Recovery method and recovery device for hydrogen in electronic-grade polycrystalline silicon reduction tail gas

Abstract

The invention relates to the field of polycrystalline silicon tail gas recovery, in particular to a method and a device for recovering hydrogen in electronic-grade polycrystalline silicon reduction tail gas. The recovery method comprises the following steps: mixing a porous adsorption material and a chemical absorbent to obtain a mixture; the method comprises the following steps: contacting electronic-grade polycrystalline silicon reduction tail gas with a mixture to remove impurities in the electronic-grade polycrystalline silicon reduction tail gas so as to obtain mixed gas, filtering and compressing the mixed gas so as to obtain high-purity hydrogen, and using the high-purity hydrogen as a raw material for preparing electronic-grade polycrystalline silicon, wherein the electronic-grade polycrystalline silicon reduction tail gas is composed of hydrogen and impurities; the content of the hydrogen is greater than or equal to 99.9%; the chemical absorbent comprises an active component and a solvent; the active component comprises at least one of triphenylchloromethane and diphenyl carbazone. According to the recycling method, physical and chemical dual adsorption is adopted, the effect is better, hydrogen waste caused by saturated purging regeneration of the porous adsorption material can be avoided by adding the chemical absorbent, and therefore resources are saved.

Description

Technical Field

[0001] The invention relates to the field of polysilicon tail gas recovery, and in particular to a method for recovering hydrogen in electronic-grade polysilicon reduction tail gas and a recovery device thereof. Background Art

[0002] The modified Siemens process is the main method for preparing electronic-grade polysilicon. During the reduction stage, it produces complex tail gas containing trichlorosilane, silicon tetrachloride, dichlorosilane, hydrogen, hydrogen chloride, and trace impurities such as P and B. Although the purification of existing tail gas recovery technology is relatively mature, the efficient purification technology for hydrogen in tail gas is still insufficient.

[0003] Common hydrogen purification technologies include cryogenic or adsorption technologies. Due to its limited purification effect and high energy consumption, cryogenic purification technology is only applicable to the production of photovoltaic-grade polysilicon products and cannot meet the preparation of electronic-grade polysilicon with higher purity requirements. Although activated carbon adsorption can achieve physical purification of hydrogen, the adsorption saturation characteristics of activated carbon require regular use of hydrogen for purging and regeneration, which not only increases operating costs but also brings challenges to hydrogen treatment.

[0004] The treatment of hydrogen used in the current purge regeneration of the adsorbent is not mentioned. The purge hydrogen carries a large amount of trace impurities such as phosphorus and boron. If it returns to the system, the impurities it carries will also return to the system, ultimately affecting the product quality. At the same time, the total amount of hydrogen used in the activated carbon regeneration process is considerable. Direct discharge not only wastes resources, but also increases production costs. Therefore, it is urgent to provide an efficient, simple, and resource-saving method for recovering hydrogen from the reduced tail gas. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the present invention provides a method for recovering hydrogen from electronic-grade polysilicon reduction tail gas and a recovery device thereof. The present invention adopts physical and chemical dual adsorption to achieve a better adsorption effect, so that the boron and phosphorus impurities contained therein are reduced to the ppt level (one trillionth), and high-purity hydrogen is obtained. In addition, the addition of a chemical absorbent can avoid the waste of hydrogen caused by the saturated purge regeneration of the porous adsorption material when the porous adsorption material is used alone, thereby saving resources and reducing costs.

[0006] To this end, the first aspect of the present invention provides a method for recovering hydrogen from electronic-grade polysilicon reduction tail gas, comprising the following steps:

[0007] mixing a porous adsorbent material and a chemical absorbent to obtain a mixture;

[0008] contacting the electronic-grade polysilicon reduction tail gas with the mixture to remove impurities in the electronic-grade polysilicon reduction tail gas to obtain a mixed gas, filtering and compressing the mixed gas to obtain high-purity hydrogen, and the high-purity hydrogen is used to prepare a raw material for electronic-grade polysilicon;

[0009] Wherein, the electronic-grade polysilicon reduction tail gas is composed of hydrogen and impurities;

[0010] The hydrogen content is ≥99.9%;

[0011] The chemical absorbent includes an active ingredient and a solvent;

[0012] The active ingredient includes at least one of triphenylmethane and diphenylcarbazone.

