Device for measuring gas solubility and application thereof

Abstract

The invention relates to a device for measuring gas solubility, which comprises a phase equilibrium system, an analysis system and a data processing system, the phase equilibrium system is connected with the analysis system, and the phase equilibrium system and the analysis system are respectively connected with the data processing system. The balance system comprises a gas phase collection container module, a temperature control module, a gas-liquid mixing container module, a first pressure sensor, a first temperature sensor, a second pressure sensor and a second temperature sensor, wherein the gas phase collection container module and the gas-liquid mixing container module are connected with each other through a communicating pipe. The analysis system comprises a gas chromatograph and a six-way valve, and the gas-liquid mixing container module and the gas chromatograph are connected through the six-way valve. The invention also relates to a method for measuring the gas solubility by using the device.

Description

Technical Field

[0001] The present invention relates to the technical field of dissolution parameter testing, and particularly to an apparatus for measuring the solubility of gases and its applications. Background Art

[0002] This section provides background information related to the present application, which does not necessarily constitute prior art.

[0003] Almost all industrial processes involving gas-liquid contact involve the dissolution of gases in liquids. The measurement of gas solubility mainly refers to the process of measuring the dissolution data of gases in liquids at a certain temperature and pressure. Methods for measuring gas solubility include static measurement methods, quartz crystal microbalance methods, weighing methods, gas chromatography methods, bubble point methods, equal volume saturation methods, etc. In the chemical, pharmaceutical, and food industries, since gas solubility affects the reaction rate and the separation and purification process, accurately measuring gas solubility is crucial for controlling and optimizing the production process.

[0004] Currently, most apparatuses for measuring the solubility of gases in liquids use static measurement methods or weighing methods for determination. The static measurement method mainly calculates the solubility of gases in solvents based on the PVT changes of gases during the dissolution process (PVT changes refer to the change process of pressure, volume, and temperature). It is applicable to the measurement of gas solubility in non-volatile or extremely difficult to volatilize solvent systems. The weighing method determines the solubility of gases by the change in weight before and after gas dissolution. Currently, apparatuses for measuring the solubility of gases in liquids have the following technical problems:

[0005] 1. For volatile solvent systems, at higher temperatures, due to the influence of solvent volatilization on the volume (V) ratio, the deviation of the measured gas solubility is generally large;

[0006] 2. The calculation of gas solubility is based on the ideal gas state equation (the ideal gas state equation assumes that the gas phase composition is pure raw material gas, which is a fast and simple calculation method under low temperature and low pressure conditions, and its accuracy can also meet the engineering requirements). However, under high temperature and high pressure conditions, the gas behavior has deviated far from the ideal gas state equation. In addition, the vapor pressure of the solvent in the gas phase in a high temperature system is not fully considered, and the accuracy of the calculated gas solubility is poor based on this.

[0007] In summary, it is necessary to develop an apparatus that can still accurately measure gas solubility under high temperature and high pressure, and this apparatus needs to be able to accurately measure the gas solubility in volatile solvent systems.

[0008] It should be noted that in the present invention, unless otherwise specified, the "high temperature" refers to: the test temperature > 100 °C (such as 120 °C, 200 °C, 300 °C, etc.) or the test temperature is close to the atmospheric boiling point or bubble point of the liquid solvent.

[0009] It should be noted that in the present invention, unless otherwise specified, the "high pressure" refers to: the test pressure ≥ 200 kPa, such as 500 kPa, 1000 kPa, 5000 kPa, etc.

[0010] It should be noted that in the present invention, when measuring the dissolution data of a gas in a liquid at a set temperature and a set pressure, unless otherwise specified, the "set temperature" is marked as T i , and the "set pressure" is marked as P i .

[0011] It should be noted that in the present invention, unless otherwise specified, the PR (Peng - Robinson, hereinafter referred to as PR) equation is the equation of state of a gas, and the PR equation is: In the formula: P is the pressure, T is the temperature, R is the gas constant, v is the molar volume, A is the characteristic parameter, and B is the characteristic parameter. Summary of the Invention

[0012] To achieve the above object, the present invention adopts the following technical solution: A device for measuring the solubility of a gas, comprising a phase equilibrium system, an analysis system, and a data processing system. The phase equilibrium system is connected to the analysis system, and the phase equilibrium system and the analysis system are respectively connected to the data processing system.

[0013] Among them, the phase equilibrium system includes a gas - phase collection container module, a temperature control module, a gas - liquid mixing container module, a first pressure sensor, a first temperature sensor, a second pressure sensor, and a second temperature sensor. The gas - phase collection container module and the gas - liquid mixing container module are connected to each other through a connecting pipe fitting. The temperature control module is used to control the temperature inside the gas - phase collection container module and the temperature inside the gas - liquid mixing container module. The detection ends of the first pressure sensor and the first temperature sensor are both connected to the gas - phase collection container module. The first pressure sensor is used to collect the internal pressure data of the gas - phase collection container module, and the first temperature sensor is used to collect the internal temperature data of the gas - phase collection container module. The detection ends of the second pressure sensor and the second temperature sensor are both connected to the gas - liquid mixing container module. The second pressure sensor is used to collect the internal pressure data of the gas - liquid mixing container module, and the second temperature sensor is used to collect the internal temperature data of the gas - liquid mixing container module. Moreover, the first pressure sensor, the first temperature sensor, the second pressure sensor, and the second temperature sensor are respectively communicatively connected to the data processing system.

