Device and method for preparing and collecting asphalt fume under simulated mixing condition

Abstract

The invention relates to the technical field of asphalt smoke detection, and discloses an asphalt smoke preparation and collection device and method under simulated mixing conditions. The device comprises a reactor, a filter and a receiving bottle, the reactor comprises a heating furnace, the upper side of the heating furnace is fixedly provided with a tank body, the axis of the tank body is fixedly provided with a central shaft, the surface of the central shaft is rotatably provided with a stirrer, and the end part of the tank body is fixedly provided with a servo motor. According to the device, the arc-shaped plate in circular motion is arranged in the reactor, the arc-shaped plate not only has the function of stirring asphalt, but also has the functions of promoting external air to enter the reactor and promoting asphalt smoke in the reactor to be discharged, so that the air speed condition is omitted, and the simulated mixing condition of asphalt smoke preparation is closer to the condition of on-site asphalt smoke collection; the influence of the airspeed condition on the asphalt smoke release amount is reduced, the calculation error of the asphalt smoke mass is reduced, and the experiment accuracy is improved.

Description

Technical Field

[0001] The invention relates to the technical field of asphalt fume detection, and in particular to an asphalt fume preparation and collection device and method under simulated mixing conditions. Background Art

[0002] Asphalt is a solid or semi-solid material at room temperature. When it is used in the fields of roads, construction, waterproof materials, etc., in order to make the asphalt, aggregates and other additives mix evenly, the viscosity of the asphalt must be reduced by heating. Asphalt will produce asphalt smoke under the action of heat. Asphalt smoke is produced and released into the air, causing varying degrees of air pollution. Therefore, the effect of mixing conditions on the release and chemical composition of asphalt smoke is evaluated in the laboratory, which provides a theoretical basis for reducing the release of asphalt smoke during hot mixing or hot processing of asphalt.

[0003] In the prior art, the patent document with the announcement number CN116593648A discloses an asphalt fume detection device and evaluation method, wherein the detection device comprises a reactor; the reactor is connected with a first exhaust pipe and a second exhaust pipe; the first exhaust pipe is connected in series with a solid particle pollutant enrichment device, a sampling pump, an air bag collection device and a Suma tank collection device in the exhaust direction; the second exhaust pipe is connected in series with an inorganic gas detection device in the exhaust direction; the solid particle pollutant enrichment device is correspondingly arranged with an analytical balance for detecting the concentration and total emission of solid particle pollutants; the Suma tank collection device is correspondingly arranged with a gas chromatograph-gas spectrometer for detecting volatile organic compounds; the inorganic gas detection device is used to detect the concentration of inorganic gases. The generation of asphalt fume under different working conditions can be simulated to form a complete system integrating the generation, collection, detection and evaluation of asphalt fume, so as to realize a comprehensive analysis of asphalt fume and provide a reference for the targeted treatment of asphalt fume.

[0004] According to research, the conditions that affect the release of asphalt smoke include temperature, action time, air velocity and stirring rate (see reference: Cai Hongmei. Research on the impact of asphalt on the environment during use [D]. China University of Petroleum, 2010). The deep oxidation of asphalt is the main cause of the generation of asphalt smoke, but the size of the air velocity has a great influence on the deep oxidation of asphalt. Because the increase in air velocity increases the probability of contact between asphalt and oxygen, the degree of oxidation of asphalt increases, and then the amount of asphalt smoke produced increases. Certain air velocity conditions are required in the experimental environment to help collect asphalt smoke. There is no specific air velocity condition for collecting asphalt smoke on site. There is a big difference between collecting asphalt smoke in the experimental environment and on site, resulting in a large error in the calculation of the asphalt smoke release. Based on this, the existing asphalt smoke preparation and collection device has the problem of inaccurate collection of asphalt smoke, which needs to be further improved. Summary of the invention

