Anti-blocking system and method for polycrystalline silicon cold hydrogenation fluidized bed
By integrating a regulating valve, temperature sensor, and pressure sensor into an anti-clogging system, combined with a DCS control system, real-time monitoring and proactive prevention of polycrystalline silicon cold hydrogenation fluidized bed are achieved, solving the problem of cold hydrogenation fluidized bed clogging and improving the efficiency and safety of the equipment.
Patent Information
- Application Number
- CN202610144695.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-02
- Publication Date
- 2026-04-03
AI Technical Summary
In the polysilicon production process, the blockage problem of cold hydrogenated fluidized beds leads to low equipment efficiency and high safety risks, and existing technologies are unable to achieve real-time monitoring and intelligent prevention.
An anti-clogging system integrating regulating valves, temperature sensors, and pressure sensors is adopted. Real-time diagnosis and precise purging are achieved through the DCS control system. Combined with timed prevention and enhancement modes, it actively prevents silicon powder agglomeration.
Stable operation of the fluidized bed was achieved, reducing unplanned shutdowns and safety risks, improving the plant's operating rate and safety, and reducing energy waste.
Smart Images
Figure CN121775758A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polycrystalline silicon production technology, and in particular to an anti-clogging system and method for a polycrystalline silicon cold hydrogenation fluidized bed. Background Technology
[0002] In the polysilicon production field, the modified Siemens process is the mainstream technology worldwide. In this process, the cold hydrogenation reaction (SiCl4 + H2 + Si → SiHCl3) is a key step in achieving closed-loop material circulation and reducing raw material costs. This reaction takes place in a high-temperature, high-pressure fluidized bed reactor, and its stable operation directly determines the efficiency and cost of the entire polysilicon production line.
[0003] In recent years, as the photovoltaic industry has become increasingly demanding in terms of polysilicon quality and cost, cold hydrogenation units are developing towards larger scale, higher load, and longer operating cycles. However, the expansion of reactor size and the increase in operating intensity have also made internal silicon powder agglomeration, deterioration of fluidization state, and the resulting blockage problems more prominent, becoming a major technical bottleneck restricting the industry's capacity release and stable operation.
[0004] To address the clogging problem in fluidized bed reactors, the industry has explored various technical approaches, including:
[0005] Raw material pretreatment: The incoming silicon powder undergoes deep purification to reduce the content of catalytic metal impurities such as iron, aluminum, and calcium, thereby reducing the melting and adhesion of the silicon powder surface.
[0006] Passive unblocking and maintenance: Pre-install some spare ports or manholes on the reactor shell. When blockage occurs, manually tap or tamp the blockage with tools after shutdown. Alternatively, install simple inert gas (such as nitrogen) bypasses in key parts such as the feed pipeline and purge them when stopping or starting the reactor.
[0007] Although the aforementioned existing technologies have some effect, they all have obvious limitations:
[0008] First, there is an upper limit to the fluctuation in the purity of raw materials, and it is impossible to completely eliminate the initial agglomeration caused by trace impurities or local hot spots.
[0009] Second, when existing monitoring methods (such as temperature and pressure) detect abnormalities, the internal caking has often already developed to a certain extent.
[0010] Third, manual unblocking is the last line of defense, but it can only be carried out after the equipment has been shut down, depressurized, purged, and cooled to safe conditions. The working environment is harsh (toxic and harmful, possibly dusty), and striking operations may damage the equipment itself. It is time-consuming, inefficient, and carries extremely high safety risks.
[0011] Fourth, existing simple purging is usually a manual operation or an operation isolated from the main process, which cannot be intelligently linked with the real-time status of the reactor (such as fluidization quality), and the timing, location and intensity of purging lack scientific basis. Summary of the Invention
[0012] In view of this, the present invention provides an anti-clogging system and method for a polycrystalline silicon cold hydrogenation fluidized bed, the main purpose of which is to provide a way to intelligently handle the blockage and agglomeration of silicon powder in the bed of the cold hydrogenation fluidized bed.