[0014] Among them, the analysis system includes a gas chromatograph and a six-way valve. The analysis system can achieve automatic sampling, analysis, and data transmission of gas composition. The gas-liquid mixing container module and the gas chromatograph are connected through a six-way valve. The gas chromatograph and the data processing system are communicatively connected. The six-way valve realizes the extraction of the gas inside the gas-liquid mixing container module by switching the gas path. When the six-way valve is in the initial position, it connects the outlet of the gas-liquid mixing container module and the gas chromatograph. By rotating the valve body by 60°, the gas path is changed, so that the gas inside the gas-liquid mixing container module enters the gas chromatograph. This process utilizes the fast response characteristic of the six-way valve (such as the electronic needle valve opening in 0.8 seconds) to ensure the accuracy and efficiency of gas extraction. The six-way valve can also accurately introduce gas into the gas chromatograph through a quantitative loop and avoid the problem of gas-liquid entrainment.

[0015] In one or more embodiments, the data processing system includes a computer for processing data. The computer establishes a communicative connection with a first pressure sensor, a first temperature sensor, a second pressure sensor, a second temperature sensor, and a gas chromatograph through signal lines, thereby realizing the monitoring, collection, transmission, and processing of data such as temperature, pressure, and composition. The computer can record temperature and pressure data, and the computer is provided with a simple arithmetic unit for mathematical calculations. Through calculations, data information such as the temperature change amount and pressure change amount within any short time period can be obtained. The computer can perform human-computer interaction operations.

[0016] In one or more embodiments, the gas collection container module includes a gas storage tank, the gas-liquid mixing container module includes an equilibrium kettle, and the temperature control device includes a constant temperature box. The equilibrium kettle and the gas storage tank are both placed inside the constant temperature box. The constant temperature box can make the temperature fields inside the gas storage tank and the equilibrium kettle have no gradient distribution. To ensure the stable temperature of the constant temperature box, preferably, a heating rod and a thermocouple are provided inside the constant temperature box. The temperature inside the constant temperature box is adjusted through the heating rod, and the temperature inside the constant temperature box is monitored through the thermocouple.

[0017] In one or more embodiments, to improve the test efficiency of the device, the phase equilibrium system further includes a magnetic stirrer. A magnetic rotor driven by the magnetic stirrer is arranged inside the gas-liquid mixing container module. The role of the magnetic stirrer is to promote the rapid achievement of equilibrium in the dissolution of the gas inside the gas-liquid mixing container module.

[0018] In one or more embodiments, the phase equilibrium system further includes a vacuum pump, a first valve, a second valve, a third valve, and a fourth valve. The gas-phase collection container module is connected through the first valve and an intake pipeline for delivering the gas to be measured. The second valve is arranged on the connecting pipe fitting between the gas-phase collection container module and the gas-liquid mixing container module. The gas-liquid mixing container module is connected to the vacuum pump through the third valve. The gas-liquid mixing container module is connected to a six-way valve through the third valve and the fourth valve connected in series. To reduce the influence of the external environment on the phase equilibrium system, preferably, both the first valve and the third valve are one-way valves.

[0019] The device provided by the present invention can accurately measure the solubility of a gas in a volatile solvent, and this device can accurately measure the solubility of a gas in a solvent under high temperature and high pressure. For example, the gas can be any one of hydrogen, carbon monoxide, carbon dioxide, methane, butane, or nitrogen. For example, the solvent includes, but is not limited to, any one or at least two combinations of toluene, water, alcohol liquids, or ester liquids. Typical but non-limiting combinations include: the combination of toluene and water, the combination of alcohol liquids and ester liquids, the combination of toluene, water, alcohol liquids, and ester liquids, etc.

[0020] A method for measuring the solubility of a gas using the above device includes the following steps:

[0021] (1) Calibration process of fixed volume: Calibrate the volumes of the gas-phase collection container module and the gas-liquid mixing container module to obtain the accurate volumes V1 and V2 of the gas-phase collection container module and the gas-liquid mixing container module respectively;

[0022] (2) Feeding and vacuum pumping process: Weigh a certain mass m of a liquid solvent (it should be noted that the values of the density ρ and the molar mass M of this liquid solvent are both known), add it to the gas-liquid mixing container module, and then perform repeated vacuum pumping on the gas-phase collection container module, the gas-liquid mixing container module, and the connecting pipe fitting at least three times;

