Chlorosilane recovery treatment method and system

Abstract

The embodiment of the invention provides a chlorosilane recovery treatment method and system.The method comprises the steps that a chlorosilane mixed medium left in a filter and a pipeline is conveyed to a gas-liquid separation device in a negative pressure environment to be subjected to gas-liquid separation, and the separated gas-phase medium is input into a heat exchanger to be subjected to condensation treatment; and inputting the condensed uncondensed gas into a tail gas absorption device for neutralization treatment. By constructing a continuous process of negative pressure conveying, condensation recovery and tail gas neutralization, efficient and safe recovery of chlorosilane is achieved, the problems of material leakage, environmental pollution and safety risks in the filter cleaning process are effectively solved, and the device has the advantages of being high in recovery rate, good in environmental protection property and safe to operate.

Description

Technical Field

[0001] This application relates to the field of polysilicon production technology, and in particular to a method and system for the recovery and treatment of chlorosilane. Background Technology

[0002] In the cold hydrogenation process of polysilicon production, after the chlorosilane mixed gas is rapidly cooled and washed, the residual silicon powder and high-boiling substances need to be intercepted by a filter. During the filter cleaning operation, the highly volatile and corrosive chlorosilane liquid remaining inside the filter is prone to volatilization and dispersion, causing material loss, environmental risks, and safety hazards.

[0003] In related technical solutions, the treatment of filter blockage mainly relies on regular manual disassembly and cleaning, supplemented by local sealing measures in an attempt to reduce leakage.

[0004] However, solutions employing related technologies have significant drawbacks in terms of material recovery, operational efficiency, and system integration: First, volatile gases easily escape into the environment during manual cleaning, and the limited effectiveness of local sealing leads to material loss and causes corrosion, safety, and environmental problems. Second, reliance on manual disassembly results in low operational efficiency, long downtime, and the corrosiveness of chlorosilanes accelerates equipment wear. Third, existing processes lack an integrated design for the efficient collection, condensation, and tail gas treatment of the gas-liquid mixture during the cleaning stage, making it difficult to achieve effective recovery and recycling of chlorosilanes. Summary of the Invention

[0005] This application provides a method and system for the recovery and treatment of chlorosilanes, which can achieve efficient closed-loop recovery of chlorosilanes, reduce leakage risk and equipment blockage probability, reduce environmental pollution, and ensure operational safety.

[0006] In a first aspect, embodiments of this application provide a method for recovering and treating chlorosilanes, comprising:

[0007] The chlorosilane mixture is transported to a gas-liquid separator under negative pressure for gas-liquid separation.

[0008] The gaseous medium separated by the gas-liquid separation device is fed into a heat exchanger for condensation.

[0009] The uncondensed gas after being condensed by the heat exchanger is fed into the tail gas absorption device for neutralization.

[0010] In one possible implementation, the chlorosilane mixture is delivered to the gas-liquid separation device via a vacuum pump.

[0011] In one possible implementation, the step of conveying the chlorosilane mixture to a gas-liquid separator under negative pressure to perform gas-liquid separation includes:

[0012] Pressure changes within the gas-liquid separation device are monitored using a pressure sensor.

[0013] Adjust the pumping rate and / or pressure value of the vacuum pump based on the monitored pressure changes.

[0014] In one possible implementation, monitoring pressure changes within the gas-liquid separator via a pressure sensor includes:

[0015] A first pressure sensor and a second pressure sensor are respectively installed in the bottom region and the top region of the gas-liquid separation device;

[0016] The first pressure sensor is used to detect the pressure of the liquid layer, and the second pressure sensor is used to detect the pressure of the gas layer.

[0017] In one possible implementation, the step of inputting the gaseous medium separated by the gas-liquid separation device into a heat exchanger for condensation treatment includes:

[0018] The heat exchanger includes a first heat exchanger and a second heat exchanger connected in series.

[0019] The gaseous medium is sequentially introduced into the first heat exchanger and the second heat exchanger;

[0020] The first heat exchanger performs a first-stage cooling of the gaseous medium using a first cooling medium.

[0021] The second heat exchanger performs a second-stage condensation of the gaseous medium output from the first heat exchanger using a second cooling medium.

[0022] The temperature of the second cooling medium is lower than the temperature of the first cooling medium.

[0023] In one possible implementation, the first cooling medium comprises cooling water, and the second cooling medium comprises a low-temperature ethylene glycol solution.

[0024] In one possible implementation, the step of inputting the uncondensed gas after condensation by the heat exchanger into the tail gas absorption device for neutralization treatment includes:

[0025] The gas treated by the exhaust gas absorption device is then passed into the adsorption device.

[0026] The adsorbent in the adsorption device adsorbs harmful gases from the gas after it has been treated by the exhaust gas absorption device.

[0027] In one possible implementation, the adsorbent comprises activated carbon or molecular sieve.

[0028] In one possible implementation, a flow regulating valve is provided on the pipeline between the vacuum pump and the gas-liquid separation device;

[0029] The method further includes: dynamically adjusting the negative pressure intensity entering the gas-liquid separation device through the flow regulating valve according to the flow rate of the chlorosilane mixed medium.

[0030] Secondly, embodiments of this application provide a chlorosilane recovery and treatment system, comprising:

[0031] A gas-liquid separation device, wherein the gas-liquid separation device is connected to a negative pressure generating device;

[0032] A heat exchanger, the input end of which is connected to the output end of the gas-liquid separator via a first pipe;

[0033] The exhaust gas absorption device has its input end connected to the output end of the heat exchanger via a second pipe.

[0034] Compared with the prior art, the beneficial effects of this application are at least as follows:

[0035] The recycling method described in this application includes steps of conveying the chlorosilane mixture under negative pressure and performing gas-liquid separation, condensation, and tail gas neutralization. By establishing and maintaining a negative pressure environment to convey the mixture, compared to the manual disassembly and open cleaning methods under normal or positive pressure in related technologies, the highly volatile and corrosive chlorosilane liquid can be effectively prevented from overflowing and spreading during the transfer process. This fundamentally eliminates on-site material leakage, ensures the safety and health of operators, and reduces material waste.

[0036] This application includes a step of inputting the separated gaseous medium into a heat exchanger for condensation. Thus, when the gaseous medium contains condensable chlorosilane components, controlled low-temperature cooling allows for efficient condensation into a liquid, which can then be recovered. Compared to traditional methods that allow this gas to be vented or simply absorbed, this significantly improves the recovery rate of chlorosilane feedstock, achieves resource recycling, and reduces production costs.

[0037] This application includes a step of neutralizing uncondensed gas by introducing it into a tail gas absorption device. This allows any acidic gases (such as hydrogen chloride) and other harmful components that may remain after condensation to be converted into harmless or less harmful substances through a chemical neutralization reaction. Compared to direct emission without treatment, this step significantly reduces the pollution load on the atmosphere and meets stringent environmental emission requirements. Attached Figure Description

[0038] 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.

[0039] Figure 1 The schematic diagram of the chlorosilane recovery and treatment process provided in this application Figure 1 ;

[0040] Figure 2 The schematic diagram of the chlorosilane recovery and treatment process provided in this application Figure 2 ;

[0041] Figure 3 This is a schematic diagram of the cold hydrogenation process provided in this application.

[0042] Explanation of reference numerals in the attached figures:

[0043] 100. Vacuum pump; 200. Heat exchanger; 300. Exhaust gas absorption device.