[0013] The method for recovering hydrogen from the tail gas of electronic-grade polysilicon reduction provided by the present invention adopts physical and chemical dual adsorption, has a better adsorption effect, can obtain high-purity hydrogen, and has an extremely low impurity content, which can be directly used as a raw material for the production of electronic-grade polysilicon, thereby realizing resource recycling. In addition, compared with the traditional activated carbon adsorption method, the addition of the chemical absorbent in the present invention can avoid the complicated process of periodically using hydrogen for purging and regeneration due to the saturation of the porous adsorption material, thereby reducing the waste of resources and environmental burden caused by the waste of hydrogen.

[0014] According to an embodiment of the present invention, the chemical absorbent includes triphenylmethane chloride and diphenylcarbazone; the mass ratio of triphenylmethane chloride to diphenylcarbazone is 1:(0.5-2).

[0015] According to an embodiment of the present invention, the mass ratio of the chemical absorbent to the porous adsorption material is 0.8-2.

[0016] According to an embodiment of the present invention, the porous adsorption material includes at least one of activated carbon and molecular sieve.

[0017] According to an embodiment of the present invention, the particle size of the porous adsorption material is 325 mesh-800 mesh.

[0018] According to an embodiment of the present invention, the solvent includes benzene.

[0019] According to an embodiment of the present invention, the concentration of the active ingredient in the solvent is 1.8 wt %-3.0 wt %.

[0020] According to an embodiment of the present invention, the contact temperature is 5°C-20°C.

[0021] According to an embodiment of the present invention, the impurities include P and B impurities.

[0022] A second aspect of the present invention provides a device for recovering hydrogen from tail gas of electronic-grade polysilicon reduction, the device comprising a first gas separation unit, a second gas separation unit, a buffer unit, and a compression unit connected in sequence;

[0023] Wherein, the first gas separation unit comprises a gas separation reactor, and the gas separation reactor is filled with a mixture comprising a porous adsorption material and a chemical absorbent;

[0024] The chemical absorbent comprises an active ingredient and a solvent; the active ingredient comprises at least one of triphenylmethane and diphenylcarbazone.

[0025] The recovery device provided by the present invention can realize the efficient recovery of hydrogen in the tail gas of electronic-grade polysilicon reduction, obtain high-purity hydrogen with extremely low impurity content, and can be directly used as the production raw material of electronic-grade polysilicon, thus realizing the recycling of resources. In addition, compared with the traditional activated carbon adsorption method, the addition of the chemical absorbent in the present invention can avoid the complicated process of periodically using hydrogen for purging and regeneration due to the saturation of the porous adsorption material, thereby reducing the waste of resources and environmental burden caused by the waste of hydrogen.

[0026] According to an embodiment of the present invention, the gas separation reactor is provided with:

[0027] a feed port for loading the chemical adsorbent into the gas separation reactor;

[0028] A discharge port, used to discharge liquid components in the mixture;

[0029] A gas inlet, used to provide electronic grade polysilicon reduction tail gas to the gas separation reactor;

[0030] The gas outlet is connected to the second gas separation unit.

[0031] According to an embodiment of the present invention, the feed port, the feed port, the air inlet and the air outlet are all provided with control valves.

[0032] According to an embodiment of the present invention, the first gas separation unit includes a plurality of the gas separation reactors, and each of the gas separation reactors is independently connected to the second gas separation unit.

[0033] According to an embodiment of the present invention, the pore size of the filter material in the second gas separation unit is ≥50 meshes.

[0034] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0036] Figure 1 The invention shows a device for recovering hydrogen from tail gas produced by reducing electronic-grade polysilicon.

[0037] Reference numerals:

[0038] A recovery device 10 , a first gas separation unit 100 , a first gas separation reactor 101 , a second gas separation reactor 102 , a second gas separation unit 200 , a buffer unit 300 , and a compression unit 400 . DETAILED DESCRIPTION

[0039] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0040] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0041] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0042] In order to make the present invention more easily understood, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined elsewhere in this document, all other technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which the present invention belongs.

[0043] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention but not excluding other contents.

[0044] As used herein, the terms "optionally", "optional" or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0045] According to an embodiment of the present invention, a first aspect of the present invention provides a method for recovering hydrogen from electronic-grade polysilicon reduction tail gas, comprising the following steps:

[0046] mixing a porous adsorbent material and a chemical absorbent to obtain a mixture;

[0047] contacting the electronic-grade polysilicon reduction tail gas with the mixture to remove impurities in the electronic-grade polysilicon reduction tail gas to obtain a mixed gas, filtering and compressing the mixed gas to obtain high-purity hydrogen, and the high-purity hydrogen is used to prepare a raw material for electronic-grade polysilicon;

[0048] Wherein, the electronic-grade polysilicon reduction tail gas is composed of hydrogen and impurities;

[0049] The hydrogen content is ≥99.9%;

[0050] The chemical absorbent includes an active ingredient and a solvent;

[0051] The active ingredient includes at least one of triphenylmethane and diphenylcarbazone.

