Production system and production method of high-purity disilane

Abstract

The invention discloses a high-purity disilane production system and a high-purity disilane production method. The system comprises a reactor (100), a primary gas-solid separator (200), supercharging equipment (300), a secondary gas-solid separator (400), a gas separation membrane assembly (500), a light component removal tower (600) and a product tower (700) which are sequentially connected through pipelines. The core of the invention lies in that a two-stage gas-solid separation structure is adopted to effectively solve the contradiction between the low-pressure operation of the reactor and the high-pressure feeding of the membrane module, and core equipment is fully protected; meanwhile, a mixed matrix molecular sieve membrane is arranged in the gas separation membrane assembly, and screening of hydrogen and monosilane molecules can be efficiently achieved, so that the reaction byproduct hydrogen is removed through a one-step method. According to the method, monosilane is taken as a raw material, after reaction synthesis, primary dust removal, pressurization, fine dust removal, membrane-method dehydrogenation and rectification separation are sequentially carried out on a product, a high-purity disilane product is finally obtained, and unreacted monosilane is returned to a system for cyclic utilization.

Description

Technical Field This invention belongs to the field of high-purity electronic specialty gas preparation technology, specifically relating to a high-purity silane production system and production method. Background Technology Silane (Si₂H₆), an important electronic specialty gas, has wide applications in the semiconductor industry, especially in advanced processes such as chemical vapor deposition and atomic layer deposition, to form high-quality silicon thin films. Compared with silane (SiH₄), silane has a lower reaction temperature and higher film deposition quality, thus its advantages in high-end chip manufacturing are becoming increasingly prominent.

[0001] Currently, the preparation of silane is mainly achieved through the thermal decomposition reaction of silane (2SiH4 → Si2H6 + H2). This reaction process is accompanied by the generation of byproducts such as hydrogen, propane, and solid silicon powder. Therefore, the efficient and economical separation and purification of silane from the reaction products has become a key technological bottleneck restricting its large-scale production.

[0002] Several separation and purification methods exist in the existing technology, but all of them have significant limitations: First, traditional processes such as cryogenic separation and pressure swing adsorption (PSA) have inherent drawbacks in the crucial step of hydrogen removal. Cryogenic separation has extremely high energy consumption and carries the risk of pipeline blockage; PSA is an intermittent operation with poor system stability and continuity.

[0003] Secondly, although membrane separation technology has been introduced into this field, its efficiency needs improvement. For example, Chinese invention patent CN119218999A discloses a "purification method for silane," employing a process of "filtration and adsorption—de-heavy distillation—membrane separation—de-light distillation." The organic polymer reverse osmosis membrane (such as a nylon membrane) used in this technical solution has a separation mechanism mainly based on the dissolution-diffusion principle, resulting in a low separation factor for hydrogen / silane, leading to incomplete hydrogen removal. This not only increases the load on the downstream distillation unit but also limits further improvement in the purity of the final product. Furthermore, its "distillation first, then membrane separation" process design fails to prioritize the removal of large amounts of hydrogen by the membrane separation unit, resulting in a large volume of gas entering the first distillation system, which inadvertently increases the energy consumption and equipment scale of this process.

[0004] In addition, another technical approach employs a combination of adsorption and distillation. For example, Chinese patent CN119548942A discloses a temperature-switching adsorption (TSA) system for removing light components such as hydrogen. While this type of adsorption process can achieve a certain separation effect, it is essentially an intermittent operation, requiring frequent heating and regeneration of the adsorbent, leading to system instability, frequent valve switching, and high energy consumption. More importantly, the adsorption process may result in the co-adsorption loss of some valuable silane products, and the composition of the outlet gas fluctuates periodically, making the feed conditions for subsequent distillation processes unstable. Ultimately, this makes it difficult to consistently and stably achieve the ultra-high electronic grade standard of over 99.999% purity.

[0005] In summary, existing technologies, whether the inefficient membrane process represented by CN119218999A, the intermittent adsorption process represented by CN119548942A, or the traditional cryogenic and pressure swing adsorption technologies, all suffer from one or more prominent problems such as insufficient separation efficiency, suboptimal process flow, excessive energy consumption, or discontinuous and unstable system operation. These factors collectively limit the efficient, low-cost, and large-scale production of silane.

