Modified sludge pyrolysis residue and its application in preparation of modified asphalt mixture

Abstract

This invention provides modified sludge pyrolysis residue and its application in the preparation of modified asphalt mixtures. The method for preparing sludge pyrolysis residue for asphalt slurry involves mixing sludge with a modifier in a specific ratio and then pyrolyzing the mixture under anaerobic conditions at 500–800°C. The modifier is one or more of calcium oxide, calcium hydroxide, and flocculants. The sludge pyrolysis residue for asphalt slurry of this invention has fine particles, good mechanical properties, and excellent adhesion to the base asphalt. Applying sludge pyrolysis residue to asphalt slurry reduces the consumption of natural resources and provides an environmentally friendly and feasible means of resource recovery for sludge treatment.

Description

Technical Field

[0001] This invention relates to the field of environmental protection, specifically to modified sludge pyrolysis residue and its application in the preparation of modified asphalt mixtures. Background Technology

[0002] Currently, the amount of urban sewage sludge produced in production and daily life is increasing year by year. Sludge treatment occupies a large amount of space, generates dust, and negatively impacts the environment. Traditional sludge disposal methods mainly include landfill and incineration. Landfilling requires a large amount of land resources, has high site selection requirements, and is highly susceptible to secondary pollution problems such as groundwater pollution, air pollution, and the spread of pathogens. Incineration can quickly and effectively achieve the harmlessness and reduction of sludge volume, but it easily produces large amounts of fly ash flue gas containing toxic substances, which can easily cause secondary pollution to the environment. Moreover, flue gas treatment facilities are costly and difficult to implement. Therefore, the environmentally friendly and effective treatment of urban sewage sludge is an urgent problem to be solved. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the existing technology and provide modified sludge pyrolysis residue and its application in the preparation of modified asphalt mixtures.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for preparing pyrolysis residue of municipal sludge for asphalt slurry, the method comprising the following steps:

[0005] Urban sewage sludge is mixed with a modifier in a certain proportion and then pyrolyzed under high temperature and oxygen-free conditions.

[0006] The ratio of the amount of municipal sludge to the modifier is: the weight of the modifier is 6% to 15% of the weight of the dry municipal sludge.

[0007] The modifier is one or more of calcium oxide, calcium hydroxide, and flocculant; the flocculant is one or more of polyferric sulfate, polyacrylamide, and polyaluminum chloride.

[0008] The temperature of the high-temperature oxygen-free pyrolysis is 500–800℃.

[0009] The application of sewage sludge in the preparation of asphalt slurry has a significant impact on the properties of asphalt slurry due to the influence of raw materials, component ratios, and raw material properties. This influences the adhesion and viscoelasticity of the asphalt slurry, and consequently affects the high-temperature performance, low-temperature performance, water stability, and fatigue durability of the asphalt mixture. Raw materials used in asphalt slurry should at least negatively impact its properties, and ideally, improve them. Applying dried sewage sludge to asphalt slurry will negatively affect the high-temperature performance, low-temperature performance, water stability, and fatigue durability of the asphalt mixture. The aforementioned method for preparing asphalt slurry using municipal sewage sludge pyrolysis residue is based on the harmless treatment of sewage sludge using high-temperature anaerobic pyrolysis technology. Because the pyrolysis reaction occurs in an anaerobic environment, nutrients and fixed carbon in the sewage sludge are retained in the pyrolysis residue, and the complete decomposition of easily perishable organic matter prevents the pyrolysis residue from emitting odor, laying the foundation for its subsequent resource utilization. The municipal sewage sludge pyrolysis residue prepared by the above method has fine particles, good mechanical properties, and good adhesion to the matrix asphalt. Applying sludge pyrolysis residue to asphalt slurry can reduce the consumption of natural resources and provide an environmentally friendly and feasible means of resource utilization for sludge treatment.

[0010] Preferably, the pyrolysis time under the high temperature and oxygen-free conditions is 0.8 to 1.5 hours.

[0011] Preferably, the temperature of the high-temperature oxygen-free pyrolysis is 600–700°C.

