Electronic-grade silane gas continuous production and preparation system and production process

Abstract

The electronic-grade silane gas continuous production preparation system comprises a cold hydrogenation treatment device, an inlet of the cold hydrogenation treatment device is connected with a raw material supply system, and an outlet of the cold hydrogenation treatment device is connected with a cold hydrogenation rectifying tower through a pipeline. The cold hydrogenation rectifying tower is sequentially connected with the boron and phosphorus removal adsorption column, the first-stage disproportionator, the first tower, the second tower, the second-stage disproportionator, the third tower and the fourth tower through pipelines, and electronic-grade silane in the fourth tower is used for being conveyed to a silane tank area; the first tower is used for removing silicon tetrachloride produced after the disproportionation reaction of the first-stage disproportionator; the second tower is used for separating the extracted chlorosilane material; the third tower is used for separating silane from chlorosilane; and the fourth tower is used for discharging light impurities and heavy impurities and conveying gas-phase electronic-grade silane into a silane tank area. The device and the method realize continuous, efficient and high-purity production of the electronic-grade silane gas, and have the advantages of low energy consumption, low cost, thorough impurity removal and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of silane production, and in particular relates to a continuous production and preparation system and a production process for electronic-grade silane gas. Background Art

[0002] Silane (SiH4) is a colorless, highly reactive, compressible gas at room temperature and pressure. It can be used to manufacture a range of silicon-containing materials, including high-purity polycrystalline silicon, single crystal silicon, amorphous silicon, metal silicides, silicon nitride, silicon carbide, and silicon oxide. Due to its high purity and ability to achieve precise control, it has become an important specialty gas that cannot be replaced by other silicon sources. Its application is widely used in the microelectronics industry and is gradually expanding to various fields, including steel, machinery, chemicals, and optics.

[0003] With the continuous advancement of the chemical industry, the application scope of silane has continued to expand. It is now used in the manufacture of advanced ceramics, composite materials, functional materials, biomaterials, and high-energy materials, laying the foundation for the development of numerous new technologies, new materials, and new devices. In particular, with the rapid development of the domestic semiconductor and photovoltaic industries, the demand for high-purity silane is rapidly increasing.

[0004] Traditional silane gas production processes primarily include the silicon-magnesium alloy method (also known as the Komatsu method), the sodium aluminum hydride method, and the chlorosilane disproportionation method. Among these, the trichlorosilane disproportionation method is widely used due to its readily available raw materials, low production costs, low energy consumption, and high conversion rate. However, existing disproportionation methods still have limitations in terms of reaction rate, yield, and energy consumption, making them difficult to meet the demands of large-scale applications. Furthermore, existing distillation purification technologies face bottlenecks in impurity removal, making it difficult to achieve purity standards of 6N and above. Existing silane gas production processes are generally plagued by high energy consumption, low efficiency, and insufficient purity, hindering their further adoption in high-end applications.

[0005] Therefore, there is an urgent need for a low-energy, high-efficiency, high-purity silane gas preparation technology to achieve large-scale continuous production of electronic-grade silane gas. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a continuous production and preparation system and production process for electronic-grade silane gas, so as to realize the continuous, efficient and high-purity production of electronic-grade silane gas, and have the advantages of low energy consumption, low cost and thorough impurity removal. At the same time, through the unique boron and phosphorus removal adsorption column structure and step-by-step flushing process, the filler cleaning effect is improved and the recycling of boron and phosphorus resources is facilitated.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: A continuous production and preparation system for electronic-grade silane gas includes a cold hydrotreating device, wherein the inlet of the cold hydrotreating device is connected to a raw material supply system, the outlet of the cold hydrotreating device is connected to a cold hydrodistillation tower via a pipeline, the cold hydrodistillation tower is sequentially connected to a boron and phosphorus removal adsorption column, a primary disproportionator, a first tower, a second tower, a secondary disproportionator, a third tower, and a fourth tower via pipelines, and the electronic-grade silane in the fourth tower is transported to a silane tank area; One tower is used to remove silicon tetrachloride produced after the disproportionation reaction in the first-stage disproportionator; The second tower is used to separate the extracted chlorosilane materials; Three towers are used to separate silane and chlorosilane; The four towers are used to discharge light impurities and heavy impurities, and transport gaseous electronic grade silane into the silane tank area. Preferably, a silicon tetrachloride removal pipeline is provided at the bottom of a tower for conveying silicon tetrachloride to the anti-disproportionation tower of the cold hydrodistillation tower to generate trichlorosilane, and then the trichlorosilane and part of the unreacted silicon tetrachloride are sent to the crude distillation tower in the cold hydrotreatment device for separation, silicon tetrachloride, and trichlorosilane enter the cold hydrodistillation tower for further purification.

[0008] Preferably, the trichlorosilane in the second tower kettle is connected to the first disproportionator kettle via a pipeline.