[0052] In the present invention, the electronic-grade polysilicon reduction tail gas contains hydrogen and impurities (such as trace boron and phosphorus), that is, the reduction tail gas has been subjected to the removal of trichlorosilane, silicon tetrachloride, dichlorosilane, hydrogen chloride, etc. produced in the electronic-grade polysilicon reduction stage, and then high-purity hydrogen is obtained through the recovery method provided by the present invention, which can meet the preparation of electronic-grade polysilicon with higher requirements for hydrogen purity. The electronic-grade polysilicon reduction tail gas used in the present invention also contains a small amount of chlorosilane impurities, but chlorosilane can be used as a raw material when entering the reduction process, so there is no need to consider the chlorosilane content.

[0053] According to a specific embodiment of the present invention, the chemical absorbent includes triphenylmethane chloride and diphenylcarbazone; the mass ratio of triphenylmethane chloride and diphenylcarbazone is 1:(0.5-2). As some specific examples, the mass ratio of triphenylmethane chloride and diphenylcarbazone can be 1:0.5, 1:1, 1:1.5, 1:2, etc.

[0054] According to a specific embodiment of the present invention, the mass ratio of the chemical absorbent to the porous adsorption material is 0.8-2. As some specific examples, the mass ratio of the chemical absorbent to the porous adsorption material can be 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2.0, etc.

[0055] According to a specific embodiment of the present invention, the type of the porous adsorption material is not particularly limited. As some specific examples, the porous adsorption material includes at least one of activated carbon and molecular sieve.

[0056] According to a specific embodiment of the present invention, the particle size of the porous adsorption material is 325 mesh-800 mesh. As some specific examples, the particle size of the porous adsorption material may be 325 mesh, 400 mesh, 500 mesh, 600 mesh, 700 mesh, 800 mesh, etc.

[0057] According to a specific embodiment of the present invention, the type of the solvent is not particularly limited. As some specific examples, the solvent includes but is not limited to benzene.

[0058] According to a specific embodiment of the present invention, the concentration of the active ingredient in the solvent is 1.8wt%-3wt%. As some specific examples, the concentration of the active ingredient in the solvent may be 1.8wt%, 2.1wt%, 2.4wt%, 2.7wt%, 3wt% and the like.

[0059] According to a specific embodiment of the present invention, the contact temperature is 5°C-20°C. As some specific examples, the contact temperature may be 5°C, 7°C, 10°C, 13°C, 15°C, 20°C, etc.

[0060] According to a specific embodiment of the present invention, the type of the impurities is not particularly limited. As some specific examples, the impurities include P and B impurities.

[0061] According to an embodiment of the present invention, a second aspect of the present invention provides a device for recovering hydrogen from tail gas of electronic grade polysilicon reduction, see Figure 1 , the recovery device 10 includes a first gas separation unit 100, a second gas separation unit 200, a cache unit 300, and a compression unit 400 connected in sequence;

[0062] Wherein, the first gas separation unit 100 comprises a gas separation reactor, and the gas separation reactor is filled with a mixture comprising a porous adsorption material and a chemical absorbent;

[0063] The chemical absorbent comprises an active ingredient and a solvent; the active ingredient comprises at least one of triphenylmethane and diphenylcarbazone.

[0064] The porous adsorbent is initially immersed in the chemical absorbent. When the reduced tail gas enters the gas separation reactor, the airflow of the reduced tail gas sweeps the chemical absorbent into the pores of the porous adsorbent material in the entire gas separation reactor. On the one hand, the chemical absorbent can better react with phosphorus and boron impurities in the pores of the porous adsorbent material; on the other hand, the chemical absorbent can also remove impurities physically adsorbed by the porous adsorbent material. Physical and chemical dual adsorption can not only achieve a better adsorption effect, but also avoid the waste of hydrogen caused by purging and regeneration when the porous adsorbent material is saturated.

[0065] According to a specific embodiment of the present invention, the type of the gas separation reactor is not particularly limited. As some specific examples, the gas separation reactor includes but is not limited to an adsorption tower.

