An online assessment method for safety risk of fully mixed flow reactor operation

Abstract

The present invention provides an online assessment method for the safety risk of fully mixed flow reactor operation. The method is a risk assessment for the dynamic operation of exothermic reactions. The complete set of work includes defining the scope, collecting safety data, determining safety conditions and critical limits, and finally determining the coefficient indicating the safety deviation during the operation, that is, the real-time safety total index of the reactor. The method provides a real-time safety total index for evaluating the reactor temperature, while taking into account the reactor safety risk caused by the increase in reaction temperature and the reactor concentration accumulation safety risk caused by the decrease in reaction temperature, providing a warning for the operation of the reactor. The evaluation method is simple to implement. Compared with the traditional design-type reactor safety risk assessment, it can be used for the online assessment of the continuous operation safety risk of fully mixed flow reactors for exothermic reactions.

Description

Technical Field

[0001] The invention relates to the technical field of thermal safety risk assessment of chemical processes, and in particular to an online assessment method for operating safety risks of a fully mixed flow reactor. Background Art

[0002] Runaway chemical reactions are a major cause of major chemical accidents. If the thermal balance of the reaction device can be safely analyzed, and effective monitoring and timely warnings can be achieved, many accidents can be foreseen and avoided. At present, the risk assessment of chemical processes mainly includes two aspects: chemical substance safety and chemical process safety. Runaway chemical reactions specifically refer to the uncontrollable temperature rise process caused by the heat release of chemical reactions exceeding the heat extraction capacity of the device. Its research is subordinate to the thermal safety analysis of chemical reactions and is a key technology for chemical process safety risk assessment.

[0003] Most chemical reaction thermal safety analyses focus on risk assessment during the process design phase and after an accident occurs. Risks are avoided by adjusting the equipment structure size, operating procedures, and parameter settings of the process. In particular, steady-state continuous reactions are usually ensured by controlling the feed ratio and operating temperature, pressure, and cooling water flow. However, there are always load fluctuations and unknown disturbances in chemical production. Whether it is manual adjustment or automatic control response, it takes several overshoot steps to adjust the operating state back to a steady state. The process oscillations caused by these overshoots deviate from the steady-state safety point, which is a major safety hazard. Therefore, there is an urgent need for a reasonable online risk assessment technology to help operators evaluate the complete dynamic process so that they can respond as quickly as possible. Summary of the invention

[0004] The present invention aims at the deficiencies of the prior art and proposes an online assessment method for the operational safety risk of a fully mixed flow reactor. The method is used for dynamic operational risk assessment of exothermic reactions. The complete set of work includes defining the scope, collecting safety data, determining safety conditions and critical limits, and ultimately determining the safety deviation coefficient of the operating process - the real-time safety total index of the reactor.

[0005] The present invention is achieved through the following technical scheme, a method for online assessment of safety risks in operation of a fully mixed flow reactor, comprising the following steps:

[0006] (1) Define the scope of the target reactor, that is, determine the steady-state baseline operating condition of the target reactor, and its continuous one-hour reactor temperature The mean variation range is controlled within ±0.1°C, and the temperature fluctuation standard deviation is controlled within ±0.5°C; the object reactor is only used for the full mixed flow reactor (1), that is, it can be used for a single reactor or multiple reactors in full countercurrent operation;

[0007] (2) Collect the safety parameters of the target reactor, i.e. the steady-state reaction temperature Molar concentration of reactant A at reactant outlet (7) The molar concentration C of reactant A at the reactant feed port (6) A,in , collect the specific heat capacity C of the mixed material in the reactor P,mix , the density of the mixed material in the target reactor ρ mix , effective volume V of the target reactor, heat transfer capacity coefficient K and heat transfer area A of the target reactor, residence time τ of the target reactor, pre-exponential factor k0 of the Arrhenius reaction kinetic model, activation energy E, cooling water flow v CW , Cooling water inlet temperature T CW , cooling water specific heat capacity C P,CW and cooling water density ρ CW ;

