Method for removing vanadium and sulfur in petroleum coke

Abstract

The invention relates to the technical field of petroleum coke impurity removal, in particular to a method for removing vanadium and sulfur in petroleum coke. Petroleum coke contains vanadium and sulfur, and the method comprises the following steps: sequentially crushing and screening the petroleum coke to obtain petroleum coke powder; oxidizing an oxidizing agent and the petroleum coke powder so that vanadium and sulfur form soluble vanadium-containing salt and sulfur-containing salt to obtain pretreated petroleum coke powder; carrying out hydrothermal reaction on an alkaline solution and the pretreated petroleum coke powder, and removing vanadium-containing salt and sulfur-containing salt to obtain reaction slurry; carrying out solid-liquid separation on the reaction slurry to obtain a reaction solid-phase substance; and sequentially washing and drying the reaction solid-phase substance to obtain the purified petroleum coke. According to the method, firstly, insoluble vanadium and sulfur can be converted into soluble vanadate and sulfate through oxidation treatment, then the leaching efficiency of vanadium and sulfur in petroleum coke is enhanced through hydrothermal reaction, finally, residues of vanadate and sulfate are avoided through solid-liquid separation, washing, drying and other post-treatment, and the method is suitable for industrial production. The high removal rate of vanadium and sulfur in the petroleum coke powder is realized.

Description

Technical Field

[0001] This application relates to the field of petroleum coke impurity removal technology, and in particular to a method for removing vanadium and sulfur from petroleum coke. Background Technology

[0002] Petroleum coke is an important chemical raw material, mainly used in aluminum electrolysis, graphite electrodes, battery materials, and fuels. However, the deterioration of general-quality petroleum coke is worsening year by year. This deterioration is primarily manifested in the increasing vanadium and sulfur content, making it difficult to meet the production demands of these industries and resulting in a shortage of high-quality petroleum coke. Furthermore, much of this deteriorated petroleum coke is treated as fuel, leading to waste. Therefore, to meet the application requirements of petroleum coke, impurity removal processes can be used to reduce the vanadium and sulfur content, thereby improving the quality of deteriorated petroleum coke.

[0003] However, the main method for removing impurities from deteriorated petroleum coke is wet cleaning. By leaching the deteriorated petroleum coke with acid and alkali under normal pressure, vanadium and sulfur can be removed from the deteriorated petroleum coke. However, the removal rate of vanadium and sulfur in wet cleaning is low, making it difficult to achieve efficient removal of vanadium and sulfur from deteriorated petroleum coke. Summary of the Invention

[0004] This application provides a method for removing vanadium and sulfur from petroleum coke to solve the following technical problem: how to improve the removal rate of vanadium and sulfur from petroleum coke. In a first aspect, embodiments of this application provide a method for removing vanadium and sulfur from petroleum coke, wherein the petroleum coke contains vanadium and sulfur, the method comprising: The petroleum coke is crushed and screened sequentially to obtain petroleum coke powder; The petroleum coke powder is oxidized with an oxidant so that the vanadium and the sulfur form soluble vanadium-containing salts and sulfur-containing salts to obtain pretreated petroleum coke powder. The alkaline solution and the pretreated petroleum coke powder are subjected to a hydrothermal reaction to remove the vanadium-containing salt and the sulfur-containing salt, resulting in a reaction slurry. The reaction slurry was subjected to solid-liquid separation to obtain the reaction solid phase; The reaction solid was washed and dried sequentially to obtain purified petroleum coke.

[0005] Optionally, the volume V1 of the oxidant and the mass m1 of the petroleum coke powder satisfy: V1:m1 = (1 to 3):1, and if the unit of V1 is L, then the unit of m1 is g.

[0006] Optionally, the oxidant may be hydrogen peroxide and / or acetic acid oxidant.

[0007] Optionally, the oxidation treatment time is 4 to 6 hours.

[0008] Optionally, the molar concentration of the alkaline solution is from 2 mol / L to 5 mol / L.

[0009] Optionally, the alkaline solution may be a sodium hydroxide solution and / or a potassium hydroxide solution.

[0010] Optionally, the volume V2 of the alkaline solution and the mass m2 of the pretreated petroleum coke powder satisfy: V2:m2 = (1 to 7):1. If the unit of V2 is L, then the unit of m1 is g.

