Device and method for purifying tetramethylsilane

Abstract

The invention discloses a tetramethylsilane purification device and method, and the device comprises a raw material pretreatment assembly which comprises a station for placing a crude TMS storage tank and a precision filter connected to a raw material pipe, and the station is provided with a heating device; the vaporization assembly is a vaporizer communicated with the raw material pipe of the raw material pretreatment assembly; the membrane separation assembly comprises a membrane assembly of a ZSM-5 molecular sieve membrane with height b-axis orientation, the b-axis orientation value of the ZSM-5 molecular sieve membrane in the membrane assembly is 0.90-95, the thickness of a separation layer is 1-3 microns, and a membrane carrier is an alpha-Al2O3 porous ceramic tube; an inlet of the membrane component is communicated with a vaporization outlet of the vaporization component; the condensation and collection assembly comprises a condenser communicated with a second connecting pipe on the permeation side of the membrane separation assembly and a product tank communicated with an outlet of the condenser; the tail gas storage device is communicated with the first connecting pipe on the interception side of the membrane separation assembly. The continuous purification of the TMS is realized, the energy consumption is reduced, and the purity is improved to an electronic grade.

Description

Technical Field

[0001] This invention belongs to the field of electronic chemicals technology, specifically relating to a tetramethylsilane purification apparatus and method, particularly a tetramethylsilane purification apparatus based on a highly b-axis oriented ZSM-5 molecular sieve membrane and a TMS purification method based on the apparatus. Background Technology

[0002] Tetramethylsilane (TMS) is a critical precursor material in semiconductor manufacturing, and its purity directly affects the stability of chip fabrication processes. The main impurity in industrial crude TMS is isopentane (iC5), and the two differ in boiling point by only 1 K (TMS boiling point 299.7 K, iC5 boiling point 300.7 K). Conventional separation techniques have significant limitations.

[0003] 1. Traditional distillation method: requires a high theoretical plate number (≥100 plates), repeated heating and condensation lead to extremely high energy consumption, and it is difficult to stably achieve 99.99% electronic grade purity, resulting in low efficiency in continuous production (disclosed in the background technology of the disclosure document).

[0004] 2. Conventional ZSM-5 membrane separation method: This method uses molecular sieve membranes with randomly oriented crystals, resulting in tortuous pores, high mass transfer resistance, and a membrane flux ≤ 1.5 kg·m³. -2 ·h -1 It cannot effectively retain iC5 and has not achieved separation of the TMS / iC5 system;

[0005] 3. Adsorption method: such as the "adsorption column + filter" process disclosed in CN119113539A, which relies on 13X or ZSM-5 powder adsorbent, requires periodic regeneration, and is an intermittent operation, which is difficult to meet the needs of large-scale mass production; the "liquid-solid adsorption → gas adsorption" process, although the purity reaches 99.99%, has a single batch processing time of ≥4h, which is inefficient.

[0006] 4. Other applications of ZSM-5: Sinopec has disclosed that ZSM-5 is used as a solid acid catalyst in oil refining and chemical industry, and Sun Yuhan / Gao Peng's team has disclosed that HZSM-5 is used for CO2 hydrogenation to produce aromatics (by adjusting the b-axis length to improve catalytic selectivity). Both of these are in the field of catalysis and are unrelated to TMS membrane separation.

[0007] In summary, existing technologies cannot solve the purification challenges of "low energy consumption, continuous operation, and high purity" for TMS and iC5 systems with very similar boiling points, and new separation technologies need to be developed.

[0008] Therefore, in view of the above-mentioned technical problems, it is necessary to provide a tetramethylsilane purification apparatus and method. Summary of the Invention

[0009] The purpose of this invention is to provide a tetramethylsilane purification apparatus and method.

[0010] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution:

[0011] A tetramethylsilane purification apparatus based on a highly b-axis oriented ZSM-5 molecular sieve membrane includes:

[0012] Raw material pretreatment components: including a station for housing a storage tank containing crude TMS and a precision filter connected to the raw material pipe; the station is equipped with a heating device.

[0013] Vaporization component: A vaporizer connected to the raw material pipe of the raw material pretreatment component;

[0014] Membrane separation module: a membrane module comprising a highly b-axis oriented ZSM-5 molecular sieve membrane, wherein the b-axis orientation value of the ZSM-5 molecular sieve membrane in the membrane module is 0.90-95, the separation layer thickness is 1-3 μm, and the membrane support is an α-Al2O3 porous ceramic tube; the inlet of the membrane module is connected to the vaporization outlet of the vaporization module;

[0015] Condensation collection assembly: including a first condenser (condensation temperature 5-15℃) connected to a second connecting pipe on the permeate side of the membrane separation assembly, and a product tank connected to the condenser outlet;

[0016] Exhaust gas treatment assembly: an exhaust gas device (such as an exhaust gas storage tank, incinerator, etc.) connected to the first connecting pipe on the interception side of the membrane separation assembly.

