Vapor phase single cycle equilibrium still

Abstract

The present application relates to a kind of vapor phase single cycle balance kettle, including boiling kettle, riser, condenser, vapor phase condensate collection container one and vapor phase condensate collection container two in turn, vapor phase condensate collection container one is located above vapor phase condensate collection container two;Wherein, the bottom of vapor phase condensate collection container one is connected with the top of vapor phase condensate collection container two by series pipe;The bottom of vapor phase condensate collection container one and vapor phase condensate collection container two is respectively communicated with vapor phase sampling pipe;The upper end of vapor phase condensate collection container one, lower end and the lower end of vapor phase condensate collection container two are respectively connected with boiling kettle by condensate passage;Series pipe, vapor phase sampling pipe and from top to bottom second and third condensate passage are respectively installed with valve.The present application can continuously determine phase equilibrium data, and it is suitable for determining ternary or more phase equilibrium data under constant temperature condition.

Description

Technical Field

[0001] This invention relates to the field of chemical data measuring devices, specifically to a vapor phase single-circulation equilibrium vessel. Background Technology

[0002] A single-cycle vapor-liquid equilibrium vessel is an experimental apparatus used in chemical thermodynamics experiments to determine vapor-liquid phase equilibrium. Vapor-liquid equilibrium data plays a crucial supporting role in the development of new products and processes, energy reduction, and waste treatment in the chemical industry. With the continuous development of chemical production, existing vapor-liquid phase equilibrium data are far from meeting the needs. The phase equilibrium data for many systems are difficult to obtain directly from theoretical calculations and must be determined experimentally.

[0003] Existing vapor-liquid equilibrium reactors require repeated batching and feeding after each phase equilibrium measurement, making continuous phase equilibrium data measurement impossible, especially for ternary or more phase equilibrium data under isothermal conditions. Pre-batching is difficult to adjust to the predetermined temperature, and the batching trial work is very time-consuming. Furthermore, only one type of vapor phase sample is obtained from condensation, making segmented sampling impossible. When sampling the liquid phase in the equilibrium reactor, secondary evaporation due to high temperatures increases systematic errors in the experiment. In addition, traditional equilibrium reactors are prone to bumping during boiling. Although bubbling equilibrium reactors are reported in the literature, these require the introduction of an inert gas.

[0004] Therefore, how to provide an improved vapor phase single-circulation equilibrium vessel that can overcome the above problems is a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a vapor phase single-circulation equilibrium vessel that can continuously measure phase equilibrium data and is suitable for measuring phase equilibrium data of ternary or more components under isothermal conditions.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is: a vapor-phase single-circulation equilibrium vessel, comprising a boiling vessel, a riser, a condenser, a vapor-phase condensate collection container one, and a vapor-phase condensate collection container two connected in sequence, wherein the vapor-phase condensate collection container one is located above the vapor-phase condensate collection container two; wherein,

[0007] The bottom of the vapor phase condensate collection container one is connected to the top of the vapor phase condensate collection container two via a series pipe; the bottoms of the vapor phase condensate collection container one and the vapor phase condensate collection container two are respectively connected to vapor phase sampling pipes; the upper and lower ends of the vapor phase condensate collection container one and the lower end of the vapor phase condensate collection container two are respectively connected to the boiling kettle via condensate channels; valves are respectively installed on the series pipe, the vapor phase sampling pipe, and the second and third condensate channels from top to bottom.

[0008] As can be seen from the above technical solution, this invention features three condensate channels, two vapor phase condensate collection containers, and two vapor phase sampling tubes. This allows the operator to take samples sequentially and separately from the two vapor phase sampling tubes each time a sample is added. The liquid in the two vapor phase condensate collection containers can be returned to the boiling kettle sequentially and separately, or a portion of the material can be selectively removed. This enables continuous measurement of multiple sets of phase equilibrium data, significantly reducing the inconvenience of traditional equilibrium kettles requiring re-feeding after system cooling. More importantly, the unique structure of this invention facilitates temperature control of ternary or more elemental systems. In traditional equilibrium kettles, the temperature is determined by the total composition of the materials after they are added, and this temperature cannot be accurately predicted before the experiment begins. To measure the phase equilibrium data of a isothermal ternary or more elemental system at a predetermined temperature, repeated and lengthy feeding trials are necessary, and the equipment must repeatedly undergo heating and cooling processes. This invention, through the ingenious operation of two vapor phase condensate collection containers and several valves, allows for adjustment of the equilibrium temperature to a predetermined value without re-feeding. This function is impossible for existing traditional equilibrium kettles.

