CN113666377A - Comprehensive energy utilization method for polycrystalline silicon tail gas - Google Patents
Comprehensive energy utilization method for polycrystalline silicon tail gas Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/08—Compounds containing halogen
- C01B33/107—Halogenated silanes
- C01B33/1071—Tetrachloride, trichlorosilane or silicochloroform, dichlorosilane, monochlorosilane or mixtures thereof
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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
- B01D53/14—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 by absorption
- B01D53/1412—Controlling the absorption process
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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
- B01D53/14—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 by absorption
- B01D53/1418—Recovery of products
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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
- B01D53/14—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 by absorption
- B01D53/1425—Regeneration of liquid absorbents
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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
- B01D53/14—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 by absorption
- B01D53/18—Absorbing units; Liquid distributors therefor
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
- C01B3/50—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/02—Silicon
- C01B33/021—Preparation
- C01B33/027—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material
- C01B33/03—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material by decomposition of silicon halides or halosilanes or reduction thereof with hydrogen as the only reducing agent
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B15/00—Sorption machines, plants or systems, operating continuously, e.g. absorption type
- F25B15/02—Sorption machines, plants or systems, operating continuously, e.g. absorption type without inert gas
- F25B15/06—Sorption machines, plants or systems, operating continuously, e.g. absorption type without inert gas the refrigerant being water vapour evaporated from a salt solution, e.g. lithium bromide
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
- F28D7/08—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being otherwise bent, e.g. in a serpentine or zig-zag
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/20—Halogens or halogen compounds
- B01D2257/204—Inorganic halogen compounds
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
Abstract
The invention discloses a comprehensive energy utilization method of polycrystalline silicon tail gas, which comprises at least one of the following modes: adding a water-cooled heat exchanger at the temperature of 7 ℃ in a reduction tail gas recovery steel structure system; and II, adding a water-cooling heat exchanger at the temperature of 7 ℃ in a cold hydrogenation tail gas condensation system. The invention aims to solve the problem of system energy consumption caused by the capacity improvement of reduction and matched processes thereof, and not only realizes the load problem of the capacity improvement of the system, but also solves the bottleneck of the capacity improvement of the reduction through the efficient utilization of energy by adding a water-cooled heat exchanger with the temperature of 7 ℃ in the existing recovery and/or cold hydrogenation system.
Description
Technical Field
The invention belongs to the technical field of polycrystalline silicon production, and particularly relates to a comprehensive energy utilization method of polycrystalline silicon tail gas.
Background
With the continuous improvement of the technical level of the photovoltaic industry, the scale of the polysilicon photovoltaic industry is gradually enlarged, and the reduction capacity of polysilicon is improved. The cold hydrogenation technology is used as a recycling process of byproducts in the production process of polycrystalline silicon, so that the production cost of the polycrystalline silicon can be effectively reduced, and the productivity of the polycrystalline silicon needs to be improved. In the production, the cold hydrogenation process needs to convert Silicon Tetrachloride (STC) which is a byproduct in the production of polycrystalline silicon into Trichlorosilane (TCS) under the conditions of high pressure and low temperature, and then the TCS is subjected to disproportionation reaction to produce silane. Along with the improvement of the cold hydrogenation production energy, in order to meet the production energy requirement, the processing capacity of a hydrogenation material and a refined material needs to be improved through the process flow optimization after the new rectification is matched. Therefore, in order to meet the requirement of improving the reduction capacity of the polycrystalline silicon, the capacity of the matched rectification, cold hydrogenation and recovery device needs to be improved.
However, from the viewpoint of system balance matching and operation conditions, the capacity of the polysilicon reduction device is further improved, but the improvement of the comprehensive yield of polysilicon products is limited, mainly because: at present, the maximum STC processing capacity of a single cold hydrogenation set is limited, and the cold hydrogenation yield cannot be further increased along with the increase of the reduction yield, which is generally shown by insufficient load of an ice machine, high inlet temperature of a silicon powder filter and large load of an electric heater. Meanwhile, the recovery system has limited summer throughput, such as insufficient air suction of a compressor and insufficient cold of an ice machine at 7 ℃ to-10 ℃, which causes capacity bottleneck of the whole system and cannot perfectly match the improvement of the reduction capacity at present. Therefore, the optimal matching of the system can be guaranteed only by systematically solving the problems, so that the system capacity of the polycrystalline silicon product is really further improved, and the capacity maximization and the cost optimization are realized.
