 300°C. If the upper limit of the process temperature of the distillation process is higher than 200°C, then the upper limit of the sample test temperature is 100°C above the upper limit of the distillation process temperature. If no exotherm is detected in the sample during the test, the residue in the distillation endpoint system is selected as the most dangerous material for rapid screening calorimetry and adiabatic calorimetry testing. The upper limit of the test temperature is selected with reference to the differential scanning calorimetry test.

[0041] Furthermore, obtaining the maximum reaction rate arrival time under adiabatic conditions in S3 includes: obtaining a relationship curve between the maximum reaction rate arrival time and temperature in the thermal decomposition process of the material through decomposition kinetics analysis. For specific methods, refer to the national standard GB / T42300-2022.

[0042] Furthermore, for undecomposed materials,

[0043] T D24 >T z -100,

[0044] Among them, T z It is adiabatic tracking of the upper limit temperature of decomposition, in °C.

[0045] Further, referring to Table 1, T in S4 D24 and T p The evaluation criteria include:

[0046] When T p ≤T D24 When the thermal safety risk of the distillation process is considered acceptable;

[0047] When T p >T D24 The thermal safety risk of the distillation process is considered unacceptable.

[0048] Table 1 Thermal safety risk assessment standards for distillation process

[0049]

[0050] In one embodiment,

[0051] 1) Process description: Material A is distilled to obtain the residue B and fraction C in the kettle. The distillation temperature is 160-166°C, the pressure is -0.07Mpa, the distillation time is 8h, and the distillation ratio is 70%.

[0052] 2) Testing process

[0053] a. According to the distillation process, four points, A, D (residue after distilling 33% of the fraction), E (residue after distilling 66% of the fraction), and B, were selected for thermal stability screening test. The results are shown in Table 2.

[0054] Table 2 Thermal stability screening test results data table

[0055] No. Sample name Onset exothermic temperature (℃) Heat release (J / g) 1 A 326.3 1173.3 2 D 337.3 1569.2 3 E 340.2 2235.7 4 B 382.7 3453.4

[0056] The differential scanning calorimetry test results show that A has an exothermic signal at 326.3℃, and the sample releases 1173.3J / g (based on sample mass, the same below) in the range of 326.3-441.4℃; D has an exothermic signal at 337.3℃, and the sample releases 1569.2J / g in the range of 337.3-445.3℃; E has an exothermic signal at 340.2℃, and the sample releases 2235.7J / g in the range of 340.2-436.8℃; B has an exothermic signal at 382.7℃, and the sample releases 3453.4J / g in the range of 382.7-460.1℃.

[0057] b. According to the thermal stability screening results, material A has the lowest decomposition temperature and the highest risk. Therefore, material A is selected to carry out thermal stability testing. The experimental results are shown in Table 3.

[0058] Table 3 Insulation test results data table

[0059] Test Information Test conditions Sample name A Testing atmosphere Air Sample amount / g 1.8208 Phi 2.73 Initial outgassing temperature / ℃ 315.7 Initial exothermic temperature / ℃ 315.7 Heat release / (J / g) 1210 Maximum temperature rise rate / (℃ / min) 2811.8 Maximum pressure rise rate / (MPa / min) 416.8

[0060] The results of adiabatic calorimetry test show that the sample undergoes exothermic decomposition at 315.7°C, and the temperature and pressure of the system rise rapidly. When the sample self-exothermically heats up to about 330°C, the temperature and pressure of the system rise sharply, and the decomposition process of the sample intensifies. Within the test range of 315.7-537.6°C, the heat released by decomposition of the sample is 1210 J / g (based on the mass of the sample), the temperature rises by 221.9°C, and the maximum temperature rise rate reaches 2811.8°C / min at 430.4°C, and the maximum pressure rise rate reaches 416.8 MPa / min at 430.4°C.

[0061] c. Using the combined testing method of differential scanning calorimetry, rapid screening calorimetry, and adiabatic accelerated calorimetry, further decomposition kinetics research was carried out to obtain the decomposition thermodynamics and decomposition kinetics data of material A.

[0062] The joint test results show that the initial exothermic decomposition temperature of A is 281.9°C, the decomposition heat is 3270J / g (based on sample mass), and during the decomposition process, the maximum temperature rise rate is 2811.8°C / min, and the maximum pressure rise rate is 416.8MPa / min.

[0063] Through kinetic research and analysis, the relationship curve between the time and temperature of the maximum reaction rate of material A during thermal decomposition is obtained. Figure 2 As shown, under adiabatic conditions, the T of material A D24 It is 214.6℃.

