Decarburization system for conveniently switching flow direction of carbon-containing mixture

Abstract

The utility model provides a carbon-containing mixture flow direction convenient switching decarburization system which comprises a decarburization tower, a first buffer tank, a second buffer tank, a main pipe inlet, a first main pipe outlet and a second main pipe outlet, the main pipe inlet is connected with a first connector, and the first main pipe outlet and the second main pipe outlet are respectively connected with a second connector and a first connector. The first buffer tank is provided with a first cut-out pipeline, a first backflow pipeline and a first control valve, the first cut-out pipeline is connected between the first buffer tank and the first connector, the first control valve is arranged on the first cut-out pipeline, and the first backflow pipeline is connected between the first buffer tank and the second connector. According to the device disclosed by the utility model, the mode of switching the feeding and discharging of a mixture is adopted, the adsorbed trichlorosilane, dichloro-silane and trichlorosilane are reversely washed and separated, and more gaps are released for the adsorption and reaction of the dichlorosilane, so that the reaction time of the dichlorosilane is shortened, and the production efficiency is improved. Therefore, the conversion rate of monochlorosilane and dichlorosilane is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of decarbonization in a distillation process of polysilicon production, and in particular to a decarbonization system for conveniently switching the flow direction of a carbon-containing mixture. Background Art

[0002] In the process of producing polysilicon by the modified Siemens method, distillation is an important key process for the refined production of high-purity trichlorosilane. The purity of trichlorosilane after distillation must reach above 99.9999999%, and the carbon content is one of the important factors affecting the purity.

[0003] Usually, in order to remove carbon-containing substances, adsorbents are filled into the decarbonization tower to adsorb various carbon sources, including monomethyldichlorosilane (abbreviated as monodichlorosilane), monomethyltrichlorosilane (abbreviated as monotrichlorosilane), trimethylmonochlorosilane (abbreviated as trichlorosilane), and dimethyldichlorosilane (abbreviated as dichlorosilane). The removal of monodichlorosilane is an important problem to be solved in this patent.

[0004] This patent adopts the principle of adsorption decarbonization. The adsorbent needs to be replaced frequently, resulting in high cost and complicated operation. Frequent replacement causes system instability and large fluctuations in the conversion rate of dichlorosilane. Utility Model Content

[0005] In view of the above defects, the utility model proposes a decarbonization system with convenient flow switching of carbon-containing mixture, comprising a decarbonization tower, a first buffer tank, a second buffer tank, a main pipe inlet, a first main pipe outlet, and a second main pipe outlet. The decarbonization tower is filled with adsorbent, and the decarbonization tower is provided with a first interface and a second interface, which are respectively used to input or discharge the mixture. The main pipe inlet is connected to the first interface, and the first main pipe outlet and the second main pipe outlet are respectively connected to the second interface and the first interface. The first buffer tank is provided with a first cut-out pipeline, a first reflux pipeline, and a first control valve. The first cut-out pipeline is connected between the first buffer tank and the first interface. The first control valve is provided on the first cut-out pipeline, and the first reflux pipeline is connected between the first buffer tank and the second interface. The second buffer tank is provided with a second cut-out pipeline, a second reflux pipeline, and a second control valve. The second cut-out pipeline is connected between the second buffer tank and the second interface. The second control valve is provided on the second cut-out pipeline, and the second reflux pipeline is connected between the second buffer tank and the first interface. A main branch pipe is also provided, and the main branch pipe is connected between the main pipe inlet and the second interface.

[0006] The removal principle of the utility model is to convert the dichloroethane and tetrasilane in the incoming material mixture into trichlorosilane. In order to ensure the conversion efficiency, the flow rate is detected in real time through the flow detector on the main pipe inlet, which is used to react the conversion rate of the adsorbent in the decarbonization kettle. When the flow rate decreases, the method of switching the mixture inlet and outlet is adopted to reversely flush and separate the adsorbed trichlorosilane, dichlorosilane and trichlorosilane, release more gaps for dichlorosilane to be adsorbed and react, thereby improving the conversion rate of dichlorosilane. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a comprehensive connection diagram of this solution.

[0008] Figure 2-5 The following is a connection diagram for four states.

[0009] In the figure: decarbonization tower 10, first interface 11, second interface 12, first buffer tank 20, first cut-out pipeline 21, first reflux pipeline 22, first control valve 23, second buffer tank 30, second cut-out pipeline 31, second reflux pipeline 32, second control valve 33, main pipe inlet 100, main branch pipe 101, flow detector 102, first main pipe outlet 200, second main pipe outlet 300. DETAILED DESCRIPTION

