A method for rapidly detecting the heat insulation performance of a liquid hydrogen container

Abstract

The present application relates to liquid hydrogen storage and transportation technology field, disclose a kind of liquid hydrogen container heat insulation performance rapid detection method, comprising the following steps: S1, measure liquid hydrogen container specification and initial state parameter in liquid hydrogen container;S2, calculate the initial parameter of liquid hydrogen and hydrogen in liquid hydrogen container;S3, measure the rate of change of state parameter in liquid hydrogen container, and monitor the final state parameter in liquid hydrogen container;S4, calculate the final parameter of liquid hydrogen and hydrogen in liquid hydrogen container;S5, according to the rate of change of state parameter in liquid hydrogen container, calculate the evaporation mass flow rate of liquid hydrogen container gas-liquid interface;S6, calculate the thermodynamic energy change rate of hydrogen and liquid hydrogen in liquid hydrogen container;S7, calculate the total internal energy change of liquid hydrogen container, calculate the total heat transfer of liquid and gas phase of liquid hydrogen container;S8, the total heat transfer of liquid and gas phase of liquid hydrogen container is compared with standard static evaporation rate data, obtains the heat insulation performance of liquid hydrogen container.This detection method has the characteristics of no hydrogen emission, improve detection precision and safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of liquid hydrogen storage and transportation, and particularly relates to a method for rapidly detecting the heat insulation performance of a liquid hydrogen container. BACKGROUND

[0002] With the gradual transformation of global energy structure, hydrogen is considered an important component of future clean energy. Liquid hydrogen has a relatively high mass energy density, which enables it to store more energy and occupy less space when used as a reserve energy source. The storage temperature of liquid hydrogen is extremely low (-253℃), and the latent heat of vaporization is small. Therefore, strict heat insulation treatment must be carried out under ultra-high vacuum conditions to prevent the pressure of the liquid hydrogen container from rising due to evaporation loss. Therefore, it is crucial to ensure the heat insulation performance of the container during the design and use of the liquid hydrogen container.

[0003] The heat insulation performance test of a liquid hydrogen container is a key link to ensure its safety and efficiency. Static evaporation rate is the most intuitive and important technical index parameter for evaluating the heat insulation performance of a liquid hydrogen container. The static evaporation rate of a liquid hydrogen container is calculated by the evaporation flow rate of hydrogen gas after stabilization. For liquid hydrogen medium, this heat insulation performance test method has obvious defects. A large amount of hydrogen gas needs to be discharged during the test, which not only causes resource waste but also may cause a series of safety hazards. On the other hand, the GB / T18443.5-2010 (Vacuum Insulated Cryogenic Equipment Performance Test Method: Static Evaporation Rate Measurement) standard strictly stipulates that the static evaporation rate test is not applicable to liquid hydrogen medium. At present, the evaporation rate test of most liquid hydrogen containers still relies on liquid nitrogen medium. However, due to the differences in physical properties between liquid nitrogen and liquid hydrogen, especially the significant differences in the latent heat of evaporation of liquid nitrogen and the heat exchange characteristics between liquid nitrogen and the container wall and liquid hydrogen, there is a large error in calculating the actual heat insulation performance of the liquid hydrogen container by using the liquid nitrogen medium. Therefore, the above problems make the heat insulation performance test of the liquid hydrogen container complex and challenging.

[0004] In summary, based on the problems existing in the current heat insulation performance test method of the liquid hydrogen container, a new, more efficient and safe heat insulation performance detection method for the liquid hydrogen container is urgently needed. SUMMARY

[0005] In view of the above problems in the prior art, the present application provides a method for rapidly detecting the heat insulation performance of a liquid hydrogen container, which solves the problems of long detection period, high hydrogen gas waste, poor measurement accuracy and large safety hazards of the existing heat insulation performance detection of a liquid hydrogen container.

[0006] In order to achieve the above-mentioned application purposes, the technical scheme adopted by the present application is as follows: a method for rapidly detecting the heat insulation performance of a liquid hydrogen container, comprising the following steps:

[0007] S1, measuring the specifications of the liquid hydrogen container and the initial state parameters in the liquid hydrogen container;

[0008] S2, calculating initial parameters of the liquid hydrogen and hydrogen gas in the liquid hydrogen container;

[0009] S3, measuring the change rate of the state parameters in the liquid hydrogen container and monitoring the final state parameters in the liquid hydrogen container;

[0010] S4, calculating the final parameters of the liquid hydrogen and hydrogen gas in the liquid hydrogen container according to the final state parameters;