[0009] Preferably, the kettle of the third tower is connected to the second tower via a pipeline for outputting unreacted chlorosilane to the second tower.

[0010] Preferably, the crude gaseous silane extracted from the top of the three towers enters the silane adsorption column for adsorption and impurity removal and then output to the four towers; the accident tail gas extracted from the top of the three towers is used to be output to the flare.

[0011] Preferably, the top and bottom of the four towers are intermittently discharged with light and heavy silane impurities, respectively, and the gaseous silane products are taken out from the sides of the four towers and sent to the silane tank area after condensation.

[0012] Preferably, the liquid silane in the silane tank area is vaporized and then sent to the silane filling system through a pipeline; the accident tail gas from the silane filling system and the silane tank area is output to the flare.

[0013] Preferably, the boron and phosphorus removal adsorption column comprises a column, a central grid cylinder is provided in the middle of the column, a plurality of grid partitions are provided on the inner wall of the column from bottom to top, the plurality of grid partitions divide the column into three packing layers, and the three packing layers are respectively boron adsorption filler, phosphorus adsorption filler and chelate resin filler from bottom to top; A cleaning component is provided in the central grid cylinder, and the cleaning component is used to clean the three filler layers.

[0014] Preferably, the cleaning assembly includes a cleaning main pipe, on which a plurality of cleaning nozzles are provided; At least two soft partition plates are provided on the cleaning main pipe, and the soft partition plates are located at the junction of the two packing layers; The cleaning main pipeline is equipped with multiple switch valves, which are located at the junction of two packing layers; A concave positioning groove is provided at the bottom of the cleaning main pipeline, the concave positioning groove is adapted to the positioning cone, the positioning cone is provided with a through hole and is used to form a passage with the concave positioning groove; the positioning cone is connected to the cleaning liquid inlet pipeline; A cleaning liquid branch pipe and a purge branch pipe are provided on the cleaning liquid inlet pipeline.

[0015] A production process for a continuous production and preparation system for electronic-grade silane gas, comprising the following methods: S1. Raw material supply: Raw material tanks store hydrogen, silicon powder, silicon tetrachloride, trichlorosilane, and other raw materials, which are stably and continuously transported to the cold hydrotreating unit via pipelines and pumps. S2. Cold hydrogenation and distillation: The cold hydrogenation unit hydrogenates the raw material to produce crude trichlorosilane, which enters the cold hydrogenation distillation tower for distillation and purification. S3. Boron and phosphorus impurity removal: After being purified by the cold hydrogenation distillation column, trichlorosilane enters the boron and phosphorus removal adsorption column and passes through the boron adsorption packing, phosphorus adsorption packing and chelating resin packing set from bottom to top to remove boron, phosphorus impurities and residual trace boron and phosphorus impurities respectively; S4. Disproportionation reaction: After the removal of boron and phosphorus impurities, trichlorosilane is sent to a primary disproportionator for disproportionation reaction. The material after the primary disproportionation reaction enters the first tower; the chlorosilane material without silicon tetrachloride is produced from the top of the first tower and enters the second tower; the trichlorosilane produced from the kettle of the second tower is returned to the primary disproportionator for further reaction, and the chlorosilane material produced from the top of the tower is sent to the secondary disproportionator for further reaction; S5. Multi-stage distillation separation: S5.1 The material after the primary disproportionation reaction enters the first tower, which removes the silicon tetrachloride produced after the reaction. The silicon tetrachloride produced from the bottom of the tower is sent to cold hydrodistillation, and the material produced from the top of the tower enters the second tower; S5.2 The second tower separates the chlorosilane material. The trichlorosilane produced from the bottom of the tower is returned to the first disproportionator, and the material produced from the top of the tower enters the second disproportionator. S5.3 The material after the secondary disproportionation reaction enters the third tower, which separates silane and chlorosilane. The unreacted chlorosilane is withdrawn from the bottom of the tower and returned to the second tower. The crude gaseous silane withdrawn from the top of the tower enters the silane adsorption column. S5.4 After the crude silane is removed from the silane adsorption column, it enters the four-column tower. The four-column tower intermittently discharges silane light and heavy impurities from the top and bottom of the tower. The gaseous silane product produced by the side sampling is condensed and sent to the silane tank area; S6. Tail gas treatment: Chlorosilane and silane waste gases generated during the reaction are sent to the leaching system for treatment; waste gases from silane accidents and emergencies are sent to a flare for incineration; S7. Product filling: Liquid silane in the silane tank area is vaporized and transported via pipelines to the silane filling system. S8. Cleaning the adsorption column: When the boron and phosphorus removal adsorption column filler is saturated, clean it according to the following steps: S8.1 Close the on-off valve between the boron adsorption packing and the phosphorus adsorption packing, and pass an acidic solution to clean the boron adsorption packing to desorb boron from the packing surface; S8.2 Introduce nitrogen to flush away the residual acid solution; S8.3 Close the on-off valve between the chelating resin packing and the phosphorus adsorption packing, open the on-off valve between the boron adsorption packing and the phosphorus adsorption packing, and introduce a non-alkaline cleaning agent (such as a specific complexing agent or a neutral buffer solution) to desorb phosphorus impurities by changing the surface charge properties of the packing or dissolving some of the precipitate; S8.4 Introduce nitrogen to flush away any residual non-alkaline cleaning agent; S8.5 Open all the switch valves and flush the three packing layers together to restore the adsorption performance of the packing.

