Polycrystalline silicon reduction tail gas recovery device and system

Abstract

The utility model relates to the technical field of tail gas recovery, in particular to a polycrystalline silicon reduction tail gas recovery device and system, which comprises a heat exchanger positioned in front of a condensation section. The temperature of the reduction tail gas is 100-120 DEG C, the reduction tail gas enters the condensation section to be condensed after being cooled by the heat exchanger, the temperature of the reduction tail gas after heat exchange is reduced to about 65 DEG C, and most heat can be recycled. And the heat exchanger is arranged in front of the condensation section, so that heat in reduction tail gas can be recycled, and the effect of reducing the system cooling capacity is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to tail gas recovery technical field, concretely relates to a kind of polysilicon reduction tail gas recovery device and system. BACKGROUND

[0002] In traditional polysilicon production, hydrogen, hydrogen chloride, chlorosilane mixed gas from reduction furnace is 100-120 ℃ when entering tail gas recovery process, in order to separate hydrogen and chlorosilane gas in tail gas, realize the recovery of hydrogen and the recovery of chlorosilane, usually need to cool the reduction tail gas step by step to condense chlorosilane in tail gas, so as to be recovered, a lot of cold energy will be consumed in this process.

[0003] In tail gas recovery traditional process, high pressure area is absorption and analysis system, in absorption tower absorption process, -50 ℃ low temperature chlorosilane is needed to be used to wash tail gas to remove hydrogen chloride and chlorosilane in it, after washing, low temperature high pressure chlorosilane liquid rich in hydrogen chloride needs to be heated by multi-stage heat exchange and then enters hydrogen chloride analysis tower to remove chlorosilane, hydrogen chloride and chlorosilane low boiling point substance and a small amount of hydrogen gas adsorbed in chlorosilane, low temperature high pressure chlorosilane liquid in absorption tower needs to be heated and sent into analysis tower for analysis before entering analysis tower, although multi-stage heat exchanger is used for multi-stage heat exchange, but a lot of heat is still consumed, which leads to low comprehensive energy utilization rate of the whole system. UTILITARIAN CONTENT

[0004] The utility model aims at providing a kind of polysilicon reduction tail gas recovery device and system, solve the technical problem of low comprehensive energy utilization rate of system in prior art.

[0005] The utility model discloses a kind of polysilicon reduction tail gas recovery device, including heat exchanger, the heat exchanger is located before condensation section.

[0006] Working principle: reduction tail gas temperature is 100-120 ℃, heat exchanger enters condensation section after reducing the temperature of reduction tail gas, the temperature of reduction tail gas after heat exchange drops to about 65 ℃, most of the heat can be recovered. By setting heat exchanger before condensation section, the heat recovery in reduction tail gas can be realized, and the effect of system cold quantity is reduced.

[0007] Further, the heat exchanger is connected with absorption tower and analysis tower.

[0008] By setting absorption tower, the rich liquid extracted from absorption tower kettle is first heat exchanged by heat exchanger, heat exchanger converts the heat in reduction tail gas into rich liquid, reduces the temperature of reduction tail gas, and increases the temperature of rich liquid, which saves a lot of energy.

[0009] By setting the analysis tower, the rich liquid is heated and then enters the analysis tower, which saves the steam consumed by the analysis tower and reduces the use of energy.

[0010] Further, the analysis tower is connected with a reboiler.

[0011] By setting the reboiler, the analysis tower is provided with rising heating steam, and the hydrogen chloride in the rich liquid entering the analysis tower can be resolved.

[0012] Further, the absorption tower is connected with the analysis tower.

[0013] By connecting the absorption tower with the analysis tower, the rich liquid after heat exchange enters the analysis tower to remove the hydrogen chloride, chlorosilane low-boiling substances and a small amount of hydrogen gas adsorbed in the chlorosilane, and the obtained lean liquid enters the absorption tower.

[0014] Further, a preheater is arranged between the absorption tower and the analysis tower.

[0015] By setting the preheater, the lean liquid discharged from the analysis tower can be first heat-exchanged with the rich liquid discharged from the absorption tower to increase the temperature of the rich liquid.

[0016] Further, the condensation section is connected with the absorption tower.

[0017] By connecting the condensation section with the absorption tower, the non-condensable gas separated from the condensation section enters the absorption tower, and the chlorosilane therein is condensed into liquid and separated from hydrogen gas.

[0018] Further, the absorption tower discharges rich liquid from the lower part and enters lean liquid from the upper part.

