Fluidized bed online ash discharge system suitable for silicon tetrachloride cold hydrogenation device
By designing an online ash removal system for the fluidized bed, the stability problem caused by impurity enrichment in the fluidized bed was solved, and the online continuous discharge of impurities was achieved, ensuring the efficient and stable operation of the cold hydrogenation unit and extending the equipment life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XINJIANG DAQO NEW ENERGY CO LTD
- Filing Date
- 2026-03-16
- Publication Date
- 2026-05-05
AI Technical Summary
In polysilicon production, the accumulation of impurities in the fluidized bed of the cold hydrogenation unit leads to bed instability, affecting the stable operation of the unit. Furthermore, existing methods, such as adjusting process parameters or shutting down for ash removal, are complex, inefficient, and costly.
Design an online ash removal system for a silicon tetrachloride cold hydrogenation unit, including fluidized bed equipment, ash collection tank, filter and ash discharge tank. Through the combination of pipelines and valves, online continuous discharge of impurities is achieved, maintaining fluidization quality and reaction efficiency.
This enables continuous online discharge of impurities from the fluidized bed, ensuring efficient and stable operation of the cold hydrogenation unit, reducing unplanned downtime, lowering production costs, and extending equipment operating cycles.
Smart Images
Figure CN121972097A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polycrystalline silicon production technology, and in particular to a fluidized bed online ash removal system suitable for a silicon tetrachloride cold hydrogenation unit. Background Technology
[0002] In polysilicon production, cold hydrogenation technology is a key step in improving the Siemens process. Its core is the conversion of silicon tetrachloride (SiCl4) to trichlorosilane (SiHCl3) through a gas-solid heterogeneous reaction. This reaction is typically carried out under high temperature and pressure conditions, using metallurgical-grade silicon powder and copper-based catalysts to ensure high conversion efficiency. However, during long-term operation of the cold hydrogenation unit, impurities (such as Fe, Al, and Ca) gradually accumulate in the fluidized bed, leading to bed instability and becoming a bottleneck affecting the stable operation of the unit. The accumulation of impurities causes the following problems:
[0003] 1. Product contamination: Impurity particles can easily enter the chlorosilane product system, increasing the burden of subsequent purification, potentially clogging equipment, and affecting the normal operation of the unit; 2. Decreased conversion efficiency: Impurities cover the active sites of the catalyst, leading to a decrease in the SiCl4 conversion rate, affecting the yield of trichlorosilane, and increasing energy consumption; 3. Unplanned shutdowns: Frequent shutdowns for maintenance are required to remove impurities, affecting the operating efficiency of the unit and causing economic losses.
[0004] Currently, the industry mainly addresses impurity issues by adjusting process parameters or shutting down the plant to remove ash, but these methods are characterized by complex operation, low efficiency, and high cost. Summary of the Invention
[0005] In view of this, the present invention provides an online ash removal system for a fluidized bed suitable for a silicon tetrachloride cold hydrogenation device. The main purpose is to achieve continuous online discharge of impurities from the fluidized bed without interfering with the fluidization quality or affecting the reaction efficiency, thereby ensuring the efficient and stable operation of the cold hydrogenation device.
[0006] To achieve the above objectives, the present invention mainly provides the following technical solutions:
[0007] Embodiments of the present invention provide a fluidized bed online ash removal system suitable for a silicon tetrachloride cold hydrogenation unit, comprising: fluidized bed equipment, ash collection tank, filter, and ash removal tank;
[0008] The fluidized bed equipment is provided with a discharge port at the bottom;
[0009] The inlet of the ash collection hopper is connected to the outlet through a pipeline; an ash collection valve is installed on the pipeline.
[0010] The top of the ash collection tank is provided with a uniform pressure inlet and a pressure relief outlet; the uniform pressure inlet is connected to the fluidized bed equipment through a second pipeline; a uniform pressure valve is provided on the second pipeline; and a hydrogen inlet is provided on the ash collection tank.