[0009] Furthermore, the valve installed on the series pipe is a three-way valve, which is configured to be adjustable in three states:

[0010] In the first case, the vapor phase condensate collection container one and the vapor phase condensate collection container two are connected;

[0011] The second type is where the vapor phase condensate collection container one and the vapor phase condensate collection container two are not connected, and the top of the vapor phase condensate collection container two is connected to the outside.

[0012] The third type is in which the vapor phase condensate collection container one and the vapor phase condensate collection container two are not connected, and the bottom of the vapor phase condensate collection container one is connected to the outside.

[0013] To further address the issue of boiling over in the boiling vessel, the top of the vapor phase condensate collection container is connected to the boiling vessel via a bubbling pipe. The bubbling pipe extends into the bottom of the boiling vessel, and a circulation pump is installed on the bubbling pipe. Under the action of the circulation pump, the gas at the top of the vapor phase condensate collection container enters the bottom of the boiling vessel through the bubbling pipe.

[0014] Furthermore, a valve is installed on the bubbling tube.

[0015] Furthermore, the vapor phase single-circulation balance vessel also includes an atmospheric connecting pipe connected to the upper end of the vapor phase condensate collection container two, and a valve is installed on the atmospheric connecting pipe.

[0016] To further facilitate the collection of liquid phase, the vapor phase single-circulation equilibrium vessel also includes a liquid phase collection container connected to the bottom of the boiling vessel via a liquid phase pipe. The bottom of the liquid phase collection container is connected to a liquid phase sampling pipe, and valves are installed on the liquid phase pipe and the liquid phase sampling pipe respectively.

[0017] Furthermore, to facilitate cooling of the liquid phase, the peripheral wall of the liquid phase collection container is equipped with a cooling jacket.

[0018] Furthermore, the boiling kettle is equipped with a temperature measuring device for measuring the internal temperature.

[0019] Furthermore, in order to reduce the impact of heat transfer from the periphery of the boiling vessel on the temperature inside the boiling vessel, the periphery of the boiling vessel is provided with a vacuum jacket.

[0020] Furthermore, the upper end of the boiling kettle is provided with a sample inlet.

[0021] By adopting the above technical solution, this invention designs two vapor phase condensate collection containers and three selectable condensate channels. The volume and concentration of the collected vapor phase condensate can be adjusted. Multiple sets of vapor-liquid phase equilibrium data can be measured each time a sample is added, making the entire vapor-liquid equilibrium measurement process more efficient and convenient. This invention can conveniently test ternary or multi-dimensional phase equilibrium data under isothermal conditions. A cooling jacket is added to the outside of the liquid phase collection container, allowing the condensate in the jacket to cool the liquid phase sample to be taken, overcoming the problem of secondary evaporation caused by the high temperature of the liquid phase sample during traditional equilibrium vessel sampling. This invention incorporates a circulation pump to circulate the gas above the vapor phase condensate collection container into the solution in the boiling vessel, avoiding the phenomenon of boiling over and surging within the boiling vessel. This invention has three selectable condensate channels, allowing for convenient and selective return of the distilled liquid to the boiling vessel for selective repeat distillation experiments, greatly saving operation time and avoiding the trouble and deviation caused by re-mixing. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the vapor phase single-circulation equilibrium vessel in an embodiment of the present invention;

[0023] Figure 2 This is a phase equilibrium data diagram of the ethanol-cyclohexane-water system in the embodiments of the present invention under normal pressure and constant temperature of 50°C.

