Silane recovery system

Abstract

The utility model provides a silane recovery system and relates to the technical field of silane gas production. The recycling system comprises a reaction tower, a feeding pipeline and a discharging pipeline which are communicated with the reaction tower, a light component removal tower is communicated with the reaction tower through a pipeline, a product tower is communicated with the reaction tower and the light component removal tower through a pipeline, a first storage tank is communicated with the product tower through a pipeline, and a filling unit is communicated with the first storage tank through a pipeline. And the second storage tank is communicated with the first storage tank, the light component removal tower, the product tower and the filling unit through pipelines. The silane recovery device improves the recovery efficiency and purity of silane.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of silane gas production, and particularly relates to a silane recovery system. BACKGROUND

[0002] Silane (monosilane) is used as a basic raw material for preparing granular polycrystalline silicon by fluidized bed method and preparing rod-shaped polycrystalline silicon by improved Siemens method, and a large amount of tail gas is generated in the preparation process. The tail gas mainly contains hydrogen and a small amount of silane and methane and other carbon-containing compound impurities. In the traditional tail gas treatment process, the tail gas is often directly discharged, which not only leads to waste of silane resources, but also increases the environmental burden.

[0003] To solve this problem, the existing silane waste gas treatment process mainly includes three steps of waste gas collection, waste gas purification and waste gas discharge. In the waste gas collection stage, the generated silane waste gas is collected from the production equipment through pipelines to ensure that the waste gas can be effectively transported to the waste gas treatment equipment. In the waste gas purification stage, harmful components in the silane waste gas are removed by chemical adsorption, catalytic oxidation, plasma treatment or combined process. Common adsorbents include activated carbon and molecular sieve, common catalysts include copper, iron, etc., and common plasma treatment methods include corona discharge. In the waste gas discharge stage, the waste gas after purification is discharged into the atmosphere, and it is ensured that the waste gas discharge meets the national and local environmental protection standards.

[0004] However, these traditional waste gas treatment processes have obvious deficiencies in silane recovery. On the one hand, the recovery efficiency of silane is not high, and a large amount of silane resources is wasted; on the other hand, the purity of recovered silane is not high, which is difficult to meet the demand of high-purity polycrystalline silicon preparation. Therefore, developing an efficient silane recovery system to improve the recovery efficiency and purity of silane has become a problem to be solved in the field of silane gas production. UTILITY MODEL CONTENTS

[0005] The utility model aims at developing a silane recovery system for improving the recovery efficiency and purity of silane.

[0006] The utility model is realized by the following technical scheme:

[0007] A silane recovery system comprises:

[0008] A reaction tower;

[0009] A feed pipe and a discharge pipe are connected to the reaction tower;

[0010] A light component removal tower is connected to the reaction tower by a pipeline;

[0011] A product tower is connected to the reaction tower and the light component removal tower by a pipeline;

[0012] The first storage tank is communicated with the product tower pipeline;

[0013] The filling unit is communicated with the first storage tank pipeline;

[0014] The recovery system further comprises a second storage tank, which is communicated with the first storage tank, the light-removing tower, the product tower and the filling unit pipeline.

[0015] Optionally, the first gas pipe is communicated between the top of the first storage tank and the second storage tank, and a condenser is arranged on the first gas pipe.

[0016] Optionally, the second gas pipe is communicated between the filling unit and the second storage tank.

[0017] Optionally, the third gas pipe is communicated with the top of the second storage tank, and the light-removing tower and the product tower are communicated with the third gas pipe.

[0018] Optionally, the second circulating pipeline and the third circulating pipeline are respectively communicated with the top and the upper part of the light-removing tower and the product tower, a condenser communicated with the third gas pipe is arranged on the second circulating pipeline and the third circulating pipeline, and the top of the first storage tank is communicated with the outlet end of the condenser in the third circulating pipeline.

[0019] Optionally, the gas return pipe is communicated with the top of the second storage tank, the gas return pipe is communicated with the light-removing tower, and the recovery pipe is communicated between the gas return pipe and the filling unit.

[0020] Optionally, the first circulating pipeline is arranged on the top of the reaction tower, the first circulating pipeline is respectively communicated with the top and the upper part of the reaction tower, a condenser and a buffer tank are sequentially arranged on the first circulating pipeline, the buffer tank is communicated with the upper part of the light-removing tower through the conveying pipe arranged on the top of the buffer tank, the first compressor is arranged on the conveying pipe, and the gas return pipe is communicated with the inlet end of the first compressor.

[0021] Optionally, the exhaust pipe is communicated with the top of the second storage tank, a condenser is arranged on the exhaust pipe, and the exhaust pipe is communicated with the flare.

[0022] Optionally, the heating unit is arranged between the first storage tank and the second storage tank, the heating unit comprises a heater, and the inlet side and the outlet side of the heater are communicated with the first storage tank and the second storage tank pipeline.

