Preparation method of desulfurization adsorbent

Abstract

The invention discloses a preparation method of a desulfurization adsorbent, which comprises the following steps: preparing an aqueous solution of nickel salt and copper salt, adding carrier activated carbon, adding a precipitant aqueous solution, controlling the pH value of the solution to be 5.5-6.5, stirring until the solution is uniform, slowly heating under vacuum until the moisture content is less than or equal to 8%, adding ethylene glycol, replenishing a precipitant, heating to reflux temperature while stirring, and cooling to room temperature to obtain the desulfurization adsorbent. And cooling to room temperature after the reaction, washing off the water-soluble inorganic salt with water, and drying in vacuum to obtain the desulfurization adsorbent. The prepared adsorbent copper hydroxide is deposited and loaded on the surface of activated carbon, hydrogen sulfide and mercaptan are treated preferentially, internal nickel is protected to only act with thioether, thiophene and the like, and the removal quantity and the removal depth of thioether and thiophene are increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of adsorbents, in particular to a preparation method of a desulfurization adsorbent. BACKGROUND

[0002] With the increasingly stringent environmental protection requirements, the limit value of sulfur content in gasoline is continuously reduced by the state, and how to deeply remove sulfur is an insurmountable problem in the field of petroleum chemical industry.

[0003] When the traditional hydrofining desulfurization is used for desulfurization of gasoline product, in addition to the requirement of high temperature and high pressure for operation conditions, a large amount of hydrogen is consumed, olefins are easily saturated, and the octane number of gasoline is significantly reduced. At present, the adsorption desulfurization which is studied more has the advantages of mild operation conditions, small octane number loss and simple process flow, so the adsorption desulfurization technology is one of the hotspots for deep desulfurization research. The application of the adsorption desulfurization technology requires that the adsorbent has good sulfur adsorption performance and good selective adsorption capacity for sulfides.

[0004] According to different adsorption mechanisms, the adsorption desulfurization is divided into physical adsorption desulfurization and chemical adsorption desulfurization, and according to different carriers of adsorbents, the adsorbents include molecular sieve-based desulfurization adsorbent, metal oxide-based desulfurization adsorbent, activated carbon-based desulfurization adsorbent and clay-based desulfurization adsorbent. The main process of the chemical adsorption desulfurization technology is the S-Zorb sulfur removal technology of Phillips Petroleum Company. The adsorbent is carried by Ni and other metals on a composite carrier, the composite carrier is a mixture of zinc oxide, silica and alumina, the adsorbent can adsorb sulfur-containing compound molecules, remove sulfur atoms, make the sulfur atoms in the molecules remain on the adsorbent, and release the hydrocarbon part. In addition to Phillips Petroleum Company, other companies also prepare adsorbents for research and testing by using different single carriers, different composite carriers and different active metal ratios. SUMMARY

[0005] In view of the problems existing in the current desulfurization adsorbent, the present application provides a preparation method of a desulfurization adsorbent, and the steps are as follows: S1, a water solution of nickel salt and copper salt is prepared, a carrier activated carbon is added, stirring is uniformly carried out, a primary mixed solution is obtained, a water solution of a precipitant is prepared, under stirring, the water solution of the precipitant is added to the primary mixed solution, the pH value of the solution is controlled to be 5.5-6.5, and stirring is continuously carried out until a uniform suspension is formed, in which most of the copper ions are precipitated, and a small part of the nickel ions are precipitated; S2, the suspension obtained in step S1 is slowly heated and kept at a constant temperature for a certain time under vacuum until the water content in the material is ≤8%, at this time, the nickel ions in the solution enter the pore channel of the activated carbon, and the copper hydroxide is wrapped on the outer surface of the activated carbon.

[0006] S3, adding ethylene glycol to the powder obtained in step S2, starting stirring, and adding the precipitant, continuing stirring until mixed evenly, and heating to reflux temperature under stirring, and then cooling to room temperature.

[0007] S4, washing the material obtained in step S3 with deionized water to remove water-soluble inorganic salts, and drying under vacuum to obtain the desulfurization adsorbent.

