Purification method of carbon black raw oil, conductive carbon black and application thereof

Abstract

This invention relates to the field of carbon black preparation, and particularly to a method for purifying carbon black feedstock oil, conductive carbon black, and their applications. The purification method for carbon black feedstock oil includes the following steps: pretreating the carbon black feedstock oil to prepare crude carbon black feedstock oil; and subjecting the crude carbon black feedstock oil to electric field treatment. This invention confines alkali metal ions in the feedstock oil to the bottom of the preheater by applying an external electric field, preventing them from participating in the carbon black formation process, thereby reducing the impact of alkali metal ions on the carbon black structure.

Description

Technical Field

[0001] This invention relates to the field of carbon black preparation, and in particular to a method for purifying carbon black feedstock oil, conductive carbon black, and its applications. Background Technology

[0002] Carbon black is a black powdery substance produced by the incomplete combustion or pyrolysis of hydrocarbons (usually called carbon black feedstock oil) under strictly controlled process conditions. Its main component is elemental carbon, with small amounts of oxygen, hydrogen, and sulfur. To ensure that semi-conductive shielding materials have good processing and physical-mechanical properties, conductive carbon black with good conductivity should be selected. These carbon blacks must possess a special graphitized structure; therefore, carbon blacks with high oil absorption values ​​and large specific surface areas should be chosen. The oil absorption value of carbon black represents the degree of carbon black aggregate structure. Generally speaking, the higher the oil absorption value, the higher the structure of the carbon black, the more developed the branches, and the more conducive it is to the formation of a conductive interconnected network.

[0003] The structure of carbon black refers to the aggregation state and degree of its basic particles, encompassing both primary and secondary structures. Most carbon black varieties have particle sizes within the nanometer range (<100nm), and their surfaces are rich in active groups, inevitably leading to some degree of agglomeration between particles. The carbon black manufacturing process is conducted under consistently high temperatures, causing adjacent particles to be generated simultaneously, melting together to form chains occupying three-dimensional space—this is called the primary structure. In the post-processing stage, structures formed between primary structures due to physical adsorption, van der Waals forces, or electrostatics are called secondary structures. Secondary structures are relatively loose and easily disrupted, and since the structure of carbon black has a crucial impact on its properties, improving the primary structure of carbon black is of great significance. Summary of the Invention

[0004] To address the above problems, this invention provides a method for purifying carbon black feedstock oil, which can prepare high-purity carbon black feedstock oil that can be used to prepare conductive carbon black and improve the primary structure of conductive carbon black.

[0005] This invention is achieved through the following technical solution:

[0006] A method for purifying carbon black feedstock oil includes the following steps:

[0007] The carbon black feedstock oil is pretreated to prepare crude carbon black feedstock oil.

[0008] The crude carbon black feedstock oil is subjected to electric field treatment.

[0009] In some embodiments, the electric field treatment steps include:

[0010] An electric field is applied to the crude carbon black feedstock oil to cause the alkali metal ions in the crude carbon black feedstock oil to move in a specific direction.

[0011] In some embodiments, the alkali metal ions include one or more of potassium ions and sodium ions, and the electric field strength corresponding to 1 ppm of the alkali metal ions is ≥10 V / m.

[0012] In some embodiments, the alkali metal ions are a mixture of potassium and sodium ions, and the electric field strength corresponding to 1 ppm of the alkali metal ions is ≥50V / m.

[0013] In some embodiments, the carbon black feedstock oil includes one or more of coal tar, carbon black oil, anthracene oil, and ethylene tar.

[0014] In some embodiments, the ash content of the coal tar is ≤0.1%.

[0015] In some embodiments, the moisture content of the coal tar is ≤4.0%.

[0016] In some embodiments, the toluene-insoluble content of the coal tar is ≤6.0%.

[0017] In some embodiments, the coal tar has a density of 1.16 g / cm³ at 20°C. 3 ~1.19g / cm 3 .