[0044] The accompanying drawings have illustrated 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 specific embodiments. Detailed Implementation

[0045] 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.

[0046] In the polysilicon production process, the reduction reaction generates a large amount of byproducts such as silicon tetrachloride, which need to be converted into a reusable mixture of chlorosilanes, such as trichlorosilane, through a cold hydrogenation process. This process typically involves the hydrogenation reaction of hydrogen, silicon tetrachloride, and silicon powder under high temperature and pressure conditions. After generating a chlorosilane mixture gas, it undergoes cooling in a quench tower, washing, and multi-stage condensation to finally separate the crude product. However, during filter cleaning, unreacted fine silicon powder and high-boiling-point substances in the reaction system easily deposit in pipes, valves, and filters, leading to blockages and abnormal system pressure. Simultaneously, the residual chlorosilane liquid in the filter is highly volatile and corrosive, easily overflowing and spreading into the work environment during cleaning, causing material waste, equipment corrosion, environmental pollution, and personnel health risks. Traditional methods rely on manual disassembly and cleaning, which is not only inefficient and costly but also poses operational risks.

[0047] In existing cold hydrogenation processes, after the chlorosilane mixed gas is cooled and washed in a quench tower, the residual silicon powder and high-boiling-point substances are temporarily stored in a slurry buffer tank before being transported to the slurry treatment process. During filter cleaning, blockages are typically removed manually. During this process, the residual chlorosilane liquid in the pipes and filters, due to its high volatility, easily overflows during disassembly or maintenance, and its gaseous form rapidly diffuses into the working environment. Current technologies do not provide a systematic solution for chlorosilane recovery during the filter cleaning stage, only reducing leakage through local sealing measures, but with limited effectiveness. Furthermore, the reliance on periodic manual cleaning not only increases downtime and labor costs but also shortens equipment lifespan due to the corrosive nature of chlorosilanes. In addition, the existing recovery process lacks sufficient integration of gas-liquid separation, condensation recovery, and tail gas treatment, making it difficult to achieve efficient closed-loop recovery of chlorosilanes.

[0048] To overcome the shortcomings of existing technologies, this application proposes a method and system for the recovery and treatment of chlorosilanes. By constructing a closed-loop recovery system, a synergistic treatment process involving vacuum pump-driven gas-liquid separation, heat exchange and condensation, and tail gas absorption is utilized to achieve efficient recovery of chlorosilane liquids and volatile gases. Addressing the problems of chlorosilane leakage, equipment blockage, and low recovery efficiency during filter cleaning, this method integrates vacuum negative pressure-driven gas-liquid separation, condensation recovery, and tail gas neutralization, forming a closed-loop process chain. This reduces material loss, lowers environmental risks, and improves system stability.

[0049] This application addresses the issues of leakage, clogging, and low recovery efficiency during the filter cleaning stage of the cold hydrogenation process, proposing the following technical approach: First, the root causes of chlorosilane leakage during filter cleaning are analyzed, revealing that they primarily stem from a lack of vacuum environment and insufficient gas-liquid separation. A vacuum pump is introduced to create a negative pressure environment. A gas-liquid separator utilizes gravity settling to separate chlorosilane liquid and gas, and then heat exchange and condensation technology is combined to convert the volatile gas into liquid for recovery. The gas-liquid separation, heat exchange and condensation, and tail gas absorption modules are connected in series to form a closed-loop recovery system, achieving full-process recovery of chlorosilane and neutralization of tail gas. By adjusting vacuum pump parameters, heat exchanger temperature, and alkali concentration, the synergistic efficiency of each module is optimized, ultimately resulting in a highly efficient and environmentally friendly recovery process.

[0050] 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.

[0051] See Figure 1 , Figure 2 and Figure 3 This application discloses a method for recovering and treating chlorosilanes, comprising:

[0052] S301: The chlorosilane mixture is transported to the gas-liquid separator under negative pressure to perform gas-liquid separation;

[0053] S302: The gaseous medium separated by the gas-liquid separator is fed into a heat exchanger for condensation.

[0054] S303: The uncondensed gas after being condensed by the heat exchanger is fed into the tail gas absorption device for neutralization treatment.

[0055] Chlorosilane mixture: refers to a mixture containing chlorosilane liquid and volatile gas, such as a mixture of trichlorosilane, silicon tetrachloride and hydrogen chloride.

[0056] Vacuum pump: A device used to provide a negative pressure environment, such as a Roots vacuum pump or a screw vacuum pump.

[0057] Gas-liquid separation device: A container that achieves gas-liquid separation through density differences, such as a vertical separation tank with a conical bottom.

[0058] Heat exchanger: A device used for heat exchange, such as a shell-and-tube heat exchanger or a plate heat exchanger.

[0059] Tail gas absorption device: A device that neutralizes gas with alkali solution, such as a packed tower or spray tower.

[0060] In this embodiment, S301: The chlorosilane mixed medium is transported to the gas-liquid separation device under negative pressure environment for gas-liquid separation.

[0061] The directional transport of chlorosilane mixed media is achieved by driving it with negative pressure, while the density difference is used to complete the efficient separation of gas and liquid phases, thus avoiding media leakage and deposition blockage from the source.

[0062] First, a closed negative pressure transport channel is constructed to address the residual chlorosilane mixture (containing chlorosilane liquid, volatile chlorosilane gas, hydrogen chloride, hydrogen, and entrained fine silicon powder and high-boiling substances) in the polycrystalline silicon cold hydrogenation process filter and related pipelines. A continuous negative pressure is provided by a negative pressure generating device (preferably a Roots vacuum pump or screw vacuum pump) to extract the mixture from the filter and pipelines and transport it to the gas-liquid separator. To accommodate fluctuations in media flow rate, a flow regulating valve is added to the pipeline between the negative pressure generating device and the gas-liquid separator. A flow monitoring component collects real-time data on the mixed media flow rate and dynamically adjusts the valve opening to precisely control the negative pressure entering the gas-liquid separator, ensuring stable transport and preventing media splashing due to excessively high negative pressure or obstructed transport due to excessively low negative pressure.

[0063] The gas-liquid separation unit adopts a vertical conical bottom structure and utilizes the principle of gravity sedimentation to achieve gas-liquid separation. To monitor the separation status in real time, a first pressure sensor is installed at the bottom of the unit to detect the pressure of the settled chlorosilane liquid layer; a second pressure sensor is installed at the top to detect the pressure of the separated gas phase medium layer. The pressure sensors transmit real-time monitoring data to the control system, which dynamically adjusts the pumping rate and / or output pressure of the negative pressure generating device based on pressure changes: when the liquid layer pressure increases, indicating increased liquid sedimentation, the pumping rate is appropriately increased to accelerate gas phase extraction; when the gas layer pressure fluctuation exceeds the preset range, the negative pressure intensity is fine-tuned to maintain separation stability. Finally, the denser chlorosilane liquid settles to the bottom of the conical bottom, is collected through the liquid outlet, and is transported to the cold hydrogenation process slurry stage for reuse; silica powder and high-boiling-point substances settle along with the liquid, preventing deposition in the pipelines and separation unit; hydrogen chloride, hydrogen gas, and trace amounts of unsettled chlorosilane gas rise to the top of the unit and are extracted through the gas outlet to the next process.

[0064] In this embodiment, S302: The gaseous medium separated by the gas-liquid separation device is input into the heat exchanger for condensation treatment.

[0065] By employing a multi-stage gradient condensation design, the recovery of chlorosilane components in the gaseous medium is maximized, reducing the load on subsequent tail gas treatment and improving resource utilization.