[0008] (3) Determine the steady-state safety condition, that is, collect the maximum cooling water flow rate v when the cooling water valve of the reactor is fully open CW,max , used to calculate the maximum reactant A concentration under the corresponding steady-state conditions Maximum reaction temperature under steady state conditions Calculate the upper safety limit time of the target reactor under steady-state conditions And the object reactor safety lower limit time of steady state condition

[0009] (4) Determine the real-time safety condition, that is, collect the real-time reaction temperature of the reactor at time t Calculate the real-time concentration of the reactor at time t Calculate the real-time reactor safety upper limit time at time t and real-time safety lower limit time

[0010] (5) Solve the real-time safety index of a single reactor, including calculating the real-time safety upper limit index of a single object reactor at time t Real-time safety lower limit index of a single object reactor and the real-time safety index of a single object reactor Idx t ; The real-time safety total index Idx of each single object reactor t Calculate the real-time safety upper limit index of multiple object reactors at time t

[0011] Furthermore, the step (3) is specifically as follows:

[0012] (3.1) According to the maximum flow rate v of the collected cooling water CW,max , calculate the maximum heat transfer of the object reactor under steady-state conditions

[0013] Q ex,maxThe mathematical expression is as follows:

[0014]

[0015] (3.2) Calculate the maximum concentration of substance A that is safe and allowed under steady-state conditions Calculate the maximum reaction temperature allowed safely under steady-state conditions

[0016]

[0017] Where R is the ideal gas constant, ΔH r is the molar heat of reaction;

[0018] The utilization Calculate the maximum reaction temperature allowed safely under steady-state conditions The mathematical expression is as follows:

[0019]

[0020] (3.3) Define the upper safety limit time of a single object reactor under steady-state conditions as When cooling fails, the temperature inside the target reactor will rise to a critical point where even full cooling water cannot save the reactor. The time required is Current object reactor temperature The higher the value, the shorter the upper safety limit time and the smaller the upper safety limit; the steady-state reaction temperature Adiabatic temperature rise to maximum temperature Time The following formula can be used to solve:

[0021]

[0022] (3.4) Define the lower limit time of safety for a single reactor under steady-state conditions as When the reaction temperature drops, the concentration of raw material A increases, which will cause the reaction to run away. When the cooling fails, the target reactor will Under the condition of steady-state reaction temperature Adiabatic temperature rise to Time The following formula can be used for calculation:

[0023]

[0024] Furthermore, the step (4) is specifically as follows:

[0025] (4.1) Collect the real-time reaction temperature of the object reactor at time t

[0026] (4.2) Define the real-time safety upper limit time of a single object reactor at time t as When cooling fails, the time required for the temperature in the target reactor to rise to a critical value that cannot be saved even if the cooling water is fully turned on is The higher the current object reactor temperature, the shorter this time is and the smaller the safety upper limit is; the real-time reaction temperature Adiabatic temperature rise to maximum temperature Time The following formula can be used to solve:

[0027]

[0028] (4.3) Calculate the concentration of reactant A in the reactor at time t

[0029] The known function relationship of temperature changing with time is Solve the differential equation:

[0030]

[0031] Initial conditions: At t = 0, the reactor temperature is The molar concentration of reactant A is

[0032] (4.4) Define the lower limit time of safety for a single object reactor at time t as As the temperature drops, the concentration increases. When the cooling fails, the target reactor is under the current concentration condition. Under the condition of steady-state reaction temperature Adiabatic temperature rise to Time indication The following formula can be used for calculation:

[0033]

[0034] Furthermore, the step (5) is specifically as follows:

[0035] (5.1) Define the real-time safety upper limit index of a single object reactor at time t is the real-time safety upper limit of a single object reactor at time t Divide by the corresponding safety upper limit of the steady-state reactor

[0036]

[0037] (5.2) Define the real-time safety lower limit index of a single object reactor at time t is the real-time safety lower limit of a single object reactor at time t Divide by the corresponding safety lower limit of the object reactor under steady-state conditions

[0038]

[0039] (5.3) Define the real-time safety index Idx of a single object reactor at time t t Real-time safety lower limit index for a single object reactor and upper limit index The minimum value of

[0040]

[0041] (5.4) Define the real-time safety total index of multiple object reactors at time t The real-time safety index Idx of each object reactor t The product of .

