A method and apparatus for sampling to stabilize light hydrocarbon saturated vapor pressure determination

Abstract

The application provides a sampling method and device for stably determining saturated vapor pressure of light hydrocarbon, which comprises a sampling bottle, a measuring bottle, a heat preservation balance base and a liquid chamber and a gas chamber; the volume of the light hydrocarbon saturated vapor is less than the total volume of the sampling bottle in the transportation process, so that the problem of explosion of the light hydrocarbon saturated vapor due to volume expansion in the transportation process is avoided; secondly, the transportation is in a constant temperature state, so that the sample is not excessively heated in the transportation process and the components of the sample are relatively stable after the gas-liquid balance in the steel bottle. In addition, the sampling bottle and the liquid chamber are subjected to refrigeration treatment; the liquid chamber is refrigerated to ℃ together with the heat preservation fixed base in the refrigerator, and the components do not change greatly after being taken out of the refrigerator and being kept at a relatively constant temperature for a set time, so that the accuracy of measurement is ensured; through experiments on 20 groups of samples, the problem of poor measurement repeatability is solved, the analysis result repeatability completely meets the standard requirements, and the analysis result is 100% accurate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of light hydrocarbon detection, in particular to a sampling method and device for determining the saturated vapor pressure of light hydrocarbon. BACKGROUND

[0002] The saturated vapor pressure is an important quality index of stable light hydrocarbon, and accurate analysis of the saturated vapor pressure of stable light hydrocarbon is related to the safety of production, storage and transportation of stable light hydrocarbon. Since stable light hydrocarbon is extremely easy to evaporate at room temperature and normal pressure, the determination of the saturated vapor pressure is extremely sensitive to the evaporation loss and component change of the sample, so necessary measures must be taken and careful operation must be performed in the analysis operation. Since the determination of the vapor pressure should use the sample extracted from the sample for the first time, the sample left in the container cannot be used for the second vapor pressure experiment, and if the second experiment is needed, the sample must be taken again, and the sampling site is generally far away, and the cost of human and material resources is high due to repeated sampling. The evaporation loss and poor repeatability of the analysis results in the sampling and transfer process of the saturated vapor pressure of stable light hydrocarbon have been a difficult problem for analysts. SUMMARY

[0003] In view of the problems in the prior art, the present application provides an auxiliary combined device and method for determining the saturated vapor pressure of stable light hydrocarbon, which completely solves the problem of poor repeatability of the saturated vapor pressure analysis of stable light hydrocarbon and the problem of inaccurate analysis results.

[0004] The present application is achieved by the following technical solutions:

[0005] A sampling method for determining the saturated vapor pressure of stable light hydrocarbon, comprising the following steps:

[0006] Step 1, filling a sampling bottle with a set volume of light hydrocarbon saturated vapor, and the set volume is less than the volume of the sampling bottle;

[0007] Step 2, transporting the sampling bottle filled with light hydrocarbon saturated vapor to a predetermined position under constant temperature conditions;

[0008] Step 3, performing low-temperature treatment on the sampling bottle of step 2 until a preset temperature is reached;

[0009] Step 4, refrigerating the liquid chamber to a predetermined temperature, and performing water area treatment on the gas chamber to a set temperature;

[0010] Step 5, connecting the sampling bottle obtained in step 3 with the liquid chamber obtained in step 4 within a set time, and injecting the light hydrocarbon saturated vapor into the liquid chamber;

[0011] Step 6, connecting the liquid chamber with the gas chamber obtained in step 4, so that the light hydrocarbon saturated vapor in the liquid chamber enters the gas chamber, and then performing pressure measurement.

[0012] Preferably, the set volume in step 1 is less than or equal to 80% of the volume of the sampling bottle.

[0013] Preferably, the sampling bottle is transported by using a constant temperature device in step 2, and the constant temperature is 37-38℃.

[0014] Preferably, the refrigeration temperature in step 3 is 0-1℃, and the water bath temperature is 38±1℃.

[0015] Preferably, the liquid chamber is installed in the heat preservation balance base for refrigeration treatment in step 3.

[0016] Preferably, the set time in step 4 is less than 10 seconds.

