Benzene nitration reaction out-of-control identification method, identification system and out-of-control suppression method

Abstract

The present invention discloses a method for identifying a runaway benzene nitration reaction, comprising the following steps: establishing a trace benzene mixed acid system according to a target benzene nitration process; performing a programmed temperature test on the trace benzene mixed acid system to obtain the exothermic temperature range and heat release of the entire runaway benzene nitration reaction process, as well as information on reactants, intermediates, and products in each exothermic temperature range; performing simulation calculations using reaction molecular dynamics and quantum chemistry to obtain a set of runaway reaction paths and their thermodynamic data in each exothermic temperature range; determining the key initiating steps and runaway marker molecules for each exothermic temperature range; and monitoring the target benzene nitration process to identify the runaway benzene nitration reaction in the target benzene nitration process based on the monitoring data. The present invention also discloses a system for identifying a runaway benzene nitration reaction and a method for suppressing the runaway benzene nitration reaction. The present invention can quickly and accurately identify the early stages of the runaway benzene nitration process, so that suppressive measures can be taken in the early stages of the runaway benzene nitration process.

Description

Technical Field

[0001] The present invention relates to the technical field of diagnosis and control of safety out-of-control in chemical reaction processes, and in particular to a benzene nitration reaction out-of-control identification method, an identification system and an out-of-control suppression method. Background Art

[0002] Nitration reaction systems play a crucial role in chemical production. Nitrobenzene, a key chemical raw material and intermediate, is widely used in the production of pharmaceuticals, dyes, pesticides, explosives, and polyurethane foams. Currently, domestic nitrobenzene production primarily utilizes isothermal nitration reactors, while international production primarily utilizes adiabatic nitration reactors. Due to the high exothermicity and rapid reaction rate of the nitration reaction, localized heat accumulation can easily occur within the reactor. Furthermore, the nitration reaction materials, nitration products, and by-products pose a flammable and explosive hazard, making the process a frequent accident-prone process. Therefore, rapid early identification and control of runaway reactions in the benzene nitration reaction process are crucial for process safety control and accident prevention. However, current methods for identifying runaway processes in the benzene nitration reaction process remain unclear, and measures for preventing and controlling runaway reactions are immature.

[0003] Patent document CN209745932U discloses a system for testing the effectiveness of runaway reaction inhibitors. This system evaluates the effectiveness of runaway reaction inhibitors, enabling quantitative analysis of the inhibitory effects at different test levels for multiple influencing factors. Furthermore, it provides a large number of test results in a short period of time. This system comprehensively examines the inhibitory effects of runaway reaction inhibitors in practical engineering applications, thereby providing an optimal runaway reaction inhibition strategy. However, this solution does not provide methods for identifying and diagnosing runaway reactions.

[0004] Therefore, a method that can quickly identify runaway benzene nitration reactions is urgently needed.

[0005] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0006] One of the purposes of the present invention is to provide a method, an identification system and a method for suppressing a runaway benzene nitration reaction, thereby improving the problem of poor runaway identification in existing benzene nitration reactions.

[0007] Another object of the present invention is to provide a method, system and method for identifying a runaway benzene nitration reaction, thereby enabling early and rapid identification of the benzene nitration reaction.

[0008] Another object of the present invention is to provide a method, system and method for identifying a runaway benzene nitration reaction, so as to take measures to suppress the runaway benzene nitration reaction in its early stages.

[0009] To achieve the above-mentioned objectives, according to a first aspect of the present invention, a method for identifying a runaway benzene nitration reaction is provided, comprising the following steps: establishing a trace benzene mixed acid system according to a target benzene nitration process; performing a programmed temperature test on the trace benzene mixed acid system to obtain the exothermic temperature range and heat release of the entire runaway benzene nitration reaction process, as well as information on reactants, intermediates, and products in each exothermic temperature range; performing simulation calculations using reaction molecular dynamics and quantum chemistry based on the reactant, intermediate, and product information in each exothermic temperature range to obtain a set of runaway reaction paths and thermodynamic data thereof in each exothermic temperature range; determining the key initiating steps and runaway reaction marker molecules in each exothermic temperature range based on the set of runaway reaction paths and thermodynamic data thereof; and monitoring the temperature of the benzene nitration reaction process of the target benzene nitration process and the determined runaway marker molecules, and identifying the runaway benzene nitration reaction of the target benzene nitration process based on the monitoring data.

[0010] Furthermore, in the above technical solution, obtaining the set of reaction runaway paths in each exothermic temperature interval includes: constructing a closed-space three-dimensional molecular simulation system based on the reactant and product information in each exothermic temperature interval; obtaining the initial state of the three-dimensional molecular simulation system through energy minimization and kinetic equilibrium calculations; and using ReaxFF to perform molecular dynamics simulation to obtain the molecular evolution results of the reactants, intermediates and products in each exothermic temperature interval, tracking the evolution of molecular structure, and obtaining the set of reaction runaway paths in each exothermic temperature interval.

[0011] Furthermore, in the above technical solution, obtaining thermodynamic data of each exothermic temperature interval includes: using quantum chemical density functional theory to simulate and calculate the microscopic reaction activation energy barrier and reaction exotherm of each exothermic temperature interval.

[0012] Furthermore, in the above technical solution, the exothermic reaction step with the smallest microscopic reaction activation energy barrier in the exothermic temperature range is used as the key initiating step for the runaway reaction in the exothermic temperature range.

[0013] Furthermore, in the above technical solution, the out-of-control marker molecule is determined based on the intermediate of the key initiating step of the out-of-control reaction.

[0014] Furthermore, in the above technical solution, establishing the trace benzene mixed acid system is to configure the trace benzene mixed acid system according to the benzene mixed acid system of the target benzene nitration process.

[0015] Furthermore, in the above technical solution, a reaction calorimetry method is used to perform a programmed temperature test on the trace mixed acid system.

[0016] Furthermore, in the above technical solution, the temperature range of the programmed temperature test is 25°C to 500°C.

[0017] Furthermore, in the above technical solution, the temperature increase interval of the programmed temperature test is 0.1°C to 2°C.

[0018] Furthermore, in the above technical solution, the identification of the out-of-control benzene nitration reaction of the target benzene nitration process based on the monitoring data includes: when the detected concentration of the benzenesulfonic acid functional group in the system begins to be greater than the first concentration limit value, the identification result is that the benzene nitration reaction is in the out-of-control transition period; when the detected concentration of the phenol functional group is greater than the second concentration limit value or the detected concentration of NO is greater than the third concentration limit value, the identification result is that the benzene nitration reaction is in the early stage of the first out-of-control; and when the detected concentration of NO2 is greater than the fifth limit value, the identification result is that the benzene nitration reaction is in the early stage of the second out-of-control.

