LNG receiving station pipe network scheduling method and device based on two-stage optimization

Abstract

The invention discloses an LNG receiving station pipe network scheduling method and device based on two-stage optimization, and relates to the field of scheduling control, and the method comprises the steps: adjusting the initial operation parameters of each device in an LNG receiving station based on the constraint relation between the initial operation parameters; when the initial operation parameter meets the condition that the energy consumption objective function reaches the minimum value and the value of the initial operation parameter is within the corresponding operation parameter range, determining the initial operation parameter as a to-be-corrected operation parameter; inputting the to-be-corrected operation parameters into the correction model to obtain scheduling operation parameters; and each device in the LNG receiving station is controlled based on the scheduling operation parameters. When the energy consumption is the lowest, it is determined that adjustment of the operation parameters is finished, the value range of the parameters is normal in the adjustment process, the constraint relation between the parameters is considered, and the situation that the obtained operation parameters do not meet actual requirements is avoided. The adjusted parameters need to be corrected through the correction model to control the liquefied natural gas, and finally the parameters of the liquefied natural gas station are controlled more accurately.

Description

Technical Field

[0001] The present invention relates to the field of dispatching control, and in particular to a method and device for dispatching a pipeline network of an LNG receiving station based on double-stage optimization. Background Art

[0002] Traditional equipment startup and shutdown operations at LNG (liquefied natural gas) receiving terminals have long relied on manual experience or pre-set, fixed automation logic, resulting in bottlenecks such as slow response and insufficient dynamic adaptability to complex operating conditions. For example, the "one-button start / stop" feature, a typical existing solution, reduces operational complexity to a certain extent. However, it essentially solidifies the operator's empirical rules into program instructions, lacking the ability to deeply analyze the coupling relationships between multiple devices, real-time operating conditions, and historical operating patterns. Amidst the rapid advancements in artificial intelligence technology, intelligent decision-making systems based on large models have become a research hotspot in the industrial control field. However, purely data-driven large model solutions have significant limitations in LNG receiving terminal scenarios. Because the process involves extreme conditions such as high pressure and low temperature, and because of the strong coupling between equipment (e.g., changes in tank liquid levels triggering cascading pump startup and shutdown), large models trained solely on data can produce infeasible solutions that conflict with physical rules (e.g., violating the minimum discharge flow requirement for high-pressure pumps). At the same time, although existing optimization algorithms based on mathematical programming (such as linear programming and dynamic programming) can strictly follow equipment safety constraints, they have difficulty handling real-time data fusion problems, making it more difficult to control various equipment in liquefied natural gas receiving stations and reducing control efficiency accordingly. Summary of the Invention

[0003] The present invention aims to provide a method and apparatus for dispatching an LNG receiving station pipeline network based on dual-stage optimization. This method determines the end of operating parameter adjustment when energy consumption is minimized, maintains a normal parameter range during the adjustment process, and considers the constraints between parameters to avoid operating parameters that do not meet actual requirements. The adjusted parameters must be calibrated using a calibration model before controlling LNG, ultimately achieving more accurate parameter control of the LNG station.

[0004] To solve the above technical problems, the present invention provides a pipeline network scheduling method for an LNG receiving station based on two-stage optimization, which is applied to a processor. The equipment in the LNG receiving station includes a storage tank, a recondenser, a high-pressure pump, a low-pressure pump, a seawater pump, a vaporizer and a compressor. The input end of the low-pressure pump serves as the output end of the storage tank, the evaporation end of the storage tank is connected to the input end of the compressor, the output end of the compressor is connected to the first input end of the recondenser, the output end of the low-pressure pump is respectively connected to the input end of the high-pressure pump and the second input end of the recondenser, the output end of the recondenser is connected to the input end of the high-pressure pump, the output end of the high-pressure pump is connected to the liquefied natural gas input end of the vaporizer, and the output end of the seawater pump is connected to the seawater input end of the vaporizer;

[0005] The LNG receiving station pipeline network scheduling method based on two-stage optimization includes:

[0006] Establishing initial operating parameters for each device in the LNG receiving station, wherein the initial operating parameters include operating load and output;

[0007] Constructing an energy consumption target function, wherein a value of the energy consumption target function is positively correlated with the energy consumption of each of the devices;

[0008] Adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters, and determining the initial operating parameters as the operating parameters to be corrected when the initial operating parameters satisfy the energy consumption objective function to reach a minimum value and the values of the initial operating parameters are within the corresponding operating parameter ranges;

[0009] Inputting the operating parameters to be corrected into the correction model to obtain the scheduling operating parameters output by the correction model after correcting the operating parameters to be corrected;

[0010] Each device in the LNG receiving station is controlled based on the scheduling operation parameters.

[0011] On the other hand, the energy consumption objective function is constructed, including:

[0012] Construct an energy consumption objective function, the expression of which is:

[0013] ;

[0014] in, is the minimum energy consumption of the LNG receiving station at time t, is the energy consumption of all low-pressure pumps at time t, is the energy consumption of all compressors at time t, is the energy consumption of all high-pressure pumps at time t, is the energy consumption of all seawater pumps at time t, and T is the maximum time.

[0015] On the other hand, the energy consumption objective function is constructed, including:

[0016] Under the condition that the operating state constraints of the low-pressure pumps are satisfied, the energy consumption of each low-pressure pump is determined. The energy consumption of each low-pressure pump is expressed as follows:

[0017] ;

[0018] The expression of the low-pressure pump operating state constraint is:

[0019] ;

[0020] in, is the energy consumption of the lth low-pressure pump in the kth storage tank at time t, is the pumping volume of the lth low-pressure pump in the kth storage tank at time t, is the maximum power consumption of the low-pressure pump, is the maximum volume flow of the low-pressure pump, is the minimum volume flow rate of the low-pressure pump;

[0021] Under the condition that the startup quantity constraint of the low-pressure pumps is satisfied, the energy consumption of all low-pressure pumps is determined according to the energy consumption of each low-pressure pump. The energy consumption of all low-pressure pumps is expressed as follows:

[0022] ;

[0023] The expression for the startup quantity constraint of the low-pressure pump is:

[0024] ;

[0025] in, It is a binary variable. When the value is 1, it means that the l-th low-pressure pump in the k-th storage tank is enabled at time t. K is the total number of storage tanks, and L is the total number of low-pressure pumps in the storage tank. is the number of low-pressure pumps started in the k-th storage tank at time t, The maximum number of low-pressure pumps enabled.