The invention patent with publication number CN106395832A discloses a method for hydrogenating silicon tetrachloride, which connects a dechlorination hydrogenation reaction (a first reactor) of silicon tetrachloride and a trichlorosilane synthesis reaction (a second reactor) in series, and can inhibit the decomposition of trichlorosilane generated by a cold hydrogenation reaction by quenching tail gas of the first reactor, maintain the reaction progress of the cold hydrogenation reaction in the first reactor, and improve the conversion per pass of silicon tetrachloride. However, the method is not suitable for the existing device, because the cold hydrogenation device has large hydrogen circulation volume, high pressure, low synthesis reaction pressure and small reaction gas volume, additional equipment and pipelines are required to be matched with the cold hydrogenation device, the process cost is increased, and meanwhile, the problem that the equipment capacity of the device reaches the upper limit due to insufficient heat exchange cannot be effectively solved.
The invention patent with publication number CN107311184A discloses a production process for improving the conversion rate of trichlorosilane produced by cold hydrogenation, which fully utilizes the synthetic heat flow of chemical reaction by preheating hydrogen chloride gas to a proper range, improves the conversion rate, reduces the load of an electric heater and reduces the consumption of raw materials. However, when the process is used, due to the fact that the granularity of the fine silicon powder escaping is reduced due to the fact that a large amount of HCL is increased, the heat exchanger is scaled, the heat exchange efficiency is reduced, the equipment load is increased, and accordingly the productivity is affected.
Disclosure of Invention
The invention aims to solve the problem of system energy consumption caused by the capacity improvement of reduction and matched processes thereof, and provides a comprehensive energy utilization method of polycrystalline silicon tail gas, which not only realizes the load problem of the capacity improvement of a system, but also solves the bottleneck of the capacity improvement of reduction through the efficient utilization of energy by adding a water-cooled heat exchanger with the temperature of 7 ℃ in the existing recovery and/or cold hydrogenation system.
The invention is realized by the following technical scheme: a comprehensive energy utilization method for polycrystalline silicon tail gas comprises at least one of the following modes:
adding a water-cooled heat exchanger at the temperature of 7 ℃ in a reduction tail gas recovery steel structure system;
and II, adding a water-cooling heat exchanger at the temperature of 7 ℃ in a cold hydrogenation tail gas condensation system.
In the mode I, a newly-added 7 ℃ water-cooling heat exchanger is connected in parallel with a 7 ℃ water cooler of lithium bromide of the reduction tail gas recovery steel structure system.
In the mode I, a water-cooling heat exchanger with the temperature of 7 ℃ is additionally arranged between a steel structure 1-level condenser and a steel structure 2-level condenser of the steel structure system for recovering the reduction tail gas.
In the mode I, the temperature of hydrogen entering the adsorption tower in the reduction tail gas recovery steel structure system is controlled to be-36 to-40 ℃.
According to the content of silane and hydrogen chloride in the product hydrogen of the adsorption tower, the spraying circulation amount of the tail gas of the adsorption tower is increased.
In the mode II, a water-cooling heat exchanger with the temperature of 7 ℃ is additionally arranged in front of a two-stage condenser of the cold hydrogenation tail gas condensation system.
The water-cooling heat exchanger is a coiled pipe heat exchanger.
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) the invention provides a water-cooling heat exchanger with 7 ℃ added in a reduction tail gas recovery steel structure system, aiming at the problem that the summer treatment capacity of the recovery system is limited after the existing reduction capacity is improved, the water-cooling heat exchanger comprises a 7 ℃ water cooler connected with a lithium bromide in parallel, and a 7 ℃ water-cooling heat exchanger additionally arranged between a steel structure 1-level condenser and a steel structure 2-level condenser, through energy consumption accounting, the problems of insufficient air suction of a compressor and insufficient cold of an ice machine with 7 ℃ and-10 ℃ in the existing recovery steel structure system can be solved, meanwhile, the added heat exchanger adopts 7 ℃ water as a refrigerant, the energy consumption of the system can be effectively controlled, the treatment capacity of the recovery system is improved, energy can be effectively saved, and the energy consumption is reduced.
(2) According to the invention, the treatment capacity of the reduction tail gas recovery steel structure system is improved, the temperature of hydrogen entering the adsorption tower in the system can be effectively reduced, the treatment capacity of the adsorption tower can be further improved by reducing the temperature of the hydrogen, and meanwhile, the spraying circulation capacity of the tail gas of the adsorption tower is improved according to the content of silane and hydrogen chloride in the hydrogen of the adsorption tower product, so that the effective treatment of the reduction tail gas after the reduction capacity is improved is realized.
