Polycrystalline silicon reduction furnace bell jar cleaning system

Abstract

The utility model relates to the technical field of polycrystalline silicon production, in particular to a polycrystalline silicon reduction furnace bell jar cleaning system. The conveying pump I is communicated with the alkali liquor tank through a connecting pipeline II; a water inlet of the cleaner is communicated with a delivery pump I through a heat exchanger I; the bell jar is placed on the cleaner; a gas input channel is arranged on one side of the sight glass on the bell jar and faces the inner side face of the sight glass. The gas input channel is communicated with a nitrogen pipeline; the heat exchanger II is communicated with a compressed air pipe; the heat exchanger II is communicated with a gas inlet of the cleaner; the waste liquid tank is communicated with a material outlet of the cleaner; the waste liquid tank is provided with an emptying port and is connected with an emptying pipeline; the emptying pipeline is communicated with a material outlet of the cleaner; a nitrogen port is formed in the waste liquid tank and is communicated with a nitrogen pipeline; a liquid outlet is formed in the waste liquid tank. The safety in the cleaning process of the reduction furnace bell jar can be improved, and corrosion of cleaning alkali liquor to the sight glass is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of polysilicon production, in particular to a bell cleaning system for a polysilicon reduction furnace. Background Art

[0002] During the polysilicon production process, a certain thickness of polysilicon byproducts, silicon powder, etc. will be deposited on the surface of the bell jar of the reduction furnace; however, polysilicon production has high requirements for the cleanliness of the deposition environment of the reduction furnace. Any granular impurities, materials, etc. remaining in the furnace will affect the product quality; therefore, after the reduction furnace runs for a cycle, the bell jar needs to be cleaned. In the existing cleaning method, the bell jar is directly placed on the cleaner for cleaning. During the cleaning process, the polysilicon byproducts, silicon powder and other materials deposited on the bell jar react chemically with the alkali solution to produce flammable gas hydrogen. When hydrogen gathers, combustion and explosion accidents are prone to occur; moreover, the cleaning alkali solution stays on the sight glass for a long time during the cleaning process, which is easy to cause corrosion damage to the sight glass. Utility Model Content

[0003] In view of this, the utility model provides a polysilicon reduction furnace bell cleaning system, the main purpose of which is to improve the safety of the reduction furnace bell cleaning process and reduce the corrosion of the cleaning alkali solution to the sight glass.

[0004] In order to achieve the above purpose, the utility model mainly provides the following technical solutions:

[0005] The embodiment of the utility model provides a bell cleaning system for a polysilicon reduction furnace, comprising: a desalted water tank, an alkali liquid tank, a first delivery pump, a first heat exchanger, a cleaning device, a bell, a second heat exchanger, a waste liquid tank and a second delivery pump;

[0006] The input end of the delivery pump 1 is connected to the liquid outlet of the desalted water tank through a connecting pipeline 1; a control valve 1 is provided on the connecting pipeline 1; the input end of the delivery pump 1 is connected to the alkali liquid tank through a connecting pipeline 2; a control valve 2 is provided on the connecting pipeline 2;

[0007] The material input port of the heat exchanger 1 is connected to the output end of the delivery pump 1;

[0008] The water inlet of the cleaning device is connected to the material outlet of the heat exchanger 1;

[0009] The bell jar is placed on the washer; a sealing gasket is provided between the bell jar and the washer;

[0010] The bell jar has a sight glass; a gas input channel is provided on one side of the sight glass; the gas input channel is connected to the interior of the bell jar; one end of the gas input channel faces the inner side of the sight glass; the other end of the gas input channel is connected to the nitrogen pipeline;

[0011] The material inlet of the second heat exchanger is connected to the compressed air pipe; the material outlet of the second heat exchanger is connected to the gas inlet of the cleaning device through a gas pipeline; a control valve 4 is provided on the gas pipeline;

[0012] The liquid inlet of the waste liquid tank is connected to the material outlet of the cleaning device through pipeline 1; a control valve 3 is provided on the pipeline 1;

[0013] The waste liquid tank is provided with a vent port; the vent port is provided with a vent pipeline; the vent pipeline is connected with the material outlet of the cleaning device through pipeline 2;

[0014] The waste liquid tank is provided with a nitrogen port; the nitrogen port is connected to the nitrogen pipeline;

[0015] The waste liquid tank is provided with a liquid level detection device;

[0016] The waste liquid tank is provided with a liquid discharge port;

[0017] The input end of the second delivery pump is communicated with the liquid discharge port; the output end of the second delivery pump is connected to the liquid discharge pipeline.

[0018] Furthermore, an agitator is arranged in the waste liquid tank.

[0019] Further, the delivery pump 1 is a high-pressure plunger pump;

[0020] Furthermore, the second delivery pump is a centrifugal pump.

[0021] Furthermore, the heat exchanger 1 is a plate heat exchanger.

[0022] Furthermore, the second heat exchanger is a plate heat exchanger.

[0023] Furthermore, the alkali liquid tank is provided with a venting channel; the venting channel is connected to the venting pipeline.

