阅读说明：本技术 一种颗粒状低硅13x分子筛及其制备方法与应用 (Granular low-silicon 13X molecular sieve and preparation method and application thereof ) 是由 陈伟 王鹏飞 周永贤 陈诚 李豫晨 徐华胜 文雅 温玺 于 2020-10-30 设计创作，主要内容包括：本发明涉及一种颗粒状低硅13X分子筛及其制备方法与应用,制备方法包括以下步骤：1)成型：将常硅13X分子筛、无机粘结剂及造孔剂混合后成型,后经干燥、焙烧,得到颗粒状13X分子筛；2)碱转化：利用硅酸钠的碱性溶液对颗粒状13X分子进行碱处理,后经液固分离、干燥,得到碱处理后的颗粒状13X分子筛；3)铝化：将碱处理后的颗粒状13X分子筛浸入至高碱度铝酸钠溶液中进行转化处理,后经洗涤、干燥、活化即可。与现有技术相比,本发明以市售价廉的常硅13X分子筛为基体,经过碱转化和铝化,制备出CO_2吸附容量更高且强度较好的低粘结剂型颗粒状低硅13X分子筛,制备工艺更简单稳定且成本更低,得到的产品特别适用于深冷空分中CO_2杂质的高效脱除。(The invention relates to a granular low-silicon 13X molecular sieve and a preparation method and application thereof, wherein the preparation method comprises the following steps: 1) molding: mixing and forming a silicon-13X molecular sieve, an inorganic binder and a pore-forming agent, and then drying and roasting to obtain a granular 13X molecular sieve; 2) alkali conversion: carrying out alkali treatment on granular 13X molecules by using an alkaline solution of sodium silicate, and then carrying out liquid-solid separation and drying to obtain an alkali-treated granular 13X molecular sieve; 3) aluminizing: and (3) immersing the granular 13X molecular sieve subjected to alkali treatment into a high-alkalinity sodium aluminate solution for conversion treatment, and then washing, drying and activating the solution. Compared with the prior art, the method takes the cheap ordinary silicon 13X molecular sieve sold in the market as the matrix, and prepares CO through alkali conversion and aluminization 2 Low-binder granular low-silicon 1 with higher adsorption capacity and better strengthThe 3X molecular sieve has simpler and more stable preparation process and lower cost, and the obtained product is particularly suitable for CO in cryogenic air separation 2 And (4) efficiently removing impurities.)

1. A method for preparing a granular low-silicon 13X molecular sieve is characterized by comprising the following steps:

1) molding: mixing and forming a silicon-13X molecular sieve, an inorganic binder and a pore-forming agent, and then drying and roasting to obtain a granular 13X molecular sieve;

2) alkali conversion: carrying out alkali treatment on granular 13X molecules by using an alkaline solution of sodium silicate, and then carrying out liquid-solid separation and drying to obtain an alkali-treated granular 13X molecular sieve;

3) aluminizing: and (3) immersing the granular 13X molecular sieve subjected to alkali treatment into a high-alkalinity sodium aluminate solution for conversion treatment, and then washing, drying and activating to obtain the granular low-silicon 13X molecular sieve.

2. The method for preparing the granular low-silicon 13X molecular sieve according to claim 1, wherein in the step 1), the silicon-aluminum ratio of the normal-silicon 13X molecular sieve is 2.40-2.80; in the step 3), the silicon-aluminum ratio of the granular low-silicon 13X molecular sieve is 2.00-2.10.

3. The method of claim 1, wherein in step 1), the inorganic binder is a clay-based binder, and the pore-forming agent comprises one or more of methylcellulose, carboxymethylcellulose, maltodextrin, or corn starch; the mass ratio of the ordinary silicon 13X molecular sieve to the inorganic binder is (50-90) to (10-50), and the mass of the pore-forming agent is 1-10% of the total mass of the ordinary silicon 13X molecular sieve and the inorganic binder.

4. The method for preparing the granular low-silicon 13X molecular sieve according to claim 1, wherein in the step 1), the molding is performed by extrusion molding or granulation molding; in the drying process, the temperature is 100-; in the roasting process, the temperature is 400-650 ℃, and the time is 1-6 h.