[0012] The above-mentioned method for preparing pyrolysis residue of municipal sludge for asphalt slurry, when the high-temperature anaerobic pyrolysis temperature is 600-700℃, results in asphalt slurry with better water stability and fatigue durability when the prepared pyrolysis residue is applied to asphalt slurry.

[0013] Preferably, the modifier is a mixture of calcium hydroxide and flocculant, with a weight ratio of calcium hydroxide to flocculant of (1.5-3.5):1, or the modifier is a mixture of calcium oxide and flocculant, with a weight ratio of calcium oxide to flocculant of (1.2-2.5):1, and the municipal sludge is at least one of sewage treatment plant sludge or water purification plant sludge.

[0014] The above-mentioned method for preparing municipal sludge pyrolysis residue for asphalt slurry shows that the application of modifiers significantly affects the properties of the prepared municipal sludge pyrolysis residue. After using the modifier, the prepared municipal sludge pyrolysis residue exhibits better water stability and fatigue durability when applied to asphalt slurry. Furthermore, when the modifier is a mixture of calcium hydroxide and flocculant, or a mixture of calcium oxide and flocculant, the asphalt slurry exhibits better temperature performance, water stability, and fatigue durability.

[0015] The present invention also provides urban sludge pyrolysis residue for asphalt slurry prepared by any of the above-described preparation methods.

[0016] The application of urban sludge pyrolysis residue to asphalt slurry can reduce the consumption of natural resources and provide an environmentally friendly and feasible means of resource utilization for sludge treatment.

[0017] The present invention also provides the application of the above-mentioned urban sludge pyrolysis residue for asphalt slurry in the preparation of asphalt slurry.

[0018] The present invention also provides an asphalt slurry, the asphalt slurry comprising the above-mentioned asphalt slurry-using municipal sludge pyrolysis residue, mineral powder, and asphalt.

[0019] The preparation method of the asphalt slurry is as follows: the graded mixture of the above-mentioned asphalt slurry, urban sludge pyrolysis residue and mineral powder mixed according to the gradation ratio is mixed into the asphalt in a molten and flowing state, stirred evenly, and then sheared at high speed at 3000-5000 rpm for 20-40 minutes. The asphalt is stirred at 200-400 rpm for 2-10 minutes to remove air bubbles.

[0020] Preferably, the mass ratio of the graded mixture to asphalt is (0.8–1.2):1;

[0021] Preferably, the temperature of the molten, flowing asphalt is 130–140°C.

[0022] Preferably, in the graded mixture, the weight ratio of the asphalt slurry pyrolysis residue from urban sludge to mineral powder is 1:(0.5-2).

[0023] The present invention also provides a method for preparing any of the above-described asphalt slurries, the method comprising the following steps:

[0024] (1) Heat the asphalt at 130-140℃ until it is in a molten and flowing state;

[0025] (2) The graded mixture of any of the above-mentioned asphalt slurry materials, namely, urban sludge pyrolysis residue and mineral powder, mixed according to the gradation ratio, is mixed into the asphalt in a molten flow state.

[0026] (3) After mixing evenly, shear at high speed for 20 to 40 minutes at a speed of 3000 to 5000 rpm;

[0027] (4) Stir at 200-400 rpm for 2-10 minutes to remove air bubbles.

[0028] Preferably, the mass ratio of the graded mixture to asphalt is 1:1.

[0029] The beneficial effects of this invention are as follows: This invention provides modified sludge pyrolysis residue and its application in the preparation of modified asphalt mixtures. The preparation method of municipal sludge pyrolysis residue for asphalt slurry of this invention is based on the harmless treatment of sludge using high-temperature anaerobic pyrolysis technology. Because the sludge pyrolysis reaction process is carried out in an anaerobic environment, the nutrients and fixed carbon in the sludge are retained in the pyrolysis residue, and the complete decomposition of easily perishable organic matter prevents the pyrolysis residue from emitting odor, laying the foundation for the subsequent resource utilization of the pyrolysis residue. The municipal sludge pyrolysis residue for asphalt slurry of this invention has fine particles, good mechanical properties, and can adhere well to the matrix asphalt. The application of sludge pyrolysis residue to asphalt slurry can reduce the consumption of natural resources and provide an environmentally friendly and feasible resource utilization method for sludge treatment. Detailed Implementation

[0030] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0031] Example 1

[0032] As a method for preparing municipal sludge pyrolysis residue for asphalt slurry according to the present invention, the method includes the following steps:

[0033] (1) The municipal sludge from the sewage treatment plant is mixed with a modifier in a certain proportion, wherein the weight of the modifier is 8% of the weight of the dry municipal sludge; the modifier is calcium oxide and polyferric sulfate in a weight ratio of 2:1.

