A process for recycling dust collected from petroleum coke calcination

Abstract

The application discloses a petroleum coke calcination dust collection powder recycling process and belongs to the technical field of petroleum coke calcination. The process comprises pretreatment, mixing, compression molding, drying, sintering, crushing and recycling. In the pretreatment, petroleum coke calcination dust collection powder, sucrose and water are added into a mixing kettle and stirred to obtain a petroleum coke calcination dust collection powder mixture solution. Phenolic resin and anhydrous ethanol are added into the mixing kettle and stirred to obtain a phenolic resin solution. The petroleum coke calcination dust collection powder mixture solution and the phenolic resin solution are added into the mixing kettle and stirred, and then are transferred into a reaction kettle. After the reaction kettle is closed, the reaction kettle is kept at 180-190 DEG C for 8-10 h. The reaction kettle is opened, and the filter residue is filtered, cleaned and dried. The process can realize recycling of the petroleum coke calcination dust collection powder, and the mixing difficulty of the petroleum coke calcination dust collection powder and high-sulfur petroleum coke is small. The petroleum coke calcination dust collection powder is not easy to be pulverized during the crushing process after sintering, and the true density of the recycled product is not reduced.

Description

Technical Field

[0001] This invention relates to the field of petroleum coke calcination technology, specifically to a process for reusing dust collected during petroleum coke calcination. Background Technology

[0002] Petroleum coke calcination dust is a major byproduct generated during the calcination of petroleum coke in a pot furnace. This process involves calcining the petroleum coke at high temperatures to produce carbon products for various industrial applications. The dust collected from the calcined petroleum coke by a bag filter during this process is known as petroleum coke calcination dust. While the production volume of petroleum coke calcination dust is large, the particle size is small and the ash content is high, making it generally unsuitable for direct return to the system. Currently, the most common method is to sell it off-site at a low price, which not only wastes resources but also easily leads to leakage during loading, unloading, and transportation, causing secondary environmental pollution. Therefore, there is an urgent need for a method to reuse petroleum coke calcination dust and improve its economic value.

[0003] When reusing petroleum coke calcination dust, analysis of various performance indicators of the petroleum coke calcination dust revealed that the true density, particle size, moisture, volatile matter, sulfur content, ash content, and trace elements of the petroleum coke calcination dust are generally good. Furthermore, the petroleum coke calcination dust has the characteristics of low sulfur and high quality, and can be used as an additive for carbon products, or in the production of aluminum electrolyte anodes, graphite electrodes for steelmaking, carbon raisers, and other carbon products.

[0004] Furthermore, experiments have shown that, given the high calorific value and low ash content of high-sulfur petroleum coke, mixing it with low-calorific-value, high-ash petroleum coke calcination dust powder and using it as a recycled material in the calcination workshop can achieve the goal of reusing petroleum coke calcination dust powder. This can also effectively solve a series of technical problems such as environmental pollution, resource waste, increased energy consumption, low economic benefits, and secondary pollution. Moreover, the operation is simple and can further improve the utilization rate and economic value of petroleum coke calcination dust powder, which is of great significance for promoting sustainable development.

[0005] The most common method for reusing high-sulfur petroleum coke by mixing it with calcined petroleum coke dust is to mix the dust with high-sulfur petroleum coke and a binder, add water, press the mixture into shape, and then sinter and crush it. While this method is simple, it has the following problems: The calcined petroleum coke dust has a smaller particle size than high-sulfur petroleum coke, making mixing difficult and time-consuming. To avoid the inconvenience caused by the small particle size of the calcined petroleum coke dust, a binder needs to be added during the mixing process, followed by pressing and shaping. The binder plays a role in binding the petroleum coke calcined dust and high-sulfur petroleum coke during compression molding, followed by sintering and pulverization. However, the binder undergoes thermal decomposition after sintering, leading to a decrease in the hardness of the sintered body. This makes the sintered body prone to pulverization during subsequent crushing, affecting the quality and recycling efficiency of the reused product. The true density of the petroleum coke calcined dust is relatively low. When high-sulfur petroleum coke is mixed with the petroleum coke calcined dust, the addition of the petroleum coke calcined dust will cause an overall decrease in the true density of the reused product. This decrease in true density may affect the physical and chemical properties of the product, thereby impacting its effectiveness in practical applications. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention improves mixing equipment and processes to enhance mixing efficiency and uniformity while reducing mixing time. It also adjusts the binder formulation and addition method to minimize the impact of binder thermal decomposition on the hardness of the sintered body during sintering. Furthermore, it appropriately adjusts the ratio of high-sulfur petroleum coke to calcined petroleum coke dust powder according to actual needs and product requirements, balancing the true density and other performance indicators of the product. Specifically, this invention provides a process for reusing calcined petroleum coke dust powder, enabling its reuse. The process is less difficult to mix with high-sulfur petroleum coke, is less prone to pulverization during post-sintering crushing, and does not lead to a decrease in the true density of the reused product.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A process for reusing dust collected from calcined petroleum coke includes: pretreatment, mixing, pressing, drying, sintering, crushing, and reuse.