[0019] Furthermore, in the above technical solution, the identification of the out-of-control benzene nitration reaction of the target benzene nitration process based on the monitoring data includes: when the detected concentration of the benzenesulfonic acid functional group in the system begins to be greater than the first concentration limit value, or the temperature is in the first limit interval and the average temperature rise rate within 10 minutes is greater than the first temperature rise limit value, the identification result is that the benzene nitration reaction is in the out-of-control transition period; when the detected concentration of the phenol functional group is greater than the second concentration limit value, the detected concentration of NO is greater than the third concentration limit value, the detected concentration of SO2 is greater than the fourth concentration limit value, or the temperature is in the second limit interval and the average temperature rise rate within 10 minutes is greater than the second temperature rise limit value, the identification result is that the benzene nitration reaction is in the early stage of the first out-of-control; and when the detected concentration of NO2 is greater than the fifth limit value, or the temperature is higher than the temperature limit value and the average temperature rise rate within 10 minutes is greater than the third temperature rise limit value, the identification result is that the benzene nitration reaction is in the early stage of the second out-of-control.

[0020] According to the second aspect of the present invention, the present invention provides a method for suppressing a runaway benzene nitration reaction, which comprises the following steps: identifying a runaway benzene nitration reaction using a runaway benzene nitration reaction identification method such as any one of the above-mentioned technical solutions; when the identification result is a runaway transition period, adjusting the process parameters to return to a normal range; when the identification result is an early stage of a primary runaway, taking cooling measures on the target benzene nitration process to suppress the runaway; and when the identification result is an early stage of a secondary runaway, initiating an emergency disposal response to the target benzene nitration process.

[0021] According to a third aspect of the present invention, the present invention provides a benzene nitration reaction out-of-control identification system, which includes: a reaction calorimeter, which is used to obtain all exothermic temperature intervals and heat release of the benzene mixed acid system of the target benzene nitration process; a sample analyzer, which is used to obtain reactant, intermediate and product information of each exothermic temperature interval; a simulation analysis unit, which is used to obtain the reactant, intermediate and product information of each exothermic temperature interval, and utilize reaction molecular dynamics and quantum chemical simulation calculations to obtain a set of reaction out-of-control paths and their thermodynamic data for each exothermic temperature interval, so as to determine the key initiating steps and out-of-control marker molecules of the reaction out-of-control in each exothermic temperature interval; and an out-of-control identification unit, which is used to monitor the temperature of the benzene nitration reaction process of the target benzene nitration process and the determined out-of-control marker molecules, and identify the out-of-control of the benzene nitration reaction of the target benzene nitration process based on the monitoring data.

[0022] Furthermore, in the above technical solution, the sample analyzer is a chromatograph / mass spectrometer and / or a Fourier transform infrared spectrometer.

[0023] Furthermore, in the above technical solution, the out-of-control identification unit includes a temperature sensor and an infrared spectrum analyzer.

[0024] Compared with the prior art, the present invention has one or more of the following beneficial effects:

[0025] 1. By combining thermal safety calorimetric analysis technology, reaction component analysis, reaction molecular dynamics and quantum chemical simulation, the key triggering steps and runaway marker molecules in each exothermic temperature range are determined, thereby enabling rapid and accurate identification of the early stages of runaway in the target benzene nitration process.

[0026] 2. Based on the rapid identification of early runaway, the present invention can provide reliable real-time diagnosis for the safety of the benzene nitration reaction, making it possible to adopt runaway suppression measures in a timely manner and avoid thermal runaway accidents in the target benzene nitration process.

[0027] 3. The present invention can identify out-of-control reaction by monitoring the temperature of the benzene nitration reaction process and the determined out-of-control marker molecules. The method is simple and rapid, and the identification result has high accuracy.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other purposes, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 1 is a flow chart of a method for identifying a runaway benzene nitration reaction according to one embodiment of the present invention.

[0030] Figure 2 1 is a block diagram of a system for identifying an out-of-control benzene nitration reaction according to one embodiment of the present invention. DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0032] Unless expressly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising” will be understood to include the stated elements or components but not to exclude other elements or components.

[0033] In this document, for ease of description, spatially relative terms such as "below," "beneath," "down," "above," "above," etc. may be used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that the spatially relative terms are intended to encompass different orientations of an object in use or operation in addition to the orientation depicted in the drawings. For example, if the object in the drawings is turned over, the element described as being "below" or "below" other elements or features will be oriented "above" the element or feature. Therefore, the exemplary term "below" can include both below and above directions. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatially relative terms used herein should be interpreted accordingly.

[0034] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit specific positions or relative relationships. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable with each other.

[0035] like Figure 1 As shown, the method for identifying an out-of-control benzene nitration reaction according to a specific embodiment of the present invention comprises the following steps:

[0036] S110 establishes a trace benzene mixed acid system based on the target benzene nitration process.

[0037] According to the composition of the benzene and mixed acid reaction system of the target benzene nitration process, a trace benzene mixed acid system was established.

[0038] S120 performs a programmed temperature test on a trace benzene mixed acid system to obtain the exothermic temperature range and heat release during the entire runaway benzene nitration reaction, as well as information on reactants, intermediates, and products in each exothermic temperature range.

[0039] Furthermore, in one or more exemplary embodiments of the present invention, a reaction calorimetry method is used to perform a temperature programming test on a trace mixed acid system.

[0040] Furthermore, in one or more exemplary embodiments of the present invention, step S120 includes a two-stage temperature programming test:

[0041] S121 performs mg-level temperature-programmed calorimetry on a trace amount of benzene mixed acid system, determining the complete exothermic temperature range and heat release during the runaway benzene nitration reaction. This mg-level temperature-programmed calorimetry can approximately eliminate the effects of interfacial transfer, allowing for more accurate determination of the complete exothermic temperature range.

[0042] S122 performs a g-level programmed temperature calorimetry test on a trace amount of benzene mixed acid system, collects gas and liquid phase samples in each exothermic temperature interval, analyzes the samples, and obtains information on reactants, intermediates, and products in each exothermic temperature interval. The g-level programmed temperature calorimetry test can collect an appropriate amount of gas and liquid phase samples to analyze the reactants, intermediates, and products in each exothermic temperature interval. It should be understood that the reactants, intermediates, and products in each exothermic temperature interval refer to the gas and liquid phase components at the lowest temperature, the gas and liquid phase components at the intermediate sampling interval temperature, and the gas and liquid phase components at the highest temperature within a certain exothermic temperature interval.

[0043] Furthermore, in one or more exemplary embodiments of the present invention, the sampling temperature interval for collecting gas and liquid phase samples in each exothermic temperature range is 10°C to 50°C. If the sampling interval is less than 10°C, it is difficult to achieve control operation, and if the sampling interval exceeds 50°C, the intermediate information may not be obtained.