5. The method for preparing the granular low-silicon 13X molecular sieve according to claim 1, wherein in the step 2), the alkaline solution of sodium silicate is a mixed aqueous solution of sodium silicate and sodium hydroxide, and the alkaline solution of sodium silicate contains 5-25% by mass of silicon oxide and 2-20% by mass of sodium oxide; according to the solid-liquid mass ratio of 1 (1-50), the granular 13X molecular sieve is immersed into an alkaline solution of sodium silicate.

6. The method for preparing the granular low-silicon 13X molecular sieve according to claim 1, wherein in the step 2), the dynamic alkali treatment is carried out under the condition of continuous feeding of a pump, the temperature is 80-100 ℃, and the time is 2-36 h; in the drying process, the temperature is 100-150 ℃, and the time is 2-36 h.

7. The method for preparing the granular low-silicon 13X molecular sieve according to claim 1, wherein in the step 3), the mass percentage of sodium aluminate in the high-alkalinity sodium aluminate solution is 5-35%; according to the solid-liquid mass ratio of 1 (1-20), immersing the granular 13X molecular sieve subjected to alkali treatment into a high-alkalinity sodium aluminate solution.

8. The method for preparing the granular low-silicon 13X molecular sieve according to claim 1, wherein in the step 3), the conversion treatment is carried out under continuous stirring at a temperature of 80-120 ℃ for 4-48 h; washing until the pH value is 9-10; in the drying process, the temperature is 120-; the activation is carried out under the protection of vacuum or inert gas, the activation temperature is 300-550 ℃, and the activation time is 2-8 h.

9. A particulate low silicon 13X molecular sieve, characterized in that it is prepared by a process according to any one of claims 1 to 8.

10. Use of the particulate low-silicon 13X molecular sieve of claim 9 as an adsorbent for CO in cryogenic air separation₂And (4) efficiently removing impurities.

Technical Field

The invention belongs to the technical field of inorganic material molecular sieves, and relates to a granular low-silicon 13X molecular sieve and a preparation method and application thereof.

Background

In the field of cryogenic air separation, granular 13X molecular sieve adsorbent is generally used industrially for CO in air₂Removal is carried out, in particular low-silicon 13X molecular sieves. The existing preparation method of the granular low-silicon 13X molecular sieve is a mature technology that raw powder of the low-silicon 13X molecular sieve is synthesized first and then a finished product of the granular low-silicon 13X molecular sieve is obtained by molding. However, the particulate low-silicon 13X molecular sieve produced by this method has an inorganic binder content of greater than 10 wt%, and higher levels of inorganic binder limit CO₂And (4) improving the adsorption performance. On the other hand, the granular low-silicon 13X molecular sieve used for industrial application must have sufficient crushing strength, but when the existing process is used to prepare the granular low-silicon 13X molecular sieve, if the content of the inorganic binder is reduced, the strength is remarkably reduced, and the industrial application cannot be satisfied.

At present, the granular low-silicon 13X molecular sieve prepared by the process on the market has static CO at 2.5mmHg (0 ℃)₂The adsorption capacity is 6.0-6.5 wt%; static CO at 250mmHg (0 deg.C)₂The adsorption capacity is 18.0-21.0 wt%. In addition, the process involves cumbersome powder divisionThe separation and washing process not only has complex operation but also generates a large amount of waste water, and the preparation cost is higher.

In recent years, with rapid development and technical innovation of air separation industry, CO of existing granular low-silicon 13X molecular sieve products₂The adsorption capacity gradually does not meet the more demanding technical requirements. Therefore, there is a need to develop new methods for preparing higher CO₂The granular low-silicon 13X molecular sieve has better adsorption capacity and strength.

Disclosure of Invention

The invention aims to provide a granular low-silicon 13X molecular sieve and a preparation method and application thereof. The invention takes the commercial cheap ordinary silicon 13X molecular sieve with the silicon-aluminum ratio of 2.40-3.00 as a matrix to prepare CO by alkali conversion and aluminizing₂The process method has the advantages of simple and convenient operation, good stability and repeatability, low cost and easy realization of industrialization.

The purpose of the invention can be realized by the following technical scheme:

a method for preparing a granular low-silicon 13X molecular sieve, the method comprising the steps of:

1) molding: mixing and forming a silicon-13X molecular sieve, an inorganic binder and a pore-forming agent, and then drying and roasting to obtain a granular 13X molecular sieve;

2) alkali conversion: carrying out alkali treatment on granular 13X molecules by using an alkaline solution of sodium silicate, and then carrying out liquid-solid separation and drying to obtain an alkali-treated granular 13X molecular sieve;

3) aluminizing: and (3) immersing the granular 13X molecular sieve subjected to alkali treatment into a high-alkalinity sodium aluminate solution for conversion treatment, and then washing, drying and activating to obtain the granular low-silicon 13X molecular sieve.

