Composite flocculant for deeply removing asphaltene and colloid in carbon black raw oil and application method of composite flocculant

Abstract

The invention discloses a composite flocculant for deeply removing asphaltene and colloid in carbon black raw oil, which mainly adopts 1-vinyl-3-butylimidazolium tetrafluoroborate as a main flocculant, cocamidopropyl hydroxysulfobetaine as a first synergist and salicylaldoxime as a second synergist to form the composite flocculant, after carbon black raw oil is subjected to flocculation pretreatment by using the composite flocculant, the obtained purified oil is subjected to furfural refining, so that high-purity refined carbon black raw oil can be obtained, the dependence of high-end carbon black production on anthracene oil can be broken through, and high-performance carbon black can be stably produced by using cheap ethylene tar; therefore, the method has good industrial value and application prospect.

Description

Technical Field

[0001] This invention belongs to the field of oil processing, specifically relating to a composite flocculant for deep removal of asphaltenes and gums from carbon black feedstock oil and its application method. Background Technology

[0002] Carbon black is an indispensable functional nanomaterial in industries such as rubber, plastics, and inks. In the tire industry, carbon black plays a decisive role in the reinforcing properties, abrasion resistance, and dynamic mechanical properties (such as rolling resistance) of rubber compounds. With the increasing global emphasis on "green tires" and energy conservation and environmental protection, the market demand for high-end carbon blacks (such as low rolling resistance carbon black, high abrasion-resistant carbon black, and high-purity conductive carbon black) is becoming increasingly urgent. These high-end carbon blacks require high structure, high purity, uniform aggregate morphology, and excellent dispersibility. However, high-quality carbon black heavily relies on high-quality feedstock oils.

[0003] Currently, the main feedstocks used in carbon black production are ethylene tar and coal tar-based anthracene oil. Anthracene oil, due to its high aromatic content and relatively few impurities, has always been an ideal raw material for producing high-quality carbon black. However, its resources are scarce, its price is high, and its supply is greatly affected by policies in the steel and coking industries, severely restricting cost control and stable production in the carbon black industry. Ethylene tar, as a byproduct of petroleum cracking, has a stable source and lower cost, making it an ideal alternative to anthracene oil. However, untreated ethylene tar contains a large amount of gum, asphaltenes, quinoline insolubles, and metallic impurities such as vanadium and nickel. These harmful components can lead to a series of problems during carbon black production, including coking and clogging, deterioration of carbon black quality, and excessive ash content in the product.

[0004] To address the aforementioned issues, the industry has attempted various crude oil pretreatment technologies, but all have significant limitations: 1) Sedimentation and centrifugation: These methods can only remove some large mechanical impurities, and their removal efficiency for colloidal stable substances such as gums, asphaltenes, and micron-sized QI (quinoline insolubles) is extremely low and time-consuming; 2) Conventional flocculant treatment: While using inorganic salts (such as aluminum trichloride) or traditional polymeric flocculants can improve impurity removal rates, they introduce new metal ions (such as Al) into the oil. 3+ ) or impurities, which also lead to an increase in the ash content of the final carbon black product, making it unable to meet the requirements of high-end applications; 3) Single solvent refining (such as furfural refining): It can separate components with different solubility, but it is not very effective for stable colloidal systems, solid QI particles and metal complexes in raw oil. When directly processing inferior raw oil, it is easy to cause blockage of the extraction tower, large solvent consumption, and limited ability to remove metal impurities; 4) Hydrogenation treatment: Although it can deeply remove impurities, it has the problems of huge investment, harsh operating conditions (high temperature and high pressure) and extremely high energy consumption. Its high cost is difficult for carbon black production enterprises to bear.

