Dense-phase carbon dioxide and supercritical natural gas mixing device and method

Abstract

The invention relates to a dense-phase carbon dioxide and supercritical natural gas mixing device and method, and the device comprises a dense-phase carbon dioxide preparation system, a supercritical natural gas supply system, a mixing replacement system and a mixed property detection system. The dense-phase carbon dioxide preparation system and the supercritical natural gas supply system are respectively used for preparing dense-phase carbon dioxide fluid and supplying supercritical natural gas fluid; the mixing replacement system is used for mixing dense-phase carbon dioxide fluid and supplied supercritical natural gas fluid in the forms of static mixing, jet mixing and buffer tank mixing; and the mixed property detection system is used for detecting the content of carbon dioxide in the mixed fluid mixed in different mixing forms and the pressure and temperature of the mixed fluid. The method comprises the following steps: preparing dense-phase carbon dioxide; supplying supercritical natural gas; dense-phase carbon dioxide and supercritical natural gas are mixed to research the influence of different mixing forms on the properties of the mixed dense-phase carbon dioxide and supercritical natural gas.

Description

Technical Field

[0001] The present invention relates to a device and method for mixing dense-phase carbon dioxide and supercritical natural gas. Background Art

[0002] With the popularization of Carbon Capture, Utilization and Storage (CCUS), separating CO2 from industrial processes and energy utilization and then using it or injecting it into the formation can not only achieve CO2 emission reduction and permanent storage, but also improve the recovery rate of oil and gas in crude oil and condensate gas reservoirs.

[0003] For the injection of the mixture of carbon dioxide and natural gas into the formation, it usually shows supercritical / dense-phase transportation. The economy of mixing carbon dioxide and natural gas and then entering the compressor is significantly better than separately pressurizing carbon dioxide and associated gas using injection compressors, mixing them after reaching the injection pressure and then injecting them into the formation. The two injection compressors only handle a single medium, which can ensure the stable operation of the equipment, but separate pressurization increases the number of equipment and significantly increases the equipment investment. The technical difficulty lies in that the injection compressor is applicable to the range where the compression factor Z of the medium system is greater than 0.5. However, for the mixing process of dense-phase carbon dioxide and supercritical natural gas, there may be problems of uneven distribution, which may lead to compressors that do not meet the applicable conditions of the compression factor. Due to the obvious differences in phase characteristics and density between dense-phase carbon dioxide and supercritical natural gas, it may not be easy to mix them evenly. Among them, supercritical natural gas is prepared from Compressed Natural Gas (CNG). Compressed natural gas refers to gaseous natural gas compressed to a pressure greater than or equal to 10 MPa and not greater than 25 MPa, which is pressurized and stored in a container in a gaseous state.

[0004] In summary, there is currently a lack of a device for studying the influence of different mixing forms on the properties of the mixture of dense-phase carbon dioxide and supercritical natural gas. Summary of the Invention

[0005] In view of the above problems, the object of the present invention is to provide a device and method for mixing dense-phase carbon dioxide and supercritical natural gas to solve the problem of the lack of a device for studying the influence of different mixing forms on the properties of the mixture of dense-phase carbon dioxide and supercritical natural gas.

[0006] To achieve the above object, the present invention adopts the following technical solutions: In the first aspect, the present invention discloses a device for mixing dense-phase carbon dioxide and supercritical natural gas, including a dense-phase carbon dioxide preparation system, a supercritical natural gas supply system, a mixing replacement system, and a property detection system for the mixture after mixing. The blending and replacement system includes a static mixer, an injection mixer, and a buffer tank. The static mixer, the injection mixer, and the buffer tank each include a cylinder body. The two ends of the cylinder body are respectively set as an inlet end and an outlet end. Flange interfaces are respectively configured at the inlet end and the outlet end. A second medium inlet is provided at a position on the cylinder body close to the inlet end. The inlet end of the cylinder body of the static mixer, the injection mixer, or the buffer tank is butt - jointed with the outlet of the supercritical natural gas supply system through a flange. The second medium inlet of the cylinder body of the static mixer, the injection mixer, or the buffer tank is butt - jointed with the outlet of the dense - phase carbon dioxide preparation system. The outlet end of the cylinder body of the static mixer, the injection mixer, or the buffer tank is butt - jointed with the inlet of the property detection system after blending through a flange. Among them, the dense - phase carbon dioxide preparation system and the supercritical natural gas supply system are respectively used to prepare dense - phase carbon dioxide fluid and supply supercritical natural gas fluid. The static mixer, the injection mixer, and the buffer tank are respectively used to mix the dense - phase carbon dioxide fluid and the supplied supercritical natural gas fluid in the forms of static mixing, injection mixing, and buffer - tank mixing. The property detection system after blending is used to detect the carbon dioxide content, the pressure, and the temperature of the mixed fluid after blending under different mixing forms.