[0034] (2) Pyrolysis at 500℃ under oxygen-free conditions for 1 hour.

[0035] Example 2

[0036] As a method for preparing municipal sludge pyrolysis residue for asphalt slurry according to the present invention, the method includes the following steps:

[0037] (1) The municipal sludge from the sewage treatment plant is mixed with a modifier in a certain proportion, wherein the weight of the modifier is 8% of the weight of the dry municipal sludge; the modifier is calcium hydroxide and polyacrylamide in a weight ratio of 2:1.

[0038] (2) Pyrolysis at 600℃ under oxygen-free conditions for 1 hour.

[0039] Example 3

[0040] As a method for preparing municipal sludge pyrolysis residue for asphalt slurry according to the present invention, the method includes the following steps:

[0041] (1) The municipal sludge from the sewage treatment plant is mixed with a modifier in a certain proportion, wherein the weight of the modifier is 8% of the weight of the dry municipal sludge; the modifier is calcium oxide and polyaluminum chloride in a weight ratio of 2:1.

[0042] (2) Pyrolysis at 700℃ under oxygen-free conditions for 1 hour.

[0043] Example 4

[0044] As a method for preparing municipal sludge pyrolysis residue for asphalt slurry according to the present invention, the method includes the following steps:

[0045] (1) The municipal sludge from the sewage treatment plant is mixed with a modifier in a certain proportion, wherein the weight of the modifier is 8% of the weight of the dry municipal sludge; the modifier is calcium oxide.

[0046] (2) Pyrolysis at 800℃ under oxygen-free conditions for 1 hour.

[0047] Example 5

[0048] As a method for preparing municipal sludge pyrolysis residue for asphalt slurry according to the present invention, the method includes the following steps:

[0049] (1) The municipal sludge from the sewage treatment plant is mixed with a modifier in a certain proportion, wherein the weight of the modifier is 8% of the weight of the dry municipal sludge; the modifier is a mixture of calcium oxide and flocculant; the weight ratio of calcium oxide to flocculant is 1.5:1, and the flocculant is a mixture of ferric chloride and polyacrylamide in a mass ratio of 2:1.

[0050] (2) Pyrolysis at 600℃ under oxygen-free conditions for 1 hour.

[0051] Example 6

[0052] As a method for preparing municipal sludge pyrolysis residue for asphalt slurry according to the present invention, the method includes the following steps:

[0053] (1) The municipal sludge from the sewage treatment plant is mixed with the modifier in a certain proportion, wherein the weight of the modifier is 8% of the weight of the dry municipal sludge; the modifier is a mixture of calcium hydroxide and flocculant; the weight ratio of calcium hydroxide to flocculant is 1.5:1, and the flocculant is a mixture of polyferric sulfate and polyaluminum chloride in equal mass ratio.

[0054] (2) Pyrolysis at 600℃ under oxygen-free conditions for 1 hour.

[0055] Example 7

[0056] As an asphalt slurry of the present invention, the asphalt slurry comprises the above-mentioned asphalt slurry pyrolysis residue of urban sludge, mineral powder, and asphalt.

[0057] The preparation method of the asphalt slurry in this embodiment includes the following steps:

[0058] (1) Heat the asphalt at 135℃ for 1 hour until it reaches a molten and flowing state;

[0059] (2) Mix the asphalt slurry with the pyrolysis residue of urban sludge and mineral powder in a weight ratio of 1:1 and mix it into the molten and flowing asphalt; the total weight ratio of the asphalt slurry with the pyrolysis residue of urban sludge and mineral powder to the weight ratio of asphalt is 1:1.