[0044] Furthermore, in one or more exemplary embodiments of the present invention, the temperature range of the temperature programming test is 25° C. to 500° C. Furthermore, in one or more exemplary embodiments of the present invention, the temperature increase interval of the temperature programming test is 0.1° C. to 2° C.

[0045] S130 uses reaction molecular dynamics and quantum chemistry to perform simulation calculations based on the reactant, intermediate, and product information in each exothermic temperature interval to obtain a set of reaction runaway paths and their thermodynamic data in each exothermic temperature interval.

[0046] Furthermore, in one or more exemplary embodiments of the present invention, obtaining a set of runaway reaction paths for each exothermic temperature interval includes: constructing a closed-space three-dimensional molecular simulation system based on the reactant and product information of each exothermic temperature interval; obtaining the initial state of the three-dimensional molecular simulation system through energy minimization and kinetic equilibrium calculations; and performing molecular dynamics simulation using ReaxFF to obtain the molecular evolution results of the reactants, intermediates, and products in each exothermic temperature interval, tracking the evolution of the molecular structure, and obtaining a set of runaway reaction paths for each exothermic temperature interval.

[0047] Furthermore, in one or more exemplary embodiments of the present invention, obtaining thermodynamic data for each exothermic temperature interval includes: performing simulations using quantum chemical density functional theory to calculate the microscopic reaction activation energy barrier and reaction exotherm for each exothermic temperature interval.

[0048] S140 determines the key triggering steps and runaway marker molecules for the runaway reaction in each exothermic temperature interval based on the runaway reaction path set and thermodynamic data of the runaway reaction in each exothermic temperature interval.

[0049] Furthermore, in one or more exemplary embodiments of the present invention, the microscopic reaction activation energy barriers of each exothermic temperature interval are screened, and the exothermic reaction step with the smallest microscopic reaction activation energy barrier in the exothermic temperature interval is taken as the key initiating step for the reaction runaway in the exothermic temperature interval.

[0050] Furthermore, in one or more exemplary embodiments of the present invention, the runaway marker molecule is determined based on an intermediate of a key initiating step of a runaway reaction.

[0051] S150 monitors the temperature of the benzene nitration reaction process of the target benzene nitration process and the determined out-of-control marker molecules, and identifies the out-of-control benzene nitration reaction of the target benzene nitration process based on the monitoring data.

[0052] Further, in one or more exemplary embodiments of the present invention, identifying, based on monitoring data, that the benzene nitration reaction of the target benzene nitration process is out of control includes:

[0053] When the detected concentration of the benzenesulfonic acid functional group in the system begins to exceed the first concentration limit, the identification result is that the benzene nitration reaction is in the out-of-control transition period;

[0054] When the detected concentration of the phenol functional group is greater than the second concentration limit value or the detected concentration of NO is greater than the third concentration limit value, the identification result is that the benzene nitration reaction is in the early stage of a runaway reaction; and

[0055] When the detected NO2 concentration is greater than the fifth limit value, the identification result is that the benzene nitration reaction is in the early stage of secondary runaway.

[0056] Furthermore, in one or more exemplary embodiments of the present invention, the out-of-control marker monitoring results and the temperature monitoring results may be combined to identify out-of-control benzene nitration reaction. Identifying out-of-control benzene nitration reaction in the target benzene nitration process based on the monitoring data includes:

[0057] When the detected concentration of the benzenesulfonic acid functional group in the system begins to exceed the first concentration limit, or the temperature is in the first limit range and the average temperature rise rate within 10 minutes is greater than the first temperature rise limit, the identification result is that the benzene nitration reaction is in the runaway transition period;

[0058] When the detected concentration of phenol functional groups is greater than the second concentration limit, the detected concentration of NO is greater than the third concentration limit, the detected concentration of SO2 is greater than the fourth concentration limit, or the temperature is within the second limit range and the average temperature rise rate within 10 minutes is greater than the second temperature rise limit, the identification result is that the benzene nitration reaction is in the early stage of a runaway reaction; and

[0059] When the detected NO2 concentration is greater than the fifth limit value, or the temperature is higher than the temperature limit value and the average temperature rise rate within 10 minutes is greater than the third temperature rise limit value, the identification result is that the benzene nitration reaction is in the early stage of secondary runaway.

[0060] According to a specific embodiment of the present invention, a method for suppressing a runaway benzene nitration reaction comprises the following steps: identifying a runaway benzene nitration reaction using a runaway benzene nitration reaction identification method such as any one of the above-mentioned technical solutions; promptly adjusting process parameters to return to a normal range when the identification result is an out-of-control transition period; taking cooling measures on the target benzene nitration process to suppress the runaway benzene nitration reaction when the identification result is an early stage of a primary runaway; and initiating an emergency disposal response to the target benzene nitration process when the identification result is an early stage of a secondary runaway.

[0061] Combine Figure 2 As shown, a benzene nitration reaction out-of-control identification system according to a specific embodiment of the present invention includes: a reaction calorimeter 10, which is used to obtain all exothermic temperature intervals and heat release of the benzene mixed acid system of the target benzene nitration process; a sample analyzer 20, which is used to obtain reactant, intermediate and product information of each exothermic temperature interval; a simulation analysis unit 30, which is used to obtain the reactant and product information of each exothermic temperature interval, and use reaction molecular dynamics and quantum chemical simulation calculations to obtain a reaction out-of-control path set and its thermodynamic data for each exothermic temperature interval, so as to determine the key triggering steps and out-of-control marker molecules of the reaction out-of-control in each exothermic temperature interval; and an out-of-control identification unit 40, which is used to monitor the temperature of the benzene nitration reaction process of the target benzene nitration process and the determined out-of-control marker molecules, and identify the out-of-control of the benzene nitration reaction of the target benzene nitration process based on the monitoring data.

[0062] Furthermore, in one or more exemplary embodiments of the present invention, the sample analyzer 20 is a chromatograph / mass spectrometer and / or a Fourier transform infrared spectrometer.

[0063] Furthermore, in one or more exemplary embodiments of the present invention, the out-of-control identification unit 40 includes a temperature sensor and an infrared spectrum analyzer.

[0064] The following describes in more detail the method, system, and method for suppressing a runaway benzene nitration reaction by using specific embodiments. It should be understood that the present invention is not limited thereto.

[0065] Example 1

[0066] Based on the benzene and mixed acid reaction system composition of the target benzene nitration process, a mixed acid was prepared with a molar ratio of sulfuric acid to nitric acid of 2:1. Benzene and the mixed acid were then added dropwise to the sample cell of the reaction calorimeter at a molar ratio of benzene to nitric acid of 1:1.

