阅读说明：本技术 一种含硼拟薄水铝石的制备方法 (Preparation method of boron-containing pseudo-boehmite ) 是由 何海龙 张振振 查春鸿 栾福冰 李孝华 郭德凯 刘珺珺 于 2020-05-19 设计创作，主要内容包括：本发明涉及一种含硼拟薄水铝石的制备方法,包括以下步骤：将硼酸盐粉碎,待用；分别配制含铝碱性溶液、硫酸铝溶液、硫酸铵溶液；将硼酸盐粉加入含铝碱性溶液中配制成铝硼碱性悬浊液；向反应釜中加入底水,启动搅拌并加热,将硫酸铝溶液加入至反应釜中,同时并流加入铝硼碱性悬浊液,通过调整铝硼碱性悬浊液流速控制反应釜内浆液pH值,并保持反应釜内浆液温度恒定,反应一段时间后结束反应；向反应釜中加入硫酸铵溶液调整反应釜内浆液pH值,之后浆液进行老化、洗涤、干燥,得到含硼拟薄水铝石。本发明制备的含硼氧化铝硼不流失,具有较大的孔容和适宜的表面积及较高的B酸含量,特别适合用作重质馏分油、渣油加氢处理催化剂。(The invention relates to a preparation method of boron-containing pseudo-boehmite, which comprises the following steps: crushing borate for later use; respectively preparing an aluminum-containing alkaline solution, an aluminum sulfate solution and an ammonium sulfate solution; adding borate powder into an aluminum-containing alkaline solution to prepare an aluminum-boron alkaline suspension; adding bottom water into a reaction kettle, starting stirring and heating, adding an aluminum sulfate solution into the reaction kettle, simultaneously adding an aluminum boron alkaline suspension in a concurrent flow manner, controlling the pH value of the slurry in the reaction kettle by adjusting the flow rate of the aluminum boron alkaline suspension, keeping the temperature of the slurry in the reaction kettle constant, and finishing the reaction after reacting for a period of time; and adding an ammonium sulfate solution into the reaction kettle to adjust the pH value of the slurry in the reaction kettle, and then aging, washing and drying the slurry to obtain the boron-containing pseudo-boehmite. The boron-containing alumina prepared by the method has no loss, larger pore volume, proper surface area and higher B acid content, and is particularly suitable for being used as a heavy distillate oil and residual oil hydrotreating catalyst.)

1. The preparation method of the boron-containing pseudo-boehmite is characterized by comprising the following steps of:

(1) pulverizing borate to a certain particle size for later use;

(2) respectively preparing an aluminum-containing alkaline solution and an aluminum sulfate solution with certain alumina content, and then preparing an ammonium sulfate solution with certain ammonium sulfate content;

(3) adding borate powder into an aluminum-containing alkaline solution according to a certain proportion to prepare an aluminum-boron alkaline suspension;

(4) adding bottom water into a reaction kettle, starting stirring and heating to reaction temperature, adding an aluminum sulfate solution into the reaction kettle at a certain speed, simultaneously adding an aluminum boron alkaline suspension in a concurrent flow manner, controlling the pH value of the slurry in the reaction kettle by adjusting the flow rate of the aluminum boron alkaline suspension, keeping the temperature of the slurry in the reaction kettle constant, and finishing the reaction after reacting for a period of time;

(5) and after the reaction is finished, adding an ammonium sulfate solution into the reaction kettle to adjust the pH value of the slurry in the reaction kettle, then aging the slurry, and washing and drying the aged slurry to obtain the boron-containing pseudo-boehmite.

2. The method according to claim 1, wherein the borate is boromagnesite (Mg) powder₂B₂O₅·H₂O); the granularity is 250-450 meshes; the boron content in the boron-magnesium mineral powder is 10wt% -12 wt%.