[0009] The pretreatment involves adding petroleum coke calcined dust, sucrose, and water to a mixing vessel, controlling the mixing speed at 200-400 rpm, and stirring for 20-30 minutes to obtain a petroleum coke calcined dust mixture. Then, phenolic resin and anhydrous ethanol are added to the mixing vessel, controlling the mixing speed at 200-400 rpm, and stirring for 40-60 minutes to obtain a phenolic resin solution. The petroleum coke calcined dust mixture and the phenolic resin solution are added to the mixing vessel, controlling the mixing speed at 200-400 rpm, and stirring for 40-60 minutes. The mixture is then transferred to a reaction vessel, sealed, and the temperature is controlled at 180-190℃. This temperature is maintained for 8-10 hours. The reaction vessel is then opened, filtered, and the filter residue is washed 3-4 times with deionized water and 3-4 times with anhydrous ethanol. The residue is then dried at 110-130℃ to constant weight to obtain the pretreated petroleum coke calcined dust.

[0010] In the pretreatment, the mass ratio of petroleum coke calcination dust, sucrose, water, phenolic resin, and anhydrous ethanol is 20-23:0.9-1:90-120:0.8-1.1:8-8.5.

[0011] The petroleum coke calcination dust has a sulfur content of 2.28%, an ash content of 0.68%, and a true density of 2.04 g / cm³. 3 ;

[0012] The phenolic resin is a linear phenolic resin with a molecular weight of 2000;

[0013] The mixing process involves adding pretreated petroleum coke calcination dust, high-sulfur petroleum coke powder, pregelatinized starch, and nano-graphite into a mixing vessel. The speed of the mixing vessel is controlled at 200-400 rpm. After the mixture is homogeneous, water is added, and stirring is continued for 50-60 minutes to obtain the mixture.

[0014] In the mixture, the mass ratio of pretreated petroleum coke calcination dust, high-sulfur petroleum coke powder, pregelatinized starch, nano-graphite, and water is 20:20-30:0.4-0.5:0.2-0.22:20-23.

[0015] The high-sulfur petroleum coke powder has a sulfur content of 5% and an ash content of 0.23%.

[0016] The particle size of the nanographite is 80-100 nm;

[0017] The pressing process involves adding the mixture into a mold and pressing it. The pressure during pressing is controlled at 12-15 MPa, and the time is 2-2.5 hours. After pressing, a blank is obtained.

[0018] The drying process involves placing the green body into an oven for drying, controlling the drying temperature at 140-160℃ for 5.5-6.5 hours to obtain the dried green body.

[0019] The sintering process involves adding the dried green body into a pot furnace for calcination, controlling the calcination temperature at 1200-1300℃ and the time at 50-60h to obtain a sintered body.

[0020] The crushing process involves adding the sintered body to a double-toothed roller crusher for crushing, controlling the crushing speed at 100-150 rpm to obtain coarse particles with a diameter of less than 50 mm. Then, the coarse particles are transferred to a hammer crusher for fine crushing, controlling the fine crushing speed at 1000-1100 rpm to obtain mixed particles of petroleum coke calcination dust powder with a diameter of less than 3 mm.