(3) Aiming at the problem that the improvement of the cold hydrogenation yield is limited after the improvement of the existing reduction capacity, the invention provides the method that the water-cooling heat exchanger with the temperature of 7 ℃ is additionally arranged in front of the two-stage condenser of the cold hydrogenation tail gas condensation system, so that the problem that the cold quantity of the condenser with the temperature of-40 ℃ in the existing condensation system is insufficient can be solved, meanwhile, the added heat exchanger adopts water with the temperature of 7 ℃ as a refrigerant, the energy consumption of the system can be effectively controlled, the treatment capacity of the condenser with the temperature of-40 ℃ is improved, and meanwhile, the energy can be effectively saved, and the energy consumption is reduced.
(4) The water-cooled heat exchangers at 7 ℃ adopt the coiled heat exchangers, so that the heat exchange efficiency is high, the energy is saved, in addition, the problem of silicon powder scaling in the tubes after the reduction tail gas flow speed is improved can be reduced, and the energy consumption of the system can be effectively reduced.
In summary, the invention provides a comprehensive energy utilization method for solving the problem that the yield of a series of matching equipment cannot be improved due to the improvement of reduction capacity, and the comprehensive energy utilization method solves the capacity bottleneck of a main polycrystalline silicon device on the premise of greatly reducing power consumption and ensuring system safety by selectively adding a water-cooled heat exchanger with the temperature of 7 ℃ in the existing polycrystalline silicon system, so that the balance of a polycrystalline silicon production system is optimized, and the competitive advantages of cost and unit consumption after the capacity is improved are kept.
Drawings
FIG. 1 is a schematic process flow diagram of a steel structure recovery system by reducing tail gas.
FIG. 2 is a schematic process flow diagram of a steel structure 1-7 grade cooler in the steel structure system for recovering reduction tail gas.
FIG. 3 is a process flow diagram of the cold hydrogenated tail gas condensing system of the present invention.
Fig. 4 is a schematic structural diagram of the tube-wound heat exchanger according to the present invention.
Detailed Description
The objects, technical solutions and advantageous effects of the present invention will be described in further detail below.
It is to be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention claimed, and unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
In the polysilicon production system, with the improvement of the reduction capacity, the processing capacity of the cold hydrogenation and recovery system is continuously increased, which brings the increase of the equipment load and the more energy consumption, and the technical bottlenecks can always contribute to the development of polysilicon enterprises. In order to solve the problems, newly-added corollary equipment can be adopted, such as a set of cold hydrogenation or recovery system is newly added, but the newly-added device has high investment cost, long period and high reconstruction difficulty and is not friendly to polysilicon enterprises; it is also possible to solve the problems of upper limit of treatment and treatment efficiency of some equipments by two-stage reaction and preheating as in the prior art (CN 106395832A and CN 107311184A), but these are only suitable for specific equipments, and no solution is provided for other system problems caused by the increase of reduction capacity. The invention aims to fully utilize the existing device, find a device which can quickly solve the key problem disturbing the existing polysilicon reduction capacity improvement, realize the integral improvement of the system yield by comprehensively utilizing the system energy, and has the characteristics of short period, small investment and quick effect.
The following is an exemplary embodiment to illustrate the specific embodiments of the present invention, and the scope of the present invention is not limited to the following embodiment.
Example 1:
the embodiment is a method for comprehensively utilizing energy of polycrystalline silicon tail gas, and the method mainly aims at the problems that after the existing reduction capacity is improved, the amount of the reduction tail gas is increased, and the subsequent treatment capacity of a recovery system and a cold hydrogenation system of the reduction tail gas cannot be further improved due to the improvement of energy consumption. The solution comprises the following steps: a water-cooled heat exchanger with the temperature of 7 ℃ is added in a reduction tail gas recovery steel structure system, and a water-cooled heat exchanger with the temperature of 7 ℃ is added in a cold hydrogenation tail gas condensation system.
Firstly, the steel structure system for recovering the reduction tail gas is to reduce chlorosilane (trichlorosilane, silicon tetrachloride and dichlorosilane) and H in the tail gas2And HCl, chlorosilane is sent to a recovery and rectification device, and H2Sending the mixture to an adsorption device for purification, then sending the mixture to a reduction device, and sending HCl to trichlorosilane for hydrationThe device is used as raw material gas, and the process flow is shown in figure 1 and figure 2.
