A device for recovering silane from tail gas

Abstract

The present invention discloses a device for recovering silane in tail gas, comprising an absorption tower, a condenser and a gas-liquid separator, wherein a filler is provided in the absorption tower, the condenser is provided in the absorption tower, and the gas-liquid separator is connected to the absorption tower; an absorption liquid containing chlorosilane enters the absorption tower from the upper part of the filler, and the tail gas containing silane enters the absorption tower from the lower part of the filler; the tail gas containing silane and the absorption liquid containing chlorosilane are absorbed and separated inside the filler, and the absorbed absorption liquid is discharged from the absorption tower, and the separated tail gas is condensed by the condenser and then enters the gas-liquid separator for sedimentation and then discharged from the absorption tower. The present invention uses the absorption, condensation and sedimentation of silane in tail gas in series, thereby improving the recovery rate of silane in tail gas while reducing the loss of absorption liquid, thereby minimizing the overall material loss.

Description

Technical Field

[0001] The present invention relates to the technical field of silane recovery, in particular to a device for recovering silane from tail gas. Background Art

[0002] Silicon-based materials are the most important basic materials for the electronic information industry and the solar photovoltaic power generation industry. Polysilicon currently used in solar photovoltaic power generation is an efficient, environmentally friendly and clean new energy technology.

[0003] Silane, the primary raw material in granular silicon production, directly impacts production costs. The presence of silane in tail gas emissions can lead to silane losses and increased production costs. Recovering silane from tail gas is one way to reduce production costs. Traditional condensation separation and recovery methods suffer from low condensation temperatures, long condensation chains, unstable control, complex equipment, and demanding requirements. Furthermore, the presence of chlorosilane can cause system "ice blockages," impacting continuous production. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a device for recovering silane in tail gas to solve the problems of low condensation temperature, long condensation chain, unstable control, multiple equipment and high requirements, easy ice blockage and discontinuous production in traditional condensation separation and recovery of silane in tail gas.

[0005] To solve the above technical problems, the present invention is implemented by adopting the following solutions:

[0006] The present invention provides a device for recovering silane in tail gas, comprising an absorption tower, a condenser and a gas-liquid separation tank, wherein fillers are arranged in the absorption tower, the condenser is arranged in the absorption tower, and the gas-liquid separation tank is connected to the absorption tower;

[0007] The absorption liquid containing chlorosilane enters the absorption tower from the upper part of the packing, and the tail gas containing silane enters the absorption tower from the lower part of the packing. The tail gas containing silane and the absorption liquid containing chlorosilane are absorbed and separated inside the packing. The absorbed absorption liquid is discharged from the absorption tower. The separated tail gas is condensed in the condenser and then enters the gas-liquid separation tank for sedimentation before being discharged from the absorption tower.

[0008] Furthermore, it also includes a Johnson net, which is arranged at the outlet of the condenser and is used for primary defoaming and sedimentation of the condensed tail gas.

[0009] Furthermore, it also includes a baffle, which is arranged at the inlet of the gas-liquid separation tank and is used to remove foam and settle the condensed tail gas again.

[0010] Furthermore, it also includes a demister, which is arranged on the top of the gas-liquid separation tank and is used to demister and settle the condensed tail gas again.

[0011] Furthermore, the demister is a wire mesh demister.

[0012] Furthermore, the absorption liquid discharged from the absorption tower is returned to the vaporization separation tower to separate out the silane.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. Compared with condensation separation, the present invention uses chlorosilane for absorption and condensation separation, which can not only avoid ice blockage, but also reduce equipment investment because the equipment is less and the long-chain condensation is more stable.

[0015] 2. The present invention uses the absorption, condensation, and sedimentation of silane in tail gas in series, thereby improving the recovery rate of silane in tail gas while reducing the loss of absorption liquid, thereby minimizing the overall material loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 1 is a schematic structural diagram of a device for recovering silane from tail gas provided by an embodiment of the present invention;

[0017] In the figure: 1. Absorption tower; 2. Condenser; 3. Gas-liquid separation tank; 4. Johnson net; 5. Baffle; 6. Wire mesh demister; 7. Packing. Implementation Method

[0018] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0019] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0021] like Figure 1As shown, this embodiment provides a device for recovering silane in exhaust gas, which consists of an absorption tower 1, a condenser 2 and a gas-liquid separation tank 3. Compared with condensation separation, the device for recovering silane in exhaust gas uses chlorosilane for absorption and condensation separation, which can not only avoid ice blockage but also reduce equipment investment because the equipment is less and the long-chain condensation is more stable; the absorption, condensation and sedimentation of silane in exhaust gas are used in series to improve the recovery rate of silane in exhaust gas while reducing the loss of absorption liquid, so that the overall material loss is minimized.

[0022] Specifically, a filler 7 is provided in the absorption tower 1 , the condenser 2 is provided in the absorption tower 1 , and the gas-liquid separation tank 3 is connected to the absorption tower 1 . An absorption liquid (a solution containing chlorosilane, which mainly absorbs silane in the tail gas and does not react with silane) of a certain temperature, pressure and flow rate enters the absorption tower 1 from the upper part of the packing 7, and the tail gas containing silane enters the absorption tower 2 from the lower part of the packing 7. The tail gas containing silane and the absorption liquid containing chlorosilane are absorbed and separated inside the packing 7, thereby reducing the silane content in the tail gas. The absorbed absorption liquid is discharged from the bottom of the absorption tower 1 from the absorption tower 1. After separation, a small amount of silane contained in the tail gas is condensed by the condenser 2, and then the Johnson net 4 installed at the outlet of the condenser 2 is used for initial defoaming and sedimentation, and then enters the gas-liquid separation tank 3 with a baffle 5. The baffle 5 is set at the inlet of the gas-liquid separation tank 3. A wire mesh demister 6 is also provided on the top of the gas-liquid separation tank 3 to settle the tiny absorption liquid droplets again to ensure that the concentration of absorption liquid and silane in the discharged tail gas is the lowest. Finally, the tail gas without silane is discharged from the top of the gas-liquid separation tank 3.

[0023] In addition, the absorption liquid discharged from the absorption tower 1 is returned to the vaporization separation tower for analysis, and the silane is analyzed and used as a product.

[0024] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A device for recovering silane from tail gas, characterized in that: It includes an absorption tower, a condenser and a gas-liquid separation tank, wherein the absorption tower is provided with fillers, the condenser is provided in the absorption tower, and the gas-liquid separation tank is connected to the absorption tower; The absorption liquid containing chlorosilane enters the absorption tower from the upper part of the packing, and the tail gas containing silane enters the absorption tower from the lower part of the packing. The tail gas containing silane and the absorption liquid containing chlorosilane are absorbed and separated inside the packing. The absorbed absorption liquid is discharged from the absorption tower. The separated tail gas is condensed in the condenser and then enters the gas-liquid separation tank for sedimentation before being discharged from the absorption tower. It also includes a Johnson net, which is arranged at the outlet of the condenser and is used for primary defoaming and sedimentation of the condensed tail gas; It also includes a baffle, which is arranged at the inlet of the gas-liquid separation tank and is used to remove foam and settle the condensed tail gas again; It also includes a demister, which is arranged on the top of the gas-liquid separation tank and is used to demister and settle the condensed tail gas again.

2. The device for recovering silane from tail gas according to claim 1, characterized in that: The demister is a wire mesh demister.

3. The device for recovering silane from tail gas according to claim 1, characterized in that: After the absorption is completed, the absorption liquid discharged from the absorption tower is returned to the vaporization separation tower to decompose the silane.

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