A method for preparing high-grade road asphalt

Abstract

The invention discloses a method for preparing high-grade road asphalt, and belongs to the technical field of petrochemical industry. A method for preparing high-grade road asphalt of the invention is to separate the extracted raw material vacuum residue oil through a butane solvent deasphalting process to obtain asphaltene and colloid, and then blend the asphaltene, colloid and vacuum residue oil to obtain high-grade road asphalt. The invention adopts a method for preparing high-grade road asphalt by blending vacuum residue oil with desorbed colloid and asphaltene, which improves the yield of colloid, can effectively control the quality of road asphalt products, and the process required for the preparation method is simple, and can be carried out in the desorbing device of an oil refinery.

Description

Technical Field

[0001] The invention relates to a method for preparing high-grade road asphalt, and belongs to the technical field of petrochemical industry. Background Art

[0002] Asphalt is an indispensable material for building high-grade roads. With the rapid growth of global highway mileage, the demand for asphalt, especially high-grade heavy traffic asphalt, is increasing. The blending method for preparing asphalt occupies an important position in the world's asphalt production process. The blending method for producing asphalt refers to adjusting the ratio between asphalt components according to the requirements of asphalt quality or colloid structure to obtain a product that can meet the use requirements. At present, the domestic road asphalt market demand is strong, and there are many methods for producing road asphalt. Most of them are based on vacuum distillation direct asphalt, and some use solvent deasphalting technology to blend and produce road asphalt. Due to the limitations of the solvent deasphalting process, the yield of the intermediate product colloid is low, and the output of road asphalt produced by blending colloid and asphalt is limited. At the same time, a large amount of surplus asphalt can only be sent to coking for blending, which reduces the efficiency of the device. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing high-grade road asphalt.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for preparing high-grade road asphalt, the method comprising the following two steps:

[0006] (1) subjecting vacuum residue to primary extraction through a solvent deasphalting process to obtain an asphaltene phase and an oil phase, the asphaltene phase is subjected to a solvent removal treatment to obtain asphaltene, the oil phase is subjected to secondary extraction and separation to obtain a deasphalted oil solution and a colloid solution, the colloid solution is subjected to a solvent removal treatment to obtain colloid, wherein the solvent used in the solvent deasphalting process is at least one of butane and pentane;

[0007] (2) Mixing the asphaltenes, colloids and vacuum residue obtained in step (1) to obtain the high-grade road asphalt.

[0008] The invention adopts a method for preparing high-grade road asphalt by blending vacuum residue oil, colloid and asphaltene, which can effectively control the quality of road asphalt products and has low requirements on raw material properties, thereby solving the problem of oil refining enterprises preparing high-grade road asphalt safely and reliably.

[0009] As a preferred embodiment of the method for preparing high-grade road asphalt according to the present invention, in the step (1), the asphaltene solution and the colloid solution are separated and butane is recovered by steam stripping, and the oil phase is subjected to secondary extraction in a colloid settler.

[0010] Studies have shown that the solubility of general substances in solvents increases with increasing temperature, but for some low-boiling point alkane solvents, such as propane, butane, and pentane, when the temperature rises to a certain value, their solubility decreases with increasing temperature. When the critical temperature is reached, they become gaseous and insoluble. Solvent deasphalting uses vacuum residue as raw material. Under certain temperature and pressure conditions, butane or pentane liquid solvents are used to extract the oil components in vacuum residue, but they have almost no solubility in colloid and asphaltene. The solvents are extracted in an extractor to separate them into an extraction solution phase and an asphalt solution phase. Due to the density difference between the two phases, the extraction solution phase with a smaller specific gravity gradually rises to the top of the extractor to become an extract, and the asphalt solution phase with a larger specific gravity sinks to the bottom. The extract is ejected from the top of the extractor and the solvent selectivity is increased by heating, so that the colloid and asphaltene are settled in the settler. In this way, the colloid and asphaltene in the residue are removed to obtain a deasphalted oil solution. Finally, the solvents contained in the colloid solution, asphaltene solution and deasphalted oil solution are recovered respectively to obtain deasphalted oil and raw materials for blending road asphalt. By taking advantage of the fact that the solvent loses its ability to dissolve oil components as the temperature rises, the solvent loses its ability to dissolve oil components under the supercritical state where the pressure is not very high and the temperature is high, so that the solvent and the extracted oil can be separated and the supercritical recovery of the solvent can be achieved. The solvent contained in the colloid and asphalt is recovered by evaporation and stripping at a high temperature and then recycled. This subcritical extraction and supercritical recovery process has the characteristics of simple process, less equipment and low energy consumption.