[0042] The beneficial effects of the present invention are as follows:

[0043] The online evaluation method for operating safety risks of a continuous fully mixed flow reactor of the present invention can provide warnings for reactor operation and ensure safe and stable operation of the device; the online evaluation method for operating safety risks of a continuous fully mixed flow reactor of the present invention can be used in complex chemical processes; the online evaluation method for operating safety risks of a continuous fully mixed flow reactor of the present invention is convenient for measurement and has a simple implementation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a process block diagram of the online evaluation method for the safety risk of continuous full mixed flow reactor operation according to the present invention;

[0045] Figure 2 It is a schematic diagram of a fully mixed flow reactor in the continuous process of the present invention;

[0046] Figure 3 is the temperature T of the reactor of the present invention R (K), concentration of substance A in the reactor C A (kmol / m3) versus time t(hr);

[0047] Figure 4 is the real-time safety total index Idx of the reactor of the present invention t Graph showing changes with time t(hr).

[0048] Attached Figure 2 Description: 1-reactor; 2-jacket; 3-agitator; 4-cooling water pipe inlet; 5-cooling water pipe outlet; 6-reactant feed port; 7-reactant discharge port; 8-valve. DETAILED DESCRIPTION

[0049] In order to further illustrate the present invention, the following series of specific embodiments are given in conjunction with the accompanying drawings.

[0050] Figure 1 The flowchart of the online evaluation method for the safety risk of the continuous full mixed flow reactor operation is as follows: (1) defining the scope and judging whether the calculation object is applicable to the present invention; (2) collecting object data; (3) determining the steady-state safety condition of the object; (4) determining the dynamic safety condition of the object; (5) determining the upper and lower limit indexes of the object safety and determining the total safety index of the object.

[0051] Figure 2 It is a schematic diagram of a fully mixed flow reactor in a continuous process flow, which is composed of a fully mixed flow reactor 1, a jacket 2, an agitator 3, a cooling water pipeline inlet 4, a cooling water pipeline outlet 5, a reactant feed port 6, a reactant discharge port 7 and a valve 8;

[0052] The reactor 1 is a fully mixed flow reactor 1 used in the present invention, which is used to mix materials and is a place for performing exothermic reactions;

[0053] The jacket 2 is made of stainless steel and is used to pass cooling medium to perform heat exchange with the full mixed flow reactor 1, thereby controlling the temperature of the full mixed flow reactor 1;

[0054] The stirrer 3 is a stirring system composed of a motor, a sealed bearing and a stirring blade, which is used to mix the fluid in the kettle to promote the reaction;

[0055] The function of the valve 8 is to control the feed flow rate of the full mixed flow reactor 1;

[0056] That is, in the operation of the present invention, the reaction materials flow in from the reactant feed port 6 at the top of the fully mixed flow reactor 1 and flow out from the reactant discharge port 7 at the bottom, and the heat of reaction is taken away by the cooling water in the jacket 2. The safety parameters of the reactor to be collected and their measurement positions are marked in the figure for the calculation of the total safety index of the present invention.

[0057] Reference Figure 1-Figure 4 , an online assessment method for the safety risk of continuous full mixed flow reactor operation, comprising the following steps:

[0058] (1) Define the scope of the target reactor, that is, determine the steady-state baseline operating condition of the target reactor, and its continuous one-hour reactor temperature The mean variation range is controlled within ±0.1°C, and the temperature fluctuation standard deviation range is controlled within ±0.5°C; the object reactor is a full mixed flow reactor 1;