[0007] Further, the dense - phase carbon dioxide preparation system includes a carbon dioxide flange joint, a first pressure reducing valve, a first heat - tracing belt, and a first flowmeter. The first heat - tracing belt includes a heat - tracing pipeline. An electric heating device is built in the heat - tracing pipeline. The heat - tracing pipeline is configured with a first temperature control instrument. The carbon dioxide flange joint is used to butt - joint the equipment storing high - pressure dense - phase carbon dioxide fluid. The carbon dioxide flange joint is communicated with the inlet of the heat - tracing pipeline of the first heat - tracing belt through a first front pipeline. The outlet of the heat - tracing pipeline of the first heat - tracing belt is butt - jointed with the inlet of the first flowmeter. The outlet of the first flowmeter is provided with a first rear pipeline. The outlet of the first rear pipeline is used to butt - joint with the second medium inlet of the cylinder body of the static mixer, the injection mixer, or the buffer tank. The first pressure reducing valve is arranged on the first front pipeline that communicates the carbon dioxide flange joint with the inlet of the heat - tracing pipeline of the first heat - tracing belt.

[0008] Furthermore, a first one-way valve is provided on a first rear pipeline that is connected between the outlet of the first flow meter and the second medium inlet of the cylinder of the static mixer, the jet mixer or the buffer tank.

[0009] Furthermore, a first pressure gauge is provided on the heating pipe of the first heating belt.

[0010] Furthermore, the supercritical natural gas supply system includes a compressed natural gas tanker, a second pressure reducing valve, a second heating belt and a second flow meter. The second heating belt comprises a heating pipe, the heating pipe is equipped with an electric heating device, and the heating pipe is equipped with a second temperature control instrument. The compressed natural gas tank truck contains high-pressure compressed natural gas. The outlet of the CNG tank truck is connected to the inlet of the heating pipeline of the second heating belt through a second front pipeline; The outlet of the heating pipe of the second heating tape is connected to the inlet of the second flow meter; The outlet of the second flow meter is provided with a second rear pipe, and the outlet of the second rear pipe is used to connect with the second medium inlet of the cylinder of the static mixer, the jet mixer or the buffer tank; The second pressure reducing valve is disposed on a second front pipeline of the CNG tank truck connected to the inlet of the heating pipeline of the second heating belt.

[0011] Furthermore, a second one-way valve is provided on a second rear pipeline in communication with the outlet of the second flow meter and the inlet end of the cylinder of the static mixer, the jet mixer or the buffer tank.

[0012] Furthermore, a second pressure gauge is provided on the heating pipe of the second heating belt.

[0013] Furthermore, the mixed property detection system includes a hollow pipe, a top carbon dioxide analyzer, a bottom carbon dioxide analyzer, an outlet pressure gauge and a temperature sensor. The inlet end of the hollow pipe is connected to the outlet end of the cylinder of the static mixer, jet mixer or buffer tank of the blending and replacement system through a flange; The top carbon dioxide analyzer and the bottom carbon dioxide analyzer are respectively arranged at the top and the bottom of the hollow pipe near the outlet end of the hollow pipe; The outlet pressure gauge and the temperature sensor are respectively arranged at ports at the outlet end of the hollow pipe; The hollow pipe is used to further fully mix and develop the mixed fluid after the dense phase carbon dioxide and supercritical natural gas are mixed; The top carbon dioxide analyzer and the bottom carbon dioxide analyzer respectively collect the content of carbon dioxide in the mixed fluid after the dense-phase carbon dioxide and supercritical natural gas near the top and bottom in the hollow pipe are mixed; The outlet pressure gauge is used to collect the pressure of the mixed fluid at the outlet end of the hollow pipe; The temperature sensor is used to collect the temperature of the mixed fluid at the outlet end of the hollow pipe.

