ZHOU, Yong (No. 3001, Hengping RoadPingshan, Longgan, Shenzhen Guangdong 8, 518118, CN)
DING, Xianbo (No. 3001, Hengping RoadPingshan, Longgan, Shenzhen Guangdong 8, 518118, CN)
ZHOU, Yong (No. 3001, Hengping RoadPingshan, Longgan, Shenzhen Guangdong 8, 518118, CN)
| What is claimed is: 1 . A fluidized bed reactor, comprising: a reactor body having a solid inlet, a gas inlet and an outlet; and a plurality of fluidized plates disposed inside the reactor body at intervals in an up and down direction and each fluidized plate having a plurality of apertures, in which an area of each aperture in an upper fluidized plate of two adjacent fluidized plates is larger than that in a lower fluidized plate of the two adjacent fluidized plates. 2. The fluidized bed reactor according to claim 1 , wherein about 3 to 20 fluidized plates are disposed. 3. The fluidized bed reactor according to claim 2, wherein about 5 to 10 fluidized plates are disposed. 4. The fluidized bed reactor according to claim 1 , wherein distances between every two adjacent fluidized plates are about 0.2 m to about 2 m. 5. The fluidized bed reactor according to claim 1 , wherein distances between every two adjacent fluidized plates are the same. 6. The fluidized bed reactor according to claim 1 , wherein the outlet is formed at a top of the reactor body, one solid inlet is formed at an upper portion of the reactor body, and the gas inlet is formed at a bottom of the reactor body. 7. The fluidized bed reactor according to claim 6, wherein at least one solid inlet is further formed between at least two adjacent fluidized plates. 8. The fluidized bed reactor according to claim 1 , wherein the apertures in the uppermost fluidized plate have a diameter of about 10 mm to about 20 mm, and the apertures in the lowermost fluidized plate have a diameter of about 0.1 mm to about 0.2 mm. 9. The fluidized bed reactor according to claim 1 , wherein the apertures in each fluidized plate have a funnel shape. 10. A device for preparing trichlorosilane by hydrogenating silicon tetrachloride, comprising: a fluidized bed reactor including, a reactor body having a solid inlet, a gas inlet and an outlet, and a plurality of fluidized plates disposed inside the reactor body at intervals in an up and down direction and each fluidized plate having a plurality of apertures, in which an area of each aperture in an upper fluidized plate of two adjacent fluidized plates is larger than that in a lower fluidized plate of the two adjacent fluidized plates; a silicon storage tank configured to connect to the solid inlet and store silicon materials; a hydrogen storage tank configured to connect to the gas inlet and store hydrogen gas; a silicon tetrachloride storage tank configured to connect to the gas inlet and store silicon tetrachloride; a separator configured to connect to the outlet of the reactor body and separate products from the fluidized bed reactor; a buffering storage tank configured to connect to the separator and store trichlorosilane and silicon tetrachloride separated from the products; a distillation tower configured to connect to the buffering storage tank and separate trichlorosilane from silicon tetrachloride; and a trichlorosilane storage tank configured to connect to the distillation tower and store the separated trichlorosilane. 11 . The device according to claim 10, wherein about 3 to 20 fluidized plates are disposed. 12. The device according to claim 11 , wherein about 5 to 10 fluidized plates are disposed. 13. The device according to claim 10, wherein distances between every two adjacent fluidized plates are about 0.2 m to about 2 m. 14. The device according to claim 10, wherein distances between every two adjacent fluidized plates are the same. 15. The device according to claim 10, wherein the outlet is formed at a top of the reactor body, one solid inlet is formed at an upper portion of the reactor body, and the gas inlet is formed at a bottom of the reactor body. 16. The device according to claim 10, wherein at least one solid inlet is formed between at least two adjacent fluidized plates. 17. The device according to claim 10, wherein the apertures in the uppermost fluidized plate have a diameter of about 10 mm to about 20 mm, and the apertures in the lowermost fluidized plate have a diameter of about 0.1 mm to about 0.2 mm. 18. The device according to claim 10, wherein the apertures in each fluidized plate have a funnel shape. 19. The device according to claim 10, wherein the hydrogen storage tank is connected to an outlet of the separator so as to recycle the hydrogen separated from the products in the separator; and the distillation tower is connected to the silicon tetrachloride storage tank so as to store the silicon tetrachloride separated in the distillation tower. |
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority and benefits of Chinese Patent Application No.