[0021] The aforementioned reuse involves using the mixed particles of petroleum coke calcination dust as a recycled material in the calcination workshop.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) The petroleum coke calcination dust collection powder reuse process of the present invention is to mix low sulfur and high ash petroleum coke calcination dust collection powder with high sulfur and low ash high sulfur petroleum coke powder, press it into shape, dry it, sinter it and granulate it. The mixed particles are then used as a re-admixture in the calcination workshop, which can realize the reuse of petroleum coke calcination dust collection powder and is simple to operate.

[0024] (2) The petroleum coke calcination dust collection powder reuse process of the present invention pre-treats the petroleum coke calcination dust collection powder and then mixes it with high sulfur petroleum coke, and adds nano-graphite in the mixing process, which can reduce the mixing difficulty.

[0025] (3) The petroleum coke calcination dust collection powder reuse process of the present invention, after pre-treating the petroleum coke calcination dust collection powder, mixes it with high sulfur petroleum coke, which can avoid the pulverization problem that exists in the crushing of sintered body.

[0026] (4) The petroleum coke calcination dust collection powder reuse process of the present invention involves pretreating the petroleum coke calcination dust collection powder before mixing it with high-sulfur petroleum coke, and adding nano-graphite to the mixture, which can improve the true density of the reused product. The true density of the petroleum coke calcination dust collection powder mixture particles obtained by the present invention is 2.09-2.10 g / cm³. 3 . Detailed Implementation

[0027] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention are now described.

[0028] Example 1

[0029] A process for reusing dust collected from calcined petroleum coke, specifically:

[0030] 1. Pretreatment: Add 20 kg of petroleum coke calcination dust, 0.9 kg of sucrose, and 90 kg of water to a mixing vessel. Control the mixing speed of the vessel to 200 rpm and stir for 20 min to obtain a petroleum coke calcination dust mixture. Add 0.8 kg of phenolic resin and 8 kg of anhydrous ethanol to the mixing vessel. Control the mixing speed of the vessel to 200 rpm and stir for 40 min to obtain a phenolic resin solution. Add the petroleum coke calcination dust mixture and the phenolic resin solution to the mixing vessel. Control the mixing speed of the vessel to 200 rpm and stir for 40 min. Transfer the mixture to a reaction vessel. After sealing the reaction vessel, control the temperature of the reaction vessel to 180℃ and maintain it at 180℃ for 8 h. Open the reaction vessel, filter, wash the filter residue three times with deionized water, wash the filter residue three times with anhydrous ethanol, and dry at 110℃ to constant weight to obtain the pretreated petroleum coke calcination dust.

[0031] The petroleum coke calcination dust has a sulfur content of 2.28%, an ash content of 0.68%, and a true density of 2.04 g / cm³. 3 ;

[0032] The phenolic resin is a linear phenolic resin with a molecular weight of 2000;

[0033] 2. Mixing: Add 20kg of pretreated petroleum coke calcination dust, 20kg of high-sulfur petroleum coke powder, 0.4kg of pregelatinized starch, and 0.2kg of nano-graphite to a mixing vessel. Control the speed of the mixing vessel to 200rpm. After mixing evenly, add 20kg of water and continue stirring for 50min to obtain the mixture.

[0034] The high-sulfur petroleum coke powder has a sulfur content of 5% and an ash content of 0.23%.

[0035] The particle size of the nanographite is 80 nm;

[0036] 3. Press molding: Add the mixture to the mold and press it into shape. Control the pressure during pressing and molding at 12MPa for 2 hours. After pressing and molding, the blank is obtained.

[0037] 4. Drying: Place the green body into an oven for drying, control the drying temperature at 140℃ for 5.5 hours, and obtain the dried green body;

[0038] 5. Sintering: The dried green body is added to a pot furnace for calcination. The calcination temperature is controlled at 1200℃ and the time is 50h to obtain the sintered body.

[0039] 6. Crushing: The sintered body is added to a double-toothed roller crusher for crushing. The crushing speed is controlled at 100 rpm to obtain coarse particles with a diameter of less than 50 mm. Then, the coarse particles are transferred to a hammer crusher for fine crushing. The crushing speed is controlled at 1000 rpm to obtain mixed particles of petroleum coke calcination dust powder with a diameter of less than 3 mm.