[0008] In step S1, when the pH is controlled to be between 5.5 and 6.5, most of the copper salt forms copper hydroxide precipitate, while a large amount of nickel ions remain in the solution. It is further preferred that the pH in step S1 is controlled to be between 6.0 and 6.5.

[0009] In the desulfurization adsorbent obtained in step S4, the weight ratio of the content of nickel and copper to the weight of activated carbon after reduction to form elemental copper and elemental nickel is 0.2-0.4:1.

[0010] In step S1, the nickel salt and the copper salt each independently include any one or several of nitrate, sulfate, chloride, acetate. For example, the nickel salt can be selected from nickel nitrate, nickel sulfate, nickel chloride, and nickel acetate, and the copper salt can be selected from copper nitrate, copper sulfate, copper chloride, and copper acetate. It is further preferred that the nickel salt and the copper salt are selected from nitrate and sulfate.

[0011] In steps S1 and S3, the precipitant includes one or both of sodium hydroxide and potassium hydroxide. In step S1, the addition ratio of the copper salt to the nickel salt is Cu:Ni=1:3-27 in terms of the moles of Cu and Ni elements.

[0012] It is further preferred that the addition ratio of the copper salt to the nickel salt is Cu:Ni=1:6-15 in terms of the moles of Cu and Ni elements.

[0013] In step S1, the solution concentration of the copper salt and the nickel salt is 0.3-1 mol / L.

[0014] The aqueous solution concentration of the precipitant is 0.5-1.5 mol / L.

[0015] In step S1, the amount of the precipitant added is determined according to the required pH value. In step S2, the vacuum degree is 0.03-0.08 MPa, and the heating temperature is 40-80°C.

[0016] In step S3, the addition amount of ethylene glycol is 0.05-0.1 g / mL of the powder in step (2) in ethylene glycol solution. In step S3, the amount of the precipitant added is 0.5-8% of the weight of ethylene glycol.

[0017] In step S3, the temperature is raised to 105-170℃, and the reaction time is 4-8 hours.

[0018] In the adsorbent prepared by this invention, most of the elemental nickel is loaded in the internal pores of the activated carbon, and most of the elemental copper is loaded on the surface of the activated carbon.

[0019] The adsorbent regeneration process of this invention is as follows: The desulfurized adsorbent is added to an aqueous solution and the pH is adjusted to less than 3 with sulfuric acid, nitric acid or hydrochloric acid while stirring. An oxidant (sodium hypochlorite, chlorine dioxide, hydrogen peroxide or ozone) is added while stirring and the reaction is carried out for 0.5-2 hours. This can convert copper sulfide and nickel sulfide into copper sulfate and nickel sulfate. The active desulfurization adsorbent is then obtained through the aforementioned preparation steps and reduction.

[0020] The beneficial effects of this invention are as follows: 1. Copper-nickel adsorbents are prepared by precipitation. During precipitation, the pH value of the system is strictly controlled so that most of the copper ions precipitate to form copper hydroxide, while most of the nickel ions do not undergo precipitation but enter the pores of the carrier. Copper hydroxide is deposited on the surface of activated carbon, while most of the nickel enters the pores of activated carbon and is loaded inside the pores. 2. The adsorbent prepared by this patent has elemental copper and nickel particles at the nanoscale, with uniform dispersion, resulting in a large interaction area with sulfides and high utilization of copper and nickel. The copper on the outer surface of the adsorbent has a stronger adsorption and fixation capacity for sulfides, preferentially removing hydrogen sulfide and thiols, while protecting the elemental nickel inside the activated carbon channels to react only with sulfides and thiophenes, thereby enhancing the removal quantity and depth of sulfides and thiophenes, and ultimately improving the overall treatment capacity for sulfur-containing compounds. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments, so that those skilled in the art can better understand and implement the present invention, but the embodiments are not intended to limit the present invention.

