Cold hydrogenation production process and device

Abstract

The embodiment of the invention provides a cold hydrogenation production process and device, and the process comprises the steps: introducing a mixed material of hydrogen, silicon tetrachloride and silicon powder into a fluidized bed reactor, carrying out hydrogenation reaction, generating chlorosilane mixed gas, introducing the chlorosilane mixed gas into a coiled tube heat exchanger, carrying out first-stage cooling, and carrying out second-stage cooling; removing silicon powder from the chlorosilane mixed gas output from the coiled tube heat exchanger through a filter unit, introducing the chlorosilane mixed gas output from the filter unit into a heat exchanger for secondary cooling, quenching and washing the chlorosilane mixed gas output from the heat exchanger, and condensing and separating the quenched and washed chlorosilane mixed gas to obtain the chlorosilane gas. The chlorosilane and the hydrogen are obtained. By adopting the coiled tube heat exchanger and immediately filtering after cooling, the problems that a traditional tubular heat exchanger is easy to block and low in heat transfer efficiency are effectively solved, the heat energy recovery efficiency is improved, the system energy consumption is reduced, and the equipment operation cycle is prolonged.

Description

Technical Field

[0001] This application relates to the field of polysilicon production technology, and in particular to a cold hydrogenation production process and apparatus. Background Technology

[0002] In the cold hydrogenation process, the high-temperature mixed gas at the reactor outlet needs to undergo heat exchange, separation, and washing to recover useful components and remove impurities. The heat recovery efficiency and equipment operation stability in this stage directly affect the energy consumption and economy of the entire process.

[0003] In the relevant technical solution, the high-temperature reaction gas is first cooled by a two-stage shell-and-tube heat exchanger, then most of the silicon powder is removed by a cyclone separator and a silicon powder filter, and then it enters a quench tower for spraying and washing. Finally, chlorosilane and hydrogen are recovered through a multi-stage condensation system.

[0004] However, the heat exchange efficiency of the shell-and-tube heat exchanger using the relevant technology is insufficient, and a large amount of high-temperature reaction heat cannot be effectively recovered and utilized. This increases the reliance of subsequent processes on external heat sources such as electric heaters, resulting in higher overall power consumption. At the same time, the fine silicon powder entrained in the reaction gas is very easy to deposit on the tube walls of the shell-and-tube heat exchanger, causing scaling, blockage, and accelerated wear of the equipment. Frequent shutdowns for cleaning are required, which seriously affects the continuity and stability of production. Summary of the Invention

[0005] This application provides a cold hydrogenation production process and apparatus to improve heat exchange efficiency, reduce energy consumption, and solve equipment wear and blockage problems, so as to meet the high efficiency, energy saving and stability requirements of industrial production.

[0006] In a first aspect, embodiments of this application provide a cold hydrogenation production process, including:

[0007] A mixture of hydrogen, silicon tetrachloride, and silicon powder is fed into a fluidized bed reactor for hydrogenation to produce a chlorosilane mixture.

[0008] The chlorosilane mixed gas is passed into a coiled tube heat exchanger for primary cooling.

[0009] The chlorosilane mixed gas output from the coiled heat exchanger is filtered to remove silicon powder.

[0010] The chlorosilane mixed gas output from the filter unit is passed into a heat exchanger for secondary cooling;

[0011] The chlorosilane mixture gas output from the heat exchanger is subjected to rapid cooling and washing;

[0012] The chlorosilane mixture gas after rapid cooling and washing is condensed and separated to obtain chlorosilane and hydrogen.

[0013] In one possible implementation, the removal of silicon powder from the chlorosilane mixture gas output from the coiled tube heat exchanger by passing it through a filtration unit includes:

[0014] The filtration unit includes a cyclone separator and a silica powder filter connected in sequence;

[0015] The chlorosilane mixed gas output from the coiled heat exchanger is passed into the cyclone separator for gas-solid separation to remove silicon powder.

[0016] The chlorosilane mixture gas after gas-solid separation is passed into the silicon powder filter to remove silicon powder.

[0017] In one possible implementation, the filtration unit includes a first silicon powder receiver and a second silicon powder receiver, the first silicon powder receiver being connected to the cyclone separator and the second silicon powder receiver being connected to the silicon powder filter;

[0018] The silicon powder removed by the cyclone separator and the silicon powder filter enters the first silicon powder receiver and the second silicon powder receiver.

[0019] In one possible implementation, the rapid cooling and scrubbing of the chlorosilane mixture gas output from the heat exchanger includes:

[0020] The chlorosilane mixed gas output from the heat exchanger is passed into a quench tower for quenching and washing.

[0021] The chlorosilane liquid condensed by the cold hydrogenation process is sprayed.

[0022] The spray medium is evenly sprayed into the quench tower through a multi-layer distributor to achieve cooling and impurity removal.

[0023] In one possible implementation, the impurities are conveyed to a filter for filtration and then conveyed to a slurry system.

[0024] In one possible implementation, the condensation and separation of the chlorosilane mixture gas after rapid cooling and washing includes:

[0025] The chlorosilane mixed gas output from the top outlet of the quench tower undergoes multi-stage condensation and separation by sequentially passing through a circulating hydrogen heat exchanger, a silicon tetrachloride heat exchanger, an air cooler, a circulating water heat exchanger, a chilled water heat exchanger, an intermediate heat exchanger, and a terminal condenser.

[0026] The intermediate heat exchanger and the terminal condenser output hydrogen gas.

[0027] The condensate that has undergone the multi-stage condensation and separation process is discharged into the hydrogenated liquid storage tank.

[0028] In one possible implementation, hydrogen discharged from the intermediate heat exchanger and the terminal condenser is delivered to a circulating hydrogen buffer tank.

[0029] The circulating hydrogen buffer tank is connected in sequence to the circulating hydrogen compressor and the circulating hydrogen heat exchanger.

[0030] In one possible implementation, the hydrogenation reaction, which involves feeding a mixture of hydrogen, silicon tetrachloride, and silicon powder into a fluidized bed reactor, includes:

[0031] The mixture is sequentially passed through a quench tower top heat exchanger, a silicon tetrachloride vaporizer, a reaction feed heater, and an electric heater for multi-stage heating and vaporization.

[0032] In one possible implementation, external silicon powder is transported via a silicon powder collector and a silicon powder feeder to a cold hydrogenation reactor to undergo a hydrogenation reaction with multi-stage heated hydrogen and silicon tetrachloride.

[0033] Secondly, embodiments of this application provide a cold hydrogenation production apparatus, which employs the aforementioned cold hydrogenation production process to perform cold hydrogenation production, including:

[0034] A coiled tube heat exchanger, wherein the flow channel of the coiled tube heat exchanger has a spiral or corrugated structure, is used for staged heating of a mixture of hydrogen and silicon tetrachloride.

[0035] A fluidized bed reactor, connected to the output end of the coiled tube heat exchanger, is used for hydrogenation reaction under the action of a catalyst;

[0036] The filtration structure includes a cyclone separator and a silicon powder filter connected in sequence, for removing silicon powder from the mixed gas;

[0037] A heat exchanger, connected to the output end of the filter structure, is used to cool the filtered mixed gas.

[0038] A quench tower, connected to the output of the heat exchanger, is used to quench and wash the mixed gas.

[0039] Compared with the prior art, the beneficial effects of this application are at least as follows:

[0040] In this application, the chlorosilane mixture generated in the reaction is first passed through a coiled tube heat exchanger for primary cooling. Compared to the use of shell-and-tube heat exchangers with lower heat transfer coefficients in related technologies, the coiled tube heat exchanger, with its unique spiral or corrugated flow channel design, significantly enhances the turbulence of the gas flow, thereby greatly improving heat transfer efficiency. This allows the heat from the reacting gas to be removed more quickly and completely, laying the foundation for efficient cooling.