[0040] 7. Reuse: The mixed granules of petroleum coke calcination dust collection powder are used as recycled material in the calcination workshop.

[0041] Example 2

[0042] A process for reusing dust collected from calcined petroleum coke, specifically:

[0043] 1. Pretreatment: 22 kg of petroleum coke calcination dust, 0.9 kg of sucrose, and 100 kg of water were added to a mixing vessel. The mixing vessel was stirred at 300 rpm for 25 min to obtain a petroleum coke calcination dust mixture. 0.9 kg of phenolic resin and 8.2 kg of anhydrous ethanol were added to the mixing vessel. The mixing vessel was stirred at 300 rpm for 50 min to obtain a phenolic resin solution. The petroleum coke calcination dust mixture and the phenolic resin solution were added to the mixing vessel. The mixing vessel was stirred at 300 rpm for 50 min. The mixture was then transferred to a reaction vessel. The reaction vessel was sealed, and the temperature of the reaction vessel was controlled at 185℃. The mixture was kept at 185℃ for 9 h. The reaction vessel was then opened, and the mixture was filtered. The filter residue was washed three times with deionized water and three times with anhydrous ethanol. The mixture was dried at 120℃ to constant weight to obtain the pretreated petroleum coke calcination dust.

[0044] The petroleum coke calcination dust has a sulfur content of 2.28%, an ash content of 0.68%, and a true density of 2.04 g / cm³. 3 ;

[0045] The phenolic resin is a linear phenolic resin with a molecular weight of 2000;

[0046] 2. Mixing: Add 20kg of pretreated petroleum coke calcination dust, 25kg of high-sulfur petroleum coke powder, 0.45kg of pregelatinized starch, and 0.21kg of nano-graphite to a mixing vessel. Control the speed of the mixing vessel to 300rpm. After mixing evenly, add 22kg of water and continue stirring for 55min to obtain the mixture.

[0047] The high-sulfur petroleum coke powder has a sulfur content of 5% and an ash content of 0.23%.

[0048] The nano-graphite has a particle size of 100 nm;

[0049] 3. Press molding: The mixture is added to the mold and pressed. The pressure during pressing is controlled at 14MPa and the time is 2.2h. After pressing, the blank is obtained.

[0050] 4. Drying: Place the green body into an oven for drying, control the drying temperature at 150℃ for 6 hours, and obtain the dried green body;

[0051] 5. Sintering: The dried green body is added to a pot furnace for calcination. The calcination temperature is controlled at 1250℃ and the time is 55h to obtain the sintered body.

[0052] 6. Crushing: The sintered body is added to a double-toothed roller crusher for crushing. The crushing speed is controlled at 120 rpm to obtain coarse particles with a diameter of less than 50 mm. Then the coarse particles are transferred to a hammer crusher for fine crushing. The crushing speed is controlled at 1050 rpm to obtain mixed particles of petroleum coke calcination dust collection powder with a diameter of less than 3 mm.

[0053] 7. Reuse: The mixed granules of petroleum coke calcination dust collection powder are used as recycled material in the calcination workshop.

[0054] Example 3

[0055] A process for reusing dust collected from calcined petroleum coke, specifically:

[0056] 1. Pretreatment: 23 kg of petroleum coke calcination dust, 1 kg of sucrose, and 120 kg of water were added to a mixing vessel. The mixing vessel was stirred at 400 rpm for 30 min to obtain a petroleum coke calcination dust mixture. 1.1 kg of phenolic resin and 8.5 kg of anhydrous ethanol were added to a mixing vessel. The mixing vessel was stirred at 400 rpm for 60 min to obtain a phenolic resin solution. The petroleum coke calcination dust mixture and the phenolic resin solution were added to a mixing vessel. The mixing vessel was stirred at 400 rpm for 60 min. The mixture was then transferred to a reaction vessel. The reaction vessel was sealed, and the temperature was controlled at 190℃. The mixture was kept at 190℃ for 10 h. The reaction vessel was then opened, filtered, and the filter residue was washed 4 times with deionized water and 4 times with anhydrous ethanol. The residue was dried at 130℃ to constant weight to obtain the pretreated petroleum coke calcination dust.