[0018] In some embodiments, the ash content of the carbon black oil is ≤0.1%.

[0019] In some embodiments, the moisture content of the carbon black oil is ≤0.5%.

[0020] In some embodiments, the carbon black oil has a toluene-insoluble content of ≤6.0%.

[0021] In some embodiments, the carbon black oil has a density of 1.19 g / cm³ at 20°C. 3 ~1.21g / cm 3 .

[0022] In some embodiments, the anthracene oil is derived from the 300°C to 360°C fraction of coal tar.

[0023] In some embodiments, the anthracene oil has an ash content of ≤0.02%.

[0024] In some embodiments, the anthracene oil has a moisture content of ≤0.5%.

[0025] In some embodiments, the toluene-insoluble content of the anthracene oil is ≤0.2%.

[0026] In some embodiments, the anthracene oil has a density of 1.12 g / cm³ at 20°C. 3 ~1.14g / cm 3 .

[0027] In some embodiments, the ash content of the ethylene tar is ≤0.03%.

[0028] In some embodiments, the moisture content of the ethylene tar is ≤0.5%.

[0029] In some embodiments, the toluene-insoluble content of the ethylene tar is ≤0.3%.

[0030] In some embodiments, the ethylene tar has a density of 1.06 g / cm³ at 20°C. 3 ~1.10g / cm 3 .

[0031] In some embodiments, the feedstock oil comprises a mixture of anthracene oil and ethylene tar, wherein the mass ratio of the anthracene oil to the ethylene tar is ≥7:3.

[0032] In some implementations, the preprocessing includes the following steps:

[0033] The raw material oil is heated to 80℃~90℃, and the crude carbon black raw material oil is prepared by sedimentation treatment and solid-liquid separation treatment.

[0034] This invention also provides a method for preparing conductive carbon black, comprising the following steps:

[0035] Provide carbon black feedstock oil, and purify the carbon black feedstock oil according to the above-mentioned purification method to prepare pure feedstock oil;

[0036] The conductive carbon black is prepared by applying an electric field to the pure raw oil for pyrolysis, granulation, desorption, and refining.

[0037] In some embodiments, crude carbon black is prepared by pyrolysis, wherein the pyrolysis conditions include an air-to-natural gas volume ratio of (17-20):1.

[0038] In some embodiments, the conditions for pyrolysis treatment include increasing the combustion temperature of the reactor combustion section to 1600°C to 1800°C.

[0039] In some embodiments, the conditions for the pyrolysis treatment include a feedstock flow rate of 3000 kg / h to 3500 kg / h.

[0040] In some embodiments, the conditions for pyrolysis treatment include a flue gas velocity of 90 m / s to 110 m / s in the reactor.

[0041] In some embodiments, the pyrolysis treatment conditions include a reaction time of 30 ms to 60 ms.

[0042] The present invention also provides a conductive carbon black, which is prepared by the above-described preparation method.

[0043] The present invention also provides a semiconductive shielding material, comprising the above-mentioned conductive carbon black.

[0044] The present invention has the following beneficial effects:

[0045] This invention applies an external electric field to confine alkali metal ions in the feed oil to the bottom of the preheater, preventing them from participating in the carbon black formation process, thereby reducing the impact of alkali metal ions on the carbon black structure.

[0046] The method of this invention only improves the primary structure of carbon black without affecting its secondary structure.

[0047] The method of the present invention does not limit the type of raw oil. The higher the concentration of alkali metal ions in the raw oil, the greater the effect of the present invention on improving the structure.