[0023] (3) Gas filling and heating process: Fill and seal a certain pressure of the gas to be measured inside the gas-phase collection container module, turn on the temperature control module for heating, use the first pressure sensor and the first temperature sensor to collect and record the changes in the pressure P1 and the temperature T1 inside the gas-phase collection container module in real time, and send the collected data to the data processing system; wait until the temperature T1 inside the gas-phase collection container module is stable at the set temperature T i After that, fill and seal a part of the gas to be measured inside the gas-phase collection container module into the gas-liquid mixing container module (by controlling the filling amount of the gas to be measured to make the pressure P2 inside the gas-liquid mixing container module reach the set pressure P i) The second pressure sensor and the second temperature sensor are used to collect and record the changes in the pressure P2 and temperature T2 inside the gas-liquid mixing container module in real time, and the collected data is sent to the data processing system;

[0024] (4) Gas composition analysis: After the temperature T2 inside the gas-liquid mixing container module stabilizes at the set temperature T i (the measured gas solubility data is the gas solubility of the gas to be measured at this set temperature T i ), the six-way valve of the analysis system is opened to sample the gas phase inside the gas-liquid mixing container module, and the gas phase inside the gas-liquid mixing container module is introduced into the gas chromatograph of the analysis system through the six-way valve of the analysis system for analysis, and the analysis data of the gas chromatograph is sent to the data processing system;

[0025] (5) Automatic data processing and output: The data processing system performs real-time calculations on the collected data and outputs the gas solubility data. Since the direct measurement results of the device are temperature (T1 and T2), pressure (P1 and P2), and the composition data measured by the chromatograph obtained through direct transmission, the data processing system processes the measurement results and converts them into the mole fraction of the gas in the liquid to represent the gas solubility through an embedded calculation formula.

[0026] The beneficial effects of the present invention are as follows: The device provided by the present invention can accurately measure the gas solubility under high temperature and high pressure, and the device can accurately measure the gas solubility of a volatile solvent system. Using the device provided by the present invention to measure the gas solubility expands the measurement accuracy of the static method for the gas solubility of a volatile solvent system, realizes the full-automatic measurement of unattended high-pressure gas solubility data, and improves the efficiency of gas solubility measurement. Description of the Drawings

[0027] The drawings further illustrate the present invention, but the embodiments in the drawings do not constitute any limitation to the present invention.

[0028] Figure 1 It is a schematic structural diagram of the device provided by the embodiment of the present invention.

[0029] Figure 2 It is a schematic structural diagram of the device provided by the embodiment of the present invention.

[0030] Figure 3 It is a data processing logic diagram for the process of measuring the gas solubility using the device provided by the embodiment of the present invention.

[0031] Figure 4 It is a schematic diagram of the solubility data of CO2 in ethylene carbonate measured using the device provided by the embodiment of the present invention.

[0032] Among them,Figure 1-2 The reference numerals are as follows: 1 - phase equilibrium system; 2 - analysis system; 3 - data processing system; 4 - physical parameter input signal line; 5 - first signal line; 6 - gas pipeline; 7 - second signal line; 8 - thermostatic chamber; 9 - gas storage tank; 10 - equilibrium kettle; 11 - magnetic stirrer; 12 - equilibrium valve; 13 - temperature sensor; 14 - pressure sensor; 15 - gas pipeline; 16 - six-way valve; 17 - chromatographic column; 18 - chromatographic column oven; 19 - temperature and pressure signal line; 20 - composition analysis signal line; 21 - computer; 22 - vacuum pump.

[0033] Among them, Figure 4 The reference numerals are as follows: m is the added mass of the solvent; V 1～2 are the volumes of the gas storage tank and the equilibrium kettle respectively; P1 and T1 are the measured values of the pressure and temperature of the gas storage tank; P2 and T2 are the measured values of the pressure and temperature of the equilibrium kettle; x G is the gas analysis result, that is, the content of the gas to be measured in the gas phase; △V m is the change in partial molar volume of the gas before and after charging the gas storage tank and the equilibrium kettle; △n and △n’ are the ideal dissolved amount and the true dissolved amount respectively; n L ’ is the true liquid-phase molar amount of the solvent; a is the solubility output value of the gas to be measured in the solvent; Equations 1 - 5 are the calculation correlation formulas involved in the process of measuring the solubility of high-pressure gas. Specific embodiments

[0034] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] As Figure 1 shown, the device provided by the embodiment of the present invention includes a phase equilibrium system 1, an analysis system 2, and a data processing system 3. The phase equilibrium system 1 is connected to the analysis system 2 through a gas pipeline 6, and the phase equilibrium system 1 is connected to the data processing system 3 through a first signal line 5. The analysis system 2 is connected to the data processing system 3 through a second signal line 7. As a further improvement of the present invention, the device of this embodiment further includes an operator input end, and the operator input end is connected to the data processing system 3 through a physical parameter input signal line 4. Before using the device to measure the solubility of the gas to be measured, the operator can manually input relevant data of the gas to be measured G and / or the liquid solvent L to the data processing system 3 through the operator input end. The data processing system 3 is used to output the value of the solubility α of the gas to be measured.