[0067] A programmed temperature calorimetry test was performed on the benzene-mixed acid system, with the temperature rising from room temperature (25°C) to a high temperature (500°C) at a heating rate of 1°C / min. The temperature and heat flow test results were recorded in real time using control software. All exothermic temperature intervals and heat release during the entire runaway benzene nitration reaction were obtained based on the temperature-heat flow curve. In this embodiment, four exothermic temperature intervals were obtained by the programmed temperature calorimetry test. The first exothermic temperature interval was 25°C to 150°C, with a heat release of 328.9 J / g; the second exothermic temperature interval was 150°C to 190°C, with a heat release of 40 J / g; the third exothermic temperature interval was 190°C to 250°C, with a heat release of 325.4 J / g; and the fourth exothermic temperature interval was 270°C to 355°C, with a heat release of 112.9 J / g. Among them, the first exothermic interval is the main reaction interval of benzene nitration; the second exothermic interval is the out-of-control transition period; the third exothermic interval has a maximum heat release rate of 100mW, which is the first out-of-control interval of the benzene nitration process; the fourth exothermic interval has a maximum heat release rate of 50mW, which is the second out-of-control interval of the benzene nitration process.

[0068] Gas and liquid samples were collected at different stages of the programmed temperature calorimetry test and analyzed using GC / MS for composition and structure. The products in the main reaction zone were over 95% nitrobenzene; over 50% of the products in the runaway transition period were nitrobenzenesulfonic acid. The products in the primary runaway zone exhibited coking, with the primary functional groups being phenol, mercaptan, and nitro groups, and the gaseous products being NO and SO2. The products in the secondary runaway zone exhibited severe coking, with the primary functional groups being phenol and hydroxyl groups, and the gaseous products being NO2, NO, and N2.

[0069] Reaction molecular dynamics simulations were used to obtain a set of runaway reaction pathways for each exothermic temperature range. Specifically, a closed-space three-dimensional molecular simulation system was first constructed based on the reactant and product components. The simulation system's composition and number of molecules could be set and adjusted based on actual conditions. The molecular simulation system was then subjected to energy minimization and kinetic equilibrium calculations to achieve equilibrium, obtaining the initial state of the simulation. ReaxFF reaction molecular dynamics simulations were then used to simulate the reaction process in the three-dimensional molecular simulation system. The simulation output data was analyzed to obtain the evolution of the chemical molecules and the generated characteristic product molecules, tracking the evolution of the molecular structure to obtain a set of runaway reaction pathways for each exothermic temperature range: ① Sulfonation of nitrobenzene and sulfuric acid to form nitrobenzenesulfonic acid; ② The nitro group of nitrobenzenesulfonic acid abstracts the sulfonic acid hydrogen to form an ONOH functional group intermediate; ③ The CN bond of the nitrobenzenesulfonic acid-ONOH intermediate breaks to form ONOH, which then decomposes to form ON and OH; ④ The sulfonic acid radical of the nitrobenzenesulfonic acid intermediate decomposes to form a hydroquinone radical and SO2; ⑤ NO2, generated by the decomposition of nitrobenzene, reacts with the benzene radical to form a phenol radical and NO, which then decomposes to form an OH radical by hydrogen abstraction.

[0070] Quantum chemical density functional theory (DFT) was used to calculate the activation energy barriers and reaction exothermic characteristics of the microscopic reactions of chemical functional groups. The enthalpies and Gibbs free energies of reactants, products, intermediates, and transition states were determined, along with the microscopic activation energy barriers and reaction exotherms. Based on molecular dynamics and quantum chemical simulations, combined with product composition analysis, the marker molecule for the runaway transition phase of the benzene nitration reaction system was identified as nitrobenzenesulfonic acid. The early marker molecules for primary runaway were phenol functional groups, NO, and SO₂, and the early marker molecule for secondary runaway was NO₂.

[0071] By monitoring the marker molecules and early temperature range of the benzene nitration reaction process, the out-of-control benzene nitration reaction can be quickly identified and suppressed at an early stage:

[0072] When the detected concentration of benzenesulfonic acid functional groups in the system is greater than 5%, or the temperature is between 150°C and 190°C (inclusive) and the average temperature rise rate within 10 minutes is greater than 0.15°C / min, the benzene nitration reaction is identified as being in the runaway transition period. Once the reaction system is identified as in the runaway transition period, the process parameters should be adjusted promptly to return to the normal range.

[0073] When the detection concentration of phenol functional groups is greater than 5%, the detection concentration of NO is greater than 10ppm, and the detection concentration of SO2 is greater than 0.01mg / m 3, or when the temperature is between 190°C and 250°C (excluding 190°C and including 250°C) and the average temperature rise rate within 10 minutes is greater than 0.5°C / min, the identification result is that the benzene nitration reaction is in the early stage of a runaway reaction; when the identification result is in the early stage of a runaway reaction, cooling measures are taken for the target benzene nitration process to suppress the runaway reaction; and

[0074] If the detected NO2 concentration is greater than 10 ppm, or the temperature is greater than 250°C with an average temperature rise rate greater than 0.2°C / min over 10 minutes, the benzene nitration reaction is identified as being in the early stages of a secondary runaway. When this is the case, an emergency response is initiated for the target benzene nitration process.

[0075] Example 2

[0076] Based on the benzene and mixed acid reaction system composition of the target benzene nitration process, a mixed acid was first prepared with a molar ratio of sulfuric acid to nitric acid of 5:1. Benzene and the mixed acid were then added dropwise to the sample cell of the reaction calorimeter at a molar ratio of 1:1.

[0077] A programmed temperature calorimetry test was performed on the benzene-mixed acid system, with the temperature rising from room temperature (25°C) to a high temperature (500°C) at a heating rate of 1°C / min. The temperature and heat flow test results were recorded in real time using control software. All exothermic temperature intervals and heat release during the entire runaway benzene nitration reaction were obtained based on the temperature-heat flow curve. In this embodiment, four exothermic temperature intervals were obtained by the programmed temperature calorimetry test. The first exothermic temperature interval was 25°C to 125°C, with a heat release of 297.7 J / g; the second exothermic temperature interval was 130°C to 180°C, with a heat release of 35 J / g; the third exothermic temperature interval was 180°C to 255°C, with a heat release of 332.1 J / g; and the fourth exothermic temperature interval was 270°C to 355°C, with a heat release of 100.3 J / g. Among them, the first exothermic interval is the main reaction interval of benzene nitration; the second exothermic interval is the out-of-control transition period; the third exothermic interval has a maximum heat release rate of 120mW, which is the first out-of-control interval of the benzene nitration process; the fourth exothermic interval has a maximum heat release rate of 55mW, which is the second out-of-control interval of the benzene nitration process.

[0078] Gas and liquid samples were collected at different stages of the programmed temperature calorimetry test and analyzed using GC / MS for composition and structure. Over 90% of the products in the main reaction zone were nitrobenzene; over 40% of the products in the runaway transition period were nitrobenzene disulfonic acid. The products in the primary runaway zone exhibited coking, with the primary functional groups being phenol, mercaptan, and nitro groups, and the gaseous products being NO and SO2. The products in the secondary runaway zone exhibited severe coking, with the primary functional groups being phenol and hydroxyl groups, and the gaseous products being NO2, NO, and N2.