[0023] Optionally, the valve is arranged on the pipeline between the second storage tank and the inlet side and the outlet side of the heater, and the valve is arranged on the pipeline between the second storage tank and the light-removing tower, the product tower and the filling unit.

[0024] The beneficial effects of the utility model are as follows:

[0025] The utility model discloses the tail gas and the tail material replacement of silane filling process, unloading tail gas in the production process of silane are recovered, and the recovered silane is brought into the production flow again, not only reduces the raw material consumption, but also directly reduces the overall energy consumption, and the economic benefit of production is improved significantly, and the recovery efficiency is high, and the silane purity is high, the device construction and operating cost required by tail gas leaching and processing are reduced significantly, potential safety hazards are avoided effectively through the recovery of the discharge of silane filling process, the safety risk that can be caused by direct discharge is reduced significantly, and the safety of production operation is enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0027] Figure 1 The utility model structural drawing.

[0028] Reference signs: 1, reaction tower;2, light removal tower;3, product tower;4, first circulating pipeline;5, second circulating pipeline;6, third circulating pipeline;7, first compressor;8, return gas pipe;9, third gas pipe;10, first gas pipe;11, second gas pipe;12, first storage tank;13, second storage tank;14, exhaust pipe;15, heater;16, second compressor;17, filling unit;18, recovery pipe. DETAILED DESCRIPTION

[0029] In the following, only some exemplary embodiments are simply described. As those skilled in the art can realize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0030] In the present application, unless otherwise explicitly specified and limited, the "on" or "under" of the first feature to the second feature can include that the first and second features are in direct contact, or the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "on", "above" and "above" of the first feature to the second feature include that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "under", "below" and "below" of the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0031] The embodiments of the utility model will be described below in detail with reference to the drawings.

[0032] As Figure 1 The utility model discloses a silane recovery system, including reaction tower 1, remove light tower 2, product tower 3, first storage tank 12, second storage tank 13 and filling unit 17, reaction tower 1, remove light tower 2 and product tower 3 all are equipped with reboiler. Reaction tower 1 is equipped with feed pipe line and discharge pipe line, and the bottom of remove light tower 2 and product tower 3 are communicated with pipe line, and the bottom of product tower 3 and reaction tower 1 are communicated with pipe line.

[0033] Reaction tower 1, remove light tower 2 and product tower 3 top are communicated with first circulation pipe line 4, second circulation pipe line 5 and third circulation pipe line 6 respectively, and the both ends of first circulation pipe line 4, second circulation pipe line 5 and third circulation pipe line 6 are communicated with the top and upper portion of reaction tower 1, remove light tower 2 and product tower 3 respectively. Condenser and buffer tank are sequentially arranged on first circulation pipe line 4, and condenser is arranged on second circulation pipe line 5 and third circulation pipe line 6. The top of buffer tank and the upper portion of remove light tower 2 are communicated with conveying pipe, and first compressor 7 is arranged on the conveying pipe.

[0034] Heating unit is arranged between first storage tank 12 and second storage tank 13, and the heating unit comprises heater 15, the inlet side and the outlet side of heater 15 are communicated with the pipe line of first storage tank 12 and second storage tank 13, and the material in first storage tank 12 and second storage tank 13 is refluxed after being heated by heater 15. The outlet side of heater 15 is also communicated with second compressor 16, and second compressor 16 is communicated with filling unit 17.

[0035] The top of first storage tank 12 and the outlet end of condenser in third circulation pipe line 6 are communicated with pipe line, and the top of first storage tank 12 and second storage tank 13 are communicated with first gas pipe 10, and condenser is arranged on first gas pipe 10, and filling unit 17 and second storage tank 13 are communicated with second gas pipe 11, and the top of second storage tank 13 is also communicated with third gas pipe 9, and the condensers of second circulation pipe line 5 and third circulation pipe line 6 are all communicated with third gas pipe 9.

[0036] The top of second storage tank 13 is also communicated with exhaust pipe 14 and back gas pipe 8, condenser is arranged on exhaust pipe 14, exhaust pipe 14 is communicated with torch, and back gas pipe 8 is communicated with the inlet side of first compressor 7.

[0037] Valves are arranged on the pipelines between the second storage tank 13 and the inlet side and the outlet side of the heater 15, and on the back gas pipeline 8, the second gas pipeline 11, the third gas pipeline 9 and the exhaust pipeline 14, so that the second storage tank 13 can not only recover tail gas, but also be used as a buffer tank during normal filling. When the second storage tank 13 is filled, the valves on the pipelines between the second storage tank 13 and the inlet side and the outlet side of the heater 15 are all opened, and the other valves are all closed. Conversely, when the second storage tank 13 recovers tail gas, the valves on the pipelines between the second storage tank 13 and the inlet side and the outlet side of the heater 15 are all closed, and the other valves are all opened.