[0017] In one or more embodiments of the present invention, a tetramethylsilane purification apparatus based on a highly b-axis oriented ZSM-5 molecular sieve membrane includes:

[0018] Raw material pretreatment assembly: includes a station for housing a storage tank containing coarse TMS and a precision filter (filtration accuracy 0.1-1μm, used to remove particulate impurities from the raw material) connected to the raw material pipe; a heating device is installed at the station.

[0019] Vaporization component: a vaporizer connected to the raw material pipe of the raw material pretreatment component; preferably, the vaporization temperature is controllable within the range of 40-80℃, and is equipped with a temperature sensor and a PID controller;

[0020] Membrane separation module: A membrane module comprising a highly b-axis oriented ZSM-5 molecular sieve membrane, wherein the b-axis orientation value of the ZSM-5 molecular sieve membrane in the membrane module is ≥0.85, the separation layer thickness is 1-3μm, and the membrane support is an α-Al2O3 porous ceramic tube (pore size 0.1-1μm); the inlet of the membrane module is connected to the vaporization outlet of the vaporization module, and the inlet and outlet of the membrane module are respectively equipped with a pressure sensor (range 0-1MPa) and a flow controller (control range 3-10mL / min).

[0021] Condensation collection assembly: including a shell-and-tube condenser (condensation temperature 5-15℃) connected to the second connecting pipe on the permeate side of the membrane separation assembly, and an electronic-grade TMS product tank connected to the condenser outlet;

[0022] Exhaust gas treatment unit: an exhaust gas storage device connected to the first connecting pipe on the retention side of the membrane separation unit, used to treat unpermeated isopentane (iC5) and trace amounts of TMS.

[0023] In one or more embodiments of the present invention, the ZSM-5 molecular sieve membrane is prepared by a hydrothermal synthesis method, the preparation steps of which include:

[0024] (1) Carrier pretreatment: α-Al2O3 ceramic tubes were soaked in 1mol / L hydrochloric acid for 2h, rinsed with deionized water until neutral, dried at 120℃, and then calcined at 550℃ for 2h.

[0025] (2) Seed coating: Disperse ZSM-5 seed crystals (particle size 50-100nm) in ethanol, sonicate for 30min to obtain seed solution with mass concentration of 1%-3%, and coat the seed solution on the outer surface of the carrier by immersion method and dry at 60℃;

[0026] (3) Hydrothermal synthesis: The carrier coated with seed crystals is placed vertically in the reactor, the synthesis solution is added, and static crystallization is carried out at 160-180℃ for 24-48h. The molar composition of the synthesis solution includes: SiO2:Al2O3:template agent:H2O=100:1:10-15:2000-3000.

[0027] (4) Post-treatment: The crystallized carrier is taken out, rinsed with deionized water until pH=7, dried at 120℃, and then calcined at 550℃ for 6h to remove the template agent, and a highly b-axis oriented ZSM-5 molecular sieve membrane is obtained.

[0028] In one or more embodiments of the present invention, the membrane separation unit is operated with the following parameter settings: membrane operating temperature 30-60℃, transmembrane pressure difference 0.3-0.7MPa, at which time the TMS single-pass yield is ≥75% and the membrane flux is ≥2.5kg·m³. -2 ·h -1 Preferably, the transmembrane pressure difference is 0.4-0.6 MPa, and the membrane operating temperature is 40-50℃. Preferably, the membrane operating temperature is 40-50℃. Preferably, the difference between the vaporization temperature and the membrane operating temperature is ≤20℃.

[0029] In one or more embodiments of the present invention, the gaseous feedstock enters the feedstock side of the membrane separation unit after the flow rate is precisely controlled by a flow controller to be 3-10 mL / min.