[0011] S5, calculating the evaporation mass flow rate of the liquid hydrogen container according to the change rate of the state parameters in the liquid hydrogen container;

[0012] S6, calculating the thermodynamic energy change rate of the hydrogen gas and liquid hydrogen in the liquid hydrogen container according to the change rate of the state parameters in the liquid hydrogen container, the final state parameters in the liquid hydrogen container and the evaporation mass flow rate of the interface;

[0013] S7, calculating the total internal energy change of the liquid hydrogen container according to the initial state parameters, the final state parameters, the initial parameters and the final parameters of the liquid hydrogen and hydrogen gas, and calculating the total heat transfer amount of the gas phase and liquid phase of the liquid hydrogen container according to the evaporation mass flow rate of the interface and the thermodynamic energy change rate of the hydrogen gas and liquid hydrogen;

[0014] S8, obtaining the adiabatic performance of the liquid hydrogen container according to the comparison between the total heat transfer amount of the gas phase and liquid phase of the liquid hydrogen container and the standard static evaporation rate data.

[0015] Further, in the above-mentioned rapid detection method for the adiabatic performance of the liquid hydrogen container, the specifications of the liquid hydrogen container in S1 include the geometric volume V g , effective volume V e and structural size of the liquid hydrogen container; the initial state parameters include the pressure P1, liquid level height h1, temperature T L1 of the liquid hydrogen and temperature T V1 of the hydrogen gas.

[0016] Further, in the above-mentioned rapid detection method for the adiabatic performance of the liquid hydrogen container, the initial parameters of the liquid hydrogen in S2 include the volume V L1 , density ρ V1 and mass m L1 of the liquid hydrogen; the initial parameters of the hydrogen gas include the volume V g1 , density ρ g1 and mass m g1 of the hydrogen gas.

[0017] Further, in the above-mentioned rapid detection method for the adiabatic performance of the liquid hydrogen container, the change rate of the state parameters in the liquid hydrogen container in S3 includes the change rate dP / dt of the pressure, change rate dT g / dt of the hydrogen gas temperature and change rate dT LThe pressure change rate is obtained by measuring the amount of change in pressure over at least 12 hours and dividing by time; the hydrogen temperature change rate is obtained by measuring the amount of change in hydrogen temperature over at least 12 hours and dividing by time; and the liquid hydrogen temperature change rate is obtained by measuring the amount of change in liquid hydrogen temperature over at least 12 hours and dividing by time.

[0018] Further, in the above method for rapidly detecting the thermal insulation performance of a liquid hydrogen container, the end state parameters in S4 include the liquid hydrogen container pressure P2, the liquid level height h2, and the temperature T L2 and the temperature T V2 of the hydrogen gas at the end; the end parameters of the liquid hydrogen include the liquid hydrogen volume V L2 and the liquid hydrogen mass m L2 ; and the end parameters of the hydrogen gas include the hydrogen gas volume V g2 and the hydrogen gas mass m g2 .

[0019] Further, in the above method for rapidly detecting the thermal insulation performance of a liquid hydrogen container, the liquid hydrogen container gas-liquid interface evaporation mass flow rate in S5 is dm / dt, where where Q Lb , Q Vb are the interface heat transfer amounts of the liquid hydrogen to the hydrogen gas and the hydrogen gas to the liquid hydrogen, respectively, and γ(T s ) is the latent heat of vaporization at the temperature T s .

[0020] Further, in the above method for rapidly detecting the thermal insulation performance of a liquid hydrogen container, the hydrogen gas thermodynamic energy change rate in S6 is the liquid hydrogen thermodynamic energy change rate is where Q V , Q L are the heat transfer amounts of the gas phase and the liquid phase of the liquid hydrogen container, respectively, and h V (T s ), h L (T s ) are the enthalpy values of the hydrogen gas and the liquid hydrogen at the temperature T s , respectively.

[0021] Further, in the above method for rapidly detecting the thermal insulation performance of a liquid hydrogen container, the total internal energy change in S7 is dU, and according to the energy conservation law dU = dU L + dU V , the heat transfer amounts Q V , Q L of the gas phase and the liquid phase of the liquid hydrogen container are calculated based on the internal energy change laws in steps 6 and 7; and the total heat transfer amount Q of the gas phase and the liquid phase of the liquid hydrogen container is Q = Q V + Q L .

