A method for producing hard road asphalt

Abstract

The application discloses a production method of hard road asphalt. The method comprises the following steps: (1) ethylene tar is subjected to reduced pressure distillation to obtain light components and heavy components, wherein the light components are used as extraction solvents; (2) the heavy components obtained in the step (1) are subjected to oxidation treatment to obtain an oxidation-treated mixture; (3) the oxidation-treated mixture obtained in the step (2) and a modifier are subjected to countercurrent contact with the extraction solvents to perform supercritical extraction, and the obtained raffinate heavy components are used as hard asphalt. The method is used for preparing No. 15 hard road asphalt by taking ethylene tar as raw material, can realize high-value utilization of the ethylene tar, and the obtained hard road asphalt has better high-temperature and low-temperature performances.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for preparing hard pitch from ethylene tar, belonging to the field of high value-added utilization of low-value resources. BACKGROUND

[0002] Hard pitch has small penetration and high softening point, and is used to improve the modulus of asphalt concrete and the high-temperature deformation resistance, and is also called high modulus asphalt in foreign countries. No. 15 hard pitch is mainly used to produce high modulus fatigue resistant asphalt mixture (HFM), which can effectively reduce the deformation of pavement under vehicle load, improve the high-temperature deformation resistance of pavement, and improve the fatigue resistance of pavement and prolong the service life of pavement.

[0003] However, the low-temperature anti-cracking performance of hard road pitch is poor, and it is difficult to balance the high-temperature anti-rutting performance, and there is a contradictory relationship between the two. On the basis of maintaining high-temperature performance, optimizing low-temperature performance is a technical problem to be solved in the research and development of hard road pitch at present. At present, many research units try to use No. 50 or No. 30 low-grade road pitch, and add lake pitch, rock pitch, high modulus additive or anti-rutting agent to start the research on high modulus asphalt mixture technology, but most of the hard pitch is prepared by simple blending and modification method, and the properties are unstable, the difference is large, and the low-temperature performance and fatigue resistance of the asphalt binder are often sacrificed. In addition, other modifiers such as SBS and rubber powder are used to modify the asphalt binder to improve the high and low temperature performance and fatigue performance, but the high production cost of the modifier still affects the large-area popularization and application of the new road material at present.

[0004] Peng Yu (Preparation and application of hard pitch special for high modulus asphalt mixture [D]. Chang'an University, 2014.) et al. prepared hard pitch by composite modification process, which has good high-temperature performance and low-temperature anti-cracking performance, and is suitable for northern areas with high low-temperature anti-cracking and fatigue resistance. CN104650602A discloses a high-grade road hard pitch and a preparation method thereof, which uses deoiled pitch, head oil slurry, extracted oil and SBS, SBR and other polymer modifiers to prepare high-grade road hard pitch with a penetration of 10-60 1 / 10mm. The above methods still need to be further improved in terms of cost performance, high and low temperature performance, and the production cost is high.

[0005] Ethylene tar is a by-product produced in the high-temperature condensation process of raw materials during the production of ethylene, which is about 15% of the ethylene yield. Due to the lack of awareness of the use of low-quality resources in the past, ethylene tar is only used as fuel oil for combustion, causing great waste of resources, so reasonable use of ethylene tar to produce hard pitch has good application prospect. SUMMARY

[0006] In view of the deficiencies in the prior art, the present application provides a production method of hard road asphalt. The method is to prepare No. 15 hard road asphalt from ethylene tar as raw material, which can realize high value-added utilization of ethylene tar, and the obtained hard road asphalt has better high temperature and low temperature performance.

[0007] The present application provides a production method of hard road asphalt, comprising the following steps:

[0008] (1) The ethylene tar is subjected to vacuum distillation to obtain light components and heavy components, wherein the light components are used as extraction solvents;

[0009] (2) The heavy components obtained in step (1) are subjected to oxidation treatment to obtain a mixture after oxidation treatment;

[0010] (3) The mixture after oxidation treatment obtained in step (2), a modifier and the extraction solvents are subjected to countercurrent contact for supercritical extraction, and the obtained raffinate heavy components are used as hard asphalt.

