Isothermal isobaric flash calculation method and device, electronic equipment and storage medium

Abstract

The invention discloses an isothermal and isobaric flash calculation method and device, electronic equipment and a storage medium, and specifically comprises the following steps: acquiring a plurality of system parameters of a non-ideal system, and estimating a phase equilibrium constant of the non-ideal system to obtain an initial value of the phase equilibrium constant; based on a gas-liquid two-phase flash evaporation model, the initial value and a plurality of system parameters, analyzing whether the fed material has liquid phase stability or not; if the feed does not have the liquid phase stability, analyzing whether the feed has the gas phase stability or not; and if the feed does not have the gas phase stability, carrying out gas-liquid two-phase flash evaporation calculation on the feed, and obtaining and outputting a calculation result. Compared with the prior art, the method can enable the calculation result to be closer to the actual condition.

Description

Technical Field

[0001] The present application relates to the field of chemical production technology, and more specifically, to an isothermal and isobaric flash evaporation calculation method, device, electronic equipment and storage medium. Background Art

[0002] The flash phenomenon uses the principle of the boiling point of substances. At higher pressures, the boiling point of liquids is higher and more heat is required to reach the boiling point. When the pressure is reduced, part of the sensible heat is released, and this energy is absorbed in the form of latent heat, causing part of the liquid to quickly convert into steam. Isothermal flash evaporation refers to the phenomenon that saturated liquid is partially converted into steam when the pressure is reduced at a certain temperature. Specifically, when a saturated liquid at high pressure enters a container at a lower pressure, part of the liquid will be converted into steam due to the sudden decrease in pressure. This process is called flash evaporation.

[0003] In chemical production systems, the isothermal and isobaric flash calculation method is required to determine the composition and quantity of the gas-liquid phases in the system after the mixture is separated at a certain temperature and pressure. However, in non-ideal systems where the real solution deviates greatly from the ideal solution model, the infinite dilution activity coefficient of the components in the system is particularly large or small, which makes the liquid phase fugacity coefficient vary greatly during the calculation process, making it difficult to converge the calculation results, making it difficult to obtain accurate calculation results, and thus making it impossible for the production control system to implement stable control of the chemical production system. Summary of the invention

[0004] In view of this, the present application provides an isothermal and isobaric flash calculation method, device, electronic device and storage medium for performing isothermal and isobaric flash calculation on non-ideal embodiments to obtain accurate calculation results, so that the production control system can implement stable control of the chemical production process based on the calculation results.

[0005] In order to achieve the above objectives, the proposed solution is as follows:

[0006] An isothermal and isobaric flash evaporation calculation method is applied to electronic equipment and is used to calculate the composition and quantity of gas-liquid two-phase substances after phase separation of a mixture in a non-ideal system. The isothermal and isobaric flash evaporation calculation method comprises the following steps:

[0007] Acquiring a plurality of system parameters of the non-ideal system, wherein the plurality of parameters include the composition of the feed, and also include the system temperature and system pressure of the non-ideal system;

[0008] estimating the phase equilibrium constant of the non-ideal system to obtain an initial value of the phase equilibrium constant;

[0009] Based on the gas-liquid two-phase flash model, the initial value and the multiple system parameters, analyzing whether the feed of the non-ideal system has liquid phase stability, outputting the analysis result if it has liquid phase stability, and correcting the initial value to obtain a first corrected value of the phase equilibrium parameter;

[0010] If the feed does not have liquid phase stability, then based on the gas-liquid two-phase flash model, the first correction value and the plurality of system parameters, whether the feed has gas phase stability is analyzed and processed; if the feed has gas phase stability, the analysis result is output, and the first correction value is corrected to obtain a second correction value of the phase equilibrium parameter;

[0011] If the feed does not have gas phase stability, a gas-liquid two-phase flash calculation is performed on the feed based on the gas-liquid two-phase flash model, the second correction value and the plurality of system parameters to obtain and output a calculation result.

[0012] Optionally, the gas-liquid two-phase flash evaporation model includes a mass conservation equation, a phase equilibrium equation, a composition normalization equation and a heat conservation equation.

[0013] Optionally, the heat conservation equation is the Rachford-Rice equation.

[0014] Optionally, the method of analyzing whether the feed of the non-ideal system has liquid phase stability based on the gas-liquid two-phase flash model, the initial value and the multiple system parameters, outputting the analysis result if the feed has liquid phase stability, and correcting the initial value to obtain the first corrected value of the phase equilibrium parameter comprises the steps of:

[0015] calculating a first liquid phase fugacity coefficient based on the composition, the system temperature, and the system pressure;

[0016] calculating a virtual gas phase composition based on an initial value of the phase equilibrium constant;

[0017] Calculating a sum of virtual gas phase compositions based on the virtual gas phase compositions;

[0018] calculating a normalized gas phase composition based on the virtual gas phase composition and the sum of the virtual gas phase composition;

[0019] calculating a first gas phase fugacity coefficient based on the normalized gas phase composition, the system temperature, and the system pressure;

[0020] updating the initial value of the phase equilibrium constant according to the first liquid phase fugacity coefficient and the first gas phase fugacity coefficient;

[0021] Determining whether the initial value converges, if not, returning to the step of calculating the virtual gas phase composition based on the initial value of the phase equilibrium constant, if converged, executing subsequent operations, and using the final initial value as the first correction value;

[0022] The feed is judged according to the sum of the virtual gas phase compositions. If the sum of the virtual gas phase compositions is less than or equal to zero, the feed has liquid phase stability; otherwise, the feed does not have liquid phase stability.

