CN113289468A - Treatment device for silicon tetrachloride tail gas - Google Patents
Treatment device for silicon tetrachloride tail gas Download PDFInfo
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- CN113289468A CN113289468A CN202010113131.6A CN202010113131A CN113289468A CN 113289468 A CN113289468 A CN 113289468A CN 202010113131 A CN202010113131 A CN 202010113131A CN 113289468 A CN113289468 A CN 113289468A
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- reactor
- silicon tetrachloride
- tail gas
- hypochlorite
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/68—Halogens or halogen compounds
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/73—After-treatment of removed components
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/77—Liquid phase processes
- B01D53/78—Liquid phase processes with gas-liquid contact
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/96—Regeneration, reactivation or recycling of reactants
Abstract
The invention provides a treatment device for silicon tetrachloride tail gas. The processing device includes: the first reactor is used for reacting the silicon tetrachloride tail gas with excessive alkali liquor to obtain a first reaction product containing silicate and hypochlorite; the solid-liquid separator is communicated with the outlet of the first reactor and is used for carrying out solid-liquid separation on the first reaction product to obtain a separation liquid; the second reactor is communicated with the outlet of the solid-liquid separator and is used for enabling hypochlorite and a reducing agent to perform oxidation-reduction reaction and convert the hypochlorite into chlorine salt so as to obtain a second reaction product; and the acid-base neutralization device is communicated with the outlet of the second reactor and is used for mixing the acid liquor and the second reaction product to neutralize the excessive alkali liquor. When the device is used for treating the silicon tetrachloride tail gas, sodium sulfite and other reducing agents can be used for treating hypochlorite in the leached waste alkali liquor, so that the accumulation of chlorine generated by the hypochlorite in an acid environment at the lower part of equipment or a pipeline is avoided, and the potential safety hazard of production is reduced.
Description
Technical Field
The invention relates to the technical field of high-purity silicon tetrachloride, and particularly relates to a device for treating silicon tetrachloride tail gas.
Background
The optical fiber communication has the advantages of wide transmission frequency band, large communication capacity, long relay distance, strong confidentiality, good anti-interference performance, nonferrous metal material saving and the like, and is widely concerned by various countries. The high added value attribute of the high-purity silicon tetrachloride for the optical fiber is an important direction for reducing the enterprise cost and expanding the profit growth point of enterprises for polysilicon production enterprises.
In the production process of high-purity silicon tetrachloride for optical fibers, hydroxyl group impurities which seriously affect the product quality can be removed only by a method of performing reactive distillation on the silicon tetrachloride. The silicon tetrachloride and the chlorine react in the photoreactor, then enter a separation tower for purification and separation, the generated tail gas is leached by saturated sodium hydroxide solution, and the leached waste liquid directly enters a three-waste treatment station of a polycrystalline silicon production system for neutralization treatment.
However, chlorine gas reacts with sodium hydroxide solution to generate sodium hypochlorite solution, if sodium hypochlorite is not treated and is directly discharged into a three-waste treatment system of a polysilicon system, the sodium hypochlorite reacts reversely in an acid environment of the three-waste treatment system to generate chlorine gas, and the chlorine gas is gathered at the lower part of equipment or a pipeline. Thereby generating potential safety production hazards.
Disclosure of Invention
The invention mainly aims to provide a treatment device of silicon tetrachloride tail gas, which aims to solve the problem that potential safety production hazards are easy to generate in a treatment device of the silicon tetrachloride tail gas in the prior art.
In order to achieve the above object, according to one aspect of the present invention, there is provided a treatment apparatus for silicon tetrachloride off-gas, the silicon tetrachloride off-gas containing chlorine gas, the treatment apparatus comprising: the first reactor is used for reacting the silicon tetrachloride tail gas with excessive alkali liquor to obtain a first reaction product containing silicate and hypochlorite; the solid-liquid separator is communicated with the outlet of the first reactor and is used for carrying out solid-liquid separation on the first reaction product to obtain a separation liquid; the second reactor is communicated with the outlet of the solid-liquid separator and is used for enabling hypochlorite and a reducing agent to perform oxidation-reduction reaction and convert the hypochlorite into chlorine salt so as to obtain a second reaction product; and the acid-base neutralization device is communicated with the outlet of the second reactor and is used for mixing the acid liquor and the second reaction product to neutralize the excessive alkali liquor.
Further, the first reactor is a spray tower, and the alkali liquor is used for leaching the silicon tetrachloride tail gas in the spray tower.
Furthermore, the spray tower is made of glass fiber reinforced plastic.
Further, pall ring packing is arranged in the spray tower.
