A trace gas metering device in a gold tube thermal simulation experiment

Abstract

A kind of trace gas metering device in gold tube thermal simulation experiment.The existing thermal simulation experiment is mainly solved when trace gas metering equipment is high in cost, operation is complex and unsafe, limited condition is more, cannot directly obtain the problem of gas volume.It is characterized in that: the gas taking system (1) and vacuum system (2) between, gas taking system (1) and auxiliary gas system (3) are connected through valve system (5) respectively;It also includes metering system (4), the metering system (4) is used to measure the gas volume discharged by gas taking system (1), and the gas taking system (1) is connected with metering system (4) through valve system (5).The trace gas metering device in gold tube thermal simulation experiment is safe in operation, gas volume can be directly obtained, and the device is simple and low in cost.

Description

Technical Field

[0001] This invention relates to the field of oil and gas geochemical experiments, specifically a trace gas metering device for a gold tube thermal simulation experiment. Background Technology

[0002] The gold tube thermal simulation experiment is an important means of evaluating the hydrocarbon generation potential and resources of source rocks. The most important part of the experiment is the collection and measurement of products. Only when the oil and gas products are collected completely and measured accurately can the amount of oil and gas resources be accurately estimated.

[0003] Currently, the method used abroad for measuring trace gases in thermal simulation experiments involves puncturing a gold tube inside a vacuum glass tube with a needle valve. After the gas is released, it is transferred from the glass tube to the gas chamber by the repeated up-and-down movement of the mercury level in a mercury pump. The amount of gas is then determined based on the height of the mercury level. Some domestic scholars have proposed a "device and method for collecting and quantifying gases and light hydrocarbon components in a gold sample tube" (patent number CN 101021513A). This method involves puncturing the gold tube with a needle valve, allowing the gas to enter the sampling loop of a gas chromatograph. Because the volume ratio of the sampling loop to the gas chamber is fixed, the gas pressure can be calculated more accurately, thus determining the amount of gas.

[0004] The above two methods have the following problems: (1) For foreign equipment, a large amount of mercury is required. If it is leaked, it will cause an accident and damage the environment. Moreover, the method requires a high vacuum environment, the equipment is complex, and the maintenance cost is high; (2) Both methods determine the amount of gas by gas pressure and do not directly give the gas volume; (3) It is expensive to equip the gas chromatograph with a separate quantitative sampling loop and it is not suitable for assembling old experimental equipment. Summary of the Invention

[0005] To overcome the problems of high cost, complex and unsafe operation, numerous limiting conditions, and inability to directly determine gas volume in existing micro-gas metering devices for thermal simulation experiments, this invention provides a micro-gas metering device for gold tube thermal simulation experiments. This micro-gas metering device for gold tube thermal simulation experiments is safe to operate, can directly determine gas volume, and is simple and inexpensive.

[0006] The technical solution of the present invention is: a trace gas metering device for a gold tube thermal simulation experiment, comprising a gas sampling system, a vacuum system, an auxiliary gas system, a metering system, and a valve system. The gas sampling system and the vacuum system, and the gas sampling system and the auxiliary gas system are respectively connected through the valve system. The metering system is used to measure the volume of gas discharged by the gas sampling system, and the gas sampling system and the metering system are connected through the valve system.

[0007] The metering system includes a standard tube and a digital caliper. One end of the standard tube is connected to a valve system. A track is provided between the standard tube and the digital caliper, and the standard tube, track, and digital caliper are parallel to each other. A photoelectric positioner is connected to the track, and the photoelectric positioner is connected to the pointer of the digital caliper.

[0008] The standard tube, track, and digital caliper are placed horizontally.

[0009] The standard tube contains a liquid column, and the photoelectric positioner is aligned with the end face of the liquid column and moves with the movement of the liquid column.

[0010] The outer wall of the standard tube is translucent.