[0024] Figure 3 This is a residual curve diagram of the isobutanol-water-benzene ternary system in the embodiments of the present invention. Detailed Implementation

[0025] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0026] like Figure 1 As shown, a vapor-phase single-circulation equilibrium vessel includes a boiling vessel 1, a riser 3, a condenser 7, a vapor-phase condensate collection container 9, and a vapor-phase condensate collection container 10 connected in sequence, wherein the vapor-phase condensate collection container 9 is located above the vapor-phase condensate collection container 10; wherein,

[0027] The bottom of the vapor phase condensate collection container 9 is connected to the top of the vapor phase condensate collection container 10 via a series pipe; the bottoms of the vapor phase condensate collection container 9 and the vapor phase condensate collection container 10 are respectively connected to vapor phase sampling pipes; the upper and lower ends of the vapor phase condensate collection container 9 and the lower end of the vapor phase condensate collection container 10 are respectively connected to the boiling kettle 1 via condensate channels; valves are installed on the series pipe, the vapor phase sampling pipe, and the second and third condensate channels from top to bottom.

[0028] like Figure 1 As shown, the valve installed on the series pipe is a three-way valve, which is configured to be adjustable in three states:

[0029] In the first case, the vapor phase condensate collection container 9 and the vapor phase condensate collection container 10 are connected;

[0030] The second type is in which the vapor phase condensate collection container 9 and the vapor phase condensate collection container 10 are not connected, and the top of the vapor phase condensate collection container 10 is connected to the outside.

[0031] The third type is in which the vapor phase condensate collection container 9 and the vapor phase condensate collection container 10 are not connected, and the bottom of the vapor phase condensate collection container 9 is connected to the outside.

[0032] In this embodiment, the first port of the three-way valve is connected to the bottom of the vapor phase condensate collection container 19, the second port is connected to the top of the vapor phase condensate collection container 20, and the third port is connected to the vapor phase sampling tube of the vapor phase condensate collection container 19. The three-way valve controls the series tube and the corresponding vapor phase sampling tube.

[0033] like Figure 1As shown, in order to solve the problem of boiling up in the boiling kettle 1, the top of the vapor phase condensate collection container 9 is connected to the boiling kettle 1 through a bubble tube 6. The bubble tube 6 extends into the bottom of the boiling kettle 1, and a circulation pump 8 is installed on the bubble tube 6. The gas at the top of the vapor phase condensate collection container 9 enters the bottom of the boiling kettle 1 through the bubble tube 6 under the action of the circulation pump 8.

[0034] like Figure 1 As shown, a valve is installed on the bubbling tube 6.

[0035] like Figure 1 As shown, the vapor phase single-circulation equilibrium vessel also includes an atmospheric connecting pipe connected to the upper end of the vapor phase condensate collection container 2 10, and a valve is installed on the atmospheric connecting pipe.

[0036] like Figure 1 As shown, in order to facilitate the collection of liquid phase, a liquid phase collection container 14 is also included, which is connected to the bottom of the boiling kettle 1 through a liquid phase pipe. The bottom of the liquid phase collection container 14 is connected to a liquid phase sampling pipe, and valves are respectively installed on the liquid phase pipe and the liquid phase sampling pipe.

[0037] like Figure 1 As shown, the peripheral wall of the liquid phase collection container 14 is provided with a cooling jacket 15.

[0038] like Figure 1 As shown, the boiling kettle 1 is equipped with a temperature measuring device 5 for measuring the internal temperature.

[0039] like Figure 1 As shown, in order to reduce the influence of heat transfer from the periphery of the boiling vessel 1 on the temperature inside the boiling vessel 1, the periphery of the boiling vessel 1 is provided with a vacuum jacket 2.

[0040] like Figure 1 As shown, the upper end of the boiling vessel 1 is provided with a sample inlet 4.

[0041] The advantages of the technical solutions involved in the above embodiments are analyzed below.

[0042] The three condensate channels are designated from top to bottom as Condensate Channel 1 (11), Condensate Channel 2 (12), and Condensate Channel 3 (13); the valve on the bubbling tube 6 is designated as Valve A; the valve on Condensate Channel 2 (12) is designated as Valve B; the three-way valve is designated as Valve C; the valve on the atmospheric connection pipe is designated as Valve D; the valve on Condensate Channel 3 (13) is designated as Valve E; the valve on the vapor phase sampling tube of the vapor phase condensate collection container 2 (10) is designated as Valve F; the valve on the liquid phase tube is designated as Valve G; and the valve on the liquid phase sampling tube is designated as Valve H; as detailed below. Figure 1 As shown.