[0014] Further, a pneumatic valve is connected to the outlet end of the hollow pipe, and the pneumatic valve is provided with a discharge port.

[0015] In a second aspect, the present invention also discloses a method for mixing dense-phase carbon dioxide and supercritical natural gas. Using the above device, the method includes: Step A: Prepare dense-phase carbon dioxide; Step B: Supply supercritical natural gas; Step C: Mix the dense-phase carbon dioxide and the supercritical natural gas to study the influence of different mixing forms on the properties of the mixture of dense-phase carbon dioxide and supercritical natural gas.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention discloses a device for mixing dense-phase carbon dioxide and supercritical natural gas, which includes a dense-phase carbon dioxide preparation system, a supercritical natural gas supply system, a mixing and replacement system, and a property detection system for the mixed fluid after mixing. The mixing and replacement system includes a static mixer, an injection mixer, and a buffer tank. The static mixer, the injection mixer, and the buffer tank each include a cylinder body, and the two ends of the cylinder body are respectively set as an inlet end and an outlet end. Flange interfaces are respectively configured at the inlet end and the outlet end, and a second medium inlet is arranged on the cylinder body near the inlet end. The inlet end of the cylinder body of the static mixer, the injection mixer, or the buffer tank is butt-connected to the outlet of the supercritical natural gas supply system through a flange; the second medium inlet of the cylinder body of the static mixer, the injection mixer, or the buffer tank is butt-connected to the outlet of the dense-phase carbon dioxide preparation system; the outlet end of the cylinder body of the static mixer, the injection mixer, or the buffer tank is butt-connected to the inlet of the property detection system for the mixed fluid after mixing through a flange. Among them, the dense-phase carbon dioxide preparation system and the supercritical natural gas supply system are respectively used to prepare dense-phase carbon dioxide fluid and supply supercritical natural gas fluid; the static mixer, the injection mixer, and the buffer tank are respectively used to mix the dense-phase carbon dioxide fluid and the supplied supercritical natural gas fluid in the forms of static mixing, injection mixing, and buffer tank mixing; the property detection system for the mixed fluid after mixing is used to detect the carbon dioxide content, pressure, and temperature of the mixed fluid after mixing in different mixing forms. The present invention discloses a device for mixing dense-phase carbon dioxide and supercritical natural gas, which can be used to study the influence of different mixing forms on the properties of the mixture of dense-phase carbon dioxide and supercritical natural gas.

[0017] (2) The present invention discloses a method for mixing dense-phase carbon dioxide and supercritical natural gas, which includes: preparing dense-phase carbon dioxide; supplying supercritical natural gas; mixing dense-phase carbon dioxide and supercritical natural gas to study the influence of different mixing forms on the properties of the mixture of dense-phase carbon dioxide and supercritical natural gas. The present invention discloses a method for mixing dense-phase carbon dioxide and supercritical natural gas, which lays a foundation for the adaptive research on the mixing properties, flow conditions, and equipment operation of the mixture of dense-phase carbon dioxide and supercritical natural gas. Description of the Drawings

[0018] Figure 1 is the overall structural schematic diagram of the device for mixing dense-phase carbon dioxide and supercritical natural gas provided in Embodiment 1 of the present invention; Figure 2 is the structural schematic diagram of the static mixer provided in Embodiment 1 of the present invention; Figure 3 is the structural schematic diagram of the dense-phase carbon dioxide preparation system provided in Embodiment 1 of the present invention; Figure 4 is the structural schematic diagram of the supercritical natural gas supply system provided in Embodiment 1 of the present invention; Figure 5 It is a schematic structural diagram of the property detection system after blending provided in Embodiment 1 of the present invention.

