Method for preparing small-grain SAPO-34 molecular sieve

Abstract

The invention provides a method for preparing a small-grain SAPO-34 molecular sieve. The method comprises the following steps: 1) taking hectorite clay as a part of a silicon source; 2) putting dry glue prepared from an aluminum source, a phosphorus source and a silicon source at the upper part of a reaction kettle, putting a mixture of water and an organic template agent at the lower part of the reaction kettle, and conducting crystallizing for 4-48 hours at the crystallization temperature of 140-200 DEG C. and 3) washing, drying and calcining the product in the reaction kettle to obtain the SAPO-34 molecular sieves. The method solves the problems of complex synthesis process and high synthesis cost of the existing small-grain molecular sieves, and the synthesis efficiency is higher, and compared with the molecular sieves synthesized by conventional chemicals, the particle size of the prepared molecular sieves is obviously reduced.

Description

technical field

[0001] The invention relates to the technical field of molecular sieves and preparation thereof, in particular to a method for preparing small-grain SAPO-34 molecular sieves by using a dry glue conversion method. Background technique

[0002] As an important chemical raw material, low-carbon olefins (ethylene and propylene) are widely used in the production of various chemical industries. With the rapid development of my country's national economy, especially the development of modern chemical industry, the demand for low-carbon olefins is increasing day by day, and the contradiction between supply and demand will become increasingly prominent. As a non-oil pathway to produce light olefins from abundant carbon resources such as coal and natural gas, methanol-to-olefins (MTO) has attracted extensive attention from academia and industry. The key to MTO reaction lies in the choice of catalyst. Zeolite molecular sieves are an important class of shape-selective ...

Examples

Embodiment 1

[0021] Add 16.4 g of aluminum isopropoxide to 46 g of water and stir magnetically at room temperature for 3 h, add 8.5 g of phosphoric acid and continue stirring for 1 h, then add 14.5 g of hectorite gel with a mass fraction of 8% and stir for 1 h, and finally add 2.5 g tetraethyl orthosilicate, stirred for 3 h to form an initial gel. The gel was stirred at 80 ºC for 12 h to prepare dry gel, which was ground into powder. Take 7.0 g of dry glue and place it in the upper part of the reactor, and the lower part of the reactor is a mixed solution of 4.9 g of morpholine and 4.9 g of water, and crystallize the reactor at 180ºC for 36 h. After the reaction, the product was fully washed, filtered, dried in an oven at 100 ºC for 5 h, and calcined at 550 ºC for 8 h to obtain small-grained SAPO-34 molecular sieves.

Embodiment 2

[0027] Add 16.4 g of aluminum isopropoxide to 40 g of water and stir magnetically at room temperature for 3 h, add 8.5 g of phosphoric acid and continue stirring for 1 h, then add 19.2 g of laponite gel with a mass fraction of 8 wt% and stir for 1 h, and finally add 1.25 g of orthosilicon Acetate tetraethyl ester, stirred for 3 h to form an initial gel. The gel was stirred at 80 ºC for 12 h to prepare dry gel, which was ground into powder. Take 7.0 g of dry glue and place it in the upper part of the reactor, and the lower part of the reactor is a mixed solution of 4.9 g of morpholine and 4.9 g of water, and crystallize the reactor at 180ºC for 36 h. After the reaction, the product was fully washed, filtered, dried in an oven at 100 ºC for 5 h, and calcined at 550 ºC for 8 h to obtain small-grained SAPO-34 molecular sieves.

