Calculation method of river channel pebble boundary oil spill adsorption capacity

Abstract

The invention discloses a riverway pebble boundary oil spill adsorption capacity calculation method, which comprises the following steps: carrying out oil film gray scale-thickness relation calibration based on a pebble boundary oil spill adsorption test, and establishing an oil film gray scale-thickness calculation model of a target oil product; obtaining an oil spill adsorption image of the target oil product in the to-be-monitored area, and carrying out graying processing to obtain an oil film grayscale image; the image gray scale of the oil film gray scale image is calculated, and the oil film thickness of the target oil product is obtained according to an oil film gray scale-thickness calculation model; calculating according to the thickness of the oil film to obtain the pebble river bank boundary adsorption capacity of unit length at a certain moment and the unit generalized oil spilling body mass; and based on the equivalent particle size of the river pebbles, calculating to obtain the oil spill adsorption quantity of the river pebble boundary. And the image gray scale of the oil film gray scale image is used as an intermediate value, so that the detection efficiency of the oil film thickness can be improved on the premise of improving the detection universality, and the detection precision of the spilled oil adsorption quantity is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of measuring and calculating the amount of oil spill adsorption in inland river basins, and specifically designs a method for calculating the amount of oil spill adsorption at a river pebble boundary. Background Art

[0002] With the high-quality development of the economy, oil has become a basic supporting industry in my country. As a non-renewable resource, it has a profound impact on the development of the economy. However, my country's terrestrial oil resources are very scarce. In recent years, the growth rate of oil exploration and production has been slow, and the annual output is far from enough to meet my country's oil demand. The exploitation and transportation of oil often cause marine and river pollution incidents. Once an oil spill occurs, it will cause great environmental pollution and damage. After crude oil leaks into the ocean, the oil film will cover the sea surface and drift. The oil spill film may float on the coast, which will affect the safety and health of the people living in the surrounding area, and cause unsightly phenomena, and even affect the tourism income of coastal cities. Crude oil contains various organic substances such as hydrocarbons and inorganic substances such as nickel and vanadium, which will cause great damage to the quality of marine water. In addition, the density of oil is generally less than that of water, and it has a strong viscosity, which will keep the oil film floating on the water.

[0003] At present, a large number of oil spill studies focus on oil spill tracking and marine oil spill absorption, but the research on oil spill absorption in inland river basins is relatively weak. Compared with marine basins, inland river basins are shorter and have faster water flow, so oil spills are more likely to spread and contact the shore, causing great harm to people's normal lives. Therefore, the research and calculation of oil spill absorption in inland river basins has important practical value and significance.

[0004] However, compared with the ocean surface, the width of inland river basins is narrower and is easily affected by major hydraulic factors such as river surface morphology and local water surface characteristics. Therefore, river pollutants are prone to approach and adhere to beaches and concave bank boundaries where water flow exchange is slow. In addition, there are many types of inland river boundaries in my country, especially pebble boundaries. Therefore, for inland river oil spill pollution, the adsorption characteristics of pebble boundaries must be considered. Summary of the invention

[0005] The present invention provides a method for calculating the amount of oil spill adsorption at a river pebble boundary. By analyzing the influence of influencing factors such as the composition, particle size, and gradation of the pebble boundary existing in an inland river on the amount of oil spill adsorption, a formula for the change of the cumulative adsorption amount of the pebble boundary over time is obtained. The method can take into account both the versatility and efficiency of the calculation of the amount of oil spill adsorption at the river pebble boundary, thereby improving the accuracy of the calculation result of the amount of oil spill adsorption at the river pebble boundary.

[0006] A method for calculating the amount of oil spill adsorption at a river pebble boundary comprises the following steps:

[0007] Step 1: calibrate the grayscale-thickness relationship of the oil film based on the pebble boundary oil spill adsorption test, and establish an oil film grayscale-thickness calculation model for the target oil product;

[0008] Step 2: Obtain an oil spill adsorption image of the target oil product in the area to be monitored, and perform grayscale processing to obtain an oil film grayscale image;

[0009] Step 3, calculating the image grayscale of the oil film grayscale image, and obtaining the oil film thickness of the target oil product according to the oil film grayscale-thickness calculation model;

[0010] Step 4, according to the oil film thickness, the adsorption amount of the pebble riverbank boundary per unit length at a certain moment and the unit generalized oil spill mass are calculated;

[0011] Step 5: Based on the equivalent particle size of river pebbles, the oil spill adsorption capacity at the river pebble boundary is calculated using the following formula:

[0012]

[0013] Among them, M R is the amount of oil spill adsorbed by the river pebble boundary; M0 is the unit generalized oil spill mass at a certain moment; t is the total pebble adsorption time; l is the actual river pebble boundary adsorption length; α, β, k are the adsorption coefficients corresponding to the equivalent particle size of river pebbles.

[0014] Furthermore, the expression of the oil film grayscale-thickness calculation model of the target oil product is:

[0015] y=-ax+b,

[0016] Among them, y is the oil film thickness; x is the oil film grayscale; a is the coefficient; b is a constant.

[0017] Furthermore, the steps for calibrating the grayscale-thickness relationship of the oil film based on the pebble boundary oil spill adsorption test in step 1 are as follows:

[0018] Step 1.1, fix the test container under the camera and lay a white anti-scratch cloth under the test container;

[0019] Step 1.2: Use pebbles of different or the same particle size to build a simulated river pebble boundary in a test container, and add clean water into the test container;

[0020] Step 1.3, adding a dye to the target oil product in proportion to prepare a target oil product solution;

[0021] Step 1.4, inject a certain mass of target oil solution into the central area of ​​the clean water in the test container;

[0022] Step 1.5, using a camera to obtain an oil film image when the target oil solution expands in clean water to cover the surface of the test container, performing image grayscale processing on the oil film image and calculating the image grayscale, and at the same time calculating the corresponding oil film thickness according to the amount of oil spill;

[0023] Step 1.6, repeating steps 1.2 and 1.5 for multiple times, and obtaining multiple groups of target oil solution image grayscale and corresponding oil film thickness data groups by changing the pebble particle size and oil filling amount;

[0024] Step 1.7, calibrate the oil film grayscale-thickness relationship based on multiple groups of target oil image grayscales and corresponding oil film thickness data groups to obtain an oil film grayscale-thickness calculation model for the target oil.

