Transient intelligent measuring instrument for two-phase thermophysical property of LNG (Liquefied Natural Gas)

Abstract

The invention relates to the technical field of LNG operation, and discloses an LNG two-phase thermophysical property transient intelligent measuring instrument which is characterized in that an inlet connecting short section is arranged on one side of a double-oscillation-tube Coriolis densimeter, a temperature sensor and a pressure sensor are installed on the LNG from the inlet connecting short section, and an outlet connecting short section is arranged on the other side of the double-oscillation-tube Coriolis densimeter; the integrated transmitter is connected with the double-oscillation-tube Coriolis densimeter and used for receiving and displaying LNG density and LNG flow parameters, temperature parameters and pressure parameters transmitted by the double-oscillation-tube Coriolis densimeter. The single chip microcomputer is connected with the double-oscillation-tube Coriolis densimeter and is connected with the temperature sensor, the pressure sensor and the integrated transmitter through communication cables; or the collected parameters are remotely transmitted through a communication cable; a local calculation module is arranged in the single-chip microcomputer, and the heat productivity, the specific heat capacity, the heat conductivity coefficient and the enthalpy value are obtained through real-time calculation according to the received parameters; all the components are connected with a power line.

Description

Technical Field

[0001] The invention relates to the technical field of LNG operation, in particular to an intelligent transient measuring instrument for two-phase thermal properties of LNG. Background Art

[0002] In LNG liquefaction plants and LNG storage and transportation facilities, the current direct measurement parameters for the measurement of the thermophysical properties of LNG in liquid and low-temperature gaseous states are limited to density, as well as the three auxiliary state parameters of temperature, pressure, and flow rate. Other important thermophysical parameters include specific heat capacity, thermal conductivity, and enthalpy. Among them, the commonly used thermophysical parameters in production and operation are density and calorific value. The density of LNG is directly measured using an ultra-low temperature density meter; the calorific value of LNG is calculated by the computer of the chromatograph analyzer based on the measured component data after LNG gasification using the combined method of "low temperature sampling device + traditional chromatograph"; the temperature of LNG is measured using an auxiliary thermometer, the pressure of LNG is measured using a pressure gauge, and the flow rate of LNG is measured using a flowmeter; while the three thermophysical parameters of specific heat capacity, thermal conductivity, and enthalpy are not commonly used in production. The existing technology uses the "low temperature sampling device + laboratory" offline measurement method, and uses different professional instruments to measure specific heat capacity, thermal conductivity, and enthalpy.

[0003] For the purpose of simplification, the thermophysical parameters in a strict sense include density, calorific value, specific heat capacity, thermal conductivity, enthalpy value, and the state parameters in a strict sense include temperature, pressure, and flow rate, which are collectively referred to as thermophysical parameters in a broad sense.

[0004] In general, to measure the thermophysical parameters of LNG liquid and cryogenic gas, at least one instrument is required for each parameter, and only density, temperature, pressure, and flow rate can be measured online. Even if the calorific value parameter is measured continuously, it can only be measured periodically at intervals of 4 to 5 minutes, and the specific heat capacity, thermal conductivity, and enthalpy value can only be measured offline in the laboratory. There are two main problems:

[0005] First, in LNG liquefaction plants and LNG storage and transportation facilities, different instruments are needed to measure various thermophysical parameters of LNG liquid and low-temperature gas. In particular, the measurement of calorific value parameters requires a combination of two instruments, which is expensive (average RMB 10 million per set). Only a small number of instruments (1 to 2 sets) can be deployed, and it is impossible to independently deploy them in each pipeline and LNG export unit, resulting in the inability to accurately grasp the specific distribution of thermophysical parameters of each important node in the entire plant.

[0006] Secondly, most thermophysical parameters cannot be measured in real time. For example, calorific value can only be measured by periodic sampling, specific heat capacity, thermal conductivity, and enthalpy can only be measured in the laboratory. Only density and temperature, pressure, and flow rate can be simply measured in real time. As a result, it is impossible to accurately grasp the real-time transient changes in thermophysical parameters of each important node within the entire plant. This problem is more prominent when the current LNG composition changes greatly and the operating conditions change rapidly.

[0007] There are currently no known solutions to the two main problems mentioned above. Summary of the invention

[0008] In view of the above problems, the purpose of the present invention is to provide an intelligent transient measuring instrument for two-phase thermophysical properties of LNG, which can realize real-time transient measurement of thermophysical property parameters of LNG in liquid and low-temperature gaseous states.