[0019] By discharging rich liquid from the lower part of the absorption tower and entering lean liquid from the upper part, it can be ensured that the hydrogen chloride in the hydrogen gas is completely absorbed, and the product hydrogen gas is relatively pure.

[0020] Further, the lower part of one side of the heat exchanger enters the rich liquid, and the upper part of the other side of the heat exchanger discharges the rich liquid.

[0021] By entering the rich liquid from the lower part of one side of the heat exchanger and discharging the rich liquid from the upper part of the other side of the heat exchanger, it can be ensured that the rich liquid has sufficient heat exchange path in the heat exchanger, and better heat exchange effect can be achieved.

[0022] A polysilicon reduction tail gas recovery system comprises a heat exchanger, the heat exchanger is connected with an absorption tower and an analysis tower,

[0023] Further, a preheater is arranged between the absorption tower and the analysis tower.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] 1. By setting heat exchanger before condensing section, heat recovery in the reduction tail gas can be realized, the effect of reducing system cold is reduced;

[0026] 2. By setting absorption tower, the rich liquid collected from the tower kettle of absorption tower is first exchanged by heat exchanger, the heat exchanger converts the heat in the reduction tail gas to the rich liquid, reduces the temperature of the reduction tail gas, and increases the temperature of the rich liquid, saves a large amount of energy;

[0027] 3. By setting the resolution tower, the rich liquid is heated and then enters the resolution tower, saving the steam consumed by the resolution tower, reducing the use of energy;

[0028] 4. By setting the reboiler, the resolution tower provides rising heating steam, which can resolve hydrogen chloride in the rich liquid entering the resolution tower;

[0029] 5. By connecting the absorption tower with the resolution tower, the rich liquid after heat exchange enters the resolution tower to remove the adsorbed hydrogen chloride, chlorosilane low boiling point substance and a small amount of hydrogen in chlorosilane, and the obtained lean liquid enters the absorption tower;

[0030] 6. By setting the preheater, the lean liquid discharged from the resolution tower is first exchanged with the rich liquid discharged from the absorption tower, and the temperature of the rich liquid is increased;

[0031] 7. By connecting the condensing section with the absorption tower, the non-condensable gas separated from the condensing section enters the absorption tower, and the chlorosilane therein is condensed into liquid and separated from hydrogen;

[0032] 8. By discharging the rich liquid from the lower part of the absorption tower and entering the lean liquid from the upper part, the hydrogen chloride in the hydrogen gas can be completely absorbed, and the product hydrogen gas can be obtained;

[0033] 9. By entering the rich liquid from the lower part of one side of the heat exchanger and discharging the rich liquid from the upper part of the other side, the rich liquid can have sufficient heat exchange path in the heat exchanger, and better heat exchange effect can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only represent some embodiments of the present application, and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained without creative labor on the basis of these drawings.

[0035] Figure 1 The structure diagram of the polycrystalline silicon reduction tail gas recovery device of the present application.

[0036] In the above figures, the meaning of each mark is as follows: 1 - heat exchanger, 2 - condensing section, 3 - absorption tower, 4 - desorption tower, 5 - reboiler, 6 - preheater. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all embodiments of the present application.

[0038] Embodiment 1

[0039] The technical scheme adopted in this embodiment is as follows:

[0040] As shown in Figure 1 A polysilicon reduction tail gas recovery device and system, comprising a heat exchanger 1, the heat exchanger 1 is located in front of the condensing section 2.

[0041] Working principle: the temperature of the reduction tail gas is 100-120℃, the heat exchanger 1 reduces the temperature of the reduction tail gas before entering the condensing section 2 for condensation, and the temperature of the reduction tail gas after heat exchange drops to about 65℃, so that most of the heat can be recovered. By setting the heat exchanger 1 in front of the condensing section 2, heat recovery in the reduction tail gas can be achieved, and the effect of reducing the system cold quantity is reduced.

[0042] Embodiment 2

[0043] In this embodiment as a preferred embodiment of the present application, the specific structure is as shown in Figure 1 Based on the embodiment 1, the following improvements are disclosed, the heat exchanger 1 is connected with the absorption tower 3 and the desorption tower 4.

[0044] By setting the absorption tower 3, the rich liquid collected from the tower kettle of the absorption tower 3 is first subjected to heat exchange in the heat exchanger 1, the heat exchanger 1 converts the heat in the reduction tail gas to the rich liquid, reduces the temperature of the reduction tail gas, and increases the temperature of the rich liquid, thereby saving a large amount of energy.

