Preparation method of asphalt recombinant product, asphalt recombinant product and asphalt composition

Abstract

The invention discloses a preparation method of an asphalt recombinant product, the asphalt recombinant product and an asphalt composition, and belongs to the technical field of petrochemical engineering. According to the preparation method, light components in asphalt are further eliminated through rectification of matrix asphalt, so that rectification products of hard asphalt and heavy aromatics are recombined to meet different requirements. The method breaks through the limitation of raw materials, has flexibility, can select different recombination routes, realizes preparation of target asphalt, further remarkably improves the flash point of the asphalt, reduces flue gas, improves high temperature resistance and high radiation resistance, and effectively controls the production cost.

Description

Technical Field

[0001] This invention relates to the field of petrochemical technology, and in particular to a method for preparing asphalt reconstituted products, as well as asphalt reconstituted products and asphalt compositions. Background Technology

[0002] Asphalt (petroleum asphalt) has an extremely complex chemical composition, which is usually separated into four components using a four-component analysis method: saturated components (non-polar light components that impart fluidity and lubricity to asphalt; excessive content may lead to insufficient adhesion), aromatic components (medium-polar medium components that are excellent solvents for resins and asphaltenes, maintaining the stability of the asphalt system (colloidal action)), resins (strongly polar heavy components that are the "natural thickeners" and "stabilizers" of asphalt, effectively dispersing asphaltenes and imparting good adhesion and plasticity to asphalt), and asphaltenes (highly polar, high-molecular-weight solid particles that form the "skeleton" of asphalt, determining its hardness, high-temperature performance, and viscosity; however, excessive amounts or aggregation can lead to brittleness and decreased fatigue resistance). The relative proportions and interactions (colloidal structure) of these four components directly determine the type of asphalt, specifically classified as sol-gel (good fluidity), sol-gel (balanced performance), or gel (stable at high temperatures but prone to brittleness).

[0003] Common raw materials for asphalt preparation mainly include naphthenic crude oil, intermediate-based crude oil, and paraffinic crude oil. Naphthenic crude oil is considered an ideal raw material, producing asphalt with moderate amounts of resins and asphaltenes, high aromatic content, and a stable sol-gel structure. It also results in asphalt with high ductility, good adhesion, and low temperature sensitivity (high penetration index). Intermediate-based crude oil is a common raw material; with process adjustments, it can produce acceptable road asphalt, but its performance is generally inferior to naphthenic asphalt. Paraffinic crude oil is a low-quality raw material, producing asphalt with high saturation content (especially wax content), low asphaltene and resin content, and high wax content. This leads to easy softening at high temperatures, easy cracking at low temperatures (high temperature sensitivity), poor adhesion to aggregates, and wax crystallization affecting pavement skid resistance and durability.

[0004] Currently, asphalt preparation typically involves the following two methods:

[0005] I. Atmospheric or vacuum distillation method, the raw material is cycloalkyl or intermediate crude oil, the core function is physical separation, the typical product is road asphalt, the advantages are simple operation, low cost and stable product, the limitation is limited raw material and low product yield.

[0006] II. Solvent deasphalting method: Its raw material is paraffin-based crude oil. Its core function is dewaxing or desaturating hydrocarbons. The typical product is hard or high-grade asphalt. Its advantages are that it can turn inferior residual oil into high-quality oil and improve the utilization rate of raw materials. Its limitations are that the solvent needs to be recovered and the investment cost is high.

[0007] To optimize feedstocks and maximize efficiency, those skilled in the art have begun to study increasing the total crude oil extraction rate, converting the heavier fraction traditionally classified as residue into more valuable distillate oils; providing more and higher-quality feedstocks for downstream heavy oil conversion units, reducing dependence on expensive crude oil; and converting low-value fuel oil or asphalt into high-value light products such as gasoline and diesel, significantly improving the economic efficiency of refineries. A commonly used method is deep distillation, which, based on conventional vacuum distillation, uses a series of technical means to maximize the yield of gas oil (VGO, typically used as feedstock for catalytic cracking or hydrocracking) and extract as much high-value distillate oil as possible from the residue, thereby reducing the yield of low-value, high-impurity residual oil. However, existing technologies still suffer from problems such as equipment clogging, low separation efficiency, high impurity content, and high precision requirements. Specifically: when the temperature exceeds 370℃-380℃, heavy component molecules will undergo thermal decomposition (or thermal cracking), generating unwanted coke and gas, which in turn leads to coking and blockage of equipment, making long-term operation impossible; the viscosity of the deep-drawn oil is extremely high, making it difficult to flow and transfer mass and heat within the tower, easily leading to flooding and reduced efficiency; the heaviest part of the residue oil is rich in metals such as nickel and vanadium and asphaltenes, which can poison the catalysts of downstream units and cause coking; high-precision separation is required within an extremely narrow boiling range, placing extremely high demands on the efficiency of the tower internals.

