Experimental apparatus and method for simulating internal corrosion and flow in a pipeline

Abstract

The application discloses an experimental device for simulating pipeline internal corrosion and flow, and a loop system is detachably connected by multiple pipeline units, and the loop system comprises a top simulation unit, a horizontal tube plate is arranged at the top of the pipeline of the top simulation unit, and the bottom surface of the horizontal tube plate serves as a working electrode; and two groups of inclined simulation units, one group of which is made of metal material, and the other group of which is made of transparent material, the two groups of inclined simulation units are alternatively connected in the loop system, and each group of the inclined simulation units comprises two inclined pipe sections, a horizontal pipe section and two first elbows which are connected with the end portions of the two inclined pipe sections, and the angle of the first elbow is between 0 and 90 degrees. The application further discloses an experimental method for simulating pipeline internal corrosion and flow. Through the two groups of inclined simulation units, the application can simulate the flow and corrosion in pipelines with different inclination angles; and through the horizontal tube plate of the top simulation unit, the application can simulate the top corrosion of large pipelines.

Description

Technical Field

[0001] This invention relates to the field of corrosion and protection technology for metal pipelines, and in particular to an experimental apparatus and method for simulating corrosion and flow inside pipelines. Background Technology

[0002] If a wet natural gas pipeline passes through mountainous areas, hilly terrain, crosses regions, or has significant elevation differences, the pipeline cannot be laid horizontally and typically has a certain angle of inclination. Therefore, the design of a simulated pipeline system is crucial for simulating the flow patterns and corrosion within such an inclined system using indoor simulation techniques.

[0003] In addition, long-distance oil and gas pipelines generally have large diameters, with the largest exceeding 1 meter. Due to their large diameter, the top of these pipelines, such as at the twelve o'clock position, is relatively flat. However, indoor simulated pipelines generally have smaller diameters and greater curvature at the top, making it difficult to simulate the corrosion behavior at the top of large pipelines using corrosion-resistant plates on the top of small-diameter pipes.

[0004] Patent document (application number: 201710319631.3) discloses an experimental apparatus for simulating internal corrosion of pipelines. It employs a double-layered experimental pipeline within a corrosion test chamber to simulate top corrosion, internal corrosion, and flow conditions within the pipeline. Firstly, this type of pipeline setup inevitably results in a small diameter, making it unsuitable for simulating large pipelines. Secondly, the sample is mounted on the inner pipeline; this mounting method allows liquid to accumulate at the edges, creating an edge effect between the sample mounting location and the pipeline body. This leads to a significant difference in corrosion between the edge and center of the sample, resulting in large errors in the experimental results.

[0005] Patent document (application number: 201921446279.0) discloses an on-site electrochemical testing device for large power plant pipeline materials. It uses the outer wall of the large power plant pipeline as the working electrode, establishes an external electrolytic reaction cell, and employs a three-electrode system electrochemical testing method to conduct on-site electrochemical performance testing of the pipeline material to understand its corrosion status. However, this method uses a simulated solution as the electrolyte, which is static. It does not actually perform corrosion electrochemical testing on the real solution inside the large pipeline, and therefore cannot realistically simulate the corrosion situation under flow conditions within the pipeline.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] One of the objectives of this invention is to provide an experimental apparatus and method for simulating corrosion and flow within pipelines, thereby addressing the problem that existing experimental apparatuses cannot simulate the corrosion behavior at the top of large pipelines.

[0008] Another objective of this invention is to provide an experimental apparatus and method for simulating corrosion and flow within pipelines, thereby enabling the simulation and experimentation of flow patterns and corrosion in indoor pipeline systems with different inclination angles.

[0009] One of the objectives of this invention is to provide an experimental apparatus and method for simulating corrosion and flow within pipelines, thereby improving experimental accuracy, enriching the types of experimental simulations, and providing experimental and theoretical support for actual production.

[0010] To achieve the above objectives, according to a first aspect of the present invention, an experimental apparatus for simulating corrosion and flow within a pipeline is provided. The apparatus includes a feeding unit and a loop system constituting a circulation path for the experimental medium. The loop system is detachably connected from multiple pipeline segments. The loop system includes: a top simulation unit with a horizontal tube sheet at the top of its pipeline, the bottom surface of which serves as a working electrode; and two sets of inclined simulation units, one set made of a metallic material and the other of a transparent material. The two sets of inclined simulation units are selectively connected to the loop system. Each set of inclined simulation units includes: two inclined pipe segments arranged parallel to each other; a horizontal pipe segment connected between the two inclined pipe segments to form a portal frame structure; and two first elbows connected to the ends of the two inclined pipe segments, the angle of which is between 0° and 90°.

