WO2022041699A1

WO2022041699A1 - Silicon tetrachloride cold hydrogenation system

Info

Publication number: WO2022041699A1
Application number: PCT/CN2021/081895
Authority: WO
Inventors: 董丽萍; 张升学; 杨永亮; 石涛; 严大洲
Original assignee: 中国恩菲工程技术有限公司
Priority date: 2020-08-24
Filing date: 2021-03-19
Publication date: 2022-03-03

Abstract

A silicon tetrachloride cold hydrogenation system is provided. The system comprises a silicon tetrachloride evaporator, a gas mixture superheater, a gas-gas heat exchanger, a gas mixture heater and a hydrogenation reactor. The gas-gas heat exchanger has a first syngas inlet and a first syngas outlet. The hydrogenation reactor comprises a main body which has a reaction chamber, a silicon power inlet, a fourth gas mixture inlet and a second syngas outlet, the second syngas outlet being connected to the first syngas inlet. A gas distributor is arranged in the reaction chamber, is positioned between the fourth gas mixture inlet and the silicon powder inlet, and has multiple gas distribution holes. Multiple nozzles are arranged in the multiple gas distribution holes in a one-to-one manner, the outlet of each nozzle facing upwards. The system has advantages that energy consumption is low, operation cost is low, reaction conversion rate is high, the outlet of the hydrogenation reactor cannot be easily blocked, and the like.

Description

Silicon tetrachloride cold hydrogenation system

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority and rights of the Chinese patent applications with application number 202021786071.6 and application number 202010857628.9, the entire contents of the above Chinese patent applications are hereby incorporated by reference into this application.

technical field

The present application relates to the technical field of polysilicon production, in particular to a silicon tetrachloride cold hydrogenation system.

Background technique

In the process of producing polysilicon by the modified Siemens method, nearly 20 tons of silicon tetrachloride are produced as by-products for every 1 ton of polysilicon produced. A 2,000-ton polysilicon plant produces more than 40,000 tons of silicon tetrachloride annually. Silicon tetrachloride is liquid at room temperature and should not be stored and transported. At the same time, the market capacity of silicon tetrachloride is limited, which has created a difficult situation in the treatment of silicon tetrachloride.

There are two mainstream technologies in the related art to process silicon tetrachloride, the most important of which is to convert silicon tetrachloride into trichlorosilane through the cold hydrogenation technology of silicon tetrachloride. In this technology, the main reactants are silicon tetrachloride, silicon powder and hydrogen, and the temperature is controlled between 450-500 degrees. Before the reaction, hydrogen and gaseous silicon tetrachloride need to be heated to a higher temperature, resulting in a larger heat consumption. Moreover, in the related art, the reaction conversion rate is low, and the dust content at the outlet of the hydrogenation reactor is high.

SUMMARY OF THE INVENTION

The present application aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the embodiments of the present application propose a silicon tetrachloride cold hydrogenation system.

