Petroleum-based binder for prebaked anodes and method for its production

Abstract

The application provides a petroleum-based binder for prebaked anodes and a preparation method thereof, and relates to the technical field of prebaked anode production. The preparation of the petroleum-based binder comprises the following steps: mixing residual oil and an activating agent, then performing a first polymerization reaction by heating, cooling after the reaction, and obtaining a modified binder; mixing the obtained modified binder with a vacuum distillation fraction of catalytic slurry oil, then melting by heating, sealing, heating, performing a second polymerization reaction, cooling after the reaction, and obtaining the petroleum-based binder for prebaked anodes. The two-stage thermal polymerization method is adopted, the first stage is a medium-low temperature thermal polymerization method, the small molecules in the residual oil are modified by the medium-low temperature thermal polymerization, and the carbon residue rate of the pitch is improved; the second stage of thermal polymerization mainly makes the unreacted groups of the modified binder in the first stage continue to perform a thermal polymerization reaction with the treated catalytic slurry oil at high temperature, and the modified binder coal pitch for prebaked anodes with high carbon residue and low viscosity is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of prebaked anode production, and particularly relates to a method for preparing a binder for prebaked anodes by polymerization of residual oil and catalytic slurry oil and a petroleum-based binder prepared by the method. BACKGROUND

[0002] The production process of prebaked anodes is to use petroleum coke, a byproduct of oil refineries, as an aggregate, accounting for more than 80% of the total mass of prebaked anodes, and to use modified pitch as a binder to manufacture prebaked anodes. The cost of petroleum coke and the binder accounts for about 75% of the production cost of prebaked anodes. The production uses petroleum coke and modified pitch as raw materials, forms carbon blocks after being bonded by modified pitch, and then performs baking treatment to obtain prebaked anodes. The modified pitch used in the existing prebaked anode production is basically modified coal pitch, and its quality directly affects the performance of prebaked anodes (such as bulk density, compressive strength, electrical conductivity, and thermal conductivity). These performances are closely related to the bonding performance and coking value of modified coal pitch.

[0003] At present, domestic electrolytic aluminum anode manufacturing enterprises generally use medium-temperature coal pitch as a binder. However, coal pitch has a high impurity content, and its properties are unstable due to the influence of the production site. The pretreatment is difficult in the early stage, and with the restriction of the production capacity of the high-energy consumption and high-emission steel industry in China, the production of coal pitch has decreased, and the price has risen. At present, the price of coal pitch used in the prebaked anode industry is 4000-6000 yuan / ton. Compared with coal pitch, petroleum-based raw materials have low impurity content, wide raw material sources, stable properties, and simple pretreatment process. Foreign countries have carried out application research on using petroleum pitch or mixing a certain proportion of high-softening-point petroleum pitch in medium-temperature coal pitch as a binder. Therefore, developing and preparing petroleum coke binders for prebaked anodes from petroleum-based raw materials can reduce the production cost of prebaked anodes and prolong the service life of prebaked anodes.

[0004] Generally in the production process of carbon anode, the content of β resin, quinoline insoluble QI and softening point are used as the indexes to characterize the superiority of pitch. The β resin is the main binder component of coal tar pitch. The greater the coking value of the coke generated by the β resin, the better the coking performance, the solid pore wall and the fibrous structure, and the higher the strength and the smaller the resistance of the product. Therefore, the β component of the binder pitch is particularly important. Generally, the β component of the coal tar pitch for aluminum carbon anode is more than 18%, and the corresponding coking value requirement is greater than 55%. Increasing QI can enhance the structure of pitch coke, but too high QI will reduce the flowability of pitch; too low QI content will cause paste segregation and stratification. The QI content of the coal tar pitch for aluminum carbon anode is generally required to be 9% to 12%. Due to the complexity and variability of the composition and properties of coal tar pitch, it is difficult to strictly distinguish the determining influence of a single pitch component or property on the quality of carbon anode, so the influence of the comprehensive performance of pitch on the prebaked anode needs to be considered, and how to improve the comprehensive performance of the binder pitch has become a problem to be solved for the prebaked anode manufacturers. SUMMARY

[0005] One of the purposes of the present application is to provide a preparation method of a petroleum-based binder for prebaked anode.

[0006] The second purpose of the present application is to provide a petroleum-based binder prepared by the above method.