[0025] Furthermore, the calculation formula for the corresponding oil film thickness calculated according to the oil spill volume in step 1.5 is:

[0026]

[0027] Among them, h t is the oil film thickness; m1 is the weight of the test container when no oil is dripped; m2 is the weight of the test container after oil is dripped; ρ is the density of the mixed hydraulic oil; s is the surface area of ​​the oil film.

[0028] Furthermore, in step 1.5, a camera is used to obtain an oil film image when the target oil solution is expanded in clean water to cover the surface of the test container, and the process of performing image grayscale processing on the oil film image and calculating the image grayscale is as follows:

[0029] A camera is used to record the entire process of the target oil solution spreading in clean water until it covers the entire surface of the test container;

[0030] Smart Player video processing software is used to process the video data. In the oil film expansion stage, a video screenshot is taken at a first time interval; in the oil film adsorption stage, a video screenshot is taken at a second time interval;

[0031] The image obtained by screenshot was gray-processed using ImageJ image processing software until the desired oil film gray-scale image was obtained when the image gray-scale value remained unchanged, and the image gray-scale was calculated based on the oil film gray-scale image.

[0032] Furthermore, the value of the second duration is not less than the value of the first duration.

[0033] Furthermore, in step 4, the calculation formula for the adsorption amount per unit length of the pebble riverbank boundary at a certain moment is calculated according to the oil film thickness:

[0034]

[0035] Among them, M A is the amount of oil spill adsorbed by the pebble boundary per unit length; M0 is the mass of the generalized unit oil spill body; t is the total adsorption time of the pebble; t0 is the stable adsorption time; α, β, k are the adsorption coefficients related to the equivalent particle size of the river pebbles.

[0036] Furthermore, the calculation formula for the unit generalized oil spill mass in step 4 is:

[0037] M0=V0·ρ

[0038] Where M0 is the unit oil spill mass; V0 = a·b·d t is the volume of the oil spill per unit length; a and b are the length and width of the oil spill per unit length; d t is the oil film thickness per unit oil spill; ρ is the density of the target oil.

[0039] Furthermore, the calculation formula of the equivalent particle size of the river pebbles is:

[0040]

[0041] Among them, d e is the equivalent particle size; d i is the actual particle size of the pebble; r i is the particle size d i The proportion of pebbles of different sizes; n is the number of types of pebbles of different sizes.

[0042] Furthermore, the relationship between the adsorption coefficients α, β, k and the equivalent particle size of river pebbles is as follows:

[0043] α=c1*d e +f1;

[0044] β=-c2*d e +f2;

[0045] k=c3*d e +f3;

[0046] Among them, c1, c2, and c3 are coefficients related to equivalent particle size, d e is the equivalent particle size; f1, f2, f3 are constants.

[0047] Beneficial effects:

[0048] 1. In this scheme, the grayscale-thickness relationship of the oil film is first calibrated based on the pebble boundary oil spill adsorption test, and the oil film grayscale-thickness calculation model of the target oil is established; the oil spill adsorption image of the target oil in the monitored area is obtained, and the oil film grayscale image is obtained by grayscale processing; then the image grayscale of the oil film grayscale image is calculated, and the oil film thickness of the target oil is obtained according to the oil film grayscale-thickness calculation model; then, the adsorption amount of the pebble riverbank boundary per unit length at a certain moment and the unit generalized oil spill mass are calculated according to the oil film thickness; finally, based on the equivalent particle size of the river pebbles, the oil spill adsorption amount of the river pebble boundary is calculated. In this scheme, the image grayscale of the oil film grayscale image is used as the intermediate value. On the one hand, the oil film image after image grayscale processing can well highlight the oil film area and can weaken the spectral reflection of water quality, so that it can well avoid the limitation of water quality and improve the versatility of oil film thickness detection; on the other hand, the oil film image after image grayscale processing has less information, which can greatly simplify the calculation process, so that the detection efficiency of oil film thickness can be improved while improving the versatility of detection; in addition, the applicant found in the experiment that the image grayscale of the oil film grayscale image has a good correlation with the oil film thickness, which can ensure the detection accuracy of the oil film thickness and the amount of oil spill adsorption.

[0049] 2. The method for calculating the amount of oil spill adsorption at the river pebble boundary based on the pebble boundary oil spill adsorption test in this scheme can take into account the versatility and efficiency of oil film thickness detection, and can ensure the calculation accuracy of the oil spill adsorption amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A method flow chart of the calculation method according to an embodiment of the present invention;

[0051] Figure 2 It is a schematic diagram of the oil film grayscale-thickness calibration test results in the present invention;

[0052] Figure 3 It is a schematic diagram of the calibration verification result of the oil film grayscale-thickness relationship in the present invention;

[0053] Figure 4 It is a schematic diagram of the change of oil film area with time in each working condition during the expansion stage of the uniform particle size pebble boundary;

[0054] Figure 5 It is a schematic diagram of the variation of oil film thickness with time in each working condition during the expansion stage of the uniform-size pebble boundary;

[0055] Figure 6 It is a schematic diagram of the change of oil film grayscale with time in each working condition during the expansion stage of the uniform particle size pebble boundary;

[0056] Figure 7 It is a schematic diagram of the calibration structure of the grayscale-thickness relationship of each working condition in the boundary expansion stage of uniform-size pebbles;

[0057] Figure 8 It is a schematic diagram of the change of oil film area with time in each working condition during the expansion stage of the non-uniform particle size pebble boundary;

[0058] Fig. 9 It is a schematic diagram of the variation of oil film thickness with time in each working condition during the expansion stage of the non-uniform particle size pebble boundary;

[0059] Fig.10 It is a schematic diagram of the change of oil film grayscale with time in each working condition during the expansion stage of the non-uniform particle size pebble boundary;

[0060] Fig.11 It is a schematic diagram of the grayscale-thickness relationship calibration for each working condition in the expansion stage of the boundary of non-uniform-size pebbles;

[0061] Fig.12 It is a schematic diagram of the variation of oil film thickness with time during the adsorption stage of the oil spill test on the boundary of pebbles with different particle sizes under uniform particle size;

[0062] Fig.13 It is a schematic diagram of the stable adsorption capacity of the pebble boundary under various working conditions;

[0063] Fig.14 It is a schematic diagram of the adsorption capacity per unit length of each particle size group;

[0064] Fig.15 is the equivalent particle size d e And the fitting diagram of each parameter;

[0065] Fig.16 It is a principle block diagram of the computing system described in an embodiment of the present invention. DETAILED DESCRIPTION

[0066] The present invention is further described below in conjunction with embodiments and drawings.