[0038] The tail gas replaced by the light-removing tower 2, the product tower 3 and the filling unit 17 is recovered to the second storage tank 13 through the third gas pipeline 9 and the second gas pipeline 11. When the pressure in the second storage tank 13 reaches the inlet pressure of the first compressor 7, the tail gas can be directly transported to the first compressor 7. The tail gas enters the light-removing tower 2 for further purification. The purified silane gas enters the first storage tank 12 through cooling, and the non-condensable gas is discharged to the second storage tank 13. The non-condensable gas in the second storage tank 13 is discharged to a flare for burning after being cooled again.

[0039] The second gas pipeline 11 is provided with a recovery pipeline 18 between the second gas pipeline 11 and the back gas pipeline 8, and the recovery pipeline 18 is provided with a valve.

[0040] When the tail gas silane of the filling unit 17 and the silane in the tank car are unqualified, the unqualified silane can be recovered to the second storage tank 13 through the recovery pipeline 18 for purification, and then the silane can be recovered to the first compressor 7 through the back gas pipeline 8 for further purification. When the tail gas silane of the filling unit 17 and the silane in the tank car need to be further purified, the silane can be directly recovered to the first compressor 7 through the recovery pipeline 18 and the back gas pipeline 8.

[0041] The utility model discloses the tail gas produced in the silane production process and the tail gas replaced by the tail gas during the silane filling process and the tank car are recovered. The recovered silane is re-included in the production process, which not only reduces the raw material consumption, but also directly reduces the overall energy consumption, significantly improves the economic benefit of production, has high recovery efficiency, has high silane purity, significantly reduces the device construction and operation cost required for tail gas washing and treatment, effectively avoids potential safety hazards by recovering the discharge during the silane filling process, significantly reduces the safety risk caused by direct discharge, and enhances the safety of production operation.

[0042] The above-mentioned embodiments are only preferred embodiments of the utility model, and do not limit the technical solutions of the utility model. Any technical solution that can be realized on the basis of the above-mentioned embodiments without creative labor should be considered to fall within the protection scope of the utility model patent.

Claims

1. A silane recovery system, characterized in that, include: Reaction tower; The feed pipeline and the discharge pipeline are connected to the reaction tower; The light-weight removal tower is connected to the reaction tower via pipeline; The product tower is connected to the reaction tower and the light-weight product removal tower via pipelines. The first storage tank is connected to the product tower pipeline; The filling unit is connected to the pipeline of the first storage tank; The recycling system also includes a second storage tank, which is connected to the first storage tank, the light-weight removal tower, the product tower, and the filling unit pipeline.

2. The silane recovery system according to claim 1, characterized in that, A first gas pipe is connected between the top of the first storage tank and the second storage tank, and a condenser is installed on the first gas pipe.

3. The silane recovery system according to claim 1, characterized in that, The filling unit is connected to the second storage tank by a second gas pipe.

4. The silane recovery system according to claim 1, characterized in that, The top of the second storage tank is connected to a third gas pipe, and the light-weight removal tower and product tower are connected to the third gas pipe.

5. The silane recovery system according to claim 4, characterized in that, The top of the light-light removal tower and the product tower are respectively connected to a second circulation pipeline and a third circulation pipeline. The two ends of the second circulation pipeline and the third circulation pipeline are respectively connected to the top and upper part of the light-light removal tower and the product tower. Both the second circulation pipeline and the third circulation pipeline are equipped with condensers connected to the third gas pipe. The top of the first storage tank is connected to the outlet end of the condenser in the third circulation pipeline.

6. The silane recovery system according to claim 1, characterized in that, The top of the second storage tank is connected to a return gas pipe, which is connected to the light-duty removal tower, and a recovery pipe is connected between the return gas pipe and the filling unit.

7. The silane recovery system according to claim 6, characterized in that, The top of the reaction tower is provided with a first circulation pipeline, the two ends of which are connected to the top and upper part of the reaction tower, respectively. A condenser and a buffer tank are sequentially arranged on the first circulation pipeline. The top of the buffer tank is connected to the upper part of the light-duty removal tower by a conveying pipe. A first compressor is provided on the conveying pipe. The return gas pipe is connected to the inlet end of the first compressor.

8. The silane recovery system according to claim 1, characterized in that, The top of the second storage tank is connected to an exhaust pipe, which is equipped with a condenser and is connected to a flare.

9. The silane recovery system according to any one of claims 1 to 8, characterized in that, A heating unit is provided between the first storage tank and the second storage tank. The heating unit includes a heater, and the inlet and outlet sides of the heater are connected to the pipelines of the first storage tank and the second storage tank.

10. The silane recovery system according to claim 9, characterized in that, Valves are installed on the pipeline between the second storage tank and the inlet and outlet sides of the heater, and valves are also installed on the pipeline between the second storage tank and the light removal tower, the product tower and the filling unit.

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