[0036] As Figure 2 shown, the specific structure of the device provided by the embodiment of the present invention is as follows:

[0037] The phase equilibrium system 1 includes a gas-phase collection container module, a temperature control module, a gas-liquid mixing container module, a magnetic stirrer 11, a balance valve 12, a temperature sensor 13, a pressure sensor 14, a gas-phase pipeline 15, and a vacuum pump 22. The gas-phase collection container module is a gas storage tank 9, the temperature control module is a constant temperature oven 8, and the gas-liquid mixing container module is a balance kettle 10. The analysis system 2 includes a six-way valve 16 and a gas chromatograph, and the gas chromatograph includes a chromatographic column 17 and a chromatographic column oven 18. The data processing system 3 includes a computer 21 with a function program for data acquisition, processing, and gas solubility calculation. The computer 21 establishes a communication connection with the temperature sensor 13 and the pressure sensor 14 through a temperature and pressure signal line 19, and the computer 21 establishes a communication connection with the gas chromatograph through a composition analysis signal line 20.

[0038] The balance kettle 10 and the gas storage tank 9 are placed in the constant temperature oven 8. The balance kettle 10 and the gas storage tank 9 are connected by a connecting pipe fitting, and the balance valve 12 is arranged on the connecting pipe fitting. The balance kettle 10 is connected to the gas chromatograph through the gas-phase pipeline 15, and the six-way valve 16 is arranged on the gas-phase pipeline 15.

[0039] For the convenience of data acquisition and processing, both the temperature sensor 13 and the pressure sensor 14 include two sets. The temperature sensor 13 includes a first temperature sensor and a second temperature sensor, and the pressure sensor 14 includes a first pressure sensor and a second pressure sensor. The detection ends of the first pressure sensor and the first temperature sensor are both arranged inside the gas storage tank 9, and the detection ends of the second pressure sensor and the second temperature sensor are both arranged inside the balance kettle 10. The first pressure sensor is used for the internal pressure data of the gas storage tank 9, the first temperature sensor is used for collecting the internal temperature data of the gas storage tank 9, the second pressure sensor is used for collecting the internal pressure data of the balance kettle 10, and the second temperature sensor is used for collecting the internal temperature data of the balance kettle 10. It should be noted that the display instruments of the temperature sensor 13 and the pressure sensor 14 are both arranged outside the constant temperature oven 8.

[0040] The gas storage tank 9 is also connected to an inlet pipeline, and the inlet pipeline is used to fill the gas storage tank 9 with the gas to be measured. A one-way valve is arranged on the inlet pipeline. The balance kettle 10 is connected to the vacuum pump 22 through the gas-phase pipeline 15, and the vacuum pump 22 is used to evacuate the gas storage tank 9, the balance kettle 10, and the connecting pipe fitting. A one-way valve and a two-way valve are arranged in series on the gas-phase pipeline 15. The one-way valve is arranged between the balance kettle 10 and the vacuum pump 22, and the series-connected one-way valve and two-way valve are arranged between the balance kettle 10 and the six-way valve 16.

[0041] The magnetic stirrer 11 is located at the lower part of the thermostatic chamber 8. A control panel is provided on the outer surface of the thermostatic chamber 8, which is used to display the internal temperature of the thermostatic chamber 8 and control the thermostatic chamber 8. To ensure the stable temperature of the thermostatic chamber 8, a heating rod and a thermocouple are arranged in the thermostatic chamber 8. The temperature in the thermostatic chamber 8 is adjusted by the heating rod, and the temperature in the thermostatic chamber 8 is monitored by the attached thermocouple. A sealed heat-insulating layer is arranged between the magnetic stirrer 11 and the thermostatic chamber 8.

[0042] The thermostatic chamber 8 is used to provide a high-temperature heat source, which can effectively increase the measured temperature range. The pressure sensor 14 is used to monitor the temperature and pressure changes inside the gas storage tank 9 and the equilibrium kettle 10, and the temperature and pressure are monitored and transmitted in real time through the temperature and pressure signal line 19; the gas-phase composition inside the equilibrium kettle 10 is detected and analyzed by using the gas-phase pipeline 15, the six-way valve 16, the chromatographic column 17 and the chromatographic column oven 18, and the analysis results are transmitted to the computer 21 through the composition analysis signal line 20 to complete the data processing, and then the automatic calculation and output of the gas solubility data are realized.