Further, the first reactor is provided with a first inlet and a second inlet, the first inlet is used for introducing silicon tetrachloride tail gas, the second inlet is used for introducing alkali liquor, the treatment device further comprises an alkali liquor storage tank, and the alkali liquor storage tank is communicated with the second inlet.
Furthermore, the alkali liquor storage tank is provided with a return port, and the treatment device further comprises a return pipeline which is respectively communicated with the outlet and the return port of the second reactor.
Further, the treatment device also comprises a circulating pump which is arranged on the return pipeline.
Further, the circulation pump is a centrifugal pump.
Further, the second reactor is a static mixer.
Further, the solid-liquid separator has a first liner, and the first liner is polytetrafluoroethylene.
According to the technical scheme, the device for treating the silicon tetrachloride tail gas is provided, the silicon tetrachloride tail gas and alkali liquor can be mixed by a first reactor in the device and react to obtain a first reaction product containing silicate, hypochlorite and part of the alkali liquor, the silicate in the first reaction product is separated by a solid-liquid separator, then the separation liquid is mixed with a reducing agent by a second reactor and undergoes an oxidation-reduction reaction to obtain a second reaction product containing an oxidation product, a reduction product and part of the alkali liquor, the reduction product is chlorine salt, and then the second reaction product is neutralized by an acid-base neutralization device. When the device is used for treating the silicon tetrachloride tail gas, sodium sulfite and other reducing agents can be used for treating hypochlorite in the leached waste alkali liquor, so that the accumulation of chlorine generated by the hypochlorite in an acid environment at the lower part of equipment or a pipeline is avoided, and the potential safety hazard of production is reduced.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 shows a schematic structural diagram of a treatment device for silicon tetrachloride tail gas according to an embodiment of the invention.
Wherein the figures include the following reference numerals:
10. a first reactor; 20. a solid-liquid separator; 30. a second reactor; 40. an acid-base neutralization device; 50. an alkali liquor storage tank; 60. a return line; 70. and a circulating pump.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged under appropriate circumstances in order to facilitate the description of the embodiments of the invention herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
As described in the background art, chlorine gas reacts with sodium hydroxide solution to generate sodium hypochlorite solution, if sodium hypochlorite is not treated and is directly discharged into a three-waste treatment system of a polycrystalline silicon system, the sodium hypochlorite reacts reversely in an acid environment of the three-waste treatment system to generate chlorine gas, and the chlorine gas is gathered at the lower part of equipment or a pipeline. Thereby generating potential safety production hazards.
In order to solve the technical problems, the applicant of the present invention provides a treatment apparatus for silicon tetrachloride tail gas, the silicon tetrachloride tail gas comprises chlorine gas, as shown in fig. 1, the treatment apparatus comprises a first reactor 10, a solid-liquid separator 20, a second reactor 30 and an acid-base neutralization device 40, wherein the first reactor 10 is used for reacting the silicon tetrachloride tail gas with an excess alkali liquor to obtain a first reaction product containing silicate and hypochlorite; the solid-liquid separator 20 is communicated with an outlet of the first reactor 10, and is used for performing solid-liquid separation on the first reaction product to obtain a separation liquid; the second reactor 30 is communicated with the outlet of the solid-liquid separator 20 and is used for mixing the separated liquid with a reducing agent and enabling hypochlorite in the separated liquid to undergo an oxidation-reduction reaction and be converted into chlorine salt so as to obtain a second reaction product; an acid-base neutralization device 40 is in communication with the outlet of the second reactor 30 for mixing the acid solution with the second reaction product to neutralize excess alkali solution.
When the device is used for treating the silicon tetrachloride tail gas, sodium sulfite and other reducing agents can be used for treating hypochlorite in the leached waste alkali liquor, so that the accumulation of chlorine generated by the hypochlorite in an acid environment at the lower part of equipment or a pipeline is avoided, and the potential safety hazard of production is reduced.
In the treatment device, silicon tetrachloride tail gas and excess alkali liquor react in a first reactor 10 to obtain a first reaction product containing silicate and hypochlorite, wherein the silicon tetrachloride tail gas is generated in a production process of high-purity silicon tetrachloride for optical fibers and generally comprises silicon tetrachloride tail gas and chlorine; chlorosilane in the silicon tetrachloride tail gas mainly comprises silicon tetrachloride and alkali liquor which can generate silicate and is suspended in liquid, and the excessive alkali liquor is adopted to ensure that the alkali liquor can react with chlorine in the silicon tetrachloride tail gas to fully react to form hypochlorite while reacting with the silicon tetrachloride to generate the silicate, so that the chlorine in the tail gas can be removed more effectively.