[0060] (3) After mixing evenly, shear at high speed for 30 minutes at a speed of 4000 rpm;

[0061] (4) Stir at 300 rpm for 5 minutes until air bubbles are removed.

[0062] The pyrolysis residue of municipal sludge used for asphalt slurry in step (2) above are the pyrolysis residues of municipal sludge used for asphalt slurry obtained by the preparation methods of Examples 1-6. Using the above 6 different pyrolysis residues of municipal sludge used for asphalt slurry, 6 kinds of asphalt slurry were prepared according to the asphalt slurry preparation method of Example 7, and are respectively referred to as Example 1, Example 2, Example 3, Example 4, Example 5, and Example 6.

[0063] Example 8

[0064] As an asphalt slurry of the present invention, the asphalt slurry comprises the above-mentioned asphalt slurry pyrolysis residue of municipal sludge, mineral powder, calcium oxide and asphalt.

[0065] The preparation method of the asphalt slurry in this embodiment includes the following steps:

[0066] (1) Heat the asphalt at 135℃ for 1 hour until it reaches a molten and flowing state;

[0067] (2) Mix the asphalt slurry with the pyrolysis residue of urban sludge, mineral powder and calcium oxide in a weight ratio of 1:1:1 and mix it into the molten and flowing asphalt; the total weight ratio of the asphalt slurry with the pyrolysis residue of urban sludge, calcium oxide and mineral powder to the weight ratio of asphalt is 1:1.

[0068] (3) After mixing evenly, shear at high speed for 30 minutes at a speed of 4000 rpm;

[0069] (4) Stir at 300 rpm for 5 minutes until air bubbles are removed.

[0070] The pyrolysis residue of urban sludge used for asphalt slurry in step (2) above is the pyrolysis residue of urban sludge used for asphalt slurry in Example 5.

[0071] Comparative Example 1

[0072] As a comparative example of the present invention, a method for preparing municipal sludge pyrolysis residue for asphalt slurry includes the following steps:

[0073] (1) The municipal sludge from the sewage treatment plant is mixed with a modifier in a certain proportion, wherein the weight of the modifier is 8% of the weight of the dry municipal sludge; the modifier is calcium oxide.

[0074] (2) Pyrolysis in air at 600℃ for 1 hour.

[0075] The asphalt slurry in this comparative example was prepared by replacing the pyrolysis residue of urban sludge in Example 7 with the asphalt slurry, and the asphalt slurry was prepared in the same way and proportion.

[0076] Comparative Example 2

[0077] As a comparative example of the present invention, a method for preparing municipal sludge pyrolysis residue for asphalt slurry includes the following steps:

[0078] (1) Pyrolyze the urban sludge from the sewage treatment plant at 600℃ under anaerobic conditions for 1 hour.

[0079] The asphalt slurry in this comparative example was prepared by replacing the pyrolysis residue of urban sludge in Example 7 with the asphalt slurry, and the asphalt slurry was prepared in the same way and proportion.

[0080] Comparative Example 3

[0081] As a comparative example of the present invention, asphalt slurry was prepared by replacing the asphalt slurry made from the pyrolysis residue of the municipal sludge in Example 7 with municipal sludge dried at 100°C, and then prepared according to the same method and proportion.

[0082] Comparative Example 4

[0083] As a comparative example of the present invention, the asphalt slurry comprises dried sludge, mineral powder, calcium oxide, and asphalt. The dried sludge is obtained by drying urban sludge from a sewage treatment plant at 100°C.

[0084] The preparation method of the asphalt slurry in this comparative example includes the following steps:

[0085] (1) Heat the asphalt at 135℃ for 1 hour until it reaches a molten and flowing state;

[0086] (2) Mix dried sludge, mineral powder and calcium oxide in a weight ratio of 1:1:1 and mix them into the molten and flowing asphalt; the total weight ratio of dried sludge, mineral powder and calcium oxide to the weight ratio of asphalt is 1:1.