[0026] On the other hand, the energy consumption objective function is constructed, including:

[0027] Under the condition that the operating state constraints of the compressor are met, the energy consumption of each compressor is determined. The expression of the energy consumption of each compressor is:

[0028] ;

[0029] The operating state constraint expression of the compressor is:

[0030] ;

[0031] in, is the energy consumption of the nth compressor at time t, is the energy consumption of the compressor with load level s, is the fraction of time that the nth compressor operates at load level s at time t, which accounts for the entire compressor operation cycle, where S is the maximum load level of the compressor;

[0032] The energy consumption of all compressors is determined according to the energy consumption of each compressor. The energy consumption of all compressors is expressed as follows:

[0033] ;

[0034] Where N is the total number of compressors.

[0035] On the other hand, the energy consumption objective function is constructed, including:

[0036] The number of high-pressure pumps that are turned on is determined. The expression for the number of high-pressure pumps that are turned on is:

[0037] ;

[0038] The energy consumption of each high-pressure pump is determined. The energy consumption of each high-pressure pump is expressed as follows:

[0039] ;

[0040] in, It is a binary variable. When it is 1, it means that the h-th high-pressure pump is enabled at time t. is the number of high-pressure pumps started at time t, is the energy consumption of the h-th high-pressure pump at time t, is the pumping volume of the hth high-pressure pump at time t, is the maximum power consumption of the high-pressure pump, is the maximum volume flow of the high-pressure pump, and H is the total number of high-pressure pumps;

[0041] Under the condition that the operating state constraint of the high-pressure pump and the startup quantity constraint of the high-pressure pump are satisfied, the energy consumption of all high-pressure pumps is determined according to the energy consumption of each high-pressure pump. The energy consumption of all high-pressure pumps is expressed as follows:

[0042] ;

[0043] The expression of the operating state constraint of the high-pressure pump is:

[0044] ;

[0045] The expression for the startup quantity constraint of the high-pressure pump is:

[0046] ;

[0047] in, The BHPN high-pressure pump starts at time t, is the energy consumption of the BHPN high-pressure pump at time t, is the minimum volume flow rate of the high-pressure pump, is the maximum number of high-pressure pumps to be started, and a total of BHPN high-pressure pumps are started at time t.

[0048] On the other hand, the energy consumption objective function is constructed, including:

[0049] Under the condition that the operation constraints of the seawater pump are met, the energy consumption of each seawater pump is determined. The expression of the energy consumption of each seawater pump is:

[0050] ;

[0051] The expression of the operation constraint of the seawater pump is:

[0052] ;

[0053] The energy consumption of all seawater pumps is determined based on the energy consumption of each seawater pump. The energy consumption of all seawater pumps is expressed as follows:

[0054] ;

[0055] in, is the energy consumption of the wth seawater pump at time t, is the pumping capacity of the wth seawater pump at time t, is the maximum energy consumption of the seawater pump, is the maximum volume flow rate of the seawater pump, is the minimum volume flow rate of the seawater pump, It is a binary variable. When the value is 1, it means that the wth seawater pump is activated at time t, and W is the total number of seawater pumps.

[0056] On the other hand, before adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters, the method further includes:

[0057] Determine the conservation relationship of the output volume flow of the storage tank, the high-pressure pump, the compressor, the recondenser, and the vaporizer, wherein the conservation relationship of the output volume flow includes:

[0058] The conservation relationship of the volume flow rate of the tank output is expressed as follows:

[0059] ;

[0060] in, is the volume flow rate of all storage tanks output at time t, is the volume flow directly input into the high-pressure pipe network at time t, is the volume flow rate added to the recondenser at time t, is the amount input to the tank truck filling area at time t, It is a binary variable. When it is 1, it means that the l-th low-pressure pump in the k-th storage tank is enabled at time t. is the pumping volume of the lth low-pressure pump of the kth storage tank at time t, K is the total number of storage tanks, and L is the total number of low-pressure pumps in the storage tank;

[0061] The conservation relationship of boil-off gas in a storage tank is expressed as follows:

[0062] ;

[0063] in, is the volume flow rate of all compressors at time t, is the volume flow rate of the nth compressor at time t, is the volume flow rate of boil-off gas from all storage tanks at time t, is the volume flow rate of boil-off gas from the kth tank at time t;

[0064] The conservation relationship of the high-pressure pump output volume flow rate is expressed as follows:

[0065] ;

[0066] in, is the volume flow rate output by all high-pressure pumps at time t, is the amount input from the recondenser at time t, The BHPN high-pressure pump starts at time t, is the pumping volume of the BHPN high-pressure pump at time t, The hth high-pressure pump starts at time t, is the maximum volume flow of the high-pressure pump, and BHPN high-pressure pumps are started at time t;

[0067] The conservation relationship of the recondenser output volume flow rate is expressed as follows:

[0068] ;

[0069] The conservation relationship of the compressor output volume flow rate is expressed as follows:

[0070] ;

[0071] in, is the volume flow rate of the carburetor output at time t, It is a binary variable. When it is 1, it means that the oth carburetor is started at time t. is the output volume flow rate of the oth vaporizer at time t, and O is the total number of vaporizers;

[0072] The conservation relationship of the volume flow rate of the seawater pump is expressed as follows:

[0073] ;

[0074] in, is the volume flow rate of seawater required by the vaporizer, is the seawater heat required by the evaporator at time t, is the specific heat capacity of seawater, is the density of seawater, is the temperature difference between the outlet and inlet of liquefied natural gas at time t, It is a binary variable. When the value is 1, it means that the wth seawater pump is activated at time t. is the volume flow rate pumped out by the wth seawater pump at time t, and W is the total number of seawater pumps;

[0075] Adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters includes:

[0076] The initial operating parameters are adjusted based on a conservation relationship of the output volume flow rate between the initial operating parameters.

[0077] On the other hand, the calculation relationship of the volume flow rate of the boil-off gas of the kth storage tank at time t is:

[0078] ;

[0079] The calculation relationship of the volume flow of the nth compressor at time t is:

[0080] ;

[0081] The calculation formula for the volume flow of the nth compressor at time t under load level s is:

[0082] ;

[0083] in, is the maximum daily volatility of the storage tank, is the liquid level of the kth tank at time t, is the cross-sectional area of the kth tank, N is the total number of compressors, is the volume flow of the nth compressor at time t under load level s, is the fraction of the time that the nth compressor operates at load level s at time t in the entire compressor operation cycle, is the load fraction corresponding to load level s, is the volume flow of the compressor at maximum load;

[0084] The calculation formula for the seawater heat required by the vaporizer at time t is:

[0085] ;

[0086] The calculation formula for the seawater heat required by the oth vaporizer at time t is:

[0087] ;

[0088] The expression of the operating constraints of the vaporizer is;

[0089] ;

[0090] in, is the seawater heat required by the oth evaporator at time t, is the density of liquefied natural gas, is the temperature difference between the outlet and inlet of liquefied natural gas. a and b are both constants and are related to the temperature of liquefied natural gas, the temperature of natural gas, the density and salinity of seawater, etc. is the maximum volume flow rate of the vaporizer, is the minimum volume flow rate of the vaporizer.