[0067] If an oil spill occurs in an inland waterway, the oil film will first expand, and the area of ​​the oil film will gradually increase until it floats to the boundary. The oil film will first adhere to the boundary surface, and when the boundary surface is saturated, the oil film will continue to penetrate into the pores inside the boundary, and this stage will continue until the boundary is fully adsorbed. Therefore, this embodiment proposes a method for calculating the amount of oil spill adsorption at the river pebble boundary based on an oil spill adsorption test.

[0068] like Figure 1 As shown, an embodiment of the present invention provides a method for calculating the amount of oil spill adsorption at a river pebble boundary, comprising the following steps:

[0069] Step 1: calibrate the grayscale-thickness relationship of the oil film based on the pebble boundary oil spill adsorption test, and establish an oil film grayscale-thickness calculation model for the target oil product;

[0070] The oil spill absorption test is based on the image of the photographic equipment and the image is analyzed by software to obtain the grayscale of each image, establish the grayscale-thickness correspondence of the oil film image in the oil spill absorption test, and calculate the oil film thickness through the grayscale of the oil film image. In order to ensure that the intensity and direction of the irradiation light source remain constant during the test, incandescent energy-saving lamp sources are laid in sequence at a certain interval of 5 cm above the test container and the operating area.

[0071] Before the test, a light shielding shed was built to ensure consistent light intensity and eliminate interference from changes in external light intensity. A level tester was used to check whether the floor surface was flat to ensure that the test container was built on a flat floor surface and to prevent gravity-based diffusion in the overflow direction of the oil film in the test container due to uneven site conditions. In order to continuously monitor the grayscale changes of the oil film over time in the oil spill adsorption test, 10 high-definition cameras were installed in the test container at intervals of 50 cm, as the range of a single camera is limited. Each camera can transmit the monitoring image to the display in real time, and has time recording and video storage functions, which is convenient for test personnel to perform test operations in the operation area.

[0072] This test requires the construction of different pebble boundaries as the boundary conditions of the test. Considering the water flow characteristics and oil spill characteristics, a PE tendon round basin is selected as the test container. The material used in this test container is linear low-density polyethylene LLDPE raw material, which will not affect the adsorption effect of the test oil.

[0073] The main oil in oil spill accidents is hydraulic oil. Before the formal test, a large number of preliminary experiments were carried out to select the oil. It is understood that the kinematic viscosity of conventional hydraulic oil on the market is 40-130mm 2 / s. Therefore, a hydrostatic expansion test was conducted on this batch of hydraulic oil to determine whether it has good expansibility. The test results show that when the kinematic viscosity of the hydraulic oil is lower than 55mm 2 / s, after this type of hydraulic oil drops into the water surface, it quickly diffuses to the boundary and the oil film will rupture. Therefore, this type of hydraulic oil does not meet the requirements of the test due to its fast diffusion speed. When the kinematic viscosity of the hydraulic oil is greater than 110mm 2 / s, it is difficult for this type of hydraulic oil to diffuse to the boundary after dripping into the water surface. Therefore, when the diffusion speed of the hydraulic oil is extremely slow, it does not meet the test requirements. In multiple groups of preliminary experiments, a kinematic viscosity of close to 100mm 2 / s and density is 0.8g / cm 3 The hydraulic oil has a moderate diffusion rate in the hydrostatic expansion test, can reach the boundary within a reasonable time range, and the oil film is not prone to rupture.

[0074] In this example, the steps for calibrating the grayscale-thickness relationship of the oil film based on the pebble boundary oil spill adsorption test are as follows:

[0075] Step 1.1: In the oil spill adsorption test room, isolate the external light source with a blackout cloth to ensure that only incandescent light is received. At the same time, record the changes in temperature and humidity to eliminate errors caused by large environmental changes in some working conditions. Fix the test container under the camera and lay a white anti-scratch cloth under the test container to prevent grayscale errors caused by the color of the floor surface being similar to the color of the oil film.

[0076] Step 1.2: Use pebbles of different or the same particle size to build a simulated river pebble boundary in a test container, and add clean water into the test container;

[0077] In this example, the pebbles are polished white pebbles. A certain number of pebbles are placed on a 5mm iron screen, the iron screen is placed on a cleaning workbench, and detergent is evenly applied to each pebble. Finally, a high-pressure water gun is used to clean the pebbles one by one in the same order, so that the mud, dust and other turbidities attached to the pebbles can be quickly separated from the surface of the pebbles by the water pressure and their own gravity. Then, through the external faucet, the water volume is adjusted to a small amount and water is slowly poured into the middle of the test basin to avoid washing away the accumulated pebbles. And always observe the ruler scale until the water depth reaches the test requirements.

[0078] Step 1.3, adding a dye to the target oil product in proportion to prepare a target oil product solution;

[0079] In the specific implementation, add the dye in a ratio of 100:1. Since the dye is in powder form, use a small spoon to add it to the beaker gradually according to the principle of adding more rather than less, and always pay attention to whether the weight on the precision electronic scale meets the requirements. Filter the hydraulic oil with the dye added with a 100-mesh sieve, and finally stir it gently in a clockwise direction with a glass for 5-8 minutes until the mixed hydraulic oil has no precipitation and impurities.

[0080] Step 1.4, inject a certain mass of target oil solution into the central area of ​​the clean water in the test container;

[0081] After the water surface is still for 10 minutes, use a beaker with a spout to slowly drip oil into the middle of the water area using the one-time oil injection method. Control the oil output to be very small and in a linear shape. Adjust the camera to ensure that the central area captured by the camera is the test container. Check whether the light source and the blackout curtain are in normal condition to prevent external light sources from interfering with the test.

[0082] In this example, the target oil solution is injected using the front and rear oil volume difference method.

