Binary gas-liquid equilibrium determination method for explosive boiling substance composed of high-boiling-point substance and water

Abstract

The invention belongs to the technical field of binary gas-liquid equilibrium determination of explosive and boiling substances, and discloses a binary gas-liquid equilibrium determination method of an explosive and boiling substance composed of a high-boiling-point substance and water. According to the invention, the influence of bumping on sampling is avoided to the greatest extent by improving a common testing instrument and a measuring method, so that the universal measuring method is changed to be applicable to binary gas-liquid equilibrium testing of high-boiling-point substances and water. The basic theory of separating two substances in the high-boiling-point substances is supplemented, an important theoretical basis is provided for amplified production, and the trial and error cost of experience amplification is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of binary gas-liquid equilibrium determination of explosively boiling substances, and in particular to a binary gas-liquid equilibrium determination method of explosively boiling substances composed of high-boiling-point substances and water. Background Art

[0002] Most existing gas-liquid equilibrium determination methods use an integrated gas-liquid equilibrium kettle for sampling and determination, but most of them are suitable for two substances with low and similar boiling points. The temperature at which high-boiling-point substances and water reach gas-liquid equilibrium is higher than that of water. Water has a large expansion coefficient, which can easily cause violent boiling. Violent boiling causes back mixing at the liquid sampling position and even the gas sampling position, making the experiment impossible to carry out. Usually, this violent boiling cannot be suppressed by zeolites. For aqueous samples, violent boiling is already very intense at low pressure. If the sample is a high-boiling-point substance that requires a higher heating temperature, the experiment is even more difficult to carry out. Therefore, it is of great significance to develop a binary gas-liquid equilibrium determination method suitable for explosively boiling substances composed of high-boiling-point substances and water that can avoid the influence of violent boiling on sampling. Summary of the invention

[0003] In view of this, the present invention provides a binary gas-liquid equilibrium determination method for explosively boiling substances composed of high-boiling point substances and water, so as to solve the problem that the existing gas-liquid equilibrium determination method is not suitable for explosively boiling substances composed of high-boiling point substances and water, and explosive boiling is prone to occur during the determination process, affecting sampling.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] The present invention provides a method for determining binary gas-liquid equilibrium of an explosively boiling substance composed of a high-boiling-point substance and water, comprising the following steps:

[0006] (1) The test solution composed of the high boiling point substance and water is prepared into 10 test samples at mass concentrations of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% respectively;

[0007] (2) placing the 10 samples obtained in step (1) in a gas-liquid equilibrium kettle for measurement to obtain the equilibrium temperature, and after the measurement, taking liquid phase samples and gas phase samples to obtain liquid phase samples and gas phase samples;

[0008] (3) analyzing the composition of the liquid sample and the gas sample obtained in step (2) by using a gas chromatography external standard method, listing a comparison table of mass ratio, equilibrium temperature, and sample composition, finding the vapor pressure according to the equilibrium temperature, calculating the activity coefficient based on Raoult's law, calculating the theoretical value of the sample by using the Wilson equation, and obtaining a binary gas-liquid equilibrium curve by using Aspen fitting;

[0009] The gas-liquid balance kettle comprises a heating sleeve, kettle liquid, an air guide tube, a riot ball, a thermometer sleeve, a condenser, a liquid phase sampling port, a vapor phase liquid sampling port and a sealing gasket; the sealing gasket comprises a through hole, and the diameter of the through hole is ≤0.5mm.

[0010] Preferably, the high boiling point substance is 1,5-pentanediamine or 1,6-hexanediamine.

[0011] Preferably, in step (2), the pressure measured is independently 10 to 101.3 kPa.

[0012] Preferably, in step (2), the specific steps of the determination are independent: placing the 10 samples to be tested obtained in step (1) in a gas-liquid equilibrium kettle respectively, setting the pressure of the measurement, and increasing the temperature of the samples to be tested until the samples to be tested boil; recording the temperature after heating stabilizes, which is the equilibrium temperature; and then performing liquid phase sampling and gas phase sampling after 20 to 40 minutes.

[0013] Preferably, in the step (2), the gas-liquid equilibrium kettle is dried before each sample is measured; the drying temperature is independently 40 to 80°C.

[0014] Preferably, in step (2), the heating is stabilized so that the temperature of the gas-liquid equilibrium kettle does not change within 8 to 12 minutes after the measured pressure is increased again.

