A steam regulating valve assembly for a polycrystalline silicon differential pressure coupled distillation column

Abstract

This application discloses a steam regulating valve assembly for a polycrystalline silicon differential pressure coupled distillation column. The steam regulating valve assembly is installed on the steam pipeline to regulate the amount of steam entering the reboiler. The steam regulating valve assembly includes: a main regulating valve unit, which is installed on the steam pipeline and has a first through-hole, and is used to regulate the flow rate of the main steam during the stable operation phase of the distillation column; and an auxiliary regulating valve unit, which is also installed on the steam pipeline and has a second through-hole, which is smaller than the first through-hole, and is used to perform micro-flow control of steam during the start-up phase of the distillation column.

Description

Technical Field

[0001] This application relates to the field of polysilicon production equipment technology, and more specifically to a steam regulating valve assembly for a polysilicon differential pressure coupled distillation column. Background Technology

[0002] Currently, the purification of trichlorosilane in polycrystalline silicon distillation workshops using the modified Siemens process typically employs a multi-tower differential pressure coupling operation mode. As the scale of the plant increases and the throughput grows, the steam regulating valves of the distillation towers heated by the heat source steam are selected from two or more valves in a group, taking into account factors such as overall cost and actual valve selection, to simultaneously control the steam flow and the start-up and adjustment operations of the distillation towers.

[0003] In existing technologies, when steam regulating valve groups are used in sets of two or more, the valve diameter is reduced. For example, in a three-tower coupling of a distillation workshop's hydrogenation feed purification tower, the main steam line diameter of a single reboiler is DN900, but when two steam regulators are used, the valve diameter is still DN500. Therefore, the following problems are still unavoidable: the regulating valve group diameter is too large, making selection difficult. At the same time, it is difficult to achieve relatively precise control during normal operation of the distillation tower. Because the steam regulating valve diameter is large, the sensitivity cannot meet the requirements for relatively precise control, making it difficult to implement automated control. Or, after the implementation of automated control, the control parameters of the distillation tower are not stable enough, affecting product quality. Furthermore, the regulating sensitivity of large-diameter steam regulating valves is reduced at small openings, which is not conducive to controlling the temperature rise rate during the initial start-up of the distillation tower. Utility Model Content

[0004] The purpose of this application is to provide a steam regulating valve assembly for a polycrystalline silicon differential pressure coupled distillation column, so as to optimize the control stability of the distillation column in accordance with actual production control requirements.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: A steam regulating valve assembly for a polycrystalline silicon differential pressure coupled distillation column is provided. The steam regulating valve assembly is installed on a steam pipeline to regulate the amount of steam entering the reboiler. The steam regulating valve assembly includes: a main regulating valve unit, which is installed on the steam pipeline and has a first through-hole, used to regulate the flow rate of the main steam during the stable operation phase of the distillation column; and an auxiliary regulating valve unit, which is installed on the steam pipeline and has a second through-hole smaller than the first through-hole, used for micro-flow control of steam during the start-up phase of the distillation column.

[0006] As a preferred embodiment, the sum of the first diameter of the main regulating valve unit and the second diameter of the auxiliary regulating valve unit is adapted to the maximum design flow rate of the steam pipeline.

[0007] As another preferred embodiment, the main regulating valve unit and the auxiliary regulating valve unit are connected in parallel on the steam pipeline; wherein, during the stable operation phase of the distillation column, the auxiliary regulating valve unit works in conjunction with the main regulating valve unit to compensate for fluctuations in steam flow.

[0008] More preferably, the second port diameter of the auxiliary regulating valve unit does not exceed half of the first port diameter of the main regulating valve unit.

[0009] Further preferably, the main regulating valve unit also includes multiple regulating valves, which are connected in parallel with the auxiliary regulating valve unit on the steam pipeline.

[0010] Preferably, the main regulating valve unit further includes a first regulating valve and a second regulating valve, and the auxiliary regulating valve unit, the first regulating valve and the second regulating valve are arranged in parallel on the steam pipeline.

[0011] Preferably, the first regulating valve has a third through diameter, the second regulating valve has a fourth through diameter, and the first through diameter is the sum of the third through diameter and the fourth through diameter; wherein, the third through diameter of the first regulating valve is larger than the second through diameter of the auxiliary regulating valve.

[0012] Preferably, the fourth diameter of the second regulating valve is larger than the second diameter of the auxiliary regulating valve.

[0013] Further preferably, the first diameter of the main regulating valve unit reaches 75%-95% of the diameter of the steam pipeline.