[0007] In order to achieve the above purposes of the present application, the following technical solutions are adopted:

[0008] In the first aspect, the present application provides a preparation method of a petroleum-based binder for prebaked anode, comprising the following steps:

[0009] Mixing the residual oil with an activator, then heating for the first polymerization reaction, and introducing air into the reaction material during the heating process, and then cooling after the reaction to obtain a modified binder;

[0010] Performing solid removal treatment on the catalytic slurry, and then performing vacuum distillation to cut the fraction ≥ 350-400℃ above;

[0011] Mixing the obtained modified binder with the fraction after vacuum distillation of the catalytic slurry, and then heating and melting, sealing and heating for the second polymerization reaction, and then cooling after the reaction to obtain a petroleum-based binder for prebaked anode.

[0012] The following will be described in detail:

[0013] Preparation of modified binder:

[0014] The residual oil refers to the residual oil extracted from the bottom of the vacuum tower after vacuum distillation of crude oil as raw material.

[0015] In some embodiments, the residue oil has the following properties: density (20℃) of 0.9916-1.0215 g / cm 3 , carbon residue content of 15.01-16.21 wt%, and softening point of 44.8-52.8℃.

[0016] In some embodiments, the activator is one or more selected from p-methylstyrene, p-methylbenzaldehyde or mesitylene, and the amount of the activator is 1-2.5 wt% of the amount of the residue oil added.

[0017] In some embodiments, the residue oil is preheated before mixing with the activator, the preheating temperature is 60-80℃, and the preheating time is 30-40 min.

[0018] In some embodiments, the first polymerization reaction at elevated temperature comprises: first freely heating to 100℃, then heating to 150-200℃ at a rate of 5-10℃ / min, and reacting at this temperature for 3-5 h.

[0019] In some embodiments, the first polymerization reaction is carried out in a low-temperature stirring reactor under normal pressure.

[0020] In this step, the residue oil is crosslinked by adding the activator. Since the activator has a low boiling point, in order to prevent the activator from volatilizing at high temperature and causing the activity of the activator to decrease, a low-temperature slow reaction mode is adopted to make the chemical activator promote the molecular crosslinking of the branched alkane components in the residue oil, which prevents both the volatilization and deactivation of the activator and the excessive polymerization of small molecules.

[0021] In some embodiments, air is introduced into the reaction material in the stirring reactor, the flow rate of the introduced air is 3-5 L / min, and the time for introducing the air is 3-5 h. By introducing oxygen molecules, oxidation reaction is continued to promote the crosslinking of the components in the residue oil.

[0022] Preparation of the fraction after vacuum distillation of the catalytic slurry oil:

[0023] The catalytic slurry oil refers to the residual oil produced by the catalytic cracking device of a refinery.

[0024] In some embodiments, the desolidification agent used for desolidification treatment is a combination of demulsifiers, flocculants and the like, and commercially available products can be used, which have a density (20℃) ≥ 0.82 g / cm 3 , viscosity (40℃) of 100-150 mm 2 / s, and a freezing point ≤-25℃.

[0025] In some embodiments, the amount of the desolidification agent used for desolidification treatment is 300-500 mg / kg, and the standing time for desolidification treatment is 36-48 h.

[0026] The desolidation oil slurry ash content is <0.1%, preferably <0.03%.

[0027] In some embodiments, the process parameters of the vacuum distillation include: a vacuum distillation temperature of 350-550℃, and a pressure value of 0.1-0.5Mpa.

[0028] The cut fraction is preferably a fraction ≥400℃.

[0029] The catalytic oil slurry is rich in a large amount of condensed ring aromatic hydrocarbons, which are beneficial to improving the softening point and viscosity of the reaction product in the subsequent reaction and reducing the production of quinoline insolubles, but these condensed ring aromatic hydrocarbons are enriched in the fraction ≥350℃, therefore, the catalytic oil slurry needs to be vacuum distilled to remove light components, and the binder has certain requirements for the ash content, and if the ash content is too high, defects may occur during the bonding with the prebaked anode, therefore, the catalytic oil slurry also needs to be desolidated to reduce the ash content to a suitable range.

[0030] Second polymerization reaction:

[0031] In some embodiments, the mixing mass ratio of the modified binder to the fraction after the vacuum distillation of the catalytic oil slurry is 3:1-2:1.

[0032] In some embodiments, the melting is slowly heated at a rate of 5-10℃ / min.

[0033] In some embodiments, after sealing, the temperature is raised to 300-350℃, the second polymerization reaction time is 4-6h, and the second polymerization reaction pressure is 0.2-0.4MPa.

[0034] In some embodiments, the second polymerization reaction is carried out in a micro-pressure high-temperature stirring reactor.

[0035] After the reaction is completed, the reaction product is naturally cooled to obtain a high-residual-carbon and low-viscosity binder for prebaked anodes.

[0036] In a second aspect, the application provides a petroleum-based binder for prebaked anodes, which is prepared by the above preparation method.