The silicon tetrachloride cold hydrogenation system according to the embodiment of the present application includes: a silicon tetrachloride evaporator, the silicon tetrachloride evaporator has a silicon tetrachloride inlet, a first hydrogen inlet and a first mixed gas outlet; the mixed gas a superheater, the mixed gas superheater has a first mixed gas inlet and a second mixed gas outlet, the first mixed gas inlet is communicated with the first mixed gas outlet; a gas-air heat exchanger, the gas-to-air exchange The heater has a second mixed gas inlet, a third mixed gas outlet, a first combined gas inlet and a first combined gas outlet, and the second mixed gas inlet is communicated with the second mixed gas outlet; the mixed gas heater, so The mixed gas heater has a third mixed gas inlet and a fourth mixed gas outlet, the third mixed gas inlet is communicated with the third mixed gas outlet; and a hydrogenation reactor, the hydrogenation reactor comprises: a body, the The body has a reaction chamber, a silicon powder inlet, a fourth mixed gas inlet, and a second synthesis gas outlet, each of the silicon powder inlet, the fourth mixed gas inlet, and the second synthesis gas outlet being associated with the the reaction chamber is communicated, the silicon powder inlet is located above the fourth mixed gas inlet, the second synthesis gas outlet is located above the silicon powder inlet, wherein the second synthesis gas outlet is connected to the first The synthesis gas inlet is in communication; a gas distributor is arranged in the reaction chamber, and the gas distributor is located between the fourth mixed gas inlet and the silicon powder inlet in the up-down direction, and the The gas distributor has a plurality of gas distribution holes; a plurality of nozzles, and the plurality of the nozzles are arranged in the plurality of the gas distribution holes in a one-to-one correspondence, and the outlet of each of the nozzles faces upward; and a cyclone separator, so The cyclone separator is arranged in the reaction chamber, the cyclone separator is located between the silicon powder inlet and the second synthesis gas outlet in the up-down direction, and the cyclone separator is adjacent to the above-mentioned cyclone in the up-down direction A second synthesis gas outlet, the cyclone has a gas-solid mixture inlet, a solids outlet and a gas outlet, the gas outlet communicating with the second synthesis gas outlet.

The silicon tetrachloride cold hydrogenation system 100 according to the embodiment of the present application has the advantages of low energy consumption, low operating cost, high reaction conversion rate, the gas distribution holes of the gas distributor 22 are not easily blocked, and the dust content of the syngas is low.

Optionally, the mixed gas superheater is an electric heater, and the mixed gas heater is an electric heater.

Optionally, the body has a relief port, the relief port is located between the silicon powder inlet and the gas distributor in the up-down direction, and the relief port is adjacent to the gas distribution in the up-down direction The diameter of the body is 2000mm-5000mm, the height of the body is 16000mm-30000mm, the nozzle is a straight-through nozzle or the nozzle has an air cap, and the hydrogenation reactor further comprises: Johnson net, the Johnson net The net is arranged in the reaction chamber, and the Johnson net is located between the fourth mixed gas inlet and the gas distributor in the up-down direction; the bubble breaking grid is arranged in the reaction chamber In the cavity, the foam-breaking grid is located between the gas distributor and the silicon powder inlet in the up-down direction; a plurality of temperature sensors are arranged on the body at intervals in the up-down direction; and a plurality of pressure sensors, the plurality of pressure sensors are arranged on the body at intervals in the up-down direction, and the plurality of the pressure sensors and the plurality of the temperature sensors are opposite to each other in the radial direction of the body.

Optionally, the silicon tetrachloride cold hydrogenation system further comprises a venturi scrubber, the venturi scrubber has a second syngas inlet, a third syngas outlet, a first condensate inlet and a scrubber outlet, so The second synthesis gas inlet communicates with the first synthesis gas outlet.

Optionally, the silicon tetrachloride cold hydrogenation system further comprises a quench tower, the quench tower has a third synthesis gas inlet, a fourth synthesis gas outlet, a cooling medium inlet, a first condensate outlet, a scrubbing liquid inlet and a slag inlet. A slurry outlet, the third synthesis gas inlet communicates with the third synthesis gas outlet, the first condensate outlet communicates with the first condensate inlet, and the scrubbing liquid outlet communicates with the scrubbing liquid inlet.

Optionally, the silicon tetrachloride cold hydrogenation system further comprises: a first-stage condenser, the first-stage condenser has a fourth synthesis gas inlet, a fifth synthesis gas outlet and a second condensate outlet, the fourth A synthesis gas inlet is communicated with the fourth synthesis gas outlet; a secondary condenser, the secondary condenser has a fifth synthesis gas inlet, a first hydrogen outlet and a third condensate outlet, and the fifth synthesis gas inlet is connected to The fifth synthesis gas outlet is in communication; a pressurizing device, the pressurizing device has a second hydrogen inlet and a second hydrogen outlet, the second hydrogen inlet is in communication with the first hydrogen outlet, and the second hydrogen outlet communicated with the first hydrogen inlet; and a condensate collection tank, the condensate collection tank has a second condensate inlet and a fourth condensate outlet, the second condensate inlet and the second condensate outlet and Each of the third condensate outlets is in communication and the fourth condensate outlet is in communication with the cooling medium inlet.