3. The method according to claim 2, wherein in the step (1), the borate has a particle size of 300 to 400 mesh.

4. The method for preparing pseudo-boehmite containing boron according to claim 1, characterized in that in the step (2), the alkaline solution containing aluminum is one or more of sodium metaaluminate solution or potassium metaaluminate solution;

the caustic ratio of the aluminum-containing alkaline solution is 1.1-1.3; the concentration of the aluminum-containing alkaline solution is Al₂O₃The amount is 100-300 g/L;

the concentration of the aluminum sulfate solution is Al₂O₃The weight is 40-100 g/L;

the content of ammonium sulfate in the ammonium sulfate solution is 100-400 g/L, preferably 150-300 g/L.

5. The method for preparing pseudo-boehmite containing boron according to claim 4, characterized in that in the step (2), the alkaline solution containing aluminum is a sodium metaaluminate solution; the caustic ratio of the aluminum-containing alkaline solution is 1.15-1.25; the concentration of the aluminum-containing alkaline solution is Al₂O₃The weight is 150-250 g/L; the concentration of the aluminum sulfate solution is Al₂O₃Calculated as 50-80 gAl₂O₃L; the ammonium sulfate content in the ammonium sulfate solution is 150-300 g/L.

6. The method for preparing pseudo-boehmite containing boron according to claim 1, characterized in that in the step (3), the content of ascharite powder in the aluminoboron alkaline suspension is 5-50 g/L.

7. The method for preparing pseudo-boehmite containing boron according to claim 1, characterized in that in the step (4), the amount of the bottom water added into the reaction kettle is 1/10-1/5 of the volume of the reaction kettle; the reaction temperature is 50-90 ℃; the adding speed of the aluminum sulfate solution is 20mL/min to 40 mL/min; controlling the pH value of the slurry obtained in the reaction kettle to be 8.5-9.5 by adjusting the flow rate of the aluminum boron alkaline suspension; the reaction time is 40-90 min.

8. The method for preparing pseudo-boehmite containing boron according to claim 1, characterized in that in the step (5), after the reaction is finished, ammonium sulfate solution is added into the reaction kettle to adjust the pH value of the slurry in the reaction kettle to 7.3-8.3; the aging condition is that the temperature is 80-90 ℃ and the time is 30-120 min.

9. The method for preparing pseudo-boehmite containing boron according to claim 1, characterized in that in the step (5), washing is performed with deionized water at 55-65 ℃; the drying conditions are as follows: the temperature is 100-150 ℃ and the time is 6-10 hours.

Technical Field

The invention relates to a preparation method of boron-containing pseudo-boehmite, in particular to a preparation method of large-pore-volume and large-pore-diameter boron-containing pseudo-boehmite which is suitable for being used as a carrier material of inferior residual oil hydrotreating catalysts.

Background

γ-Al₂O₃Alumina is used as a catalytic material and has very wide application in the field of catalysis, particularly the field of catalytic hydrogenation. Preparation of gamma-Al₂O₃The common method is to prepare pseudo-boehmite and then to be baked and converted into gamma-Al at a certain temperature₂O₃。

The carrier prepared by pure alumina has weak acidity, mainly contains L acid, and B acid is very weak or does not contain B acid, and is easy to have strong interaction with active metal components to form inactive species, thereby influencing the performance of the catalyst. Therefore, when the catalyst carrier is prepared from alumina, one or more auxiliary agents are usually added to adjust the acidity of the catalyst and/or improve the interaction between the active component and the carrier.

The catalyst auxiliary can be divided into structural auxiliary and modifying auxiliary in terms of type and performance, forFor pseudo-boehmite, boron is a more ideal structural auxiliary agent, and the addition of boron can effectively increase the pore volume and the specific surface area of the pseudo-boehmite; for Mo-Ni/Al₂O₃Or Mo-Co/Al₂O₃For the hydrogenation catalyst, boron is an ideal modifying assistant, and can improve the acidity of the catalyst, and meanwhile, Mo₇O₂₄ ^6-And B³⁺Action ratio of Al³⁺Strong of (2) octahedron Ni²⁺Or Co²⁺So that more CoMoO or NiMoO is on the surface of the carrier, more hydrogenation active centers are generated, and the activity of the catalyst is improved.

