Rapid evaluation method for guiding asphalt polymerization reaction degree control

Abstract

The invention discloses a rapid evaluation method for guiding asphalt polymerization reaction degree control, which comprises the following steps of: evaluating a softening point, a coking value and a change relation of viscosity along with polymerization time in an asphalt raw material polymerization process in advance, making a relation curve graph, and only monitoring an asphalt viscosity index which is simple and rapid in analysis process in a production process. And the reaction endpoint is judged by utilizing the relation curve to backtrack the softening point and the coking value, so that the control of the asphalt polymerization production process is efficiently guided. The method is simple and easy to implement, time-saving and labor-saving, long-time index analysis is omitted, rapid feedback is performed on production regulation and control, the production regulation and control frequency can be reduced, the production efficiency can be improved, and meanwhile product index accurate control and batch product quality stability and consistency are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of modified asphalt production, and in particular to a rapid evaluation method for guiding the control of asphalt polymerization reaction degree. Background Art

[0002] Modified asphalt is a product produced by modifying ordinary asphalt to meet specific application requirements. This modified asphalt can be processed into high-performance products such as carbon fiber and mesophase asphalt, or used to modify carbon products, such as coated asphalt. The former achieves high-value-added utilization of asphalt, while the latter effectively reduces the number of surface defects and improves the material's recyclability and rate performance.

[0003] Softening point, coking value, and viscosity are important quality indicators of asphalt. The softening point and coking value indirectly reflect the distribution of the asphalt's molecular composition. Generally, low coking values ​​and softening points indicate a high concentration of small molecules, while high softening points and coking values ​​indicate a high concentration of medium and large molecules. Viscosity is the external manifestation of the sliding friction generated by the internal movement of molecules, creating flow resistance. It is closely related to molecular composition. During the asphalt polymerization modification process, as the degree of polymerization increases, the number of large molecules increases, and the intermolecular viscous forces increase, resulting in an increase in viscosity. Therefore, under certain conditions, there is a certain correspondence between the viscosity of asphalt and the softening point and coking value. This correspondence can be used to guide the control of the asphalt modification process.

[0004] The two most mature industrially used methods for preparing modified asphalt include polymerization and flash distillation. To enhance the performance of asphalt, polymerization can intrinsically improve performance indicators at the molecular level and is the most commonly used method in the industry. However, in actual production, there is no particularly effective method for precisely controlling the polymerization reaction. Softening point and coking value tests are typically performed to monitor the degree of polymerization and determine the discharge time. However, coking value tests are time-consuming, requiring at least three hours from sampling to results, and cannot provide a quick assessment of the actual degree of polymerization. Dynamic viscosity constant-temperature testing, on the other hand, only takes three to five minutes. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a rapid evaluation method for guiding the control of the degree of asphalt polymerization reaction, which eliminates the time-consuming indicator analysis, shortens the waiting time for the detection and analysis results of intermediate products during the production process, and provides rapid feedback on production regulation, which can reduce the frequency of production regulation and improve production efficiency, while achieving precise control of product indicators and stability and consistency of batch product quality.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: a rapid evaluation method for guiding the control of the degree of asphalt polymerization reaction, including pre-evaluation of the relationship between the softening point, coking value, and dynamic viscosity during the polymerization reaction of the asphalt raw material and the polymerization time, making a relationship curve diagram, and monitoring the asphalt viscosity index of the analysis process in a simple and rapid manner during the production process, and then using the relationship curve to trace back the softening point and coking value to determine the reaction end point, thereby guiding the asphalt polymerization production process.

[0007] Further, the following steps are included:

[0008] Step 1: Place the raw material sample into a three-necked flask and raise the temperature to the reaction temperature for polymerization reaction;

[0009] Step 2: Take samples every hour and measure their softening point, coking value and dynamic viscosity;

[0010] Step 3: Prepare the curve of softening point, coking value and dynamic viscosity changing with polymerization time during the polymerization process of raw material samples;

[0011] Step 4: During the production process, monitor the dynamic viscosity of the asphalt during the reaction, and then use the pre-obtained change curve to trace back the softening point and coking value to determine the reaction end point and guide the asphalt polymerization production process.

[0012] Furthermore, the raw material is any one of a coal-based raw material, an oil-based raw material, and a coal-based and oil-based mixed raw material.

[0013] Furthermore, the heating rate is 2-20°C / min, and the polymerization temperature is 300-500°C.