[0064] 3) Thermal safety risk assessment of distillation process

[0065] T of material A D24is 214.6℃, the highest distillation temperature of process A is 166℃, T b ≤T D24 , which is an acceptable risk. Therefore, the possibility of thermal runaway risk in A is not high, and there is enough time for human beings to deal with thermal runaway.

[0066] In another embodiment,

[0067] 1) Process description: A certain olefinic aldehyde waste liquid is distilled to recover olefinic aldehyde, atmospheric distillation, distillation temperature is 110℃, distillation time is 6h, fraction is olefinic aldehyde, fraction distillation ratio is 30%.

[0068] 2) Testing process

[0069] a. According to the distillation process, four points were selected for thermal stability screening test, including olefinic aldehyde waste liquid, the residue after 33% fraction of olefinic aldehyde waste liquid was distilled out, the residue after 66% fraction of olefinic aldehyde waste liquid was distilled out, and the residue of the distillation end point system. The results are shown in Table 4, and the data in the table are the results of differential scanning calorimetry tests.

[0070] Table 4 Test results data table

[0071]

[0072] The differential scanning calorimetry test results showed that within the test range of 350°C, the olefinic aldehyde waste liquid produced an exothermic signal at 183.3°C, and the sample underwent exothermic decomposition. Within the test range of 183.3°C to 312.9°C, the sample released 542.9 J / g of heat. When the temperature was subsequently raised to 350°C, the sample had no obvious exothermic signal.

[0073] Within the test range of 350℃, after 33% of the olefinic aldehyde waste liquid was evaporated, the residue produced an exothermic signal at 185.9℃, and the sample underwent exothermic decomposition. Within the test range of 185.9℃~336.0℃, the sample released 292.4J / g of heat. When the temperature was subsequently raised to 350℃, the sample had no obvious exothermic signal.

[0074] Within the test range of 350℃, after 66% of the olefinic aldehyde waste liquid was evaporated, the residue had no obvious endothermic or exothermic signal.

[0075] Within the test range of 350℃, there is no obvious endothermic or exothermic signal in the residue of the system at the end point of distillation.

[0076] b. According to the thermal stability screening results, the initial exothermic decomposition temperature of the olefinic aldehyde waste liquid is the lowest and the heat release is the largest. Therefore, the olefinic aldehyde waste liquid is selected to carry out the thermal stability test. The experimental results are shown in Table 5.

[0077] Table 5 Material stability information

[0078] Test Information Test conditions and results Sample name Olefin aldehyde waste liquid Sample amount / g 2.2931 Testing atmosphere Nitrogen Phi 2.37 Initial outgassing temperature / ℃ 131.8 Initial exothermic decomposition temperature / ℃ 131.8 Decomposition heat / (J / g) 570 Maximum temperature rise rate / (℃ / min) 1.2 Maximum pressure rise rate / (MPa / min) 0.04

[0079] The results of adiabatic calorimetry test showed that the sample began to have obvious exothermic signals at 131.8℃, the sample underwent exothermic decomposition, and the temperature and pressure of the system rose rapidly. Within the test range of 131.8℃ to 251.3℃, the heat released was 570J / g (based on sample mass), the temperature rose by 119.6℃, the maximum temperature rise rate reached 1.2℃ / min at 213.2℃, and the maximum pressure rise rate reached 0.04MPa / min at 249.0℃.

[0080] c. Using the combined testing method of differential scanning calorimetry, rapid screening calorimetry, and adiabatic accelerated calorimetry, further decomposition kinetics research was carried out to obtain the decomposition thermodynamics and decomposition kinetics data of olefinic aldehyde waste liquid.

[0081] The joint test results show that the initial exothermic decomposition temperature of olefinic aldehyde waste liquid is 131.8°C, the decomposition heat is 570J / g (based on sample mass), and during the decomposition process, the maximum temperature rise rate is 1.2°C / min, and the maximum pressure rise rate is 0.04MPa / min.

[0082] Through kinetic analysis, the relationship curve between the time and temperature of the maximum reaction rate in the thermal decomposition process of olefinic aldehyde waste liquid was obtained. Figure 3 As shown in the figure, under adiabatic conditions, the T D24 It is 106.1℃.

[0083] 3) Thermal safety risk assessment of distillation process

[0084] T of olefin wastewater D24 is 106.1℃, the highest distillation temperature of the olefinic aldehyde waste liquid involved in the process is 110℃, T b >T D24 , which is an unacceptable risk. Therefore, the possibility of thermal runaway risk in the distillation process of a certain olefinic aldehyde waste liquid is high. It is recommended to use vacuum distillation to reduce the distillation temperature so that the distillation temperature is not higher than T D24 , thereby reducing the risk of thermal runaway.