[0013] To achieve the above objectives, the present invention mainly provides the following technical solutions:
[0014] On one hand, the present invention provides an anti-clogging system for a polycrystalline silicon cold hydrogenation fluidized bed, the system comprising: a fluidized bed, a purging section, and a detection section;
[0015] The fluidized bed contains multiple bed layers arranged from top to bottom;
[0016] The purging unit includes a hydrogen main pipe and multiple purging pipes. The hydrogen main pipe is equipped with a regulating valve. One end of each purging pipe is connected to the high-pressure hydrogen main pipe, and the other end penetrates the side wall of the fluidized bed. The purging port on the side wall of the other end of the purging pipe corresponds to one of the bed layers. Each purging pipe is sequentially equipped with a two-position valve and a temperature sensor.
[0017] The detection unit includes an instrument hydrogen tube and multiple detection tubes. One end of each detection tube is connected to the instrument hydrogen tube, and the other end is connected to the purge tube between the temperature sensor and the fluidized bed. Each detection tube is equipped with a pressure sensor.
[0018] The regulating valve, multiple pressure sensors, and multiple two-position valves are integrated into the DCS control system to form an interlocking control mechanism.
[0019] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.
[0020] Optionally, the orientation of the purge port is parallel to the bed.
[0021] Optionally, the curvature of the purge port is 120°.
[0022] Optionally, each of the purge pipes includes a first purge branch pipe and a second purge branch pipe, the first purge branch pipe and the second purge branch pipe being symmetrically distributed on the radially opposite sides of the fluidized bed.
[0023] On the other hand, the present invention provides an anti-clogging method for a polycrystalline silicon cold hydrogenation fluidized bed, using the aforementioned anti-clogging system for a polycrystalline silicon cold hydrogenation fluidized bed, the method comprising the following steps:
[0024] Step 1: The DCS control system activates the timed prevention mode, as detailed below:
[0025] The regulating valve is opened every T1 time interval. At the same time, multiple two-position valves are opened alternately for t1 time intervals to perform basic maintenance on the fluidized bed.
[0026] Step 2: The multiple pressure sensors detect the pressure value of each bed layer and transmit the electrical signal representing the pressure value to the controller. The controller determines whether the electrical signal representing the difference in pressure values between adjacent bed layers is greater than a set value.
[0027] Step 3: When the electrical signal indicating the pressure difference between adjacent beds is less than a set value, the timed prevention mode is maintained; when the electrical signal indicating the pressure difference between adjacent beds is greater than a set value, a bed with a risk of silicon powder agglomeration is identified, and a strengthening mode is activated for that bed, as follows:
[0028] The regulating valve is opened every T2 time period. At the same time, the two-position valve on the purge pipe corresponding to the bed is opened for t2 time, where T1 is greater than T2 and t1 is less than t2.
[0029] Step 4: After two T2 time cycles of the enhanced mode are executed on the bed, the controller again determines whether the electrical signal representing the pressure difference between adjacent beds is greater than the set value. If the electrical signal representing the pressure difference between adjacent beds is less than the set value, the preventive mode is executed on the bed. If the electrical signal representing the pressure difference between adjacent beds is greater than the set value, the controller sends a warning signal to the host computer.
[0030] Optionally, the T1 time is 6 to 8 hours, the T2 time is 2 to 4 hours, the t1 time is 10 to 30 seconds, and the t2 time is 30 to 60 seconds.
[0031] Optionally, in the prevention mode, the opening degree of the regulating valve is 20%, and in the enhancement mode, the opening degree of the regulating valve is 50% to 60%.
[0032] By employing the above technical solution, the present invention has at least the following advantages:
[0033] 1. Shift from passive cleaning to proactive prevention and achieve predictive maintenance: Real-time diagnosis is performed using differential pressure, a parameter that directly reflects fluidization quality, and precise purging intervention is carried out at the initial stage of agglomeration to eliminate problems in their infancy, changing the passive situation of post-event handling.