[0019] Explanation of reference numerals: 1 - Dense-phase carbon dioxide preparation system, 10 - Carbon dioxide flange joint, 11 - First pressure reducing valve, 12 - First heat tracing tape, 120 - First temperature control instrument, 13 - First flowmeter, 14 - First check valve, 15 - First pressure gauge; 2 - Supercritical natural gas supply system, 20 - Compressed natural gas tanker, 21 - Second pressure reducing valve, 22 - Second heat tracing tape, 220 - Second temperature control instrument, 23 - Second flowmeter, 24 - Second check valve, 25 - Second pressure gauge; 3 - Blending and replacement system, 30 - Cylinder body, 31 - Inlet end, 32 - Outlet end, 33 - Second medium inlet; 4 - Property detection system after blending, 41 - Hollow pipeline, 421 - Top carbon dioxide analyzer, 422 - Bottom carbon dioxide analyzer, 43 - Outlet pressure gauge, 44 - Temperature sensor, 45 - Pneumatic valve. Detailed implementation mode

[0020] Hereinafter, the exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present invention can be more thoroughly understood and the scope of the present invention can be fully conveyed to those skilled in the art.

[0021] Embodiment 1: A blending device for dense-phase carbon dioxide and supercritical natural gas Embodiment 1 of the present invention provides a blending device for dense-phase carbon dioxide and supercritical natural gas, which is used to study the influence of different mixing forms on the properties of the blend of dense-phase carbon dioxide and supercritical natural gas. The structure and connection relationship thereof will be described in detail below.

[0022] Referring to Figure 1 , this blending device for dense-phase carbon dioxide and supercritical natural gas includes a dense-phase carbon dioxide preparation system 1, a supercritical natural gas supply system 2, a blending and replacement system 3, and a property detection system 4 after blending. The blending and replacement system 3 includes a static mixer, an injection mixer, and a buffer tank. The static mixer, the injection mixer, and the buffer tank each include a cylinder body 30. The two ends of the cylinder body 30 are respectively set as an inlet end 31 and an outlet end 32. The inlet end 31 and the outlet end 32 are respectively configured with flange plate interfaces. A second medium inlet 33 is provided on the cylinder body near the inlet end 31, as Figure 2 shown; The inlet end 31 of the cylinder body of the static mixer, the injection mixer or the buffer tank is butt-jointed with the outlet of the supercritical natural gas supply system 2 through a flange; The second medium inlet 33 of the cylinder body of the static mixer, the injection mixer or the buffer tank is docked with the outlet of the dense-phase carbon dioxide preparation system 1; The outlet end 32 of the cylinder body of the static mixer, the injection mixer or the buffer tank is butt-jointed with the inlet of the blended property detection system 4 through a flange; Among them, the dense-phase carbon dioxide preparation system 1 and the supercritical natural gas supply system 2 are respectively used to prepare dense-phase carbon dioxide fluid and supply supercritical natural gas fluid; The static mixer, the injection mixer and the buffer tank are respectively used to mix the dense-phase carbon dioxide fluid and the supplied supercritical natural gas fluid in the forms of static mixing, injection mixing and buffer tank mixing; The blended property detection system 4 is used to detect the carbon dioxide content, pressure and temperature of the blended fluid under different mixing forms.

[0023] When it is necessary to study the influence of different mixing forms on the properties of the blend of dense-phase carbon dioxide and supercritical natural gas, by disassembling and replacing the static mixer, the injection mixer and the buffer tank, the replacement of the static mixing form, the injection mixing form and the buffer tank mixing form is realized.

[0024] Among them, the inlet end 31, the outlet end 32 and the second medium inlet 33 of the cylinder bodies of the static mixer, the injection mixer and the buffer tank are respectively connected in a detachable manner. For example, the inlet end 31 is butt-jointed with the outlet of the supercritical natural gas supply system 2 through a flange, the outlet end 32 is butt-jointed with the inlet of the blended property detection system 4 through a flange, and the second medium inlet 33 is docked with the outlet of the dense-phase carbon dioxide preparation system 1.