[0005] The purpose of the present invention is to solve the defect of inaccurate collection of asphalt fumes in the prior art by the asphalt fume preparation and collection device, and to propose an asphalt fume preparation and collection device and method under simulated mixing conditions.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an asphalt smoke preparation and collection device under simulated mixing conditions, comprising a reactor, a filter and a receiving bottle, the reactor comprising a heating furnace, a tank body is fixedly installed on the upper side of the heating furnace, a central axis is fixedly installed at the axis of the tank body, an agitator is rotatably installed on the surface of the central axis, a servo motor is fixedly installed at the end of the tank body, the servo motor drives the agitator to rotate, an input pipe and an output pipe are respectively installed at both ends of the tank body, the tank body is connected to the filter through the output pipe, an air inlet pipe and an air outlet pipe are respectively fixedly installed at the mouth of the receiving bottle, and the receiving bottle is connected to the filter through the air inlet pipe.

[0007] Preferably, the tank body is arranged horizontally on the upper side of the heating furnace, a feeding port is arranged on the upper side of the tank body, and a sealing cover is threadedly installed on the feeding port, the agitator includes a rotating sleeve and an arc plate, the rotating sleeve is rotatably sleeved on the surface of the central axis, the end of the rotating sleeve is fixedly connected to the rotating end of the servo motor, one side of the arc plate is fixedly connected to the rotating sleeve, and the side of the arc plate away from the rotating sleeve is in sliding contact with the inner wall of the tank body.

[0008] Preferably, an air inlet window and an air outlet window are respectively provided on the inner walls at both ends of the tank body, the input pipe is connected to the air inlet window, the output pipe is connected to the air outlet window, the two ends of the arc plate are respectively in sliding contact with the inner side walls at both ends of the tank body, and during the rotation of the arc plate, the inner arc surface of the arc plate and the upper surface of the material in the tank body form an air cavity with a changing inner cavity volume, and the air cavity with a changing inner cavity volume is connected to the air outlet window.

[0009] Preferably, one end of the central shaft extends to the outside of the tank body, a temperature sensor is fixedly installed at the end of the central shaft, the detection head of the temperature sensor is embedded in the surface of the central shaft, an open groove is provided on the surface of the rotating sleeve, and the detection head of the temperature sensor contacts the material in the tank body through the open groove.

[0010] Preferably, there are two filters, which are connected in series, and a detachable glass fiber filter cartridge is disposed inside the two filters.

[0011] The present invention also proposes a method for preparing and collecting asphalt smoke under simulated mixing conditions, comprising the following steps:

[0012] Step 1: Place the glass fiber filter cartridge in a 105°C oven for 2 hours to remove the moisture in the cartridge, then take it out and place it in a dryer for later use;

[0013] Step 2: Remove the sealing cover, pour 500 g ± 10 g of the asphalt sample M that has been preheated to fluidity into the tank, accurate to 0.1 g, close the feeding port, weigh the mass M1 of the two glass fiber filter cartridges treated in step 1, accurate to 0.001 g, and install the two glass fiber filter cartridges into the two filters respectively, and check the air tightness at the same time;

[0014] Step 3: Pour 300 mL of analytically pure cyclohexane into the receiving bottle to dissolve it, cover the bottle with a stopper, and connect the air inlet and outlet pipes;

[0015] Step 4: Turn on the heating furnace, set the temperature to 163°C, and the speed of the servo motor to 15r / min. After the temperature is constant, open the constant pressure valve and collect the asphalt smoke for 2 hours;

[0016] Step 5: After the test is completed, remove the filter, take out the two glass fiber filter cartridges, place them in a dryer for 72 hours, and weigh M2. The difference in mass between the two weighings is the amount of the collected particulate asphalt smoke component M weight = (M2-M1) × 1000, in mg;

[0017] Step 6: evaporate and concentrate the cyclohexane solution in the receiving bottle and calibrate it to 100 ml. Take 1 ml into a 50 ml colorimetric tube and calibrate it to the 50 ml mark with cyclohexane for UV analysis (the concentration range of asphalt smoke is 0-50 μg / mL at this time). The absorbance X is tested at a wavelength of 227 nm, and the concentration of asphalt smoke is calculated by the formula Y=0.02242+0.03012X. The mass of the asphalt smoke Mlight=Y×5 is calculated by conversion, and the unit is mg.

