Calculation method of release volume under uncontrolled reactor reaction conditions

Abstract

The present invention discloses a method for calculating the discharge volume under the condition of reactor reaction out of control, including: determining the cause of the reactor reaction out of control; determining the composition of the test sample used to test the out-of-control reaction according to the cause of the out-of-control, and establishing the macroscopic reaction equation of the out-of-control reaction; establishing an equivalent simulation process for the reactor production process; using the equivalent simulation process to simulate the reactor reaction out of control condition, using macroscopic kinetic parameters and the macroscopic reaction equation of the out-of-control reaction to simulate the out-of-control reaction, and obtaining the change data of the reactor pressure over time and the change data of the material parameter change rate at each position of the reactor over time; calculating the total discharge volume of the reactor according to the change data of the reactor pressure over time and the change data of the material parameter change rate at each position of the reactor over time. The present invention ensures that the calculated discharge volume is more accurate, so that the investment of the safety discharge device and the post-processing system is greatly reduced, and the operation of the safety device is more reliable.

Description

Technical Field

[0001] The invention relates to the technical field of chemical engineering, and in particular to a method for calculating the discharge volume of a reactor under an out-of-control reaction condition. Background Art

[0002] In recent years, with the vigorous development of my country's chemical industry, new synthesis processes and routes have been continuously put into industrial production, and the accidents of equipment over-temperature and over-pressure caused by uncontrolled reactions have become more and more frequent. As a recognized effective means of protecting against uncontrolled reactions, safety relief devices can promptly remove materials or energy from the reactor when the reaction is out of control to avoid equipment over-pressure rupture. The difficulty of using safety relief devices to protect reactors from uncontrolled overpressure reactions lies in the accurate calculation of the release volume, especially for reactors that still have material inflow and outflow when the uncontrolled reaction occurs.

[0003] Patent CN108563809A discloses a method for calculating the discharge volume of a liquefied petroleum gas storage tank pressure relief system. This method calculates the discharge volume under fire conditions of a liquefied petroleum gas storage tank and does not involve chemical reactions.

[0004] The Design Institute for Emergency Release Systems (DIERS) under the American Institute of Chemical Engineers (AIChE) has proposed a method to calculate the release volume of a runaway reaction directly through thermal safety data. However, the calculation method proposed by DIERS is only applicable to intermittently operated reactors. Moreover, the calculation method proposed by DIERS is a conservative calculation method that uses the maximum temperature rise rate and pressure rise rate caused by a runaway reaction. Using the calculation method proposed by DIERS for release design will greatly increase the cost investment of the release post-treatment system.

[0005] However, the existing method for calculating the release volume caused by reaction runaway is too conservative, and the scenario with continuous material inflow and outflow during reaction runaway can only be converted into an intermittent scenario for calculating the release volume. Summary of the invention

[0006] Based on this, it is necessary to provide a method for calculating the release amount under reactor reaction out-of-control conditions to address the technical problems that the existing methods for calculating the release amount caused by reaction out-of-control are too conservative and that the scenario with continuous material input and output can only be converted into an intermittent scenario for release amount calculation when the reaction is out of control.

[0007] The present invention provides a method for calculating the discharge amount under the condition of out-of-control reaction of a reactor, comprising:

[0008] When the reactor reaction is out of control, determine the cause of the out-of-control reaction;

[0009] Determine the composition of a test sample for testing a runaway reaction according to the cause of the runaway reaction, perform a test reaction on the test sample to obtain a test product, obtain a reaction heat measurement value and macroscopic kinetic parameters obtained in the test, and establish a macroscopic reaction equation of the runaway reaction according to the test product and the reaction heat measurement value;

[0010] Establishing an equivalent simulation process for the reactor production process;

[0011] The equivalent simulation process is used to simulate the runaway reaction condition of the reactor, and the macroscopic kinetic parameters and the macroscopic reaction equation of the runaway reaction are used to simulate the runaway reaction to obtain the change data of the reactor pressure over time and the change data of the change rate of the material parameters at each position of the reactor over time;

[0012] The total discharge volume of the reactor is calculated based on the data of changes in the reactor pressure over time and the data of changes in the rate of change of material parameters at each position of the reactor over time.

[0013] Furthermore, the equivalent simulation process divides the reactor into a plurality of micro-elements, and the rate of change of material parameters at each position of the reactor is the rate of change of parameters of the materials included in each micro-element of the reactor.

[0014] Furthermore, the total discharge volume of the reactor is calculated based on the change data of the reactor pressure over time and the change data of the material parameter change rate at each position of the reactor over time, specifically including:

[0015] The total discharge volume and the maximum discharge volume of the reactor at different sampling times are calculated based on the data of changes in the reactor pressure over time and the data of changes in the rate of change of material parameters at each position of the reactor over time.

[0016] Furthermore, the parameter change rate is the density change rate, and the total discharge amount and the maximum discharge amount of the reactor at different sampling times are calculated according to the change data of the reactor pressure over time and the change data of the material parameter change rate at each position of the reactor over time, specifically including:

[0017] The total discharge volume of the reactor at sampling time t is calculated as:

[0018]

[0019] The maximum discharge volume is calculated as:

[0020] W max =max(W t )

[0021] Where: W t is the total discharge of the reactor at sampling time t, n is the number of micro-elements divided into the reactor, V i is the volume of the ith infinitesimal element, is the density change rate of the ith element at sampling time t, The time when the reactor pressure first reaches the set pressure of the reactor safety relief device, W max The maximum discharge volume.