[0024] By means of the above technical solution, the polysilicon reduction furnace bell cleaning system of the utility model has at least the following advantages:

[0025] It can improve the safety of the reduction furnace bell cleaning process and reduce the corrosion of the cleaning alkali solution to the sight glass.

[0026] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the utility model in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1A schematic diagram of a polysilicon reduction furnace bell jar cleaning system provided in an embodiment of the utility model.

[0028] As shown in the figure:

[0029] 1 is a desalted water tank, 2 is a control valve 1, 3 is a control valve 2, 4 is a delivery pump 1, 5 is a heat exchanger 1, 6 is a sight glass, 7 is a bell jar, 8 is a cleaning device, 9 is a control valve 3, 10 is a control valve 4, 11 is a heat exchanger 2, 12 is an alkali liquid tank, 13 is a waste liquid tank, 14 is a delivery pump 2, 15 is a liquid level detection device, and 16 is a three-waste treatment unit. DETAILED DESCRIPTION

[0030] In order to further explain the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the specific implementation methods, structures, features and effects of the utility model application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0031] like Figure 1 As shown, a cleaning system for a bell jar 7 of a polysilicon reduction furnace proposed in an embodiment of the utility model comprises: a desalted water tank 1, an alkali liquid tank 12, a delivery pump 14, a heat exchanger 15, a cleaning device 8, a bell jar 7, a heat exchanger 2 11, a waste liquid tank 13 and a delivery pump 2 14; the input end of the delivery pump 4 is connected to the liquid outlet of the desalted water tank 1 through a connecting pipeline 1; a control valve 2 is arranged on the connecting pipeline 1; the input end of the delivery pump 4 is connected to the alkali liquid tank 12 through a connecting pipeline 2; a control valve 23 is arranged on the connecting pipeline 2; preferably, the delivery pump 4 is a high-pressure plunger pump; the material input port of the heat exchanger 5 is connected to the output end of the delivery pump 4; preferably, the heat exchanger 5 is a plate heat exchanger. The water inlet of the cleaning device 8 is connected to the material output port of the heat exchanger 5 for inputting the heated cleaning liquid; the cleaning liquid (desalted water or alkali liquid) is adjusted in temperature through the heat exchanger 5 to reach the optimal temperature condition for the cleaning reaction, which can effectively improve the cleaning effect of the bell jar 7.

[0032] The bell jar 7 is placed on the cleaning device 8; a sealing gasket is arranged between the bell jar 7 and the cleaning device 8; a sight glass 6 is arranged on the bell jar 7; a gas input channel is arranged on one side of the sight glass 6; the gas input channel is connected with the interior of the bell jar 7; one end of the gas input channel faces the inner side of the sight glass 6; the other end of the gas input channel is connected with a nitrogen pipeline; nitrogen is purged toward the inner side of the sight glass 6 through the gas input channel, which can prevent the alkali solution from staying on the sight glass 6 for a long time during the cleaning process and causing corrosion to the sight glass 6; on the other hand, in the process of cleaning the bell jar 7, the alkali solution and silicon powder (Si) react to generate hydrogen (H2), and nitrogen as an inert gas can prevent hydrogen from forming an explosive mixed gas, thereby improving the safety of the entire system.

[0033] The material inlet of the heat exchanger 2 11 is connected to the compressed air pipe; the material outlet of the heat exchanger 2 11 is connected to the gas inlet of the washer 8 through a gas pipeline; preferably, the heat exchanger 2 11 is a plate heat exchanger. A control valve 4 10 is arranged on the gas pipeline; the liquid inlet of the waste liquid tank 13 is connected to the material outlet of the washer 8 through a pipeline 1; preferably, an agitator is arranged in the waste liquid tank 13, which is conducive to the full reaction of impurities such as silicon powder and reduces the risk of later operations. A control valve 3 9 is arranged on the pipeline 1; a vent is arranged on the waste liquid tank 13; a vent pipeline is arranged on the vent; the gas phase in the waste liquid tank 13 is directly vented at a high point through the vent pipeline. The vent pipeline is connected to the material outlet of the washer 8 through the pipeline 2; the material output from the washer 8 is connected to the vent pipeline through the gas phase through the pipeline 2, and is directly vented at a high point; the other way enters the waste liquid tank 13 through the pipeline 1. The waste liquid tank 13 is used to replace the sedimentation tank. The waste liquid tank 13 has high airtightness and effectively improves the safety of the site.

[0034] Preferably, the alkali liquid tank 12 is provided with a nitrogen inlet, which is connected to the nitrogen pipeline. The alkali liquid tank 12 is provided with a venting channel; the venting channel is connected to the venting pipeline. The venting channel of the waste alkali liquid is emptied after merging with the venting pipeline at the middle position. In winter, when the alkali liquid tank 12 is emptied separately through the venting pipeline, it is easy to freeze at the end and cause blockage. After merging, when the washer 8 is drying, hot air can effectively prevent the problem of ice blockage in winter.