[0043] A method for measuring the gas solubility by using the device provided by the embodiment of the present invention includes the following steps:

[0044] (1) Calibration process of fixed volume: The volumes of the gas storage tank 9 and the equilibrium kettle 10 are calibrated respectively, and the accurate volumes V1 and V2 of the gas storage tank 9 and the equilibrium kettle 10 are obtained respectively;

[0045] (2) Feeding and vacuum pumping process: Weigh a certain mass m of liquid solvent (the density ρ of the liquid solvent is known) and add it into the equilibrium kettle 10, and then use the vacuum pump 22 to repeatedly pump the gas storage tank 9, the equilibrium kettle 10 and the connecting pipe fittings three times;

[0046] (3) Gas filling and heating process: Fill and seal a certain pressure of the gas to be measured into the gas storage tank 9, turn on the thermostatic chamber 8 for heating, use the first pressure sensor and the first temperature sensor to collect and record the changes of the pressure P1 and the temperature T1 inside the gas storage tank 9 in real time, and send the collected data to the computer 21; wait until the temperature T1 is stable at the set temperature T i After that, part of the gas to be measured in the gas storage tank 9 is filled and sealed into the equilibrium kettle 10 (by controlling the filling amount of the gas to be measured so that the pressure P2 in the equilibrium kettle 10 reaches the set pressure P i ), use the second pressure sensor and the second temperature sensor to collect and record the changes of the pressure P2 and the temperature T2 inside the equilibrium kettle 10 in real time, and send the collected data to the computer 21;

[0047] (4) Gas-phase composition analysis: Wait until the temperature T2 is stable at the set temperature T iAfter that, the six-way valve 16 of the analysis system is opened to sample the gas phase inside the equilibrium kettle 10, and the gas phase inside the equilibrium kettle 10 is introduced into the gas chromatograph through the six-way valve 16 for analysis, and the analysis data is sent by the gas chromatograph to the computer 21;

[0048] (5) Automatic data processing and output: The computer 21 performs real-time calculation on the collected data and outputs the gas solubility data.

[0049] The data processing logic in the process of measuring gas solubility using the device provided in the embodiment of the present invention is as Figure 3 shown. The gas solubility is calculated through the state parameters of the phase equilibrium system and the physical and chemical characteristic parameters of the gas-liquid phase. The phase equilibrium data of the volatile solvent system is corrected through the coupled analysis system, breaking through the technical problems of difficult automatic determination and large measurement deviation of gas solubility data in the volatile solvent system.

[0050] Among them Figure 3 the specific forms of correlation expressions 1-5 are as follows:

[0051] △V m =f(T i ,ΔP i ,m) Equation 1

[0052] △n=f(P,T,△V) Equation 2

[0053] △n′=f(△n,x G )=△n×x G Equation 3

[0054]

[0055] Among them, by collecting the change values of the pressures of the gas storage tank 9 and the equilibrium kettle 10 and the temperature values after stabilization, the changes in the gas amounts (△V m and △n) of the gas storage tank 9 and the equilibrium kettle 10 before and after gas filling are calculated using correlation expressions 1 and 2; then, the gas phase composition data x G inside the equilibrium kettle 10 obtained by the gas chromatograph and Equation 3 are used to correct the ideal dissolved amount △n to obtain the true dissolved amount △n’, and finally, the true solubility a of the gas to be measured is obtained using Equations 4 and 5.

[0056] Among them, △P represents the difference in the pressure changes of the gas storage tank and the equilibrium tank, and the calculation expressions for the pressure changes of the gas storage tank and the equilibrium tank are Equations 6 and 7 respectively:

[0057] ΔP1=P 1初始 -P 1稳定 Equation 6

[0058] ΔP2=P 2稳定 -P2初始 Formula 7

[0059] To further illustrate how to use the device provided by the embodiments of the present invention to measure the gas solubility, the solubility of methane in deionized water is measured using this device here. The specific steps are as follows:

[0060] Step 1: Calibrate the volumes of the gas storage tank 9 and the equilibrium kettle 10 respectively, and obtain the accurate volumes V1 and V2 of the gas storage tank 9 and the equilibrium kettle 10 respectively;

[0061] Step 2: Weigh deionized water with a mass of m (the density ρ and molar mass M of deionized water are known) and add it to the equilibrium kettle 10. Then, use the vacuum pump 22 to repeatedly evacuate the gas storage tank 9, the equilibrium kettle 10, and the connecting pipe fittings three times;

[0062] Step 3: At room temperature, fill the inside of the gas storage tank 9 with methane at a certain pressure and seal it. Turn on the thermostatic chamber 8 to heat until the value of the temperature T1 inside the gas storage tank 9 collected and recorded in real time by the first temperature sensor is stable at the set temperature T i (i.e., T1 = T i ) After that, the first pressure sensor collects and records the value of the pressure P1 inside the gas storage tank 9 until the value of P1 is stable at P 1初始 , and the second pressure sensor collects and records the value of the pressure P2 inside the equilibrium kettle 10 until the value of P2 is stable at P 2初始 ;

[0063] Step 4: Open the balance valve 12, and fill the methane in the gas storage tank 9 into the equilibrium kettle 10 through the connecting pipe fittings until the value of the pressure P2 inside the equilibrium kettle 10 reaches the set pressure P i After that, close the balance valve 12 to stop filling methane into the equilibrium kettle 10, seal the equilibrium kettle 10, and use the thermostatic chamber 8 to stabilize the value of the temperature T2 inside the equilibrium kettle 10 at the set temperature T i (i.e., T2 = T i ) The first pressure sensor collects and records the value of the pressure P1 inside the gas storage tank 9 until the value of P1 is stable at P 1稳定 , and the second pressure sensor collects and records the value of the pressure P2 inside the equilibrium kettle 10 until the value of P2 is stable at P 2稳定 ;