[0023] Optionally, if the feed does not have liquid phase stability, then based on the gas-liquid two-phase flash model, the first correction value and the multiple system parameters, analyzing whether the feed has gas phase stability, if so, outputting the analysis result, and correcting the first correction value to obtain a second correction value of the phase equilibrium parameter, comprising the steps of:

[0024] calculating a second gas phase fugacity coefficient based on the composition, the system temperature, and the system pressure;

[0025] Calculating a virtual liquid phase composition based on a first corrected value of the phase equilibrium constant;

[0026] Calculating a sum of virtual liquid phase compositions based on the virtual liquid phase compositions;

[0027] calculating a normalized liquid phase composition based on the virtual liquid phase composition and the sum of the virtual liquid phase composition;

[0028] calculating a second liquid phase fugacity coefficient based on the normalized liquid phase composition, the system temperature, and the system pressure;

[0029] updating a first correction value of the phase equilibrium constant according to the second liquid phase fugacity coefficient and the second gas phase fugacity coefficient;

[0030] Determine whether the first correction value converges, and if not, return to the step of calculating the virtual liquid phase composition based on the first correction value of the phase equilibrium constant; if converged, perform subsequent operations, and use the final first correction value as the second correction value;

[0031] The feed is judged according to the sum of the virtual liquid phase compositions. If the sum of the virtual liquid phase compositions is less than or equal to zero, the feed has gas phase stability; otherwise, the feed does not have gas phase stability.

[0032] Optionally, if the feed does not have gas phase stability, performing gas-liquid two-phase flash calculation on the feed based on the second correction value of the gas-liquid two-phase flash model and the multiple system parameters to obtain and output the calculation result comprises the steps of:

[0033] determining whether the second correction value can make the flash problem true;

[0034] If the flash evaporation problem cannot be established, adjusting the second correction value;

[0035] If the flash evaporation problem is established, the second correction value is iteratively processed based on the heat conservation equation to obtain an iterative reference value;

[0036] Divide the range between the second correction value and the iteration reference value into a plurality of value segments, and sequentially perform the calculation based on the constraint value corresponding to each of the value segments until the constraint value converges;

[0037] When the constraint value converges, the calculation result is output.

[0038] Optionally, if the flash evaporation problem cannot be established, adjusting the second correction value comprises the steps of:

[0039] Calculating a sum of virtual gas phase compositions and a sum of virtual liquid phase compositions of the feed based on the second correction value;

[0040] The second correction value is adjusted based on the sum of the virtual gas phase composition and the sum of the virtual liquid phase composition.

[0041] An isothermal and isobaric flash evaporation calculation device is applied to electronic equipment and is used to calculate the composition and quantity of gas-liquid two-phase substances after phase separation of a mixture in a non-ideal system. The isothermal and isobaric flash evaporation calculation device comprises:

[0042] A parameter acquisition module is configured to acquire a plurality of system parameters of the non-ideal system, wherein the plurality of parameters include the composition of the feed, and also include a system temperature and a system pressure of the non-ideal system;

[0043] A constant estimation module is configured to estimate the phase equilibrium constant of the non-ideal system to obtain an initial value of the phase equilibrium constant;

[0044] a liquid phase stability testing module configured to analyze whether the feed of the non-ideal system has liquid phase stability based on the gas-liquid two-phase flash model, the initial value and the multiple system parameters, output the analysis result if it has liquid phase stability, and correct the initial value to obtain a first corrected value of the phase equilibrium parameter;

[0045] a gas phase stability testing module configured to analyze whether the feed has gas phase stability based on the gas-liquid two-phase flash model, the first correction value and the plurality of system parameters if the feed does not have liquid phase stability, output an analysis result if the feed has gas phase stability, and correct the first correction value to obtain a second correction value of the phase equilibrium parameter;

[0046] The flash calculation execution module is configured to perform gas-liquid two-phase flash calculation on the feed based on the gas-liquid two-phase flash model, the second correction value and the plurality of system parameters if the feed does not have gas phase stability, and obtain and output a calculation result.

[0047] An electronic device, comprising at least one processor and a memory connected to the processor, wherein:

[0048] The memory is used to store computer programs or instructions;

[0049] The processor is used to execute the computer program or instruction so that the electronic device implements the isothermal and isobaric flash evaporation calculation method as described above.