With the continuous increase of the treatment capacity of the reduction tail gas, in the existing steel structure recovery system, because the air suction capacity of a compressor and the cold capacity of an ice machine at 7 ℃ and 10 ℃ below zero are insufficient, the treatment capacity of the steel recycling system is limited in summer, and in order to accurately solve the problems of insufficient cooling capacity and limited treatment of the system in summer, the embodiment starts from energy utilization efficiency, the comprehensive simulation calculation and design are carried out on the utilization of heat energy, a newly-added 7 ℃ water-cooling heat exchanger is connected in parallel with a 7 ℃ lithium bromide water cooler of the existing reduction tail gas recovery steel structure system, the 7 ℃ water-cooling heat exchanger is utilized to solve the problems of insufficient air suction quantity of a compressor and insufficient cold quantity of the 7 ℃ lithium bromide water cooler, and simultaneously, a7 ℃ water-cooling heat exchanger is additionally arranged between a steel structure 1-grade condenser and a steel structure 2-grade condenser of the existing reduction tail gas recovery steel structure system, so that the problem of insufficient cold energy of a-10 ℃ ice machine of a steel structure 3-grade cooler is solved. On the other hand, the temperature of hydrogen entering the adsorption tower in the reduction tail gas recovery steel structure system can be reduced from minus 36 ℃ to minus 40 ℃, and H can be ensured under the condition that the air inlet load of the adsorption tower is increased2Thereby achieving the purpose of improving the treatment capacity of the adsorption tower.
The following is the simulated condition distribution of the mass flow of each component of the hydrogen of the absorption tower product:
simulation state 1: the daily yield of the polycrystalline silicon is 63.5 t/day, and the spraying circulation amount (circulating spraying chlorosilane liquid of the absorption tower) is 100m for carrying out the year/h.
TABLE 1 absorption column-40 ℃ inlet air
TABLE 2 absorption tower-36 deg.C intake (summer)
As can be seen from tables 1 and 2, the temperature of H is varied2Quality of hydrogen (chlorosilane) product after entering absorption towerHCl content) of the feed gas H2The temperature is higher, the absorption capacity of the absorption tower is weakened, and the hydrogen quantity is difficult to increase.
Simulation state 2: the daily yield of the polysilicon is 67.5 t/day.
TABLE 3 high-temperature shift of the absorber at-40 ℃ and spray circulation rate of 100 m/h
TABLE 4 high-temperature absorption tower inlet gas at-40 deg.C and spraying circulation rate 120 m/h
As can be seen from tables 3 and 4, H at different temperatures2The quality (chlorosilane and HCl content) of the product hydrogen after entering the absorption tower is compared, and after the heat exchanger is added, H is fed2The temperature is reduced, the absorption capacity of the absorption tower is improved, and the absorption effect after the hydrogen amount is improved is achieved.
Furthermore, in the actual operation process, along with the increase of the treatment capacity of the adsorption tower, the content of silane and chlorosilane in the product hydrogen obtained by the adsorption tower can be basically maintained unchanged by reducing the hydrogen inlet temperature of the adsorption tower, if the spraying circulation amount is properly increased, the content of hydrogen chloride in the hydrogen is greatly reduced, and the content of silane is slightly reduced.
Along with the continuous increase of the treatment capacity of the reduction tail gas, in the production process of the cold hydrogenation device, the heat exchange capacity is reduced due to the fact that silicon powder scaling exists in the energy-saving heat exchanger with the process characteristics, and the mixed gas (H) correspondingly enters the electric heater2And silicon tetrachloride) is low, the temperature of reaction gas entering the silicon powder filter is increased, the temperature of an inlet of a heat exchanger of a cooling system is increased after cold hydrogenation (meanwhile, scaling and heat exchange of a circulating water heat exchanger are attenuated), so that the load of a cryogenic heat exchanger is increased (the load demand of an ice machine is large), and the cold hydrogenation yield cannot be further improved due to the factors. To accurately solve the problem of the increased load of an ice machine caused by the process characteristics in a cold hydrogenation systemIn this embodiment, from the same viewpoint of energy utilization efficiency, comprehensive simulation calculation and design are performed on heat energy utilization, and a water-cooled heat exchanger at 7 ℃ is added to the existing cold hydrogenation tail gas condensation system, as shown in fig. 3. The cold hydrogenation tail gas condensing system currently adopts two stages of condensers, namely a first-stage cooler (E0212), a circulating water cooler and a second-stage cooler (E0213), and the condensing temperature is-40 ℃. The problem of insufficient cold energy of the condenser at minus 40 ℃ in the two-stage condenser can be effectively solved by additionally arranging the water-cooling heat exchanger at 7 ℃ in front of the two-stage condenser.
In order to further solve the problem of silicon powder scaling in the tube after the flow velocity of the reduction tail gas is increased, the water-cooled heat exchangers at 7 ℃ in the embodiment all adopt a wound tube high-efficiency heat exchanger, as shown in fig. 4.