[0035] The waste liquid tank 13 is provided with a nitrogen port; the nitrogen port is connected to the nitrogen pipeline, and is used to introduce nitrogen for positive pressure protection, which can effectively prevent hydrogen from gathering in the tank to form an explosive mixed gas. By using nitrogen replacement, high-point venting is carried out in time, which improves the safety of the entire system. The waste liquid tank 13 is provided with a liquid level detection device 15; the waste liquid tank 13 has a liquid discharge port; the input end of the delivery pump 14 is connected to the liquid discharge port; preferably, the delivery pump 14 is a centrifugal pump. The output end of the delivery pump 14 is connected to the liquid discharge pipeline, and the generated waste liquid is sent to the three waste treatment unit 16 for treatment, and the acidic liquid generated by the hydrolysis of chlorosilane is neutralized, thereby reducing the alkali consumption of the three waste treatment unit 16.

[0036] An embodiment of the utility model provides a polysilicon reduction furnace bell 7 cleaning system, which can improve the safety of the reduction furnace bell 7 cleaning process and reduce the corrosion of the cleaning liquid to the sight glass 6.

[0037] An embodiment of the utility model provides a cleaning system for a bell jar 7 of a polysilicon reduction furnace. The entire system can realize automatic control, thereby reducing the labor intensity of operators.

[0038] Further explanation, although the terms first, second, etc. can be used to describe various elements in this article, these terms should not limit these elements. These terms are only used to distinguish one element from another element. For example, the first element can be called the second element, and, similarly, the second element can be called the first element, and these terms are only used to distinguish one element from another element. This does not depart from the scope of exemplary embodiments. Similarly, element one and element two do not represent the order of elements, and these terms are only used to distinguish one element from another element. As used herein, the term "and / or" includes any combination and all combinations of one or more associated listed items.

[0039] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] The standard parts used in the utility model can all be purchased from the market, and special-shaped parts can be customized according to the instructions and the drawings. The specific connection methods of each part adopt the conventional means such as mature bolts, rivets, welding, etc. in the existing technology. The machinery, parts and equipment all adopt the conventional models in the existing technology, and the circuit connection adopts the conventional connection method in the existing technology, which will not be described in detail here.

[0041] The above is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A polysilicon reduction furnace bell cleaning system, characterized in that: Including: desalted water tank, alkali liquid tank, delivery pump 1, heat exchanger 1, cleaning device, bell jar, heat exchanger 2, waste liquid tank and delivery pump 2; The input end of the delivery pump 1 is connected to the liquid outlet of the desalted water tank through a connecting pipeline 1; a control valve 1 is provided on the connecting pipeline 1; the input end of the delivery pump 1 is connected to the alkali liquid tank through a connecting pipeline 2; a control valve 2 is provided on the connecting pipeline 2; The material input port of the heat exchanger 1 is connected to the output end of the delivery pump 1; The water inlet of the cleaning device is connected to the material outlet of the heat exchanger 1; The bell jar is placed on the washer; a sealing gasket is provided between the bell jar and the washer; The bell jar has a sight glass; a gas input channel is provided on one side of the sight glass; the gas input channel is connected to the interior of the bell jar; one end of the gas input channel faces the inner side of the sight glass; the other end of the gas input channel is connected to the nitrogen pipeline; The material inlet of the second heat exchanger is connected to the compressed air pipe; the material outlet of the second heat exchanger is connected to the gas inlet of the cleaning device through a gas pipeline; a control valve 4 is provided on the gas pipeline; The liquid inlet of the waste liquid tank is connected to the material outlet of the cleaning device through pipeline 1; a control valve 3 is provided on the pipeline 1; The waste liquid tank is provided with a vent port; the vent port is provided with a vent pipeline; the vent pipeline is connected with the material outlet of the cleaning device through pipeline 2; The waste liquid tank is provided with a nitrogen port; the nitrogen port is connected to the nitrogen pipeline; The waste liquid tank is provided with a liquid level detection device; The waste liquid tank is provided with a liquid discharge port; The input end of the second delivery pump is communicated with the liquid discharge port; the output end of the second delivery pump is connected to the liquid discharge pipeline.

2. The polysilicon reduction furnace bell cleaning system according to claim 1, characterized in that: A stirrer is arranged in the waste liquid tank.

3. The polysilicon reduction furnace bell cleaning system according to claim 1, characterized in that: The first delivery pump is a high-pressure plunger pump.

4. The polysilicon reduction furnace bell cleaning system according to claim 1, characterized in that: The second delivery pump is a centrifugal pump.

5. The polysilicon reduction furnace bell cleaning system according to claim 1, characterized in that: The first heat exchanger is a plate heat exchanger.

6. The polysilicon reduction furnace bell cleaning system according to claim 1, characterized in that: The second heat exchanger is a plate heat exchanger.

7. The polysilicon reduction furnace bell cleaning system according to claim 1, characterized in that: The alkali liquid tank is provided with a venting channel; the venting channel is communicated with the venting pipeline.

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