CN202376991U - Molecular sieve synthesis reaction kettle - Google Patents

Abstract

The utility model relates to a molecular sieve synthesis reaction kettle, which is characterized in that the reaction kettle is a jacket type reaction kettle, the bottom of the reaction kettle is spherical, a stirring paddle is arranged in the reaction kettle, a stirring shaft seal is double-end-face mechanical seal, two feed inlets, a safety valve and an emptying valve are arranged at the upper part of the reaction kettle, a discharge hole is arranged at the bottom, and a kettle bottom valve is arranged at the bottom of the reaction kettle; the stirring adopts three layers of combined stirring paddles at the upper part, the middle part and the lower part, and the lower part is a semi-anchor type stirring paddle. The molecular sieve synthesis reaction kettle has controllable temperature rising and falling speed and high temperature control precision; the materials are fully stirred and uniformly mixed, and the mass transfer and heat transfer effects are good; the solid content of the material is high (more than 55 percent), the dosage of the template agent can be saved, the crystallization speed is improved, and the cost of raw materials is reduced; the method has the advantages of more material feeding in a single kettle, high yield and capability of improving the production efficiency, and is particularly suitable for the reaction process of synthesizing the zeolite molecular sieve by a solid-like phase method.

Description

Molecular sieve synthesis reactor

technical field

The utility model belongs to the technical field of material production process equipment, in particular to a production equipment for synthesizing zeolite molecular sieves—a reactor.

technical background

There are three main synthesis methods of zeolite molecular sieves: traditional hydrothermal method, gas-solid phase method and quasi-solid phase method (also called wetting method). The gas-solid phase method is a new method for the synthesis of zeolite molecular sieves developed in the past ten years [Dong Jinxiang, Dong Ping. Technical progress in the synthesis of zeolites by vapor phase method [J] Petrochemical Industry, 1995, (03); Sun Xiuliang. Solid phase Theoretical calculation research on the synthesis of β molecular sieve and its synthesis mechanism [D] Beijing University of Chemical Technology, 2009]. The main difference from the traditional hydrothermal synthesis method is that the gas-solid phase method uses the silica-alumina gel containing an organic template as the solid phase. Then it crystallizes with water vapor to form zeolite. For example, Chen Tiehong and others used TEAOH as a template, water glass or silica sol as an alkali source, aluminum nitrate as an aluminum source, and sodium hydroxide as an alkali source to synthesize zeolite beta by a gas-solid phase method. The method is: add a certain amount of water glass into the reaction kettle, add sodium hydroxide solution and organic ammonium template agent during stirring, then add aluminum nitrate and water, stir until dry at an appropriate temperature, and make silica-alumina gel containing TEAOH Glue; put the dry silica-alumina gel in a self-made porous screen and put it in another stainless steel reaction kettle with a certain amount of water at the bottom of the kettle, seal it and place it in an oven; the gel generates its own pressure in the reaction kettle Under the action of water vapor, crystallize at 170°C for 5 days; the crystallized product is dried in the air after washing. A solid-phase synthesis method, the specific method is to use organic ammonium salt (such as TEAOH) as a template, solid coarse-pore silica gel as a silicon source, sodium aluminate as an aluminum source, and sodium hydroxide as an alkali source. First, add a certain amount of organic ammonium salt, NaOH (solid) and NaAlO2 (solid) into water and stir, heat, and dissolve to prepare a working lye; add a certain amount of coarse-pore silica gel to the reaction kettle, and add the prepared Working lye, then vigorously stir evenly; heat up after sealing the lid of the kettle, stir continuously at a certain speed, and crystallize at 120°C-170°C for 2-3d; the crystallized product is dried in the air after washing. Compared with the traditional hydrothermal synthesis method, the quasi-solid-phase synthesis method can not only reduce the amount of template agent, but also accelerate the crystallization rate and increase the single-pot yield.