[0091] On the other hand, before adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters, the method further includes:

[0092] Determine the liquid level conservation relationship of the storage tank, which is:

[0093] ;

[0094] Among them, the calculation relationship of the input volume flow rate of the kth storage tank at time t is:

[0095] ;

[0096] The calculation formula for the output volume flow rate of the kth storage tank at time t is:

[0097] ;

[0098] The liquid level constraint of the tank is:

[0099] ;

[0100] in, is the liquid level of the kth tank at time t, is the input volume flow rate of the kth tank at time t, is the output volume flow rate of the kth tank at time t, is the cross-sectional area of the kth tank, is the liquid level of the kth tank at time t-1, is the volume flow rate unloaded from the ship to the k-th storage tank at time t, is the liquefied natural gas returned from each pipeline to the k-th storage tank at time t, is the pumping volume of the lth low-pressure pump of the kth storage tank at time t, is the boil-off gas in the k-th tank at time t, is the minimum liquid level of the tank, is the maximum liquid level of the tank;

[0101] Determine the liquid level conservation relationship of the recondenser, where the liquid level conservation relationship of the recondenser includes:

[0102] ;

[0103] The liquid level constraint of the recondenser is:

[0104] ;

[0105] in, is the liquid level of the recondenser at time t, is the cross-sectional area of the recondenser, is the liquid level of the recondenser at time t-1, is the minimum liquid level of the recondenser, is the maximum liquid level of the recondenser;

[0106] Adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters includes:

[0107] The initial operating parameters are adjusted based on the conservation relationship of the output volume flow rate, the conservation relationship of the liquid level of the storage tank, and the conservation relationship of the liquid level of the recondenser among the initial operating parameters.

[0108] To solve the above technical problems, the present invention further provides an LNG receiving station pipeline network scheduling device based on two-stage optimization, comprising:

[0109] memory for storing computer programs;

[0110] The processor is configured to implement the steps of the above-mentioned LNG receiving station pipeline network scheduling method based on two-stage optimization when executing the computer program.

[0111] The present application provides a method and apparatus for dispatching a pipeline network of an LNG receiving station based on two-stage optimization, which relates to the field of dispatching control. The method and apparatus include adjusting the initial operating parameters of each device in the LNG receiving station based on the constraint relationship between the initial operating parameters. When the initial operating parameters satisfy the energy consumption objective function and reach the minimum value and the value of the initial operating parameters is within the corresponding operating parameter range, the initial operating parameters are determined to be the operating parameters to be corrected; the operating parameters to be corrected are input into the correction model to obtain the dispatching operating parameters; and the various devices in the LNG receiving station are controlled based on the dispatching operating parameters. The adjustment of the operating parameters is determined to be completed when the energy consumption is the lowest. The value range of the parameters during the adjustment process is normal, and the constraint relationship between the parameters is taken into account to avoid the obtained operating parameters not meeting the actual requirements. The adjusted parameters need to be corrected through the correction model before they can control the liquefied natural gas, and the parameters of the liquefied natural gas station are ultimately controlled more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0112] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the prior art and the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0113] Figure 1 A flowchart of a LNG receiving station pipeline network scheduling method based on double-stage optimization provided by the present invention;

[0114] Figure 2 A flow chart for constructing the correction model provided by the present invention;

[0115] Figure 3 A schematic diagram of a scheduling operation parameter provided by the present invention;

[0116] Figure 4 A schematic structural diagram of a pipeline network scheduling device for an LNG receiving station based on double-stage optimization provided by the present invention. DETAILED DESCRIPTION

[0117] The core of this invention is to provide a method and apparatus for dispatching an LNG receiving station pipeline network based on dual-stage optimization. This method determines the end of operating parameter adjustment when energy consumption is minimized. During the adjustment process, the parameter values are within a normal range, and the constraints between the parameters are considered to avoid the resulting operating parameters from not meeting actual requirements. The adjusted parameters must be calibrated using a calibration model before controlling LNG, ultimately achieving more accurate parameter control of the LNG station.

[0118] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0119] Figure 1 A flowchart of a pipeline network scheduling method for an LNG receiving station based on two-stage optimization provided by the present invention is provided. The pipeline network scheduling method for an LNG receiving station based on two-stage optimization is applied to a processor. The equipment in the LNG receiving station includes a storage tank, a recondenser, a high-pressure pump, a low-pressure pump, a seawater pump, a vaporizer, and a compressor. The input end of the low-pressure pump serves as the output end of the storage tank, the evaporation end of the storage tank is connected to the input end of the compressor, the output end of the compressor is connected to the first input end of the recondenser, the output end of the low-pressure pump is respectively connected to the input end of the high-pressure pump and the second input end of the recondenser, the output end of the recondenser is connected to the input end of the high-pressure pump, the output end of the high-pressure pump is connected to the liquid natural gas input end of the vaporizer, and the output end of the seawater pump is connected to the seawater input end of the vaporizer;

[0120] The LNG receiving station pipeline network scheduling method based on two-level optimization includes:

[0121] S11: constructing initial operating parameters for each device in the LNG receiving station, including operating load and output;

[0122] The initial operating parameters constitute the initial scheduling plan, including the low pressure pump start and stop variables , high pressure pump start and stop variables , seawater pump start and stop variables , carburetor start-stop variable , the fraction of time the compressor is running in the entire compressor operation cycle , the output of each low-pressure pump , the amount pumped out by each seawater pump , the amount pumped out by each carburetor .

[0123] In addition, some initialization coefficients need to be set, such as the density of liquid natural gas, the upper and lower limits of the tank liquid level and pressure indicators, the upper and lower limits of the low-pressure pump's pumping volume, the maximum number of low-pressure pumps enabled, the maximum daily volatility of liquid natural gas in the tank, the compressor load level, the upper and lower limits of the recondenser's liquid level and pressure indicators, the upper and lower limits of the high-pressure pump's pumping volume, the maximum number of high-pressure pumps enabled, the upper and lower limits of the seawater pump's pumping volume, the maximum number of seawater pumps enabled, and the maximum number of compressors enabled.

[0124] S12: Construct an energy consumption target function, the value of which is positively correlated with the energy consumption of each device;

[0125] S13: adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters, and determining the initial operating parameters as the operating parameters to be corrected when the initial operating parameters satisfy the energy consumption objective function and reach the minimum value and the values of the initial operating parameters are within the corresponding operating parameter range;

[0126] To improve energy conservation, an energy consumption objective function was constructed. When the energy consumption objective function reaches its minimum value, the energy consumption of the entire LNG station is lowest. However, initial operating parameters cannot be arbitrarily adjusted to reduce energy consumption. This is because the flow direction of LNG affects the initial operating parameters. Operating parameters must remain within their corresponding parameter ranges. For example, the pump output must not exceed the maximum value, nor fall below the minimum value.