[0014] Compared with the prior art, the beneficial effects of this application are as follows:

[0015] By employing a dynamic division of labor between the large-diameter main regulating valve unit and the small-diameter auxiliary regulating valve unit, a differentiated flow control system is constructed throughout the complete operating cycle of the distillation column. Specifically, during the start-up phase, the auxiliary regulating valve unit, with its small-diameter characteristics, achieves high sensitivity and precision in controlling the distillation column's heating rate under low steam flow conditions. This avoids temperature overshoot or large fluctuations in the distillation column caused by excessive adjustment from the large-diameter main regulating valve unit, effectively shortening the time window for the system to reach steady state. During the steady-state operation phase, the main regulating valve unit, leveraging its diameter advantage, bears the basic load. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a polycrystalline silicon differential pressure coupled distillation column;

[0017] Figure 2 This is a structural diagram showing the location of the steam regulating valve in the relevant technology;

[0018] Figure 3 for Figure 1 A magnified view of the steam regulating component at point A in the middle;

[0019] Figure 4 This is a schematic diagram of the steam conditioning assembly in some embodiments.

[0020] In the diagram: 100, Polycrystalline silicon differential pressure coupled distillation column; 1, Steam regulating valve assembly; 2, Distillation column; 3, Reboiler; 4, Steam line; 5, Cooler; 6, Reflux pump; 7, Reflux tank; 8, First steam regulating valve; 9, Second steam regulating valve; 10, Main regulating valve unit; 11, First regulating valve; 12, Second regulating valve; 20, Auxiliary regulating valve unit. Detailed Implementation

[0021] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0022] In the description of this application, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this application.

[0023] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0024] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0025] In a preferred embodiment, see Figure 1 , Figure 3 and Figure 4This application provides a steam regulating valve assembly 1 for a polycrystalline silicon differential pressure coupled distillation column 100. The steam regulating valve assembly 1 is installed on the steam line 4 to regulate the amount of steam entering the reboiler 3. The steam regulating valve assembly 1 includes: a main regulating valve unit 10, which is installed on the steam line 4 and has a first through-hole. The main regulating valve unit 10 is used to regulate the flow rate of the main steam during the stable operation phase of the distillation column 2; and an auxiliary regulating valve unit 20, which is also installed on the steam line 4 and has a second through-hole smaller than the first through-hole. The auxiliary regulating valve unit 20 is used to perform micro-flow control of steam during the start-up phase of the distillation column 2.

[0026] In this process, the reboiler 3 serves as the heat source for the distillation column 2, primarily responsible for providing continuous heat to the column, causing partial vaporization of the liquid in the reboiler and forming an upward steam flow. Therefore, the reboiler 3 is needed to maintain the vaporization process within the distillation column 2. This requires heating the liquid in the reboiler, such as a mixture of trichlorosilane and other components, to its boiling point, causing partial vaporization and generating steam. This steam rises from the bottom to the top of the column, contacting the downstream liquid in a counter-current manner to achieve component separation. Simultaneously, the energy consumed by the reboiler 3 accounts for a significant proportion of the overall distillation system's energy consumption, directly impacting process economics. Therefore, in the differential pressure coupling process described in this application, external steam reaches the reboiler 3 via the steam regulating valve assembly 1.

[0027] Therefore, the polycrystalline silicon differential pressure coupled distillation column 100 in this application is also equipped with a control module to control the opening and closing degree of the valve port of the steam regulating valve assembly 1, thereby controlling the steam flow rate of the external steam source entering the reboiler 3 through the steam pipeline 4. The core function of the steam regulating valve assembly 1 in this application is to regulate the amount of steam entering the reboiler 3, thereby controlling the heating intensity of the distillation column 2 bottom, thereby stabilizing the heat balance and separation efficiency of the distillation column 2.

[0028] This application document optimizes equipment selection economy, control precision, and process stability through the hierarchical synergistic effect of the main regulating valve unit 10 and the auxiliary regulating valve unit 20. In practical applications, a differentiated flow control system is constructed throughout the complete operating cycle of the distillation column 2 by employing a dynamic division of labor mechanism between the large-diameter main regulating valve unit 10 and the small-diameter auxiliary regulating valve unit 20. Specifically, during the start-up phase of the distillation column 2, the auxiliary regulating valve unit 20, with its small-diameter characteristics, achieves high sensitivity and precision in controlling the heating rate of the distillation column 2 under low steam flow conditions. This avoids temperature overshoot or large fluctuations in the distillation column 2 caused by excessive adjustment of the large-diameter main regulating valve unit 10, effectively shortening the time window for the system to reach steady state. When the distillation column 2 is in steady-state operation, the main regulating valve unit 10, relying on its diameter advantage, bears the basic load.

[0029] That is, in some embodiments, during the start-up phase of the distillation column 2, the main regulating valve unit 10 is closed by the control module and the steam flow is fully regulated by the auxiliary regulating valve unit 20; during the stabilization phase of the distillation column 2, the main regulating valve unit 10 is activated by the control module to undertake the basic flow regulation.

