Heat exchange-based liquefied BOG (boil-off gas) output prediction method for LNG (liquefied natural gas) storage tank and related device

Abstract

The invention discloses an LNG storage tank liquefied BOG output prediction method based on heat exchange and a related device, and belongs to the technical field of output prediction, and the method comprises the following steps: obtaining heat insulation performance parameters of an LNG storage tank, thermophysical parameters of LNG and structural parameters of the LNG storage tank; constructing an LNG storage tank internal heat exchange dynamic model; the layered temperature gradient of a liquid phase in the LNG storage tank and the layered temperature gradient of a gas phase in the LNG storage tank are obtained, and external surrounding environment parameters of the LNG storage tank are obtained; inputting the stratified temperature gradient of the liquid phase in the LNG storage tank, the stratified temperature gradient of the gas phase in the LNG storage tank and the external surrounding environment parameters of the LNG storage tank into the internal heat exchange dynamic model of the LNG storage tank, predicting the BOG generation rate of each height layer in the LNG storage tank, and calculating the total BOG generation amount of the LNG storage tank according to the BOG generation rate of each height layer in the LNG storage tank. According to the method and the related device, the BOG output of the LNG storage tank can be accurately predicted.

Description

Technical Field

[0001] The invention belongs to the technical field of production prediction, and relates to a method for predicting the production of liquefied BOG in an LNG storage tank based on heat exchange and a related device. Background Art

[0002] During the storage and transportation of LNG (Liquefied Natural Gas) tanks, the LNG inside the LNG tanks will inevitably evaporate and produce BOG (Boil-Off Gas), which is affected by factors such as ambient temperature, tank insulation performance and internal heat exchange. The generation of BOG will not only affect the stability of the internal pressure of the LNG tanks, but also may cause energy loss and even affect the subsequent gasification transportation, reliquefaction recovery and safety management. Therefore, accurately predicting the BOG generation of LNG tanks is of great significance for optimizing the operation of LNG tanks, improving energy utilization and reducing safety risks.

[0003] At present, the prediction methods of BOG generation mainly include empirical formula estimation, pressure change method and mathematical model method based on heat exchange. Among them, the empirical formula estimation method usually performs approximate calculations based on the design parameters and historical operation data of LNG storage tanks, but this method is difficult to consider the influence of different environmental factors and the prediction accuracy is low; the pressure change method calculates the BOG amount by monitoring the rate of change of the internal pressure of the storage tank, but it is easily affected by liquid level changes and fluctuations in operating conditions, and its applicability is limited; the mathematical model method based on heat exchange uses the thermophysical characteristics of the storage tank, external environmental parameters and LNG physical properties to establish a heat exchange calculation model, which improves the prediction accuracy to a certain extent, but the existing methods mostly use a single temperature or static heat balance calculation, which fails to fully consider the temperature stratification inside the storage tank and the influence of dynamic changes in the external environment on the latent heat of vaporization, so the prediction accuracy is poor. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method and related device for predicting the amount of BOG produced by liquefaction of LNG storage tanks based on heat exchange. The method and related device can accurately predict the amount of BOG produced by LNG storage tanks.

[0005] To achieve the above object, the present invention discloses a method for predicting the amount of BOG produced by liquefaction of an LNG storage tank based on heat exchange, comprising: Obtain the insulation performance parameters of the LNG storage tank, the thermal physical parameters of LNG and the structural parameters of the LNG storage tank; Based on the insulation performance parameters of the LNG storage tank, the thermophysical parameters of the LNG and the structural parameters of the LNG storage tank, a dynamic model of heat exchange inside the LNG storage tank is constructed; Obtaining the stratified temperature gradient of the liquid phase in the LNG storage tank and the stratified temperature gradient of the gas phase in the LNG storage tank, and obtaining the external ambient environment parameters of the LNG storage tank; The stratified temperature gradient of the liquid phase in the LNG storage tank, the stratified temperature gradient of the gas phase in the LNG storage tank, and the external ambient environment parameters of the LNG storage tank are input into the internal heat exchange dynamic model of the LNG storage tank to predict the BOG generation rate of each height layer in the LNG storage tank, and the total BOG generation of the LNG storage tank is calculated based on the BOG generation rate of each height layer in the LNG storage tank.