201020213306.2 filed with the State Intellectual Property Office of P. R. China on May 31 st 2010, the entire content of which is incorporated herein by reference.
TECHNICAL FIELD
The present disclosure relates to a device for preparing trichlorosilane by hydrogenating silicon tetrachloride, more particularly relates to a fluidized bed reactor used in the device.
BACKGROUND
In recent years, with the fast development of electronics and photovoltaic industries, the polycrystalline silicon industry has been greatly developed. Currently, the main conventional method for producing polycrystalline silicon is Siemens Process. However, a great amount of by-product SiCI 4 (silicon tetrachloride) will be produced, which may bring challenge to the waste treatment as well as the environment and may affect the development of the whole industry if the by-product SiCI 4 is not properly treated.
Therefore, if a reasonable and feasible solution can be developed to realize the recycling of the main side product SiCI 4 and further converting SiCI 4 into S1 HCI3, not only the production cost of polycrystalline silicon may be effectively reduced, but also the environment may be better protected and the healthy development of the industry may be realized.
There are mainly two conventional processes to prepare S1 HCI3 by hydrogenating SiCI 4 :
A), a high temperature hydrogenation process of SiCI 4 and hydrogen at around 1250 ° C without any catalyst to produce S1HCI3, and
B). a low temperature hydrogenation process of SiCI 4 , hydrogen and silicon at around
500 ° C under about 2.5 MPa in the presence of a catalyst to produce S1HCI3.
Compared to the high temperature hydrogenation process, the low temperature hydrogenation process may have lower energy consumption and higher conversion efficiency. However, the low temperature hydrogenation process requires high pressure conditions so that there will be strict requirements for the production device.
A conventional device applied in low temperature hydrogenation process mainly comprises a hydrogen and silicon tetrachloride storage tank, a silicon powder and catalyst storage tank, a fluidized bed reactor, a separator, a buffering storage tank, a distillation tower and so on; in which the fluidized bed reactor has a gas inlet at a bottom and a solid particle inlet at an upper portion and an outlet at a top thereof. To apply the conventional fluidized bed reactor, the silicon powder and the catalyst are mixed uniformly or formed into alloy particles before added into the fluidized bed reactor, and consequently the particle size of the raw materials is required to be within the range of about 100 m to 300 m so as to ensure good fluidizing state and complete reaction, because incomplete reaction may cause the particles to block the pipes. Moreover, after the reaction, the catalyst may go out from the outlet of the device and may be separated in the separator. To continue the reaction, the silicon powder and the catalyst are continuously mixed or formed into alloy particles and then added into the reactor, and the catalyst are continuously collected and reused after the reaction. Furthermore, the catalyst may easily block the pipes and cause incomplete reaction, thus bringing many uncertainties to continuous production. In a word, the feeding process is complicated and the pipes may be blocked easily, which is not beneficial to realize continuous production.
SUMMARY
An embodiment of the present disclosure provides a fluidized bed reactor, comprising: a reactor body having a solid inlet, a gas inlet and an outlet; and a plurality of fluidized plates disposed inside the reactor body at intervals in an up and down direction and each fluidized plate having a plurality of apertures, in which an area of each aperture in an upper fluidized plate of two adjacent fluidized plates is larger than that in a lower fluidized plate of the two adjacent fluidized plates.
An embodiment of the present disclosure provides a device for preparing trichlorosilane by hydrogenating silicon tetrachloride, comprising: a fluidized bed reactor; a silicon storage tank configured to connect to the solid inlet and store silicon materials; a hydrogen storage tank configured to connect to the gas inlet and store hydrogen gas; a silicon tetrachloride storage tank configured to connect to the gas inlet and store silicon tetrachloride; a separator configured to connect to the outlet of the reactor body and separate products from the fluidized bed reactor; a buffering storage tank configured to connect to the separator and store trichlorosilane and silicon tetrachloride separated from the products; a distillation tower configured to connect to the buffering storage tank and separate trichlorosilane from silicon tetrachloride; and a trichlorosilane storage tank configured to connect to the distillation tower and store the separated trichlorosilane. The fluidized bed reactor comprises a reactor body having a solid inlet, a gas inlet and an outlet; and a plurality of fluidized plates disposed inside the reactor body at intervals in an up and down direction and each fluidized plate having a plurality of apertures, in which an area of each aperture in an upper fluidized plate of two adjacent fluidized plates is larger than that in a lower fluidized plate of the two adjacent fluidized plates.