[0059] (2) Collect the safety parameters of the target reactor: the safety parameters include the steady-state reaction temperature Molar concentration of reactant A at reactant outlet 7 and the molar concentration C of reactant A at reactant feed port 6 A,in ; Collect the specific heat capacity C of the mixed material in the target reactor P,mix , the density of the mixed material in the target reactor ρ mix , effective volume V of the target reactor, heat transfer capacity coefficient K and heat transfer area A of the target reactor, residence time τ of the target reactor, pre-exponential factor k0 and activation energy E of the Arrhenius reaction kinetic model; cooling water flow v CW , Cooling water inlet temperature T CW , cooling water specific heat capacity C P,CW and cooling water density ρ CW ;

[0060] (3) Determine the steady-state safety condition: The steady-state safety condition includes the maximum cooling water flow rate v when the cooling water valve of the reactor is fully opened. CW,max , used to calculate the maximum concentration of the maximum reactant A under the corresponding steady-state condition Maximum reaction temperature under steady state conditions use Calculate the upper safety limit time of the target reactor under steady-state conditions And the object reactor safety lower limit time of steady state condition The fully mixed flow reactor can be a single fully mixed flow reactor 1 or multiple fully mixed flow reactors 1 running in full countercurrent.

[0061] The maximum flow rate v of the collected cooling water CW,max , calculate the maximum heat transfer Q of the object reactor under steady-state conditions ex,max The mathematical expression is as follows:

[0062]

[0063] The calculation of the maximum concentration of substance A allowed safely under steady-state conditions The mathematical expression is as follows:

[0064]

[0065] The utilization Calculate the maximum reaction temperature allowed safely under steady-state conditions The mathematical expression is as follows:

[0066]

[0067] Where R is the ideal gas constant; ΔH_r is the molar reaction heat;

[0068] The calculation of the upper limit time of the safety of the object reactor under steady-state conditions The mathematical expression is as follows:

[0069]

[0070] The object reactor safety lower limit time of the steady state condition The mathematical expression is as follows:

[0071]

[0072] (4) Determine real-time safety conditions: The real-time safety conditions include collecting the real-time reaction temperature of the target reactor at time t Calculate the real-time concentration of the object reactor at time t Calculate the safety upper limit time of the real-time object reactor at time t and real-time safety lower limit time

[0073] The calculation of the real-time object reactor safety upper limit time at time t The mathematical expression is as follows:

[0074]

[0075] The calculation of the real-time concentration of the object reactor at time t The differential equation is as follows:

[0076]

[0077] The calculation of the maximum cooling water flow v CW,max The maximum safe reaction temperature The mathematical expression is as follows:

[0078]

[0079] The calculation of the real-time safety lower limit time at time t The mathematical expression is as follows:

[0080]

[0081] (5) Solve the real-time safety index of a single object reactor, including calculating the real-time safety upper limit index of a single object reactor at time t Real-time safety lower limit index of a single object reactor and the real-time safety index of a single object reactor Idx t ; The real-time safety total index Idx of each single object reactor t Calculate the real-time safety upper limit index of multiple object reactors at time t

[0082] The calculation of the real-time safety upper limit index of a single object reactor at time t The mathematical expression is as follows:

[0083]

[0084] The real-time safety lower limit index of the single object reactor The mathematical expression is as follows:

[0085]

[0086] The single object reactor real-time safety total index Idx t The mathematical expression is as follows:

[0087]

[0088] Embodiment 1:

[0089] like Figure 2 In the continuous exothermic reaction process shown in the figure, the fully mixed flow reactor undergoes the reaction A+B=C+D. Equipment parameters: reactor type is fully mixed flow, effective reactor volume V=55m 3 , heat transfer coefficient KA = 36000 W / K, reactor residence time τ = 0.375 hr. Kinetic model: k0=5.139×10 3 m 3 / s, E = 1.5109 × 10 5 J / mol, process parameters: cooling water pipe inlet 4 temperature T CW =298.15K, maximum cooling water flow v CW,max =40m 3 / hr, steady-state reaction temperature under normal conditions Cooling water flow v CW =18.5m 3 / hr, the specific heat capacity of cooling water is assumed to be constant C P,CW =4.115J / g / K, cooling water density ρ CW =1000kg / m 3 , the concentration of substance A in the reactor feed is C A,in =3.242 kmol / m 3 The reactor temperature at time t is defined as Concentration of substance A in the reactor

