A mathematical modeling method, device, storage medium and device for cold box equipment based on digital twin

Abstract

The present invention relates to a mathematical modeling method, device, storage medium and equipment for cold box equipment based on digital twin. The present invention is applicable to the field of chemical equipment simulation. The technical solution of the present invention is a mathematical modeling method for cold box equipment based on digital twin, which is characterized in that the shell side structural parameters of the cold box configured by the user and the initial parameters of the shell side feed logistics are obtained, and the initial parameters include the filling material information in the shell side; the tube side structural parameters of the cold box configured by the user and the initial parameters of the feed logistics in the tube side are obtained, and the initial parameters include the number of tube side logistics stocks and the filling material information in the tube side; the number of areas configured by the user is obtained; based on the number of areas, the cold box is cut into multiple sections along the flow direction of the logistics in the shell side; based on the structural parameters of the shell side and the initial parameters of the shell side feed logistics, as well as the structural parameters of the tube side and the initial parameters of the tube side feed logistics, the export logistics information of the tube and shell side at the outlet of each section is iteratively calculated.

Description

Technical Field

[0001] The present invention relates to a mathematical modeling method, device, storage medium and equipment for cold box equipment based on digital twin, which is applicable to the field of chemical equipment simulation. Background Art

[0002] The cold box is a device used to achieve heat exchange between cold and hot fluids. In the cold box, multiple tube-side logistics can be heat exchanged with the shell-side in different areas. The cold box is divided into shell-and-tube side, which can perform parallel or countercurrent heat exchange. The shell side has one feed, and the tube side can have multiple feeds. Only heat exchange is performed between the materials, and no material transfer is performed. The existing heat exchanger modeling calculation model parameter calculation for dynamic simulation system has the problem of large calculation amount or low simulation accuracy.

[0003] At present, the research on cold box algorithms is mainly concentrated in the steady-state simulation stage. There are relatively few dynamic mathematical modeling of cold box equipment, and most of them are implemented using the cooling curve method. However, the calculation error using the cooling curve method is large. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in response to the above-mentioned problems, a mathematical modeling method, device, storage medium and equipment for cold box equipment based on digital twin are provided.

[0005] The technical solution adopted by the present invention is: a mathematical modeling method for cold box equipment based on digital twin, characterized in that:

[0006] Obtain the shell-side structural parameters of the cold box and the initial parameters of the shell-side feed flow configured by the user, the initial parameters including the filling material information in the shell-side;

[0007] Obtain the cold box pipe structure parameters configured by the user and the initial parameters of the feed logistics in the pipe, which include the number of pipe logistics stocks and the information of the filling materials in the pipe;

[0008] Get the number of regions configured by the user;

[0009] Based on the number of regions, the cold box is cut into multiple regions along the flow direction of the material flow in the shell side;

[0010] Based on the structural parameters of the shell side and the initial parameters of the shell side feed stream, as well as the structural parameters of the tube side and the initial parameters of the tube side feed stream, the outlet stream information of the tube and shell side at the outlet of each section area is iteratively calculated.

[0011] The initial parameter information includes temperature, pressure, mass flow rate, molar flow rate, component molar or mass concentration;

[0012] The outlet logistics information includes temperature, pressure, mass flow rate, molar flow rate, component mole, mass concentration, enthalpy value, entropy value, Gibbs free energy, and internal energy.

[0013] The iterative calculation of the outlet logistics information of the tube and shell side in each region based on the structural parameters of the shell side and the initial parameters of the shell side feed logistics, as well as the structural parameters of the tube side and the initial parameters of the tube side feed logistics, includes:

[0014] Get the user-selected shell-and-tube heat exchange mode of the cold box, parallel flow or countercurrent flow;

[0015] When parallel flow is selected, the feed stream of the shell side is mixed with the material in the first section of the shell side, and the feed stream of each tube side is mixed with the material in the first section of each tube side. The multi-stream heat exchange flash calculation is called. After the flash is completed, the stream exceeding the first section of the shell side flows to the second section and then mixes with the material in the second section of the shell side. The tube side is also processed in the same way, and the multi-stream flash is called again to calculate the temperature of each section of the tube and shell side.

[0016] When countercurrent is selected, the feed flow of each tube side is mixed with the material in the first section of each tube side, and the shell side material is mixed with the material in the last section of the shell side. The multi-stream heat exchange flash evaporation calculation is called. After the flash evaporation is completed, the logistics exceeding the first section of the tube side flows into the second section. The logistics exceeding the first section of the shell side is used as the outlet logistics. The second section of the shell side logistics is mixed with the third section outlet logistics at the previous moment. The multi-stream flash evaporation is called again to calculate the temperature of each section of the tube and shell side.