[0066] According to a specific embodiment of the present invention, the gas separation reactor is provided with:

[0067] a feed port for loading the chemical adsorbent into the gas separation reactor;

[0068] A discharge port, used to discharge liquid components in the mixture;

[0069] A gas inlet, used to provide electronic grade polysilicon reduction tail gas to the gas separation reactor;

[0070] The gas outlet is connected to the second gas separation unit.

[0071] According to a specific embodiment of the present invention, the feed port, the discharge port, the air inlet and the air outlet are all provided with control valves. Specifically, the feed port is provided with a first control valve, the discharge port is provided with a second control valve, the air inlet is provided with a third control valve, and the air outlet is provided with a fourth control valve. Before the reaction is carried out, a porous adsorption material is loaded into the gas separation reactor, the first control valve and the third control valve are opened, the chemical adsorbent is loaded into the gas separation reactor through the feed port, the electronic grade polysilicon reduction tail gas is provided into the gas separation reactor through the air inlet, the fourth control valve is opened, the electronic grade polysilicon reduction tail gas is discharged from the air outlet after adsorption, and enters the cache unit 300 after passing through the second gas separation unit 200. The hydrogen in the cache unit 300 is compressed by the compression unit 400 and enters the reduction system as a raw material for the production of electronic grade polysilicon. According to a specific embodiment of the present invention, the first gas separation unit 100 may include a plurality of the gas separation reactors, each of which is independently connected to the second gas separation unit 200. This allows one gas separation reactor to be used while the other gas separation reactors are used as backup. Figure 1 , including two gas separation reactors, namely a first gas separation reactor 101 and a second gas separation reactor 102.

[0072] According to a specific embodiment of the present invention, the method for recovering hydrogen from the tail gas of electronic-grade polysilicon reduction further comprises regularly replacing the chemical absorbent to Figure 1For example, the operation of regularly replacing the chemical absorbent may be specifically as follows: when replacing the chemical absorbent in the first gas separation reactor 101, the gas inlet valve and the gas outlet valve of the second gas separation reactor 102 are opened in sequence, and after a period of time, the gas outlet valve and the gas inlet valve of the first gas separation reactor 101 are closed, and the reducing tail gas enters from the gas inlet of the second gas separation reactor 102. After the first gas separation reactor 101 is left to stand for a period of time, since there is no reducing tail gas passing through the reactor, the liquid chemical absorbent in the first gas separation reactor 101 falls to the bottom of the reactor due to gravity, and the discharge port valve is opened, and the chemical absorbent is discharged from the discharge port valve of the first gas separation reactor 101. After the chemical absorbent is discharged, the discharge port valve is closed, the feed port valve is opened, and the newly prepared chemical absorbent is injected from the feed port valve. When replacing the chemical absorbent in the second gas separation reactor 102, refer to the process of the first gas separation reactor 101.

[0073] According to a specific embodiment of the present invention, a demister is disposed on the top of the gas separation reactor, which can reduce mist entrainment.

[0074] According to a specific embodiment of the present invention, the type of the second gas separation unit 200 is not particularly limited. As some specific examples, the second gas separation unit 200 includes but is not limited to a filter.

[0075] According to a specific embodiment of the present invention, the pore size of the filter material in the second gas separation unit 200 is ≥50 meshes.

[0076] According to a specific embodiment of the present invention, the type of the cache unit 300 is not particularly limited. As some specific examples, the cache unit 300 includes but is not limited to a hydrogen buffer device.

[0077] According to a specific embodiment of the present invention, the type of the compression unit 400 is not particularly limited. As some specific examples, the compression unit 400 includes but is not limited to a compressor.

[0078] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0079] Example 1

[0080] 3.6 kg of triphenylmethane was dissolved in benzene, wherein the concentration of triphenylmethane was 1.8 wt %, thereby obtaining a chemical absorbent. The chemical absorbent and 200 kg of activated carbon were loaded into an adsorption tower, and electronic-grade polysilicon reduction tail gas was introduced. The temperature in the adsorption tower was maintained at 7° C. The reduction tail gas was discharged from the top of the tower after adsorption, and entered a hydrogen buffer tank through a filter. The hydrogen in the buffer tank was compressed and entered the subsequent reduction stage of the electronic-grade polysilicon.