[0011] The gas extraction system includes a cavity, a gold tube fixed inside the cavity, a needle valve connected to the outside of the cavity, with the end of the needle valve located on the upper part of the gold tube, and the cavity connected to a valve system via pipelines.

[0012] A limiter is fixed inside the cavity, the gold tube is located inside the limiter, and the upper part of the limiter is hollowed out.

[0013] The auxiliary gas in the auxiliary gas system is an inert gas.

[0014] The valve system includes a first valve, a second valve, a third valve, and a fourth valve, which are connected in pairs.

[0015] When using the trace gas metering device in the gold tube thermal simulation experiment, the following steps are adopted:

[0016] S1. Place the gold tube into the limiter, then place the limiter into the cavity and seal the cavity;

[0017] S2. Open the first and second valves and use the vacuum system to evacuate the air from the cavity.

[0018] S3. Close the second valve and open the third valve to slowly fill the cavity with auxiliary gas through the auxiliary gas system;

[0019] S4. Close the third valve, puncture the gold tube with the needle valve, and let it stand to allow the trace amount of gas in the cavity to reach equilibrium.

[0020] S5. Adjust the liquid column in the standard tube to the end of the standard tube closest to the valve system, and use a photoelectric positioner to record the initial position L1 of the liquid column.

[0021] S6. Open the fourth valve. The gas in the cavity pushes the liquid column forward until the position no longer changes. Use the photoelectric positioner to record the liquid column's termination position L2.

[0022] S7. Calculate the volume of trace gas using the readings from the digital calipers and the inner diameter of the standard tube.

[0023] The present invention has the following beneficial effects: Due to the above-mentioned scheme, the device eliminates the risk of mercury pump leakage, making operation safe and convenient; it directly provides the gas volume, rather than determining the gas quantity through the gas pressure, resulting in more accurate results; by using a photoelectric positioner to determine the position of the liquid column before and after movement, and using digital calipers to record the movement distance, and calculating the gas volume, errors caused by human eye reading of pressure are eliminated, achieving a measurement accuracy down to the microliter level, further improving accuracy; the device is simple, low-cost, and does not require a chromatograph, greatly reducing gas measurement costs; after gas measurement, the remaining gas can be extracted using an airtight syringe through a sealing gasket for other analyses; this device is not limited to the measurement of trace gases in gold tube thermal simulation experiments, but can also be applied to the measurement of trace gases in other fields with high accuracy. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the present invention.

[0025] In the diagram: 1-Gas intake system, 11-Sealing assembly, 12-Needle valve, 13-Cavity, 14-Gold tube, 15-Limiter; 2-Vacuum system, 21-Vacuum pump, 22-Pressure gauge; 3-Auxiliary gas system, 31-Auxiliary gas, 32-Pressure reducer; 4-Metering system, 41-Standard tube, 42-Photoelectric positioner, 43-Digital caliper, 44-Railway, 45-Liquid column; 5-Valve system, 51-First valve, 52-Second valve, 53-Third valve, 54-Fourth valve. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings:

[0027] Depend on Figure 1 As shown, a trace gas metering device for a gold tube thermal simulation experiment includes a gas sampling system 1, a vacuum system 2, an auxiliary gas system 3, a metering system 4, and a valve system 5. The gas sampling system 1 and the vacuum system 2, and the gas sampling system 1 and the auxiliary gas system 3 are respectively connected through the valve system 5. The metering system 4 is used to measure the volume of gas discharged from the gas sampling system 1. The gas sampling system 1 and the metering system 4 are connected through the valve system 5. The valve system 5 includes a first valve 51, a second valve 52, a third valve 53, and a fourth valve 54. The four valves are connected in pairs. By opening and closing different valves, the gas sampling system 1 is connected to the vacuum system 2, the auxiliary gas system 3, and the metering system 4, respectively.