[0017] A device for stabilizing the sampling method of determining the saturated vapor pressure of light hydrocarbon, comprising a sampling bottle, a measuring flask, a heat preservation balance base and a liquid chamber and a gas chamber.

[0018] The sampling bottle is provided with an air inlet and an air outlet, the air inlet of the sampling bottle is used for being connected with a gas source, the air outlet of the sampling bottle is used for being connected with the measuring flask or the liquid chamber, the liquid chamber is arranged in the heat preservation balance base, and the liquid chamber and the gas chamber are communicated.

[0019] Preferably, the sampling bottle is connected with the measuring flask or the liquid chamber through a pipeline, the pipeline is an anti-static pressure-resistant pipeline, and quick clamping joints are arranged at two ends of the pipeline.

[0020] Preferably, at least one cavity for installing the liquid chamber is arranged in the heat preservation balance base, a heat preservation layer is arranged around the cavity, and a surface of the heat preservation balance base is provided with a mark for positioning the clamping position of the quick clamping structure.

[0021] Preferably, the surface of the measuring flask is provided with a scale.

[0022] Compared with the prior art, the present application has the following beneficial technical effects:

[0023] The application provides a sampling method for stabilizing light hydrocarbon saturated vapor pressure determination, which makes the volume of light hydrocarbon saturated vapor less than the total volume of the sampling bottle during transportation, so that the problem of explosion due to volume increase during light hydrocarbon saturated vapor transportation is avoided, and the safety of transportation is improved. Secondly, the transportation under constant temperature state ensures that the sample is not excessively heated during transportation, and also ensures that the components are relatively stable after the sample is in gas-liquid balance in the steel bottle. In addition, the sampling bottle and the liquid chamber are subjected to refrigeration treatment, since the liquid chamber is refrigerated to ℃ together with the heat preservation fixed base in the refrigerator, and after being taken out of the refrigerator, the components will not change greatly within a set time under relatively constant temperature, so that the accuracy of measurement is ensured. Through experiments on 20 groups of samples, the problem of poor measurement repeatability is completely solved, the analysis result repeatability completely meets the standard requirements, the analysis result accuracy is ensured to be 100%, and the analysis technical problem is completely solved. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a schematic view of connection of the sampling bottle and the gas source of the application.

[0025] Figure 2 It is a schematic view of connection of the sampling bottle and the measuring bottle of the application.

[0026] Figure 3 It is a schematic view of connection of the sampling bottle and the liquid chamber of the application.

[0027] Figure 4 It is a plan view of the heat preservation balance base of the application.

[0028] In the figure: 1, sampling bottle; 2, measuring bottle; 3, gas inlet end; 4, gas outlet end; 5, valve; 6, gas source; 7, liquid chamber; 8, heat preservation balance base; 9, mark. DETAILED DESCRIPTION

[0029] The application will be further described in detail below in combination with the drawings, which is an explanation but not a limitation of the application.

[0030] A sampling method for stabilizing light hydrocarbon saturated vapor pressure determination, comprising the following steps:

[0031] Step 1, collecting light hydrocarbon saturated vapor by using a sampling bottle, and making the volume of light hydrocarbon saturated vapor less than 80% of the volume of the sampling bottle;

[0032] The light hydrocarbon saturated vapor is injected from the inlet of the sampling bottle and filled, and then 20% of the volume is discharged, so that 20% of space is reserved in the sampling bottle, so that the problem of explosion due to volume increase during light hydrocarbon saturated vapor transportation is avoided, and the safety of transportation is improved.

[0033] Step 2, transporting the sampling bottle filled with light hydrocarbon saturated vapor to the laboratory under constant temperature state.

[0034] The sampling vials filled with saturated vapor of light hydrocarbons were transported in a constant temperature chamber at 37-38°C. This chamber ensured that the samples were not overheated during transport and that the components remained relatively stable after the samples reached gas-liquid equilibrium within the cylinder.

[0035] Step 3: Perform low-temperature treatment on the sampling bottle from Step 2 until the preset temperature is reached;

[0036] After the sampling bottles are transported to the laboratory, they are transferred to a cold storage room for storage, so that the temperature of the light hydrocarbon saturated vapor is reduced to a preset temperature of 0-1℃. In this way, when the bottles are taken out for use, the light hydrocarbon saturated vapor will be at a relatively constant temperature for a short period of time, and the composition will not change significantly.