[0127] It should also be noted that the pressure of the low-pressure pump of this application is lower than that of the high-pressure pump. The settings of low pressure and high pressure can be set according to actual needs, and this application does not make too many restrictions here.

[0128] S14: Inputting the operating parameters to be corrected into the correction model to obtain the scheduling operating parameters output by the correction model after correcting the operating parameters to be corrected;

[0129] Figure 2 A flow chart for constructing the correction model provided by the present invention;

[0130] First, a dataset is collected, including real-time data sources, historical databases, and environmental data. Then, supervised fine-tuning is performed. By annotating structured data such as LNG terminal-specific equipment parameters, operation logs, and safety procedures, the pre-trained model is adjusted to adapt its parameters to specific scenarios, such as tank pressure control and compressor handling processes. Next, the preliminary scheduling plan generated by the multi-objective optimization module is used as a reference, and the current status of equipment is collected in real time to provide a basis for subsequent evaluation. Finally, the preliminary scheduling plan is input into the calibration model. The calibration model adjusts some equipment selections in the initial plan based on parameters such as the utilization level of each equipment under current operating conditions to avoid equipment fatigue and efficiency losses, thereby optimizing the operation and management of the LNG terminal. The aforementioned real-time data sources include pressure / temperature / flow sensors, valve status, and tank liquid levels. The historical database contains equipment start and stop records, fault logs, energy consumption data, and maintenance cycles. Environmental data includes seawater temperature and atmospheric pressure.

[0131] Figure 3 A schematic diagram of a scheduling operation parameter provided by the present invention;

[0132] S15: Control each device in the LNG receiving terminal based on the scheduling operation parameters.

[0133] The parameters corrected by the correction module can be combined with historical operations, such as how the user adjusted the scheduling plan after obtaining it in history, and then the correction model is trained based on this, without the need for manual correction by the user. The corrected parameters to be operated can be used as scheduling parameters, and the scheduling parameters can directly control the storage tank, recondenser, high-pressure pump, low-pressure pump, seawater pump and compressor.

[0134] The present application provides a method for dispatching a pipeline network of an LNG receiving station based on two-stage optimization, which relates to the field of dispatching control, including adjusting the initial operating parameters of each device in the LNG receiving station based on the constraint relationship between the initial operating parameters, determining the initial operating parameters as the operating parameters to be corrected when the initial operating parameters meet the energy consumption objective function to reach the minimum value and the values of the initial operating parameters are within the corresponding operating parameter range; inputting the operating parameters to be corrected into the correction model to obtain the dispatching operating parameters; and controlling each device in the LNG receiving station based on the dispatching operating parameters. The adjustment of the operating parameters is determined to be completed when the energy consumption is lowest, the value range of the parameters during the adjustment process is normal, and the constraint relationship between the parameters is taken into account to avoid the obtained operating parameters not meeting the actual needs. The adjusted parameters need to be corrected through the correction model before they can control the liquefied natural gas, and the parameters of the liquefied natural gas station are finally controlled more accurately.

[0135] Based on the above embodiment:

[0136] In some embodiments, constructing an energy consumption objective function includes:

[0137] Construct the energy consumption objective function. The expression of the energy consumption objective function is:

[0138] ;

[0139] in, is the minimum energy consumption of the LNG receiving station at time t, is the energy consumption of all low-pressure pumps at time t, is the energy consumption of all compressors at time t, is the energy consumption of all high-pressure pumps at time t, is the energy consumption of all seawater pumps at time t, and T is the maximum time.

[0140] The energy consumption of the LNG receiving station is mainly generated by the operation of the low-pressure pump, compressor, high-pressure pump and seawater pump. Therefore, the energy consumption of the LNG receiving station can be minimized only when the total operating energy consumption of these four devices is minimized.

[0141] In some embodiments, constructing an energy consumption objective function includes:

[0142] Under the condition that the operating state constraints of the low-pressure pump are met, the energy consumption of each low-pressure pump is determined. The expression of the energy consumption of each low-pressure pump is:

[0143] ;

[0144] The expression of the low-pressure pump operating state constraint is:

[0145] ;

[0146] in, is the energy consumption of the lth low-pressure pump in the kth storage tank at time t, is the pumping volume of the lth low-pressure pump in the kth storage tank at time t, is the maximum power consumption of the low-pressure pump, is the maximum volume flow of the low-pressure pump, is the minimum volume flow rate of the low-pressure pump;

[0147] Under the condition that the number of low-pressure pumps started is constrained, the energy consumption of all low-pressure pumps is determined according to the energy consumption of each low-pressure pump. The energy consumption of all low-pressure pumps is expressed as follows:

[0148] ;

[0149] The expression for the starting quantity constraint of the low-pressure pump is:

[0150] ;

[0151] in, It is a binary variable. When the value is 1, it means that the l-th low-pressure pump in the k-th storage tank is enabled at time t. K is the total number of storage tanks, and L is the total number of low-pressure pumps in the storage tank. is the number of low-pressure pumps started in the k-th storage tank at time t, The maximum number of low-pressure pumps enabled.

[0152] Each storage tank has multiple low-pressure pumps. The energy consumption of all low-pressure pumps is composed of the energy consumption of each low-pressure pump in the activated state. The energy consumption of each low-pressure pump in the activated state is positively correlated with its own pumping volume. When the low-pressure pump is running, the pumping volume must be between the maximum volume flow rate and the minimum volume flow rate. The total number of low-pressure pumps in the activated state will not exceed the maximum number of low-pressure pumps that can be activated. For example, if there are 3 low-pressure pumps in total, the maximum number of activations can only be a non-negative integer not greater than 3. All values in this application are integers.

[0153] In some embodiments, constructing an energy consumption objective function includes:

[0154] Under the condition that the operating state constraints of the compressor are met, the energy consumption of each compressor is determined. The expression of the energy consumption of each compressor is:

[0155] ;

[0156] The operating state constraint expression of the compressor is:

[0157] ;

[0158] in, is the energy consumption of the nth compressor at time t, is the energy consumption of the compressor with load level s, is the fraction of time that the nth compressor operates at load level s at time t, which accounts for the entire compressor operation cycle, where S is the maximum load level of the compressor;

[0159] The energy consumption of all compressors is determined based on the energy consumption of each compressor. The energy consumption of all compressors is expressed as:

[0160] ;

[0161] Where N is the total number of compressors.

[0162] The energy consumption of all compressors is determined by the sum of the energy consumption of each compressor in operation. The energy consumption of each compressor is related to the load level of the compressor, which is an integer. The time fraction needs to be limited to 1 because there is no case where the time fraction exceeds 1.