[0087] (3) After mixing evenly, shear at high speed for 30 minutes at a speed of 4000 rpm;

[0088] (4) Stir at 300 rpm for 5 minutes until air bubbles are removed.

[0089] Comparative Example 5

[0090] As a comparative example of the present invention, the asphalt slurry comprises mineral powder and asphalt, wherein the weight ratio of mineral powder to asphalt is 1:1.

[0091] Experimental methods

[0092] I. Raw Materials

[0093] 1. Asphalt

[0094] The asphalt binder uses 70# base asphalt, and its main technical specifications are shown in the table below. Asphalt Technical Performance Indicators.

[0095]

[0096] 2. Mineral powder

[0097] The mineral powder is limestone mineral powder. The test requirements are in accordance with Article 4.10 of the "Technical Specification for Construction of Asphalt Pavement of Highway" JTG F40-2004. The mineral powder should meet the technical indicators required in the design specifications. The test procedure is in accordance with the "Test Procedure for Aggregates of Highway Engineering" JTG E42-2005. The specific performance indicators are shown in the table below.

[0098]

[0099] II. Testing of Asphalt Slurry Properties

[0100] The three major index tests were conducted in accordance with T0606-2011 of the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011).

[0101] (a) Softening point, penetration and ductility tests.

[0102] The initial temperature was 5℃, and the heating rate was 5℃ / min. The softening point can evaluate the temperature stability of asphalt to a certain extent. The penetration test was conducted at a test temperature of 25℃ and a penetration time of 5s to test the penetration of modified asphalt and evaluate the effect of fly ash on asphalt penetration under different substitution amounts. The ductility test was conducted at a test temperature of 15℃ and a tensile speed of 5cm / min to evaluate the low-temperature crack resistance of fly ash asphalt mastic. The instruments used for the softening point, penetration, and ductility tests were an asphalt softening point tester (WSY-025F), a fully automatic asphalt penetration tester (WSY-026C), and a temperature- and speed-adjustable asphalt ductility tester (LYY-10A), respectively.

[0103] The experimental results are shown in Table 1:

[0104] Table 1 Softening point, penetration, and ductility of asphalt grout

[0105] sample Softening point (°C) Penetration (mm) Ductility (cm) Example 1 66.01 2.38 3.6 Example 2 68.39 2.30 3.6 Example 3 69.80 2.25 3.5 Example 4 68.66 2.37 3.6 Example 5 69.11 2.36 3.6 Example 6 68.99 2.39 3.6 Example 8 68.80 2.36 3.5 Comparative Example 1 63.57 2.54 3.7 Comparative Example 2 61.96 2.62 3.6 Comparative Example 3 60.77 2.67 3.3 Comparative Example 4 62.80 2.56 3.2 Comparative Example 5 58.10 2.72 3.6

[0106] The experimental results show that the softening point of the asphalt slurry in the examples is higher than that in the comparative examples. The application of the pyrolysis residue of municipal sludge prepared in this invention to asphalt slurry can improve its high-temperature resistance. Furthermore, comparing the results of Examples 1-7 with those of Comparative Examples 1-2, the softening point of the asphalt slurry in Examples 1-7 is higher than that in Comparative Examples 1-2. This indicates that the pyrolysis residue of municipal sludge used in asphalt slurry needs to be prepared under modified and oxygen-free conditions to improve the high-temperature resistance of the asphalt slurry.

[0107] The experimental results show that the penetration of the asphalt slurry in the embodiment is lower than that in the comparative example. The application of the asphalt slurry prepared by this invention to pyrolysis residue of municipal sludge can improve the viscosity of the asphalt slurry and promote asphalt hardening.

[0108] The experimental results show that the ductility of the asphalt slurry in the embodiment is similar to that in the comparative example. However, the application of the asphalt slurry prepared in this invention using pyrolysis residue from municipal sludge may affect the low-temperature crack resistance of the asphalt slurry.