[0030] Preferably, the main regulating valve unit 10 and the auxiliary regulating valve unit 20 are connected in parallel on the steam pipeline 4, so that the main regulating valve unit 10 and the auxiliary regulating valve unit 20 are independent of each other and their valve opening adjustments do not interfere with each other. During the stable operation of the distillation column 2, the auxiliary regulating valve unit 20 works in conjunction with the main regulating valve unit 10 to compensate for steam flow fluctuations. Specifically, the auxiliary regulating valve unit 20 acts as a fine-tuning unit to compensate for the flow control deviation generated by the main regulating valve unit 10 in real time. That is, the auxiliary regulating valve unit 20 is used in this application for auxiliary temperature rise regulation during the start-up of the distillation column 2 and fine auxiliary stabilization control after the system is in stable operation. At the same time, the auxiliary regulating valve unit 20 performs high-frequency fine-tuning to maintain the set process parameters of the reboiler 3.

[0031] In addition, since the auxiliary regulating valve unit 20 only undertakes intermittent fine-tuning tasks, its fatigue wear is lower than that of valve groups of the same diameter that operate frequently in related technologies, effectively reducing the subsequent replacement frequency of the auxiliary regulating valve unit 20.

[0032] As a preferred option, the sum of the first diameter of the main regulating valve unit 10 and the second diameter of the auxiliary regulating valve unit 20 is adapted to the maximum design flow of the steam pipeline 4. By precisely matching the design limit flow of the steam pipeline 4, the full load coverage capability of the steam supply under extreme operating conditions is ensured, and the efficient regulation capability under high flow is fully utilized through the coordinated division of labor between the main regulating valve unit 10 and the auxiliary regulating valve unit 20.

[0033] Further preferably, the second port diameter of the auxiliary regulating valve unit 20 does not exceed half of the first port diameter of the main regulating valve unit 10. The main regulating valve unit 10 has a larger first port diameter, enabling it to handle the steam flow load at the main flow rate within a higher opening range. In contrast, the second port diameter of the auxiliary regulating valve unit 20 is limited and less than half of the first port diameter. Consequently, the maximum flow rate of the auxiliary regulating valve unit 20 is anchored within the system disturbance compensation range, typically between 15% and 25% of the total flow rate, and its operating time is less than that of the main regulating valve unit 10. Therefore, the mechanical wear rate of the auxiliary regulating valve unit 20 is lower.

[0034] Furthermore, the main regulating valve unit 10 also includes multiple regulating valves, which are connected in parallel with the auxiliary regulating valve unit 20 on the steam pipeline 4. Preferably, the multiple regulating valves in this application are specifically configured as two, that is, the main regulating valve unit 10 also includes a first regulating valve 11 and a second regulating valve 12, and the auxiliary regulating valve unit 20, the first regulating valve 11 and the second regulating valve 12 are connected in parallel on the steam pipeline 4.

[0035] Preferably, the first regulating valve 11 has a third through diameter, and the second regulating valve 12 has a fourth through diameter, and the first through diameter is the sum of the third through diameter and the fourth through diameter; wherein, the third through diameter of the first regulating valve 11 is larger than the second through diameter of the auxiliary regulating valve, and the fourth through diameter of the second regulating valve 12 is larger than the second through diameter of the auxiliary regulating valve.

[0036] Therefore, specifically, in one particular implementation, depending on different design conditions, operating conditions, and the varying regulating performance of the manufacturer's supplied regulating valves, the required control requirements can be achieved by adding two regulating valve ports. The added regulating valve ports are the first regulating valve 11 and the second regulating valve 12. See details... Figures 1 to 3 ,in Figure 2 This illustrates the configuration of the first steam regulating valve 8 and the second steam regulating valve 9 in related technologies. In this embodiment, the steam pipeline 4 is preferably DN900. However, because the diameter of the steam pipeline 4 is too large, the required diameter of the regulating valves is also too large. Related technologies would use a first steam regulating valve 8 with a diameter of DN500 and a second steam regulating valve 9 with a diameter of DN500 as two regulating valves connected in parallel. However, because the diameter of the regulating valve ports is also too large, it will lead to insufficient regulating accuracy. Therefore, see [link to relevant documentation]. Figure 3 In this application, a first regulating valve 11 and a second regulating valve 12 are set as the main regulating valve unit 10, while an auxiliary regulating valve unit 20 is used in conjunction. The third port diameter of the first regulating valve 11 can be set to DN450, the fourth port diameter of the second regulating valve 12 can be set to DN400, and the second port diameter of the auxiliary regulating valve unit 20 is DN250. This allows for auxiliary temperature regulation during the start-up of the distillation column 2 and fine and stable control during normal operation. The first regulating valve 11 and the second regulating valve 12 are used to regulate the main steam flow after the distillation column 2 is running stably.

