Experimental device and method for gas replacement of crude oil pipeline

Abstract

The invention belongs to the technical field of crude oil storage tank leakage and disposal, and provides an experimental device and method for gas replacement of a crude oil pipeline, and the experimental device comprises a smoke generator and a model which are communicated with each other through a smoke delivery pipe; smoke generated by a smoke cake is input into the model to simulate oil gas, inert gas is filled through a gas inlet for replacement, in the replacement process, smoke concentration detection is conducted through smoke concentration monitors at different positions, the oil gas is replaced by smoke simulation, and in combination with the transparent model, the smoke concentration is detected. The change condition of a flow field in the replacement process under the leakage condition can be visually observed and understood, the problem of uncontrollable hidden dangers occurring after oil gas is discharged out of the pipeline does not exist, meanwhile, the multiple flue gas concentration monitors at different positions are combined, the condition that the oil gas concentration in each position in the pipeline is reduced under the oil gas leakage condition is further understood, and the oil gas leakage detection accuracy is improved. When leakage occurs in the crude oil pipeline for welding, the oil gas concentration change of each position in the replacement process can be determined, and safe data basis and the like are provided for welding.

Description

Technical Field

[0001] The invention belongs to the technical field of crude oil storage tank leakage and disposal, and particularly relates to an experimental device and method for gas replacement in a crude oil pipeline. Background Technique

[0002] As a common means of crude oil transportation, pipeline transportation is inevitably subject to corrosion, weld cracking, etc. during long-term operation. Once leakage occurs, it will cause resource loss, and may cause fire and explosion accidents when encountering an ignition source, seriously threatening property and personal safety.

[0003] Due to frequent occurrences of corrosion, oil theft by drilling holes, and leakage accidents in crude oil pipelines, the transportation cannot be completed normally, and serious accident consequences will occur when encountering an open flame. Therefore, pipeline repair is required. Among them, the welding process is affected by the oil and gas concentration and is extremely prone to explosion accidents. It is very necessary to study the process of oil and gas leakage in the crude oil pipeline and the reduction of the oil and gas concentration around the welding site through nitrogen replacement. Generally, most gas replacement experimental studies are carried out on scaled-down experimental models and simplified models, and the experimental methods are relatively mature.

[0004] However, current gas replacement experiments mostly involve the study of replacement laws and efficiencies, and cannot show the changes in the flow field during the replacement process, nor can they understand the decrease in the oil and gas concentration at each position in the pipeline under the condition of oil and gas leakage, and cannot provide a safe data basis for welding; moreover, during the oil and gas replacement process, the oil and gas are discharged from the pipeline, posing potential safety and uncontrollable hazards. Summary of the Invention

[0005] In order to solve the above problems, the invention provides an experimental device and method for gas replacement in a crude oil pipeline. The smoke generated by a smoke cake is input into the model to simulate oil and gas, and an inert gas is filled through the air inlet for replacement. During the replacement process, the smoke concentration is detected by smoke concentration monitors at different positions. By using smoke simulation instead of oil and gas and combining with a transparent model, the changes in the flow field during the replacement process under the condition of leakage can be visually observed and understood, and there is no uncontrollable hazard problem after the oil and gas are discharged from the pipeline; at the same time, in combination with multiple smoke concentration monitors at different positions, the decrease in the oil and gas concentration at each position in the pipeline under the condition of oil and gas leakage can be further understood, and when it is determined that leakage occurs in the crude oil pipeline and welding is required, the changes in the oil and gas concentration at each position during the replacement process can be determined, which can provide reference data such as safe working positions and replacement time required for welding.

[0006] To achieve the above object, in the first aspect, the invention provides an experimental device for gas replacement in a crude oil pipeline, and adopts the following technical solutions:

[0007] An experimental device for gas replacement in a crude oil pipeline includes a smoke generator and a model that are interconnected through a smoke delivery pipe;

[0008] The smoke generator includes a box body and a smoke cake disposed inside the box body; an air inlet, an air outlet, and a leakage port are formed on the model. The model is a transparent tube, and a concentration detection component is disposed inside the model. The concentration detection component includes a plurality of flue gas concentration monitors disposed at different positions inside the model.

[0009] Further, the box body is connected to the model by means of the flue gas delivery pipe; a blower is disposed inside the flue gas delivery pipe, and the blower is connected to a controller.

[0010] Further, a valve is disposed at a position between the blower and the model inside the flue gas delivery pipe.

[0011] Further, the flue gas generated by the smoke cake includes a light component of gas and a heavy component of solid particles.