[0048] This invention can also limit the generation of impurity metal ions from rust produced after equipment corrosion or oxidation entering the oil. Attached Figure Description

[0049] Figure 1 This is a side view of the production apparatus of the present invention;

[0050] Figure 2 This is a schematic cross-sectional view of the production apparatus of the present invention. Detailed Implementation

[0051] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0053] The structure of carbon black refers to the aggregation state and degree of its basic particles, encompassing both primary and secondary structures. The primary structure, also known as an aggregate, is the basic structural unit of carbon black, consisting of chain-like branches where carbon black particles are bonded together by chemical bonds. The secondary structure is a looser structure formed by the aggregation of carbon black aggregates through physical adsorption or van der Waals forces. This secondary structure is less stable and easily altered by compression, granulation, or mixing processes. High-structure conductive carbon black exhibits better performance in terms of hardness, tensile stress, and conductivity. Therefore, improving the primary structure of carbon black is a key research focus.

[0054] According to the Coulomb force formula, F = kq1q2 / R 2 The electrostatic repulsion between particles is proportional to the square of the charge. The aggregation of carbon black particles is significantly inhibited by the presence of sodium and potassium ions, thus affecting the primary structure of carbon black during formation. Therefore, in the carbon black production process, potassium and sodium ions in the feedstock oil affect the aggregation of carbon black ions during the carbon black reaction, reducing the carbon black structure and making the structure difficult to control.

[0055] A study has disclosed a production scheme for liquid carbon black feedstock oil treated with organic solvents, including two preferred methods for removing alkali metal ions: One method involves extracting and removing alkali metal ions from the refined filter oil using inorganic solvents, such as inorganic acids and deionized water; the other method involves first acid extraction of the refined filter oil, specifically using dilute hydrochloric acid to extract alkali metal ions, and then using a static pipeline mixer to convert water-soluble and insoluble alkali metal ions into water-soluble ions, resulting in an oleic acid mixture. This mixture is then subjected to oil-water separation using an electrostatic dewatering device to obtain an acid-extracted oil. Finally, the acid-extracted oil is washed with water, and then washed again using a static pipeline mixer to obtain an oil-water mixture. This mixture is then subjected to oil-water separation using an electrostatic dewatering device to obtain a de-alkali oil. However, this process is relatively complex, and the use of other chemical reagents inevitably introduces other impurities, affecting other properties of the carbon black.

[0056] Other methods include using feedstock oil with high aromatic hydroxyl content, but this often leads to a significant increase in production costs. Another example is using a larger combustion furnace spray angle, which has the disadvantage that the effect of improving the carbon black structure is not significant enough. Traditional methods for removing alkali metal ions also tend to introduce other impurities.

[0057] Based on this, the present invention provides a method for purifying carbon black feedstock oil, comprising the following steps:

[0058] The carbon black feedstock oil is pretreated to prepare crude carbon black feedstock oil.

[0059] The crude carbon black feedstock oil is subjected to electric field treatment.

[0060] In some of these examples, the feedstock oil includes one or more of coal tar, carbon black oil, anthracene oil, and ethylene tar.

[0061] In the examples of this invention, coal tar has the advantages of high yield, high output, and low price; carbon black oil has the advantages of good stability, high yield, and low price; anthracene oil has the advantages of good stability, concentrated fractions, and few impurities; and ethylene tar has the advantages of good stability, high light fractions, and few impurities.

[0062] The technical solution provided by this invention does not limit the type of raw material oil. The more alkali metal ion impurities there are, the greater the effect of this invention on improving the structure.

[0063] In this invention, the moisture, ash, toluene-insoluble matter, and density of the feedstock oil significantly affect the quality and yield of carbon black. Moisture in the feedstock oil affects the drying time and efficiency of carbon black, as well as its purity and quality. Excessive moisture can lead to agglomeration and loss of carbon black during the drying process, impacting yield and quality. Ash in the feedstock oil refers to the residual amount of non-combustible materials. The presence of ash not only increases the cost of the feedstock oil but also generates pollution and noise during carbon black production, while simultaneously reducing the purity and quality of the carbon black. Toluene-insoluble matter in the feedstock oil refers to solid impurities that are difficult to dissolve in toluene or other solvents. These impurities may become foreign matter mixed into the carbon black during production, affecting its physical and chemical properties. The density of the feedstock oil significantly impacts its distillation characteristics, flowability, and flammability. Low density leads to easy volatilization, which is detrimental to carbon black production and stability, while excessively high density can result in poor flowability, affecting the uniformity of the carbon black.