[0011] Furthermore, in the above technical solution, the loop system also includes: a condensation simulation unit, whose pipeline is equipped with a water cooler, the water cooler includes a coolant storage tank and a coolant coil, and the bottom of the pipeline of the condensation simulation unit is equipped with a condensate sampling port.

[0012] Furthermore, in the above technical solution, the condensation simulation unit is a separate pipe section and / or is located outside the pipe of the top simulation unit.

[0013] Furthermore, in the above technical solution, the inner wall of the top of the pipe of the top simulation unit is provided with two channels, which are symmetrically distributed on both sides of the twelve o'clock direction. The upper surface of the horizontal tube sheet is provided with two protruding ridges. The channel and the protruding ridge match in shape, and the protruding ridge and the channel slide relative to each other, thereby removing or pushing the horizontal tube sheet in.

[0014] Furthermore, in the above technical solution, the inner wall of the pipe of the top simulation unit and the surface outside the bottom surface of the horizontal tube sheet are provided with an insulating layer.

[0015] Furthermore, in the above technical solution, an endoscope is installed at the bottom of the pipe of the top simulation unit, and the endoscope monitors the bottom surface of the horizontal tube sheet.

[0016] Furthermore, in the above technical solution, the two inclined pipe sections and the flat pipe section of each inclined simulation unit are connected by two second elbows.

[0017] Furthermore, in the above technical solution, the inclined simulation unit made of metal material is equipped with multiple corrosion probes, which are respectively set at the first bend and the second bend.

[0018] Furthermore, in the above technical solution, the radius of curvature of the first bend and the second bend is 6 times the radius of the pipeline in the loop system.

[0019] Furthermore, in the above technical solution, the transparent material is heat- and pressure-resistant; the transparent material is PC, quartz, or PAM material.

[0020] Furthermore, in the above technical solution, the feeding unit includes: a gas cylinder area for providing the gas required for the experiment; a pre-mixing tank for preparing the experimental solution; and a gas-liquid separator, whose first inlet is connected to the gas cylinder area, the second inlet is connected to the pre-mixing tank, and the third inlet is connected to the outlet of the loop system. The gas outlet and liquid outlet of the gas-liquid separator are respectively connected to the inlet of the loop system, and the gas outlet is higher than the third inlet.

[0021] According to a second aspect of the present invention, the present invention provides an experimental method for an experimental apparatus employing any one of the above-described technical solutions to simulate corrosion and flow within a pipeline. The experimental method includes: simulating top corrosion of a large pipeline using a top simulation unit and monitoring bottom corrosion of a horizontal tube sheet; simulating pipelines at different inclination angles using an inclined simulation unit made of metallic material and monitoring corrosion of the inclined simulation unit; and / or simulating pipelines at different inclination angles using an inclined simulation unit made of transparent material and monitoring the flow of the experimental medium within the inclined simulation unit.

[0022] Furthermore, the experimental method in the above technical solution also includes: performing correlation analysis on the corrosion monitoring results and flow monitoring results of the two sets of tilted simulation units.

[0023] Furthermore, the experimental method in the above technical solution also includes: simulating the corrosion of the moisture system through a separately set condensation simulation unit, and monitoring the corrosion at the top and bottom of the pipe of the condensation simulation unit.

[0024] Furthermore, the experimental method in the above technical solution also includes: setting up a condensation simulation unit outside the pipe of the top simulation unit to simulate the top corrosion of large pipes and the corrosion of the moisture system, monitoring the bottom corrosion of the horizontal tube sheet and the condensation droplets and liquid film, and performing correlation analysis.

[0025] Furthermore, in the above technical solution, a high-speed camera is used to monitor the flow of the experimental medium in the tilted simulation unit; a corrosion probe is used to monitor the corrosion of the tilted simulation unit.

[0026] Compared with the prior art, the present invention has one or more of the following beneficial effects:

[0027] 1. Two sets of tilting simulation units can simulate flow and corrosion within pipes at different inclination angles. The experimental inclination angle can be varied between 0° and 90° via a first bend of varying angles. Examples include truss regions, uphill regions, and downhill regions. One set of tilting simulation units is made of metallic material, and the other is made of transparent material. The metallic tilting simulation unit is primarily used to monitor corrosion within the pipe at different inclination angles. To avoid the influence of corrosion probes on the flow pattern within the pipe, the transparent tilting simulation unit is mainly used to observe the flow state within the pipe. High-speed cameras can be used to capture flow changes within the transparent tilting simulation unit, such as flow velocity and flow pattern. If the experimental medium contains solids, such as sand particles, the settling and distribution of sand particles within the pipe can also be monitored within the transparent tilting simulation unit. The results of corrosion and flow monitoring within the two sets of tilting simulation units allow for the construction of a model of the influence of pipe inclination angle on corrosion and flow within the pipe, as well as the inherent variational characteristics of the influence of flow on corrosion.