[0011] Optionally, the temperature of the hydrothermal reaction is 90°C to 130°C, and the time of the hydrothermal reaction is 60 min to 180 min.

[0012] Optionally, the petroleum coke powder has a particle size of ≥200 mesh.

[0013] Optionally, the number of washes is 3 to 5; and / or The drying temperature is 80°C to 90°C, and the drying time is 6 hours to 10 hours.

[0014] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a method for removing vanadium and sulfur from petroleum coke. The method first involves crushing and sieving the petroleum coke, exposing the vanadium and sulfur encased within the coke particles to the surface or near-surface of the particles, providing accessible pathways for subsequent oxidation and hydrothermal reactions. Next, the petroleum coke powder is oxidized using an oxidant, causing low-valence vanadium oxides, organic sulfur, and inorganic sulfur to be oxidized, forming soluble vanadium salts and sulfates. Then, a hydrothermal reaction is performed using an alkaline solution, which promotes the formation of soluble vanadates from the vanadium salts. Simultaneously, the alkaline environment created by the solution ensures the stable existence of vanadates and sulfates in the reaction slurry, preventing secondary adsorption of vanadates and sulfates by the petroleum coke particles. Finally, purification processes such as solid-liquid separation, washing, and drying prevent the recrystallization and adhesion of soluble vanadates and sulfates, removing most of the residual vanadates and sulfates from the surface of the reaction solid, ensuring the stability of the vanadium and sulfur removal rate, and ultimately obtaining purified petroleum coke with low vanadium and sulfur content. Attached Figure Description The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a method for removing vanadium and sulfur from petroleum coke, provided as an embodiment of this application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] The range descriptions used in this application, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "comprising" and others used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships involved in this document, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained by purchasing from the market or by existing methods.

[0019] Figure 1 An exemplary schematic diagram of a method for removing vanadium and sulfur from petroleum coke according to an embodiment of this application is shown; like Figure 1 As shown in the embodiments of this application, a method for removing vanadium and sulfur from petroleum coke is provided, wherein the petroleum coke contains vanadium and sulfur, and the method includes: S1. The petroleum coke is crushed and screened sequentially to obtain petroleum coke powder; S2. The oxidant and the petroleum coke powder are subjected to oxidation treatment so that the vanadium and the sulfur form soluble vanadium-containing salts and sulfur-containing salts to obtain pretreated petroleum coke powder; S3. The alkaline solution and the pretreated petroleum coke powder are subjected to a hydrothermal reaction to remove the vanadium-containing salt and the sulfur-containing salt, thereby obtaining a reaction slurry; S4. The reaction slurry is subjected to solid-liquid separation to obtain the reaction solid phase; S5. The reaction solids are washed and dried sequentially to obtain purified petroleum coke.

[0020] It should be noted that the hydrothermal reaction can be carried out under stirring conditions, with the stirring speed being 300 r / min.

[0021] It should be noted that this drying can be carried out in a vacuum drying oven or a forced-air drying oven.

[0022] It should be noted that this washing can be done using deionized water or a dilute alkaline solution.

[0023] It should be noted that the method for removing vanadium and sulfur from petroleum coke provided in this application embodiment addresses the core bottlenecks of vanadium and sulfur in petroleum coke—namely, their poor solubility, difficulty in contact, and difficulty in separation—through a comprehensive process design involving physical modification, chemical conversion, enhanced leaching, and refined post-treatment. This ultimately achieves highly efficient removal of vanadium and sulfur from petroleum coke. The specific mechanism is as follows: I. Physical pretreatment (crushing and sieving): This lays the foundation for oxidation treatment and hydrothermal reaction, and improves the contact efficiency between vanadium and sulfur and the reaction reagents.