Further, in the step 1), the silicon-aluminum ratio of the normal silicon 13X molecular sieve is 2.40-2.80; in the step 3), the silicon-aluminum ratio of the granular low-silicon 13X molecular sieve is 2.00-2.10.

Preferably, the silicon to aluminum ratio of the conventional silicon 13X molecular sieve is 2.40 to 2.60.

Further, in step 1), the inorganic binder is a clay-based binder, and the pore-forming agent includes one or more of methyl cellulose, carboxymethyl cellulose, maltodextrin or corn starch; the mass ratio of the ordinary silicon 13X molecular sieve to the inorganic binder is (50-90) to (10-50), and the mass of the pore-forming agent is 1-10% of the total mass of the ordinary silicon 13X molecular sieve and the inorganic binder. Wherein, the mass ratio of the ordinary silicon 13X molecular sieve to the inorganic binder is preferably (65-90): 10-35), and the mass of the pore-forming agent is preferably 1-5% of the total mass of the ordinary silicon 13X molecular sieve and the inorganic binder.

Preferably, the clay-based binder comprises one or more of kaolin, montmorillonite, bentonite, diatomaceous earth, attapulgite, nacrite, dickite, or halloysite. The clay-based binder is more preferably a clay convertible into a molecular sieve structure, such as kaolin, montmorillonite, bentonite, nacrite, dickite, halloysite, and the like. In particular, kaolin calcined at 700-900 ℃ is preferred, the SiO of which₂40-50 wt% of Al₂O₃Content is more than or equal to 35 wt%, Fe₂O₃The content is less than 0.50 wt%.

Further, in the step 1), the molding adopts extrusion molding or granulation molding; in the drying process, the temperature is 100-; in the roasting process, the temperature is 400-650 ℃, and the time is 1-6 h. When extrusion molding is used, the granular 13X molecular sieve preferably has a strip shape with a diameter of 1.5-3.3mm and a length of 2.0-6.0 mm. When granulation molding is used, the size of the granular 13X molecular sieve is preferably spherical with a diameter of 1.6-2.5 mm.

Further, in the step 2), the alkaline solution of sodium silicate is a mixed aqueous solution of sodium silicate and sodium hydroxide, and in the alkaline solution of sodium silicate, the mass percentage of silicon oxide is 5-25%, and the mass percentage of sodium oxide is 2-20%; according to the solid-liquid mass ratio of 1 (1-50), immersing the granular 13X molecular sieve subjected to alkali treatment into an alkaline solution of sodium silicate.

Preferably, in the alkaline solution of sodium silicate, the mass percent of silicon oxide is 5-12%, and the mass percent of sodium oxide is 5-15%; the solid-liquid mass ratio is preferably 1 (1-20).

Further, in the step 2), dynamic alkali treatment under continuous feeding of a pump is adopted in the alkali treatment process, the temperature is 80-100 ℃, and the time is 2-36 hours; in the drying process, the temperature is 100-150 ℃, and the time is 2-36 h. Wherein, the alkali treatment temperature is preferably 85-95 ℃, and the continuous feeding time is preferably 14-24 h. The alkali treatment mode adopts dynamic alkali treatment under pump continuous feeding, on one hand, the driving force caused by concentration difference can be increased to promote the inorganic binder to be converted into the 13X molecular sieve, on the other hand, the crushing and pulverization phenomena of particles in the crystal conversion process can be avoided, and the integrity of the particles is ensured.

Further, in the step 3), the mass percentage of sodium aluminate in the high alkalinity sodium aluminate solution is 5-35%; according to the solid-liquid mass ratio of 1 (1-20), immersing the granular 13X molecular sieve subjected to alkali treatment into a high-alkalinity sodium aluminate solution.

Preferably, the high alkalinity sodium aluminate solution is prepared by dissolving solid sodium aluminate or aluminum hydroxide in a high concentration sodium hydroxide aqueous solution, wherein the content of sodium hydroxide in the high concentration sodium hydroxide aqueous solution is 30.0-80.0 wt%; in the high alkalinity sodium aluminate solution, the mass percentage of the sodium aluminate is preferably 10-30%; the solid-liquid mass ratio is preferably 1 (1-10).

