A petroleum coke calcining process

Abstract

The present application discloses a calcination process for petroleum coke, which relates to the technical field of carbon product preparation, comprising the following steps: S1. After the petroleum coke is crushed, red mud microspheres are added for mixed ball milling, dried and sieved to obtain pretreated petroleum coke; S2. A porous cerium-doped nano-iron oxide desulfurizer is added to the pretreated petroleum coke, and the mixture is evenly mixed to obtain a mixture to be calcined; S3. The mixture to be calcined is transferred to a tubular furnace, heated under a nitrogen atmosphere, and after heating to 750-850°C, kept warm for 1-2 hours to obtain desulfurized petroleum coke; taken out after natural cooling, washed with hydrochloric acid solution, and then washed with deionized water until the mixture is neutral, filtered and dried; S4. The dried desulfurized petroleum coke is calcined at 900-1200°C for 3-5 hours to obtain calcined petroleum coke. The calcination process provided by the present application can effectively improve the desulfurization rate of petroleum coke, and obtain calcined petroleum coke with low ash, low sulfur and high density.

Description

Technical Field

[0001] The present application relates to the field of carbon product preparation technology, and in particular to a petroleum coke calcination process. Background Art

[0002] Petroleum coke is an important industrial intermediate, produced during the delayed coking process to produce light oil. It can be used in the metallurgical and chemical industries as a raw material for electrodes and chemical products. Petroleum coke, used in the production of graphite electrodes for steelmaking and anodes for aluminum smelting, requires calcination to meet production requirements. This calcination removes volatiles, moisture, and some sulfur from the petroleum coke, while increasing its density and strength, and improving its electrical conductivity and antioxidant properties.

[0003] During the calcination process, certain impurities in the petroleum coke are gradually expelled due to heat. During the low-temperature stage, adsorbed gases (O2, N2, CO2, CO, etc.) are expelled. At temperatures around 450°C, elemental sulfur vaporizes and is expelled. When the temperature reaches above 1200°C, some organic sulfur is also expelled. This sulfur expulsion results in large amounts of SO2 in the calcination flue gas. SO2 is a major atmospheric pollutant. Large amounts of SO2 emissions can cause pollution such as acid rain and photochemical smog, harming human health and disrupting ecological balance. Therefore, flue gas with excessive SO2 levels must undergo desulfurization treatment.

[0004] However, most effective industrial desulfurization methods for petroleum coke rely on high-temperature desulfurization. The petroleum coke is first heated to 600-1200°C, then transferred to an electric furnace and heated further to 1700-2300°C to remove sulfur and other impurities, resulting in a petroleum coke sulfur content of less than 0.1%. However, desulfurization solely through heating is inefficient and energy-intensive, making it unsuitable for large-scale desulfurization. Summary of the Invention

[0005] In order to provide a petroleum coke calcining method with high desulfurization efficiency and low energy consumption, the present application provides a petroleum coke calcining process method.

[0006] The present application provides a petroleum coke calcination process method, which adopts the following technical solution:

[0007] A petroleum coke calcining process comprises the following steps:

[0008] S1. After the petroleum coke was crushed, red mud microspheres were added and mixed and ball-milled, dried and sieved to obtain pretreated petroleum coke;

[0009] S2. A porous cerium-doped nano-iron oxide desulfurizer was added to the pretreated petroleum coke and mixed to obtain a mixture to be calcined;

[0010] S3. The mixture to be calcined was transferred to a tube furnace and heated under a nitrogen atmosphere to 750-850 ° C and kept for 1-2h to obtain desulfurized petroleum coke; after cooling naturally, the mixture was removed, washed with hydrochloric acid solution, and then washed with deionized water until the mixture was neutral, filtered, and dried;

[0011] S4. The dried desulfurized petroleum coke is calcined at 900-1200° C. for 3-5 hours to obtain calcined petroleum coke.

[0012] Preferably, the method for preparing red mud microspheres comprises the following steps:

[0013] The red mud is dried at 105-120°C for 24-36 hours, plant fibers are added and mixed evenly, and then ground. After drying, the mixture is passed through a 100-300 μm sieve to obtain red mud microspheres.

[0014] Preferably, the mass ratio of the red mud to the plant fiber is 1:0.002-0.006.

[0015] Preferably, the mass ratio of the petroleum coke to the red mud microspheres is 1:0.01-0.05.