[0012] Further, the model includes a pipe body, and an air inlet, an air outlet, and a leakage port are disposed on the pipe body.

[0013] Further, the leakage port is located directly above the pipe body, and the air inlet and the air outlet are respectively located on both sides of the leakage port; the model is a transparent acrylic pipe.

[0014] Further, the air inlet and the leakage port are connected to an air source system. The air source system is equipped with a pressure gauge and a flow meter for monitoring the pressure and flow rate of the gas. The air source system includes two parts that are independently or integrally arranged. One part is connected to the air inlet through a pipe and can send inert gas into the model according to a preset pressure and flow rate; the other part is connected to the leakage port through a pipe and can send gas into the model according to a preset pressure and flow rate, or extract gas from the model according to a preset pressure and flow rate.

[0015] Further, the air source system is connected to the controller, and the controller is configured to: adjust the actual control output power of the blower during the experiment and the actual gas supply pressure of the air source system during the experiment:

[0016]

[0017] Wherein, F is the actual control output power of the blower during the experiment; F 0 is the theoretical output power during the experiment; N is the real-time wind force detected during the experiment; N P is the preset wind force; T is the real-time temperature detected during the experiment; T 0 is the preset temperature; P is the actual gas supply pressure of the air source system during the experiment; p 0 is the theoretical gas supply pressure during the experiment; α, β, γ, and δ are all preset coefficients.

[0018] To achieve the above object, in a second aspect, the present invention further provides an experimental method for gas displacement of a crude oil pipeline, adopting the following technical solution:

[0019] An experimental method for gas displacement of a crude oil pipeline uses the experimental device for gas displacement of a crude oil pipeline as described in the first aspect, including: inputting the flue gas generated by a smoke cake into the model to simulate oil and gas, filling inert gas through the air inlet for displacement, and during the displacement process, detecting the flue gas concentration through the flue gas concentration detectors at different positions.

[0020] Furthermore, a support is provided under the model to ensure the model is placed horizontally; a leakage port is processed directly above the model, and an air inlet and an air outlet are processed on the left and right sides of the leakage port respectively; before the displacement experiment starts, the smoke cake burns completely in the box body, and after waiting for a preset time, when the readings monitored by the flue gas concentration detectors remain constant, the displacement experiment starts; at the same time, the air inlet and the air outlet are opened to start the displacement experiment, and the scene of the displacement gas is photographed and recorded.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The present invention includes a smoke generator and a model interconnected by a flue gas delivery pipe; the smoke generator includes a box body and a smoke cake arranged in the box body; the model is provided with an air inlet, an air outlet and a leakage port, the model is a transparent pipe, and a concentration detection component is arranged in the model, and the concentration detection component includes a plurality of flue gas concentration detectors arranged at different positions in the model; during the experiment, the flue gas generated by the smoke cake is input into the model to simulate oil and gas, inert gas is filled through the air inlet for displacement, and during the displacement process, the flue gas concentration is detected through the flue gas concentration detectors at different positions. By using flue gas simulation instead of oil and gas and combining with a transparent model, the change of the flow field during the displacement process under the leakage condition can be intuitively observed and understood, and there is no uncontrollable hidden danger problem that occurs after the oil and gas are discharged from the pipeline; at the same time, combined with a plurality of flue gas concentration detectors at different positions, the decrease of the oil and gas concentration at each position in the pipeline under the condition of oil and gas leakage can be further understood, and when it is determined that welding is required due to leakage in the crude oil pipeline, the change of the oil and gas concentration at each position during the displacement process can be obtained, which can provide reference data such as a safe working position for welding and the time required for displacement.

[0023] In the present invention, the flue gas generated by the combustion of smoke cakes is used to replace crude oil gas for experiments. On the one hand, the flue gas generated by the combustion of smoke cakes contains light components of gas and heavy components of solid particles, and its physical properties are similar to those of crude oil gas, so it can well replace crude oil gas. At the same time, the flue gas is grayish-white, which plays a role in visualizing gas replacement. In addition, directly using crude oil gas for gas replacement experiments has great potential safety hazards. Especially in a laboratory with general ventilation, using flue gas to replace it can well solve this problem, which has reference significance for experiments involving crude oil gas replacement or other experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings forming a part of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments and descriptions thereof of this embodiment are used to explain this embodiment and do not constitute an improper limitation of this embodiment.