[0008] Therefore, there is an urgent need to research and develop a new preparation process for asphalt products to overcome the above problems and promote the development and application of asphalt products. Summary of the Invention

[0009] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing asphalt reconstituted products, as well as the asphalt reconstituted products and asphalt compositions. The preparation method overcomes the limitations of raw materials, is flexible, and can significantly improve the flash point of asphalt, reduce smoke emissions, and enhance high-temperature resistance and high-radiation resistance.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] This invention provides a method for preparing a reconstituted asphalt product, comprising the following steps:

[0012] (1) The naphthenic crude oil is fractionated to obtain aromatic feedstock and matrix pitch, and the aromatic feedstock is distilled in the first distillation unit to obtain heavy aromatics;

[0013] (2) The matrix asphalt is distilled in a second distillation unit to obtain distilled hard asphalt, which is then mixed with the heavy aromatics to obtain asphalt reconstituted product A;

[0014] Alternatively, the base asphalt and the heavy aromatics are mixed and then distilled in a second distillation unit to obtain asphalt recombinant product B, which is a recombinant product of distilled hard asphalt and heavy aromatics.

[0015] The penetration of the distilled hard pitch at 25°C is preferably 13-18 mm; more preferably 15 mm.

[0016] The preparation method of this invention further separates naphthenic crude oil through a combination of a first distillation unit and a second distillation unit, achieving the recombination of distilled hard asphalt and heavy aromatics, thereby improving the performance of the asphalt product. The preparation method is not limited to specific raw materials and offers flexibility in process selection. Different naphthenic crude oils and different recombination routes can be selected according to different needs to achieve the preparation of the target asphalt.

[0017] In the above preparation method, both the first distillation unit and the second distillation unit are distillation columns. To meet the diverse needs of domestic and international manufacturers for reconstituted asphalt products, the parameters in the preparation method can be specifically optimized.

[0018] Preferably, the distillation temperature in step (2) of this invention is 320℃-340℃; more preferably, it is 325℃-335℃.

[0019] Preferably, in this invention, the second distillation apparatus is selected from a distillation column;

[0020] Preferably, the vacuum degree at the top of the distillation column is 15-40 mmHg; more preferably, it is 25-40 mmHg. Preferably, the temperature at the top of the distillation column is 90℃-110℃; more preferably, it is 95℃-105℃.

[0021] Preferably, the fractionation temperature in step (1) of this invention is 330℃-350℃; more preferably, it is 335℃-345℃.

[0022] Preferably, the fractionation is carried out in a fractionation tower.

[0023] Preferably, the vacuum degree at the top of the fractionation column is 15-40 mmHg, and the temperature at the top of the column is not greater than 100°C. More preferably, the vacuum degree at the top of the fractionation column is 30-40 mmHg, and the temperature at the top of the column is not greater than 80°C.

[0024] Preferably, the temperature of the aromatic material in step (1) is controlled at 320°C-340°C before entering the first distillation apparatus; more preferably, it is controlled at 325°C-335°C.

[0025] Preferably, the conditions for obtaining heavy aromatics by distillation in step (1) include:

[0026] The temperature should be controlled at 300℃-320℃, and the initial boiling point should not be lower than 450℃.

[0027] More preferably, the temperature is controlled at 305℃-315℃.

[0028] The first distillation unit is an aromatic distillation column, with diesel components exiting from the top, light aromatic components exiting from the side stream, and heavy aromatic components exiting from the bottom.

[0029] The distillation column is an asphalt distillation column, which produces diesel components at the top, aromatic components on the side stream, and hard asphalt (distilled hard asphalt) at the bottom.

[0030] The heavy aromatic components separated from the aromatic distillation column can be recombined with the hard asphalt online to prepare asphalt recombined product A, or they can first enter the asphalt distillation column and recombine with the hard asphalt inside the column to prepare asphalt recombined product B.

[0031] Preferably, the distillation products of step (1) of this invention further include light aromatics and diesel oil;

[0032] Preferably, the initial boiling point of the light aromatic hydrocarbon is not less than 400°C;

[0033] Preferably, the final boiling point of the diesel fuel is not greater than 380°C.

[0034] The present invention also provides an asphalt reconstituted product, which is prepared by the above-described preparation method.

[0035] In the process equipment described in this invention, the aromatic distillation tower and the pitch distillation tower are designed as negative pressure towers, and the vacuum system needs to be set up separately, with the capacity to meet the needs of bottom steam injection.