CN200720173192.1 discloses a molecular sieve synthesis rotary reaction kettle system, including an electric heating blower box (1), a reaction kettle (2), rotating parts (4), control parts (6), etc., and the electric heating blower box (1) is equipped with The reaction kettle support (3), the reaction kettle (2) is fixedly connected with the reaction kettle support (3), the outer support frame (5) is connected with the rotating part (4), and a control part ( 6), the reaction is evenly mixed, easy to operate, easy to control, simple equipment structure, high efficiency, no leakage, reaction temperature, pressure, and rotation frequency can be adjusted, and several molecular sieves with different formulations can be synthesized under the same reaction conditions at one time. Several molecular sieves with the same formula and different reaction conditions can be synthesized at one time, so the application of this system to synthesize molecular sieves can save raw materials, shorten test time, improve work efficiency, and ensure the repeatability of synthetic molecular sieves.

CN200710172524.9 discloses a method for preparing molecular sieves in a horizontal reactor. The horizontal reactor is suitable for hydrothermal method or sol-gel method and other molecular sieve synthesis methods involving liquid and solid mixed systems, and can be used to synthesize various microporous molecular sieves, mesoporous molecular sieves and microporous-mesoporous composite molecular sieves. The invention overcomes the disadvantages of poor liquid-solid phase mixing effect and difficult control of the pore structure, particle size and particle size distribution of the obtained product in the synthesis of molecular sieves in a vertical reactor. The stirring blade of the horizontal reactor is a deformed turbine blade, the ratio of the diameter of the stirring blade to the inner diameter of the reactor is 0.4-0.85, and the ratio of the axial width of the stirring blade to the length of the kettle body is 0.11-0.35.

Different synthetic methods are suitable for different production equipment. The traditional hydrothermal method uses the pressure kettle as the crystallization reactor for static or dynamic crystallization; the gas-solid phase method uses the pressure kettle as the crystallization reactor for static crystallization; the solid-phase synthesis method uses the pressure kettle as the crystallization reactor , dynamic crystallization requires special stirring.

Utility model content

The purpose of the utility model is to provide a molecular sieve synthesis reaction kettle, especially a synthesis reaction device suitable for synthesizing zeolite molecular sieves by a solid-phase method, which can save production time and increase the yield of a single kettle.

In order to achieve the above object, the molecular sieve synthesis reactor of the present utility model is characterized in that the reactor is a jacketed reactor, the bottom of the reactor is spherical, and the stirring paddle is arranged inside, the stirring shaft seal is a double-end mechanical seal, and the upper part of the reactor has two There are two feed inlets, a safety valve and a vent valve, and a discharge outlet at the bottom with a tank bottom valve; the upper, middle and lower three-layer combined stirring paddles are used for stirring, and the lower part is a semi-anchor stirring paddle.

The upper and middle paddles can be typical solid-liquid suspension paddles, such as straight blade paddles, inclined blade paddles, folded blade paddles, double folded blade paddles, four-blade paddle opening, six-blade paddles, etc. , in order to prevent blade sticking, the blade cross section is preferably triangular. The shape of the upper stirring paddle and the middle stirring paddle can be the same, and it is better to add a scraping board at the blade end, which can be one or more pieces.

In order to reduce material hanging on the wall and facilitate cleaning, it is best to polish the inner wall of the kettle, the surface of the stirring shaft and the stirring paddle.

Generally, one of the two feed ports is a liquid feed port and the other is a solid feed port. The liquid feed line extends above the material surface in the kettle, and a nozzle is installed at the end.

The jacket is generally heated and cooled by heat conduction oil.

The lower part of the three-layer composite paddle is a semi-anchor paddle, and the gap between the paddle and the bottom is preferably 10-30mm.

