A method for modifying high-sulfur petroleum coke

Abstract

This invention discloses a method for modifying high-sulfur petroleum coke. The method includes the following steps: mixing high-sulfur petroleum coke raw material with a treatment agent; performing solid-liquid separation after treatment; and washing and drying the separated solid material to obtain the product. The high-sulfur petroleum coke raw material can be further pretreated. This method can reduce the sulfur content of high-sulfur petroleum coke to below 3%, obtaining a qualified low-sulfur petroleum coke product, while simultaneously improving the performance of the petroleum coke product by more than one grade.

Description

Technical Field

[0001] This invention belongs to the field of carbon material preparation technology, and in particular relates to a method for modifying high-sulfur petroleum coke. Background Technology

[0002] The newly revised "Law of the People's Republic of China on the Prevention and Control of Atmospheric Pollution," which came into effect on January 1, 2016, requires the formulation of stricter standards for petroleum coke. The new standard for petroleum coke, NB / SH / T 0527-2015, strictly limits the sulfur content of petroleum coke: the maximum value is no more than 3 wt%. This means that the sale, import, and use of petroleum coke with a sulfur content greater than 3 wt% are subject to control.

[0003] Taking Sinopec as an example, the company's delayed coking unit has a total capacity of 39 million tons / year, producing approximately 11 million tons / year of petroleum coke, of which over 7 million tons / year is high-sulfur petroleum coke. Faced with such a large volume of high-sulfur petroleum coke, finding low-cost, clean, and efficient technologies for its conversion and utilization to improve economic efficiency has become an urgent need for Sinopec's refining and chemical enterprises. Qualified petroleum coke products are divided into 3 grades and 5 levels; each upgrade in grade brings considerable economic benefits to refining and chemical enterprises.

[0004] US Patent 3598528A preheats and oxidizes high-sulfur petroleum coke, causing partial gasification and creating pores to open hot hydrogen channels, facilitating contact and reaction between superheated hydrogen and sulfur on the petroleum coke skeleton. Chinese Patent CN200710064515 uses ionic liquids to pretreat high-sulfur petroleum coke before reacting with superheated hydrogen, achieving a desulfurization rate of 60-80%. Chinese Patent CN201010153531 uses a mixture of nitric acid and hydrochloric acid for solvent oxidation desulfurization, achieving a desulfurization rate of 45-60%. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for modifying high-sulfur petroleum coke. This modification method can reduce the sulfur content in high-sulfur petroleum coke feedstock to below 30%, while simultaneously improving the performance indicators of the petroleum coke product by more than one grade.

[0006] This invention provides a method for modifying high-sulfur petroleum coke. The modification method includes the following steps: mixing high-sulfur petroleum coke raw material with a treatment agent, performing solid-liquid separation after treatment, and washing and drying the separated solid material to obtain the product.

[0007] In the above-mentioned high-sulfur petroleum coke modification treatment method, the treatment agent is one or more of N,N-dimethylformamide, N-methylpyrrolidone, acetonitrile, furfural, o-chlorophenol, pyridine, furan, tetrahydronaphthalene, α-methylnaphthalene, ethylenediamine, and carbon disulfide, preferably one or more of ethylenediamine, N-methylpyrrolidone, and N,N-dimethylformamide, and more preferably ethylenediamine and N-methylpyrrolidone.

[0008] In the above-mentioned method for modifying high-sulfur petroleum coke, the mixing temperature of the high-sulfur petroleum coke feedstock and the treatment agent is 20–150°C, preferably 50–110°C. The ratio of the high-sulfur petroleum coke feedstock to the treatment agent is 1:1–1:200 (g / mL), preferably 1:10–1:100 (g / mL), and the treatment time is 1–72 h, preferably 8–36 h.

[0009] In the above-mentioned method for modifying high-sulfur petroleum coke, the particle size of the high-sulfur petroleum coke raw material is 10–500 μm, preferably 30–300 μm. The sulfur content of the high-sulfur petroleum coke is greater than 3 wt%, and the high-sulfur petroleum coke raw material originates from petroleum coke produced by a delayed coking unit.

[0010] In the above-mentioned method for modifying high-sulfur petroleum coke, the drying temperature is 60–150°C, preferably 80–120°C, and the drying time is 2–8 hours, preferably 4–6 hours. The drying is further preferably carried out under vacuum conditions.