[0030] In one or more embodiments of the present invention, the membrane module is maintained at an operating temperature of 30-60°C. Temperature affects the molecular diffusion rate; too low a temperature results in low flux, while too high a temperature may affect the long-term stability of the membrane. A preferred temperature is 40-50°C. The feed-side pressure is maintained at the aforementioned 0.3-1.0 MPa, while the permeate-side pressure is maintained at a lower pressure, typically 0-0.1 MPa (absolute pressure), via a back pressure valve. The resulting transmembrane pressure difference (ΔP) is the core driving force for component permeation, preferably ΔP is 0.3-0.7 MPa. Under precisely controlled temperature and pressure conditions, TMS molecules with smaller kinetic diameters can more effectively permeate selectively to the other side of the membrane through the straight channels (~0.55 nm) of the highly b-axis oriented ZSM-5 membrane, while slightly larger iC5 molecules are significantly retained.

[0031] In one or more embodiments of the present invention, the membrane module adopts a parallel structure of multiple ceramic tubes (2-10 tubes), with each ceramic tube having a length of 300-500 mm, an inner diameter of 8-12 mm, an outer diameter of 12-16 mm, and a total membrane area of ​​0.1-0.5 m². 2 To adapt to the needs of large-scale production.

[0032] In one or more embodiments of the present invention, the b-axis orientation value of the ZSM-5 molecular sieve membrane is determined by X-ray diffraction: the ratio of the diffraction peak intensity I(020) of the (020) crystal plane to the diffraction peak intensity I(111) of the (111) crystal plane is calculated, i.e., orientation value = I(020) / I(111) ≥ 0.85. Preferably ≥ 0.90.

[0033] In one or more embodiments of the present invention, the vaporizer is a tubular vaporizer, heated by heat transfer oil, with a temperature control accuracy of ±1℃, to avoid local overheating that could lead to TMS decomposition.

[0034] In one or more embodiments of the present invention, the template agent is selected from: tetrapropylammonium hydroxide, tetrapropylammonium bromide or triethylamine.

[0035] In one or more embodiments of the present invention, the device-based TMS purification method includes the following steps:

[0036] (1) Raw material pretreatment: The raw material TMS is passed through a precision filter to obtain pretreated crude TMS;

[0037] (2) Vaporization: The pretreated crude TMS is fed into a vaporizer for vaporization to obtain a mixed gas phase of the raw materials;

[0038] (3) Membrane separation: The mixed gas phase is introduced into a membrane module including a pretreated ZSM-5 molecular sieve membrane with a high b-axis orientation. The membrane operating temperature is controlled at 30-60℃ and the transmembrane pressure difference is 0.3-0.7MPa. TMS molecules enter the permeate side through the membrane pores.

[0039] (4) Condensation and collection: The TMS gas phase on the permeation side is sent to the first condenser to be condensed into liquid and collected into the product tank to obtain electronic grade TMS with a purity ≥99.97%.

[0040] In one or more embodiments of the present invention, the device-based TMS purification method includes the following steps:

[0041] (1) Raw material pretreatment: The raw material TMS with an initial purity of 95%-98% (containing 52%-5% iC) is passed through a precision filter to obtain pretreated coarse TMS, and particles with a particle size ≥0.1μm are removed;

[0042] (2) Vaporization: The pretreated crude TMS is fed into a vaporizer and completely vaporized at 40-80℃ to obtain a mixed gas phase of the raw materials;

[0043] (3) Membrane separation: The mixed gas phase is passed into a membrane module including a pretreated ZSM-5 molecular sieve membrane with a high b-axis orientation. The membrane operating temperature is controlled at 30-60℃, the transmembrane pressure difference is 0.3-0.7MPa, and the feed flow rate is 3-10mL / min. TMS molecules enter the permeate side through the membrane pores, and iC5 is retained.

[0044] (4) Condensation and collection: The TMS gas phase on the permeation side is sent to the first condenser and condensed into liquid at 5-15℃. It is collected into the product tank to obtain electronic grade TMS with a purity ≥99.97%.

[0045] In one or more embodiments of the present invention, the pretreatment in step (3) is: to heat up to 300-350°C at a heating rate of 1-2°C / min and keep warm for 2-4 hours.

[0046] In one or more embodiments of the present invention, the crude TMS in step (2) is preheated before being fed into the tubular vaporizer. The preheating is carried out by uniformly raising the temperature to 30-40°C at a rate of 1-5°C / min.

[0047] Compared with existing technologies, the tetramethylsilane purification apparatus and method of the present invention overcome the major technical bottleneck of high energy consumption and low efficiency when using traditional distillation techniques to separate tetramethylsilane (TMS) and isopentane (iC5), which have extremely similar boiling points. Instead of relying on boiling point differences, it creatively utilizes the precise sieving capability unique to the highly b-axis oriented ZSM-5 molecular sieve membrane, achieving highly efficient separation based on the slight difference in molecular dynamic diameters between TMS and iC5, thus achieving a breakthrough in separation principles.

