Experimental Device for Measuring Diffusion Coefficient of Natural Gas

Abstract

The present invention discloses a new experimental device for measuring a diffusion coefficient of natural gas, mainly including a new core holder, a differential pressure sensor, pressure gauges, multiport valves, a confining pressure pump, a vacuum pump, a hydrocarbon gas source, a nitrogen gas source, a gas chromatograph, an intermediate container, sample chambers, a pressure stabilizing device, and pressure-sensitive alarm devices. A rubber sleeve of the new core holder can prevent a core from being stuck in the holder during core replacement due to an improper operation. The configured pressure stabilizing device is connected to the sample chambers, to ensure stable internal pressure in the chambers after sampling. In this way, one experimental variable is omitted, and an experimental result is more accurate and reliable. If gas leakage occurs. A sensor device can sense the gas leakage in time and sends an alarm to a mobile device of an experimenter.

Claims

1. A new experimental device for measuring a diffusion coefficient of natural gas, comprising a gas chromatograph, a first measurement valve, a second measurement valve, a differential pressure sensor, a first sample chamber, a second sample chamber, a first pressure gauge, a second pressure gauge, a core holder, a first sampling valve, a second sampling valve, a confining pressure pump, a valve, a piston-type intermediate container, a high-precision constant-speed constant-pressure pump, a vacuum pump, a first multiport valve, a second multiport valve, a first gas source cylinder, a second gas source cylinder, a first pressure-sensitive alarm device, and a second pressure-sensitive alarm device, wherein the gas chromatograph is connected to both the first measurement valve and the second measurement valve; the other ends of the first measurement valve and the second measurement valve are respectively connected to the first sample chamber and the second sample chamber; the first sample chamber and the second sample chamber are respectively connected to the first sampling valve and the second sampling valve; the other end of the first sampling valve is connected to the first pressure gauge, a first end of the differential pressure sensor, the first pressure-sensitive alarm device, and a first end of the core holder; the other end of the second sampling valve is connected to the second pressure gauge, a second end of the differential pressure sensor, the second pressure-sensitive alarm device, and a second end of the core holder; one end of the valve is connected between the first pressure gauge and the second pressure gauge; the other end of the valve is connected to one end of the piston-type intermediate container; the confining pressure pump is connected to the middle part of the core holder; the other end of the piston-type intermediate container is connected to the high-precision constant-speed constant-pressure pump; third ends of the first sample chamber and the second sample chamber are respectively connected to first ends of the first multiport valve and the second multiport valve; second ends of the first multiport valve and the second multiport valve are connected to the vacuum pump; a third end of the first multiport valve is connected to the first gas source cylinder; and a third end of the second multiport valve is connected to the second gas source cylinder.

2. The new experimental device for measuring a diffusion coefficient of natural gas according to claim 1, wherein a rubber sleeve is disposed on a gasket of a plug at one end of the core holder.

3. The new experimental device for measuring a diffusion coefficient of natural gas according to claim 1, wherein the rubber sleeve on the core holder can be directly used to load a core, and can meet both confining pressure loading and heating requirements during an experiment.

4. The new experimental device for measuring a diffusion coefficient of natural gas according to claim 1, wherein a pipeline is externally connected between the sample chamber and the core holder to connect to a pressure regulating system.

5. The new experimental device for measuring a diffusion coefficient of natural gas according to claim 1, wherein the pressure-sensitive alarm device comprises a pressure sensor and a single-chip microcomputer; the sensor converts a pressure signal into an electrical signal and sends the electrical signal to the single-chip microcomputer; and the single-chip microcomputer can directly communicate with a Global System for Mobile Communications (GSM) module to send preset alarm information to a mobile device of an experimenter.

6. The new experimental device for measuring a diffusion coefficient of natural gas according to claim 1, wherein a pressure regulating system comprises one piston-type intermediate container and one high-precision constant-speed constant-pressure pump.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0017] FIG. 1 is a schematic diagram of an overall structure according to the present invention;

[0018] FIG. 2 is a structural schematic diagram of a pressure-sensitive alarm device according to the present invention;

[0019] FIG. 3 is a structural schematic diagram of a core holder according to the present invention; and

[0020] FIG. 4 is a sectional view of a core holder according to the present invention.

[0021] In the figures: 1gas chromatograph, 2first measurement valve, 3second measurement valve, 4differential pressure sensor, 5first sample chamber, 6second sample chamber, 7first pressure gauge, 8second pressure gauge, 9core holder, 10first sampling valve, 11second sampling valve, 12confining pressure pump, 13valve, 14piston-type intermediate container, 15high-precision constant-speed constant-pressure pump, 16vacuum pump, 17first multiport valve, 18second multiport valve, 19first gas source cylinder, 20second gas source cylinder, 21first pressure-sensitive alarm device, 22second pressure-sensitive alarm device, 211pressure sensor, 212single-chip microcomputer, 213mobile device, 91rubber sleeve, 92gasket, and 93plug.