[0037] The obtained binder has a bitumen softening point of 105-110℃, a quinoline insoluble content of 7-11%, and an ash content of <0.05%, which meets the requirements of the binder for prebaked anodes.

[0038] Technical effects:

[0039] (1) In order to ensure the comprehensive performance of the modified binder, firstly, a two-stage thermal polymerization method is adopted, the first stage is a low-temperature thermal polymerization method, which can prevent the volatilization of the chemical active agent caused by high temperature and effectively ensure the activity of the chemical active agent. The chemical active agent is added to the residual oil first, and the small molecules in the residual oil are modified by low-temperature thermal polymerization, which can improve the controllability of the thermal polymerization reaction, make the asphalt molecules orderly polymerize, and then introduce air into the reaction process to provide oxygen source for the reaction. In this way, the side chain alkanes in the residual oil can be broken and further thermal polycondensation can be carried out. By controlling the time and flow of air introduced, the residual oil can be prevented from excessive crosslinking reaction, and a suitable modified asphalt can be obtained. At the same time, the high activity of the residual oil molecules and the large degree of condensation are beneficial to improve the carbon residue rate of the asphalt. In addition, the introduction of methyl substituent structure can improve the fluidity of the asphalt.

[0040] (2) By carrying out solid removal and vacuum distillation treatment on the catalytic oil slurry, a reaction component rich in polycyclic aromatic hydrocarbons is obtained. In the second stage of polymerization, the polycyclic aromatic hydrocarbons participate in the reaction, which can improve the softening point and viscosity of the product, and at the same time, the QI insoluble of the product will not be greatly increased.

[0041] (3) The process of the present application is simple, controllable, convenient to operate, and requires less reaction equipment. The comprehensive performance of the obtained binder is stable. At the same time, the residual oil and catalytic oil slurry are used as raw materials, which has the advantages of low cost and basically consistent product properties compared with modified coal tar pitch.

[0042] The present application has been described in detail in the foregoing, but the above-mentioned embodiments are only illustrative in nature and are not intended to limit the present application. In addition, the present application is not limited by any theory described in the foregoing prior art or the following examples or the following examples. DETAILED DESCRIPTION

[0043] The present application will be further described in conjunction with the following examples. It should be noted that the following examples are provided only for illustrative purposes and do not constitute a limitation on the scope of the present application.

[0044] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, methods in the art.

[0045] The catalytic oil slurry is obtained from the residual oil produced by the catalytic cracking device of the oil refinery.

[0046] Test method: softening point, quinoline insoluble, ash content is determined according to GB / T8730-98 method.

[0047] Example 1

[0048] (1) A certain amount of residual oil was weighed, and the basic properties of the residual oil were as follows: a density (20°C) of 0.9916 cm 3 , a carbon residue content of 15.01 wt%, and a softening point of 52.8°C. The residual oil was then preheated at a preheating temperature of 60°C, and after preheating for 30 min, it was transferred into a polymerization kettle. p-Methylstyrene was then added and stirred and mixed. After uniform mixing, the temperature was raised to 100°C, and after 100°C, the temperature was raised to 150°C at a rate of 5°C / min. The reaction was carried out at this temperature for 3 h, and air was introduced into the system during the reaction at a flow rate of 3 L / min for 3 h. After the reaction was completed, the system was immediately cooled to room temperature, and a crosslinked modified binder was obtained.

[0049] (2) The FCC slurry was subjected to desolidification treatment by adding a desolidifying agent at an amount of 300 mg / kg, and the slurry was allowed to stand for 36 h. After desolidification, the ash content of the slurry was <0.03%. The desolidified slurry was then subjected to vacuum distillation treatment, and a fraction with a boiling point of ≥350°C was cut.

[0050] (3) The modified binder obtained in step (1) was mixed with the fraction oil obtained in step (2) at a ratio of 2:1, and the mixture was slowly heated and melted at a rate of 5 min. After sealing, the temperature was slowly raised to 300°C, and a constant temperature reaction was carried out for 4 h. During the reaction, the system pressure was maintained within the range of 0.2 MPa. After the reaction was completed, the reaction product was naturally cooled, and a high-residual-carbon and low-viscosity binder for prebaked anodes was obtained.

[0051] Example 2

[0052] (1) A certain amount of residual oil was weighed, and the basic properties of the residual oil were as follows: a density (20°C) of 1.0215 cm 3 , a carbon residue content of 16.21 wt%, and a softening point of 52.8°C. The residual oil was then preheated at a preheating temperature of 80°C, and after preheating for 30 min, it was transferred into a polymerization kettle. p-Methylstyrene was then added and stirred and mixed. After uniform mixing, the temperature was raised to 100°C, and after 100°C, the temperature was raised to 200°C at a rate of 10°C / min. The reaction was carried out at this temperature for 5 h, and air was introduced into the system during the reaction at a flow rate of 5 L / min for 5 h. After the reaction was completed, the system was immediately cooled to room temperature, and a crosslinked modified binder was obtained.