[0005] In summary, current technologies lack a method for the economical and efficient deep removal of gums, asphaltenes, and metallic impurities from carbon black feedstock oil without introducing secondary pollution. This has resulted in the carbon black industry, particularly in the high-end carbon black sector, being long constrained by the supply bottleneck and cost pressures of high-quality raw materials. Therefore, developing a novel and targeted deep purification technology for feedstock oil is of paramount importance for breaking down barriers to high-end carbon black raw materials and enhancing the competitiveness of the entire industry. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a composite flocculant and its application method that can deeply, efficiently and economically remove gum, asphaltenes, quinoline insolubles and metal impurities from carbon black feedstock oil. This method can be used to prepare high-purity feedstock oil, thereby breaking the dependence of high-end carbon black production on anthracene oil and providing key technical support for the stable production of high-performance carbon black from inexpensive ethylene tar.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: The first objective of this invention is to protect a composite flocculant for deep removal of asphaltenes and gums from carbon black feedstock oil, which is composed of a main flocculant, a first synergist, and a second synergist.

[0008] Furthermore, the primary flocculant is 1-vinyl-3-butylimidazolium tetrafluoroborate.

[0009] Furthermore, the first synergist is the natural surfactant cocamidopropyl hydroxysulfonate.

[0010] Furthermore, the second synergist is salicylaldehyde oxime.

[0011] Furthermore, the mass percentage ratio of the main flocculant, the first synergist, and the second synergist is (80-50):(30-10):(20-5).

[0012] Preferably, the mass percentage ratio of the main flocculant, the first synergist, and the second synergist is (60-70):(26.6-20):(13.4-10).

[0013] A second objective of this invention is to protect a method for deep removal of asphaltenes and gums from carbon black feedstock using the aforementioned composite flocculant, comprising the following steps: 1) Flocculation pretreatment: After preheating the carbon black raw material oil, the first synergist, the second synergist and the main flocculant are added in sequence and stirred for flocculation. After settling, the upper purified oil is separated and collected. 2) Furfural refining: The upper purified oil obtained in step 1) is subjected to countercurrent extraction with furfural to separate the extract and the residue; the solvent of the obtained extract is recovered to obtain high-purity refined carbon black raw material oil.

[0014] Furthermore, the carbon black feedstock oil mentioned in step 1) includes ethylene tar.

[0015] Further, in step 1), the carbon black feedstock oil is preheated to 60-80℃.

[0016] Further, in step 1), after adding the first synergist, the second synergist, and the main flocculant, stir for 10-20 minutes each.

[0017] Furthermore, the settling time described in step 1) is 30-120 minutes.

[0018] Furthermore, in step 2), the volume ratio of furfural to the upper purified oil is 2:1.

[0019] Furthermore, the solvent recovery described in step 2) is carried out by vacuum distillation.

[0020] The third objective of this invention is to protect a purification system that utilizes the above-described method to purify carbon black feedstock oil.

[0021] Furthermore, the purification system sequentially includes a flocculation pretreatment unit and a furfural refining unit.

[0022] Furthermore, the flocculation pretreatment unit includes at least a preheater, a flocculation reactor, and an intermediate oil tank for receiving the upper purified oil, connected in sequence; the furfural refining unit includes at least an extraction tower and a furfural recovery and depressurization tower; the inlet of the extraction tower is connected to the intermediate oil tank, and its outlet is connected to the furfural recovery and depressurization tower.

[0023] The fourth objective of this invention is to protect the refined carbon black feedstock oil prepared by the above-described method or purification system, wherein the ash content is not higher than 0.001%, the gum content is not higher than 0.8%, and the asphaltene content is not higher than 1.6%.

[0024] Furthermore, the refined carbon black feedstock oil obtained can be used to produce high-end carbon black.

[0025] Furthermore, the high-end carbon black includes, but is not limited to, low rolling resistance carbon black, high abrasion-resistant carbon black, or conductive carbon black.