[0006] The further improvement of the heat exchange-based LNG storage tank liquefaction BOG generation prediction method of the present invention is: Furthermore, the thermal insulation performance parameters of the LNG storage tank include the heat flux density of the LNG storage tank wall. The thermal physical parameters of LNG include the latent heat of vaporization of LNG ; The structural parameters of the LNG storage tank include the wall thickness of the LNG storage tank .

[0007] Furthermore, the LNG tank internal heat exchange dynamic model is composed of the LNG tank total heat input equation, the LNG tank wall heat transfer equation, the LNG vaporization mass calculation equation and the LNG temperature change equation.

[0008] Furthermore, the total BOG production of the LNG storage tank is for:

[0009] in, is the number of layers, For the LNG tank BOG generation rate at this altitude.

[0010] Furthermore, the LNG storage tank BOG generation rate at altitude for:

[0011]

[0012] in, is the corrected theoretical vaporization mass of LNG, For the LNG tank Liquid temperature at altitude, For the LNG tank The gas phase temperature at the altitude, is the corrected total heat input, is the heat transferred through the LNG tank wall per unit time, is the adjustment factor, is the latent heat of vaporization of the LNG mixture, It is the average temperature of LNG in the LNG storage tank.

[0013] Furthermore, the corrected total heat input for:

[0014] in, is the experience modifier, for: ; in, is the standard humidity, is the temperature correction coefficient, is the humidity correction factor, is the wind speed correction factor, is the temperature of the surrounding environment outside the LNG storage tank, is the humidity of the surrounding environment outside the LNG storage tank, is the wind speed outside the LNG storage tank, It is the total heat entering the LNG storage tank per unit time.

[0015] Furthermore, the LNG storage tank Liquid temperature at altitude And the LNG tank Gas phase temperature at altitude for:

[0016]

[0017] in, is the initial temperature of the liquid phase in the LNG storage tank, is the initial temperature of the gas phase in the LNG storage tank, is the layer height of the liquid phase, is the layer height of the gas phase, is the stratified temperature gradient of the liquid phase in the LNG storage tank, is the stratified temperature gradient of the gas phase in the LNG storage tank.

[0018] The present invention discloses a heat exchange-based LNG storage tank liquefied BOG production prediction system, comprising: The first acquisition module is used to obtain the insulation performance parameters of the LNG storage tank, the thermal physical parameters of the LNG and the structural parameters of the LNG storage tank; A construction module is used to construct a dynamic model of heat exchange inside the LNG storage tank based on the insulation performance parameters of the LNG storage tank, the thermophysical parameters of the LNG and the structural parameters of the LNG storage tank; The second acquisition module is used to acquire the stratified temperature gradient of the liquid phase in the LNG storage tank and the stratified temperature gradient of the gas phase in the LNG storage tank, and acquire the external ambient environment parameters of the LNG storage tank; The prediction module is used to input the stratified temperature gradient of the liquid phase in the LNG storage tank, the stratified temperature gradient of the gas phase in the LNG storage tank and the external ambient environment parameters of the LNG storage tank into the internal heat exchange dynamic model of the LNG storage tank to predict the total BOG generation of the LNG storage tank.

[0019] The present invention discloses a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for predicting the amount of BOG produced by liquefaction of an LNG storage tank based on heat exchange are implemented.

[0020] The present invention discloses a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for predicting the amount of BOG produced by liquefaction of an LNG storage tank based on heat exchange are implemented.