[0016] Preferably, the porous cerium-doped nano-iron oxide desulfurizer is made from the following raw materials in parts by weight: 2-3 parts of cerium nitrate hexahydrate, 4-6 parts of iron nitrate hexahydrate, 200-400 parts of deionized water, 0.12-0.18 parts of plant fiber, and 3.5-7 parts of precipitant.

[0017] Preferably, the precipitant is ammonium carbonate.

[0018] Preferably, the plant fiber is a mixture of one or more of loofah fiber, jute fiber, straw fiber and bamboo fiber.

[0019] Preferably, the preparation method of the porous cerium-doped nano-iron oxide desulfurizer comprises the following steps:

[0020] pre-treating the plant fibers;

[0021] Cerium nitrate hexahydrate and iron nitrate hexahydrate are added to deionized water, stirred evenly, and then pretreated plant fibers are added and ultrasonically dispersed evenly; then a precipitant is added under stirring conditions of 80-90°C, stirred continuously for 2-4 hours, and then cooled to room temperature, filtered, washed several times, and then dried in an oven at 105-115°C for 4-6 hours, and then calcined at 450-550°C for 3-4 hours to obtain a porous cerium-doped nano-iron oxide desulfurizer.

[0022] Preferably, the plant fiber pretreatment method comprises the following steps:

[0023] The plant fiber is dried and placed in a muffle furnace for pre-oxidation at 200-300° C. for 2-3 hours. After cooling to room temperature, the plant fiber is immersed in water for 20-30 hours and then dried to obtain the pretreated plant fiber.

[0024] Preferably, the mass ratio of the petroleum coke to the porous cerium-doped nano-iron oxide desulfurizer is 1:0.06-0.1.

[0025] In summary, this application includes at least one of the following beneficial technical effects:

[0026] 1. By adopting the above technical solution, the present application uses red mud microspheres and petroleum coke for ball milling treatment, which can fully expose the sulfide. By adjusting the structure of the petroleum coke, the internal graphite microcrystalline structure of the petroleum coke is loosened, and the contact area between the sulfide and the desulfurizer is increased, which is conducive to subsequent desulfurization treatment and enhances the desulfurization efficiency. The addition of red mud microspheres can also fill the gaps between the petroleum coke particles, reduce the porosity, make the material denser, and improve the mechanical strength and thermal stability of the material. During the mixed ball milling process, the morphology of the composite material formed is more uniform. Red mud also has a good removal effect on sulfur dioxide. The present application modifies red mud with plant fibers, which not only improves the mechanical strength and thermal stability of red mud, but also enhances the adsorption capacity of red mud for sulfur dioxide.

[0027] 2. This application uses ammonium carbonate as a precipitant and a co-precipitation method with plant fibers as carriers to prepare a cerium-doped iron oxide nano-adsorption desulfurizer. By pre-oxidizing the plant fibers, the surface area and pore structure of the fibers can be increased, further improving the desulfurization efficiency of the desulfurizer.

[0028] 3. The petroleum coke calcining process provided in this application produces calcined petroleum coke with a high density, good product stability, uniform quality, low ash and low sulfur, and a wide range of applications. DETAILED DESCRIPTION

[0029] The present application is further described in detail below with reference to the embodiments.

[0030] Preparation Example

[0031] Preparation Example 1 Preparation of red mud microspheres

[0032] Preparation Example 1.1

[0033] 100 g of red mud was dried at 105° C. for 36 h, 0.2 g of loofah fiber was added, mixed evenly, and then ground. After drying, the mixture was passed through a 100 μm sieve to obtain red mud microspheres.

[0034] Preparation Example 1.2

[0035] 100 g of red mud was dried at 115° C. for 30 h, 0.4 g of loofah fiber was added, mixed evenly, and ground. After drying, the mixture was passed through a 200 μm sieve to obtain red mud microspheres.

[0036] Preparation Example 1.3

[0037] 100 g of red mud was dried at 120° C. for 24 h, 0.6 g of loofah fiber was added, mixed evenly, and ground. After drying, the mixture was passed through a 300 μm sieve to obtain red mud microspheres.

[0038] Preparation Example 1.4

[0039] The difference between Preparation Example 1.4 and Preparation Example 1.1 is that the plant fiber used in Preparation Example 1.4 is straw fiber.

[0040] Preparation Example 1.5

[0041] The difference between Preparation Example 1.5 and Preparation Example 1.1 is that the plant fiber used in Preparation Example 1.5 is a composite of jute fiber and bamboo fiber, with a mass ratio of 1:1.