The characteristics of the process for synthesizing zeolite molecular sieves by the solid phase method are: the reaction temperature is 140-180 °C, the reaction pressure is 1.0-2.0 MPa, and the solid content of the material can be greater than 55% (basically solid phase). The property change of the material during the reaction process is divided into three stages. In the initial stage, the material (silica gel) is a wet solid, non-viscous and easy to stir; as the temperature increases and the reaction time prolongs, the viscosity of the material increases. Stirring resistance is high, so a larger stirring power is required at this time, and at the same time, in order not to damage the crystal growth, the stirring speed needs to be strictly controlled; at the end of the reaction, a molecular sieve slurry (Bingham thixotropic fluid) is obtained, as long as the stirring is not stopped during the process If it is over, it is easy to stir, and the stirring power can be smaller at this time. The difference between it and the traditional hydrothermal process is that the solid content of the material is high, and it is difficult to mix evenly. The problems of mass transfer and heat transfer are the main problems in realizing this process.

According to the characteristics of material property changes during the reaction process of the above-mentioned solid-phase synthesis of zeolite molecular sieve, it is obviously not suitable to use the traditional hydrothermal synthesis kettle as the crystallization reactor, because the solid content of the material is generally not more than 20%, and the material is slurry, liquid Phase mixing and solid phase mixing have different requirements on the shape and structure of the agitator. Therefore, the utility model provides a reaction kettle for synthesizing molecular sieves, which can realize the production of zeolite molecular sieves synthesized by a solid-phase method.

The lye feed pump, heating system and control system should also be used in conjunction with the molecular sieve synthesis reactor. The heating system can choose a cold and hot machine.

The scraper plate 7 of the lower anchor paddle I and the upper paddle III fully considers that the solid material is fully mixed at the initial stage, basically there is no dead angle, and the liquid is evenly sprayed from the upper feed port to the solid surface, and the material is stirred by stirring. The solid-liquid two-phase materials are evenly mixed. For powders with fine particle size, low adhesion and certain jet flow, when the stirring speed increases to a certain level, a large amount of gas will be brought into the powder by the stirring impeller, or stirred in the powder. A hole is formed to make the impeller idle, so install a semi-anchor stirring paddle I at the lower part, and it is better to install a scraper 7 at the blade end of the upper part of the agitator, which can destroy the air bubbles in the powder. The stirring speed should not be too high in actual use. , the upper blade end scraper 7 is detachable, in the process of use, according to the properties of the material, if the mixing effect can be achieved, it can not be installed.

Compared with the traditional hydrothermal technology, the utility model has the following advantages: the heating and cooling speed is controllable, the temperature control precision is high; the material is fully stirred, evenly mixed, and the mass transfer and heat transfer effects are good; the solid content of the material is high (can be greater than 55 %), which can save the amount of template agent, increase the crystallization speed, and reduce the cost of raw materials; the single kettle has more materials and high yield, which can improve production efficiency.

Description of drawings

Figure 1 is a schematic diagram of a molecular sieve synthesis reactor.

Marked in the figure: 1. Semi-anchor stirring paddle I, 2. Set screw, 3. Key, 4. Stirring paddle II, 5. Stirring shaft, 6. Stirring paddle III, 7. Scraper plate, 8. Pin .

Figure 2 is a schematic diagram of the paddle II.

Fig. 3 is a schematic cross-sectional view of the stirring paddle II.

Figure 4 is a schematic diagram of a complete system of a synthetic zeolite molecular sieve device, marked as: A. Alkaline metering and feeding system, B. Molecular sieve crystallization kettle system, C. Cooling and heating integrated machine system.

Detailed ways

The specific implementation of the utility model, such as the shape, structure, interaction between each part, working principle, manufacturing process and operation and use method of the various components involved, will be further described below with reference to the accompanying drawings.

A is the lye metering and feeding system, B is the molecular sieve crystallization kettle system, and C is the cooling and heating integrated machine system composed of three parts (see Figure 4). Since the lye metering and feeding system, the pressure kettle and the integrated cooling and heating system are similar to the conventional technology, no special instructions are given.

Example:

Reactor: pressure 2.5MPa, temperature 200°C, V=55L, built-in stirring paddle, stirring speed 30-150r/min, motor power 4.0KW (stirring motor with frequency converter). Heat conduction oil is passed through the jacket of the equipment for heating or cooling.