[0028] 2. The horizontal tube sheet of the top simulation unit can simulate corrosion at the top of the pipe. Horizontal tube sheets of different widths can simulate the corrosion behavior at the top of pipes of different diameters, which is particularly suitable for simulating the corrosion behavior at the top of large pipes.

[0029] 3. Using the bottom surface of the horizontal tube sheet as the working electrode, compared to a smaller electrode, increases the probability of capturing localized corrosion. It also facilitates the simulation of condensate film formation, aggregation, and movement at the top of the pipe, enabling online observation of the initiation and development of localized corrosion. Furthermore, it allows for offline observation and characterization of the horizontal tube sheet after the experiment. In addition, it allows for the establishment of a correlation between localized corrosion and condensate droplets and films within the pipe, providing more comprehensive and reliable support for actual production.

[0030] 4. The horizontal tube sheet is installed in the pipeline through the cooperation of channels and ridges, which makes it easy to disassemble and replace; the other surfaces of the horizontal tube sheet, except for the working surface, are equipped with an insulating layer to avoid contact with corrosive media and avoid galvanic corrosion.

[0031] 5. The condensation simulation unit can simulate corrosion in a humid system. It can be set up independently or in combination with the top simulation unit. It can also sample and analyze the condensate formed in the pipe through the sampling port at the bottom of the pipe, and calculate the condensation rate.

[0032] 6. The various pipe sections of the loop system are detachably connected, which facilitates the arrangement according to experimental needs and makes maintenance convenient.

[0033] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of an experimental apparatus for simulating corrosion and flow inside a pipeline according to an embodiment of the present invention.

[0035] Figure 2 This is a schematic diagram of the structure of a condensation simulation unit according to an embodiment of the present invention.

[0036] Figure 3 This is a schematic axial cross-sectional view of a top simulation unit according to an embodiment of the present invention, showing the channel at the top of the pipe.

[0037] Figure 4 This is a top view of a horizontal tube sheet of a top simulation unit according to an embodiment of the present invention, showing the raised ridges on the upper surface of the horizontal tube sheet.

[0038] Explanation of key figure labels:

[0039] 10-Condensation simulation unit, 11-Water cooler, 111-Coolant storage tank, 112-Coolant coil, 113-Coolant pump, 12-Condensate sampling port, 20-Inclined simulation unit, 21-Inclined pipe section, 22-Horizontal pipe section, 23-First elbow, 24-Second elbow, 30-Top simulation unit, 31-Horizontal tube sheet, 311-Protruding rib, 32-Channel, 40-Flange, 50-Corrosion probe, 61-Gas cylinder, 62-Pre-mixed Tank, 621-Deionized water generating device, 622-Experimental medium inlet, 623-Level gauge, 624-Agitator, 625-Vent pipe, 63-Gas-liquid separator, 631-First inlet, 632-Second inlet, 6321-Flow meter, 633-Third inlet, 634-Gas outlet, 635-Liquid outlet, 636-Drain outlet, 637-Exhaust pipe, 6371-Recovery device, 638-Drain pipe, 639 Vacuum pump. Detailed Implementation

[0040] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0041] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0042] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “up,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0043] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0044] like Figure 1 As shown, the experimental apparatus for simulating corrosion and flow within a pipeline according to a specific embodiment of the present invention includes a feeding unit and a loop system constituting a circulation path for the experimental medium. The loop system is composed of multiple pipeline segments detachably connected, for example, the pipeline segments can be connected via flanges 40. The loop system includes a top simulation unit 30, two sets of inclined simulation units 20, and a condensation simulation unit 10, which respectively simulate corrosion at the top of a large pipeline, corrosion and flow conditions in inclined pipe sections, and corrosion in a humid system.