[0022] Further, the macroscopic reaction equation of the runaway reaction is established according to the test product and the reaction heat measurement value, specifically including:

[0023] Compensating the test product according to the difference between the molar amount of the substance contained in the test sample and the molar amount of the substance contained in the test product;

[0024] Generate an initial macroscopic reaction equation of the runaway reaction according to the compensated test product and the test sample;

[0025] The calculated value of the reaction heat of the initial macroscopic reaction equation is determined by bond energy calculation. The initial macroscopic reaction equation is corrected according to the calculated value of the reaction heat of the initial macroscopic reaction equation and the measured value of the reaction heat. The corrected macroscopic reaction equation is used as the macroscopic reaction equation of the runaway reaction.

[0026] Furthermore, the compensating the test product according to the difference between the molar amount of the substance contained in the test sample and the molar amount of the substance contained in the test product specifically includes:

[0027] Atomic balance compensation is performed on each element contained in the test product, and the atomic balance compensation is:

[0028] Calculate the molar difference between the molar amount of atoms of the element in the test sample and the molar amount of atoms of the element in the test product;

[0029] The compensation amount of each type of substance containing atoms of the element in the test product is calculated according to the molar weight difference, and the substances containing atoms of the element in the test product are compensated using the compensation amount.

[0030] Furthermore, the test sample contains carbon, oxygen, hydrogen, and / or other miscellaneous elements, and performing atomic balance compensation on each element contained in the test product specifically includes:

[0031] A carbon element compensation step, if the test product contains carbon element, then the carbon element atomic balance compensation is performed on the substance containing carbon element in the test sample, and then it is determined whether the test product contains impurity elements. If the test product contains impurity elements, then the impurity element compensation step is performed on the test product after the carbon element atomic balance compensation is performed, otherwise, the hydrogen and oxygen compensation step is performed on the test product after the carbon element atomic balance compensation is performed;

[0032] The impurity element compensation step is to perform atomic balance compensation of impurity elements on the substance containing impurity elements in the test product, and then determine whether the test product after the atomic balance compensation of impurity elements is still missing oxygen atoms or hydrogen atoms compared with the test sample. If missing, perform the hydrogen-oxygen compensation step, otherwise end;

[0033] A hydrogen-oxygen compensation step is performed on the water molecules in the test product, and the atomic balance compensation of the oxygen element is performed on the test product for which the atomic balance compensation of the hydrogen element is performed, or the atomic balance compensation of the oxygen element is performed on the water molecules in the test product, and the atomic balance compensation of the hydrogen element is performed on the test product for which the atomic balance compensation of the oxygen element is performed.

[0034] Furthermore, the initial macroscopic reaction equation is corrected according to the calculated reaction heat value of the initial macroscopic reaction equation and the measured reaction heat value, and the corrected macroscopic reaction equation is used as the macroscopic reaction equation of the runaway reaction, specifically including:

[0035] Selecting one possible reaction as a selected reaction from the possible reactions occurring between molecules in the product of the initial macro-reaction equation, and modifying the initial macro-reaction equation successively, wherein in each modification, in the product of the macro-reaction equation, the reactants of the selected reaction are replaced by the products of the product;

[0036] After each correction of the initial macroscopic reaction equation, the calculated value of the reaction heat of the corrected macroscopic reaction equation is calculated. If the difference between the calculated value of the reaction heat of the macroscopic reaction equation after the reaction and the measured value of the reaction heat is within a preset range, the macroscopic reaction equation after the reaction is selected as the macroscopic reaction equation of the runaway reaction. Otherwise, continue to rotate the next possible reaction and correct the corrected macroscopic reaction equation again.

[0037] Furthermore, the possible reactions include: a dehydration reaction of an organic substance, a reverse reaction of the dehydration reaction of an organic substance, a reaction of oxygen molecules and hydrogen molecules generating water molecules, and / or a reaction of water molecules decomposing into oxygen molecules and hydrogen molecules.

[0038] Furthermore, the establishment of an equivalent simulation process for the reactor production process specifically includes:

[0039] Obtain the status of all automatic control valves when the reactor reaction is out of control;

[0040] An equivalent simulation process for the reactor production process is established to keep the automatic control valves other than those affected by the out-of-control cause in the state when the reactor reaction is out of control.

[0041] According to the cause of the runaway reaction, the present invention performs a thermal safety test on the sample to obtain the kinetic parameters of the runaway reaction and establish a macroscopic reaction equation, and uses process simulation software to obtain the change of each parameter over time and calculate the discharge volume according to the simulation data. Compared with the traditional method, the method provided by the present invention can clearly express the change of temperature, pressure and other parameters in the reactor at each moment when the runaway reaction occurs; compared with the traditional method of converting the continuous working condition into the intermittent working condition and then calculating the discharge volume, the discharge volume can be calculated under the condition of considering the discharge of the reactor, and when obtaining the data on the change rate of the parameters required for the discharge calculation over time, relying on the powerful physical property database of the process simulation software, it is ensured that the calculated discharge volume is more accurate, closer to the actual and far less than the value calculated by the traditional discharge volume calculation method, so that the investment in the safety discharge device and the post-processing system is greatly reduced, and the operation of the safety device is more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a working flow chart of a method for calculating the discharge amount under a reactor reaction out-of-control condition according to an embodiment of the present invention;

[0043] Figure 2 This is a working flow chart of a method for calculating the discharge amount under a reactor reaction out-of-control condition in another embodiment of the present invention;

[0044] Figure 3 A flowchart of a method for calculating the discharge amount of a continuously operated full liquid phase reactor under uncontrolled reaction conditions in the best embodiment of the present invention;

[0045] Figure 4 A virtual reaction established for the method for calculating the discharge amount under the uncontrolled reaction condition of the continuously operated full liquid phase reactor of the best embodiment of the present invention;

[0046] Figure 5 An equivalent simulation process established for the method for calculating the discharge volume under the uncontrolled reaction condition of the continuously operated full liquid phase reactor of the best embodiment of the present invention;