[0025] Figure 1 It is a schematic structural diagram of the device according to Embodiment 1 of the present invention;

[0026] Figure 2 It is a schematic diagram of the leakage port position according to Embodiment 1 of the present invention;

[0027] Figure 3 It is a schematic diagram of the change in the solubility of the flue gas according to Embodiment 1 of the present invention;

[0028] Figure 4 It is a schematic diagram of the nitrogen replacement of the pipeline according to Embodiment 1 of the present invention;

[0029] Figure 5 It is the change in the flue gas concentration under different monitors according to Embodiment 1 of the present invention;

[0030] Among them, 1. Smoke generator; 101. Box body; 102. Smoke cake; 103. Flue gas delivery pipe; 104. Blower; 105. Controller; 106. Valve; 2. Model; 201. Pipe body; 202. Air inlet; 203. Air outlet; 204. Leakage port; 3. Support; 4. Concentration detection component. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0032] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further descriptions of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0033] Embodiment 1:

[0034] As Figure 1 and Figure 2As shown in the figure, this embodiment provides an experimental device for gas displacement of crude oil pipelines, including a smoke generator 1, a model 2, a support 3, and a concentration detection component 4. The experimental device also includes a gas source system, a camera, a smoke concentration alarm system, etc.

[0035] Optionally, the smoke generator 1 includes a box body 101, a smoke cake 102, a flue gas delivery pipe 103, a blower 104, a controller 105, a valve 106, etc.; the model 2 includes a pipe body 201, and an air inlet 202, an air outlet 203, and a leakage port 204 are provided on the pipe body 201.

[0036] The smoke cake 102 is placed into the box body 101, and the smoke cake 102 provides visual smoke for the experiment to simulate the leakage scenario. Both ends of the flue gas delivery pipe 103 are respectively connected to the box body 101 and the pipe body 201, and are used to transport the flue gas generated in the box body 101 into the pipe body 201. The blower 104 is arranged in the flue gas delivery pipe 103 to provide power for the flue gas transportation; the blower 104 is connected to the controller 105, and the controller 105 is used to control the power of the blower 104, so as to change the concentration of the transported flue gas. The valve 106 is arranged in the flue gas delivery pipe 103 and is used for the on / off of the flue gas delivery pipe 103.

[0037] The model 2 is used to simulate the leakage scenario; the gas source system provides inert gas for the displacement; the smoke concentration alarm system is used to judge the progress of the displacement. It can be understood that the air inlet 202 is connected to the gas source system through a pipeline.

[0038] In some embodiments, optionally, the model 2 is an acrylic pipe with a diameter D of 610 mm, a wall thickness of 5 mm, and a length of 1.5 m; a support 3 is provided under the model 2 to ensure that the pipeline model is placed horizontally. A leakage hole 204 is processed directly above the model 2, and an air inlet 202 and an air outlet 203 with a hole diameter of D40 mm are respectively processed 60 cm to the left and right of the leakage hole.

[0039] In some embodiments, the gas source system includes a common gas source and a gas source leakage system. The gas source system is equipped with a pressure gauge and a flow meter, which can be used to monitor the pressure and flow rate of the gas. It can be understood that the gas source system includes two parts that are independently or integrally arranged. Among them, one part is connected to the air inlet 202 through a pipeline and can send inert gases such as nitrogen into the model 2 according to a certain pressure and flow rate to displace the flue gas in the model 2; the other part can be connected to the leakage port 204 through a pipeline and can send gas into the model 2 according to a certain pressure and flow rate, or can also extract gas from the model 2 according to a certain pressure and flow rate to simulate the actual leakage situation.

[0040] In this embodiment, the flue gas generated by burning the smoke cake 102 is used to replace the crude oil gas, and the controller 105 is used to control the blower 104 to work at different powers, so as to achieve the purpose of controlling the flue gas concentration. Since directly using oil gas for experiments has potential safety and uncontrollability hazards, in this embodiment, the flue gas generated by the smoke cake 102 contains light components of gas and heavy components of solid particles, which is similar to the physical properties of crude oil gas. At the same time, the flue gas is grayish-white, which plays a role in visualizing the gas replacement.

[0041] In this embodiment, the flue gas generated by burning the experimental smoke cake is used to replace the crude oil gas for research, and air is used to replace nitrogen for gas replacement research. Among them, the flue gas is grayish-white, which plays a role in visualizing the research on the change distribution of oil gas concentration. The flue gas contains light components of gas and heavy components of solid particles, so the physical properties of the flue gas are similar to those of crude oil gas. The rate of the flue gas is controlled by a smoke generator and a blower. On this basis, experiments are carried out to study the nitrogen replacement process and law after the leakage of the crude oil pipeline. On the basis of the experimental research on nitrogen replacement, a pipeline model is designed according to the actual size of the crude oil pipeline on site for gas replacement experiments to explore the influence law of different replacement situations on gas replacement.