[0045] Combination Figure 2As shown, in one or more exemplary embodiments of the present invention, the condensation simulation unit 10 is used to simulate the corrosion of a humid system, such as the corrosion of a humid natural gas pipeline system. A water cooler 11 is provided outside the pipe of the condensation simulation unit 10 for cooling. The water cooler 11 includes a coolant storage tank 111 and a coolant coil 112. The coolant in the coolant storage tank 111 is ethylene glycol, chilled water, or other refrigerable liquid. The coolant coil 112 is spirally wound around the outside of the pipe, closely adhering to the outer wall of the pipe. During the experiment, coolant is pumped into the coolant coil 112 by a coolant pump 113, and the external temperature of the pipe is simulated by controlling the coolant temperature. Due to the temperature difference between the inside and outside of the pipe, the corrosive medium flowing inside the pipe comes into contact with the low-temperature pipe and condenses inside the pipe, forming corrosive condensate droplets or a liquid film. The condensate droplets flow inside the pipe, and multiple small droplets converge to form large droplets, which flow along the pipe wall towards the bottom of the pipe under the action of gravity, forming a corrosive liquid at the bottom of the pipe. Multiple corrosion probes 50 can be installed in the pipe of the condensation simulation unit 10 to monitor corrosion at the top and bottom of the pipe. The corrosion probe 50 can be a weightlessness probe, electrochemical probe, or resistance probe, etc., and the present invention is not limited thereto. The bottom of the pipe in the condensation simulation unit 10 can be equipped with a condensate sampling port 12 to sample, observe, and analyze the condensate formed in the pipe, and calculate the condensation rate. The condensation rate can be adjusted by the power of the coolant pump 113. Figure 1 The condensation simulation unit 10 is a separate pipe section. In one or more exemplary embodiments of the present invention, the condensation simulation unit may also be located outside the pipe of the top simulation unit 30, but the present invention is not limited thereto.

[0046] Combination Figure 3 and Figure 4As shown, in one or more embodiments of the present invention, a horizontal tube plate 31 is provided at the top of the pipe inside the top simulation unit 30, and the bottom surface of the horizontal tube plate 31 serves as a working electrode. This is mainly used to simulate the top corrosion of large pipes using small-diameter pipes. Further, in one or more exemplary embodiments of the present invention, two channels 32 are provided on the inner wall of the top of the pipe of the top simulation unit 30, symmetrically distributed on both sides at the twelve o'clock position. Two protruding ribs 311 are provided on the upper surface of the horizontal tube plate 31, and the channels 32 and protruding ribs 311 are matched in shape. The protruding ribs 311 slide relative to the channels 32, thereby allowing the horizontal tube plate 31 to be removed or pushed into the pipe. Further, in one or more exemplary embodiments of the present invention, an insulating layer (not shown in the figure) is provided on the inner wall of the pipe of the top simulation unit 30 and the surface outside the bottom surface of the horizontal tube plate 31 to avoid galvanic corrosion. Since top corrosion is usually related to the condensation of liquid inside the pipe, the temperature of the pipe wall is generally lower than the temperature inside the pipe, such as at the point where the insulation layer outside the pipe is damaged, or in the transition area between submarine pipes, buried pipes, and surface pipes, where there is a temperature difference area between the inside and outside of the pipe. For example, a condensation simulation unit can be added outside the top simulation unit 30. Further, in one or more exemplary embodiments of the present invention, an endoscope (not shown in the figure) can be provided at the bottom of the pipe of the top simulation unit 30. The endoscope monitors the bottom surface of the horizontal tube sheet 31, observing the condensation and migration of condensate droplets or liquid films on the bottom surface of the horizontal tube sheet 31, and the correlation between the location of localized corrosion and the location of the droplets or liquid films. After the experiment, the distribution of localized corrosion on the horizontal tube sheet 31 can be observed, or the depth and morphology of localized corrosion can be observed on the entire surface using a three-dimensional profilometer, establishing the correlation between localized corrosion and the condensate droplets or liquid films inside the pipe.

[0047] Furthermore, in one or more exemplary embodiments of the present invention, two sets of tilt simulation units 20, one set made of metal and the other made of transparent material, are selectively connected in the loop system. The tilt simulation units are mainly used to simulate flow and corrosion in pipes with different inclination angles, such as truss regions, uphill regions, and downhill regions. Each set of tilt simulation units 20 includes: two parallel tilted pipe sections 21, and a flat pipe section 22 connecting the two tilted pipe sections 21, forming a portal frame structure. The ends of the two tilted pipe sections 21 are connected to the loop system via two first elbows 23, the angle of which is between 0 and 90°, thereby simulating different inclination angles of the tilted pipe sections through the first elbows 23 at different angles. One of the two tilted pipe sections 21 can simulate an upward tilt angle, and the other can simulate a downward tilt angle. For example,... Figure 1As shown, the flow from the condensation simulation unit 10 to the inclined simulation unit 20 is at an upward angle, simulating an uphill slope, and the flow from the inclined simulation unit 20 to the top simulation unit 30 is at a downward angle, simulating a downhill slope. This invention is not limited to this. Exemplarily, the inclined pipe section 21 and the flat pipe section 22 are connected by a second elbow 24. Further, in one or more exemplary embodiments of this invention, the inclined simulation unit made of metallic material may be equipped with multiple corrosion probes 50, which are respectively disposed at the first elbow 23 and the second elbow 24 to monitor the corrosion at the elbow locations. This invention is not limited to this. Further, in one or more exemplary embodiments of this invention, the radius of curvature of the first elbow 23 and the second elbow 24 is 6 times the radius of the pipe in the loop system to approximate the actual field conditions as closely as possible. Further, in one or more exemplary embodiments of this invention, a temperature- and pressure-resistant transparent material is used to facilitate observation of the flow state inside the pipe. Exemplarily, the transparent material may be PC, quartz, or PAM material. To avoid the influence of corrosion probes installed inside the pipe on the flow pattern, the tilted simulation unit made of transparent material does not have corrosion probes installed. It is primarily used to observe the flow state within the pipe, and the experiment is conducted using a high-speed camera. The flow state can include flow velocity and flow pattern. When the experimental medium contains solid particles, the flow state also includes the settling and distribution of particles within the pipe, etc., but this invention is not limited to these limitations. The corrosion monitoring results from the tilted simulation unit of metallic materials and the flow monitoring results from the tilted simulation unit of transparent materials can be correlated for analysis, such as how flow and flow pattern affect the corrosion rate.