[0083] Step 1.5: Use a camera to obtain an oil film image when the target oil solution expands in clean water to cover the surface of the test container, perform image grayscale processing on the oil film image and calculate the image grayscale, and calculate the corresponding oil film thickness according to the amount of oil spill. The specific process is as follows:

[0084] After the oil film diffuses for 15 hours, the oil spill adsorption test under this condition is completely completed. During this process, a camera is used to record the entire process of the target oil solution expanding in clean water until it covers the surface of the test container, and the video is later copied to a mobile hard disk through a video recording system;

[0085] Smart Player video processing software was used to perform lossless screenshots of the video data and save them in bmp mode. During the oil film expansion stage, the video data was captured every 5 minutes. Figure 1 times; in the oil film adsorption stage, when the oil film reaches the complete boundary, the Figure 1 When in the diffusion period, the oil film area changes more, the color of the oil film dye changes faster, resulting in a faster grayscale change rate, so the screenshots are taken at 5-minute intervals. When in the adsorption period, the oil film area hardly changes, the dye color changes more slowly, and the grayscale change rate is also relatively slow, so the screenshots are taken at 10-minute intervals. Figure 1 This screenshot technique greatly shortens the workload while ensuring data reliability, and the method is highly feasible;

[0086] The image obtained by screenshot was gray-processed using ImageJ image processing software until the desired oil film gray-scale image was obtained when the image gray-scale value remained unchanged, and the image gray-scale was calculated based on the oil film gray-scale image.

[0087] ImageJ is an extensible image processing software developed based on JAVA language. The design interface is very simple and can be easily connected to image processing libraries such as scipy, scikit-image, and opency. This software can display, edit, process, and save images of various bit numbers and formats. The image processing principle of ImageJ has been explained in detail in the "Study on Oil Spill Adsorption Experiment at Different River Boundaries", so I will not repeat it here. Since the default unit of ImageJ image processing software is pixel, there is asymmetry between the units and the actual size of the test. Therefore, the first step in using this image software is to convert the image unit based on the actual reference object or test object size of this test.

[0088] Step 1.6, by changing the pebble particle size and the amount of oil, repeat steps 1.2 and 1.5 for multiple times. After each test, a 360° bottom vortex water suction pump is placed in the middle of the test basin to suck out all the test water. After all the water in the test basin is pumped out, the test pebbles are cleaned to obtain multiple groups of target oil solution image grayscale and corresponding oil film thickness data groups;

[0089] In the specific implementation process, the calculation formula of oil film thickness can be deduced from a simple mathematical formula:

[0090]

[0091] Where: h is the oil film thickness, mm; m is the oil film mass, g; ρ is the oil film density, g / cm 3 ; s is the oil film area, cm 2 .

[0092] This idea is further extended to the oil spill adsorption test. Since hydraulic oil has strong adhesion and will remain on the cup wall and other places, the mass difference method is used to determine the mass of the hydraulic oil dripped in, that is, m1-m2. There is no difference in the physical properties of the hydraulic oil and the mixed hydraulic oil with added dye, and its density ρ can be obtained by measurement. This test is carried out in a completely closed test basin, and the surface area can be measured by capturing the photos taken by its camera. Therefore, the simple oil film thickness calculation formula can be deduced as:

[0093]

[0094] Where: h t is the oil film thickness, cm; m1 is the weight before oil dripping, g; m2 is the weight after oil dripping, g; ρ is the density of the mixed hydraulic oil, g / cm 3 ; s is the oil film surface area, cm 3 .

[0095] Before the oil film diffuses to the boundary, the oil film area gradually increases, the oil film base color changes, and the oil film thickness gradually decreases. When the oil film diffuses to the boundary, the oil film area has reached the maximum value and will not change, but the oil film base color and oil film thickness will still change within a certain range. At this time, if the oil film thickness calculation formula is simply used, the error will be very large. Therefore, it is necessary to establish the relationship between the grayscale and thickness of the oil film, and reflect the change of the oil film base color through the grayscale change, so as to find the change law of the thickness.

[0096] In order to increase the applicability of the grayscale-thickness relationship of the oil film, this embodiment designs a series of gradient oil dripping amounts. The amount of oil dripped is the difference between the front and rear oil amounts to increase the accuracy of the test. The specific test measurement results are shown in Table 1 below.

[0097] Table 1 Test measurement results

[0098]

[0099] Step 1.7, calibrate the oil film grayscale-thickness relationship based on multiple groups of target oil image grayscales and corresponding oil film thickness data groups to obtain an oil film grayscale-thickness calculation model for the target oil.

[0100] Combining Table 1 and Figure 2 It can be clearly seen that when the amount of oil dripped is 1.58g, when the hydraulic oil dripped is completely diffused to the boundary, the thickness is 0.617mm, and the corresponding grayscale is 109.141. As the amount of oil dripping continues to increase, under the premise of limited oil overflow bottom area and no oil adhering to the beaker glass boundary, the thickness of the oil film continues to increase. When the oil film thickness is between 0.617mm and 2.201mm, the corresponding grayscale changes from 109.140 to 34.805. At this time, the grayscale changes linearly with the thickness, and its determination coefficient is 0.9968, such as Figure 3 As shown, it means that the regression line has a good fit to the observed value. When the thickness is 2.46mm to 10.230mm, the corresponding grayscale is 30.35 to 10.367. As the thickness gradually increases, the corresponding grayscale tends to decrease, and the grayscale change also tends to decrease, and the change is not obvious. This is because when the oil film thickness is thicker, the diffusion range between the hydraulic oil dye molecules becomes smaller and the interaction force increases, resulting in the hydraulic oil dye color change is not obvious. Through preliminary experiments, it was found that when the bottom area of ​​the test basin is large enough and the amount of oil that meets the test conditions is dripped, the oil film thickness mainly varies between 0-2.2mm, so this test mainly calibrates this part of the thickness-grayscale.

[0101] Therefore, this embodiment is calibrated for the working condition where the oil film thickness is within 2.2 mm, and the relationship can be obtained as shown in the following formula:

[0102] y=-0.0208x+2.8747 (3)

[0104] Where: x is the grayscale of the oil film; y is the thickness of the oil film, mm.

[0105] In order to ensure the accuracy of the obtained oil film grayscale-thickness calculation model, this embodiment also carried out multiple generalized oil spill tests with uniform particle size pebbles and non-uniform particle size pebbles, as follows:

[0106] 1) Pebble boundary oil spill extension test with uniform particle size

[0107] In order to prevent systematic errors, three parallel test groups were set up for each working condition. The working conditions of the generalized oil spill adsorption test with pebbles of uniform particle size are shown in Table 2 below.