Embodiment 3

[0029]Add 16.4g of aluminum isopropoxide into 48g of water and stir magnetically at room temperature for 3h, add 8.5g of phosphoric acid and continue stirring for 1h, then add 9.6g of hectorite gel with a mass fraction of 8 wt% and stir for 1h, and finally add 3.75g of orthosilicon Acid tetraethyl ester, stirred for 3h to form an initial gel. The gel was stirred at 80 ºC for 12 h to prepare dry gel, which was ground into powder. Take 7.0g of dry glue and place it in the upper part of the reactor, and the lower part of the reactor is a mixed solution of 4.9 g of morpholine and 4.9 g of water, and crystallize the reactor at 180 ºC for 36 h. After the reaction, the product was fully washed, filtered, dried in an oven at 100 ºC for 5 h, and calcined at 550 ºC for 8 h to obtain small-grained SAPO-34 molecular sieves.

technical field

[0001] The invention relates to the technical field of molecular sieves and preparation thereof, in particular to a method for preparing small-grain SAPO-34 molecular sieves by using a dry glue conversion method. Background technique

[0002] As an important chemical raw material, low-carbon olefins (ethylene and propylene) are widely used in the production of various chemical industries. With the rapid development of my country's national economy, especially the development of modern chemical industry, the demand for low-carbon olefins is increasing day by day, and the contradiction between supply and demand will become increasingly prominent. As a non-oil pathway to produce light olefins from abundant carbon resources such as coal and natural gas, methanol-to-olefins (MTO) has attracted extensive attention from academia and industry. The key to MTO reaction lies in the choice of catalyst. Zeolite molecular sieves are an important class of shape-selective ...

Examples

Embodiment 1

[0021] Add 16.4 g of aluminum isopropoxide to 46 g of water and stir magnetically at room temperature for 3 h, add 8.5 g of phosphoric acid and continue stirring for 1 h, then add 14.5 g of hectorite gel with a mass fraction of 8% and stir for 1 h, and finally add 2.5 g tetraethyl orthosilicate, stirred for 3 h to form an initial gel. The gel was stirred at 80 ºC for 12 h to prepare dry gel, which was ground into powder. Take 7.0 g of dry glue and place it in the upper part of the reactor, and the lower part of the reactor is a mixed solution of 4.9 g of morpholine and 4.9 g of water, and crystallize the reactor at 180ºC for 36 h. After the reaction, the product was fully washed, filtered, dried in an oven at 100 ºC for 5 h, and calcined at 550 ºC for 8 h to obtain small-grained SAPO-34 molecular sieves.

Embodiment 2

[0027] Add 16.4 g of aluminum isopropoxide to 40 g of water and stir magnetically at room temperature for 3 h, add 8.5 g of phosphoric acid and continue stirring for 1 h, then add 19.2 g of laponite gel with a mass fraction of 8 wt% and stir for 1 h, and finally add 1.25 g of orthosilicon Acetate tetraethyl ester, stirred for 3 h to form an initial gel. The gel was stirred at 80 ºC for 12 h to prepare dry gel, which was ground into powder. Take 7.0 g of dry glue and place it in the upper part of the reactor, and the lower part of the reactor is a mixed solution of 4.9 g of morpholine and 4.9 g of water, and crystallize the reactor at 180ºC for 36 h. After the reaction, the product was fully washed, filtered, dried in an oven at 100 ºC for 5 h, and calcined at 550 ºC for 8 h to obtain small-grained SAPO-34 molecular sieves.

Embodiment 3

[0029]Add 16.4g of aluminum isopropoxide into 48g of water and stir magnetically at room temperature for 3h, add 8.5g of phosphoric acid and continue stirring for 1h, then add 9.6g of hectorite gel with a mass fraction of 8 wt% and stir for 1h, and finally add 3.75g of orthosilicon Acid tetraethyl ester, stirred for 3h to form an initial gel. The gel was stirred at 80 ºC for 12 h to prepare dry gel, which was ground into powder. Take 7.0g of dry glue and place it in the upper part of the reactor, and the lower part of the reactor is a mixed solution of 4.9 g of morpholine and 4.9 g of water, and crystallize the reactor at 180 ºC for 36 h. After the reaction, the product was fully washed, filtered, dried in an oven at 100 ºC for 5 h, and calcined at 550 ºC for 8 h to obtain small-grained SAPO-34 molecular sieves.

Images