[0037] Step 4: Refrigerate the liquid chamber to the predetermined temperature, and at the same time treat the gas chamber with water to the set temperature;

[0038] Specifically, the liquid chamber is placed in an insulated base, and the insulated base and the liquid chamber are refrigerated together. The predetermined temperature for refrigerating the liquid chamber is 0-1℃, and the set temperature for water bath treatment of the gas chamber is 38±1℃.

[0039] Since the liquid chamber is refrigerated to ℃ along with the insulated base, it remains at a relatively constant temperature for a short period after being taken out of the refrigerator, and the composition will not change significantly.

[0040] Step 5: Connect the sampling bottle obtained in Step 3 to the liquid chamber obtained in Step 4 within the set time, and inject the light hydrocarbon saturated vapor into the liquid chamber.

[0041] The set time is less than 10 seconds. In order to shorten the connection time between the sampling bottle and the liquid chamber, the sampling bottle and the liquid chamber are connected by a quick-lock connector. A positioning indicator is set on the surface of the heat-insulating balance base. The positioning indicator is for the position of the quick-lock connector. The visual markings on the base can help operators quickly find the liquid chamber position, which can greatly shorten the connection time between the gas chamber and the liquid chamber.

[0042] Secondly, thanks to the heat-insulating and balancing base, the liquid surface will remain flat after the sample is injected to prevent spillage. This is because if even a drop spills, the entire operation will be wasted, thus improving operational stability.

[0043] Step 6: Connect the liquid chamber to the gas chamber obtained in Step 4, so that the saturated vapor of light hydrocarbons in the liquid chamber enters the gas chamber and the pressure is measured.

[0044] Using this method, experiments were conducted on 20 groups of samples, which solved the problem of poor repeatability. The repeatability of the analytical results fully met the standard requirements, ensuring 100% accuracy of the analytical results and completely solving the technical difficulties of laboratory analysis.

[0045] The application also provides a sampling device for stabilizing light hydrocarbon saturated vapor pressure determination, which comprises a sampling bottle 1, a measuring bottle 2, a heat preservation balance base 8 and a liquid chamber 7 and a gas chamber.

[0046] The sampling bottle 1 is provided with an air inlet 3 and an air outlet 4, the air inlet 3 of the sampling bottle 1 is used for being connected with an air source 6, the air outlet 4 of the sampling bottle 1 is used for being connected with the measuring bottle 2 or the liquid chamber 7, the liquid chamber is arranged in the heat preservation balance base 8, and the liquid chamber and the gas chamber are communicated.

[0047] The heat preservation balance base 8 is provided with at least one cavity for matching the liquid chamber, and the cavity is provided with a heat preservation layer around.

[0048] The sampling bottle is connected with the measuring bottle or the liquid chamber through a pipeline, the pipeline is an anti-static pressure-resistant pipeline, and quick coupling joints are arranged at two ends of the pipeline.

[0049] The heat preservation balance base 8 is provided with at least one cavity for matching the liquid chamber, and the cavity is provided with a heat preservation layer around.

[0050] The surface of the heat preservation balance base 8 is provided with an identification mark 9, which is used for positioning the buckle position of the quick coupling structure.

[0051] The measuring bottle and the sampling bottle are made of stainless steel, in the sampling process, the air inlet of the sampling bottle is connected with the air source through a valve 5, and the surface of the measuring bottle is provided with a scale.

[0052] In use, the sampling bottle is connected with the air source through the valve, the valve is opened to fill the sampling bottle with light hydrocarbon saturated vapor until the sampling bottle is filled, then the sampling bottle is connected with the measuring bottle, 20% of the volume of the light hydrocarbon saturated vapor is discharged into the measuring bottle, the scale arranged on the measuring bottle can accurately discharge 20% of the volume, which not only ensures that there is space for the gasification of the liquid in the transportation process to ensure the transportation safety, but also ensures that the components of the sample are relatively stable after the gas-liquid balance in the cylinder.

[0053] Then, the sampling bottle is placed in a thermostat, which can ensure that the sample is not excessively heated during transportation. The sealed transportation of the thermostat reduces the evaporation loss, when the sampling bottle arrives at the test, the sampling bottle, the liquid chamber and the heat preservation balance base are refrigerated to ℃ in a refrigerator, and the liquid chamber is subjected to water bath treatment.