[0015] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention improves the commonly used test instruments and determination methods, avoids the influence of bumping on sampling to the greatest extent, and changes the commonly used determination method to be applicable to binary gas-liquid equilibrium test of high-boiling-point substances and water. The basic theory of separation of two substances in high-boiling-point substances is supplemented, providing an important theoretical basis for scale-up production and reducing the trial-and-error cost of empirical scale-up. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the gas-liquid equilibrium kettle of the present invention;

[0019] Figure 2 This is the binary gas-liquid equilibrium curve of 1,5-pentanediamine and water described in Example 1. DETAILED DESCRIPTION

[0020] The present invention provides a method for determining binary gas-liquid equilibrium of an explosively boiling substance composed of a high-boiling-point substance and water, comprising the following steps:

[0021] (1) The test solution composed of the high boiling point substance and water is prepared into 10 test samples at mass concentrations of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% respectively;

[0022] (2) placing the 10 samples obtained in step (1) in a gas-liquid equilibrium kettle for measurement to obtain the equilibrium temperature, and after the measurement, taking liquid phase samples and gas phase samples to obtain liquid phase samples and gas phase samples;

[0023] (3) analyzing the composition of the liquid sample and the gas sample obtained in step (2) by using a gas chromatography external standard method, listing a comparison table of mass ratio, equilibrium temperature, and sample composition, finding the vapor pressure according to the equilibrium temperature, calculating the activity coefficient based on Raoult's law, calculating the theoretical value of the sample by using the Wilson equation, and obtaining a binary gas-liquid equilibrium curve by using Aspen fitting;

[0024] The gas-liquid balance kettle comprises a heating sleeve, kettle liquid, an air guide tube, a riot ball, a thermometer sleeve, a condenser, a liquid phase sampling port, a vapor phase liquid sampling port and a sealing gasket; the sealing gasket comprises a through hole, the diameter of the through hole is ≤0.5mm; the sealing gasket is located in the liquid phase sampling port and the vapor phase sampling port.

[0025] The sealing gasket of the gas-liquid balance kettle of the present invention is provided with through holes to maintain the vacuum pump to work continuously rather than intermittently, to maintain the continuous generation of bubbles and to avoid greater violent boiling.

[0026] The invention can avoid the occurrence of back mixing by adding an anti-riot ball and extending the distance from the bottom of the kettle to the sampling position.

[0027] In the present invention, the high boiling point substance is preferably 1,5-pentanediamine or 1,6-hexanediamine.

[0028] In step (2) of the present invention, the measured pressure is independently preferably 10 to 101.3 kPa, more preferably 40 to 70 kPa.

[0029] In step (2) of the present invention, the specific steps of the determination are independent: placing the 10 samples to be tested obtained in step (1) in a gas-liquid equilibrium kettle respectively, setting the pressure of the measurement, and increasing the temperature of the samples to be tested until the samples to be tested boil; recording the temperature after heating stabilizes, which is the equilibrium temperature; and then performing liquid phase sampling and gas phase sampling after 20 to 40 minutes.

[0030] In step (2) of the present invention, the gas-liquid equilibrium kettle is dried before each sample is measured; the drying temperature is independently preferably 40-80°C, more preferably 50-70°C, and more preferably 60-65°C.

[0031] In step (2) of the present invention, heating stabilization means that the temperature of the gas-liquid equilibrium kettle does not change within 8 to 12 minutes after the measured pressure is increased again.

[0032] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0033] The gas-liquid equilibrium reactor used in the following examples is as follows: Figure 1 As shown, it includes a heating sleeve, kettle liquid, an air guide tube, a riot ball, a thermometer sleeve, a condenser, a liquid phase sampling port, a vapor phase liquid sampling port and a sealing gasket; the sealing gasket includes a through hole, and the diameter of the through hole is ≤0.5mm.

[0034] Example 1

[0035] A Tokyo Rika n-1300 precision pressure controller was used; the gas-liquid balance kettle was a custom-made one, and the distance between the tower kettle liquid and the sampling port was set so that when the kettle liquid boiled, the splashing liquid would not reach the liquid phase sampling point through the conduit; the heating method was an electric heating rod;

[0036] (1) A test solution composed of 1,5-pentanediamine and water is prepared into 10 test samples at mass concentrations of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% respectively;