[0066] The gaseous medium separated in S301 is fed into a heat exchanger through a dedicated pipeline. The heat exchanger adopts a two-stage series structure, including a first heat exchanger and a second heat exchanger that are interconnected. The gaseous medium is sequentially fed into the first heat exchanger and the second heat exchanger according to a preset flow direction to achieve staged cooling and condensation. The first heat exchanger uses a first cooling medium (preferably ambient temperature cooling water) as the heat exchange medium. Through heat conduction, the gaseous medium is cooled in the first stage, and its temperature is lowered to near the condensation point of chlorosilanes, causing most of the chlorosilane gas to condense into liquid. The condensate is collected through the return port at the bottom of the first heat exchanger and flows into the liquid recovery pipeline of S301, and is then transported to the slurry process.

[0067] After being processed by the first heat exchanger, the remaining gaseous medium (containing small amounts of chlorosilane gas, hydrogen chloride, and hydrogen) enters the second heat exchanger. The second heat exchanger uses a second cooling medium (preferably a low-temperature ethylene glycol solution) as the heat exchange medium. The temperature of this cooling medium is lower than that of the first cooling medium, achieving a second stage of deep condensation. The low-temperature environment fully condenses the remaining low-concentration chlorosilane gas into a liquid state, further improving the chlorosilane recovery rate. The condensate is also collected in the recovery pipeline for reuse. Uncondensed gases (mainly hydrogen chloride and hydrogen) are discharged from the outlet of the second heat exchanger and enter the subsequent tail gas treatment process. This two-stage condensation design avoids problems such as equipment frosting and insufficient condensation caused by sudden temperature drops in single-stage condensation, and adapts to the recovery needs of different concentrations of chlorosilane gas.

[0068] In this embodiment, S303: The uncondensed gas after being condensed by the heat exchanger is input into the tail gas absorption device for neutralization treatment.

[0069] This step removes acidic and harmful components from uncondensed gases through a neutralization reaction, combined with deep adsorption purification, to ensure that exhaust gases meet emission standards and reduce environmental risks.

[0070] The uncondensed gas from S302, after condensation, is introduced into the tail gas absorption device through a second pipeline. The tail gas absorption device preferably uses a packed tower structure, filled with corrosion-resistant packing material. An alkaline absorbent liquid is introduced into the tower, and the uncondensed gas and the alkaline absorbent liquid are in countercurrent contact, undergoing a neutralization reaction: hydrogen chloride in the gas reacts with sodium hydroxide to produce sodium chloride and water, completely removing acidic and harmful components. To maintain the efficiency of the neutralization reaction, the tail gas absorption device is equipped with a pH monitoring component and an automatic replenishment system. The system monitors the pH value of the absorbent liquid in real time. When the pH value drops below 8, fresh alkaline absorbent liquid is automatically replenished, while the exhausted absorbent liquid is discharged for compliant treatment.

[0071] To further purify the exhaust gas and remove trace amounts of harmful gases remaining after neutralization (such as hydrogen, unreacted hydrogen chloride, and trace amounts of chlorosilanes), the gas treated by the exhaust gas absorption device is passed into an adsorption device. The adsorption device is filled with adsorbent, preferably activated carbon or molecular sieves. Activated carbon can catalytically oxidize hydrogen into harmless water vapor, while molecular sieves, with their high selective adsorption properties, capture residual hydrogen chloride and trace amounts of chlorosilanes, achieving deep purification of the exhaust gas. The adsorbent can be regenerated through periodic high-temperature desorption and reused, reducing operating costs. Ultimately, the purified exhaust gas meets all environmental emission standards and is safely discharged through the exhaust port.

[0072] The above three steps form a complete closed loop. Through the synergistic effect of negative pressure conveying, graded separation, gradient condensation, and neutralization adsorption, the efficient recovery of chlorosilane mixed media is achieved. At the same time, it solves problems such as leakage, blockage, and environmental risks in the filter cleaning stage, and is suitable for the industrial continuous production needs of polycrystalline silicon cold hydrogenation process.

[0073] This application solves the technical problems of chlorosilane liquid overflow and gas diffusion during traditional filter cleaning by utilizing the negative pressure environment provided by a vacuum pump. The negative pressure of the vacuum pump forces the chlorosilane mixture to be transported to the gas-liquid separation device, avoiding liquid leakage caused by an open environment during equipment disassembly. The gas-liquid separation device achieves efficient gas-liquid separation through density differences, ensuring the collection rate of chlorosilane liquid while reducing the possibility of gas carrying impurities. The condensation treatment of the heat exchanger further converts volatile gases into liquid for recovery, while the neutralization reaction of the tail gas absorption device completely eliminates residual harmful gases. This technology, through the integration of negative pressure drive, gas-liquid separation, and condensation recovery, significantly reduces the risk of chlorosilane leakage, reduces material waste and environmental pollution, and improves the safety and environmental friendliness of filter cleaning operations. Ultimately, this method achieves closed-loop recovery of chlorosilane and harmless treatment of tail gas while ensuring production continuity.

[0074] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2 and Figure 3 The chlorosilane mixed medium is transported to the gas-liquid separation device via vacuum pump 100.

[0075] In this embodiment, the vacuum pump 100 is selected as a Roots vacuum pump or a screw vacuum pump, which is suitable for the highly corrosive and volatile characteristics of the chlorosilane mixed medium. The flow parts of the equipment are made of corrosion-resistant materials (such as Hastelloy or PTFE lining) to avoid corrosion damage to the pump body caused by the medium. At the same time, it has good sealing performance and adopts a dual sealing structure of mechanical seal and labyrinth seal to prevent medium leakage and air infiltration during pump operation, and ensure the stability of the negative pressure environment.

[0076] The rated pumping speed and output negative pressure of vacuum pump 100 need to be adapted to the actual working conditions. Based on the estimated maximum flow rate of the chlorosilane mixed medium and the parameters of pipe length and pipe diameter, select equipment with a pumping speed of 15-40m³ / h and an ultimate vacuum of ≤10Pa. This can meet the pumping requirements of the mixed medium under different degrees of blockage and avoid medium stagnation or poor transportation due to insufficient pumping capacity.

[0077] The delivery system is centered around a vacuum pump 100, and connects a filter, delivery pipeline, flow regulating valve, gas-liquid separator, and control system in series to form a closed delivery loop. The specific connection method is as follows: the reserved interface at the bottom of the filter and the associated pipeline is connected to one end of the delivery pipeline through a special corrosion-resistant flange. The other end of the delivery pipeline is connected to the air inlet of the vacuum pump 100 through the flow regulating valve. The air outlet of the vacuum pump 100 is sealed to the air inlet of the gas-liquid separator through a rigid pipe. The entire pipeline system uses seamless steel pipes, and the interfaces are sealed with fluororubber gaskets to prevent media leakage.

[0078] A pressure monitoring point is added to the pipeline between the vacuum pump 100 and the gas-liquid separation device, and a pressure transmitter is deployed to collect the negative pressure value in the pipeline in real time. At the same time, a flow sensor is installed in the pipeline at the filter outlet to monitor the delivery flow rate of the chlorosilane mixed medium in real time. Both data are transmitted to the central control system to provide a basis for the parameter adjustment of the vacuum pump 100 and the opening control of the flow regulating valve, so as to realize the closed-loop control of the delivery process.