[0053] (2) The FCC slurry was subjected to desolidification treatment by adding a desolidifying agent at an amount of 500 mg / kg, and the slurry was allowed to stand for 48 h. After desolidification, the ash content of the slurry was <0.03%. The desolidified slurry was then subjected to vacuum distillation treatment, and a fraction with a boiling point of ≥400°C was cut.

[0054] (3) The modified adhesive obtained in step (1) is mixed with the fraction oil obtained in step (2) at a ratio of 3:1, and after being mixed uniformly, it is slowly heated and melted at a rate of 10 min, and after being sealed, it is slowly heated to 350°C, and then it is kept at a constant temperature for 6 h. During the reaction, the pressure of the system is kept within the range of 0.4 MPa. After the reaction is completed, the reaction product is naturally cooled to obtain a high-residual-carbon and low-viscosity adhesive for a prebaked anode.

[0055] Example 3

[0056] (1) A certain amount of residual oil is weighed, and the basic properties of the residual oil are as follows: the density (20°C) is 0.9975 cm 3 , the carbon residue content is 15.921 wt%, and the softening point is 50.8°C. The residual oil is preheated to 80°C, and after being preheated for 30 min, it is transferred into a polymerization kettle. p-Methylstyrene is then added and mixed. After being mixed uniformly, the temperature is increased to 100°C, and then the temperature is increased to 150°C at a rate of 5°C / min. The reaction is carried out at this temperature for 4 h. During the reaction, air is introduced at a flow rate of 3 L / min for 4 h. After the reaction is completed, the reaction product is immediately cooled to room temperature to obtain a crosslinked modified binder.

[0057] (2) The catalytic slurry oil is treated by adding a desolidification agent. The amount of the desolidification agent added is 400 mg / kg, and the oil slurry is allowed to stand for 48 h. After desolidification, the ash content of the oil slurry is <0.03%. The desolidified oil slurry is further subjected to vacuum distillation treatment to cut out a fraction with a boiling point of ≥400°C.

[0058] (3) The modified adhesive obtained in step (1) is mixed with the fraction oil obtained in step (2) at a ratio of 3:1, and after being mixed uniformly, it is slowly heated and melted at a rate of 5 min, and after being sealed, it is slowly heated to 300°C, and then it is kept at a constant temperature for 6 h. During the reaction, the pressure of the system is kept within the range of 0.3 MPa. After the reaction is completed, the reaction product is naturally cooled to obtain a high-residual-carbon and low-viscosity adhesive for a prebaked anode.

[0059] Example 4

[0060] (1) A certain amount of residual oil is weighed, and the basic properties of the residual oil are as follows: the density (20°C) is 0.9916 cm 3, the softening point is 44.8℃; the residual oil is preheated, the preheating temperature is 80℃, after preheating for 30min, it is transferred into the polymerization kettle, then mesitylene is added for stirring and mixing, after mixing evenly, the temperature is increased, to 100℃, then to 150℃ at a rate of 5℃ / min, and reaction is carried out at this temperature for 5h, air is introduced during the reaction, the air flow is 4L / min, the air introduction time is 5h, after the reaction is completed, it is cooled to room temperature immediately, to obtain the crosslinked modified binder.

[0061] (2) The catalytic oil slurry is treated by adding a desolidarizing agent, the desolidarizing agent is added at a dosage of 500mg / kg, the oil slurry is placed for 36h, the ash content of the oil slurry after desolidarization is <0.03%, the oil slurry after desolidarization is further treated by vacuum distillation, and the fraction above 350℃ is cut.

[0062] (3) The modified binder obtained in step (1) is mixed with the fraction oil obtained in step (2) at a ratio of 2:1, after mixing evenly, it is slowly heated and melted at a rate of 100min, after sealing, it is slowly heated to 350℃, then constant temperature reaction is carried out for 5h, during the reaction, the system pressure is maintained within 0.2MPa, after the reaction is completed, the reaction product is naturally cooled, to obtain the binder for prebaked anode with high residual carbon and low viscosity.

