Device for synthesizing trichlorosilane from organic silicon waste contact body

Abstract

The utility model discloses a device for synthesizing trichlorosilane from an organic silicon waste contact body, which is characterized in that a hydrogen chloride steel cylinder, a hydrogen steel cylinder and a nitrogen storage tank are respectively connected with a main pipeline through pipelines, and the main pipeline is connected with a preheater; the preheater is connected with the reaction tube, an outlet of the reaction tube is connected with the condenser, and the condenser is connected with the liquid collecting bottle. The hydrogen chloride steel cylinder is connected with the main pipeline through a hydrogen chloride gas pressure reducing valve, a hydrogen chloride gas flow meter and a needle valve I in sequence. The hydrogen steel cylinder is connected with the header pipe through a hydrogen gas pressure reducing valve, a hydrogen gas flow meter and a needle valve II respectively; the nitrogen storage tank is connected with the main pipe through a nitrogen pressure reducing valve, a nitrogen flow meter and a needle valve III respectively; and a pressure gauge is arranged between the main pipeline and the preheater. The utility model provides a small-scale test device and method for synthesizing trichlorosilane from organic silicon waste contact bodies, the operation is simple, and test data has important guiding significance for engineering device construction.

Description

Technical Field

[0001] This utility model belongs to the field of comprehensive utilization technology of waste, specifically involving a device for synthesizing trichlorosilane from organosilicon waste catalyst. Background Technology

[0002] Organosilicon waste catalysts are residual reactants from the production of methylchlorosilane. Containing elements such as Si, C, Cu, and Fe, they are black solid powders with high reactivity and are extremely prone to spontaneous combustion. Due to their hazardous and environmental impacts, their proper treatment and resource utilization are crucial. Some research and practices are dedicated to exploring resource-based recycling technologies for organosilicon waste catalysts, treating them using specific methods to recover copper.

[0003] CN110791650A, "A Method for Recovering Metallic Copper from Waste Organosilicon Catalysts," describes a method for recovering metallic copper from waste organosilicon catalysts. The method includes oxidative roasting of the waste organosilicon catalysts to remove organic impurities, followed by carbon-deficient reduction and heavy liquid separation to obtain metallic copper. This method has advantages such as low pollution, high copper yield, and high material utilization.

[0004] CN202210488587.X, "A Method for Recovering Copper from Waste Organosilicon Catalysts," describes a method for recovering copper from waste organosilicon catalysts. The method involves stirring the waste organosilicon catalysts, water, and additives to obtain water-leached residue and water-leached leachate. The water-leached residue is then acid-leached, and an oxidant is added to react, yielding copper-removed residue and copper-containing leachate. The copper-containing leachate is then purified by degreasing and its acidity is adjusted to obtain copper electrodeposition solution. This solution is then subjected to two-stage vortex electrodeposition to produce Grade A copper (Cu>99.99%) and Standard No. 2 copper (Cu>99.90%) conforming to GB / T 467-2010 standards, respectively.

[0005] CN116212871A, entitled "A Method for Preparing Ternary Copper Catalysts by Gas-Phase Reduction of Waste Organosilicon Catalysts," discloses a method for preparing ternary copper catalysts by gas-phase reduction of waste organosilicon catalysts. The method includes loading oxidized and roasted waste organosilicon catalysts and a reducing medium into a tubular reactor; introducing a mixed reaction gas of fluorine and dilution gas into the tubular reactor; controlling the reaction temperature through the tubular reactor; and recovering the product from the tubular reactor after the reaction, directly obtaining the ternary copper catalyst through heavy liquid separation.

[0006] Other studies have utilized waste catalysts to synthesize organosilicon monomers. For example, waste catalysts discharged from fluidized beds and recovered from external cyclone separators can be treated with N2 at 1100°C for 3 minutes, then placed in a stirred bed and reacted with MeCl at 300°C to produce methylchlorosilane monomers. High-temperature N2 treatment is highly effective in improving catalyst activity (yield) and Me2SiCl2 selectivity. Another example is the production of phenylchlorosilane monomers by heating waste catalysts with halobenzenes in the presence of a copper catalyst.