[0057] The petroleum coke calcination dust has a sulfur content of 2.28%, an ash content of 0.68%, and a true density of 2.04 g / cm³. 3 ;

[0058] The phenolic resin is a linear phenolic resin with a molecular weight of 2000;

[0059] 2. Mixing: Add 20kg of pretreated petroleum coke calcination dust, 30kg of high-sulfur petroleum coke powder, 0.5kg of pregelatinized starch, and 0.22kg of nano-graphite to a mixing vessel. Control the speed of the mixing vessel to 400rpm. After mixing evenly, add 23kg of water and continue stirring for 60min to obtain the mixture.

[0060] The high-sulfur petroleum coke powder has a sulfur content of 5% and an ash content of 0.23%.

[0061] The nano-graphite has a particle size of 100 nm;

[0062] 3. Press molding: The mixture is added to the mold and pressed. The pressure during pressing is controlled at 15MPa and the time is 2.5h. After pressing, the blank is obtained.

[0063] 4. Drying: Place the green body into an oven for drying, controlling the drying temperature at 160℃ for 6.5 hours to obtain the dried green body;

[0064] 5. Sintering: The dried green body is added to a pot furnace for calcination. The calcination temperature is controlled at 1300℃ and the time is 60h to obtain the sintered body.

[0065] 6. Crushing: The sintered body is added to a double-toothed roller crusher for crushing. The crushing speed is controlled at 150 rpm to obtain coarse particles with a diameter of less than 50 mm. Then, the coarse particles are transferred to a hammer crusher for fine crushing. The crushing speed is controlled at 1100 rpm to obtain mixed particles of petroleum coke calcination dust collection powder with a diameter of less than 3 mm.

[0066] 7. Reuse: The mixed granules of petroleum coke calcination dust collection powder are used as recycled material in the calcination workshop.

[0067] Comparative Example 1

[0068] This comparative example is an adjustment to the process of Example 2. The specific adjustments are: the first step of pretreatment is omitted, and in the second step of mixing, an equal amount of petroleum coke calcination dust powder is used to replace the pretreated petroleum coke calcination dust powder.

[0069] Comparative Example 2

[0070] This comparative example is an adjustment to the process of Example 2. Specifically, the addition of nano-graphite was omitted in the mixing step 2.

[0071] Experimental Example 1

[0072] In the second step of the mixing process of Examples 1-3 and Comparative Examples 1-2, the time required from the start of stirring to uniform mixing after adding the pretreated petroleum coke calcination dust, high-sulfur petroleum coke powder, pregelatinized starch, and nano-graphite to the mixing vessel was recorded. The results are as follows:

[0073]

[0074] Experimental Example 2

[0075] In step 6 of the crushing process in Examples 1-3 and Comparative Examples 1-2, it was observed whether pulverization occurred when using a double-toothed roll crusher for crushing and when using a hammer crusher for fine crushing. The results are as follows:

[0076]

[0077] Experimental Example 3

[0078] The true density of the mixed particles of petroleum coke calcination dust obtained in Examples 1-3 and Comparative Examples 1-2 was tested, and the results are as follows:

[0079]

[0080] The results of Experiments 1-3 show that pretreatment of petroleum coke calcination dust can shorten the mixing time required for mixing petroleum coke calcination dust with high-sulfur petroleum coke calcination dust, avoid pulverization problems during crushing, and improve the true density of the resulting petroleum coke calcination dust mixture particles. Furthermore, adding nano-graphite to the mixture can shorten the mixing time required for mixing petroleum coke calcination dust with high-sulfur petroleum coke calcination dust and improve the true density of the resulting petroleum coke calcination dust mixture particles.