[0026] The main flocculant of this invention features densely packed cationic imidazole rings on its polymer chain, which strongly neutralize negatively charged asphaltene particles and compress the double layer. The imidazole rings and the aromatic lamellar structure of asphaltene generate a strong π-π stacking effect, ensuring firm adsorption. The long-chain polymer structure bridges multiple particles, forming large flocs. The synergist, cocamidopropyl hydroxysulfonate betaine, is a natural surfactant that effectively penetrates and disrupts stable colloids. It alters the wettability of asphaltene micelles, destroys the protective interfacial film, and transforms the asphaltene from a stable to an unstable state, thus creating opportunities for the adsorption of the main flocculant. This significantly reduces the amount of main flocculant required and is environmentally friendly. Asphaltene often contains metal porphyrin complexes such as vanadium and nickel, which are the core components of stable colloids and the source of their ash. The synergist, salicylaldehyde oxime, specifically chelates these metal ions, "removing" the colloid's framework and causing its structural collapse. This is a unique contribution of the component. After refining with furfural, the resulting oil has very low asphaltene content, high aromatic content, and low sulfur, nitrogen, and impurity content. It can be used as a special raw material for manufacturing high-performance, low-hysteresis, and high-purity specialty carbon black to meet the stringent requirements of high-end rubber products (especially green tires) and high-end conductive materials.

[0027] The significant advantages of this invention are: 1. Superior purification effect, achieving deep removal: This invention uses a unique ionic liquid (1-vinyl-3-butylimidazolium tetrafluoroborate) as the main flocculant, combined with two functionalized synergists (cocamidopropyl hydroxysulfonate betaine and salicylaldehyde oxime), forming a highly efficient composite system. This composite formula works synergistically to achieve "deep removal" of asphaltenes and gums in carbon black feedstock oil that seriously affect subsequent refining, laying a solid foundation for obtaining high-purity products.

[0028] 2. Breaking resource bottlenecks and achieving raw material substitution and cost reduction: This invention successfully realizes the substitution of traditional anthracene oil with inexpensive ethylene tar as a raw material for the production of high-performance carbon black. This breaks the heavy dependence of high-end carbon black production on anthracene oil resources, solves the problem of tight supply and high price of anthracene oil, and has significant strategic and economic value.

[0029] 3. Enhanced Product Grade: This invention, through pretreatment with a composite flocculant and subsequent furfural refining, yields high-purity refined carbon black raw material oil. Using this high-quality raw material enables the stable production of high-performance carbon black (such as specialized carbon black for high-end tires and conductive materials), thereby increasing the product's added value and market competitiveness.

[0030] 4. Excellent process synergy and enhancement of existing equipment: This technology adds a high-efficiency pretreatment process to existing furfural refining equipment, which can be perfectly integrated with the existing industrial process. By deeply removing impurities, it reduces the load on subsequent furfural refining units, improves the overall refining efficiency and the processing capacity of the equipment, and reduces the consumption of furfural solvent. Its economic benefits are significant and its application prospects are broad.

[0031] 5. Significantly reduced raw material costs (ethylene tar vs. anthracene oil), coupled with highly efficient purification, make the entire production process exceptionally economical. This provides the carbon black industry with a stable, low-cost, and high-quality production path, possessing excellent industrialization potential and broad market application prospects. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the apparatus of the present invention for deep removal of asphaltenes and gums from carbon black feedstock oil and preparation of refined carbon black feedstock oil. Detailed Implementation

[0033] like Figure 1 A purification system for deeply removing asphaltenes and gums from carbon black feedstock oil and preparing refined carbon black feedstock oil comprises, in sequence, a flocculation pretreatment unit and a furfural refining unit; the flocculation pretreatment unit includes a feedstock oil storage tank, a preheater, a flocculation reactor, and an intermediate oil tank; the furfural refining unit includes an extraction tower, a condenser, an extract tank, a residue tank, a furfural recovery tower, a furfural circulation tank, and a carbon black refined oil tank.