[0041] Following the primary cooling step, the gas is passed through a filtration unit containing a cyclone separator and a silicon powder filter to remove silicon powder. This dust removal step, placed after the coiled tube heat exchanger, ensures that the gas entering the heat exchanger is high-temperature, untreated gas. The high temperature makes it difficult for silicon powder particles to adhere and deposit within the heat exchanger channels, thus fundamentally avoiding the risk of scaling and clogging inside the heat exchanger. This optimized process sequence effectively protects the coiled tube heat exchanger, significantly extending its continuous operating cycle and maintenance intervals. Attached Figure Description

[0042] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0043] Figure 1 This is a flowchart illustrating the process of this application;

[0044] Figure 2 This is a schematic diagram of the cold hydrogenation process provided in this application.

[0045] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the absence of conflict, the following embodiments and features can be combined with each other.

[0047] Cold hydrogenation is a core step in polysilicon production, primarily used to hydrogenate silicon tetrachloride (SiCl₂). ),hydrogen( ) and silicon powder reacts under high temperature and high pressure conditions to produce trichlorosilane ( This process produces chlorosilane products such as silicon tetrachloride (SiCl2). It is widely used in the photovoltaic industry and semiconductor material manufacturing, and is currently the mainstream technology for large-scale production of high-purity polycrystalline silicon. In the cold hydrogenation reaction, a mixture of hydrogen and silicon tetrachloride is reacted with silicon powder in a fluidized bed reactor at 565-590℃ and 2.5-2.9MPa to generate the target product. The gas after the reaction typically contains high-boiling-point chlorosilanes, metal chlorides, and trace amounts of silicon powder, which need to be separated and purified through rapid cooling, washing, and condensation. Because the reaction involves a high-temperature and high-pressure environment, and the reaction gas contains easily clogging solid particles and corrosive substances, extremely high requirements are placed on thermal efficiency, equipment wear resistance, and process stability.

[0048] In existing processes, shell-and-tube heat exchangers suffer from low heat transfer efficiency and are prone to scaling and clogging, resulting in high energy consumption for electric heaters. Frequent equipment maintenance and shutdowns also severely impact production continuity. Furthermore, the silicon powder particles carried by the high-temperature gas from the reactor outlet directly entering the heat exchanger accelerate wear on the heat exchanger pipes and cause localized scaling, further reducing heat recovery efficiency.

[0049] Existing cold hydrogenation processes typically include units such as hydrogen compression and heating, silicon tetrachloride vaporization, hydrogenation reaction, filtration and dust removal, washing and impurity removal, and multi-stage condensation. Specifically:

[0050] Hydrogen compression heating unit: The electrolytic hydrogen and circulating hydrogen are pressurized to the pressure required for the reaction (2.5-2.9MPa) by the compressor, and then heated to the reaction temperature (565-590℃) by the circulating hydrogen heater and hydrogen heater.

[0051] Silicon tetrachloride vaporization unit: Liquid silicon tetrachloride is mixed with heated hydrogen gas and then passed through the quench tower top heat exchanger, silicon tetrachloride vaporizer, reaction feed heater and other equipment in stages to be heated to the reaction conditions.

[0052] Hydrogenation reaction unit: The mixed gas and silicon powder undergo a hydrogenation reaction in a fluidized bed reactor to produce a mixture of chlorosilanes.

[0053] Filtration and dust removal unit: The reaction gas passes through a cyclone separator and a silicon powder filter in sequence to initially remove the silicon powder particles it carries.

[0054] Washing and impurity removal unit: The gas enters the quench tower and is washed by spray cooling to separate metal chlorides, high boiling points and residual silicon powder. The slurry in the tower bottom is periodically discharged to the slurry treatment system.

[0055] Multi-stage condensation unit: The washed gas is cooled by a multi-stage heat exchanger (such as a quench tower top heat exchanger, a circulating hydrogen heat exchanger, an air cooler, etc.), and chlorosilane liquid is separated by condensation. The remaining hydrogen is recycled.

[0056] In existing technologies, shell-and-tube heat exchangers are widely used in the recovery of heat energy from reaction gases. However, this type of heat exchanger has the following problems:

[0057] Low heat exchange efficiency: The limited heat transfer area and complex flow channels of the tube-and-shell structure result in insufficient heat recovery rate, requiring high-power electric heaters to supplement heat, which significantly increases energy consumption.

[0058] Easy to clog and scale: Silica particles carried in the reaction gas deposit in the heat exchanger pipes, forming local blockages and scale, requiring frequent shutdowns for cleaning, which affects the continuity of production.

[0059] Thermal stress concentration: High-temperature gas directly impacts the heat exchanger pipeline, which can easily cause local overheating or uneven cooling, leading to fatigue damage to the equipment.

[0060] Furthermore, the layout sequence of the filtration and dust removal unit and the heat exchanger in the existing process is unreasonable. Silica particles may still enter subsequent heat exchangers after filtration, further exacerbating equipment wear. These defects collectively result in significant bottlenecks in energy efficiency, equipment lifespan, and operational stability of the existing cold hydrogenation process.

[0061] To overcome the shortcomings of existing technologies, this application proposes a cold hydrogenation production process and apparatus. It replaces the traditional shell-and-tube heat exchanger with a wound-tube heat exchanger and optimizes the sequence of filtration and heat exchange units in the process flow to achieve efficient heat recovery, improved equipment anti-clogging performance, and reduced overall energy consumption in the cold hydrogenation process. The wound-tube heat exchanger significantly improves heat transfer efficiency by increasing the heat exchange area and optimizing the flow channel design. Its structural characteristics also reduce the risk of silicon powder particle deposition on the heat exchange surface. Furthermore, by placing the filtration unit at the heat exchanger inlet, silicon powder particles in the reaction gas can be effectively intercepted, preventing them from entering subsequent heat exchange equipment, thereby extending equipment life and reducing maintenance costs. This application solves the core problems of low thermal energy utilization, frequent equipment clogging, and excessive energy consumption in existing cold hydrogenation processes, providing a highly efficient, stable, and energy-saving process solution for polysilicon production.

[0062] This application pertains to a cold hydrogenation process system in polysilicon production, specifically involving the hydrogenation reaction of hydrogen, silicon tetrachloride, and silicon powder under high temperature and pressure. The process system includes a hydrogen compression and heating unit, a silicon tetrachloride vaporization unit, a fluidized bed reactor, a filtration and dust removal unit, a quenching and washing unit, and a multi-stage condensation and recovery unit. Core equipment includes coiled-tube heat exchangers (E04, E05), cyclone separators, silicon powder filters, quench towers, and multi-stage heat exchangers (such as circulating hydrogen heat exchangers and air coolers). In the reaction gas handling process, coiled-tube heat exchangers replace the traditional shell-and-tube structure, and the filtration and dust removal unit is placed at the heat exchanger inlet, forming an optimized process chain of filtration, heat exchange, washing, and condensation. This technical solution can be widely applied in the photovoltaic industry and semiconductor material manufacturing field, meeting the needs of large-scale production of high-purity polysilicon.

[0063] Based on an in-depth analysis of existing cold hydrogenation processes, this application first focuses on the insufficient heat transfer efficiency and anti-clogging capability of shell-and-tube heat exchangers. By comparing the performance differences of different heat exchanger structures, it was found that the coiled-tube heat exchanger, due to its more compact flow channel design, larger heat transfer area, and better matching of fluid flow direction with the heat transfer surface, can effectively reduce the deposition of silicon powder particles. Secondly, addressing the issue of unreasonable layout sequence between the filtration and dust removal unit and the heat exchanger, this application proposes placing the filtration unit at the heat exchanger inlet to intercept silicon powder particles and reduce the wear risk of subsequent equipment. Furthermore, the application optimizes the staged heating path of the silicon tetrachloride vaporization unit and the reaction feed heater to ensure that the reactant gas reaches optimal temperature conditions before entering the coiled-tube heat exchanger, thereby improving heat recovery efficiency. Finally, by integrating the high-efficiency heat transfer characteristics of the coiled-tube heat exchanger, the pre-positioned layout of the filtration and dust removal unit, and the staged heating process, a cold hydrogenation process system that balances heat optimization, improved equipment anti-clogging performance, and reduced energy consumption is formed.