[0017] Invoke multiple stream heat exchange flash calculation in a certain area, including:

[0018] S1. Assume that the initial temperature of the shell-side logistics at the outlet of this section is TnB0, and TnB1 = TnB0 + Tstep;

[0019] S2. Assume that the initial temperature of the i-th pipeline flow at the outlet of the certain section is TnA0[i], and TnA1[i]=TnA0[i]+Tstep;

[0020] S3, using the secant method to calculate the temperature TnA2[i] of the outlet of the i-th pipe flow in the certain section;

[0021] TnA2[i]=TnA1[i]-(TnA1[i]-TnA0[i]) / (fnA1[i]-fnA0[i])*fnA1[i];

[0022] fnA0[i]=molarA[i]*(H A0,temp [i]

[0023] +△HA staticChange[i]-H A,in [i])-(TnB-TnA0[i])*KA[i];

[0024] Similarly, calculate fnA1[i] and fnA2[i];

[0025] If fnA[i]<=ζ, then the outlet temperature TnA[i] corresponding to the i-th pipe flow in the certain area is output, and TnA[i]=TnA2[i];

[0026] Where: molarA[i] is the inlet molar number of the i-th pipe flow in this section; H A0,temp [i] is the enthalpy of the i-th stream at TnA0[i]; △HA staticChange [i] is the change in enthalpy of the pipe wall of the i-th pipe pass; H A,in [i] is the total inlet enthalpy of the i-th pipe-side logistics; TnB is the outlet temperature of the corresponding shell-side logistics; KA[i] is the product of the heat exchange area corresponding to the i-th logistics and time △t; TnA0[i] is the initial temperature value of the i-th pipe-side logistics at the outlet of this section; TnA2[i] uses the secant method to calculate the new outlet temperature value of the i-th pipe-side logistics in this section; Tstep is the step size; TnA[i] is the outlet temperature of the i-th pipe-side logistics in this section that meets the convergence result; fnA[i] represents the inlet and outlet enthalpy difference of the i-th pipe-side logistics in this section, and fnA0[i], fnA1[i], and fnA2[i] represent the inlet and outlet enthalpy differences when the outlet temperatures are TnA0[i], TnA1[i], and TnA2[i], respectively;

[0027] S4, calculate the heat exchange heatQ[i]=(TnA2[i]-TnB)*KA[i] of the i-th tube flow, and add up the heat exchange of each tube to obtain the total heat exchange totalHeatQ;

[0028] Wherein, heatQ[i] represents the heat exchange of the i-th tube-side logistics in a certain area; totalHeatQ represents the heat exchange of the shell-side logistics in a certain area;

[0029] S5. Calculate the temperature TnB2 of the shell side logistics outlet at a certain area using the secant method;

[0030] TnB2=TnB1-(TnB1-TnB0) / (fnB1-fnB0)*fnB1;

[0031] fnB=molarB*(H B,temp +△H BstaticChange -H B,in )-totalHeatQ;

[0032] If fnB<=ζ, the outlet temperature of the output shell-side logistics in this section is TnB, and TnB=TnB2;

[0033] Wherein, molorB represents the number of moles of shell-side logistics in the import of a certain area; H B,temp Indicates the enthalpy value corresponding to the shell temperature TnB; △H BstaticChange Indicates the change in enthalpy of the shell side; H B,in It represents the inlet enthalpy value of the shell side logistics in this section; fnB represents the inlet and outlet enthalpy difference of the shell side in this section.

[0034] A mathematical modeling device for cold box equipment based on digital twin, characterized by:

[0035] The shell side configuration module is used to obtain the shell side structural parameters of the cold box configured by the user and the initial parameters of the substances in the shell side, which include the initial information of the substances in the shell side;

[0036] The pipe configuration module is used to obtain the cold box pipe structure parameters configured by the user and the initial parameters of the substances in the pipe, which include the number of pipe logistics shares and the initial information of the substances in the pipe;

[0037] The region configuration module is used to obtain the number of regions configured by the user;

[0038] The area cutting module is used to cut the cold box into multiple areas along the flow direction of the shell side logistics based on the number of areas;

[0039] The partitioned iterative calculation module is used to iteratively calculate the export logistics information of the tube and shell side at the outlet of each section area based on the structural parameters of the shell side and the initial parameters of the logistics in the shell side, as well as the structural parameters of the tube side and the initial parameters of the logistics in the tube side.

[0040] The initial logistics information includes temperature, pressure, mass flow rate, molar flow rate, component molar or mass concentration;

[0041] The outlet logistics information includes temperature, pressure, mass flow rate, molar flow rate, component mole, mass concentration, enthalpy value, entropy value, Gibbs free energy, and internal energy.