[0011] In the method of the present application, the ethylene tar has the following properties: a density of 1.0-1.2 g / cm 3 at 25℃, a carbon residue value of 12wt%-20wt%, and a mass content of aromatic hydrocarbons of 70wt% or more.

[0012] In step (1) of the method of the present application, in the vacuum distillation, the bottom temperature is 180-230℃, the top temperature is 120-150℃, and the fractionation pressure is 20-50kPa(A).

[0013] In step (2) of the method of the present application, the oxidation treatment uses an oxygen-containing gas as the oxidation gas, and the oxygen-containing gas has an oxygen volume content of 15% or more, such as air. The flow rate of the oxygen-containing gas is 5-20L / min / 100kg of heavy components.

[0014] In step (2) of the method of the present application, the oxidation treatment is performed at a temperature of 200-300℃.

[0015] In step (2) of the method of the present application, the oxidation treatment is performed for a time of 50-100min.

[0016] In step (3) of the method of the present application, the modifier is at least one of diphenylamine or phenylenediamine and derivatives thereof (preferably at least one of N,N'-diphenyl-1,4-phenylenediamine, N-nitrosodiphenylamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, and N-phenyl-N'-cyclohexyl-p-phenylenediamine). The mass ratio of the modifier to the treated mixture obtained in step (2) is 0.1-1:100.

[0017] In the method, in step (3), the volume ratio of the extraction solvent to the treated mixture obtained in step (2) is 3-6:1.

[0018] In the method, in step (3), the temperature of the extraction is 200-300 DEG C, and the pressure is 4-6 MPa.

[0019] In the method, in step (3), the light component of the obtained extractant does not need to be separated by solvent and can be directly used as light tar.

[0020] In the method, the 25 DEG C penetration of the hard pitch is 10-20 0.1 mm; the softening point is greater than or equal to 75 DEG C; the dynamic viscosity at 60 DEG C is greater than 5000 Pa s; and the 25 DEG C ductility before film formation is greater than or equal to 30 cm.

[0021] Compared with the prior art, the method has the following beneficial effects:

[0022] 1. The method uses ethylene tar as raw material, the raw material is widely available and low in price, the hard road pitch produced has excellent high and low temperature performance, and high value-added utilization of low value resources is realized.

[0023] 2. In the method, the ethylene tar is first subjected to vacuum distillation, then the heavy component is subjected to short-time oxidation treatment, under the action of oxygen, the tar molecules are subjected to oxidative crosslinking and dehydrogenation condensation, the unsaturated bonds and small molecule aromatic hydrocarbons are converted into condensed ring aromatic hydrocarbons, the modified agent is added to the mixture after oxidation treatment, and the light component of the ethylene tar is used as the extraction solvent to perform supercritical extraction, on the one hand, the free radicals generated in the oxidation process are eliminated, and the formed pitch system is stabilized, on the other hand, the residual light component in the system is separated out, the ethylene tar molecules are moderately polymerized, and the obtained hard pitch has a higher softening point, better low temperature ductility and more excellent aging resistance.

[0024] 3. Different from conventional supercritical extraction, the light component of the ethylene tar is used as the extraction solvent in the method, the extraction efficiency is higher, the prepared hard pitch has more excellent high temperature performance, the solvent as part of the light tar does not need to be separately recovered, and the process is more energy-saving. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The figure is a flowchart of the method;

[0026] The figure is a flowchart of the method; DETAILED DESCRIPTION

[0027] The technical solutions of the present application are further illustrated in connection with the following examples, but are not limited to the following examples.