[0048] Furthermore, compared with existing technologies, the process flow of this invention is simple and compact, and continuous production can be achieved through vaporization, membrane separation, and condensation, with energy consumption far lower than that of complex distillation. At the same time, this technology has extremely high separation precision and can stably obtain electronic-grade tetramethylsilane products with a purity of over 99.99%, thus solving the purity bottleneck of high-end semiconductor materials.

[0049] (1) Reduced energy consumption: Compared with traditional distillation, energy consumption is reduced by more than 50% (only vaporization and membrane separation low-temperature operation are required).

[0050] (2) Improved purity: Under optimized conditions, the purity of TMS reaches 99.996%, far exceeding the requirements for electronic grade;

[0051] (3) Efficiency improvement: continuous operation, single-pass yield up to 80.5%, and membrane flux more than twice that of conventional membranes;

[0052] (4) Wide applicability: Specifically designed for TMS / iC5 systems with very similar boiling points, filling the gap in membrane separation technology for this system. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a schematic diagram of the process of a tetramethylsilane purification apparatus in one embodiment of the present invention;

[0055] Figure 2 This is a schematic diagram of the structure of a membrane separation component in one embodiment of the present invention;

[0056] Figure 3 The X-ray diffraction patterns are of the ZSM-5 membranes in the membrane separation components of Embodiments 1-3 of the present invention.

[0057] Explanation of key figure labels:

[0058] 1. Raw material gas cylinder, 2. Heating tape, 3. Vaporizer, 4. Flow controller, 5. First back pressure valve, 6. Second back pressure valve, 7. First condenser, 8. Second condenser, 9. Product cylinder, 10. Residue cylinder, 11. Metering pump, 21. Component end, 22. Membrane tube positioning plate, 23. Membrane tube, 24. Component cylinder, 25. First connecting pipe, 26. Second connecting pipe, 27. Gasket. Detailed Implementation

[0059] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments disclosed herein. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0060] The core innovation of this invention, a tetramethylsilane purification device based on a highly b-axis oriented ZSM-5 molecular sieve membrane, lies in its use of a highly b-axis oriented ZSM-5 molecular sieve membrane as a removal carrier for isopentane (iC5), the main impurity in industrial crude TMS. This membrane is prepared using a seeding method and a secondary growth method, ensuring that the b-axis (straight pore direction) is perpendicular to the carrier surface, forming a short and straight diffusion path. By controlling the membrane's b-axis orientation (≥0.85), the b-axis (straight pore direction) is made perpendicular to the carrier surface, forming a "short and straight" diffusion path, reducing mass transfer resistance. Combined with an integrated "pretreatment-vaporization-membrane separation-condensation" device, precise sieving is achieved.

[0061] like Figure 1 and 2As shown, a tetramethylsilane purification device based on a highly b-axis oriented ZSM-5 molecular sieve membrane may include: a raw material pretreatment component: including a station for housing a crude TMS storage tank / raw material gas cylinder 1 and a precision filter (filtration accuracy 0.1-1μm) connected to the raw material pipe, and a heating device such as a heating tape 2 is provided at the station; a vaporization component: a vaporizer 3 connected to the raw material pipe of the raw material pretreatment component, and a metering pump 11 may be installed on the raw material pipe; preferably, the vaporization temperature is controllable within a range of 40-80℃, and is equipped with a temperature sensor and a PID controller for temperature control; a membrane separation component: including a membrane module of a highly b-axis oriented ZSM-5 molecular sieve membrane, wherein the b-axis orientation value of the ZSM-5 molecular sieve membrane in the membrane module is ≥0.85, the separation layer thickness is 1-3μm, and the membrane carrier is an α-Al2O3 porous ceramic tube (pore size 0.1-1μm); and a membrane module. The inlet of the membrane module is connected to the vaporization outlet of the vaporization component, and a flow controller 4 can be further installed on the connecting pipe between the two; the condensation collection component includes a first condenser 7 / shell-and-tube condenser (condensation temperature 5-15℃) connected to the second connecting pipe 26 on the permeate side of the membrane separation component, and an electronic-grade TMS product cylinder 9 connected to the condenser outlet, and a first back pressure valve 5 can be installed on the second connecting pipe 26; the tail gas treatment component is a tail gas storage device connected to the first connecting pipe on the retrieval side of the membrane separation component, used to treat unpermeated isopentane (iC5) and trace amounts of TMS, and may further include a second condenser 8 / shell-and-tube condenser (condensation temperature 5-15℃) connected to the first connecting pipe on the retrieval side of the membrane separation component, and the condensed tail material is transported to the residual material cylinder 10 through the first connecting pipe 25, and a second back pressure valve 6 can be installed on the first connecting pipe 25. In addition, the inlet and outlet of the membrane module can be respectively equipped with a pressure sensor (range 0-1MPa) and a flow controller (control range 3-10mL / min).