[0024] In its raw state, petroleum coke is generally in block or granular form. Its dense internal pore structure allows vanadium (mostly in the form of low-valent vanadium oxides V₂O₃, V₃O₅, or vanadium sulfide VS₂) and sulfur (mostly organic sulfur, such as thiophene and sulfides; or inorganic sulfides, such as FeS₂) to be easily encapsulated by the coke matrix, making it difficult for oxidants and leaching agents to contact. Core function: After crushing and screening, the particle size of petroleum coke powder decreases and its specific surface area increases significantly. During the oxidation treatment stage, the high specific surface area and small particle size of petroleum coke powder can maximize the contact with the oxidant. During the crushing process, some of the pore structures of the petroleum coke powder are opened, exposing the vanadium and sulfur encased inside the petroleum coke powder to the surface or near-surface of the petroleum coke particles. This provides accessible channels for subsequent oxidation treatment and hydrothermal reactions, avoiding the localized problem of sufficient surface reaction but unreacted interior in the petroleum coke particles.

[0025] II. Oxidation Pretreatment: The core conversion step, solving the problem of the poor solubility of vanadium and sulfur.

[0026] The key reason why traditional impurity removal methods struggle to remove vanadium and sulfur from petroleum coke particles lies in the poor solubility of vanadium and sulfur in their phases: low-valence vanadium oxides (V... 3+ V 4+ Organic sulfur and some sulfides are insoluble in water or weakly alkaline solutions under normal conditions, making it impossible to separate vanadium and sulfur from petroleum coke powder through simple leaching. The core logic of oxidation treatment is to achieve the phase transformation of vanadium and sulfur: 1. Oxidizing agents (such as hydrogen peroxide and acetic acid oxidase) can oxidize low-valent vanadium oxides (V... 3+ V 4+ ) is oxidized to a higher valence vanadium salt (V 5+ Furthermore, high-priced vanadium salts are more chemically active and readily form soluble vanadates (such as NaVO3 and KVO3) in alkaline solutions, completely altering the insoluble properties of vanadium. 2. Oxidizing agents can oxidize organic sulfur (such as thiophene and sulfides) to inorganic sulfur (SO4). 2- It can also oxidize inorganic sulfides (such as FeS2) into soluble sulfates {such as Fe2(SO4)3}, while organic sulfur is the main form of sulfur in petroleum coke powder (accounting for 60% to 80%). Conventional methods are difficult to break the CS bond. Oxidation treatment with oxidants can directly destroy the stable structure of organic sulfur and convert it into inorganic sulfur form that is easily soluble in alkaline solutions. The oxidation process also slightly etches the surface of the petroleum coke powder, further increasing its porosity and allowing the subsequent alkaline solution to penetrate into the interior of the petroleum coke particles, achieving a comprehensive reaction between the surface and interior of the petroleum coke powder.

[0027] III. Alkaline hydrothermal leaching: Enhances the efficient separation of vanadium and sulfur in petroleum coke powder and improves the thoroughness of leaching during the hydrothermal reaction process.

[0028] The oxidation process converts vanadium and sulfur in petroleum coke powder into soluble salts, but these soluble salts need to be separated from the petroleum coke powder by leaching. The alkaline environment of the alkaline solution and the thermal environment of the hydrothermal reaction are key to improving the leaching efficiency of soluble salts in petroleum coke powder. 1. Targeted effects of alkaline environment: High-priced vanadium salts (V 5+ Under alkaline conditions, it can exist stably in alkaline solutions, forming soluble vanadates (such as NaVO3), thus preventing vanadates from redepositing into insoluble vanadium-containing oxides under neutral or acidic conditions. Sulfates {e.g. Na2SO4, Fe2(SO4)3} can remain soluble in alkaline solutions (or be converted into soluble sodium salts through acid-base reactions), preventing the sulfates from being re-adsorbed onto the surface of petroleum coke powder.

[0029] 2. The enhancing effect of hydrothermal conditions: High-temperature environments significantly enhance the reactivity of alkaline solutions, accelerate the diffusion and dissolution of soluble salts from the pores of petroleum coke powder, and improve the leaching efficiency of vanadium and sulfur. The hydrothermal environment can further disrupt the graphite-like layered structure of petroleum coke, break the chemical bonds between vanadium, sulfur and the coke matrix of petroleum coke powder, and allow the vanadium and sulfur originally embedded in the layers of petroleum coke powder to be completely released and leached out, thus solving the problem that the surface layer of petroleum coke particles is easy to remove but the deep layers are difficult to leach out.

[0030] IV. Post-treatment (solid-liquid separation + washing and drying): to avoid secondary residues of vanadium and sulfur and to ensure the upper limit of vanadium and sulfur removal rates.