Further, in the step 3), the conversion treatment process is carried out under continuous stirring at the temperature of 80-120 ℃ for 4-48 h; washing until the pH value is 9-10; in the drying process, the temperature is 120-; the activation is carried out under the protection of vacuum or inert gas, the activation temperature is 300-550 ℃, and the activation time is 2-8 h.

Preferably, the conversion treatment process is as follows: continuously stirring for 6-12h at 90-95 ℃.

The granular low-silicon 13X molecular sieve is prepared by adopting the method. The prepared granular low-silicon 13X molecular sieve has smooth surface, no obvious powder falling phenomenon, good crushing strength and high CO content₂Adsorption capacity.

Application of granular low-silicon 13X molecular sieve as adsorbent for adsorbingCO in cryogenic air separation₂And (4) efficiently removing impurities.

In the granular low-silicon 13X molecular sieve product prepared by the invention, the silicon-aluminum ratio is 2.00-2.10, the content of the inorganic binder is less than 5.0 wt%, and the product has better crushing strength and higher CO₂Adsorption capacity. 2.5mmHg (0 deg.C), static CO₂The adsorption capacity is more than or equal to 7.0 wt%; static CO at 250mmHg (0 deg.C)₂The adsorption capacity is more than or equal to 22.0 wt%. The invention takes the ordinary silicon 13X molecular sieve powder as the raw material to carry out aluminum supplement conversion to obtain the granular low-silicon 13X molecular sieve with low adhesive, the preparation process is simpler and more stable, the cost is lower, and the obtained product is particularly suitable for CO in cryogenic air separation₂And (4) efficiently removing impurities.

Compared with the prior art, the invention has the following characteristics:

1) different from the existing method for preparing the low-silicon 13X molecular sieve raw powder and then forming, the invention adopts a process of forming firstly and then converting. The low-silicon granular 13X molecular sieve is prepared by using cheap ordinary silicon 13X molecular sieve and inorganic binder as raw materials, forming to obtain granular ordinary silicon 13X molecular sieve, and then using the granules as a matrix, and performing alkali liquor treatment and sodium aluminate solution conversion. The whole process completely avoids complicated powder filtering and washing, the solid-liquid separation is simpler and more convenient, the energy consumption is lower, no waste water is discharged, and the performance of the obtained product is more stable.

2) Compared with the existing granular low-silicon 13X molecular sieve, the granular low-silicon 13X molecular sieve prepared by the invention is of a low-binder type, and the content of the inorganic binder is less than 5.0 wt% and is far lower than that of the inorganic binder of 10-15 wt% of the common granular low-silicon 13X molecular sieve. In addition, the granular low-silicon 13X molecular sieve prepared by the invention still has better crushing strength and higher CO under the condition of lower content of the inorganic binder₂Adsorption capacity, and is more suitable for low partial pressure CO in the air separation field₂And (4) removing impurities.

3) The preparation process of the granular low-silicon 13X molecular sieve is simple and stable, the investment cost of the device at the early stage is low, and the industrialization is easy to realize.

Drawings

Fig. 1 is an XRD pattern of the granular low-silicon 13X molecular sieve prepared in example 1.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

Example 1:

a preparation method of a granular low-silicon 13X molecular sieve comprises the following steps:

molding: 50 parts of commercially available ordinary silicon 13X molecular sieve powder with the silicon-aluminum ratio of 2.40, 50 parts of montmorillonite and methylcellulose with the total mass of the 13X molecular sieve and the montmorillonite being 1 wt% are uniformly mixed, and the mixture is granulated and formed by a sugar coating machine after being sprayed with water, dried at 100 ℃ for 10 hours and roasted at 400 ℃ for 6 hours to obtain the ordinary silicon 13X molecular sieve balls with the particle size of 1.6-2.5 mm.

Alkali treatment: 440g of ordinary silicon 13X molecular sieve balls are filled in a fixed bed, and then an alkaline solution containing 5 wt% of sodium oxide and 20 wt% of silicon oxide is slowly introduced into the fixed bed for 36 hours at 80 ℃ according to the solid-to-liquid ratio of 1: 50. And separating particles after the alkali treatment is finished, and drying at 150 ℃ for 4h to obtain the low-binder ordinary silicon 13X molecular sieve balls.