[0079] Reaction molecular dynamics simulations were used to obtain a set of runaway reaction pathways for each exothermic temperature range. Specifically, a closed-space three-dimensional molecular simulation system was first constructed based on the reactant and product components. The simulation system's composition and number of molecules could be set and adjusted based on actual conditions. The molecular simulation system was then subjected to energy minimization and kinetic equilibrium calculations to achieve equilibrium, obtaining the initial state of the simulation. ReaxFF reaction molecular dynamics simulations were then used to simulate the reaction process within the three-dimensional molecular simulation system. The simulation output data was analyzed to obtain the evolution of the chemical molecules and the characteristic product molecules generated. The molecular structure evolution was tracked to obtain a set of runaway reaction pathways for each exothermic temperature range: ① Sulfonation of nitrobenzene and sulfuric acid to form nitrobenzene disulfonic acid; ② The nitro group of nitrobenzene disulfonic acid abstracted the sulfonic hydrogen to form an ONOH functional group intermediate; ③ The CN bond of the nitrobenzene disulfonic acid ONOH intermediate cleaved to form ONOH, which then decomposed to form ON and OH; ④ The sulfonic acid radical of the nitrobenzene disulfonic acid intermediate decomposed to form pyrogallol radicals and SO2; ⑤ NO2, generated by the decomposition of nitrobenzene, reacted with the benzene radical to form phenol radicals and NO, which then decomposed to form OH radicals by hydrogen abstraction.

[0080] Quantum chemical density functional theory (DFT) was used to calculate the activation energy barriers and reaction exothermic characteristics of the microscopic reactions of chemical functional groups. The enthalpies and Gibbs free energies of reactants, products, intermediates, and transition states were determined, along with the microscopic activation energy barriers and reaction exotherms. Based on molecular dynamics and quantum chemical simulations, combined with product composition analysis, the marker molecule for the runaway transition phase of the benzene nitration reaction system was identified as nitrobenzene disulfonic acid. The primary runaway marker molecules were phenol functional groups, NO, and SO₂, and the secondary runaway marker molecule was NO₂.

[0081] By monitoring the marker molecules and early temperature range of the benzene nitration reaction process, the out-of-control benzene nitration reaction can be quickly identified and suppressed at an early stage:

[0082] When the concentration of benzenesulfonic acid functional groups detected in the system begins to exceed 10%, or the temperature is between 125°C and 180°C (inclusive) and the average temperature rise rate within 10 minutes is greater than 0.3°C / min, the benzene nitration reaction is identified as being in the runaway transition period. Once the reaction system is identified as in the runaway transition period, the process parameters should be adjusted promptly to return to the normal range.

[0083] When the detection concentration of phenol functional groups is greater than 7.5%, the detection concentration of NO is greater than 15ppm, and the detection concentration of SO2 is greater than 0.02mg / m 3, or when the temperature is between 180°C and 255°C (excluding 180°C and including 255°C) and the average temperature rise rate within 10 minutes is greater than 0.8°C / min, the identification result is that the benzene nitration reaction is in the early stage of a runaway reaction; when the identification result is in the early stage of a runaway reaction, cooling measures are taken for the target benzene nitration process to suppress the runaway reaction; and

[0084] If the detected NO2 concentration is greater than 5 ppm, or the temperature is greater than 255°C with an average temperature rise rate greater than 0.15°C / min over 10 minutes, the benzene nitration reaction is identified as being in the early stages of a secondary runaway. If this is the case, an emergency response is initiated for the target benzene nitration process.

[0085] Example 3

[0086] Based on the benzene and mixed acid reaction system composition of the target benzene nitration process, a mixed acid was prepared with a molar ratio of sulfuric acid to nitric acid of 2:1. Benzene and the mixed acid were then added dropwise to the sample cell of the reaction calorimeter at a molar ratio of 1:2.

[0087] A programmed temperature calorimetry test was performed on the benzene-mixed acid system, with the temperature rising from room temperature (25°C) to a high temperature (500°C) at a heating rate of 1°C / min. The temperature and heat flow test results were recorded in real time using control software. All exothermic temperature intervals and heat release during the entire runaway benzene nitration reaction were obtained based on the temperature-heat flow curve. In this embodiment, four exothermic temperature intervals were obtained by the programmed temperature calorimetry test. The first exothermic temperature interval was 25°C to 150°C, with a heat release of 405.3 J / g; the second exothermic temperature interval was 150°C to 190°C, with a heat release of 35 J / g; the third exothermic temperature interval was 190°C to 260°C, with a heat release of 287.5 J / g; and the fourth exothermic temperature interval was 260°C to 355°C, with a heat release of 155.2 J / g. Among them, the first exothermic interval is the main reaction interval of benzene nitration; the second exothermic interval is the out-of-control transition period; the third exothermic interval has a maximum heat release rate of 110mW, which is the first out-of-control interval of the benzene nitration process; the fourth exothermic interval has a maximum heat release rate of 60mW, which is the second out-of-control interval of the benzene nitration process.

[0088] Gas and liquid samples were collected at different stages of the programmed temperature calorimetry test and analyzed using GC / MS for composition and structure. Over 85% of the products in the main reaction zone were dinitrobenzene; over 45% of the products in the runaway transition period were dinitrobenzene sulfonic acid. The products in the primary runaway zone exhibited coking, with the primary functional groups being phenol, mercaptan, and nitro groups, and the gaseous products being NO and SO2. The products in the secondary runaway zone exhibited severe coking, with the primary functional groups being phenol and hydroxyl groups, and the gaseous products being NO2, NO, and N2.

[0089] Reaction molecular dynamics simulation is used to obtain the set of reaction runaway paths in each exothermic temperature range. Specifically, a closed-space three-dimensional molecular simulation system is first constructed based on the reactant and product components. The composition and number of molecules in the simulation system can be set and adjusted according to the actual situation. The molecular simulation system is subjected to energy minimization and kinetic equilibrium calculations to achieve equilibrium in the molecular system and obtain the initial state of the simulation. Then, the three-dimensional molecular simulation system is simulated and calculated using ReaxFF reaction molecular dynamics. The output data of the simulation calculation is analyzed to obtain the evolution results of the chemical molecules and the generated characteristic product molecules, and the molecular structure evolution is tracked to obtain the set of reaction runaway paths in each exothermic temperature range: ① Sulfonation of dinitrobenzene and sulfuric acid to form dinitrobenzene sulfonic acid; ② The nitro group of dinitrobenzene sulfonic acid abstracts the sulfonic hydrogen to form an ONOH functional group intermediate; ③ The CN bond of the dinitrobenzene sulfonic acid ONOH intermediate breaks to form ONOH, which then decomposes to form ON and OH; ④ The sulfonic acid radical of the dinitrobenzene sulfonic acid intermediate decomposes to form benzenetriol radicals and SO2; ⑤ The NO2 generated by the decomposition of dinitrobenzene reacts with the benzene radical to form benzenetriol radicals and NO, and the NO hydrogen abstraction decomposes to form OH radicals.