[0011] As a preferred embodiment of the method for preparing high-grade road asphalt according to the present invention, the weight ratio of butane to the vacuum residue oil of the extraction raw material in step (1) is 2.5-3.5:1.

[0012] Studies have shown that the weight ratio of butane solvent to vacuum residue oil has an effect on the extraction of colloids and asphaltene. Increasing the weight ratio of butane solvent to vacuum residue oil increases the extraction depth, increases the yield of deasphalted oil, decreases the yield of colloids and asphaltene, and increases the softening point. During the operation, it is always hoped to increase the yield of deasphalted oil, which will tend to have a higher solvent ratio, but this will increase the solvent circulation and feed volume, resulting in a significant increase in the power consumption of high-voltage motors and furnace fuel oil and gas, and increase energy consumption and operating costs. Therefore, the weight ratio of butane solvent to vacuum residue oil should be controlled within an appropriate range. The weight ratio of butane solvent to vacuum residue oil should be reasonably selected according to the DMO quality requirements, raw material properties and solvent composition; studies have shown that the weight ratio of butane solvent to vacuum residue oil is best controlled between 2.5 and 3.5.

[0013] As a preferred embodiment of the method for preparing high-grade road asphalt of the present invention, the mass ratio of asphaltene, colloid and vacuum residue in step (2) is asphaltene: colloid: vacuum residue = (3-13): (5.1-6.9): (10-67). Studies have shown that the mass ratio of asphaltene, colloid and vacuum residue has a great influence on the penetration, softening point and elongation of the final prepared asphalt.

[0014] As a preferred embodiment of the method for preparing high-grade road asphalt according to the present invention, the extraction temperature of the primary extraction is 105-135°C.

[0015] As a preferred embodiment of the method for preparing high-grade road asphalt of the present invention, the oil phase is preheated to 125-145°C before the secondary extraction, and the extraction temperature of the secondary extraction is 125-145°C.

[0016] As a preferred embodiment of the method for preparing high-grade road asphalt described in the present invention, the asphaltene phase is preheated to 290-315°C before steaming, and the steam stripping pressure of the asphaltene phase is 0.66-0.76MPa; the colloid solution is preheated to 250-288°C before steaming, and the steam stripping pressure of the colloid solution is 0.66-0.76MPa.

[0017] As a preferred embodiment of the method for preparing high-grade road asphalt according to the present invention, the mixing temperature in step (2) is 150-220°C.

[0018] As a preferred embodiment of the method for preparing high-grade road asphalt according to the present invention, the mixing of asphaltene, colloid and vacuum residue in step (2) is carried out in a static mixer. After the asphaltene, colloid and vacuum residue are mixed in step (2), they are cooled to 120-160°C by heat exchange.