Aluminizing: according to the using amount of a solid-to-liquid ratio of 1:10, 45g of low-binder type ordinary silicon 13X molecular sieve balls are placed in a 5 wt% high-alkalinity sodium aluminate solution, continuously stirred and converted for 48 hours at 80 ℃, washed until the pH value is 9-10, dried for 10 hours at 120 ℃ and activated for 4 hours in vacuum at 300 ℃ to obtain the low-silicon 13X molecular sieve balls.

Carrying out phase and CO treatment on the prepared low-silicon 13X molecular sieve balls₂The results of the adsorption performance analysis and the phase are shown in FIG. 1. The results show that the prepared granular low-silicon 13X molecular sieve is a pure-phase X molecular sieve crystal, the content of the inorganic binder in the granules is 2.8 wt%, the silicon-aluminum ratio is 2.05, and the crushing strength is 32N/granule. CO 2₂The adsorption performance results show that the static CO is 2.5mmHg (0℃)₂An adsorption capacity of 7.6 wt%, and static CO at 250mmHg (0 deg.C)₂The adsorption capacity was 22.2 wt%.

Example 2:

a preparation method of a granular low-silicon 13X molecular sieve comprises the following steps:

molding: 70 parts of commercially available ordinary silicon 13X molecular sieve powder with the silicon-aluminum ratio of 2.80, 30 parts of nacrite and methylcellulose with the total mass of the 13X molecular sieve and the nacrite being 10 wt% are uniformly mixed, and the mixture is sprayed with water to be granulated and formed by a sugar coating machine, dried at 180 ℃ for 2 hours and roasted at 650 ℃ for 1 hour to obtain the ordinary silicon 13X molecular sieve balls with the particle size of 1.6-2.5 mm.

Alkali treatment: 440g of ordinary silicon 13X molecular sieve balls are filled in a fixed bed, and then an alkaline solution containing 25 wt% of sodium oxide and 2 wt% of silicon oxide is slowly introduced into the fixed bed for 2 hours at 100 ℃ according to the solid-to-liquid ratio of 1: 5. And separating particles after the alkali treatment is finished, and drying at 120 ℃ for 4h to obtain the low-binder ordinary silicon 13X molecular sieve balls.

Aluminizing: according to the using amount of a solid-to-liquid ratio of 1:20, 45g of low-binder type ordinary silicon 13X molecular sieve balls are placed in a 5 wt% high-alkalinity sodium aluminate solution, continuously stirred and converted for 4 hours at 120 ℃, washed until the pH value is 9-10, dried for 2 hours at 180 ℃, and activated for 6 hours in vacuum at 350 ℃, so that the low-silicon 13X molecular sieve balls are obtained.

Analysis of the prepared low-silicon 13X molecular sieve ball shows that the inorganic binder content in the particles is 2.1 wt%, the silicon-aluminum ratio is 2.01, and the crushing strength is 33N/particle. CO 2₂The adsorption performance results show that the static CO is 2.5mmHg (0℃)₂An adsorption capacity of 7.2 wt%, and static CO at 250mmHg (0 deg.C)₂The adsorption capacity was 22.2 wt%.

Example 3:

a preparation method of a granular low-silicon 13X molecular sieve comprises the following steps:

molding: 85 parts of commercially available ordinary silicon 13X molecular sieve powder with the silicon-aluminum ratio of 2.40, 15 parts of goat-sweet soil and methylcellulose with the total mass of the 13X molecular sieve and the goat-sweet soil being 5 wt% are uniformly mixed, sprayed with water, granulated and formed by a sugar coating machine, dried at 180 ℃ for 4h and roasted at 650 ℃ for 1h to obtain the ordinary silicon 13X molecular sieve balls with the particle size of 1.5-2.4 mm.

Alkali treatment: 440g of ordinary silicon 13X molecular sieve balls are filled in a fixed bed, and then alkaline solution containing 15 wt% of sodium oxide and 10 wt% of silicon oxide is slowly introduced into the fixed bed for 2 hours at 95 ℃ according to the solid-to-liquid ratio of 1: 30. And separating particles after the alkali treatment is finished, and drying at 160 ℃ for 4h to obtain the low-binder ordinary silicon 13X molecular sieve balls.