[0022] Further, the initial state parameter in the liquid hydrogen container, the final state parameter in the liquid hydrogen container, the initial parameter of the liquid hydrogen and hydrogen gas, and the final parameter of the liquid hydrogen and hydrogen gas are measured by the liquid hydrogen container adiabatic performance rapid detection system; the liquid hydrogen container adiabatic performance rapid detection system comprises a liquid hydrogen container and a liquid level meter, a pressure sensor, a temperature sensor, a safety valve and a measurement and control system arranged in the liquid hydrogen container; the liquid level meter is placed in the liquid hydrogen container and monitors the liquid level of the liquid hydrogen in real time; the pressure sensor monitors the pressure change in the liquid hydrogen container; the temperature sensor monitors the temperature change of the liquid hydrogen and hydrogen gas; and the safety valve prevents overpressure of the liquid hydrogen container.

[0023] The present application has the following advantages:

[0024] (1) The liquid hydrogen container adiabatic performance rapid detection method of the present application does not need to measure the evaporation flow of hydrogen gas, but only measures the pressure and temperature changes of the liquid hydrogen container, thereby avoiding the measurement deviation of the evaporation rate caused by the ambient temperature, the flow meter zero drift, the calibration working condition and the measurement error, and preventing hydrogen gas emission waste and safety hazards.

[0025] (2) The test medium of the liquid hydrogen container of the present application is liquid hydrogen, which does not depend on liquid nitrogen medium, and this method can eliminate the error caused by the difference in medium physical properties, and has higher accuracy and repeatability.

[0026] (3) The detection method of the present application is not only suitable for factory detection of the liquid hydrogen container, but also can be widely applied to daily maintenance and safety inspection of the liquid hydrogen container. Users can judge whether the container has adiabatic performance decay or vacuum failure and the like by periodically or real-time monitoring the pressure rise rate in the liquid hydrogen container, and then take corresponding measures to ensure the safety and reliability of the liquid hydrogen container.

[0027] (4) The liquid hydrogen container adiabatic performance rapid detection method of the present application has the advantages of simplicity, rapidness and low cost, can significantly improve the efficiency and precision of the adiabatic performance detection of the liquid hydrogen container, and can also provide a scientific basis for the maintenance and management of the liquid hydrogen container. The technology is expected to become a standard method for detection of the liquid hydrogen container, and provides strong support for safe use and popularization of liquid hydrogen. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The flow chart of the embodiment of the present application is shown in the figure;

[0029] Figure 2 The principle diagram of the embodiment of the present application is shown in the figure;

[0030] Figure 3 The actual physical property parameter reference diagram of the liquid hydrogen medium of the embodiment of the present application is shown in the figure;

[0031] Figure 4This is a comparison chart of evaporation rate data for liquid hydrogen containers in a specific embodiment of the present invention;

[0032] Figure 5 This is a diagram showing the actual changes in the state parameters inside the liquid hydrogen container in a specific embodiment of the present invention;

[0033] Figure 6 This is a diagram showing the actual changes in the state parameters inside the liquid hydrogen container in a specific embodiment 2 of the present invention. Detailed Implementation

[0034] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0035] Example 1

[0036] like Figure 1 As shown in the figure, this embodiment provides a rapid testing method for the thermal insulation performance of a liquid hydrogen container. First, the specifications of the liquid hydrogen cylinder are identified, mainly recording the container's geometric volume, effective volume, and structural dimensions, providing basic parameters for rapid testing of the liquid hydrogen container's thermal insulation performance. Second, the initial state parameters within the liquid hydrogen container are identified, calculating parameters such as the initial liquid hydrogen volume, hydrogen volume, liquid hydrogen density, hydrogen density, liquid hydrogen mass, and hydrogen mass. Then, the rate of pressure increase and temperature change within the liquid hydrogen container are measured over a period of time. Simultaneously, state parameters such as the liquid hydrogen container pressure, liquid level, and temperatures of liquid hydrogen and hydrogen gas are recorded at the end of the pressure increase. Based on the principle of mass conservation, parameters such as the final liquid hydrogen volume, hydrogen volume, liquid hydrogen mass, and hydrogen mass within the liquid hydrogen container are calculated.