[0062] Furthermore, the membrane separation assembly includes an assembly cylinder 24 with a cavity and assembly ends 21 formed at both ends of the assembly cylinder 24. The end of the assembly end 21 within the cavity is also provided with a membrane tube positioning plate 22 to form a restrictive space for supporting the membrane tube 23. A protective gasket 27 is also provided on the outside of the membrane tube positioning plate 22. The raw material enters the membrane tube 23 in the cavity from the feed side of the assembly cylinder 24 for separation. After separation, the high-purity raw material and the tail material are discharged through the second connecting pipe 26 and the first connecting pipe 25, respectively.

[0063] A specific process flow for the TMS purification method using this equipment can be as follows:

[0064] Step 1: Select a ZSM-5 molecular sieve membrane with a b-axis crystal preferred orientation value of not less than 0.85 and a separation layer thickness of 1-3 μm for activation. Programme the temperature to 300-350℃ at a heating rate of 1-2℃ / min and hold for 2-4 hours to thoroughly remove any residual template agent and adsorbents within the membrane pores. Load the activated molecular sieve membrane into a membrane module for gas separation testing.

[0065] Step 2: The pre-purified silane low-boiling point feedstock (TMS content 80%-90%, iC5 content 5-10%) is drawn from the feedstock tank and delivered to the vaporizer via a precision metering pump. During this stage, the feedstock needs to be preheated to a uniform temperature of 30-40°C before entering the vaporizer to avoid rapid vaporization that could lead to component segregation.

[0066] Step 3: The liquid feedstock is completely converted into a gaseous state in the vaporizer. The key control parameter for this process is the vaporization temperature, which should be strictly controlled within the range of 40-80℃. Too low a temperature will result in incomplete vaporization, and droplets may damage the membrane surface; too high a temperature may cause pyrolysis of the feedstock. The optimal vaporization temperature range is 60-70℃. The vaporizer outlet pressure is pre-controlled at 0.3-0.8 MPa to provide a pressure basis for subsequent membrane separation.

[0067] Step 4: The gaseous feedstock, after being precisely controlled at a flow rate of 3-10 mL / min by a flow controller, enters the feed side of the membrane separation module. The membrane module is maintained at an operating temperature of 30-60°C. Temperature affects the molecular diffusion rate; too low a temperature results in low flux, while too high a temperature may affect the long-term stability of the membrane. The preferred temperature is 40-50°C. The feed-side pressure is maintained at the aforementioned 0.3-1.0 MPa, while the permeate-side pressure is maintained at a lower pressure, typically 0-0.1 MPa (absolute pressure), through a back pressure valve. The resulting transmembrane pressure difference (ΔP) is the core driving force for component permeation, preferably ΔP of 0.3-0.7 MPa. Under precisely controlled temperature and pressure conditions, TMS molecules with smaller kinetic diameters can more effectively permeate selectively to the other side of the membrane through the straight channels (approximately 0.55 nm) of the highly b-axis oriented ZSM-5 membrane, while iC5 molecules with slightly larger diameters are significantly retained.

[0068] The main innovative ideas of this invention include:

[0069] (1) Key parameters for membrane preparation:

[0070] Molar ratio of synthesis solution: SiO2:Al2O3:template:H2O=100:1:10-15:2000-3000 (TPAOH template agent is preferred to ensure b-axis orientation);

[0071] Crystallization conditions: Static crystallization at 160-180℃ for 24-48 hours, calcination temperature 550℃;

[0072] Membrane performance: b-axis orientation value ≥ 0.85, separation layer thickness 1-3 μm, membrane flux ≥ 2.0 kg·m -2 ·h -1 .

[0073] (2) Cooperative design of devices:

[0074] The vaporizer and membrane module temperatures are matched (vaporization 40-80℃ / membrane operation 30-60℃) to avoid vapor phase condensation.