[0042] The iterative calculation of the outlet logistics information of the tube and shell side in each region based on the structural parameters of the shell side and the initial parameters of the logistics in the shell side, as well as the structural parameters of the tube side and the initial parameters of the logistics in the tube side, includes:

[0043] Get the user-selected shell-and-tube heat exchange mode of the cold box, parallel flow or countercurrent flow;

[0044] When parallel flow is selected, the feed stream of the shell side is mixed with the material in the first section of the shell side, and the feed stream of each tube side is mixed with the material in the first section of each tube side. The multi-stream heat exchange flash calculation is called. After the flash is completed, the stream exceeding the first section of the shell side flows to the second section and then mixes with the material in the second section of the shell side. The tube side is also processed in the same way, and the multi-stream flash is called again to calculate the temperature of each section of the tube and shell side.

[0045] When countercurrent is selected, the feed flow of each tube side is mixed with the material in the first section of each tube side, and the shell side material is mixed with the material in the last section. The multi-stream heat exchange flash evaporation calculation is called. After the flash evaporation is completed, the logistics exceeding the first section of the tube side flows into the second section. The logistics exceeding the first section of the shell side is used as the outlet logistics. The second section of the shell side logistics is mixed with the third section outlet logistics at the previous moment. The multi-stream flash evaporation is called again to calculate the temperature of each section of the tube and shell side.

[0046] Invoke multiple stream heat exchange flash calculation in a certain area, including:

[0047] S1. Assume that the initial temperature of the shell-side logistics at the outlet of this section is TnB0, and TnB1 = TnB0 + Tstep;

[0048] S2. Assume that the initial temperature of the i-th pipeline flow at the outlet of the certain section is TnA0[i], and TnA1[i]=TnA0[i]+Tstep;

[0049] S3, using the secant method to calculate the temperature TnA2[i] of the outlet of the i-th pipe flow in the certain section;

[0050] TnA2[i]=TnA1[i]-(TnA1[i]-TnA0[i]) / (fnA1[i]-fnA0[i])*fnA1[i];

[0051] fnA0[i]=molarA[i]*(H A0,temp [i]

[0052] +△HA staticChange [i]-H A,in [i])-(TnB-TnA0[i])*KA[i];

[0053] Similarly, calculate fnA1[i] and fnA2[i];

[0054] If fnA[i]<=ζ, then the outlet temperature TnA[i] corresponding to the i-th pipe flow in the certain area is output, and TnA[i]=TnA2[i];

[0055] Where: molarA[i] is the inlet molar number of the i-th pipe flow in this section; H A0,temp [i] is the enthalpy of the i-th stream at TnA0[i]; △HA staticChange [i] is the change in enthalpy of the pipe wall of the i-th pipe pass; H A,in [i] is the total inlet enthalpy of the i-th pipe-side logistics; TnB is the outlet temperature of the corresponding shell-side logistics; KA[i] is the product of the heat exchange area corresponding to the i-th logistics and time △t; TnA0[i] is the initial temperature value of the i-th pipe-side logistics at the outlet of this section; TnA2[i] uses the secant method to calculate the new outlet temperature value of the i-th pipe-side logistics in this section; Tstep is the step size; TnA[i] is the outlet temperature of the i-th pipe-side logistics in this section that meets the convergence result; fnA[i] represents the inlet and outlet enthalpy difference of the i-th pipe-side logistics in this section, fnA0[i], fnA1[i], fnA2[i] represent the inlet and outlet enthalpy differences when the outlet temperatures are TnA0[i], TnA1[i], TnA2[i] respectively; fnB represents the inlet and outlet enthalpy difference of the shell-side in this section;

[0056] S4, calculate the heat exchange heatQ[i]=(TnA2[i]-TnB)*KA[i] of the i-th tube flow, and add up the heat exchange of each tube to obtain the total heat exchange totalHeatQ;

[0057] Wherein, heatQ[i] represents the heat exchange of the i-th tube-side logistics in a certain area; totalHeatQ represents the heat exchange of the shell-side logistics in a certain area;

[0058] S5. Calculate the temperature TnB2 of the shell side flow at the outlet of the certain area by using the secant method;

[0059] TnB2=TnB1-(TnB1-TnB0) / (fnB1-fnB0)*fnB1;

[0060] fnB=molarB*(H B,temp +△H BstaticChange -H B,in )-totalHeatQ;

[0061] If fnB<=ζ, the outlet temperature of the output shell-side logistics in this section is TnB, and TnB=TnB2;

[0062] Wherein, molorB represents the number of moles of shell-side logistics in the import of a certain area; H B,temp Indicates the enthalpy value corresponding to the shell temperature TnB; △H BstaticChange Indicates the change in enthalpy of the shell side; H B,inIt indicates the inlet enthalpy of the shell side logistics in this certain area.