[0108] Table 2 Generalized oil spill adsorption test conditions of pebbles with uniform particle size

[0109]

[0110]

[0111] The morphology of the oil film expansion stage was divided into different time intervals. The camera equipment was used to record lossless videos and take screenshots at pre-set time intervals. The Smart Player screenshots of the oil spill film were analyzed, and the area and grayscale were measured using ImageJ. The real-time thickness was calculated using formula (2). The changes of the oil film area of ​​1 cm single-size pebbles in each working condition over time during the expansion stage are shown in the figure. Figure 4 As shown, curve 1 represents the working condition where the amount of oil in a drop is 60g and the initial area of ​​this working condition is 234.342cm 2 At this time, the oil film area is circular and expands in all directions. Due to the strong gravity effect on the oil film in the early stage, the flattening phenomenon is more obvious. The oil film expands rapidly over a period of time. In condition 1, the oil film area reaches 1180cm at 83 minutes. 2 At this stage, the oil film spreads fastest. Subsequently, due to the reduction of gravity, the viscosity and inertia of the oil film shrink, causing the flattening speed to gradually slow down. For a long time, the oil film is mainly affected by shear force, its own internal viscosity and surface tension. At 105 minutes, the area reaches a maximum of 1257.06cm 2 The oil drop amount in working condition 2 is 80g. Due to the increase in oil amount, the gravity phenomenon is more obvious than that in working condition 1. The initial area after oil drop is 327.142cm 2 The oil film area increases linearly in the first 60 minutes. The expansion phase of this condition is completed at nearly 100 minutes, and the area at the end is 1256.85 cm 2 The oil drop amount in working condition 3 is 100g. The diffusion speed of the oil film increases with the increase of the oil drop amount. The oil film diffusion stage is completed at 66 minutes. The area of ​​the oil film at this time is 1256.32cm 2 The increase in oil film diffusion per minute is 12.877 cm 2 / min. In working condition 4, the maximum oil drop amount is 120g. The initial area of ​​the oil film is proportional to the oil drop amount. The initial area of ​​the oil film is 445.347cm 2 The diffusion rate of the oil film increased linearly within 43 minutes, and finally the area of ​​the oil film completed the diffusion stage at 51 minutes. At this time, the oil film area was 1257.06 cm 2 The increase in oil film diffusion per minute is 15.916 cm 2 / min.

[0112] The variation of oil film thickness over time is shown in Figure 5 As shown, the four oil spill amounts change accordingly to 60g, 80g, 100g, and 120g respectively. Taking the oil dripping time as the initial time point, the expansion stage of the oil film is observed. In the expansion stage, the thickness of the oil film will first show a rapid decay period, and then gradually stabilize. The initial thickness of working condition one is 3.307mm. In the time period of 0-62min, the thickness of the oil film changes rapidly, with a change of -2.576mm, and the thickness decay per minute is -0.042mm / min. From 62 to 105min is the stable expansion period of this working condition, during which the oil film thickness changes relatively slowly, with a change value of -0.115mm. The initial thickness of working condition two is 3.139mm, and the oil film thickness changes rapidly in the period of 0-50min, during which the oil film thickness changes by -2.193mm. Then the oil film thickness entered a stable period of change, which lasted for 46 minutes. The oil film thickness changed by -0.129mm, and the thickness decayed by -0.003mm / min per minute. The initial thickness of working condition three was 3.198mm. The oil film thickness changed rapidly from 0 to 44 minutes, with a change of -2.059mm and a thickness decay of -0.047mm / min per minute. Subsequently, the oil film thickness showed a slow change stage. From 44 to 66 minutes, the final thickness of the oil film in the extended stage of the working condition was 1.033mm, the oil film changed by -0.106mm, and the thickness decayed by -0.048mm / min per minute. The initial thickness of working condition four was 3.149mm. In the time period of 0 to 34 minutes, the oil film thickness changed rapidly, with a change of -1.992mm and a thickness decay of -0.059mm / min per minute. The period from 34 to 51 minutes is a stable expansion period for this working condition. During this period, the oil film thickness changes slowly, with a change value of -0.042mm and a thickness attenuation of -0.025mm / min per minute.

[0113] The grayscale of the oil film changes with time. Figure 6 As shown in Figure 2, the initial grayscale values ​​of the four working conditions are all between 19 and 26 with little difference. As the oil film expansion process continues, the oil film area gradually increases, resulting in an increase in the corresponding grayscale value. In the early stage of the oil film expansion process, the oil film area growth value is relatively large. Figure 4As shown in the figure, the color of the oil film corresponding to this stage becomes lighter and the gray value of the oil film increases rapidly. Then it enters the expansion and stable period. The gravity force on the oil film decreases, which slows down the increase of the oil film area. In fact, the viscosity and inertia force inside the oil film play a leading role. The thickness of the oil film decays slowly, so the change of the gray value of the oil film decreases. As can be seen from the figure below, the initial gray values ​​of the four working conditions are not much different. After experiencing the rapid change period of the gray value of the oil film, the gray value of each working condition reaches a certain stable value range. The gray value of working condition one is as high as 105.432. This is because the amount of oil dripping in this working condition is the least, and the thickness of the oil film is the thinnest at the end of the expansion stage, which leads to the lightest color of the oil film. It can be seen that with the increase of the amount of oil dripping, the gray value of the oil film in the expansion stage of the four working conditions continues to increase, showing a proportional phenomenon. The final gray value of the expansion stage of working condition four is 51.35. The amount of oil dripping in this working condition is the largest and the color of the oil film is the darkest.

[0114] The grayscale-thickness relationship was calibrated for the free water surface expansion stage under four working conditions. The results are as follows: Figure 7 As shown in the figure, it can be found that for the working condition with oil film thickness within 2.2 mm, the calibration is carried out and it is found that the determination coefficients R2 of the four working conditions are 0.9964, 0.9956, 0.9797 and 0.9822 respectively, which shows that the grayscale and thickness have a good linear relationship in the expansion stage, which proves the correctness of the obtained oil film grayscale-thickness calculation model.

[0115] 2) Oil spill extension test on pebble boundary with non-uniform particle size

[0116] During the test, three parallel test groups were set up for each group of working conditions to prevent systematic errors. The working conditions of the pebble-like oil spill adsorption test with non-uniform particle size are shown in Table 3 below.