[0045] By setting the desorption tower 4, the rich liquid is heated before entering the desorption tower 4, thereby saving the steam consumed by the desorption tower 4 and reducing the use of energy.

[0046] Embodiment 3

[0047] In this embodiment as a preferred embodiment of the present application, the specific structure is as shown in Figure 1 Based on the embodiment 2, the following improvements are disclosed, the desorption tower 4 is connected with the reboiler 5.

[0048] By setting the reboiler 5, the hydrogen chloride in the rich liquid entering the resolving column 4 is resolved.

[0049] Embodiment 4

[0050] In the embodiment as a preferred embodiment of the utility model, the specific structure is as shown in Figure 1 The absorption tower 3 is connected with the resolving column 4.

[0051] By connecting the absorption tower 3 with the resolving column 4, the rich liquid after heat exchange enters the resolving column 4 to remove the hydrogen chloride, chlorosilane low-boiling substance and a small amount of hydrogen gas adsorbed in the chlorosilane, and the obtained lean liquid enters the absorption tower 3.

[0052] Embodiment 5

[0053] In the embodiment as a preferred embodiment of the utility model, the specific structure is as shown in Figure 1 The preheater 6 is arranged between the absorption tower 3 and the resolving column 4.

[0054] By arranging the preheater 6, the lean liquid discharged from the resolving column 4 can be first heat-exchanged with the rich liquid discharged from the absorption tower 3, so that the temperature of the rich liquid is improved.

[0055] Embodiment 6

[0056] In the embodiment as a preferred embodiment of the utility model, the specific structure is as shown in Figure 1 The condensing section 2 is connected with the absorption tower 3.

[0057] By connecting the condensing section 2 with the absorption tower 3, the non-condensable gas separated from the condensing section 2 enters the absorption tower 3, and the chlorosilane therein is condensed into liquid and separated from the hydrogen gas.

[0058] Embodiment 7

[0059] In the embodiment as a preferred embodiment of the utility model, the specific structure is as shown in Figure 1 The rich liquid is discharged from the lower part of the absorption tower 3, and the lean liquid enters the upper part.

[0060] By discharging the rich liquid from the lower part of the absorption tower 3 and making the lean liquid enter the upper part, it can be ensured that the hydrogen chloride in the hydrogen gas is completely absorbed, and the product hydrogen gas is relatively pure.

[0061] Embodiment 8

[0062] In the embodiment as a preferred embodiment of the utility model, the specific structure is as shown in Figure 1As shown, it discloses the following improvement on the basis of embodiment 7, the lower part of one side of the heat exchanger 1 enters rich liquid, and the upper part of the other side discharges rich liquid.

[0063] By entering rich liquid through the lower part of one side of the heat exchanger 1 and discharging rich liquid through the upper part of the other side, it can ensure that the rich liquid has sufficient heat exchange path in the heat exchanger 1, and achieve better heat exchange effect.

[0064] The above is the embodiment of the enumerated embodiments, but the embodiment is not limited to the above optional embodiments, and those skilled in the art can obtain other various embodiments by arbitrarily combining the above-mentioned modes with each other. Any person can derive other various forms of embodiments under the inspiration of the embodiment. The above specific embodiments should not be understood as limiting the protection scope of the embodiment, and the protection scope of the embodiment should be defined by the claims, and the specification can be used to explain the claims.

Claims

1. A polysilicon reduction tail gas recovery apparatus, characterized by: The application relates to a heat exchanger (1) located in front of a condensing section (2), wherein an absorption tower (3) and a desorption tower (4) are connected to the heat exchanger (1), the desorption tower (4) is connected with a reboiler (5), and the absorption tower (3) is connected with the desorption tower (4).

2. A polysilicon reduction tail gas recovery apparatus according to claim 1, characterized in that: A preheater (6) is arranged between the absorption tower (3) and the desorption tower (4).

3. A polysilicon reduction tail gas recovery apparatus as claimed in claim 1, wherein: The condensing section (2) is connected with the absorption tower (3).

4. The apparatus of claim 1, wherein: Rich liquid is discharged from the lower part of the absorption tower (3) and lean liquid is introduced into the upper part of the absorption tower (3).

5. A polysilicon reduction tail gas recovery apparatus as claimed in claim 1, wherein: Rich liquid is introduced into the lower part of one side of the heat exchanger (1) and lean liquid is discharged from the upper part of the other side of the heat exchanger (1).

6. A polysilicon reduction tail gas recovery system characterized by: The application further relates to a device for recovering the tail gas of a polysilicon reduction process, which comprises the heat exchanger (1) according to any one of claims 1-5.

Images