[0075] Precise control of transmembrane pressure differential (0.3-0.7 MPa) balances flux and selectivity;

[0076] Multi-tube parallel membrane modules are suitable for large-scale production (processing capacity of 50-500 kg / d).

[0077] Example 1: Purification of TMS using ZSM-5 membrane with b-axis orientation value of 0.85

[0078] Membrane preparation:

[0079] Molar ratio of synthesis solution: SiO2:Al2O3:TPAOH:H2O=100:1:10:2000;

[0080] Crystallization conditions: Static crystallization at 160℃ for 24 hours, followed by calcination at 550℃ for 6 hours;

[0081] Membrane properties: b-axis orientation value 0.85, separation layer thickness 3 μm, XRD measurement I(020) / I(111)=0.85.

[0082] Purification process:

[0083] Crude TMS raw material: 95% purity (containing 55% iC);

[0084] The molecular sieve membrane module was activated under N2 atmosphere by heating to 320°C at 1.5°C / min and holding for 3 hours, and then loaded into the device.

[0085] Preheat the raw materials to 35°C;

[0086] Vaporization temperature 40℃, membrane operating temperature 30℃, transmembrane pressure difference 0.3MPa, feed flow rate 3mL / min;

[0087] Results: TMS purity 99.97%, membrane flux 2.0 kg·m -2 ·h -1 The one-way return rate was 70.2%.

[0088] Example 2: Purification of TMS using ZSM-5 membrane with b-axis orientation value of 0.90

[0089] Membrane preparation:

[0090] Molar ratio of synthesis solution: SiO2:Al2O3:TPAOH:H2O=100:1:12:2500;

[0091] Crystallization conditions: Static crystallization at 170℃ for 36 hours, followed by calcination at 550℃ for 6 hours;

[0092] Membrane properties: b-axis orientation value 0.90, separation layer thickness 2μm, I(020) / I(111)=0.90.

[0093] Purification process:

[0094] Crude TMS raw material: 97% purity (containing 53% iC);

[0095] The molecular sieve membrane module was activated under N2 atmosphere by heating to 320°C at 1.5°C / min and holding for 3 hours, and then loaded into the device.

[0096] Preheat the raw materials to 35°C;

[0097] Vaporization temperature 60℃, membrane operating temperature 45℃, transmembrane pressure difference 0.5MPa, feed flow rate 6mL / min;

[0098] Results: TMS purity 99.99%, membrane flux 3.0 kg·m -2 ·h -1 The one-way return rate was 78.6%.

[0099] Example 3: Purification of TMS using ZSM-5 membrane with b-axis orientation value of 0.95

[0100] Membrane preparation:

[0101] Molar ratio of synthesis solution: SiO2:Al2O3:TPAOH:H2O=100:1:15:3000;

[0102] Crystallization conditions: Static crystallization at 180℃ for 48 hours, calcination at 550℃ for 6 hours;

[0103] Membrane properties: b-axis orientation value 0.95, separation layer thickness 1 μm, I(020) / I(111)=0.95.

[0104] Purification process:

[0105] Crude TMS raw material: 98% purity (containing 2% iC5);

[0106] The molecular sieve membrane module was activated under N2 atmosphere by heating to 320°C at 1.5°C / min and holding for 3 hours, and then loaded into the device.

[0107] Preheat the raw materials to 35°C;

[0108] Vaporization temperature 80℃, membrane operating temperature 60℃, transmembrane pressure difference 0.7MPa, feed flow rate 10mL / min;

[0109] Results: TMS purity 99.996%, membrane flux 2.8 kg·m -2 ·h -1 The one-way return rate is 80.5%.

[0110] Example 4

[0111] Different from Example 1:

[0112] The vaporizer temperature is set to 65℃, and the outlet pressure is controlled at 0.5MPa.

[0113] The membrane module temperature was maintained at 45℃; the feed side pressure was 0.5MPa, and the permeate side pressure was 0.05MPa (the transmembrane pressure difference ΔP was 0.45MPa); the feed flow rate was controlled at 6mL / min.

[0114] Results: The purity of tetramethylsilane in the permeate-side product was 99.95%, the single-pass yield was 78.5%, and the membrane flux was 2.1 kg·m³. -2 ·h -1 .

[0115] Example 5

[0116] Unlike Example 1, this example mainly changes the pressure parameters to explore the effect of high transmembrane pressure difference on separation performance.

[0117] The vaporizer outlet pressure was increased to 0.8 MPa.

[0118] The feed side pressure was maintained at 0.8 MPa, and the permeate side pressure was reduced to 0.02 MPa (increasing the transmembrane pressure difference ΔP to 0.78 MPa); the remaining conditions were the same as in Example 1.