[0009] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an intelligent transient measuring instrument for two-phase thermal properties of LNG, which includes: a double-oscillation tube Coriolis densitometer, an inlet connecting nipple, an outlet connecting nipple, a temperature sensor, a pressure sensor, an integrated transmitter, a single-chip microcomputer, a communication cable and a power cord; an inlet connecting nipple is provided on one side of the double-oscillation tube Coriolis densitometer, and LNG enters from the inlet connecting nipple; a temperature sensor and a pressure sensor for measuring ultra-low temperature medium are installed on the inlet connecting nipple of LNG to measure the temperature and pressure parameters of the LNG flowing through in real time; an outlet connecting nipple is provided on the other side of the double-oscillation tube Coriolis densitometer; the integrated transmitter is connected to the double-oscillation tube Coriolis densitometer and communicates with the double-oscillation tube Coriolis densitometer through the inlet connecting nipple. The cable is connected to the temperature sensor and the pressure sensor, and the integrated transmitter is used to receive and display the LNG density and LNG flow parameters, temperature and pressure parameters transmitted by the dual-oscillation tube Coriolis density meter; the single-chip microcomputer is connected to the dual-oscillation tube Coriolis density meter, and is connected to the temperature sensor, pressure sensor and integrated transmitter through the communication cable; or, the collected LNG density and LNG flow parameters, temperature and pressure parameters are further transmitted remotely through the communication cable; an on-site calculation module is provided in the single-chip microcomputer, which performs real-time calculation according to the received parameters to obtain the calorific value, specific heat capacity, thermal conductivity and enthalpy value; the dual-oscillation tube Coriolis density meter, temperature sensor, pressure sensor, integrated transmitter and single-chip microcomputer are all connected to the power cord.

[0010] Furthermore, the single chip microcomputer includes a local calculation module, a real-time data acquisition module, a database, a local digital display module and an output module;

[0011] The real-time data acquisition module is used to collect temperature, pressure, density and flow in real time, transmit them to the local calculation module, and store them in the database;

[0012] The calorific value, specific heat capacity, thermal conductivity, enthalpy parameters calculated in real time by the local calculation module are transmitted to the local digital display module and output module together with the real-time measured temperature, pressure, density, and flow parameters, and further transmitted remotely through communication cables.

[0013] Furthermore, the local calculation module of the single chip microcomputer includes: a calorific value calculation module, a specific heat capacity calculation module, a thermal conductivity calculation module and an enthalpy value calculation module;

[0014] The calorific value calculation module calculates the calorific value based on the temperature, pressure, density and flow parameters transmitted by the real-time data acquisition module and the data in the database through the calorific value algorithm Q=F(P, T, ρ0); wherein Q is the calorific value, P is the measured pressure, T is the measured temperature, and ρ0 is the density under the conditions of absolute pressure of 101.325 kpa and -160°C;

[0015] The specific heat capacity calculation module calculates the specific heat capacity according to the temperature, pressure, density and flow parameters transmitted by the real-time data acquisition module and calls the data in the database, and calculates the specific heat capacity through the specific heat capacity algorithm c=F(P, T, ρ0); c is the specific heat capacity;

[0016] The thermal conductivity calculation module calculates the thermal conductivity according to the temperature, pressure, density and flow parameters transmitted by the real-time data acquisition module and calls the data in the database, and calculates the thermal conductivity through the thermal conductivity algorithm k=F(P, T, ρ0); k is the thermal conductivity;

[0017] The enthalpy calculation module calculates the enthalpy value based on the temperature, pressure, density and flow parameters transmitted by the real-time data acquisition module and calls the data in the database, and calculates the enthalpy value through the enthalpy value algorithm H=F(P, T, ρ0); H is the enthalpy value.

[0018] Furthermore, the calorific value algorithm Q = F (P, T, ρ0) is:

[0019]

[0020] Among them, a1~a4 are calorific value coefficients, which are obtained by high-precision data fitting through multiple groups of LNG physical property parameter tables in the database.

[0021] Furthermore, the specific heat capacity algorithm c=F(P, T, ρ0) is:

[0022]

[0023] Among them, b1~b4 are specific heat capacity coefficients, which are obtained by high-precision data fitting through multiple groups of LNG physical property parameter tables in the database.