[0050] A computer-readable storage medium is applied to an electronic device, wherein the storage medium carries one or more computer programs, and the one or more computer programs can be executed by the electronic device, so that the electronic device implements the isothermal and isobaric flash evaporation calculation method as described above.

[0051] It can be seen from the above technical scheme that the present application discloses an isothermal and isobaric flash calculation method, device, electronic device and storage medium. The method and device are applied to electronic devices, specifically to obtain multiple system parameters of a non-ideal system, estimate the phase equilibrium constant of the non-ideal system, and obtain the initial value of the phase equilibrium constant; based on the gas-liquid two-phase flash evaporation model, the initial value and multiple system parameters, analyze and process whether the feed of the non-ideal system has liquid phase stability, and correct the initial value to obtain a first corrected value of the phase equilibrium parameter; if the feed does not have liquid phase stability, then based on the gas-liquid two-phase flash evaporation model, the first corrected value and multiple system parameters, analyze and process whether the feed has gas phase stability, and correct the first corrected value to obtain a second corrected value of the phase equilibrium parameter; if the feed does not have gas phase stability, then based on the gas-liquid two-phase flash evaporation model, the second corrected value and multiple system parameters, perform gas-liquid two-phase flash calculation on the feed, and obtain and output the calculation result. Compared with the prior art, the present application uses a strict thermodynamic model to determine the phase state, so that the calculation results can be closer to the actual situation, and the production control system can implement stable control of the chemical production process based on the calculation results.

[0052] In addition, compared with the prior art, the present application uses the batch test method and the optimal criterion in the gas phase stability test and the gas-liquid two-phase flash calculation, which can effectively avoid the volatility of the iterative process and improve the robustness of the algorithm. And the method of adjusting the K value can ensure that the Rachford-Rice equation has a solution when the system is confirmed to be gas-liquid two-phase, and ensure that it can be iterated. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 A flow chart of an isothermal and isobaric flash evaporation calculation method according to an embodiment of the present application;

[0055] Figure 2 A flow chart of the liquid phase testing process of an embodiment of the present application;

[0056] Figure 3 A flow chart of the gas phase testing process of an embodiment of the present application;

[0057] Figure 4 A flow chart of the gas-liquid two-phase flash evaporation calculation process of an embodiment of the present application;

[0058] Figure 5 A block diagram of an isothermal and isobaric flash evaporation calculation device according to an embodiment of the present application;

[0059] Figure 6 A block diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0061] This application implements flash calculation based on the following gas-liquid two-phase flash model, which controls the mass conservation equation, phase equilibrium equation, composition normalization equation and heat conservation equation. The details are as follows:

[0062] The mass conservation equation is:

[0063] F i=Vy i +Lx i

[0064] Where F is the molar flow rate of the feed; i is the molar composition of feed composition i; V is the molar flow rate of gas phase; y i is the molar composition of the gas phase i; L is the molar flow rate of the liquid phase; x i is the molar composition of liquid phase composition i.

[0065] The phase equilibrium equation is:

[0066] y i =K i x i

[0067] In the formula, K i is the phase equilibrium constant of composition i.

[0068] The composition normalization equation is:

[0069] ∑y i =1

[0070] ∑x i =1

[0071] The heat conservation equation is:

[0072] FH F +Q=VH V +LH L

[0073] In the formula, H F is the molar enthalpy of the feed; Q is the additional heat flow; H V is the molar enthalpy of the gas phase; H L is the molar enthalpy of the liquid phase.

[0074] From the mass conservation equation, phase equilibrium equation and composition normalization equation, we can get

[0075]

[0076] Where ψ is the gas phase fraction ψ = V / F.

[0077] Subtracting the above two equations gives the Rachford-Rice equation:

[0078]

[0079] Since the Rachford-Rice equation has good convergence, the equation is chosen to be iterated to solve the flash model. Based on the above model, the following specific implementation is proposed.

[0080] Figure 1 This is a flow chart of an isothermal and isobaric flash evaporation calculation method according to an embodiment of the present application.

[0081] like Figure 1 As shown, the isothermal and isobaric flash calculation method provided in this embodiment is applied to electronic equipment for flash calculation of non-ideal systems. The electronic equipment can be understood as a computer, server, cloud platform or controller or embedded device of a chemical production system with data calculation and information processing capabilities. The calculation method includes the following specific steps:

[0082] S1. Obtain multiple system parameters of a non-ideal system.

[0083] The system parameters include, but are not limited to, the composition of the feed to the system, and the system temperature and system pressure of the system.

[0084] S2. Estimate the phase equilibrium parameter K of the non-ideal system.

[0085] The phase equilibrium parameter K of the non-ideal system is calculated through the preset steps. There are two methods to estimate the initial value of the phase equilibrium constant K:

[0086] ①Wilson correlation;

[0087] K i =exp(5.373*(1+ω i )*(1-1 / Tr i ) / Pr i

[0088] In the formula, ω i is the eccentricity factor of component i; Tr i is the comparative temperature of composition i; Pr i is the comparative pressure of component i.

