Device for circularly removing boron and phosphorus from chlorosilane of cold hydrogenation product

Abstract

The utility model discloses a device for circularly removing boron and phosphorus from cold hydrogenated product chlorosilane. The device comprises a chlorosilane product storage tank, a chlorosilane circulating liquid pump, a filter, an impurity removal device and a chlorosilane produced liquid pump, the chlorosilane product storage tank, the chlorosilane circulating liquid pump, the filter and the impurity removal device are sequentially connected through a loop pipeline, and a discharged material of the impurity removal device is reconnected into the chlorosilane product storage tank through the loop pipeline; and the chlorosilane product storage tank is connected with the chlorosilane produced liquid pump through a production pipeline. Boron and phosphorus impurities in chlorosilane are removed in a circulating impurity removal mode, the impurity content can be reduced to meet the standard, and impurity removal devices such as excessive adsorption columns do not need to be arranged.

Description

Technical Field

[0001] The utility model belongs to the field of polysilicon production, and specifically relates to a cold hydrogenation product chlorosilane circulating boron and phosphorus removal device. Background Art

[0002] In the current mainstream production process of crystalline silicon, whether it is the modified Siemens method or the silane gas method, the impurity content of the cold hydrogenation product chlorosilane affects the quality of the final product silicon. Under normal working conditions, the cold hydrogenation device will continuously introduce impurities from the industrial silicon powder, which is inevitable. When the quality of the cold hydrogenation product chlorosilane fluctuates greatly, the impurity content increases, and the quality of the final product silicon will also decrease. The large fluctuations in the cold hydrogenation product chlorosilane usually occur in a certain production line, and the reasons are generally the production conditions such as the bed falling, surging or device shutdown of the cold hydrogenation fluidized bed reactor. Most of the existing processes use centralized impurity removal to remove boron and phosphorus impurities in the cold hydrogenation product chlorosilane before entering the distillation tower for further purification. However, when abnormal working conditions occur, the processing capacity of the impurity removal device is too large, resulting in a large amount of impurities being brought into the silicon material, affecting the product quality. In order to meet the impurity removal needs of abnormal working conditions, the redundancy of the impurity removal device can also be increased, but the cost will be greatly increased. Summary of the invention

[0003] Purpose of the utility model: The technical problem to be solved by the utility model is to provide a boron and phosphorus removal device in view of the deficiencies of the prior art, which can solve the problem of increased content of impurities such as chlorosilane, boron and phosphorus in the cold hydrogenation product and excessive processing capacity of the impurity removal device when abnormal working conditions occur at a relatively low cost, thereby ensuring the quality of the product silicon material.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0005] A cold hydrogenation product chlorosilane circulating boron and phosphorus removal device comprises a chlorosilane product storage tank, a chlorosilane circulating liquid pump, a filter, an impurity removal device and a chlorosilane produced liquid pump; the chlorosilane product storage tank, the chlorosilane circulating liquid pump, the filter and the impurity removal device are connected in sequence through a loop pipeline, and the impurity removal device discharge is reconnected to the chlorosilane product storage tank through the loop pipeline; the chlorosilane product storage tank and the chlorosilane produced liquid pump are connected through a produced pipeline.

[0006] Specifically, the bottom of the chlorosilane product storage tank is connected to the cold hydrogenation device through a feed pipeline.

[0007] Preferably, the loop pipeline is led out from the side of the chlorosilane product storage tank, returns after passing through a filter and an impurity removal device, and is connected to the bottom of the chlorosilane product storage tank.

[0008] Preferably, the production pipeline is led out from the side of the chlorosilane product storage tank and connected to a subsequent distillation device after passing through a chlorosilane production liquid pump.

[0009] Furthermore, the filters are at least two groups, which are connected in parallel to the rear end of the chlorosilane circulating liquid pump; the output from the rear end of each filter is collected through a main pipe and connected to the impurity removal device.

[0010] Furthermore, the impurity removal devices are at least two groups, which are connected in parallel to the rear end of the filter; the output from the rear end of each impurity removal device is collected through a main pipe and connected to the loop pipeline.