[0043] like Figure 1As shown, the riser pipe 3 is arranged inside the boiling kettle 1, with an opening at the bottom. After the sample in the boiling kettle 1 is heated by the heater at the lower end, the generated vapor phase enters the condenser 7 through the riser pipe 3 for condensation. The condensed vapor phase flows into the vapor phase condensate collection container 9 and the vapor phase condensate collection container 10. By adjusting the opening and closing states of valves B and E, the condensate is allowed to flow back into the boiling kettle 1. When the temperature measured by the temperature measuring device 5 reaches a certain value and remains constant for a period of time, that is, when vapor-liquid equilibrium is reached, the vapor phase condensate is sampled through valve C or valve F, and the liquid phase is sampled through valve H.

[0044] One advantage of this single-circulation vapor-phase equilibrium vessel is that multiple sets of vapor-liquid phase equilibrium data can be measured each time a sample is added, making the entire vapor-liquid equilibrium determination process more efficient and convenient. When valve E is open, valve C connects vapor-phase condensate collection container 1 (9) and vapor-phase condensate collection container 2 (10). Vapor-phase condensate collection container 1 (9) has no liquid level, while the liquid level in vapor-phase condensate collection container 2 (10) is at its lowest. When valve E is closed and valve B is open, vapor-phase condensate collection container 2 (10) will be filled with vapor-phase condensate, and the liquid level in vapor-phase condensate collection container 9 will be at a lower position. When both valves E and B are closed, the liquid level in vapor-phase condensate collection container 9 will be at its highest position. At the beginning of the experiment, the total amount of material added to the boiling vessel 1 is a fixed value. After boiling and evaporation splits into vapor and liquid phases, the volume of vapor phase remaining in vapor-phase condensate collection containers 1 (9) and 2 (10) is directly related to the vapor phase composition and the liquid phase composition in the boiling vessel 1. The pattern should be as follows: when the collected vapor phase condensate volume is small, the concentration of heavy components is low, and the composition of the liquid phase in equilibrium is close to the feed composition. This is because the total mass of vapor phase evaporated is very small at this time. When the collected vapor phase condensate volume increases, the concentration of heavy components increases, and the composition gradually approaches the feed composition. On the other hand, the concentration of light components in the liquid phase in equilibrium decreases. By adjusting the opening and closing states of valves B, C, and E, the vapor phase volume in vapor phase condensate collection container 19 and vapor phase condensate collection container 20 can be varied at different locations. Therefore, by adding feed once, the light and heavy components can be redistributed, and multiple sets of equilibrium data points can be measured.

[0045] The second advantage of this vapor-phase single-circulation equilibrium vessel is its suitability for determining phase equilibrium data of ternary or more elemental systems under isothermal conditions. Because it has two vapor-phase condensate collection containers, the distilled components can be divided into two segments: the initial component is collected in vapor-phase condensate collection container 2 (10), and the intermediate component is collected in vapor-phase condensate collection container 1 (9). By adjusting the states of several valves, the retention or removal of the initial and intermediate components can be controlled, thus achieving temperature regulation. If existing equilibrium vessels are used to determine the phase equilibrium of ternary or more elemental systems at a predetermined temperature, repeated trial feeding is required, consuming a significant amount of time and making it difficult to control the temperature at the predetermined value. Using the novel equilibrium vessel described in this embodiment, the operations described below can be performed more conveniently to adjust the temperature to the predetermined value.

[0046] The following example illustrates the operation of the vapor-liquid equilibrium vessel in this embodiment, using the determination of the vapor-liquid phase equilibrium of the ethanol-cyclohexane-water system at a constant temperature of 50°C. The sample is added through inlet 4, condenser 7 is circulated with cooling water, and an external heater heats the bottom of the boiling vessel 1. Under normal operating conditions, valve B is closed, valve C is adjusted to connect vapor-phase condensate collection container 1 (9) and vapor-phase condensate collection container 2 (10), and valve E is opened, allowing the condensate in vapor-phase condensate collection container 2 (10) to flow into the boiling vessel 1. This continues until the temperature measured by the temperature measuring device 5 remains constant for more than 40 minutes, indicating vapor-liquid equilibrium. Then, valves F, G, and H are opened respectively. The vapor phase sample is taken through valve F, and the liquid phase sample is taken through valves G and H.