[0011] The filter is connected to the pressure relief port of the ash collection tank via pipeline three; a pressure relief regulating valve is installed on pipeline three.
[0012] The filter is equipped with a hydrogen backflush port;
[0013] The filter is equipped with a pressure relief pipeline for connecting to the regenerated hydrogen pipeline network; the pressure relief pipeline is equipped with a filter pressure relief valve.
[0014] The inlet of the ash discharge tank is connected to the outlet of the ash collection tank through pipe four; an ash collection and discharge valve is installed on pipe four.
[0015] The pressure relief port of the ash discharge tank is connected to the ash collection tank through pipeline five; an ash discharge pressure relief valve is installed on pipeline five.
[0016] The hydrogen inlet of the ash discharge tank is connected to the discharge port of the filter through pipeline six; a filter discharge valve is installed on pipeline six.
[0017] The ash discharge tank is equipped with a hydrogen replacement pipeline;
[0018] The ash discharge tank is equipped with a nitrogen purging inlet; the ash discharge tank is equipped with a nitrogen purging outlet.
[0019] The bottom of the ash discharge tank is provided with an ash discharge port; the ash discharge port is provided with an ash discharge valve.
[0020] Furthermore, it also includes: an ash discharge screw conveyor;
[0021] The ash discharge screw conveyor is connected to the ash discharge port through pipeline seven.
[0022] Furthermore, the filter is equipped with a ceramic filter element.
[0023] Furthermore, there are two ash collection valves; the two ash collection valves are connected in series on the first pipeline.
[0024] Furthermore, there are two equalizing valves; the two equalizing valves are connected in series on the second pipeline.
[0025] Furthermore, there are two pressure relief regulating valves; the two pressure relief regulating valves are connected in series on the pipeline.
[0026] Furthermore, there are two ash collection and discharge valves; the two ash collection and discharge valves are connected in series on the pipeline.
[0027] Furthermore, there are two ash discharge and pressure relief valves; the two ash discharge and pressure relief valves are connected in series on the pipeline.
[0028] By employing the above technical solution, the fluidized bed online ash removal system of the silicon tetrachloride cold hydrogenation unit of the present invention has at least the following advantages:
[0029] It enables continuous online discharge of impurities from the fluidized bed without interfering with fluidization quality or affecting reaction efficiency, ensuring efficient and stable operation of the cold hydrogenation unit.
[0030] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description
[0031] Figure 1 This is a schematic diagram of an online ash removal system for a silicon tetrachloride cold hydrogenation device, provided as an embodiment of the present invention.
[0032] As shown in the figure:
[0033] 1 is the fluidized bed equipment; 1-1 is the discharge port; 2 is the ash collection tank; 2-1 is the hydrogen inlet; 3 is the ash discharge tank; 3-1 is the nitrogen replacement inlet; 3-2 is the hydrogen replacement pipeline; 4 is the filter; 4-1 is the hydrogen backflush port; 5 is pipeline one; 6 is pipeline two; 7 is pipeline three; 8 is pipeline five; 9 is pipeline four; 10 is pipeline six; 11 is the pressure relief pipeline; 12 is the ash discharge screw conveyor; 13 is the nitrogen replacement outlet. Detailed Implementation
[0034] 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.
[0035] like Figure 1 As shown, an embodiment of the present invention proposes a fluidized bed online ash removal system suitable for a silicon tetrachloride cold hydrogenation device, comprising: a fluidized bed device 1, an ash collection tank 2, a filter 4, and an ash discharge tank 3; the lower part of the fluidized bed device 1 is provided with a discharge port 1-1 for discharging impurities; the inlet of the ash collection tank 2 is connected to the discharge port 1-1 through a pipeline 5 for receiving impurities discharged from the fluidized bed device 1; an ash collection valve is provided on the pipeline 5 for controlling the opening and closing of the pipeline 5; furthermore, there are two ash collection valves; the two ash collection valves are connected in series on the pipeline 5 to ensure the reliability of the control of the pipeline 5.