[0024] Furthermore, the thermal conductivity algorithm k=F(P, T, ρ0) is:

[0025]

[0026] Among them, c1~c4 are thermal conductivity coefficients, which are obtained by high-precision data fitting through multiple groups of LNG physical property parameter tables in the database.

[0027] Furthermore, the enthalpy algorithm H=F(P, T, ρ0) is:

[0028]

[0029] Among them, d1~d4 are enthalpy coefficients, which are obtained by high-precision data fitting through multiple groups of LNG physical property parameter tables in the database.

[0030] Furthermore, the calculation results are entered into the database again for verification before output, and the results are output after passing the verification.

[0031] Furthermore, based on the density value, the database is queried to find the density value closest to the real-time measured density parameter under the same temperature and pressure parameters as the real-time measured value, and then the parameter table of this group of LNG is located, and the calorific value, specific heat capacity, thermal conductivity, and enthalpy value parameters of this group of LNG under absolute pressure of 101.325kpa and -160℃ are queried in the database for comparison and verification.

[0032] Further, the comparison and verification is:

[0033] If the calculation result of each parameter deviates from the query parameter by less than or equal to 1%, the calculation result is used as the output result;

[0034] If the calculation result of each parameter deviates from the query parameter by more than 1%, the arithmetic mean of the calculation result and the query parameter is used as the output result.

[0035] The present invention adopts the above technical solution, which has the following advantages:

[0036] 1. The present invention solves the problem of real-time transient measurement of the thermophysical parameters of LNG liquid and cryogenic gas, and realizes the online real-time parallel transient precise measurement of multiple thermophysical parameters through a set of cost-effective integrated instruments.

[0037] 2. The intelligent instrument used in the present invention has product value and can be widely deployed and installed in LNG liquefaction plants and LNG storage and transportation facilities. It can accurately grasp the specific distribution of thermal physical parameters of each important node in the whole plant, as well as the real-time transient changes of thermal physical parameters at each important node.

[0038] 3. Under the current circumstances where the LNG components vary greatly and the operating conditions change rapidly, the present invention can realize the identification of abnormal production quality fluctuations in the multi-channel LNG production, distribution and distribution processes, the accurate verification of the energy balance of the entire plant, and the calculation of economic benefits based on the dynamic total energy metering and sales. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the overall structure of the LNG two-phase thermal property transient intelligent measuring instrument in an embodiment of the present invention;

[0040] Figure 2 Schematic diagram of an on-site calculation module of a single chip microcomputer in an embodiment of the present invention;

[0041] Reference numerals:

[0042] 1-Dual oscillation tube Coriolis densitometer; 2-Inlet connection short section; 3-Outlet connection short section; 4-Temperature sensor; 5-Pressure sensor; 6-Integrated transmitter; 7-Single chip microcomputer; 8-Communication cable; 9-Power cord. DETAILED DESCRIPTION

[0043] In order to solve the problem in the prior art that it is impossible to accurately grasp the specific distribution of thermophysical parameters of each important node in the whole plant and the real-time transient changes, the present invention proposes an LNG two-phase thermophysical transient intelligent measuring instrument, wherein the thermophysical parameters include density, calorific value, specific heat capacity, thermal conductivity, enthalpy value, as well as temperature, pressure, and flow rate, so as to realize online real-time parallel transient measurement of multiple thermophysical parameters.

[0044] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0045] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0046] In one embodiment of the present invention, an intelligent transient measurement instrument for two-phase thermal properties of LNG is provided, which involves online real-time transient measurement of thermal properties of LNG and boil-off gas in LNG liquefaction plants and LNG storage and transportation facilities. Figure 1 As shown, the instrument includes: a double oscillation tube Coriolis densitometer 1, an inlet connecting short section 2, an outlet connecting short section 3, a temperature sensor 4, a pressure sensor 5, an integrated transmitter 6, a single chip computer 7, a communication cable 8 and a power cord 9.

[0047] An inlet connection nipple 2 is provided on one side of the double oscillation tube Coriolis densitometer 1, and LNG enters from the inlet connection nipple 2; a temperature sensor 4 and a pressure sensor 5 for measuring ultra-low temperature media are installed on the LNG inlet connection nipple 2, and the temperature sensor 4 and the pressure sensor 5 measure the temperature and pressure parameters of the LNG flowing through in real time.