[0064] The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can have a clearer and more detailed understanding of the present invention.

[0065] See Figure 1 , Figure 2 This application discloses a cold hydrogenation production process, comprising:

[0066] S301, a mixture of hydrogen, silicon tetrachloride and silicon powder is fed into a fluidized bed reactor for hydrogenation reaction to generate a chlorosilane mixed gas;

[0067] S302, the chlorosilane mixed gas is introduced into the coiled tube heat exchanger for primary cooling;

[0068] S303 removes silicon powder from the chlorosilane mixed gas output from the coiled tube heat exchanger through a filter unit;

[0069] S304, the chlorosilane mixed gas output from the filter unit is introduced into the heat exchanger for secondary cooling;

[0070] S305, the chlorosilane mixed gas output from the heat exchanger is rapidly cooled and washed;

[0071] S306, the chlorosilane mixture gas after rapid cooling and washing is condensed and separated to obtain chlorosilane and hydrogen.

[0072] Tube-wound heat exchanger: A heat exchange device with a spiral or corrugated flow channel, which improves heat transfer efficiency by enhancing turbulence. Example: E04 heat exchanger with a corrugated flow channel inner wall structure.

[0073] Filtration unit: A combination of devices used to remove solid particles (such as silica powder) from gases, including cyclone separators and silica powder filters. Example: A filtration system consisting of a cyclone separator and a silica powder filter connected in series.

[0074] Heat exchanger: A device that cools a gas through heat conduction, typically used in conjunction with a condensation separation process. Examples: E05 heat exchanger or quench tower top heat exchanger.

[0075] In this embodiment, S301: A mixture of hydrogen, silicon tetrachloride, and silicon powder is introduced into a fluidized bed reactor for hydrogenation reaction to generate a chlorosilane mixed gas.

[0076] First, hydrogen, silicon tetrachloride, and silicon powder are mixed in a predetermined ratio to form a mixture. Before mixing, the hydrogen needs to be pretreated to remove impurities such as moisture and oxygen, ensuring that the hydrogen purity meets industrial production requirements (preferably ≥99.99%). The silicon tetrachloride raw material also needs to be pretreated to remove mechanical impurities and high-boiling substances to avoid affecting the reaction. Then, the pretreated mixture is fed into a fluidized bed reactor for hydrogenation under high temperature, high pressure, and the action of a catalyst. The reaction conditions are controlled as follows: temperature 565-590℃, pressure 2.5-2.9MPa, and copper chloride is used as the catalyst. Through the catalytic action of the catalyst, hydrogen, silicon tetrachloride, and silicon powder undergo a hydrogenation reaction to generate a chlorosilane mixture containing components such as trichlorosilane, silicon tetrachloride, and dichlorosilane.

[0077] In this embodiment, S302: The chlorosilane mixed gas is introduced into the coiled tube heat exchanger for primary cooling.

[0078] The chlorosilane mixture generated by the hydrogenation reaction has a high temperature (typically above 565℃), and directly introducing it into subsequent processes can easily lead to equipment damage and impurity deposition. Therefore, a primary cooling process is required. This chlorosilane mixture is passed into a coiled tube heat exchanger. The flow channels of the coiled tube heat exchanger employ a spiral or corrugated structure, which significantly enhances gas turbulence and improves the heat transfer coefficient compared to traditional shell-and-tube heat exchangers, achieving highly efficient heat exchange. Through heat exchange between the coiled tube heat exchanger and the heat exchange medium, the temperature of the chlorosilane mixture is reduced to a preset range (preferably to 380-420℃), providing suitable operating conditions for subsequent filtration processes. Simultaneously, utilizing the highly efficient heat exchange characteristics of the coiled tube heat exchanger, some waste heat can be recovered for preheating subsequent materials, improving energy utilization.

[0079] In this embodiment, S303: The chlorosilane mixed gas output from the coiled tube heat exchanger is filtered to remove silicon powder.

[0080] Even after primary cooling, the chlorosilane mixture still carries silicon powder impurities generated during the reaction. Directly introducing this into subsequent heat exchange equipment could easily cause blockages; therefore, a filtration unit is needed to specifically remove the silicon powder. The filtration unit comprises a cyclone separator and a silicon powder filter connected in sequence, forming a staged filtration structure. First, the chlorosilane mixture output from the coiled tube heat exchanger is passed into the cyclone separator, where centrifugal force achieves gas-solid separation, removing coarse silicon powder particles larger than 10 μm. Then, the gas processed by the cyclone separator is passed into the silicon powder filter, where multiple layers of high-precision filter screens (with progressively smaller pore sizes, preferably 20 μm, 10 μm, and 5 μm) further remove fine silicon powder particles smaller than 10 μm, ensuring that the silicon powder content in the outlet gas meets the requirements of subsequent processes.

[0081] To achieve centralized collection and processing of silicon powder, the filtration unit is equipped with a first silicon powder receiver and a second silicon powder receiver. The first silicon powder receiver is connected to the bottom of the cyclone separator to collect coarse silicon powder; the second silicon powder receiver is connected to the bottom of the silicon powder filter to collect fine silicon powder. The collected silicon powder can be further processed for resource recovery, and the coarse silicon powder can be reused as a supplementary feedstock in the fluidized bed reactor, improving feedstock utilization and reducing waste emissions.

[0082] In this embodiment, S304: The chlorosilane mixed gas output from the filter unit is introduced into the heat exchanger for secondary cooling.

[0083] The chlorosilane mixture gas, after silicon powder removal, is still at a relatively high temperature and needs further cooling to meet the process requirements of the subsequent rapid cooling and washing process. The chlorosilane mixture gas output from the filtration unit is passed into a heat exchanger for secondary cooling. This heat exchanger is a high-efficiency shell-and-tube heat exchanger. Through sufficient heat exchange between the heat exchange medium and the chlorosilane mixture gas, the gas temperature is reduced to 180-220℃. This reduces the load on the subsequent rapid cooling and washing process and also allows for the recovery of waste heat from this stage, which can be used to preheat hydrogen or silicon tetrachloride raw materials, achieving energy cascade utilization and reducing overall energy consumption.

[0084] In this embodiment, S305: The chlorosilane mixed gas output from the heat exchanger is subjected to rapid cooling and washing.

[0085] Even after secondary cooling, the chlorosilane mixture still contains impurities such as metal chlorides and high-boiling-point substances. A rapid cooling and washing process is required to remove these impurities and further reduce the temperature. The chlorosilane mixture output from the heat exchanger is passed into a rapid cooling tower. The chlorosilane liquid, condensed using a cold hydrogenation process, is then sprayed onto the gas. Simultaneously, a multi-layer distributor evenly distributes the spray medium into the rapid cooling tower, ensuring full contact between the spray medium and the chlorosilane mixture. This rapidly lowers the gas temperature (to 100-120℃) and allows high-boiling-point substances such as metal chlorides to fully dissolve in the spray medium, thus removing the impurities.

[0086] The spray liquid containing impurities generated at the bottom of the quench tower is transported through pipelines to a special filter for filtration to remove solid impurities. The filtered slurry is then transported to the slurry system for centralized treatment and discharge in compliance with standards, thus avoiding environmental pollution.

