CO2 gas-liquid mixed-phase pipeline conveying system and method

Abstract

The invention belongs to the technical field of CCUS pipeline transportation, and discloses a CO2 gas-liquid mixed-phase pipeline conveying system and method. The system comprises a liquid CO2 conveying subsystem, a gaseous CO2 conveying subsystem and a mixed-phase pressurized conveying subsystem, the liquid CO2 conveying subsystem comprises a liquid CO2 unloading skid, a liquid CO2 storage tank and a liquid feeding pump which are connected in sequence; the gaseous CO2 conveying subsystem comprises a gaseous CO2 in-station manifold, a compressor, a dehydration device and a filter which are connected in sequence; the mixed-phase pressurized conveying subsystem comprises a static mixer, a high-pressure reciprocating type mixed conveying pump, an outlet pressure stabilizer and a high-pressure pipeline which are connected in sequence; the liquid feeding pump is connected with a liquid phase inlet of the static mixer, and the filter is connected with a gas phase inlet of the static mixer. According to the invention, CO2 gas-liquid mixed-phase conveying can be efficiently realized, CO2 enters a conveying or injecting pipeline after being pressurized, the pressure reaches above supercritical pressure, and the method is short in process, low in energy consumption and high in efficiency and reliability.

Description

Technical Field

[0001] The present invention belongs to the technical field of CCUS pipeline transportation, and in particular relates to a CO2 gas-liquid mixed-phase pipeline transportation system and method. Background Art

[0002] CO2 pipeline transportation is divided into three transportation modes: gas phase transportation, liquid phase transportation, and supercritical state transportation. The gas phase transportation process is that high-concentration gaseous CO2 (generally 0.2MPa, concentration ≥95%, normal temperature) at low pressure or normal pressure is pressurized to a certain pressure (≤4.5MPa) by the pipeline booster station compressor and then enters the gas phase CO2 pipeline to the end of the pipeline. The pipeline does not need to be insulated. The liquid phase transportation process is that liquid CO2 (generally 2MPa, concentration ≥99%, -20℃) is pressurized to a certain pressure by the liquid CO2 pump of the booster station and then enters the liquid phase CO2 pipeline to the end of the pipeline. The pipeline needs to be kept cold. The supercritical state transportation process is that high-concentration gaseous CO2 (generally 0.2MPa, concentration ≥95%, normal temperature) at low pressure or normal pressure is pressurized to a certain pressure above the supercritical pressure (generally >9MPa) by the booster station compressor in multiple stages and then enters the supercritical CO2 pipeline to the end of the pipeline. The pipeline does not need to be insulated. The above three transportation methods all require that a single gas or liquid phase CO2 is pressurized by the booster equipment at the first station and then enters the pipeline. Currently, there is no method for CO2 gas-liquid mixed phase transportation.

[0003] At present, the gas-liquid mixed transmission pumps used in industrial applications include single-screw pumps and twin-screw pumps, but screw pumps have disadvantages such as small compression ratio, low discharge pressure, low efficiency, short life of seals and wearing parts, and poor reliability. Summary of the invention

[0004] The present invention aims to solve the technical problems existing in the prior art and provide a CO2 gas-liquid mixed phase pipeline transportation system and method, which can efficiently realize the CO2 gas-liquid mixed phase transportation, so that it enters the transportation pipeline or injection pipeline after being pressurized, and the pressure reaches above the supercritical pressure, and the process flow is short, the operating energy consumption is low, and the system efficiency and reliability are high.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] A CO2 gas-liquid mixed phase pipeline transportation system, comprising a liquid CO2 transportation subsystem, a gaseous CO2 transportation subsystem and a mixed phase pressurized transportation subsystem;

[0007] The liquid CO2 transport subsystem comprises a liquid CO2 unloading skid, a liquid CO2 storage tank and a liquid feeding pump which are connected in sequence;

[0008] The gaseous CO2 transport subsystem includes a gaseous CO2 inlet manifold, a compressor, a dehydration device and a filter connected in sequence;

[0009] The mixed-phase pressurized delivery subsystem includes a static mixer, a high-pressure reciprocating mixed delivery pump, an outlet pressure stabilizer and a high-pressure pipeline connected in sequence;

[0010] The liquid feeding pump is connected to the liquid phase inlet of the static mixer through a pipeline, and the filter is connected to the gas phase inlet of the static mixer through a pipeline.