[0064] Step 5: Open the six-way valve 16 of the analysis system to sample the gas phase inside the equilibrium kettle 10, and introduce the gas phase inside the equilibrium kettle 10 into the gas chromatograph through the six-way valve 16 for analysis to obtain the content x of methane in the gas phase CH4 ;

[0065] Step 6: The computer 21 calculates the solubility of methane in deionized water through the collected values (including V1, V2, T1, T2, P1初始 , P 2初始 , P 1稳定 , P 2稳定 , x CH4 ) perform real-time calculation and output the gas solubility data α. The calculation process is as follows:

[0066] According to ΔP1 = P 1初始 - P 1稳定 (i.e., Equation 6), input P 1初始 and P 1稳定 , and obtain △P1;

[0067] According to ΔP2 = P 2稳定 - P 2初始 (i.e., Equation 7), input P 2初始 and P 2稳定 , and obtain △P2;

[0068] According to (i.e., Equation 1, where R is the gas constant corresponding to methane, and A and B are the characteristic parameters of the PR equation of methane, both of which can be obtained by referring to chemical engineering handbooks or thermodynamics books, T = T i ), input △P1 to obtain △V1, and input △P2 to obtain △V2;

[0069] According to (i.e., Equation 2), input △V1, and obtain △n1;

[0070] According to (i.e., Equation 2), input △V2, and obtain △n2;

[0071] According to △n = Δn1 - Δn2, input △n1 and △n2 to obtain △n;

[0072] When the liquid to be measured is volatile, determine the composition x CH4 of the key components of the equilibrium kettle gas by chromatography, then the actual dissolved gas amount is:

[0073] According to △n′ = Δn1 - Δn2 × x CH4 (i.e., Equation 3), input △n1, △n2 and x CH4 to obtain △n′;

[0074] It can be known that when and only when x CH4 → 1, △n′ → △n;

[0075] According to (i.e., Equation 4), input m, M, △n2 and x CH4 to obtain n L ′;

[0076] According to (i.e., Equation 5), input △n and n L'Get the set temperature T i and set pressure P i The solubility of methane in deionized water is α.

[0077] The operating temperature range of the thermostat 8 of the device provided in the embodiment of the present invention is 30-300°C, and the temperature control accuracy is 0.1°C; the magnetic stirrer 11 of the device can provide heat autonomously, with a tolerance temperature of 400°C and a rotation speed of 0-3000 rpm; the pressure measuring range of the first pressure sensor and the pressure measuring range of the second pressure sensor are both -101.0kPa-5000kPa, with an accuracy of 0.1kPa; the temperature measuring range of the first temperature sensor and the temperature measuring range of the second temperature sensor are both 0°C-1000°C, with an accuracy of 0.01°C. The data acquisition and processing and gas solubility calculation function program is stored in the readable storage medium of the computer 21, and the computer program is executed by the processor to realize the determination of gas solubility. In order to realize the monitoring, acquisition and processing of gas solubility data, the frequency of collecting data from the temperature sensor 13, the pressure sensor 14 and the gas chromatograph by the computer 21 is 1 time / minute to 60 times / minute, and the delay of collecting data is no more than 0.1 milliseconds.

[0078] For further explanation, the solubility of carbon dioxide (CO2) in ethylene carbonate (EC) is measured using the device provided in the embodiment of the present invention. The specific operation process is as follows:

[0079] Step 1: Use the volumetric method to measure the gas storage tank 9 and the balance kettle 10 to obtain the volumes V1 and V2 of the gas storage tank and the balance kettle respectively;

[0080] Step 2, accurately weighing a mass m of ethylene carbonate solvent (density ρ and molar mass M of ethylene carbonate are known) and adding it to the equilibrium kettle 10, and using a vacuum pump 22 to repeatedly evacuate the gas storage tank 9, the equilibrium kettle 10 and the connecting pipes three times;

[0081] Step 3: Fill the gas tank 9 with a certain pressure of CO2 and seal it, and turn on the thermostat 8 to heat it until the first temperature sensor collects and records the temperature T1 inside the gas tank 9 in real time and stabilizes to the set temperature T i (i.e. T1 = T i ), the first pressure sensor collects and records the value of the pressure P1 inside the gas storage tank 9 in real time until the value of P1 stabilizes to P 1初始 The second pressure sensor collects and records the value of the pressure P2 inside the equilibrium kettle 10 in real time until the value of P2 stabilizes to P 2初始 , and T1, P 1初始 and P 2初始 The value is transmitted to the computer 21 via the temperature and pressure signal line 19;

[0082] Step 4: Open the balance valve 12, and fill the CO2 in the gas storage tank 9 into the balance kettle 10 through the connecting pipe fittings until the value of the pressure P2 inside the balance kettle 10 reaches the set pressure P. i Then close the balance valve 12 to stop filling CO2 into the balance kettle 10, seal the balance kettle 10, and use the constant temperature box 8 to stabilize the value of the temperature T2 inside the balance kettle 10 at the set temperature T. i (That is, T2 = T. i ) The first pressure sensor collects and records the value of the pressure P1 inside the gas storage tank 9 in real time until the value of P1 stabilizes at P. 1稳定 The second pressure sensor collects and records the value of the pressure P2 inside the balance kettle 10 in real time until the value of P2 stabilizes at P. 2稳定 And the values of T2, P 1稳定 and P 2稳定 are transmitted to the computer 21 through the temperature and pressure signal line 19.