[0031] In the reaction slurry obtained from the hydrothermal reaction, the solid surface of the petroleum coke powder may still adsorb some vanadates and sulfates. Direct drying will result in vanadium and sulfur residues, reducing the final removal rate of vanadium and sulfur in the petroleum coke. Solid-liquid separation (filtration and / or centrifugation) can quickly separate vanadium and sulfur-containing leachates from the solid phase of petroleum coke, preventing the recrystallization and adhesion of soluble salts. The washing step (using deionized water or dilute alkaline solution to wash multiple times) can remove most of the residual vanadates and sulfates on the surface of the reaction solid, ensuring that vanadium and sulfur are not re-adsorbed by petroleum coke powder. The drying process (vacuum drying, avoiding the decomposition of vanadates and sulfates in a high-temperature and oxygen-rich environment to form precipitates) ultimately yields purified petroleum coke with low vanadium and sulfur content, ensuring the stability of vanadium and sulfur removal rates.

[0032] In summary, the method for removing vanadium and sulfur from petroleum coke provided in this application embodiment is based on the synergistic effect of targeted conversion and enhanced separation. Specifically, vanadium and sulfur are first converted into different forms, then leached through a hydrothermal reaction, and finally the complete separation of vanadium and sulfur is achieved, thus specifically addressing the core problems of traditional impurity removal processes. 1. Traditional impurity removal processes (such as direct alkaline leaching or high-temperature calcination) do not transform the form of vanadium and sulfur in petroleum coke powder. Insoluble substances containing vanadium or sulfur cannot be effectively leached out, resulting in extremely low removal rates of vanadium and sulfur in petroleum coke. 2. The method provided in this application first converts insoluble vanadium and sulfur into soluble vanadates and sulfates through oxidation treatment. Then, it enhances the leaching efficiency of vanadium and sulfur in petroleum coke through hydrothermal reaction. Finally, it avoids the residue of vanadates and sulfates through post-treatment such as solid-liquid separation, washing, and drying, thus achieving a high removal rate of vanadium and sulfur from petroleum coke powder. At the same time, the low-temperature hydrothermal reaction avoids the loss of calorific value caused by excessive oxidation of petroleum coke powder, thus balancing the removal rate of vanadium and sulfur with the industrial use value of petroleum coke powder, achieving a balance between environmental protection and economic benefits.

[0033] In some alternative embodiments, the volume V1 of the oxidant and the mass m1 of the petroleum coke powder satisfy: V1:m1 = (1 to 3):1, and if the unit of V1 is L, then the unit of m1 is g.

[0034] In these embodiments, the oxidant with a volume-to-mass ratio of (1 to 3):1 can fully react with the low-valence vanadium oxides, organic sulfur and inorganic sulfur in the petroleum coke powder to form soluble vanadium salts and sulfates. This facilitates the further conversion of vanadium salts into soluble vanadates during the subsequent hydrothermal reaction and promotes the separation of vanadates and sulfates from the petroleum coke powder.

[0035] The volume V1 of the oxidant can be 1, 1.5, 2, 2.5 or 3.0.

[0036] In some alternative embodiments, the oxidant is hydrogen peroxide and / or acetic acid oxidant.

[0037] In these embodiments, hydrogen peroxide and / or acetic acid oxidant are used as oxidants. On the one hand, hydrogen peroxide and acetic acid oxidant are low in cost, which can save on the production cost of oxidation treatment. On the other hand, liquid hydrogen peroxide and acetic acid oxidant can penetrate into the interior of petroleum coke particles more quickly, achieving a comprehensive reaction on the surface and inside of the petroleum coke particles.

[0038] In some alternative embodiments, the oxidation treatment lasts for 4 to 6 hours.

[0039] In these embodiments, an oxidation treatment lasting 4 to 6 hours allows the oxidant to fully react with the low-valence vanadium oxides, organic sulfur, and inorganic sulfur in the petroleum coke powder to form soluble vanadium salts and sulfates.

[0040] The oxidation treatment time can be 4h, 4.5h, 5.0h, 5.5h or 6.0h.

[0041] In some alternative embodiments, the molar concentration of the alkaline solution is from 2 mol / L to 5 mol / L.