[0163] In some embodiments, constructing an energy consumption objective function includes:

[0164] Determine the number of high-pressure pumps that are turned on. The expression for the number of high-pressure pumps that are turned on is:

[0165] ;

[0166] Determine the energy consumption of each high-pressure pump. The expression for the energy consumption of each high-pressure pump is:

[0167] ;

[0168] in, It is a binary variable. When it is 1, it means that the h-th high-pressure pump is enabled at time t. is the number of high-pressure pumps started at time t, is the energy consumption of the h-th high-pressure pump at time t, is the pumping volume of the hth high-pressure pump at time t, is the maximum power consumption of the high-pressure pump, is the maximum volume flow of the high-pressure pump, and H is the total number of high-pressure pumps;

[0169] Under the conditions of satisfying the operating state constraints of the high-pressure pumps and the startup quantity constraints of the high-pressure pumps, the energy consumption of all high-pressure pumps is determined according to the energy consumption of each high-pressure pump. The energy consumption expression of all high-pressure pumps is:

[0170] ;

[0171] The expression of the operating state constraint of the high-pressure pump is:

[0172] ;

[0173] The expression for the startup quantity constraint of the high-pressure pump is:

[0174] ;

[0175] in, The BHPN high-pressure pump starts at time t, is the energy consumption of the BHPN high-pressure pump at time t, is the minimum volume flow rate of the high-pressure pump, is the maximum number of high-pressure pumps to be started, and a total of BHPN high-pressure pumps are started at time t.

[0176] The energy consumption of all high-pressure pumps is composed of the energy consumption of each high-pressure pump in the active state. The energy consumption of each high-pressure pump in the active state is positively correlated with its own pumping capacity. When the high-pressure pump is running, the pumping capacity must be between the maximum volume flow rate and the minimum volume flow rate. The total number of high-pressure pumps in the active state will not exceed the maximum number of high-pressure pumps that can be activated. For example, if there are 3 high-pressure pumps in total, the maximum number of activations can only be a non-negative integer not greater than 3. All values in this application are integers.

[0177] In some embodiments, constructing an energy consumption objective function includes:

[0178] Under the condition that the operation constraints of the seawater pump are met, the energy consumption of each seawater pump is determined. The expression of the energy consumption of each seawater pump is:

[0179] ;

[0180] The expression of the operating constraint of the seawater pump is:

[0181] ;

[0182] The energy consumption of all seawater pumps is determined based on the energy consumption of each seawater pump. The energy consumption of all seawater pumps is expressed as follows:

[0183] ;

[0184] in, is the energy consumption of the wth seawater pump at time t, is the pumping capacity of the wth seawater pump at time t, is the maximum energy consumption of the seawater pump, is the maximum volume flow rate of the seawater pump, is the minimum volume flow rate of the seawater pump, It is a binary variable. When the value is 1, it means that the wth seawater pump is activated at time t, and W is the total number of seawater pumps.

[0185] Each storage tank has multiple seawater pumps. The energy consumption of all seawater pumps is composed of the energy consumption of each seawater pump in the startup state. The energy consumption of each seawater pump in the startup state is positively correlated with its own pumping capacity. When the seawater pump is running, the pumping capacity must be between the maximum volume flow rate and the minimum volume flow rate. The total number of seawater pumps in the startup state will not exceed the maximum number of seawater pumps that can be activated. For example, if there are 3 seawater pumps in total, the maximum startup number can only be a non-negative integer not greater than 3. All values in this application are integers.

[0186] In some embodiments, before adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters, the method further includes:

[0187] Determine the conservation relationship of the output volume flow rate of the storage tank, high-pressure pump, compressor, recondenser, and vaporizer. The conservation relationship of the output volume flow rate includes:

[0188] The conservation relationship of the volume flow rate of the tank output is expressed as follows:

[0189] ;

[0190] in, is the volume flow rate of all storage tanks output at time t, is the volume flow directly input into the high-pressure pipe network at time t, is the volume flow rate added to the recondenser at time t, is the amount input to the tank truck filling area at time t, It is a binary variable. When it is 1, it means that the l-th low-pressure pump in the k-th storage tank is enabled at time t. is the pumping volume of the lth low-pressure pump of the kth storage tank at time t, K is the total number of storage tanks, and L is the total number of low-pressure pumps in the storage tank;

[0191] The conservation relationship of boil-off gas in a storage tank is expressed as follows:

[0192] ;

[0193] in, is the volume flow rate of all compressors at time t, is the volume flow rate of the nth compressor at time t, is the volume flow rate of boil-off gas from all storage tanks at time t, is the volume flow rate of boil-off gas from the kth tank at time t;

[0194] The conservation relationship of the high-pressure pump output volume flow rate is expressed as follows:

[0195] ;

[0196] in, is the volume flow rate output by all high-pressure pumps at time t, is the amount input from the recondenser at time t, The BHPN high-pressure pump starts at time t, is the pumping volume of the BHPN high-pressure pump at time t, The hth high-pressure pump starts at time t, is the maximum volume flow of the high-pressure pump, and BHPN high-pressure pumps are started at time t;

[0197] The conservation relationship of the recondenser output volume flow rate is expressed as follows:

[0198] ;

[0199] The conservation relationship of the compressor output volume flow rate is expressed as follows:

[0200] ;

[0201] in, is the volume flow rate of the carburetor output at time t, It is a binary variable. When it is 1, it means that the oth carburetor is started at time t. is the output volume flow rate of the oth vaporizer at time t, and O is the total number of vaporizers;

[0202] The conservation relationship of the volume flow rate of the seawater pump is expressed as follows:

[0203] ;

[0204] in, is the volume flow rate of seawater required by the vaporizer, is the seawater heat required by the evaporator at time t, is the specific heat capacity of seawater, is the density of seawater, is the temperature difference between the outlet and inlet of liquefied natural gas at time t, It is a binary variable. When the value is 1, it means that the wth seawater pump is activated at time t. is the volume flow rate pumped out by the wth seawater pump at time t, and W is the total number of seawater pumps;

[0205] Adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters includes:

[0206] The initial operating parameters are adjusted based on the conservation relationship of the output volume flow rate between the initial operating parameters.

[0207] Conservation relationship of volume flow rate of storage tank outflow: the volume flow rate of all storage tank outflows is equal to the volume flow rate directly input into the high-pressure pipeline network, the volume flow rate replenished into the recondenser and the amount input into the tank truck filling area, that is, the pumping volume of all low-pressure pumps.

[0208] Conservation of boil-off gas from storage tanks: The compressor can transfer all boil-off gas generated by the storage tank in a timely manner.

[0209] Conservation relationship of high-pressure pump output volume flow rate: Indicates the energy consumption of the last high-pressure pump started, The total amount of energy delivered by the high-pressure pump to the vaporizer is the sum of the amount delivered from the recondenser and the amount delivered directly from the low-pressure pump.