[0048] An outlet connecting nipple 3 is provided on the other side of the double oscillation tube Coriolis densitometer 1 . After the LNG enters the double oscillation tube Coriolis densitometer 1 through the inlet connecting nipple 2 , it flows out through the outlet connecting nipple 3 .

[0049] The integrated transmitter 6 is connected to the dual oscillation tube Coriolis densitometer 1, and is connected to the temperature sensor 4 and the pressure sensor 5 via a communication cable 8. The integrated transmitter 6 is used to receive and display the LNG density and LNG flow parameters, temperature and pressure parameters transmitted by the dual oscillation tube Coriolis densitometer 1.

[0050] The single chip computer 7 is connected to the dual oscillation tube Coriolis densitometer 1, and is connected to the temperature sensor 4, the pressure sensor 5 and the integrated transmitter 6 via the communication cable 8; or, the collected LNG density and LNG flow parameters, temperature and pressure parameters are further transmitted remotely via the communication cable 8 to an external device.

[0051] The single chip computer 7 is provided with an on-site calculation module, which performs real-time calculation according to the received parameters, and obtains four parameters, namely, calorific value, specific heat capacity, thermal conductivity and enthalpy value, by real-time calculation.

[0052] The double oscillation tube Coriolis densitometer 1, the temperature sensor 4, the pressure sensor 5, the integrated transmitter 6 and the single chip computer 7 are all connected to the power line 9 to ensure power supply and execution of actions.

[0053] In the above embodiment, during the period when LNG enters the double oscillation tube Coriolis densitometer 1, the density parameters of LNG are directly measured by the LNG entering the double oscillation tube Coriolis densitometer 1; due to the measurement characteristics of the double oscillation tube Coriolis densitometer 1 itself, that is, the volume of LNG entering the double oscillation tube is a fixed indicator, the LNG flow parameters flowing through the double oscillation tube Coriolis densitometer 1 can be automatically obtained based on the basic formula that mass is equal to the product of density and volume.

[0054] In the above embodiment, the single chip microcomputer 7 includes, in addition to the local calculation module, a real-time data acquisition module, a database, a local digital display module and an output module.

[0055] The real-time data acquisition module is used to collect temperature, pressure, density and flow in real time. Specifically, after the four parameters of temperature, pressure, density and flow are transmitted to the single-chip microcomputer 7 in real time, the four real-time parameters of temperature, pressure, density and flow are collected by the embedded real-time data acquisition module, and transmitted to the local calculation module and stored in the database at the same time;

[0056] The four parameters of calorific value, specific heat capacity, thermal conductivity and enthalpy value calculated in real time by the local calculation module are transmitted to the local digital display module and output module together with the four parameters of temperature, pressure, density and flow measured in real time, and can be further transmitted remotely through the communication cable 8.

[0057] In this embodiment, the single-chip microcomputer 7 is a conventional industrial microcomputer, which, through programming configuration, has embedded four modules, namely, a real-time data acquisition module, an on-site calculation module, an on-site digital display module and an output module. The on-site digital display module displays on-site through its own display screen, and outputs data from the output module through its own multi-type communication interface and transmits it through the communication cable 8.

[0058] In this embodiment, the local digital display module is used to simultaneously display various parameters of the local calculation module for on-site modification and adjustment of settings.

[0059] In this embodiment, the database is a physical property database composed of eight parameters, including components, pressure, temperature, density, calorific value, specific heat capacity, thermal conductivity, and enthalpy value, of multiple groups of LNG and boil-off gas, which are jointly constructed by data generated by commercial software and measured data. Each group of LNG and each group of boil-off gas independently includes a set of physical property parameter tables, including components, pressure, temperature, density, calorific value, specific heat capacity, thermal conductivity, and enthalpy value, totaling eight parameters. The eight parameters of multiple groups of LNG and multiple groups of boil-off gas constitute the database.

[0060] In the above embodiments, it is also applicable to replace LNG with boil-off gas of LNG.

[0061] In a preferred embodiment, Figure 2 As shown, the local calculation module of the single chip computer 7 includes: a calorific value calculation module, a specific heat capacity calculation module, a thermal conductivity calculation module and an enthalpy value calculation module.

