Nondestructive testing method for precipitation type soft scale of natural gas wet desulphurization process pipeline

Abstract

The invention relates to the technical field of precipitation type soft scale detection, in particular to a nondestructive detection method for precipitation type soft scale of a natural gas wet desulphurization process pipeline, which comprises the following steps of: performing infrared thermal imaging detection data acquisition on a pipeline detection position by adopting an infrared thermal imager; measuring the wall thickness of the bottom of the pipeline at the detection position by adopting electromagnetic ultrasonic thickness measuring equipment; measuring the distance from the bottom boundary of the pipeline to the center line of the transition area, namely the total thickness of the precipitated soft scale and the bottom pipe wall; and subtracting the thickness of the pipe wall at the bottom of the pipeline to obtain the thickness of the precipitation type soft scale. According to the temperature difference, caused by the precipitation type soft scale, of all parts of the pipeline, the thickness of the precipitation type soft scale in the pipeline is rapidly evaluated through the infrared thermal imaging technology according to the infrared thermal imaging characteristics of the precipitation type soft scale, and the detection cost is low. According to the method, the thickness of the precipitation type soft scale can be evaluated under the condition that production is not stopped and pipes are not opened, and economic losses caused by production stopping and pipe opening to enterprises are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of precipitated soft scale detection, and in particular to a non-destructive detection method for precipitated soft scale in a natural gas wet desulfurization process pipeline. Background Art

[0002] Sour natural gas requires desulfurization before use. Complex iron wet desulfurization technology offers significant advantages in natural gas desulfurization and purification. After complex iron desulfurization, the resulting elemental sulfur is suspended in a rich liquid at 50°C. The rich liquid pipeline is a crucial component of the desulfurization unit, transporting the rich liquid to the filter to remove the sulfur. However, in winter, a sudden drop in temperature can cause the rich liquid temperature in the pipeline to drop, irreversibly destabilizing the suspended sulfur and forming soft scale. This scale then accumulates under the influence of gravity to the bottom of the horizontal rich liquid pipeline. Over time, the deposited scale becomes increasingly thick, eventually causing partial blockage of the desulfurization process pipeline and increasing pressure within the rich liquid pipeline. In severe cases, this can lead to unplanned downtime of the desulfurization unit, resulting in significant economic losses for the company.

[0003] The accumulation of precipitated soft scale in liquid pipelines is crucial for treating deposited scale in rich liquid pipelines. However, there is currently no effective online, non-stop detection method for precipitated soft scale. Determining the accumulation of precipitated soft scale requires shutting down the desulfurization unit and then opening the pipeline, which reduces the desulfurization efficiency of the desulfurization unit. Summary of the Invention

[0004] To address the aforementioned shortcomings of the prior art, the present invention aims to provide a nondestructive detection method for precipitated soft scale in pipelines used in natural gas wet desulfurization processes. This method allows rapid diagnosis of scale accumulation in liquid-rich pipelines without shutting down the process or opening the pipeline. This method avoids the economic losses associated with shutting down the pipeline and improves the ability to assess the thickness of precipitated soft scale.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is: A nondestructive detection method for precipitated soft scale in a natural gas wet desulfurization process pipeline is provided, which comprises the following steps: S1. Draw the pipeline diagram of the rich liquid pipeline of the desulfurization unit: Draw a rich liquid pipeline diagram based on the distribution of rich liquid pipelines in the on-site desulfurization device; S2. Determination of detection position: Using the pipeline pressure monitoring system, identify the horizontally running liquid-rich pipeline where the pressure is abnormally increased. Based on the direction of the rich liquid flow, select a location upstream, midstream, and downstream of the horizontally running liquid-rich pipeline. The location with the thickest scale deposits is the location with the greatest risk of pipeline blockage. S3. Data collection: An infrared thermal imager is used to collect infrared thermal imaging detection data at the detection location. At the bottom of the pipeline at the infrared thermal imaging detection location, an electromagnetic ultrasonic thickness measuring device is used to measure the wall thickness of the bottom of the pipeline at the detection location; S4. Extraction of infrared thermal imaging features of precipitated soft scale blockage: Using infrared thermal imager analysis software, retrieve infrared thermal imaging test data and analyze the infrared thermal imaging characteristics of precipitated soft scale: the upper and lower parts of the pipeline have a large difference in image color, with a gradual color transition zone in the middle; the upper part has a higher temperature and the lower part has a lower temperature; S5. Thickness assessment of precipitated soft scale: Measure the distance from the bottom boundary of the pipeline to the center line of the transition zone, that is, the total thickness of the precipitated soft scale and the bottom pipe wall; then subtract the thickness of the bottom pipe wall from it to get the thickness of the precipitated soft scale.

[0006] Furthermore, in step S3, the infrared thermal imager is turned on and aimed at the pipeline, and unclean parts of the pipeline surface are avoided as much as possible; the focus of the thermal imager is adjusted until the infrared thermal image of the pipeline is clear; the infrared thermal imaging data of the detection position is collected, and the detection position number is recorded.

[0007] The beneficial effects of the present invention are: This method uses infrared thermal imaging technology (IRT) to rapidly assess the thickness of soft scale within pipes, based on the temperature differences caused by precipitated soft scale and its infrared thermal imaging characteristics. This allows for low-cost assessment without interrupting production or opening the pipes, thus avoiding the economic losses that would result from such a shutdown. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 Flow chart of the method of the present invention; Figure 2 Schematic diagram of the horizontal pipe section detection position in the embodiment; Figure 3 This is a schematic diagram of infrared thermal imaging acquisition in the embodiment; Figure 4 Schematic diagram of electromagnetic ultrasonic thickness measurement in the embodiment; Figure 5 Schematic diagram of infrared thermal imaging characteristics of precipitated soft scale in the embodiment. DETAILED DESCRIPTION

[0009] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0010] Example Reference Figure 1 , provides a non-destructive detection method for precipitated soft scale in natural gas wet desulfurization process pipelines, which includes the following steps: Step 1: Draw the pipeline diagram of the rich liquid pipeline of the desulfurization unit.