[0011] Preferably, the filter is a bag filter type solid particle filter, which is used to filter solid particles in chlorosilane to prevent the solid particles from affecting the operation of the impurity removal device and the pump.

[0012] Preferably, the impurity removal device is an activated carbon or resin boron and phosphorus removal adsorption column that combines physical adsorption with chemical adsorption.

[0013] Furthermore, material valves are provided at the front end and the rear end of each filter.

[0014] Furthermore, material valves are provided at the front and rear ends of each impurity removal device. Beneficial Effects

[0015] (1) This device uses a cyclic impurity removal method to remove boron and phosphorus impurities in chlorosilane, which can reduce the impurity content to a level that meets the standard without the need to set up too many adsorption columns and other impurity removal devices.

[0016] (2) This device is semi-intermittently operated. When the impurity content of chlorosilane, boron, phosphorus and other impurities in the cold hydrogenation product is low, there is no need to start this device. At this time, if the service life of the filter and the impurity removal device is reached, they can be replaced in time, and the impact on the operation of other devices is minimal. Two or more filters and impurity removal devices are set up. Depending on the level of impurities, one or more can be selected to be enabled to extend the operation cycle of the device. When a single filter and impurity removal device is enabled, the filter and impurity removal device that need to be repaired can also be repaired in time to ensure its impurity removal efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation methods, and the above and / or other advantages of the present invention will become more clear.

[0018] Figure 1 It is a schematic diagram of the overall structure of the device.

[0019] Wherein, each reference numeral represents:

[0020] 1-Chlorosilane product storage tank; 2-Chlorosilane circulating liquid pump; 3-Filter; 4-Impurity removal device; 5-Chlorosilane produced liquid pump; 6-Distillation device; 7-Cold hydrogenation device; 10-Loop pipeline; 20-Production pipeline; 30-Feed pipeline. DETAILED DESCRIPTION

[0021] The present invention can be better understood according to the following embodiments.

[0022] The structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the utility model, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that can be achieved by the utility model, should still fall within the scope of the technical content disclosed by the utility model. At the same time, the terms such as "upper", "lower", "front", "back", "middle" and so on quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the utility model. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the utility model without substantial change of the technical content.

[0023] Combination Figure 1 The utility model provides a cold hydrogenation product chlorosilane circulating boron and phosphorus removal device, comprising a chlorosilane product storage tank 1, a chlorosilane circulating liquid pump 2, a filter 3, an impurity removal device 4 and a chlorosilane produced liquid pump 5; the chlorosilane product storage tank 1, the chlorosilane circulating liquid pump 2, the filter 3, and the impurity removal device 4 are connected in sequence through a loop pipeline 10, and the discharge of the impurity removal device 4 is reconnected to the chlorosilane product storage tank 1 through the loop pipeline 10; the chlorosilane product storage tank 1 and the chlorosilane produced liquid pump 5 are connected through a production pipeline 20.

[0024] In this embodiment, the bottom of the chlorosilane product storage tank 1 is connected to the cold hydrogenation device 7 through a feed pipeline 30 .

[0025] In this embodiment, the loop pipe 10 is led out from the side of the chlorosilane product storage tank 1 , passes through the filter 3 and the impurity removal device 4 , and then returns to be connected to the bottom of the chlorosilane product storage tank 1 .

[0026] In this embodiment, the production pipeline 20 is led out from the side of the chlorosilane product storage tank 1 and connected to the subsequent distillation device 6 after passing through the chlorosilane production liquid pump 5.

[0027] In this embodiment, the filters 3 are at least two groups, which are connected in parallel to the rear end of the chlorosilane circulating liquid pump 2; the output from the rear end of each filter 3 is collected through a main pipe and connected to the impurity removal device 4.

[0028] In this embodiment, there are at least two groups of impurity removal devices 4 connected in parallel to the rear end of the filter 3 ; the output from the rear end of each impurity removal device 4 is collected through a main pipe and connected to the loop pipeline 10 .

[0029] In this embodiment, the filter 3 is a bag-type solid particle filter.

[0030] In this embodiment, the impurity removal device 4 is an activated carbon boron and phosphorus removal adsorption column that combines physical adsorption and chemical adsorption.