According to the embodiment, the comprehensive simulation calculation and design are carried out on the utilization of heat energy, the water-cooled heat exchanger with the temperature of 7 ℃ is respectively added in the steel recovery structure system and the cold hydrogenation tail gas condensation system, the capacity bottleneck of the polysilicon main body device is solved on the premise of greatly reducing the power consumption and ensuring the system safety, the balance of the polysilicon production system is optimized, and the cost and unit consumption competitive advantage after the capacity is improved are kept.
(one) the economic benefits achieved are as in table 5 below.
TABLE 5 economic benefits
(II) energy saving benefit
The cold hydrogenation (3 +1 set) can save the electricity consumption by 760 and 912 ten thousand yuan/year in total, the recovery steel structure and the cold hydrogenation ice machine set can save the electricity consumption by 150 and 170 ten thousand yuan/year in total, the total benefit can reach 1000 ten thousand yuan/year, and the electricity-saving benefit is obvious.
(III) the yield-increasing benefits are as follows in Table 6.
TABLE 6 benefit of increasing yield
Under the condition of increasing the yield of the whole device, the feed rate of a single set of STC can be increased to 68-70t/h, the total feed rate of cold hydrogenation can be increased to 10-15t/h to 224-.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.
Claims (7)
1. A comprehensive energy utilization method of polycrystalline silicon tail gas is characterized by comprising the following steps: at least one of the following modes is included:
adding a water-cooled heat exchanger at the temperature of 7 ℃ in a reduction tail gas recovery steel structure system;
and II, adding a water-cooling heat exchanger at the temperature of 7 ℃ in a cold hydrogenation tail gas condensation system.
2. The method for comprehensively utilizing the energy of the polycrystalline silicon tail gas as claimed in claim 1, wherein the method comprises the following steps: in the mode I, a newly-added 7 ℃ water-cooling heat exchanger is connected in parallel with a 7 ℃ water cooler of lithium bromide of the reduction tail gas recovery steel structure system.
3. The method for comprehensively utilizing the energy of the polycrystalline silicon tail gas as claimed in claim 1, wherein the method comprises the following steps: in the mode I, a water-cooling heat exchanger with the temperature of 7 ℃ is additionally arranged between a steel structure 1-level condenser and a steel structure 2-level condenser of the steel structure system for recovering the reduction tail gas.
4. The method for comprehensively utilizing the energy of the polycrystalline silicon tail gas as claimed in claim 1, wherein the method comprises the following steps: in the mode I, the temperature of hydrogen entering the adsorption tower in the reduction tail gas recovery steel structure system is controlled to be-36 to-40 ℃.
5. The method for comprehensively utilizing the energy of the polycrystalline silicon tail gas as claimed in claim 4, wherein the method comprises the following steps: according to the content of silane and hydrogen chloride in the product hydrogen of the adsorption tower, the spraying circulation amount of the tail gas of the adsorption tower is increased.
6. The method for comprehensively utilizing the energy of the polycrystalline silicon tail gas as claimed in claim 1, wherein the method comprises the following steps: in the mode II, a water-cooling heat exchanger with the temperature of 7 ℃ is additionally arranged in front of a two-stage condenser of the cold hydrogenation tail gas condensation system.
7. The method for comprehensively utilizing the energy of the polycrystalline silicon tail gas as claimed in claim 1, wherein the method comprises the following steps: the water-cooling heat exchanger is a coiled pipe heat exchanger.
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| CN102838121A (en) * | 2012-09-18 | 2012-12-26 | 特变电工新疆硅业有限公司 | Method and device for recycling tail gas in production of polycrystalline silicon |
| CN104383704A (en) * | 2014-09-19 | 2015-03-04 | 燕山大学 | Step heating method and heating system for preheating of gas fractionating tower inlet material |
| CN204522364U (en) * | 2015-03-05 | 2015-08-05 | 国电内蒙古晶阳能源有限公司 | Polysilicon tail gas recovery system |
| CN204509175U (en) * | 2015-03-18 | 2015-07-29 | 山西恒大化工有限责任公司 | Relate to the carbon black production device that tail gas recycle utilizes |
| CN209042392U (en) * | 2018-09-11 | 2019-06-28 | 广东天源环境科技有限公司 | A kind of pyrolysis system utilized with tail gas recycle |
| CN113277471A (en) * | 2021-06-10 | 2021-08-20 | 中国恩菲工程技术有限公司 | Method and device for recovering reduction tail gas in polycrystalline silicon production |
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