[0079] For example, the conveying process operation flow:

[0080] Pre-treatment stage: Before startup, check the sealing of the entire conveying system, remove residual air and impurities by purging the pipeline with nitrogen to avoid safety risks caused by contact between air and chlorosilane mixed media; check the sealing status of vacuum pump 100, lubricating oil level (screw vacuum pump), and cooling system operation to ensure that the equipment is in normal standby state; adjust the initial opening of the flow regulating valve to 30-50%, prepare the gas-liquid separation device for receiving, and turn on its internal pressure sensor monitoring function.

[0081] Negative pressure establishment and media delivery: The vacuum pump 100 is started. Based on feedback data from the flow sensor, the control system gradually adjusts the opening of the flow regulating valve while simultaneously monitoring the negative pressure value in the pipeline, stabilizing it within the range of -0.08 to -0.095 MPa. Under this negative pressure, the residual chlorosilane mixture (containing chlorosilane liquid, volatile gases, hydrogen chloride, hydrogen, and entrained silicon powder and high-boiling substances) in the filter and pipeline is forcibly extracted and flows directionally along the delivery pipeline, then pressurized and delivered by the vacuum pump 100 to the gas-liquid separation device.

[0082] Operating condition adaptation and adjustment: During the conveying process, if the flow sensor detects a sudden increase in the medium flow rate (due to the accumulation and shedding of silicon powder), the control system automatically increases the opening of the flow regulating valve and appropriately increases the pumping speed of the vacuum pump 100 to maintain stable negative pressure in the pipeline and avoid pipeline impact caused by excessive medium flow rate; if a decrease in flow rate is detected (due to partial blockage in the pipeline), the output negative pressure of the vacuum pump 100 is finely adjusted to increase the adsorption force, and the pressure regulation of the subsequent gas-liquid separation device is linked to ensure the continuity of conveying.

[0083] Shutdown and completion: When the mixed medium in the filter and pipeline has been basically transported, keep the vacuum pump 100 running for 10-15 minutes to remove the residual medium in the pipeline; then turn off the vacuum pump 100, close the flow regulating valve, purge the pipeline again with nitrogen, push the residual trace medium to the gas-liquid separation device, and finally shut down the entire conveying system to complete the conveying operation.

[0084] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2 and Figure 3The process involves conveying a chlorosilane mixture to a gas-liquid separator under negative pressure for gas-liquid separation, including:

[0085] Pressure changes within the gas-liquid separator are monitored using pressure sensors.

[0086] Adjust the pumping speed and / or pressure value of vacuum pump 100 based on the monitored pressure changes.

[0087] Pressure sensor: A device used to monitor the pressure inside a container in real time, such as a capacitive pressure sensor or a piezoresistive pressure sensor.

[0088] Control system: A device that receives pressure sensor signals and adjusts vacuum pump parameters, such as a PLC controller or DCS system.

[0089] In this embodiment, a vacuum pump 100 is used as the negative pressure power source to construct a closed negative pressure delivery and gas-liquid separation integrated process. The core objective is to directionally deliver the residual chlorosilane mixed medium (containing chlorosilane liquid, volatile gas, hydrogen chloride, hydrogen, and entrained silicon powder and high-boiling substances) in the filter and related pipelines to the gas-liquid separation device in a negative pressure environment. The gas-liquid two-phase separation is completed by relying on the principle of gravity sedimentation. At the same time, the pumping rate and / or output pressure of the vacuum pump 100 are reversed by real-time monitoring of pressure changes in the gas-liquid separation device to ensure that the separation process is stable and efficient, and to avoid problems such as media leakage, deposition blockage and insufficient separation.

[0090] To accurately capture the pressure dynamics within the gas-liquid separation device, a multi-point pressure sensor layout is adopted to achieve synchronous monitoring of the pressure in the gas-liquid two-phase regions within the device, providing precise data support for the adjustment of vacuum pump 100 parameters.

[0091] Sensor Selection and Installation: Corrosion-resistant, high-precision pressure sensors (preferably capacitive or piezoresistive) are selected to accommodate the highly corrosive nature of the chlorosilane mixture. The sensor probes are made of Hastelloy alloy, and the sealing structure uses PTFE seals to prevent media corrosion and leakage. A first pressure sensor is installed in the liquid layer area at the bottom of the gas-liquid separator to monitor the pressure of the settled chlorosilane liquid layer in real time. A second pressure sensor is installed in the gas layer area at the top of the separator to monitor the pressure of the separated gaseous medium in real time. Both sensors are fixed to the separator housing via sealing flanges, with the probes extending into the corresponding media areas to ensure accurate monitoring data.

[0092] Monitoring data transmission and processing: The pressure sensor transmits the pressure signal collected in real time to the central control system. The control system analyzes the two pressure data synchronously, calculates the pressure difference between the liquid layer and the gas layer, and combines the preset pressure threshold (set according to the device volume, medium characteristics and separation requirements) to determine the operating status of the gas-liquid separator, identify abnormal conditions such as medium accumulation, poor separation, and gas phase retention, and provide a basis for decision-making for subsequent parameter adjustment.

[0093] For example, the control system uses pressure sensor monitoring data as the core basis and adopts graded adjustment logic to dynamically adjust the pumping speed and / or output pressure of vacuum pump 100 to ensure that the pressure in the gas-liquid separation device is maintained in the optimal range (gas layer pressure 0.05-0.1MPa, liquid layer pressure 0.2-0.3MPa), thereby achieving a balance between separation efficiency and system stability.

[0094] Normal operating condition adjustment: When the pressure values ​​monitored by the first and second pressure sensors are both within the preset threshold range and the pressure difference is stable, it indicates that the gas-liquid separation process is stable. Vacuum pump 100 maintains the current pumping rate and output pressure to ensure that the medium delivery and separation rhythm are matched.

[0095] Liquid layer pressure abnormality adjustment: If the first pressure sensor detects that the liquid layer pressure exceeds the preset upper limit, it indicates that the amount of chlorosilane liquid settling is too large, and there is a risk of stagnation and accumulation. The control system automatically increases the pumping speed of vacuum pump 100, while fine-tuning the output pressure to accelerate the outgoing speed of the gas phase medium, making room for liquid settling and reducing the liquid layer pressure to within the threshold range. If the liquid layer pressure is lower than the preset lower limit, it indicates that the medium delivery volume is insufficient. The pumping speed of vacuum pump 100 is appropriately reduced to avoid liquid splashing due to excessive negative pressure, which would affect the separation effect.

[0096] Gas layer pressure anomaly adjustment: If the second pressure sensor detects that the gas layer pressure exceeds the preset upper limit, it indicates that the gas phase medium is not being discharged smoothly, which may be due to partial blockage in the pipeline or excessive load on the condensation process. The control system will first fine-tune the output pressure of vacuum pump 100 while maintaining the pumping rate to accelerate the delivery of the gas phase medium. If the pressure still cannot be reduced, the pumping rate will be increased simultaneously to ensure that the gas phase medium is discharged in a timely manner, avoiding pressure rise caused by retention in the device and the risk of leakage. If the gas layer pressure is lower than the preset lower limit, it indicates that the pumping capacity of vacuum pump 100 is excessive, which may cause negative pressure impact in the liquid layer. The control system will appropriately reduce the pumping rate or reduce the output negative pressure intensity to maintain stable gas layer pressure.