[0031] In this embodiment, material valves are provided at the front end and the rear end of each filter 3 .

[0032] In this embodiment, material valves are provided at the front end and the rear end of each impurity removal device.

[0033] When in use, the product chlorosilane with high impurity content from the cold hydrogenation device 7 is sent to the chlorosilane product storage tank 1, and is pumped into the filter 3 through the chlorosilane circulating liquid pump 2 to remove the solid particles contained in the liquid phase, and then enters the impurity removal device 4 to remove impurities mainly including boron and phosphorus, and finally returns to the chlorosilane product storage tank 1. If the impurity content of chlorosilane in the chlorosilane product storage tank 1 is low, it is transported to the distillation device 6 through the chlorosilane produced liquid pump 5; if the impurity removal standard is not reached, the circulation continues until the impurity content drops to meet the standard.

[0034] The utility model provides a concept and method for a cold hydrogenation product chlorosilane circulation boron and phosphorus removal device. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the utility model. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model. These improvements and modifications should also be regarded as the protection scope of the utility model. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A cold hydrogenation product chlorosilane circulation boron and phosphorus removal device, characterized in that: The invention comprises a chlorosilane product storage tank (1), a chlorosilane circulating liquid pump (2), a filter (3), an impurity removal device (4) and a chlorosilane produced liquid pump (5); the chlorosilane product storage tank (1), the chlorosilane circulating liquid pump (2), the filter (3) and the impurity removal device (4) are connected in sequence via a loop pipeline (10); the discharge of the impurity removal device (4) is reconnected to the chlorosilane product storage tank (1) via the loop pipeline (10); the chlorosilane product storage tank (1) and the chlorosilane produced liquid pump (5) are connected via a produced pipeline (20).

2. The cold hydrogenation product chlorosilane circulation boron and phosphorus removal device according to claim 1, characterized in that: The bottom of the chlorosilane product storage tank (1) is connected to the cold hydrogenation device (7) via a feed pipeline (30).

3. The cold hydrogenation product chlorosilane circulation boron and phosphorus removal device according to claim 1, characterized in that: The loop pipe (10) is led out from the side of the chlorosilane product storage tank (1), passes through a filter (3) and an impurity removal device (4), returns, and is connected to the bottom of the chlorosilane product storage tank (1).

4. The cold hydrogenation product chlorosilane circulation boron and phosphorus removal device according to claim 1, characterized in that: The production pipeline (20) is led out from the side of the chlorosilane product storage tank (1) and connected to the subsequent distillation device (6) after passing through the chlorosilane production liquid pump (5).

5. The cold hydrogenation product chlorosilane circulation boron and phosphorus removal device according to claim 1, characterized in that: The filters (3) are at least two groups, which are connected in parallel to the rear end of the chlorosilane circulating liquid pump (2); the output from the rear end of each filter (3) is collected through a main pipe and connected to the impurity removal device (4).

6. The cold hydrogenation product chlorosilane circulation boron and phosphorus removal device according to claim 1, characterized in that: The impurity removal devices (4) are at least two groups, which are connected in parallel to the rear end of the filter (3); the output from the rear end of each impurity removal device (4) is collected through a main pipe and connected to the loop pipeline (10).

7. The device for removing boron and phosphorus from cold hydrogenated chlorosilane circulation according to claim 1, characterized in that: The filter (3) is a bag-type solid particle filter, which is used to filter solid particles in chlorosilane to prevent the solid particles from affecting the operation of the impurity removal device and the pump.

8. The cold hydrogenation product chlorosilane circulation boron and phosphorus removal device according to claim 1, characterized in that: The impurity removal device (4) is an activated carbon or resin boron and phosphorus removal adsorption column that combines physical adsorption and chemical adsorption.

9. The device for removing boron and phosphorus from cold hydrogenated chlorosilane circulation according to claim 5, characterized in that: A material valve is provided at the front end and the rear end of each filter (3).

10. The device for removing boron and phosphorus from cold hydrogenated chlorosilane circulation according to claim 6, characterized in that: Material valves are provided at the front and rear ends of each impurity removal device.

Images