[0090] (1) Ensure that the reactor is in continuous operation and the reactor temperature is kept constant for one hour under steady-state conditions. The mean change does not exceed ±0.1℃, and the standard deviation of temperature fluctuation does not exceed ±0.5℃;

[0091] (2) Collect and measure the steady-state normal operating reaction temperature The molar concentration of reactant A at the reactor outlet Reactor feed A substance concentration C A,in =3.242 kmol / m 3 , specific heat capacity C of the mixture in the reactor P,mix =114.33 J / mol / K, density ρ mix =27464.29mol / m 3 . Reactor effective volume V = 55m 3 The product of the reactor heat transfer capacity coefficient K and the heat transfer area A is KA = 36000 W / K, the reactor residence time τ = 0.375 hr, and the pre-exponential factor k0 of the first-order Arrhenius reaction kinetic model is 5.139 × 10 3 m 3 / s, activation energy E = 1.5109 × 10 5 J / mol; cooling water flow v CW =18.5m 3 / hr, cooling water inlet temperature T CW =298.15K, specific heat capacity of cooling water C P,CW =4.115J / g / K and cooling water density ρ CW =1000kg / m 3 ;

[0092] (3) Determine the steady-state safety condition and collect the maximum cooling water flow rate v when the reactor cooling water valve is fully open CW,max =40m 3 / hr, used to calculate the maximum reactant A concentration under the corresponding steady-state conditions Maximum reaction temperature under steady state conditions Calculate the upper safety limit time of the reactor under steady-state conditions and the lower safety limit of the reactor under steady-state conditions

[0093] According to the maximum flow rate v of the collected cooling water CW,max , calculate the maximum heat transfer Q of the reactor under steady-state conditions ex,max :

[0094]

[0095] Calculate the maximum concentration of substance A that is safe and permitted under steady-state conditions; Calculate the maximum reaction temperature allowed safely under steady-state conditions Where R is the ideal gas constant,

[0096]

[0097] Solve according to the following formula

[0098]

[0099]

[0100] The upper safety limit time of a single reactor under steady-state conditions is defined as When cooling fails, the temperature in the reactor rises to a critical value that cannot be saved by fully opening the cooling water. The time required is The higher the current reactor temperature, the shorter this time is, the smaller the safety upper limit is, and the steady-state reaction temperature is Adiabatic temperature rise to maximum temperature Time Solve using the following formula:

[0101]

[0102] The lower limit time of safety for a single reactor under steady-state conditions is defined as As the temperature drops, the concentration increases. When the cooling fails, the reactor is at the current concentration condition. Under the condition of steady-state reaction temperature Adiabatic temperature rise to The time representation can be calculated using the following formula:

[0103]

[0104] (4) Determine the real-time safety conditions and collect the real-time reaction temperature of the reactor at time t Calculate the real-time concentration of the reactor at time t Calculate the real-time reactor safety upper limit time at time t and real-time safety lower limit time

[0105] (a) Collect and measure the reaction temperature of the reactor at time t over a period of time

[0106] Table 1

[0107]

[0108]

[0109] (b) Define the real-time safety upper limit time of a single reactor at time t as It is expressed as the time required for the temperature in the reactor to rise to the critical value where full cooling water cannot save the reactor when cooling fails. The higher the current reactor temperature, the shorter this time and the smaller the safety upper limit. Real-time reaction temperature Adiabatic temperature rise to maximum temperature Time The following formula can be used to solve:

[0110]

[0111] Take t = 1.1 hr as an example;

[0112]

[0113] Similarly, complete all time points in Table 1 calculate:

[0114] Table 2

[0115]

[0116]

[0117] (c) Temperature as a function of time for

[0118]

[0119] Solve the differential equation:

[0120]

[0121] Initial conditions: When t = 1.0 hr, the reactor temperature is The molar concentration of reactant A is kmol / m 3 ; The concentration corresponding to the reaction temperature is shown in Table 3 below, and the trend of the results can be seen Figure 3 .