[0097] Emergency adjustment under extreme conditions: When the pressure sensor detects a sudden pressure change, indicating an abnormality in the system (such as silicon powder blockage or media leakage), the control system immediately issues an alarm signal and quickly adjusts the parameters of the vacuum pump (such as urgently reducing the pumping rate or cutting off the negative pressure output) to prevent the operating conditions from deteriorating and to buy time for troubleshooting and handling.

[0098] Furthermore, by dynamically adjusting the vacuum pump parameters, the problem of separation efficiency fluctuations caused by traditional fixed vacuum values ​​is solved. Specifically, when the flow rate of the mixed medium suddenly increases, a high vacuum value can accelerate gas-liquid separation, reduce the residence time of silica powder and high-boiling-point substances in the separation device, and reduce the risk of secondary mixing. At the same time, dynamic adjustment reduces the energy consumption of the vacuum pump and extends the equipment life, thereby achieving energy saving and consumption reduction while ensuring separation efficiency.

[0099] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2 and Figure 3 The pressure changes within the gas-liquid separator are monitored using pressure sensors, including:

[0100] A first pressure sensor and a second pressure sensor are respectively installed in the bottom region and the top region of the gas-liquid separation device;

[0101] The first pressure sensor is used to detect the pressure of the liquid layer, and the second sensor is used to detect the pressure of the gas layer.

[0102] In this embodiment, the first pressure sensor is installed at the bottom of the gas-liquid separation device, at a height 5-10 cm below the midline of the liquid layer during normal operation. This ensures the sensor probe is always submerged in the chlorosilane liquid layer, preventing liquid level fluctuations from exposing the probe to the gas phase and affecting monitoring accuracy. The sensor is fixed to the device housing via a corrosion-resistant sealing flange, and the connection between the flange and the housing is sealed with a PTFE gasket to prevent leakage of the chlorosilane medium.

[0103] The second pressure sensor is installed at the top of the gas-liquid separator, 15-20 cm from the top end face, near the gas outlet. It is positioned to avoid direct airflow impact from the gas outlet, preventing airflow disturbances from causing pressure monitoring errors. The sensor is also secured with a corrosion-resistant sealing flange, using the same sealing structure as the first pressure sensor to ensure compatibility with the negative pressure environment and corrosive media within the separator.

[0104] Both pressure sensors are high-precision and corrosion-resistant, with capacitive or piezoresistive pressure sensors preferred. The measurement range is compatible with the operating pressure range of the gas-liquid separation device, and the accuracy class is not lower than 0.5, ensuring the accuracy of pressure change monitoring.

[0105] The sensor probe is made of Hastelloy, which is resistant to corrosion from media such as chlorosilanes and hydrogen chloride, extending its service life. The output signal uses a 4-20mA standard electrical signal, offering strong anti-interference capabilities and long transmission distances, making it suitable for signal transmission needs in industrial settings. Furthermore, the sensor is equipped with temperature compensation to counteract the impact of internal temperature fluctuations on pressure measurement, further enhancing monitoring stability.

[0106] For example, the first pressure sensor is used to detect the pressure of the liquid layer at the bottom of the gas-liquid separation device, and to provide real-time feedback on the sedimentation amount, liquid level, and liquid flow state of the chlorosilane liquid. By observing changes in the liquid layer pressure, it is possible to determine whether there is liquid stagnation or accumulation, abnormal rise or fall in liquid level, etc., providing a core basis for controlling the pumping speed of the vacuum pump 100.

[0107] The second pressure sensor is used to detect the pressure of the gas layer at the top of the gas-liquid separator, providing real-time feedback on the gas phase medium extraction efficiency, gas phase retention, and negative pressure stability within the device. Changes in the gas layer pressure can identify problems such as gas phase pipeline blockage and excessive gas phase medium retention, providing data support for fine-tuning the output pressure of vacuum pump 100.

[0108] The first and second pressure sensors synchronously collect pressure data for their respective areas. After converting the real-time pressure signals into standard electrical signals, they are transmitted to the central control system via shielded cables. The control system independently collects and synchronously stores the two data streams to ensure real-time tracking of pressure changes. Simultaneously, data filtering removes interference signals caused by airflow disturbances and temperature fluctuations, ensuring the authenticity and reliability of the monitoring data and laying the foundation for subsequent process parameter adjustments.

[0109] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2 and Figure 3 The gaseous medium separated by the gas-liquid separator is fed into the heat exchanger 200 for condensation treatment, including:

[0110] Heat exchanger 200 includes a first heat exchanger and a second heat exchanger connected in series.

[0111] The gaseous medium is sequentially introduced into the first heat exchanger and the second heat exchanger;

[0112] The first heat exchanger cools the gaseous medium in the first stage using a first cooling medium.

[0113] The second heat exchanger uses a second cooling medium to perform a second stage of condensation on the gaseous medium output from the first heat exchanger.

[0114] The temperature of the second cooling medium is lower than that of the first cooling medium.

[0115] The first cooling medium includes cooling water, and the second cooling medium includes a low-temperature ethylene glycol solution.

[0116] First heat exchanger: A heat exchange device used for initial cooling, such as a shell-and-tube heat exchanger.

[0117] Second heat exchanger: A heat exchange device used for deep condensation, such as a plate heat exchanger.

[0118] In this embodiment, the heat exchanger 200 is a two-stage series integrated structure. Its core consists of a first heat exchanger and a second heat exchanger that are sealed and connected to each other. The entire structure is made of corrosion-resistant material adapted to the characteristics of the gaseous medium (containing corrosive components such as chlorosilanes and hydrogen chloride). The first and second heat exchangers achieve directional flow of the gaseous medium through dedicated corrosion-resistant pipes. The pipe joints are sealed with fluororubber gaskets to prevent medium leakage and air infiltration. Simultaneously, temperature monitoring points are installed on the connecting pipes of the two heat exchangers to collect real-time gaseous medium temperature data, providing a basis for cooling medium adjustment and forming a complete condensation treatment unit.

[0119] The gaseous medium (a mixture of volatile chlorosilane gas, hydrogen chloride, hydrogen, etc., derived from the top of the gas-liquid separator) flows sequentially through the first heat exchanger and the second heat exchanger according to a preset flow direction, achieving staged condensation through gradient cooling. The specific process is as follows:

[0120] Gas phase medium introduction: The gas phase medium separated by the gas-liquid separation device is directionally transported to the first heat exchanger inlet of heat exchanger 200 through a sealed pipeline. A flow stabilizing valve is installed at the inlet to ensure that the gas phase medium enters the heat exchange system at a uniform flow rate and avoids flow rate fluctuations from affecting the condensation effect.

[0121] First-stage cooling (first heat exchanger): After the gaseous medium enters the first heat exchanger, it undergoes initial cooling through heat exchange with the first cooling medium. The first heat exchanger preferably has a shell-and-tube structure, with the tube bundles made of Hastelloy alloy, which is resistant to corrosive media. The first cooling medium is ambient temperature cooling water (25-35℃), which is circulated to the shell side of the first heat exchanger by a cooling water pump, forming a counter-current heat exchange with the gaseous medium in the tube side, reducing the gaseous medium temperature from 80-100℃ to near the condensation point of chlorosilanes (40-50℃). This stage allows most of the high-concentration chlorosilane gas in the gas phase to condense into a liquid state. The condensate is collected at the condensate outlet at the bottom of the first heat exchanger and flows into the chlorosilane recovery pipeline for reuse in the slurry process.