Aluminizing: according to the using amount of a solid-to-liquid ratio of 1:50, 45g of low-binder type ordinary silicon 13X molecular sieve balls are placed in a 5 wt% high-alkalinity sodium aluminate solution, continuously stirred and converted for 4 hours at 120 ℃, washed until the pH value is 9-10, dried for 2 hours at 180 ℃, and activated for 4 hours in vacuum at 400 ℃ to obtain the low-silicon 13X molecular sieve balls.

Analysis of the prepared low-silicon 13X molecular sieve ball shows that the inorganic binder content in the particles is 4.2 wt%, the silicon-aluminum ratio is 2.05, and the crushing strength is 28N/particle. CO 2₂The adsorption performance results show that the static CO is 2.5mmHg (0℃)₂An adsorption capacity of 7.2 wt%, and static CO at 250mmHg (0 deg.C)₂The adsorption capacity was 22.5 wt%.

Example 4:

a preparation method of a granular low-silicon 13X molecular sieve comprises the following steps:

molding: 85 parts of commercial ordinary silicon 13X molecular sieve powder with the silicon-aluminum ratio of 2.40, 15 parts of kaolin, methylcellulose with the total mass of the 13X molecular sieve and the kaolin being 5 wt% and a proper amount of water are uniformly mixed, and the ordinary silicon 13X molecular sieve strip with the diameter of 1.5-1.7mm and the length of 3.0-6.0mm can be obtained by extrusion molding, drying at 150 ℃ for 6h and roasting at 550 ℃ for 2 h.

Alkali treatment: 440g of ordinary silicon 13X molecular sieve balls are filled in a fixed bed, and then alkaline solution containing 8 wt% of sodium oxide and 15 wt% of silicon oxide is slowly introduced into the fixed bed for 24 hours at 95 ℃ according to the solid-to-liquid ratio of 1: 15. And separating particles after the alkali treatment is finished, and drying at 160 ℃ for 4h to obtain the low-binder type ordinary silicon 13X molecular sieve strip.

Aluminizing: according to the using amount of a solid-to-liquid ratio of 1:50, 45g of low-binder type ordinary silicon 13X molecular sieve balls are placed in a 5 wt% high-alkalinity sodium aluminate solution, continuously stirred and converted for 12h at 95 ℃, washed until the pH value is 9-10, dried for 6h at 150 ℃ and activated for 4h in vacuum at 350 ℃, and the strip-shaped low-silicon 13X molecular sieve is obtained.

For the prepared stripAnalysis of the low-silicon 13X molecular sieve shows that the inorganic binder content in the particles is 3.8 wt%, the silica-alumina ratio is 2.07, and the crushing strength is 35N/particle. CO 2₂The adsorption performance results show that the static CO is 2.5mmHg (0℃)₂An adsorption capacity of 7.4 wt%, and static CO at 250mmHg (0 deg.C)₂The adsorption capacity was 22.5 wt%.

Example 5:

a preparation method of a granular low-silicon 13X molecular sieve comprises the following steps:

molding: 65 parts of commercial ordinary silicon 13X molecular sieve powder with the silicon-aluminum ratio of 2.40, 35 parts of dickite, methylcellulose accounting for 5 wt% of the total mass of the 13X molecular sieve and the dickite and a proper amount of water are uniformly mixed, and the ordinary silicon 13X molecular sieve strip with the diameter of 3.0-3.3mm and the length of 4.0-6.0mm can be obtained by extrusion molding, drying at 150 ℃ for 6h and roasting at 600 ℃ for 2 h.

Alkali treatment: 440g of ordinary silicon 13X molecular sieve balls are filled in a fixed bed, and then alkaline solution containing 6 wt% of sodium oxide and 10 wt% of silicon oxide is slowly introduced into the fixed bed for 20 hours at 95 ℃ according to the solid-to-liquid ratio of 1: 40. And separating particles after the alkali treatment is finished, and drying at 160 ℃ for 4h to obtain the low-binder type ordinary silicon 13X molecular sieve strip.

Aluminizing: according to the using amount of a solid-to-liquid ratio of 1:50, 45g of low-binder type ordinary silicon 13X molecular sieve balls are placed in a 5 wt% high-alkalinity sodium aluminate solution, continuously stirred and converted for 10 hours at 100 ℃, washed until the pH value is 9-10, dried for 6 hours at 160 ℃, and activated for 4 hours in vacuum at 350 ℃, so that the strip-shaped low-silicon 13X molecular sieve is obtained.