[0087] S306: The chlorosilane mixture gas after rapid cooling and washing is condensed and separated to obtain chlorosilane and hydrogen.

[0088] The chlorosilane mixture gas (containing chlorosilane components, hydrogen, and a small amount of residual impurities) after quenching and washing needs to undergo multi-stage condensation separation to achieve the separation and recovery of chlorosilanes and hydrogen. The specific process is as follows: the chlorosilane mixture gas output from the top outlet of the quench tower is sequentially passed through a circulating hydrogen heat exchanger, a silicon tetrachloride heat exchanger, an air cooler, a circulating water heat exchanger, a chilled water heat exchanger, an intermediate heat exchanger, and a terminal condenser in a preset order for multi-stage gradient condensation.

[0089] Through multi-stage condensation, the chlorosilane components are gradually liquefied to form a condensate, which is then piped to a hydrogenation liquid storage tank as a subsequent raw material for polysilicon production. Hydrogen, due to its extremely low boiling point, remains gaseous during the multi-stage condensation process and is discharged from the outlets of the intermediate heat exchanger and the terminal condenser. The discharged hydrogen is then transported to a circulating hydrogen buffer tank for buffering, and subsequently pressurized by a circulating hydrogen compressor and heated by a circulating hydrogen heat exchanger. After being processed to the pressure and temperature conditions required for the hydrogenation reaction, it is reused in the mixture of materials in process S301, achieving hydrogen recycling and reducing raw material consumption and production costs.

[0090] Furthermore, this application first introduces the chlorosilane mixed gas after the fluidized bed reaction into a coiled tube heat exchanger, utilizing its spiral or corrugated flow channel structure to enhance turbulence and improve heat exchange efficiency. Subsequently, the heat-exchanged mixed gas is sent to a filtration unit, where it undergoes staged separation by a cyclone separator and a silicon powder filter to remove silicon powder impurities carried in the gas. The coiled tube heat exchanger's function is to exchange heat between the reactant chlorosilane mixed gas and the reactants hydrogen and silicon tetrachloride, thereby heating the feed hydrogen and silicon tetrachloride and cooling the reactant chlorosilane mixed gas. The filtration unit filters the reactant chlorosilane mixed gas. Finally, the filtered mixed gas is introduced into a heat exchanger, where heat conduction further reduces the gas temperature, providing stable process conditions for subsequent rapid cooling, washing, and condensation separation processes. The entire process, through the efficient heat transfer of the coiled tube heat exchanger and the pre-positioned design of the filtration unit, ensures that the reactant gas is sufficiently cooled and silicon powder removed before entering subsequent equipment, thus preventing heat exchanger blockage and improving overall process efficiency.

[0091] By replacing traditional shell-and-tube heat exchangers with coiled-tube heat exchangers and placing the filtration unit before the heat exchange step, the problems of low heat exchange efficiency, high energy consumption, and equipment blockage in existing technologies are solved. The spiral or corrugated flow channel design of the coiled-tube heat exchanger enhances turbulence and breaks the boundary layer effect between the gas and the heat exchange medium, significantly improving heat transfer efficiency and reducing the power requirement of the electric heater, thus lowering energy consumption. Simultaneously, the pre-positioning of the filtration unit, through the staged separation of a cyclone separator and a silicon powder filter, thoroughly removes silicon powder impurities from the gas, preventing their deposition and scaling inside the heat exchanger, extending equipment lifespan, and reducing maintenance frequency. Furthermore, the filtered gas is further cooled in the heat exchanger, ensuring the stability of subsequent quenching, washing, and condensation separation processes, thereby optimizing the continuity and efficiency of the overall process. This technology, through the combination of thermodynamic optimization and mechanical protection, achieves a dual improvement in energy utilization and equipment stability in the cold hydrogenation process, providing a highly efficient, energy-saving, and sustainable solution for large-scale industrial production.

[0092] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2The chlorosilane mixture gas output from the coiled tube heat exchanger will be filtered to remove silicon powder, including:

[0093] The filtration unit includes a cyclone separator and a silica powder filter connected in sequence;

[0094] The chlorosilane mixed gas output from the coiled tube heat exchanger is fed into a cyclone separator for gas-solid separation to remove silicon powder;

[0095] The chlorosilane mixture gas after gas-solid separation is passed into a silicon powder filter to remove silicon powder.

[0096] In this embodiment, the filtration unit adopts a staged filtration design, consisting of a cyclone separator and a silica powder filter connected in sequence. The two are connected in series through a sealed pipeline to form a two-stage filtration system of coarse and fine filtration, ensuring the silica powder removal effect. The cyclone separator is connected to the gas outlet of the coiled tube heat exchanger, and the gas outlet of the silica powder filter is connected to the inlet of the heat exchanger in the subsequent secondary cooling process. The overall process is seamlessly connected, with no risk of gas leakage.

[0097] Step 1: Cyclone separator for coarse filtration and desiliconization.

[0098] The chlorosilane mixture, after being cooled in the first stage by a coiled-tube heat exchanger (to 380-420℃), is directly introduced into a cyclone separator through a sealed pipe. This cyclone separator employs a conical cavity structure and utilizes centrifugal force separation. When the chlorosilane mixture enters the separator at a preset flow rate, the centrifugal force generated by the rotation of the cavity throws larger silicon powder particles (≥10μm) against the inner wall of the cavity, causing them to settle to the bottom of the separator, achieving preliminary gas-solid separation and removing most of the coarse silicon powder. The separated gas exits from the top outlet of the cyclone separator and enters the next filtration stage.

[0099] Step 2: Fine filtration and desiliconization using a silicon powder filter.

[0100] The chlorosilane mixture gas, after coarse filtration by the cyclone separator, still retains a small amount of fine silicon powder with a particle size of less than 10 μm, requiring fine filtration through a silicon powder filter. The silicon powder filter is internally configured with multiple layers of high-precision filter screens, with the screen pore size decreasing progressively along the gas flow direction (preferably 20 μm, 10 μm, and 5 μm), allowing for targeted interception of fine silicon powder of different particle sizes. As the mixture gas flows through the filter screens, the fine silicon powder is firmly adsorbed onto the screen surface. The filtered clean chlorosilane mixture gas exits from the filter outlet and enters the subsequent heat exchanger for a secondary cooling process.

[0101] Furthermore, the filtration unit includes a first silicon powder receiver and a second silicon powder receiver, the first silicon powder receiver being connected to the cyclone separator and the second silicon powder receiver being connected to the silicon powder filter;

[0102] The silicon powder removed by the cyclone separator and silicon powder filter enters the first silicon powder receiver and the second silicon powder receiver.

[0103] The first silicon powder receiver adopts a sealed tank structure, connected to the bottom discharge port of the cyclone separator via a bottom outlet pipe. A high-temperature resistant sealing valve is installed at the connection point to prevent leakage of the chlorosilane mixture and to control the silicon powder discharge rate. The second silicon powder receiver is also a sealed tank, sealed to the bottom discharge port of the silicon powder filter. The tank volume is designed to be adapted to the filter's powder capacity, meeting the silicon powder storage requirements of continuous production. Both receivers are equipped with pressure monitoring instruments and discharge control valves, enabling visualized control of the silicon powder collection process.

[0104] For example, the first silicon powder receiver collects coarse silicon powder:

[0105] After the chlorosilane mixture is coarsely filtered by a cyclone separator, coarse silicon powder with a particle size ≥10μm settles to the bottom of the cyclone separator under centrifugal force. At this time, the sealing valve on the connecting pipe between the first silicon powder receiver and the cyclone separator is opened, and the coarse silicon powder falls into the first silicon powder receiver under gravity. During the collection process, the internal pressure of the receiver is monitored in real time by a pressure monitoring instrument to ensure that it is balanced with the internal pressure of the cyclone separator, and to avoid pressure fluctuations affecting the gas-solid separation effect. When the silicon powder in the receiver reaches the preset level, the connecting valve is closed and the bottom discharge valve is opened to discharge the coarse silicon powder to subsequent processing equipment.