[0063] Comparative Example 1

[0064] A certain amount of residual oil is weighed, the basic properties of the residual oil are as follows: the density (20℃) is 0.9916cm 3 , the softening point is 44.8℃; the residual oil is preheated, the preheating temperature is 80℃, after preheating for 30min, it is transferred into the polymerization kettle, then mesitylene is added for stirring and mixing, after mixing evenly, the temperature is increased, to 100℃, then to 320℃ at a rate of 5℃ / min, and reaction is carried out at this temperature for 4h, after the reaction is completed, it is cooled to room temperature immediately, to obtain the crosslinked modified binder.

[0065] Comparative Example 2

[0066] A certain amount of residual oil is weighed, the basic properties of the residual oil are as follows: the density (20℃) is 0.9916cm 3, the carbon residue content is 15.01wt%, and the softening point is 44.8℃; the residual oil is preheated, the preheating temperature is 80℃, after preheating for 30min, it is transferred into the polymerization kettle, and then the uniform tetramethylbenzene is added to stir and mix; after mixing, the temperature is increased to 100℃, then the temperature is increased to 150℃ at a rate of 5℃ / min, and the reaction is carried out at this temperature for 5h; after the reaction is completed, the cut catalytic oil slurry is mixed at a ratio of 2:1, and then slowly heated and melted at a rate of 100min; after sealing, the temperature is slowly increased to 350℃, and then the reaction is carried out at this temperature for 5h; during the reaction, the system pressure is maintained within the range of 0.2MPa; after the reaction is completed, the reaction product is naturally cooled.

[0067] Table 1: Performance analysis results of sample of example and comparative example

[0068]

[0069] As shown in Table 1, the emulsification point, quinoline insoluble and ash of the binder for prebaked anode obtained by the present application are similar to the indexes of modified coal tar pitch special for prebaked anode, which indicates that the product obtained by the process using residual oil and catalytic oil slurry as raw materials meets the demand of the binder for prebaked anode; at the same time, the performance of the binder obtained by one-step method using residual oil as raw material is poor, the softening point and quinoline insoluble do not meet the index requirements; the softening point and quinoline insoluble indexes of the product obtained by the two-step method without oxidation and polycondensation of residual oil and catalytic oil slurry are not as good as those of the product of the example.

[0070] The above examples are only used to illustrate the technical solutions of the present application, but not limit the present application. Although the present application is described in detail with reference to the above examples, those skilled in the art should understand that the technical solutions recorded in the above examples can be modified, or some or all of the technical features can be replaced by equivalents without departing from the spirit and essence of the present application defined in the claims of the present application; and these modifications or replacements are still within the scope defined by the claims of the present application.

Claims

1. A process for the preparation of petroleum-based binders for prebaked anodes, characterized in that, The method comprises the following steps: mixing the residual oil with an activating agent, then heating to carry out a first polymerization reaction, during the heating, air is introduced into the reaction material, after the reaction, cooling to obtain a modified binder; the heating to carry out the first polymerization reaction comprises: first heating to 100℃, then heating at a rate of 5-10℃ / min to 150-200℃, and reacting at this temperature for 3-5h; carrying out a desolidification treatment on the FCC slurry, then carrying out vacuum distillation to cut a fraction above ≥350-400℃; mixing the modified binder obtained with the fraction after the vacuum distillation of the FCC slurry, then slowly heating to melt at a rate of 5-10℃ / min, after sealing, heating to 300-350℃ to carry out a second polymerization reaction, the time of the second polymerization reaction is 4-6h, the pressure of the second polymerization reaction is 0.2-0.4MPa, after the reaction, cooling to obtain a petroleum-based binder for prebaked anode.

2. The method of claim 1, wherein, The residue has the following properties: density at 20°C of 0.9916-1.0215 g / cm 3 , carbon residue content of 15.01-16.21 wt%, softening point of 44.8-52.8°C.

3. The method of claim 1, wherein, The activating agent is one or several selected from p-methylstyrene, p-methylbenzaldehyde or mesitylene, and the amount added is 1-2.5wt% of the amount of the residual oil.

4. The method of claim 1, wherein, The flow rate of the air introduced is 3-5L / min, and the time of the air introduced is 3-5h.

5. The method of claim 1, wherein, The amount of the desolidification agent used for the desolidification treatment is 300-500mg / kg, and the standing time of the desolidification treatment is 36-48h.

6. The method of claim 1, wherein, The mixing mass ratio of the modified binder to the fraction after the vacuum distillation of the FCC slurry is 3:1-2:

1.

7. An oil-based binder for prebaked anodes, characterized in that Prepared by the method of any one of claims 1-6.

8. The petroleum-based binder for prebaked anodes according to claim 7, characterized in that, The petroleum-based binder for prebaked anode has a pitch softening point of 105-110℃, quinoline insolubles of 7-11%, and ash content of <0.05%.

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