[0036] The asphalt distillation tower has three layers of packing inside and one side stream product outside. The side stream separates out light aromatic components (which can be recovered to the aromatic distillation tower), and hard asphalt is separated at the bottom of the tower.

[0037] The aromatic distillation column has four layers of packing. The product at the top is diesel fuel, and the column diameter is 3.2 meters. The product at the bottom is light aromatics, and the product at the bottom is heavy aromatics, with a column diameter of 4.5 meters. It has two side stream products: one is diesel fuel, and the other is light aromatics. The product at the bottom is heavy aromatics.

[0038] A heating device is installed before the aromatics distillation column to heat the aromatic components separated from the fractionation column. The heated aromatic components are then fed into the aromatics distillation column as feedstock to achieve further separation of aromatics.

[0039] The heating device can be a heating furnace. The load of the heating furnace is preferably 3.5-4.5 MW.

[0040] In addition to the above-mentioned devices, the process equipment of the present invention also includes an asphalt mass flow meter, a regulating valve, a vacuum system, an asphalt first-line pump, an asphalt pump, an aromatics distillation tower first-line pump, an aromatics distillation tower second-line pump, an aromatics distillation tower bottom pump, a vacuum tank oil pump, a tank water pump, a vacuum system separator, an asphalt storage tank, and supporting facilities, etc. The first-line and second-line pumps refer to the side-line pumps of the asphalt distillation tower or the aromatics distillation tower.

[0041] To optimize asphalt product indicators and further reduce asphalt fumes, functional additives or other component mixtures can be added to produce high-end asphalt products.

[0042] The present invention also provides an asphalt composition comprising the above-described asphalt reconstituted product and acceptable functional additives.

[0043] Preferably, the acceptable functional additives of this invention include, but are not limited to, heavy aromatic oils or cosolvents.

[0044] Adding heavy aromatics can increase the production of high-end asphalt, and external procurement is generally used to supplement production when domestic production is insufficient; co-solvents can improve some indicators of asphalt and are classified as functional additives.

[0045] Compared with the prior art, the preparation method of the asphalt reconstituted product provided by the present invention includes the following steps:

[0046] (1) Naphthenic crude oil is fractionated to obtain aromatic feedstock and matrix asphalt. The aromatic feedstock is then distilled in a first distillation unit to obtain heavy aromatics. (2) The matrix asphalt is distilled in a second distillation unit to obtain distilled hard asphalt, which is then mixed with the heavy aromatics to obtain asphalt reconstituted product A. Alternatively, the matrix asphalt is mixed with the heavy aromatics and then distilled in a second distillation unit to obtain asphalt reconstituted product B after the distilled hard asphalt and heavy aromatics are reconstituted. The distilled hard asphalt has a penetration of 13-18 mm at 25°C. The preparation method further eliminates light components and cracked light hydrocarbon components in the asphalt through the distillation of matrix asphalt, and reconstitutes the distilled hard asphalt and heavy aromatics to achieve the preparation of asphalt reconstituted products with different requirements. The method breaks through the limitations of raw materials, has flexibility, and can select different reconstituted routes to achieve the preparation of target asphalt, thereby significantly improving the flash point of asphalt, reducing smoke, improving high temperature resistance and high radiation resistance, effectively controlling costs, significantly improving product competitiveness, and realizing green production of asphalt products. Attached Figure Description

[0047] Figure 1 This is a process flow diagram of the preparation method of the asphalt reconstituted product of the present invention. Detailed Implementation

[0048] To further illustrate the present invention, the preparation method of the asphalt reconstituted product, the asphalt reconstituted product, and the asphalt composition provided by the present invention are described in detail below with reference to embodiments.

[0049] The process flow diagram of the present invention is as follows: Figure 1 As shown. The specific process route is as follows:

[0050] Heavy asphalt (naphthenic crude oil) is fed into a fractionation tower. The vacuum at the top of the fractionation tower is controlled at 15-40 mmHg, and the temperature at the top of the tower is controlled not to exceed 100°C. The matrix asphalt is separated from the bottom of the tower, and aromatics are separated from the side stream. The aromatics are then heated to 320°C-340°C in a heater and fed into an aromatics rectification tower. Different temperatures and final boiling points are controlled, and light aromatics are separated from the side stream. These can be used alone or in combination as raw materials for other applications. Heavy aromatics are separated from the bottom of the aromatics rectification tower. These can be used alone as raw materials for other applications, or they can be used as raw materials in the preparation of the asphalt reconstituted products described in this invention.