[0047] Figure 6 The dynamic simulation results of the out-of-control parameters of the method for calculating the discharge volume under the out-of-control reaction condition of the continuously operated full liquid phase reactor of the best embodiment of the present invention;

[0048] Figure 7 The discharge volume calculation result of the discharge volume calculation method under the condition of out-of-control reaction of the continuously operated full liquid phase reactor of the best embodiment of the present invention is shown. DETAILED DESCRIPTION

[0049] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. The same components are represented by the same reference numerals. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0050] like Figure 1 The flowchart of a method for calculating the discharge amount under a reactor out-of-control reaction condition according to an embodiment of the present invention is shown, comprising:

[0051] Step S101, when the reactor reaction is out of control, determining the cause of the out of control reaction of the reactor;

[0052] Step S102, determining the composition of a test sample for testing a runaway reaction according to the runaway cause, performing a test reaction on the test sample to obtain a test product, obtaining a reaction heat measurement value and macroscopic kinetic parameters obtained by the test, and establishing a macroscopic reaction equation of the runaway reaction according to the test product and the reaction heat measurement value;

[0053] Step S103, establishing an equivalent simulation process for the reactor production process;

[0054] Step S104, using the equivalent simulation process to simulate the runaway reaction condition of the reactor, using the macroscopic kinetic parameters and the macroscopic reaction equation of the runaway reaction to simulate the runaway reaction, and obtaining the change data of the reactor pressure over time and the change data of the material parameter change rate at each position of the reactor over time;

[0055] Step S105, calculating the total discharge volume of the reactor according to the data of changes in the reactor pressure over time and the data of changes in the rate of change of material parameters at each position of the reactor over time.

[0056] Specifically, the present invention is preferably applied to a continuously operated full liquid phase reactor. First, step S101 is performed to determine the cause of the reactor, such as the continuously operated full liquid phase reactor, in which the reaction is out of control. The cause of the reaction out of control includes, but is not limited to: the initial reaction temperature is too high, the initial reaction temperature is too low, too much material is added, too little material is added, too much catalyst is added, too little catalyst is added, cooling failure or external fire, feeding error, instrument air interruption, reaction pressure is too high, reaction pressure is too low, internal leakage of heat exchange equipment, etc.

[0057] Then, step S102 is performed to determine the composition of the test sample used to test and establish the runaway reaction according to the cause of the runaway reaction. The runaway reaction is a chemical reaction that causes the runaway reaction. The composition of the test sample is determined according to the cause of the runaway reaction. For example, the main reaction occurring in the reactor is cumene hydroperoxide (CHP, raw material A) oxidizing propylene to generate propylene oxide. The cause of the runaway reaction is that CHP is catalytically decomposed in an adiabatic fixed bed reactor, causing the pressure and temperature of the adiabatic fixed bed reactor to rise. The runaway reaction is a catalytic decomposition reaction of CHP, and the test sample is a cumene solution of CHP. Then the test sample is subjected to a test reaction to obtain a test product, and the reaction heat measurement value and macroscopic kinetic parameters obtained by the test are obtained, and a macroscopic reaction equation of the runaway reaction is established according to the test product and the reaction heat measurement value. Preferably, a thermal safety test instrument is used to obtain the temperature rise rate of the test sample when the reaction liquid in the reactor is out of control, and the reaction heat measurement value and macroscopic kinetic parameters of the runaway reaction are calculated. Macroscopic kinetic parameters include reaction order n, activation energy Ea, and pre-exponential factor A. A macroscopic reaction equation of the runaway reaction is established based on the test product and the reaction heat measurement value.

[0058] Then, step S103 is performed to establish an equivalent simulation process of the reactor production process. Specifically, a process simulation software can be used to establish a process flow, such as an equivalent simulation process of a continuously operated full liquid phase reactor. The process simulation software includes but is not limited to Aspen, Hysys, and PROII.

[0059] Then, step S104 is executed to dynamically simulate the out-of-control parameters. Based on the macroscopic reaction equation and macroscopic kinetic parameters of the out-of-control reaction established in step S102, the equivalent simulation process established in step S103 is used to simulate the out-of-control reaction condition of the reactor, and the change data of the reactor pressure over time and the change data of the material parameter change rate at each position of the continuously operated full liquid phase reactor over time are obtained. The material parameter change rate is preferably the material density change rate.

[0060] Finally, step S105 is executed to calculate the total discharge volume. The total discharge volume of the reactor is calculated based on the change data of the reactor pressure over time obtained in step S104 and the change data of the change rate of the material parameters at each position of the reactor over time.

[0061] Preferably, when designing the reactor discharge system, the discharge caliber of the required safety discharge facility and various design parameters of the post-discharge treatment system are determined based on the calculated total discharge volume of the reactor.

[0062] According to the cause of the runaway reaction, the present invention performs a thermal safety test on the sample to obtain the kinetic parameters of the runaway reaction and establish a macroscopic reaction equation, and uses process simulation software to obtain the change of each parameter over time and calculate the discharge volume according to the simulation data. Compared with the traditional method, the method provided by the present invention can clearly express the change of temperature, pressure and other parameters in the reactor at each moment when the runaway reaction occurs; compared with the traditional method of converting the continuous working condition into the intermittent working condition and then calculating the discharge volume, the discharge volume can be calculated under the condition of considering the discharge of the reactor, and when obtaining the data on the change rate of the parameters required for the discharge calculation over time, relying on the powerful physical property database of the process simulation software, it is ensured that the calculated discharge volume is more accurate, closer to the actual and far less than the value calculated by the traditional discharge volume calculation method, so that the investment in the safety discharge device and the post-processing system is greatly reduced, and the operation of the safety device is more reliable.