[0064] In some of these examples, the ash content of the coal tar is ≤0.1%.

[0065] In some of these examples, the moisture content of the coal tar is ≤4.0%.

[0066] In some of these examples, the toluene-insoluble content of the coal tar is ≤6.0%.

[0067] In some of these examples, the coal tar has a density of 1.16 g / cm³ at 20°C. 3 ~1.19g / cm 3 .

[0068] In some of these examples, the ash content of the carbon black oil is ≤0.1%.

[0069] In some of these examples, the moisture content of the carbon black oil is ≤0.5%.

[0070] In some of these examples, the toluene-insoluble content of the carbon black oil is ≤6.0%.

[0071] In some of these examples, the carbon black oil has a density of 1.19 g / cm³ at 20°C. 3 ~1.21g / cm 3 .

[0072] In some of these examples, the anthracene oil is derived from the 300°C–360°C fraction of coal tar.

[0073] In some of these examples, the ash content of the anthracene oil is ≤0.02%.

[0074] In some of these examples, the anthracene oil has a moisture content of ≤0.5%.

[0075] In some of these examples, the toluene-insoluble content of the anthracene oil is ≤0.2%.

[0076] In some of these examples, the anthracene oil has a density of 1.12 g / cm³ at 20°C. 3 ~1.14g / cm 3 .

[0077] In some of these examples, the ash content of the ethylene tar is ≤0.03%.

[0078] In some of these examples, the moisture content of the ethylene tar is ≤0.5%.

[0079] In some of these examples, the toluene-insoluble content of the ethylene tar is ≤0.3%.

[0080] In some of these examples, the ethylene tar has a density of 1.06 g / cm³ at 20°C. 3 ~1.10g / cm 3 .

[0081] In some of these examples, the feedstock oil comprises a mixture of anthracene oil and ethylene tar, wherein the mass ratio of the anthracene oil to the ethylene tar is ≥7:3.

[0082] In some of these examples, preprocessing includes the following steps:

[0083] The raw material oil is heated to 80℃~90℃, and the crude carbon black raw material oil is prepared by sedimentation treatment and solid-liquid separation treatment.

[0084] Specifically, pretreatment can remove residues and impurities from the raw oil.

[0085] In some of these examples, the steps involved in the electric field treatment include:

[0086] An electric field is applied to the crude carbon black feedstock oil to cause the alkali metal ions in the crude carbon black feedstock oil to move in a specific direction.

[0087] Crude crude oil contains a relatively high amount of alkali metal ions such as potassium (K). + Na + During the carbon black formation process, alkali metal ions present in the feed oil can increase the electropositivity of carbon black particles. Due to the repulsion of like charges, the collision frequency between primary carbon black particles and other particles is reduced, leading to a simplification of the structure of aggregates and aggregates. Therefore, alkali metal ions in the feed oil have a great influence on the carbon black structure, which in turn affects the conductivity of conductive carbon black.

[0088] The researchers of this invention have creatively applied an electric field to the crude carbon black feedstock oil, causing the alkali metal ions in the crude carbon black feedstock oil to move in a directional manner, so that the alkali metal ions do not participate in the carbon black preparation process, thereby reducing the influence of alkali metal ions on the carbon black structure.

[0089] Specifically, please refer to Figure 1 and Figure 2 As shown, the present invention applies an electric field of a certain intensity to the upper and lower sides of the feedstock oil preheater and reactor, wherein the top of the preheater and reactor is the positive electrode of the electric field and the bottom is the negative electrode of the electric field, thereby confining the alkali metal ions in the crude feedstock oil to the bottom of the preheater and reactor.