[0011] In the above-mentioned high-sulfur petroleum coke modification treatment method, the washing is performed by using anhydrous ethanol as a solvent to wash the dried solid product to remove the residual treatment agent on its surface. The mass ratio of anhydrous ethanol to high-sulfur petroleum coke is 100 to 2:1, preferably 25 to 5:1.

[0012] In the above-mentioned high-sulfur petroleum coke modification treatment method, the solid-liquid separation method can be any one of filtration separation, centrifugal separation and evaporation, with filtration separation being the preferred method.

[0013] In the above-mentioned method for modifying high-sulfur petroleum coke, the high-sulfur petroleum coke raw material is further preferably pretreated before contacting with the treatment agent. The pretreatment includes the following:

[0014] (1) First, ammonium phosphate is introduced into the high-sulfur petroleum coke feedstock, and then low-temperature heat treatment is carried out;

[0015] (2) The material obtained in step (1) is processed in the presence of water vapor gas;

[0016] (3) The sample obtained in step (2) is mixed with an acid solution and then solid-liquid separation is performed. The separated solid material is washed and dried.

[0017] In the above-mentioned high-sulfur petroleum coke modification treatment method, the ammonium phosphate salt mentioned in step (1) is selected from one or more of ammonium phosphate, ammonium hydrogen phosphate, and ammonium dihydrogen phosphate, preferably ammonium phosphate.

[0018] In the above-mentioned high-sulfur petroleum coke modification method, the method of introducing ammonium phosphate into the high-sulfur petroleum coke feedstock in step (1) can be selected from, but is not limited to, one or more of the equal-volume impregnation method, supersaturated impregnation method, and kneading method, preferably the supersaturated impregnation method. For those skilled in the art, the introduction method can be selected according to methods known in the art as needed.

[0019] In the above-mentioned high-sulfur petroleum coke modification treatment method, the low-temperature heat treatment operation conditions in step (1) are: heat treatment temperature of 60-120℃, preferably 80-100℃, and heat treatment time of 2-8h, preferably 4-6h. The low-temperature heat treatment is further preferably carried out under vacuum conditions.

[0020] In the above-mentioned high-sulfur petroleum coke modification treatment method, the weight ratio of ammonium phosphate salt to high-sulfur petroleum coke in step (1) is 0.1 to 1:1, preferably 0.3 to 0.8:1.

[0021] In the above-mentioned high-sulfur petroleum coke modification method, the water vapor-containing gas in step (2) can be water vapor or a mixture of water vapor and an auxiliary gas. The auxiliary gas is nitrogen and / or an inert gas, wherein the inert gas can be one or more of helium, neon, argon, krypton, and xenon. The volume ratio of water vapor to auxiliary gas in the mixture is 1:20 to 1:1, preferably 1:10 to 1:2. The volume hourly space velocity of the water vapor-containing gas is 500 to 2000 h⁻¹. -1 .

[0022] In the above-mentioned high-sulfur petroleum coke modification treatment method, the treatment in step (2) is carried out at 120-350℃, preferably 180-320℃ for 0.2-5h, preferably 0.5-2h, and then cooled to 20-100℃, preferably 40-80℃; the cooling process is preferably carried out under nitrogen protection.

[0023] In the above-mentioned high-sulfur petroleum coke modification treatment method, the solid-liquid separation method in step (3) can be any one of the following methods: filtration separation, centrifugal separation and evaporation, with filtration separation being the preferred method.

[0024] In the above-mentioned high-sulfur petroleum coke modification treatment method, the acid mentioned in step (3) is an inorganic acid, specifically hydrochloric acid and / or nitric acid, preferably hydrochloric acid and nitric acid, and more preferably hydrochloric acid first and then nitric acid; the treatment temperature is 10-60℃, preferably 20-40℃, and the mass ratio of the sample obtained in step (2) to the acid solution is 1:0.5-1:20, preferably 1:1-1:10.

[0025] In the above-mentioned high-sulfur petroleum coke modification treatment method, the concentration of hydrochloric acid in step (3) is 5-30 wt%, preferably 10-20 wt%, and the concentration of nitric acid is 68 wt%.

[0026] In the above-mentioned high-sulfur petroleum coke modification treatment method, the washing in step (3) is mechanical washing, and the washing is carried out until neutral; the drying temperature is 60-150℃, preferably 80-120℃, and the drying time is 2-8h, preferably 4-6h.