[0048] Furthermore, in one or more exemplary embodiments of the present invention, the feeding unit may include a gas cylinder area, a pre-mixing tank 62, and a gas-liquid separator 63. The gas cylinder area is equipped with gas cylinders 61 for the gases required for the experiment. If multiple gas environments exist in the experiment, the multiple gas pipelines are combined into one gas pipeline, ultimately entering from the first inlet 631 at the top of the gas-liquid separator 63 and extending to the bottom of the gas-liquid separator 63 to agitate the experimental solution. The pre-mixing tank 62 is used to prepare the experimental solution according to experimental needs. Deionized water generated by the deionized water generator 621 enters the pre-mixing tank 62. The solids or liquids required for the experiment are added to the pre-mixing tank 62 through the experimental medium inlet 622. The volume of the experimental solution is measured by a level gauge 623, and a stirrer 624 agitates the experimental solution. To eliminate the corrosive effect of oxygen in the experimental solution, nitrogen or other gases required for the experiment are introduced into the experimental solution through a vent pipe 625. The bottom end of the vent pipe 625 is located within the experimental solution, and the venting process also agitates the experimental solution. The experimental medium inlet 622 also serves as a gas outlet. The experimental medium enters the gas-liquid separator 63 through a liquid pump via the second inlet 632 at the top. A flow meter 6321 at the second inlet 632 measures the volume of the experimental solution pumped into the gas-liquid separator 63 and compares this volume with the liquid level gauge 623, thus providing double verification of the volume of the experimental solution entering the gas-liquid separator 63. The vent pipe 638 at the top of the gas-liquid separator 63 is connected to a vacuum pump 639. Before the experiment, the vacuum pump 639 evacuates the gas-liquid separator 63 and the loop system to ensure the oxygen content in the entire system reaches a certain concentration, reducing the corrosive effect of oxygen. The bottom of the gas-liquid separator 63 has a drain port 636, allowing for sampling and analysis of the experimental solution before the experiment, such as measuring the pH value and adjusting the pH as needed. The gas outlet 634 and liquid outlet 635 of the gas-liquid separator are connected to the inlet of the loop system, respectively, allowing the gas and liquid to mix and enter the loop system. The outlet of the loop system is connected to the third inlet 633 of the gas-liquid separator 63. Exemplarily, the region after gas-liquid mixing is the flow development zone, the length of which is more than 700 times the pipe diameter. The experimental medium is circulated back to the third inlet 633 of the gas-liquid separator 63 by the loop system. The liquid settles to the bottom of the gas-liquid separator 63 under gravity. The gas outlet 634 is higher than the third inlet 633, so only moisture is present at the gas outlet 634 during the experiment. Exemplarily, in order to maintain the temperature stability of the entire loop system during the experiment, the entire pipeline system needs to be covered, such as with insulating cotton. This invention is not limited to this. After the experiment, the experimental gas enters the recovery device 6371 through the exhaust pipe 637. The recovery device 6371 can be an alkaline absorption device, where the alkaline solution reacts with H2S and CO2 in the experimental gas to achieve the purpose of removal; the recovery device 6371 can also be an oxygen combustion device, which burns toxic gases such as H2S in the experimental gas into SO2 and other substances before discharge.

[0049] An experimental method for simulating corrosion and flow within a pipeline according to one or more embodiments of the present invention includes: simulating top corrosion of a large pipeline using a top simulation unit and monitoring bottom corrosion of a horizontal tube sheet; simulating pipelines at different inclination angles using an inclined simulation unit made of metallic material and monitoring corrosion of the inclined simulation unit; and / or simulating pipelines at different inclination angles using an inclined simulation unit made of transparent material and monitoring the flow of the experimental medium within the inclined simulation unit.