[0106] The second silicon powder receiver collects fine silicon powder:

[0107] Fine silicon powder particles with a diameter <10μm, intercepted by the silicon powder filter, will gradually accumulate on the filter screen surface and at the bottom of the filter. Through periodic backflushing or gravity settling, the fine silicon powder falls into the powder collection chamber at the bottom of the filter, and then enters the second silicon powder receiver through a connecting pipe. The sealed design of the second silicon powder receiver prevents the fine silicon powder from flying away, and also prevents outside air from entering the filtration system and affecting the purity of the chlorosilane gas. During the collection process, the discharge valve is opened periodically to discharge the fine silicon powder according to the operating time of the silicon powder filter, ensuring that there is no silicon powder accumulation inside the filter and maintaining the filter screen filtration efficiency.

[0108] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2 The chlorosilane mixture gas output from the heat exchanger will be subjected to rapid cooling and scrubbing, including:

[0109] The chlorosilane mixed gas output from the heat exchanger is passed into the quench tower for quenching and washing.

[0110] The chlorosilane liquid condensed by the cold hydrogenation process is sprayed.

[0111] The composite spray medium is evenly sprayed into the quench tower through a multi-layer distributor to achieve cooling and impurity removal.

[0112] In this embodiment, the quench tower adopts a vertical tower structure with a gas inlet and outlet at the top and a spray liquid collection chamber and slag discharge port at the bottom. The multi-layer distributor is arranged in stages from top to bottom along the height of the tower to ensure that the spray medium and the gas are in full contact. The impurity filter is connected to the slag discharge port at the bottom of the quench tower and is subsequently connected to the slurry system to achieve centralized treatment of impurities.

[0113] Chlorosilane mixed gas introduction: The chlorosilane mixed gas, after being cooled in two stages by a heat exchanger (temperature reduced to 180-220℃), is introduced into the quench tower through a sealed pipeline from the top inlet. During the introduction process, the gas flow rate is regulated by a flow control valve to ensure that the gas residence time in the tower meets the washing requirements, avoiding insufficient washing due to excessive flow rate, while maintaining stable pressure inside the tower (matching the upstream process pressure, approximately 2.5-2.9 MPa).

[0114] Spray medium preparation and spraying: The chlorosilane liquid condensed by the cold hydrogenation process is used for spraying. The spray medium is transported to the multi-layer distributor in the quench tower by the spray pump. The distributor sprays the spray medium evenly into a mist through the uniformly distributed nozzles, covering the entire cross section of the tower from top to bottom, and forming a counter-contact with the chlorosilane mixed gas flowing from bottom to top.

[0115] Cooling and impurity removal: The mist spray medium comes into full contact with the high-temperature chlorosilane mixed gas, rapidly absorbing heat from the gas through heat exchange, reducing the gas temperature from 180-220℃ to 100-120℃, creating suitable operating conditions for the subsequent condensation and separation process. The spray liquid and adsorbed impurities after the reaction settle into the collection chamber at the bottom of the quench tower.

[0116] Further, the impurities are transported to a filter for filtration before being transported to the slurry system.

[0117] For example, the spray liquid (slurry) containing impurities in the collection chamber at the bottom of the quench tower is transported to an impurity filter via a slag discharge pump. The filter uses a high-precision filter screen (pore size ≤ 5μm) to intercept solid impurities. The filtered clear liquid can be returned to the spray medium preparation tank for recycling, improving resource utilization. The intercepted solid impurities accumulate in the filter. The slag discharge valve is periodically opened to transport the impurities to the slurry system. After solidification and harmless treatment by the slurry system, the impurities are discharged in compliance with standards, avoiding environmental pollution.

[0118] The clean chlorosilane mixture gas, after being quenched, washed, and impurities removed, is discharged from the top outlet of the quench tower and transported through a sealed pipeline to the subsequent condensation and separation process, where it enters the circulating hydrogen heat exchanger to start multi-stage condensation operations.

[0119] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2 The chlorosilane mixture gas after rapid cooling and washing is condensed and separated, including:

[0120] The chlorosilane mixture gas output from the top outlet of the quench tower undergoes multi-stage condensation and separation through a circulating hydrogen heat exchanger, a silicon tetrachloride heat exchanger, an air cooler, a circulating water heat exchanger, a chilled water heat exchanger, an intermediate heat exchanger, and a terminal condenser.

[0121] Hydrogen is output from the intermediate heat exchanger and the terminal condenser;

[0122] The condensate, after undergoing multi-stage condensation and separation, is discharged into the hydrogenated liquid storage tank.

[0123] In this embodiment, the components are configured sequentially according to the gas flow direction: a circulating hydrogen heat exchanger, a silicon tetrachloride heat exchanger, an air cooler, a circulating water heat exchanger, a chilled water heat exchanger, an intermediate heat exchanger, and a terminal condenser. Each device is connected sequentially via sealed pipelines, with the inlet connected to the top outlet of the quench tower. The outlets correspond to the hydrogenated liquid storage tank (condensate recovery) and the hydrogen recovery pipeline, respectively, forming a complete system for gradient cooling, component separation, and material recovery. All equipment is equipped with temperature and pressure monitoring instruments to monitor the condensation conditions in real time, ensuring stable separation performance.

[0124] Multi-stage gradient condensation operation: The chlorosilane mixed gas (temperature 100-120℃, containing chlorosilane components, hydrogen and a small amount of residual light impurities) after rapid cooling and washing is discharged from the top outlet of the rapid cooling tower through a sealed pipe and sequentially fed into each stage of condensation equipment for gradient cooling and separation.

[0125] The first stage uses a circulating hydrogen heat exchanger to perform preliminary heat exchange using the low-temperature characteristics of the hydrogen to be recovered, reducing the gas temperature to 60-70℃, and some high-boiling chlorosilane components begin to pre-condense. The second stage enters a silicon tetrachloride heat exchanger, where it exchanges heat with the low-temperature silicon tetrachloride raw material, reducing the temperature to 40-50℃, further improving the chlorosilane condensation efficiency, and preheating the silicon tetrachloride raw material to achieve energy recovery. The third stage passes through an air cooler, where forced air heat exchange cools the gas to 30-35℃, liquefying a large amount of chlorosilane components. The fourth stage uses a circulating water heat exchanger, where circulating water reduces the gas temperature to 20-25℃, enhancing the condensation effect. The fifth stage passes through a chilled water heat exchanger, which cools the gas to 5-10℃, retaining most of the remaining low-boiling chlorosilane components. The sixth stage passes through an intermediate heat exchanger, which cools the gas to 0-5℃, further separating trace amounts of chlorosilane. The seventh stage passes through a terminal condenser (using a low-temperature refrigerant), which cools the gas to -10 to 0℃, achieving deep condensation of the chlorosilane components.

[0126] Hydrogen and condensate separation and recovery: After multi-stage condensation, the chlorosilane components are almost completely liquefied to form condensate, which is collected along the drain pipes at the bottom of each piece of equipment and finally discharged into the hydrogenated liquid storage tank for storage as raw materials for subsequent processes in polysilicon production, ensuring that the product purity meets the standards (chlorosilane purity ≥ 99.5%).

[0127] Because of its extremely low boiling point (approximately -252.77°C at normal pressure), hydrogen remains in a gaseous state throughout the multi-stage condensation process. It only participates in energy exchange as a heat exchange medium in each stage of the heat exchanger. Finally, it is discharged from the top outlet of the intermediate heat exchanger and the terminal condenser and enters the hydrogen recovery pipeline. After subsequent pressurization and heating treatment, it is recycled back to the hydrogenation reaction process.