The device for preparing trichlorosilane by hydrogenating silicon tetrachloride may solve the problem of difficult feeding of conventional reactors. There may be no requirements for the particle size of the silicon powders. Silicon powders may have a particle size of as large as decimeter or millimeter scale or as small as micrometer scale. Meanwhile, in order to prepare S1 HCI3, the activation and the reaction of the raw materials silicon powders may be carried out simultaneously in the reactor, without a step of activating silicon powders before entering into the reactor. Moreover, multi-stage fluidization may be realized. The reaction yield may be improved, and the problems of the feeding control and the pipeline blocking may be solved, thus realizing long-time stable production.
Additional aspects and advantages of the embodiments of the present disclosure will be given in part in the following descriptions, become apparent in part from the following descriptions, or be learned from the practice of the embodiments of the present disclosure. DESCRIPTION OF THE DRAWINGS
The foregoing and other features and advantages of the disclosure will become apparent and more readily appreciated from the following descriptions taken in conjunction with the accompanying drawings in which:
Fig. 1 is a block diagram of the device for preparing trichlorosilane by hydrogenating silicon tetrachloride according to some embodiments of the present disclosure;
Fig. 2 is a schematic view of the fluidized bed reactor according to some embodiments of the present disclosure;
Fig. 3 is a schematic view of the upper fluidized plate in the fluidized bed reactor according to some embodiments of the present disclosure; and
Fig. 4 is a schematic view of the lower fluidized plate in the fluidized bed reactor according to some embodiments of the present disclosure.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Reference will be made in detail to embodiments of the present disclosure. The embodiments described herein with reference to the accompanying drawings are explanatory, illustrative, and used to generally understand the present disclosure. The embodiments shall not be construed to limit the present disclosure. The same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions.
According to some embodiments of the present disclosure, as shown in Fig. 1 and Fig. 2, the fluidized bed reactor 1 comprises a reactor body 10 having a solid inlet 13, a gas inlet 12 and an outlet 14; and a plurality of fluidized plates 11 disposed inside the reactor body 10 at intervals in an up and down direction and each fluidized plate 11 having a plurality of apertures, in which an area of each aperture in an upper fluidized plate 11 (as shown in Fig. 3) of two adjacent fluidized plates 11 is larger than that in a lower fluidized plate 11 (as shown in Fig. 4) of the two adjacent fluidized plates 11 .
In some embodiments, about 3 to 20 fluidized plates are disposed. In some preferred embodiments, about 5 to 10 fluidized plates are disposed.
In some embodiments, the distance between two adjacent fluidized plates 11 may be about 0.2 m to about 2 m and may not necessarily be the same. In some embodiments, the distance between every two fluidized plates 11 may be decreased or increased from top to bottom. In some preferred embodiments, the distances between every two adjacent fluidized plates 11 are the same.
By adopting the above mentioned fluidized bed reactor 1 , the catalyst and silicon powder may not need to be first mixed and then added into the solid inlet 13. The catalyst particles with a size slightly larger than the size of the apertures in the upper fluidized plate 11 may be added between two adjacent fluidized plates such that the catalyst may be restricted between the two adjacent fluidized plates 11 during the reaction and may not go out from the outlet 14 and block the pipes.
In some embodiments, the outlet 14 is formed at an upper portion of the reactor body 10. In a preferred embodiment, the outlet 14 is formed at a top of the reactor body 10. In some embodiments, one solid inlet 13 is formed at an upper portion of the reactor body 10, and the gas inlet 12 is formed at a bottom of the reactor body 10.
In some embodiments, only one solid inlet 13 may be disposed. After prepared by simply crushing of the industrial silicon powder, the silicon particles may be directly added into the fluidized bed reactor 1 through the solid inlet 13. As each fluidized plate 11 has a plurality of apertures and the area of the apertures are decreased from top fluidized plate 11 to bottom fluidized plate 11 , the fluidized plates 11 may serve as a filter. Therefore the silicon particles having a size larger than that of the apertures in a fluidized plate are kept on the fluidized plate, and the silicon particles having a size smaller than that of the apertures in the fluidized plate may drop to the next fluidized plate. Therefore, the particles with different sizes may be distributed on different fluidized plates 11 in turn and consequently the reaction may be carried out completely.