[0028] The gas extraction system 1 includes a cavity 13, one end of which is sealed by a sealing assembly 11, and the other end is connected to the first valve 51 in the valve system 5 via a pipeline. A limiter 15 is fixed inside the cavity 13, and a gold tube 14 is fixed inside the limiter 15. A needle valve 12 is connected to the outside of the cavity 13, and the end of the needle valve 12 is located above the gold tube 14. The needle valve 12 can puncture the gold tube 14, allowing the gas inside the gold tube 14 to enter the cavity 13. The upper part of the limiter 15 has a hollow structure, which does not affect the needle valve 12 from puncturing the gold tube 14.

[0029] The vacuum system 2 includes a vacuum pump 21 and a pressure gauge 22. The vacuum pump 21 is connected to the second valve 52 in the valve system 5, and the pressure gauge 22 can detect the pressure status inside the cavity 13. The auxiliary gas system 3 includes an auxiliary gas 31 and a pressure reducer 32. The auxiliary gas 31 is an inert gas, preferably helium, which will not affect subsequent analyses such as gas composition and isotopes. The pressure reducer 32 is connected to the third valve 53 in the valve system 5 and is responsible for slowly releasing the gas and stabilizing the gas flow rate, injecting the auxiliary gas 31 into the cavity 13.

[0030] The metering system 4 includes a standard tube 41, a photoelectric positioner 42, a digital caliper 43, and a track 44. The inner diameter of the standard tube 41 can be changed according to usage requirements. The material of the standard tube 41 should have certain light transmittance characteristics to ensure that the internal liquid column can be measured by optical elements. One end of the standard tube 41 is connected to the fourth valve 54 in the valve system 5. A track 44 is provided between the standard tube 41 and the digital caliper 43, and the standard tube 41, track 44, and digital caliper 43 are parallel and horizontally placed. The photoelectric positioner 42 is connected to the track 44 and is connected to the pointer of the digital caliper 43. A liquid column 45 is provided inside the standard tube 41. The end face of the photoelectric positioner 42 is aligned with the liquid column 45 and moves with the movement of the liquid column 45, simultaneously causing the pointer of the digital caliper 43 to move along the digital caliper 43. The digital caliper 43 records the movement distance, and the gas volume can be obtained by calculating the volume of the cylinder. The metering system 4 can also use other devices for measuring gas volume.

[0031] When using the trace gas metering device in this gold tube thermal simulation experiment, the following steps are adopted:

[0032] S1. Insert the gold tube 14 into the limiter 15, and then insert the limiter 15 into the cavity 13. Seal the cavity 13 by the sealing assembly 11.

[0033] S2. Open the first valve 51 and the second valve 52, and use the vacuum pump 21 in the vacuum system 2 to evacuate the air in the cavity 13 until the pressure gauge 22 indicates that the pressure has reached the limit. At this time, the pressure is negative, usually -0.1MPa.

[0034] S3. Close the second valve 52 and open the third valve 53. Slowly fill the cavity 13 with low-pressure auxiliary gas through the pressure reducer 32 in the auxiliary gas system 3 until the pressure gauge 22 counts zero or a positive value slightly above zero.

[0035] S4. Close the third valve 53, puncture the gold tube 14 with the needle valve 12, and let it stand for a period of time (usually 5-10 minutes) to allow the trace gas in the cavity 13 to reach a state of equilibrium.

[0036] S5. Adjust the liquid column 45 in the standard tube 41 so that it is close to the end of the standard tube 41 near the valve system 5, and use the photoelectric positioner 42 to record the initial position L1 of the liquid column 45.

[0037] S6. Open the fourth valve 54. The gas in the cavity 13 enters the standard tube 41 through the first valve 51 and the fourth valve 54, pushing the liquid column 45 forward until the position no longer changes. At the same time, the photoelectric positioner 42 drives the pointer of the digital caliper 43 to move together. The photoelectric positioner 42 records the end position L2 of the liquid column 45.

