Air inlet combination device of fluidized bed for organic silicon monomer synthesis and organic silicon fluidized bed

Abstract

The invention provides a distribution-plate-free gas inlet combination device for an organic silicon fluidized bed and the organic silicon fluidized bed. The air inlet combination device comprises a bottom center hole air inlet and side wall jet air inlet combination mode. The bottom center hole air inlet is arranged at the bottom of the fluidized bed lower cone, and the side wall jet air inlet is arranged on the side wall of the cone and the upper portion of the center hole. The organic silicon fluidized bed comprises a lower cone, a fluidized bed main body, an expansion section and a top upper sealing head. Chloromethane gas enters the cone from a center hole in the bottom and the injection pipe on the side wall and carries silicon powder particles to flow upwards to form spouted fluidization. And the silicon powder particles are taken out of the fluidized bed by the chloromethane gas from the top upper seal head to enter the cyclone separator. The fluidized bed is suitable for wide screening of silicon powder with particle size distribution, the problems that a distribution plate is blocked and a large amount of silicon powder is brought out are solved, abrasion of silicon powder particles to a heat exchange pipe is reduced, the surface updating of the silicon powder and the mixing efficiency of chloromethane gas and the silicon powder particles are improved, and therefore the monomer yield is increased, and online material pushing is achieved.

Description

Technical Field

[0001] The invention relates to an air intake mode of a fluidized bed for synthesizing organic silicon monomers, which is a combination of a distribution plate-free and side-swirl air intake, and an organic silicon fluidized bed. Background Art

[0002] The production of organosilicon materials is inseparable from methylchlorosilane monomers, among which dimethyldichlorosilane monomer (abbreviated as dimethyl) is the most important and largest-dosage basic raw material (accounting for 80% of the total monomers). At present, the synthesis of organosilicon monomers in industrial production is mainly completed in fluidized bed reactors. The performance of the fluidized bed has an important influence on the yield, monomer selectivity and conversion rate of organosilicon. Among them, the air inlet device is the core component of the organosilicon monomer fluidized bed, and plays an important role in the fluidization quality and stable operation in the fluidized bed. Large-scale organosilicon monomer fluidized beds generally use perforated gas distribution plates to fluidize materials, in which the orifice size and hole spacing affect the pressure drop of the distributor and the fluidization quality of solid phase particles. The particle size of the reactant silicon powder used in industrial production is a wide screening distribution, and its fluidization process is prone to produce particles of different particle sizes at different bed heights. Reasonable distribution plate structure design is crucial to ensure efficient fluidization of silicon powder and reduce particle separation. An unreasonable design of the gas distribution plate will cause uneven air distribution, forming bias flow and channel flow, and the pores are prone to leakage and blockage, thereby reducing the gas-solid mass transfer rate, and the heat released by the reaction is not removed in time, resulting in an increase in side reactions and affecting the yield. In response to the above problems, CN216630756U discloses a gas injection device for an upper and lower layer combination of an organic silicon fluidized bed reactor, which improves the uniformity of gas distribution in the bed and breaks up silicon powder agglomerates to promote catalyst surface renewal. CN110559955A discloses an organic silicon fluidized bed gas distributor, in which the distribution plate is evenly distributed with radial air inlets in the circumference, and the air inlets are located at the lower end surface of the hood, which can prevent leakage. CN113877489A discloses an air intake device combining a middle air intake and a side wall air intake, in which most of the chloromethane gas enters from the middle air intake pipe to produce jet fluidization, and a small part of the chloromethane gas enters from the side wall air intake pipe. The above-mentioned literature attempts to partially solve the problems of leakage and uneven fluidization of the distribution plate by changing the distribution plate structure and the air intake combination mode. However, these gas distributors do not consider the influence of wide screening distribution of particle size during the design process, and cannot solve the problems of particle separation and stratification and large-scale carryover. Therefore, a reasonably designed air intake device is of great significance to improving the fluidization quality in the fluidized bed, thereby improving the monomer yield and ensuring safe production. Summary of the invention

[0003] The present invention aims to provide an air intake assembly device for an organosilicon fluidized bed and an organosilicon fluidized bed. The air intake assembly and the fluidized bed have reasonable structures, are conducive to solving the problem of distribution plate blockage, reduce the wear of silicon powder particles on heat exchange tubes, improve silicon powder surface renewal and the mixing efficiency of methyl chloride gas and silicon powder particles, thereby improving monomer yield and realizing online pushing.