[0034] 2. Significantly improves the continuous operation cycle of the equipment: effectively inhibits the accumulation and growth of silicon powder, which can avoid or significantly delay unplanned shutdowns caused by severe blockage, and ensure the operating rate and production capacity of the equipment.
[0035] 3. Improve inherent safety level: It greatly reduces the number of times and the necessity for personnel to enter high-risk environments for manual dredging, reduces safety risks such as poisoning, suffocation, and dust explosion, and also avoids physical damage to equipment caused by manual operation.
[0036] 4. High degree of intelligence and automation: The system integrates monitoring, judgment and execution. The operation process does not require frequent manual intervention, which reduces the operational burden. Moreover, the purging action is based on data, avoiding energy waste or excessive bed disturbance caused by blind purging.
[0037] 5. Ensure the integrity of temperature-assisted monitoring hardware to prevent internal leakage and waste of high-pressure hydrogen when it is shut off. Attached Figure Description
[0038] Figure 1 This is a schematic diagram of the anti-clogging system for a polycrystalline silicon cold hydrogenation fluidized bed provided in an embodiment of the present invention;
[0039] Figure 2 for Figure 1 Enlarged view of section A;
[0040] Figure 3 This is a radial cross-sectional view of the fluidized bed.
[0041] The reference numerals in the accompanying drawings include: fluidized bed 1, bed layer 2, hydrogen main pipe 3, purge pipe 4, regulating valve 5, purge port 6, two-position valve 7, temperature sensor 8, instrument hydrogen pipe 9, detection pipe 10, pressure sensor 11, first purge branch pipe 401, and second purge branch pipe 402. Detailed Implementation
[0042] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.
[0043] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.
[0044] On one hand, an embodiment of the present invention provides an anti-clogging system for a polycrystalline silicon cold hydrogenation fluidized bed, which includes: a fluidized bed 1, a purging section and a detection section;
[0045] The fluidized bed 1 has multiple bed layers 2 arranged from top to bottom;
[0046] The purging section includes a hydrogen main pipe 3 and multiple purging pipes 4. The hydrogen main pipe 3 is equipped with a regulating valve 5. One end of each purging pipe 4 is connected to the high-pressure hydrogen main pipe 3, and the other end penetrates the side wall of the fluidized bed 1. The purging port 6 on the side wall of the other end of the purging pipe 4 corresponds to one of the bed layers 2. Each purging pipe 4 is sequentially equipped with a two-position valve 7 and a temperature sensor 8.
[0047] The detection unit includes an instrument hydrogen pipe 9 and multiple detection pipes 10. One end of each detection pipe 10 is connected to the instrument hydrogen pipe 9, and the other end is connected to the purge pipe 4 between the temperature sensor 8 and the fluidized bed 1. Each detection pipe 10 is equipped with a pressure sensor 11.
[0048] The regulating valve 5, the multiple pressure sensors 11, and the multiple two-position valves 7 are integrated into the DCS control system to form an interlocking control mechanism.
[0049] Specifically, the purge pipe 4 is located inside the fluidized bed 1, with its axis perpendicular to the surface of the bed layer 2 of the fluidized bed 1. Two purge ports 6 are arranged sequentially on its pipe wall, with each purge port 6 corresponding to a bed layer 2.
[0050] Specifically, the instrument hydrogen pipe 9 continuously supplies a small flow of hydrogen to the purge pipe 4 through the detection pipe 10, thereby preventing the purge port 6 from being completely blocked, so that the pressure value of the fluidized bed 1 detected by the pressure sensor 11 on the detection pipe 10 tends to be more accurate.