[0018] Step 7: Add the masses Mheavy and Mlight of the asphalt fumes obtained in step 5 and step 6 to obtain the total amount of collected asphalt fumes and then divide it by the amount of asphalt. Finally, the amount of asphalt fumes is expressed in mg / kg, that is:

[0019] By using the asphalt fume preparation and collection device under simulated mixing conditions and the asphalt fume preparation and collection method under simulated mixing conditions proposed by the present invention, a conversion relationship between temperature and time in the field simulation process is established, and the conversion formula is:

[0020] in,

[0021] T-temperature, temperature range: 163℃~200℃;

[0022] t-time, unit: hour;

[0023] The penetration value of asphalt after PT-TFOT;

[0024] P0-needle penetration value of base asphalt.

[0025] The present invention has the following beneficial effects:

[0026] 1. The asphalt fume preparation and collection device proposed in the present invention has an arc plate that moves in a circular motion in the reactor. The arc plate not only has the function of stirring the asphalt, but also has the function of prompting the outside air to enter the reactor and prompting the asphalt fume in the reactor to be discharged. The air velocity condition is omitted, so that the simulated mixing conditions for asphalt fume preparation are closer to the conditions for collecting asphalt fume on site, the influence of the air velocity condition on the release amount of asphalt fume is reduced, the calculation error of the asphalt fume quality is reduced, and the accuracy of the experiment is improved.

[0027] 2. By setting a central axis at the axis center of the tank body, the detection head of the temperature sensor is embedded in the surface of the central axis. When the arc plate rotates, the side of the arc plate away from the central axis can scrape the asphalt inside the tank body to ensure uniform mixing of the asphalt and avoid local overheating of the asphalt attached to the inner wall to accelerate decomposition. The inner arc surface of the arc plate can push the asphalt in the tank to flow through the detection head of the temperature sensor, making the asphalt temperature measured by the temperature sensor more accurate. The asphalt smoke quality detected by the asphalt smoke preparation and collection device is accurately related to the temperature, which also provides reliable experimental data for establishing a conversion relationship between temperature and time in a field simulation process.

[0028] 3. The asphalt fume preparation and collection method proposed in the present invention eliminates the condition of controlling the air velocity. The conditions that affect the release of asphalt fume are only temperature, action time and stirring rate. The use of the asphalt fume preparation and collection device can accurately control the temperature and stirring rate. The contact between air and asphalt is determined by the stirring rate. A certain stirring rate can ensure a stable air input amount, and can effectively avoid the increase in air velocity under simulated conditions, which increases the probability of contact between asphalt and oxygen, resulting in an increase in the degree of oxidation of asphalt, and then increases the amount of asphalt fume produced, affecting the release of asphalt fume, so that the asphalt fume preparation and collection method can more accurately simulate the on-site asphalt mixing environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the planar structure of the asphalt fume preparation and collection device proposed by the present invention;

[0030] Figure 2 This is a schematic diagram of the three-dimensional structure of the reactor proposed by the present invention (I);

[0031] Figure 3 This is a schematic diagram of the three-dimensional structure of the reactor proposed by the present invention (II);

[0032] Figure 4 This is a schematic diagram of the side cross-sectional structure of the reactor proposed by the present invention (I);

[0033] Figure 5This is a schematic diagram of the central axis side section structure proposed by the present invention;

[0034] Figure 6 This is a schematic diagram of the side cross-sectional structure of the reactor proposed in the present invention (II).