[0042] Preparation Example 2 Preparation of Porous Cerium-doped Nano-iron Oxide Desulfurizer

[0043] Preparation Example 2.1

[0044] S1. 0.12g of loofah fiber was dried and placed in a muffle furnace, pre-oxidized at 200 ° C for 3h, cooled to room temperature, immersed in water, allowed to stand for 20h, and dried to obtain pretreated loofah fiber;

[0045] S2. Add 2g of cerium nitrate hexahydrate and 4g of iron nitrate hexahydrate to 200g of deionized water, stir evenly, add pretreated loofah fiber, and ultrasonically disperse evenly at 200W for 1h; then add 3.5g of ammonium carbonate under stirring conditions at 80°C, stir continuously for 2h, then cool to room temperature and filter, wash three times with deionized water, then dry in an oven at 105°C for 6h, and then calcine at 450°C for 4h to obtain a porous cerium-doped nano-iron oxide desulfurizer.

[0046] Preparation Example 2.2

[0047] S1. 0.15g of loofah fiber was dried and placed in a muffle furnace, pre-oxidized at 250 ° C for 2.5h, cooled to room temperature, immersed in water, allowed to stand for 25h, and dried to obtain pretreated loofah fiber;

[0048] S2. Add 2.5g of cerium nitrate hexahydrate and 5g of iron nitrate hexahydrate to 250g of deionized water, stir evenly, add pretreated loofah fiber, and ultrasonically disperse evenly at 250W for 1.5h; then add 5.3g of ammonium carbonate under stirring conditions at 85°C, stir continuously for 3h, then cool to room temperature and filter, wash three times with deionized water, then dry in an oven at 110°C for 5h, and then calcine at 500°C for 3.5h to obtain a porous cerium-doped nano-iron oxide desulfurizer.

[0049] Preparation Example 2.3

[0050] S1. 0.18g of loofah fiber was dried and placed in a muffle furnace, pre-oxidized at 300 ° C for 2h, cooled to room temperature, immersed in water, allowed to stand for 30h, and dried to obtain pretreated loofah fiber;

[0051] S2. Add 3g of cerium nitrate hexahydrate and 6g of iron nitrate hexahydrate to 300g of deionized water, stir evenly, add pretreated loofah fiber, and ultrasonically disperse evenly at 300W for 2h; then add 7g of ammonium carbonate under stirring conditions at 90°C, stir continuously for 4h, then cool to room temperature and filter, wash three times with deionized water, then dry in an oven at 115°C for 4h, and then calcine at 550°C for 3h to obtain a porous cerium-doped nano-iron oxide desulfurizer.

[0052] Preparation Example 2.4

[0053] The difference between Preparation Example 2.4 and Preparation Example 2.1 is that the plant fiber used in Preparation Example 2.4 is straw fiber.

[0054] Preparation Example 2.5

[0055] The difference between Preparation Example 2.5 and Preparation Example 2.1 is that the plant fiber used in Preparation Example 2.5 is a composite of jute fiber and bamboo fiber, with a mass ratio of 1:1. Example Example 1

[0056] S1. After 1000g of petroleum coke was crushed, 10g of red mud microspheres prepared in Preparation Example 1.1 were added and mixed and ball-milled, and then dried and sieved through a 200-micron sieve to obtain pretreated petroleum coke;

[0057] S2 was added to the pretreated petroleum coke 60g prepared by the porous cerium-doped nano-iron oxide desulfurizer in Preparation Example 2.1, mixed to obtain a mixture to be calcined;

[0058] S3. The mixture to be calcined was transferred to a tube furnace and heated under a nitrogen atmosphere to 750 ° C and kept for 2 hours to obtain desulfurized petroleum coke; after natural cooling, the mixture was removed and washed with 5% hydrochloric acid solution by mass, and then washed with deionized water until the mixture was neutral, filtered, and dried;

[0059] S4. The dried desulfurized petroleum coke is calcined at 900° C. for 5 h to obtain calcined petroleum coke. Example 2

[0060] S1. After 1000g of petroleum coke was crushed, 10g of red mud microspheres prepared in Preparation Example 1.1 were added and mixed and ball-milled, and then dried and passed through a 150-micron sieve to obtain pretreated petroleum coke;

[0061] S2 was added to the pretreated petroleum coke 60g prepared by the porous cerium-doped nano-iron oxide desulfurizer in Preparation Example 2.1, mixed to obtain a mixture to be calcined;