[0117] Table 3 Generalized oil spill adsorption test conditions of pebbles with uniform particle size

[0118]

[0119] The images of the oil film expansion stage are captured at certain time intervals. The changes of the oil film area and thickness over time in the expansion stage of the four working conditions of the non-uniform particle size pebble oil spill adsorption test are shown as follows: Figure 8 , Fig. 9 The change of oil film grayscale with time under four working conditions is shown in Fig.10 The relationship between grayscale and thickness in the expansion stage under four working conditions of the non-uniform particle size pebble oil spill adsorption test is shown in Fig.11 As shown. 2 They are 0.9874, 0.9826, 0.9819 and 0.9794 respectively, indicating a good degree of fit.

[0120] It can be seen that, whether it is the expansion stage of the oil spill test with uniform or non-uniform particle size pebbles, the numerical changes in area, grayscale, and thickness at this stage are not much different. After the oil spill test oil film is completed, due to the action of gravity in a very short time, the surface tension also helps the expansion of the oil film, and then it is mainly affected by shear force, internal viscosity of the oil film (viscosity of dragging water) and inertial force, and the change rate of each parameter gradually slows down. When the oil film does not touch the boundary, the expansion of the oil film at this stage is not affected by any boundary conditions, that is, the changes of various parameters (area, grayscale, thickness) at this stage are not affected by boundary conditions.

[0121] Since most natural river channels have uneven pebble boundaries, it is very necessary to study the oil spill test on uneven pebble boundaries. ImageJ was also used to determine the gray value, and formula (3) was used to calculate the thickness value. It was found that the overall trend was that the rate of change first increased, then slowed down, and finally gradually stabilized.

[0122] Step 2: Obtain an oil spill adsorption image of the target oil product in the monitored area, and perform grayscale processing to obtain an oil film grayscale image. The method for obtaining the oil film grayscale image in this step is the same as that in step 1;

[0123] Step 3, calculating the image grayscale of the oil film grayscale image, and obtaining the oil film thickness of the target oil product according to the oil film grayscale-thickness calculation model;

[0124] According to the grayscale-thickness calculation model of the oil film determined on the free water surface, and through repeated verification in the extended stage of the pebble boundary oil spill test, it can be proved that the grayscale and thickness are linearly related and have good fitting. From the adsorption stage, the oil film area on the free water surface will not change, and the oil film will only change the thickness, grayscale value, etc. The grayscale value of the adsorption stage is measured by ImageJ, and the corresponding oil film thickness is calculated using formula (3).

[0125] Step 4, according to the oil film thickness, the adsorption amount of the pebble riverbank boundary per unit length at a certain moment and the unit generalized oil spill mass are calculated;

[0126] Based on the calculated oil film thickness, the adsorption amount is back-calculated using equations (4) and (5).

[0127] m t =d t ×ρ×S (4)

[0128] Where: dt is the instantaneous oil film thickness, mm; ρ is the oil film density, g / cm 3 ; S is the oil film surface area, cm 2 .

[0129] m a =mi -m t (5)

[0130] Where: m a is the adsorption amount at the pebble boundary, g; m i is the initial oil drop volume of the test, g; m t is the amount of oil in the test waters, g.

[0131] In order to make the adsorption amount related formula have practical engineering significance, the unit length of the oil spill body M0 is introduced, and the unit length of the oil spill body volume V0 is introduced. The calculation formula of the oil spill body volume is shown in formula (6), and the calculation formula of the unit generalized oil spill body mass M0 is shown in formula (7):

[0132] V0=a×b×d t (6)

[0133] M0=V0×ρ (7)

[0134] Where: a, b are the length and width of the unit oil spill, both are 1m; d t The thickness of the unit oil spill, m; ρ is the unit density of the oil, kg / m 3 , M0 is the unit mass of the oil spill, kg; V0 is the unit length of the oil spill, m 3 .

[0135] The data obtained in this test are based on a specific test container, and the length of the pebble boundary is a fixed value. In order to make the subsequent derivation formula have practical engineering significance, the pebble boundary adsorption amount m obtained in the test is a , further deduced to be the adsorption amount M of the pebble river bank per unit length of 1m A , and its calculation formula is shown in formula (8):

[0136]

[0137] Where: M A is the actual adsorption amount at the pebble riverbank boundary, kg; m a is the adsorption capacity of the test pebble boundary, kg; l0 is the length of the test pebble boundary, m; l1 is the length of the 1 m pebble bank boundary, m.

[0138] In addition, in actual river pebble boundaries, the pebble boundaries that constitute the riverbed are almost all non-uniform pebbles. In order to explore the relationship between the adsorption of each particle size group in the pebble oil spill test and the change in particle size, and the thickness is obtained by the grayscale through a calculation formula, it is only necessary to compare the thickness here, and study the changes in the thickness of pebbles of all particle sizes (including uniform and non-uniform) together. Since each group of experiments has four working conditions corresponding to four oil drop amounts, the oil drop amount is used as a variable for separate studies. The experimental conditions and working conditions of each group of experiments are the same. The change in oil film thickness over time during the adsorption stage of the oil spill test on pebble boundaries of different particle sizes under uniform particle size is shown below. Fig.12 As shown, Fig.12 The oil drop amount of (a) is 60g, Fig.12 The oil drop amount of (a) is 80g, Fig.12 The oil drop amount of (a) is 100g, Fig.12 The amount of oil dripped from (a) is 120 g. Fig.12 It can be found that the thickness attenuation value in the adsorption stage increases with the increase of particle size. That is to say, under the same oil drop volume, the larger the particle size, the greater the thickness attenuation value. Since the thickness is calculated according to formula (3), the grayscale is linearly related to the oil film thickness, so the degree of grayscale change also increases with the increase of particle size.

[0139] To ensure the accuracy of the test law, the amount of oil dripping was increased to 120g, and it was found that the initial thickness values ​​of each particle size group were not much different. The thickness change rate of each particle size during the adsorption stage first increased, then slowed down, and finally gradually stabilized. This proves that the change of the pebble during the adsorption stage is related to the equivalent particle size of the pebble.

[0140] In order to better meet the actual research, find out the law of adsorption at the boundary of pebbles with uniform and non-uniform particle sizes, and derive the equivalent particle size formula according to the proportion of each particle size:

[0141]

[0142] Among them, d e is the equivalent particle size; d i is the actual particle size of the pebble; r i is the particle size d i The proportion of pebbles of different sizes; n is the number of types of pebbles of different sizes.

