A binder asphalt and a method for producing the same

Abstract

The application discloses a kind of bonding asphalt and its preparation method.The bonding asphalt of the application includes the following components by weight parts: medium temperature coal pitch: 100 parts;Preprocessing ethylene tar: 5-20 parts;Preprocessing soapstock residue: 3-15 parts.The bonding asphalt of the application can meet the requirements of YB / T5194-2015 for secondary products, and has little harm to the environment and human body.

Description

Technical Field

[0001] This invention belongs to the field of special asphalt processing and production, and specifically relates to a bonding asphalt and its preparation method. Background Technology

[0002] Binding pitch, due to its high carbon content and excellent binding properties, is an important carbonaceous binder in the production of carbon products. Coal tar pitch is the best raw material for producing binders for various carbon materials, especially electrode materials; its quality directly affects the strength, thermal shock resistance, electrical conductivity, thermal conductivity, and other technical properties of carbon products.

[0003] Before 1970, medium-temperature coal tar pitch was the preferred binder. However, medium-temperature coal tar pitch has a low softening point, making it prone to melting and agglomeration, and its coking value is low. Electrodes obtained using it as a binder exhibit poor conductivity, oxidation resistance, and thermal stability, failing to meet the needs of the smelting industry. The increasingly stringent quality requirements for binder pitch in high-power and ultra-high-power graphite electrodes, high-quality large-size prebaked anodes, and other high-grade carbon material products have made it imperative to replace medium-temperature coal tar pitch with modified pitch as a binder.

[0004] In the early 1950s, industrialized countries began researching modified bitumen as an electrode binder. Major manufacturers include Nippon Steel Chemical, Mitsubishi Chemical, Rüttger (Germany), Alcoa (Canada), and Alcoa (America). Commonly used methods for producing modified bitumen for binders include vacuum flash distillation and high-temperature thermal polymerization. To produce higher-quality binder bitumen, researchers have conducted in-depth studies on coal tar pitch modification processes. Hitomi et al. modified binder bitumen for graphite electrodes using distillation methods, investigated factors affecting coke yield and bitumen softening point, and determined measures to improve bitumen quality. Furthermore, many countries possess patented technologies for the industrial production of modified bitumen. The Cherry-T (CT) process for producing modified bitumen, developed by Osaka Gas Co., Ltd. of Japan, can use low-grade products (such as coal tar, heavy diesel oil, and asphalt) as substitutes for coking coal and as economically viable and widely applicable carbon raw materials.

[0005] Prior to the 1980s, China's domestic carbon materials industry consistently used medium-temperature pitch as a binder. Its softening point and coking value after carbonization were relatively low, making it unsuitable for producing high-end carbon materials. The modern carbon materials industry has demanded the replacement of medium-temperature pitch binders. High-quality modified pitch binders, produced through appropriate processing based on medium-temperature pitch, are increasingly favored. Since the Guizhou Aluminum Plant introduced a prebaked anode production project requiring the use of modified pitch, over the past two decades, more than ten coking enterprises have piloted the production of modified pitch. Currently, modified pitch is being promoted and used in aluminum carbon production enterprises, and metallurgical carbon production enterprises are preparing to adopt modified pitch binders. The replacement of medium-temperature pitch with modified pitch as the binder for carbon materials production is an inevitable trend.

[0006] In China, the production of modified coal tar pitch generally adopts the high-temperature thermal polymerization method (atmospheric and pressurized, intermittent and continuous) designed by Anshan Coking and Refractory Materials Research Institute, using coal tar and medium-temperature coal tar pitch as raw materials. In addition, Ansteel Chemical Plant and Hebei Tangshan Koppers (China) Carbon Chemical Co., Ltd. use KOPPERS technology to produce modified pitch via flash evaporation, using high-temperature pitch and hard pitch as raw materials. With the need for upgrading coal tar pitch products in the carbon materials industry, the share of modified pitch replacing medium-temperature pitch in China's coal tar pitch production will continue to increase, and the development of high-quality modified pitch is the future direction of China's coal tar pitch production. However, thermal polymerization or flash evaporation treatments also significantly alter the structural properties of coal tar pitch, particularly the rheological properties of modified pitch, narrowing the suitable low-viscosity temperature range and making it more difficult to control the plasticity range. This affects the yield of carbon material molding, which is currently a difficulty for Chinese metallurgical carbon enterprises in promoting the use of modified pitch, and also a problem that urgently needs to be solved in the practical application of modified pitch binders.