[0089] ② Assuming an ideal gas and ideal solution model, calculate the K value using the saturated vapor pressure method provided by the process simulation software.

[0090] K i =P i s / P

[0091] Where P i s is the saturated vapor pressure of composition i; P is the system pressure.

[0092] The method adopted by the present invention is to give priority to method ①, and if method ① cannot be used due to missing parameters, method ② is used.

[0093] S3. Determine whether the feed of the non-ideal system has liquid phase stability.

[0094] That is, based on the gas-liquid two-phase flash model, the initial value of the phase equilibrium constant and the above-mentioned multiple system parameters, whether the feed of the non-ideal system has liquid phase stability is analyzed and processed. If it has liquid phase stability, the analysis result is output, and the initial value of the phase equilibrium constant is corrected to obtain the first corrected value of the phase equilibrium parameter. The specific process is as follows Figure 2 As shown:

[0095] 1. Composition of feed i , system temperature T, system pressure P, and calculate to obtain the first liquid phase fugacity coefficient

[0096] 2. Calculate the virtual gas phase composition Y i =z i K i ;

[0097] 3. Calculate the sum of virtual gas phase composition SumY = ∑Y i ;

[0098] 4. Calculate the normalized gas phase composition y i =Y i / SumY;

[0099] 5. Normalized gas phase composition y i , system temperature T, system pressure, and calculate to obtain the first gas phase fugacity coefficient

[0100] 6. Update phase equilibrium constants

[0101] 7. Repeat steps 2 to 6 until the initial values ​​of the above phase equilibrium parameters converge.

[0102] During the liquid phase stability test, when the above phase equilibrium parameters converge, if SumY<=0, the feed is liquid phase and the virtual gas phase composition is output; if SumY>0, it indicates that there is no liquid phase stability, and the next step of gas phase stability detection is carried out.

[0103] S4. Determine whether the feed of the non-ideal system has gas phase stability.

[0104] If the feed does not have liquid phase stability, then based on the gas-liquid two-phase flash model, the first correction value and multiple system parameters, whether the feed has gas phase stability is analyzed and processed. If it has gas phase stability, the analysis result is output, and the first correction value is corrected to obtain a second correction value of the phase equilibrium parameter, such as Figure 3 shown.

[0105] 1. Composed of feed i , system temperature T, system pressure P, and calculate to obtain the second gas phase fugacity coefficient

[0106] 2. Calculate the virtual liquid phase composition X i =z i / K i ;

[0107] 3. Calculate the sum of virtual liquid phase composition SumX = ∑X i ;

[0108] 4. Calculate the normalized liquid phase composition x i =X i / SumX;

[0109] 5. Normalized liquid phase composition x i , system temperature T, system pressure P, and calculate to obtain the second liquid phase fugacity coefficient

[0110] 6. Calculate the reference value of the next round of phase equilibrium constant

[0111] 7. Use the batch test method to i to The average score is N test Segment (optional 2 to 20), get

[0112] 8. By Execute steps 2 to 6 to get the K value for the next round.

[0113] 9. Calculate and compare Find the one that makes The smallest set of K values ​​K i min As the K value of the next round, As the next round

[0114] 10. Repeat steps 7 to 9 until the first correction value of the above phase equilibrium parameter converges.

[0115] Gas phase stability test process When the above first correction value converges, if SumX<=0, the feed is gas phase, and the virtual liquid phase composition is output; if SumX>0, it indicates that the feed is not pure gas phase, and the next step of gas-liquid two-phase flash calculation is carried out.

[0116] S5. Perform gas-liquid two-phase flash evaporation calculation on the feed.

[0117] If the feed does not have gas phase stability, the feed is subjected to gas-liquid two-phase flash calculation based on the second correction value of the gas-liquid two-phase flash model and multiple system parameters, and the calculation results are obtained and output, such as Figure 4 shown.

[0118] 1. The K value output by the gas phase stability test module is input into the gas-liquid two-phase flash module as the initial value;

[0119] 2. Determine whether the K value can make the flash evaporation problem work. If not, adjust the K value. The specific method is as follows:

[0120] 2-1. Calculate SumX=∑z from K value i / K i SumY = ∑z i *K i If both SumX and SumY are greater than 1, no adjustment is required and go directly to step (3); otherwise, go to step (2.2);

[0121] 2-2. If SumX<1, then coefficient C=SumX 0.9 *SumY -0.1 ; If SumY<1, then coefficient C=SumX 0.1 *SumY -0.9 ;

[0122] 2-3. Adjust K value, K i =K i *C;

[0123] 3. Solve the Rachford-Rice equation by trial position method to obtain the next iteration reference value

[0124] 4. Use the batch test method to i to Divide into Ntest ​​segments (optional 2 to 20), and get

[0125] 5. By Execute steps (2) and (3) to obtain the K value for the next round.

[0126] 6. Calculate and compare Ntest Find the one that makes The smallest set of K values As the K value of the next round, As the next round

[0127] 7. Repeat steps 5 and 6 until the second correction value of the phase equilibrium parameter converges, at which time the gas phase composition, liquid phase composition, and gas phase fraction are output as calculation results.