[0021] The present invention has the following beneficial effects: The heat exchange-based LNG storage tank liquefaction BOG generation prediction method and related devices of the present invention, during specific operation, comprehensively consider the insulation performance parameters of the LNG storage tank, the thermophysical parameters of the LNG storage tank and the structural parameters of the LNG storage tank, and construct a dynamic model of heat exchange inside the LNG storage tank, so that the heat exchange inside the LNG storage tank is more in line with the real environment. At the same time, the stratified temperature gradient of the liquid phase in the LNG storage tank, the stratified temperature gradient of the gas phase in the LNG storage tank and the external ambient environment parameters of the LNG storage tank are input into the dynamic model of heat exchange inside the LNG storage tank to predict the total BOG generation of the LNG storage tank. In which, based on the multi-source data input method, the predicted result can adapt to different climatic conditions and avoid the limitation of single parameter prediction. At the same time, the total BOG generation of the LNG storage tank is predicted based on the stratified temperature gradient to improve the refinement of the prediction and make the prediction result of the total BOG generation more accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings: Figure 1 is a flow chart of the method of the present invention; Figure 2 It is a system structure diagram of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0025] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0026] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0027] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0028] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0031] Embodiment 1 refer to Figure 1 The method for predicting the amount of BOG produced by liquefaction of an LNG storage tank based on heat exchange of the present invention comprises the following steps: 1) Obtain the insulation performance parameters of the LNG storage tank, the thermal physical parameters of LNG and the structural parameters of the LNG storage tank; The insulation performance parameters of the LNG storage tank include the heat flux density of the LNG storage tank wall. , where the heat flux density of the LNG tank wall is measured by a heat flux sensor , , is the thermal conductivity of the insulation layer in the LNG storage tank, is the temperature of the inner wall of the LNG storage tank, is the temperature of the outer wall of the LNG storage tank, is the thickness of the insulation layer in the LNG storage tank.

[0032] The thermophysical parameters of LNG include the latent heat of vaporization of LNG , the latent heat of vaporization of LNG It is measured by an online LNG component analyzer, where: , It is the first The mole fraction of the component, It is the first The latent heat of vaporization of the component.

[0033] The structural parameters of the LNG storage tank include the wall thickness of the LNG storage tank ,in, , is the design pressure inside the LNG tank, is the inner diameter of the LNG storage tank, It is the allowable stress of materials used in LNG storage tanks.

[0034] 2) constructing a dynamic model of heat exchange inside the LNG storage tank based on the insulation performance parameters of the LNG storage tank, the thermophysical parameters of LNG and the structural parameters of the LNG storage tank; It should be noted that the dynamic model of internal heat exchange of the LNG storage tank includes the total heat input equation of the LNG storage tank, the heat transfer equation of the LNG storage tank wall, the LNG vaporization mass calculation equation and the LNG temperature change equation.

[0035] Among them, based on the heat flux density of the LNG tank wall The total heat input equation for the LNG storage tank is constructed as:

[0036] in, is the total heat entering the LNG storage tank per unit time, It is the external surface area of ​​the LNG storage tank.

[0037] Based on the wall thickness of the LNG tank The heat transfer equation of the LNG tank wall is constructed as follows:

[0038] in, is the heat transferred through the LNG tank wall per unit time, It is the thermal conductivity of the material used for the LNG tank wall.

[0039] The LNG temperature variation equation is expressed as:

[0040] in, is the average temperature of LNG in the LNG storage tank, For time, is the mass of LNG in the LNG storage tank, is the specific heat capacity of LNG.

[0041] Based on the latent heat of vaporization of LNG The calculation equation for LNG vaporization mass per unit time is established as follows:

[0042] in, is the theoretical vaporization mass of LNG per unit time, To consider the latent heat of vaporization of LNG after the influence of the current average temperature of LNG, it is specifically:

[0043] in, Standard temperature The latent heat of vaporization of LNG is is the latent heat of vaporization correction factor related to LNG components, which is used to characterize the effect of temperature change on the latent heat of vaporization. The value range is: For standard LNG, i.e. LNG with a methane content > 90%, The value of .

[0044] For LNG rich in ethane / propane, the methane content of LNG is ,but The value of .

[0045] For nitrogen-rich LNG, i.e. LNG with a methane content of <80%, The value of .

[0046] 3) Obtain the stratified temperature gradient of the liquid phase in the LNG storage tank and the stratified temperature gradient of the gas phase in the LNG storage tank, and obtain the external ambient environment parameters of the LNG storage tank; Specifically, the external environmental parameters of the LNG storage tank include the temperature, humidity and wind speed of the external environment of the LNG storage tank. A plurality of temperature sensors are arranged in the vertical direction of the liquid phase and the gas phase inside the LNG storage tank, and the temperature at different heights in the liquid phase inside the LNG storage tank is measured by each temperature sensor. and the temperature at different altitudes in the gas phase , according to the temperature at different heights in the liquid phase inside the LNG storage tank Calculation of stratified temperature gradients of liquid phase in LNG storage tanks ; According to the temperature at different heights in the gas phase inside the LNG storage tank Calculation of stratified temperature gradients in the gas phase of an LNG tank ; Use the ambient temperature and humidity sensor to detect the temperature of the surrounding environment outside the LNG storage tank and humidity , measure the wind speed outside the LNG tank using an anemometer It should be noted that the present invention is based on the preset time interval Perform synchronous data acquisition.