[0016] The present invention can achieve the following beneficial effects: 1. The entire production process has achieved continuous operation, which has improved production efficiency and reduced production costs.

[0017] 2. High purification efficiency: Through the automated control system and distillation filler technology, the silane purification efficiency is significantly improved, ensuring that the silane purity reaches 6N (≥99.9999%) and above.

[0018] 3. Low energy consumption: The separation and purification system adopts a differential pressure thermal coupling process and designs a heat exchange network between the reactor and the distillation tower to achieve efficient heat utilization. This reduces the energy consumption required for material separation and improves production economics.

[0019] 4. A waste heat recovery system is installed at the reactor outlet and the top of the distillation tower to reuse the waste heat for preheating the feed and improve energy utilization.

[0020] 5. The adsorption purification system uses chelating resin to deeply adsorb trace impurities, effectively solving the bottleneck problem of traditional distillation that is difficult to remove trace impurities.

[0021] 6. Specific cleaning solutions are used to account for the differences in the adsorption mechanisms of boron and phosphorus impurities on different fillers. For example, boron-adsorbing fillers are first cleaned with an acidic solution, using the acid-base reaction to dissolve the metal hydroxide complexed with the borate ion, precisely desorbing the boron impurities. Phosphorus-adsorbing fillers are then cleaned with a non-alkaline detergent, which effectively desorbs phosphorus impurities by altering the filler's surface charge and dissolving some of the precipitate. This targeted cleaning method penetrates deep into the filler, more thoroughly removing adsorbed impurities. Compared to mixed rinsing, it avoids issues like inadequate or over-cleaning, ensuring optimal cleaning of each filler layer and maximizing the recovery of the filler's adsorption properties.

[0022] 7. During the step-by-step flushing process, the flow of cleaning fluid is controlled by on-off valves, and residual solutions are flushed with nitrogen between each cleaning step. For example, after cleaning the boron adsorbent packing, nitrogen is used to flush away residual acidic solution to prevent it from entering the phosphorus adsorbent packing layer and affecting the cleaning effect of phosphorus impurities and packing performance. Similarly, residual non-alkaline cleaning agents are flushed after cleaning the phosphorus adsorbent packing to prevent them from damaging the chelate resin packing. This effectively prevents cross-contamination between cleaning steps, ensures the independence and effectiveness of cleaning each packing layer, and thus improves overall cleaning quality.

[0023] 8. Sequential rinsing allows boron and phosphorus impurities to be eluted in their respective cleaning steps, effectively increasing the concentrations of these impurities in the cleaning solution. For example, an acidic cleaning solution specifically used to clean boron adsorbent packing will result in a relatively high concentration of boron impurities in the collected acidic cleaning solution. A non-alkaline cleaning solution used to clean phosphorus adsorbent packing will also result in a more concentrated concentration of phosphorus impurities in the collected solution. This highly concentrated impurity solution is more conducive to subsequent separation and purification using methods such as precipitation, crystallization, and ion exchange, reducing the processing cost and difficulty of the recovery process and improving the recovery rate and purity of boron and phosphorus. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the accompanying drawings and examples: Figure 1 It is the process diagram of the present invention; Figure 2 This is a schematic diagram of the structure of the boron and phosphorus removal adsorption column of the present invention; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 for Figure 2 Enlarged view of point B; Figure 5 This is a schematic structural diagram of the cleaning component of the present invention.

[0025] In the figure: column 101, central grid tube 102, grid partition 103, boron adsorption filler 104, phosphorus adsorption filler 105, chelate resin filler 106, cleaning component 107, cleaning main pipeline 107.1, cleaning nozzle 107.2, soft partition plate 107.3, switch valve 107.4, concave positioning groove 107.5, positioning cone 108, cold hydrogenation treatment device 802; cold hydrogenation distillation tower 803. DETAILED DESCRIPTION

[0026] Example 1: The preferred solution is Figures 1 to 5 As shown, a continuous production and preparation system for electronic-grade silane gas includes a raw material supply system, a reaction synthesis system, a separation and purification system, an adsorption purification system, an exhaust gas treatment system, and a filling system.