[0081] Pretreatment of petroleum coke calcination dust involves mixing petroleum coke calcination dust, sucrose, phenolic resin, water, and anhydrous ethanol, followed by solvothermal treatment. During solvothermal treatment, sucrose and phenolic resin cross-link on the surface of the petroleum coke calcination dust, resulting in a layer of cross-linked sucrose and phenolic resin coating. Firstly, the presence of this cross-linked coating increases the particle size of the petroleum coke calcination dust, thereby reducing the particle size difference between the petroleum coke calcination dust and high-sulfur petroleum coke powder. Secondly, the presence of this cross-linked coating can... The cross-linked material acts as an adhesive, binding the calcined petroleum coke dust powder and high-sulfur petroleum coke powder together during the pressing process. Thirdly, the cross-linked material coating the surface of the calcined petroleum coke dust powder effectively fixes it, preventing pulverization during crushing. Fourthly, compared to adding the adhesive directly to the mixture, the cross-linked material has a higher density, forming high-density cross-linked carbon after carbonization, which is more conducive to improving the true density of the mixed particles of calcined petroleum coke dust powder.

[0082] Adding nano-graphite to the mixture serves two purposes: firstly, it acts as a lubricant, thus promoting mixing; secondly, it fills the voids in the mixed particles of petroleum coke calcination dust and promotes the bonding between raw materials, thereby increasing the true density of the mixed particles of petroleum coke calcination dust.

[0083] Unless otherwise stated, all percentages used in this invention are mass percentages.

[0084] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for reusing the dust collected during the calcination of petroleum coke, characterized in that, It comprises: pretreatment, mixing, compression molding, drying, sintering, crushing, recycling; the pretreatment, the calcined dust powder of petroleum coke, sucrose, water are added into a mixing kettle, stirred, and the calcined dust powder of petroleum coke is obtained; phenolic resin, anhydrous ethanol are added into the mixing kettle, stirred, and the phenolic resin solution is obtained; the calcined dust powder of petroleum coke and the phenolic resin solution are added into the mixing kettle, stirred, and transferred into the reaction kettle; after the reaction kettle is closed, the temperature of the reaction kettle is controlled to 180-190 DEG C, and kept for 8-10 h at 180-190 DEG C; the reaction kettle is opened, filtered, washed, and dried, and the pretreated calcined dust powder of petroleum coke is obtained; the mixing, the pretreated calcined dust powder of petroleum coke, high-sulfur petroleum coke powder, pre-gelatinized starch, nano-graphite and water are added into a mixing kettle, stirred, and the mixture is obtained; in the mixing, the mass ratio of the pretreated calcined dust powder of petroleum coke, high-sulfur petroleum coke powder, pre-gelatinized starch, nano-graphite and water is 20:20-30:0.4-0.5:0.2-0.22:20-23; the particle size of the nano-graphite is 80-100 nm.

2. The process for reusing the dust collected during the calcination of petroleum coke according to claim 1, characterized in that, in the pretreatment, the mass ratio of the calcined dust powder of petroleum coke, sucrose, water, phenolic resin and anhydrous ethanol is 20-23:0.9-1:90-120:0.8-1.1:8-8.5; the phenolic resin is linear phenolic resin, and the molecular weight is 2000.

3. The process for reusing the dust collected during the calcination of petroleum coke according to claim 1, characterized in that, the compression molding, the mixture is added into a mold for compression molding, and the compression molding is completed to obtain a green body; in the compression molding, the pressure during compression molding is 12-15 MPa, and the time is 2-2.5 h.

4. The process for reusing the dust collected during the calcination of petroleum coke according to claim 3, characterized in that, the drying, the green body is added into an oven for drying to obtain a dried green body; in the drying, the temperature during drying is 140-160 DEG C, and the time is 5.5-6.5 h.

5. The process for reusing the dust collected during the petroleum coke calcination according to claim 4, characterized in that, the sintering, the dried green body is added into a tank furnace for calcination to obtain a sintered body; in the sintering, the temperature during calcination is 1200-1300 DEG C, and the time is 50-60 h.

6. The process for reusing the dust collected during the calcination of petroleum coke according to claim 5, characterized in that, the crushing, the sintered body is added into a double-toothed roll crusher for crushing to obtain coarse particles with a diameter of less than 50 mm, and then the coarse particles are transferred into a hammer crusher for fine crushing to obtain petroleum coke calcined dust powder mixed particles with a diameter of less than 3 mm.

7. The process as claimed in claim 1, wherein the said process is characterized by, the recycling, the petroleum coke calcined dust powder mixed particles are used as calcination workshop back-doping materials.

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