[0034] The method for deep removal of asphaltenes and gums from carbon black feedstock using the above-mentioned purification system and preparation of refined carbon black feedstock includes the following steps: 1) Flocculation pretreatment: The carbon black feedstock oil in the feedstock oil storage tank is sent to the preheater and preheated to 60-80℃ before being sent to the flocculation reactor. First, the first synergist, cocamidopropyl hydroxysulfonate betaine, is added and stirred for 10-20 min. Then, the second synergist, salicylaldehyde oxime, is added and stirred for 10-20 min. Next, the main flocculant, 1-vinyl-3-butylimidazolium tetrafluoroborate, is added and stirred for 10-20 min. After that, stirring is stopped, and the mixture is allowed to settle for 30-120 min. Then, the oil in the upper part of the flocculation reactor is pumped into the intermediate oil tank. The mass percentage ratio of the main flocculant, the first synergist and the second synergist used is (80-50):(30-10):(20-5). 2) Furfural refining: The oil from the intermediate oil tank is sent to the furfural extraction tower and subjected to countercurrent extraction with the solvent furfural (the volume ratio of furfural to the upper purified oil is 2:1). The extract flowing out from the top of the tower is sent to the furfural recovery tower. After vacuum distillation, the extract distilled from the top is sent to the furfural circulation tank through a condenser. The extract flowing out from the bottom is the refined carbon black feedstock oil. This oil has a high aromatic content and low sulfur, nitrogen and impurity content. It is sent to the carbon black refined oil tank for storage.

[0035] To determine the optimal mass ratio of the composite flocculant, the effects of different ratios of the main flocculant (A: 1-vinyl-3-butylimidazolium tetrafluoroborate), the first synergist (B: cocamidopropyl hydroxysulfonate), and the second synergist (C: salicylaldehyde oxime) on the purification effect were investigated (the carbon black feedstock was heated to 70℃, the total amount of composite flocculant added was 0.225 wt% of the carbon black feedstock mass, and the addition order was B first, then C, and finally A. Each stage was stirred for 15 minutes and allowed to settle for 60 minutes). The results are shown in Table 1.

[0036] Table 1 Comparison of the effects of different proportions of each component

[0037] Table 1 shows that Experimental Group 1 (A:B:C=66.6:22.2:11.1) exhibited the best overall performance, especially in ash removal rate, which is crucial for producing low-ash, high-end carbon black. Experimental Group 2 (A:B:C=66.6:25.0:8.4) achieved the highest removal rates of asphaltenes and gums, which is essential for preventing equipment blockage and ensuring the carbon black structure. However, when the proportion of main flocculant A is too low (e.g., in Experimental Group 7), insufficient charge neutralization and bridging capabilities lead to increased asphaltenes and gum content and decreased total essential oil yield. When the proportion of main flocculant A is too high and the proportions of synergists B and C are too low (e.g., in Experimental Groups 5 and 6), the synergistic effect of breaking the interfacial film and chelating metals cannot be fully utilized, also leading to increased asphaltenes and gum content and decreased total essential oil yield.

[0038] Based on the above experiments, the optimal mass ratio of the main flocculant, the first synergist, and the second synergist in the composite flocculant is (60-70):(26.6-20):(13.4-10). Within this range, efficient and deep removal of ash, asphaltene, and resins can be achieved simultaneously, while also ensuring the total yield of refined oil. Particularly preferred is a ratio of A:B:C = 66.6:25.0:8.4 when the focus is on maximizing the reduction of resin and asphaltene content. When the focus is on maximizing the reduction of ash content, a ratio of A:B:C = 66.6:22.2:11.1 can be used.

[0039] The following specific embodiments will make the technical solutions and advantages of the present invention clearer. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of the present invention, without departing from the spirit and scope of the present invention, should all be covered within the protection scope of the present invention.

[0040] The ethylene tar used in this embodiment is a mixture of ethylene tar and catalytic slurry produced by Sinochem Quanzhou Petrochemical.

[0041] The determination of ash content in carbon black raw material oil shall be in accordance with GB / T 41957-2022; the determination of sulfur content shall be in accordance with GB / T 41957-2022; the determination of nitrogen content shall be in accordance with GB / T 41957-2022; and the determination of four components shall be in accordance with NB-SH-T6087-2024. Example

[0042] Step 1: Flocculation Pretreatment 1) Take 1000g of ethylene tar into a 2000mL beaker, place it on an electric heating mantle and heat it to 70℃, and keep the temperature constant. Set the mechanical stirring speed to 300 rpm. First, add 0.5g of cocamidopropyl hydroxysulfonate betaine (first synergist) and stir continuously for 15 minutes. Then add 0.25g of salicylaldehyde oxime (second synergist) and stir continuously for 15 minutes. Then add 1.5g of 1-vinyl-3-butylimidazolium tetrafluoroborate (main flocculant) and stir continuously for 15 minutes. Stop stirring and let the mixture stand at 70℃ for 60 minutes to settle. Then carefully pour out the upper purified oil, weigh it and record the yield, and take a sample for analysis.