[0122] Second-stage condensation (second heat exchanger): The remaining gaseous medium (containing a small amount of low-concentration chlorosilane gas, hydrogen chloride, and hydrogen) after initial cooling in the first heat exchanger enters the second heat exchanger through a connecting pipe for deep condensation. The second heat exchanger is a plate heat exchanger, which offers higher heat exchange efficiency and is suitable for the condensation of low-concentration gases. The second cooling medium is a low-temperature ethylene glycol solution, with a temperature (-15 to -25°C) lower than the first cooling medium. A low-temperature refrigeration unit maintains the temperature of the cooling medium. The gaseous medium undergoes thorough heat exchange with the low-temperature ethylene glycol solution in the second heat exchanger, further reducing its temperature to -10 to -15°C. The remaining low-concentration chlorosilane gas is fully condensed into a liquid state, and the condensate is also collected in the recovery pipeline, maximizing the recovery of chlorosilane resources.

[0123] Uncondensed gas removal: After two-stage condensation treatment, the uncondensed gas (mainly hydrogen chloride and hydrogen, without recyclable chlorosilane) is removed from the outlet of the second heat exchanger and transported to the subsequent tail gas absorption device through a dedicated pipeline for neutralization and purification treatment.

[0124] Furthermore, to ensure effective staged condensation, the selection of the cooling medium and temperature control must meet the following requirements:

[0125] Cooling medium selection: The first cooling medium is industrial cooling water, which has the advantages of wide availability, low cost and strong heat exchange stability; the second cooling medium is low temperature ethylene glycol solution, which has a low freezing point and high heat transfer coefficient, can remain liquid in low temperature environment, is suitable for deep condensation requirements, and is not easy to cause corrosion to equipment.

[0126] Temperature gradient control: Strictly control the temperature difference between the two cooling media, ensuring the second cooling media is 40-60°C lower than the first, forming a stable temperature gradient. This prevents equipment frost and pipe blockage caused by sudden temperature drops, while also improving the chlorosilane condensation recovery rate. Temperature sensors monitor the inlet and outlet temperatures of the two cooling media in real time, feeding back the data to the refrigeration unit and cooling water pump control system to dynamically adjust the cooling media flow rate and refrigeration power, maintaining temperature stability.

[0127] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2 and Figure 3 The uncondensed gas after condensation in heat exchanger 200 is fed into tail gas absorption device 300 for neutralization treatment, including:

[0128] The gas after being treated by the exhaust gas absorption device 300 is passed into the adsorption device.

[0129] The harmful gases in the gas treated by the exhaust gas absorption device 300 are adsorbed by the adsorbent in the adsorption device.

[0130] Adsorbents include activated carbon or molecular sieves.

[0131] In this embodiment, the uncondensed gas discharged from heat exchanger 200 mainly consists of hydrogen chloride and hydrogen, mixed with trace amounts of incompletely condensed chlorosilane gas and impurities, which are highly corrosive and pose potential safety risks. This process uses the tail gas absorption device 300 as the core neutralization unit. First, acidic harmful components are removed using an alkaline absorbent, and then the residual trace harmful gases are deeply captured by an adsorption device, forming a two-stage closed-loop treatment of neutralization and adsorption. This ensures that all indicators of the tail gas meet environmental emission standards while avoiding safety hazards caused by gas leaks.

[0132] The entire treatment system adopts a closed pipeline series design. The air inlet of the exhaust gas absorption device 300 and the air outlet of the heat exchanger 200 are sealed and connected through corrosion-resistant pipes. The air outlet of the exhaust gas absorption device 300 is connected to the air inlet of the adsorption device. An exhaust stack is installed at the air outlet of the adsorption device to realize the directional and closed flow of uncondensed gas and prevent secondary leakage.

[0133] The 300 exhaust gas absorption unit features a preferred packed tower structure, offering advantages such as sufficient gas-liquid contact, high neutralization efficiency, and stable operation. The tower body is made of corrosion-resistant material, with the inner wall lined with polytetrafluoroethylene (PTFE), and the interior filled with polypropylene stepped ring packing to increase the gas-liquid contact area. A liquid distributor is installed at the top of the tower to ensure uniform spraying of the alkaline absorbent liquid. A storage tank is located at the bottom for storing and circulating the absorbent liquid, and a level monitor is also provided to monitor the absorbent liquid level in real time.

[0134] For example, the neutralization process flow is as follows:

[0135] Gas introduction: Uncondensed gas discharged from heat exchanger 200 is transported through a sealed pipeline to the bottom inlet of tail gas absorption device 300. As the gas rises along the tower, it forms a counter-current contact with the alkaline absorbent sprayed from the top, ensuring a complete gas-liquid reaction. A gas flow meter is installed at the inlet to monitor the gas flow rate in real time, providing a basis for adjusting the absorbent spray volume.

[0136] Neutralization reaction: The alkaline absorbent is a 10-15% sodium hydroxide solution, which is pumped to the liquid distributor at the top of the tower and sprayed evenly. Hydrogen chloride in the gas neutralizes with the sodium hydroxide to produce harmless sodium chloride and water, completely removing the acidic corrosive components. Trace amounts of uncondensed chlorosilane gas react with the sodium hydroxide solution to form sodium silicate precipitate, which is collected along with the absorbent and flows into the storage tank at the bottom of the tower.

[0137] Absorbent circulation and replenishment: The absorbent in the bottom storage tank is continuously circulated by a circulation pump. The pH value of the absorbent is monitored in real time by an online pH monitor. When the pH value drops below 8, the replenishment valve is automatically opened to replenish the storage tank with fresh sodium hydroxide solution. At the same time, some of the ineffective absorbent (containing sodium silicate precipitate) is discharged. After compliance treatment, it is discharged to maintain the stability of the neutralization reaction efficiency.

[0138] In this embodiment, the adsorption device adopts a fixed-bed adsorption tower structure, which is sealed and connected to the tail gas absorption device 300. The tower body is made of stainless steel, and the inner wall is treated with anti-corrosion. The adsorbent is a composite filling of activated carbon and molecular sieves, with activated carbon (loaded with alumina) on the upper layer and 13X molecular sieves on the lower layer, forming a double-layer adsorption structure to specifically remove different types of harmful gases and improve the purification effect.

[0139] For example, the adsorption treatment process flow and principle are as follows:

[0140] Gas introduction: The gas, after being neutralized by the tail gas absorption device 300, enters from the bottom air inlet of the adsorption device, flows from bottom to top along the adsorption bed, and comes into full contact with the adsorbent to complete deep purification.

[0141] Adsorption of harmful gases: The upper activated carbon converts residual hydrogen in the gas into harmless water vapor through catalytic oxidation; at the same time, it adsorbs trace amounts of organic impurities and unreacted trace amounts of chlorosilanes; the lower molecular sieve captures residual trace amounts of hydrogen chloride gas with its highly selective adsorption performance, ensuring the complete removal of harmful components.

[0142] Emission Compliance: The gas treated by the double-layer adsorption process meets environmental emission standards for all harmful components and is discharged safely through the exhaust stack from the top outlet of the adsorption unit. A gas detection probe is installed at the outlet to monitor the levels of hydrogen chloride and chlorosilanes in real time. If the detected values ​​exceed the standards, an alarm signal is immediately issued, and the backup adsorption unit is switched on to ensure compliance with emission standards.

[0143] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2 and Figure 3 A flow regulating valve is installed on the pipeline between the vacuum pump 100 and the gas-liquid separation device;

[0144] It also includes: dynamically adjusting the negative pressure intensity entering the gas-liquid separation device through a flow regulating valve based on the flow rate of the chlorosilane mixed medium.