[0011] Furthermore, a first flow meter, a first thermometer, a first pressure gauge and a first gate valve are provided on the connecting pipeline between the liquid feeding pump and the liquid phase inlet of the static mixer;

[0012] A second flow meter, a second thermometer, a second pressure gauge and a second gate valve are provided on the connecting pipe between the filter and the gas phase inlet of the static mixer;

[0013] A third thermometer and a third pressure gauge are provided on the pipeline between the static mixer and the high-pressure reciprocating mixing pump;

[0014] The outlet pressure stabilizer is provided with a fourth pressure gauge, and the outlet pipe of the outlet pressure stabilizer is provided with a fourth thermometer.

[0015] Furthermore, the first flowmeter is a mass flowmeter or a Venturi flowmeter; the second flowmeter is a swirl flowmeter or a Venturi flowmeter.

[0016] Furthermore, the second flow meter, the second thermometer, the second pressure gauge and the second gate valve are sequentially arranged on the connecting pipe between the filter and the gas phase inlet of the static mixer along the gas delivery direction;

[0017] The gaseous CO2 inlet manifold also includes a secondary gas outlet, and the secondary gas outlet is connected to the inlet pipe of the second flow meter through a bypass pipe; a third gate valve is arranged on the bypass pipe.

[0018] Furthermore, when the pressure and water content of the incoming gaseous CO2 meet the inlet requirements of the static mixer, the third gate valve is opened to allow the incoming gaseous CO2 to be directly mixed with liquid CO2 and enter the plunger-type mixing pump without pressurization and dehydration.

[0019] Further, it includes an instrument control system;

[0020] The instrument control system signals are connected to each flow meter, thermometer and pressure gauge to adjust the working parameters of each device in real time;

[0021] At the same time, the instrument control system is electrically connected to each gate valve to automatically control the on and off of each gate valve.

[0022] Furthermore, the inlet pressure of the compressor is the designed low-pressure inlet pressure of the CO2 pipeline booster station, and the outlet pressure is the designed output pressure of the dehydration device.

[0023] Furthermore, the compressor is a screw compressor or a reciprocating piston compressor.

[0024] Furthermore, the dehydration device is a molecular sieve dehydration device; and the filter is a dust filtering device.

[0025] Furthermore, the inlet pressure of the high-pressure reciprocating mixed-transfer pump is the liquid CO2 storage pressure, and the outlet pressure is the designed outlet pressure of the pipeline.

[0026] Furthermore, the high-pressure reciprocating mixed-flow pump is provided with over-temperature protection measures, specifically including:

[0027] Temperature sensors are provided on the compressed medium cavity and the transmission rod of the high-pressure reciprocating mixed flow pump, and a temperature monitoring circuit process is provided in the mixed flow pump control system of the high-pressure reciprocating mixed flow pump; the mixed flow pump control system receives the temperature data monitored by the temperature sensor and executes the following temperature protection measures:

[0028] When the temperature exceeds the rated working temperature, the mixed pump control system turns on an alarm to remind the operator to manually adjust the ratio of the liquid phase / gas phase of the mixed pump feed to meet the liquid holdup requirement of the high-pressure reciprocating mixed pump;

[0029] When the temperature exceeds the upper limit of the working temperature, the mixed flow pump control system forces the inlet valve of the high-pressure reciprocating mixed flow pump to be closed and the operation is suspended.

[0030] Furthermore, the high-pressure reciprocating mixed-flow pump is a plunger-type mixed-flow pump.

[0031] At the same time, the present invention also provides a CO2 gas-liquid mixed phase pipeline transportation method, which is implemented by using the system as described in any of the above items, and the method comprises the following steps:

[0032] When gaseous CO2 is input, the gaseous CO2 transport subsystem and the liquid CO2 transport subsystem are first opened, and the liquid CO2 flows into the liquid CO2 storage tank through the liquid CO2 unloading skid for storage. When there is sufficient liquid CO2 in the liquid CO2 storage tank, it enters the liquid feeding pump from the liquid CO2 storage tank for pressurization, and then enters the static mixer after metering;

[0033] At the same time, the gaseous CO2 is collected through the inlet manifold and then enters the compressor for pressurization. The pressurized gaseous CO2 enters the dehydration device to remove moisture, then enters the filter to filter out the dust impurities carried, and then enters the static mixer after metering;

[0034] After liquid CO2 and gaseous CO2 are fully mixed in the static mixer, they enter the high-pressure reciprocating mixing pump for pressurization. After pressurization, they enter the outlet pressure stabilizer to stabilize the pressure. When the pressure reaches the outlet pressure requirement, they enter the high-pressure pipeline for supercritical transportation.