[0007] Patent CN101391775 disclosed a method for synthesizing trichlorosilane from waste catalysts in organochlorosilane production. Using waste catalysts as raw materials, trichlorosilane is synthesized via a direct gas-solid phase method with dried HCl diluted with a diluent gas. The prepared trichlorosilane can be used to synthesize monocrystalline silicon, polycrystalline silicon, high-purity silicon, and special organosilanes.

[0008] Currently, there are no engineering cases of synthesizing trichlorosilane from waste organosilicon catalysts, either domestically or internationally, and there are few reports on its reaction research. This is because there are certain difficulties in producing trichlorosilane from waste organosilicon catalysts. Waste catalysts usually contain a large amount of copper and a small amount of zinc and other impurities, making it difficult to prepare high-purity trichlorosilane. In addition, the content of each component in the waste catalyst fluctuates greatly depending on the organosilicon synthesis process, and the high activity and strong exothermic reaction process make it difficult to control the reaction rate. Summary of the Invention

[0009] This invention aims to disclose an apparatus for synthesizing trichlorosilane from waste organosilicon catalysts, to study the reaction conditions and characteristics of synthesizing trichlorosilane from waste catalysts, to provide reliable basic data for the engineering of direct synthesis of trichlorosilane from waste catalysts, and to develop higher utilization value for waste catalysts, so as to achieve effective resource utilization and environmental protection.

[0010] An apparatus for synthesizing trichlorosilane from waste catalysts, wherein hydrogen chloride cylinders, hydrogen cylinders, and nitrogen storage tanks are respectively connected to a main pipeline via pipelines, and the main pipeline is connected to a preheater;

[0011] The preheater is connected to the reaction tube, the outlet of the reaction tube is connected to the condenser, and the condenser is connected to the collection bottle.

[0012] The hydrogen chloride cylinder is connected to the main pipeline in sequence via a hydrogen chloride gas pressure reducing valve, a hydrogen chloride gas flow meter, and a needle valve.

[0013] Hydrogen cylinders are connected to the main pipe via hydrogen gas pressure reducing valve, hydrogen gas flow meter, and needle valve II; nitrogen storage tanks are connected to the main pipe via nitrogen pressure reducing valve, nitrogen flow meter, and needle valve III.

[0014] A pressure gauge is installed between the main pipeline and the preheater.

[0015] Stainless steel is preferred for hydrogen chloride pipelines, nitrogen pipelines, and valves and flow meters on these pipelines. Pressure-resistant glass is used for the hydrogen chloride preheater, reactor, condenser, liquid collector, tail gas absorber, and connecting pipelines between them.

[0016] There is a preheating resistance furnace outside the preheater, and a reaction resistance furnace outside the reaction tube.

[0017] The lower part of the reaction tube is equipped with a fixed sieve plate, and the upper part is filled with quartz wool after the waste catalyst is loaded.

[0018] A method for synthesizing trichlorosilane from waste catalysts includes the following steps:

[0019] Weigh an appropriate amount of waste catalyst and place it in the reaction tube. A fixed sieve plate is set at the bottom of the reaction tube and quartz wool is set at the top.

[0020] A preheater is connected to the lower part of the reaction tube. Nitrogen gas is used to purge the preheater and replace the air in the reaction tube.

[0021] Set the temperature control programs for the preheating resistance furnace and the reaction resistance furnace, and start them;

[0022] Introduce HCl gas or a mixture of HCl and H2;

[0023] Turn on the condenser to circulate condensate water, maintaining a condensate temperature of -10 to 10℃. The reaction products are condensed into a collection bottle, while non-condensable acidic gases are absorbed by the alkaline solution. After the reaction is complete, close the reaction gas valve, open the nitrogen valve for purging, stop heating, and analyze the material in the collection bottle. After the system cools to room temperature, disassemble the reaction tube and analyze the internal residue.