[0085] In another embodiment,

[0086] 1) Process description: After the synthesis reaction of a certain oxime ether is completed, the solvent is removed at normal pressure until the temperature in the reactor is 85°C, the distillation time is 5 hours, the fraction is the solvent, and the distillation ratio of the fraction is 80%.

[0087] 2) Testing process

[0088] a. According to the distillation process, four points were selected for thermal stability screening test, including oxime ether synthesis liquid, the residue after 33% fraction of oxime ether synthesis liquid was distilled out, the residue after 66% fraction of oxime ether synthesis liquid was distilled out, and the residue of the distillation end point system. The results are shown in Table 6.

[0089] Table 6 Thermal stability screening test results data table

[0090]

[0091] The differential scanning calorimetry test results show that the oxime ether synthesis liquid generates an exothermic signal at 163.5°C, and in the range of 163.5 to 237.4°C, the sample releases 108.0 J / g (based on sample mass, the same below).

[0092] After 33% of the oxime ether synthesis liquid was evaporated, the residue produced an endothermic signal at 49.0°C, and in the range of 49.0-66.9°C, the sample absorbed 29.3 J / g of heat. When the temperature continued to rise to 152.9°C, an exothermic signal was produced, and in the test range of 152.9-252.8°C, the heat released was 109.2 J / g.

[0093] After 66% of the oxime ether synthesis liquid was distilled off, the residue produced an endothermic signal at 58.0°C, and the sample absorbed heat in the range of 58.0-76.3°C was 49.6 J / g. When the temperature continued to rise to 147.9°C, an exothermic signal was produced, and the sample released heat in the range of 147.9-252.9°C was 179.5 J / g.

[0094] The residue in the system at the end point of distillation produces an endothermic signal at 64.1°C, and the sample absorbs 92.2 J / g of heat in the range of 64.1 to 81.4°C. As the temperature continues to rise, the sample produces an exothermic signal at 136.9°C, and the sample releases 531.2 J / g of heat in the range of 136.9 to 264.0°C.

[0095] b. According to the thermal stability screening results, the residue of the distillation endpoint system has the lowest initial exothermic decomposition temperature and the largest heat release. Therefore, the residue of the distillation endpoint system was selected to carry out thermal stability testing. The experimental results are shown in Table 7. The heat release data in the table are differential scanning calorimetry test results, and the rest are adiabatic calorimetry test results.

[0096] Table 7 Material stability information

[0097] Sample name The residue at the end of distillation Testing atmosphere Nitrogen Sample amount / g 2.6398 Phi 2.20 Initial outgassing temperature / ℃ 93.7 Initial exothermic decomposition temperature / ℃ 114.0 Heat release / (J / g) 531 Maximum temperature rise rate / (℃ / min) 1.3 Maximum pressure rise rate / (MPa / min) 0.07

[0098] The adiabatic calorimetry test results show that the sample begins to release gas at 93.7°C. When the temperature continues to rise to 114.0°C, the system begins to have obvious exothermic signals, the sample undergoes exothermic decomposition, and the system temperature and pressure rise slowly. Within the test range of 114.0-211.1°C, the heat release is 430 J / g (based on sample mass), the temperature rises by 97.1°C, the maximum temperature rise rate reaches 1.3°C / min at 169.0°C, and the maximum pressure rise rate reaches 0.07 MPa / min at 178.3.

[0099] c. Using the combined testing method of differential scanning calorimetry and adiabatic accelerating calorimetry, further decomposition kinetics research was carried out to obtain the decomposition thermodynamics and decomposition kinetics data of the residue in the distillation endpoint system.

[0100] The joint test results showed that the initial exothermic decomposition temperature of the residue in the distillation endpoint system was 114.0°C, and the decomposition heat was 531 J / g (based on sample mass). During the decomposition process, the maximum temperature rise rate was 1.3°C / min, and the maximum pressure rise rate was 0.07 MPa / min.

[0101] Through kinetic analysis, the relationship curve between the time and temperature of the maximum reaction rate in the thermal decomposition process of olefinic aldehyde waste liquid was obtained. Figure 4 As shown, under adiabatic conditions, the T of the residue in the distillation end point system is D24 It is 104.1℃.

[0102] 3) Thermal safety risk assessment of distillation process

[0103] T of the residue in the distillation end point system D24 The process involves a maximum distillation temperature of 85°C for the residue in the distillation end system. b ≤T D24 , which is an acceptable risk. Therefore, the possibility of thermal runaway risk in the distillation process of oxime ether synthesis liquid is not high, and there is enough time for artificial treatment of thermal runaway.