[0011] Draw a rich liquid pipeline diagram based on the distribution of the rich liquid pipelines in the on-site desulfurization unit. The pipeline diagram should include information such as pipeline direction, pipeline components (such as tees, elbows, reducers, flanges, valves), and rich liquid flow direction.

[0012] Step 2: Determine the detection location The operator's pipeline pressure monitoring system can be used to identify the horizontally rich liquid pipeline where the pressure is abnormally increased. In order to understand the corresponding relationship between the thickness of the deposited scale and the flow direction, one point is selected at the upstream, midstream, and downstream of the horizontally rich liquid pipeline, and the location with the thickest deposited scale is used as the detection location with the greatest risk of blockage in this pipeline. Figure 2 shown.

[0013] Step 3: Data Collection Use an infrared thermal imager to collect infrared thermal imaging data of the inspection area. Turn on the infrared thermal imager and aim it at the pipeline, avoiding the unclean parts of the pipeline surface as much as possible; adjust the focus of the thermal imager until the infrared thermal image of the pipeline is clear; collect the infrared thermal imaging data of the inspection area and record the inspection area number. At the bottom of the pipeline at the infrared thermal imaging inspection area, use electromagnetic ultrasonic thickness measuring equipment to measure the wall thickness δ0 of the bottom of the pipeline at the inspection area. Figure 3-4 shown.

[0014] Step 4: Extraction of infrared thermal imaging features of precipitated soft scale blockage Rich liquid pipes are made of austenitic stainless steel, with diameters ranging from 150 mm to 650 mm and a wall thickness of approximately 5 mm. Precipitated soft scale is sludge-like and accumulates at the bottom of horizontal pipes, with a relatively low thermal conductivity. Rich liquid flows above the precipitated soft scale within the pipes, maintaining a temperature of approximately 50°C. Heat to the walls of rich liquid pipes primarily comes from the rich liquid. Precipitated soft scale accumulates at the bottom of horizontal rich liquid pipes, and its low thermal conductivity causes the pipe wall temperature where the precipitated soft scale comes into contact to be lower than the pipe wall temperature where the rich liquid directly contacts it.

[0015] Use the infrared thermal imager's analysis software to retrieve the infrared thermal imaging detection data. Analyze the infrared thermal imaging characteristics of precipitated soft scale: the image colors of the upper and lower parts of the pipeline are quite different, with a transition zone of gradual color change in the middle; the temperature of the upper part is high and the temperature of the lower part is low. Figure 5 shown.

[0016] Step 5: Thickness assessment of precipitated soft scale Measure the distance h from the bottom boundary of the pipeline to the center line of the transition zone, that is, the total thickness of the precipitated soft scale and the bottom pipe wall; then subtract the thickness of the bottom pipe wall δ0 to obtain the thickness of the precipitated soft scale: δ=h-δ0.

[0017] This method uses infrared thermal imaging technology to rapidly assess the thickness of precipitated soft scale within pipes, based on the temperature differences between various parts of the pipe caused by precipitated soft scale. This method utilizes infrared thermal imaging to rapidly assess the thickness of precipitated soft scale within pipes, resulting in low-cost testing. This method can assess the thickness of precipitated soft scale without stopping production or opening the pipe, thus avoiding the economic losses that would otherwise be incurred by the company.

[0018] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0019] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A non-destructive detection method for precipitated soft scale in natural gas wet desulfurization process pipelines, characterized in that: The following steps are involved: S1. Draw the pipeline diagram of the rich liquid pipeline of the desulfurization unit: Draw a rich liquid pipeline diagram based on the distribution of rich liquid pipelines in the on-site desulfurization device; S2. Determination of detection position: Using the pipeline pressure monitoring system, identify the horizontally running liquid-rich pipeline where the pressure is abnormally increased. Based on the direction of the rich liquid flow, select a location upstream, midstream, and downstream of the horizontally running liquid-rich pipeline. The location with the thickest scale deposits is the location with the greatest risk of pipeline blockage. S3. Data collection: An infrared thermal imager is used to collect infrared thermal imaging detection data at the detection location. At the bottom of the pipeline at the infrared thermal imaging detection location, an electromagnetic ultrasonic thickness measuring device is used to measure the wall thickness of the bottom of the pipeline at the detection location; S4. Extraction of infrared thermal imaging features of precipitated soft scale blockage: Using infrared thermal imager analysis software, retrieve infrared thermal imaging test data and analyze the infrared thermal imaging characteristics of precipitated soft scale: the upper and lower parts of the pipeline have a large difference in image color, with a gradual color transition zone in the middle; the upper part has a high temperature and the lower part has a low temperature; S5. Thickness assessment of precipitated soft scale: Measure the distance from the bottom boundary of the pipeline to the center line of the transition zone, that is, the total thickness of the precipitated soft scale and the bottom pipe wall; then subtract the thickness of the bottom pipe wall from it to get the thickness of the precipitated soft scale.

2. The nondestructive detection method for precipitated soft scale in natural gas wet desulfurization process pipeline according to claim 1 is characterized in that: In step S3, the infrared thermal imager is turned on and aimed at the pipeline, and unclean parts of the pipeline surface are avoided as much as possible; the focus of the thermal imager is adjusted until the infrared thermal image of the pipeline is clear; the infrared thermal imaging data of the detection position is collected, and the detection position number is recorded.

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