[0051] Specifically, the purpose of installing temperature sensor 8 is as follows: Because the operation of the anti-clogging system of the polycrystalline silicon cold hydrogenation fluidized bed 1 requires precise valve position switching, taking the prevention mode as an example, during the interval of purging the bed layer 2, although the controller sends a closing command to the actuators of multiple two-position valves 7, the valve core of one of the two-position valves 7 is not closed in place. The hydrogen in the hydrogen main pipe 3 (hydrogen at approximately 110°C) will flow through the two-position valve 7, and the detection value of the temperature sensor 8 after the two-position valve 7 will be higher than the detection value of the temperature sensor 8 after the other two-position valves 7. This can promptly detect the situation where the valve core of the two-position valve 7 is not in place or is abnormal, making it easier to detect, replace and repair the two-position valve 7 in a timely manner.
[0052] Specifically, the multiple bed layers 2 of the fluidized bed 1 are a, b, c, d, e, f, g, h, i, j, and k from top to bottom, and the multiple purge pipes 4 are P1, P2, P3, and P4 from bottom to top. It also includes a spare pipe K2 (the connection position of the spare pipe K2 on the side wall of the fluidized bed 1 and the connection position of the silicon powder replenishment pipe K1 on the side wall of the fluidized bed 1 are symmetrical about the central axis of the fluidized bed 1, and the spare pipe K2 is a spare for the silicon powder replenishment pipe K1).
[0053] It also includes a top detection tube 10, which is connected to the upper side of the fluidized bed 1. The top detection tube 10 is also equipped with a pressure sensor 11. The amount of silicon powder material in the space above the bed 2a is determined by the difference between the detection value of the pressure sensor 11 in the top detection tube 10 and the detection value of the pressure sensor 11 in the purge tube P4.
[0054] Specifically, the DN100 hydrogen main pipe 3 is connected to the high-pressure hydrogen pipeline network. The hydrogen main pipe 3 is equipped with a flow meter and a regulating valve 5 in sequence to stably regulate the purging hydrogen pressure to a range 0.4-0.7 MPa higher than the operating pressure in the fluidized bed 1, which is used to control the total hydrogen flow rate.
[0055] In a specific embodiment, the orientation of the purge port 6 is parallel to that of the bed layer 2.
[0056] In this embodiment, specifically, the purge port 6 is oriented parallel to the upper surface of the bed 2, so that the hydrogen gas discharged from the purge port 6 can diffuse along the extension direction of the bed 2 as soon as possible, thereby avoiding the phenomenon of silicon powder agglomeration and blockage on the upper surface of the bed 2 to a certain extent.
[0057] In a specific embodiment, the arc of the purge port 6 is 120°.
[0058] In this embodiment, the plane of the purge port 6 coincides with the radial section of the purge tube 4, and its curvature accounts for one-third of the circumference of the radial section. This allows the hydrogen fluid layer discharged from the purge port 6 to have a wider initial width, which can peel off the silicon powder that tends to agglomerate on the surface of the bed 2 over a larger area in the first time, thus avoiding blockage.
[0059] In a specific embodiment, each of the purge pipes 4 includes a first purge branch pipe 401 and a second purge branch pipe 402, which are symmetrically distributed on the radially opposite sides of the fluidized bed 1.
[0060] In this embodiment, specifically, the purge port 6 of the first purge branch pipe 401 and the purge port 6 of the second purge branch pipe 402 are opposite each other. The blown hydrogen gas flow drives the silicon powder to move towards the middle of the bed 2. With the help of the process gas flowing upward in the fluidized bed 1, the silicon powder and the gas can be better co-fluidized.
[0061] On the other hand, another embodiment of the present invention provides an anti-clogging method for a polycrystalline silicon cold hydrogenation fluidized bed, using the aforementioned anti-clogging system for a polycrystalline silicon cold hydrogenation fluidized bed, the method comprising the following steps:
[0062] Step 1: The DCS control system activates the timed prevention mode, as detailed below:
[0063] Every T1 time interval, the regulating valve 5 is opened, and at the same time, multiple two-position valves 7t1 are opened alternately in sequence to perform basic maintenance on the fluidized bed 1.