[0128] It can be seen from the above technical scheme that this embodiment provides an isothermal and isobaric flash calculation method, which is applied to electronic equipment, specifically obtaining multiple system parameters of a non-ideal system, estimating the phase equilibrium constant of the non-ideal system, and obtaining the initial value of the phase equilibrium constant; based on the gas-liquid two-phase flash model, the initial value and multiple system parameters, whether the feed of the non-ideal system has liquid phase stability is analyzed and processed, and the initial value is corrected to obtain the first corrected value of the phase equilibrium parameter; if the feed does not have liquid phase stability, then based on the gas-liquid two-phase flash model, the first corrected value and multiple system parameters, whether the feed has gas phase stability is analyzed and processed, and the first corrected value is corrected to obtain the second corrected value of the phase equilibrium parameter; if the feed does not have gas phase stability, then based on the gas-liquid two-phase flash model, the second corrected value and multiple system parameters, the feed is calculated for gas-liquid two-phase flash, and the calculation result is obtained and output. Compared with the prior art, the present application uses a strict thermodynamic model to judge the phase state, so that the calculation result can be closer to the actual situation, and then the production control system implements stable control of the chemical production process based on the calculation result.

[0129] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present disclosure. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some implementations as replacements, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0130] Although operations are depicted in a particular order, this should not be understood as requiring that the operations be performed in the particular order shown or in a sequential order.Multitasking and parallel processing may be advantageous under certain circumstances.

[0131] It should be understood that the various steps described in the method embodiments of the present disclosure may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present disclosure is not limited in this respect.

[0132] Computer program code for performing the operations of the present disclosure may be written in one or more programming languages ​​or a combination thereof, including, but not limited to, object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as C or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer.

[0133] Figure 5 This is a block diagram of an isothermal and isobaric flash evaporation calculation device according to an embodiment of the present application.

[0134] like Figure 5 As shown, the isothermal and isobaric flash calculation device provided in this embodiment is applied to an electronic device for performing flash calculation on a non-ideal system. The electronic device can be understood as a computer, server, cloud platform or controller or embedded device of a chemical production system with data calculation and information processing capabilities. The calculation device includes a parameter acquisition module 10, a constant estimation module 20, a liquid phase stability test module 30, a gas phase stability test module 40 and a flash calculation execution module 50.

[0135] The parameter acquisition module is used to obtain multiple system parameters of a non-ideal system.

[0136] The system parameters include, but are not limited to, the composition of the feed to the system, and the system temperature and system pressure of the system.

[0137] The constant estimation module is used to estimate the phase equilibrium parameter K of non-ideal systems.

[0138] The phase equilibrium parameter K of the non-ideal system is calculated through the preset steps. There are two methods to estimate the initial value of the phase equilibrium constant K:

[0139] ①Wilson correlation;

[0140] K i =exp(5.373*(1+ω i )*(1-1 / Tr i ) / Pr i

[0141] In the formula, ω i is the eccentricity factor of component i; Tr i is the comparative temperature of composition i; Pri is the comparative pressure of component i.

[0142] ② Assuming an ideal gas and ideal solution model, calculate the K value using the saturated vapor pressure method provided by the process simulation software.

[0143] K i =P i s / P

[0144] Where P i s is the saturated vapor pressure of composition i; P is the system pressure.

[0145] The method adopted by the present invention is to give priority to method ①, and if method ① cannot be used due to missing parameters, method ② is used.

[0146] The liquid phase stability test module is used to determine whether the feed of a non-ideal system has liquid phase stability.

[0147] That is, based on the gas-liquid two-phase flash model, the initial value of the phase equilibrium constant and the above-mentioned multiple system parameters, whether the feed of the non-ideal system has liquid phase stability is analyzed and processed. If it has liquid phase stability, the analysis result is output, and the initial value of the phase equilibrium constant is corrected to obtain the first corrected value of the phase equilibrium parameter. The specific process is as follows Figure 2 As shown:

[0148] 1. Composition of feed i , system temperature T, system pressure P, and calculate to obtain the first liquid phase fugacity coefficient

[0149] 2. Calculate the virtual gas phase composition Y i =z i K i ;

[0150] 3. Calculate the sum of virtual gas phase composition SumY = ∑Y i ;

[0151] 4. Calculate the normalized gas phase composition y i =Y i / SumY;

[0152] 5. Normalized gas phase composition y i , system temperature T, system pressure, and calculate to obtain the first gas phase fugacity coefficient

[0153] 6. Update phase equilibrium constants

[0154] 7. Repeat steps 2 to 6 until the initial values ​​of the above phase equilibrium parameters converge.

[0155] During the liquid phase stability test, when the above phase equilibrium parameters converge, if SumY<=0, the feed is liquid phase and the virtual gas phase composition is output; if SumY>0, it indicates that there is no liquid phase stability, and the next step of gas phase stability detection is carried out.