[0035] Furthermore, the method further comprises the following steps:

[0036] When gaseous CO2 is input, if the pressure and water content of the inlet gaseous CO2 meet the inlet requirements of the high-pressure reciprocating mixed pump, that is, the pressure of the gaseous CO2 is equivalent to the storage pressure of the liquid CO2, and the water content meets the index requirements of the pipeline input, the gaseous CO2 will be directly metered after being collected at the gaseous CO2 inlet manifold and input into the static mixer. After the liquid CO2 and gaseous CO2 are fully mixed in the static mixer, they enter the high-pressure reciprocating mixed pump for pressurization, and finally enter the outlet pressure stabilizer to stabilize the pressure. When the pressure reaches the outlet pressure requirement, it enters the high-pressure pipeline for supercritical transportation.

[0037] Furthermore, the method further comprises the following steps:

[0038] When there is no gaseous CO2 input, the gaseous CO2 transport subsystem is closed and the liquid CO2 transport subsystem is opened, and the liquid CO2 flows into the liquid CO2 storage tank through the liquid CO2 unloading skid for storage; when there is sufficient liquid CO2 in the liquid CO2 storage tank, it enters the liquid feeding pump from the liquid CO2 storage tank for pressurization, and then enters the static mixer after metering; after flowing out of the static mixer, it enters the high-pressure reciprocating mixing pump for pressurization to above the supercritical pressure, and then enters the outlet pressure stabilizer to stabilize the pressure, and finally enters the high-pressure pipeline for supercritical transportation.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] (1) A high-pressure reciprocating mixed-transfer pump is a positive displacement pump that uses the reciprocating motion of a piston or a plunger in a pump cylinder to transport liquid. Compared with a screw pump, a high-pressure reciprocating mixed-transfer pump has the functions of both a pump and a compressor, has an internal compression function, is highly efficient and energy-saving, and can adapt to complex gas-liquid mixed-transfer conditions with high gas content and high compression ratio. The CO2 gas-liquid mixed-phase pipeline transportation system and method provided by the present invention mixes the transported liquid CO2 with the pressurized and dehydrated gaseous CO2 from the pipeline, and uses a plunger-type mixed-transfer pump to simultaneously pressurize the gaseous and liquid CO2 media to above the supercritical pressure and then enter the pipeline for transportation. Compared with the process of separately setting up a compressor and a screw pump to pressurize the gaseous and liquid CO2 to above the supercritical pressure and then mix them into the pipeline for transportation, the station process flow is greatly reduced and the number of equipment is reduced. Not only is the project investment lower, but the mixed-transfer pump has a shorter process flow, lower operating energy consumption, and higher system efficiency and reliability than the combined operation of a compressor + a screw pump.

[0041] (2) The CO2 gas-liquid mixed phase pipeline transportation system and method provided by the present invention applies a plunger-type mixed delivery pump to the field of CO2 pipeline transportation. Since the temperature of liquid CO2 is low, it is mixed with gaseous CO2 and then pressurized and transported by a plunger-type mixed delivery pump. Compared with using a compressor for pressurization, the outlet medium temperature will not be too high, thereby reducing the energy consumption of cooling equipment such as air coolers and significantly reducing operating costs;

[0042] (3) The CO2 gas-liquid mixed phase pipeline transportation system and method provided by the present invention can be applied to the first station of the carbon dioxide long-distance pipeline pressurization, or to the injection of carbon dioxide in oil fields, where the injection medium is purchased liquid carbon dioxide and produced gaseous carbon dioxide and needs to be pressurized at the same time. The process has significant economic benefits, strong practicality, and high application and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the structure of a CO2 gas-liquid mixed phase pipeline transportation system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In the description of the present invention, it is necessary to understand that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "front", "center", "both ends" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0046] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0047] Example 1

[0048] Combination Figure 1 As shown, an embodiment of the present invention provides a CO2 gas-liquid mixed phase pipeline transportation system, including a liquid CO2 unloading skid 1, a liquid CO2 storage tank 2, a liquid feeding pump 3, a gaseous CO2 inlet manifold 4, a compressor 5, a dehydration device 6, a filter 7, a static mixer 8, a plunger-type mixed delivery pump 9, an outlet pressure stabilizer 10, a high-pressure pipeline 11, a first gate valve 22, a second gate valve 33, a third gate valve 44, a first flow meter 101, a second flow meter 102, a first pressure gauge 201, a second pressure gauge 202, a third pressure gauge 203, a fourth pressure gauge 204, a first thermometer 301, a second thermometer 302, a third thermometer 303, and a fourth thermometer 304.