[0027] 1. The raw material supply system includes raw material tanks for storing hydrogen, silicon powder, silicon tetrachloride, trichlorosilane and other raw materials. The raw material tanks are connected to subsequent equipment through pipelines and delivery pumps to ensure a stable and continuous supply of raw materials.

[0028] 2. Reaction Synthesis System: This system includes hydrogenation and disproportionation reactions. Trichlorosilane, produced by the hydrogenation reaction (using a cold hydrotreating unit), serves as the raw material for silane production. This raw material is then processed through a two-stage disproportionation reactor to produce silane. The disproportionation reaction is carried out in a high-pressure reactor using a high-surface-area, stable, and surface-active solid catalyst to enhance reaction rate and yield. The reaction temperature is controlled between 30-100°C and the pressure between 1.5-3.5 MPa.

[0029] Silicon tetrachloride undergoes hydrogenation to generate trichlorosilane, which then undergoes disproportionation to generate dichlorosilane, which then undergoes disproportionation again to generate silane. The reaction equation is: SiCl4+ H2+ Si→SiHCl3; SiHCl3→SiH2Cl2+ SiCl4; SiH2Cl2→SiHCl3+ SiH4; The fixed-bed reactor uses a special inlet distributor design to improve material distribution uniformity, ensuring residence time and conversion rate. The silicon tetrachloride generated by the disproportionation reaction can be returned to the cold hydrogenation system to prepare the raw material trichlorosilane, forming a closed loop for the entire production process without by-products. The fixed bed is operated in a one-on-one standby mode, and the catalyst can be switched out and replaced at any time if it fails, ensuring strong operational continuity.

[0030] 3. Separation and Purification System: This system consists of multiple distillation towers (including towers 1, 2, 3, and 4) to separate and purify the silane generated from the reaction from other impurities and byproducts. An automated control system is implemented to optimize the silane distillation process. First, the system is equipped with remote thermometers and pressure gauges, along with interlocking control valves, to precisely control parameters such as temperature, pressure, and reflux ratio. Real-time data collection and feedback adjustments ensure that each operating parameter remains within the optimal range.

[0031] The trichlorosilane produced by the cold hydrogenation reaction unit is purified through cold hydrogenation distillation, with distillation in towers one and two. Tower one primarily separates dichlorosilane from the trichlorosilane. The light components extracted from its distillate and the material in the unit's tail gas system are primarily a mixture of dichlorosilane and trichlorosilane. The distillate from tower two is purified trichlorosilane. The purified trichlorosilane is passed through a boron and phosphorus removal adsorption column in the silane production framework to further remove boron and phosphorus impurities. It is then reacted and purified in a de-disproportionation distillation unit to produce high-purity silane gas.

[0032] 1) The fraction extracted from the first disproportionation distillation tower, the tail gas from the cold hydrodistillation unit and other light components, and the silicon tetrachloride extracted from the bottom of the first disproportionation distillation tower are mixed and reacted in an anti-disproportionation reactor. Excess silicon tetrachloride reacts with dichlorodihydrosilane to produce trichlorosilane and unreacted silicon tetrachloride, which are then sent to the cold hydrodistillation unit for separation. This method can effectively reduce the content of dichlorodihydrosilane in the cold hydrodistillation system, reduce the amount of tail gas, and save tail gas treatment costs.

[0033] 2) Using a differential pressure thermal coupling process, the pressure difference between towers 1 and 2 is 0.2-0.5 MPa. The latent heat of the steam at the top of tower 1 is used to heat the reboiler at the bottom of tower 2. The steam from the top of tower 2 is pressurized and heated by a compressor before entering the bottom of tower 1, creating a thermal coupling between the two towers and effectively reducing the energy required for material separation.

[0034] 3) Waste heat recovery: The high-temperature condensate after steam condensation is collected in the steam condensate tank. Before the raw materials enter the production system, they are preheated by the condensate through the heat exchanger, thereby reducing the energy consumption required for subsequent heating. After the heat exchange, the condensate temperature is lowered and can be returned to the steam condensate tank for recycling.

[0035] This system can significantly reduce the energy consumption required for material separation, improving the economic efficiency and stability of production. Through the separation effect of the distillation tower, the purity of silane can be increased to above 6N.

[0036] IV. Adsorption Purification System: This system includes an adsorption unit that utilizes chelate resin's deep adsorption technology to remove trace impurities from silane gas. Chelating resins, through their branched functional groups, coordinate with metal ions such as boron and phosphorus, forming a stable structure similar to a small molecule chelate, enabling targeted adsorption of boron and phosphorus impurities.

[0037] In the present invention, first chelate resin is carried out pre-treatment to ensure the activity of its functional group. Then, silane gas is passed through an adsorption column in which chelate resin is housed. In the adsorption process, impurities such as boron and phosphorus are directed to be adsorbed on the chelate resin, and silane gas is further purified to remove trace impurities therein, thereby ensuring that the purity of silane gas reaches the electronic grade requirement.