[0007] During the carbonization process, coal tar pitch undergoes a series of complex pyrolysis and condensation reactions. Volatile light components are continuously released during heating, resulting in the emission of polycyclic aromatic hydrocarbons (PAHs), which have been proven to be highly toxic and carcinogenic. Furthermore, China's efforts to reduce overcapacity and meet environmental protection requirements, leading to the closure of numerous small coking plants, will result in a demand for medium-temperature coal tar pitch exceeding supply, thus driving up its price. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a bonding asphalt and its preparation method. The bonding asphalt of the present invention meets the requirements for Grade II products in YB / T5194-2015.

[0009] The first aspect of this invention provides a binding bitumen, comprising, by weight, the following components:

[0010] Medium-temperature coal tar pitch: 100 parts;

[0011] Pre-treated ethylene tar: 5-20 parts, preferably 5-15 parts;

[0012] Pre-treated soap residue: 3-15 parts, preferably 5-10 parts.

[0013] The main properties of the medium-temperature coal tar pitch include: C 82.13wt%–84.51wt%, H 6.26wt%–7.36wt%, O 6.45wt%–7.02wt%, N 2.49wt%–2.85wt%, S 0.06wt%–0.15wt%; softening point 78–84℃; toluene-insoluble content (TI) 5.61–6.34wt%; quinoline-insoluble content (QI) 0.58–1.03wt%; coking value (CV) not less than 6wt%, preferably 6–15wt%; and β-resin not less than 5.45wt%.

[0014] The pretreated ethylene tar is obtained by distilling ethylene tar and extracting the fraction at a temperature greater than 320°C.

[0015] The main properties of the ethylene tar include: saturated components of 0.1 wt%–2.6 wt%, aromatic components of 54 wt%–69 wt%, resins of 25 wt%–34 wt%, and asphaltenes of 0.5 wt%–4.1 wt%. The four-component analysis method is T0618-1993 Asphalt Chemical Component Test (Four-component Method). The residual carbon value is 11 wt%–15 wt%, the C / H molar ratio is 12–14, and the S / N molar ratio is 14–20. ar 45wt%–48wt%, H α 31wt%–35wt%, H β accounting for 14wt% to 16wt%, H γ It accounts for 4 wt% to 7 wt%.

[0016] The soap residue is the residue remaining after the extraction of fatty acids from soap residue, preferably the residue remaining after the extraction of fatty acids from cottonseed oil soap residue.

[0017] The main properties of the soap residue include: a penetration of 190–205 1 / 10 mm at 25°C, a softening point of 39–44°C, a flash point of not less than 245°C, a solubility (with trichloroethylene as the solvent) of not less than 99.9 wt%, a total content of asphaltenes and gums of not less than 45 wt%, a dynamic viscosity of 69.64–74.59 Pa·s at 60°C, a fatty acid content of 40–50 wt%, an unsaponifiable matter content of 10–15 wt%, and a free carbon content of 0.3–0.8 wt%.

[0018] The pretreated soap residue is the fraction obtained by distilling soap residue and cutting it at a temperature greater than 380°C.

[0019] A second aspect of the present invention provides a method for preparing the above-mentioned bonding bitumen, comprising:

[0020] (1) The pretreated ethylene tar and medium-temperature coal tar pitch are blended and oxidized;

[0021] (2) Add the pretreated soap residue to the mixture obtained in step (1) and perform condensation treatment;

[0022] (3) The product obtained in step (2) is subjected to ultrasonic treatment to obtain the bonding asphalt.

[0023] In step (1), the pretreatment process of the pretreated ethylene tar is distillation, wherein the pretreated ethylene tar is the fraction of ethylene tar with a temperature greater than 320°C after distillation.

[0024] In step (1), the pretreated ethylene tar and medium-temperature coal tar pitch are blended at 170℃~220℃ for 3~5h. The blending process is carried out under stirring at a speed of 400~600r / min.