[0004] The technical solution of the present invention provides, on the one hand, a high-efficiency air intake assembly for an organosilicon fluidized bed, wherein the air intake assembly comprises an air intake assembly comprising a bottom central air intake hole at the bottom of a vertebral component and an injection device on a side wall.

[0005] The central air inlet is cylindrical, and its diameter is 0.08-0.15 times the diameter of the upper part of the cone component, for allowing the entry of methyl chloride gas. The methyl chloride gas enters the fluidized bed reactor vertically from the central hole at a relatively high speed, which can reduce the accumulation of silicon powder particles on the wall and the blockage of silicon powder particles at the central opening.

[0006] The injection device includes an annular tube section, an inlet section and an injection pipe; the annular tube section surrounds the outside of the cone body component and is used to provide a pressure environment to ensure that the raw material methyl chloride gas is ejected from the nozzle at a higher gas speed to form a swirl. The injection pipe penetrates into the interior of the cone body component; the inlet section is fixed on the side wall of the cone between the annular tube section and the injection pipe, and the diameter gradually decreases.

[0007] A plurality of injection pipes are installed in the inlet section, and the length of the injection pipes is between 50-300 mm and the diameter is between 5-20 mm.

[0008] The injection pipe is installed in the inlet section on the same cross section of the cone, deviating from the radial direction by 30-50° and tilted upward, so as to realize the upward flow of methyl chloride gas in a rotating state in the fluidized bed. The side wall injection air intake can increase the radial mixing of silicon powder particles and the renewal of the silicon powder particle surface, which is conducive to a more uniform distribution of silicon powder particles in the radial and axial directions.

[0009] The vertebral body component is provided with symmetrically arranged silicon powder feeding port and contact body return port; and the silicon powder feeding port and contact body return port are arranged between the central air inlet and the injection device, so as to realize the entry and return of silicon powder.

[0010] Another object of the present invention is to provide an organosilicon fluidized bed, comprising the air intake assembly device.

[0011] The upper part of the cone component is connected to the fluidized bed body through a flange and fixed with bolts; an expansion section is arranged on the upper part of the fluidized bed body, and the diameter of the expansion section is 1.2-1.5 times the diameter of the fluidized bed body.

[0012] An upper head is arranged at the upper part of the expansion section, and a material outlet is arranged at the upper part of the upper head. The fresh silicon powder is added to the fluidized bed reactor from the feeding port, and the silicon powder recovered from the cyclone separator re-enters the bed from the return port.

[0013] A method for preparing dimethyldichlorosilane monomer, using the organosilicon fluidized bed to react and preparing the monomer, the preparation steps are as follows: Fresh silicon powder enters the vertebral body from the silicon powder feeding port and mixes with the methyl chloride gas from the bottom center air inlet. At the same time, the methyl chloride gas enters the vertebral body from the injection device. Under the reaction thermometer pressure condition, in the vertebral body, the methyl chloride gas flows upward with the silicon powder, forming a jet fluidization and entering the fluidized bed, so that the methyl chloride gas forms an ascending and rotating state in the fluidized bed to react and prepare dimethyldichlorosilane monomer.

[0014] The flow rate ratio of the amount of methyl chloride gas entering from the bottom center air inlet hole to the amount entering from the injection device is 0.3-0.6; the speed of methyl chloride gas entering the cone component from the bottom center air inlet hole is 3-10 m / s; the speed of methyl chloride gas entering the cone component from the injection device is 150-300 m / s. This air intake combination ensures that the silicon powder particles are well dispersed in the axial and radial directions in the fluidized bed, which is conducive to reducing the accumulation of silicon powder particles in the wall area, reducing the wear of silicon powder particles on the heat exchange tube, and solving the problem of gas distribution plate blockage, and can realize online pushing.

[0015] In some embodiments, a fresh silicon powder feeding port and a silicon powder return port are installed on the side wall of the cone above the central hole. Fresh silicon powder is added to the fluidized bed reactor from the feeding port, and unreacted silicon powder particles are carried out of the fluidized bed from the top head by the methyl chloride gas and enter the cyclone separator, while the silicon powder recovered from the cyclone separator re-enters the bed from the return port.