[0090] Quantum chemical density functional theory (DFT) was used to calculate the activation energy barriers and reaction exothermic characteristics of the microscopic reactions of chemical functional groups. The enthalpies and Gibbs free energies of reactants, products, intermediates, and transition states were determined, along with the microscopic activation energy barriers and reaction exotherms. Based on molecular dynamics and quantum chemical simulations, combined with product composition analysis, the marker molecule for the runaway transition phase of the benzene nitration reaction system was identified as dinitrobenzenesulfonic acid. The primary runaway marker molecules were phenol functional groups, NO, and SO₂, and the secondary runaway marker molecule was NO₂.

[0091] By monitoring the marker molecules and early temperature range of the benzene nitration reaction process, the out-of-control benzene nitration reaction can be quickly identified and suppressed at an early stage:

[0092] When the detected concentration of benzenesulfonic acid functional groups in the system begins to exceed 5%, or the temperature is between 150°C and 190°C (inclusive) and the average temperature rise rate within 10 minutes is greater than 0.15°C / min, the benzene nitration reaction is identified as being in the runaway transition period, with the detected concentration of benzenesulfonic acid functional groups as the priority criterion. Once the reaction system is identified as in the transition period, the process parameters should be adjusted promptly to return to the normal range.

[0093] When the detection concentration of phenol functional groups is greater than 7.5%, the detection concentration of NO is greater than 15ppm, and the detection concentration of SO2 is greater than 0.01mg / m 3When the temperature is between 190°C and 260°C (excluding 190°C and including 260°C) and the average temperature rise rate within 10 minutes is greater than 0.6°C / min, the identification result is that the benzene nitration reaction is in the early stage of a runaway reaction; when the identification result is in the early stage of a runaway reaction, cooling measures are taken for the target benzene nitration process to suppress the runaway reaction; and

[0094] If the detected NO2 concentration is greater than 10 ppm, or the temperature is greater than 260°C with an average temperature rise rate greater than 0.3°C / min over 10 minutes, the benzene nitration reaction is identified as being in the early stages of a secondary runaway. If this is the case, an emergency response is initiated for the target benzene nitration process.

[0095] Example 4

[0096] Based on the benzene and mixed acid reaction system composition of the target benzene nitration process, a mixed acid was prepared with a molar ratio of sulfuric acid to nitric acid of 5:1. Benzene and the mixed acid were then added dropwise to the sample cell of the reaction calorimeter at a molar ratio of benzene to nitric acid of 1:2.

[0097] A programmed temperature calorimetry test was performed on the benzene-mixed acid system, with the temperature rising from room temperature (25°C) to a high temperature (500°C) at a heating rate of 1°C / min. The temperature and heat flow test results were recorded in real time using control software. All exothermic temperature intervals and heat release during the entire runaway benzene nitration reaction were obtained based on the temperature-heat flow curve. In this embodiment, four exothermic temperature intervals were obtained by the programmed temperature calorimetry test. The first exothermic temperature interval was 25°C to 130°C, with a heat release of 326.8 J / g; the second exothermic temperature interval was 130°C to 175°C, with a heat release of 30 J / g; the third exothermic temperature interval was 175°C to 250°C, with a heat release of 287.5 J / g; and the fourth exothermic temperature interval was 270°C to 350°C, with a heat release of 157.5 J / g. Among them, the first exothermic interval is the main reaction interval of benzene nitration; the second exothermic interval is the out-of-control transition period; the third exothermic interval has a maximum heat release rate of 130mW, which is the first out-of-control interval of the benzene nitration process; the fourth exothermic interval has a maximum heat release rate of 70mW, which is the second out-of-control interval of the benzene nitration process.

[0098] Gas and liquid samples were collected at different stages of the programmed temperature calorimetry test and analyzed using GC / MS for composition and structure. Over 90% of the products in the main reaction zone were dinitrobenzene; over 40% of the products in the runaway transition period were dinitrobenzene disulfonic acid. The products in the primary runaway zone exhibited coking, with the primary functional groups being phenol, mercaptan, and nitro groups, and the gaseous products being NO and SO2. The products in the secondary runaway zone exhibited severe coking, with the primary functional groups being phenol and hydroxyl groups, and the gaseous products being NO2, NO, and N2.

[0099] Reaction molecular dynamics simulation is used to obtain the set of reaction runaway paths in each exothermic temperature range. Specifically, a closed-space three-dimensional molecular simulation system is first constructed based on the reactant and product components. The composition and number of molecules in the simulation system can be set and adjusted according to the actual situation. The molecular simulation system is subjected to energy minimization and kinetic equilibrium calculations to achieve equilibrium in the molecular system and obtain the initial state of the simulation. Then, the three-dimensional molecular simulation system is simulated and calculated using ReaxFF reaction molecular dynamics. The output data of the simulation calculation are analyzed to obtain the evolution results of the chemical molecules and the generated characteristic product molecules, and the molecular structure evolution is tracked to obtain the set of reaction runaway paths in each exothermic temperature range: ① Sulfonation of dinitrobenzene and sulfuric acid to form dinitrobenzene disulfonic acid; ② The nitro group of dinitrobenzene disulfonic acid abstracts the sulfonic hydrogen to form an ONOH functional group intermediate; ③ The CN bond of the dinitrobenzene disulfonic acid ONOH intermediate breaks to form ONOH, which then decomposes to form ON and OH; ④ The sulfonic acid radical of the dinitrobenzene disulfonic acid intermediate decomposes to form benzene tetraphenol radicals and SO2; ⑤ The NO2 generated by the decomposition of dinitrobenzene reacts with the benzene radical to form benzene diphenol radicals and NO, and the NO hydrogen abstraction decomposes to form OH radicals.

[0100] Quantum chemical density functional theory (DFT) was used to calculate the activation energy barriers and reaction exothermic characteristics of the microscopic reactions of chemical functional groups. The enthalpies and Gibbs free energies of reactants, products, intermediates, and transition states were determined, along with the microscopic activation energy barriers and reaction exotherms. Based on molecular dynamics and quantum chemical simulations, combined with product composition analysis, the marker molecule for the runaway transition phase of the benzene nitration reaction system was identified as dinitrobenzene disulfonic acid. The primary runaway marker molecules were phenol functional groups, NO, and SO₂, and the secondary runaway marker molecule was NO₂.