[0054] Finally, the refrigeration-treated sample bottle, liquid chamber and heat preservation balance base are taken out from the refrigerator, and the components will not change greatly in a short time after being taken out. The visual identification on the heat preservation balance base can help the operator quickly find the liquid chamber socket, which can greatly shorten the connection time of the gas chamber and the liquid chamber. At the same time, due to the balance base, the liquid surface will remain flat after the sample is injected into the liquid to prevent spilling. Once a drop is spilled, the entire operation will be in vain. Because the repeatability of stable light hydrocarbon saturated vapor pressure analysis is poor, we innovated this auxiliary combination device. After 20 groups of samples were tested, the repeatability problem was completely solved, the analysis result repeatability completely met the standard requirements, and the analysis result accuracy was ensured to be 100%, which completely solved the analysis technology problem.

[0055] The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the claims of the present application.

Claims

1. A sampling method for determining the saturated vapor pressure of stable light hydrocarbons, characterized in that, Includes the following steps: Step 1: Fill the sampling bottle with a set volume of light hydrocarbon saturated vapor, the set volume being smaller than the volume of the sampling bottle; The set volume is less than or equal to 80% of the sampling bottle volume; Step 2: Transport the sampling bottle filled with saturated vapor of light hydrocarbons to the predetermined location under constant temperature conditions; Step 3: Perform low-temperature treatment on the sampling bottle from Step 2 until the preset temperature is reached; Step 4: Refrigerate the liquid chamber to the predetermined temperature, and at the same time, treat the gas chamber with a water bath to the set temperature; The refrigeration temperature is 0-1℃, and the water bath temperature is 38±1℃. Step 5: Connect the sampling bottle obtained in Step 3 to the liquid chamber obtained in Step 4 within a set time, and inject the light hydrocarbon saturated vapor into the liquid chamber. Step 6: Connect the liquid chamber to the gas chamber obtained in Step 4, so that the saturated vapor of light hydrocarbons in the liquid chamber enters the gas chamber and the pressure is measured.

2. The sampling method for determining the saturated vapor pressure of stable light hydrocarbons according to claim 1, characterized in that, In step 2, a constant temperature device is used to transport the sampling bottles, and the constant temperature is 37-38℃.

3. The sampling method for determining the saturated vapor pressure of stable light hydrocarbons according to claim 1, characterized in that, In step 3, the liquid chamber is fitted into the insulated balance base (8) for refrigeration.

4. The sampling method for determining the saturated vapor pressure of stable light hydrocarbons according to claim 1, characterized in that, The time set in step 4 is less than 10 seconds.

5. An apparatus for sampling a method for determining the saturated vapor pressure of stable light hydrocarbons as described in any one of claims 1-4, characterized in that, It includes a sampling bottle (1), a volumetric flask (2), a thermal balance base (8), a liquid chamber (7), and a gas chamber; The sampling bottle (1) is provided with an air inlet (3) and an air outlet (4). The air inlet (3) of the sampling bottle (1) is used to connect to the gas source (6), and the air outlet (4) of the sampling bottle (1) is used to connect to the volumetric bottle (2) or the liquid chamber (7). The liquid chamber is set in the heat-insulating balance base (8), and the liquid chamber and the gas chamber are connected.

6. The apparatus for sampling in a method for determining the saturated vapor pressure of stable light hydrocarbons according to claim 5, characterized in that, The sampling bottle is connected to a volumetric flask or liquid chamber via a pipe. The pipe is an anti-static and pressure-resistant pipe, and quick-clamp connectors are provided at both ends of the pipe.

7. The apparatus for sampling in the determination of the saturated vapor pressure of stable light hydrocarbons according to claim 5, characterized in that, The thermal insulation balance base (8) is provided with at least one cavity for fitting the liquid chamber. The cavity is surrounded by a thermal insulation layer. The surface of the thermal insulation balance base (8) is provided with a mark (9) for positioning the buckle position of the quick-release structure.

8. The apparatus for sampling in a method for determining the saturated vapor pressure of stable light hydrocarbons according to claim 5, characterized in that, The surface of the measuring bottle is provided with graduations.

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