[0063] like Figure 2 The flowchart is a method for calculating the discharge amount under the condition of out-of-control reaction of a reactor in another embodiment of the present invention, comprising:

[0064] Step S201, when the reactor reaction is out of control, determining the cause of the out-of-control reaction of the reactor.

[0065] In one embodiment, the causes of the loss of control include but are not limited to: the initial reaction temperature is too high, the initial reaction temperature is too low, too much material is added, too little material is added, too much catalyst is added, too little catalyst is added, cooling failure or external fire, feeding error, instrument air interruption, reaction pressure is too high, reaction pressure is too low, and internal leakage of heat exchange equipment.

[0066] Step S202, determining the composition of a test sample for testing a runaway reaction according to the cause of the runaway reaction, performing a test reaction on the test sample to obtain a test product, obtaining a reaction heat measurement value and macroscopic kinetic parameters obtained in the test, and establishing a macroscopic reaction equation of the runaway reaction according to the test product and the reaction heat measurement value.

[0067] In one embodiment, the macroscopic reaction equation of the runaway reaction is established according to the test product and the reaction heat measurement value, specifically comprising:

[0068] Compensating the test product according to the difference between the molar amount of the substance contained in the test sample and the molar amount of the substance contained in the test product;

[0069] Generate an initial macroscopic reaction equation of the runaway reaction according to the compensated test product and the test sample;

[0070] The calculated value of the reaction heat of the initial macroscopic reaction equation is determined by bond energy calculation. The initial macroscopic reaction equation is corrected according to the calculated value of the reaction heat of the initial macroscopic reaction equation and the measured value of the reaction heat. The corrected macroscopic reaction equation is used as the macroscopic reaction equation of the runaway reaction.

[0071] In one embodiment, compensating the test product according to the difference between the molar amount of the substance contained in the test sample and the molar amount of the substance contained in the test product specifically includes:

[0072] Atomic balance compensation is performed on each element contained in the test product, and the atomic balance compensation is:

[0073] Calculate the molar difference between the molar amount of atoms of the element in the test sample and the molar amount of atoms of the element in the test product;

[0074] The compensation amount of each type of substance containing atoms of the element in the test product is calculated according to the molar weight difference, and the substances containing atoms of the element in the test product are compensated using the compensation amount.

[0075] In one embodiment, the test sample contains carbon, oxygen, hydrogen, and / or other miscellaneous elements, and performing atomic balance compensation on each element contained in the test product specifically includes:

[0076] A carbon element compensation step, if the test product contains carbon element, then the carbon element atomic balance compensation is performed on the substance containing carbon element in the test sample, and then it is determined whether the test product contains impurity elements. If the test product contains impurity elements, then the impurity element compensation step is performed on the test product after the carbon element atomic balance compensation is performed, otherwise, the hydrogen and oxygen compensation step is performed on the test product after the carbon element atomic balance compensation is performed;

[0077] The impurity element compensation step is to perform atomic balance compensation of impurity elements on the substance containing impurity elements in the test product, and then determine whether the test product after the atomic balance compensation of impurity elements is still missing oxygen atoms or hydrogen atoms compared with the test sample. If missing, perform the hydrogen-oxygen compensation step, otherwise end;

[0078] A hydrogen-oxygen compensation step is performed on the water molecules in the test product, and the atomic balance compensation of the oxygen element is performed on the test product for which the atomic balance compensation of the hydrogen element is performed, or the atomic balance compensation of the oxygen element is performed on the water molecules in the test product, and the atomic balance compensation of the hydrogen element is performed on the test product for which the atomic balance compensation of the oxygen element is performed.

[0079] In one embodiment, the initial macroscopic reaction equation is corrected according to the calculated reaction heat value of the initial macroscopic reaction equation and the measured reaction heat value, and the corrected macroscopic reaction equation is used as the macroscopic reaction equation of the runaway reaction, specifically including:

[0080] Selecting one possible reaction as a selected reaction from the possible reactions occurring between molecules in the product of the initial macro-reaction equation, and modifying the initial macro-reaction equation successively, wherein in each modification, in the product of the macro-reaction equation, the reactants of the selected reaction are replaced by the products of the product;

[0081] After each correction of the initial macroscopic reaction equation, the calculated value of the reaction heat of the corrected macroscopic reaction equation is calculated. If the difference between the calculated value of the reaction heat of the macroscopic reaction equation after the reaction and the measured value of the reaction heat is within a preset range, the macroscopic reaction equation after the reaction is selected as the macroscopic reaction equation of the runaway reaction. Otherwise, continue to rotate the next possible reaction and correct the corrected macroscopic reaction equation again.

[0082] In one embodiment, the possible reactions include: a dehydration reaction of an organic substance, a reverse reaction of the dehydration reaction of an organic substance, a reaction of oxygen molecules and hydrogen molecules generating water molecules, and / or a reaction of water molecules decomposing into oxygen molecules and hydrogen molecules.

[0083] Step S203, establishing an equivalent simulation process for the reactor production process, wherein the equivalent simulation process divides the reactor into a plurality of micro-elements.

[0084] In one embodiment, the establishment of an equivalent simulation process for the reactor production process specifically includes:

[0085] Obtain the status of all automatic control valves when the reactor reaction is out of control;

[0086] An equivalent simulation process for the reactor production process is established to keep the automatic control valves other than those affected by the out-of-control cause in the state before the reactor reaction goes out of control.

[0087] Step S204, using the equivalent simulation process to simulate the runaway reaction condition of the reactor, using the macroscopic kinetic parameters and the macroscopic reaction equation of the runaway reaction to simulate the runaway reaction, and obtaining the change data of the reactor pressure over time and the change data of the density change rate of the materials included in each microelement of the reactor over time.