[0037] The principle of the rapid testing method for the thermal insulation performance of liquid hydrogen containers of the present invention can be found in the following reference. Figure 2 A liquid hydrogen container is equipped with a level gauge, a pressure sensor, and a temperature sensor. The level gauge is placed inside the liquid hydrogen container to monitor the liquid hydrogen level in real time. The pressure sensor monitors pressure changes within the liquid hydrogen container, and the temperature sensor monitors temperature changes in both the liquid hydrogen and hydrogen gas. Based on the monitored pressure rise rate and temperature change rate, and with reference to… Figure 3 The variation of actual physical properties of hydrogen, including temperature, density, specific heat, and latent heat of vaporization, with pressure was investigated, and the mass transfer rate dm / dt at the gas-liquid interface in the liquid hydrogen container was calculated. Based on the principle of energy conservation, the rate of change of thermodynamic energy of hydrogen gas and liquid hydrogen within the container was calculated. dU=dU L +dU V Q VQ L The heat transfer rates for the gas and liquid phases of the liquid hydrogen container are respectively, h. V (T s ), h L (T s T are respectively s The enthalpy values ​​of hydrogen gas and liquid hydrogen at the given temperature. Solving the above equations simultaneously, the total heat leakage Q = Q in the gas and liquid phases of the liquid hydrogen container can be calculated. V +Q L You can refer to the following: Figure 4 By comparing the evaporation rate data of the liquid hydrogen container, the thermal insulation performance of the liquid hydrogen container can be directly obtained.

[0038] refer to Figure 5 In this embodiment, the geometric volume of the liquid hydrogen container is 1m³. 3 The initial liquid level was 546 mm, the pressure was 0.2 MPa, and the gas and liquid phase temperatures were 24.2 K and 23 K, respectively. All discharge valves of the liquid hydrogen container were closed, and the pressure, temperature, and liquid level changes were measured for 20 hours. At the end of the measurement, the liquid level was 601 mm, the pressure was 0.6 MPa, and the gas and liquid phase temperatures were 28.3 K and 29.1 K, respectively.

[0039] Due to the increase in liquid hydrogen saturation pressure and temperature, the density of liquid hydrogen decreased, causing the liquid level to rise by 55 mm. According to the formula... The calculated heat transfer rates for the liquid hydrogen gas phase and liquid phase are 3.2 W and 8.1 W respectively, which can be used as a reference. Figure 4 The evaporation rate data comparison shows that the evaporation rate of this liquid hydrogen container is 4.3% / day.

[0040] Example 2

[0041] refer to Figure 6 The geometric volume of the liquid hydrogen container is 1m³. 3 The initial liquid level was 232 mm, the pressure was 0.1 MPa, and the gas and liquid phase temperatures were 20.5 K and 22.2 K, respectively. All drain valves in the liquid hydrogen container were closed, and the pressure, temperature, and liquid level changes were measured for 32 hours. At the end, the liquid level was 193 mm, the pressure was 0.6 MPa, and the gas and liquid phase temperatures were 31.9 K and 28.6 K, respectively. Due to the initially small amount of liquid hydrogen and the large gas phase space, liquid hydrogen evaporation caused the liquid level to drop by 39 mm. According to the formula... The calculated heat transfer rates for the liquid hydrogen gas phase and liquid phase are 1.5 W and 1.9 W respectively, which can be used as a reference. Figure 4 The evaporation rate data comparison shows that the evaporation rate of this liquid hydrogen container is 4.2% / d.

[0042] The two embodiments above are for two different initial states of the same liquid hydrogen cylinder, and the evaporation rate error of the liquid hydrogen container is 2.3% according to the liquid hydrogen container adiabatic performance rapid detection method provided by the application, and the results show that the detection method provided by the application has high accuracy and is not limited by the initial state of the liquid hydrogen container. The technology is expected to become a standard method for detecting liquid hydrogen containers, providing strong support for the safe use and promotion of liquid hydrogen.

[0043] The above specific embodiments further illustrate the purpose, technical solutions and advantages of the application. It should be understood that the above description is only a specific embodiment of the application and is not intended to limit the protection scope of the application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application should be included in the protection scope of the application.

[0044] It should be noted that in this document, terms such as "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method.