[0025] Specifically, a spiral stirrer is fixed inside the cylinder body of the static mixer, as Figure 2 shown, to realize the spiral static mixing of the fluid inside the spiral stirrer. Since the static mixer, the injection mixer and the buffer tank are all prior arts, they will not be elaborated here.

[0026] Reference Figure 3 , the dense-phase carbon dioxide preparation system 1 includes a carbon dioxide flange joint 10, a first pressure reducing valve 11, a first heating tape 12 and a first flow meter 13, The first heating tape 12 includes a heating pipe, the heating pipe is internally provided with an electric heating device, and the heating pipe is configured with a first temperature control instrument 120, The carbon dioxide flange joint 10 is used to dock with the equipment storing high-pressure dense-phase carbon dioxide fluid; The carbon dioxide flange joint 10 is communicated with the inlet of the heat tracing pipeline of the first heat tracing belt 12 through a first front pipeline; The outlet of the heat tracing pipeline of the first heat tracing belt 12 is docked with the inlet of the first flowmeter 13; A first rear pipeline is arranged at the outlet of the first flowmeter 13, and the outlet of the first rear pipeline is used to be docked with the second medium inlet 33 of the cylinder body of the static mixer, the injection mixer or the buffer tank; The first pressure reducing valve 11 is arranged on the first front pipeline where the carbon dioxide flange joint 10 is communicated with the inlet of the heat tracing pipeline of the first heat tracing belt 12.

[0027] In order to ensure that the medium flows from the outlet of the dense-phase carbon dioxide preparation system 1 into the second medium inlet 33 and prevent reverse flow, a first one-way valve 14 is arranged on the first rear pipeline where the outlet of the first flowmeter 13 is communicated with the second medium inlet 33 of the cylinder body of the static mixer, the injection mixer or the buffer tank.

[0028] In order to ensure that the high-pressure dense-phase carbon dioxide fluid flowing out of the carbon dioxide flange joint 10 meets the pressure requirement, a first pressure gauge 15 is arranged on the heat tracing pipeline of the first heat tracing belt 12.

[0029] Reference Figure 4 As shown in, the supercritical natural gas supply system 2 includes a compressed natural gas tanker 20, a second pressure reducing valve 21, a second heat tracing belt 22 and a second flowmeter 23. The second heat tracing belt 22 includes a heat tracing pipeline, an electric heating device is arranged inside the heat tracing pipeline, and the heat tracing pipeline is configured with a second temperature control instrument 220. The compressed natural gas tanker 20 stores high-pressure compressed natural gas in advance; The outlet of the compressed natural gas tanker 20 is communicated with the inlet of the heat tracing pipeline of the second heat tracing belt 22 through a second front pipeline; The outlet of the heat tracing pipeline of the second heat tracing belt 22 is docked with the inlet of the second flowmeter 23; A second rear pipeline is arranged at the outlet of the second flowmeter 23, and the outlet of the second rear pipeline is used to be docked with the second medium inlet 33 of the cylinder body of the static mixer, the injection mixer or the buffer tank; The second pressure reducing valve 21 is arranged on the second front pipeline where the compressed natural gas tanker 20 is communicated with the inlet of the heat tracing pipeline of the second heat tracing belt 22.

[0030] To ensure that the medium flows from the outlet of the second flowmeter 23 into the static mixer, injection mixer or buffer tank of the blending and replacement system 3 and reverse flow is prohibited, a second one-way valve 24 is provided on the second rear pipeline where the outlet of the second flowmeter 23 is connected to the inlet end 31 of the cylinder body of the static mixer, the injection mixer or the buffer tank.

[0031] To ensure that the high-pressure compressed natural gas flowing out of the compressed natural gas tanker 20 meets the pressure requirements, a second pressure gauge 25 is provided on the tracing pipeline of the second tracing belt 12.

[0032] Reference Figure 5 , the property detection system 4 after blending includes a hollow pipeline 41, a top carbon dioxide analyzer 421, a bottom carbon dioxide analyzer 422, an outlet pressure gauge 43 and a temperature sensor 44. Specifically, the diameter of the hollow pipeline 41 is 50 mm and the length is 10 m.