[0049] The liquid CO2 unloading skid 1 is connected to the inlet of the liquid CO2 storage tank 2 through a pipeline, the outlet of the liquid CO2 storage tank 2 is connected to the inlet of the liquid feeding pump 3 through a pipeline, the outlet of the liquid feeding pump 3 is connected to the liquid phase inlet of the static mixer 8 through a pipeline, the outlet of the gaseous CO2 inlet manifold 4 is connected to the inlet of the compressor 5 through a pipeline, the outlet of the compressor 5 is connected to the inlet of the dehydration device 6 through a pipeline, the outlet of the dehydration device 6 is connected to the inlet of the filter 7 through a pipeline, the outlet of the filter 7 is connected to the gas phase inlet of the static mixer 8 through a pipeline, the outlet of the static mixer 8 is connected to the inlet of the plunger type mixed flow pump 9 through a pipeline, the outlet of the plunger type mixed flow pump 9 is connected to the inlet of the outlet pressure regulator 10 through a pipeline, the outlet of the outlet pressure regulator 10 is connected to the inlet of the high-pressure pipeline 11 through a pipeline, and the secondary outlet of the gaseous CO2 inlet manifold 4 is connected to the gas phase inlet of the static mixer 8 through a pipeline.

[0050] The connecting pipeline between the liquid feeding pump 3 and the liquid phase inlet of the static mixer 8 is provided with a first flow meter 101, a first thermometer 301, a first pressure gauge 201 and a first gate valve 22 in sequence.

[0051] A second flow meter 102, a second thermometer 302, a second pressure gauge 202 and a second gate valve 33 are provided on the connecting pipe between the filter 7 and the gas phase inlet of the static mixer 8; the gaseous CO2 inlet manifold 4 also includes a secondary gas outlet, which is connected to the inlet pipe of the second flow meter 102 through a bypass pipe; and a third gate valve 44 is provided on the bypass pipe.

[0052] A third thermometer 303 and a third pressure gauge 203 are provided on the pipeline between the static mixer 8 and the high-pressure reciprocating mixing pump 9; a fourth pressure gauge 204 is connected to the outlet pressure regulator 10, and a fourth thermometer 304 is provided on the connecting pipeline between the outlet pressure regulator 10 and the high-pressure pipeline 11.

[0053] The first flow meter 101 is arranged on the pipeline between the liquid feeding pump 3 and the static mixer 8 to measure the amount of liquid CO2 entering the plunger type mixing pump 9;

[0054] The second flow meter 102 is arranged on the pipeline between the filter 7 and the static mixer 8, and is used to measure the amount of gaseous CO2 entering the plunger type mixing pump 9;

[0055] The first flowmeter 101 is a mass flowmeter, a Venturi flowmeter, etc.; the second flowmeter 102 is a swirl flowmeter, a Venturi flowmeter, etc.

[0056] The liquid feeding pump 3 is arranged on the pipeline between the liquid CO2 storage tank 2 and the liquid phase inlet of the static mixer 8, and the liquid feeding pump 3 is a shielded pump.

[0057] Compressor 5 can pressurize gaseous CO2. Compressor 5 is generally a screw or reciprocating piston compressor. The inlet pressure is the designed low-pressure inlet pressure of the CO2 pipeline booster station, and the outlet pressure is the designed output pressure of the dehydration device.

[0058] The dehydration device 6 is a molecular sieve dehydration device, which removes moisture from the gaseous CO2 entering the station, lowers the water dew point, and avoids corrosion of the back-end pipelines and equipment.

[0059] The filter 7 is a dust filtering device for removing dust carried in the gaseous CO2 passing through the molecular sieve dehydration device.

[0060] The inlet pressure of the plunger type mixed delivery pump 9 is the liquid CO2 storage pressure, and the outlet pressure is the designed outlet pressure of the pipeline.