[0128] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2 The hydrogen discharged from the intermediate heat exchanger and terminal condenser will be transported to the circulating hydrogen buffer tank.

[0129] The circulating hydrogen buffer tank is connected in sequence to the circulating hydrogen compressor and the circulating hydrogen heat exchanger.

[0130] In this embodiment, the circulating hydrogen buffer tank serves as the core buffer unit for hydrogen recovery, and is connected to the hydrogen outlets of the intermediate heat exchanger and the terminal condenser via sealed pipelines. The outlet of the circulating hydrogen buffer tank is connected in series with the circulating hydrogen compressor and the circulating hydrogen heat exchanger, and finally connected to the raw material gas mixing pipeline of the cold hydrogenation reaction process to achieve closed-loop hydrogen circulation. All equipment and pipelines are made of corrosion-resistant materials, suitable for high-pressure hydrogen transportation conditions, and prevent gas leakage and equipment corrosion.

[0131] Hydrogen Collection and Buffering / Pressure Stabilization: After multi-stage condensation and separation, hydrogen (purity ≥99.9%, temperature -10 to 5℃, pressure slightly lower than the system operating pressure) discharged from the top outlets of the intermediate heat exchanger and terminal condenser is collected into the main recovery pipeline through two independent sealed pipelines and transported to the circulating hydrogen buffer tank. The circulating hydrogen buffer tank adopts a horizontal sealed tank structure and has dual functions of buffering and pressure stabilization, which can effectively alleviate pressure fluctuations during hydrogen transportation and avoid the impact of pressure shocks on the operation of subsequent equipment. The tank is equipped with a pressure sensor and a level gauge to monitor the pressure and hydrogen storage in the tank in real time. When the pressure is higher than the preset value (preferably 0.1-0.2MPa), the pressure is appropriately released through the pressure relief valve; when the pressure is lower than the preset value, the front-end condensation equipment is linked to adjust the operating conditions to ensure stable hydrogen input.

[0132] Hydrogen pressurization: Hydrogen stored in the circulating hydrogen buffer tank is transported to the circulating hydrogen compressor via the outlet pipeline. Based on the hydrogen pressure requirements (2.5-2.9 MPa) of the cold hydrogenation reaction process, the hydrogen is pressurized by the circulating hydrogen compressor to a pressure matching the reaction conditions. The compressor employs variable frequency control, allowing for flexible adjustment of pressurization power and output flow rate according to the hydrogen storage capacity in the buffer tank and downstream process requirements. This ensures pressure compliance while avoiding energy waste. During pressurization, the compressor's integrated cooling system cools the hydrogen to prevent changes in hydrogen properties due to pressurization and temperature increases, ensuring effective subsequent heat exchange treatment.

[0133] Hydrogen pretreatment heating: Pressurized hydrogen is piped to a circulating hydrogen heat exchanger. The circulating hydrogen heat exchanger employs a high-efficiency heat exchange structure, utilizing waste heat from the cold hydrogenation process (such as waste heat from the quench tower outlet gas and condensate) as the heat exchange medium to heat the hydrogen, raising its temperature to a range matching the reaction feed gas (565-590℃), providing suitable temperature conditions for subsequent hydrogenation reactions. Heating hydrogen through waste heat recovery replaces traditional electric heating, significantly reducing process energy consumption and improving energy utilization. During the heat exchange process, a temperature sensor monitors the hydrogen outlet temperature in real time, triggering a flow control valve on the heat exchanger to precisely adjust the heating temperature, ensuring temperature fluctuations are controlled within ±5℃.

[0134] Hydrogen recycling: After being pressurized and heated for pretreatment, hydrogen is transported through a sealed pipeline to the raw material gas mixing pipeline of the cold hydrogenation reaction process. It is mixed with fresh hydrogen and vaporized silicon tetrachloride to form a mixture that meets the reaction requirements. The mixture is then fed into the fluidized bed reactor to participate in the hydrogenation reaction, completing the closed-loop circulation of hydrogen.

[0135] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2 A mixture of hydrogen, silicon tetrachloride, and silicon powder is fed into a fluidized bed reactor for a hydrogenation reaction, including:

[0136] The mixture is sequentially passed through a quench tower top heat exchanger, a silicon tetrachloride vaporizer, a reaction feed heater, and an electric heater for multi-stage heating and vaporization.

[0137] In this embodiment, the following components are configured sequentially according to the material flow direction: a quench tower top heat exchanger, a silicon tetrachloride vaporizer, a reaction feed heater, an electric heater, and a fluidized bed reactor. All equipment is connected in series via high-temperature resistant and corrosion-resistant sealed pipelines, forming a continuous operation system. The quench tower top heat exchanger utilizes waste heat for initial heating; the silicon tetrachloride vaporizer completes the material vaporization transformation; the reaction feed heater and electric heater precisely control the reaction temperature; and the fluidized bed reactor provides the core reaction space for the hydrogenation reaction, equipped with a copper chloride catalyst dosing device to ensure efficient reaction. All equipment is equipped with temperature and pressure monitoring instruments and control valves, enabling full-process controllability.

[0138] For example, the pretreatment and proportioning of the mixture are as follows: First, the raw materials are pretreated: hydrogen is dehydrated and deoxygenated to ensure a purity ≥99.99%, preventing impurities from affecting reaction efficiency and product quality; silicon tetrachloride is treated to remove mechanical impurities and high-boiling substances, ensuring the material purity meets standards. After pretreatment, hydrogen, silicon tetrachloride, and silicon powder are mixed according to a preset reaction ratio to form a mixture. During mixing, the feed rates of the two raw materials are precisely controlled by a flow metering valve to maintain a stable proportion, laying the foundation for subsequent reactions.

[0139] Multi-stage heating and vaporization treatment: The mixture enters the multi-stage heating and vaporization system, passing through each heating device in sequence to achieve temperature gradient enhancement and full vaporization.

[0140] First stage heating: The mixed material is fed into the heat exchanger at the top of the quench tower, where the residual heat of the gas discharged from the top of the quench tower is used for heat exchange, raising the material temperature from room temperature to 150-180℃, achieving initial heating. At the same time, the process waste heat is recovered, reducing overall energy consumption. After preheating, the material initially presents a gas-liquid mixed state.

[0141] Second-stage vaporization: The preheated mixture enters the silicon tetrachloride vaporizer, where the temperature is raised to 250-300℃ by steam heating or auxiliary heating with waste heat from the process, so that the silicon tetrachloride is completely vaporized and the mixture is converted into a gaseous mixture, thus preventing liquid materials from entering subsequent equipment and affecting the heat exchange effect and reaction stability.

[0142] Third-stage heating: The gaseous mixture is fed into the reaction feed heater and further heated to 450-500℃, gradually approaching the temperature required for the hydrogenation reaction. At the same time, the efficient heat exchange structure of the heater ensures that the material temperature is uniform and there is no excessive local temperature difference.

[0143] Fourth-stage precise temperature control: After being heated by the reaction feed heater, the material is passed through an electric heater for final heating, precisely controlling the temperature to 565-590℃, perfectly matching the temperature requirements of the hydrogenation reaction. The electric heater adopts a variable frequency temperature control mode, which can adjust the heating power in real time according to the temperature feedback of the front-end material, ensuring that the temperature fluctuation of the outlet material is controlled within ±5℃, providing stable temperature conditions for the reaction.