[0047] When the first scenario occurs, i.e., the equilibrium temperature is higher than the predetermined value, valve C is adjusted to isolate the vapor phase condensate collection container 9 from the vapor phase condensate collection container 10. Simultaneously, valve D connects the upper part of the vapor phase condensate collection container 10 to the atmosphere. Valve E is closed, and boiling continues, allowing some components in the boiling kettle 1 to vaporize and condense into the vapor phase condensate collection container 9. At this point, compared to the components that have already evaporated and are stored in the vapor phase condensate collection container 10, the components in the vapor phase condensate collection container 9 are relatively heavier and have a higher boiling point. After an appropriate time, valve E is opened, allowing the relatively lighter components in the vapor phase condensate collection container 10 to flow back into the boiling kettle 1. Because some relatively heavier components have already evaporated in the boiling kettle 1, and some relatively lighter components are flowing back, the boiling temperature will decrease. At this point, adjust valve C to allow the liquid in vapor phase condensate collection container 9 to flow into vapor phase condensate collection container 2 (10). Simultaneously close valve E. After the relatively heavier components flow from vapor phase condensate collection container 9 to vapor phase condensate collection container 2 (10), open valve B to allow the vapor phase condensate collected in vapor phase condensate collection container 9 to flow into the boiling kettle. Adjust valve C to isolate vapor phase condensate collection container 9 from vapor phase condensate collection container 2 (10). After the temperature stabilizes, the condensate in vapor phase condensate collection container 9 can be sampled. During sampling, adjust valve C to maintain the isolation between vapor phase condensate collection container 9 and vapor phase condensate collection container 2 (10), while ensuring that vapor phase condensate collection container 9 is connected to its vapor phase sampling tube.

[0048] When the second scenario occurs, i.e., the equilibrium temperature is lower than the predetermined value, keep the vapor phase condensate collection container 19 connected to the vapor phase condensate collection container 20, close valve E, and continue boiling. This allows some components in the boiling kettle 1 to vaporize and condense, entering and remaining in the vapor phase condensate collection container 20. After an appropriate time, adjust the three-way valve C to disconnect the vapor phase condensate collection container 19 from the vapor phase condensate collection container 20, and close valve B, allowing the vaporized components to enter the vapor phase condensate collection container 19. At this point, compared to the components that have already been boiled, evaporated, and stored in the vapor phase condensate collection container 20, the components in the vapor phase condensate collection container 19 are relatively heavier and have a higher boiling point. After an appropriate time, open valve B, allowing the relatively heavier components in the vapor phase condensate collection container 19 to flow into the boiling kettle 1 through the condensate channel 212. Alternatively, keep valve B closed until there is enough condensate in the vapor phase condensate collection container 19, which will then flow into the boiling kettle 1 through the condensate channel 11. Because some relatively lighter components are missing from the boiling kettle 1, and some relatively heavier components flow in, the boiling temperature will rise. After the temperature stabilizes, the condensate in the vapor phase condensate collection container 9 can be sampled. During sampling, valve C is adjusted to keep the vapor phase condensate collection container 9 isolated from the vapor phase condensate collection container 10, and to connect the vapor phase condensate collection container 9 to the vapor phase sampling tube.

[0049] Through the above procedures, the phase equilibrium data of the ethanol-cyclohexane-water system under normal pressure and isothermal conditions of 50℃ were obtained through sampling and analysis. The data are shown below. Figure 2 .

[0050] The third advantage of this vapor phase single-circulation equilibrium vessel is that the liquid phase collection container 14 is equipped with a cooling jacket 15, which allows for the circulation of cold water to cool the liquid phase sample entering the liquid phase collection container 14, i.e., cooling before releasing the sample out of the system. This overcomes the problem of secondary evaporation caused by the high temperature of the liquid phase sample during traditional equilibrium vessel liquid phase sampling, and reduces systematic errors in the experiment.

[0051] Furthermore, by using the three condensate channels of the vapor phase single-circulation equilibrium vessel in this embodiment, the distillate liquid can be conveniently and selectively returned to the boiling vessel 1 for selective repeat distillation experiments, which can greatly save operation time and avoid the trouble and deviation caused by re-mixing, thus accomplishing functions that are difficult to achieve with traditional distillation equipment.