[0042] Optionally, the smoke concentration alarm system uses a smoke concentration detector, which can display the on-site real-time gas data of high-brightness LEDs, and can measure the smoke concentration data of 0-5000 ppm with a resolution of 1 ppm. The data measured by the smoke concentration detector is transmitted to the computer through 485 to USB conversion. The monitoring involves multiple detectors for data monitoring at the same time. Considering using a parallel setting of detectors to ensure that the detectors transmit data at the same time, the software uses configuration monitoring software, which can monitor the data of multiple detectors at the same time. The data is recorded every 1 s and the data change curve can be drawn in real time.

[0043] One of the working processes or principles of the experimental device in the present invention is:

[0044] S1. Build an experimental platform, including the model 2 and the flue gas delivery pipe 103, etc. A support 3 is provided under the model 2 to ensure that the model 2 is placed horizontally.

[0045] S2. Carry out processing and hole-opening operations on the model 2; optionally, a leakage port 204 is processed directly above the model 2, and an air inlet 202 and an air outlet 203 with a hole diameter of D40 mm are processed 60 cm to the left and right of the leakage port 204 respectively.

[0046] S3. Test the flue gas concentration monitor to ensure the accuracy of the test data and the timeliness of the transmitted data; the amount of the smoke cake used in each experiment is kept constant to ensure that the initial flue gas concentrations are similar.

[0047] S4. Before the replacement experiment starts, ensure that the smoke cake 102 burns completely in the box 101 (the concentration of the flue gas can be controlled by blowers 104 with different working powers). Wait for a period of time until the monitoring readings of the monitor remain constant, and then start the replacement experiment. At the same time, open the intake port 202 and the outlet port 203; when the replacement experiment starts, the scene of the replacement gas can be photographed and recorded using a high-definition pan-tilt camera. After the experiment starts, pay attention to the readings transmitted by the monitor and keep the injection rate constant at the injection end. When the monitor reading becomes 0, the replacement ends, and one replacement experiment is completed.

[0048] In some embodiments, optionally, before the replacement experiment starts, place the smoke cake 102 into the box 101. At the same time, open the valve 106 to ensure that the smoke cake 102 burns completely and use a low-speed variable-frequency fan to control the rate of the flue gas entering (the frequency opening is at the maximum at this time). Wait for a period of time until the monitoring readings of several flue gas concentration monitors remain constant, then close the valve 106 and start the replacement experiment. At the same time, open the intake port 202 and the outlet; when the replacement experiment starts, use a high-definition pan-tilt camera to photograph and record the scene of the replacement gas. After the experiment starts, pay attention to the readings transmitted by the monitor and keep the injection rate constant. For different replacement rates of 100 L / min, 200 L / min, 300 L / min, and 400 L / min, the frequency opening of the low-speed variable-frequency fan (blower) gradually increases. When the monitor reading becomes 0, the replacement ends. Different concentrations of smoke can be introduced to represent different gas-phase fraction crude oils to be replaced. For example, a gas-phase fraction of 0.8% corresponds to a smoke concentration of 800 ppm, and a gas-phase fraction of 0.3% corresponds to 300 ppm. After one replacement experiment is completed, the nitrogen replacement of the pipeline is shown in Figure 3 . Change the parameter conditions of the experiment, conduct the experiment in step S4, compare the replacement rules under different experimental conditions, and process and analyze the data. During the experiment, change different replacement conditions, record the flue gas concentration data at each monitoring point, and photograph the replacement form of the flue gas. Analyze the gas replacement situation of the crude oil pipeline through these data to explore the optimal replacement method.

[0049] Example 2:

[0050] This example uses the experimental equipment in Example 1 to further illustrate the replacement experiment. Specifically:

[0051] Explore the analysis of the gas replacement time law inside the pipeline: Taking the data obtained from the experimental condition of 0 liquid level and a replacement rate of 4 m / s as an example, use the designed experimental system to study the gas replacement time at different positions inside the pipeline space, and process the obtained data.

[0052] The data with the flue gas concentration in a stable state is taken as the initial 100% of the flue gas concentration, and the time when it starts to decline is taken as the initial time 0s of the flue gas decline. The data monitored by the monitors at different positions is plotted as Figure 4 shown below.