[0083] Step 5: Open the six-way valve 16 of the analysis system to sample the gas phase inside the balance kettle 10, and introduce the gas phase inside the balance kettle 10 into the gas chromatograph through the six-way valve 16 for analysis to obtain the content x of carbon dioxide in the gas phase. CO2 The analysis result x CO2 is transmitted to the computer 21 through the composition analysis signal line 20.

[0084] Step 6: In the computer 21, use the data acquisition program to collect the collected values (including V1, V2, T1, T2, P 1初始 , P 2初始 , P 1稳定 , P 2稳定 , P CO2 , x i ) to calculate the solubility data a of CO2 in EC at 50 °C (that is, T Figure 4 = 50 °C) through Formulas 1 - 6. The specific test results are shown in Table 1 and

[0085] According to ΔP1 = P 1初始 - P 1稳定 (that is, Formula 6), input P 1初始 and P 1稳定 to obtain △P1.

[0086] According to ΔP2 = P 2稳定 - P 2初始 (that is, Formula 7), input P 2初始 and P 2稳定 to obtain △P2.

[0087] According to (i.e., Equation 1, where R is the gas constant corresponding to carbon dioxide, and A and B are the characteristic parameters of the PR equation for carbon dioxide, which can be obtained by referring to chemical engineering handbooks or thermodynamics books. T = T i ), input ΔP1 to obtain ΔV1, and input ΔP2 to obtain ΔV2;

[0088] According to (i.e., Equation 2), input ΔV1 to obtain Δn1;

[0089] According to (i.e., Equation 2), input ΔV2 to obtain Δn2;

[0090] According to Δn = Δn1 - Δn2, input Δn1 and Δn2 to obtain Δn;

[0091] When the liquid to be measured is volatile, the composition x of the key components in the equilibrium kettle gas is determined by chromatography CH4 , then the true amount of dissolved gas is:

[0092] According to Δn′ = Δn1 - Δn2 × x CO2 (i.e., Equation 3), input Δn1, Δn2, and x CO2 to obtain Δn′;

[0093] It can be seen that when and only when x CO2 → 1, Δn′ → Δn;

[0094] According to (i.e., Equation 4), input m, M, Δn2, and x CO2 to obtain n L ′;

[0095] According to (i.e., Equation 5), input Δn and n L ′ to obtain the solubility α of carbon dioxide in ethylene carbonate solvent at the set temperature T i and the set pressure P i .

[0096] Among them, Equation 2 and Equation 3 are used to calculate the volume and molar amount of the gas dissolved in the equilibrium kettle 10, mainly representing the ideal state CO2 volume and molar amount in the equilibrium kettle 10 without considering solvent volatilization after inflation; Equation 4 and Equation 5 are the true gas dissolved molar amount and the true liquid molar amount in the equilibrium kettle corrected by using the actual composition of the gas phase CO2 obtained by the analysis system.

[0097] Table 1. Device test results of CO2 in ethylene carbonate

[0098] <![CDATA[T i (℃)]]> <![CDATA[P i (kPa.A)]]> <![CDATA[a(CO2)]]> 50 0 0 50 397.6 0.02297 50 826.9 0.04328 50 1291.7 0.06374 50 1507.1 0.07309 50 1850.2 0.08733 50 2080.3 0.09687 50 2161.0 0.10085

[0099] In this embodiment, the mainly used method in the measurement process is the modified static method. By utilizing the changes in P, V, and T of the gas during the dissolution process and the composition of the real gas, the solubility results of the volatile solvent system are corrected, enabling the convenient measurement, automatic monitoring, recording, and processing of gas solubility data under high temperature and high pressure conditions.

[0100] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0101] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. An apparatus for measuring the solubility of a gas, comprising a phase equilibrium system, an analysis system, and a data processing system. The phase equilibrium system is connected to the analysis system, and the phase equilibrium system and the analysis system are respectively connected to the data processing system. It is characterized in that: The equilibrium system includes a gas-phase collection container module, a temperature control module, a gas-liquid mixing container module, a first pressure sensor, a first temperature sensor, a second pressure sensor, and a second temperature sensor. The gas-phase collection container module and the gas-liquid mixing container module are connected to each other through a connecting pipe fitting. The temperature control module is used to control the temperature inside the gas-phase collection container module and the temperature inside the gas-liquid mixing container module. The detection ends of the first pressure sensor and the first temperature sensor are both connected to the gas-phase collection container module. The detection ends of the second pressure sensor and the second temperature sensor are both connected to the gas-liquid mixing container module. The first pressure sensor, the first temperature sensor, the second pressure sensor, and the second temperature sensor are respectively communicatively connected to the data processing system; The analysis system includes a gas chromatograph and a six-way valve. The gas-liquid mixing container module is connected to the gas chromatograph through the six-way valve.