[0036] The top of the ash collection tank 2 is equipped with a pressure equalization port and a pressure relief port. The pressure equalization port is connected to the fluidized bed equipment 1 via pipeline 2 6, which balances the pressure between the ash collection tank 2 and the fluidized bed equipment 1, reducing wear on pipeline 1 5 and the ash collection valve during discharge. It also reduces interference with the normal operation of the fluidized bed equipment 1 during ash collection. A pressure equalization valve is installed on pipeline 2 6 to control its on / off state; preferably, two pressure equalization valves are connected in series on pipeline 2 6 to ensure reliable control of pipeline 2 6. The ash collection tank 2 is equipped with a hydrogen inlet 2-1 for filling the ash collection tank 2 with hydrogen.
[0037] The filter 4 is connected to the pressure relief port of the ash collection tank 2 via pipe 3 7; preferably, the filter 4 is equipped with a ceramic filter element.
[0038] A pressure relief regulating valve is installed on pipeline 3 7; preferably, there are two pressure relief regulating valves; the two pressure relief regulating valves are connected in series on pipeline 3 7 to ensure the reliability of the control of pipeline 3 7.
[0039] The filter 4 is equipped with a hydrogen backflush port 4-1 for introducing hydrogen into the filter 4 and simultaneously backflush cleaning the filter element; the filter 4 is equipped with a pressure relief pipeline 11 for connecting to the regenerated hydrogen pipeline network to achieve hydrogen recycling; the pressure relief pipeline 11 is equipped with a filter pressure relief valve for controlling the opening and closing of the pressure relief pipeline 11; by using the filter 4 to recycle and reuse hydrogen during the pressure charging and depressurization process, hydrogen consumption can be reduced and production costs can be lowered.
[0040] The inlet of the ash discharge tank 3 is connected to the outlet of the ash collection tank 2 through pipe 4 9 to receive the impurities output from the ash collection tank 2; an ash collection discharge valve is provided on pipe 4 9 to control the opening and closing of pipe 4 9; preferably, there are two ash collection discharge valves; the two ash collection discharge valves are connected in series on pipe 4 9 to ensure the reliability of the control of pipe 4 9.
[0041] The pressure relief port of the ash discharge tank 3 is connected to the ash collection tank 2 through pipeline 5 8 to balance the pressure of the ash discharge tank 3 and the ash collection tank 2, ensure the stability of material discharge, and reduce damage to pipeline 4 9 and the ash collection discharge valve. An ash discharge pressure relief valve is installed on pipeline 5 8 to control the opening and closing of pipeline 5 8. Preferably, there are two ash discharge pressure relief valves. The two ash discharge pressure relief valves are connected in series on pipeline 5 8 to ensure the reliability of the control of pipeline 5 8.
[0042] The hydrogen inlet of the ash discharge tank 3 is connected to the discharge port of the filter 4 through pipeline 6 10; a filter discharge valve is installed on pipeline 6 10 to control the opening and closing of pipeline 6 10.
[0043] The ash discharge tank 3 is equipped with a hydrogen replacement pipeline 3-2 for outputting the replaced hydrogen.
[0044] The ash discharge tank 3 is equipped with a nitrogen replacement inlet 3-1 for inputting nitrogen; the ash discharge tank 3 is equipped with a nitrogen replacement outlet 13 for outputting the replaced material.
[0045] The bottom of the ash discharge tank 3 is provided with an ash discharge port for discharging the material inside the ash discharge tank 3; an ash discharge valve is provided on the ash discharge port for controlling the opening and closing of the ash discharge port.
[0046] One embodiment of the present invention proposes a fluidized bed online ash removal system suitable for a silicon tetrachloride cold hydrogenation unit. Taking advantage of the small particle size of impurities, the system forms a fluidized state for transport within the container, enabling continuous online discharge of impurities from the fluidized bed without interfering with the fluidization quality or affecting the reaction efficiency. This system can be reused repeatedly, saving slag removal costs.