[0122] Table 3

[0123]

[0124]

[0125] Depend on Figure 3 It can be seen that when the reactor temperature drops, the concentration of reactants will accumulate. When the reactor temperature returns to the set value for the first time, the concentration of reactants is still in a relatively high range, which may pose a thermal safety risk.

[0126] (d) Calculate the maximum cooling water flow v CW,max The maximum safe reaction temperature Solution

[0127]

[0128] Take t = 1.1 hr as an example:

[0129]

[0130] (e) Define the lower limit of safety time for a single reactor at time t as As the temperature drops, the concentration increases. When the cooling fails, the reactor is at the current concentration condition. Under the condition of steady-state reaction temperature Adiabatic temperature rise to Time indication The following formula can be used for calculation:

[0131]

[0132] Take t = 1.1 hr as an example

[0133]

[0134]

[0135] Similarly, complete all time points in Table 1 calculate;

[0136] Table 4

[0137]

[0138]

[0139] (5) Solve the real-time safety index of a single reactor, including calculating the real-time safety upper limit index of a single reactor at time t Real-time safety lower limit index of a single reactor and the real-time safety index of a single reactor Idx t ;

[0140] (a) The real-time safety index of a single reactor is defined as follows: is the real-time safety upper limit of a single reactor at time t Divide by the corresponding safety upper limit of the steady-state reactor Take t = 1.1 hr as an example:

[0141]

[0142] (b) Real-time safety lower limit index of a single reactor is the real-time safety lower limit of a single reactor at time t Divide by the corresponding safety lower limit of the steady-state reactor Take t=1.1 as an example:

[0143]

[0144] (c) Real-time safety index Idx of a single reactor at time t t Real-time safety lower limit index for a single reactor and upper limit index The minimum value, taking t = 1.1hr as an example:

[0145]

[0146] Similarly, complete all the time points Idx in Table 1 t Calculation, the result trend is visible Figure 4 .

[0147]

[0148]

[0149] Table 5

[0150] from Figure 4 Idx t It can be seen from the changes in Idx that at time t = 1 hr, the reactor temperature changes significantly, the safety factor decreases, and the reaction safety deteriorates. The combined effect of temperature and concentration is the largest at 1.8 hr, Idx t Reduced to 0.144. If 0.6 is the alarm low limit and 0.4 is the alarm low-low limit, then at t=1.25hr a low limit alarm should be given, requiring operator intervention. At t=1.45hr a low-low limit alarm should be given, requiring operator intervention.

[0151] The contents described in the embodiments of this specification are merely an enumeration of implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also includes equivalent technical means that can be thought of by those skilled in the art based on the inventive concept.