[0024] The waste catalyst has a particle size of less than 20 μm and a composition of Si: 60%-85%; Cu: 5%-15%; Fe: 2%-5%; Aluminum: 0.5%-3%; Carbon: 1-5%; the fixed sieve plate has a pore size of less than 10 μm; and the quartz wool has a size of 1-3 μm.

[0025] The upper and lower ends of the reaction tube are wrapped with high-temperature resistant glass fiber tape, and the outlet of the reaction tube and the connection with the glass instrument are wrapped with PTFE tape before connection.

[0026] The inlet flow rate of hydrogen chloride gas is 10-25 mL / min; the inlet flow rate of hydrogen gas is 3-8 mL / min. The amount of nitrogen gas used in the nitrogen replacement system is not less than 6 times the volume of the reaction tube.

[0027] Further preferred is that the hydrogen chloride gas inlet flow rate is 15-25 mL / min; and the hydrogen gas inlet flow rate is 5-8 mL / min.

[0028] The reaction pressure inside the reactor is 0.1-0.5 MPa, and the reaction time is 20-30 h.

[0029] The method for synthesizing trichlorosilane from waste catalysts is carried out using the aforementioned apparatus.

[0030] This utility model has the following features:

[0031] 1. The system is simple and can be set up in the laboratory with low investment.

[0032] 2. The reactive gas enters from the bottom of the reaction tube. The reactive gas entering from the top of the reaction tube continuously compacts the waste catalyst, causing pressure changes inside the reaction tube and resulting in fluctuations in the reaction process.

[0033] 3. Once the program is preset, the reaction process requires no manual intervention.

[0034] 4. The experimental data obtained have good regularity and strong guiding significance for equipment-based production: it can explore the effect of reaction temperature on reaction selectivity, analyze the particle size changes of waste catalyst under different reaction degrees, and explore the highest conversion rate of waste catalyst.

[0035] 5. The PTFE tape at the instrument connection can prevent trichlorosilane from hydrolyzing and cross-linking after a leak occurs at the connection, which would make the device impossible to disassemble. It can also improve the airtightness of the device.

[0036] 6. Since the reactant gas enters from the bottom, it may cause local channels in the waste catalyst layer and uneven distribution of reactant gas, which will reduce the conversion rate and selectivity of the waste catalyst. Therefore, a sieve plate with small and dense pores is selected to distribute the reactant gas.

[0037] 7. The addition of an extra gas source could be used to explore how to improve the selectivity of trichlorosilane. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the device of this utility model, wherein:

[0039] 1. Hydrogen chloride cylinder; 2. Hydrogen cylinder; 3. Hydrogen chloride gas pressure reducing valve; 4. Hydrogen chloride gas flow meter; 5. Needle valve one; 6. Hydrogen gas pressure reducing valve; 7. Hydrogen gas flow meter; 8. Needle valve two; 9. Nitrogen; 10. Nitrogen gas pressure reducing valve; 11. Nitrogen gas flow meter; 12. Needle valve three; 13. Pressure gauge; 14. Preheating resistance furnace; 15. Reaction resistance furnace; 16. Preheater; 17. Reaction tube sieve plate; 18. Quartz wool; 19. Condenser; 20. Collection bottle; 21. Tail gas absorption; 22. Reaction tube. Detailed Implementation

[0040] The technical solution of this utility model will be further described and illustrated below through embodiments.