[0038] S7. Substitute the reading of the digital caliper 43 (i.e., the value obtained by subtracting L1 from L2) and the inner diameter of the standard tube 41 into the calculation formulas for the cylinder to calculate the volume of the trace gas. Since the pressure inside and outside the cavity is balanced in the initial state, and after the vacuum system evacuates the cavity and then injects auxiliary gas, the pressure inside and outside the cavity is also balanced. Therefore, the gas measured by the metering system is the volume of the trace gas discharged from the gold tube.

Claims

1. A trace gas metering device in a gold tube thermal simulation experiment, comprising a gas taking system (1), a vacuum system (2), an auxiliary gas system (3), a metering system (4) and a valve system (5), characterized in that: The gas taking system (1) and the vacuum system (2), the gas taking system (1) and the auxiliary gas system (3) are connected through the valve system (5) respectively; the metering system (4) is used for metering the gas volume discharged by the gas taking system (1), and the gas taking system (1) and the metering system (4) are connected through the valve system (5); The gas taking system (1) comprises a cavity (13), a limiting piece (15) is fixed in the cavity (13), a gold tube (14) is fixed in the limiting piece (15), a needle valve (12) is connected outside the cavity (13), and the end of the needle valve (12) is located at the upper portion of the gold tube (14); one end of the cavity (13) is sealed through a sealing assembly (11), and the cavity (13) is connected with the valve system (5) through a pipeline; The metering system (4) comprises a standard tube (41) and a digital caliper (43), one end of the standard tube (41) is connected with the valve system (5), a track (44) is arranged between the standard tube (41) and the digital caliper (43), the standard tube (41), the track (44) and the digital caliper (43) are parallel to each other, an optical positioner (42) is connected to the track (44), and the optical positioner (42) is connected with the pointer of the digital caliper (43); the standard tube (41), the track (44) and the digital caliper (43) are horizontally arranged; a liquid column (45) is arranged in the standard tube (41), the optical positioner (42) is aligned with the end face of the liquid column (45), and the optical positioner (42) moves along with the movement of the liquid column (45).

2. The apparatus according to claim 1, wherein: The outer wall of the standard tube (41) is light-transmitting.

3. The apparatus according to claim 1, wherein: The limiting piece (15) is fixed in the cavity (13), and the gold tube (14) is located in the limiting piece (15), and the upper portion of the limiting piece (15) is hollowed out.

4. The apparatus according to claim 3, wherein: The auxiliary gas in the auxiliary gas system (3) is inert gas.

5. The apparatus for measuring trace gases in a gold tube thermal simulation experiment according to any one of claims 1 to 4, characterized in that: The valve system (5) comprises first, second, third and fourth valves (51, 52, 53, 54), and the four valves are connected two by two.

6. The apparatus according to claim 5, wherein: In use, the following steps are adopted: S1, the gold tube (14) is placed in the limiting piece (15), the limiting piece (15) is placed in the cavity (13), and the cavity (13) is sealed; S2, the first valve (51) and the second valve (52) are opened, and the cavity (13) is evacuated by the vacuum system (2); S3, the second valve (52) is closed, the third valve (53) is opened, and the auxiliary gas is slowly filled into the cavity (13) through the auxiliary gas system (3); S4, the third valve (53) is closed, the gold tube (14) is pierced by the needle valve (12), and the cavity (13) is allowed to stand still so that the trace gas in the cavity (13) reaches an equilibrium state; S5, the liquid column (45) in the standard tube (41) is adjusted so that the liquid column (45) reaches the end of the standard tube (41) close to the valve system (5), and the initial position L1 of the liquid column (45) is recorded by the optical positioner (42); S6, the fourth valve (54) is opened, the gas in the cavity (13) pushes the liquid column (45) to move forward until the position no longer changes, and the terminal position L2 of the liquid column (45) is recorded by the optical positioner (42). S7. Calculate the volume of the trace gas by reading the digital caliper (43) and the inner diameter of the standard tube (41).

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