[0053] From Figure 4 it can be seen that the flue gas concentrations monitored by each monitor are all oscillating downward, but the times for each monitor to reach 0 (complete replacement) are different.

[0054] From Figure 4 it can be seen that monitors 3 and 5 return to 0 earlier because the air flow velocities at these two places are faster, driving the concentration to decline rapidly. From the data of other monitors, it can be seen that the time taken for the reading of monitor 4 to return to 0 is the longest. The monitor is located in the bottommost area of the longitudinal direction of the replacement outlet, where flue gas is likely to accumulate and it is not easy to complete the replacement completely. Therefore, more attention should be paid to the dead corners of the replacement during replacement, and the concentration change at any spatial point cannot be used as the basis for determining complete replacement.

[0055] According to the above experimental analysis, the horizontal monitoring data can be used as a reference for the basis of studying the replacement time law.

[0056] Example 3:

[0057] This example provides an experimental device for gas replacement of an oil pipeline. In the experimental device of this example, on the basis of including all the technical features of the experimental device in the example, the controller 105 is also connected to the gas source system to control the gas supply pressure and flow rate at the gas inlet 202, etc.

[0058] It can be understood that during the experiment, by controlling the power of the blower 104 through the controller 105, the flow characteristics such as the flow rate and pressure of the flue gas are made to match the actual oil and gas flow characteristics as much as possible to improve the matching of the experimental data with the actual data. However, in the actual environment, the pipeline is in different environments with different atmospheric pressures, and the atmospheric pressure has an impact on the entry and exit of inert gases; during the experiment, the gas inlet 202 is supplied with gas through the gas source system. Although the gas pressure setting refers to the ambient pressure, since the gas pressure supplied by the gas source system is relatively stable and does not consider the influence of wind force and temperature in the actual environment on the gas entering the pipeline, there is a large error between the experimental data and the actual situation. For example, when the wind force is large and blows horizontally across the gas inlet, it will affect the gas entering the pipeline.

[0059] Based on this, in this example, a wind sensor and a temperature sensor are set in the experimental environment to detect the wind force information and temperature information in the experimental environment; according to the wind force information and temperature information, the output power of the blower 104 and the gas supply pressure of the gas source system are finely adjusted or corrected to reduce the experimental error caused by wind force and temperature. Optionally:

[0060]

[0061] Among them, F is the actual control output power of the blower 104 during the experiment; F 0 is the theoretical output power during the experiment; N is the real-time wind force detected during the experiment; N P is the preset wind force; T is the real-time temperature detected during the experiment; T 0 is the preset temperature; P is the actual air supply pressure of the air source system during the experiment; P 0 is the theoretical air supply pressure during the experiment; α, β, γ, and δ are all preset coefficients and can be determined by means such as experiments.

[0062] In some embodiments, optionally, the influence of the external wind force and temperature on the output power of the blower 104 is less than that on the air source system. Based on this, α and β can be determined by comparing experimental data and actual data to reduce experimental errors. However, when the real-time wind force N detected during the experiment is equal to the preset wind force N P α is zero, and when the real-time temperature T detected during the experiment is equal to the preset temperature T P β is zero; when determining γ and δ, when the real-time wind force N detected during the experiment is greater than the preset wind force N P the pressure at the air inlet and outlet will become smaller. At this time, it is difficult to enter, but easy to discharge. It is necessary to reduce the air supply pressure of the air source system to make it more simulate the actual situation. At this time, γ is negative, otherwise, γ is positive. When the real-time wind force N detected during the experiment is equal to the preset wind force N P γ is zero; similarly, when the real-time temperature T detected during the experiment is less than the preset temperature T P the pressure at the air inlet and outlet will become smaller. At this time, it is difficult to enter, but easy to discharge. It is necessary to reduce the air supply pressure of the air source system to make it more simulate the actual situation. At this time, δ is negative, otherwise, δ is positive. When the real-time temperature T detected during the experiment is equal to the preset temperature T P δ is zero.

[0063] In this embodiment, the changes in environmental temperature, wind force, etc. during the experiment are considered. According to the real-time changes in temperature and wind force, the output power of the blower 104 and the air supply pressure of the air source system are adjusted in real time, making the experiment closer to the actual situation and reducing experimental errors.

[0064] Example 4:

[0065] This embodiment provides an experimental method for gas displacement of crude oil pipelines, using the experimental device for gas displacement of crude oil pipelines described in Embodiment 1 or Embodiment 3, including: inputting the flue gas generated by the smoke cake 102 into the model 2 to simulate oil and gas, filling inert gas through the air inlet 202 for displacement, and during the displacement process, detecting the flue gas concentration through flue gas concentration monitors at different positions.