[0063] A storage medium having stored thereon a computer program executable by a processor, characterized in that when the computer program is executed, the steps of the mathematical modeling method of cold box equipment based on digital twin are implemented.

[0064] A computer device comprises a memory and a processor, wherein the memory stores a computer program executable by the processor, and wherein the computer program, when executed, implements the steps of the mathematical modeling method of cold box equipment based on digital twins.

[0065] The beneficial effect of the present invention is that compared with the existing cooling curve method, the present invention divides the cold box equipment into areas and performs strict flash calculations in each area to ensure that the calculation results are more consistent with the actual operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 A flowchart of an embodiment.

[0067] Figure 2 Schematic diagram of partition calculation in the embodiment.

[0068] Figure 3 Schematic diagram of the structure of the device in the embodiment.

[0069] 1. Shell configuration module; 2. Tube configuration module; 3. Region configuration module; 4. Region cutting module; 5. Partition iterative calculation module. DETAILED DESCRIPTION

[0070] This embodiment is a mathematical modeling method for cold box equipment based on digital twins, which is characterized by:

[0071] A. Obtain the shell-side structural parameters of the cold box and the initial parameters of the substances in the shell-side configured by the user, which include the initial information of the substances in the shell-side.

[0072] During the use of the cold box, the user can select the structural parameters of the shell side according to the actual situation, including shape and direction, and fill in the required diameter, height and wall thickness of the shell side, and at the same time determine whether the bottom outlet of the shell side contains the static pressure of the liquid column.

[0073] During the use of the cold box, the user can determine the initial logistics information according to the engineering conditions, including temperature, pressure, mass flow rate, molar flow rate, component molar or mass concentration, etc.

[0074] B. Obtain the cold box pipe structure parameters configured by the user and the initial parameters of the substances in the pipe, which include the number of pipe logistics shares n and the initial information of the substances in the pipe.

[0075] Users can fill in the structural parameters of the pipe according to the actual conditions of the project, including diameter, size and wall thickness, and can also select the pipe direction according to the actual situation. In actual application, users can fill in the pipe size according to the required number of pipes.

[0076] Users can calibrate the initial logistics information of the pipeline according to the actual engineering conditions, including temperature, pressure, mass flow rate, molar flow rate, component molar or mass concentration, etc.

[0077] C. Get the number of regions configured by the user. In order to achieve accurate simulation of multi-stream heat exchangers, the multi-stream heat exchangers are cut into multiple regions. Users can freely configure the number of regions. The more regions there are, the more accurate the simulation is. However, the amount of calculation is large and the computer's computing power is consumed. Users can consider both situations at the same time and choose the number of regions as appropriate.

[0078] D. Based on the number of zones, the cold box is cut into multiple zones along the flow direction of the material flow in the shell.

[0079] E. Based on the structural parameters of the shell side and the initial parameters of the substances in the shell side, as well as the structural parameters of the tube side and the initial parameters of the substances in the tube side, the export logistics information of the tube and shell side at the outlet of each section is iteratively calculated. The export logistics information includes temperature, pressure, mass flow rate, molar flow rate, component mole, mass concentration, enthalpy value, entropy value, Gibbs free energy, internal energy, etc.

[0080] In this embodiment, step E includes:

[0081] Get the selected shell and tube heat exchange mode of the cold box, co-current or counter-current;

[0082] When parallel flow is selected, the feed stream of the shell side is mixed with the material in the first section of the shell side, and the feed stream of each tube side is mixed with the material in the first section of each tube side. The multi-stream heat exchange flash calculation is called. After the flash is completed, the stream exceeding the first section of the shell side flows to the second section and then mixes with the material in the second section of the shell side. The tube side is also processed in the same way, and the multi-stream flash is called again. By analogy, the temperature of each section of the tube and shell side is calculated.

[0083] When countercurrent is selected, the feed flow of each tube side is mixed with the material in the first section of each tube side, and the shell side material is mixed with the material in the last section of the shell side. The multi-stream heat exchange flash evaporation calculation is called. After the flash evaporation is completed, the logistics exceeding the first section of the tube side flows into the second section. The logistics exceeding the first section of the shell side is used as the outlet logistics. The second section of the shell side is mixed with the third section outlet logistics at the previous moment, and the multi-stream flash evaporation is called again. And so on, the temperature of each section of the shell and tube side is calculated.