[0081] Example 2

[0082] 3.6 kg of diphenylcarbazone is dissolved in benzene, wherein the concentration of diphenylcarbazone is 1.8 wt %, thereby obtaining a chemical absorbent. The chemical absorbent and 200 kg of activated carbon are loaded into an adsorption tower, and electronic-grade polysilicon reduction tail gas is introduced. The temperature in the adsorption tower is maintained at 7° C. The reduction tail gas is discharged from the top of the tower after adsorption, and enters a hydrogen buffer tank through a filter. The hydrogen in the buffer tank is compressed and enters the subsequent reduction stage of the electronic-grade polysilicon.

[0083] Example 3

[0084] 1.2 kg of triphenylmethane and 2.4 kg of diphenylcarbazone are dissolved in benzene, wherein the mass ratio of triphenylmethane to diphenylcarbazone is 1:2, and the total concentration of triphenylmethane and diphenylcarbazone in the solvent is 1.8 wt%, thereby obtaining a chemical absorbent. The chemical absorbent and 200 kg of activated carbon are loaded into an adsorption tower, and electronic-grade polysilicon reduction tail gas is introduced. The temperature in the adsorption tower is maintained at 10°C, and the reduction tail gas is discharged from the top of the tower after adsorption, and enters a hydrogen buffer tank through a filter. The hydrogen in the buffer tank is compressed and enters the subsequent reduction stage of electronic-grade polysilicon.

[0085] Example 4

[0086] 2.1 kg of triphenylmethane and 2.1 kg of diphenylcarbazone are dissolved in benzene, wherein the mass ratio of triphenylmethane to diphenylcarbazone is 1:1, and the total concentration of triphenylmethane and diphenylcarbazone in the solvent is 2.1 wt%, thereby obtaining a chemical absorbent. The chemical absorbent and 200 kg of activated carbon are loaded into an adsorption tower, and electronic-grade polysilicon reduction tail gas is introduced. The temperature in the adsorption tower is maintained at 10°C, and the reduction tail gas is discharged from the top of the tower after adsorption, and enters a hydrogen buffer tank through a filter. The hydrogen in the buffer tank is compressed and enters the subsequent reduction stage of electronic-grade polysilicon.

[0087] Example 5

[0088] 2.4 kg of triphenylmethane and 1.2 kg of diphenylcarbazone are dissolved in benzene, wherein the mass ratio of triphenylmethane to diphenylcarbazone is 2:1, and the total concentration of triphenylmethane and diphenylcarbazone in the solvent is 1.8 wt%, thereby obtaining a chemical absorbent. The chemical absorbent and 200 kg of activated carbon are loaded into an adsorption tower, and electronic-grade polysilicon reduction tail gas is introduced. The temperature in the adsorption tower is maintained at 13° C. The reduction tail gas is discharged from the top of the tower after adsorption, and enters a hydrogen buffer tank through a filter. The hydrogen in the buffer tank is compressed and enters the subsequent reduction stage of electronic-grade polysilicon.

[0089] Comparative Example 1

[0090] 200 kg of activated carbon is loaded into the adsorption tower, and electronic-grade polysilicon reduction exhaust gas is introduced. The temperature in the adsorption tower is maintained at 7°C. The reduction exhaust gas is discharged from the top of the tower after adsorption and enters the hydrogen buffer tank through the filter. The hydrogen in the buffer tank is compressed and enters the subsequent reduction stage of electronic-grade polysilicon.

[0091] Comparative Example 2

[0092] 4.2 kg of triphenylmethane is dissolved in benzene, wherein the concentration of triphenylmethane is 2.1 wt %, thereby obtaining a chemical absorbent. The chemical absorbent is loaded into an adsorption tower, and the electronic-grade polysilicon reduction tail gas is introduced. The temperature in the adsorption tower is maintained at 7° C. The reduction tail gas is discharged from the top of the tower after adsorption, and enters a hydrogen buffer tank through a filter. The hydrogen in the buffer tank is compressed and enters the subsequent reduction stage of the electronic-grade polysilicon.

[0093] Comparative Example 3

[0094] 4.2 kg of diphenylcarbazone is dissolved in benzene, wherein the concentration of diphenylcarbazone is 2.1 wt %, thereby obtaining a chemical absorbent. The chemical absorbent is loaded into an adsorption tower, and electronic-grade polysilicon reduction tail gas is introduced. The temperature in the adsorption tower is maintained at 7° C. The reduction tail gas is discharged from the top of the tower after adsorption, and enters a hydrogen buffer tank through a filter. The hydrogen in the buffer tank is compressed and enters the subsequent reduction stage of the electronic-grade polysilicon.