[0006] Furthermore, existing technical solutions typically employ only a single gas-solid separation stage to handle solid silicon powder in the reaction products. This simplistic approach faces a dilemma when confronted with the conflict between the need for low-pressure reactor operation to suppress side reactions and the requirement for higher inlet pressure for membrane separation to ensure driving force: placing the separator before the compressor results in a significant pressure drop due to the high-precision filter used to protect the compressor, hindering stable reactor operation; placing it after the compressor causes severe wear and damage to the compressor due to solid dust, and considering the involvement of sensitive materials such as silane, hydrogen, and silane, this poses a serious challenge to the stability and safety of system operation. Current technologies have not provided a satisfactory solution to this engineering challenge, thus impacting the reliability and economy of the entire production system.

[0007] Therefore, there is an urgent need in this field for a new high-purity silane production system and process that can systematically resolve the contradictions between reactor protection, pressurization equipment protection, and efficient membrane module separation. Summary of the Invention

[0008] In view of this, the present invention provides a high-purity silane production system and a production method thereof.

[0009] The technical solution provided by this invention is as follows: In a first aspect, the present invention provides a high-purity silane production system, comprising a reactor 100, a primary gas-solid separator 200, a booster device 300, a secondary gas-solid separator 400, a gas separation membrane module 500, a light-weight removal tower 600, and a product tower 700 connected in sequence by pipelines. The reactor 100 is provided with a raw material gas inlet for introducing raw materials containing silane and reacting them at high temperature; the outlet of the reactor 100 is connected to the inlet of a primary gas-solid separator 200, which is used for primary dust removal of the reaction products; it is used to remove most of the solid silicon powder, especially larger particles, from the reaction products. The gas phase outlet of the primary gas-solid separator 200 is connected to the inlet of the booster device 300, which is used to boost the reaction products (gas phase) after primary dust removal. The outlet of the booster device 300 is connected to the inlet of the secondary gas-solid separator 400, which is used to remove dust from the pressurized reaction products. The gas phase outlet of the secondary gas-solid separator 400 is connected to the inlet of the gas separation membrane module 500; the gas separation membrane module 500 is provided with a permeate outlet and a residual permeate outlet, and its residual permeate outlet is connected to the feed inlet of the light-duty removal tower 600; the permeate outlet of the gas separation membrane module is connected to the tail gas system for discharging hydrogen-rich permeate. The gas separation membrane assembly 500 has a molecular sieve membrane inside that can efficiently separate hydrogen and silane; the molecular sieve membrane is a mixed matrix membrane; it is configured to achieve highly selective separation of hydrogen molecules and silane molecules; The molecular sieve membrane comprises a continuous polymer phase and inorganic fillers dispersed therein; The light component outlet is located at the top of the light component removal tower 600, which is connected to the feed inlet of the reactor 100, thereby returning unreacted silane to the reactor for recycling and forming a material circulation loop; the heavy component outlet is located at the bottom of the light component removal tower 600, which is connected to the feed inlet of the product tower 700.

[0010] Product column 700 is used to separate high-purity ethylsilane from heavy components. It has a high-purity ethylsilane product outlet at the top and a by-product outlet at the bottom for collecting by-products containing propane.

[0011] The material of the continuous phase of the polymer is selected from at least one of polyimide, cellulose ester, polysulfone, polyethersulfone, polycarbonate, and polydimethylsiloxane.

[0012] The inorganic filler is selected from at least one of zeolite molecular sieves, metal-organic framework materials, carbon molecular sieves, and silica nanoparticles.

[0013] Preferably, the inorganic filler is a zeolite molecular sieve and a metal-organic framework material (such as ZIF-8); and the mass ratio of the two is 1:1-2:1. By constructing a hybrid filler phase that simultaneously possesses the dual characteristics of "zeolite precision sieving" and "MOF rapid mass transfer", key problems such as the difficulty in achieving both permeability and selectivity in molecular sieve membranes (mixed matrix membranes) and the tendency of filler to agglomerate and generate defects are synergistically solved.