[0143] Four working conditions were set up in this oil spill test, each for a different oil drop. In order to explore whether the change in adsorption of each pebble particle size under each working condition is related to whether the pebble is a uniform particle size group or an equivalent particle size. The changes in adsorption of uniform and non-uniform pebbles over time under the same oil drop were summarized. It was found that according to the concept of equivalent particle size, the initial adsorption and stable adsorption of the pebble are proportional to the equivalent particle size.

[0144] In order to more clearly observe the effect of each particle size group on the adsorption capacity, the stable adsorption capacity of the equivalent particle size under each working condition was statistically analyzed, such as Fig.13 As shown. Fig.13 It can be found that the stable adsorption amount under each working condition increases with the increase of equivalent particle size, showing a positive proportional phenomenon. And with the increase of oil spill, the stable adsorption amount under the same equivalent particle size will also increase. This is because the increase of equivalent particle size means that the porosity of the pebbles in this particle size group increases, and the gaps inside the pebble boundary can adhere to more oil spill. And because the oil film has viscosity and hydrophobicity, the oil film inside the pebble pores will involve part of the oil film to gather inside the pores.

[0145] In order to explore the effect of the change of equivalent particle size on the adsorption per unit length of the pebble boundary, the stable adsorption per unit length under four oil drop amounts was statistically analyzed, such as Fig.14 As shown. Fig.14 It can be seen that when the oil drop amount is 60g, the equivalent particle size of the pebble is 1cm, and the adsorption per unit length is about 0.16g / cm; when the equivalent particle size of the pebble is 8cm, the adsorption per unit length reaches about 0.3g / cm. It can be found that when the equivalent particle size of the pebble is a constant, the adsorption per unit length of the pebble increases with the increase of the oil spill amount. When the oil drop amount is a constant, the adsorption per unit length of the pebble increases with the increase of the equivalent particle size, showing a positive correlation phenomenon.

[0146] According to the statistical adsorption data of each working condition, the empirical relationship between adsorption amount and time is fitted. Combined with the concept of equivalent particle size, the relationship between adsorption amount and time can be obtained, that is, the calculation formula for the adsorption amount of the pebble riverbank boundary per unit length at a certain moment is:

[0147]

[0148] Among them, M A is the amount of oil spill adsorbed by the pebble boundary per unit length; M0 is the mass of the generalized unit oil spill body; t is the total adsorption time of the pebble; t0 is the stable adsorption time; α, β, k are the adsorption coefficients related to the equivalent particle size of the river pebbles.

[0149] Step 5: Based on the equivalent particle size of river pebbles, calculate the oil spill adsorption amount at the river pebble boundary

[0150] In order to study the specific relationship between α, β, k, t0 and equivalent particle size, the specific parameter values ​​of each particle size group are statistically shown in Table 5.

[0151] Table 5 Parameter values ​​of each particle size group

[0152]

[0153] Fit the equivalent particle size and various parameters, such as Fig.15It can be clearly found that each parameter has a linear relationship with the equivalent particle size, and its coefficient of determination R 2 are 0.9605, 0.9557, 0.9556, and 0.9532, respectively, proving that the equivalent particle size d e The parameters fit well.

[0154] The fitting relationship of each parameter is now sorted out, as shown in Table 6 below.

[0155] Table 6 Fitting equations of various parameters

[0156]

[0157]

[0158] By extending formula (10) to the actual pebble riverbank, we can obtain the calculation formula for the cumulative adsorption amount at the actual pebble boundary:

[0159]

[0160] Among them, M R is the amount of oil spill adsorbed by the river pebble boundary; M0 is the unit generalized oil spill mass at a certain moment; t is the total pebble adsorption time; l is the actual river pebble boundary adsorption length; α, β, k are the adsorption coefficients corresponding to the equivalent particle size of the river pebbles. In this embodiment, α=0.0188d e +0.0338; β=-0.0193d e -0.0216; k = 0.1674d e +1.3083; t0=13.419d e +225.29.

[0161] Finally, this embodiment also proposes a system for calculating the amount of oil spill adsorption at the river pebble boundary for implementing the above calculation method, the system comprising:

[0162] The calculation model building module is used to calibrate the grayscale-thickness relationship of the oil film through the pebble boundary oil spill adsorption test and establish the grayscale-thickness calculation model of the oil film of the target oil product;

[0163] The oil film grayscale image acquisition module is used to obtain the oil film grayscale image after grayscale processing of the acquired oil spill adsorption image of the target oil product in the monitored area;

[0164] The first calculation module is used to calculate the image grayscale of the oil film grayscale image and obtain the oil film thickness of the target oil product according to the oil film grayscale-thickness calculation model;

[0165] The second calculation module is used to calculate the adsorption amount of the pebble riverbank boundary per unit length and the unit generalized oil spill mass at a certain moment according to the oil film thickness;

[0166] The third calculation module is used to calculate the oil spill adsorption amount at the river pebble boundary based on the equivalent particle size of the river pebble.

[0167] In summary, the present invention first calibrates the grayscale-thickness relationship of the oil film based on the pebble boundary oil spill adsorption test, and establishes an oil film grayscale-thickness calculation model for the target oil product; obtains the oil spill adsorption image of the target oil product in the monitored area, and performs grayscale processing to obtain the oil film grayscale image; then calculates the image grayscale of the oil film grayscale image, and obtains the oil film thickness of the target oil product according to the oil film grayscale-thickness calculation model; then calculates the adsorption amount of the pebble riverbank boundary per unit length at a certain moment and the unit generalized oil spill body mass according to the oil film thickness; finally, based on the equivalent particle size of the river pebbles, the oil spill adsorption amount of the river pebble boundary is calculated. By using the grayscale of the oil film grayscale image as the intermediate value, on the one hand, the oil film image after image grayscale processing can well highlight the oil film area and can weaken the spectral reflection of water quality, so that the method can well avoid the limitation of water quality and improve the versatility of oil film thickness detection; on the other hand, the oil film image after image grayscale processing has less information, which can greatly simplify the calculation process, so that the detection efficiency of oil film thickness can be improved under the premise of improving the versatility of detection; at the same time, the applicant found in the experiment that the grayscale of the oil film grayscale image has a good correlation with the oil film thickness, which ensures the detection accuracy of the oil film thickness and the amount of oil spill adsorption. In addition, the calculation method of the river pebble boundary oil spill adsorption based on the pebble boundary oil spill adsorption test can take into account the versatility and efficiency of oil film thickness detection, and can ensure the calculation accuracy of the oil spill adsorption.