[0156] The gas phase stability test module is used to determine whether the feed of a non-ideal system has gas phase stability.

[0157] If the feed does not have liquid phase stability, then based on the gas-liquid two-phase flash model, the first correction value and multiple system parameters, whether the feed has gas phase stability is analyzed and processed. If it has gas phase stability, the analysis result is output, and the first correction value is corrected to obtain a second correction value of the phase equilibrium parameter, such as Figure 3 shown.

[0158] 1. Composed of feed i , system temperature T, system pressure P, and calculate to obtain the second gas phase fugacity coefficient

[0159] 2. Calculate the virtual liquid phase composition X i =z i / K i ;

[0160] 3. Calculate the sum of virtual liquid phase composition SumX = ∑X i ;

[0161] 4. Calculate the normalized liquid phase composition x i =X i / SumX;

[0162] 5. Normalized liquid phase composition x i , system temperature T, system pressure P, and calculate to obtain the second liquid phase fugacity coefficient

[0163] 6. Calculate the reference value of the next round of phase equilibrium constant

[0164] 7. Use the batch test method to i to The average score is N test Segment (optional 2 to 20), get

[0165] 8. By Execute steps 2 to 6 to get the K value for the next round.

[0166] 9. Calculate and compare Find the one that makes The smallest set of K values As the K value of the next round, As the next round

[0167] 10. Repeat steps 7 to 9 until the first correction value of the above phase equilibrium parameter converges.

[0168] Gas phase stability test process When the above first correction value converges, if SumX<=0, the feed is gas phase, and the virtual liquid phase composition is output; if SumX>0, it indicates that the feed is not pure gas phase, and the next step of gas-liquid two-phase flash calculation is carried out.

[0169] The flash calculation execution module is used to perform gas-liquid two-phase flash calculation on the feed.

[0170] If the feed does not have gas phase stability, the feed is subjected to gas-liquid two-phase flash calculation based on the second correction value of the gas-liquid two-phase flash model and multiple system parameters, and the calculation results are obtained and output, such as Figure 4 shown.

[0171] 1. The K value output by the gas phase stability test module is input into the gas-liquid two-phase flash module as the initial value; 2. Determine whether the K value can make the flash problem work. If not, adjust the K value. The specific method is as follows:

[0172] 2-1. Calculate SumX=Σz from K value i / K i SumY = ∑z i *K i If both SumX and SumY are greater than 1, no adjustment is required and go directly to step (3); otherwise, go to step (2.2);

[0173] 2-2. If SumX<1, then coefficient C=SumX 0.9 *SumY -0.1 ; If SumY<1, then coefficient C=SumX 0.1 *SumY -0.9 ;

[0174] 2-3. Adjust K value, K i =K i *C;

[0175] 3. Solve the Rachford-Rice equation by trial position method to obtain the next iteration reference value

[0176] 4. Use the batch test method to i to Divide into Ntest ​​segments (optional 2 to 20), and get

[0177] 5. By Execute steps (2) and (3) to obtain the K value for the next round.

[0178] 6. Calculate and compare Ntest Find the one that makes The smallest set of K values As the K value of the next round, As the next round

[0179] 7. Repeat steps 5 and 6 until the second correction value of the phase equilibrium parameter converges, at which time the gas phase composition, liquid phase composition, and gas phase fraction are output as calculation results.

[0180] It can be seen from the above technical scheme that this embodiment provides an isothermal and isobaric flash calculation device, which is applied to electronic equipment, specifically obtaining multiple system parameters of a non-ideal system, estimating the phase equilibrium constant of the non-ideal system, and obtaining the initial value of the phase equilibrium constant; based on the gas-liquid two-phase flash model, the initial value and multiple system parameters, whether the feed of the non-ideal system has liquid phase stability is analyzed and processed, and the initial value is corrected to obtain the first corrected value of the phase equilibrium parameter; if the feed does not have liquid phase stability, then based on the gas-liquid two-phase flash model, the first corrected value and multiple system parameters, whether the feed has gas phase stability is analyzed and processed, and the first corrected value is corrected to obtain the second corrected value of the phase equilibrium parameter; if the feed does not have gas phase stability, then based on the gas-liquid two-phase flash model, the second corrected value and multiple system parameters, the feed is calculated for gas-liquid two-phase flash, and the calculation result is obtained and output. Compared with the prior art, the present application uses a strict thermodynamic model to judge the phase state, so that the calculation result can be closer to the actual situation, and then the production control system implements stable control of the chemical production process based on the calculation result.

[0181] The units involved in the embodiments described in the present disclosure may be implemented by software or hardware. The name of a unit does not limit the unit itself in some cases. For example, the first acquisition unit may also be described as a "unit for acquiring at least two Internet Protocol addresses".

[0182] The functions described above herein may be performed at least in part by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), and the like.

[0183] Figure 6 A block diagram of an electronic device according to an embodiment of the present application.

[0184] Reference below Figure 6 , which shows a schematic diagram of the structure of an electronic device suitable for implementing the embodiments of the present disclosure. The terminal device in the embodiments of the present disclosure may include, but is not limited to, mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. The electronic device is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present disclosure.