[0144] Hydrogenation reaction proceeds as follows: A gaseous mixture reaching the reaction temperature is introduced into a fluidized bed reactor through a sealed pipeline. Simultaneously, a copper chloride catalyst is added to the reactor. Under a preset high-pressure condition (2.5-2.9 MPa), hydrogen, silicon tetrachloride, and silicon powder undergo a hydrogenation reaction in the presence of the catalyst. A stirring device within the reactor ensures sufficient contact between the materials and the catalyst, enhancing the reaction process and generating a chlorosilane mixture containing components such as trichlorosilane, silicon tetrachloride, and dichlorosilane. During the reaction, the temperature, pressure, and catalyst activity within the reactor are monitored in real time. The catalyst is replenished or replaced periodically to ensure the continuous and efficient progress of the reaction. The generated chlorosilane mixture is discharged from the reactor outlet and proceeds to the subsequent primary cooling process.

[0145] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2 External silicon powder is transported to a cold hydrogenation reactor via a silicon powder collector and a silicon powder feeder to undergo a hydrogenation reaction with multi-stage heated hydrogen and silicon tetrachloride.

[0146] In this embodiment, the following components are configured sequentially according to the silicon powder flow direction: an external silicon powder storage bin, a silicon powder collector, a silicon powder feeder, a quantitative conveying pump, a feeding pipeline, and a cold hydrogenation reactor (fluidized bed reactor). All equipment is connected in series via sealed pipelines, forming a complete system for storage, buffering, quantitative conveying, and precise feeding. The silicon powder collector temporarily stores external silicon powder and is equipped with a dust removal device to prevent silicon powder from flying away. The silicon powder feeder is equipped with a liquid level monitoring and stirring device to prevent silicon powder agglomeration and ensure conveying stability. The quantitative conveying pump uses frequency conversion control to precisely adjust the silicon powder feeding amount. The feeding pipeline is made of high-temperature resistant and wear-resistant material, extending to the interior of the cold hydrogenation reactor and equipped with an atomizing nozzle to ensure thorough mixing of silicon powder and materials.

[0147] For example, external silicon powder pretreatment and storage: The external silicon powder needs to be pretreated to remove mechanical impurities, large particle clumps, and moisture, ensuring that the silicon powder purity is ≥99% and the particle size is uniform (preferably 5-10μm), to avoid impurities affecting the reaction effect and equipment blockage. The pretreated silicon powder is then transported to a silicon powder storage silo for temporary storage. During storage, the silo is kept dry and sealed to prevent the silicon powder from absorbing moisture, deteriorating, or reacting with air.

[0148] Silicon powder grading and buffering: Silicon powder in the storage silo is introduced into the silicon powder collector via gravity conveying or negative pressure conveying. The silicon powder collector activates a dust removal device to capture fine silicon powder particles flying during the conveying process, reducing material waste and preventing silicon powder pollution. After the silicon powder in the collection tank reaches the preset level, it is slowly conveyed to the silicon powder feeder through the discharge valve. The stirring device in the feeder tank continuously operates at a low speed to break up the silicon powder agglomerates and maintain the silicon powder in a loose state, laying the foundation for subsequent quantitative conveying. At the same time, the feeder tank is equipped with a pressure monitoring instrument to ensure that the pressure inside the tank is balanced with the pressure of the conveying system, avoiding conveying interruptions caused by pressure fluctuations.

[0149] Quantitative silicon powder delivery: Based on the requirements of the cold hydrogenation reaction, the silicon powder delivery rate is controlled by a variable frequency quantitative delivery pump to ensure that the silicon powder, multi-stage heated hydrogen, and silicon tetrachloride mixture are fed in a preset ratio. During the delivery process, the silicon powder delivery volume is monitored in real time by a flow sensor, and the feedback is sent to the control system to dynamically adjust the delivery pump frequency, ensuring that the feeding accuracy error is controlled within ±2%. The silicon powder is delivered to the cold hydrogenation reactor through a wear-resistant feeding pipeline, which is insulated throughout to prevent ambient temperature from affecting the flowability of the silicon powder.

[0150] Silicon powder reacts and fuses with the mixture: Silicon powder is sprayed into the cold hydrogenation reactor in a uniform mist form through an atomizing nozzle at the end of the feeding pipe, ensuring full contact with the hydrogen-silicon tetrachloride gaseous mixture that has undergone multi-stage heating (565-590℃) and pressurization (2.5-2.9MPa). A stirring device within the reactor enhances material agitation, and under the catalysis of copper chloride, the silicon powder and the mixture synergistically undergo a hydrogenation reaction, further promoting the conversion of silicon tetrachloride into target products such as trichlorosilane, thereby increasing the yield and purity of the chlorosilane mixed gas. During the reaction, the residual amount of silicon powder and the reaction rate within the reactor are monitored in real time, and the amount of silicon powder fed is dynamically adjusted to ensure stable reaction equilibrium.

[0151] Tail gas and by-product treatment connection: After silicon powder participates in the reaction, the generated chlorosilane mixed gas and the trace amount of unreacted silicon powder are discharged from the reactor outlet together and enter the subsequent first-stage cooling process of the coiled tube heat exchanger. The unreacted silicon powder will be removed in the subsequent filtration unit to achieve closed-loop material control.

[0152] See Figure 2 A cold hydrogenation production apparatus, employing the aforementioned cold hydrogenation production process, includes:

[0153] A coiled tube heat exchanger, with a spiral or corrugated flow channel, is used for staged heating of a mixture of hydrogen and silicon tetrachloride.

[0154] A fluidized bed reactor, connected to the output end of a coiled tube heat exchanger, is used for hydrogenation reactions under the action of a catalyst;

[0155] The filtration structure includes a cyclone separator and a silicon powder filter connected in sequence, for removing silicon powder from the mixed gas;

[0156] A heat exchanger, connected to the output of the filter structure, is used to cool the filtered gas mixture.

[0157] A quench tower, connected to the output of a heat exchanger, is used to quench and wash a mixed gas.

[0158] In this embodiment, the coiled tube heat exchanger adopts a spiral or corrugated flow channel structure, which significantly enhances fluid turbulence and improves the heat transfer coefficient and efficiency compared to traditional shell-and-tube heat exchangers, enabling staged heating of the mixture of hydrogen and silicon tetrachloride. The main body of the equipment is made of stainless steel, and the inner wall of the flow channel is smooth and corrosion-resistant, avoiding material residue and corrosion loss.

[0159] The inlet of the coiled tube heat exchanger is sealed and connected to the outlet of the front-end material pretreatment and multi-stage heating system (quench tower top heat exchanger, silicon tetrachloride vaporizer, reaction feed heater, electric heater), receiving the hydrogen-silicon tetrachloride mixture after being vaporized by step-by-step heating; the outlet is sealed and connected to the inlet of the fluidized bed reactor, stably delivering the mixture heated to the reaction temperature (565-590℃) into the reactor, providing temperature assurance for the hydrogenation reaction.

[0160] The fluidized bed reactor, as the core site of the hydrogenation reaction, adopts a vertical fluidized bed structure and is equipped with a catalyst feeding device, a stirring device, and a temperature and pressure monitoring module. Copper chloride is selected as the catalyst, which can efficiently catalyze the hydrogenation reaction of hydrogen, silicon tetrachloride, and silicon powder to generate a chlorosilane mixed gas. A material distributor is located at the bottom of the reactor to ensure uniform contact between the mixture and the catalyst, enhancing the reaction effect; a gas outlet is located at the top to discharge the generated chlorosilane mixed gas.

[0161] The inlet of the fluidized bed reactor is connected to the outlet of the electric heater, and the outlet of the coiled tube heat exchanger is connected to the inlet of the electric heater. An external silicon powder feeding interface is also reserved to connect with the conveying pipeline of the silicon powder feeder to receive external silicon powder to participate in the reaction. The outlet is connected to the inlet of another set of heat exchange channels of the coiled tube heat exchanger to transport the high-temperature chlorosilane mixed gas after the reaction to the coiled tube heat exchanger for primary cooling treatment, so as to realize the reuse of equipment functions and efficient energy utilization.