[0014] The effective separation pore size of the molecular sieve membrane is between the kinetic diameters of hydrogen molecules and silane molecules, and its average pore size is 0.3 nm to 0.4 nm.

[0015] Preferably, the molecular sieve membrane has a pore size distribution with a single peak and a half-peak width of no more than 0.05 nm.

[0016] Preferably, the gas separation membrane assembly has a separation factor of not less than 100 for H2 / SiH4 mixed gas and a permeation rate of not less than 100 GPU for hydrogen gas under the conditions of 25°C and 0.6 MPa.

[0017] In the molecular sieve membrane, the mass fraction of the inorganic filler is 15% to 35%.

[0018] The primary gas-solid separator 200 is a cyclone separator or a gravity settling device.

[0019] The secondary gas-solid separator 300 is a sintered metal filter or a ceramic filter.

[0020] The booster device 300 is a diaphragm compressor, and its outlet pressure is configured to be between 0.5 MPa and 1.0 MPa.

[0021] Secondly, the present invention also provides a method for preparing high-purity silane using the aforementioned high-purity silane production system, comprising the following steps: S1. The raw material containing silane is fed into reactor 100 to react and generate a product containing silane, propane, hydrogen and solid silicon powder; the product enters the primary gas-solid separator 200 for primary dust removal. S2. The gaseous product after primary dust removal in step S1 is pressurized by the booster 300 and then filtered by the secondary gas-solid separator 400 to further remove solid particles. S3. Membrane dehydrogenation: The gas phase component obtained in step S2 is fed into the gas separation membrane module 500. Under the pressure difference across the membrane, hydrogen is removed as permeate and discharged to the tail gas system. The residual gas is a component rich in silane. S4. Distillation and separation: The permeate obtained in step S3 is passed into the light component removal tower 600 for separation. The unreacted silane-containing raw material collected from the light component outlet at the top of the tower is returned to the reactor 100 for recycling. The heavy component collected from the heavy component outlet at the bottom of the tower enters the product tower 700. In the product tower 700, high-purity silane product is collected from the top of the tower, and by-product containing propane is collected from the bottom of the tower.

[0022] In step S1, the reaction temperature is 420~520℃ and the reaction pressure is 1.0~3.0 bar.

[0023] The volume fraction of silane in the raw materials containing silane is 60% to 100%.

[0024] The core of this invention lies in its two-stage gas-solid separation architecture, which effectively resolves the conflict between low-pressure operation of the reactor and high-pressure feeding of the membrane module, while fully protecting the core equipment. Simultaneously, the gas separation membrane module incorporates a mixed-matrix molecular sieve membrane, enabling efficient sieving of hydrogen and silane molecules, thus removing the reaction byproduct hydrogen in a one-step process. Using silane as a raw material, this invention, after reaction synthesis, sequentially performs primary dust removal, pressurization, fine dust removal, membrane dehydrogenation, and distillation separation to ultimately obtain high-purity silane. Unreacted silane is returned to the system for recycling.

[0025] Compared with the prior art, the present invention has the following significant advantages: (1) The present invention adopts a two-stage gas-solid separation architecture of “primary dust removal-compression-fine dust removal”. This design protects the low-pressure operating environment of the reactor through the primary separator with low pressure drop, protects the pressurization equipment through the pre-coarse dust removal, and provides ultimate protection for the membrane module through the post-fine dust removal, fundamentally solving the engineering contradictions faced by the traditional single-stage separation process and greatly improving the reliability and life of the system.

[0026] (2) By employing a mixed matrix molecular sieve membrane with specific pore size and narrow pore size distribution, this invention achieves highly selective sieving of hydrogen / silane (separation factor ≥ 100), far exceeding the level of reverse osmosis membranes in the prior art (approximately 20). This makes hydrogen removal more thorough, greatly reducing the separation difficulty of downstream distillation units and providing a key guarantee for the stable acquisition of high-purity silane products with a purity of over 99.999%.