[0043] Step 2: Furfural refining The purified oil obtained in the first step is subjected to countercurrent furfural extraction in an extraction tower.

[0044] Operating conditions: Top temperature 65℃, bottom temperature 75℃, agent-to-oil ratio 2:1 (volume ratio).

[0045] The extract (refined oil and furfural) and the residue (colloids, asphaltenes and furfural) were separated.

[0046] The solvent was recovered from the extract using a vacuum distillation apparatus.

[0047] Operating conditions: Boiler temperature 165℃, top pressure 20kPa.

[0048] Furfural was recovered to obtain the final refined carbon black feedstock oil, which was weighed and analyzed.

[0049] The results showed that the purified oil yield in the flocculation pretreatment step was 94.5%. The final total yield of refined oil was 85.2% (relative to the original feedstock oil).

[0050] Comparative Example 1: Direct furfural refining (without pretreatment) Following the procedure in step two of the embodiment, ethylene tar is directly refined with furfural.

[0051] The results showed that due to the high QI and gum content in the raw material, the interface was unclear during extraction, making separation difficult. The final total yield of refined oil was 78.1%, and the quality was poor.

[0052] Comparative Example 2: Adding only the main flocculant In the first step, neither of the two synergists is added; that is, only 1.5g of 1-vinyl-3-butylimidazolium tetrafluoroborate is added as a flocculant, and the other operations are the same as in the example.

[0053] The results showed that the purified oil yield in the flocculation pretreatment step was 92.8%, and the final refined oil yield was 82.5% (relative to the original feedstock oil).

[0054] Comparative Example 3: Addition of primary flocculant and secondary synergist In the first step, cocamidopropyl hydroxysulfonate betaine (the first synergist) is not added. Instead, 0.25g of salicylaldehyde oxime (the second synergist) is added first, and the mixture is stirred continuously for 15 minutes. Then, 1.5g of 1-vinyl-3-butylimidazolium tetrafluoroborate (the main flocculant) is added. Other operations are the same as in the example.

[0055] The results showed that the purified oil yield in the flocculation pretreatment step was 93.4%, and the final refined oil yield was 83.3% (relative to the original feedstock oil).

[0056] Comparative Example 4: Addition of primary flocculant and first synergist In the first step, salicylaldehyde oxime (the second synergist) is not added. Instead, 0.25g of cocamidopropyl hydroxysulfonate betaine (the first synergist) is added first, and after stirring continuously for 15 minutes, 1.5g of 1-vinyl-3-butylimidazolium tetrafluoroborate (the main flocculant) is added. Other operations are the same as in the example.

[0057] The results showed that the purified oil yield in the flocculation pretreatment step was 94.2%, and the final refined oil yield was 84.5% (relative to the original feedstock oil).

[0058] Comparative Example 5: Mixture of added flocculants In the first step, a mixture of 1.5 g of 1-vinyl-3-butylimidazolium tetrafluoroborate (primary flocculant), 0.5 g of cocamidopropyl hydroxysulfonate betaine (first synergist), and 0.25 g of salicylaldehyde oxime (second synergist) was directly added to the ethylene tar. The mixture was then stirred continuously for 45 minutes. After stirring was stopped, the mixture was allowed to stand at 70°C to settle and separate. The supernatant purified oil was then carefully decanted, weighed, and the yield was recorded. Samples were taken for analysis. The second step was the same as in the previous example.

[0059] The results showed that the pretreated flocs were small and settled slowly, requiring a settling time of up to 90 minutes to barely separate. The purified oil yield in the flocculation pretreatment step was 90.5%, and the final total refined oil yield was 80.8% (relative to the original feedstock oil).