[0042] In these embodiments, an alkaline solution with a molar concentration of 2 mol / L to 5 mol / L can convert the vanadium-containing salt obtained from the oxidation treatment into soluble vanadate and allow the sulfate to exist stably in the alkaline solution. At the same time, the alkaline environment formed by the alkaline solution can prevent vanadate and sulfate from being re-adsorbed onto the surface of the petroleum coke powder, which is beneficial for subsequent solid-liquid separation, washing and drying.

[0043] The molar concentration of the alkaline solution can be 2 mol / L, 2.5 mol / L, 3.0 mol / L, 3.5 mol / L, 4.0 mol / L, 4.5 mol / L, or 5.0 mol / L.

[0044] In some alternative embodiments, the alkaline solution is a sodium hydroxide solution and / or a potassium hydroxide solution.

[0045] In these embodiments, using sodium hydroxide solution and / or potassium hydroxide solution as alkaline solution can convert the vanadium-containing salt obtained from the oxidation treatment into soluble vanadate and allow the sulfate to exist stably in the alkaline solution. At the same time, the alkaline environment formed by the alkaline solution can prevent vanadate and sulfate from being re-adsorbed onto the surface of petroleum coke powder, which is beneficial for subsequent solid-liquid separation, washing and drying.

[0046] In some alternative embodiments, the volume V2 of the alkaline solution and the mass m2 of the pretreated petroleum coke powder satisfy: V2:m2 = (1 to 7):1, and if the unit of V2 is L, then the unit of m1 is g.

[0047] In these embodiments, an alkaline solution with a volume-to-mass ratio of (1 to 7):1 for the pretreated petroleum coke powder can create an alkaline environment. This alkaline environment allows the vanadium-containing salt obtained from the oxidation process to be converted into soluble vanadate, and promotes the stable presence of sulfate in the alkaline solution, which is beneficial for subsequent solid-liquid separation, washing, and drying.

[0048] The volume V2 of the alkaline solution can be 1, 2, 3, 4, 5, 6 or 7.

[0049] In some alternative embodiments, the hydrothermal reaction temperature is 90°C to 130°C, and the hydrothermal reaction time is 60 min to 180 min.

[0050] In these embodiments, hydrothermal reactions at temperatures of 90°C to 130°C and for durations of 60 min to 180 min can significantly enhance the reactivity of alkaline solutions and disrupt the graphite-like layered structure of petroleum coke. This accelerates the diffusion and dissolution of soluble vanadates and sulfates from the pores and interlayers of petroleum coke powder, thereby improving the leaching efficiency of vanadium and sulfur and solving the problem that the surface layer of petroleum coke particles is easy to remove but the deeper layers are difficult to leach.

[0051] The temperature of the hydrothermal reaction can be 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃ or 130℃.

[0052] The hydrothermal reaction time can be 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, 150 min, 160 min, 170 min, or 180 min.

[0053] In some alternative embodiments, the petroleum coke powder has a particle size of ≥200 mesh.

[0054] In these embodiments, petroleum coke powder with a particle size ≥200 mesh has a high specific surface area. The petroleum coke powder with a high specific surface area can have maximum contact with the oxidant during oxidation treatment and undergo oxidation treatment. At the same time, the petroleum coke powder with a high specific surface area can facilitate the penetration of alkaline solution in hydrothermal reaction, so that vanadium and sulfur in petroleum coke powder can be fully converted into soluble vanadates and sulfates.

[0055] In some alternative embodiments, the number of washes is 3 to 5; and / or The drying temperature is 80°C to 90°C, and the drying time is 6 hours to 10 hours.

[0056] In these embodiments, washing 3 to 5 times effectively removes most of the residual vanadates and sulfates from the surface of the reaction solid, ensuring that vanadium and sulfur are not re-adsorbed by the petroleum coke powder. Furthermore, drying at 80°C to 90°C for 6 to 10 hours yields purified petroleum coke with low vanadium and sulfur content, ensuring the stability of the vanadium and sulfur removal rate. The washing can be done 3, 4, or 5 times.

[0057] The drying temperature can be 80℃, 81℃, 82℃, 83℃, 84℃, 85℃ or 90℃.

[0058] The drying time can be 6 hours, 7 hours, 8 hours, 9 hours, or 10 hours.