[0090] In some of these examples, the alkali metal ions include one or more of potassium and sodium ions, and 1 ppm of the alkali metal ions corresponds to an electric field strength ≥10 V / m.

[0091] In some of these examples, the alkali metal ions are a mixture of potassium and sodium ions, and the electric field strength corresponding to 1 ppm of the alkali metal ions is ≥50 V / m.

[0092] Specifically, the content of potassium ions and sodium ions was determined using atomic absorption spectrometry.

[0093] In some specific examples, the feed oil is preheated to 200°C to 220°C in the preheater and then left to stand for 10 to 15 minutes before being sprayed into the reactor through an oil nozzle.

[0094] This invention also provides a method for preparing conductive carbon black, comprising the following steps:

[0095] Provide carbon black feedstock oil, and purify the carbon black feedstock oil according to the above-mentioned purification method to prepare pure feedstock oil;

[0096] The conductive carbon black is prepared by applying an electric field to the pure raw oil for pyrolysis, granulation, desorption, and refining.

[0097] In some of these examples, crude carbon black is prepared by pyrolysis, with pyrolysis conditions including an air-to-natural gas volume ratio of (17-20):1, for example, 17:1, 18:1, 19:1 or 20:1, preferably 17:1.

[0098] In some examples, the conditions for pyrolysis treatment include increasing the combustion temperature of the reactor combustion section to 1600°C to 1800°C, for example, 1600°C, 1650°C, 1700°C, 1750°C or 1800°C, preferably 1600°C.

[0099] In some examples, the conditions for the pyrolysis treatment include a feedstock flow rate of 3000 kg / h to 3500 kg / h, for example, 3000 kg / h, 3100 kg / h, 3200 kg / h, 3300 kg / h, 3400 kg / h or 3500 kg / h, preferably 3000 kg / h.

[0100] In some of these examples, the conditions for the pyrolysis treatment include a flue gas velocity of 90 m / s to 110 m / s in the reactor, for example, 90 m / s, 95 m / s, 100 m / s, 105 m / s or 110 m / s, preferably 100 m / s.

[0101] In some of these examples, the pyrolysis treatment conditions include a reaction time of 30 ms to 60 ms, for example, 30 ms, 40 ms, 50 ms or 60 ms, preferably 30 ms.

[0102] In this invention, high speed and high temperature result in small carbon black pyrolysis particle size. By adjusting the pyrolysis reaction time, the structure of carbon black can be improved, making the chain branch structure of carbon black longer and less prone to breakage at high temperatures, thereby improving the electrical conductivity of carbon black at high temperatures.

[0103] In some examples, a carbon black collection step is included after the carbon black pyrolysis reaction and before granulation. Specifically, the collection step includes: the carbon black generated in the reactor is sprayed with room temperature pure water to cool and terminate the reaction, collected through a filter bag, and then fed into a conveying pipeline and collected into a pulverized carbon tank.

[0104] In some of these examples, the binder for the granulation process is sodium lignosulfonate.

[0105] In some of these examples, a drying process is included after granulation and before desorption.

[0106] Specifically, the drying process involves drying the granulated carbon black using a dryer at a temperature of 200℃ to 300℃ for 5 to 30 minutes. The moisture from the dried carbon black is then removed by a fan, resulting in a final temperature of approximately 230℃.

[0107] In some of these examples, the dried carbon black enters a degasser for desorption. Nitrogen gas is introduced into the carbon black degasser to heat the carbon black under nitrogen protection and hold it for 30 to 35 minutes to remove oxygen-containing groups and some small molecules from the surface of the carbon black. After cooling to 280°C to 320°C, the surface of the carbon black is modified with a carbon black surface treatment agent and then enters a cooling device.

[0108] In some of these examples, the carbon black surface treatment agent includes one or more of vinyltriethoxysilane, γ-aminopropyltriethoxysilane, or vinyltri(methoxyethoxy)silane.