[0025] In step (1), after blending, oxidation treatment is carried out in the reactor. The oxidation treatment temperature is 240℃~300℃, and the gas flow rate is 0.05~0.12m³ / h. 3 / (kg·h), oxidation time is 30-60 min, the oxidizing gas is oxygen-enriched air with an oxygen volume content of 60%-75%, and the stirring speed of the oxidation process is 200-400 r / min.

[0026] In step (2), the pretreatment process of the pretreated soap residue is distillation, wherein the pretreated soap residue is the fraction with a temperature greater than 380°C obtained after distillation of the soap residue.

[0027] In step (2), the condensation temperature of the condensation treatment is 330℃~360℃, and the inert gas flow rate is 0.10~0.25m³. 3 The condensation time is 120–200 min, and the inert gas is preferably N2. The stirring speed during the condensation process is 200–400 r / min. The condensation treatment adopts programmed temperature rise, with a heating rate of 0.5–2 °C / min.

[0028] In step (3), the ultrasonic treatment temperature is 200-240℃, the ultrasonic frequency is 40-60kHz, and the ultrasonic treatment time is 30-50min.

[0029] Compared with the prior art, the present invention has the following characteristics:

[0030] (1) This invention introduces pretreated ethylene tar as a co-carbonizing agent to supplement the structure and composition of medium-temperature coal tar pitch, which can effectively improve the coking value of the material. Moreover, the aromatic content in ethylene tar is lower than that in medium-temperature coal tar pitch, which can reduce the release of toxic and harmful substances. This results in an increased degree of condensation, increased aromaticity, and increased content of polycyclic aromatic hydrocarbons, methyl, methylene and aromatic side chains in the final bonded pitch material. The material has better thermal reactivity, lower weight loss, and reduced temperature sensitivity.

[0031] (2) The soap residue used in this invention comes from biomass raw materials and contains different kinds of small molecule active substances. It can promote the polymerization between CC through catalysis without increasing quinoline insoluble matter, thereby increasing the coking value and toluene insoluble matter content of asphalt, and meeting the requirements of bonding asphalt for low softening point, high coking value, and high toluene insoluble matter. The soap residue raw materials used are widely available and inexpensive, which has a certain cost advantage. Furthermore, converting soap residue into carbon materials avoids the environmental pollution caused by direct combustion and meets the requirements of low carbon and environmental protection.

[0032] (3) The present invention performs ultrasonic treatment on the product after condensation treatment. By adjusting the parameters such as ultrasonic frequency, treatment time and treatment temperature, the composition and structure of the product are adjusted and optimized, effectively reducing the viscosity of the material, while having little impact on indicators such as toluene insoluble matter and coking value, so that the material can simultaneously meet the mutual constraints of low softening point and high coking value.

[0033] (4) This invention uses coal-based, petroleum-based and bio-based raw materials to prepare bonding bitumen in a synergistic manner. Compared with traditional single coal-based raw materials, the resulting bonding bitumen can meet the requirements for grade II products in YB / T5194-2015, and has less harm to the environment and human body, and has higher economic value and environmental protection effect. Detailed Implementation

[0034] The technical solution of the present invention is further described below through embodiments, but these embodiments cannot limit the scope of protection of the present invention, and the wt% involved refers to the mass fraction.

[0035] This invention uses a Bruker Avance II 400 nuclear magnetic resonance spectrometer (Germany) to analyze the H and C content at different locations. Specifically, H... ar H represents hydrogen directly bonded to an aromatic carbon. α H represents the hydrogen atom bonded to the α-carbon of the aromatic ring. β H represents the hydrogen on the β-carbon of the aromatic ring and the hydrogen on the CH2 or CH groups attached to the β-carbon. γ This represents the hydrogen on the γ-carbon of the aromatic ring and the hydrogen on the CH3 group attached to the γ-carbon. 1H-NMR can directly provide information on the distribution of hydrogen or carbon atoms at different positions by measuring differences in chemical shift values.

[0036] Example 1

[0037] (1) Mix 100 parts of medium-temperature coal tar pitch with 10 parts of pretreated ethylene tar (fraction above 320℃) and blend at 180℃. The stirring speed during blending is 600 r / min, and the stirring time is 4 h. After blending, perform oxidation treatment in a reactor at 260℃ and an oxidation gas flow rate of 0.05 m³ / min. 3 / (kg . The oxidation process was carried out over a period of 35 minutes (h), with oxygen-enriched air containing 65% oxygen by volume. The stirring speed was maintained at 300 r / min throughout the oxidation process.