[0062] The calorific value calculation module calculates the calorific value through the calorific value algorithm Q=F(P, T, ρ0) according to the temperature, pressure, density and flow parameters transmitted by the real-time data acquisition module and calls the data in the database;

[0063] The specific heat capacity calculation module calculates the specific heat capacity through the specific heat capacity algorithm c=F(P, T, ρ0) according to the temperature, pressure, density and flow parameters transmitted by the real-time data acquisition module and calling the data in the database;

[0064] The thermal conductivity calculation module calculates the thermal conductivity through the thermal conductivity algorithm k=F(P, T, ρ0) according to the temperature, pressure, density and flow parameters transmitted by the real-time data acquisition module and calling the data in the database;

[0065] The enthalpy calculation module calculates the enthalpy value based on the temperature, pressure, density and flow parameters transmitted by the real-time data acquisition module and calls the data in the database, and calculates the enthalpy value through the enthalpy algorithm H=F(P, T, ρ0).

[0066] In the above embodiment, the calorific value algorithm Q=F(P, T, ρ0) is:

[0067]

[0068] Wherein, Q is the calorific value, P is the measured pressure, T is the measured temperature, and ρ0 is the density under the condition of absolute pressure of 101.325 kPa and -160°C. a1~a4 are calorific value coefficients, which are obtained by high-precision data fitting of multiple groups of LNG physical property parameter tables in the database, and the number of multiple groups of LNG is not less than 2000.

[0069] In this embodiment, a1 = 4.177861E+02; a2 = -8.625425E-01; a3 = 3.3711066E-03; a4 = 6.7277081E-05. Where E is an exponent, for example, E-03 means e -3 .

[0070] In this embodiment, ρ0 needs to query the database to find a group of LNG that is closest to the measured density under the measured pressure P and measured temperature T, such as 300Kpa and -158°C, and then query the physical property parameter table of this group of LNG to obtain the density value under the absolute pressure of 101.325kpa and -160°C, such as 0.7758kg / m 3 .

[0071] According to the calculation results of formula 1, the calculated result of Q is 43.96MJ / Sm 3 Before outputting the result, you need to enter the database again to query the physical property parameter table of this set of LNG for verification.

[0072] In the above embodiment, the specific heat capacity algorithm c=F(P, T, ρ0) is:

[0073]

[0074] Among them, c is the specific heat capacity, because the specific heat capacity depends on the specific temperature T and pressure P, so the specific heat capacity is the specific heat capacity under the conditions of absolute pressure 101.325kpa and -160℃. b1~b4 are specific heat capacity coefficients, which are obtained by high-precision data fitting of multiple groups of LNG physical property parameter tables in the database, and the number of multiple groups of LNG is not less than 2000.

[0075] In this embodiment, b1=3.440543E+01; b2=8.447683E-01; b3=6.2287333E-03; b4=2.333500E-05.

[0076] In this embodiment, the specific heat capacity is calculated in the same way as the calorific value Q, and a high-precision mathematical correlation formula with the density at an absolute pressure of 101.325 kpa and -160°C is established. When the calorific value Q is first calculated, a group of LNG with highly similar physical properties is nearly locked in, and the density value at an absolute pressure of 101.325 kpa and -160°C is also obtained.

[0077] According to the calculation result of formula 2, the calculated result of c is 3.53 kJ / (kg·K). Before it is used as the output result, it is necessary to enter the database again to query the physical property parameter table of this group of LNG for verification.

[0078] In the above embodiment, the thermal conductivity algorithm k=F(P, T, ρ0) is:

[0079]

[0080] Among them, k is the thermal conductivity, because the thermal conductivity depends on the specific temperature T and pressure P, so the thermal conductivity is the thermal conductivity under the condition of absolute pressure 101.325kpa and -160℃. c1~c4 are thermal conductivity coefficients, which are obtained by high-precision data fitting of multiple groups of LNG physical parameter tables in the database, and the number of multiple groups of LNG is not less than 2000.

[0081] In this embodiment, c1=0.157332E+01; c2=1.447765E-01; c3=3.560177E-03; c4=5.564467E-05.

[0082] In this embodiment, the thermal conductivity is calculated in the same way as the calorific value Q, and a high-precision mathematical correlation formula is established with the density at an absolute pressure of 101.325 kpa and -160°C. When the calorific value Q is first calculated, a group of LNG with highly similar physical properties is nearly locked in, and the density value at an absolute pressure of 101.325 kpa and -160°C is also obtained.

[0083] According to the calculation result of formula 3, the calculated result of k is 0.16W / (m·K). Before it is used as the output result, it is necessary to enter the database again to query the physical property parameter table of this group of LNG for verification.