[0033] The inlet end of the hollow pipeline 41 is connected to the outlet end 32 of the cylinder body 30 of the static mixer, injection mixer or buffer tank of the blending and replacement system 3 through a flange. The top carbon dioxide analyzer 421 and the bottom carbon dioxide analyzer 422 are respectively arranged at the top and bottom of the hollow pipeline 41 near the outlet end of the hollow pipeline 41. The outlet pressure gauge 43 and the temperature sensor 44 are respectively arranged at the port of the outlet end of the hollow pipeline 41. Among them, the hollow pipeline 41 is used for the mixed fluid after the blending of dense-phase carbon dioxide and supercritical natural gas to be further fully mixed and developed. The top carbon dioxide analyzer 421 and the bottom carbon dioxide analyzer 422 respectively collect the content of carbon dioxide in the mixed fluid after the blending of dense-phase carbon dioxide and supercritical natural gas near the top and bottom in the hollow pipeline 41. The outlet pressure gauge 43 is used to collect the pressure of the mixed fluid at the outlet end of the hollow pipeline 41. The temperature sensor 44 is used to collect the temperature of the mixed fluid at the outlet end of the hollow pipeline 41.

[0034] For the convenience of drainage and venting, continue to refer to Figure 5 , the outlet end of the hollow pipeline 41 is connected to a pneumatic valve 45, and the pneumatic valve 45 is configured with a discharge port.

[0035] Example 2: A method for blending dense-phase carbon dioxide and supercritical natural gas Example 2 of the present invention provides a method for mixing dense-phase carbon dioxide and supercritical natural gas. Using the mixing device for dense-phase carbon dioxide and supercritical natural gas provided in Example 1, this method includes the following steps: Step A: Prepare dense-phase carbon dioxide, including the following steps: Step A1: The carbon dioxide flange joint 10 receives high-pressure dense-phase carbon dioxide fluid. Step A2: The high-pressure dense-phase carbon dioxide fluid is decompressed by the first pressure reducing valve 11 to become low-pressure dense-phase carbon dioxide fluid. Step A3: The low-pressure dense-phase carbon dioxide fluid is heated by the first heating tape 12 and its temperature rises to become high-temperature and low-pressure dense-phase carbon dioxide fluid. Step A4: Under the action of the first flowmeter 13, the high-temperature and low-pressure dense-phase carbon dioxide fluid outputs high-temperature and low-pressure dense-phase carbon dioxide fluid that meets the set flow rate, that is, dense-phase carbon dioxide fluid.

[0036] Step B: Supply supercritical natural gas, including the following steps: Step B1: The high-pressure compressed natural gas pre-stored in the compressed natural gas tanker 20 is decompressed by the second pressure reducing valve 21 to become low-pressure compressed natural gas. Step B2: The low-pressure compressed natural gas is heated by the second heating tape 22 and its temperature rises to become high-temperature and low-pressure compressed natural gas. Step B3: Under the action of the second flowmeter 23, the high-temperature and low-pressure compressed natural gas outputs high-temperature and low-pressure compressed natural gas that meets the set flow rate, that is, supercritical natural gas. Step C: Mix dense-phase carbon dioxide and supercritical natural gas, and study the influence of different mixing forms on the properties of the mixture of dense-phase carbon dioxide and supercritical natural gas, including the following steps: Step C1: Study the influence of the static mixing form on the properties of the mixture of dense-phase carbon dioxide and supercritical natural gas, including the following steps: Keep the pneumatic valve 45 in the open state. The high-temperature and low-pressure dense-phase carbon dioxide fluid that meets the set flow rate and the high-temperature and low-pressure compressed natural gas of the flow rate enter the static mixer through the first inlet and the second inlet of the static mixer respectively for mixing, and the mixed fluid after mixing dense-phase carbon dioxide and supercritical natural gas is obtained. The mixed fluid after mixing dense-phase carbon dioxide and supercritical natural gas passes through the hollow pipe 41 of the property detection system 4 for mixing. The carbon dioxide analyzers at the top and bottom of the hollow pipe 41 collect the content of carbon dioxide in the mixed fluid after mixing dense-phase carbon dioxide and supercritical natural gas respectively. When passing through the outlet end of the hollow pipe 41, the outlet pressure gauge 43 collects the pressure of the mixed fluid, and the temperature sensor 44 collects the temperature of the mixed fluid.