[0022] Example 1 (1) Weigh 12g of Cu(NO3)2·3H2O and 145g of Ni(NO3)2·6H2O, dissolve them in 500mL of deionized water to prepare a solution, add 108g of activated carbon to the solution, and stir evenly to form a mixed solution. Prepare a sodium hydroxide aqueous solution with a concentration of 1.2 mol / L. Slowly add the sodium hydroxide solution dropwise to the mixed solution while stirring. Use a pH meter to accurately monitor the pH value of the solution to 6.0 ± 0.2. Continue stirring until a suspension is formed.

[0023] (2) The suspension obtained in step (1) is slowly heated to 50°C under vacuum, and the vacuum degree is maintained at 0.04-0.07 MPa for 5 hours until the moisture content in the material is 6.8%; (3) Add ethylene glycol to the material obtained in step (2). The concentration of the material in the ethylene glycol solution is 0.1 g / mL. Start stirring, add precipitant, the amount of precipitant is 1% of the weight of ethylene glycol, until the mixture is uniform, heat to 110°C under stirring, and cool to room temperature after 5 hours of reaction.

[0024] (4) Wash the material obtained in step (3) with deionized water to remove water-soluble inorganic salts. After four washes, the conductivity of the filtrate is 38 μS / cm. Then, after vacuum drying at 70°C, the desulfurization adsorbent is obtained.

[0025] Example 2 (1) Weigh 12g of CuSO4·5H2O and 105g of NiSO4·6H2O, dissolve them in 500mL of deionized water to prepare a solution, add 76g of activated carbon to the solution, and stir evenly to form a mixed solution. Prepare a sodium hydroxide aqueous solution with a concentration of 1.2 mol / L. Slowly add the sodium hydroxide solution dropwise to the mixed solution while stirring. Use a pH meter to accurately monitor the pH value of the solution to 6.0 ± 0.2. Continue stirring until a suspension is formed.

[0026] (2) The suspension obtained in step (1) is slowly heated to 60°C under vacuum, and the vacuum degree is maintained at 0.04-0.07 MPa for 4 hours until the moisture content in the material is 7.5%; (3) Add ethylene glycol to the material obtained in step (2). The concentration of the material in the ethylene glycol solution is 0.08 g / mL. Start stirring, add precipitant, and add 3% of the weight of ethylene glycol until the mixture is uniform. Heat to 130°C while stirring, and cool to room temperature after 5 hours of reaction.

[0027] (4) Wash the precipitate obtained in step S3 with deionized water to remove water-soluble inorganic salts. After 5 washes, the conductivity of the filtrate is 35 μS / cm. Then, after vacuum drying at 70℃, the desulfurization adsorbent is obtained.

[0028] Example 3 (1) Weigh 10g of Cu(CH3COO)2·H2O and 62g of Ni(CH3COO)2·4H2O, dissolve them in 400mL of deionized water to prepare a solution, add 71g of activated carbon to the solution, and stir evenly to form a mixed solution. Prepare a sodium hydroxide aqueous solution with a concentration of 1 mol / L. Slowly add the sodium hydroxide solution dropwise to the mixed solution while stirring. Use a pH meter to accurately monitor the pH value of the solution to 5.8 ± 0.2. Continue stirring until a suspension is formed.

[0029] (2) The suspension obtained in step (1) is slowly heated to 60°C under vacuum, and the vacuum degree is maintained at 0.05-0.08 MPa for 6 hours until the moisture content in the material is 6.5%; (3) Add ethylene glycol to the material obtained in step (2). The concentration of the material in the ethylene glycol solution is 0.1 g / mL. Start stirring and add 4% by weight of ethylene glycol as precipitant until the mixture is uniform. Heat to 150°C while stirring and cool to room temperature after 5 hours of reaction.

[0030] (4) Wash the material obtained in step S3 with deionized water to remove water-soluble inorganic salts. After 5 washes, the conductivity of the filtrate is 35 μS / cm. Then, after vacuum drying at 70℃, the desulfurization adsorbent is obtained.

[0031] The adsorbents in Examples 1, 2, and 3 were tested using SEM-EDS to determine the elemental content ratio between the sample surface and interior. Surface scanning was used, and multiple tests were conducted to obtain the average value. Table 1 shows the Cu:Ni values ​​(atomic ratio) of the surface and interior of the products obtained in Examples 1, 2, and 3.