[0035] In the figure: 1 filter, 2 receiving bottle, 3 heating furnace, 4 tank body, 5 central axis, 6 servo motor, 7 input pipe, 8 output pipe, 9 air inlet pipe, 10 air outlet pipe, 11 sealing cover, 12 rotating sleeve, 13 arc plate, 14 air inlet window, 15 air outlet window, 16 temperature sensor, 17 opening slot, 18 glass fiber filter cartridge, 19 compressed gas cylinder, 20 constant pressure valve. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0037] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0038] refer to Figure 1-6 The present invention proposes an asphalt smoke preparation and collection device under simulated mixing conditions, including a reactor, a filter 1 and a receiving bottle 2. The reactor includes a heating furnace 3. A tank body 4 is fixedly installed on the upper side of the heating furnace 3. A central shaft 5 is fixedly installed at the axis of the tank body 4. A stirrer is rotatably installed on the surface of the central shaft 5. A servo motor 6 is fixedly installed at the end of the tank body 4. The servo motor 6 drives the stirrer to rotate. An input pipe 7 and an output pipe 8 are respectively installed at both ends of the tank body 4. The tank body 4 is connected to the filter 1 through the output pipe 8. An air inlet pipe 9 and an air outlet pipe 10 are respectively fixedly installed at the mouth of the receiving bottle 2. The receiving bottle 2 is connected to the filter 1 through the air inlet pipe 9. There are two filters 1, and the two filters 1 are connected in series. A detachable glass fiber filter cartridge 18 is arranged inside the two filters 1.

[0039] Specifically, the tank body 4 is arranged horizontally on the upper side of the heating furnace 3, a feeding port is arranged on the upper side of the tank body 4, and a sealing cover 11 is threadedly installed on the feeding port. The tank body 4 can be made of glass or stainless steel. The ratio of the bottom diameter R and the height L of the tank body 4 should be controlled in the range of 1:2.2-1:2.5. The tank body 4 can be enlarged or reduced according to actual needs, and the amount of asphalt is adjusted according to the volume of the tank body 4.

[0040] The agitator includes a rotating sleeve 12 and an arc plate 13. The rotating sleeve 12 is rotatably mounted on the surface of the central shaft 5. The end of the rotating sleeve 12 is fixedly connected to the rotating end of the servo motor 6. One side of the arc plate 13 is fixedly connected to the rotating sleeve 12. The side of the arc plate 13 away from the rotating sleeve 12 is in sliding contact with the inner wall of the tank body 4.

[0041] refer to Figure 2 , Figure 3 The inner walls at both ends of the tank body 4 are respectively provided with an air inlet window 14 and an air outlet window 15, the input pipe 7 is connected to the air inlet window 14, the output pipe 8 is connected to the air outlet window 15, the two ends of the arc plate 13 are respectively in sliding contact with the inner side walls at both ends of the tank body 4, and during the rotation of the arc plate 13, the inner arc surface of the arc plate 13 and the upper surface of the material in the tank body 4 form an air cavity with a changing inner cavity volume, and the air cavity with a changing inner cavity volume is connected to the air outlet window 15, refer to Figure 4 .

[0042] One end of the central shaft 5 extends to the outside of the tank body 4, and a temperature sensor 16 is fixedly installed at the end of the central shaft 5. The detection head of the temperature sensor 16 is embedded in the surface of the central shaft 5. An opening groove 17 is opened on the surface of the rotating sleeve 12. The detection head of the temperature sensor 16 contacts the material in the tank body 4 through the opening groove 17. Figure 5 .

[0043] In this embodiment, the end of the input pipe 7 away from the tank body 4 is connected to a compressed gas cylinder 19, and a constant pressure valve 20 is provided on the input pipe 7. It should be noted that the compressed gas cylinder 19 is provided to ensure the safety of the laboratory environment and prevent the backflow and overflow of asphalt smoke, rather than continuously injecting air into the tank body 4 to cause the asphalt smoke to enter the receiving bottle. Under the action of the constant pressure valve 20, when the pressure in the tank body 4 drops, the constant pressure valve 20 automatically opens, and the air in the compressed gas cylinder 19 passes through the constant pressure valve 20 into the tank body 4. When the air pressure in the tank body 4 is within a preset range, the constant pressure valve 20 is closed.