At present, in the preparation process of the catalyst, the auxiliary agent boron is usually added by adopting a dipping method, a kneading method, a precipitation method and the like, and is also added in the process of preparing the pseudo-boehmite.

CN200510046347.0 discloses an alumina dry glue containing silicon and boron and a preparation method thereof. The boron is added in two ways: firstly, after aging, washing and filtering, pulping the wet filter cake, heating to 30-90 ℃, and directly adding the boron-containing compound into the slurry. Secondly, after aging, washing and filtering, adding the wet filter cake into a boron-containing compound aqueous solution at the temperature of 30-90 ℃, and then washing, filtering and drying to obtain the alumina dry glue. The method has certain defects in the production process, the addition of boron needs pulping and secondary aging, the production flow is increased, and the process is complex.

CN102451771A and CN102039196A divide and develop a boron-containing alumina carrier and its preparation method, the synthetic method of the boron-containing aluminium hydroxide dry glue used for preparing the carrier is: carrying out neutralization gelling reaction on an aluminum-containing inorganic salt solution and a precipitator at a certain temperature, adding an organic alcohol solution containing boric acid after the reaction, adjusting the pH value to 5.0-10.0, starting aging at 50-90 ℃, washing and drying to obtain the boron-containing aluminum hydroxide. The method adds an organic solution containing boric acid after reaction, so that the boric acid is adsorbed on aluminum hydroxide crystal grains, partial boron loss is caused, meanwhile, the boric acid is dissolved in organic alcohol such as mannitol, glycol and glycerol, certain organic alcohol is dissolved in washing water and discharged when washing, and certain influence is caused on the environment.

Therefore, how to reduce the loss of the auxiliary boron and obtain larger pore volume and specific surface area in the preparation process of the catalyst is a technical problem which is always desired to be solved in the field.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a boron-containing pseudo-boehmite and a preparation method thereof. The boron-containing alumina obtained by roasting the boron-containing pseudo-boehmite has the advantages of large pore volume, large specific surface area, centralized pore distribution and the like.

The invention relates to a preparation method of boron-containing pseudo-boehmite, which comprises the following steps:

(1) pulverizing borate to a certain particle size for later use;

(2) respectively preparing an aluminum-containing alkaline solution and an aluminum sulfate solution with certain alumina content, and then preparing an ammonium sulfate solution with certain ammonium sulfate content;

(3) adding borate powder into an aluminum-containing alkaline solution according to a certain proportion to prepare an aluminum-boron alkaline suspension;

(4) adding bottom water into a reaction kettle, starting stirring and heating to reaction temperature, adding an aluminum sulfate solution into the reaction kettle at a certain speed, simultaneously adding an aluminum boron alkaline suspension in a concurrent flow manner, controlling the pH value of the slurry in the reaction kettle by adjusting the flow rate of the aluminum boron alkaline suspension, keeping the temperature of the slurry in the reaction kettle constant, and finishing the reaction after reacting for a period of time;

(5) and after the reaction is finished, adding an ammonium sulfate solution into the reaction kettle to adjust the pH value of the slurry in the reaction kettle, then aging the slurry, and washing and drying the aged slurry to obtain the boron-containing pseudo-boehmite.

Wherein in the step (1), the borate is boron magnesium ore powder (Mg)₂B₂O₅·H₂O); the granularity is 250-450 meshes; the boron content in the boron-magnesium mineral powder is 10wt% -12 wt%.

In the step (2), the aluminum-containing alkaline solution is one or more of a sodium metaaluminate solution and a potassium metaaluminate solution;

the above-mentionedThe caustic ratio of the aluminum-containing alkaline solution is 1.1-1.3; the concentration of the aluminum-containing alkaline solution is Al₂O₃The amount is 100-300 g/L;

the concentration of the aluminum sulfate solution is Al₂O₃The weight is 40-100 g/L;

the content of ammonium sulfate in the ammonium sulfate solution is 100-400 g/L, preferably 150-300 g/L.