[0027] Compared with the prior art, the high-sulfur petroleum coke modification method of the present invention has the following advantages:

[0028] 1. In the high-sulfur petroleum coke modification method of the present invention, the treatment agent used is a good hydrogen bond acceptor, which can effectively weaken the hydrogen bond forces between petroleum coke molecules, thereby achieving the removal of sulfur-containing groups in the petroleum coke raw material. Furthermore, it has strong solubility for the volatiles in petroleum coke, enabling the removal of sulfides from the volatiles. More importantly, the high-sulfur petroleum coke modification method of the present invention is carried out under relatively mild conditions, achieving effective removal of sulfides from the petroleum coke without damaging the microstructure of the petroleum coke.

[0029] 2. In the high-sulfur petroleum coke modification treatment method of the present invention, the petroleum coke is pretreated with ammonium phosphate and then treated with water vapor gas. This promotes the decomposition of ammonium phosphate in the petroleum coke to generate ammonia and phosphoric acid. The generated ammonia and phosphoric acid perform preliminary activation treatment on the petroleum coke, which improves the quality of subsequent treatment and opens up the reaction pathway.

[0030] 3. In the high-sulfur petroleum coke modification treatment method of the present invention, when the sample obtained in step (2) is mixed with acid solution, the petroleum coke reaction pathway is first cleaned by hydrochloric acid and then the petroleum coke is oxidized and upgraded by nitric acid.

[0031] 4. In the method for solvent desulfurization and upgrading of petroleum coke described in this invention, under relatively mild conditions, qualified petroleum coke products can be upgraded by more than one grade, mainly in terms of desulfurization, removal of volatile matter and reduction of ash content. Detailed Implementation

[0032] The technical content and effects of the present invention are further illustrated below with reference to embodiments, but these embodiments do not limit the present invention.

[0033] The high-sulfur petroleum coke feedstock used in the embodiments and comparative examples of the present invention has the following properties: sulfur content of 4.15 wt%, volatile matter of 15.79 wt%, and ash content of 0.79 wt%.

[0034] Example 1

[0035] Weigh 25g of ammonium phosphate and dissolve it in 200mL of deionized water to obtain solution A. Grind 100g of petroleum coke into powder and add it to solution A. Let it stand for 1.5h, then filter. Place the resulting solid sample in an oven and dry it at 90℃ for 5h. Pretreat the dried solid sample at 250℃ for 1.5h with a mixture of water vapor and nitrogen in a volume ratio of 1:2 (volume hourly space velocity of the mixed gas is 800h⁻¹). -1 The pretreated petroleum coke was then cooled to 60°C under nitrogen protection to obtain pretreated petroleum coke. The pretreated petroleum coke was further treated with 15% hydrochloric acid at a mass ratio of 1:5, and then the hydrochloric acid-treated petroleum coke was oxidized and modified with 68% nitric acid at a mass ratio of 1:10. The petroleum coke was washed with distilled water until neutral and dried at 120°C for 4 hours.

[0036] 80g of the pretreated petroleum coke obtained in the above steps was mixed with 800ml of a ethylenediamine / N-methylpyrrolidone mixed solution (0.5:1 V:V), stirred at 300 r / min for 24 h at a temperature of 80℃. After solid-liquid separation, the reaction product was washed with anhydrous ethanol and labeled as P-1.

[0037] Example 2

[0038] Weigh 10g of ammonium phosphate and dissolve it in 200mL of deionized water to obtain solution A. Grind 100g of petroleum coke into powder and add it to solution A. Let it stand for 1.5h, then filter. Place the resulting solid sample in an oven and dry it at 90℃ for 5h. Pretreat the dried solid sample at 250℃ for 1.5h with a mixture of water vapor and nitrogen in a volume ratio of 1:2 (volume hourly space velocity of the mixed gas is 800h⁻¹). -1 The pretreated petroleum coke was then cooled to 60°C under nitrogen protection to obtain pretreated petroleum coke. The pretreated petroleum coke was further treated with 15% hydrochloric acid at a mass ratio of 1:5, and then the hydrochloric acid-treated petroleum coke was oxidized and modified with 68% nitric acid at a mass ratio of 1:10. The petroleum coke was washed with distilled water until neutral and dried at 120°C for 4 hours.

[0039] 80g of the pretreated petroleum coke obtained in the above steps was mixed with 800ml of acetonitrile, stirred at 300 r / min for 24h, and treated at 80℃. After solid-liquid separation, the reaction product was washed with anhydrous ethanol and labeled as P-2.