[0027] (3) The present invention adopts a process of “membrane separation for dehydrogenation followed by distillation for purification”. This process utilizes membrane separation to efficiently remove a large amount of hydrogen at room temperature, which significantly reduces the total amount of material entering the distillation system, especially the content of light components. In particular, it eliminates the adverse effects of a large amount of hydrogen on the operation of the distillation column, thereby greatly reducing the energy consumption and equipment investment of cryogenic distillation.

[0028] (4) This invention organically combines reaction, membrane separation, distillation and material recycling into a whole system. By returning the unreacted silane from the top of the light-removal tower to the reactor, the raw materials are recycled, the atom economy is improved, and the raw material consumption is reduced, thus making the whole production process greener and more economical.

[0029] (5) Membrane separation is a continuous and stable physical process without intermittent operations such as adsorbent regeneration. It is perfectly matched with continuous distillation process, ensuring the continuity and stability of system operation. It is very suitable for large-scale, industrial production of electronic-grade high-purity gas. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or existing methods and experiments, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a process flow diagram for the production of silane.

[0032] Explanation of reference numerals in the attached drawings: 100-reactor; 200-primary gas-solid separator; 300-pressurization equipment; 400-secondary gas-solid separator; 500-gas separation membrane module; 600-light weight removal tower; 700-product tower. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto. Those skilled in the art should understand that various modifications and changes can be made without departing from the spirit and scope of the present invention.

[0034] This invention provides a high-purity silane production system, the schematic diagram of which is shown below. Figure 1 As shown, it includes a reactor 100, a primary gas-solid separator 200, a pressurizing device 300, a secondary gas-solid separator 400, a gas separation membrane module 500, a light-weight removal tower 600, and a product tower 700, which are connected in sequence by pipelines.

[0035] The reactor 100 is equipped with a raw material gas inlet for introducing raw materials containing silane and reacting them at high temperature. The outlet of the reactor 100 is connected to the inlet of a primary gas-solid separator 200, which is used to remove most of the solid silicon powder, especially larger particles, from the reaction products and to perform primary dust removal on the reaction products.

[0036] The gas phase outlet of the primary gas-solid separator 200 is connected to the inlet of the booster device 300, which is used to boost the reaction products (gas phase) after primary dust removal. The outlet of the booster device 300 is connected to the inlet of the secondary gas-solid separator 400, which is used to remove dust from the pressurized reaction products. The gas phase outlet of the secondary gas-solid separator 400 is connected to the inlet of the gas separation membrane module 500. The gas separation membrane module 500 is provided with a permeate outlet and a residual permeate outlet. The residual permeate outlet is connected to the feed inlet of the light-duty removal tower 600. The permeate outlet of the gas separation membrane module is connected to the tail gas system for discharging hydrogen-rich permeate.

[0037] The gas separation membrane assembly 500 has a molecular sieve membrane inside that can efficiently separate hydrogen and silane; the molecular sieve membrane is a mixed matrix membrane; it is configured to achieve highly selective separation of hydrogen molecules and silane molecules.

[0038] The molecular sieve membrane comprises a continuous polymer phase and inorganic fillers dispersed therein.

[0039] The material of the continuous phase of the polymer is selected from at least one of polyimide, cellulose ester, polysulfone, polyethersulfone, polycarbonate, and polydimethylsiloxane.

[0040] The inorganic filler is selected from at least one of zeolite molecular sieves, metal-organic framework materials, carbon molecular sieves, and silica nanoparticles.

[0041] The effective separation pore size of the molecular sieve membrane is between the kinetic diameters of hydrogen molecules and silane molecules, and its average pore size is 0.3 nm to 0.4 nm.

[0042] Preferably, the molecular sieve membrane has a pore size distribution with a single peak and a half-peak width of no more than 0.05 nm.

[0043] Preferably, the gas separation membrane assembly has a separation factor of not less than 100 for H2 / SiH4 mixed gas and a permeation rate of not less than 100 GPU for hydrogen gas under the conditions of 25°C and 0.6 MPa.

[0044] The light component outlet is located at the top of the light component removal tower 600, which is connected to the feed inlet of the reactor 100, thereby returning unreacted silane to the reactor for recycling and forming a material circulation loop; the heavy component outlet is located at the bottom of the light component removal tower 600, which is connected to the feed inlet of the product tower 700.