[0168] Finally, it should be noted that the above description is only a preferred embodiment of the present invention. Under the guidance of the present invention, ordinary technicians in this field can make various similar expressions without violating the purpose and claims of the present invention, and such changes all fall within the scope of protection of the present invention.

Claims

1. A method for calculating the amount of oil spill adsorption at a river pebble boundary, characterized in that: The steps include: Step 1: calibrate the grayscale-thickness relationship of the oil film based on the pebble boundary oil spill adsorption test, and establish an oil film grayscale-thickness calculation model for the target oil product; Step 2: Obtain an oil spill adsorption image of the target oil product in the area to be monitored, and perform grayscale processing to obtain an oil film grayscale image; Step 3, calculating the image grayscale of the oil film grayscale image, and obtaining the oil film thickness of the target oil product according to the oil film grayscale-thickness calculation model; Step 4, according to the oil film thickness, the adsorption amount of the pebble riverbank boundary per unit length at a certain moment and the unit generalized oil spill mass are calculated; Step 5: Based on the equivalent particle size of river pebbles, the oil spill adsorption capacity at the river pebble boundary is calculated using the following formula: Among them, M R is the amount of oil spill adsorbed by the river pebble boundary; M0 is the unit generalized oil spill mass at a certain moment; t is the total pebble adsorption time; l is the actual river pebble boundary adsorption length; α, β, k are the adsorption coefficients corresponding to the equivalent particle size of river pebbles.

2. The method for calculating the amount of oil spill adsorption at the river pebble boundary according to claim 1, characterized in that: The expression of the oil film grayscale-thickness calculation model of the target oil product is: y=-ax+b, Among them, y is the oil film thickness; x is the oil film grayscale; a is the coefficient; b is a constant.

3. The method for calculating the amount of oil spill adsorption at the river pebble boundary according to claim 1, characterized in that: The steps for calibrating the grayscale-thickness relationship of the oil film based on the pebble boundary oil spill adsorption test in step 1 are as follows: Step 1.1, fix the test container under the camera and lay a white anti-scratch cloth under the test container; Step 1.2: Use pebbles of different or the same particle size to build a simulated river pebble boundary in a test container, and add clean water into the test container; Step 1.3, adding a dye to the target oil product in proportion to prepare a target oil product solution; Step 1.4, inject a certain mass of target oil solution into the central area of ​​the clean water in the test container; Step 1.5, using a camera to obtain an oil film image when the target oil solution expands in clean water to cover the surface of the test container, performing image grayscale processing on the oil film image and calculating the image grayscale, and at the same time calculating the corresponding oil film thickness according to the amount of oil spill; Step 1.6, repeating steps 1.2 and 1.5 for multiple times, and obtaining multiple groups of target oil solution image grayscale and corresponding oil film thickness data groups by changing the pebble particle size and oil filling amount; Step 1.7, calibrate the oil film grayscale-thickness relationship based on multiple groups of target oil image grayscales and corresponding oil film thickness data groups to obtain an oil film grayscale-thickness calculation model for the target oil.

4. The method for calculating the amount of oil spill adsorption at the river pebble boundary according to claim 3, characterized in that: The calculation formula for the corresponding oil film thickness calculated according to the oil spill volume in step 1.5 is: Among them, h t is the oil film thickness; m1 is the weight of the test container when no oil is dripped; m2 is the weight of the test container after oil is dripped; ρ is the density of the mixed hydraulic oil; s is the surface area of ​​the oil film.

5. The method for calculating the amount of oil spill adsorption at the river pebble boundary according to claim 4, characterized in that: In step 1.5, a camera is used to obtain an oil film image when the target oil solution expands in clean water to cover the surface of the test container. The process of performing image grayscale processing on the oil film image and calculating the image grayscale is as follows: A camera is used to record the entire process of the target oil solution spreading in clean water until it covers the entire surface of the test container; Smart Player video processing software is used to process the video data. In the oil film expansion stage, a video screenshot is taken at a first time interval; in the oil film adsorption stage, a video screenshot is taken at a second time interval; The image obtained by screenshot was gray-processed using ImageJ image processing software until the desired oil film gray-scale image was obtained when the image gray-scale value remained unchanged, and the image gray-scale was calculated based on the oil film gray-scale image.

6. The method for calculating the amount of oil spill adsorption at the river pebble boundary according to claim 5, characterized in that: The value of the second duration is not less than the value of the first duration.

7. The method for calculating the amount of oil spill adsorption at the river pebble boundary according to claim 1, characterized in that: In step 4, the calculation formula for the adsorption amount of the pebble riverbank boundary per unit length at a certain moment is calculated based on the oil film thickness: Among them, M A is the amount of oil spill adsorbed by the pebble boundary per unit length; M0 is the mass of the generalized unit oil spill body; t is the total adsorption time of the pebble; t0 is the stable adsorption time; α, β, k are the adsorption coefficients related to the equivalent particle size of the river pebbles.

8. The method for calculating the amount of oil spill adsorption at the river pebble boundary according to claim 1, characterized in that: The calculation formula for the unit generalized oil spill mass in step 4 is: M0=V0·ρ Where M0 is the unit oil spill mass; V0 = a·b·d t is the volume of the oil spill per unit length; a and b are the length and width of the oil spill per unit length; d t is the oil film thickness per unit oil spill; ρ is the density of the target oil.

9. The method for calculating the amount of oil spill adsorption at the river pebble boundary according to claim 1, characterized in that: The calculation formula of the equivalent particle size of the river pebbles is: Among them, d e is the equivalent particle size; d i is the actual particle size of the pebble; r i is the particle size d i The proportion of pebbles of different sizes; n is the number of types of pebbles of different sizes.

10. The method for calculating the amount of oil spill adsorption at the river pebble boundary according to any one of claims 1 to 9, characterized in that: The relationship between the adsorption coefficients α, β, k and the equivalent particle size of river pebbles is as follows: α=c1*d e +f1; β=-c2*d e +f2; k=c3*d e +f3; Among them, c1, c2, and c3 are coefficients related to equivalent particle size, d e is the equivalent particle size; f1, f2, f3 are constants.

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