[0109] In some examples, the refining process includes passing the desorbed carbon black through refining equipment such as a slag remover, screening machine, air screen and multi-stage magnetic separator to separate and remove impurities, carbon black lumps, fine powder, rust and so on, leaving carbon black with uniform particles.

[0110] In some of these examples, the refined carbon black was tested for oil absorption value and compression oil absorption value.

[0111] In this invention, under specified test conditions, the volume (cm³) of di-n-butyl phthalate (DBP) absorbed by 100g of carbon black is measured. 3 The oil absorption value (DBP) of carbon black is calculated by measuring the void volume between carbon black aggregates. Therefore, it is a measure of the degree of carbon black aggregation and agglomeration. The measured oil absorption value represents the sum of the primary and secondary structures of the carbon black. If the carbon black is compressed under a certain pressure to eliminate the secondary structure caused by agglomeration, the measured oil absorption value represents the primary structure of the carbon black. This method is called the compression oil absorption value determination method.

[0112] Under the same particle size and specific surface area, a higher oil absorption value usually indicates a higher structure of carbon black.

[0113] The present invention also provides a conductive carbon black, which is prepared by the above-described preparation method.

[0114] The present invention also provides a semiconductive shielding material, comprising the above-mentioned conductive carbon black.

[0115] The following are specific examples.

[0116] The following examples use a mixture of anthracene oil and ethylene tar as the feedstock. However, using a single type of feedstock with similar physicochemical properties can also achieve the technical effects of this application.

[0117] Example 1

[0118] This embodiment provides a conductive carbon black and its preparation method.

[0119] (1) Selection of raw material oil: The raw material oils used are anthracene oil and ethylene tar, with a mass ratio of 7:3. The anthracene oil has an ash content of 0.02%, a moisture content of 0.4%, a toluene-insoluble content of 0.2%, and a density of 1.14 g / cm³ at 20°C. 3 The potassium ion content is 1.2 ppm, and the sodium ion content is 4.3 ppm; the ethylene tar has an ash content of 0.02%, a moisture content of 0.3%, a toluene-insoluble content of 0.3%, and a density of 1.064 g / cm³. 3 Potassium ion content = 0.9 ppm, sodium ion content = 8.4 ppm.

[0120] (2) Treatment of non-alkali metal impurities in raw oil: The raw oil is heated to 80°C, and after mixing, settling and filtration, residues and impurities are removed. The raw oil is then transported to the raw oil preheater through the raw oil pipeline and preheated to above 200°C. Finally, it is sprayed into the reactor through the oil nozzle.

[0121] (3) Treatment of alkali metal impurities in feedstock oil: An electric field of 100V / m is applied above and below the feedstock oil preheater and the reactor, with the direction of the electric field being positive at the top and negative at the bottom. After the feedstock oil is preheated to above 200℃ in the preheater, it is allowed to stand for 10 minutes, and then sprayed into the reactor through the oil nozzle.

[0122] (4) Preparation of carbon black: In a multi-stage reactor, the volume ratio of air to natural gas is 17:1. The combustion temperature of the combustion section of the reactor is 1600℃, the flow rate of the raw oil is 3000kg / h, the flue gas velocity in the reactor is 100m / s, and the reaction time is 30ms. The raw oil is subjected to a cracking reaction at this speed and temperature to prepare carbon black.

[0123] (5) Collection of carbon black: The carbon black generated in the reactor is sprayed into room temperature pure water to cool and terminate the reaction. After being collected by the filter bag, it enters the conveying pipeline and is collected in the carbon powder tank to obtain crude carbon black.