[0037] Furthermore, in another specific implementation, see [link to relevant documentation]. Figure 4Depending on different design conditions, operating conditions, and the varying performance of the control valves supplied by the manufacturer, the required control requirements can be achieved by adjusting the diameters of the two control valves. Specifically, in this embodiment, the diameter of the steam pipeline 4 can be set to DN400. In this case, the two steam control valves of the same diameter in the related technology are set to two DN250 control valve ports, which cannot meet the stable control of the distillation column 2 under this operating condition. Therefore, according to the scheme provided in this application, a main control valve unit 10 is set. The first diameter of the main control valve is set to DN300, which serves as the main steam flow regulation valve after the distillation column 2 is running stably. At the same time, an auxiliary control valve unit 20 is set. The second diameter of the auxiliary control valve unit 20 is set to DN150. The DN150 auxiliary control valve unit 20 is used for auxiliary regulation during the start-up of the distillation column 2 and for fine and stable control during the normal operation of the distillation column 2.

[0038] Therefore, in the above embodiment, the first diameter of the main regulating valve unit 10 reaches 75%-95% of the diameter of the steam pipeline 4. The first diameter of the main regulating valve unit 10 is close to the diameter of the steam pipeline 4, so a smooth transition section can be set between the main regulating valve unit 10 and the steam pipeline 4. When the main regulating valve unit 10 is at its maximum opening, it can reduce the turbulence and local resistance caused by the sudden change in cross-sectional area after the steam fluid flows from the main regulating valve unit 10 to the steam pipeline 4.

[0039] Furthermore, the polycrystalline silicon differential pressure coupled distillation column 100 in this application can complete the entire trichlorosilane purification process. The cooler 5, reflux pump 6, and reflux tank 7 are also core supporting equipment at the top of the distillation column 2, which together with the distillation column 2 and reboiler 3 constitute a complete separation system.

[0040] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A steam regulating valve assembly for a polycrystalline silicon differential pressure coupled distillation column, characterized in that, The steam regulating valve assembly is located on the steam pipeline to regulate the amount of steam entering the reboiler, and the steam regulating valve assembly includes: The main regulating valve unit is located on the steam pipeline and has a first flow diameter. The main regulating valve unit is used to regulate the flow rate of the main steam during the stable operation phase of the distillation column. An auxiliary regulating valve unit is provided on the steam pipeline. The auxiliary regulating valve unit has a second through-hole, which is smaller than the first through-hole. The auxiliary regulating valve unit is used for micro-flow control of steam during the start-up phase of the distillation column.

2. The steam regulating valve assembly of the polycrystalline silicon differential pressure coupled distillation column as described in claim 1, characterized in that, The sum of the first orifice of the main regulating valve unit and the second orifice of the auxiliary regulating valve unit is adapted to the maximum design flow rate of the steam pipeline.

3. The steam regulating valve assembly of the polycrystalline silicon differential pressure coupled distillation column as described in claim 1, characterized in that, The main regulating valve unit and the auxiliary regulating valve unit are located in parallel on the steam pipeline; During the stable operation phase of the distillation column, the auxiliary regulating valve unit works in conjunction with the main regulating valve unit to compensate for fluctuations in steam flow.

4. The steam regulating valve assembly of the polycrystalline silicon differential pressure coupled distillation column as described in claim 3, characterized in that, The second port diameter of the auxiliary regulating valve unit does not exceed half of the first port diameter of the main regulating valve unit.

5. The steam regulating valve assembly of the polycrystalline silicon differential pressure coupled distillation column as described in claim 4, characterized in that, The main regulating valve unit also includes multiple regulating valves, which are connected in parallel with the auxiliary regulating valve unit on the steam pipeline.

6. The steam regulating valve assembly of the polycrystalline silicon differential pressure coupled distillation column as described in claim 4, characterized in that, The main regulating valve unit also includes a first regulating valve and a second regulating valve, and the auxiliary regulating valve unit, the first regulating valve and the second regulating valve are arranged in parallel on the steam pipeline.

7. The steam regulating valve assembly of the polycrystalline silicon differential pressure coupled distillation column as described in claim 6, characterized in that, The first regulating valve has a third passage, and the second regulating valve has a fourth passage. The first passage is the sum of the third passage and the fourth passage. The third diameter of the first regulating valve is larger than the second diameter of the auxiliary regulating valve.

8. The steam regulating valve assembly of the polycrystalline silicon differential pressure coupled distillation column as described in claim 7, characterized in that, The fourth port diameter of the second regulating valve is larger than the second port diameter of the auxiliary regulating valve.

9. The steam regulating valve assembly of the polycrystalline silicon differential pressure coupled distillation column as described in claim 8, characterized in that, The first diameter of the main regulating valve unit reaches 75%-95% of the diameter of the steam pipeline.

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