[0044] During use, preheated asphalt is added into the tank body 4, and the asphalt liquid level submerges the lower side of the central axis 5. Figure 4 As shown by the horizontal dotted line in the middle, when the servo motor 6 drives the arc plate 13 to rotate counterclockwise with the central axis 5 as the axis, the air on one side of the inner arc surface of the arc plate 13 is compressed (it should be noted that the surface of the arc plate 13 is attached with asphalt liquid, which plays a good sealing role and can effectively prevent the compressed air inside from leaking), and is discharged from the output pipe 8, that is, the air and asphalt smoke in the air cavity with the changed inner cavity volume are transported from the output pipe 8 to the filter 1 and the receiving bottle 2. The glass fiber filter cartridges 18 in the two series-connected filters 1 mainly collect the granular asphalt smoke components with a particle size greater than 3um, and the receiving bottle 2 filled with cyclohexane solution mainly collects the granular components with a particle size less than 3um and other gas components;

[0045] At the same time, when the arc plate 13 rotates, the asphalt liquid enters the inner arc cavity of the arc plate 13, as shown in FIG. Figure 6 As shown, the asphalt liquid in the arc plate 13 flows through the detection head of the temperature sensor 16, which improves the accuracy of asphalt temperature measurement. The side of the arc plate 13 away from the central axis 5 can scrape the asphalt inside the tank 4 to ensure uniform mixing of the asphalt and avoid the asphalt attached to the inner wall from being locally overheated and accelerating decomposition;

[0046] like Figure 6 As shown, the arc plate 13 continues to rotate. At this time, the air pressure on the right side of the arc plate 13 decreases, the constant pressure valve 20 automatically opens, and the air in the compressed gas cylinder 19 passes through the constant pressure valve 20 and enters the tank body 4. This design enables the asphalt smoke in the tank body 4 to be discharged in time, and the air to be replenished in the tank body 4 in time.

[0047] The asphalt fume preparation and collection device proposed in the present invention has an arc plate 13 that moves in a circular motion arranged in the reactor. The arc plate 13 not only has the function of stirring the asphalt, but also has the function of prompting the outside air to enter the reactor and prompting the asphalt fume in the reactor to be discharged. The air velocity condition is eliminated, so that the simulated mixing conditions for asphalt fume preparation are closer to the conditions for collecting asphalt fume on site, the influence of the air velocity condition on the release amount of asphalt fume is reduced, the calculation error of the asphalt fume quality is reduced, and the accuracy of the experiment is improved.

[0048] The present invention also proposes a method for preparing and collecting asphalt smoke under simulated mixing conditions, comprising the following steps:

[0049] Step 1: Place the glass fiber filter cartridge 18 in a 105°C oven for 2 hours to remove moisture from the glass fiber filter cartridge 18, then take it out and place it in a dryer for later use;

[0050] Step 2, remove the sealing cover 11, pour 500g±10g of the asphalt sample M that has been preheated to fluidity into the tank body 4, accurate to 0.1g, close the feeding port, weigh the mass M1 of the two glass fiber filter cartridges 18 processed in step 1, accurate to 0.001g, and install the two glass fiber filter cartridges 18 into the two filters 1 respectively, and check the air tightness at the same time;

[0051] Step 3: Pour 300 mL of analytically pure cyclohexane into the receiving bottle 2 to dissolve, cover the bottle with a stopper, connect the air inlet pipe 9 and the air outlet pipe 10, and Figure 1 Connect each device as shown;

[0052] Step 4, start the heating furnace 3, set the temperature to 163°C, the speed of the servo motor 6 to 15r / min, and after the temperature is constant, open the constant pressure valve 20, and collect the asphalt smoke for 2h;

[0053] Step 5: After the test is completed, remove the filter 1, take out the two glass fiber filter cartridges 18, place them in a dryer for 72 hours, and then weigh M2. The difference in mass between the two weighings is the amount of the collected particulate asphalt smoke component M weight = (M2-M1) × 1000, in mg;