Preferably, the first reactor 10 is an elution tower, and excess alkali liquor is contacted with the silicon tetrachloride tail gas in an elution mode, so that the silicon tetrachloride tail gas and the excess alkali liquor can be fully mixed; moreover, pall ring packing is arranged in the spray tower. More preferably, the spray tower is made of glass fiber reinforced plastics, the leacheate is in a strong acid and strong alkali environment, and the spray tower made of glass fiber reinforced plastics is adopted, so that the acid and alkali resistance can be improved.
Preferably, the first reactor 10 has a first inlet and a second inlet, the first inlet is used for introducing silicon tetrachloride tail gas, and the second inlet is used for introducing alkali liquor; as shown in FIG. 1, the above-mentioned treating apparatus of the present invention further comprises a lye storage tank 50, wherein the lye storage tank 50 is communicated with the second inlet for feeding lye into the first reactor 10.
Taking the excessive alkali liquor as the sodium hydroxide aqueous solution as an example, explaining the process performed in the rinsing tower, introducing the silicon tetrachloride tail gas into the rinsing tower, taking the sodium hydroxide aqueous solution as a rinsing liquid, mixing the sodium hydroxide aqueous solution with the sodium hydroxide aqueous solution in the rinsing tower, and then performing a chemical reaction, wherein the silicon tetrachloride reacts with the sodium hydroxide aqueous solution to form sodium silicate, and simultaneously, chlorine in the silicon tetrachloride tail gas reacts with the sodium hydroxide aqueous solution to form sodium hypochlorite.
It should be noted that the kind of the excess alkali solution used in the first reactor 10 is not limited to the above-mentioned aqueous sodium hydroxide solution, and those skilled in the art can make reasonable selection according to the prior art as long as the alkali solution can react with the silicon tetrachloride tail gas to effectively remove chlorine in the tail gas by forming silicate and hypochlorite.
Since chlorosilane in the silicon tetrachloride tail gas in the first reactor 10 is mainly silicate generated from silicon tetrachloride and alkali liquor and is suspended in liquid, the solid-liquid separator 20 in the treatment device of the invention is used for performing solid-liquid separation on the first reaction product, so that suspended solid silicate can be removed, and the solid-liquid separator 20 can be a suspension separator.
If the sodium hypochlorite formed in the first reactor 10 is directly neutralized with the acid liquor in the acid-base neutralization device 40, the sodium hypochlorite can generate a reverse reaction in an acid environment to generate chlorine, and the chlorine can be gathered at the lower part of equipment or a pipeline, so that potential safety production hazards are generated. In order to solve the above problems, the above treatment apparatus of the present invention is further provided with a second reactor 30, the first reaction product is subjected to solid-liquid separation in the above solid-liquid separator 20 to obtain a separated liquid, the separated liquid enters the second reactor 30 to be mixed with a reducing agent, wherein hypochlorite and the reducing agent undergo a redox reaction to be converted into a chloride salt, thereby obtaining a second reaction product.
Preferably, the second reactor 30 is a static mixer. In order to avoid corrosion of the mixer by strong acid and alkali environment and prolong the service life of the equipment, the static mixer is more preferably provided with a first lining which is polytetrafluoroethylene.
When the excess alkali liquor is an aqueous sodium hydroxide solution, taking a reducing agent as sodium sulfite as an example, explaining a process performed in the suspension separator and the static mixer, reacting the silicon tetrachloride tail gas with the aqueous sodium hydroxide solution in a spray tower to obtain a first reaction product containing sodium silicate and sodium hypochlorite, separating the sodium silicate in the first reaction product as a suspended matter in the suspension separator, and then taking out the suspended matter from the bottom, wherein the separated liquid can be filtered again through a filter not shown in the figure and then mixed with a saturated solution of sodium sulfite in the static mixer, and the sodium sulfite and the sodium hypochlorite simultaneously undergo an oxidation-reduction reaction in the static mixer to generate stable sodium sulfate and sodium chloride, and the reaction formula is as follows:
NaClO+Na2SO3→Na2SO4+NaCl
it should be noted that the kind of the reducing agent used in the second reactor 30 is not limited to the above sodium sulfite, and those skilled in the art can reasonably select the kind of the reducing agent according to the kind of the above excess alkali liquor, as long as the reducing agent can perform a redox reaction with hypochlorite to convert the reducing agent into a chloride salt.