[0019] Static mixers allow fluids to flow in pipelines and impact various types of plate elements, increasing the velocity gradient of fluid laminar flow or forming turbulence. In laminar flow, it is "division-position movement-reunion". In turbulent flow, in addition to the above three situations, the fluid will also produce violent vortices in the cross-sectional direction, with strong shear force acting on the fluid, causing the fluid to further divide and mix, and finally mix to form the required emulsion. The mixing process of the static mixer is carried out by a series of mixing units of different specifications installed in the hollow pipe. Due to the action of the mixing unit, the fluid sometimes rotates left and sometimes rotates right, constantly changing the direction of the flow mixer, not only pushing the central fluid to the periphery, but also pushing the peripheral fluid to the center, thereby creating a good radial mixing effect. At the same time, the rotation of the fluid itself will also occur at the interface where the adjacent components are connected. This perfect radial circulation mixing effect enables the material to be mixed evenly. Static mixers are a high-efficiency mixing device without movement. Through the internals of the mixing unit fixed in the pipe, two or more streams of fluid are cut, sheared, rotated and remixed, so as to achieve the purpose of good dispersion and full mixing between the fluids.

[0020] The present invention also provides high-grade road asphalt prepared by the above-mentioned method for preparing high-grade road asphalt.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention improves the yield of colloid by selecting various parameters of the solvent deasphalting process; the preparation method of the high-grade road asphalt of the present invention uses vacuum residue oil as a soft component for blending, which greatly increases the blending amount of asphaltene, reduces the asphaltene sent to the coking plant for blending, reduces the output of by-products, and improves the efficiency of the device; the present invention produces qualified road asphalt by adjusting the ratio of the three components of vacuum residue oil, colloid and asphaltene, and the production method requires a simple process, which can be carried out in the solvent removal device of an oil refinery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The following are process flow charts of various embodiments. DETAILED DESCRIPTION

[0023] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0024] Example 1

[0025] A method for preparing high-grade road asphalt according to an embodiment of the present invention:

[0026] (1) The raw material vacuum residue enters the solvent deasphalting raw material tank, is pressurized to 6.2MPa by the raw material pump, and is mixed with the high-pressure circulating solvent before entering the extractor for primary extraction. The extraction temperature is 120℃, and the asphaltene butane solution is extracted from the bottom of the extractor; the asphaltene butane solution is automatically pressed to the asphalt solution heating furnace and heated to 310℃ before entering the stripping tower. The separated butane solvent is recycled, and the asphaltene is separated from the bottom of the stripping tower; the extract at the top of the extractor is heated to 135℃ after heat exchange and enters the colloid settler for secondary extraction. The deasphalted oil solution is separated from the top of the colloid settler, and the colloid solution is separated from the bottom. The colloid solution is heated to 270℃ in the heating furnace and enters the stripping tower. The separated butane solvent is recycled, and the colloid is separated from the bottom of the stripping tower. During the entire extraction process, the weight ratio of butane solvent to the extracted raw material vacuum residue is 3:1.

[0027] (2) The asphaltene, colloid and vacuum residue obtained in step 1 are placed in a static mixer in a mass ratio of asphaltene: colloid: vacuum residue = 3:6.3:10, the mixing temperature is 160° C., and the mixture is cooled to 140° C. through heat exchange to obtain the high-grade road asphalt.

[0028] Example 2

[0029] A method for preparing high-grade road asphalt according to an embodiment of the present invention:

[0030] (1) The raw material vacuum residue enters the solvent deasphalting raw material tank, is pressurized to 6.2MPa by the raw material pump, and then mixed with the high-pressure circulating solvent and enters the extractor for primary extraction. The extraction temperature is 105℃, and the asphaltene butane solution is extracted from the bottom of the extractor; the asphaltene butane solution is automatically pressed to the asphalt solution heating furnace and heated to 290℃ before entering the stripping tower. The separated butane solvent is recycled, and the asphaltene is separated from the bottom of the stripping tower; the extract at the top of the extractor is heated to 125℃ after heat exchange and enters the colloid settler for secondary extraction. The deasphalted oil solution is separated from the top of the colloid settler, and the colloid solution is separated from the bottom. The colloid solution is heated to 250℃ in the heating furnace and enters the stripping tower. The separated butane solvent is recycled, and the colloid is separated from the bottom of the stripping tower. During the entire extraction process, the weight ratio of butane solvent to the extracted raw material vacuum residue is 2.5:1.