[0032] Table 1 Example Surface elemental ratio / Cu: Ni atomic ratio Internal elemental ratio / Cu: Ni atomic ratio Example 1 0.95 0.005 Example 2 1.19 0.007 Example 3 1.9 0.01 The adsorbents obtained in Examples 1, 2, and 3 were applied to the desulfurization reaction: Catalytic cracked gasoline was used as feedstock, and its sulfur content was tested to be 998 ppm. The adsorbent was mixed evenly with the sample to be desulfurized, and the amount of adsorbent added was such that the total molar amount of copper and nickel in the adsorbent was equal to the molar amount of sulfur in the adsorbent, which was 1.5:1. The mixture was heated to 100°C and treated for 1 hour. After the reaction, the material was filtered, and the liquid was distilled under reduced pressure to obtain the desulfurized sample.

[0033] After treatment using the above method, the sulfur content in the desulfurized sample was tested, as shown in Table 2. A sulfur content of less than 10 ppm indicates deep desulfurization.

[0034] Table 2 Example Sulfur content / ppm Example 1 5.6 Example 2 8.2 Example 3 7.3

Claims

1. A method for preparing a desulfurization adsorbent, characterized in that... Preparation steps include S1. Prepare aqueous solutions of nickel and copper salts, add activated carbon as a carrier, stir evenly to obtain a primary mixture, prepare an aqueous solution of precipitant, add the aqueous solution of precipitant to the primary mixture while stirring, control the pH value of the solution to 5.5-6.5, continue stirring until a uniform suspension is formed, in which most of the copper ions precipitate and a small portion of the nickel ions precipitate. S2. The suspension obtained in step S1 is slowly heated under vacuum and kept at a constant temperature for a certain period of time until the moisture content in the material is ≤8%. S3. Add ethylene glycol to the powder obtained in step S2, start stirring, add precipitant, continue stirring until the mixture is uniform, heat to reflux temperature while stirring, react for a certain time, and then cool to room temperature. S4. Wash the material obtained in step S3 with deionized water to remove water-soluble inorganic salts, and then vacuum dry to obtain the desulfurization adsorbent.

2. The method for preparing a desulfurization adsorbent according to claim 1, characterized in that, The content of nickel and copper in the desulfurization adsorbent, calculated as elemental copper and elemental nickel after reduction, is in a weight ratio of 0.2-0.4:1 with activated carbon.

3. The method for preparing a desulfurization adsorbent according to claim 1, characterized in that... The nickel salt and copper salt mentioned in step S1 each independently include any one or more of nitrates, sulfates, chlorides, and acetates.

4. The method for preparing a desulfurization adsorbent according to claim 1, characterized in that... The precipitant in steps S1 and S3 includes one or both of sodium hydroxide and potassium hydroxide.

5. The method for preparing a desulfurization adsorbent according to claim 1, characterized in that... In step S1, the ratio of copper salt to nickel salt is calculated in molar amounts of Cu and Ni: Cu:Ni = 1:3-27.

6. The method for preparing a desulfurization adsorbent according to claim 1, characterized in that... In step S1, the concentration of the copper salt and nickel salt solution is 0.3-1 mol / L, and the concentration of the aqueous solution of the precipitant is 0.5-1.5 mol / L.

7. The method for preparing a desulfurization adsorbent according to claim 1, characterized in that... The vacuum degree in step S2 is 0.03-0.08 MPa, and the heating temperature is 40-80℃.

8. The method for preparing a desulfurization adsorbent according to claim 1, characterized in that... The amount of ethylene glycol added in step S3 is such that the concentration of the powder in step (2) in the ethylene glycol solution is 0.05 to 0.1 g / mL.

9. The method for preparing a desulfurization adsorbent according to claim 1, characterized in that... The amount of precipitant added in step S3 is 0.5-8% of the weight of ethylene glycol.

10. The method for preparing a desulfurization adsorbent according to claim 1, characterized in that... In step S3, the temperature is raised to 105-170℃, and the reaction time is 4-8 hours.