Preferably, the treatment apparatus of the present invention further comprises a return line 60, as shown in fig. 1, wherein a return port is provided on the lye storage tank 50, such that the return line 60 is respectively communicated with the outlet of the second reactor 30 and the return port. The second reaction product obtained in the second reactor 30 still contains part of the alkali liquor due to the excessive amount of the alkali liquor adopted in the first reactor 10, and the part of the alkali liquor can be returned to the alkali liquor storage tank 50 through the backflow pipeline 60, so that the part of the alkali liquor and the original alkali liquor in the alkali liquor enter the first reactor 10 together to be mixed with the silicon tetrachloride tail gas, and the full utilization of the alkali liquor is realized; meanwhile, the liquid level of the alkali liquor storage tank 50 can be maintained, so that stable liquid supply to the first reactor 10 can be realized.
More preferably, the treatment apparatus of the present invention further comprises a circulation pump 70, and the circulation pump 70 is disposed on the return line 60, as shown in fig. 1. The second reaction product containing part of the alkali solution in the second reactor 30 can be transferred to the alkali solution storage tank 50 by the above-mentioned circulation pump 70, and the above-mentioned circulation pump 70 can be a centrifugal pump in order to improve the transfer efficiency.
In the above acid-base neutralization device 40 of the present invention, the acid solution is mixed with the second reaction product to neutralize the excess alkali solution, resulting in the treatment liquid. The acid-base neutralization device 40 is adopted to neutralize redundant alkali liquor in the second reaction product, so that the influence on the environment caused by the discharged treatment liquid is reduced. The skilled person can select the type of the acid solution according to the type of the excess alkali solution.
From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:
when the device is used for treating the silicon tetrachloride tail gas, sodium sulfite and other reducing agents can be used for treating hypochlorite in the leached waste alkali liquor, so that the accumulation of chlorine generated by the hypochlorite in an acid environment at the lower part of equipment or a pipeline is avoided, and the potential safety hazard of production is reduced.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A processing apparatus of silicon tetrachloride tail gas, silicon tetrachloride tail gas contains chlorine, its characterized in that, processing apparatus includes:
the first reactor (10) is used for reacting the silicon tetrachloride tail gas with excessive alkali liquor to obtain a first reaction product containing silicate and hypochlorite;
a solid-liquid separator (20) in communication with the outlet of the first reactor (10) for solid-liquid separation of the first reaction product to obtain a separated liquid;
a second reactor (30) communicated with the outlet of the solid-liquid separator (20) and used for enabling the hypochlorite and the reducing agent to perform oxidation-reduction reaction and be converted into chlorine salt so as to obtain a second reaction product;
an acid-base neutralization device (40) in communication with the outlet of the second reactor (30) for mixing an acid solution with the second reaction product to neutralize excess alkali solution.
2. The treatment apparatus according to claim 1, wherein the first reactor (10) is a spray tower in which the alkali liquor is used for rinsing the silicon tetrachloride off-gas.
3. The processing apparatus of claim 2, wherein the spray tower is a fiberglass material.
4. The processing apparatus according to claim 2, wherein pall ring packing is provided in the spray tower.
5. The treatment apparatus according to claim 2, wherein the first reactor (10) has a first inlet for introducing the silicon tetrachloride off-gas and a second inlet for introducing the lye, the treatment apparatus further comprising a lye storage tank (50), the lye storage tank (50) being in communication with the second inlet.
6. The processing apparatus according to claim 5, wherein the lye storage tank (50) is provided with a return port, the processing apparatus further comprising a return line (60), the return line (60) being in communication with the outlet of the second reactor (30) and the return port, respectively.
7. The processing apparatus according to claim 6, further comprising a circulation pump (70), the circulation pump (70) being arranged on the return line (60).
8. Treatment device according to claim 7, characterized in that the circulation pump (70) is a centrifugal pump.
9. The treatment plant according to any one of claims 1 to 8, wherein the second reactor (30) is a static mixer.
10. The processing unit according to any of claims 1 to 8, characterized in that the solid-liquid separator (20) has a first lining, which is polytetrafluoroethylene.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010113131.6A CN113289468A (en) | 2020-02-24 | 2020-02-24 | Treatment device for silicon tetrachloride tail gas |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010113131.6A CN113289468A (en) | 2020-02-24 | 2020-02-24 | Treatment device for silicon tetrachloride tail gas |
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| CN113289468A true CN113289468A (en) | 2021-08-24 |
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| CN202010113131.6A Pending CN113289468A (en) | 2020-02-24 | 2020-02-24 | Treatment device for silicon tetrachloride tail gas |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116332189A (en) * | 2023-03-30 | 2023-06-27 | 北京市弘洁蓝天科技股份有限公司 | Silicon tetrachloride disposal method and system |
-
2020
- 2020-02-24 CN CN202010113131.6A patent/CN113289468A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116332189A (en) * | 2023-03-30 | 2023-06-27 | 北京市弘洁蓝天科技股份有限公司 | Silicon tetrachloride disposal method and system |
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