[0031] (2) The asphaltene, colloid and vacuum residue obtained in step 1 are placed in a static mixer in a mass ratio of asphaltene: colloid: vacuum residue = 6.2:6.6:66, and the mixing temperature is 150° C. The mixture is cooled to 120° C. by heat exchange to obtain the high-grade road asphalt.

[0032] Example 3

[0033] A method for preparing high-grade road asphalt according to an embodiment of the present invention:

[0034] (1) The raw material vacuum residue enters the solvent deasphalting raw material tank, is pressurized to 6.2MPa by the raw material pump, and is mixed with the high-pressure circulating solvent before entering the extractor for primary extraction. The extraction temperature is 135℃, and the asphaltene butane solution is extracted from the bottom of the extractor; the asphaltene butane solution is automatically pressurized to the asphalt solution heating furnace and heated to 315℃ before entering the stripping tower. The separated butane solvent is recycled, and the asphaltene is separated from the bottom of the stripping tower; the extract at the top of the extractor is heated to 145℃ after heat exchange and enters the colloid settler for secondary extraction. The deasphalted oil solution is separated from the top of the colloid settler, and the colloid solution is separated from the bottom. The colloid solution is heated to 288℃ in the heating furnace and enters the stripping tower. The separated butane solvent is recycled, and the colloid is separated from the bottom of the stripping tower. During the entire extraction process, the weight ratio of butane solvent to the extracted raw material vacuum residue is 3.5:1.

[0035] (2) The asphaltene, colloid and vacuum residue obtained in step 1 are placed in a static mixer in a mass ratio of asphaltene: colloid: vacuum residue = 5.5:6.9:50, the mixing temperature is 160° C., and the mixture is cooled to 150° C. by heat exchange to obtain the high-grade road asphalt.

[0036] Example 4

[0037] A method for preparing high-grade road asphalt according to an embodiment of the present invention:

[0038] (1) The raw material vacuum residue enters the solvent deasphalting raw material tank, is pressurized to 6.2MPa by the raw material pump, and is mixed with the high-pressure circulating solvent before entering the extractor for primary extraction. The extraction temperature is 120℃, and the asphaltene butane solution is extracted from the bottom of the extractor; the asphaltene butane solution is automatically pressed to the asphalt solution heating furnace and heated to 310℃ before entering the stripping tower. The separated butane solvent is recycled, and the asphaltene is separated from the bottom of the stripping tower; the extract at the top of the extractor is heated to 135℃ after heat exchange and enters the colloid settler for secondary extraction. The deasphalted oil solution is separated from the top of the colloid settler, and the colloid solution is separated from the bottom. The colloid solution is heated to 270℃ in the heating furnace and enters the stripping tower. The separated butane solvent is recycled, and the colloid is separated from the bottom of the stripping tower. During the entire extraction process, the weight ratio of butane solvent to the extracted raw material vacuum residue is 3:1.

[0039] (2) The asphaltene, colloid and vacuum residue obtained in step 1 are placed in a static mixer in a mass ratio of asphaltene: colloid: vacuum residue = 10.5:5.2:67, the mixing temperature is 160° C., and the mixture is cooled to 140° C. through heat exchange to obtain the high-grade road asphalt.

[0040] Example 5

[0041] A method for preparing high-grade road asphalt according to an embodiment of the present invention:

[0042] (1) The raw material vacuum residue enters the solvent deasphalting raw material tank, is pressurized to 6.2MPa by the raw material pump, and is mixed with the high-pressure circulating solvent before entering the extractor for primary extraction. The extraction temperature is 120℃, and the asphaltene butane solution is extracted from the bottom of the extractor; the asphaltene butane solution is automatically pressed to the asphalt solution heating furnace and heated to 310℃ before entering the stripping tower. The separated butane solvent is recycled, and the asphaltene is separated from the bottom of the stripping tower; the extract at the top of the extractor is heated to 135℃ after heat exchange and enters the colloid settler for secondary extraction. The deasphalted oil solution is separated from the top of the colloid settler, and the colloid solution is separated from the bottom. The colloid solution is heated to 270℃ in the heating furnace and enters the stripping tower. The separated butane solvent is recycled, and the colloid is separated from the bottom of the stripping tower. During the entire extraction process, the weight ratio of butane solvent to the extracted raw material vacuum residue is 3:1.