[0101] By monitoring the marker molecules and early temperature range of the benzene nitration reaction process, the out-of-control benzene nitration reaction can be quickly identified and suppressed at an early stage:

[0102] When the concentration of benzenesulfonic acid functional groups detected in the system begins to exceed 10%, or the temperature is between 130°C and 175°C (inclusive) and the average temperature rise rate within 10 minutes is greater than 0.3°C / min, the benzene nitration reaction is identified as being in the out-of-control transition period. Once the reaction system is identified as in the transition period, the process parameters should be adjusted promptly to return to the normal range.

[0103] When the detection concentration of phenol functional groups is greater than 10%, the detection concentration of NO is greater than 15ppm, and the detection concentration of SO2 is greater than 0.02mg / m 3, or when the temperature is between 175℃ and 250℃ and the average temperature rise rate within 10 minutes is greater than 0.8℃ / min, the identification result is that the benzene nitration reaction is in the early stage of a runaway. When the identification result is in the early stage of a runaway, cooling measures are taken for the target benzene nitration process to suppress the runaway.

[0104] If the detected NO2 concentration is greater than 10 ppm, or the temperature is above 250°C with an average temperature rise rate greater than 0.4°C / min over 10 minutes, the benzene nitration reaction is identified as being in the early stages of a secondary runaway. If this is the case, an emergency response is initiated for the target benzene nitration process.

[0105] Example 5

[0106] Based on the benzene and mixed acid reaction system composition of the target benzene nitration process, a mixed acid was prepared with a molar ratio of sulfuric acid to nitric acid of 5:1. Benzene and the mixed acid were then added dropwise to the sample cell of the reaction calorimeter at a molar ratio of benzene to nitric acid of 1:3.

[0107] A programmed temperature calorimetry test was performed on the benzene-mixed acid system, with the temperature rising from room temperature (25°C) to a high temperature (500°C) at a heating rate of 1°C / min. The temperature and heat flow test results were recorded in real time using control software. All exothermic temperature intervals and heat release during the entire runaway benzene nitration reaction were obtained based on the temperature-heat flow curve. In this embodiment, four exothermic temperature intervals were obtained by the programmed temperature calorimetry test. The first exothermic temperature interval was 25°C to 140°C, with a heat release of 384.3 J / g; the second exothermic temperature interval was 140°C to 170°C, with a heat release of 20 J / g; the third exothermic temperature interval was 195°C to 255°C, with a heat release of 135.3 J / g; and the fourth exothermic temperature interval was 260°C to 340°C, with a heat release of 287.3 J / g. Among them, the first exothermic interval is the main reaction interval of benzene nitration; the second exothermic interval is the out-of-control transition period; the third exothermic interval has a maximum heat release rate of 140mW, which is the first out-of-control interval of the benzene nitration process; the fourth exothermic interval has a maximum heat release rate of 80mW, which is the second out-of-control interval of the benzene nitration process.

[0108] Gas and liquid samples were collected at different stages of the programmed temperature calorimetry test and analyzed using GC / MS for composition and structure. Over 90% of the products in the main reaction zone were trinitrobenzene; over 40% of the products in the runaway transition period were trinitrobenzene disulfonic acid. The products in the primary runaway zone exhibited coking, with the primary functional groups being phenol, mercaptan, and nitro, and the gaseous products being NO and SO2. The products in the secondary runaway zone exhibited severe coking, with the primary functional groups being phenol and hydroxyl, and the gaseous products being NO2, NO, and N2.

[0109] Reaction molecular dynamics simulation is used to obtain the set of reaction runaway paths in each exothermic temperature range. Specifically, a closed-space three-dimensional molecular simulation system is first constructed based on the reactant and product components. The composition and number of molecules in the simulation system can be set and adjusted according to the actual situation. The molecular simulation system is subjected to energy minimization and kinetic equilibrium calculations to achieve equilibrium in the molecular system and obtain the initial state of the simulation. Then, the three-dimensional molecular simulation system is simulated and calculated using ReaxFF reaction molecular dynamics. The output data of the simulation calculation are analyzed to obtain the evolution results of the chemical molecules and the generated characteristic product molecules, and the molecular structure evolution is tracked to obtain the set of reaction runaway paths in each exothermic temperature range: ① Sulfonation of trinitrobenzene and sulfuric acid to form trinitrobenzene disulfonic acid; ② The nitro group of trinitrobenzene disulfonic acid abstracts the sulfonic hydrogen to form an ONOH functional group intermediate; ③ The CN bond of the trinitrobenzene disulfonic acid ONOH intermediate breaks to form ONOH, which then decomposes to form ON and OH; ④ The sulfonic acid radical of the trinitrobenzene disulfonic acid intermediate decomposes to form benzene pentad free radical and SO2; ⑤ The NO2 generated by the decomposition of trinitrobenzene reacts with the benzene free radical to form benzene triad free radical and NO, and the NO hydrogen abstraction decomposes to form OH free radical.

[0110] Quantum chemical density functional theory (DFT) was used to calculate the activation energy barriers and reaction exothermic characteristics of the microscopic reactions of chemical functional groups. The enthalpies and Gibbs free energies of reactants, products, intermediates, and transition states were determined, along with the microscopic activation energy barriers and reaction exotherms. Based on molecular dynamics and quantum chemical simulations, combined with product composition analysis, the marker molecule for the runaway transition phase of the benzene nitration reaction system was identified as trinitrobenzene disulfonic acid. The primary runaway marker molecules were phenol functional groups, NO, and SO₂, and the secondary runaway marker molecule was NO₂.

[0111] By monitoring the marker molecules and early temperature range of the benzene nitration reaction process, the out-of-control benzene nitration reaction can be quickly identified and suppressed at an early stage:

[0112] When the concentration of benzenesulfonic acid functional groups detected in the system begins to exceed 10%, or the temperature is between 140°C and 170°C (inclusive) and the average temperature rise rate within 10 minutes is greater than 0.35°C / min, the benzene nitration reaction is identified as being in the out-of-control transition period. Once the reaction system is identified as in the transition period, the process parameters should be adjusted promptly to return to the normal range.

[0113] When the detection concentration of phenol functional groups is greater than 15%, the detection concentration of NO is greater than 20ppm, and the detection concentration of SO2 is greater than 0.03mg / m 3, or when the temperature is between 170°C and 255°C (excluding 170°C and including 255°C) and the average temperature rise rate within 10 minutes is greater than 1.0°C / min, the identification result is that the benzene nitration reaction is in the early stage of a runaway reaction; when the identification result is in the early stage of a runaway reaction, cooling measures are taken for the target benzene nitration process to suppress the runaway reaction; and

[0114] If the detected NO2 concentration is greater than 10 ppm, or the temperature is above 255°C with an average temperature rise rate greater than 0.4°C / min over 10 minutes, the benzene nitration reaction is identified as being in the early stages of a secondary runaway. When this is the case, an emergency response is initiated for the target benzene nitration process.