[0045] Product column 700 is used to separate high-purity ethylsilane from heavy components. It has a high-purity ethylsilane product outlet at the top and a by-product outlet at the bottom for collecting by-products containing propane.

[0046] The working principle of the high-purity silane production system is as follows: The silane-containing raw material enters reactor 100 for thermal reaction. The resulting product enters primary gas-solid separator 200 for initial dust removal. The resulting gaseous component enters pressurization equipment 300 for further pressurization. The pressurized material then enters secondary gas-solid separator 400 for fine dust removal. The resulting gaseous component enters gas separation membrane module 500, where hydrogen-rich permeate gas is separated, achieving efficient removal of hydrogen from the reaction product. The dehydrogenated permeate gas enters light component removal tower 600. The silane-containing light component collected from the top of the tower is returned to reactor 100 for recycling, while the heavy component from the bottom of the tower enters product tower 700 for final separation. High-purity silane product is obtained at the outlet; a by-product containing propane is collected at the outlet.

[0047] The gas separation membrane assembly 500 includes a mixed matrix membrane comprising a polymer continuous phase and an inorganic filler dispersed therein. The polymer continuous phase is polyimide or polydimethylsiloxane; the inorganic filler is MFI-type zeolite molecular sieve and / or ZIF-8 nanoparticles.

[0048] A process for producing high-purity silane includes the following steps: S1. Reaction and Primary Dust Removal: The raw material containing silane enters reactor 100 and reacts under the action of a thermal field at a temperature of 420~520℃ and a pressure of 1.0~3.0 bar to generate a product containing silane, propane, hydrogen and solid silicon powder. This product first enters the primary gas-solid separator 200 for primary dust removal to remove most of the solid silicon powder. S2, Pressurization and fine dust removal: The product from step S1 is pressurized by pressurization equipment 300 and then sent to secondary gas-solid separator 400 for fine filtration to further remove solid particles. S3. Membrane dehydrogenation: The gas phase component obtained in step S2 is fed into the gas separation membrane module 500. Driven by the pressure difference across the membrane, hydrogen is efficiently removed as permeate and discharged to the tail gas system. The residual gas is a component rich in silane. The recovery rate of hydrogen from the permeate is not less than 90%, and the recovery rate of silane from the residual gas is not less than 90%.

[0049] S4. Distillation and separation: The residual gas obtained in step S3 is first passed into the light gas removal tower 600 for separation. The unreacted silane collected from the top of the tower is returned to the inlet of reactor 100 in step S1 for recycling, and the heavy components collected from the bottom of the tower enter the product tower 700. In the product tower 700, high-purity silane product with a purity of not less than 99.999% is collected from the top of the tower, and by-products containing propane are collected from the bottom of the tower.

[0050] Example 1 In this embodiment, the gas separation membrane module 500 uses MFI type zeolite molecular sieve (average particle size 200 nm) as inorganic filler.

[0051] 1. System Configuration Reactor 100: A tubular reactor equipped with an electric heating element.

[0052] The primary gas-solid separator uses a cyclone separator 200, and its operating pressure drop is designed to be less than 3 kPa.

[0053] Boosting equipment 300: It adopts a diaphragm compressor to boost gaseous materials, and its outlet pressure is set to 0.7 MPa.

[0054] Secondary gas-solid separator 400: It uses a sintered metal filter with a filtration accuracy of 0.5 microns to perform fine dust removal on the pressurized gas phase.

[0055] Gas separation membrane module 500: It is equipped with a hollow fiber mixed matrix membrane; the mixed matrix membrane uses polyimide as the polymer continuous phase and MFI type zeolite molecular sieve (average particle size 200 nm) as inorganic filler, with a filler mass fraction of 25%.

[0056] Distillation columns: Both the light component removal column 600 and the product column 700 are packed columns, filled with stainless steel wire mesh corrugated packing.

[0057] 2. Membrane performance characterization Performance tests were conducted on the mixed matrix membrane used in the gas separation membrane module 500. The results showed that its average pore size was approximately 0.35 nm, the pore size distribution exhibited a single peak, and the full width at half maximum (FWHM) was approximately 0.04 nm. Under test conditions of 25 °C and 0.6 MPa, the separation factor for the simulated feed gas (H2 / SiH4 volume ratio 5 / 95) reached as high as 150, and the hydrogen permeation rate was 120 GPU.