[0064] Step 2: The multiple pressure sensors 11 detect the pressure value of each bed layer 2 and transmit the electrical signal representing the pressure value to the controller. The controller determines whether the electrical signal representing the difference in pressure values between adjacent bed layers 2 is greater than a set value.
[0065] Step 3: When the electrical signal indicating the pressure difference between adjacent bed layers 2 is less than a set value, the timed prevention mode is maintained; when the electrical signal indicating the pressure difference between adjacent bed layers 2 is greater than a set value, bed layer 2 with silicon powder agglomeration risk is identified, and the strengthening mode is activated for that bed layer 2, as follows:
[0066] The regulating valve 5 is opened every T2 time period. At the same time, the two-position valve 7 on the purge pipe 4 corresponding to the bed 2 is opened for t2 time, where T1 is greater than T2 and t1 is less than t2.
[0067] Step 4: After two T2 time cycles of the enhanced mode are executed on bed 2, the controller will again determine whether the electrical signal representing the pressure difference between adjacent bed 2 is greater than the set value. If the electrical signal representing the pressure difference between adjacent bed 2 is less than the set value, the preventive mode will be executed on bed 2. If the electrical signal representing the pressure difference between adjacent bed 2 is greater than the set value, the controller will send a warning signal to the host computer.
[0068] Specifically, the setting value is a level value stored in the controller, which represents a pressure value of 50 kPa.
[0069] In a specific implementation, the T1 time is 6 to 8 hours, the T2 time is 2 to 4 hours, the t1 time is 10 to 30 seconds, and the t2 time is 30 to 60 seconds.
[0070] In a specific implementation, in the prevention mode, the opening degree of the regulating valve 5 is 20%, and in the enhancement mode, the opening degree of the regulating valve 5 is 50% to 60%.
[0071] This system and method will link the detection of silicon powder agglomeration location with the switching of hydrogen purging mode, and use the pressure difference distribution of the fluidized bed 1 itself as a signal to drive high-pressure hydrogen purging of agglomeration blockage risk points.
[0072] The anti-clogging system and method for this polycrystalline silicon cold hydrogenation fluidized bed can achieve the following objectives:
[0073] 1. Shift from passive cleaning to proactive prevention and achieve predictive maintenance: Real-time diagnosis is performed using differential pressure, a parameter that directly reflects fluidization quality, and precise purging intervention is carried out at the initial stage of agglomeration to eliminate problems in their infancy, changing the passive situation of post-event handling.
[0074] 2. Significantly improves the continuous operation cycle of the equipment: effectively inhibits the accumulation and growth of silicon powder, which can avoid or significantly delay unplanned shutdowns caused by severe blockage, and ensure the operating rate and production capacity of the equipment.
[0075] 3. Improve inherent safety level: It greatly reduces the number of times and the necessity for personnel to enter high-risk environments for manual dredging, reduces safety risks such as poisoning, suffocation, and dust explosion, and also avoids physical damage to equipment caused by manual operation.
[0076] 4. High degree of intelligence and automation: The system integrates monitoring, judgment and execution. The operation process does not require frequent manual intervention, which reduces the operational burden. Moreover, the purging action is based on data, avoiding energy waste or excessive bed disturbance caused by blind purging.
[0077] 5. Ensure the integrity of temperature-assisted monitoring hardware to prevent internal leakage and waste of high-pressure hydrogen when it is shut off.
[0078] 6. The differential pressure measurement port is also used as a high-pressure hydrogen purging intervention point. This achieves physical and logical unity between monitoring and execution functions.
[0079] 7. By combining time-based periodic prevention with targeted and enhanced intervention based on pressure difference abnormality diagnosis, this composite control strategy ensures comprehensive protection and timely and accurate response.