[0115] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise form disclosed, and it is apparent that many changes and variations are possible in light of the foregoing teachings. The exemplary embodiments are selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and variations. Any simple modifications, equivalent variations, and modifications made to the exemplary embodiments described above are intended to fall within the scope of protection of the present invention.

Claims

1. A method for identifying an out-of-control benzene nitration reaction, characterized in that: The steps include: According to the target benzene nitration process, a trace benzene mixed acid system was established; A temperature-programmed test was performed on a trace benzene mixed acid system to obtain the exothermic temperature range and heat release during the runaway benzene nitration reaction, as well as information on reactants, intermediates, and products in each exothermic temperature range. Based on the information of reactants, intermediates and products in each exothermic temperature range, simulation calculations are performed using reaction molecular dynamics and quantum chemistry to obtain the set of reaction runaway paths and their thermodynamic data in each exothermic temperature range; Determine the key triggering steps and runaway marker molecules for each exothermic temperature interval based on the runaway reaction pathway set and thermodynamic data for each exothermic temperature interval; and The temperature of the benzene nitration reaction process of the target benzene nitration process and the determined out-of-control marker molecules are monitored, and the out-of-control benzene nitration reaction of the target benzene nitration process is identified based on the monitoring data.

2. The method for identifying an out-of-control benzene nitration reaction according to claim 1, wherein: Obtaining the set of reaction runaway paths for each exothermic temperature range includes: Based on the reactant and product information in each exothermic temperature range, a closed space three-dimensional molecular simulation system is constructed; Obtain the initial state of the three-dimensional molecular simulation system through energy minimization and dynamic equilibrium calculations; and ReaxFF was used to perform molecular dynamics simulations to obtain the molecular evolution results of reactants, intermediates, and products in each exothermic temperature interval, track the evolution of molecular structures, and obtain the set of reaction runaway paths in each exothermic temperature interval.

3. The method for identifying an out-of-control benzene nitration reaction according to claim 2, wherein: Obtaining thermodynamic data for each exothermic temperature interval includes: using quantum chemical density functional theory to simulate and calculate the microscopic reaction activation energy barrier and reaction exotherm in each exothermic temperature interval.

4. The method for identifying an out-of-control benzene nitration reaction according to claim 3, wherein: The exothermic reaction step with the smallest microscopic reaction activation energy barrier in the exothermic temperature range is regarded as the key initiating step for the runaway reaction in this exothermic temperature range.

5. The method for identifying an out-of-control benzene nitration reaction according to claim 4, wherein: The out-of-control marker molecule is determined based on the intermediate of the key initiating step of the reaction out of control.

6. The method for identifying an out-of-control benzene nitration reaction according to claim 1, wherein: The establishment of the trace benzene mixed acid system is to configure the trace benzene mixed acid system according to the benzene mixed acid system of the target benzene nitration process.

7. The method for identifying an out-of-control benzene nitration reaction according to claim 1, wherein: Reaction calorimetry was used to conduct programmed temperature test on trace mixed acid system.

8. The method for identifying an out-of-control benzene nitration reaction according to claim 7, wherein: The temperature range of the programmed temperature test is 25°C to 500°C.

9. The method for identifying an out-of-control benzene nitration reaction according to claim 8, wherein: The temperature increase interval of the programmed temperature test is 0.1°C to 2°C.

10. The method for identifying an out-of-control benzene nitration reaction according to claim 1, wherein: Identifying out-of-control benzene nitration reactions in the target benzene nitration process based on monitoring data includes: When the detected concentration of the benzenesulfonic acid functional group in the system is greater than the first concentration limit value, the identification result is that the benzene nitration reaction is in the out-of-control transition period; When the detected concentration of the phenol functional group is greater than the second concentration limit value or the detected concentration of NO is greater than the third concentration limit value, the identification result is that the benzene nitration reaction is in the early stage of a runaway reaction; and When the detected NO2 concentration is greater than the fifth limit value, the identification result is that the benzene nitration reaction is in the early stage of secondary runaway.

11. The method for identifying an out-of-control benzene nitration reaction according to claim 1, wherein: Identifying out-of-control benzene nitration reactions in the target benzene nitration process based on monitoring data includes: When the detected concentration of the benzenesulfonic acid functional group in the system is greater than the first concentration limit, or the temperature is within the first limit range and the average temperature rise rate within 10 minutes is greater than the first temperature rise limit, the identification result is that the benzene nitration reaction is in the runaway transition period; When the detected concentration of phenol functional groups is greater than the second concentration limit, the detected concentration of NO is greater than the third concentration limit, the detected concentration of SO2 is greater than the fourth concentration limit, or the temperature is within the second limit range and the average temperature rise rate within 10 minutes is greater than the second temperature rise limit, the identification result is that the benzene nitration reaction is in the early stage of a runaway reaction; and When the detected NO2 concentration is greater than the fifth limit value, or the temperature is higher than the temperature limit value and the average temperature rise rate within 10 minutes is greater than the third temperature rise limit value, the identification result is that the benzene nitration reaction is in the early stage of secondary runaway.

12. A method for suppressing runaway benzene nitration reaction, characterized in that: The steps include: The method for identifying an out-of-control benzene nitration reaction according to any one of claims 1 to 11 is used to identify an out-of-control benzene nitration reaction; When the identification result is an out-of-control transition period, adjust the process parameters to return to the normal range; When the identification result is an early stage of out-of-control, cooling measures are taken on the target benzene nitration process to suppress the out-of-control; as well as When the identification result is the early stage of secondary loss of control, an emergency response is initiated for the target benzene nitration process.

13. A system for identifying an out-of-control benzene nitration reaction, characterized in that: include: A reaction calorimeter is used to obtain all exothermic temperature ranges and heat releases of the benzene mixed acid system in the target benzene nitration process; A sample analyzer, which is used to obtain information about reactants, intermediates, and products in each exothermic temperature interval; A simulation analysis unit is used to obtain the reactant, intermediate and product information of each exothermic temperature interval, and to obtain the reaction runaway path set and its thermodynamic data of each exothermic temperature interval by using reaction molecular dynamics and quantum chemical simulation calculations, so as to determine the key triggering steps and runaway marker molecules of each exothermic temperature interval; and The out-of-control identification unit is used to monitor the temperature of the benzene nitration reaction process of the target benzene nitration process and the determined out-of-control marker molecules, and identify the out-of-control of the benzene nitration reaction of the target benzene nitration process based on the monitoring data.

14. The benzene nitration reaction out-of-control identification system according to claim 13, characterized in that: The sample analyzer is a chromatography-mass spectrometer and / or a Fourier transform infrared spectrometer.

15. The benzene nitration reaction out-of-control identification system according to claim 13, characterized in that: The out-of-control identification unit includes a temperature sensor and an infrared spectrum analyzer.

Images