[0040] Example 3

[0041] Weigh 25g of ammonium phosphate and dissolve it in 200mL of deionized water to obtain solution A. Grind 100g of petroleum coke into powder and add it to solution A. Let it stand for 1.5h, then filter. Place the resulting solid sample in an oven and dry it at 90℃ for 5h. Pretreat the dried solid sample at 250℃ for 1.5h with a mixture of water vapor and nitrogen in a volume ratio of 1:2 (volume hourly space velocity of the mixed gas is 800h⁻¹). -1 The pretreated petroleum coke was then cooled to 60°C under nitrogen protection to obtain pretreated petroleum coke. The pretreated petroleum coke was further treated with 15% hydrochloric acid at a mass ratio of 1:5, and then the hydrochloric acid-treated petroleum coke was oxidized and modified with 68% nitric acid at a mass ratio of 1:10. The petroleum coke was washed with distilled water until neutral and dried at 120°C for 4 hours.

[0042] 80g of the pretreated petroleum coke obtained in the above steps was mixed with 800ml of N-methylpyrrolidone, stirred at 300r / min for 24h, and treated at 80℃. After solid-liquid separation, the reaction product was washed with anhydrous ethanol and labeled as P-3.

[0043] Example 4

[0044] 80g of the pretreated petroleum coke obtained in the above steps was mixed with 8000ml of N,N-dimethylformamide, stirred at 300 r / min for 24h, and treated at 110℃. After solid-liquid separation, the reaction product was washed with anhydrous ethanol and labeled as P-4.

[0045] Example 5

[0046] 80g of the pretreated petroleum coke obtained in the above steps was mixed with 800ml of ethylenediamine, and the mixture was stirred at 300 r / min for 36 h at a temperature of 80℃. After solid-liquid separation, the reaction product was washed with anhydrous ethanol and labeled as P-5.

[0047] Example 6

[0048] 80g of the pretreated petroleum coke obtained in the above steps was mixed with 800ml of furfural, stirred at 300 r / min for 8 hours at a temperature of 80℃. After solid-liquid separation, the reaction product was washed with anhydrous ethanol and labeled as P-6.

[0049] Example 7

[0050] 80g of petroleum coke was mixed with 800ml of a 0.5:1 V:V solution of ethylenediamine and N-methylpyrrolidone, stirred at 300 r / min for 24 h at a temperature of 80℃. The reaction product was then separated into solid and liquid phases and washed with distilled water until neutral. The product was labeled P-7.

[0051] Comparative Example 1

[0052] Weigh 25g of ammonium phosphate and dissolve it in 200mL of deionized water to obtain solution A. Grind 100g of petroleum coke into powder and add it to solution A. Let it stand for 1.5h, then filter. Place the resulting solid sample in an oven and dry it at 90℃ for 5h. Pretreat the dried solid sample at 250℃ for 1.5h with a mixture of water vapor and nitrogen in a volume ratio of 1:2 (volume hourly space velocity of the mixed gas is 800h⁻¹). -1 The pretreated petroleum coke was then cooled to 60°C under nitrogen protection to obtain pretreated petroleum coke. The pretreated petroleum coke was further treated with 15% hydrochloric acid at a mass ratio of 1:5, and then the hydrochloric acid-treated petroleum coke was oxidized and modified with 68% nitric acid at a mass ratio of 1:10. The petroleum coke was washed with distilled water until neutral and dried at 120°C for 4 hours. The product was labeled D-1.

[0053] Table 1 Properties of Petroleum Coke Products

[0054] petroleum coke Sulfur content, wt.% Ash content, wt.% Volatile matter, wt.% grade P-1 1.15 0.35 8.19 2B P-2 1.95 0.51 11.60 3A P-3 1.49 0.39 8.61 2B P-4 1.63 0.43 9.47 3A P-5 1.82 0.49 10.01 3A P-6 2.79 0.56 13.77 3B P-7 1.78 0.45 9.89 3A D-1 4.14 0.78 15.69 Unqualified

Claims

1. A method for modifying high-sulfur petroleum coke, the method comprising the following steps: mixing high-sulfur petroleum coke raw material with a treatment agent, performing solid-liquid separation after treatment, and washing and drying the separated solid material to obtain the product; wherein the treatment agent is ethylenediamine and N-methylpyrrolidone; The high-sulfur petroleum coke feedstock undergoes pretreatment before contacting with the treatment agent. The pretreatment includes the following steps: (1) First, ammonium phosphate is introduced into the high-sulfur petroleum coke feedstock, and then low-temperature heat treatment is carried out; (2) The material obtained in step (1) is processed in the presence of water vapor gas; (3) The sample obtained in step (2) is first treated with hydrochloric acid, then with nitric acid, and then solid-liquid separation is performed. The separated solid material is washed and dried. in, The low-temperature heat treatment operating conditions in step (1) are: heat treatment temperature of 60-90℃ and heat treatment time of 2-8h; The weight ratio of ammonium phosphate to high-sulfur petroleum coke in step (1) is 0.1 to 1:1; The concentration of hydrochloric acid in step (3) is 5wt%~30wt%.

2. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The mixing temperature of the high-sulfur petroleum coke feedstock and the treatment agent is 20–150°C.

3. The method for modifying high-sulfur petroleum coke according to claim 2, characterized in that: The mixing temperature of the high-sulfur petroleum coke feedstock and the treatment agent is 50–110°C.

4. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The ratio of high-sulfur petroleum coke feedstock to treatment agent is 1:1 to 1:200 (g / mL), and the treatment time of high-sulfur petroleum coke feedstock and treatment agent is 1 to 72 hours.

5. The method for modifying high-sulfur petroleum coke according to claim 4, characterized in that: The ratio of high-sulfur petroleum coke feedstock to treatment agent is 1:10 to 1:100 (g / mL), and the treatment time of high-sulfur petroleum coke feedstock and treatment agent is 8 to 36 hours.

6. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The high-sulfur petroleum coke feedstock has a particle size of 10–500 μm and a sulfur content of more than 3 wt%.

7. The method for modifying high-sulfur petroleum coke according to claim 6, characterized in that: The particle size of the high-sulfur petroleum coke feedstock is 30–300 μm.

8. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The drying temperature is 60–150℃, and the drying time is 2–8 hours.

9. The method for modifying high-sulfur petroleum coke according to claim 8, characterized in that: The drying temperature is 80–120°C, and the drying time is 4–6 hours.

10. The method for modifying high-sulfur petroleum coke according to claim 8, characterized in that: The drying process is carried out under vacuum conditions.

11. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The washing process involves using anhydrous ethanol as a solvent to wash the dried solid product, with the mass ratio of anhydrous ethanol to high-sulfur petroleum coke being 100 to 2:

1.

12. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The mass ratio of anhydrous ethanol to high-sulfur petroleum coke is 25 to 5:

1.

13. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The ammonium phosphate salt mentioned in step (1) is selected from one or more of ammonium phosphate, ammonium hydrogen phosphate, and ammonium dihydrogen phosphate.

14. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The low-temperature heat treatment operating conditions in step (1) are: heat treatment temperature of 80-90℃ and heat treatment time of 4-6h.

15. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The low-temperature heat treatment is performed under vacuum conditions.

16. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The weight ratio of ammonium phosphate to high-sulfur petroleum coke in step (1) is 0.3 to 0.8:

1.

17. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The water vapor-containing gas in step (2) is water vapor or a mixture of water vapor and an auxiliary gas, wherein the auxiliary gas is nitrogen and / or an inert gas, and the inert gas is one or more of helium, neon, argon, krypton, and xenon; the volume ratio of water vapor to auxiliary gas in the mixture is 1:20 to 1:1, and the volume hourly space velocity of the water vapor-containing gas is 500 to 2000 h⁻¹. -1 .

18. The method for modifying high-sulfur petroleum coke according to claim 17, characterized in that: The volume ratio of water vapor to auxiliary gas in the mixed gas is 1:10 to 1:

2.

19. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The treatment in step (2) is to treat at 120-350℃ for 0.2-5 hours, and then cool down to 20-100℃.

20. The method for modifying high-sulfur petroleum coke according to claim 19, characterized in that: The treatment in step (2) is carried out at 180-320℃ for 0.5-2 hours, and then cooled to 40-80℃; the cooling process is carried out under nitrogen protection.

21. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: In step (3), the processing temperature is 10 to 60°C.

22. The method for modifying high-sulfur petroleum coke according to claim 21, characterized in that: In step (3), the processing temperature is 20-40℃.

23. The method for modifying high-sulfur petroleum coke according to claim 1, characterized in that: The drying temperature in step (3) is 60-150℃ and the drying time is 2-8h.

24. The method for modifying high-sulfur petroleum coke according to claim 23, characterized in that: The drying temperature in step (3) is 80-120℃ and the drying time is 4-6h.