[0061] The plunger-type mixed flow pump 9 cannot pressurize pure gaseous CO2 for a long time, otherwise it will cause the temperature to be too high and the equipment to be damaged. For this reason, the plunger-type mixed flow pump is provided with over-temperature protection measures, which specifically include:

[0062] Temperature sensors are provided on the compression medium cavity and the transmission rod of the plunger-type mixed-injection pump 9. A temperature monitoring circuit process is provided in the mixed-injection pump control system of the plunger-type mixed-injection pump 9. The mixed-injection pump control system receives the temperature data monitored by the temperature sensor and executes the following temperature protection measures:

[0063] When the temperature exceeds the rated working temperature of 130°C, the mixed pump control system turns on an alarm to remind the operator to manually adjust the ratio of the liquid phase / gas phase of the mixed pump feed to meet the liquid holdup requirement of the plunger mixed pump 9;

[0064] When the temperature exceeds the upper limit of the working temperature of 160° C., the mixed pump control system forces the inlet valve of the high-pressure reciprocating mixed pump to be closed and the operation is suspended.

[0065] After analysis, the main reason for the high temperature of the mixed pump is idling or insufficient liquid holdup of the mixed pump (different types of mixed pumps have different liquid holdup requirements). When the ratio of liquid phase / gas phase in the mixed pump feed exceeds a certain value, the compression heat will increase, and insufficient heat dissipation of the contact liquid phase and the equipment itself will cause the temperature of the equipment to rise. Therefore, when the temperature exceeds the operating temperature of the mixed pump, the ratio of liquid phase / gas phase must be strictly controlled to meet the liquid holdup requirements of the mixed pump.

[0066] When the temperature exceeds the upper limit of the working temperature, the inlet valve of the plunger type mixed delivery pump 9 is forcibly closed, and the operation is suspended. When the temperature returns to below the rated working temperature, it is restarted. If the shutdown time in the middle is long, the equipment container pipeline needs to be emptied and depressurized before restarting.

[0067] The power equipments such as the liquid feeding pump 3, the compressor 5 and the plunger type mixed delivery pump 9 are all driven by motors.

[0068] The CO2 gas-liquid mixed phase pipeline transportation system also includes an instrument control system; the instrument control system signals are connected to each flow meter, thermometer and pressure gauge for real-time adjustment of the working parameters of each device; at the same time, the instrument control system is electrically connected to each gate valve for automatically controlling the opening and closing of each gate valve.

[0069] Example 2

[0070] The embodiment of the present invention provides a CO2 gas-liquid mixed phase pipeline transportation method, which is implemented using the system in Example 1. The method includes the following steps:

[0071] When gaseous CO2 is input, first open the first gate valve 22 and the second gate valve 33, close the third gate valve 44, and the liquid CO2 flows from the tanker through the liquid CO2 unloading skid 1 into the liquid CO2 storage tank 2 in the station for storage. When it is ensured that there is sufficient liquid CO2 in the liquid CO2 storage tank 2, open the liquid feeding pump 3, and after being measured by the first flowmeter 101, input the liquid CO2 into the static mixer 8; at the same time, the low-pressure gaseous CO2 is collected through the station entry manifold 4 and enters the compressor 5 for pressurization. The pressurized gaseous CO2 enters the dehydration device 6 to remove most of the moisture, and then enters the filter 7 to filter the dust impurities carried, and then enters the static mixer 8 after being measured by the second flowmeter 102; after the liquid CO2 and the gaseous CO2 are fully mixed in the static mixer 8, they enter the plunger-type mixed delivery pump 9 for pressurization, and finally enter the outlet pressure stabilizer 10 to stabilize the pressure. When the pressure reaches the outlet pressure requirement, it enters the high-pressure pipeline 11 for supercritical transportation.

[0072] If the pressure and water content of the incoming gaseous CO2 meet the inlet requirements of the plunger-type mixed delivery pump 9, that is, the pressure of the gaseous CO2 is equivalent to the storage pressure of the liquid CO2, and the water content meets the index requirements of the pipeline input, then the third gate valve 44 is opened, and the inlet of the compressor 5 is closed, so that the gaseous CO2 is collected in the gaseous CO2 inlet manifold 4 and measured by the second flowmeter 102, and then input into the static mixer 8. After the liquid CO2 and the gaseous CO2 are fully mixed in the static mixer 8, they enter the plunger-type mixed delivery pump 9 for pressurization, and finally enter the outlet pressure stabilizer 10 to stabilize the pressure. When the pressure reaches the outlet pressure requirement, it enters the high-pressure pipeline 11 for supercritical transportation.