[0037] (2) The sample to be tested with a mass concentration of 0% obtained in step (1) is added to the equilibrium kettle, the pressure controller is turned on to set the measured pressure, and the voltage of the electric heating rod is slowly increased until the kettle liquid in the equilibrium kettle begins to boil. After stabilization, wait for 30 minutes to start observing the equilibrium temperature. After the equilibrium temperature is stable for 30 minutes, a liquid sample is obtained from the liquid sampling port, and a gas sample is obtained from the gas sampling port. After sampling, the power is turned off, the kettle liquid is poured out, and the equilibrium kettle is dried at 60°C. Then, samples to be tested with mass concentrations of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% are added respectively and the same operation is performed;

[0038] The measured pressures are 10 kPa, 40 kPa, 70 kPa, and 101.3 kPa;

[0039] The heating stabilization means that the voltage of the electric heating rod is increased again, and the equilibrium temperature of the kettle top does not increase within 10 minutes;

[0040] (3) The liquid sample and the gas sample obtained in step (2) are analyzed for their compositions by gas chromatography external standard method, and a comparison table of mass ratio, equilibrium temperature, and sample composition is listed. The vapor pressure is found according to the equilibrium temperature, and the activity coefficient is calculated based on Raoult's law. The theoretical value of the sample is calculated by Wilson's equation, and the binary gas-liquid equilibrium curve of 1,5-pentanediamine and water is obtained by aspen fitting, as shown in FIG. Figure 2 shown.

[0041] Example 2

[0042] The "1,5-pentanediamine" in Example 1 is replaced by "1,6-hexanediamine", and the other steps are the same as Example 1.

[0043] As can be seen from Example 1, the determination method of the present invention can be applied to binary gas-liquid equilibrium test of high-boiling-point substances and water, which supplements the basic theory of separation of two substances in high-boiling-point substances, provides an important theoretical basis for scale-up production, and reduces the trial-and-error cost of empirical scale-up.

[0044] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for determining binary gas-liquid equilibrium of explosively boiling substances composed of high boiling point substances and water, characterized in that: The steps include: (1) The test solution composed of the high boiling point substance and water is prepared into 10 test samples at mass concentrations of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% respectively; (2) placing the 10 samples obtained in step (1) in a gas-liquid equilibrium kettle for measurement to obtain the equilibrium temperature, and after the measurement, taking liquid phase samples and gas phase samples to obtain liquid phase samples and gas phase samples; (3) analyzing the composition of the liquid sample and the gas sample obtained in step (2) by using a gas chromatography external standard method, listing a comparison table of mass ratio, equilibrium temperature, and sample composition, finding the vapor pressure according to the equilibrium temperature, calculating the activity coefficient based on Raoult's law, calculating the theoretical value of the sample by using the Wilson equation, and obtaining a binary gas-liquid equilibrium curve by using Aspen fitting; The gas-liquid balance kettle comprises a heating sleeve, kettle liquid, an air guide tube, a riot ball, a thermometer sleeve, a condenser, a liquid phase sampling port, a vapor phase liquid sampling port and a sealing gasket; the sealing gasket comprises a through hole, and the diameter of the through hole is ≤0.5mm.

2. The method for determining the binary gas-liquid equilibrium of explosively boiling substances composed of high boiling point substances and water according to claim 1, characterized in that: The high boiling point substance is 1,5-pentanediamine or 1,6-hexanediamine.

3. The method for determining the binary gas-liquid equilibrium of an explosively boiling substance composed of a high boiling point substance and water according to claim 1 or 2, characterized in that: In the step (2), the pressure measured is independently 10 to 101.3 kPa.

4. The method for determining binary gas-liquid equilibrium of explosively boiling substances composed of high boiling point substances and water according to claim 3, characterized in that: In the step (2), the specific steps of the determination are independent: placing the 10 samples to be tested obtained in the step (1) in a gas-liquid equilibrium kettle respectively, setting the pressure of the measurement, and increasing the temperature of the samples to be tested until the samples to be tested boil; recording the temperature after heating stabilizes, which is the equilibrium temperature; and then performing liquid phase sampling and gas phase sampling after 20 to 40 minutes.

5. The method for determining binary gas-liquid equilibrium of explosively boiling substances composed of high boiling point substances and water according to claim 4, characterized in that: In the step (2), before each sample is measured, the gas-liquid equilibrium kettle is dried; the drying temperature is independently 40 to 80°C.

6. The method for determining binary gas-liquid equilibrium of explosively boiling substances composed of high boiling point substances and water according to claim 4 or 5, characterized in that: In the step (2), the heating is stable when the pressure to be measured is increased again and the temperature of the gas-liquid equilibrium kettle does not change within 8 to 12 minutes.

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