Device for improving conversion rate of cold hydrogenated silicon powder

Abstract

The utility model provides a device for improving the conversion rate of cold hydrogenated silicon powder. The device comprises an external dust remover (2) in fluid connection with a top discharge hole (13) of a fluidized bed (1) in a cold hydrogenation production process; a bottom outlet of the external dust remover (2) is in fluid connection with a top inlet of the reactor (3); a top outlet of the reactor (3) is in fluid connection with a top inlet of the chlorosilane storage tank (5) after sequentially passing through a first heat exchange channel of the heat exchanger (4) and a condensation channel of the condenser (6); a top outlet of the chlorosilane storage tank (5) is connected with a second heat exchange channel outlet of the heat exchanger (4) in parallel and then is in fluid connection with a bottom inlet of the reactor (3).

Description

TECHNICAL FIELD

[0001] The utility model relates to a silicon powder conversion device, in particular to a device of improving the conversion rate of cold hydrogenated silicon powder. BACKGROUND

[0002] This part provides only background information related to the present disclosure, which does not necessarily constitute prior art known to those skilled in the art.

[0003] In the production of polysilicon, the production raw material trichlorosilane is prepared by cold hydrogenation production process. In the existing cold hydrogenation production process, silicon powder, hydrogen and silicon tetrachloride generate trichlorosilane under the action of catalyst in the fluidized bed, trichlorosilane enters the venturi scrubber through the gas phase pipeline, removes the silicon powder, and then enters the stripping tower for cooling. After cooling, the trichlorosilane is sent to the rectification system for rectification to obtain trichlorosilane with high purity. The silicon powder at the bottom of the venturi forms slag slurry with part of the condensed chlorosilane, and the slag slurry is discharged to the slag slurry treatment device for separation of chlorosilane and treatment with alkali. In the above-mentioned cold hydrogenation process, the silicon powder carried out by trichlorosilane is directly treated as slag slurry, which not only increases the treatment cost, but also wastes resources.

[0004] In the existing cold hydrogenation production process, the gas phase after the fluidized bed reaction carries silicon powder, trichlorosilane, silicon tetrachloride, hydrogen and the heat of the fluidized bed. Trichlorosilane, silicon tetrachloride and hydrogen can be recycled in the subsequent system, but after multi-stage cooling, the silicon powder is mixed with high-boiling chlorosilane, which can only be treated as slag slurry, causing waste of silicon resources.

[0005] In the prior art, a double-flow state reaction system (publication number CN215855137U) in a cold hydrogenation process: a double-flow state reaction system is arranged, and a dispersed fluidized bed and a clustered fluidized bed are used in series. Although the silicon powder conversion rate of the device can be improved, the amount of silicon powder discharged from the dispersed fluidized bed is relatively small, and the reaction product and the reactant enter the clustered fluidized bed at the same time. The high concentration of the product affects the silicon powder conversion efficiency.

[0006] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, and therefore can include information that does not constitute prior art known to those skilled in the art. UTILITY MODEL CONTENT

[0007] The technical problem to be solved by the utility model is to provide a device for improving the conversion rate of cold hydrogenated silicon powder to solve the problems of the prior art.

[0008] In order to solve the above technical problems, the utility model discloses a device for improving the conversion rate of cold hydrogenated silicon powder, which comprises:

[0009] An external dust collector fluidly connected to the top outlet of the fluidized bed in the cold hydrogenation production process; the bottom outlet of the external dust collector is fluidly connected to the top inlet of the reactor;

[0010] The top outlet of the reactor is fluidly connected to the top inlet of the chlorosilane storage tank through the first heat exchange channel of the heat exchanger and the condensation channel of the condenser in sequence.

[0011] The top outlet of the chlorosilane storage tank is fluidly connected to the second heat exchange channel outlet of the heat exchanger and then fluidly connected to the bottom inlet of the reactor.

[0012] Further, the external dust collector comprises:

[0013] A bottom outlet fluidly connected to the top inlet of the reactor for inputting the carbon powder trapped by the external dust collector into the reactor top;

[0014] The external dust collector further comprises a top outlet fluidly connected to the downstream system for discharging the gas phase matter.

[0015] Further, the heat exchanger comprises:

[0016] The first heat exchange channel and the second heat exchange channel perform heat exchange.

[0017] The first heat exchange channel cools the matter output through the top outlet of the reactor;

[0018] The second heat exchange channel heats the hydrogen chloride gas.

[0019] Further, the top outlet of the chlorosilane storage tank is fluidly connected to the second heat exchange channel outlet of the heat exchanger for preheating the gas mixture therein.

[0020] Further, the condensation material of the condenser is circulating water.

[0021] Further, the chlorosilane storage tank is further provided with a bottom outlet for sending the liquid phase matter into the downstream rectification system.

[0022] Further, the reactor is a small-scale fluidized state reactor.