[0066] Optionally, a support 3 is provided under the model 2 to ensure that the model 2 is placed horizontally; a leakage port 204 is machined directly above the model 2, and an air inlet 202 and an air outlet 203 are machined on the left and right sides of the leakage port 204 respectively; before the displacement experiment starts, the smoke cake 102 burns completely in the box body 101, and after waiting for a preset time, when the reading monitored by the flue gas concentration monitor remains constant, the displacement experiment starts; at the same time, the air inlet 202 and the air outlet 203 are opened to start the displacement experiment, and the scene of the displacement gas is photographed and recorded.

[0067] The above are only the preferred embodiments of this embodiment and are not used to limit this embodiment. For those skilled in the art, this embodiment can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this embodiment shall be included within the protection scope of this embodiment.

Claims

1. An experimental device for gas replacement in crude oil pipelines, characterized in that: It includes a smoke generator and a model which are interconnected by means of a smoke delivery pipe; The smoke generator includes a box body and a smoke cake arranged in the box body; the model is provided with an air inlet, an air outlet and a leakage port, the model is a transparent tube, a concentration detection component is arranged in the model, and the concentration detection component includes a plurality of smoke concentration monitors arranged at different positions in the model.

2. The experimental device for crude oil pipeline gas replacement according to claim 1, characterized in that: The box body is connected to the model by means of the smoke conveying pipe; a blower is arranged in the smoke conveying pipe, and the blower is connected to a controller.

3. The experimental device for gas replacement in crude oil pipeline according to claim 2, characterized in that: A valve is provided in the smoke conveying pipe at a position between the blower and the model.

4. The experimental device for gas replacement in a crude oil pipeline according to claim 1, characterized in that: The smoke generated by the smoke cake includes light components of gas and heavy components of solid particles.

5. The experimental device for gas replacement in crude oil pipeline according to claim 1, characterized in that: The model comprises a tube body, and an air inlet, an air outlet and a leakage port arranged on the tube body.

6. The experimental device for gas replacement in a crude oil pipeline as claimed in claim 5, characterized in that: The leakage port is located directly above the tube body, and the air inlet and the air outlet are respectively located on both sides of the leakage port; and the model is a transparent acrylic pipe.

7. The experimental device for gas replacement in a crude oil pipeline as claimed in claim 2, characterized in that: The air inlet and the leakage port are connected to an air source system, and the air source system is equipped with a pressure gauge and a flow meter for monitoring the pressure and flow of the gas; the air source system includes two parts that are independently or integrated, one part is connected to the air inlet through a pipeline, and can deliver the inert gas into the model at a preset pressure and flow; the other part is connected to the leakage port through a pipeline, and can deliver the gas into the model at a preset pressure and flow, or extract the gas from the model at a preset pressure and flow.

8. The experimental device for gas replacement in a crude oil pipeline as claimed in claim 7, characterized in that: The air source system is connected to the controller, and the controller is configured to adjust the actual control output power of the blower during the experiment and the actual air supply pressure of the air source system during the experiment: Among them, F is the actual control output power of the blower during the experiment; F0 is the theoretical output power during the experiment; N is the real-time wind force detected during the experiment; N P is the preset wind speed; T is the real-time temperature detected during the experiment; T0 is the preset temperature; P is the actual air supply pressure of the air source system during the experiment; P0 is the theoretical air supply pressure during the experiment; α, β, γ and δ are all preset coefficients.

9. An experimental method for gas displacement in a crude oil pipeline, characterized in that: An experimental device for crude oil pipeline gas replacement as described in any one of claims 1 to 8 is used, comprising: inputting smoke generated by smoke cakes into a model to simulate oil and gas, filling inert gas through an air inlet for replacement, and during the replacement process, detecting smoke concentration through smoke concentration monitors at different positions.

10. The experimental method for gas replacement in a crude oil pipeline according to claim 9, characterized in that: A support is provided under the model to ensure that the model is placed horizontally; a leakage port is processed directly above the model, and an air inlet and an air outlet are processed on the left and right sides of the leakage port respectively; before the replacement experiment starts, the smoke cake is completely burned in the box, and after waiting for a preset time, the replacement experiment begins after the smoke concentration monitor displays a constant reading; at the same time, the air inlet and air outlet are opened to start the replacement experiment, and the scene of the replaced gas is photographed and recorded.

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