[0047] An embodiment of the present invention proposes an online ash removal system for a fluidized bed in a silicon tetrachloride cold hydrogenation unit. By repeatedly pressurizing and depressurizing the ash collection tank 2, impurities in the fluidized bed equipment are collected, maintaining the reactivity of silicon powder in the fluidized bed equipment, reducing unplanned shutdowns, ensuring efficient and stable operation of the cold hydrogenation unit, and extending the operating cycle of the cold hydrogenation fluidized bed equipment 1.
[0048] An embodiment of the present invention provides a fluidized bed online ash removal system suitable for a silicon tetrachloride cold hydrogenation unit, which can collect ash residue in a resource-efficient manner, facilitating subsequent resource utilization of the ash residue.
[0049] As a preferred embodiment of the above embodiments, one embodiment of the present invention provides a fluidized bed online ash removal system suitable for a silicon tetrachloride cold hydrogenation device, which further includes: an ash removal screw conveyor 12; the ash removal screw conveyor 12 is connected to the ash discharge port through a pipeline 7.
[0050] An embodiment of the present invention provides a fluidized bed online ash removal system suitable for a silicon tetrachloride cold hydrogenation unit. The main ash removal process is as follows: pressurization → ash collection → pressure relief → ash removal → replacement discharge.
[0051] Pressurization: High-pressure hydrogen is introduced into the ash collection tank 2 through the hydrogen inlet 2-1 to maintain the pressure of the ash collection tank 2 and the fluidized bed equipment 1. Then, the hydrogen inlet 2-1 is closed and the pressure equalization valve of the ash collection tank 2 is opened to make the pressure of the ash collection tank 2 and the fluidized bed equipment 1 connected, which reduces the wear on the pipeline and valves during material discharge and also reduces the interference to the fluidized bed during the ash collection process.
[0052] Ash collection: After the ash collection tank 2 is connected to the air connection of the fluidized bed equipment 1, the ash collection valve is opened to carry out the ash collection operation. After the predetermined ash collection amount is reached, the ash collection valve is closed; then the pressure equalization valve of the ash collection tank 2 is closed to complete the ash collection.
[0053] Pressure Relief: After ash collection is complete, keep the pressure relief valve of filter 4 open, open the pressure relief regulating valve of ash collection tank 2, and slowly depressurize ash collection tank 2 through the pressure relief regulating valve. The depressurized gas containing ash is filtered through filter 4 and then transported to the regenerated hydrogen system for recycling through pressure relief pipeline 11. After the pressure is reduced to atmospheric pressure, close the pressure relief regulating valve of ash collection tank 2.
[0054] Ash Discharge: Close the ash discharge valve of ash discharge tank 3, open the ash discharge pressure relief valve of ash discharge tank 3 to equalize the pressure between ash collection tank 2 and ash discharge tank 3, then open the ash collection discharge valve of ash collection tank 2 to discharge the ash into ash discharge tank 3. Close the ash discharge pressure relief valve of ash discharge tank 3 and the ash collection discharge valve of ash collection tank 2. Ash collection tank 2 can continue the pressurization and ash collection process.
[0055] Replacement Discharge: Open the filter discharge valve and filter pressure relief valve of filter 4, and the hydrogen replacement pipeline 3-2 to replace the ash residue in the ash discharge tank 3, removing the chlorosilanes from the ash residue. After replacement, close the above valves and open the nitrogen replacement outlet 13 to release pressure to the nitrogen-containing waste gas system. After the hydrogen in the ash discharge tank 3 is completely replaced by nitrogen, start the ash discharge screw conveyor 12 and open the ash discharge valve of the ash discharge tank 3 to discharge the ash residue.
[0056] Method for handling filter 4 blockage: Close the filter pressure relief valve of filter 4, open the filter discharge valve and hydrogen backflush port 4-1 of filter 4, and discharge the ash and slag in filter 4 to the ash discharge tank 3.