[0051] The matrix pitch separated from the bottom of the fractionation column is fed to the pitch rectification column, where light aromatic hydrocarbon components are separated by a side stream, and hard pitch (hard pitch) is separated from the bottom of the column. The hard pitch and heavy aromatic hydrocarbons are then recombinated to prepare the reconstituted pitch product. The recombination process specifically involves two routes:

[0052] Route (1): Only the base asphalt enters the asphalt distillation tower, and hard asphalt is separated at the bottom of the tower. The hard asphalt is directly recombined with the heavy aromatics separated at the bottom of the aromatic distillation tower to obtain asphalt recombined product A.

[0053] Route (2): The heavy aromatics separated from the bottom of the aromatic distillation tower enter the asphalt distillation tower, and the light aromatic components are separated through the side stream of the asphalt distillation tower. The recombinant product of the distilled hard asphalt (such as No. 10 low grade asphalt) and heavy aromatics separated from the bottom of the tower is asphalt recombinant product B.

[0054] In Example 1 below, the feed to the asphalt distillation tower is only base asphalt, and the output product is hard asphalt. The hard asphalt is directly recombined with the heavy aromatics output from the aromatics distillation tower to obtain asphalt recombined product A. In Example 2, the feed to the asphalt distillation tower is base asphalt and the bottom output heavy aromatics from the aromatics distillation tower. The output product is asphalt recombined product B obtained by recombining hard asphalt and heavy aromatics.

[0055] Example 1

[0056] (1) The heavy asphalt material (mainly naphthenic crude oil) is heated to 340°C via heat exchange and then fed into a fractionation tower. The vacuum degree at the top of the fractionation tower is controlled at 40 mmHg, and the temperature at the top of the tower is controlled not to exceed 80°C. The heavy asphalt material is separated into aromatic material and matrix asphalt. The aromatic material is discharged from the side stream at 280°C and enters the aromatic heating furnace (i.e., the... Figure 1The diesel fuel is heated to 330°C in the medium heating furnace and enters the aromatics distillation column. The top temperature of the column is controlled at 120°C to separate the diesel fuel from the top of the column, with its final boiling point not exceeding 380°C. The light aromatics with lower flash points are separated from the side stream, with the initial boiling point controlled at ≥400°C (≥ means not less than), and used as feedstock for other units.

[0057] Heavy aromatics at the bottom of the tower are discharged at 310℃, and the initial boiling point is controlled to be no less than 450℃. This product is an important component of high-end customized asphalt and is used to improve the high-temperature performance and heat-sensitive properties of asphalt.

[0058] (2) The base asphalt is drawn from the fractionation tower at 330℃ and enters the asphalt rectification tower. The temperature at the top of the tower is controlled at 100℃ and the vacuum at the top of the tower is 40 mmHg. The side stream extracts the mixed aromatics in the base asphalt, so that the mixed aromatics re-enter the aromatics rectification tower for separation, thereby reducing the influence of light components on the asphalt index. The No. 10 low-grade asphalt (i.e., the base asphalt) is drawn from the bottom of the tower at 320℃. Figure 1 Medium-hard asphalt, also known as No. 10 building petroleum asphalt, corresponds to the current national standard GB / T 494-2025 "Building Petroleum Asphalt". It involves directly recombinating the heavy aromatics separated from the bottom of the aromatics distillation column with the No. 10 low-grade asphalt (recombination outside the asphalt distillation column, i.e.,...). Figure 1 The process (1) yields asphalt reconstituted product A, which consists of 10% heavy aromatics and 70% hard asphalt. This process meets the requirements for the production of customized high-end asphalt.

[0059] Asphalt road performance evaluation tests showed that the asphalt reconstituted product A prepared in Example 1 exhibited excellent high-temperature resistance. The flash point of asphalt reconstituted product A was above 290℃. When heated to 180℃, asphalt reconstituted product A produced minimal smoke.

[0060] The excellent high-temperature resistance enhances the internal skeleton strength and viscosity of the asphalt reconstituted product A, making it highly resistant to rutting.

[0061] Example 2

[0062] Same as in Example 1, except that step (2) is:

[0063] The base asphalt is drawn from the fractionation tower at 330°C and enters the asphalt rectification tower. Heavy aromatics separated from the bottom of the aromatics rectification tower also enter the asphalt rectification tower (recombination occurs within the asphalt rectification tower, i.e....). Figure 1 In the route (2), the top temperature of the tower is controlled at 100℃ and the top vacuum is 40 mmHg. The side stream extracts the mixed aromatics from the base asphalt, allowing the mixed aromatics to re-enter the aromatics distillation tower for separation, thus reducing the influence of light components on the asphalt index. At the bottom of the tower, at 320℃, No. 10 low-grade asphalt (i.e., the base asphalt) is extracted. Figure 1The recombinant product of medium-hard asphalt and heavy aromatics is asphalt recombinant product B, which consists of 10% heavy aromatics and 70% hard asphalt. The process described meets the requirements for the production of customized high-end asphalt.