[0038] (2) Add 6 parts of pretreated soap residue (fraction above 380℃) to the oxidized mixture obtained in (1), and heat to 340℃ at a programmed heating rate of 2℃ / min, then perform condensation treatment. During the condensation process, nitrogen gas is introduced at a flow rate of 0.15m³. 3 / (kg.h), the condensation time is 120min, and the stirring speed during the heating and condensation process is 200r / min.

[0039] (3) The product obtained in (2) is subjected to ultrasonic treatment at a temperature of 230℃, an ultrasonic frequency of 55kHz, and an ultrasonic treatment time of 40min. After ultrasonic treatment, the bonded asphalt A1 is obtained.

[0040] Example 2

[0041] (1) Mix 100 parts of medium-temperature coal tar pitch with 12 parts of pretreated ethylene tar (fraction with a temperature greater than 320℃), and blend at 190℃. The stirring speed during blending is 600 r / min, and the stirring time is 3.5 h. After blending, perform oxidation treatment in a reactor at a temperature of 270℃ and a gas flow rate of 0.05 m³ / min. 3 / (kg . The oxidation process was carried out over a period of 40 minutes, with oxygen-enriched air containing 70% oxygen by volume. The stirring speed was maintained at 300 r / min throughout the oxidation process.

[0042] (2) Add 6 parts of pretreated soap residue (fraction above 380℃) to the oxidized mixture obtained in (1), and heat to 350℃ at a programmed heating rate of 2℃ / min, then perform condensation treatment. During the condensation process, nitrogen gas is introduced at a flow rate of 0.15m³. 3 / (kg.h), the condensation time is 120min, and the stirring speed during the heating and condensation process is 200r / min.

[0043] (3) The product obtained in (2) is subjected to ultrasonic treatment at a temperature of 220℃, an ultrasonic frequency of 60kHz, and an ultrasonic treatment time of 40min. After ultrasonic treatment, the bonded asphalt A2 is obtained.

[0044] Example 3

[0045] (1) Mix 100 parts of medium-temperature coal tar pitch with 12 parts of pretreated ethylene tar (fraction with a temperature greater than 320℃), and blend at 180℃. The stirring speed during blending is 600 r / min, and the stirring time is 4 h. After blending, perform oxidation treatment in a reactor at a temperature of 260℃ and an oxidation gas flow rate of 0.05 m³ / min. 3 / (kg . The oxidation process was carried out over a period of 35 minutes (h), with oxygen-enriched air containing 65% oxygen by volume. The stirring speed was maintained at 300 r / min throughout the oxidation process.

[0046] (2) Add 8 parts of pretreated soap residue (fraction above 380℃) to the oxidized mixture obtained in (1), and heat to 340℃ at a programmed heating rate of 2℃ / min, then perform condensation treatment. During the condensation process, nitrogen gas is introduced at a flow rate of 0.15m³. 3 / (kg.h), the condensation time is 120min, and the stirring speed during the heating and condensation process is 200r / min.

[0047] (3) The product obtained in (2) is subjected to ultrasonic treatment at a temperature of 230℃, an ultrasonic frequency of 50kHz, and an ultrasonic treatment time of 50min. After ultrasonic treatment, the bonded asphalt A3 is obtained.

[0048] Example 4

[0049] (1) Mix 100 parts of medium-temperature coal tar pitch with 10 parts of pretreated ethylene tar (fraction above 320℃) and blend at 180℃. The stirring speed during blending is 600 r / min, and the stirring time is 4 h. After blending, perform oxidation treatment in a reactor at 250℃ and an oxidation gas flow rate of 0.05 m³ / min. 3 / (kg . The oxidation process was carried out over a period of 35 minutes, with oxygen-enriched air containing 70% oxygen by volume. The stirring speed was maintained at 300 r / min throughout the oxidation process.