[0124] (6) Adding binder for granulation: The coarse carbon black in the powdered carbon tank is fed into the granulator evenly through the feed pump. The binder in the granulator is an aqueous solution prepared at a weight percentage of 5%. The binder is mixed with the granulation water at the inlet of the granulator by a static mixer through a metering pump. The flow rate of the binder metering pump is 80 kg / h, the flow rate of the granulation water pump is 6200 kg / h, and the binder is sodium lignosulfonate.

[0125] (7) Carbon black drying and desorption: The granulated carbon black is dried by a dryer. The water vapor after drying is removed by a fan. The temperature of the dried carbon black reaches 230℃. The dried carbon black enters a degasser for desorption. Nitrogen gas is introduced into the carbon black degasser to heat the carbon black in a nitrogen-protected environment and keep it for 30 minutes to remove oxygen-containing groups and some small molecules on the surface of the carbon black. After cooling to 300℃, the carbon black surface is modified with a carbon black surface treatment agent and then enters a cooling device. The carbon black surface treatment agent is vinyltriethoxysilane.

[0126] (8) Carbon black refining: Before entering the storage tank, the carbon black passes through refining equipment such as a slag remover, screening machine, air screen and multi-stage magnetic separator to separate and remove impurities, carbon black lumps, fine powder, rust and so on, leaving carbon black with uniform particles.

[0127] (9) Measurement of oil absorption value and compression oil absorption value: Take a sample of refined carbon black and measure its oil absorption value. The result is the arithmetic mean of two test results obtained under repeatability conditions. If the absolute difference between the two test results exceeds 1, the test needs to be repeated.

[0128] Oil absorption value measurement method: determined according to the method described in GB / T 3780.2-2017.

[0129] Compression oil absorption value measurement method: determined according to the method described in GB / T 3780.4-2017.

[0130] Example 2

[0131] The preparation method of Example 2 is basically the same as that of Example 1, except that the electric field strength applied to the feed oil preheater and the reactor in Example 2 is 200V / m.

[0132] Example 3

[0133] The preparation method of Example 3 is basically the same as that of Example 1, except that the electric field strength applied to the feed oil preheater and the reactor in Example 3 is 300V / m.

[0134] Example 4

[0135] The preparation method of Example 4 is basically the same as that of Example 1, except that the electric field strength applied to the feed oil preheater and the reactor in Example 4 is 400V / m.

[0136] Example 5

[0137] The preparation method of Example 5 is basically the same as that of Example 1, except that the electric field strength applied to the feed oil preheater and the reactor in Example 5 is 500V / m.

[0138] Example 6

[0139] The preparation method of Example 6 is basically the same as that of Example 1, except that the electric field strength applied to the feed oil preheater and the reactor in Example 6 is 50V / m.

[0140] Example 7

[0141] The preparation method of Example 7 is basically the same as that of Example 1, except that the electric field strength applied to the feed oil preheater and the reactor in Example 7 is 30V / m.

[0142] Example 8

[0143] The preparation method of Example 8 is basically the same as that of Example 1, except that: in Example 8, an electric field strength of 100V / m is applied above and below the preheater, while no electric field is applied above and below the reactor.

[0144] Comparative Example 1

[0145] The preparation method of Comparative Example 1 is basically the same as that of Example 1, except that Comparative Example 1 was not subjected to electric field treatment, and the electric field strength applied to the feed oil preheater and the upper and lower parts of the reactor was 0V / m.

[0146] The performance test results of the carbon black prepared by the methods of Examples 1-8 and Comparative Example 1 are listed in Table 1 below:

[0147] Table 1

[0148]