[0014] Furthermore, the dynamic viscosity is tested under fixed temperature conditions, and the test temperature is 30-100°C higher than the softening point of the raw asphalt.

[0015] The present invention is simple, easy, time-saving and labor-saving, eliminates the need for time-consuming indicator analysis, provides rapid feedback on production control, can reduce the frequency of production control, improve production efficiency, and simultaneously achieve precise control of product indicators and stability and consistency of batch product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or related technologies, the following is a brief introduction to the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 is the polymerization reaction temperature curve of Example 1 of the present invention;

[0018] Figure 2 is the polymerization reaction temperature curve of Example 2 of the present invention;

[0019] Figure 3 This is the polymerization reaction temperature curve of Example 3 of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the Figure 1-3 The technical solutions of the present invention are clearly and completely described. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0021] The present invention is described in detail below by specific examples, but the scope of protection of the present invention is not limited. Unless otherwise specified, the experimental methods adopted in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can be obtained from commercial channels.

[0022] In the description of the present invention, it should be noted that the terms "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used solely for distinction and should not be construed as indicating or implying relative importance.

[0023] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] A rapid evaluation method for guiding the control of the degree of asphalt polymerization reaction. By pre-evaluating the relationship between the softening point, coking value, and dynamic viscosity of the asphalt raw material polymerization reaction and polymerization time, and drawing a relationship curve, during the production process, only the asphalt viscosity index of the analysis process is monitored quickly and simply. The relationship curve is then used to back-track the softening point and coking value to determine the reaction endpoint. This method effectively guides the control of the asphalt polymerization production process, shortens the analysis time of intermediate product indicators, reduces the frequency of production control, improves production efficiency, and simultaneously achieves precise control of product indicators and the stability and consistency of batch product quality. The specific operation steps are as follows:

[0025] 1) Place the raw material sample into a three-necked flask and raise the temperature to the reaction temperature to carry out polymerization reaction;

[0026] 2) Take samples every hour and measure their softening point, coking value and dynamic viscosity;

[0027] 3) Prepare the curves of softening point, coking value and dynamic viscosity as a function of polymerization time during the polymerization process of raw material samples;

[0028] 4) During the production process, the dynamic viscosity of the asphalt is monitored during the reaction. The softening point and coking value are then back-tracked using the previously determined curve to determine the reaction endpoint and guide the asphalt polymerization process. The final coking value or softening point of the batch is determined based on production needs or customer-required product quality. The reaction endpoint is reached when the curve meets the required value.

[0029] The raw material can be any of coal-based, oil-based, or a mixture of coal-based and oil-based raw materials. Depending on production needs, the laboratory plots the curve using the same raw material. The heating rate is 2-20°C / min, and the polymerization temperature is 300-500°C. Dynamic viscosity is measured at a fixed temperature, 30-100°C above the softening point of the raw asphalt.

[0030] Example 1

[0031] Coal tar pitch with a softening point of 91.1°C was used as a raw material to prepare a product with a softening point of 200°C and a coking value of 65%. The production polymerization temperature was 350°C. 500g of the same raw material was placed in a three-necked flask in the laboratory, and a stirrer and a thermocouple were installed. The flask was heated in a heating mantle until the temperature reached 350°C. The glass tube was used to sample the product every hour, and the softening point, coking value, and dynamic viscosity at 135°C were measured. The curve was drawn (see Figure 1 ). It can be seen from the curve that as the polymerization time increases, the softening point and coking value of the asphalt gradually increase, and the dynamic viscosity increases. In production, when the polymerization reaches 3h, the sample is taken and the softening point is 121.3℃ and the dynamic viscosity at 135℃ is 97Pas. Figure 1 It can be seen that its degree of polymerization is similar to that of the laboratory reaction for 4.5 hours, and the coking value is about 50%, so the material can be discharged to the next production step.