2. The device according to claim 1, characterized in that: The data processing system includes a computer for processing data. The computer establishes a communication connection with the first pressure sensor, the first temperature sensor, the second pressure sensor, the second temperature sensor, and the gas chromatograph through signal lines.

3. The device according to claim 1, wherein: The gas-phase collection container module includes a gas storage tank, the gas-liquid mixing container module includes an equilibrium kettle, the temperature control device includes a constant temperature box, the equilibrium kettle and the gas storage tank are both placed in the constant temperature box, and a heating rod and a thermocouple are arranged inside the constant temperature box.

4. The device according to claim 1, characterized in that: The phase equilibrium system further includes a magnetic stirrer, and a magnetic rotor driven by the magnetic stirrer is arranged inside the gas-liquid mixing container module.

5. The device according to claim 1, characterized in that: The phase equilibrium system further includes a vacuum pump, a first valve, a second valve, a third valve, and a fourth valve. The gas-phase collection container module is connected to an intake pipe for conveying the gas to be measured through the first valve. The second valve is arranged on the connecting pipe fitting. The gas-liquid mixing container module is connected to the vacuum pump through the third valve. The gas-liquid mixing container module is connected to the six-way valve through the third valve and the fourth valve connected in series.

6. The device according to claim 5, characterized in that: Both the first valve and the third valve are one-way valves.

7. The apparatus according to claim 6, characterized in that: The pressure measurement ranges of the first pressure sensor and the second pressure sensor are both -101.0 kPa to 5000 kPa; The temperature measurement ranges of the first temperature sensor and the second temperature sensor are both 0 °C to 1000 °C.

8. A method for measuring the solubility of a gas, characterized in that: The method is implemented by the apparatus according to any one of claims 1-7.

9. The method according to claim 8, characterized in that: The gas solubility is the solubility of the gas in the liquid solvent at temperature T i and pressure P i ; The method includes the following steps: Step 1: Calibrate the volumes of the gas collection container module and the gas-liquid mixing container module to obtain the volumes V1 and V2 of the gas collection container module and the gas-liquid mixing container module respectively; Step 2: Weigh a liquid solvent with a mass of m and add it to the gas-liquid mixing container module, and then perform vacuum pumping on the gas collection container module, the gas-liquid mixing container module, and the connecting pipe fittings at least three times repeatedly; Step 3: Fill the inside of the gas collection container module with the gas and seal it, turn on the temperature control module to heat the gas collection container module and the gas-liquid mixing container module. When the temperature data collected by the first temperature sensor is stable at T i , the pressure data collected by the first pressure sensor is stable at P 1初始 and the pressure data collected by the second pressure sensor is stable at P 2初始 , introduce the gas in the gas collection container module into the gas-liquid mixing container module through the connecting pipe fittings and seal it. When the value collected by the second pressure sensor reaches P i , stop introducing the gas in the gas collection container module into the gas-liquid mixing container module; Step 4. When the temperature data collected by the second temperature sensor is stabilized at T i , the pressure data collected by the first pressure sensor is stabilized at P 1稳定 and the pressure data collected by the second pressure sensor is stabilized at P 2稳定 , open the six-way valve of the analysis system to introduce the gas phase inside the gas-liquid mixing container module into the chromatograph of the analysis system for analysis, and obtain the content data x of the gas in the gas phase G ; Step 5: The first pressure sensor, the first temperature sensor, the second pressure sensor, the second temperature sensor, and the gas chromatograph send the collected data to the data processing system for data processing, and the data processing system outputs the gas solubility data α.

10. The method according to claim 9, wherein The process of data processing in Step 5 includes: According to ΔP1 = P 1初始 - P 1稳定 , input P 1初始 and P 1稳定 , and obtain ΔP1; According to ΔP2 = P 2稳定 - P 2初始 , input P 2初始 and P 2稳定 , to obtain ΔP2; According to where R is the gas constant corresponding to the gas, A and B are the characteristic parameters of the PR equation of the gas, T = T i , input ΔP1 to obtain ΔV1, and input ΔP2 to obtain ΔV2; According to Input △V1 to obtain △n1; According to where ρ is the numerical value of the density of the liquid solvent, input ΔV2 to obtain Δn2; According to △n = Δn1 - Δn2, input Δn1 and Δn2 to obtain △n; According to △n′ = Δn1 - Δn2×x G , input △n1, △n2 and x G to obtain △n′; According to where M is the value of the molar mass M of the liquid solvent, input m, M, Δn2 and x G to obtain n L '; According to input △n and n L ′ to obtain the gas solubility data α.

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