[0084] In this embodiment, the multi-stream heat exchange flash calculation is called in a certain area, including:

[0085] Invoke multiple stream heat exchange flash calculation in a certain area, including:

[0086] S1. Assume that the initial temperature of the shell-side logistics at the outlet of this section is TnB0, and TnB1 = TnB0 + Tstep;

[0087] S2. Assume that the initial temperature of the i-th pipeline flow at the outlet of the certain section is TnA0[i], and TnA1[i]=TnA0[i]+Tstep;

[0088] S3, using the secant method to calculate the temperature TnA2[i] of the outlet of the i-th pipe flow in the certain section;

[0089] TnA2[i]=TnA1[i]-(TnA1[i]-TnA0[i]) / (fnA1[i]-fnA0[i])*fnA1[i];

[0090] fnA0[i]=molarA[i]*(H A0,temp [i]

[0091] +△HA staticChange [i]-H A,in [i])-(TnB-TnA0[i])*KA[i];

[0092] fnA1[i]=molarA[i]*(H A1,temp [i]

[0093] +△HA staticChange [i]-H A,in [i])-(TnB-TnA1[i])*KA[i];

[0094] fnA2[i]=molarA[i]*(H A2,temp [i]

[0095] +△HA staticChange [i]-H A,in [i])-(TnB-TnA2[i])*KA[i];

[0096] If fnA[i]<=ζ, then the outlet temperature TnA[i] corresponding to the i-th pipe flow in the certain area is output, and TnA[i]=TnA2[i];

[0097] Where: molarA[i] is the inlet molar number of the i-th pipe flow in this section; H A0,temp [i] is the enthalpy of the i-th stream at TnA0[i]; △HA staticChange [i] is the change in enthalpy of the pipe wall of the i-th pipe pass; H A,in[i] is the total inlet enthalpy of the i-th pipe-side logistics; TnB is the outlet temperature of the corresponding shell-side logistics; KA[i] is the product of the heat exchange area corresponding to the i-th logistics and time △t, in KJ / ℃; TnA0[i] is the initial temperature value of the i-th pipe-side logistics at the outlet of this section; TnA2[i] uses the secant method to calculate the new outlet temperature value of the i-th pipe-side logistics in this section; Tstep is the step size; TnA[i] is the outlet temperature of the i-th pipe-side logistics in this section that meets the convergence result; fnA[i] represents the inlet and outlet enthalpy difference of the i-th pipe-side logistics in this section, and fnA0[i], fnA1[i], and fnA2[i] represent the inlet and outlet enthalpy differences when the outlet temperatures are TnA0[i], TnA1[i], and TnA2[i], respectively;

[0098] S4, calculate the heat exchange heatQ[i]=(TnA2[i]-TnB)*KA[i] of the i-th pipe flow, and accumulate them to obtain the total heat exchange totalHeatQ=heatQ[1]+…+heatQ[n];

[0099] Wherein, heatQ[i] represents the heat exchange of the i-th tube-side logistics in a certain area; totalHeatQ represents the heat exchange of the shell-side logistics in a certain area;

[0100] S5. Calculate the temperature TnB2 of the shell side flow at the outlet of the certain area by using the secant method;

[0101] TnB2=TnB1-(TnB1-TnB0) / (fnB1-fnB0)*fnB1;

[0102] fnB=molarB*(H B,temp +△H BstaticChange -H B,in )-totalHeatQ;

[0103] If fnB<=ζ, the outlet temperature of the output shell-side logistics in this section is TnB, and TnB=TnB2;

[0104] Wherein, molorB represents the number of moles of shell-side logistics in the import of a certain area; H B,temp Indicates the enthalpy value corresponding to the shell temperature TnB; △H BstaticChange Indicates the change in enthalpy of the shell side; H B,in It represents the inlet enthalpy value of the shell side logistics in this section; fnB represents the inlet and outlet enthalpy difference of the shell side in this section.

[0105] In this embodiment, each time TnB is updated, TnA[i] needs to be recalculated to obtain the corresponding heat exchange amount totalHeatQ.

[0106] In this embodiment, the molar flow rates of the tube and shell processes are calculated based on the relationship between flow rate and pressure, including:

[0107] 1) Pipeline:

[0108] Flow-pressure relationship:

[0109]

[0110]

[0111] In the formula, F mass_tube =Tube fluid mass flow rate, kg / h

[0112] F molar_tube = molar flow rate of fluid in tube, kmol / h

[0113] k = flow coefficient

[0114] P tube_in =Tube inlet pressure, kPa

[0115] P tube_out =Tube outlet pressure, kPa

[0116] ρ mass_tube = tube side fluid mass density, kg / m3

[0117] ρ molar_tube = tube-side fluid molar density, kmol / m3

[0118] In this embodiment, the user inputs the mass flow rate, mass density and pressure drop, and uses formula (1) to calculate the flow coefficient k; formula (2) is used in model calculation, namely molar flow rate and molar density.