[0023] Further, the reactor is provided with a heat preservation device.

[0024] Further, the reactor is a fixed bed.

[0025] Further, a dust collector is arranged between the reactor and the heat exchanger.

[0026] Beneficial effects:

[0027] 1. In the utility model, the reactor is used for the reaction of hydrogen chloride and silicon powder, the reaction requires low temperature and pressure, the requirement for the reactor is low, and the safety is increased.

[0028] 2. In the utility model, the reactor is a fluidized reactor, the reaction is more sufficient, and the conversion rate is higher.

[0029] 3. In the utility model, the silicon powder in the tail gas is recovered and reacts with hydrogen chloride, the silicon powder and heat in the tail gas are effectively utilized, the conversion rate of the silicon powder is improved, and the treatment cost of the silicon residue slurry is reduced.

[0030] 4. In the utility model, the heat after the reaction is effectively utilized, and the energy waste is reduced.

[0031] 5. In the utility model, the gas phase of the chlorosilane storage tank returns to the hydrogen chloride inlet pipeline of the heat exchanger, the reuse of hydrogen chloride is realized, and the resource waste is reduced.

[0032] 6. The residue slurry generated by the cold hydrogenation device can be reduced by more than 80%, and the residue slurry treatment cost is greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0033] The above and / or other aspects of the utility model will become more apparent by the following detailed description in conjunction with the accompanying drawings and specific embodiments.

[0034] Figure 1 It is a general structure schematic view of the utility model.

[0035] Figure 2 It is a general structure schematic view of an embodiment.

[0036] In the drawing: 1 is a fluidized bed, 11 is a feeding port, 12 is an internal separator; 2 is an external dust collector; 3 is a reactor; 4 is a heat exchanger; 5 is a chlorosilane storage tank; 6 is a condenser. DETAILED DESCRIPTION

[0037] The general idea of the utility model is as follows:

[0038] The silicon powder contained in the gas phase of the fluidized bed outlet can be converted into chlorosilane by reacting with hydrogen chloride, and the heat carried by the silicon powder is utilized at the same time, the conversion efficiency of the silicon powder is improved, and the energy waste is reduced. The silicon powder in the gas phase outlet of the top of the fluidized bed is recovered, the heat in the gas phase is effectively utilized, the conversion rate of the silicon powder is improved, the resource waste is reduced, and energy saving and consumption reduction are realized.

[0039] The specific technical scheme of the utility model is as follows:

[0040] For example, Figure 1As shown, a device for improving the conversion rate of cold hydrogenated silicon powder is used in the gas phase produced after the reaction of the fluidized bed 1 in the cold hydrogenation production process. The fluidized bed 1 includes a feed inlet 11 at the bottom for receiving raw material substances such as silicon powder, STC, H2, and catalyst; the fluidized bed 1 also includes an internal separator 12 for preliminary dust removal; and a discharge outlet 13 at the top of the fluidized bed 1 for discharging gas phase substances.

[0041] The device includes an external dust collector 2 fluidly connected to the discharge outlet 13, from which the gas phase substances after dust removal are discharged from the top, and the trapped silicon powder is discharged from the bottom;

[0042] The bottom of the external dust collector 2 is connected to the top of a reactor 3 for transmitting silicon powder; in the reactor 3, silicon powder, silane gas, and hydrogen chloride react; the bottom input port of the reactor 3 is used to input a mixed gas of silane gas and hydrogen chloride, and the top is provided with an output port to output the generated gas phase chlorosilane and hydrogen chloride after reaction.

[0043] The top output port of the reactor 3 is connected to the first input port of a heat exchanger 4, and the output is from the first output port after heat exchange (cooling); the externally input hydrogen chloride is input from the second input port of the heat exchanger 4 and output from the second output port after heat exchange (heating).

[0044] The second output port of the heat exchanger 4 is connected to the input port of a condenser 6, and the output is from the output port after condensation.

[0045] The output port of the condenser 6 is fluidly connected to the top input port of a chlorosilane storage tank 5, the top output port of the chlorosilane storage tank 5 is mixed with the second output port of the heat exchanger 4 and connected to the bottom input port of the reactor 3; and the bottom output port of the chlorosilane storage tank 5 is connected to a downstream rectification system.