[0016] Beneficial Effects The object of the present invention is to provide an efficient air intake assembly device for an organosilicon fluidized bed. The air intake assembly has a reasonable structure, is conducive to reducing the accumulation of silicon powder particles in the wall area, ensures that the silicon powder particles are evenly distributed in the axial and radial directions, reduces particle separation, and improves the mixing efficiency of methyl chloride gas and silicon powder particles, thereby improving the monomer yield.

[0017] The key points and protection points of the present invention.

[0018] High-efficiency air intake assembly and main structure of organic silicon fluidized bed. The organic silicon fluidized bed of the present invention can reduce the accumulation of silicon powder particles in the wall area, ensure uniform distribution of silicon powder particles in the axial and radial directions, increase the particle circulation speed, and improve the monomer yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the organosilicon fluidized bed of the present invention.

[0020] Figure 2 It is a top view of the structural schematic diagram of the injection device.

[0021] Figure 3 Simplified front view of the tapered component.

[0022] In the above device, the bottom center air inlet 1, the fresh silicon powder feeding port 2, the contact body return port 3, the side wall injection air inlet 4, the lower cone 5, the fluidized bed body 6, the expansion section 7, the upper head 8, the material outlet 9, the annular pipe section 10, the inlet section 11, and the injection pipe 12. DETAILED DESCRIPTION

[0023] In order to better understand the technical solution of the present invention, the content of the present invention is further described below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0024] Example 1 See also Figure 1 , a high-efficiency air intake assembly for an organosilicon fluidized bed, the air intake assembly comprising a combined air intake method of arranging a bottom central air intake hole 1 at the bottom of a vertebral component and an injection device 4 on the side wall.

[0025] The central air inlet hole 1 is cylindrical, and its diameter is 0.12 times the diameter of the upper part of the cone component, and is used to allow the entry of methyl chloride gas.

[0026] The injection device 4 includes an annular tube section 10, an inlet section 11 and an injection pipe 12; the annular tube section 10 surrounds the outside of the cone component to enable the entry of methyl chloride gas and provide a suitable pressure environment; the injection pipe 12 penetrates into the interior of the cone component; the injection pipe 12 is fixed on the side wall of the cone between the annular tube section 10 and the inlet section 11, and the diameter gradually decreases.

[0027] A plurality of injection pipes 12 are installed in the inlet section 11. The injection pipes 12 are 240 mm long and 16 mm in diameter. The injection pipes are made of pressure-resistant carbon steel.

[0028] The injection pipe 12 is installed in the inlet section 11 at a 45° deviation from the radial direction on the same cross section of the cone, so as to enable the methyl chloride gas to be fed in a rotating state and rise into the fluidized bed.

[0029] The vertebral body component is also symmetrically provided with a silicon powder feeding port 2 and a contact body return port 3; and the silicon powder feeding port 2 and the contact body return port 3 are arranged between the central air inlet 1 and the injection device 4, for realizing the entry and return of silicon powder.

[0030] Example 2 An organic silicon fluidized bed, wherein the air intake assembly adopts the structure of Example 1. The upper part of the cone component in the air intake assembly is connected to the fluidized bed body 6 through a flange and fixed with bolts; an expansion section 7 is provided on the upper part of the fluidized bed body 6, and the diameter of the expansion section 7 is 1.2 times the diameter of the fluidized bed body 6. An upper end cap is provided on the upper part of the expansion section, and a material outlet is provided on the upper part of the upper end cap.

[0031] Example 3 A method for preparing dimethyldichlorosilane monomer, using the organosilicon fluidized bed described in Example 2 for reaction, the preparation steps are as follows: Fresh silicon powder enters the cone part from the silicon powder feeding port 2 and mixes with the methyl chloride gas from the bottom center air inlet 1. At the same time, the methyl chloride gas enters the cone part from the injection device 4. Under the reaction temperature and pressure conditions (the reaction temperature is between 285-325℃ and the pressure is between 0.15-0.35MPa), in the cone part, the methyl chloride gas flows upward with the silicon powder, forming a spouting fluidization and entering the fluidized bed, so that the methyl chloride gas forms an upward and rotating state in the fluidized bed to react and prepare dimethyldichlorosilane monomer. Fresh silicon powder is added to the fluidized bed reactor from the feeding port, and the unreacted silicon powder particles are taken out of the fluidized bed from the top head by the methyl chloride gas and enter the cyclone separator, while the silicon powder recovered from the cyclone separator re-enters the bed from the return port.