[0119] 2) Shell side:

[0120] The shell side has one feed and one discharge, where the inlet pressure is the same as the pressure of the shell side gas phase discharge:

[0121] P shell_in =P shell_out (3)

[0122] Where P shell_in = Shell inlet pressure, kPa;

[0123] P shell_out = Shell side outlet pressure, kPa;

[0124] The shell side liquid phase outlet pressure is equal to the gas phase outlet pressure plus the static pressure of the liquid column.

[0125] The relationship between the shell side inlet and outlet pressures and flow rates obtained based on the shell side volume balance

[0126]

[0127] Among them, F in is the molar flow rate of the feed stream, F out is the molar flow rate of the discharge, MW in MW out are the average molecular weight of the feed stream and the discharge stream, respectively; ρ is the mass density of the substance in the tower, in kg / m3; Z is the compression factor of the gas in the tower, R is the gas constant, and T is the temperature in the tower. v It is the number of moles of gas in the tower, in kmol.

[0128] This embodiment also provides a mathematical modeling device for cold box equipment based on digital twins, including a shell-side configuration module, a tube-side configuration module, an area configuration module, an area cutting module and a partition iterative calculation module.

[0129] In this example, the shell configuration module is used to obtain the user-configured cold box shell structure parameters and the initial parameters of the materials in the shell, which include the initial information of the materials in the shell; the tube configuration module is used to obtain the user-configured cold box tube structure parameters and the initial parameters of the materials in the tube, which include the number of tube logistics and the initial information of the materials in the tube; the area configuration module is used to obtain the number of areas configured by the user; the area cutting module is used to cut the cold box into multiple areas along the flow direction of the shell logistics based on the number of areas; the partition iterative calculation module is used to iteratively calculate the export logistics information of the tube and shell at the outlet of each area based on the shell structure parameters and the initial parameters of the materials in the shell, as well as the tube structure parameters and the initial parameters of the materials in the tube.

[0130] This embodiment also provides a storage medium on which a computer program that can be executed by a processor is stored. When the computer program is executed, the steps of the mathematical modeling method of cold box equipment based on digital twin in this example are implemented.

[0131] This embodiment also provides a computer device having a memory and a processor, wherein the memory stores a computer program that can be executed by the processor, and when the computer program is executed, the steps of the mathematical modeling method of the cold box equipment based on digital twin in this example are implemented.

Claims

1. A mathematical modeling method for cold box equipment based on digital twin, characterized by: Obtain the shell-side structural parameters of the cold box and the initial parameters of the substances in the shell-side configured by the user, and the initial parameters include the initial information of the substances in the shell-side; Obtain the cold box pipe structure parameters configured by the user and the initial parameters of the substances in the pipe, which include the number of pipe logistics shares and the initial information of the substances in the pipe; Get the number of regions configured by the user; Based on the number of regions, the cold box is cut into multiple regions along the flow direction of the material flow in the shell side; Based on the structural parameters of the shell side and the initial parameters of the substances in the shell side, as well as the structural parameters of the tube side and the initial parameters of the substances in the tube side, the export logistics information of the tube and shell side at the outlet of each section is iteratively calculated; The iterative calculation of the outlet logistics information of the tube and shell side in each region based on the structural parameters of the shell side and the initial parameters of the substances in the shell side, as well as the structural parameters of the tube side and the initial parameters of the substances in the tube side, includes: Get the user-selected shell-and-tube heat exchange mode of the cold box, parallel flow or countercurrent flow; When parallel flow is selected, the feed stream of the shell side is mixed with the material in the first section of the shell side, and the feed stream of each tube side is mixed with the material in the first section of each tube side. The multi-stream heat exchange flash calculation is called. After the flash is completed, the stream exceeding the first section of the shell side flows to the second section and then mixes with the material in the second section of the shell side. The tube side is also processed in the same way, and the multi-stream flash is called again to calculate the temperature of each section of the tube and shell side. When countercurrent is selected, the feed flow of each tube side is mixed with the material in the first section of each tube side, and the shell side material is mixed with the material in the next section. The multi-stream heat exchange flash evaporation calculation is called. After the flash evaporation is completed, the logistics exceeding the first section of the tube side flows into the second section. The logistics exceeding the first section of the shell side is used as the outlet logistics. The second section of the shell side logistics is mixed with the third section outlet logistics at the previous moment. The multi-stream flash evaporation is called again to calculate the temperature of each section of the tube and shell side.

2. The mathematical modeling method for cold box equipment based on digital twin according to claim 1 is characterized in that: The initial information includes temperature, pressure, mass flow rate, molar flow rate, component molar or mass concentration; The outlet logistics information includes temperature, pressure, mass flow rate, molar flow rate, component mole, mass concentration, enthalpy value, entropy value, Gibbs free energy, and internal energy.