Analysis of the prepared strip-shaped low-silicon 13X molecular sieve shows that the inorganic binder content in the particles is 2.5 wt%, the silicon-aluminum ratio is 2.08, and the average crushing strength is 45N/particle. CO 2₂The adsorption performance results show that the static CO is 2.5mmHg (0℃)₂An adsorption capacity of 7.4 wt%, and static CO at 250mmHg (0 deg.C)₂The adsorption capacity was 22.3 wt%.

Example 6:

a method for preparing a granular low-silicon 13X molecular sieve, the method comprising the steps of:

1) molding: mixing and forming a silicon-13X molecular sieve, an inorganic binder and a pore-forming agent, and then drying and roasting to obtain a granular 13X molecular sieve;

2) alkali conversion: carrying out alkali treatment on granular 13X molecules by using an alkaline solution of sodium silicate, and then carrying out liquid-solid separation and drying to obtain an alkali-treated granular 13X molecular sieve;

3) aluminizing: and (3) immersing the granular 13X molecular sieve subjected to alkali treatment into a high-alkalinity sodium aluminate solution for conversion treatment, and then washing, drying and activating to obtain the granular low-silicon 13X molecular sieve.

In the step 1), the silicon-aluminum ratio of the normal silicon 13X molecular sieve is 2.40. The inorganic binder is clay binder, and the pore-forming agent is carboxymethyl cellulose; the mass ratio of the ordinary silicon 13X molecular sieve to the inorganic binder is 90:10, and the mass of the pore-forming agent is 10% of the total mass of the ordinary silicon 13X molecular sieve and the inorganic binder.

The molding adopts extrusion molding or granulation molding; in the drying process, the temperature is 100 ℃, and the time is 24 hours; in the roasting process, the temperature is 400 ℃ and the time is 6 hours.

In the step 2), the alkaline solution of sodium silicate is a mixed aqueous solution of sodium silicate and sodium hydroxide, and in the alkaline solution of sodium silicate, the mass percent of silicon oxide is 5%, and the mass percent of sodium oxide is 20%; according to the solid-liquid mass ratio of 1:1, a granular 13X molecular sieve is immersed into an alkaline solution of sodium silicate.

The alkali treatment process adopts dynamic alkali treatment under the condition of continuous feeding of a pump, the temperature is 100 ℃, and the time is 2 hours; in the drying process, the temperature is 150 ℃ and the time is 2 h.

In the step 3), the mass percentage of sodium aluminate in the high alkalinity sodium aluminate solution is 35%; according to the solid-liquid mass ratio of 1:1, immersing the granular 13X molecular sieve subjected to alkali treatment into a high-alkalinity sodium aluminate solution.

The conversion treatment process is carried out under continuous stirring, the temperature is 120 ℃, and the time is 4 hours; washing until the pH value is 10; in the drying process, the temperature is 120 ℃, and the time is 10 hours; the activation is carried out under the protection of vacuum or inert gas, the activation temperature is 300 ℃, and the activation time is 8 h.

The granular low-silicon 13X molecular sieve is used as an adsorbent,CO used in cryogenic air separation₂And (4) efficiently removing impurities.

Example 7:

a method for preparing a granular low-silicon 13X molecular sieve, the method comprising the steps of:

1) molding: mixing and forming a silicon-13X molecular sieve, an inorganic binder and a pore-forming agent, and then drying and roasting to obtain a granular 13X molecular sieve;

2) alkali conversion: carrying out alkali treatment on granular 13X molecules by using an alkaline solution of sodium silicate, and then carrying out liquid-solid separation and drying to obtain an alkali-treated granular 13X molecular sieve;

3) aluminizing: and (3) immersing the granular 13X molecular sieve subjected to alkali treatment into a high-alkalinity sodium aluminate solution for conversion treatment, and then washing, drying and activating to obtain the granular low-silicon 13X molecular sieve.

In the step 1), the silicon-aluminum ratio of the normal silicon 13X molecular sieve is 2.80. The inorganic binder is clay binder, and the pore-forming agent is maltodextrin; the mass ratio of the ordinary silicon 13X molecular sieve to the inorganic binder is 50:50, and the mass of the pore-forming agent is 1% of the total mass of the ordinary silicon 13X molecular sieve and the inorganic binder.