[0210] The conservation relationship of the recondenser output volume flow rate: the output of the recondenser is equal to the amount of evaporated gas input to the recondenser plus the amount of low-pressure pump input to the recondenser.

[0211] Conservation relationship of the volume flow rate of seawater pump output: comply with the relationship between the specific heat capacity of seawater and the required heat, and all the heat is provided by seawater.

[0212] In some embodiments, the calculation relationship for the volume flow rate of boil-off gas from the kth storage tank at time t is:

[0213] ;

[0214] The calculation relationship of the volume flow of the nth compressor at time t is:

[0215] ;

[0216] The calculation formula for the volume flow of the nth compressor at time t under load level s is:

[0217] ;

[0218] in, is the maximum daily volatility of the storage tank, is the liquid level of the kth tank at time t, is the cross-sectional area of the kth tank, N is the total number of compressors, is the volume flow of the nth compressor at time t under load level s, is the fraction of the time that the nth compressor operates at load level s at time t in the entire compressor operation cycle, is the load fraction corresponding to load level s, is the volume flow of the compressor at maximum load;

[0219] The calculation formula for the seawater heat required by the vaporizer at time t is:

[0220] ;

[0221] The calculation formula for the seawater heat required by the oth vaporizer at time t is:

[0222] ;

[0223] The expression of the operating constraints of the vaporizer is;

[0224] ;

[0225] in, is the seawater heat required by the oth evaporator at time t, is the density of liquefied natural gas, is the temperature difference between the outlet and inlet of liquefied natural gas. a and b are both constants and are related to the temperature of liquefied natural gas, the temperature of natural gas, the density and salinity of seawater, etc. is the maximum volume flow rate of the vaporizer, is the minimum volume flow rate of the vaporizer.

[0226] In some embodiments, before adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters, the method further includes:

[0227] Determine the liquid level conservation relationship of the storage tank. The liquid level conservation relationship of the storage tank is:

[0228] ;

[0229] Among them, the calculation relationship of the input volume flow rate of the kth storage tank at time t is:

[0230] ;

[0231] The calculation formula for the output volume flow rate of the kth storage tank at time t is:

[0232] ;

[0233] The liquid level constraint of the tank is:

[0234] ;

[0235] in, is the liquid level of the kth tank at time t, is the input volume flow rate of the kth tank at time t, is the output volume flow rate of the kth tank at time t, is the cross-sectional area of the kth tank, is the liquid level of the kth tank at time t-1, is the volume flow rate unloaded from the ship to the k-th storage tank at time t, is the liquefied natural gas returned from each pipeline to the k-th storage tank at time t, is the pumping volume of the lth low-pressure pump of the kth storage tank at time t, is the boil-off gas in the k-th tank at time t, is the minimum liquid level of the tank, is the maximum liquid level of the tank;

[0236] Determine the level conservation relationship of the recondenser, which includes:

[0237] ;

[0238] The liquid level constraint of the recondenser is:

[0239] ;

[0240] in, is the liquid level of the recondenser at time t, is the cross-sectional area of the recondenser, is the liquid level of the recondenser at time t-1, is the minimum liquid level of the recondenser, is the maximum liquid level of the recondenser;

[0241] Adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters includes:

[0242] The initial operating parameters are adjusted based on the conservation relationship among the external volume flow rate, the liquid level of the storage tank, and the liquid level of the recondenser.

[0243] The liquid level in a tank is affected by the volume flow rate out of the tank and the boil-off gas from the tank, and is related to the cross-sectional area of the tank itself.

[0244] During the operation of the LNG receiving station, the liquid level in the recondenser remains basically unchanged.

[0245] This application explains the operation process of this application with specific examples:

[0246] Take 4 storage tanks, each of which has 4 low-pressure pumps, 1 recondenser, 2 compressors, 6 high-pressure pumps, 7 vaporizers, and 6 seawater pumps as an example.

[0247] Step 1: Initialize scheduling task parameters;

[0248] Combined with the specific example, assuming that the scheduling target is 800m 3 The scheduling cycle of LNG is 1h.

[0249] The density of liquid natural gas is 430m 3 / kg;

[0250] The upper and lower limits of the tank liquid level indicator are 34.545m and 2.4m respectively;

[0251] The upper and lower limits of low-pressure pump are 400m 3 / h and 50m 3 / h;

[0252] The maximum number of low-pressure pumps that can be used is 3 per tank;

[0253] The maximum daily volatility is 0.05%;

[0254] The compressor load level is [50%, 75%, 100%];

[0255] The upper and lower limits of the recondenser liquid level are 80m and 44m respectively;

[0256] The upper and lower limits of the recondenser pressure are 0.9 MPaG and 1.4 MPaG respectively;

[0257] The upper and lower limits of the high-pressure pump are 407m respectively 3 / h and 50m 3 / h;

[0258] The maximum number of high-pressure pumps that can be activated is 6;

[0259] The upper and lower limits of seawater pump are 7300m 3 / h and 100m 3 / h;

[0260] The maximum number of seawater pumps that can be used is 6;

[0261] The maximum number of vaporizers that can be used is 7;

[0262] The upper and lower limits of the volume flow rate of liquid natural gas exported from the vaporizer are 1095m 3 / h and 100m 3 / h;

[0263] Step 2: Set the initial scheduling conditions and PSO parameters;

[0264] In this example, the initial liquid level of the tank is 22m, the initial liquid level of the recondenser is 60m, and the initial state of the equipment is generally stopped. The population size of the PSO parameter is 100, the number of evaluations is 500, and the termination condition is reaching the maximum number of evaluations and setting the weight coefficient to 0.7.

[0265] Step 3: Call the multi-objective optimization program;

[0266] In this example, the initial scheduling solution obtained by calling the multi-objective optimization program is:

[0267] The startup array of the low-pressure pump is [1,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0], where 1 is on and 0 is off. The flow array is [300,0,250,300,0,0,0,0,0,0,0,0,0,0,0,0];

[0268] The startup array of the high-pressure pump is [1,1,0,0,0,0], 1 is on, 0 is off. The flow array is [407,393,0,0,0,0];

[0269] The operating load array of the compressor is [50%, 75%], and the operating ratio is [1 / 3, 2 / 3]

[0270] The seawater pump startup array is [1,0,0,0,0,0], 1 for on, 0 for off. The seawater flow array is [6000,0,0,0,0,0];

[0271] The vaporizer startup array is [1,0,0,0,0,0,0], and the LNG flow array is [800,0,0,0,0,0,0];

[0272] Step 4: Import the initial scheduling plan and real-time working conditions into the large model;

[0273] The final solution obtained by the large model is:

[0274] The startup array of the low-pressure pump is [1,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0], and the flow array is [300,0,250,300,0,0,0,0,0,0,0,0,0,0,0,0];

[0275] The startup array of the high-pressure pump is [0,1,0,1,0,0], and the flow array is [0,393,0,407,0,0];

[0276] The operating load array of the compressor is [50%, 75%], and the operating ratio is [1 / 3, 2 / 3];

[0277] The seawater pump startup array is [0,0,1,0,0,0], and the seawater flow array is [0,0,6000,0,0,0];

[0278] The vaporizer startup array is [1,0,0,0,0,0,0], and the LNG flow array is [800,0,0,0,0,0,0];

[0279] Reason for modification: It was detected that the high-pressure pump A and the seawater pump A had been running for a long time. In order to extend the life of the equipment and improve efficiency, they were replaced with high-pressure pump D and seawater pump C.