3. The mathematical modeling method for cold box equipment based on digital twin according to claim 1 is characterized in that: Invoke multiple stream heat exchange flash calculation in a certain area, including: S1. Assume that the initial temperature of the shell-side logistics at the outlet of this section is TnB0, and TnB1 = TnB0 + Tstep; S2. Assume that the initial temperature of the i-th pipeline flow at the outlet of the certain section is TnA0[i], and TnA1[i]=TnA0[i]+Tstep; S3, using the secant method to calculate the temperature TnA2[i] of the outlet of the i-th pipe flow in the certain section; TnA2[i]=TnA1[i]-(TnA1[i]-TnA0[i]) / (fnA1[i]-fnA0[i])*fnA1[i]; fnA0[i]=molarA[i]*(H A0,temp [i] +△HA staticChange [i]-H A,in [i])-(TnB-TnA0[i])*KA[i]; Similarly, calculate fnA1[i] and fnA2[i]; If fnA[i]<=ζ, then the outlet temperature TnA[i] corresponding to the i-th pipe flow in the certain area is output, and TnA[i]=TnA2[i]; Where: molarA[i] is the inlet molar number of the i-th pipe flow in this section; H A0,temp [i] is the enthalpy of the i-th stream at TnA0[i]; △HA staticChange [i] is the change in enthalpy of the pipe wall of the i-th pipe pass; H A,in [i] is the total inlet enthalpy of the i-th pipe-side logistics; TnB is the outlet temperature of the corresponding shell-side logistics; KA[i] is the product of the heat exchange area corresponding to the i-th logistics and time △t; TnA0[i] is the initial temperature value of the i-th pipe-side logistics at the outlet of this section; TnA2[i] uses the secant method to calculate the new outlet temperature value of the i-th pipe-side logistics in this section; Tstep is the step size; TnA[i] is the outlet temperature of the i-th pipe-side logistics in this section that meets the convergence result; fnA[i] represents the inlet and outlet enthalpy difference of the i-th pipe-side logistics in this section, and fnA0[i], fnA1[i], and fnA2[i] represent the inlet and outlet enthalpy differences when the outlet temperatures are TnA0[i], TnA1[i], and TnA2[i], respectively; S4, calculate the heat exchange heatQ[i]=(TnA2[i]-TnB)*KA[i] of the i-th pipe flow, and accumulate them to obtain the total heat exchange totalHeatQ; Wherein, heatQ[i] represents the heat exchange of the i-th tube-side logistics in a certain area; totalHeatQ represents the heat exchange of the shell-side logistics in a certain area; S5. Calculate the temperature TnB2 of the shell side flow at the outlet of the certain area by using the secant method; TnB2=TnB1-(TnB1-TnB0) / (fnB1-fnB0)*fnB1; fnB=molarB*(H B,temp +△H BstaticChange -H B,in )-totalHeatQ; If fnB<=ζ, the outlet temperature of the output shell-side logistics in this section is TnB, and TnB=TnB2; Wherein, molorB represents the number of moles of shell-side logistics in the import of a certain area; H B,temp Indicates the enthalpy value corresponding to the shell temperature TnB; △H BstaticChange Indicates the change in enthalpy of the shell side; H B,in It represents the inlet enthalpy value of the shell side logistics in this section; fnB represents the inlet and outlet enthalpy difference of the shell side in this section.

4. A mathematical modeling device for cold box equipment based on digital twin, characterized in that: The shell side configuration module is used to obtain the shell side structural parameters of the cold box configured by the user, the initial parameters of the materials in the shell side, and the feed flow information. The initial parameters include the initial information of the materials in the shell side. The pipe configuration module is used to obtain the cold box pipe structure parameters configured by the user and the initial parameters of the substances in the pipe, which include the number of pipe logistics shares and the initial information of the substances in the pipe; The region configuration module is used to obtain the number of regions configured by the user; The area cutting module is used to cut the cold box into multiple areas along the flow direction of the shell side logistics based on the number of areas; A partitioned iterative calculation module is used to iteratively calculate the export logistics information of the tube and shell side at the outlet of each section area based on the structural parameters of the shell side and the initial parameters of the substances in the shell side, as well as the structural parameters of the tube side and the initial parameters of the substances in the tube side; The iterative calculation of the outlet logistics information of the tube and shell side in each region based on the structural parameters of the shell side and the initial parameters of the substances in the shell side, as well as the structural parameters of the tube side and the initial parameters of the substances in the tube side, includes: Get the user-selected shell-and-tube heat exchange mode of the cold box, parallel flow or countercurrent flow; When parallel flow is selected, the feed stream of the shell side is mixed with the material in the first section of the shell side, and the feed stream of each tube side is mixed with the material in the first section of each tube side. The multi-stream heat exchange flash calculation is called. After the flash is completed, the stream exceeding the first section of the shell side flows to the second section and then mixes with the material in the second section of the shell side. The tube side is also processed in the same way, and the multi-stream flash is called again to calculate the temperature of each section of the tube and shell side. When countercurrent is selected, the feed flow of each tube side is mixed with the material in the first section of each tube side, and the shell side material is mixed with the material in the last section. The multi-stream heat exchange flash evaporation calculation is called. After the flash evaporation is completed, the logistics exceeding the first section of the tube side flows into the second section. The logistics exceeding the first section of the shell side is used as the outlet logistics. The second section of the shell side logistics is mixed with the third section outlet logistics at the previous moment. The multi-stream flash evaporation is called again to calculate the temperature of each section of the tube and shell side.