[0047] Stratified temperature gradient of liquid phase in LNG storage tank and the stratified temperature gradient of the gas phase in the LNG storage tank They are:

[0048]

[0049] in, is the vertical distance between adjacent temperature sensors in the liquid phase of the LNG tank, It is the vertical distance between adjacent temperature sensors in the gas phase of the LNG storage tank.

[0050] 4) The obtained liquid phase stratification temperature gradient in the LNG storage tank, the gas phase stratification temperature gradient in the LNG storage tank, and the external ambient environment parameters of the LNG storage tank are input into the internal heat exchange dynamic model of the LNG storage tank to predict the BOG generation rate of each height layer in the LNG storage tank, and the total BOG generation amount of the LNG storage tank is calculated according to the BOG generation rate of each height layer in the LNG storage tank.

[0051] The specific process of step 4) is as follows: 41) Calculate the temperature distribution of each layer in the LNG tank. Liquid temperature at altitude And the LNG tank Gas phase temperature at altitude for:

[0052]

[0053] in, is the initial temperature of the liquid phase in the LNG storage tank, is the initial temperature of the gas phase in the LNG storage tank, is the layer height of the liquid phase, is the stratification height of the gas phase.

[0054] 42) According to the temperature of the surrounding environment outside the LNG storage tank and humidity and the wind speed outside the LNG tank Calculate the corrected total heat input , where the corrected total heat input is for:

[0055] in, is an empirical correction term used to correct the additional heat exchange caused by environmental changes. Specifically, for: ; in, is the standard humidity, is the temperature correction coefficient, Used to characterize the effect of ambient temperature on heat exchange of LNG tanks. is the humidity correction factor, Used to characterize the effect of humidity on heat transfer, is the wind speed correction factor, Used to characterize the effect of wind speed on heat transfer.

[0056] 43) The corrected total heat input As the total heat entering the LNG storage tank per unit time , calculate the temperature change of LNG ; 44) Calculate the corrected theoretical vaporization mass of LNG ,in, ; 45) Calculate the BOG generation rate at different height levels in the LNG tank for:

[0057] in, is the adjustment factor, Affected by the composition of LNG and the operating conditions of LNG storage tanks, specifically: For standard cryogenic tanks, i.e. storage at atmospheric pressure, The value of , suitable for large LNG storage tanks.

[0058] For medium pressure tanks, that is, the pressure range in LNG tanks is ,but The value of , suitable for smaller LNG storage tanks.

[0059] For high pressure storage tanks, that is, the pressure inside the LNG storage tank is greater than 0.5MPa, then The value of .

[0060] 46) Calculate the total BOG generation based on the BOG generation rate at all levels in the LNG tank ,in, is the number of layers.

[0061] Embodiment 2 refer to Figure 2 This embodiment discloses a heat exchange-based LNG storage tank liquefaction BOG production prediction system, including: The first acquisition module is used to obtain the insulation performance parameters of the LNG storage tank, the thermal physical parameters of the LNG and the structural parameters of the LNG storage tank; A construction module is used to construct a dynamic model of heat exchange inside the LNG storage tank based on the insulation performance parameters of the LNG storage tank, the thermophysical parameters of the LNG and the structural parameters of the LNG storage tank; The second acquisition module is used to acquire the stratified temperature gradient of the liquid phase in the LNG storage tank and the stratified temperature gradient of the gas phase in the LNG storage tank, and acquire the external ambient environment parameters of the LNG storage tank; The prediction module is used to input the stratified temperature gradient of the liquid phase in the LNG storage tank, the stratified temperature gradient of the gas phase in the LNG storage tank and the external ambient environment parameters of the LNG storage tank into the internal heat exchange dynamic model of the LNG storage tank, predict the BOG generation rate of each height layer in the LNG storage tank, and calculate the total BOG generation of the LNG storage tank according to the BOG generation rate of each height layer in the LNG storage tank.