[0088] Step S205, calculating the total discharge volume and the maximum discharge volume of the reactor at different sampling times according to the change data of the reactor pressure over time and the change data of the material parameter change rate at each position of the reactor over time, specifically:

[0089] The total discharge volume of the reactor at sampling time t is calculated as:

[0090]

[0091] The maximum discharge volume is calculated as:

[0092] W max =max(W t )

[0093] Where: W t is the total discharge of the reactor at sampling time t, n is the number of micro-elements divided into the reactor, V i is the volume of the ith infinitesimal element, is the density change rate of the ith element at sampling time t, The time when the reactor pressure first reaches the set pressure of the reactor safety relief device, W max The maximum discharge volume.

[0094] Specifically, in step S201, the cause of the reactor reaction runaway is determined. The reactor is preferably a continuously operated full liquid phase reactor.

[0095] In one embodiment, the reasons for the runaway reaction include but are not limited to: the initial reaction temperature is too high, the initial reaction temperature is too low, too much material is added, too little material is added, too much catalyst is added, too little catalyst is added, cooling failure or external fire, feeding error, instrument air interruption, reaction pressure is too high, reaction pressure is too low, and internal leakage of heat exchange equipment.

[0096] Then, step S202, establish a runaway reaction. Determine the composition of the test sample used to test the runaway reaction according to the cause of the runaway reaction, perform a test reaction on the test sample to obtain a test product, and establish a macroscopic reaction equation of the runaway reaction according to the test product. During the test, a thermal safety test instrument is used to obtain the temperature rise rate change data of the reaction liquid in the reactor when it is out of control, and the reaction heat measurement value and macroscopic kinetic parameters of the runaway reaction including the reaction order n, activation energy Ea, and pre-exponential factor A are regressed. And establish a macroscopic reaction equation of the runaway reaction.

[0097] In one embodiment, the thermal safety testing instrument includes but is not limited to an accelerated reaction calorimeter (ARC), VSP2, phitec1, etc.

[0098] In one embodiment, the macroscopic reaction equation is established by a method of atomic balance of test gas phase products and liquid phase products.

[0099] Since some test products remain in the instrument and cannot be taken out, compensation is performed by atomic balance. Preferably, the liquid phase test products are compensated.

[0100] The atomic balance method, when performing atomic balance on the test gas phase product and liquid phase product, assumes that the mass of the solvent is balanced before and after the thermal safety test, and determines the total molar amount of each carbon-containing substance in the liquid phase product according to the principle of carbon atom balance. The missing sulfur (S), nitrogen (N), phosphorus (P) and other heteroatoms are preferentially supplemented with the missing heteroatoms and the corresponding molar amount of oxygen atoms (O) according to the heteroatom oxides with the lowest generation energy. The still missing oxygen atoms (O) and hydrogen atoms (H) are supplemented according to the generation of water molecules (H 2 O) first fill in one of the elements, and the missing oxygen atoms (O) or hydrogen atoms (H) are generated according to the oxygen molecule (O 2 ) and hydrogen molecules (H 2 ) is completed. The calculated value of the heat of reaction of the macroscopic reaction equation is calculated by the bond energy.

[0101] The atomic balance method ensures that the measured value of the reaction heat is consistent with the calculated value of the reaction heat by utilizing the simple reaction between molecules in the product when establishing the macroscopic reaction equation.

[0102] The simple reactions between molecules in the product include but are not limited to the dehydration reaction of organic matter and its reverse reaction, oxygen molecule (O 2 ) and hydrogen molecules (H 2 ) to generate water molecules (H 2 O) reaction and its reverse reaction.

[0103] Then in step S203, an equivalent simulation process is established. The states of all automatic control valves when the reactor has an abnormal operating condition are confirmed, and an equivalent simulation process of the reactor is established using process simulation software, and the reactor is divided into n micro-elements.

[0104] In one embodiment, the process simulation software includes but is not limited to Aspen, Hysys, and PROII.

[0105] Then, in step S204, a dynamic simulation of the out-of-control parameters is performed. Based on the out-of-control reaction established in step S202, the equivalent simulation process established in step S203 is used to simulate the out-of-control reaction condition of the reactor, and the change data of the reactor pressure over time and the change rate of the material density of each microelement of the continuously operated full liquid phase reactor are obtained. Data changes over time;

[0106] Step S205: Calculate the total discharge volume. The material density change rate at each position of the continuously operated full liquid phase reactor obtained in step S204 is The total release volume is calculated from the time-varying data.

[0107] In one of the embodiments, the states of all the automatic control valves, the automatic control valves that are not affected by the cause of the uncontrolled reaction, are always in their original positions.

[0108] In one embodiment, the total discharge amount and the maximum discharge amount of the continuously operated full liquid phase reactor under the uncontrolled reaction condition at different sampling times are calculated as follows:

[0109] The total discharge volume of the reactor at sampling time t is calculated as:

[0110]

[0111] The maximum discharge volume is calculated as:

[0112] W max =max(W t )

[0113] Where W t is the discharge volume of the full liquid phase reactor in continuous operation at a certain moment, n is the number of micro-elements into which the reactor is divided when simulating with process simulation software, V i is the volume of the corresponding infinitesimal element, is the density change rate of the corresponding microelement at a certain moment, The time when the reactor pressure first reaches the set pressure of the reactor safety relief device, W max The maximum discharge volume.

[0114] Preferably, when designing the reactor discharge system, the discharge aperture of the required safety discharge facility and various design parameters of the discharge post-treatment system are determined based on the calculated total discharge volume of the reactor, such as the throat diameter of the safety valve or the bursting aperture of the bursting disc, so that the maximum flow capacity of the discharge aperture is not less than the maximum discharge volume.