5. The mathematical modeling device for cold box equipment based on digital twin according to claim 4 is characterized in that: The initial information includes temperature, pressure, mass flow rate, molar flow rate, component molar or mass concentration; The outlet logistics information includes temperature, pressure, mass flow rate, molar flow rate, component mole, mass concentration, enthalpy value, entropy value, Gibbs free energy, and internal energy.

6. The mathematical modeling device for cold box equipment based on digital twin according to claim 4 is characterized in that: Invoke multiple stream heat exchange flash calculation in a certain area, including: S1. Assume that the initial temperature of the shell-side logistics at the outlet of this section is TnB0, and TnB1 = TnB0 + Tstep; S2. Assume that the initial temperature of the i-th pipeline flow at the outlet of the certain section is TnA0[i], and TnA1[i]=TnA0[i]+Tstep; S3, using the secant method to calculate the temperature TnA2[i] of the outlet of the i-th pipe flow in the certain section; TnA2[i]=TnA1[i]-(TnA1[i]-TnA0[i]) / (fnA1[i]-fnA0[i])*fnA1[i]; fnA0[i]=molarA[i]*(H A0,temp [i] +△HA staticChange [i]-H A,in [i])-(TnB-TnA0[i])*KA[i]; Similarly, calculate fnA1[i] and fnA2[i]; If fnA[i]<=ζ, then the outlet temperature TnA[i] corresponding to the i-th pipe flow in the certain area is output, and TnA[i]=TnA2[i]; Where: molarA[i] is the inlet molar number of the i-th pipe flow in this section; H A0,temp [i] is the enthalpy of the i-th stream at TnA0[i]; △HA staticChange [i] is the change in enthalpy of the pipe wall of the i-th pipe pass; H A,in [i] is the total inlet enthalpy of the i-th pipe-side logistics; TnB is the outlet temperature of the corresponding shell-side logistics; KA[i] is the product of the heat exchange area corresponding to the i-th logistics and time △t; TnA0[i] is the initial temperature value of the i-th pipe-side logistics at the outlet of this section; TnA2[i] uses the secant method to calculate the new outlet temperature value of the i-th pipe-side logistics in this section; Tstep is the step size; TnA[i] is the outlet temperature of the i-th pipe-side logistics in this section that meets the convergence result; fnA[i] represents the inlet and outlet enthalpy difference of the i-th pipe-side logistics in this section, fnA0[i], fnA1[i], fnA2[i] represent the inlet and outlet enthalpy differences when the outlet temperatures are TnA0[i], TnA1[i], TnA2[i] respectively; fnB represents the inlet and outlet enthalpy difference of the shell-side in this section; S4, calculate the heat exchange heatQ[i]=(TnA2[i]-TnB)*KA[i] of the i-th pipe flow, and accumulate them to obtain the total heat exchange totalHeatQ; Wherein, heatQ[i] represents the heat exchange of the i-th tube-side logistics in a certain area; totalHeatQ represents the heat exchange of the shell-side logistics in a certain area; S5. Calculate the temperature TnB2 of the shell side flow at the outlet of the certain area by using the secant method; TnB2=TnB1-(TnB1-TnB0) / (fnB1-fnB0)*fnB1; fnB=molarB*(H B,temp +△H BstaticChange -H B,in )-totalHeatQ; If fnB<=ζ, the outlet temperature of the output shell-side logistics in this section is TnB, and TnB=TnB2; Wherein, molorB represents the number of moles of shell-side logistics in the import of a certain area; H B,temp Indicates the enthalpy value corresponding to the shell temperature TnB; △H BstaticChange Indicates the change in enthalpy of the shell side; H B,in It indicates the inlet enthalpy of the shell side logistics in this certain area.

7. A storage medium having stored thereon a computer program executable by a processor, characterized in that: When the computer program is executed, the steps of the mathematical modeling method of cold box equipment based on digital twin according to any one of claims 1 to 3 are implemented.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program executable by the processor, wherein: When the computer program is executed, the steps of the mathematical modeling method of cold box equipment based on digital twin according to any one of claims 1 to 3 are implemented.

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