[0109] (II) Dynamic Shear Rheometer (DSR)

[0110] Dynamic shear rheometer (DSR) testing is the most commonly used test method for evaluating the high-temperature rheological properties of asphalt binders. The rutting factor G* / sinδ, complex modulus G*, and phase angle δ are important technical parameters in the Superpave test, characterizing the asphalt binder's resistance to high-temperature permanent deformation and its viscoelasticity. These parameters allow for in-depth research into the medium- and high-temperature properties of asphalt binders. A larger rutting factor G* / sinδ indicates more significant elastic properties of the asphalt. The complex shear modulus G* reflects the asphalt's resistance to deformation under repeated shear stress; a larger G* indicates stronger resistance to deformation, encompassing both elastic and viscous components. The phase angle δ is a relative indicator of the elastic and viscous components of the asphalt binder. This test used a Smart Pave 102 asphalt rheometer. The maximum torsional torque was 200 nNm, the minimum torque in rotation mode was 5 nNm, and the minimum torque in oscillation mode was 7.5 nNm. The test started at an initial temperature of 40℃, using a 25mm oscillating plate at 10 rad / s.

[0111] The test results of the rutting factor G* / sinδ are shown in Table 2. The rutting resistance of the embodiment is better than that of the comparative example. This indicates that the application of the pyrolysis residue of municipal sludge prepared in this invention to asphalt slurry can improve the rutting resistance of the asphalt slurry.

[0112] Table 2 Rutting factor of asphalt slurry G* / sinδ

[0113] temperature 40 46 52 58 64 70 76 82 Example 1 360286 112164 39864.9 18688.15 7233.58 3238.39 1618.6 951.15 Example 2 443042.72 143515.99 48380.19 21524.06 7781.81 3720.54 1824.85 1022.13 Example 3 462927.54 155448.31 48659.42 22728.57 8302.07 4386.11 1825.16 1026.93 Example 4 425349.59 133534.86 44728.89 20108.72 7269.96 3757.62 1695.05 977.17 Example 5 467491.27 166646.98 46732.67 22123.74 8889.75 4293.27 1811.23 998.17 Example 6 432815.98 131196.4 45345.77 20569.04 7297.66 3777.83 1744.01 910.09 Example 8 414509.62 149604.43 41822.58 20298.43 7582.33 3683.79 1735.42 843.33 Comparative Example 1 289845.17 94070.35 31000.08 14820.75 5691.67 2430.59 1288.02 743.59 Comparative Example 2 261964.09 76218.91 28388.64 9608.99 4662.54 1894.08 1052.79 613 Comparative Example 3 279847.86 91738.61 29466.33 10288.12 4929.49 2317.97 1311.4 716.25 Comparative Example 4 276125.29 90828.53 32260.28 12217.71 5625.14 2492.22 1144.57 714.44 Comparative Example 5 273606.59 84886.24 29076.65 10942.35 4469.43 2019.03 1015.52 562.66

[0114] (III) Rutting Test

[0115] The rutting test of asphalt mixtures was conducted according to the T0719-2011 standard of the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011). The test temperature was 60℃, and the wheel pressure was 0.7MPa. The deformation of the rutted pavement, d1 and d2, after 45 min and 60 min respectively, was obtained using the instrument, and the dynamic stability DS was calculated according to the following formula. The rutting test is the most important indicator in the performance testing of asphalt mixtures. Among them, dynamic stability can well reflect the ability of asphalt pavement to resist permanent deformation in high-temperature seasons. The rutting test instrument was a dynamic rutting test apparatus (WSY-078).

[0116]

[0117] Where: DS—dynamic stability of asphalt mixture (cycles / mm)

[0118] d1—The amount of deformation (mm) corresponding to time t1;

[0119] d2 — Deformation amount (mm) corresponding to time t2;

[0120] C1—Testing machine type coefficient, 1.0 for crank-connecting rod driven loading wheel reciprocating operation mode;

[0121] C2—Specimen coefficient, 1.0 for laboratory-prepared specimens with a width of 300 mm;

[0122] N—the reciprocating rolling speed of the test wheel, typically 42 times / min.