The molding adopts extrusion molding or granulation molding; in the drying process, the temperature is 180 ℃ and the time is 1 h; in the roasting process, the temperature is 650 ℃ and the time is 1 h.

In the step 2), the alkaline solution of sodium silicate is a mixed aqueous solution of sodium silicate and sodium hydroxide, and in the alkaline solution of sodium silicate, the mass percent of silicon oxide is 25%, and the mass percent of sodium oxide is 2%; according to the solid-liquid mass ratio of 1:50, the granular 13X molecular sieve is immersed into an alkaline solution of sodium silicate.

The alkali treatment process adopts dynamic alkali treatment under the condition of continuous feeding of a pump, the temperature is 80 ℃, and the time is 36 hours; in the drying process, the temperature is 100 ℃ and the time is 36 h.

In the step 3), the mass percentage of sodium aluminate in the high alkalinity sodium aluminate solution is 5%; and (3) immersing the granular 13X molecular sieve subjected to alkali treatment into a high-alkalinity sodium aluminate solution according to the solid-liquid mass ratio of 1: 20.

The conversion treatment process is carried out under continuous stirring, the temperature is 80 ℃, and the time is 48 hours; washing until the pH value is 9; in the drying process, the temperature is 180 ℃ and the time is 2 hours; the activation is carried out under the protection of vacuum or inert gas, the activation temperature is 550 ℃, and the activation time is 2 h.

The granular low-silicon 13X molecular sieve is used as an adsorbent for CO in cryogenic air separation₂And (4) efficiently removing impurities.

Example 8:

a method for preparing a granular low-silicon 13X molecular sieve, the method comprising the steps of:

1) molding: mixing and forming a silicon-13X molecular sieve, an inorganic binder and a pore-forming agent, and then drying and roasting to obtain a granular 13X molecular sieve;

2) alkali conversion: carrying out alkali treatment on granular 13X molecules by using an alkaline solution of sodium silicate, and then carrying out liquid-solid separation and drying to obtain an alkali-treated granular 13X molecular sieve;

3) aluminizing: and (3) immersing the granular 13X molecular sieve subjected to alkali treatment into a high-alkalinity sodium aluminate solution for conversion treatment, and then washing, drying and activating to obtain the granular low-silicon 13X molecular sieve.

In the step 1), the silicon-aluminum ratio of the normal silicon 13X molecular sieve is 2.60. The inorganic binder is clay binder, and the pore-forming agent is corn starch; the mass ratio of the ordinary silicon 13X molecular sieve to the inorganic binder is 70:30, and the mass of the pore-forming agent is 5% of the total mass of the ordinary silicon 13X molecular sieve and the inorganic binder.

The molding adopts extrusion molding or granulation molding; in the drying process, the temperature is 140 ℃ and the time is 12 h; in the roasting process, the temperature is 500 ℃ and the time is 3 hours.

In the step 2), the alkaline solution of sodium silicate is a mixed aqueous solution of sodium silicate and sodium hydroxide, and in the alkaline solution of sodium silicate, the mass percent of silicon oxide is 15%, and the mass percent of sodium oxide is 12%; according to the solid-liquid mass ratio of 1:25, the granular 13X molecular sieve is immersed into an alkaline solution of sodium silicate.

The alkali treatment process adopts dynamic alkali treatment under the condition of continuous feeding of a pump, the temperature is 90 ℃, and the time is 18 hours; during the drying process, the temperature is 120 ℃ and the time is 18 h.

In the step 3), the mass percentage of sodium aluminate in the high alkalinity sodium aluminate solution is 20%; and (3) immersing the granular 13X molecular sieve subjected to alkali treatment into a high-alkalinity sodium aluminate solution according to the solid-liquid mass ratio of 1: 10.

The conversion treatment process is carried out under the condition of continuous stirring, the temperature is 100 ℃, and the time is 28 hours; washing until the pH value is 9.5; in the drying process, the temperature is 150 ℃ and the time is 5 hours; the activation is carried out under the protection of vacuum or inert gas, the activation temperature is 400 ℃, and the activation time is 5 hours.

The granular low-silicon 13X molecular sieve is used as an adsorbent for CO in cryogenic air separation₂And (4) efficiently removing impurities.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.