[0038] The raw material trichlorosilane removes boron and phosphorus through ion exchange and complexation with a resin adsorbent. The branched functional groups on the resin react with metal ions such as boron and phosphorus to form a stable structure similar to a small molecule chelate. The functional groups have a strong complexing effect on boron and phosphorus. These functional groups form stable complexes with borate ions, and their anion exchange groups capture the resulting complex anions, thereby achieving selective adsorption of boron. Silane uses a modified molecular sieve adsorbent, which has a higher selective adsorption capacity for certain substances. After the high-efficiency adsorbent was introduced into the process unit, the process parameters were fully optimized, with particular attention to the distillation column operating conditions, such as temperature, pressure, reflux ratio, and steam usage, which were carefully adjusted.

[0039] 5. Tail Gas Treatment System: This system treats tail gas generated during the reaction to meet environmental protection requirements. No waste liquid is discharged from the system; chlorosilane and silane waste gas is sent to the leaching system, while silane accident and emergency waste gas is incinerated in a flare.

[0040] 6. Filling system: Fill electronic grade silane with purity of 6N (≥99.9999%) and above into torpedo trucks or Y bottles for external sale.

[0041] The working principle of this system is: The crude trichlorosilane produced by the cold hydrotreating unit is purified in a cold hydrodistillation column and then fed to the boron and phosphorus removal adsorption column in the silane production framework. After further removal of boron and phosphorus impurities, the trichlorosilane is fed to the primary disproportionator for a disproportionation reaction. The product after the primary disproportionation reaction enters the first tower. Tower one removes the STC (silicon tetrachloride) produced in the primary disproportionation reaction and extracts it from the bottom of the tower for feeding to the cold hydrodistillation tower. The STC-free chlorosilane material is extracted from the top of the tower and fed to the second tower. Tower two separates the extracted chlorosilane material. Trichlorosilane (TCS) is extracted from the bottom of tower two and fed to the primary disproportionator for further disproportionation. The chlorosilane material extracted from the top of the tower is fed to the secondary disproportionator for further disproportionation. The product after the secondary disproportionation reaction enters the third tower, which separates silane and chlorosilane. Unreacted chlorosilane is extracted from the bottom of the tower and returned to tower two for further separation. The crude gaseous silane extracted from the top of the tower enters the silane adsorption column for adsorption and impurity removal. The impurity-free material enters the fourth tower, where light and heavy silane impurities are intermittently discharged from the top and bottom of the silane refining tower. The gaseous silane product is produced from the side sampling, condensed, and sent to the silane tank farm. The liquid silane vaporized in the tank farm is then sent to the silane filling system, where it is filled into torpedo trucks or Y-bottles for sale.

[0042] Example 2: In addition, the present invention provides a specific structure of a boron and phosphorus removal adsorption column, which includes a column 101, a central grid tube 102 is provided in the middle of the column 101, and a plurality of grid partitions 103 are provided on the inner wall of the column 101 from bottom to top. The plurality of grid partitions 103 divide the column 101 into three packing layers, and the three packing layers are respectively a boron adsorption filler 104, a phosphorus adsorption filler 105 and a chelate resin filler 106 from bottom to top; Boron adsorption fillers are made from materials that do not react with trichlorosilane, such as specific molecular sieves. These materials have a porous structure and suitable surface chemistry, effectively adsorbing boron impurities. Their chemical stability also prevents them from reacting with trichlorosilane. Acid cleaning desorbs components that form complexes with borate ions from the filler surface, effectively cleaning the boron adsorption filler.

[0043] Phosphorus adsorption filler 105: Iron-aluminum-based adsorbents, such as activated alumina and ferric oxide, have abundant hydroxyl groups on their surfaces. Under acidic conditions, these hydroxyl groups become protonated, becoming positively charged. This electrostatic attraction then interacts with negatively charged phosphate ions, resulting in phosphorus adsorption. Furthermore, iron and aluminum ions can form insoluble phosphate precipitates with phosphate, further enhancing phosphorus adsorption.

[0044] The chelate resin filler 106 undergoes coordination reaction with metal ions such as boron and phosphorus through branched functional groups to form a stable structure similar to a small molecule chelate, thereby achieving directional adsorption of boron and phosphorus impurities.

[0045] In this embodiment, three filler layers are provided for the purpose of first adsorbing boron, then adsorbing phosphorus, and finally adsorbing the residual boron and phosphorus.

[0046] A cleaning assembly 107 is provided in the central grid cylinder 102 , and the cleaning assembly 107 is used to clean the three packing layers.