[0062] S3. The mixture to be calcined was transferred to a tube furnace and heated under a nitrogen atmosphere to 800 ° C and kept warm for 1.5h to obtain desulfurized petroleum coke; after natural cooling, the mixture was removed and washed with 5% hydrochloric acid solution by mass, and then washed with deionized water until the mixture was neutral, filtered, and dried;

[0063] S4. The dried desulfurized petroleum coke is calcined at 1100° C. for 4 h to obtain calcined petroleum coke. Example 3

[0064] S1. After 1000g of petroleum coke was crushed, 10g of red mud microspheres prepared in Preparation Example 1.1 were added and mixed and ball-milled, and then dried and sieved through a 100-micron sieve to obtain pretreated petroleum coke;

[0065] S2 was added to the pretreated petroleum coke 60g prepared by the porous cerium-doped nano-iron oxide desulfurizer in Preparation Example 2.1, mixed to obtain a mixture to be calcined;

[0066] S3. The mixture to be calcined was transferred to a tube furnace and heated under a nitrogen atmosphere to 850°C and held for 1 hour to obtain desulfurized petroleum coke; the mixture was removed after natural cooling, washed with a 5% hydrochloric acid solution by mass, and then washed with deionized water until the mixture was neutral, filtered, and dried;

[0067] S4. The dried desulfurized petroleum coke is calcined at 1200° C. for 3 h to obtain calcined petroleum coke. Example 4

[0068] The difference between Example 4 and Example 1 is that the red mud microspheres used in Example 4 are from Preparation Example 1.1, and the added amount is 30 g. Example 5

[0069] The difference between Example 5 and Example 1 is that the red mud microspheres used in Example 5 are from Preparation Example 1.1, and the addition amount is 50 g. Example 6

[0070] The difference between Example 6 and Example 1 is that the red mud microspheres used in Example 6 are from Preparation Example 1.1, and the added amount is 5 g. Example 7

[0071] The difference between Example 7 and Example 1 is that the red mud microspheres used in Example 7 are from Preparation Example 1.1, and the added amount is 70 g. Example 8

[0072] The difference between Example 8 and Example 1 is that the red mud microspheres used in Example 8 are from Preparation Example 1.2, and the addition amount is 10 g. Example 9

[0073] The difference between Example 9 and Example 1 is that the red mud microspheres used in Example 9 are from Preparation Example 1.3, and the added amount is 10 g. Example 10

[0074] The difference between Example 10 and Example 1 is that the red mud microspheres used in Example 10 are from Preparation Example 1.4, and the added amount is 10 g. Example 11

[0075] The difference between Example 11 and Example 1 is that the red mud microspheres used in Example 11 are from Preparation Example 1.5, and the addition amount is 10 g. Example 12

[0076] The difference between Example 12 and Example 1 is that the porous cerium-doped nano-iron oxide desulfurizer used in Example 12 comes from Preparation Example 2.1, and the added amount is 80 g. Example 13

[0077] The difference between Example 13 and Example 1 is that the porous cerium-doped nano-iron oxide desulfurizer used in Example 13 comes from Preparation Example 2.1, and the added amount is 100 g. Example 14

[0078] The difference between Example 14 and Example 1 is that the porous cerium-doped nano-iron oxide desulfurizer used in Example 14 comes from Preparation Example 2.1, and the added amount is 40 g. Example 15

[0079] The difference between Example 15 and Example 1 is that the porous cerium-doped nano-iron oxide desulfurizer used in Example 15 comes from Preparation Example 2.1, and the added amount is 120 g. Example 16

[0080] The difference between Example 16 and Example 1 is that the red mud microspheres used in Example 16 are from Preparation Example 2.2, and the addition amount is 60 g. Example 17

[0081] The difference between Example 17 and Example 1 is that the red mud microspheres used in Example 17 are from Preparation Example 2.3, and the addition amount is 60 g. Example 18

[0082] The difference between Example 18 and Example 1 is that the red mud microspheres used in Example 18 are from Preparation Example 2.4, and the addition amount is 60 g. Example 19

[0083] The difference between Example 19 and Example 1 is that the red mud microspheres used in Example 19 are from Preparation Example 2.5, and the added amount is 60 g. Comparative Example Comparative Example 1

[0084] The difference between Comparative Example 1 and Example 1 is that no red mud microspheres are added in Comparative Example 1. Comparative Example 2

[0085] The difference between Comparative Example 2 and Example 1 is that the porous cerium-doped nano-iron oxide desulfurizing agent is not added in Comparative Example 2. Comparative Example 3

[0086] The difference between Comparative Example 3 and Example 1 is that the desulfurizing agent used in Comparative Example 3 is 96% sodium hydroxide.