[0046] In use, silicon powder, STC, H2, and catalyst are fed through the bottom feed inlet 11 of the fluidized bed 1, the product gas phase trichlorosilane after heating reaction in the fluidized bed 1 is preliminarily dusted by the internal separator 12, and then a small amount of silicon powder, STC, and H2 are discharged from the top discharge outlet 13 of the fluidized bed, after dust removal by the external dust collector 2, the gas phase enters the downstream condensation rectification system, the silicon powder trapped by the external dust collector 2 enters the reactor 3 from the top of the reactor 3, the externally input hydrogen chloride is heated by the heat exchanger 4, mixed with the silane gas output from the top of the chlorosilane storage tank 5, and preheated before entering the reactor 3 from the bottom of the reactor 3 to react with the silicon powder, the gas phase chlorosilane and hydrogen chloride after reaction are discharged from the top of the reactor 3, enter the heat exchanger 4 for heat exchange (cooling), and then enter the condenser 6 for cooling by circulating water, the cooled material enters the chlorosilane storage tank, the gas phase at the top of the chlorosilane storage tank 5 returns to the heat exchanger hydrogen chloride outlet pipeline, and is mixed and used in the reactor 3. The liquid phase of the chlorosilane storage tank 5 is sent to the downstream rectification system.

[0047] The fluidized bed reaction temperature is 500-650 DEG C, the reaction pressure is 2.5-3.5 MPa, the reactor uses hydrogen chloride as the reaction raw material, the reaction temperature is 250-350 DEG C, and the reaction pressure is 0.1-0.4 MPa.

[0048] To sum up, in the technical scheme of the application, the reactor is used for the reaction of hydrogen chloride and silicon powder, the reaction requires low temperature and pressure, the requirement for the reactor is low, the safety is increased, the reactor is a fluidized bed reactor, the reaction is more complete, and the conversion rate is higher, the silicon powder in the tail gas is reacted with hydrogen chloride by the reactor, the silicon powder and heat in the tail gas are effectively utilized, the conversion rate of the silicon powder is improved, the treatment cost of the silicon slag slurry is reduced, the heat after the reaction is effectively utilized by the heat exchanger, the energy waste is reduced, the gaseous phase of the chlorosilane storage tank is returned to the hydrogen chloride inlet pipeline of the heat exchanger, the hydrogen chloride is recycled, and resource waste is reduced, and the slag slurry generated by the cold hydrogenation device can be reduced by more than 80%, and the treatment cost of the slag slurry is greatly reduced.

[0049] In another embodiment, the reactor is a fixed bed, and the silicon powder can also be recycled and utilized, and the conversion rate of the silicon powder is improved.

[0050] As shown in Figure 2 In another embodiment, a dust collector can be further arranged after the reactor to further remove other dust in the silicon powder.

[0051] The utility model provides a kind of thought and method of device for improving cold hydrogenation silicon powder conversion rate, and the method and approach of the technical scheme are many, above-mentioned only is the preferred embodiment of the utility model, it should be pointed out, for the ordinary skilled person in the art, without departing from the principle of the utility model, can make several improvements and refinements, these improvements and refinements also should be regarded as the protection scope of the utility model.The components not specified in the embodiment can be realized by prior art.

Claims

1. An apparatus for improving the conversion of cold hydrogenated silicon powder, characterized in that, The application relates to a production process of chlorosilane, which comprises the following steps: an external dust collector (2) is connected with the top outlet (13) of a fluidized bed (1) in the cold hydrogenation production process; the bottom outlet of the external dust collector (2) is connected with the top inlet of a reactor (3); the top outlet of the reactor (3) is sequentially connected with the first heat exchange channel of a heat exchanger (4) and the condensation channel of a condenser (6), and then connected with the top inlet of a chlorosilane storage tank (5); the top outlet of the chlorosilane storage tank (5) is connected with the second heat exchange channel outlet of the heat exchanger (4), and then connected with the bottom inlet of the reactor (3).

2. A device for improving the conversion of cold hydrogenated silicon powder according to claim 1, characterized in that, The external dust collector (2) comprises: a bottom outlet connected with the top inlet of the reactor (3), which is used for inputting the carbon powder intercepted by the external dust collector (2) into the top of the reactor (3); the external dust collector (2) further comprises a top outlet connected with a downstream system, which is used for discharging gas-phase substances.

3. The apparatus of claim 1, wherein, The heat exchanger (4) comprises: a first heat exchange channel and a second heat exchange channel for heat exchange; the first heat exchange channel is used for cooling the substances output from the top outlet of the reactor (3); the second heat exchange channel is used for heating the hydrogen chloride gas.

4. The apparatus of claim 1, wherein, The top outlet of the chlorosilane storage tank (5) is connected with the second heat exchange channel outlet of the heat exchanger (4), which is used for preheating the gas mixture therein.

5. The apparatus of claim 1, wherein, The condensation material of the condenser (6) is circulating water.

6. The apparatus of claim 1, wherein, The chlorosilane storage tank (5) is further provided with a bottom outlet, which is used for sending liquid-phase substances into a lower rectification system.

7. The apparatus of claim 1, wherein, The reactor (3) is a small-sized fluidized bed reactor.

8. The apparatus of claim 1, wherein, The reactor (3) is provided with a heat preservation device.

9. The apparatus of claim 1, wherein, The reactor (3) is a fixed bed.

10. The apparatus of claim 1, wherein, A dust collector is arranged between the reactor (3) and the heat exchanger (4).

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