[0047] The cleaning assembly 107 includes a cleaning main pipe 107.1, on which a plurality of cleaning nozzles 107.2 are provided; At least two soft partition plates 107.3 are provided on the cleaning main pipe 107.1. The soft partition plates 107.3 are located at the junction of the two packing layers. The cleaning main pipeline 107.1 is provided with a plurality of switch valves 107.4, which are located at the junction of the two packing layers; A concave positioning groove 107.5 is provided at the bottom of the cleaning main pipe 107.1. The concave positioning groove 107.5 is adapted to a positioning cone 108. The positioning cone 108 has a through hole and is used to form a passage with the concave positioning groove 107.5. The positioning cone 108 is connected to the cleaning liquid inlet pipe. A cleaning liquid branch pipe and a purge branch pipe are provided on the cleaning liquid inlet pipeline.

[0048] The cleaning component 107 in this embodiment can clean the three packing layers separately. The cleaning process is as follows: (1) First, an acidic solution is passed through the boron adsorption filler 104 to clean it. The boron adsorption filler is selected from a material that does not react with trichlorosilane, such as a specific molecular sieve material. This type of material has a porous structure and suitable surface chemical properties, can effectively adsorb boron impurities, and has stable chemical properties and does not react with trichlorosilane. Through acid cleaning, the components that form complexes with borate ions can be desorbed from the filler surface, thereby achieving the purpose of cleaning the boron adsorption filler.

[0049] During this cleaning process, the on-off valve 107 . 4 between the boron adsorption filler 104 and the phosphorus adsorption filler 105 is closed.

[0050] (2) Then, nitrogen gas is introduced to flush away the remaining acidic solution.

[0051] (3) Then, a non-alkaline cleaning agent is introduced to clean the phosphorus adsorption filler 105. The phosphorus adsorption filler is an iron-aluminum-based adsorbent, such as activated alumina, ferric oxide, etc. Under acidic conditions, they adsorb phosphorus by electrostatic attraction and forming insoluble phosphate precipitates. The introduction of a non-alkaline cleaning agent such as a specific chelating agent or a neutral buffer solution can change the charge properties of the filler surface, causing the phosphate ions to desorb from the filler surface. At the same time, the non-alkaline cleaning agent can also dissolve some of the iron and aluminum ions that form a precipitate with the phosphate, thereby releasing phosphorus. For example, a specific chelating agent can form a stable complex with iron ions, causing the iron phosphate precipitate to dissolve and achieve phosphorus elution.

[0052] During the cleaning process, the switch valve 107 . 4 between the chelate resin filler 106 and the phosphorus adsorption filler 105 is closed, and the switch valve 107 . 4 between the boron adsorption filler 104 and the phosphorus adsorption filler 105 is opened.

[0053] (4) Then, nitrogen is introduced to flush away the remaining non-alkaline cleaning agent; (5) Finally, all the switch valves 107.4 are opened to flush the boron adsorption filler 104, the phosphorus adsorption filler 105, and the chelating resin filler 106 together.

[0054] Example 3: A production process for a continuous production and preparation system for electronic-grade silane gas, comprising the following methods: S1. Raw material supply: Raw material tanks store hydrogen, silicon powder, silicon tetrachloride, trichlorosilane, and other raw materials, which are stably and continuously transported to the cold hydrotreating unit via pipelines and pumps. S2. Cold hydrogenation and distillation: The cold hydrogenation unit hydrogenates the raw material to produce crude trichlorosilane, which enters the cold hydrogenation distillation tower for distillation and purification. S3. Boron and phosphorus impurity removal: After being purified by the cold hydrogenation distillation column, trichlorosilane enters the boron and phosphorus removal adsorption column and passes through the boron adsorption packing, phosphorus adsorption packing and chelating resin packing set from bottom to top to remove boron, phosphorus impurities and residual trace boron and phosphorus impurities respectively; S4. Disproportionation reaction: After the removal of boron and phosphorus impurities, trichlorosilane is sent to a primary disproportionator for disproportionation reaction. The material after the primary disproportionation reaction enters the first tower; the chlorosilane material without silicon tetrachloride is produced from the top of the first tower and enters the second tower; the trichlorosilane produced from the kettle of the second tower is returned to the primary disproportionator for further reaction, and the chlorosilane material produced from the top of the tower is sent to the secondary disproportionator for further reaction; S5. Multi-stage distillation separation: S5.1 The material after the primary disproportionation reaction enters the first tower, which removes the silicon tetrachloride produced after the reaction. The silicon tetrachloride produced from the bottom of the tower is sent to the cold hydrodistillation tower, and the material produced from the top of the tower enters the second tower; S5.2 The second tower separates the chlorosilane material. The trichlorosilane produced from the bottom of the tower is returned to the first disproportionator, and the material produced from the top of the tower enters the second disproportionator. S5.3 The material after the secondary disproportionation reaction enters the third tower, which separates silane and chlorosilane. The unreacted chlorosilane is withdrawn from the bottom of the tower and returned to the second tower. The crude gaseous silane withdrawn from the top of the tower enters the silane adsorption column. S5.4 After the crude silane is removed from the silane adsorption column, it enters the four-column tower. The four-column tower intermittently discharges silane light and heavy impurities from the top and bottom of the tower. The gaseous silane product produced by the side sampling is condensed and sent to the silane tank area; S6. Tail Gas Treatment: Chlorosilane and silane waste gases generated during the reaction are sent to a leaching system for treatment. Silane waste gases from accidents and emergencies are sent to a flare for incineration, ensuring no waste liquid is discharged from the system and meeting environmental protection requirements. S7. Product Filling: Liquid silane in the silane tank area is vaporized and transported via pipeline to the silane filling system. Electronic-grade silane with a purity of 6N (≥99.9999%) or higher is filled into torpedo trucks or Y-bottles for external sale. S8. Cleaning the adsorption column: When the boron and phosphorus removal adsorption column filler is saturated, clean it according to the following steps: S8.1 Close the on-off valve between the boron adsorption packing and the phosphorus adsorption packing, and pass an acidic solution to clean the boron adsorption packing to desorb boron from the packing surface; S8.2 Introduce nitrogen to flush away the residual acid solution; S8.3 Close the on-off valve between the chelating resin packing and the phosphorus adsorption packing, open the on-off valve between the boron adsorption packing and the phosphorus adsorption packing, and introduce a non-alkaline cleaning agent (such as a specific complexing agent or a neutral buffer solution) to desorb phosphorus impurities by changing the surface charge properties of the packing or dissolving some of the precipitate; S8.4 Introduce nitrogen to flush away any residual non-alkaline cleaning agent; S8.5 Open all the switch valves and flush the three packing layers together to restore the adsorption performance of the packing.