[0084] In the above embodiment, the enthalpy value algorithm H=F(P, T, ρ0) is:

[0085]

[0086] Among them, H is the enthalpy value. Since the enthalpy value depends on the specific temperature T and pressure P, the enthalpy value is the enthalpy value under the conditions of absolute pressure 101.325kpa and -160°C. d1~d4 are enthalpy coefficients, which are obtained by high-precision data fitting of multiple groups of LNG physical property parameter tables in the database, and the number of multiple groups of LNG is not less than 2000.

[0087] In this embodiment, d1=5.587891E+03; d2=8.627709E-01; d3=3.443265E-03; d4=1.2320188E-05.

[0088] In this embodiment, the enthalpy value is calculated in the same way as the calorific value Q, and a high-precision mathematical correlation formula is established with the density under conditions of absolute pressure 101.325 kpa and -160°C. When the calorific value Q is first calculated, a group of LNG with highly similar physical properties is nearly locked in, and the density value under conditions of absolute pressure 101.325 kpa and -160°C is also obtained.

[0089] According to the calculation result of formula 4, the calculated result of H is 5583.50 kJ / kg. Before it is used as the output result, it is necessary to enter the database again to query the physical property parameter table of this group of LNG for verification.

[0090] In the above embodiments, the calculation results are entered into the database again for verification before being output, and the results are output after the verification passes.

[0091] Among them, the verification method is to use the density value as the benchmark, query the database, and query the density value closest to the real-time measured density parameter under the same temperature and pressure parameters as the real-time measured value, and then locate the parameter table of this group of LNG, query the database for the calorific value, specific heat capacity, thermal conductivity, and enthalpy value of this group of LNG under absolute pressure of 101.325kpa and -160℃ for comparison and verification.

[0092] If the calculation result of each parameter deviates from the query parameter by less than or equal to 1% (calculated with the query parameter as the dividend), the calculation result is used as the output result;

[0093] If the calculation result of each parameter deviates from the query parameter by more than 1%, the arithmetic mean of the calculation result and the query parameter is used as the output result.

[0094] For example, taking specific heat capacity as an example, the calculated result of c is 3.53 kJ / (kg·K), and the specific heat capacity data of this group of LNG in the query database is 3.47 kJ / (kg·K), then the deviation is 1.73%. The arithmetic mean of the calculated result of c 3.53 kJ / (kg·K) and the query data 3.47 kJ / (kg·K) is 3.50 kJ / (kg·K) as the output result.

[0095] In the above embodiments, the same is also applicable where LNG is replaced with boil-off gas of LNG.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An intelligent transient measuring instrument for two-phase thermal properties of LNG, characterized in that: include: A double oscillation tube Coriolis densitometer (1), an inlet connection nipple (2), an outlet connection nipple (3), a temperature sensor (4), a pressure sensor (5), an integrated transmitter (6), a single chip computer (7), a communication cable (8) and a power cord (9); An inlet connection nipple (2) is provided on one side of the double oscillation tube Coriolis densitometer (1), and LNG enters from the inlet connection nipple (2); a temperature sensor (4) and a pressure sensor (5) for measuring ultra-low temperature medium are installed on the LNG inlet connection nipple (2) to measure the temperature and pressure parameters of the LNG flowing through in real time; An outlet connection nipple (3) is provided on the other side of the double oscillation tube Coriolis densitometer (1); The integrated transmitter (6) is connected to the double oscillation tube Coriolis density meter (1), and is connected to the temperature sensor (4) and the pressure sensor (5) via a communication cable (8). The integrated transmitter (6) is used to receive the LNG density and LNG flow parameters, temperature and pressure parameters transmitted by the double oscillation tube Coriolis density meter (1), and display them; The single chip computer (7) is connected to the double oscillation tube Coriolis densitometer (1), and is connected to the temperature sensor (4), the pressure sensor (5) and the integrated transmitter (6) via a communication cable (8); or the collected LNG density and LNG flow parameters, temperature and pressure parameters are further remotely transmitted via the communication cable (8); The single chip computer (7) is provided with an on-site calculation module, which performs real-time calculation according to the received parameters to obtain the calorific value, specific heat capacity, thermal conductivity and enthalpy value; The double-oscillation tube Coriolis densitometer (1), the temperature sensor (4), the pressure sensor (5), the integrated transmitter (6) and the single-chip computer (7) are all connected to the power line (9).