[0185] The electronic device may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 601, which can perform various appropriate actions and processes according to a program stored in a read-only memory ROM 602 or a program loaded from an input device 606 into a random access memory RAM 603. In the RAM, various programs and data required for the operation of the electronic device are also stored. The processing device, ROM, and RAM are connected to each other via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0186] Typically, the following devices may be connected to the I / O interface: input devices including, for example, a touch screen, a touchpad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; output devices 607 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 608 including, for example, a magnetic tape, a hard disk, etc.; and communication devices 609. The communication device 609 may allow the electronic device to communicate with other devices wirelessly or by wire to exchange data. Although the figure shows an electronic device with various devices, it should be understood that it is not required to implement or have all the devices shown. More or fewer devices may be implemented or have alternatively.

[0187] The present application also provides an embodiment of a computer-readable storage medium.

[0188] The computer-readable storage medium is applied to an electronic device and carries one or more computer programs. When the one or more computer programs are executed by the electronic device, the electronic device estimates the phase equilibrium constant of the non-ideal system to obtain multiple system parameters of the non-ideal system and obtains an initial value of the phase equilibrium constant; based on the gas-liquid two-phase flash evaporation model, the initial value and multiple system parameters, analyzes and processes whether the feed of the non-ideal system has liquid phase stability, and corrects the initial value to obtain a first corrected value of the phase equilibrium parameter; if the feed does not have liquid phase stability, then based on the gas-liquid two-phase flash evaporation model, the first corrected value and multiple system parameters, analyzes and processes whether the feed has gas phase stability, and corrects the first corrected value to obtain a second corrected value of the phase equilibrium parameter; if the feed does not have gas phase stability, then based on the gas-liquid two-phase flash evaporation model, the second corrected value and multiple system parameters, gas-liquid two-phase flash evaporation calculation is performed on the feed to obtain and output the calculation result. Compared with the prior art, the present application uses a strict thermodynamic model to determine the phase state, so that the calculation results can be closer to the actual situation, and the production control system can implement stable control of the chemical production process based on the calculation results.

[0189] It should be noted that the computer-readable medium disclosed above may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0190] In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in combination with an instruction execution system, apparatus, or device. In the present disclosure, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0191] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0192] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0193] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0194] The technical solution provided by the present invention is introduced in detail above. Specific examples are used in this article to illustrate the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An isothermal and isobaric flash calculation method, applied to electronic equipment, for calculating the composition and quantity of gas-liquid two-phase substances after phase separation of a mixture in a non-ideal system, characterized in that: The isothermal and isobaric flash calculation method comprises the steps of: Acquiring a plurality of system parameters of the non-ideal system, wherein the plurality of parameters include the composition of the feed, and also include the system temperature and system pressure of the non-ideal system; estimating the phase equilibrium constant of the non-ideal system to obtain an initial value of the phase equilibrium constant; Based on the gas-liquid two-phase flash model, the initial value and the multiple system parameters, analyzing whether the feed of the non-ideal system has liquid phase stability, outputting the analysis result if it has liquid phase stability, and correcting the initial value to obtain a first corrected value of the phase equilibrium parameter; If the feed does not have liquid phase stability, then based on the gas-liquid two-phase flash model, the first correction value and the plurality of system parameters, whether the feed has gas phase stability is analyzed and processed; if the feed has gas phase stability, the analysis result is output, and the first correction value is corrected to obtain a second correction value of the phase equilibrium parameter; If the feed does not have gas phase stability, a gas-liquid two-phase flash calculation is performed on the feed based on the gas-liquid two-phase flash model, the second correction value and the plurality of system parameters to obtain and output a calculation result.

2. The isothermal and isobaric flash calculation method according to claim 1, characterized in that: The gas-liquid two-phase flash evaporation model includes a mass conservation equation, a phase equilibrium equation, a composition normalization equation and a heat conservation equation.

3. The isothermal and isobaric flash calculation method according to claim 2, characterized in that: The heat conservation equation is the Rachford-Rice equation.

4. The isothermal and isobaric flash calculation method according to claim 1, characterized in that: The method of analyzing whether the feed of the non-ideal system has liquid phase stability based on the gas-liquid two-phase flash model, the initial value and the multiple system parameters, outputting the analysis result if the feed has liquid phase stability, and correcting the initial value to obtain the first corrected value of the phase equilibrium parameter comprises the steps of: calculating a first liquid phase fugacity coefficient based on the composition, the system temperature, and the system pressure; calculating a virtual gas phase composition based on an initial value of the phase equilibrium constant; Calculating a sum of virtual gas phase compositions based on the virtual gas phase compositions; calculating a normalized gas phase composition based on the virtual gas phase composition and the sum of the virtual gas phase composition; calculating a first gas phase fugacity coefficient based on the normalized gas phase composition, the system temperature, and the system pressure; updating the initial value of the phase equilibrium constant according to the first liquid phase fugacity coefficient and the first gas phase fugacity coefficient; Determining whether the initial value converges, if not, returning to the step of calculating the virtual gas phase composition based on the initial value of the phase equilibrium constant, if converged, executing subsequent operations, and using the final initial value as the first correction value; The feed is judged according to the sum of the virtual gas phase compositions. If the sum of the virtual gas phase compositions is less than or equal to zero, the feed has liquid phase stability; otherwise, the feed does not have liquid phase stability.