[0058] 3. Production Process and Results The specific production process and its effects are as follows: A raw material with a silane volume fraction of 90% is fed into reactor 100, and the reaction is carried out at a reaction temperature of 480℃ and a pressure of 1.5 bar (absolute pressure). The reaction product is first passed through a cyclone separator primary gas-solid separator 200 to remove >90% of solid silicon powder. The resulting gas phase enters a diaphragm-type pressurization device 300 to be pressurized to 0.7 MPa, and then passes through a sintered metal filter secondary gas-solid separator 400 for fine filtration to completely remove residual dust, resulting in a clean gas phase component. This clean component enters a gas separation membrane module 500. After membrane separation, the recovery rate of hydrogen on the permeate side of the gas separation membrane module reaches 95%, and the recovery rate of silane on the permeate side reaches 98%.

[0059] The permeate enters the light component removal tower 600, and the light component rich in silane collected from the top of the tower is returned to reactor 100 for recycling. The heavy component at the bottom of the light component removal tower 600 enters the product tower 700 for final separation.

[0060] Finally, high-purity silane was obtained from the top of the product column at 700°C, with a purity ≥ 99.9995%. Chromatographic analysis showed that the content of impurities such as silane, hydrogen, and propane in this product was all below 0.5 ppm.

[0061] Example 2: Hybrid matrix membrane using MOFs filler 1. System Configuration The system configuration in this embodiment differs from that in Embodiment 1 in that the gas separation membrane assembly is different; the gas separation membrane assembly 500: adopts an internally mounted spiral wound membrane element; the mixed matrix membrane uses polydimethylsiloxane as the polymer continuous phase and ZIF-8 nanoparticles as the inorganic filler, with a filler mass fraction of 30%.

[0062] The remaining components are the same as in Example 1.

[0063] 2. Membrane performance characterization Tests showed that the average pore size of the membrane was approximately 0.33 nm, and the full width at half maximum (FWHM) was approximately 0.045 nm. Under the same test conditions, the separation factor for H2 / SiH4 was 130, and the hydrogen permeation rate was 150 GPU.

[0064] 3. Production process and results The reactant is 85% by volume silane, the reaction temperature is 450℃, and the pressure is 2.0 bar; The membrane module achieved a 93% hydrogen recovery rate on the permeate side and a 96% silane recovery rate on the reflux side. The final silane product has a purity of ≥99.999%, and the content of each key impurity is less than 1 ppm.

[0065] Example 3 1. System Configuration The difference between the system configuration in this embodiment and that in embodiment 2 is that the inorganic filler is nano-sized ZIF-8 zeolite molecular sieve and MOF-5 type metal-organic framework material; and the mass ratio of the two is 1:1.

[0066] The remaining components are the same as in Example 2.

[0067] 2. Membrane performance characterization Tests showed that the average pore size of the membrane was approximately 0.37 nm, and the full width at half maximum (FWHM) was approximately 0.037 nm. Under the same test conditions, the separation factor for H2 / SiH4 was 150, and the hydrogen permeation rate was 150 GPU.

[0068] 3. Production process and results The reactant is 100% silane by volume, the reaction temperature is 460℃, and the pressure is 1.3 bar. The membrane module achieves a 96% hydrogen recovery rate on the permeate side and a 99% silane recovery rate on the reflux side. The final silane product has a purity of ≥99.999%, and the content of each key impurity is less than 1 ppm.

[0069] ZIF-8 zeolite molecular sieves provide precise pore sizes for molecular sieving, while the channel structure of MOF-5 accelerates hydrogen molecule diffusion; together, they synergistically enhance separation performance.

[0070] Comparative Example 1: Reverse osmosis membrane using existing technology System process: The process is similar to that in CN119218999A, namely "filtration and adsorption - heavy removal distillation - membrane separation - light removal distillation".

[0071] Membrane module: Nylon-6 reverse osmosis membrane is used, and its separation mechanism is dissolution-diffusion with no molecular sieving effect.