There are two temperature measuring points, upper and middle, in the axial direction of the kettle, and two temperature control points are set on the wall of the kettle. There is a liquid feed port and a solid feed port on the upper part of the kettle. The liquid feed line extends above the material level in the kettle, and a nozzle is installed at the end. There is a discharge port at the bottom, equipped with a bottom valve, and there must be no material accumulation on the upper part of the valve. The upper part of the kettle is equipped with a safety valve and a vent valve.

Stirring system described in the utility model (see Fig. 1) adopts three layers of combined stirring paddles, the bottom is a semi-anchor type stirring paddle 1, and the ellipse bottom gap 20mm. The middle paddle II is a typical solid-liquid suspension paddle (4 paddles, see Figure 2). In order to prevent blade sticking, the blade section is triangular (see Figure 3). The upper impeller III is the same as the middle impeller II, except that two scraper boards are added at the blade end, the length is 170mm, the width is 30mm, and the distance from the kettle wall is 10mm.

The combined stirring paddle fully considers the initial mixing stage of the solid powder and the stirring state of the high-viscosity paste material stage in the reaction. In the stage of high-viscosity paste material in the reaction, the focus of stirring is how to obtain the required mixing effect with the minimum energy consumption. In this stage, the middle paddle II and the upper paddle III are combined, which has a good mixing ability. Compared with using a 45° four-bladed pitched propeller, when the same mixing effect is achieved, energy can be saved by about 50%.

The blade end of the impeller of the middle impeller II is narrow, which can reduce the impact and damage the crystallization. The axial flow impeller is the main one, which strengthens the axial mixing and facilitates the uniformity of temperature and concentration. The wall scraper 7 can scrape off the material from the kettle wall in time, preventing the material from sticking to the wall and avoiding uneven temperature of the material.

The working process of the utility model is: put the solid material into the kettle from the upper feeding port, pump the liquid material into the solid material in the kettle, turn on the stirring device, after fully stirring, start the cooling and heating integrated machine system, and heat to the set point. Set the temperature, start the reaction, continue to stir, after the reaction is over, cool down to the set temperature, and discharge the material from the outlet of the lower part of the kettle, that is, the working process of molecular sieve crystallization production is completed.

Claims (7)

1. A molecular sieve synthesis reactor, characterized in that the reactor is a jacketed reactor, the bottom of the reactor is spherical, with stirring paddles inside, the stirring shaft seal is a double-end mechanical seal, and the top of the still has two feed ports and Safety valve and vent valve, the lower part is equipped with a discharge port and a tank bottom valve; the stirring adopts the upper, middle and lower three-layer combined stirring paddle, and the lower part is a semi-anchor type stirring paddle. 2. The molecular sieve synthesis reactor according to claim 1, characterized in that the upper stirring paddle or the middle stirring paddle is a solid-liquid suspension stirring paddle. 3. The molecular sieve synthesis reaction kettle according to claim 1, characterized in that the upper stirring paddle or the middle stirring paddle is a straight blade type paddle, inclined blade type paddle, folded blade type paddle, double folded blade type paddle, four inclined blades paddles or six-blade paddles. 4. The molecular sieve synthesis reaction kettle according to claim 1, characterized in that the gap between the semi-anchor stirring paddle at the lower part of the three-layer combined stirring paddle and the bottom of the reactor is 10-30mm. 5. The molecular sieve synthesis reactor according to claim 1, characterized in that a scraper (7) is installed at the top of the three-layer combined stirring paddle at the blade end of the stirrer. 6. The molecular sieve synthesis reactor according to claim 1, characterized in that in the two feed ports, one is a liquid feed port and the other is a solid feed port, and the liquid feed line extends above the material level in the kettle , Install the nozzle at the end. 7. The molecular sieve synthesis reaction kettle according to claim 1, characterized in that the cross section of the central stirring blade is triangular. the

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