[0104] In another embodiment,

[0105] 1) Process description: An oil phase material is distilled to 150°C at atmospheric pressure for 6 hours. The fraction is the solvent and the distillation ratio is 60%.

[0106] 2) Testing process

[0107] a. According to the distillation process, four points were selected for thermal stability screening test, including the oil phase to be distilled, the residue after 33% of the oil phase was distilled out, the residue after 66% of the oil phase was distilled out, and the residue of the oil phase distillation endpoint system. The results are shown in Table 8. The data in the table are differential scanning calorimetry test results; "-" indicates that no relevant data were obtained within the test range.

[0108] Table 8 Thermal stability screening test results data table

[0109]

[0110] The differential scanning calorimetry test results showed that within the test range of 300°C, no obvious exothermic signals were detected in the oil phase to be distilled, the residue after 33% of the oil phase was distilled off, the residue after 66% of the oil phase was distilled off, and the residue in the distillation endpoint system. The sample did not decompose within the test range.

[0111] b. According to the thermal stability screening results, the residue from the oil phase distillation endpoint system has the longest heating time. Therefore, the residue from the distillation endpoint system is selected to carry out thermal stability test. The experimental results are shown in Table 9. The data in the table are the results of differential adiabatic calorimetry tests.

[0112] Table 9 Material stability information

[0113] Sample name The residue at the end of distillation Testing atmosphere Nitrogen Sample amount / g 3.1586 Phi 1.99

[0114] The adiabatic calorimetry test results show that within the 300°C test range, no obvious exothermic signal is generated by the sample. After the test system is cooled, the pressure returns to normal, indicating that the thermal stability of the sample is good during the test process.

[0115] c. Since the material did not decompose within the test range, the formula is: T D24 >T z -100, confirm T D24 range, then the residue T of the oil phase distillation end point system D24 >200℃.

[0116] 3) Thermal safety risk assessment of distillation process

[0117] T of the residue at the end point of oil phase distillation D24 >200℃, the process involves the highest distillation temperature of the residue at the end of the distillation system is 150℃, T b <T D24 , which is an acceptable risk. Therefore, the possibility of thermal runaway risk in the oil phase material distillation process is not high, and there is enough time for artificial treatment of thermal runaway.

[0118] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for thermal risk assessment of a fine chemical distillation process, characterized in that: The following steps are involved: S1. Obtain the upper temperature limit T of the distillation process to be evaluated p ; S2. Distill the materials to be distilled involved in the distillation process to be evaluated, select materials of different concentrations at each stage of distillation for thermal stability screening test, and conduct joint testing and research on materials with high dangerous concentrations to obtain their thermal stability. The joint testing and research methods include differential scanning calorimetry, pressure tracking differential scanning calorimetry, rapid screening calorimetry, adiabatic calorimetry, and microcalorimetry; S3. Perform decomposition kinetics analysis on dangerous high-concentration materials to obtain the temperature T corresponding to the maximum reaction rate reaching time of 24h under adiabatic conditions. D24 ; S4, T D24 and T p As an evaluation benchmark, the thermal safety risks of the distillation process are assessed.

2. A method for thermal risk assessment of a fine chemical distillation process according to claim 1, characterized in that: S2 includes selecting no less than 3 distillation materials with different concentration gradients for differential scanning calorimetry, pressure tracking differential scanning calorimetry or microcalorimetry to cover the entire distillation process.

3. A method for thermal risk assessment of a fine chemical distillation process according to claim 1, characterized in that: In the joint testing study in S2, thermal stability screening data was obtained by testing at the milligram to gram level based on material characteristics; For homogeneous materials, thermal stability screening data is obtained using milligram-level testing methods; For heterogeneous mixed materials, thermal stability screening data is obtained using gram-level testing methods.

4. A method for thermal risk assessment of a fine chemical distillation process according to claim 3, characterized in that: In S2, materials with high concentrations of dangerous substances are selected for rapid screening calorimetry and adiabatic calorimetry to obtain thermal stability data including the initial exothermic decomposition temperature and the amount of decomposition heat released.

5. The method for thermal risk assessment of a fine chemical distillation process according to claim 1, characterized in that: Obtaining the maximum reaction rate arrival time under adiabatic conditions in S3 includes: obtaining a relationship curve between the maximum reaction rate arrival time and the temperature during the thermal decomposition process of the material through decomposition kinetics analysis.

6. A method for thermal risk assessment of a fine chemical distillation process according to claim 1, characterized in that: S4 medium T D24 and T p The evaluation criteria include: When T p ≤T D24 When the thermal safety risk of the distillation process is considered acceptable; When T p >T D24 The thermal safety risk of the distillation process is considered unacceptable.

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