DETAILED DESCRIPTION

[0022] The present invention is further described in detail with reference to accompanying drawings.

[0023] As shown in FIG. 1, the present invention includes a gas chromatograph 1, a first measurement valve 2, a second measurement valve 3, a differential pressure sensor 4, a first sample chamber 5, a second sample chamber 6, a first pressure gauge 7, a second pressure gauge 8, a core holder 9, a first sampling valve 10, a second sampling valve 11, a confining pressure pump 12, a valve 13, a piston-type intermediate container 14, a high-precision constant-speed constant-pressure pump 15, a vacuum pump 16, a first multiport valve 17, a second multiport valve 18, a first gas source cylinder 19, a second gas source cylinder 20, a first pressure-sensitive alarm device 21, and a second pressure-sensitive alarm device 22, where the gas chromatograph is connected to both the first measurement valve and the second measurement valve; the other ends of the first measurement valve and the second measurement valve are respectively connected to the first sample chamber and the second sample chamber; the first sample chamber and the second sample chamber are respectively connected to the first sampling valve and the second sampling valve; the other end of the first sampling valve is connected to the first pressure gauge, a first end of the differential pressure sensor, the first pressure-sensitive alarm device, and a first end of the core holder; the other end of the second sampling valve is connected to the second pressure gauge, a second end of the differential pressure sensor, the second pressure-sensitive alarm device, and a second end of the core holder; one end of the valve is connected between the first pressure gauge and the second pressure gauge; the other end of the valve is connected to one end of the piston-type intermediate container; the confining pressure pump is connected to the middle part of the core holder; the other end of the piston-type intermediate container is connected to the high-precision constant-speed constant-pressure pump; third ends of the first sample chamber and the second sample chamber are respectively connected to first ends of the first multiport valve and the second multiport valve; second ends of the first multiport valve and the second multiport valve are connected to the vacuum pump; a third end of the first multiport valve is connected to the first gas source cylinder; and a third end of the second multiport valve is connected to the second gas source cylinder.

[0024] A rubber sleeve 91 is disposed on a gasket 92 of a plug 93 at one end of the core holder.

[0025] The rubber sleeve on the core holder can be directly used to load a core, and can meet both confining pressure loading and heating requirements during an experiment.

[0026] A pipeline is externally connected between the sample chamber and the core holder to connect to a pressure regulating system.

[0027] The pressure-sensitive alarm device includes a pressure sensor 211 and a single-chip microcomputer 212; the sensor converts a pressure signal into an electrical signal and sends the electrical signal to the single-chip microcomputer; and the single-chip microcomputer can directly communicate with a GSM module to send preset alarm information to a mobile device 213 of an experimenter.

[0028] Further, a pressure regulating system includes one piston-type intermediate container and one high-precision constant-speed constant-pressure pump; and the pressure regulating system can not only directly change internal pressure but also keep stable internal pressure during the experiment.

[0029] An experimental method based on the device includes the following steps:

[0030] Step 1: Load a core. The plug at one end, provided with the rubber sleeve, of the core holder 9 is taken out, and the standard core column is screwed into the rubber sleeve to load the plug into the holder.

[0031] Step 2: Set an experimental condition. Confining pressure and temperature required for the experiment are set according to the industry standard.

[0032] Step 3: Set internal pressure. The multiport valves 17 and 18 are opened, while other valves are closed. Corresponding gases are injected into the two sample chambers according to the experimental condition, and then the valves are closed. Pressure of the constant-speed constant-pressure pump is set to be the same as the internal pressure, and the valve 13 is closed. A lower pressure limit of the pressure sensor is set according to the internal pressure, and then the experiment is carried out, where the gases diffuse themselves.

[0033] Step 4: Conduct sampling and measurement. Sampling and measurement are conducted at a regular interval according to the industry standard. After the whole system is vacuumized, the sampling valves 10 and 11 are opened to allow samples to enter the sample chambers 5 and 6. Then, the measurement valves 2 and 3 are opened to allow the sample gases to enter the chromatograph 1 for component analysis.

[0034] Step 5: Recover the internal pressure. Because some samples are taken out, the internal pressure is decreased. The sampling valves 10 and 11 are closed, and then the valve 13 is opened. The constant-speed constant-pressure pump automatically increases the pressure to the original internal pressure before sampling. The valve is closed after the pressure is stable, and the gases continue to diffuse.

[0035] Step 6: Calculate a diffusion coefficient. After sampling is conducted several times according to the previous steps, a diffusion coefficient is calculated according to the industry standard.

[0036] The foregoing displays and describes the basic principles, main features, and advantages of the present invention. It should be understood by those skilled in the art that, the present invention is not limited by the aforementioned embodiments. The aforementioned embodiments and the description only illustrate the principle of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications all fall within the claimed scope of the present invention. The protection scope of the present invention is defined by the appended claims and their equivalents.