[0080] 8. Directly use hydrogen, the process gas in the system, to avoid introducing impurities (such as nitrogen) that could contaminate the reaction system, ensuring safety and compatibility.
[0081] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. An anti-clogging system for a polycrystalline silicon cold hydrogenation fluidized bed, characterized in that, include: A fluidized bed, wherein multiple bed layers are arranged from top to bottom within the fluidized bed; The purging section includes a hydrogen main pipe and multiple purging pipes. The hydrogen main pipe is equipped with a regulating valve. One end of each purging pipe is connected to the high-pressure hydrogen main pipe, and the other end penetrates the side wall of the fluidized bed. The purging port on the side wall of the other end of the purging pipe corresponds to one of the bed layers. Each purging pipe is sequentially equipped with a two-position valve and a temperature sensor. The detection unit includes an instrument hydrogen tube and multiple detection tubes. One end of each detection tube is connected to the instrument hydrogen tube, and the other end is connected to the purge tube between the temperature sensor and the fluidized bed. Each detection tube is equipped with a pressure sensor. The regulating valve, multiple pressure sensors, and multiple two-position valves are integrated into the DCS control system to form an interlocking control mechanism.
2. The anti-clogging system for the polycrystalline silicon cold hydrogenated fluidized bed according to claim 1, characterized in that, The orientation of the purge port is parallel to the bed.
3. The anti-clogging system for the polycrystalline silicon cold hydrogenated fluidized bed according to claim 2, characterized in that, The curvature of the purge port is 120°.
4. The anti-clogging system for the polycrystalline silicon cold hydrogenated fluidized bed according to claim 1, characterized in that, Each of the purge pipes includes a first purge branch pipe and a second purge branch pipe, which are symmetrically distributed on opposite radial sides of the fluidized bed.
5. A method for preventing clogging in a polycrystalline silicon cold hydrogenated fluidized bed, characterized in that, The anti-clogging system for the polycrystalline silicon cold hydrogenation fluidized bed according to claim 1 includes the following steps: Step 1: The DCS control system activates the timed prevention mode, as detailed below: The regulating valve is opened every T1 time interval. At the same time, multiple two-position valves are opened alternately for t1 time intervals to perform basic maintenance on the fluidized bed. Step 2: The multiple pressure sensors detect the pressure value of each bed layer and transmit the electrical signal representing the pressure value to the controller. The controller determines whether the electrical signal representing the difference in pressure values between adjacent bed layers is greater than a set value. Step 3: When the electrical signal indicating the pressure difference between adjacent beds is less than a set value, the timed prevention mode is maintained; when the electrical signal indicating the pressure difference between adjacent beds is greater than a set value, a bed with a risk of silicon powder agglomeration is identified, and a strengthening mode is activated for that bed, as follows: The regulating valve is opened every T2 time period. At the same time, the two-position valve on the purge pipe corresponding to the bed is opened for t2 time, where T1 is greater than T2 and t1 is less than t2. Step 4: After two T2 time cycles of the enhanced mode are executed on the bed layer, the controller again determines whether the electrical signal representing the pressure difference between adjacent bed layers is greater than the set value. If the electrical signal representing the pressure difference between adjacent bed layers is less than the set value, the preventive mode is executed on the bed layer. If the electrical signal representing the pressure difference between adjacent bed layers is greater than the set value, the controller sends a warning signal to the host computer.
6. The anti-clogging method for a polycrystalline silicon cold hydrogenated fluidized bed according to claim 5, characterized in that, The T1 time is 6 to 8 hours, the T2 time is 2 to 4 hours, the t1 time is 10 to 30 seconds, and the t2 time is 30 to 60 seconds.
7. The anti-clogging method for a polycrystalline silicon cold hydrogenated fluidized bed according to claim 5, characterized in that, In the prevention mode, the opening degree of the regulating valve is 20%, and in the enhancement mode, the opening degree of the regulating valve is 50% to 60%.