[0054] Step 6, evaporate and concentrate the cyclohexane solution in the receiving bottle 2 and calibrate it to 100 ml, take 1 ml into a 50 ml colorimetric tube, calibrate it to the 50 ml mark with cyclohexane, and then perform ultraviolet analysis (the concentration range of asphalt smoke is 0-50 μg / mL at this time), and calculate the concentration of asphalt smoke by the formula Y=0.02242+0.03012X at a wavelength of 227 nm, and then calculate the mass of asphalt smoke Mlight=Y×5 by conversion, in mg;

[0055] Step 7: Add the masses Mheavy and Mlight of the asphalt fumes obtained in step 5 and step 6 to obtain the total amount of collected asphalt fumes and then divide it by the amount of asphalt. Finally, the amount of asphalt fumes is expressed in mg / kg, that is:

[0056] During the on-site mixing process, asphalt materials will change due to the influence of external factors such as temperature. This process is also called the aging process. At present, the tests used in my country to evaluate the aging process of asphalt are "Petroleum Asphalt Thin Film Oven Test Method" (GB / T 5304-2001) and "Asphalt Thin Film Heating Test" (JTG E20-2011 T0609-2011). Both test methods are process methods, and the principles and steps are the same, which are equivalent. At present, based on the research of a large number of scholars, it is generally recognized that the asphalt aging process is the process of migration and change of asphalt components. That is to say, the change of components can be used to characterize the degree of asphalt aging. At present, the methods for evaluating the four components of asphalt are "Petroleum Asphalt Four Component Determination Method" (NB / SH / T0509-2010) and "Asphalt Chemical Composition Test (JTG E20-2011 T0618-2011)". These two standard methods and principles are also the same and equivalent. Therefore, the test example of the present invention uses the "Petroleum Asphalt Thin Film Oven Test Method" (GB / T5304-2001) as the aging process test, and the four-component results obtained by the "Petroleum Asphalt Four-Component Determination Method" (NB / SH / T 0509-2010) are used as the basis for judgment to evaluate the effectiveness of the asphalt smoke preparation and collection device and method used in the present invention.

[0057] Example 1

[0058] Weigh 500g of 90# asphalt sample and prepare asphalt smoke according to the above method. After the preparation, the asphalt sample is analyzed for four components and compared with the four components of the base asphalt after the "Petroleum Asphalt Thin Film Oven Test Method" (GB / T 5304-2001) (TFOT test for short). The results are shown in Table 1. From the distribution of the four components in Table 1, it can be seen that the four components of the asphalt obtained under the conditions of the present invention are relatively close to the four components of the asphalt after the TFOT test, and the test results are all within the error tolerance range. In order to further verify the effectiveness of the process of the present invention, the three major performance indicators of the asphalt after aging are tested. The results are shown in Table 2. From the data in Table 2, it can be seen that the indicators of the asphalt obtained in this embodiment are also relatively close to the indicators after the TFOT test, which shows that the aging process of the asphalt under the conditions of the present invention is equivalent to the aging process of the TFOT test, which can characterize the aging situation in the asphalt mixing process, and also shows that the asphalt smoke obtained under the conditions of the present invention can simulate the asphalt smoke released under the mixing conditions.

[0059] Table 190# Asphalt Four Component Distribution

[0060]

[0061] Table 2 Three indicators of 90# asphalt under simulated mixing conditions

[0062]

[0063] Example 2

[0064] Weigh 500g of 70# asphalt and carry out the test according to the method and steps of the present invention, and the test results are shown in Tables 3 and 4. From the comparison of the four component data in Table 3, it can be seen that the four components of the asphalt under the conditions of the present invention are relatively close to the four components after the TFOT test, and the three major performance indicators of the asphalt in Table 4 are also relatively close, basically within the test allowable error range, which shows that the test method of the present invention is also applicable to 70# asphalt.