[0059] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0060] Example 1 like Figure 1 As shown, a method for removing vanadium and sulfur from petroleum coke, which contains vanadium and sulfur, includes: S1. The petroleum coke is crushed and sieved sequentially to obtain 30g of petroleum coke powder; S2. Oxidize the oxidant and petroleum coke powder to form soluble vanadium-containing salts and sulfur-containing salts with vanadium and sulfur, thus obtaining pretreated petroleum coke powder; S3. The alkaline solution and pretreated petroleum coke powder are subjected to a hydrothermal reaction to remove vanadium-containing salts and sulfur-containing salts, resulting in a reaction slurry; S4. Perform solid-liquid separation on the reaction slurry to obtain the reaction solid phase; S5. The reaction solids are washed and dried sequentially to obtain purified petroleum coke.

[0061] The volume V1 of the oxidant and the mass m1 of the petroleum coke powder satisfy the following: V1:m1=1:1. If the unit of V1 is L, then the unit of m1 is g.

[0062] The oxidizing agent is hydrogen peroxide.

[0063] The oxidation treatment time is 4 hours.

[0064] The molar concentration of the alkaline solution is 2 mol / L.

[0065] The alkaline solution is sodium hydroxide solution.

[0066] The volume V2 of the alkaline solution and the mass m2 of the pretreated petroleum coke powder satisfy the following ratio: V2:m2=1:1. If the unit of V2 is L, then the unit of m1 is g.

[0067] The hydrothermal reaction temperature was 90℃, and the hydrothermal reaction time was 60 min.

[0068] The particle size of petroleum coke powder is 250 mesh.

[0069] The washing was performed 4 times. The drying temperature is 85℃ and the drying time is 8 hours.

[0070] Example 2 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The volume V1 of the oxidant and the mass m1 of the petroleum coke powder satisfy the following ratio: V1:m1=2:1. If the unit of V1 is L, then the unit of m1 is g.

[0071] The oxidation treatment time is 5 hours.

[0072] The molar concentration of the alkaline solution is 3 mol / L.

[0073] The volume V2 of the alkaline solution and the mass m2 of the pretreated petroleum coke powder satisfy the following ratio: V2:m2 = 3:1. If the unit of V2 is L, then the unit of m1 is g.

[0074] The hydrothermal reaction temperature was 100℃, and the hydrothermal reaction time was 90 min.

[0075] The washing is performed 3 times.

[0076] Example 3 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The volume V1 of the oxidant and the mass m1 of the petroleum coke powder satisfy the following ratio: V1:m1 = 3:1. If the unit of V1 is L, then the unit of m1 is g.

[0077] The oxidation treatment time is 6 hours.

[0078] The molar concentration of the alkaline solution is 4 mol / L.

[0079] The volume V2 of the alkaline solution and the mass m2 of the pretreated petroleum coke powder satisfy the following ratio: V2:m2 = 4:1. If the unit of V2 is L, then the unit of m1 is g.

[0080] The hydrothermal reaction temperature was 110℃, and the hydrothermal reaction time was 120 min.

[0081] The washing process is repeated 5 times.

[0082] Example 4 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The volume V1 of the oxidant and the mass m1 of the petroleum coke powder satisfy the following ratio: V1:m1 = 3:1. If the unit of V1 is L, then the unit of m1 is g.

[0083] The oxidation treatment time is 6 hours.

[0084] The molar concentration of the alkaline solution is 5 mol / L.

[0085] The alkaline solutions are sodium hydroxide solution and / or potassium hydroxide solution.

[0086] The volume V2 of the alkaline solution and the mass m2 of the pretreated petroleum coke powder satisfy the following ratio: V2:m2=5:1. If the unit of V2 is L, then the unit of m1 is g.

[0087] The hydrothermal reaction temperature was 120℃, and the hydrothermal reaction time was 150 min.

[0088] Example 5 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The volume V1 of the oxidant and the mass m1 of the petroleum coke powder satisfy the following ratio: V1:m1 = 3:1. If the unit of V1 is L, then the unit of m1 is g.

[0089] The oxidation treatment time is 6 hours.

[0090] The molar concentration of the alkaline solution is 5 mol / L.