[0162] The filtration structure employs a staged design of coarse and fine filtration, consisting of a cyclone separator and a silicon powder filter connected in sequence, along with a first silicon powder receiver, a second silicon powder receiver, and a sealed powder discharge pipeline, achieving efficient removal and centralized collection of silicon powder. The cyclone separator uses a conical cavity structure to separate coarse silicon powder using centrifugal force; the silicon powder filter is internally equipped with multiple layers of high-precision filter screens with progressively smaller pore sizes to specifically intercept fine silicon powder, ensuring that the cleanliness of the filtered gas meets the standards.

[0163] The input end of the filter structure is connected to the output end of the coiled tube heat exchanger (first-stage cooling channel) to receive the chlorosilane mixed gas after the first-stage cooling; the cyclone separator and the silicon powder filter are connected in series through a sealed pipe, and the output end of the silicon powder filter is connected to the input end of the heat exchanger to transport the clean chlorosilane mixed gas after removing silicon powder to the subsequent cooling process, so as to avoid silicon powder entering the downstream equipment and causing blockage and loss.

[0164] The heat exchanger employs a high-efficiency shell-and-tube structure. Its core function is to perform secondary cooling of the filtered chlorosilane mixture, reducing the load on the subsequent quenching and washing process. Simultaneously, it recovers heat for preheating upstream materials, improving energy efficiency. The equipment is equipped with temperature monitoring instruments and a heat exchange medium flow control valve, allowing for precise regulation of the outlet gas temperature to ensure it meets the requirements of the quenching and washing process.

[0165] The input end of the heat exchanger is connected to the output end of the silica powder filter in the filtration structure to receive clean chlorosilane mixed gas; the output end is sealed to the input end of the quench tower to transport the mixed gas after two-stage cooling (from 180-220℃ to 80-100℃) to the quench tower, creating suitable working conditions for impurity removal.

[0166] The quench tower adopts a vertical tower structure and is equipped with a spray medium preparation tank, a multi-layer distributor, an impurity filter, and a slurry conveying pipeline. Its core function is to rapidly cool and scrub the chlorosilane mixed gas after secondary cooling, achieving rapid cooling and removal of impurities such as metal chlorides and high-boiling substances. The multi-layer distributor is arranged in stages along the height of the tower, which can evenly spray the chlorosilane condensate into a mist, allowing it to fully contact the gas in the opposite direction, thus improving the scrubbing effect.

[0167] The input end of the quench tower is connected to the output end of the heat exchanger to receive the chlorosilane mixed gas to be washed; the top outlet of the quench tower is connected to the subsequent multi-stage condensation and separation system (circulating hydrogen heat exchanger, silicon tetrachloride heat exchanger, etc.) to discharge the clean gas after quench washing; the bottom slag discharge port is connected to the impurity filter to transport the spray liquid containing impurities to the filter for treatment, and then introduce it into the slurry system for centralized treatment to achieve environmental compliance.

[0168] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0169] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "a" or "the" can also be understood to convey either singular or plural usage.

[0170] It should be readily understood that the terms “on,” “above,” and “on top of” in this application should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on something” but also “on something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0171] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations (rotated 90° or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0172] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cold hydrogenation production process, characterized in that, include: A mixture of hydrogen, silicon tetrachloride, and silicon powder is fed into a fluidized bed reactor for hydrogenation to produce a chlorosilane mixture. The chlorosilane mixed gas is passed into a coiled tube heat exchanger for primary cooling. The chlorosilane mixed gas output from the coiled heat exchanger is filtered to remove silicon powder. The chlorosilane mixed gas output from the filter unit is passed into a heat exchanger for secondary cooling; The chlorosilane mixture gas output from the heat exchanger is subjected to rapid cooling and washing; The chlorosilane mixture gas after rapid cooling and washing is condensed and separated to obtain chlorosilane and hydrogen.

2. The cold hydrogenation production process according to claim 1, characterized in that, The process of removing silicon powder from the chlorosilane mixed gas output from the coiled tube heat exchanger by passing it through a filtration unit includes: The filtration unit includes a cyclone separator and a silica powder filter connected in sequence; The chlorosilane mixed gas output from the coiled heat exchanger is passed into the cyclone separator for gas-solid separation to remove silicon powder. The chlorosilane mixture gas after gas-solid separation is passed into the silicon powder filter to remove silicon powder.

3. The cold hydrogenation production process according to claim 2, characterized in that, The filtration unit includes a first silicon powder receiver and a second silicon powder receiver, the first silicon powder receiver being connected to the cyclone separator and the second silicon powder receiver being connected to the silicon powder filter; The silicon powder removed by the cyclone separator and the silicon powder filter enters the first silicon powder receiver and the second silicon powder receiver.

4. The cold hydrogenation production process according to claim 1, characterized in that, The rapid cooling and washing of the chlorosilane mixture gas output from the heat exchanger includes: The chlorosilane mixed gas output from the heat exchanger is passed into a quench tower for quenching and washing. The chlorosilane liquid condensed by the cold hydrogenation process is sprayed. The spray medium is evenly sprayed into the quench tower through a multi-layer distributor to achieve cooling and impurity removal.

5. The cold hydrogenation production process according to claim 4, characterized in that, The impurities are then transported to a filter for filtration and then to the slurry system.

6. The cold hydrogenation production process according to claim 4, characterized in that, The step of condensing and separating the chlorosilane mixture gas after rapid cooling and washing includes: The chlorosilane mixed gas output from the top outlet of the quench tower undergoes multi-stage condensation and separation by sequentially passing through a circulating hydrogen heat exchanger, a silicon tetrachloride heat exchanger, an air cooler, a circulating water heat exchanger, a chilled water heat exchanger, an intermediate heat exchanger, and a terminal condenser. The intermediate heat exchanger and the terminal condenser output hydrogen gas. The condensate that has undergone the multi-stage condensation and separation process is discharged into the hydrogenated liquid storage tank.

7. The cold hydrogenation production process according to claim 6, characterized in that, Hydrogen gas discharged from the intermediate heat exchanger and the terminal condenser is delivered to the circulating hydrogen buffer tank; The circulating hydrogen buffer tank is connected in sequence to the circulating hydrogen compressor and the circulating hydrogen heat exchanger.

8. The cold hydrogenation production process according to claim 1, characterized in that, The process of introducing a mixture of hydrogen gas, silicon tetrachloride, and silicon powder into a fluidized bed reactor for hydrogenation includes: The mixture is sequentially passed through a quench tower top heat exchanger, a silicon tetrachloride vaporizer, a reaction feed heater, and an electric heater for multi-stage heating and vaporization.

9. The cold hydrogenation production process according to claim 8, characterized in that, External silicon powder is transported to a cold hydrogenation reactor via a silicon powder collector and a silicon powder feeder to undergo a hydrogenation reaction with multi-stage heated hydrogen and silicon tetrachloride.

10. A cold hydrogenation production apparatus, characterized in that, Cold hydrogenation production using the cold hydrogenation production process described in any one of claims 1 to 9 includes: A coiled tube heat exchanger, wherein the flow channel of the coiled tube heat exchanger has a spiral or corrugated structure, is used for staged heating of a mixture of hydrogen and silicon tetrachloride. A fluidized bed reactor, connected to the output end of the coiled tube heat exchanger, is used for hydrogenation reaction under the action of a catalyst; The filtration structure includes a cyclone separator and a silicon powder filter connected in sequence, for removing silicon powder from the mixed gas; A heat exchanger, connected to the output end of the filter structure, is used to cool the filtered mixed gas. A quench tower, connected to the output of the heat exchanger, is used to quench and wash the mixed gas.

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