[0119] Results: Under high mass transfer driving force, the purity of tetramethylsilane was significantly improved to 99.993% (reaching the 4N3 level), and the membrane flux increased to 3.0 kg·m³. -2 ·h -1 However, due to a relative decrease in selectivity, the one-way yield dropped slightly to 72.0%.

[0120] Example 6

[0121] Unlike Example 1, this example adjusts both temperature and pressure to seek the optimal balance between purity and yield.

[0122] The vaporization temperature is increased to 70℃, and the outlet pressure is controlled at 0.7MPa.

[0123] The membrane module temperature was increased to 50℃; the feed side pressure was 0.7MPa, and the permeate side pressure was 0.03MPa (ΔP was 0.67MPa); the feed flow rate was increased to 7mL / min.

[0124] Results: Under optimized temperature and pressure synergistic conditions, the purity of tetramethylsilane reached 99.996% (exceeding 4N grade), while the single-pass yield remained at a high level of 80.5%, and the membrane flux was 2.8 kg·m³. -2 ·h -1 It has the best overall performance.

[0125] Comparative Example 1: The difference from Example 2 is as follows:

[0126] Commercially available conventional random-oriented ZSM-5 membrane was selected.

[0127] Membrane properties: b-axis orientation value 0.3, separation layer thickness 3 μm;

[0128] Results: TMS purity 99.5%, membrane flux 1.2 kg·m -2 ·h -1 The yield was 52.1%.

[0129] Comparative Example 2: Traditional Distillation Method

[0130] Equipment: 120-plate theoretical tray distillation column;

[0131] Operating conditions: reflux ratio 15:1, bottom temperature 302K, top temperature 299.5K;

[0132] Results: TMS purity was 99.9%, energy consumption was 2.3 times that of Example 3, and yield was 65.3%.

[0133] Comparative Example 3: Adsorption method, the difference from Example 2 is as follows:

[0134] Process: 13X adsorption column (30℃) → ZSM-5 adsorption column (45℃);

[0135] Operation: Intermittent, 10L crude TMS per batch, adsorption time 4h;

[0136] Results: The purity of the first batch was 99.99%, but after the 10th batch, the purity dropped to 99.9%, making continuous operation impossible.

[0137] Comparative Example 4

[0138] Unlike Example 6, this comparative example mainly changes the membrane module temperature to explore the effect of low temperature on separation selectivity.

[0139] The membrane module temperature was reduced to 35°C; the remaining conditions were the same as in Example 6.

[0140] Results: At lower temperatures, the product purity was 99.98%, indicating a slight improvement in membrane selectivity. However, due to a significant slowdown in molecular diffusion rate, the membrane flux decreased to 1.3 kg·m³. -2 ·h -1 The one-way return rate also decreased to 65.2%.

[0141] The above examples demonstrate that by systematically adjusting key parameters such as vaporization temperature, membrane operating temperature, and transmembrane pressure difference, the purity, yield, and throughput of the separation process can be effectively controlled. Under optimized process conditions (such as in Example 3), the method of this invention can stably obtain tetramethylsilane products with a purity exceeding 99.99%, and the energy consumption is far lower than that of traditional distillation processes.

[0142] This invention discloses a TMS purification device and method based on a highly b-axis oriented ZSM-5 molecular sieve membrane. The device includes a pretreatment component, a vaporization component, a membrane separation component (the core of which is a ZSM-5 membrane module with a b-axis orientation value ≥ 0.85), a condensation and collection component, and a tail gas treatment component. The method achieves continuous purification through "pretreatment-vaporization (40-80℃)-membrane separation (30-60℃, transmembrane pressure difference 0.3-0.7MPa)-condensation". This invention utilizes straight-through channels to reduce mass transfer resistance, achieving a membrane flux ≥ 2.0 kg·m³. -2 ·h -1 The TMS purity reaches up to 99.996%, and the energy consumption is reduced by more than 50% compared with traditional distillation. It solves the purification problem of TMS and iC5 systems with very similar boiling points and is suitable for large-scale production of electronic-grade TMS.

