A test system for replacing natural gas hydrate with carbon dioxide, comprising a sample reaction vessel, a sample boundary condition loading device, a methane gas supply device, a carbon dioxide gas supply device, an output article collection and measurement device, and a data acquisition control device;
- the sample reaction vessel comprises a side shrouding, an upper cover plate arranged at a top of the side shrouding and a lower tray arranged at a bottom of the side shrouding;
- the side shrouding, the upper cover and the lower tray form an inner cavity of the vessel;
- a sample-sealing rubber sleeve and a upper sample-sealing plate are arranged in the inner cavity of the vessel, a lower end of the sample-sealing rubber sleeve is hermetically connected to the lower tray, an upper end of the sample-sealing rubber sleeve is hermetically connected to the upper sample-sealing plate, and the sample-sealing rubber sleeve, the upper sample-sealing plate and the lower tray form a sample-sealing space;
- an axial pressure loading plate capable of moving up and down is arranged in the inner cavity of the vessel above the upper sample-sealing plate, and the upper cover plate is provided with an axial pressure loading injection hole;
- the side shrouding is provided with a confining pressure loading injection hole and a product discharge hole and is sleeved with a liquid cooling jacket;
- the product discharge hole penetrates through the sample-sealing rubber sleeve to communicate with the sample-sealing space;
- a methane gas injection pipe penetrates through the upper cover plate, the axial pressure loading plate and the upper sample-sealing plate to extend into the sample-sealing space;
- a carbon dioxide injection pipe penetrates through the lower tray to extend into the sample-sealing space;
- the lower tray is provided with a temperature and pressure sensor for detecting the temperature and pressure in the sample-sealing space;
- the sample boundary condition loading device comprises an axial pressure loading device and a confining pressure loading device;
- the axial pressure loading device and the confining pressure loading device are respectively connected to the axial pressure loading injection hole and the confining pressure loading injection hole via pipelines, the pipeline between the axial pressure loading device and the axial pressure loading injection hole is provided with an axial pressure transmitter, and the pipeline between the confining pressure loading device and the confining pressure loading injection hole is provided with a confining pressure transmitter;
- the methane gas supply device comprises a methane gas cylinder;
- a pipeline, connected to the methane gas injection pipe, of the methane gas cylinder is provided with a first gas booster pump, a first constant-pressure or constant-rate gas pump and a first gas storage tank in sequence, and the first gas booster pump is close to the methane gas cylinder;
- the first gas storage tank is placed in a first cold bath device, and the first cold bath device is connected to a first temperature control device;
- the pipeline between the first gas storage tank and the methane gas injection pipe is provided with a first gas pressure transmitter;
- the carbon dioxide gas supply device comprises a carbon dioxide gas cylinder;
- a pipeline, connected to the carbon dioxide injection pipe, of the carbon dioxide gas cylinder is provided with a second gas booster pump, a second constant-pressure or constant-rate gas pump and a second gas storage tank in sequence, and the second gas booster pump is close to the carbon dioxide gas cylinder;
- the second gas storage tank is placed in a second cold bath device, the second cold bath device is connected to a second temperature control device, and the pipeline between the second gas storage tank and the carbon dioxide injection pipe is provided with a second gas pressure transmitter;
- the output article collection and measurement device comprises a pressure control valve, preset pressurizing equipment, and an output article collection and measurement assembly;
- the product discharge hole is connected to the pressure control valve via a pipeline, the pressure control valve is connected to the output article collection and measurement assembly via a pipeline, the output article collection and measurement assembly is configured for collecting and measuring the output article, and the pressure control valve is also connected to the preset pressurizing equipment via a pressure switch;
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- the temperature and pressure sensor, the axial pressure loading device, the confining pressure loading device, the axial pressure transmitter, the confining pressure transmitter, the first constant-pressure or constant-rate gas pump, the second constant-pressure or constant-rate gas pump, the first temperature control device, the second temperature control device, the first gas pressure transmitter, the second gas pressure transmitter and the output article collection and measurement assembly are electrically connected to the data acquisition control device.