[0050] Furthermore, in one or more exemplary embodiments of the present invention, the experimental method further includes: performing correlation analysis on the corrosion monitoring results and flow monitoring results of the two sets of tilted simulation units.

[0051] Furthermore, in one or more exemplary embodiments of the present invention, the experimental method further includes: simulating corrosion of a moisture system using a separately configured condensation simulation unit, and monitoring corrosion at the top and bottom of the pipes of the condensation simulation unit.

[0052] Furthermore, in one or more exemplary embodiments of the present invention, the experimental method further includes: simulating the top corrosion of large pipelines and the corrosion of the moisture system by setting a condensation simulation unit outside the pipe of the top simulation unit, monitoring the bottom corrosion of the horizontal tube sheet and the condensation droplets and liquid film, and performing correlation analysis.

[0053] Furthermore, in one or more exemplary embodiments of the present invention, a high-speed camera is used to monitor the flow of the experimental medium within the tilted simulation unit; a corrosion probe is used to monitor the corrosion of the tilted simulation unit.

[0054] The experimental apparatus and method for simulating corrosion and flow in pipelines according to the present invention will be described in more detail below by way of specific embodiments. It should be understood that the present invention is not limited thereto.

[0055] Example 1

[0056] This embodiment simulates corrosion at different tilt angles. The angle of the first bend 23 is selected according to the experimental tilt angle requirements. A flange connection is used to install the tilt simulation unit 20 made of metal material, and a corrosion probe is installed.

[0057] Prepare the experimental solution in the pre-mixing tank 62. Depending on the experimental requirements, introduce gas, such as N2 or CO2, into the experimental solution to expel oxygen. If it is necessary to determine whether the experimental solution meets the experimental requirements, sample and analyze it through the drain port 636 at the bottom of the gas-liquid separator 63, such as measuring the pH value. Adjust the pH value of the experimental solution as needed.

[0058] Vacuum pump 639 is turned on to evacuate the experimental piping system and gas-liquid separator 63. The extracted air is discharged through vent pipe 17 until the oxygen content of the entire system reaches a certain value, such as 20 ppb. Experimental solution is pumped into gas-liquid separator 63, and flow meter 6321 measures the volume of experimental solution entering gas-liquid separator 63. The required experimental gas is then introduced into the experimental solution in gas-liquid separator 63, while the experimental solution is heated. Gas introduction is stopped once the required experimental pressure is reached.

[0059] The experimental solution is then introduced into the subsequent loop system to monitor the corrosion of the tilted simulation unit.

[0060] After the required experimental time has elapsed, stop supplying air and liquid to the loop system and remove the corrosion probe from the tilted simulation unit. Open the drain port 636 and the exhaust pipe 637, and activate the recovery device 6371. Purge the experimental system with nitrogen (N2).

[0061] Example 2

[0062] This embodiment simulates flow patterns at different tilt angles. The angle of the first bend 23 is selected according to the experimental tilt angle requirements, and a tilt simulation unit 20 made of transparent material is installed using a flange connection. A high-speed camera is installed on the transparent material tilt simulation unit for monitoring.

[0063] Prepare the experimental solution in the pre-mixing tank 62. Depending on the experimental requirements, introduce gas, such as N2 or CO2, into the experimental solution to expel oxygen. If it is necessary to determine whether the experimental solution meets the experimental requirements, sample and analyze it through the drain port 636 at the bottom of the gas-liquid separator 63, such as measuring the pH value. Adjust the pH value of the experimental solution as needed.

[0064] Vacuum pump 639 is turned on to evacuate the experimental piping system and gas-liquid separator 63. The extracted air is discharged through vent pipe 17 until the oxygen content of the entire system reaches a certain value, such as 20 ppb. Experimental solution is pumped into gas-liquid separator 63, and flow meter 6321 measures the volume of experimental solution entering gas-liquid separator 63. The required experimental gas is then introduced into the experimental solution in gas-liquid separator 63, while the experimental solution is heated. Gas introduction is stopped once the required experimental pressure is reached.

[0065] The experimental solution is then introduced into the subsequent loop system, and the flow state inside the pipe is captured by a high-speed camera.

[0066] After the required experimental time has elapsed, stop supplying air and liquid to the loop system. Open the drain port 636 and the exhaust pipe 637, and activate the recovery device 6371. Purge the experimental system with N2.

[0067] Example 3

[0068] This embodiment correlates the results of Embodiment 1 and Embodiment 2 to understand the flow and corrosion conditions inside the pipeline under different inclination angles.

[0069] Example 4

[0070] This embodiment simulates corrosion in a humid system. Two corrosion probes are installed at the top and bottom of the pipes in the condensation simulation unit 10.