[0037] Step C2: Study the influence of the jet mixing form on the properties of the mixture of dense-phase carbon dioxide and supercritical natural gas, including the following steps: Adjust the first pressure reducing valve 11 of the dense-phase carbon dioxide preparation system 1 and the second pressure reducing valve 21 of the supercritical natural gas supply system 2 to 0, and close the output of the fluid to the compressed natural gas supply system and the dense-phase carbon dioxide preparation system 1. Remove the static mixer and replace it with a jet mixer. Keep the pneumatic valve in the open state, repeat Step C1, and measure the carbon dioxide content, the pressure, and the temperature of the mixed fluid after mixing again. Step C3: Study the influence of the buffer tank mixing form on the properties of the mixture of dense-phase carbon dioxide and supercritical natural gas, including the following steps: Adjust the first pressure reducing valve 11 of the dense-phase carbon dioxide preparation system 1 and the second pressure reducing valve 21 of the supercritical natural gas supply system 2 to 0, and close the output of the fluid to the dense-phase carbon dioxide preparation system 1 and the supercritical natural gas supply system 2. Remove the jet mixer and replace it with buffer tank mixing. Keep the pneumatic valve in the open state, repeat Step C1, and measure the carbon dioxide content, the pressure, and the temperature of the mixed fluid after mixing again.

[0038] Step C4: Compare the carbon dioxide content, the pressure, and the temperature of the mixed fluid after mixing under different mixing forms, and judge the mixing uniformity accordingly.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. However, such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dense phase carbon dioxide and supercritical natural gas mixing device, characterized in that: The invention comprises a dense phase carbon dioxide preparation system (1), a supercritical natural gas supply system (2), a blending and replacement system (3) and a post-blending property detection system (4). The blending and replacement system (3) comprises a static mixer, a jet mixer and a buffer tank, wherein the static mixer, the jet mixer and the buffer tank each comprise a cylinder (30), wherein two ends of the cylinder (30) are respectively arranged as an inlet end (31) and an outlet end (32), wherein the inlet end (31) and the outlet end (32) are respectively provided with flange interfaces, and a second medium inlet (33) is arranged at a position close to the inlet end (31) on the cylinder; The inlet end (31) of the cylinder of the static mixer, the jet mixer or the buffer tank is butted with the outlet of the supercritical natural gas supply system (2) via a flange; The second medium inlet (33) of the barrel of the static mixer, the jet mixer or the buffer tank is connected to the outlet of the dense phase carbon dioxide preparation system (1); The outlet end (32) of the cylinder of the static mixer, the jet mixer or the buffer tank is butted with the inlet of the mixed property detection system (4) via a flange; Wherein, the dense phase carbon dioxide preparation system (1) and the supercritical natural gas supply system (2) are used for preparing dense phase carbon dioxide fluid and supplying supercritical natural gas fluid respectively; The static mixer, the jet mixer and the buffer tank are used to mix the dense phase carbon dioxide fluid and the supplied supercritical natural gas fluid in the form of static mixing, jet mixing and buffer tank mixing respectively; The post-mixing property detection system (4) is used to detect the carbon dioxide content in the mixed fluid after mixing in different mixing forms and the pressure and temperature of the mixed fluid.

2. The device according to claim 1, characterized in that The dense phase carbon dioxide preparation system (1) comprises a carbon dioxide flange joint (10), a first pressure reducing valve (11), a first heating belt (12) and a first flow meter (13). The first heating belt (12) comprises a heating pipe, the heating pipe has an electric heating device built in, and the heating pipe is equipped with a first temperature control instrument (120). The carbon dioxide flange joint (10) is used for connecting to equipment storing high-pressure dense-phase carbon dioxide fluid; The carbon dioxide flange joint (10) is connected to the inlet of the heating pipeline of the first heating belt (12) via a first front pipeline; The outlet of the heating pipe of the first heating belt (12) is connected to the inlet of the first flow meter (13); The outlet of the first flow meter (13) is provided with a first rear pipe, and the outlet of the first rear pipe is used to connect with the second medium inlet (33) of the barrel of the static mixer, the jet mixer or the buffer tank; The first pressure reducing valve (11) is arranged on a first front pipe which is connected to the carbon dioxide flange joint (10) and the inlet of the heating pipe of the first heating belt (12).