[0010] See also Figure 1-5 A decarbonization system for conveniently switching the flow direction of a carbon-containing mixture comprises: a decarbonization tower 10, a first buffer tank 20, a second buffer tank 30, a main pipe inlet 100, a first main pipe outlet 200, and a second main pipe outlet 300. The decarbonization tower 10 is filled with an adsorbent. The decarbonization tower 10 is provided with a first interface 11 and a second interface 12, which are respectively used to input or discharge the mixture. The main pipe inlet 100 is connected to the first interface 11, the first main pipe outlet 200 and the second main pipe outlet 300 are respectively connected to the second interface 12 and the first interface 11. The first buffer tank 20 is provided with a first cut-out pipeline 21, a first reflux pipeline 22, and a first control valve 23. The first cut-out pipeline 2 1 is connected between the first buffer tank 20 and the first interface 11, the first control valve 23 is arranged on the first cut-out pipeline 21, the first return pipeline 22 is connected between the first buffer tank 20 and the second interface 12, the second buffer tank 30 is provided with a second cut-out pipeline 31, a second return pipeline 32, and a second control valve 33, the second cut-out pipeline 31 is connected between the second buffer tank 30 and the second interface 12, the second control valve 33 is arranged on the second cut-out pipeline 31, the second return pipeline 32 is connected between the second buffer tank 30 and the first interface 11, and a main branch pipe 101 is also arranged, and the main branch pipe 101 is connected between the main pipe inlet 100 and the second interface 12.

[0011] In this solution, two buffer tanks are preset for the decarbonization tower 10, which are respectively connected to the first interface 11 and the second interface 12, and the two are used alternately. When the flow direction of the mixture is switched from bottom-in and top-out to top-in and bottom-out, the first buffer tank 20 and its components are started, and when the flow direction of the mixture is switched from top-in and bottom-out to bottom-in and top-out, the second buffer tank 30 and its components are started, thereby providing a buffer path for the incompletely reacted mixture during switching. After the operation is stable, the system is cut into the interior again without external discharge.

[0012] Furthermore, a flow detector 102 is also provided on the main pipe inlet 100 .

[0013] In specific implementation, during normal operation, the mixture flows in a bottom-in and top-out direction, such as Figure 2 , a mixture containing monodichlorosilane and tetrasilicon enters the decarbonization tower 10 from the main pipe inlet 100, and is discharged from the first main pipe outlet 200 after adsorption reaction;

[0014] When the flow data detected by the flow detector 103 drops, it indicates that the adsorbent is partially blocked or ineffective. At this time, the flow direction is switched, and the mixture enters the tower along the main branch pipe 101 and the second interface 12. The control valves on the first main pipe outlet 200 and the second main pipe outlet 300 are closed, and the first control valve 23 is opened to allow the mixture that has not been completely reacted in the tower to enter the first buffer tank 20. The control time is T1 (this time is the time for the mixture to flow out from the decarbonization tower during normal operation). After that, the control valve on the second main pipe outlet 300 is opened, the first control valve 23 is closed, and the mixture in the first buffer tank 20 is pumped into the tower again through the second interface. Figure 3 .

[0015] In another case, when operating normally, the mixture flows in the direction of top-in and bottom-out, such as Figure 4 , a mixture containing monodichlorosilane and tetrasilicon enters the decarbonization tower 10 from the main pipe inlet 100 and the main branch pipe 101 via the second interface, and is discharged from the second main pipe outlet 300 after adsorption reaction;

[0016] After running for a period of time, when the flow data detected by the flow detector 103 drops, it indicates that the adsorbent is partially blocked or ineffective. At this time, the flow direction is switched, and the mixture enters the tower along the first interface 11, and the control valves on the first main pipe outlet 200 and the second main pipe outlet 300 are closed, and the second control valve 33 is opened to allow the mixture that has not been completely reacted in the tower to enter the second buffer tank 30. The control time is T1. After that, the control valve on the first main pipe outlet 200 is opened, the second control valve 33 is closed, and the mixture in the second buffer tank 30 is pumped into the tower again through the first interface. Figure 5 .

[0017] The above completes the switching of the flow reverse in a cycle.

[0018] This solution is a preset mixture cut-out and buffer component for switching in two directions. When switching, it can be completed by simply switching the corresponding control valve. The operation is simple and the switching efficiency is high.

[0019] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of this patent.

Claims

1. A decarbonization system for conveniently switching the flow direction of a carbon-containing mixture, characterized in that include: It includes a decarbonization tower, a first buffer tank, a second buffer tank, a main pipe inlet, a first main pipe outlet, and a second main pipe outlet. The decarbonization tower is filled with adsorbent. The decarbonization tower is provided with a first interface and a second interface, which are respectively used to input or discharge the mixture. The main pipe inlet is connected to the first interface, and the first main pipe outlet and the second main pipe outlet are respectively connected to the second interface and the first interface. The first buffer tank is provided with a first cut-out pipeline, a first reflux pipeline, and a first control valve. The first cut-out pipeline is connected between the first buffer tank and the first interface. The first control valve is provided on the first cut-out pipeline. The first reflux pipeline is connected between the first buffer tank and the second interface. The second buffer tank is provided with a second cut-out pipeline, a second reflux pipeline, and a second control valve. The second cut-out pipeline is connected between the second buffer tank and the second interface. The second control valve is provided on the second cut-out pipeline. The second reflux pipeline is connected between the second buffer tank and the first interface. A main branch pipe is also provided, and the main branch pipe is connected between the main pipe inlet and the second interface.

2. The carbon-containing mixture flow direction convenient switching decarbonization system according to claim 1, characterized in that include: A flow detector is also provided on the main pipe inlet.

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