[0280] Step 5: Implement the final plan.

[0281] Figure 4 This is a schematic structural diagram of a LNG receiving station pipeline network scheduling device based on two-stage optimization provided by the present invention. The LNG receiving station pipeline network scheduling device based on two-stage optimization includes:

[0282] Memory 21, for storing computer programs;

[0283] The processor 22 is configured to implement the steps of the above-mentioned LNG receiving station pipeline network scheduling method based on two-stage optimization when executing the computer program.

[0284] For an introduction to the LNG receiving station pipeline scheduling device based on two-stage optimization provided in this application, please refer to the above embodiment and will not be repeated here.

[0285] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only 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 "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0286] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0287] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for dispatching a pipeline network at an LNG receiving station based on dual-stage optimization, characterized in that: Applied to the processor, the equipment in the LNG receiving station includes a storage tank, a recondenser, a high-pressure pump, a low-pressure pump, a seawater pump, a vaporizer and a compressor, the input end of the low-pressure pump serves as the output end of the storage tank, the evaporation end of the storage tank is connected to the input end of the compressor, the output end of the compressor is connected to the first input end of the recondenser, the output end of the low-pressure pump is connected to the input end of the high-pressure pump and the second input end of the recondenser respectively, the output end of the recondenser is connected to the input end of the high-pressure pump, the output end of the high-pressure pump is connected to the liquefied natural gas input end of the vaporizer, and the output end of the seawater pump is connected to the seawater input end of the vaporizer; The LNG receiving station pipeline network scheduling method based on two-level optimization includes: Establishing initial operating parameters for each device in the LNG receiving station, wherein the initial operating parameters include operating load and output; Constructing an energy consumption target function, wherein a value of the energy consumption target function is positively correlated with the energy consumption of each of the devices; Adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters, and determining the initial operating parameters as the operating parameters to be corrected when the initial operating parameters satisfy the energy consumption objective function to reach a minimum value and the values of the initial operating parameters are within the corresponding operating parameter ranges; Inputting the operating parameters to be corrected into a correction model to obtain scheduling operating parameters output by the correction model after correcting the operating parameters to be corrected; Each device in the LNG receiving station is controlled based on the scheduling operation parameters.

2. The LNG receiving station pipeline network scheduling method based on double-stage optimization according to claim 1, characterized in that: Construct an energy consumption objective function, including: Construct an energy consumption objective function, the expression of which is: ； in, is the minimum energy consumption of the LNG receiving station at time t, is the energy consumption of all low-pressure pumps at time t, is the energy consumption of all compressors at time t, is the energy consumption of all high-pressure pumps at time t, is the energy consumption of all seawater pumps at time t, and T is the maximum time.

3. The LNG receiving station pipeline network scheduling method based on dual-stage optimization according to claim 2, characterized in that: Construct an energy consumption objective function, including: Under the condition that the operating state constraints of the low-pressure pumps are satisfied, the energy consumption of each low-pressure pump is determined. The energy consumption of each low-pressure pump is expressed as follows: ； The expression of the low-pressure pump operating state constraint is: ； in, is the energy consumption of the lth low-pressure pump in the kth storage tank at time t, is the pumping volume of the lth low-pressure pump in the kth storage tank at time t, is the maximum power consumption of the low-pressure pump, is the maximum volume flow of the low-pressure pump, is the minimum volume flow rate of the low-pressure pump; Under the condition that the startup quantity constraint of the low-pressure pumps is satisfied, the energy consumption of all low-pressure pumps is determined according to the energy consumption of each low-pressure pump. The energy consumption of all low-pressure pumps is expressed as follows: ； The expression for the startup quantity constraint of the low-pressure pump is: ； in, It is a binary variable. When the value is 1, it means that the l-th low-pressure pump in the k-th storage tank is enabled at time t. K is the total number of storage tanks, and L is the total number of low-pressure pumps in the storage tank. is the number of low-pressure pumps started in the k-th storage tank at time t, The maximum number of low-pressure pumps enabled.

4. The LNG receiving station pipeline network scheduling method based on dual-stage optimization according to claim 2, characterized in that: Construct an energy consumption objective function, including: Under the condition that the operating state constraints of the compressor are met, the energy consumption of each compressor is determined. The expression of the energy consumption of each compressor is: ； The operating state constraint expression of the compressor is: ； in, is the energy consumption of the nth compressor at time t, is the energy consumption of the compressor with load level s, is the fraction of time that the nth compressor operates at load level s at time t, which accounts for the entire compressor operation cycle, where S is the maximum load level of the compressor; The energy consumption of all compressors is determined according to the energy consumption of each compressor. The energy consumption of all compressors is expressed as follows: ； Where N is the total number of compressors.

5. The LNG receiving station pipeline network scheduling method based on dual-stage optimization according to claim 2, characterized in that: Construct an energy consumption objective function, including: The number of high-pressure pumps that are turned on is determined. The expression for the number of high-pressure pumps that are turned on is: ； The energy consumption of each high-pressure pump is determined. The energy consumption of each high-pressure pump is expressed as follows: ； in, It is a binary variable. When it is 1, it means that the h-th high-pressure pump is enabled at time t. is the number of high-pressure pumps started at time t, is the energy consumption of the h-th high-pressure pump at time t, is the pumping volume of the hth high-pressure pump at time t, is the maximum power consumption of the high-pressure pump, is the maximum volume flow of the high-pressure pump, and H is the total number of high-pressure pumps; Under the condition that the operating state constraint of the high-pressure pump and the startup quantity constraint of the high-pressure pump are satisfied, the energy consumption of all high-pressure pumps is determined according to the energy consumption of each high-pressure pump. The energy consumption of all high-pressure pumps is expressed as follows: ； The expression of the operating state constraint of the high-pressure pump is: ； The expression for the startup quantity constraint of the high-pressure pump is: ； in, The BHPN high-pressure pump starts at time t, is the energy consumption of the BHPN high-pressure pump at time t, is the minimum volume flow rate of the high-pressure pump, is the maximum number of high-pressure pumps to be started, and a total of BHPN high-pressure pumps are started at time t.