[0073] In addition, if there is no gaseous CO2 input, the second gate valve 33 is closed and the first gate valve 22 is opened, and the liquid CO2 flows from the tank truck through the liquid CO2 unloading skid 1 into the liquid CO2 storage tank 2 in the station for storage. When there is sufficient liquid CO2 in the liquid CO2 storage tank 2, it enters the liquid feeding pump 3 from the bottom outlet of the liquid CO2 storage tank 2 for pressurization, and then enters the static mixer 8 after being measured by the first flowmeter 101. After flowing out of the static mixer 8, it enters the plunger mixing pump 9 for pressurization to above the supercritical pressure, and then enters the outlet pressure stabilizer 10 to stabilize the pressure, and finally enters the high-pressure pipeline 11 for supercritical transportation.

[0074] The embodiment of the present invention mixes the transported liquid CO2 with the gaseous CO2 that has been pressurized and dehydrated from the pipeline, and uses a plunger-type mixed pump 9 to pressurize the gaseous and liquid CO2 media to above the supercritical pressure at the same time, and then enters the high-pressure pipeline 11 for transportation. Compared with the process of separately setting up a compressor and a pump to pressurize the gaseous and liquid CO2 to above the supercritical pressure and then mixing them into the pipeline for transportation, the station process flow is greatly shortened and the number of equipment is reduced. Not only is the project investment lower, but the mixed pump also has lower operating energy consumption than the combination of a compressor + a screw pump, and the system efficiency and reliability are higher.

[0075] The above description is only an embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the application scope of the present invention shall be included in the protection scope of the present invention.

Claims

1. A CO2 gas-liquid mixed phase pipeline transportation system, characterized in that: It includes a liquid CO2 transport subsystem, a gaseous CO2 transport subsystem and a mixed-phase pressurized transport subsystem; The liquid CO2 transport subsystem comprises a liquid CO2 unloading skid, a liquid CO2 storage tank and a liquid feeding pump which are connected in sequence; The gaseous CO2 transport subsystem includes a gaseous CO2 inlet manifold, a compressor, a dehydration device and a filter connected in sequence; The mixed-phase pressurized delivery subsystem includes a static mixer, a high-pressure reciprocating mixed delivery pump, an outlet pressure stabilizer and a high-pressure pipeline connected in sequence; The liquid feeding pump is connected to the liquid phase inlet of the static mixer through a pipeline, and the filter is connected to the gas phase inlet of the static mixer through a pipeline.

2. The system according to claim 1, characterized in that A first flow meter, a first thermometer, a first pressure gauge and a first gate valve are provided on the connecting pipeline between the liquid feeding pump and the liquid phase inlet of the static mixer; A second flow meter, a second thermometer, a second pressure gauge and a second gate valve are provided on the connecting pipe between the filter and the gas phase inlet of the static mixer; A third thermometer and a third pressure gauge are provided on the pipeline between the static mixer and the high-pressure reciprocating mixing pump; The outlet pressure stabilizer is provided with a fourth pressure gauge, and the outlet pipe of the outlet pressure stabilizer is provided with a fourth thermometer.

3. The system according to claim 2, characterized in that The first flow meter is a mass flow meter or a Venturi flow meter; the second flow meter is a swirl flow meter or a Venturi flow meter.

4. The system according to claim 2, characterized in that The second flow meter, the second thermometer, the second pressure gauge and the second gate valve are sequentially arranged on the connecting pipe between the filter and the gas phase inlet of the static mixer along the gas delivery direction; The gaseous CO2 inlet manifold also includes a secondary gas outlet, and the secondary gas outlet is connected to the inlet pipe of the second flow meter through a bypass pipe; a third gate valve is arranged on the bypass pipe.

5. The system according to claim 4, characterized in that When the pressure and water content of the incoming gaseous CO2 meet the inlet requirements of the static mixer, the third gate valve is opened to allow the incoming gaseous CO2 to be directly mixed with liquid CO2 and enter the plunger-type mixing pump without pressurization and dehydration.

6. The system according to claim 2, characterized in that Also includes instrument control systems; The instrument control system signals are connected to each flow meter, thermometer and pressure gauge to adjust the working parameters of each device in real time; At the same time, the instrument control system is electrically connected to each gate valve to automatically control the on and off of each gate valve.