[0143] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0144] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A device for purifying tetramethylsilane (TMS) based on a highly b-axis oriented ZSM-5 zeolite membrane, comprising: a raw material pretreatment assembly including a station for placing a crude TMS containing tank and a precision filter connected to a raw material pipe, the station being provided with a heating device; a vaporization assembly including a vaporizer in communication with the raw material pipe of the raw material pretreatment assembly; a membrane separation assembly including a membrane assembly of a highly b-axis oriented ZSM-5 zeolite membrane, the b-axis orientation value of the ZSM-5 zeolite membrane in the membrane assembly being 0.90-95, the separation layer thickness being 1-3 μm, and the membrane carrier being an α-Al 2 O 3 porous ceramic tube; the inlet of the membrane assembly being in communication with the vaporization outlet of the vaporization assembly; a condensation and collection assembly including a first condenser in communication with a second connecting pipe on the permeation side of the membrane separation assembly, and a product tank in communication with the outlet of the condenser; a tail gas treatment assembly including a tail gas device in communication with a first connecting pipe on the rejection side of the membrane separation assembly; the vaporizer is a vaporizer heated by heat conducting oil, the temperature control precision is ± 1 ℃, the controllable range of the vaporization temperature is 40-80 ℃, and the parameter settings of the membrane separation assembly in the working state include a membrane operating temperature of 30-60 ℃, a transmembrane pressure difference of 0.3-0.7 MPa, and a difference between the vaporization temperature and the membrane operating temperature ≤ 20 ℃. The ZSM-5 zeolite membrane is prepared by a hydrothermal synthesis method, and the preparation steps include: (1) carrier pretreatment: the α-Al 2 O 3 ceramic tube is sequentially immersed in 1 mol / L hydrochloric acid for 2 h, washed with deionized water until neutral, dried at 120 ℃, and then calcined at 550 ℃ for 2 h; (2) seed coating: ZSM-5 seeds are dispersed in ethanol, ultrasonic treatment is performed for 30 min to obtain a seed liquid with a mass concentration of 1%-3%, and the seed liquid is coated on the outer surface of the carrier by an immersion method and dried at 60 ℃; (3) hydrothermal synthesis: the carrier coated with seeds is vertically placed in a reaction kettle, a synthesis solution is added, and static crystallization is performed at 160-180 ℃ for 24-48 h, the molar composition of the synthesis solution including: SiO 2 :Al 2 O 3 :template:H 2 O=100:1:10-15:2000-3000; (4) post-treatment: the carrier after crystallization is taken out, washed with deionized water until pH=7, dried at 120 ℃, and then calcined at 550 ℃ for 6 h to remove the template to obtain a highly b-axis oriented ZSM-5 zeolite membrane. The b-axis orientation value of the ZSM-5 zeolite membrane is determined by X-ray diffraction: the ratio of the diffraction peak intensity I (020) of the (020) crystal face to the diffraction peak intensity I (111) of the (111) crystal face, that is, the orientation value = I (020) / I (111) ≥ 0.

85. The template is selected from: tetrapropylammonium hydroxide, tetrapropylammonium bromide or triethylamine. 6.A TMS purification method based on the device of any one of claims 1-5, comprising the following steps: (1) raw material pretreatment: passing the raw material TMS through the precision filter to obtain pretreated crude TMS; (2) vaporization: sending the pretreated crude TMS into the vaporizer for vaporization to obtain a mixed gas phase of the raw material; ​ ​ 2. The apparatus of claim 1, wherein, ​ ​ ​ ​ ​ 3. The apparatus of claim 1, wherein, The membrane assembly adopts a parallel structure of multiple ceramic tubes, each ceramic tube has a length of 300-500 mm, an inner diameter of 8-12 mm, and an outer diameter of 12-16 mm, and the total membrane area is 0.1-0.5 m 2 .

4. The apparatus of claim 1, wherein, ​ 5. The apparatus of claim 2, wherein, ​ ​ ​ ​ (3) Membrane separation: the mixed gas phase is passed into a membrane module comprising a pretreated highly b-axis oriented ZSM-5 molecular sieve membrane, the membrane operating temperature is controlled at 30-60℃, the transmembrane pressure difference is controlled at 0.3-0.7 MPa, and the TMS molecules pass through the membrane pores to enter the permeation side; (4) Condensation collection: the TMS gas phase on the permeation side is sent into a first condenser to be condensed into a liquid state and collected into a product tank to obtain electronic-grade TMS.

7. The method of claim 6, wherein, The pretreatment in step (3) is: programmed heating at a heating rate of 1-2℃ / min to 300-350℃ and holding for 2-4 hours.

8. The method of claim 6, wherein, The crude TMS in step (2) is further preheated before being sent into the tubular vaporizer, and the preheating is: uniformly raised to 30-40℃ at a rate of 1-5℃ / min.

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