[0123] (iv) Marshall test under immersion

[0124] The tests were conducted according to the T0709-2011 standard Marshall stability test and the immersion Marshall stability test for asphalt mixtures in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011). The specimen insulation temperature was 60±1℃, with the insulation time for standard Marshall specimens being 30-40 min and the insulation time for immersion Marshall specimens being 48 h. The deformation at the maximum load was taken as the flow value (FL), and the maximum load was taken as the stability (MS). The Marshall modulus and residual stability of the specimens were calculated using the following formulas. The immersion Marshall stability test can verify the water damage resistance of asphalt mixtures. The immersion Marshall test instrument was an automatic Marshall stability tester (WSY-101).

[0125]

[0126] Where: T—Marshall modulus of the specimen (KN / mm);

[0127] MS—Stability of the specimen (KN);

[0128] FL—Flow value of the specimen (mm).

[0129]

[0130] Where: MS0—residual stability of the specimen after immersion in water (%);

[0131] MS—Stability of the specimen after immersion in water for 48 hours (KN).

[0132] The experimental results are shown in Table 3:

[0133] Table 3 Properties of Asphalt Slurry

[0134]

[0135]

[0136] As shown in Table 3, the dynamic stability of the embodiments is better than that of the comparative examples. This indicates that the application of the asphalt slurry prepared by the present invention using municipal sludge pyrolysis residue can improve the dynamic stability of the asphalt slurry.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing pyrolysis residue of municipal sludge for asphalt slurry, characterized in that, The method includes the following steps: Urban sewage sludge is mixed with a modifier in a certain proportion and then pyrolyzed under high temperature and oxygen-free conditions. The ratio of the amount of municipal sludge to the modifier is as follows: the weight of the modifier is 6% to 15% of the weight of the dry municipal sludge. The modifier is a mixture of calcium oxide and flocculant, with a weight ratio of calcium oxide to flocculant of (1.2~2.5):

1. The flocculant is one or more of polyferric sulfate, polyacrylamide, and polyaluminum chloride. The temperature of the high-temperature oxygen-free pyrolysis is 500~800℃, and the pyrolysis time under the high-temperature oxygen-free conditions is 0.8~1.5 hours.

2. The method for preparing municipal sludge pyrolysis residue for asphalt slurry according to claim 1, characterized in that, The temperature of the high-temperature anaerobic pyrolysis is 600~700℃, and the urban sludge is at least one of sewage treatment plant sludge or water purification plant sludge.

3. The pyrolysis residue of municipal sludge for asphalt slurry prepared by any one of the preparation methods described in claims 1-2.

4. The application of the pyrolysis residue of municipal sludge as described in claim 3 in the preparation of asphalt slurry.

5. An asphalt slurry, characterized in that, The asphalt slurry comprises, as described in claim 3, municipal sludge pyrolysis residue, mineral powder, and asphalt. The preparation method of the asphalt slurry is as follows: the graded mixture of urban sludge pyrolysis residue and mineral powder as described in claim 3, mixed according to the graded ratio, is mixed into the asphalt in a molten and flowing state. After stirring evenly, the mixture is sheared at a high speed of 3000~5000 rpm for 20~40 minutes, and the asphalt is stirred at 200~400 rpm for 2~10 minutes to remove air bubbles. The mass ratio of the graded mixture to asphalt is (0.8~1.2):1; The temperature of the asphalt in the molten flow state is 130~140℃.

6. The asphalt slurry according to claim 5, characterized in that, In the graded mixture, the weight ratio of the pyrolysis residue of municipal sludge and mineral powder used in the asphalt slurry as described in claim 3 is 1:(0.5~2).

7. The method for preparing asphalt slurry as described in claim 5 or 6, characterized in that, The method includes the following steps: (1) Heat the asphalt to 130~140℃ until it is in a molten and flowing state; (2) The graded mixture of municipal sludge pyrolysis residue and mineral powder as described in claim 3, mixed according to the graded ratio, is mixed into the asphalt in a molten flow state; (3) After mixing evenly, shear at high speed for 20-40 minutes at a speed of 3000-5000 rpm; (4) Stir at 200-400 rpm for 2-10 minutes to remove air bubbles.

8. The preparation method according to claim 7, characterized in that, The mass ratio of the graded mixture to asphalt is 1:1.

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