[0115] In the specific embodiment, the design pressure is 8MPaG, the design temperature is 300℃, the inner diameter is 3m, and the volume of the upper and lower heads is 10m 3 The calculation method of the release volume under the scenario of reaction runaway is described in detail using a continuously operated full liquid phase reactor. The catalyst height inside the reactor is 10m, the catalyst porosity is 0.5, and the catalyst bulk density is 1250kg / m 3, the specific heat capacity of the catalyst is 0.5 kJ / kg / K, the safety valve of the reactor is set at a pressure of 8 MPaG, and the main reaction in the reactor is that cumene hydroperoxide (CHP, raw material A) oxidizes propylene to produce propylene oxide.

[0116] like Figure 3 The flowchart of the method for calculating the discharge amount of a continuously operated full liquid phase reactor under the condition of out-of-control reaction is shown as the best embodiment of the present invention, including:

[0117] Step S301, determining the cause of the runaway reaction in the continuously operated full liquid phase reactor.

[0118] Step S302, establish a runaway reaction. Use a thermal safety test instrument to obtain the temperature rise rate change data when the reaction liquid in the reactor is out of control, and regress the reaction heat measurement value and macroscopic kinetic parameters of the runaway reaction including reaction order n, activation energy Ea, and pre-exponential factor A. And establish a macroscopic reaction equation of the runaway reaction;

[0119] Step S303, establishing an equivalent simulation process. Confirm the status of all automatic control valves when an abnormal operating condition occurs in the full liquid phase plug flow reactor, and use process simulation software to establish an equivalent simulation process of a continuously operated full liquid phase reactor;

[0120] Step S304, dynamic simulation of out-of-control parameters. Based on the out-of-control reaction established in step S302, the equivalent simulation process established in step S303 is used to simulate the out-of-control reaction condition of the continuously operated full liquid phase reactor, and the pressure change data of the continuously operated full liquid phase reactor over time and the material density change rate at each position of the continuously operated full liquid phase reactor are obtained. Data changes over time;

[0121] Step S305, total discharge volume calculation. The material density change rate at each position of the continuously operated full liquid phase reactor obtained in step D is: The total release volume is calculated from the time-varying data.

[0122] In step S301, the interruption of propylene feed is determined as the initial cause of the runaway reaction in the reactor. After the interruption of propylene feed, the 100°C cumene (solvent) solution containing 45 wt.% CHP instantly fills the adiabatic fixed bed reactor, and the reactor outlet pressure control loop adjusts the reactor outlet PV valve opening to gradually reduce, and the reactor outlet pressure is controlled at 4.7 MPaG. At this time, the reactor inlet pressure is 5 MPaG and the flow rate of imported CHP is 100 t / hr. CHP is catalytically decomposed in the adiabatic fixed bed reactor, causing the pressure and temperature of the adiabatic fixed bed reactor to increase.

[0123] In step S302, the runaway reaction kinetic parameters are regressed through the VSP2 test data; and the runaway reaction is established according to the analysis results of the gas phase sample and the liquid phase sample after the VSP2 test. Figure 4 The macroscopic reaction equation of the reaction is shown in the figure. The specific method of establishing the runaway reaction is as follows:

[0124] 1. Thermal safety test conditions:

[0125] The test sample composition is 27.5 g (0.229 mol) of solvent and 22.5 g (0.148 mol) of raw material A. The test system pressure before the thermal safety test is 1 barA and the gas phase volume is 60 ml.

[0126] 2. Test results:

[0127] 1) The measured value of the heat of reaction is 200 kJ / mol CHP; the residual pressure in the test container is 59.06 barA@20.11℃

[0128] 2) The composition analysis results of the test gas phase product and the test liquid phase product are as follows:

[0129] Gas phase product composition: O 2 0.1945 mol%CH 4 23.9365mol%, CO 68.0300mol%, H 2 7.8390mol%

[0130] Liquid product composition: solvent (isopropylbenzene) 69.1400wt.%, material B (α-methylstyrene) 16.1024wt.%, material C (dimethylbenzyl alcohol) 14.7074wt.%, H 2 O 0.0502wt.%

[0131]

[0132] 3. Establish the macroscopic reaction equation of runaway reaction:

[0133] Calculate the molar content of each element in the sample before thermal safety test:

[0134] According to the molar number and molecular formula of the solvent and raw material A before the thermal safety test, the molar content of each element in the sample before the thermal safety test is calculated as follows:

[0135] Total molar mass of carbon atoms = 0.229 mol × 9 + 0.148 mol × 9 = 3.393 mol

[0136] Total molar amount of hydrogen atoms = 0.229 mol × 12 + 0.148 mol × 12 = 4.524 mol

[0137] Total molar amount of oxygen atoms = 0.148 mol × 2 = 0.296 mol

[0138] 2) Assuming that the solvent is not consumed at all before and after the test, the mass of the liquid sample after the thermal safety test is calculated as:

[0139]

[0140] 3) Calculate the molar content of each component in the liquid sample after the thermal safety test:

[0141]

[0142] The molar amounts of the components in the liquid sample were calculated as follows: solvent 0.229 mol, material B 0.0543 mol, material C 0.0430 mol, H 2 O 0.00111mol.

[0143] 4) Calculate the molar content of each component in the gas phase sample after the thermal safety test:

[0144] According to the ideal state equation (PV = nRT), the total molar amount of the gas phase sample after the thermal safety test is calculated to be 0.142878 mol, and the molar content of each component in the gas phase sample is, 2 0.000278mol, CH 4 0.0342mol, CO 0.0972mol, H 2 0.0112mol.