[0032] The flow ratio of the amount of methyl chloride gas entering from the bottom center air inlet 1 to the amount entering from the injection device 4 is 0.5; the speed of the methyl chloride gas entering the cone body component from the bottom center air inlet 1 is 10 m / s; the speed of the methyl chloride gas entering the cone body component from the injection device 4 is 300 m / s. The technical solution of the present invention can ensure that there is no blockage problem within 3 months of operation, and the accumulation of silicon powder on the wall is small, which does not affect the stable production of materials; the air intake method combining spraying and side wall jet is adopted to increase the axial and radial mixing of silicon powder particles, increase the circulation amount of silicon powder particles, and thus improve the reaction efficiency, so that the single-pass conversion rate of methyl chloride can reach 55%, and the monomer space-time yield can reach 280kg / t silicon powder•h.

Claims

1. A high-efficiency air intake assembly for an organosilicon fluidized bed, characterized in that: The air intake assembly device comprises a combined air intake method in which a bottom central air intake hole (1) is arranged at the bottom of the vertebral body component and an injection device (4) is arranged on the side wall.

2. The high-efficiency air intake assembly for an organosilicon fluidized bed according to claim 1, characterized in that: The central air inlet (1) is cylindrical, and its diameter is 0.08-0.15 times the diameter of the upper part of the cone component, and is used to allow the entry of methyl chloride gas.

3. The high-efficiency air intake assembly for an organosilicon fluidized bed according to claim 1, characterized in that: The injection device (4) comprises an annular tube section (10), an inlet section (11) and an injection pipe (12); the annular tube section (10) surrounds the outside of the cone component and is used to allow the entry of methyl chloride gas and provide a suitable pressure environment; the injection pipe (12) penetrates into the interior of the cone component; the inlet section (11) is fixed on the side wall of the cone between the annular tube section (10) and the injection pipe (12), and the diameter gradually decreases.

4. The high-efficiency air intake assembly for an organosilicon fluidized bed according to claim 3, characterized in that: A plurality of injection pipes (12) are installed in the inlet section (11), and the injection pipes (12) have a length between 50 and 300 mm and a diameter between 5 and 20 mm.

5. The high-efficiency air intake assembly for an organosilicon fluidized bed according to claim 4, characterized in that: The injection pipe is installed at the end of the inlet section (11) on the same cross section of the cone, with a deviation of 30-50 degrees from the radial direction, so as to realize the upward flow of methyl chloride gas in a rotating state in the fluidized bed.

6. The high-efficiency air intake assembly for an organosilicon fluidized bed according to claim 1, characterized in that: The vertebral body component is also symmetrically provided with a silicon powder feeding port (2) and a contact body return port (3); and the silicon powder feeding port (2) and the contact body return port (3) are arranged between the central air inlet (1) and the injection device (4) to enable the entry of silicon powder and the entry of contact body return material.

7. An organosilicon fluidized bed, characterized in that: It comprises the air intake assembly device as described in any one of claims 1 to 6.

8. The organosilicon fluidized bed according to claim 7, characterized in that: The upper part of the cone component is connected to the fluidized bed body (6) via a flange and fixed with bolts; an enlarged section (7) is provided on the upper part of the fluidized bed body (6), and the diameter of the enlarged section (7) is 1.2-1.5 times the diameter of the fluidized bed body (6).

9. A method for preparing dimethyldichlorosilane monomer, characterized in that: The method is prepared by reacting the organosilicon fluidized bed according to claim 7 or 8, and the preparation steps are as follows: Fresh silicon powder enters the vertebral body from the silicon powder feeding port and mixes with the methyl chloride gas from the bottom center air inlet hole. At the same time, the methyl chloride gas enters the vertebral body from the injection device. Under the reaction temperature and pressure conditions, the methyl chloride gas flows upward in the vertebral body with the silicon powder. The injection air intake method allows the methyl chloride gas to form a radially mixed and enhanced swirl state in the fluidized bed, which is beneficial to the reaction and prepares dimethyldichlorosilane monomer.

10. The method for preparing dimethyldichlorosilane monomer according to claim 9, characterized in that: The flow rate ratio of the methyl chloride gas entering from the bottom center air inlet hole to the flow rate of the methyl chloride gas entering from the injection device is 0.3-0.6; The speed of methyl chloride gas entering the vertebral body from the bottom center air inlet is 3-10 m / s; The speed of methyl chloride gas entering the vertebral body from the injection device is 150-300 m / s.

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