[0028] The technical solutions of the present application are further illustrated in connection with the following examples, but are not limited to the following examples. Figure 1 The technical solutions of the present application are further illustrated in connection with the following examples, but are not limited to the following examples. The present application provides a production method of hard road asphalt, which comprises: ethylene tar 5 enters a fractionating tower 1 for fractionation to obtain light components 6 and heavy components 7, wherein the light components 6 are used as solvents of an extraction tower 3, the solvents do not need to be recycled, the heavy components 7 enter an oxidation treatment tower 2 together with an oxygen-containing gas 8 for reaction, a gas 9 is discharged from the top of the oxidation treatment tower, an oxidation-treated mixture 10 discharged from the bottom of the tower, a modifier 11 and an extraction solvent 14 are countercurrently contacted in the extraction tower 3 for extraction, and a raffinate heavy component 12 obtained is used as hard road asphalt, and an extract light component 13 is used as light tar.

[0029] Test method of related parameters of the present application:

[0030] The penetration and the penetration index PI are determined according to the standard T0604 of the Ministry of Communications, the softening point (ring and ball method) is determined according to the standard T0606 of the Ministry of Communications, the ductility is determined according to the standard T0605 of the Ministry of Communications, the thin film heating test (TFOT) is carried out according to the standard T0609 of the Ministry of Communications, and the asphalt dynamic viscosity test is carried out according to the standard T0620 of the Ministry of Communications.

[0031] Example 1

[0032] This example adopts the process as shown in Figure 1 , the modifier is diphenylamine, and the properties of the ethylene tar are shown in Table 1. The ethylene tar enters a fractionating tower, the bottom temperature of the tower is 220℃, the top temperature of the tower is 130℃, the fractionating pressure is 40kPa(A), the light components at the top of the tower are used as solvents of an extraction tower, the heavy components at the bottom of the tower enter an oxidation treatment tower together with air for reaction, the gas flow rate is 13L / min / 100kg of the heavy components, the temperature in the tower is 250℃, and a mixture is obtained after the treatment for 50min. The oxidation-treated mixture and the modifier enter an extraction tower at a mass ratio of 100:0.4, and are countercurrently contacted with an extraction solvent for supercritical extraction, the extraction conditions are as follows: the extraction temperature is 210℃, the extraction pressure is 5MPa, the volume ratio of the extraction solvent to the oxidation-treated material is 5:1, and the raffinate heavy component obtained after the extraction is used as hard asphalt, and the properties are shown in Table 2. The extract light component obtained does not need to be separated from the solvent, and is used as light tar.

[0033] Example 2

[0034] This example adopts the process as shown in Figure 1The process involves using phenylenediamine as the modifier, and the properties of ethylene tar are shown in Table 1. Ethylene tar enters a fractionation tower with a bottom temperature of 200℃, a top temperature of 120℃, and a fractionation pressure of 30 kPa(A). The light fraction at the top is used as the solvent in the extraction tower, while the heavy fraction at the bottom reacts with air in an oxidation treatment tower at a gas flow rate of 10 L / min / 100 kg of heavy fraction and a tower temperature of 260℃. After 60 min, a mixture is obtained. The oxidized mixture and the modifier are then introduced into the extraction tower at a mass ratio of 100:0.5, where they undergo supercritical extraction in countercurrent contact with the extraction solvent. The extraction conditions are as follows: extraction temperature 210℃, pressure 4.5 MPa, and a volume ratio of extraction solvent to oxidized material of 4:1. The heavy fraction of the raffinate obtained after extraction is used as hard asphalt, and its properties are shown in Table 2. The light fraction of the extract does not require solvent separation and is used as light tar.

[0035] Example 3

[0036] This example uses the following... Figure 1 The process involved using diphenylamine as the modifier. The properties of ethylene tar are shown in Table 1. Ethylene tar entered a fractionation tower with a bottom temperature of 210℃, a top temperature of 130℃, and a fractionation pressure of 20 kPa(A). The light fraction at the top was used as the solvent in the extraction tower, while the heavy fraction at the bottom reacted with air in an oxidation treatment tower at a gas flow rate of 18 L / min / 100 kg of heavy fraction and a tower temperature of 220℃. After 70 min, a mixture was obtained. The oxidized mixture and the modifier were then fed into the extraction tower at a mass ratio of 100:0.3, where they were subjected to supercritical extraction in countercurrent contact with the extraction solvent. The extraction conditions were as follows: extraction temperature 240℃, pressure 4 MPa, and a volume ratio of extraction solvent to oxidized material of 3:1. The heavy fraction of the raffinate obtained after extraction was used as hard asphalt, and its properties are shown in Table 2. The light fraction of the extract did not require solvent separation and was used as light tar.