[0057] To further clarify, while the terms "first," "second," etc., may be used herein to describe various elements, these terms should not limit the elements. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element; these terms are used only to distinguish one element from another. This does not depart from the scope of the exemplary embodiments. Similarly, "element one," "element two," and so on do not represent the order of elements; these terms are used only to distinguish one element from another. As used herein, the term "and / or" includes any and all combinations of one or more associated listed items.
[0058] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0059] All standard parts used in this invention can be purchased from the market, and irregular parts can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment adopt conventional models in the prior art, and the circuit connection adopts conventional connection methods in the prior art, which will not be described in detail here.
[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.
Claims
1. A fluidized bed online ash removal system suitable for a silicon tetrachloride cold hydrogenation unit, characterized in that, Includes: fluidized bed equipment, ash collection hopper, filter, and ash discharge hopper; The fluidized bed equipment is provided with a discharge port at the bottom; The inlet of the ash collection hopper is connected to the outlet through a pipeline; an ash collection valve is installed on the pipeline. The top of the ash collection tank is provided with a uniform pressure inlet and a pressure relief outlet; the uniform pressure inlet is connected to the fluidized bed equipment through a second pipeline; a uniform pressure valve is provided on the second pipeline; and a hydrogen inlet is provided on the ash collection tank. The filter is connected to the pressure relief port of the ash collection tank via pipeline three; a pressure relief regulating valve is installed on pipeline three. The filter is equipped with a hydrogen backflush port; The filter is equipped with a pressure relief pipeline for connecting to the regenerated hydrogen pipeline network; the pressure relief pipeline is equipped with a filter pressure relief valve. The inlet of the ash discharge tank is connected to the outlet of the ash collection tank through pipe four; an ash collection and discharge valve is installed on pipe four. The pressure relief port of the ash discharge tank is connected to the ash collection tank through pipeline five; an ash discharge pressure relief valve is installed on pipeline five. The hydrogen inlet of the ash discharge tank is connected to the discharge port of the filter through pipeline six; a filter discharge valve is installed on pipeline six. The ash discharge tank is equipped with a hydrogen replacement pipeline; The ash discharge tank is equipped with a nitrogen purging inlet; the ash discharge tank is equipped with a nitrogen purging outlet. The bottom of the ash discharge tank is provided with an ash discharge port; the ash discharge port is provided with an ash discharge valve.
2. The fluidized bed online ash removal system for a silicon tetrachloride cold hydrogenation unit according to claim 1, characterized in that, Also includes: Ash removal screw conveyor; The ash discharge screw conveyor is connected to the ash discharge port through pipeline seven.
3. The fluidized bed online ash removal system for a silicon tetrachloride cold hydrogenation unit according to claim 1, characterized in that, The filter contains a ceramic filter element.
4. The fluidized bed online ash removal system for a silicon tetrachloride cold hydrogenation unit according to claim 1, characterized in that, There are two ash collection valves; the two ash collection valves are connected in series on the pipeline.
5. The fluidized bed online ash removal system for a silicon tetrachloride cold hydrogenation unit according to claim 1, characterized in that, There are two pressure equalization valves; the two pressure equalization valves are connected in series on the second pipeline.
6. The fluidized bed online ash removal system for a silicon tetrachloride cold hydrogenation unit according to claim 1, characterized in that, There are two pressure relief regulating valves; the two pressure relief regulating valves are connected in series on the pipeline.
7. The fluidized bed online ash removal system for a silicon tetrachloride cold hydrogenation unit according to claim 1, characterized in that, There are two ash collection and discharge valves; the two ash collection and discharge valves are connected in series on the pipeline.
8. The fluidized bed online ash removal system for a silicon tetrachloride cold hydrogenation unit according to claim 1, characterized in that, There are two ash discharge and pressure relief valves; the two ash discharge and pressure relief valves are connected in series on the pipeline.