[0072] Process effect: Under the same feed conditions, the separation factor of this nylon membrane for H2 / SiH4 is only 22. To achieve similar product purity, the reflux ratio of the light-light removal tower needs to be increased to 15, resulting in a total system energy consumption that is about 35% higher than that of Example 1 of this invention, and the residual hydrogen content in the product fluctuates significantly.

[0073] Comparative Example 2: Membrane-free pure distillation process System process: Only the traditional process route of "reaction - dust removal - multi-stage cryogenic distillation" is adopted.

[0074] Process Effects: To separate H2 (-252℃), SiH4 (-112℃), and Si2H6 (-15℃) with similar boiling points, the materials need to be deeply cooled to below -150℃, and a multi-tower process is required. The equipment investment for this process is about 50% higher than that of this invention, and the operating energy consumption is more than 80% higher. Furthermore, due to the risk of solid precipitation, the operational stability is poor.

[0075] Comparative Example 3 employs a process of compression followed by single-stage filtration and temperature-switching adsorption dehydrogenation (simulating CN119548942A). This comparative simulation demonstrates an existing technical approach that combines "compression followed by filtration" with "temperature-switching adsorption dehydrogenation".

[0076] System flow: The process follows the sequence of "reactor → compressor → single-stage gas-solid separator (sintered metal filter) → temperature-switched adsorption system → light-light-weight removal tower → product tower". This process places compression before filtration and uses temperature-switched adsorption (TSA) instead of membrane separation for dehydrogenation.

[0077] Adsorption system: Two parallel adsorption towers are set up, filled with 5A molecular sieve as adsorbent, to adsorb and remove light components such as hydrogen at room temperature and 0.7MPa. Each adsorption tower is switched after running for 30 minutes and regenerated by heating to 150℃ and purging with inert gas.

[0078] Craftsmanship effect: 1) It causes serious damage to the compressor. The large amount of hard silicon powder carried by the reaction products directly enters the compressor, causing rapid wear of its internal components (such as diaphragms and valve plates), significantly shortening the maintenance cycle and resulting in poor operational reliability. 2) All dust is concentrated in a single precision filter, resulting in a rapid increase in pressure drop and frequent replacements. At the same time, fine dust may penetrate the filter and contaminate the downstream adsorbent, reducing its adsorption capacity and regeneration efficiency.

[0079] 3) The separation process is intermittent and unstable. The periodic switching of the adsorption tower causes fluctuations in the pressure and flow of the entire system, making it impossible to achieve truly continuous and stable production. Product purity is difficult to maintain consistently above 99.999%.

[0080] 4) High energy consumption and material loss: The adsorbent regeneration process requires a large amount of energy for heating and purging, which also leads to the loss of some valuable silane products due to entrainment in the purging gas. Calculations show that the total energy consumption of the system in this comparative example is about 30% higher than that of Example 1 of this invention, and the single-pass loss rate of silane is more than 2% higher.

[0081] Through a comprehensive comparison of the above embodiments with Comparative Examples 1-3, the technological leap brought about by the present invention can be clearly seen: (1) The original two-stage architecture of "primary dust removal - compression - fine dust removal" perfectly solves the engineering contradiction between the low-pressure environment of the reactor, compressor protection and efficient operation of the membrane module. Compared with the defective process of "compression first and then single-stage filtration" in Comparative Example 3, the present invention fundamentally eliminates the damage of dust to the pressurization equipment (compressor), and greatly extends the service life of the fine filter by the graded treatment of dust, ensuring that the system can operate continuously and stably for a long period of time.

[0082] (2) By employing a mixed matrix membrane with molecular sieving effect, the present invention achieves efficient (separation factor ≥ 100), continuous, and stable separation of hydrogen / silane. This completely overcomes the inherent defects of the inefficient membrane method (separation factor ≈ 20) in Comparative Example 1 and the temperature-switching adsorption process in Comparative Example 3—namely, intermittent operation, unstable operation, high regeneration energy consumption, and material loss.