[0060] The key indicators of the final refined oil from all the above embodiments and comparative examples are summarized in Table 2.

[0061] Table 2 Comparison of Refined Oil Performance

[0062] As shown in Table 2, the refined oil obtained in the examples significantly outperformed the comparative examples in removing sulfur, nitrogen, asphaltenes, gums, and ash. Compared to the carbon black feedstock oil refined from furfural alone (Comparative Example 1), its asphaltenes content decreased directly from 10.2% to 1.6%, and its gum content decreased from 2.6% to 0.8%, resulting in a 10.4% increase in removal efficiency. Furthermore, the total yield of the refined oil also increased to 85.2%, a 7.1% improvement. This demonstrates that the flocculation pretreatment step greatly reduced the load on furfural refining, improving both product quality and final yield. Compared to Comparative Examples 2-5, the composite formulation of the flocculant and its addition order produced a significant "step-by-step synergistic, progressively breaking down" effect. Therefore, the use of the composite flocculant in this invention and its combination with furfural refining produced a synergistic effect, achieving deep purification.

[0063] In summary, this invention provides a composite flocculant through component compounding, which can deeply, efficiently, and economically remove gums, asphaltenes, quinoline insolubles, and metallic impurities from carbon black feedstock oil. When combined with furfural refining for the purification of carbon black feedstock oil, the resulting oil has extremely low gum and asphaltenes content, low sulfur, nitrogen, and impurity content, and high aromatic content, resulting in high quality. It can be used to manufacture high-performance, low-hysteresis, and high-purity specialty carbon black to meet the stringent requirements of high-end rubber products (especially green tires) and high-end conductive materials.

[0064] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A composite flocculant for deeply removing asphaltene and resin in a carbon black raw material oil, characterized by, The composite flocculant is composed of a main flocculant, a first synergist and a second synergist; the main flocculant is 1-vinyl-3-butyl imidazole tetrafluoroborate; the first synergist is cocamide propyl hydroxyl sulfobetaine; and the second synergist is salicylaldehyde oxime.

2. The composite flocculant according to claim 1, characterized by, The mass percentage ratio of the main flocculant, the first synergist and the second synergist is (80-50):(30-10):(20-5).

3. A method for deep removal of asphaltenes and resins from carbon black raw material oil using the composite flocculant according to claim 1, characterized in that, The method comprises the following steps: 1) flocculation pretreatment: after preheating the carbon black raw oil, the first synergist, the second synergist and the main flocculant are added in sequence for stirring flocculation, and then the purified oil in the upper layer is collected after standing and settling; 2) furfural refining: the purified oil in the upper layer obtained in step 1) is countercurrently extracted with furfural, and the obtained extract is subjected to solvent recovery to obtain refined carbon black raw oil.

4. The method of claim 3, wherein, In step 1), the carbon black raw oil is preheated to 60-80℃.

5. The method of claim 3, wherein, In step 1), the standing and settling time is 30-120 minutes.

6. The method of claim 3, wherein, In step 2), the volume ratio of furfural to the purified oil in the upper layer is 2:

1.

7. A purification system for a carbon black feed oil for carrying out the method according to any one of claims 3 to 6, characterized in that The purification system comprises a flocculation pretreatment unit and a furfural refining unit in sequence.

8. The purification system of claim 7, wherein, The flocculation pretreatment unit at least comprises a preheater, a flocculation reactor connected in sequence, and an intermediate oil tank for receiving the purified oil in the upper layer; The furfural refining unit at least comprises an extraction tower and a furfural recovery vacuum tower; the feed inlet of the extraction tower is connected with the intermediate oil tank, and the discharge outlet of the extraction tower is connected with the furfural recovery vacuum tower.

9. A refined carbon black stock oil prepared by the method of claim 3 or the purification system of claim 7. The ash content is not higher than 0.001%, the gum content is not higher than 0.8%, and the asphaltene content is not higher than 1.6%.

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