[0145] In this embodiment, an electrically operated corrosion-resistant regulating ball valve is selected for the flow control valve. It is suitable for the highly corrosive and volatile characteristics of chlorosilane mixed media. The valve body is made of Hastelloy alloy, and the valve core is lined with polytetrafluoroethylene. The sealing structure employs a dual design of hard and soft seals to ensure no media leakage under negative pressure and to withstand long-term media corrosion. The valve's rated diameter matches the diameter of the delivery pipeline, and the adjustment accuracy class is no less than Class 1, enabling continuous adjustment from 0-100% opening to meet the requirements of different flow conditions.

[0146] The installation location is selected on a straight pipe section between the outlet of vacuum pump 100 and the inlet of the gas-liquid separator. The distance from the outlet of vacuum pump 100 should be at least 1.5 times the pipe diameter, and the distance from the inlet of the gas-liquid separator should be at least 2 times the pipe diameter. Avoidance of bends, tees, and other disturbing areas is ensured to guarantee stable media flow and provide accurate conditions for flow monitoring and regulation. Valves and pipelines are connected by flanges, and fluororubber gaskets are used for sealing at the interfaces. Bolt tightening torque is uniform to prevent negative pressure leakage.

[0147] A high-precision flow sensor, specifically a Coriolis mass flow meter, is installed on the pipeline between the flow control valve and the gas-liquid separator. This meter is suitable for monitoring the flow of gas-liquid two-phase mixed media, with a measurement range of 5-30 m³ / h and an accuracy class of ±0.2%. It can collect real-time data on the instantaneous and cumulative flow of the chlorosilane mixed media. Simultaneously, pressure transmitters are installed before and after the flow control valve to monitor the pressure difference between the valve's inlet and outlet, providing auxiliary data support for adjusting the negative pressure intensity.

[0148] Both the flow sensor and pressure transmitter are made of corrosion-resistant materials and output a 4-20mA standard electrical signal, which is transmitted to the central control system through a shielded cable. They form a linkage control loop with the flow regulating valve and vacuum pump 100 to achieve closed-loop coordination of flow monitoring, valve regulation, and negative pressure control.

[0149] For example, based on the flow data of the chlorosilane mixed medium collected by the flow sensor, the opening of the flow regulating valve is adjusted by the control system to indirectly adjust the negative pressure intensity entering the gas-liquid separator, adapt to the fluctuation of the medium flow, and maintain the pressure stability inside the gas-liquid separator. The specific process is as follows:

[0150] Initial start-up phase: After starting the vacuum pump 100, adjust the initial opening of the flow regulating valve to 30-50% to establish an initial negative pressure environment (negative pressure intensity in the pipeline: -0.07 to -0.08 MPa). The flow sensor collects the medium flow data in real time and feeds it back to the control system. The control system combines the data from the pressure sensors (first and second pressure sensors) in the gas-liquid separation device to set the initial negative pressure intensity reference value.

[0151] Adjustment logic when flow rate increases: When the flow sensor detects a sudden increase in the flow rate of the chlorosilane mixed medium (such as exceeding the preset value by 15% or more, due to the shedding of silica powder in the filter), the control system automatically increases the opening of the flow regulating valve (each adjustment range is 5-10%) to reduce the flow resistance in the pipeline. At the same time, it finely adjusts the pumping speed of the vacuum pump to moderately increase the negative pressure intensity entering the gas-liquid separation device (the increase range is 5-8%, maintained at -0.085 to -0.095 MPa), ensuring rapid delivery of the medium and avoiding stagnation and accumulation in the pipeline, while matching the processing capacity of the gas-liquid separation device.

[0152] Adjustment logic when flow rate decreases: When the flow sensor detects a decrease in medium flow rate (such as below the preset value by 15% or more, due to partial blockage in the pipeline or the medium delivery is nearing completion), the control system gradually reduces the opening of the flow regulating valve (each adjustment increment is 3-5%), increases the pipeline flow resistance, and correspondingly reduces the negative pressure intensity (down to -0.07 to -0.08 MPa) to avoid the liquid layer inside the gas-liquid separator splashing due to excessive negative pressure, which would affect the gas-liquid separation effect, while also reducing the energy consumption of the vacuum pump by 100%.

[0153] The logic for maintaining stable flow is as follows: When the medium flow rate is maintained within the preset range (fluctuation range ≤ ±5%), the flow regulating valve maintains its current opening. The control system monitors the pressure difference between the valve inlet and outlet and the pressure inside the gas-liquid separator in real time. If there is a slight pressure fluctuation, the negative pressure intensity is corrected by fine-tuning the valve opening (±1-2%) to ensure stable operation of the system.

[0154] See Figure 2 and Figure 3 A chlorosilane recovery and treatment system, comprising:

[0155] A gas-liquid separation device, which is connected to a negative pressure generating device;

[0156] Heat exchanger 200, the input end of heat exchanger 200 is connected to the output end of gas-liquid separator through the first pipe;

[0157] The exhaust gas absorption device 300 has its input end connected to the output end of the heat exchanger 200 via a second pipe.

[0158] This application adopts a modular series architecture, sequentially using a gas-liquid separation device to separate the gas and liquid phases of the medium, a heat exchanger 200 to condense and recover the gaseous chlorosilane medium, and a tail gas absorption device 300 to neutralize the uncondensed gas. Each device is sealed and connected via dedicated corrosion-resistant pipelines, forming a complete closed loop for chlorosilane recovery and treatment. The system is equipped with a negative pressure generating device, monitoring components, and a control system to achieve fully automated operation. It is adaptable to the highly corrosive and volatile characteristics of chlorosilane mixed media, avoiding risks such as leakage and blockage, and meeting the needs of industrial production.

[0159] In this embodiment, the gas-liquid separation device adopts a vertical conical bottom structure. The tower body is made of stainless steel lined with polytetrafluoroethylene, which is resistant to corrosive media such as chlorosilanes and hydrogen chloride. The angle of the conical bottom is set at 60-90° to facilitate the sedimentation of chlorosilane liquid and the collection of silicon powder and high-boiling substances. A liquid outlet is provided at the bottom, a gas outlet is provided at the top, and an air inlet is provided on the side. All are equipped with sealed flange interfaces to ensure no leakage under negative pressure.

[0160] As a pre-processing unit of the system, it mainly realizes the gas-liquid separation of the chlorosilane mixed medium. The negative pressure generated by the negative pressure generating device draws the mixed medium remaining in the filter and pipeline into the device. Utilizing the principle of gravity sedimentation, the denser chlorosilane liquid, silicon powder, and high-boiling substances settle to the bottom of the cone and are transported to the recovery pipeline through the liquid outlet. The gaseous medium, such as hydrogen chloride, hydrogen, and trace amounts of chlorosilane gas, rises to the top and is discharged to the heat exchanger 200 through the gas outlet to provide raw materials for subsequent condensation treatment.

[0161] The device is equipped with a first pressure sensor in the liquid layer area at the bottom and a second pressure sensor in the gas layer area at the top, which monitor the pressure of the liquid and gas phases respectively. The data is transmitted to the control system to provide a basis for negative pressure regulation. A one-way valve is installed at the liquid outlet at the bottom to prevent liquid backflow. At the same time, a liquid level monitor is installed to monitor the amount of liquid settling in real time.