Claims

1. A method for online assessment of safety risks in fully mixed flow reactor operation, characterized in that: The following steps are involved: (1) Define the scope of the target reactor, that is, determine the steady-state baseline operating condition of the target reactor, and its continuous one-hour reactor temperature The mean variation range is controlled within ±0.1°C, and the temperature fluctuation standard deviation is controlled within ±0.5°C; the object reactor is only used for a full mixed flow reactor (1), that is, it can be used for a single reactor or multiple reactors in full countercurrent operation; (2) Collect the safety parameters of the target reactor, i.e. the steady-state reaction temperature Molar concentration of reactant A at reactant outlet (7) The molar concentration C of reactant A at the reactant feed port (6) A,in , collect the specific heat capacity C of the mixed material in the reactor P,mix , the density of the mixed material in the target reactor ρ mix , effective volume V of the target reactor, heat transfer capacity coefficient K and heat transfer area A of the target reactor, residence time τ of the target reactor, pre-exponential factor k0 of the Arrhenius reaction kinetic model, activation energy E, cooling water flow v CW , Cooling water inlet temperature T CW , cooling water specific heat capacity C P,CW and cooling water density ρ CW ; (3) Determine the steady-state safety condition, that is, collect the maximum cooling water flow rate v when the cooling water valve of the reactor is fully open CW,max , used to calculate the maximum reactant A concentration under the corresponding steady-state conditions Maximum reaction temperature under steady state conditions Calculate the upper safety limit time of the target reactor under steady-state conditions And the object reactor safety lower limit time of steady state condition (4) Determine the real-time safety condition, that is, collect the real-time reaction temperature of the reactor at time t Calculate the real-time concentration of the reactor at time t Calculate the real-time reactor safety upper limit time at time t and real-time safety lower limit time (5) Solve the real-time safety index of a single reactor, including calculating the real-time safety upper limit index of a single object reactor at time t Real-time safety lower limit index of a single object reactor and the real-time safety index of a single object reactor Idx t ; The real-time safety total index Idx of each single object reactor t Calculate the real-time safety upper limit index of multiple object reactors at time t 2. The method for online assessment of safety risk of fully mixed flow reactor operation according to claim 1, characterized in that: The step (3) is specifically: (3.1) According to the maximum flow rate v of the collected cooling water CW,max , calculate the maximum heat transfer Q of the object reactor under steady-state conditions ex,max The mathematical expression is as follows: (3.2) Calculate the maximum concentration of substance A that is safe and allowed under steady-state conditions Calculate the maximum reaction temperature allowed safely under steady-state conditions Where R is the ideal gas constant, ΔH r is the molar heat of reaction; The utilization Calculate the maximum reaction temperature allowed safely under steady-state conditions The mathematical expression is as follows: (3.3) Define the upper safety limit time of a single object reactor under steady-state conditions as When cooling fails, the temperature inside the reactor will rise to a critical point where even full cooling water cannot save the reactor. The time required is Current object reactor temperature The higher the value, the shorter the upper safety limit time and the smaller the upper safety limit; the steady-state reaction temperature Adiabatic temperature rise to maximum temperature Time The following formula can be used to solve: (3.4) Define the lower limit time of safety for a single reactor under steady-state conditions as When the reaction temperature drops, the concentration of raw material A increases, which will cause the reaction to run away. When the cooling fails, the target reactor will Under the condition of steady-state reaction temperature Adiabatic temperature rise to Time The following formula can be used for calculation:

3. The method for online assessment of safety risk of fully mixed flow reactor operation according to claim 1, characterized in that: The step (4) is specifically: (4.1) Collect the real-time reaction temperature of the object reactor at time t (4.2) Define the real-time safety upper limit time of a single object reactor at time t as When cooling fails, the time required for the temperature in the target reactor to rise to a critical value that cannot be saved even if the cooling water is fully turned on is The higher the current object reactor temperature, the shorter this time is and the smaller the safety upper limit is; the real-time reaction temperature Adiabatic temperature rise to maximum temperature Time The following formula can be used to solve: (4.3) Calculate the concentration of reactant A in the reactor at time t The known function relationship of temperature changing with time is Solve the differential equation: Initial conditions: At t = 0, the reactor temperature is The molar concentration of reactant A is (4.4) Define the lower limit time of safety for a single object reactor at time t as As the temperature drops, the concentration increases. When the cooling fails, the target reactor is under the current concentration condition. Under the condition of steady-state reaction temperature Adiabatic temperature rise to Time indication The following formula can be used for calculation:

4. The method for online assessment of safety risk of fully mixed flow reactor operation according to claim 1, characterized in that: The step (5) is specifically: (5.1) Define the real-time safety upper limit index of a single object reactor at time t is the real-time safety upper limit of a single object reactor at time t Divide by the corresponding safety upper limit of the steady-state reactor (5.2) Define the real-time safety lower limit index of a single object reactor at time t is the real-time safety lower limit of a single object reactor at time t Divide by the corresponding safety lower limit of the object reactor under steady-state conditions (5.3) Define the real-time safety index Idx of a single object reactor at time t t Real-time safety lower limit index for a single object reactor and upper limit index The minimum value of (5.4) Define the real-time safety total index of multiple object reactors at time t The real-time safety index Idx of each object reactor t The product of .

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