[0041] Example 1

[0042] This utility model patent discloses an apparatus for synthesizing trichlorosilane from waste catalysts. A hydrogen chloride cylinder 1 is connected to a main pipe via a hydrogen chloride gas pressure reducing valve 3, a hydrogen chloride gas flow meter 4, and a needle valve 5. A hydrogen cylinder 2 is connected to the main pipe via a hydrogen gas pressure reducing valve 6, a hydrogen gas flow meter 7, and a needle valve 8. A nitrogen source 9 is connected to the main pipe via a nitrogen gas pressure reducing valve 10, a nitrogen gas flow meter 11, and a needle valve 12. A pressure gauge 13 is installed between the main pipe and the preheater 16. The preheater 16 is connected to the reaction tube 22, followed by a glass bend, a condenser 19, a collection bottle 20, and a tail gas absorber 21. A preheating resistance furnace 14 is located outside the preheater, and a reaction resistance furnace 15 is located outside the reaction tube. A fixed sieve plate 17 is installed in the lower part of the reaction tube 22, and quartz wool 18 is plugged into the upper part after the waste catalysts are filled.

[0043] The above-mentioned apparatus is used to perform the following process:

[0044] Weigh 10g of waste organosilicon catalyst, with a particle size of 5-19μm and a quartz wool size of 1-3μm, and follow the instructions. Figure 1 The apparatus was set up with a reaction tube approximately 55 cm long and 1.5–1.7 cm in inner diameter. The sieve plate had a aperture of 5–10 μm. Nitrogen purging flow rate was set at 25 mL / min for 30 min. The preheating resistance furnace was programmed with the following steps: initial temperature 25℃, temperature increase to 200℃ in 60 min, stabilization for 1440 min, and then heating stopped. The reaction resistance furnace was programmed with the following steps: initial temperature, temperature increase to 250℃ in 60 min, stabilization for 1440 min, and then heating stopped. The condensate temperature was set to -10℃, and circulation was initiated. After system purging, 10 mL / min of HCl gas and 0 mL / min of H2 gas were introduced, with a total pressure of 0.2 MPa and a flow rate of 10 mL / min. The resistance furnace was then started. The experiment ended after 25 hours. Samples were taken for analysis, HCl gas was stopped, and the system was purged with nitrogen at 25 mL / min. The waste catalyst conversion rate was 36.94%, and the product HSiCl3 content was 80.56%.

Claims

1. An apparatus for synthesizing trichlorosilane from organosilicon waste catalyst, characterized in that, Hydrogen chloride cylinder (1), hydrogen cylinder (2), and nitrogen storage tank (9) are connected to the main pipeline via pipelines, and the main pipeline is connected to the preheater (16); The preheater (16) is connected to the reaction tube (22), the outlet of the reaction tube (22) is connected to the condenser (19), and the condenser (19) is connected to the collection bottle (20).

2. The apparatus for synthesizing trichlorosilane from organosilicon waste catalyst according to claim 1, characterized in that, The hydrogen chloride cylinder (1) is connected to the main pipeline in sequence via the hydrogen chloride gas pressure reducing valve (3), the hydrogen chloride gas flow meter (4), and the needle valve (5).

3. The apparatus for synthesizing trichlorosilane from organosilicon waste according to claim 2, characterized in that, The hydrogen cylinder (2) is connected to the main pipe via the hydrogen gas pressure reducing valve (6), the hydrogen gas flow meter (7), and the needle valve (8); the nitrogen storage tank (9) is connected to the main pipe via the nitrogen pressure reducing valve (10), the nitrogen flow meter (11), and the needle valve (12). A pressure gauge (13) is installed between the main pipeline and the preheater (16).

4. The apparatus for synthesizing trichlorosilane from organosilicon waste catalyst according to claim 1, characterized in that, There is a preheating resistance furnace (14) outside the preheater (16) and a reaction resistance furnace (15) outside the reaction tube.

5. The apparatus for synthesizing trichlorosilane from organosilicon waste catalyst according to claim 1, characterized in that, The lower part of the reaction tube (22) is equipped with a fixed sieve plate (17), and the upper part is filled with quartz wool (18) after the waste catalyst is filled.

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