[0043] (2) The asphaltene, colloid and vacuum residue obtained in step 1 are placed in a static mixer in a mass ratio of asphaltene: colloid: vacuum residue = 13:5.1:62, the mixing temperature is 160° C., and the mixture is cooled to 140° C. through heat exchange to obtain the high-grade road asphalt.

[0044] Example 6

[0045] A method for preparing high-grade road asphalt according to an embodiment of the present invention:

[0046] (1) The raw material vacuum residue enters the solvent deasphalting raw material tank, is pressurized to 6.2MPa by the raw material pump, and is mixed with the high-pressure circulating solvent before entering the extractor for primary extraction. The extraction temperature is 120℃, and the asphaltene butane solution is extracted from the bottom of the extractor; the asphaltene butane solution is automatically pressed to the asphalt solution heating furnace and heated to 310℃ before entering the stripping tower. The separated butane solvent is recycled, and the asphaltene is separated from the bottom of the stripping tower; the extract at the top of the extractor is heated to 135℃ after heat exchange and enters the colloid settler for secondary extraction. The deasphalted oil solution is separated from the top of the colloid settler, and the colloid solution is separated from the bottom. The colloid solution is heated to 270℃ in the heating furnace and enters the stripping tower. The separated butane solvent is recycled, and the colloid is separated from the bottom of the stripping tower. During the entire extraction process, the weight ratio of butane solvent to the extracted raw material vacuum residue is 3:1.

[0047] (2) The asphaltene, colloid and vacuum residue obtained in step 1 are placed in a static mixer in a mass ratio of asphaltene: colloid: vacuum residue = 9.2:6.1:63, the mixing temperature is 160° C., and the mixture is cooled to 140° C. through heat exchange to obtain the high-grade road asphalt.

[0048] Example 7

[0049] A method for preparing high-grade road asphalt according to an embodiment of the present invention:

[0050] (1) The raw material vacuum residue enters the solvent deasphalting raw material tank, is pressurized to 6.2MPa by the raw material pump, and is mixed with the high-pressure circulating solvent before entering the extractor for primary extraction. The extraction temperature is 120℃, and the asphaltene butane solution is extracted from the bottom of the extractor; the asphaltene butane solution is automatically pressed to the asphalt solution heating furnace and heated to 310℃ before entering the stripping tower. The separated butane solvent is recycled, and the asphaltene is separated from the bottom of the stripping tower; the extract at the top of the extractor is heated to 135℃ after heat exchange and enters the colloid settler for secondary extraction. The deasphalted oil solution is separated from the top of the colloid settler, and the colloid solution is separated from the bottom. The colloid solution is heated to 270℃ in the heating furnace and enters the stripping tower. The separated butane solvent is recycled, and the colloid is separated from the bottom of the stripping tower. During the entire extraction process, the weight ratio of butane solvent to the extracted raw material vacuum residue is 3:1.

[0051] (2) The asphaltene, colloid and vacuum residue obtained in step 1 are placed in a static mixer in a mass ratio of asphaltene: colloid: vacuum residue = 7.2:6.7:45, the mixing temperature is 160° C., and the mixture is cooled to 140° C. through heat exchange to obtain the high-grade road asphalt.

[0052] Comparative Example 1

[0053] The difference between this comparative example and Example 2 is only that the mass ratio of asphaltene, colloid and vacuum residue is different. In this comparative example, the mass ratio of asphaltene, colloid and vacuum residue is asphaltene: colloid: vacuum residue = 6.2:8:66.