[0062] The division of modules in the embodiments of the present invention is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each embodiment of the present invention may be integrated into one processor, or may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0063] Embodiment 3 A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for predicting the amount of BOG generated by liquefaction of an LNG storage tank based on heat exchange are implemented, for example, comprising: obtaining thermal insulation performance parameters of the LNG storage tank, thermophysical parameters of the LNG and structural parameters of the LNG storage tank; constructing a dynamic model of heat exchange inside the LNG storage tank based on the thermal insulation performance parameters of the LNG storage tank, the thermophysical parameters of the LNG and structural parameters of the LNG storage tank; obtaining a stratified temperature gradient of a liquid phase in the LNG storage tank and a stratified temperature gradient of a gas phase in the LNG storage tank, and obtaining parameters of an external surrounding environment of the LNG storage tank; inputting the stratified temperature gradient of the liquid phase in the LNG storage tank, the stratified temperature gradient of the gas phase in the LNG storage tank and the parameters of the external surrounding environment of the LNG storage tank into the dynamic model of heat exchange inside the LNG storage tank, predicting the BOG generation rate of each height layer in the LNG storage tank, and calculating the total BOG generation of the LNG storage tank according to the BOG generation rate of each height layer in the LNG storage tank. The memory may include a memory, such as a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk memory, etc. The processor, network interface, and memory are interconnected through an internal bus, and the internal bus may be an industrial standard architecture bus, a peripheral component interconnection standard bus, an extended industrial standard architecture bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. The memory is used to store programs. Specifically, the program may include a program code, and the program code includes computer operation instructions. The memory may include a memory and a non-volatile memory, and provide instructions and data to the processor.

[0064] Embodiment 4 A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for predicting the amount of BOG produced by liquefaction of an LNG tank based on heat exchange are implemented, including: obtaining the insulation performance parameters of the LNG tank, the thermophysical parameters of the LNG, and the structural parameters of the LNG tank; constructing a dynamic model of heat exchange inside the LNG tank based on the insulation performance parameters of the LNG tank, the thermophysical parameters of the LNG, and the structural parameters of the LNG tank; obtaining the stratified temperature gradient of the liquid phase in the LNG tank and the stratified temperature gradient of the gas phase in the LNG tank, and obtaining the external ambient environment parameters of the LNG tank; inputting the stratified temperature gradient of the liquid phase in the LNG tank, the stratified temperature gradient of the gas phase in the LNG tank, and the external ambient environment parameters of the LNG tank into the dynamic model of heat exchange inside the LNG tank, predicting the BOG generation rate of each height layer in the LNG tank, and calculating the total BOG generation of the LNG tank according to the BOG generation rate of each height layer in the LNG tank. Specifically, the computer-readable storage medium includes, but is not limited to, for example, a volatile memory and / or a non-volatile memory. The volatile memory may include a random access memory (RAM) and / or a cache memory (cache), etc. The non-volatile memory may include a read-only memory (ROM), a hard disk, a flash memory, an optical disk, a magnetic disk, etc.

[0065] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0066] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0067] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0068] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0069] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. The present invention is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The description and examples are to be regarded as exemplary only, and the true scope and spirit of the present invention is indicated by the following claims.

[0070] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0071] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for predicting the amount of BOG produced by liquefaction of LNG storage tanks based on heat exchange, characterized in that: include: Obtain the insulation performance parameters of the LNG storage tank, the thermal physical parameters of LNG and the structural parameters of the LNG storage tank; Based on the insulation performance parameters of the LNG storage tank, the thermophysical parameters of the LNG and the structural parameters of the LNG storage tank, a dynamic model of heat exchange inside the LNG storage tank is constructed; Obtaining the stratified temperature gradient of the liquid phase in the LNG storage tank and the stratified temperature gradient of the gas phase in the LNG storage tank, and obtaining the external ambient environment parameters of the LNG storage tank; The stratified temperature gradient of the liquid phase in the LNG storage tank, the stratified temperature gradient of the gas phase in the LNG storage tank, and the external ambient environment parameters of the LNG storage tank are input into the internal heat exchange dynamic model of the LNG storage tank to predict the BOG generation rate of each height layer in the LNG storage tank, and the total BOG generation of the LNG storage tank is calculated based on the BOG generation rate of each height layer in the LNG storage tank.