[0052] The residual curve of the isobutanol-water-benzene ternary system was determined using the vapor-phase single-circulation equilibrium vessel in this embodiment. A mixture of isobutanol, water, and benzene in a certain proportion was added to the boiling vessel 1, with a molar ratio of isobutanol:water:benzene = 4:1:5. Water was circulated through the condenser 7, and all valves were closed. The temperature was recorded when the mixture in the boiling vessel 1 began to boil. Simultaneously, the liquid in the boiling vessel 1 was taken for composition analysis by TCE chromatography to obtain the residual curve of the isobutanol-water-benzene ternary system. The experimental data are shown below. Figure 3 .

[0053] The fourth advantage of this balance vessel is that it is equipped with a circulation pump 8, which circulates the gas above the vapor phase condensate collection container 9 to the bottom of the boiling vessel 1, thus avoiding the boiling and surging phenomenon commonly seen in traditional balance vessels.

[0054] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A vapor-phase single-circulation equilibrium vessel, characterized in that, The system includes a boiling kettle (1), a riser (3), a condenser (7), a vapor phase condensate collection container one (9), and a vapor phase condensate collection container two (10), which are connected in sequence. The vapor phase condensate collection container one (9) is located above the vapor phase condensate collection container two (10). The bottom of the vapor phase condensate collection container one (9) is connected to the top of the vapor phase condensate collection container two (10) via a series pipe; The bottoms of the vapor phase condensate collection container one (9) and the vapor phase condensate collection container two (10) are respectively connected to vapor phase sampling tubes; The upper and lower ends of the vapor phase condensate collection container one (9) and the lower end of the vapor phase condensate collection container two (10) are respectively connected to the boiling kettle (1) through condensate channels; Valves are installed on the series pipe, the vapor phase sampling pipe, and the second and third condensate channels from top to bottom, respectively; The valve installed on the series pipe is a three-way valve, which is configured to be adjustable in three states: In the first case, the vapor phase condensate collection container one (9) and the vapor phase condensate collection container two (10) are connected; The second type is where the vapor phase condensate collection container one (9) and the vapor phase condensate collection container two (10) are not connected, and the top of the vapor phase condensate collection container two (10) is connected to the outside. The third type is where the vapor phase condensate collection container one (9) and the vapor phase condensate collection container two (10) are not connected, and the bottom of the vapor phase condensate collection container one (9) is connected to the outside.

2. The vapor-phase single-circulation equilibrium vessel according to claim 1, characterized in that, The top of the vapor phase condensate collection container (9) is connected to the boiling kettle (1) through a bubbling pipe (6). The bubbling pipe (6) extends into the bottom of the boiling kettle (1). A circulation pump (8) is installed on the bubbling pipe (6). The gas at the top of the vapor phase condensate collection container (9) enters the bottom of the boiling kettle (1) through the bubbling pipe (6) under the action of the circulation pump (8).

3. The vapor-phase single-circulation equilibrium vessel according to claim 2, characterized in that, A valve is installed on the bubbling tube (6).

4. The vapor-phase single-circulation equilibrium vessel according to claim 1, characterized in that, It also includes an atmospheric communication pipe connected to the upper end of the vapor phase condensate collection container (10), and a valve is installed on the atmospheric communication pipe.

5. The vapor-phase single-circulation equilibrium vessel according to claim 1, characterized in that, It also includes a liquid phase collection container (14) connected to the bottom of the boiling kettle (1) via a liquid phase pipe, the bottom of the liquid phase collection container (14) being connected to a liquid phase sampling pipe, and valves being installed on the liquid phase pipe and the liquid phase sampling pipe respectively.

6. The vapor-phase single-circulation equilibrium vessel according to claim 5, characterized in that, The peripheral wall of the liquid phase collection container (14) is provided with a cooling jacket (15).

7. The vapor-phase single-circulation equilibrium vessel according to claim 1, characterized in that, The boiling kettle (1) is equipped with a temperature measuring device (5) for measuring the temperature inside.

8. The vapor-phase single-circulation equilibrium vessel according to claim 1, characterized in that, The boiling kettle (1) is provided with a vacuum jacket (2) on its peripheral wall.

9. The vapor-phase single-circulation equilibrium vessel according to claim 1, characterized in that, The upper end of the boiling kettle (1) is provided with a sample inlet (4).

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