In the step (2), the aluminum-containing alkaline solution is a sodium metaaluminate solution; the caustic ratio of the aluminum-containing alkaline solution is 1.15-1.25; the concentration of the aluminum-containing alkaline solution is Al₂O₃The weight is 150-250 g/L; the concentration of the aluminum sulfate solution is Al₂O₃Calculated as 50-80 gAl₂O₃L; the ammonium sulfate content in the ammonium sulfate solution is 150-300 g/L.

In the step (3), the content of the boron-magnesium mineral powder in the aluminum-boron alkaline suspension is 5-50 g/L.

In the step (4), adding bottom water into the reaction kettle according to the amount of the bottom water in the reaction kettle, wherein the amount of the bottom water is 1/10-1/5 of the volume of the reaction kettle; the reaction temperature is 50-90 ℃; the adding speed of the aluminum sulfate solution is 20mL/min to 40 mL/min; controlling the pH value of the slurry obtained in the reaction kettle to be 8.5-9.5 by adjusting the flow rate of the aluminum boron alkaline suspension; the reaction time is 40-90 min.

In the step (5), after the reaction is finished, adding an ammonium sulfate solution into the reaction kettle to adjust the pH value of the slurry in the reaction kettle to 7.3-8.3; the aging condition is that the temperature is 80-90 ℃ and the time is 30-120 min.

In the step (5), washing is carried out by using deionized water with the temperature of 55-65 ℃ as washing water; the drying conditions are as follows: the temperature is 100-150 ℃ and the time is 6-10 hours.

The method of the invention has the following advantages:

(1) according to the method, the boron-magnesium mineral powder and the sodium metaaluminate solution are prepared into an aluminum-boron alkaline suspension, and the boron-magnesium mineral powder is used as a crystal nucleus of a parallel flow reaction, so that the prepared pseudo-boehmite crystal grains are adsorbed on the boron-magnesium mineral powder to grow up, and a larger pore volume and proper pore distribution are formed; the pseudo-boehmite prepared by the inventionRoasting for 3-6 hours at 500-700 ℃, wherein the obtained alumina has the following properties: the pore volume is 1.0-1.35 mL/g, the specific surface area is 300-380 m²(ii)/g; the pore distribution was as follows: the pore volume of pores with the pore diameter less than 6nm accounts for 4-8% of the total pore volume, the pore volume of pores with the pore diameter of 6-15 nm accounts for 65-80% of the total pore volume, and the pore volume of pores with the pore diameter more than 15nm accounts for 16-30% of the total pore volume. Boron content as B₂O₃Calculated as 3.0 percent to 15.0 percent. Compared with the prior art, the method has obvious technical effect.

(2) The method of the invention comprises the steps of adding ammonium sulfate solution to adjust the pH value to be alkalescent after the reaction is finished, and then aging at a higher temperature, wherein the ammonium sulfate reacts with the boron magnesium mineral powder to generate H₃BO₃The crystal is embedded into the pseudo-boehmite, so that the boron is not easy to lose.

(3) According to the method, the boron-magnesium mineral powder is used as a boron source for preparing the boron-containing pseudo-boehmite, and compared with the method for preparing the boron-containing pseudo-boehmite by using boric acid, boron is not easy to lose, so that the technical problem which is always desired to be solved in the field is solved; the method has low cost and easy operation, and solves the problem of low solubility of the boric acid.

(4) The method for preparing the boron-containing pseudo-boehmite has simple process, and the pore structure of the alumina obtained by roasting the prepared boron-containing pseudo-boehmite meets the requirement of a residual oil hydrogenation catalyst carrier.

(5) It is especially suitable for use as the carrier material of heavy fraction oil and residual oil hydrogenating catalyst, especially hydrogenating and decarbonizing catalyst.

Detailed Description

The technical features of the present invention will be further described by way of examples, but the present invention is not limited to the examples, and the percentages are by mass.

In the invention, the specific surface area, the pore volume and the pore distribution are measured by adopting a low-temperature liquid nitrogen adsorption method.