[0091] The volume V2 of the alkaline solution and the mass m2 of the pretreated petroleum coke powder satisfy the following ratio: V2:m2 = 7:1. If the unit of V2 is L, then the unit of m1 is g.

[0092] The hydrothermal reaction temperature was 130℃, and the hydrothermal reaction time was 180 min.

[0093] Comparative Example 1 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The volume V1 of the oxidant and the mass m1 of the petroleum coke powder satisfy the following: V1:m1=1:2. If the unit of V1 is L, then the unit of m1 is g.

[0094] The oxidation treatment time is 1.5 hours.

[0095] The molar concentration of the alkaline solution is 1 mol / L.

[0096] The volume V2 of the alkaline solution and the mass m2 of the pretreated petroleum coke powder satisfy the following ratio: V2:m2 = 1:2. If the unit of V2 is L, then the unit of m1 is g.

[0097] The hydrothermal reaction temperature was 70℃, and the hydrothermal reaction time was 40 min.

[0098] Comparative Example 2 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The volume V1 of the oxidant and the mass m1 of the petroleum coke powder satisfy the following ratio: V1:m1 = 5:1. If the unit of V1 is L, then the unit of m1 is g.

[0099] The oxidation treatment time is 8 hours.

[0100] The molar concentration of the alkaline solution is 6 mol / L.

[0101] The volume V2 of the alkaline solution and the mass m2 of the pretreated petroleum coke powder satisfy the following ratio: V2:m2=9:1. If the unit of V2 is L, then the unit of m1 is g.

[0102] The hydrothermal reaction temperature was 150℃, and the hydrothermal reaction time was 240 min.

[0103] Comparative Example 3 Compared to Example 1, the differences in this example are as follows, while the rest are the same: Without adding an oxidant, the petroleum coke powder is directly subjected to a hydrothermal reaction using an alkaline solution.

[0104] Comparative Example 4 Compared to Example 1, the differences in this example are as follows, while the rest are the same: Petroleum coke is oxidized directly using an oxidant without crushing or screening.

[0105] Comparative Example 5 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The hydrothermal reaction temperature was 70℃, and the hydrothermal reaction time was 40 min.

[0106] Comparative Example 6 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The hydrothermal reaction temperature was 150℃, and the hydrothermal reaction time was 240 min.

[0107] Relevant experimental and effect data: The purified petroleum coke obtained by the methods of each embodiment and comparative example was collected, and the removal rates of vanadium and sulfur were statistically analyzed. The results are shown in Table 1.

[0108] Table 1. Vanadium and sulfur removal rates of the methods in various embodiments and comparative examples.

[0109] As shown in Table 1, the method for removing vanadium and sulfur from petroleum coke provided in this application first converts insoluble vanadium and sulfur into soluble vanadates and sulfates through oxidation treatment. Then, a hydrothermal reaction is used to enhance the leaching efficiency of vanadium and sulfur from the petroleum coke. Finally, post-treatment processes such as solid-liquid separation, washing, and drying are used to avoid the residue of vanadates and sulfates, achieving a high removal rate of vanadium and sulfur from petroleum coke powder. Ultimately, purified petroleum coke with a vanadium removal rate of over 70% and a sulfur removal rate of over 50% can be obtained.

[0110] Compared to Example 1, Comparative Example 1 used insufficient oxidant and had inadequate oxidation time. This made it difficult to convert vanadium and sulfur in petroleum coke powder into soluble vanadates and sulfates, and high removal rates of vanadium and sulfur could not be achieved through hydrothermal reaction alone. Furthermore, Comparative Example 2 used a large amount of oxidant and a high-concentration alkaline solution, and employed a high hydrothermal reaction temperature and time. Although this resulted in a higher removal rate of vanadium and sulfur from the petroleum coke, the excessive use of oxidant and alkaline solution increased the cost of vanadium and sulfur removal from the petroleum coke.

[0111] Compared to Example 1, Comparative Example 3 did not use an oxidant, which made it difficult for the low-valence vanadium in the petroleum coke powder to form high-valence vanadium salts. Simultaneously, the organic sulfur in the petroleum coke powder was difficult to form soluble inorganic sulfur, resulting in extremely low removal rates of vanadium and sulfur from the petroleum coke powder. Comparative Example 4 did not involve crushing and sieving, making it difficult to obtain petroleum coke powder particles with high specific surface areas. During oxidation treatment or hydrothermal reaction, the oxidant or alkaline solution could not fully contact the vanadium and sulfur inside the petroleum coke, leading to a low removal rate of vanadium and sulfur from the petroleum coke.