2. The LNG two-phase thermal property transient intelligent measuring instrument as claimed in claim 1 is characterized in that: The single chip computer (7) includes an on-site calculation module, a real-time data acquisition module, a database, an on-site digital display module and an output module; The real-time data acquisition module is used to collect temperature, pressure, density and flow in real time, transmit them to the local calculation module, and store them in the database; The calorific value, specific heat capacity, thermal conductivity, and enthalpy parameters calculated in real time by the local calculation module are transmitted together with the real-time measured temperature, pressure, density, and flow parameters to the local digital display module and output module, and further transmitted remotely via a communication cable (8).

3. The LNG two-phase thermal property transient intelligent measuring instrument as claimed in claim 2 is characterized in that: The on-site calculation module of the single chip computer (7) comprises: a calorific value calculation module, a specific heat capacity calculation module, a thermal conductivity calculation module and an enthalpy value calculation module; The calorific value calculation module calculates the calorific value based on the temperature, pressure, density and flow parameters transmitted by the real-time data acquisition module and the data in the database through the calorific value algorithm Q=F(P, T, ρ0); wherein Q is the calorific value, P is the measured pressure, T is the measured temperature, and ρ0 is the density under the conditions of absolute pressure of 101.325 kpa and -160°C; The specific heat capacity calculation module calculates the specific heat capacity according to the temperature, pressure, density and flow parameters transmitted by the real-time data acquisition module and calls the data in the database, and calculates the specific heat capacity through the specific heat capacity algorithm c=F(P, T, ρ0); c is the specific heat capacity; The thermal conductivity calculation module calculates the thermal conductivity according to the temperature, pressure, density and flow parameters transmitted by the real-time data acquisition module and calls the data in the database, and calculates the thermal conductivity through the thermal conductivity algorithm k=F(P, T, ρ0); k is the thermal conductivity; The enthalpy calculation module calculates the enthalpy value based on the temperature, pressure, density and flow parameters transmitted by the real-time data acquisition module and calls the data in the database, and calculates the enthalpy value through the enthalpy value algorithm H=F(P, T, ρ0); H is the enthalpy value.

4. The LNG two-phase thermal property transient intelligent measuring instrument as claimed in claim 3 is characterized in that: The calorific value algorithm Q = F (P, T, ρ0) is: Among them, a1~a4 are calorific value coefficients, which are obtained by high-precision data fitting through multiple groups of LNG physical property parameter tables in the database.

5. The LNG two-phase thermal property transient intelligent measuring instrument as claimed in claim 3, characterized in that: The specific heat capacity algorithm c=F(P, T, ρ0) is: Among them, b1~b4 are specific heat capacity coefficients, which are obtained by high-precision data fitting through multiple groups of LNG physical property parameter tables in the database.

6. The LNG two-phase thermal property transient intelligent measuring instrument as claimed in claim 3, characterized in that: The thermal conductivity algorithm k = F (P, T, ρ0) is: Among them, c1~c4 are thermal conductivity coefficients, which are obtained by high-precision data fitting through multiple groups of LNG physical property parameter tables in the database.

7. The LNG two-phase thermal property transient intelligent measuring instrument as claimed in claim 3, characterized in that: The enthalpy value algorithm H=F(P, T, ρ0) is: Among them, d1~d4 are enthalpy coefficients, which are obtained by high-precision data fitting through multiple groups of LNG physical property parameter tables in the database.

8. The LNG two-phase thermal property transient intelligent measuring instrument according to any one of claims 4 to 7, characterized in that: The calculation results are entered into the database again for verification before output, and the results are output after the verification is passed.

9. The LNG two-phase thermal property transient intelligent measuring instrument as described in claim 8, characterized in that: The verification method is: take the density value as the benchmark, query the database, and find the density value closest to the real-time measured density parameter under the same temperature and pressure parameters as the real-time measured value, and then locate the parameter table of this group of LNG, query the database for the calorific value, specific heat capacity, thermal conductivity, and enthalpy value parameters of this group of LNG under absolute pressure of 101.325kpa and -160℃, and perform comparison and verification.

10. The LNG two-phase thermal property transient intelligent measuring instrument as described in claim 9, characterized in that: The comparison and verification are: If the calculation result of each parameter deviates from the query parameter by less than or equal to 1%, the calculation result is used as the output result; If the calculation result of each parameter deviates from the query parameter by more than 1%, the arithmetic mean of the calculation result and the query parameter is used as the output result.

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