[0095] The phosphorus content of normal electronic grade polysilicon products is an average of 16 ppta, and the boron content is an average of 3 ppta. The hydrogen recovered by the embodiments of the present invention and the comparative examples was passed into a small CVD evaluation furnace to verify the quality of the hydrogen product. The product data of the hydrogen recovered by the embodiments 1-5 and the comparative examples 1-3 are shown in Table 1:

[0096] Table 1

[0097] Sample No. P content (ppta) B content (ppta) Example 1 13.7 2.1 Example 2 13.8 1.9 Example 3 12.7 2.1 Example 4 12.1 1.7 Example 5 13.1 2.2 Comparative Example 1 24.5 8.5 Comparative Example 2 77.5 16.7 Comparative Example 3 74.3 18.5

[0098] It can be seen from the data in Table 1 that the contents of impurity P and impurity B in the hydrogen recovered in Examples 1-5 are significantly lower than the contents of impurity P and impurity B in the electronic-grade polysilicon product, indicating that the hydrogen obtained by the recovery method of the present invention has high purity and can be directly used as a raw material for the production of electronic-grade polysilicon, thereby realizing resource recycling and avoiding environmental burden and waste of resources; and the contents of impurity P and impurity B in the hydrogen obtained in Examples 1-5 are significantly lower than the contents of impurity P and impurity B in the hydrogen obtained in Comparative Examples 1-3, indicating that the adsorption effect of the physical and chemical dual adsorption adopted by the present invention is greater than the adsorption effect of using it alone, thereby being able to more thoroughly remove impurities and obtain higher purity hydrogen.

[0099] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0100] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for recovering hydrogen from electronic grade polysilicon reduction tail gas, characterized in that: The steps include: mixing a porous adsorbent material and a chemical absorbent to obtain a mixture; contacting the electronic-grade polysilicon reduction tail gas with the mixture to remove impurities in the electronic-grade polysilicon reduction tail gas to obtain a mixed gas, filtering and compressing the mixed gas to obtain high-purity hydrogen, and the high-purity hydrogen is used to prepare a raw material for electronic-grade polysilicon; Wherein, the electronic-grade polysilicon reduction tail gas is composed of hydrogen and impurities; The hydrogen content is ≥99.9%; The chemical absorbent includes an active ingredient and a solvent; The active ingredient includes at least one of triphenylmethane and diphenylcarbazone.

2. The recycling method according to claim 1, characterized in that: The chemical absorbent comprises triphenylmethane and diphenylcarbazone; the mass ratio of triphenylmethane to diphenylcarbazone is 1:(0.5-2); Optionally, the mass ratio of the chemical absorbent to the porous adsorbent material is 0.8-2; Optionally, the porous adsorption material includes at least one of activated carbon and molecular sieve; Optionally, the particle size of the porous adsorbent material is 325 mesh to 800 mesh.

3. The recycling method according to claim 1, characterized in that: The solvent includes benzene; Optionally, the concentration of the active ingredient in the solvent is 1.8 wt%-3.0 wt%.

4. The recycling method according to claim 1, characterized in that: The contacting temperature is 5°C-20°C.

5. The recycling method according to claim 1, characterized in that: The impurities include P and B impurities.

6. A device for recovering hydrogen from tail gas from reduction of electronic grade polysilicon, characterized in that: The recovery device comprises a first gas separation unit, a second gas separation unit, a buffer unit, and a compression unit connected in sequence; Wherein, the first gas separation unit comprises a gas separation reactor, and the gas separation reactor is filled with a mixture comprising a porous adsorption material and a chemical absorbent; The chemical absorbent comprises an active ingredient and a solvent; the active ingredient comprises at least one of triphenylmethane and diphenylcarbazone.

7. The recovery device according to claim 6, characterized in that: The gas separation reactor is provided with: a feed port for loading the chemical adsorbent into the gas separation reactor; A discharge port, used to discharge liquid components in the mixture; A gas inlet, used to provide electronic grade polysilicon reduction tail gas to the gas separation reactor; The gas outlet is connected to the second gas separation unit.

8. The recovery device according to claim 7, characterized in that: The feed port, the discharge port, the air inlet and the air outlet are all provided with control valves.

9. The recovery device according to claim 6, characterized in that: The first gas separation unit includes a plurality of the gas separation reactors, and each of the gas separation reactors is independently connected to the second gas separation unit.

10. The recovery device according to claim 6, characterized in that: The pore size of the filter material in the second gas separation unit is ≥50 mesh.

Images