[0112] Compared to Example 1, the temperature and time of the hydrothermal reaction in Comparative Example 5 were insufficient, making it difficult for the hydrothermal reaction to proceed fully, resulting in a low removal rate of vanadium and sulfur from petroleum coke. In Comparative Example 6, the temperature and time of the hydrothermal reaction were too high. Although this improved the removal rate of vanadium and sulfur from petroleum coke compared to Example 1, the overall energy consumption of the method increased significantly, raising the cost of removing vanadium and sulfur from petroleum coke.

[0113] In summary, the present application provides a method for removing vanadium and sulfur from petroleum coke. This method, through a complete process design of physical modification, chemical conversion, enhanced leaching, and refined post-treatment, specifically addresses the core bottlenecks of vanadium and sulfur in petroleum coke being difficult to dissolve, contact, and separate, ultimately achieving efficient removal of vanadium and sulfur from petroleum coke.

[0114] In addition, this application provides a method for removing vanadium and sulfur from petroleum coke. This method breaks down the insoluble barriers of vanadium and sulfur in petroleum coke through oxidation treatment, and then enhances the separation efficiency of vanadium and sulfur in petroleum coke through leaching with alkaline solution in hydrothermal reaction. The complete removal of vanadium and sulfur from petroleum coke is ensured through the synergistic effect of the entire process.

[0115] Furthermore, this application provides a method for removing vanadium and sulfur from petroleum coke. This method develops an efficient, environmentally friendly, and economically feasible low-temperature hydrothermal method. This low-temperature hydrothermal method is simple to operate and has a short process. It can effectively reduce the mass content of vanadium and sulfur in petroleum coke under relatively mild conditions, and has good economic benefits and great potential for industrial production. It provides a new technical path for the high-value utilization of degraded petroleum coke.

[0116] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for removing vanadium and sulfur from petroleum coke, characterized by, The petroleum coke contains vanadium and sulfur, and the method comprises: The petroleum coke is crushed and screened in sequence to obtain petroleum coke powder; An oxidizing agent and the petroleum coke powder are subjected to oxidation treatment so that the vanadium and the sulfur form soluble vanadium-containing salt and sulfur-containing salt to obtain pretreated petroleum coke powder; An alkaline solution and the pretreated petroleum coke powder are subjected to hydrothermal reaction to remove the vanadium-containing salt and the sulfur-containing salt to obtain a reaction slurry; The reaction slurry is subjected to solid-liquid separation to obtain a reaction solid phase; The reaction solid phase is subjected to washing and drying in sequence to obtain purified petroleum coke.

2. The method of claim 1, wherein, The volume V1 of the oxidizing agent and the mass m1 of the petroleum coke powder satisfy V1:m1=(1 to 3):1, wherein the unit of V1 is L and the unit of m1 is g.

3. The method of claim 1, wherein, The oxidizing agent is hydrogen peroxide and / or oxidized acetic acid.

4. The method of claim 1, wherein, The oxidation treatment is performed for 4 to 6 hours.

5. The method of claim 1, wherein, The alkaline solution has a molar concentration of 2 to 5 mol / L.

6. The method according to claim 1 or 5, characterized in that, The alkaline solution is sodium hydroxide solution and / or potassium hydroxide solution.

7. The method of claim 1, wherein, The volume V2 of the alkaline solution and the mass m2 of the pretreated petroleum coke powder satisfy V2:m2=(1 to 7):1, wherein the unit of V2 is L and the unit of m1 is g.

8. The method of claim 1, wherein, The hydrothermal reaction is performed at a temperature of 90 to 130 DEG C for 60 to 180 minutes.

9. The method of claim 1, wherein, The particle size of the petroleum coke powder is greater than or equal to 200 mesh.

10. The method of claim 1, wherein, The washing is performed for 3 to 5 times; and / or The drying is performed at a temperature of 80 to 90 DEG C for 6 to 10 hours.

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