[0050] (2) Add 8 parts of pretreated soap residue (fraction above 380℃) to the oxidized mixture obtained in (1), and heat to 350℃ at a programmed heating rate of 1.5℃ / min, then perform condensation treatment. During the condensation process, nitrogen gas is introduced at a flow rate of 0.15m³. 3 / (kg.h), the condensation time is 120min, and the stirring speed during the heating and condensation process is 200r / min.

[0051] (3) The product obtained in (2) is subjected to ultrasonic treatment at a temperature of 230℃, an ultrasonic frequency of 50kHz, and an ultrasonic treatment time of 45min. After ultrasonic treatment, the bonded asphalt A4 is obtained.

[0052] Comparative Example 1

[0053] Same as Example 1, except that the ethylene tar used in the preparation process is not pretreated by distillation to obtain bonding pitch B1.

[0054] Comparative Example 2

[0055] Same as Example 1, except that the soap residue used in the preparation process is not pretreated by distillation to obtain bonding bitumen B2.

[0056] Comparative Example 3

[0057] Same as Example 1, except that the pretreated soap residue used in the preparation process is a fraction with a temperature greater than 300°C, to obtain binding asphalt B3.

[0058] Comparative Example 4

[0059] Same as Example 1, except that the amount of pretreated soap residue added during the preparation process is 2 parts, resulting in bonding bitumen B4.

[0060] Comparative Example 5

[0061] Same as Example 1, except that no condensation treatment is performed during the preparation process to obtain bonding bitumen B5.

[0062] Comparative Example 6

[0063] Same as Example 1, except that ultrasonic treatment is not performed during the preparation process to obtain bonding bitumen B6.

[0064] Test case

[0065] The main properties of the raw materials used in the examples and comparative examples were analyzed and tested, as shown in Tables 1 to 3. The main properties of the bonding asphalt prepared in the examples and comparative examples were analyzed, and the analysis methods were in accordance with the requirements of YB / T5194-2015. The results are shown in Table 4.

[0066] Table 1. Some properties of the medium-temperature coal tar pitch used in the examples and comparative examples.

[0067] Softening point / °C 80.6 Toluene insolubles TI / wt% 5.74 Quinoline insoluble matter QI / wt% 0.85 Coking value CV / wt% 6.9 C / wt% 83.66 H / wt% 6.64 O / wt% 6.52 N / wt% 2.51 S / wt% 0.12 β resin / wt% 49

[0068] Table 2. Properties of some ethylene tar used in the examples and comparative examples.

[0069] Carbon residue value / wt% 14.28 Saturated fraction / wt% 1.07 Aromatic components / wt% 65.14 Gel / wt% 32.58 Asphalt / wt% 1.21 Initial boiling point / °C ＜175℃ <![CDATA[H ar / wt%]]> 46.52 <![CDATA[H α / wt%]]> 33.41 <![CDATA[H β / wt%]]> 15.03 <![CDATA[H γ / wt%]]> 5.04 C / H (molar ratio) 12.37 S / N (molar ratio) 16.44

[0070] Table 3. Properties of soap residue used in the examples and comparative examples.

[0071] Penetration (25℃) / 0.1mm 198 Softening point / °C 40.3 Flash point / °C 247 Solubility (trichloroethylene) / wt% 99.95 Initial boiling point / °C ＜310℃ Dynamic viscosity at 60℃ / Pa·s 71.27 Fatty acids / wt% 42.4 Unsaponifiable matter / wt% 12.6 Free carbon / wt% 0.5 Asphalt and resins / wt% 46.2

[0072] Table 4 Properties of the bonding asphalt prepared in the examples and comparative examples

[0073]

[0074]

[0075] The scope of protection of this invention is not limited to the above embodiments, but is defined by the claims. Those skilled in the art can make appropriate modifications to these embodiments without departing from the technical concept and spirit of this invention, and these modified embodiments are also included within the scope of protection of this invention.

Claims

1. A binding bitumen, characterized in that the binding bitumen, by weight, comprises the following components: Medium-temperature coal tar pitch: 100 parts; Pre-treated ethylene tar: 5-20 parts, preferably 5-15 parts; Pre-treated soap residue: 3-15 parts, preferably 5-10 parts.