[0055] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. In other words, equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A continuous production and preparation system for electronic grade silane gas, characterized by: It includes a cold hydrotreating device, the inlet of the cold hydrotreating device is connected to the raw material supply system, the outlet of the cold hydrotreating device is connected to the cold hydrodistillation tower through a pipeline, the cold hydrodistillation tower is connected to the boron and phosphorus removal adsorption column, the first-stage disproportionator, the first tower, the second tower, the second-stage disproportionator, the third tower and the fourth tower in sequence through pipelines, and the electronic grade silane in the fourth tower is used to be transported to the silane tank area; One tower is used to remove silicon tetrachloride produced after the disproportionation reaction in the first-stage disproportionator; The second tower is used to separate the extracted chlorosilane materials; Three towers are used to separate silane and chlorosilane; The four towers are used to discharge light impurities and heavy impurities, and transport gaseous electronic grade silane into the silane tank area.

2. The electronic-grade silane gas continuous production and preparation system according to claim 1, characterized in that: A silicon tetrachloride discharge pipe is provided at the bottom of the first tower, which is used to transport silicon tetrachloride to the anti-disproportionation tower of the cold hydrogenation distillation tower to generate trichlorosilane. Trichlorosilane and part of the unreacted silicon tetrachloride are then sent to the crude distillation tower in the cold hydrogenation treatment device for separation and silicon tetrachloride reuse. Trichlorosilane enters the cold hydrogenation distillation tower for further purification.

3. The electronic-grade silane gas continuous production and preparation system according to claim 1, characterized in that: The trichlorosilane in the kettle of the second tower is connected to the kettle of the first disproportionator through a pipeline.

4. The electronic-grade silane gas continuous production and preparation system according to claim 1, characterized in that: The kettle of the third tower is connected to the second tower through a pipeline and is used to output unreacted chlorosilane to the second tower.

5. The electronic-grade silane gas continuous production and preparation system according to claim 4, characterized in that: The crude silane in the gas phase extracted from the top of the three towers enters the silane adsorption column for adsorption and impurity removal and is then output to the four towers; the accident exhaust gas extracted from the top of the three towers is used to be output to the flare.

6. The electronic-grade silane gas continuous production and preparation system according to claim 1, characterized in that: The top and bottom of the four towers intermittently discharge light and heavy silane impurities respectively, and the gaseous silane products taken out from the sides of the four towers are sent to the silane tank area after condensation.

7. The electronic-grade silane gas continuous production and preparation system according to claim 1, characterized in that: The liquid silane in the silane tank area is vaporized and sent to the silane filling system through a pipeline; the accident exhaust gas from the silane filling system and the silane tank area is output to the flare.

8. The electronic-grade silane gas continuous production and preparation system according to claim 1, characterized in that: The boron and phosphorus removal adsorption column includes a column body, a central grid cylinder is provided in the middle of the column body, and a plurality of grid partitions are provided on the inner wall of the column body from bottom to top. The plurality of grid partitions divide the column body into three packing layers, and the three packing layers are respectively boron adsorption filler, phosphorus adsorption filler and chelate resin filler from bottom to top; A cleaning component is provided in the central grid cylinder, and the cleaning component is used to clean the three filler layers.