[0065] Table 370# Asphalt Four Component Distribution

[0066]

[0067] Table 4 Three indicators of 70# asphalt under simulated mixing conditions

[0068]

[0069] The asphalt fume preparation and collection method proposed in the present invention eliminates the condition of controlling the air velocity. The conditions that affect the amount of asphalt fume released are only temperature, action time and stirring rate. The use of the asphalt fume preparation and collection device can accurately control the temperature and stirring rate. The contact between air and asphalt is determined by the stirring rate. A constant stirring rate can ensure a stable air input amount, and can effectively avoid the increase in air velocity under simulated conditions, which increases the probability of contact between asphalt and oxygen, resulting in an increase in the degree of oxidation of asphalt, and then increases the amount of asphalt fume generated, affecting the release of asphalt fume, so that the asphalt fume preparation and collection method can more accurately simulate the on-site asphalt mixing environment.

[0070] The present invention also provides a method for converting the preparation time and temperature of asphalt fume under simulated on-site mixing conditions. By using an asphalt fume preparation and collection device under simulated mixing conditions and an asphalt fume preparation and collection method under simulated mixing conditions proposed by the present invention, a conversion relationship between temperature and time in an on-site simulation process is established. For an asphalt material, the time used to prepare asphalt fume under different temperatures under simulated mixing conditions can be calculated based on the needle penetration value after TFOT aging. The conversion formula is:

[0071] in,

[0072] T-temperature, temperature range: 163℃~200℃;

[0073] t-time, unit: hour;

[0074] The penetration value of asphalt after PT-TFOT;

[0075] P0-needle penetration value of base asphalt.

[0076] It can be seen from the above conversion formula that the control and measurement accuracy of temperature T directly affects the accuracy of the time t used to prepare asphalt smoke. By setting a central axis 5 at the axis of the tank body 4, the detection head of the temperature sensor 16 is embedded in the surface of the central axis 5. When the arc plate 13 rotates, the side of the arc plate 13 away from the central axis 5 can scrape the asphalt inside the tank body 4 to ensure uniform stirring of the asphalt and avoid local overheating of the asphalt attached to the inner wall, which accelerates the decomposition of the asphalt. In addition, the inner arc surface of the arc plate 13 can push the asphalt in the tank to flow through the detection head of the temperature sensor 16, so that the asphalt temperature measured by the temperature sensor 16 is more accurate. The asphalt smoke quality detected by the asphalt smoke preparation and collection device is accurately related to the temperature, which also provides reliable experimental data for establishing a conversion relationship between temperature and time in a field simulation process.

[0077] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A device for preparing and collecting asphalt smoke under simulated mixing conditions, comprising a reactor, a filter (1) and a receiving bottle (2), characterized in that: The reactor comprises a heating furnace (3), a tank body (4) is fixedly mounted on the upper side of the heating furnace (3), a central shaft (5) is fixedly mounted at the axis of the tank body (4), a stirrer is rotatably mounted on the surface of the central shaft (5), a servo motor (6) is fixedly mounted at the end of the tank body (4), the servo motor (6) drives the stirrer to rotate, an input pipe (7) and an output pipe (8) are respectively mounted at both ends of the tank body (4), the tank body (4) is connected to the filter (1) via the output pipe (8), an air inlet pipe (9) and an air outlet pipe (10) are respectively fixedly mounted at the mouth of the receiving bottle (2), and the receiving bottle (2) is connected to the filter (1) via the air inlet pipe (9).

2. The asphalt fume preparation and collection device under simulated mixing conditions according to claim 1, characterized in that: The tank body (4) is arranged transversely on the upper side of the heating furnace (3), a feeding port is arranged on the upper side of the tank body (4), and a sealing cover (11) is threadedly installed on the feeding port, the agitator comprises a rotating sleeve (12) and an arc plate (13), the rotating sleeve (12) is rotatably sleeved on the surface of the central shaft (5), the end of the rotating sleeve (12) is fixedly connected to the rotating end of the servo motor (6), one side of the arc plate (13) is fixedly connected to the rotating sleeve (12), and the side of the arc plate (13) away from the rotating sleeve (12) is in sliding contact with the inner wall of the tank body (4).