7. The system according to claim 1, characterized in that The inlet pressure of the compressor is the designed low-pressure inlet pressure of the CO2 pipeline booster station, and the outlet pressure is the designed output pressure of the dehydration device.

8. The system according to claim 6, characterized in that The compressor is a screw compressor or a reciprocating piston compressor.

9. The system according to claim 1, characterized in that The dehydration device is a molecular sieve dehydration device; and the filter is a dust filtering device.

10. The system according to claim 1, characterized in that The inlet pressure of the high-pressure reciprocating mixed-transfer pump is the liquid CO2 storage pressure, and the outlet pressure is the designed outlet pressure of the pipeline.

11. The system according to claim 1, characterized in that The high-pressure reciprocating mixed-transfer pump is provided with over-temperature protection measures, specifically including: Temperature sensors are provided on the compressed medium cavity and the transmission rod of the high-pressure reciprocating mixed flow pump, and a temperature monitoring circuit process is provided in the mixed flow pump control system of the high-pressure reciprocating mixed flow pump; the mixed flow pump control system receives the temperature data monitored by the temperature sensor and executes the following temperature protection measures: When the temperature exceeds the rated working temperature, the mixed pump control system turns on an alarm to remind the operator to manually adjust the ratio of the liquid phase / gas phase of the mixed pump feed to meet the liquid holdup requirement of the high-pressure reciprocating mixed pump; When the temperature exceeds the upper limit of the working temperature, the mixed flow pump control system forces the inlet valve of the high-pressure reciprocating mixed flow pump to be closed and the operation is suspended.

12. The system according to any one of claims 1 to 11, characterized in that: The high-pressure reciprocating mixed-flow pump is a plunger-type mixed-flow pump.

13. A CO2 gas-liquid mixed phase pipeline transportation method, implemented by the system according to any one of claims 1 to 12, characterized in that: The method comprises the following steps: When gaseous CO2 is input, the gaseous CO2 transport subsystem and the liquid CO2 transport subsystem are first opened, and the liquid CO2 flows into the liquid CO2 storage tank through the liquid CO2 unloading skid for storage. When there is sufficient liquid CO2 in the liquid CO2 storage tank, it enters the liquid feeding pump from the liquid CO2 storage tank for pressurization, and then enters the static mixer after metering; At the same time, the gaseous CO2 is collected through the inlet manifold and then enters the compressor for pressurization. The pressurized gaseous CO2 enters the dehydration device to remove moisture, then enters the filter to filter out the dust impurities carried, and then enters the static mixer after metering; After liquid CO2 and gaseous CO2 are fully mixed in the static mixer, they enter the high-pressure reciprocating mixing pump for pressurization. After pressurization, they enter the outlet pressure stabilizer to stabilize the pressure. When the pressure reaches the outlet pressure requirement, they enter the high-pressure pipeline for supercritical transportation.

14. The method according to claim 13, characterized in that The following steps are also included: When gaseous CO2 is input, if the pressure and water content of the inlet gaseous CO2 meet the inlet requirements of the high-pressure reciprocating mixed pump, that is, the pressure of the gaseous CO2 is equivalent to the storage pressure of the liquid CO2, and the water content meets the index requirements of the pipeline input, the gaseous CO2 will be directly metered after being collected at the gaseous CO2 inlet manifold and input into the static mixer. After the liquid CO2 and gaseous CO2 are fully mixed in the static mixer, they enter the high-pressure reciprocating mixed pump for pressurization, and finally enter the outlet pressure stabilizer to stabilize the pressure. When the pressure reaches the outlet pressure requirement, it enters the high-pressure pipeline for supercritical transportation.

15. The method according to claim 13, characterized in that The following steps are also included: When there is no gaseous CO2 input, the gaseous CO2 transport subsystem is closed and the liquid CO2 transport subsystem is opened, and the liquid CO2 flows into the liquid CO2 storage tank through the liquid CO2 unloading skid for storage; when there is sufficient liquid CO2 in the liquid CO2 storage tank, it enters the liquid feeding pump from the liquid CO2 storage tank for pressurization, and then enters the static mixer after metering; after flowing out of the static mixer, it enters the high-pressure reciprocating mixing pump for pressurization to above the supercritical pressure, and then enters the outlet pressure stabilizer to stabilize the pressure, and finally enters the high-pressure pipeline for supercritical transportation.

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