3. The device according to claim 2, characterized in that A first check valve (14) is provided on a first rear pipeline connecting the outlet of the first flow meter (13) with the second medium inlet (33) of the barrel of the static mixer, the jet mixer or the buffer tank.

4. The device according to claim 3, characterized in that A first pressure gauge (15) is provided on the heating pipe of the first heating belt (12).

5. The device according to claim 1, characterized in that The supercritical natural gas supply system (2) comprises a compressed natural gas tank truck (20), a second pressure reducing valve (21), a second heating belt (22) and a second flow meter (23). The second heating belt (22) comprises a heating pipe, the heating pipe has an electric heating device built in, and the heating pipe is equipped with a second temperature control instrument (220). The compressed natural gas tank truck (20) stores high-pressure compressed natural gas in advance; The outlet of the compressed natural gas tank truck (20) is connected to the inlet of the heating pipeline of the second heating belt (22) via a second front pipeline; The outlet of the heating pipe of the second heating belt (22) is connected to the inlet of the second flow meter (23); The outlet of the second flow meter (23) is provided with a second rear pipe, and the outlet of the second rear pipe is used to connect with the second medium inlet (33) of the barrel of the static mixer, the jet mixer or the buffer tank; The second pressure reducing valve (21) is arranged on a second front pipeline of the compressed natural gas tank truck (20) connected to the inlet of the heating pipeline of the second heating belt (22).

6. The device according to claim 5, characterized in that A second check valve (24) is provided on a second rear pipeline connecting the outlet of the second flow meter (23) with the inlet end (31) of the cylinder of the static mixer, the jet mixer or the buffer tank.

7. The device according to claim 6, characterized in that A second pressure gauge (25) is provided on the heating pipe of the second heating belt (12).

8. The device according to claim 1, characterized in that The post-mixing property detection system (4) comprises a hollow pipe (41), a top carbon dioxide analyzer (421), a bottom carbon dioxide analyzer (422), an outlet pressure gauge (43) and a temperature sensor (44). The inlet end of the hollow pipe (41) is connected to the outlet end (32) of the barrel (30) of the static mixer, jet mixer or buffer tank of the blending and replacement system (3) through a flange; The top carbon dioxide analyzer (421) and the bottom carbon dioxide analyzer (422) are respectively arranged at the top and the bottom of the hollow pipe (41) near the outlet end of the hollow pipe (41); The outlet pressure gauge (43) and the temperature sensor (44) are respectively arranged at ports at the outlet end of the hollow pipe (41); The hollow pipe (41) is used to provide a mixed fluid after the dense phase carbon dioxide and the supercritical natural gas are mixed and further mixed and developed; The top carbon dioxide analyzer (421) and the bottom carbon dioxide analyzer (422) respectively collect the carbon dioxide content in the mixed fluid after the dense phase carbon dioxide and supercritical natural gas are mixed near the top and the bottom of the hollow pipe (41); The outlet pressure gauge (43) is used to collect the pressure of the mixed fluid at the outlet end of the hollow pipe (41); The temperature sensor (44) is used to collect the temperature of the mixed fluid at the outlet end of the hollow pipe (41).

9. The device according to claim 8, characterized in that The outlet end of the hollow pipe (41) is connected to a pneumatic valve (45), and the pneumatic valve (45) is provided with a discharge port.

10. A method for blending dense phase carbon dioxide and supercritical natural gas, using the device according to any one of claims 1 to 9, characterized in that: include: Step A: preparing dense phase carbon dioxide; Step B: supplying supercritical natural gas; Step C: The dense phase carbon dioxide is mixed with the supercritical natural gas to study the effects of different mixing forms on the properties of the dense phase carbon dioxide and supercritical natural gas after mixing.

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