2. The method for predicting the amount of BOG produced by liquefaction of an LNG storage tank based on heat exchange according to claim 1, characterized in that: The insulation performance parameters of the LNG storage tank include the heat flux density of the LNG storage tank wall. The thermal physical parameters of LNG include the latent heat of vaporization of LNG ; The structural parameters of the LNG storage tank include the wall thickness of the LNG storage tank .

3. The method for predicting the amount of BOG produced by liquefaction of an LNG storage tank based on heat exchange according to claim 1, characterized in that: The LNG tank internal heat exchange dynamic model is composed of the LNG tank total heat input equation, the LNG tank wall heat transfer equation, the LNG vaporization mass calculation equation and the LNG temperature change equation.

4. The method for predicting the amount of BOG produced by liquefaction of an LNG storage tank based on heat exchange according to claim 1, characterized in that: Total BOG generation of the LNG storage tank for: in, is the number of layers, For the LNG tank BOG generation rate at this altitude.

5. The method for predicting the amount of BOG produced by liquefaction of an LNG storage tank based on heat exchange according to claim 4, characterized in that: The LNG storage tank BOG generation rate at altitude for: in, is the corrected theoretical vaporization mass of LNG, For the LNG tank Liquid temperature at altitude, For the LNG tank The gas phase temperature at the altitude, is the corrected total heat input, is the heat transferred through the LNG tank wall per unit time, is the adjustment factor, is the latent heat of vaporization of the LNG mixture, It is the average temperature of LNG in the LNG storage tank.

6. The method for predicting the amount of BOG produced by liquefaction of an LNG storage tank based on heat exchange according to claim 5, characterized in that: The corrected total heat input for: in, is the experience modifier, for: ； in, is the standard humidity, is the temperature correction coefficient, is the humidity correction factor, is the wind speed correction factor, is the temperature of the surrounding environment outside the LNG storage tank, is the humidity of the surrounding environment outside the LNG storage tank, is the wind speed outside the LNG storage tank, It is the total heat entering the LNG storage tank per unit time.

7. The method for predicting the amount of BOG produced by liquefaction of an LNG storage tank based on heat exchange according to claim 5, characterized in that: The LNG storage tank Liquid temperature at altitude And the LNG tank Gas phase temperature at altitude for: in, is the initial temperature of the liquid phase in the LNG storage tank, is the initial temperature of the gas phase in the LNG storage tank, is the layer height of the liquid phase, is the layer height of the gas phase, is the stratified temperature gradient of the liquid phase in the LNG storage tank, is the stratified temperature gradient of the gas phase in the LNG storage tank.

8. A heat exchange-based LNG tank liquefaction BOG production prediction system, characterized in that: include: The first acquisition module is used to obtain the insulation performance parameters of the LNG storage tank, the thermal physical parameters of the LNG and the structural parameters of the LNG storage tank; A construction module is used to construct a dynamic model of heat exchange inside the LNG storage tank based on the insulation performance parameters of the LNG storage tank, the thermophysical parameters of the LNG and the structural parameters of the LNG storage tank; The second acquisition module is used to acquire the stratified temperature gradient of the liquid phase in the LNG storage tank and the stratified temperature gradient of the gas phase in the LNG storage tank, and acquire the external ambient environment parameters of the LNG storage tank; The prediction module is used to input the stratified temperature gradient of the liquid phase in the LNG storage tank, the stratified temperature gradient of the gas phase in the LNG storage tank and the external ambient environment parameters of the LNG storage tank into the internal heat exchange dynamic model of the LNG storage tank, predict the BOG generation rate of each height layer in the LNG storage tank, and calculate the total BOG generation of the LNG storage tank according to the BOG generation rate of each height layer in the LNG storage tank.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for predicting the amount of BOG produced by liquefaction of an LNG storage tank based on heat exchange as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for predicting the amount of BOG produced by liquefaction of an LNG storage tank based on heat exchange as described in any one of claims 1 to 7 are implemented.

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