Claims

1. A method for rapidly detecting the thermal insulation performance of a liquid hydrogen container, characterized by, The method comprises the following steps: S1, measuring the liquid hydrogen container specification and initial state parameters in the liquid hydrogen container; the liquid hydrogen container specification includes the liquid hydrogen container geometric volume V g , effective volume V e , and structure size; the initial state parameters include the liquid hydrogen container pressure P1, liquid level height h1, liquid hydrogen temperature T L1 , and hydrogen gas temperature T V1 ; S2, calculating initial parameters of liquid hydrogen and hydrogen gas in the liquid hydrogen container; the initial parameters of the liquid hydrogen include a liquid hydrogen volume V L1 , a liquid hydrogen density p V1 , and a liquid hydrogen mass m L1 ; the initial parameters of the hydrogen gas include a hydrogen gas volume V g1 , a hydrogen gas density p g1 , and a hydrogen gas mass m g1 ; S3, measuring the rate of change of the state parameters in the liquid hydrogen container and monitoring the final state parameters in the liquid hydrogen container; the rate of change of the state parameters in the liquid hydrogen container includes a rate of change of pressure dP / dt, a rate of change of hydrogen temperature dT g / dt, and a rate of change of liquid hydrogen temperature dT L / dt; the rate of change of pressure is obtained by measuring the amount of change of pressure over at least 12 hours divided by the time; the rate of change of hydrogen temperature is obtained by measuring the amount of change of hydrogen temperature over at least 12 hours divided by the time; and the rate of change of liquid hydrogen temperature is obtained by measuring the amount of change of liquid hydrogen temperature over at least 12 hours divided by the time; S4, calculating the end parameters of the liquid hydrogen and hydrogen gas in the liquid hydrogen container according to the end state parameters; the end state parameters include the pressure P2, the liquid level height h2, the temperature T of the liquid hydrogen and the temperature T of the hydrogen gas at the end; the end parameters of the liquid hydrogen include the volume V and the mass m of the liquid hydrogen; the end parameters of the hydrogen gas include the volume V and the mass m of the hydrogen gas L2 . V2 . L2 . L2 . g2 . g2 . the liquid hydrogen and the hydrogen gas at the end; the end parameters of the liquid hydrogen include the volume V and the mass m of the liquid hydrogen; the end parameters of the hydrogen gas include the volume V and the mass m of the hydrogen gas S5, calculating the evaporation mass flow rate of the gas-liquid interface of the liquid hydrogen container according to the rate of change of the state parameter in the liquid hydrogen container; the evaporation mass flow rate of the gas-liquid interface of the liquid hydrogen container is dm / dt, wherein wherein Q Lb , Q Vb respectively the interfacial heat transfer of liquid hydrogen to hydrogen gas and hydrogen gas to liquid hydrogen, γ(T s ) the latent heat of vaporization at T s temperature; S6, calculating the thermodynamic energy change rate of hydrogen gas and liquid hydrogen in the liquid hydrogen container according to the change rate of the state parameter in the liquid hydrogen container, the final state parameter in the liquid hydrogen container and the interface evaporation mass flow rate; the thermodynamic energy change rate of hydrogen gas the thermodynamic energy change rate of liquid hydrogen wherein Q V , Q L are the heat transfer amounts of the gas phase and the liquid phase of the liquid hydrogen container respectively, h V (T s ), h L (T s ) are the enthalpy values of hydrogen gas and liquid hydrogen at T s temperature respectively; S7, calculating the total internal energy change of the liquid hydrogen container according to the initial state parameters, the final state parameters, the initial parameters and the final parameters of the liquid hydrogen and hydrogen gas, and calculating the total heat transfer of the gas phase and the liquid phase of the liquid hydrogen container according to the interface evaporation mass flow rate and the thermodynamic energy change rate of the hydrogen gas and the liquid hydrogen; S8, obtaining the adiabatic performance of the liquid hydrogen container according to the comparison between the total heat transfer of the gas phase and the liquid phase of the liquid hydrogen container and the standard static evaporation rate data.

2. The method of claim 1, wherein the method is characterized by: The total internal energy change in S7 is dU, according to the energy conservation dU = dU L + dU V , combined with the change rule of internal energy in steps 6 and 7, the heat transfer amount Q V , Q L of the gas phase and the liquid phase of the liquid hydrogen container is calculated V + Q L .

3. The method for rapidly detecting the thermal insulation performance of a liquid hydrogen container according to any one of claims 1 to 2, characterized in that, The initial state parameters in the liquid hydrogen container, the final state parameters in the liquid hydrogen container, the initial parameters of the liquid hydrogen and hydrogen gas, and the final parameters of the liquid hydrogen and hydrogen gas are measured by the liquid hydrogen container adiabatic performance rapid detection system; the liquid hydrogen container adiabatic performance rapid detection system comprises a liquid hydrogen container and a liquid level meter, a pressure sensor, a temperature sensor, a safety valve and a measurement and control system arranged in the liquid hydrogen container; the liquid level meter is placed in the liquid hydrogen container and monitors the liquid level of the liquid hydrogen in real time; the pressure sensor monitors the pressure change in the liquid hydrogen container; the temperature sensor monitors the temperature change of the liquid hydrogen and hydrogen gas; and the safety valve prevents overpressure of the liquid hydrogen container.

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