[0083] (3) The optimized “membrane first, distillation later” continuous process, combined with efficient membrane separation, reduces the total energy consumption of the system by 80% compared with the traditional cryogenic process (Comparative Example 2), by more than 30% compared with the existing inefficient membrane process (Comparative Example 1), and by 30% compared with the adsorption regeneration process (Comparative Example 3), while also reducing material loss.

[0084] (4) The efficient pre-dehydrogenation and perfect two-stage dust removal provide pure and stable feed conditions for the distillation unit, so that the product purity can stably reach 99.999% (5N) or even 99.9995% (5.5N) electronic grade ultra-high purity, which completely solves the problem of purity fluctuation and decline caused by incomplete separation, discontinuous operation or unstable equipment in Comparative Examples 1 and 3.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-purity silane production system, characterized in that, It includes a reactor (100), a primary gas-solid separator (200), a booster (300), a secondary gas-solid separator (400), a gas separation membrane module (500), a light-weight removal tower (600), and a product tower (700) connected in sequence by pipelines. The gas separation membrane module (500) is provided with a permeate outlet and a residual gas outlet. The residual gas outlet is connected to the feed inlet of the light gas removal tower (600). The permeate outlet is connected to the tail gas system. The top of the light component removal tower (600) is provided with a light component outlet, which is connected to the raw material inlet of the reactor (100) to form a material circulation loop. The bottom of the light component removal tower (600) is provided with a heavy component outlet, which is connected to the feed inlet of the product tower (700); The product tower (700) is provided with a high-purity silane product outlet at the top and a by-product outlet at the bottom. The gas separation membrane assembly (500) has a molecular sieve membrane inside, which includes a continuous polymer phase and inorganic fillers dispersed therein.

2. The high-purity silane production system according to claim 1, characterized in that, The molecular sieve membrane has an average pore size of 0.3 nm to 0.4 nm.

3. The high-purity silane production system according to claim 1, characterized in that, In the molecular sieve membrane, the mass fraction of the inorganic filler is 15% to 35%.

4. The high-purity silane production system according to claim 3, characterized in that, The polymer continuous phase is selected from at least one of polyimide, cellulose ester, polysulfone, polyethersulfone, polycarbonate, and polydimethylsiloxane; the inorganic filler is selected from at least one of zeolite molecular sieve, metal-organic framework material, carbon molecular sieve, and silica nanoparticles.

5. The high-purity silane production system according to claim 1, characterized in that, The primary gas-solid separator (200) is a cyclone separator or a gravity settling device.

6. The high-purity silane production system according to claim 1, characterized in that, The secondary gas-solid separator (400) is a sintered metal filter or a ceramic filter.

7. The high-purity silane production system according to claim 1, characterized in that, The booster device (300) is a diaphragm compressor with an outlet pressure configured to be between 0.5 MPa and 1.0 MPa.

8. A method for preparing high-purity silane using the high-purity silane production system according to any one of claims 1-7, characterized in that, Includes the following steps: S1. The raw material containing silane is fed into the reactor (100) to react and generate a product containing silane, propane, hydrogen and solid silicon powder; the product enters the primary gas-solid separator (200) for primary dust removal. S2. After the gaseous product from the primary dust removal in step S1 is pressurized by the pressurizing device (300), it enters the secondary gas-solid separator (400) for filtration to further remove solid particles. S3, Membrane dehydrogenation: The gas phase component obtained in step S2 is fed into the gas separation membrane module (500). Under the pressure difference across the membrane, hydrogen is removed as permeate and discharged to the tail gas system. The residual gas is a component rich in silane. S4. Distillation and separation: The residual gas obtained in step S3 is passed into the light component removal tower (600) for separation. The unreacted silane-containing raw material collected from the light component outlet at the top of the tower is returned to the reactor (100) for recycling. The heavy component collected from the heavy component outlet at the bottom of the tower enters the product tower (700). In the product tower (700), high-purity silane product is collected from the top of the tower, and by-product containing propane is collected from the bottom of the tower.

9. The method according to claim 8, characterized in that, In step S1, the reaction temperature is 420~520℃ and the reaction pressure is 1.0~3.0 bar.

10. The method according to claim 8, characterized in that, The volume fraction of silane in the raw materials containing silane is 60% to 100%.

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