[0064] Asphalt road performance evaluation tests showed that the asphalt reconstituted product B prepared in Example 2 exhibited excellent high-temperature resistance. The flash point of the asphalt reconstituted product B was above 290℃. When heated to 180℃, the asphalt reconstituted product B produced minimal smoke.

[0065] The production process described in this invention can be adjusted and matched according to the different requirements of different customers for asphalt product components, so as to realize the recombination of asphalt components and achieve customized production of high-end asphalt.

[0066] In the process route described in this invention, the base asphalt can also be recombinated with the heavy aromatic components discharged from the bottom of the aromatic distillation column to obtain asphalt recombination product C. The base asphalt can also be collected separately and used as raw material for other processes.

[0067] If the asphalt reconstituted product A, B, or C is mixed with different functional additives and other blending agents (such as additives, blending materials, aromatic materials, etc.), and different distillation ranges are clearly cut according to the blending material requirements of different asphalt products, the aromatic materials in different distillation ranges can be combined with hard asphalt to prepare different types of asphalt products such as waterproof asphalt, high-end environmentally friendly asphalt, customized special asphalt, etc.

[0068] According to requirements, process parameters are adjusted so that the process described in this invention can meet various domestic and international asphalt product standards and be successfully delivered. Specific details are shown in Table 1:

[0069] Table 1. Domestic and international asphalt products of different grades / key indicators prepared using the process of this invention.

[0070]

[0071] The preparation method described in this invention is applicable to different regions, environments, temperatures, humidity levels, and radiation. Analysis and research on different components suitable for different countries and regions can improve the long-term performance of asphalt. Based on different raw material components, the asphalt components are clearly cut according to different processes, and then combined with asphaltenes and resins in different proportions to meet the production needs of asphalt in different environments, regions, and with varying high and low temperature performance. Simultaneously, it can also be product-oriented, analyzing the required components and proportions of raw materials, and procuring relevant raw materials or additives from the market to achieve customized asphalt production. To meet high-temperature performance requirements, the proportion of asphaltenes and resins in the asphalt can be increased; to improve adhesion, the content of resins and aromatic components can be increased; at the same time, the performance indicators of asphalt can be improved by combining functional additives, thereby achieving efficient production.

[0072] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing an asphalt reconstituted product, characterized in that, Includes the following steps: (1) The naphthenic crude oil is fractionated to obtain aromatic feedstock and matrix pitch, and the aromatic feedstock is distilled in the first distillation unit to obtain heavy aromatics; (2) The matrix asphalt is distilled in a second distillation unit to obtain distilled hard asphalt, which is then mixed with the heavy aromatics to obtain asphalt reconstituted product A; Alternatively, the base asphalt and the heavy aromatics are mixed and then distilled in a second distillation unit to obtain asphalt recombinant product B, which is a recombinant product of distilled hard asphalt and heavy aromatics. The distilled hard pitch has a penetration of 13-18 mm at 25°C.

2. The preparation method according to claim 1, characterized in that, The distillation temperature in step (2) is 320℃-340℃.

3. The preparation method according to claim 2, characterized in that, The second distillation unit is selected from a distillation column; The distillation column has a top vacuum of 15-40 mmHg and a top temperature of 90℃-110℃.

4. The preparation method according to claim 1, characterized in that, The fractionation temperature in step (1) is 330℃-350℃.

5. The preparation method according to claim 4, characterized in that, The fractionation is carried out in a fractionation column; The vacuum degree at the top of the distillation column is 15-40 mmHg, and the temperature at the top of the column is not greater than 100℃.

6. The preparation method according to claim 1, characterized in that, The temperature of the aromatic material in step (1) is controlled at 320℃-340℃ before entering the first distillation unit.

7. The preparation method according to claim 6, characterized in that, The conditions for obtaining heavy aromatics by distillation in step (1) include: The temperature should be controlled at 300℃-320℃, and the initial boiling point should not be lower than 450℃.

8. The preparation method according to claim 1, characterized in that, The distillation products of step (1) also include light aromatics and diesel oil; the initial boiling point of the light aromatics is not less than 400°C. The final boiling point of the diesel fuel is no greater than 380°C.

9. A reconstituted asphalt product, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. An asphalt composition, characterized in that, It includes the asphalt reconstituted product as described in claim 9 and acceptable functional additives.

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