9. The electronic-grade silane gas continuous production and preparation system according to claim 8, characterized in that: The cleaning assembly includes a cleaning main pipe, on which a number of cleaning nozzles are provided; At least two soft partition plates are provided on the cleaning main pipe, and the soft partition plates are located at the junction of the two packing layers; The cleaning main pipeline is equipped with multiple switch valves, which are located at the junction of two packing layers; A concave positioning groove is provided at the bottom of the cleaning main pipeline, the concave positioning groove is adapted to the positioning cone, the positioning cone is provided with a through hole and is used to form a passage with the concave positioning groove; the positioning cone is connected to the cleaning liquid inlet pipeline; A cleaning liquid branch pipe and a purge branch pipe are provided on the cleaning liquid inlet pipeline.

10. The production process of a continuous production system for electronic-grade silane gas according to any one of claims 1 to 9, characterized in that This includes the following methods: S1. Raw material supply: Raw material tanks store hydrogen, silicon powder, silicon tetrachloride, and trichlorosilane. Pipelines and pumps deliver these raw materials stably and continuously to the cold hydrotreating unit. S2. Cold hydrogenation and distillation: The cold hydrogenation unit hydrogenates the raw material to produce crude trichlorosilane, which enters the cold hydrogenation distillation tower for distillation and purification. S3. Boron and phosphorus impurity removal: After being purified by the cold hydrogenation distillation column, trichlorosilane enters the boron and phosphorus removal adsorption column and passes through the boron adsorption packing, phosphorus adsorption packing and chelating resin packing set from bottom to top to remove boron, phosphorus impurities and residual trace boron and phosphorus impurities respectively; S4. Disproportionation reaction: After the removal of boron and phosphorus impurities, trichlorosilane is sent to a primary disproportionator for disproportionation reaction. The material after the primary disproportionation reaction enters the first tower; the chlorosilane material without silicon tetrachloride is produced from the top of the first tower and enters the second tower; the trichlorosilane produced from the kettle of the second tower is returned to the primary disproportionator for further reaction, and the chlorosilane material produced from the top of the tower is sent to the secondary disproportionator for further reaction; S5. Multi-stage distillation separation: S5.1 The material after the primary disproportionation reaction enters the first tower, which removes the silicon tetrachloride produced after the reaction. The silicon tetrachloride produced from the bottom of the tower is sent to the anti-disproportionation tower of the cold hydrodistillation tower to produce trichlorosilane. The trichlorosilane and some unreacted silicon tetrachloride are then sent to the crude distillation tower in the cold hydrotreating unit for separation. The silicon tetrachloride and trichlorosilane enter the cold hydrodistillation tower for further purification. The material produced from the tower top enters the second tower; S5.2 The second tower separates the chlorosilane material. The trichlorosilane produced from the bottom of the tower is returned to the first disproportionator, and the material produced from the top of the tower enters the second disproportionator. S5.3 The material after the secondary disproportionation reaction enters the third tower, which separates silane and chlorosilane. The unreacted chlorosilane is withdrawn from the bottom of the tower and returned to the second tower. The crude gaseous silane withdrawn from the top of the tower enters the silane adsorption column. S5.4 After the crude silane is removed from the silane adsorption column, it enters the four-column tower. The four-column tower intermittently discharges silane light and heavy impurities from the top and bottom of the tower. The gaseous silane product produced by the side sampling is condensed and sent to the silane tank area; S6. Tail gas treatment: Chlorosilane and silane waste gases generated during the reaction are sent to the leaching system for treatment; waste gases from silane accidents and emergencies are sent to a flare for incineration; S7. Product filling: Liquid silane in the silane tank area is vaporized and transported via pipelines to the silane filling system. S8. Cleaning the adsorption column: When the boron and phosphorus removal adsorption column filler is saturated, clean it according to the following steps: S8.1 Close the on-off valve between the boron adsorption packing and the phosphorus adsorption packing, and pass an acidic solution to clean the boron adsorption packing to desorb boron from the packing surface; S8.2 Introduce nitrogen to flush away the residual acid solution; S8.3 Close the on-off valve between the chelating resin packing and the phosphorus adsorption packing, open the on-off valve between the boron adsorption packing and the phosphorus adsorption packing, and introduce a non-alkaline cleaning agent (such as a specific complexing agent or a neutral buffer solution) to desorb phosphorus impurities by changing the surface charge properties of the packing or dissolving some of the precipitates. S8.4 Introduce nitrogen to flush away any residual non-alkaline cleaning agent; S8.5 Open all the switch valves and flush the three packing layers together to restore the adsorption performance of the packing.

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