[0037] Example 4

[0038] This example uses the following... Figure 1 The process involves using phenylenediamine as the modifier, and the properties of ethylene tar are shown in Table 1. Ethylene tar enters a fractionation tower with a bottom temperature of 200℃, a top temperature of 120℃, and a fractionation pressure of 40 kPa(A). The light fraction at the top is used as the solvent in the extraction tower, while the heavy fraction at the bottom reacts with air in an oxidation treatment tower at a gas flow rate of 7 L / min / 100 kg of heavy fraction and a tower temperature of 270℃. After 60 min, a mixture is obtained. The oxidized mixture and the modifier are then introduced into the extraction tower at a mass ratio of 100:0.6, where they undergo supercritical extraction in countercurrent contact with the extraction solvent. The extraction conditions are as follows: extraction temperature 250℃, pressure 5 MPa, and a volume ratio of extraction solvent to oxidized material of 4:1. The heavy fraction of the raffinate obtained after extraction is used as hard asphalt, and its properties are shown in Table 2. The light fraction of the obtained extract does not require solvent separation and is used as light tar.

[0039] Example 5

[0040] This example uses the process as shown in Figure 1 , the modifier is N-nitrosodiphenylamine, and the ethylene tar properties are shown in Table 1. The ethylene tar is fed into a fractionating column, the column bottom temperature is 230°C, the column top temperature is 150°C, the fractionating pressure is 40 kPa(A), the light component at the column top is used as the solvent for the extraction column, the heavy component at the column bottom is reacted with air in an oxidation treatment column, the gas flow rate is 10 L / min / 100 kg of the heavy component, the temperature in the column is 230°C, and after 60 minutes of treatment, a mixture is obtained. The mixture after oxidation is fed into the extraction column with the modifier at a mass ratio of 100:0.4, and is contacted countercurrently with the extraction solvent to perform supercritical extraction, the extraction conditions are as follows: the extraction temperature is 270°C, the pressure is 4 MPa, the volume ratio of the extraction solvent to the material after oxidation is 3:1, and after extraction, the raffinate heavy component is used as hard pitch, and the properties are shown in Table 2. The light component of the extractant obtained does not need to be separated by solvent, and is used as light tar.

[0041] Example 6

[0042] This example uses the process as shown in Figure 1 , the modifier is N,N'-diphenyl-1,4-phenylenediamine, and the ethylene tar properties are shown in Table 1. The ethylene tar is fed into a fractionating column, the column bottom temperature is 210°C, the column top temperature is 140°C, the fractionating pressure is 50 kPa(A), the light component at the column top is used as the solvent for the extraction column, the heavy component at the column bottom is reacted with air in an oxidation treatment column, the gas flow rate is 8 L / min / 100 kg of the heavy component, the temperature in the column is 250°C, and after 90 minutes of treatment, a mixture is obtained. The mixture after oxidation is fed into the extraction column with the modifier at a mass ratio of 100:0.7, and is contacted countercurrently with the extraction solvent to perform supercritical extraction, the extraction conditions are as follows: the extraction temperature is 250°C, the pressure is 5 MPa, the volume ratio of the extraction solvent to the material after oxidation is 4:1, and after extraction, the raffinate heavy component is used as hard pitch, and the properties are shown in Table 2. The light component of the extractant obtained does not need to be separated by solvent, and is used as light tar.

[0043] Comparative Example 1

[0044] Compared with Example 1, the difference is that no modifier diphenylamine is added. The results are shown in Table 3.

[0045] Comparative Example 2

[0046] Compared with Example 1, the difference is that the oxidation temperature is reduced to 150°C. The results are shown in Table 3.