[0032] Example 2

[0033] A product with a softening point of 180°C and a coking value of 60% was prepared using petroleum asphalt with a softening point of 121.2°C as raw material. The production polymerization temperature was 360°C. 500g of the same raw material was placed in a three-necked flask in the laboratory. A stirrer and a thermocouple were installed. The flask was heated in a heating mantle until the temperature reached 360°C. Samples were taken every hour using a glass tube to measure the softening point, coking value, and 160°C dynamic viscosity. A curve was drawn (see Figure 2 ). It can be seen from the curve that as the polymerization time increases, the softening point of the asphalt first decreases and then increases, the coking value gradually increases, and the dynamic viscosity increases. When the petroleum asphalt reacts, it first cracks and then polymerizes. The cracking and polymerization reactions occur simultaneously. In production, when the polymerization reaches 3h, the sample is taken and the softening point is measured to be 85.8℃, the dynamic viscosity at 160℃ is 26Pas, and the Figure 2, it can be seen that its polymerization degree is similar to that of the laboratory reaction for 5 hours, and the coking value is about 45%, and the polymerization is continued; after 5 hours of polymerization, the softening point is measured to be 108.2℃, and the dynamic viscosity at 160℃ is 31Pas. The polymerization degree is similar to that of the laboratory reaction for 8 hours, and the coking value is about 51%. The material can be discharged and put into the next production. During production monitoring, if only the softening point is tested, it is not possible to judge the stage of the reaction well. If the coking value is tested, it takes a long time. By taking samples for dynamic viscosity test, it is possible to pass Figure 2 The degree of polymerization can be quickly judged, thereby deciding whether to discharge the material or continue polymerization.

[0034] Example 3

[0035] A product with a softening point of 200°C and a coking value of 60% was prepared using medium-low temperature coal tar pitch with a softening point of 109.6°C as raw material. The polymerization temperature was 370°C. 500 g of the same raw material was placed in a three-necked flask in the laboratory. A stirrer and a thermocouple were installed. The flask was heated in a heating mantle until the temperature reached 370°C. A glass tube was used to sample the product every hour. The softening point, coking value, and 160°C dynamic viscosity were measured. A curve was drawn (see Figure 3 ). It can be seen from the curve that as the polymerization time increases, the softening point and coking value of the asphalt gradually increase, and the dynamic viscosity increases. In production, when the sample was taken after 2 hours of polymerization, the softening point was measured to be 153.2℃ and the dynamic viscosity at 160℃ was 175Pas; back to Figure 3 The coking value is about 39%, which is equivalent to the polymerization degree of 3.5 hours in the laboratory; the polymerization can be continued so as to retrospectively determine whether the material is discharged or polymerized.

[0036] The embodiments described above are only preferred embodiments of the present invention, and are not all feasible embodiments of the present invention. For those skilled in the art, any obvious changes made thereto without departing from the principles and spirit of the present invention should be considered to be included in the scope of protection of the claims of the present invention. Although the present invention has been described above with reference to the embodiments, various improvements can be made thereto and components thereof can be replaced by equivalents without departing from the scope of the present invention. In particular, as long as there is no technical conflict, the various features in the embodiments disclosed in the present invention can be used in combination with each other in any way, and the fact that these combinations are not exhaustively described in this specification is simply for the purpose of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A rapid evaluation method for guiding the control of the degree of asphalt polymerization reaction, characterized in that: It includes pre-evaluating the relationship between the softening point, coking value and dynamic viscosity as a function of polymerization time during the polymerization reaction of asphalt raw materials, drawing a relationship curve, monitoring the asphalt viscosity index during the production process in a simple and fast analysis process, and then using the relationship curve to trace back the softening point and coking value to determine the reaction end point, thereby guiding the asphalt polymerization production process.

2. The rapid evaluation method for guiding the control of the degree of asphalt polymerization reaction according to claim 1, characterized in that: The method comprises the following steps: Step 1: Place the raw material sample into a three-necked flask and raise the temperature to the reaction temperature for polymerization reaction; Step 2: Take samples every hour and measure their softening point, coking value and dynamic viscosity; Step 3: Prepare the curve of softening point, coking value and dynamic viscosity changing with polymerization time during the polymerization process of raw material samples; Step 4: During the production process, monitor the dynamic viscosity of the asphalt during the reaction, and then use the pre-obtained change curve to trace back the softening point and coking value to determine the reaction end point and guide the asphalt polymerization production process.

3. The rapid evaluation method for guiding the control of the degree of asphalt polymerization reaction according to claim 1 or 2, characterized in that: The raw material is any one of coal-based raw materials, oil-based raw materials, and coal-based and oil-based mixed raw materials.

4. The rapid evaluation method for guiding the control of the degree of asphalt polymerization reaction according to claim 1 or 2, characterized in that: The heating rate is 2-20°C / min, and the polymerization temperature is 300-500°C.

5. The rapid evaluation method for guiding the control of the degree of asphalt polymerization reaction according to claim 1 or 2, characterized in that: The dynamic viscosity is tested under fixed temperature conditions, and the test temperature is 30-100° C. higher than the softening point of the raw asphalt.

Images