[0145] 5) Calculate the total molar content of each element in the liquid and gas samples after the test:

[0146] Total molar mass of carbon atoms =

[0147] 0.229mol×9+0.0543mol×9+0.0430mol×9+0.0342mol+0.0972mol=3.068mol

[0148] Total molar amount of hydrogen atoms =

[0149] 0.229mol×12+0.0543mol×10+0.0430mol×12+0.00111mol×2+0.0342mol×4+0.0112mol×2=3.968mol

[0150] Total molar amount of oxygen atoms =

[0151] 0.0430mol+0.00111mol+0.000278mol×2+0.0972mol=0.142mol

[0152] 6) According to the carbon element balance, the carbon content in the liquid phase product is increased to achieve carbon element conservation before and after the thermal safety test:

[0153] The difference in the total molar amount of carbon element before and after the thermal safety test is 3.393mol-3.068mol=0.325mol. The molar amount of other carbon-containing components in the test liquid phase product except the solvent is increased in equal proportion, and the molar amount of the non-carbon-containing components in the test liquid phase product remains unchanged to achieve carbon conservation before and after the thermal safety test.

[0154]

[0155] Material C increased from 0.0430mol to

[0156]

[0157] 7) Recalculate the total molar content of each element in the liquid and gas samples after the conservation of carbon element:

[0158] Total molar mass of carbon atoms =

[0159] 0.229mol×9+0.0744mol×9+0.0590mol×9+0.0342mol+0.0972mol=3.393mol

[0160] Total molar amount of hydrogen atoms =

[0161] 0.229mol×12+0.0744mol×10+0.0590mol×12+0.00111mol×2+0.0342mol×4+0.0112mol×2=4.361mol

[0162] Total molar amount of oxygen atoms =

[0163] 0.0590mol+0.00111mol+0.000278mol×2+0.0972mol=0.158mol

[0164] 8) According to the balance of hydrogen and oxygen, increase the H 2 O content, and O in gas phase products 2 or H 2 The content of hydrogen and oxygen is achieved by:

[0165] Before the thermal safety test and after the carbon conservation, the difference in the total molar amount of hydrogen is 4.524mol-4.361mol=0.163mol; the difference in the total molar amount of oxygen is 0.296mol-0.158mol=0.138mol; 2 The O content increased to The gas phase product O 2 The content increased to

[0166] 9) After sorting, it can be found that every 0.148 mol of raw material A decomposes to produce 0.0744 mol of material B, 0.0590 mol of material C, and 0.0826 mol of H 2 O, 0.0285 mol O 2 , 0.0342 mol CH 4 , 0.0972 mol CO and 0.0112 mol H 2 Then the macroscopic reaction equation is 1:

[0167]

[0168] The calculated heat of reaction corresponding to the macroscopic reaction equation 1 is 171 kJ / mol CHP, which is less than the measured heat of reaction of 200 kJ / mol CHP. The macroscopic reaction equation 1 is modified to make 1 mol of H 2 and 0.5 mol O 2 The reaction produces 1 mol of H 2 O, and the macroscopic reaction equation 2 is obtained:

[0169]

[0170] The calculated heat of reaction corresponding to the macroscopic reaction equation 2 is 195 kJ / mol CHP, which is still less than the measured heat of reaction of 200 kJ / mol CHP. The macroscopic reaction equation 2 is further modified to make 1 mol of H 2 O reacts with 1 mol of material B to generate 1 mol of material C, and the macroscopic reaction equation 3 is obtained:

[0171]

[0172] The calculated value of the reaction heat corresponding to the reaction macroscopic reaction equation 3 is equal to the measured value of the reaction heat, and the reaction macroscopic reaction equation 3 is the macroscopic reaction equation of the runaway reaction finally established.

[0173] In step S303, Figure 5As shown, by using hysys software for dynamic simulation, the reactor upper head 51, the reactor lower head 52 and the catalyst bed 53 are divided into multiple microelements and modeled, and the controllers 56 and 57 are closed to keep the feed valve 54 (VLV-100) and the production valve 55 (VLV-101) always in normal operating openings, and establish an equivalent simulation process.

[0174] Next, enter step S304, combine the runaway reaction established in step S302 with the equivalent simulation process established using hysys in step S303, simulate the temperature, pressure, mass density, and mass density change rate of the adiabatic fixed bed reactor after the propylene feed is interrupted, and obtain the dynamic simulation value of the runaway parameter.

[0175] In step S305, the discharge amount of each microelement of the adiabatic fixed bed reactor at each moment is calculated, and finally the total discharge amount required by the adiabatic fixed bed reactor is obtained.

[0176] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for calculating the discharge volume under the condition of reactor reaction out of control, characterized in that: include: When the reactor reaction is out of control, determine the cause of the out-of-control reaction; Determine the composition of a test sample for testing a runaway reaction according to the cause of the runaway reaction, perform a test reaction on the test sample to obtain a test product, obtain a reaction heat measurement value and macroscopic kinetic parameters obtained in the test, and establish a macroscopic reaction equation of the runaway reaction according to the test product and the reaction heat measurement value; Establishing an equivalent simulation process for the reactor production process; The equivalent simulation process is used to simulate the runaway reaction condition of the reactor, and the macroscopic kinetic parameters and the macroscopic reaction equation of the runaway reaction are used to simulate the runaway reaction to obtain the change data of the reactor pressure over time and the change data of the change rate of the material parameters at each position of the reactor over time; The total discharge volume of the reactor is calculated based on the data of changes in the reactor pressure over time and the data of changes in the rate of change of material parameters at each position of the reactor over time.

2. The method for calculating the discharge amount under the reactor reaction out of control condition according to claim 1, characterized in that: The equivalent simulation process divides the reactor into a plurality of micro-elements, and the rate of change of material parameters at each position of the reactor is the rate of change of parameters of the materials included in each micro-element of the reactor.