3. The asphalt fume preparation and collection device under simulated mixing conditions according to claim 2, characterized in that: An air inlet window (14) and an air outlet window (15) are respectively provided on the inner walls at both ends of the tank body (4); the input pipe (7) is connected to the air inlet window (14); the output pipe (8) is connected to the air outlet window (15); the two ends of the arc plate (13) are respectively in sliding contact with the inner side walls at both ends of the tank body (4); during the rotation of the arc plate (13), the inner arc surface of the arc plate (13) and the upper surface of the material in the tank body (4) form an air cavity with a changing inner cavity volume; the air cavity with a changing inner cavity volume is connected to the air outlet window (15).

4. The asphalt fume preparation and collection device under simulated mixing conditions according to claim 3, characterized in that: One end of the central shaft (5) extends to the outside of the tank body (4); a temperature sensor (16) is fixedly mounted on the end of the central shaft (5); a detection head of the temperature sensor (16) is embedded in the surface of the central shaft (5); an open groove (17) is provided on the surface of the rotating sleeve (12); and the detection head of the temperature sensor (16) contacts the material in the tank body (4) through the open groove (17).

5. The asphalt fume preparation and collection device under simulated mixing conditions according to claim 4, characterized in that: There are two filters (1), which are connected in series, and a detachable glass fiber filter cartridge (18) is arranged inside the two filters (1).

6. The asphalt fume preparation and collection device under simulated mixing conditions according to claim 5, characterized in that: One end of the input pipe (7) away from the tank body (4) is connected to a compressed gas cylinder (19), and a constant pressure valve (20) is provided on the input pipe (7).

7. A method for preparing and collecting asphalt smoke under simulated mixing conditions, characterized in that: The following steps are involved: Step 1: Place the glass fiber filter cartridge (18) in a 105°C oven for 2 hours to remove moisture from the filter cartridge, then place it in a dryer for later use; Step 2: remove the sealing cover (11), pour 500 g ± 10 g of the asphalt sample M that has been preheated to fluidity into the tank body (4), accurate to 0.1 g, close the feeding port, weigh the mass M1 of the two glass fiber filter cartridges (18) treated in step 1, accurate to 0.001 g, and install the two glass fiber filter cartridges (18) into the two filters (1) respectively, and check the air tightness at the same time; Step 3: Pour 300 mL of analytically pure cyclohexane into the receiving bottle (2) to dissolve, cover the bottle with a stopper, and connect the air inlet pipe (9) and the air outlet pipe (10); Step 4: start the heating furnace (3), set the temperature to 163°C, the speed of the servo motor (6) to 15r / min, and after the temperature is constant, open the constant pressure valve (20) and collect the asphalt smoke for 2 hours; Step 5: After the test is completed, remove the filter (1), take out the two glass fiber filter cartridges (18), place them in a dryer for 72 hours, and then weigh M2. The difference in mass between the two weighings is the amount of the collected particulate asphalt smoke component M weight = (M2-M1) × 1000, in mg; Step 6, evaporate and concentrate the cyclohexane solution in the receiving bottle (2) and calibrate it to 100 ml, take 1 ml into a 50 ml colorimetric tube, calibrate it to the 50 ml mark with cyclohexane, and then perform ultraviolet analysis (the concentration range of asphalt smoke is 0-50 μg / mL at this time), and calculate the concentration of asphalt smoke by the formula Y=0.02242+0.03012X at a wavelength of 227 nm, and then calculate the mass of asphalt smoke Mlight=Y×5 by conversion, in mg; Step 7: Add the masses Mheavy and Mlight of the asphalt fumes obtained in step 5 and step 6 to obtain the total amount of collected asphalt fumes and then divide it by the amount of asphalt. Finally, the amount of asphalt fumes is expressed in mg / kg, that is:

8. A method for converting the preparation time and temperature of asphalt fume under simulated on-site mixing conditions, applied to the asphalt fume preparation and collection device under simulated mixing conditions described in any one of claims 1 to 5 and the asphalt fume preparation and collection method under simulated mixing conditions described in claim 7, to establish a conversion relationship between temperature and time during the on-site simulation process, and the conversion formula is: in, T-temperature, temperature range: 163℃~200℃; t-time, unit: hour; PT-penetration value of asphalt after TFOT; P0-penetration value of base asphalt.

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