[0047] Comparative Example 3

[0048] Compared with Example 1, the difference is that no supercritical extraction is performed, and the mixture after oxidation treatment is used as pitch product. The results are shown in Table 3.

[0049] Table 1 Ethylene tar properties

[0050] Analysis item Data Density at 25°C, g / cm 1.103 Kinematic viscosity at 60°C, cst 194.3 Carbon residue, % 16.31 Aromatic content, wt% 78.23 Ash content, % 0.034 Elemental composition, % C 92.56 H 7.30 S 0.05 N 0.03 O 0.06

[0051] Table 2 Product test results for each example

[0052]

[0053] Table 3 Product test results for each comparative example

[0054] Comparative example 1 Comparative example 2 Comparative example 3 Penetration (25°C) / 0.1 mm 5 25 34 Penetration index PI -0.96 -0.87 -0.93 Softening point / °C 84.5 61.3 53.0 Elongation (25°C) / cm 19.1 61.2 67.3 Kinematic viscosity at 60°C / Pa-s 7789 3401 2394 TFOT (5h) Needle ratio, % 75.0 64.0 70.5 Mass loss, % 0.05 0.12 0.11

[0055] The embodiments described herein are merely illustrative of the present application and do not limit the present application thereto. The present application can be implemented without the steps described in the above embodiments. In summary, any improvement made by those skilled in the art to the present application, as long as it does not deviate from the technical solution of the present application, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, all belong to the protection scope and disclosure scope of the present application.

Claims

1. A method for producing hard road asphalt, comprising the following steps: (1) subjecting ethylene tar to vacuum distillation to obtain light components and heavy components, wherein the light components are used as an extraction solvent; (2) subjecting the heavy components obtained in step (1) to oxidation treatment to obtain an oxidation-treated mixture; (3) subjecting the oxidation-treated mixture obtained in step (2) and a modifier to countercurrent contact with the extraction solvent to perform supercritical extraction, and using the obtained raffinate heavy components as hard road asphalt; In step (1), the vacuum distillation is performed at a bottom temperature of 180-230℃, a top temperature of 120-150℃, and a distillation pressure of 20-50 kPa(A); In step (2), the oxidation treatment is performed at a temperature of 200-300℃ for 50-100 min; In step (3), the modifier is at least one of diphenylamine or phenylenediamine and derivatives thereof; the mass ratio of the modifier to the treated mixture obtained in step (2) is 0.1-1:100; In step (3), the extraction is performed at a temperature of 200-300℃ and a pressure of 4-6 MPa; the volume ratio of the extraction solvent to the treated mixture obtained in step (2) is 3-6:

1.

2. The production method according to claim 1, characterized by, The ethylene tar has the properties of 1.0-1.2 g / cm3 of density at 25℃, 12-20 wt% of carbon residue value, and 70 wt% or more of mass content of aromatic hydrocarbon. 3 , 12-20 wt% of carbon residue value, and 70 wt% or more of mass content of aromatic hydrocarbon.

3. The production method according to claim 1, characterized by, In step (2), the oxidation treatment uses an oxygen-containing gas as an oxidation gas, and the oxygen-containing gas contains oxygen at a volume content of more than 15%.

4. The production method according to claim 3, characterized by, In step (2), the flow rate of the oxygen-containing gas is 5-20 L / min per 100 kg of heavy components.

5. The production method according to claim 1, characterized by, In step (3), the modifier is at least one of N,N'-diphenyl-1,4-phenylenediamine, N-nitrosodiphenylamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, and N-phenyl-N'-cyclohexyl-p-phenylenediamine.

6. The production method according to claim 1, characterized by, In step (3), the obtained extraction light components do not need to be subjected to solvent separation and can be directly used as light tar.

7. The production method according to claim 1, characterized by, The hard road asphalt has a 25℃ penetration of 10-20 0.1 mm, a softening point of ≥75℃, a dynamic viscosity at 60℃ of >5000 Pa·s, and a 25℃ pre-film ductility of ≥30 cm.

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