3. The method for calculating the discharge amount under the reactor out-of-control condition according to claim 2, characterized in that: The method of calculating the total discharge volume of the reactor according to the change data of the reactor pressure over time and the change data of the change rate of the material parameters at each position of the reactor over time specifically includes: The total discharge volume and the maximum discharge volume of the reactor at different sampling times are calculated based on the data of changes in the reactor pressure over time and the data of changes in the rate of change of material parameters at each position of the reactor over time.

4. The method for calculating the discharge amount under the reactor out-of-control condition according to claim 3, characterized in that: The parameter change rate is the density change rate, and the total discharge amount and the maximum discharge amount of the reactor at different sampling times are calculated according to the change data of the reactor pressure over time and the change data of the material parameter change rate at each position of the reactor over time, specifically including: The total discharge volume of the reactor at sampling time t is calculated as: The maximum discharge volume is calculated as: W max =max(W t ) Where: W t is the total discharge of the reactor at sampling time t, n is the number of micro-elements divided into the reactor, V i is the volume of the ith infinitesimal element, is the density change rate of the ith element at sampling time t, The time when the reactor pressure first reaches the set pressure of the reactor safety relief device, W max The maximum discharge volume.

5. The method for calculating the discharge amount under the reactor out-of-control condition according to claim 1, characterized in that: The macroscopic reaction equation of the runaway reaction is established according to the test product and the reaction heat measurement value, specifically comprising: Compensating the test product according to the difference between the molar amount of the substance contained in the test sample and the molar amount of the substance contained in the test product; Generate an initial macroscopic reaction equation of the runaway reaction according to the compensated test product and the test sample; The calculated value of the reaction heat of the initial macroscopic reaction equation is determined by bond energy calculation. The initial macroscopic reaction equation is corrected according to the calculated value of the reaction heat of the initial macroscopic reaction equation and the measured value of the reaction heat. The corrected macroscopic reaction equation is used as the macroscopic reaction equation of the runaway reaction.

6. The method for calculating the discharge amount under the reactor out-of-control condition according to claim 5, characterized in that: The method of compensating the test product according to the difference between the molar amount of the substance contained in the test sample and the molar amount of the substance contained in the test product specifically includes: Atomic balance compensation is performed on each element contained in the test product, and the atomic balance compensation is: Calculate the molar difference between the molar amount of atoms of the element in the test sample and the molar amount of atoms of the element in the test product; The compensation amount of each type of substance containing atoms of the element in the test product is calculated according to the molar weight difference, and the substances containing atoms of the element in the test product are compensated using the compensation amount.

7. The method for calculating the discharge amount under the reactor reaction out of control condition according to claim 6, characterized in that: The test sample contains carbon, oxygen, hydrogen, and / or other miscellaneous elements, and performing atomic balance compensation on each element contained in the test product specifically includes: A carbon element compensation step, if the test product contains carbon element, then the carbon element atomic balance compensation is performed on the substance containing carbon element in the test sample, and then it is determined whether the test product contains impurity elements. If the test product contains impurity elements, then the impurity element compensation step is performed on the test product after the carbon element atomic balance compensation is performed, otherwise, the hydrogen and oxygen compensation step is performed on the test product after the carbon element atomic balance compensation is performed; The impurity element compensation step is to perform atomic balance compensation of impurity elements on the substance containing impurity elements in the test product, and then determine whether the test product after the atomic balance compensation of impurity elements is still missing oxygen atoms or hydrogen atoms compared with the test sample. If missing, perform the hydrogen-oxygen compensation step, otherwise end; A hydrogen-oxygen compensation step is performed on the water molecules in the test product, and the atomic balance compensation of the oxygen element is performed on the test product for which the atomic balance compensation of the hydrogen element is performed, or the atomic balance compensation of the oxygen element is performed on the water molecules in the test product, and the atomic balance compensation of the hydrogen element is performed on the test product for which the atomic balance compensation of the oxygen element is performed.

8. The method for calculating the discharge volume under the reactor out-of-control condition according to claim 5, characterized in that: The method of correcting the initial macroscopic reaction equation according to the calculated reaction heat value of the initial macroscopic reaction equation and the measured reaction heat value, and using the corrected macroscopic reaction equation as the macroscopic reaction equation of the runaway reaction, specifically includes: Selecting one possible reaction as a selected reaction from the possible reactions occurring between molecules in the product of the initial macro-reaction equation, and modifying the initial macro-reaction equation successively, wherein in each modification, in the product of the macro-reaction equation, the reactants of the selected reaction are replaced by the products of the product; After each correction of the initial macroscopic reaction equation, the calculated value of the reaction heat of the corrected macroscopic reaction equation is calculated. If the difference between the calculated value of the reaction heat of the macroscopic reaction equation after the reaction and the measured value of the reaction heat is within a preset range, the macroscopic reaction equation after the reaction is selected as the macroscopic reaction equation of the runaway reaction. Otherwise, continue to rotate the next possible reaction and correct the corrected macroscopic reaction equation again.

9. The method for calculating the discharge amount under the reactor out-of-control condition according to claim 8, characterized in that: The possible reactions include: a dehydration reaction of an organic substance, a reverse reaction of the dehydration reaction of an organic substance, a reaction of oxygen molecules and hydrogen molecules generating water molecules, and / or a reaction of water molecules decomposing into oxygen molecules and hydrogen molecules.

10. The method for calculating the discharge volume under the reactor out-of-control condition according to claim 1, characterized in that: The establishment of an equivalent simulation process for the reactor production process specifically includes: Obtain the status of all automatic control valves when the reactor reaction is out of control; An equivalent simulation process for the reactor production process is established to keep the automatic control valves other than those affected by the out-of-control cause in the state when the reactor reaction is out of control.

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