[0054] Comparative Example 2

[0055] The difference between this comparative example and Example 2 is only that the mass ratio of asphaltene, colloid and vacuum residue is different. In this comparative example, the mass ratio of asphaltene, colloid and vacuum residue is asphaltene: colloid: vacuum residue = 15:6.6:66.

[0056] Comparative Example 3

[0057] The difference between this comparative example and Example 2 is that the mass ratio of asphaltene, colloid and vacuum residue is different. In this comparative example, the mass ratio of asphaltene, colloid and vacuum residue is asphaltene: colloid: vacuum residue = 6.2:6.6:70.

[0058] Effect example

[0059] 1. The yields of the gums and asphaltene prepared in Examples 1 to 7 and Comparative Examples 1 to 3 were measured. The results are shown in Table 1.

[0060] 2. The deoiling rate and heavy metal removal rate of the deasphalted oil prepared in Examples 1 to 7 and Comparative Examples 1 to 3 were measured. The results are shown in Table 1.

[0061] 3. The penetration, softening point, elongation and dynamic viscosity of the high-grade road asphalt prepared in Examples 1 to 7 and Comparative Examples 1 to 3 were tested according to standard JTGF40-2004. The experimental results are shown in Table 1.

[0062] Table 1

[0063]

[0064]

[0065] As can be seen from Table 1, the road asphalt prepared by blending vacuum residue oil with colloid and asphaltene as raw materials in a certain ratio in the present invention meets the quality index of standard JTGF40-2004 road petroleum asphalt 70A.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing high-grade road asphalt, characterized in that: The method comprises the following two steps: (1) subjecting vacuum residue to primary extraction through a solvent deasphalting process to obtain an asphaltene phase and an oil phase, the asphaltene phase is subjected to a solvent removal treatment to obtain an asphaltene component, the oil phase is subjected to secondary extraction and separation to obtain a deasphalted oil solution and a colloid solution, the colloid solution is subjected to a solvent removal treatment to obtain a colloid component, wherein the solvent used in the solvent deasphalting process is at least one of butane and pentane; (2) mixing the asphaltenes, colloids and vacuum residue obtained in step (1) to obtain the high-grade road asphalt; In the step (2), the mass ratio of asphaltene, colloid and vacuum residue is asphaltene: colloid: vacuum residue = (3-13): (5.1-6.9): (10-67); the extraction temperature of the primary extraction is 105-135°C; the oil phase is preheated to 125-145°C before the secondary extraction, and the extraction temperature of the secondary extraction is 125-145°C; the colloid solution is preheated to 250-288°C before steam stripping, and the steam stripping pressure of the colloid solution is 0.66-0.76MPa.

2. The method for preparing high-grade road asphalt according to claim 1, characterized in that: In the step (1), the asphaltene phase and the colloid solution are separated and butane is recovered by steam stripping, and the oil phase is subjected to secondary extraction in a colloid settler.

3. The method for preparing high-grade road asphalt according to claim 1, characterized in that: The weight ratio of butane to the vacuum residue oil of the extraction raw material in step (1) is 2.5-3.5:

1.

4. The method for preparing high-grade road asphalt according to claim 1, characterized in that: The asphaltene phase is preheated to 290-315° C. before steam stripping, and the asphaltene phase steam stripping pressure is 0.66-0.76 MPa.

5. The method for preparing high-grade road asphalt according to claim 1, characterized in that: The mixing temperature in step (2) is 150-220°C.

6. The method for preparing high-grade road asphalt according to claim 1, characterized in that: In the step (2), the asphaltene, colloid and vacuum residue are mixed in a static mixer; after the asphaltene, colloid and vacuum residue are mixed in the step (2), they are cooled to 120-160° C. by heat exchange.

7. A high-grade road asphalt prepared by the method for preparing high-grade road asphalt as claimed in claims 1 to 6.

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