[0071] Prepare the experimental solution in the pre-mixing tank 62. Depending on the experimental requirements, introduce gas, such as N2 or CO2, into the experimental solution to expel oxygen. If it is necessary to determine whether the experimental solution meets the experimental requirements, sample and analyze it through the drain port 636 at the bottom of the gas-liquid separator 63, such as measuring the pH value. Adjust the pH value of the experimental solution as needed.

[0072] Vacuum pump 639 is turned on to evacuate the experimental piping system and gas-liquid separator 63. The extracted air is discharged through vent pipe 17 until the oxygen content of the entire system reaches a certain value, such as 20 ppb. Experimental solution is pumped into gas-liquid separator 63, and flow meter 6321 measures the volume of experimental solution entering gas-liquid separator 63. The required experimental gas is then introduced into the experimental solution in gas-liquid separator 63, while the experimental solution is heated. Gas introduction is stopped once the required experimental pressure is reached.

[0073] This allows the experimental solution to enter the subsequent experimental loop system.

[0074] During the experiment, coolant pump 113 was turned on, pumping coolant into coolant coil 112. The coolant temperature was controlled to simulate the external temperature of the pipe. Due to the temperature difference between the inside and outside of the pipe, the corrosive medium flowing in the corrosive pipe section came into contact with the low-temperature pipe and condensed inside, forming corrosive condensate droplets or a liquid film. The upper corrosion probe was used to monitor corrosion at the top of the pipe. The condensate droplets flowed inside the pipe, with multiple small droplets converging to form larger droplets. Under the influence of gravity, these droplets flowed along the pipe wall towards the bottom, forming a corrosive liquid at the bottom. The lower corrosion probe was used to monitor corrosion at the bottom of the pipe. The condensate sampling port 12 was opened to sample and analyze the condensate formed in the pipe section, calculating the condensation rate. The condensation rate was adjusted by the power of coolant pump 113.

[0075] After the required experimental time has elapsed, stop supplying air and liquid to the loop system and remove the corrosion probe. Open the drain port 636 and the exhaust pipe 637, and activate the recovery device 6371. Purge the experimental system with nitrogen (N2).

[0076] Example 5

[0077] This embodiment simulates top corrosion of a large pipeline. The horizontal tube sheet 31 of the top simulation unit 20, except for the bottom surface, is isolated from the corrosive medium by using insulating adhesive or spraying. The horizontal tube sheet 31 is pushed into the internal channel 32 of the pipeline along the ridge 311, and the pipeline of the top simulation unit 20 is installed in a flanged loop system.

[0078] Prepare the experimental solution in the pre-mixing tank 62. Depending on the experimental requirements, introduce gas, such as N2 or CO2, into the experimental solution to expel oxygen. If it is necessary to determine whether the experimental solution meets the experimental requirements, sample and analyze it through the drain port 636 at the bottom of the gas-liquid separator 63, such as measuring the pH value. Adjust the pH value of the experimental solution as needed.

[0079] Vacuum pump 639 is turned on to evacuate the experimental piping system and gas-liquid separator 63. The extracted air is discharged through vent pipe 17 until the oxygen content of the entire system reaches a certain value, such as 20 ppb. Experimental solution is pumped into gas-liquid separator 63, and flow meter 6321 measures the volume of experimental solution entering gas-liquid separator 63. The required experimental gas is then introduced into the experimental solution in gas-liquid separator 63, while the experimental solution is heated. Gas introduction is stopped once the required experimental pressure is reached.

[0080] The experimental solution is then introduced into the subsequent loop system to monitor the corrosion of the top simulation unit. If it is necessary to observe the condensation and migration of condensate droplets or liquid films on the bottom surface of the horizontal tube sheet 31, as well as the correlation between the location of localized corrosion and the location of droplets or liquid films, an endoscope can be installed at the bottom opening of the top simulation unit for observation.

[0081] After the required experimental time has elapsed, stop supplying air and liquid to the loop system and remove the corrosion probe. Open the drain port 636 and the exhaust pipe 637, and activate the recovery device 6371. Purge the experimental system with nitrogen (N2).