5. The isothermal and isobaric flash calculation method according to claim 1, characterized in that: If the feed does not have liquid phase stability, then based on the gas-liquid two-phase flash model, the first correction value and the multiple system parameters, whether the feed has gas phase stability is analyzed and processed, if the feed has gas phase stability, the analysis result is output, and the first correction value is corrected to obtain the second correction value of the phase equilibrium parameter, including the steps of: calculating a second gas phase fugacity coefficient based on the composition, the system temperature, and the system pressure; Calculating a virtual liquid phase composition based on a first corrected value of the phase equilibrium constant; Calculating a sum of virtual liquid phase compositions based on the virtual liquid phase compositions; calculating a normalized liquid phase composition based on the virtual liquid phase composition and the sum of the virtual liquid phase composition; calculating a second liquid phase fugacity coefficient based on the normalized liquid phase composition, the system temperature, and the system pressure; updating a first correction value of the phase equilibrium constant according to the second liquid phase fugacity coefficient and the second gas phase fugacity coefficient; Determining whether the first correction value converges, if not, returning to the step of calculating the virtual liquid phase composition based on the first correction value of the phase equilibrium constant, and if converged, executing subsequent operations, and using the final first correction value as the second correction value; The feed is judged according to the sum of the virtual liquid phase compositions. If the sum of the virtual liquid phase compositions is less than or equal to zero, the feed has gas phase stability; otherwise, the feed does not have gas phase stability.

6. The isothermal and isobaric flash calculation method according to claim 1, characterized in that: If the feed does not have gas phase stability, a gas-liquid two-phase flash calculation is performed on the feed based on the second correction value of the gas-liquid two-phase flash model and the multiple system parameters to obtain and output a calculation result, including the steps of: determining whether the second correction value can make the flash problem true; If the flash evaporation problem cannot be established, adjusting the second correction value; If the flash evaporation problem is established, the second correction value is iteratively processed based on the heat conservation equation to obtain an iterative reference value; Divide the range between the second correction value and the iteration reference value into a plurality of value segments, and sequentially perform the calculation based on the constraint value corresponding to each of the value segments until the constraint value converges; When the constraint value converges, the calculation result is output.

7. The isothermal and isobaric flash calculation method according to claim 6, characterized in that: If the flash evaporation problem cannot be established, the second correction value is adjusted, comprising the steps of: Calculating a sum of virtual gas phase compositions and a sum of virtual liquid phase compositions of the feed based on the second correction value; The second correction value is adjusted based on the sum of the virtual gas phase composition and the sum of the virtual liquid phase composition.

8. An isothermal and isobaric flash calculation device, applied to electronic equipment, for calculating the composition and quantity of gas-liquid two-phase substances after phase separation of a mixture in a non-ideal system, characterized in that: The isothermal and isobaric flash calculation device comprises: A parameter acquisition module is configured to acquire a plurality of system parameters of the non-ideal system, wherein the plurality of parameters include the composition of the feed, and also include a system temperature and a system pressure of the non-ideal system; A constant estimation module, configured to estimate the phase equilibrium constant of the non-ideal system to obtain an initial value of the phase equilibrium constant; a liquid phase stability testing module configured to analyze whether the feed of the non-ideal system has liquid phase stability based on the gas-liquid two-phase flash model, the initial value and the multiple system parameters, output the analysis result if it has liquid phase stability, and correct the initial value to obtain a first corrected value of the phase equilibrium parameter; a gas phase stability testing module configured to analyze whether the feed has gas phase stability based on the gas-liquid two-phase flash model, the first correction value and the plurality of system parameters if the feed does not have liquid phase stability, output an analysis result if the feed has gas phase stability, and correct the first correction value to obtain a second correction value of the phase equilibrium parameter; The flash calculation execution module is configured to perform gas-liquid two-phase flash calculation on the feed based on the gas-liquid two-phase flash model, the second correction value and the plurality of system parameters if the feed does not have gas phase stability, and obtain and output a calculation result.

9. An electronic device, characterized in that: The electronic device comprises at least one processor and a memory connected to the processor, wherein: The memory is used to store computer programs or instructions; The processor is used to execute the computer program or instruction so that the electronic device implements the isothermal and isobaric flash evaporation calculation method according to any one of claims 1 to 7.

10. A computer-readable storage medium, applied to an electronic device, characterized in that: The storage medium carries one or more computer programs, and the one or more computer programs can be executed by the electronic device, so that the electronic device implements the isothermal and isobaric flash evaporation calculation method according to any one of claims 1 to 7.

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