In some embodiments, as shown in Fig. 1 and Fig. 2, at least one solid inlet 13 is further formed between at least two adjacent fluidized plates 11 . It's not necessary that a solid inlet 13 is formed between every two fluidized plates 11 , the solid inlets 13 may be selectively formed between some of the two adjacent fluidized plates 11 , and select suitable solid inlets 13 according to the size of the silicon particles so that various silicon particles with different diameters may be added.
In some embodiments, the apertures in the fluidized plate 11 may have a diameter of about 0.1 mm to about 20 mm. In a preferred embodiment, the apertures in the uppermost fluidized plate have a diameter of about 10 mm to about 20 mm, and the apertures in the lowermost fluidized plate have a diameter of about 0.1 mm to about 0.2 mm.
In some embodiments, the apertures in each fluidized plate 11 may have a funnel shape.
According to an embodiment of the present disclosure, a device for preparing trichlorosilane by hydrogenating silicon tetrachloride is also provided, which comprises: a fluidized bed reactor 1 ; a silicon storage tank 8 configured to connect to the solid inlet 13 and store silicon materials; a hydrogen storage tank 7 connected to the gas inlet 12 and store hydrogen gas; a silicon tetrachloride storage tank 6 connected to the gas inlet 12 and store silicon tetrachloride; a separator 2 configured to connect to the outlet 14 of the reactor body 10 and separate products from the fluidized bed reactor 1 ; a buffering storage tank 3 configured to connect to the separator 2 and store trichlorosilane and silicon tetrachloride separated from the products; a distillation tower 4 configured to connect to the buffering storage tank 3 and separate trichlorosilane from silicon tetrachloride; and a trichlorosilane storage tank 5 configured to connect to the distillation tower 4 and store the separated trichlorosilane. The fluidized bed reactor 1 comprises a reactor body 10 having a solid inlet 13, a gas inlet 12 and an outlet 14; and a plurality of fluidized plates 11 disposed inside the reactor body 10 at intervals in an up and down direction and each fluidized plate 11 having a plurality of apertures, in which an area of each aperture in an upper fluidized plate of two adjacent fluidized plates 11 is larger than that in a lower fluidized plate of the two adjacent fluidized plates 11 .
In a preferred embodiment, the separated hydrogen and silicon tetrachloride may be recycled. Particularly, the hydrogen storage tank 7 is connected to an outlet of the separator 2 through a pipe so as to recycle the hydrogen separated from the products in the separator 2; and the distillation tower 4 is connected to the silicon tetrachloride storage tank 6 through a pipe so as to store the silicon tetrachloride separated in the distillation tower 4. The detailed process of the above embodiment is shown in Fig. 1 . Hydrogen supplied by the hydrogen storage tank 7 and silicon tetrachloride liquid supplied by the silicon tetrachloride storage tank 6 via a feed pump 61 pass through pipes into a heater 15 and is heated in the heater 15 to form a mixed gas, which enters into the bottom of the fluidized bed reactor 1 . An appropriate amount of catalyst is filled between every two fluidized plates in the fluidized bed reactor 1 , and industrial silicon powder is supplied by the silicon storage tank 8 via the solid inlet 13. After the reaction, trichlorosilane gas product, unreacted silicon dust, silicon tetrachloride gas and hydrogen are all discharged from the outlet 14 and enter into the separator 2. After separated in the separator 2, the dust and the particles are discharged from a bottom 20 of the separator 2, and the separated hydrogen is pressurized by a booster fan 21 and sent to the hydrogen storage tank 7 so as to recycle the hydrogen separated from the products in the separator 2. The mixed gas of trichlorosilane and silicon tetrachloride is cooled to form a liquid mixture of trichlorosilane and silicon tetrachloride, which enters into the buffering storage tank 3. The liquid mixture of trichlorosilane and silicon tetrachloride in the buffering storage tank 3 passes through a feeding pump 34 into the distillation tower 4 to separate trichlorosilane from silicon tetrachloride. Trichlorosilane is cooled and collected into the trichlorosilane storage tank 5, and silicon tetrachloride enters into the silicon tetrachloride storage tank 6 via an outlet of the distillation tower 4 for further hydrogenating reaction.
Although explanatory embodiments have been shown and described, it would be appreciated by those skilled in the art that changes, alternatives, and modifications can be made in the embodiments without departing from the spirit and the principles of the disclosure. Such changes, alternatives, and modifications all fall into the scope of the claims and their equivalents.
Next Patent: METHOD AND DEVICE FOR ON-LINE ADAPTATION OF MEDIA CONTENT