[0162] The gas inlet of the gas-liquid separation device is connected to the negative pressure generating device (vacuum pump 100) through a dedicated pipeline, and a flow regulating valve is installed in the middle of the pipeline to realize dynamic control of the negative pressure intensity; the top gas outlet is connected to the input end of the heat exchanger 200 through the first pipeline to form a directional flow channel for the gas phase medium.

[0163] In this embodiment, the heat exchanger 200 is a two-stage series integrated structure, consisting of a first heat exchanger and a second heat exchanger that are sealed and connected to each other. The first heat exchanger adopts a shell-and-tube structure, with the tube bundle made of Hastelloy alloy. The shell side is used for the flow of cooling medium, and the tube side is used for the flow of gaseous medium. The second heat exchanger adopts a plate structure, with the heat exchange plates made of corrosion-resistant alloy material, resulting in higher heat exchange efficiency and suitability for the condensation requirements of low-concentration gaseous media. The two heat exchangers are connected by corrosion-resistant pipes, and the joints are sealed with fluororubber gaskets to prevent media leakage.

[0164] As the core unit for chlorosilane recovery, it achieves staged condensation and recovery of the gaseous medium. The first heat exchanger uses a first cooling medium (room temperature cooling water) to initially cool the gaseous medium, causing most of the chlorosilane gas to condense into liquid for recovery. The second heat exchanger uses a second cooling medium (low-temperature ethylene glycol solution, with a temperature lower than the first cooling medium) for deep condensation, recovering residual low-concentration chlorosilane gas and maximizing the chlorosilane recovery rate. Uncondensed gas (mainly hydrogen chloride and hydrogen) is discharged to the tail gas absorption device 300.

[0165] Both the first and second heat exchangers are equipped with temperature sensors to monitor the inlet and outlet temperatures of the cooling medium and the gaseous medium. Both the first and second heat exchangers have condensate outlets at the bottom, which are collected and connected to a chlorosilane recovery pipeline to achieve condensate reuse. The outlet of the second heat exchanger is equipped with a pressure monitoring point to provide feedback on the gaseous medium discharge status.

[0166] The input end of heat exchanger 200 is sealed to the gas outlet at the top of the gas-liquid separator through the first pipe to receive the gaseous medium; the output end is connected to the input end of tail gas absorption device 300 through the second pipe to transport uncondensed gas; the cooling medium circulation pipeline is connected to the first and second heat exchangers respectively to form a closed loop circulation of cooling medium.

[0167] In this embodiment, the exhaust gas absorption device 300 adopts a packed tower structure. The tower body is made of stainless steel lined with polytetrafluoroethylene and filled with polypropylene stepped ring packing to increase the gas-liquid contact area. A liquid distributor is provided at the top to ensure uniform spraying of the absorbent liquid. A liquid storage tank is provided at the bottom for storing and circulating alkaline absorbent liquid. A liquid replenishment port and a liquid drain port are provided on the side of the liquid storage tank to realize dynamic replenishment and replacement of absorbent liquid.

[0168] As the final environmental treatment unit of the system, it neutralizes and purifies uncondensed gases. By having an alkaline absorbent solution come into counter-current contact with the uncondensed gases, it neutralizes and removes acidic and harmful components such as hydrogen chloride, while simultaneously reacting to remove trace amounts of residual chlorosilane gases, ensuring that the content of harmful components in the exhaust gas meets environmental emission standards.

[0169] The tower is equipped with an online pH monitor to monitor the pH value of the absorbent in real time and automatically replenish fresh absorbent in conjunction with the replenishment system; a gas flow meter is installed at the air inlet to monitor the flow rate of uncondensed gas; and a gas detection probe is installed at the air outlet to monitor the content of harmful components in the exhaust gas in real time to ensure emission compliance.

[0170] The input end of the exhaust gas absorption device 300 is sealed to the output end of the heat exchanger 200 through a second pipe to receive uncondensed gas; the outlet can be connected to an adsorption device as needed to achieve deep purification of the exhaust gas, and finally discharged in compliance with standards through the exhaust stack; the storage tank is connected to the absorption liquid circulation pump and the replenishment tank to form an absorption liquid circulation and replenishment system.

[0171] 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.

[0172] 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.

[0173] 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).

[0174] 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.

[0175] 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 method for recovering and treating chlorosilanes, characterized in that, include: The chlorosilane mixture is transported to a gas-liquid separator under negative pressure for gas-liquid separation. The gaseous medium separated by the gas-liquid separation device is fed into a heat exchanger for condensation. The uncondensed gas after being condensed by the heat exchanger is fed into the tail gas absorption device for neutralization.

2. The method for recovering and treating chlorosilanes according to claim 1, characterized in that, The chlorosilane mixture is delivered to the gas-liquid separation device via a vacuum pump.

3. The method for recovering and treating chlorosilanes according to claim 2, characterized in that, The step of conveying the chlorosilane mixture to a gas-liquid separator under negative pressure for gas-liquid separation includes: Pressure changes within the gas-liquid separation device are monitored using a pressure sensor. Adjust the pumping rate and / or pressure value of the vacuum pump based on the monitored pressure changes.

4. The method for recovering and treating chlorosilanes according to claim 3, characterized in that, The monitoring of pressure changes within the gas-liquid separation device via a pressure sensor includes: A first pressure sensor and a second pressure sensor are respectively installed in the bottom region and the top region of the gas-liquid separation device; The first pressure sensor is used to detect the pressure of the liquid layer, and the second pressure sensor is used to detect the pressure of the gas layer.

5. The method for recovering and treating chlorosilanes according to any one of claims 1 to 4, characterized in that, The step of inputting the gaseous medium separated by the gas-liquid separation device into a heat exchanger for condensation includes: The heat exchanger includes a first heat exchanger and a second heat exchanger connected in series. The gaseous medium is sequentially introduced into the first heat exchanger and the second heat exchanger; The first heat exchanger performs a first-stage cooling of the gaseous medium using a first cooling medium. The second heat exchanger performs a second-stage condensation of the gaseous medium output from the first heat exchanger using a second cooling medium. The temperature of the second cooling medium is lower than the temperature of the first cooling medium.

6. The method for recovering and treating chlorosilanes according to claim 5, characterized in that, The first cooling medium includes cooling water, and the second cooling medium includes a low-temperature ethylene glycol solution.

7. The method for recovering and treating chlorosilanes according to any one of claims 1 to 4, characterized in that, The step of inputting the uncondensed gas after condensation by the heat exchanger into the tail gas absorption device for neutralization treatment includes: The gas treated by the exhaust gas absorption device is then passed into the adsorption device. The adsorbent in the adsorption device adsorbs harmful gases from the gas after it has been treated by the exhaust gas absorption device.

8. The method for recovering and treating chlorosilanes according to claim 7, characterized in that, The adsorbent includes activated carbon or molecular sieve.

9. The method for recovering and treating chlorosilanes according to any one of claims 2 to 4, characterized in that, A flow regulating valve is provided on the pipeline between the vacuum pump and the gas-liquid separation device; The method further includes: dynamically adjusting the negative pressure intensity entering the gas-liquid separation device through the flow regulating valve according to the flow rate of the chlorosilane mixed medium.

10. A chlorosilane recovery and treatment system, characterized in that, The method for recovering chlorosilanes according to any one of claims 1 to 9 includes: A gas-liquid separation device, wherein the gas-liquid separation device is connected to a negative pressure generating device; A heat exchanger, the input end of which is connected to the output end of the gas-liquid separator via a first pipe; The exhaust gas absorption device has its input end connected to the output end of the heat exchanger via a second pipe.

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