[0082] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. An experimental apparatus for simulating corrosion and flow within a pipeline, comprising a feeding unit and a loop system constituting a circulation path for the experimental medium, characterized in that, The loop system is composed of multiple detachably connected pipe units, and the loop system includes: A top simulation unit, wherein a horizontal tube sheet is installed at the top of its pipe, and the bottom surface of the horizontal tube sheet serves as the working electrode; and Two sets of tilt simulation units, one set made of metallic material and the other made of transparent material, are selectively connected to the loop system. Each set of tilt simulation units includes: Two inclined pipe sections are arranged parallel to each other; A horizontal pipe section, which connects between the two inclined pipe sections to form a portal frame structure; and Two first elbows are connected to the ends of the two inclined pipe sections, and the angle of the first elbows is between 0 and 90°. The condensation simulation unit has a water cooler installed outside its pipes. The water cooler includes a coolant storage tank and a coolant coil. A condensate sampling port is provided at the bottom of the pipes of the condensation simulation unit. The condensation simulation unit is located outside the pipes of the top simulation unit. By setting the condensation simulation unit outside the pipes of the top simulation unit, the top corrosion of large pipelines and the corrosion of the moisture system are simulated, and the bottom corrosion of the horizontal tube sheet and the condensation droplets and liquid film are monitored and correlated.

2. The experimental apparatus for simulating corrosion and flow inside a pipeline according to claim 1, characterized in that, The condensation simulation unit is a separate pipe section.

3. The experimental apparatus for simulating corrosion and flow inside a pipeline according to claim 1, characterized in that, The inner wall of the top of the pipe in the top simulation unit is provided with two channels, which are symmetrically distributed on both sides of the twelve o'clock direction. The upper surface of the horizontal tube sheet is provided with two protruding ridges. The channel and the protruding ridge match the shape. The protruding ridge and the channel slide relative to each other, thereby removing or pushing the horizontal tube sheet in.

4. The experimental apparatus for simulating corrosion and flow inside a pipeline according to claim 1, characterized in that, The inner wall of the pipe in the top simulation unit and the surface outside the bottom of the horizontal tube sheet are provided with an insulating layer.

5. The experimental apparatus for simulating corrosion and flow inside a pipeline according to claim 1, characterized in that, An endoscope is installed at the bottom of the pipe in the top simulation unit, and the endoscope monitors the bottom surface of the horizontal tube sheet.

6. The experimental apparatus for simulating corrosion and flow inside a pipeline according to claim 1, characterized in that, The two inclined pipe sections of each set of inclined simulation units are connected to the flat pipe section through two second elbows.

7. The experimental apparatus for simulating corrosion and flow inside a pipeline according to claim 6, characterized in that, The inclined simulation unit, made of metallic material, is equipped with multiple corrosion probes, which are respectively located at the first bend and the second bend.

8. The experimental apparatus for simulating corrosion and flow inside a pipeline according to claim 6, characterized in that, The radii of curvature of the first elbow and the second elbow are 6 times the radius of the pipe in the loop system.

9. The experimental apparatus for simulating corrosion and flow inside a pipeline according to claim 1, characterized in that, The transparent material is heat- and pressure-resistant; the transparent material is PC, quartz, or PAM material.

10. The experimental apparatus for simulating corrosion and flow inside a pipeline according to claim 1, characterized in that, The feeding unit includes: The gas cylinder area is used to supply the gases required for experiments; Pre-mixing containers, used for preparing experimental solutions; and The gas-liquid separator has a first inlet connected to the gas cylinder area, a second inlet connected to the pre-mixing tank, and a third inlet connected to the outlet of the loop system. The gas outlet and liquid outlet of the gas-liquid separator are respectively connected to the inlet of the loop system, and the gas outlet is higher than the third inlet.

11. An experimental method using the experimental apparatus for simulating corrosion and flow inside a pipeline as described in any one of claims 1 to 10, characterized in that, The experimental method includes: The corrosion of the top of a large pipeline is simulated by a top simulation unit to monitor the corrosion of the bottom surface of a horizontal tube sheet. Corrosion of the inclined simulation unit is monitored by simulating pipes at different inclination angles using an inclined simulation unit made of metallic material; and / or The flow of the experimental medium within the inclined simulation unit was monitored by simulating pipes at different inclination angles using an inclined simulation unit made of transparent material.

12. The experimental method according to claim 11, characterized in that, Also includes: Correlation analysis was performed on the corrosion monitoring results and flow monitoring results of the two sets of tilted simulation units.

13. The experimental method according to claim 11, characterized in that, Also includes: The corrosion of a humid system is simulated by a separately configured condensation simulation unit, and the corrosion at the top and bottom of the pipes in the condensation simulation unit is monitored.

14. The experimental method according to claim 11, characterized in that, Also includes: By setting up a condensation simulation unit outside the pipe in the top simulation unit, the corrosion of the top of large pipes and the corrosion of the moisture system are simulated, and the corrosion of the bottom surface of the horizontal tube sheet and the condensation droplets and liquid film are monitored and correlated.

15. The experimental method according to claim 11, characterized in that, High-speed cameras or high-speed cameras are used to monitor the flow of the experimental medium within the tilted simulation unit; corrosion probes are used to monitor the corrosion within the tilted simulation unit.

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