[0149] As can be seen from Examples 1 to 7 in Table 1, with the increase of the electric field strength applied to the preheater, the DBP value and compressed DBP value of the generated carbon black gradually increase. When an electric field strength of ≥10V / m is applied according to the alkali metal ion strength corresponding to 1ppm, most potassium and sodium ions are confined to the bottom of the preheater and the reactor, and very few potassium and sodium ions participate in the formation of carbon black. Further, from Examples 4 and 5, it can be seen that when the applied electric field strengths are 400V / m and 500V / m, respectively, that is, when an electric field strength of ≥50V / m is applied according to the alkali metal ion strength corresponding to 1ppm, the residual potassium and sodium ions have basically no impact on the structure of the carbon black. From Examples 1 and 8, it can be seen that in Example 8, only a certain electric field strength is applied to the feed oil of the preheater, and most potassium and sodium ions are confined to the bottom of the preheater. A small portion of potassium and sodium ions may affect the formation of carbon black in the reactor. Comparing the oil absorption value and the compression oil absorption value, it can be seen that the difference between the oil absorption value and the compression oil absorption value in the examples and the comparative examples is basically the same. This is because the present invention only improves the primary structure of carbon black without affecting the secondary structure of carbon black.

[0150] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0151] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing conductive carbon black, characterized in that, Includes the following steps: A carbon black feedstock oil is provided, and the carbon black feedstock oil is pretreated to prepare a crude carbon black feedstock oil. The pretreatment includes the following steps: heating the carbon black feedstock oil to 80℃~90℃, and preparing the crude carbon black feedstock oil by sedimentation treatment and solid-liquid separation treatment. The carbon black feedstock oil includes one or more of coal tar, carbon black oil, anthracene oil and ethylene tar. Carbon black is prepared by applying an electric field to the crude carbon black feedstock oil for pyrolysis treatment: A certain intensity of electric field is applied to the upper and lower sides of the feedstock oil preheater and reactor, with the top of the preheater and reactor being the positive electrode and the bottom the negative electrode, thereby confining alkali metal ions in the crude feedstock oil to the bottom of the preheater and reactor; the alkali metal ions include potassium ions and / or sodium ions, and the electric field strength corresponding to 1 ppm of the alkali metal ions is ≥10V / m; the feedstock oil is preheated to 200℃~220℃ in the preheater and then allowed to stand for 10min~15min, subsequently sprayed into the reactor through an oil nozzle; the pyrolysis treatment conditions include: an air-to-natural gas volume ratio of (17~20):1; a combustion temperature in the reactor combustion section increased to 1600℃~1800℃; a feedstock oil flow rate of 3000kg / h~3500kg / h; a flue gas velocity in the reactor of 90m / s~110m / s; and a reaction time of 30ms~60ms; After pyrolysis, the carbon black is collected and subjected to granulation, desorption, and refining processes to obtain the conductive carbon black.

2. The method according to claim 1, characterized in that, The alkali metal ions are a mixture of potassium and sodium ions, and the electric field strength corresponding to 1 ppm of the alkali metal ions is ≥50V / m.

3. The method according to claim 1, characterized in that, The coal tar contains ≤0.1% ash, ≤4.0% moisture, ≤6.0% toluene-insoluble matter, and has a density of 1.16 g / cm³ at 20°C. 3 ~1.19g / cm 3 .

4. The method according to claim 1, characterized in that, The carbon black oil has an ash content ≤0.1%, moisture content ≤0.5%, toluene-insoluble matter ≤6.0%, and a density of 1.19 g / cm³ at 20°C. 3 ~1.21g / cm 3 .

5. The method according to claim 1, characterized in that, The anthracene oil is derived from the 300℃~360℃ fraction of coal tar; ash content ≤0.02%; moisture ≤0.5%; toluene-insoluble matter ≤0.2%; density at 20℃ is 1.12 g / cm³. 3 ~1.14g / cm 3 .

6. The method according to claim 1, characterized in that, The ethylene coke has an ash content ≤0.03%; moisture content ≤0.5%; toluene-insoluble matter ≤0.3%; and a density of 1.06 g / cm³ at 20°C. 3 ~1.10g / cm 3 .

7. The method according to claim 1, characterized in that, The feedstock oil comprises a mixture of anthracene oil and ethylene tar, wherein the mass ratio of the anthracene oil to the ethylene tar is ≥7:3.

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