[0087] Performance testing

[0088] 1. The residual sulfur mass fraction of the calcined petroleum cokes prepared in Examples 1-19 and Comparative Examples 1-3 was measured using a microcomputer coulometric sulfur analyzer (CLS-3000). The final desulfurization rate (%) of the petroleum cokes was calculated according to the following formula. The results are shown in Table 1.

[0089] Desulfurization rate (%) = (w0-w1) / w0×100%

[0090] Wherein, w0 represents the sulfur mass fraction of petroleum coke, %;

[0091] w1 represents the residual sulfur mass fraction of calcined petroleum coke, %.

[0092] 2. The true density (g / cm2) of the calcined petroleum cokes prepared in Examples 1-19 and Comparative Examples 1-3 was measured using GB / T 4511.1 “Determination of true relative density, pseudo relative density and porosity of coke”. 3 ) were tested, and the results are shown in Table 1.

[0093] The specific test results are as follows:

[0094]

[0095] It can be seen from the test results in Table 1 that the petroleum coke calcination process provided in the present application can effectively improve the desulfurization rate of the calcined petroleum coke, and the calcined petroleum coke obtained has a high density and uniform quality.

[0096] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A petroleum coke calcining process, characterized in that: The following steps are involved: S1. After the petroleum coke was crushed, red mud microspheres were added and mixed and ball-milled, dried and sieved to obtain pretreated petroleum coke; S2. A porous cerium-doped nano-iron oxide desulfurizer was added to the pretreated petroleum coke and mixed to obtain a mixture to be calcined; S3. The mixture to be calcined was transferred to a tube furnace and heated under a nitrogen atmosphere to 750-850 ° C and kept for 1-2h to obtain desulfurized petroleum coke; after cooling naturally, the mixture was removed, washed with hydrochloric acid solution, and then washed with deionized water until the mixture was neutral, filtered, and dried; S4. The desulfurized petroleum coke after drying was calcined at 900-1200 ℃ for 3-5h to obtain calcined petroleum coke; The preparation method of the red mud microspheres comprises the following steps: After drying the red mud at 105-120°C for 24-36 hours, add plant fiber and mix evenly, then grind, dry, and pass through a 100-300 μm sieve to obtain red mud microspheres; The preparation method of the porous cerium-doped nano-iron oxide desulfurizer comprises the following steps: The plant fiber is dried and placed in a muffle furnace for pre-oxidation at 200-300°C for 2-3 hours, cooled to room temperature, immersed in water, placed for 20-30 hours, and then dried to obtain pretreated plant fiber; Cerium nitrate hexahydrate and iron nitrate hexahydrate are added to deionized water, stirred evenly, and then pretreated plant fibers are added and ultrasonically dispersed evenly; then a precipitant is added under stirring conditions of 80-90°C, stirred continuously for 2-4 hours, and then cooled to room temperature, filtered, washed several times, and then dried in an oven at 105-115°C for 4-6 hours, and then calcined at 450-550°C for 3-4 hours to obtain a porous cerium-doped nano-iron oxide desulfurizer.

2. The petroleum coke calcining process according to claim 1, wherein: In the preparation method of the red mud microspheres, the mass ratio of red mud to plant fiber is 1:0.002-0.

006.

3. The petroleum coke calcining process according to claim 1, wherein: The mass ratio of the petroleum coke to the red mud microspheres is 1:0.01-0.

05.

4. The petroleum coke calcining process according to claim 1, wherein: The porous cerium-doped nano-iron oxide desulfurizer is prepared from the following raw materials in parts by weight: 2-3 parts of cerium nitrate hexahydrate, 4-6 parts of iron nitrate hexahydrate, 200-400 parts of deionized water, 0.12-0.18 parts of plant fiber, and 3.5-7 parts of a precipitant.

5. The petroleum coke calcining process according to claim 1 or 4, characterized in that: The precipitant is ammonium carbonate.

6. The petroleum coke calcining process according to claim 1, 2 or 4, characterized in that: The plant fiber is a mixture of one or more of loofah fiber, jute fiber, straw fiber and bamboo fiber.

7. The petroleum coke calcining process according to claim 1, wherein: The mass ratio of the petroleum coke to the porous cerium-doped nano-iron oxide desulfurizer is 1:0.06-0.1.

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