2. The binding bitumen according to claim 1, characterized in that, The properties of the medium-temperature coal tar pitch include: C 82.13wt%–84.51wt%, H 6.26wt%–7.36wt%, O 6.45wt%–7.02wt%, N 2.49wt%–2.85wt%, S 0.06wt%–0.15wt%; softening point 78–84℃; toluene-insoluble content (TI) 5.61–6.34wt%; quinoline-insoluble content (QI) 0.58–1.03wt%; coking value (CV) not less than 6wt%, preferably 6–15wt%; and β-resin not less than 5.45wt%.

3. The binding bitumen according to claim 1, characterized in that, The pretreated ethylene tar is the fraction obtained from ethylene tar after distillation at a temperature greater than 320°C. The ethylene tar has the following properties: saturated content of 0.1 wt% to 2.6 wt%, aromatic content of 54 wt% to 69 wt%, resin content of 25 wt% to 34 wt%, asphaltenes content of 0.5 wt% to 4.1 wt%, carbon residue of 11 wt% to 15 wt%, C / H molar ratio of 12 to 14, and S / N molar ratio of 14 to 20; H ar 45wt%–48wt%, H α 31wt%–35wt%, H β accounting for 14wt% to 16wt%, H γ It accounts for 4 wt% to 7 wt%.

4. The binding bitumen according to claim 1, characterized in that, The soap residue is the residue remaining after the extraction of fatty acids from soap residue, preferably the residue remaining after the extraction of fatty acids from cottonseed oil soap residue. And / or, the properties of the soap residue include: a penetration of 190–205 1 / 10 mm at 25°C, a softening point of 39–44°C, a flash point of not less than 245°C, a solubility (with trichloroethylene as solvent) of not less than 99.9 wt%, a total content of asphaltenes and gums of not less than 45 wt%, a dynamic viscosity of 69.64–74.59 Pa·s at 60°C, a fatty acid content of 40–50 wt%, an unsaponifiable matter content of 10–15 wt%, and a free carbon content of 0.3–0.8 wt%.

5. The binding bitumen according to claim 1 or 4, characterized in that, The pretreated soap residue is the fraction obtained by distilling soap residue and cutting it at a temperature greater than 380°C.

6. A method for preparing the binding bitumen according to any one of claims 1-5, comprising: (1) The pretreated ethylene tar and medium-temperature coal tar pitch are blended and oxidized; (2) Add the pretreated soap residue to the mixture obtained in step (1) and perform condensation treatment; (3) The product obtained in step (2) is subjected to ultrasonic treatment to obtain the bonding asphalt.

7. The preparation method according to claim 6, characterized in that, In step (1), the pretreatment process of the pretreated ethylene tar is distillation, wherein the pretreated ethylene tar is the fraction of ethylene tar with a temperature greater than 320°C after distillation.

8. The preparation method according to claim 6, characterized in that, In step (1), the pretreated ethylene tar and medium-temperature coal tar pitch are blended at 170℃~220℃ for 3~5h. The blending process is carried out under stirring at a speed of 400~600r / min.

9. The preparation method according to claim 6, characterized in that, In step (1), the oxidation treatment temperature is adjusted to 240℃~300℃ and the gas flow rate is 0.05~0.12m³ / h. 3 / (kg·h), oxidation time is 30-60 min, the oxidizing gas is oxygen-enriched air with an oxygen volume content of 60%-75%, and the stirring speed of the oxidation process is 200-400 r / min.

10. The preparation method according to claim 6, characterized in that, In step (2), the pretreatment process of the pretreated soap residue is distillation, wherein the pretreated soap residue is the fraction with a temperature greater than 380°C obtained after distillation of the soap residue.

11. The preparation method according to claim 6, characterized in that, In step (2), the condensation temperature of the condensation treatment is 330℃~360℃, and the inert gas flow rate is 0.10~0.25m³. 3 / (kg.h), the condensation time is 120-200 min, and the inert gas is preferably N2; the stirring speed during the condensation process is 200-400 r / min; the condensation treatment adopts programmed heating with a heating rate of 0.5-2℃ / min.

12. The preparation method according to claim 6, characterized in that, In step (3), the ultrasonic treatment temperature is 200-240℃, the ultrasonic frequency is 40-60kHz, and the ultrasonic treatment time is 30-50min.

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