6. The LNG receiving station pipeline network scheduling method based on dual-stage optimization according to claim 2, characterized in that: Construct an energy consumption objective function, including: Under the condition that the operation constraints of the seawater pump are met, the energy consumption of each seawater pump is determined. The expression of the energy consumption of each seawater pump is: ； The expression of the operation constraint of the seawater pump is: ； The energy consumption of all seawater pumps is determined based on the energy consumption of each seawater pump. The energy consumption of all seawater pumps is expressed as follows: ； in, is the energy consumption of the wth seawater pump at time t, is the pumping capacity of the wth seawater pump at time t, is the maximum energy consumption of the seawater pump, is the maximum volume flow rate of the seawater pump, is the minimum volume flow rate of the seawater pump, It is a binary variable. When the value is 1, it means that the wth seawater pump is activated at time t, and W is the total number of seawater pumps.

7. The LNG receiving station pipeline network scheduling method based on double-stage optimization according to any one of claims 1 to 6, characterized in that: Before adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters, the method further includes: Determine the conservation relationship of the output volume flow of the storage tank, the high-pressure pump, the compressor, the recondenser, and the vaporizer, wherein the conservation relationship of the output volume flow includes: The conservation relationship of the volume flow rate of the tank output is expressed as follows: ； in, is the volume flow rate of all storage tanks output at time t, is the volume flow directly input into the high-pressure pipe network at time t, is the volume flow rate added to the recondenser at time t, is the amount input to the tank truck filling area at time t, It is a binary variable. When it is 1, it means that the l-th low-pressure pump in the k-th storage tank is enabled at time t. is the pumping volume of the lth low-pressure pump of the kth storage tank at time t, K is the total number of storage tanks, and L is the total number of low-pressure pumps in the storage tank; The conservation relationship of boil-off gas in a storage tank is expressed as follows: ； in, is the volume flow rate of all compressors at time t, is the volume flow rate of the nth compressor at time t, is the volume flow rate of boil-off gas from all storage tanks at time t, is the volume flow rate of boil-off gas from the kth tank at time t, and N is the total number of compressors; The conservation relationship of the high-pressure pump output volume flow rate is expressed as follows: ； in, is the volume flow rate output by all high-pressure pumps at time t, is the amount input from the recondenser at time t, The BHPN high-pressure pump starts at time t, is the pumping volume of the BHPN high-pressure pump at time t, The hth high-pressure pump starts at time t, is the maximum volume flow of the high-pressure pump, and BHPN high-pressure pumps are started at time t; The conservation relationship of the recondenser output volume flow rate is expressed as follows: ； The conservation relationship of the compressor output volume flow rate is expressed as follows: ； in, is the volume flow rate of the carburetor output at time t, It is a binary variable. When it is 1, it means that the oth carburetor is started at time t. is the output volume flow rate of the oth vaporizer at time t, and O is the total number of vaporizers; The conservation relationship of the volume flow rate of the seawater pump is expressed as follows: ； in, is the volume flow rate of seawater required by the vaporizer, is the seawater heat required by the evaporator at time t, is the specific heat capacity of seawater, is the density of seawater, is the temperature difference between the outlet and inlet of liquefied natural gas at time t, It is a binary variable. When the value is 1, it means that the wth seawater pump is activated at time t. is the volume flow rate pumped out by the wth seawater pump at time t, and W is the total number of seawater pumps; Adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters includes: The initial operating parameters are adjusted based on a conservation relationship of the output volume flow rate between the initial operating parameters.

8. The LNG receiving station pipeline network scheduling method based on dual-stage optimization according to claim 7, characterized in that: The calculation relationship of the volume flow rate of the boil-off gas of the kth storage tank at time t is: ； The calculation relationship of the volume flow of the nth compressor at time t is: ； The calculation formula for the volume flow of the nth compressor at time t under load level s is: ； in, is the maximum daily volatility of the storage tank, is the liquid level of the kth tank at time t, is the cross-sectional area of the kth tank, N is the total number of compressors, is the volume flow of the nth compressor at time t under load level s, is the fraction of the time that the nth compressor operates at load level s at time t in the entire compressor operation cycle, is the load fraction corresponding to load level s, is the volume flow of the compressor at maximum load; The calculation formula for the seawater heat required by the vaporizer at time t is: ； The calculation formula for the seawater heat required by the oth vaporizer at time t is: ； The expression of the operating constraints of the vaporizer is; ； in, is the seawater heat required by the oth evaporator at time t, is the density of liquefied natural gas, is the temperature difference between the outlet and inlet of liquefied natural gas, a and b are both constants, which are related to the temperature of liquefied natural gas, the temperature of natural gas, the density and salinity of seawater, etc. is the maximum volume flow rate of the vaporizer, is the minimum volume flow rate of the vaporizer.

9. The LNG receiving station pipeline network scheduling method based on dual-stage optimization according to claim 7, characterized in that: Before adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters, the method further includes: Determine the liquid level conservation relationship of the storage tank, which is: ； Among them, the calculation relationship of the input volume flow rate of the kth storage tank at time t is: ； The calculation formula for the output volume flow rate of the kth storage tank at time t is: ； The liquid level constraint of the tank is: ； in, is the liquid level of the kth tank at time t, is the input volume flow rate of the kth tank at time t, is the output volume flow rate of the kth tank at time t, is the cross-sectional area of the kth tank, is the liquid level of the kth tank at time t-1, is the volume flow rate unloaded from the ship to the k-th storage tank at time t, is the liquefied natural gas returned from each pipeline to the k-th storage tank at time t, is the pumping volume of the lth low-pressure pump of the kth storage tank at time t, is the boil-off gas in the k-th tank at time t, is the minimum liquid level of the tank, is the maximum liquid level of the tank; Determine the liquid level conservation relationship of the recondenser, where the liquid level conservation relationship of the recondenser includes: ； The liquid level constraint of the recondenser is: ； in, is the liquid level of the recondenser at time t, is the cross-sectional area of the recondenser, is the liquid level of the recondenser at time t-1, is the minimum liquid level of the recondenser, is the maximum liquid level of the recondenser; Adjusting the initial operating parameters based on the constraint relationship between the initial operating parameters includes: The initial operating parameters are adjusted based on the conservation relationship of the output volume flow rate, the conservation relationship of the liquid level of the storage tank, and the conservation relationship of the liquid level of the recondenser among the initial operating parameters.

10. A LNG receiving station pipeline network scheduling device based on two-stage optimization, characterized in that: include: memory for storing computer programs; A processor is configured to implement the steps of the LNG receiving station pipeline network scheduling method based on two-stage optimization as described in any one of claims 1 to 9 when executing the computer program.

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