Optionally, the silicon tetrachloride cold hydrogenation system further comprises: a flash tank, the flash tank has a slurry inlet, a gas phase outlet and a first liquid phase outlet, the slurry inlet and the slurry outlet communication; a vacuum filter device, the vacuum filter device has a first gas outlet, a first liquid phase inlet and a first filtrate outlet, the first liquid phase inlet is communicated with the first liquid phase outlet, and the vacuum filter A filter layer is arranged in the device, and the filter layer includes a filter cloth and a precoat layer arranged on the filter cloth, and the precoat layer is made of uniformly mixed chlorosilane and diatomaceous earth; the crude product tank, the The crude product tank has a first filtrate inlet that communicates with the first filtrate outlet; and a vacuum pump, which has a first gas inlet and a second gas outlet, the first gas The inlet communicates with the first gas outlet.

Optionally, the crude product tank has a second filtrate outlet, and the silicon tetrachloride cold hydrogenation system further includes: a concentration tower, the concentration tower has a gas phase inlet, a second filtrate inlet, a chlorosilane outlet, a first an exhaust gas outlet and a high boiler residual liquid outlet, the gas phase inlet is communicated with the gas phase outlet, the second filtrate inlet is communicated with the second filtrate outlet; and a tail gas rinsing tower, the tail gas rinsing The tower has an exhaust gas inlet that communicates with the first exhaust gas outlet.

Optionally, the silicon tetrachloride cold hydrogenation system further comprises: a buffer tank, the buffer tank has a second liquid phase inlet and a second liquid phase outlet, the second liquid phase inlet is connected to the first liquid phase The outlet is communicated, and the second liquid phase outlet is communicated with the first liquid phase inlet; the pre-coating tank, the pre-coating tank has a pre-coating outlet, and the vacuum filtering device has a pre-coating inlet, and the pre-coating inlet is connected to the The precoat outlet is in communication; and a condenser, the condenser has a second gas inlet, a third gas outlet and a fourth gas outlet, the vacuum filter device has a carrier gas inlet, wherein the second gas inlet is connected to the The second gas outlet is in communication with the carrier gas inlet, the third gas outlet is in communication with the carrier gas inlet, and the fourth gas outlet is in communication with the exhaust gas inlet.

Optionally, the silicon tetrachloride cold hydrogenation system further includes a hydrolysis tank, and the hydrolysis tank has a second exhaust gas outlet, a high boiler raffinate inlet and a solid filter residue inlet, and the high boiler raffinate inlet is connected to the The high boiler residual liquid outlet is communicated, the top of the hydrolysis tank is provided with a spray pipe, and the waste gas inlet is communicated with the second waste gas outlet.

Description of drawings

Fig. 1 is the partial structure schematic diagram of the silicon tetrachloride cold hydrogenation system according to the embodiment of the present application;

Fig. 2 is the partial structure schematic diagram of the silicon tetrachloride cold hydrogenation system according to the embodiment of the present application;

3 is a schematic structural diagram of a hydrogenation reactor of a silicon tetrachloride cold hydrogenation system according to an embodiment of the present application.

detailed description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to be used to explain the present application, but should not be construed as a limitation to the present application.

The silicon tetrachloride cold hydrogenation system 100 according to the embodiment of the present application will be described below with reference to the accompanying drawings. As shown in FIGS. 1-3 , the silicon tetrachloride cold hydrogenation system 100 according to the embodiment of the present application includes a silicon tetrachloride evaporator 11 , a mixed gas superheater 12 , a gas-gas heat exchanger 13 , and a mixed gas heater 14 and hydrogenation reactor 2.

The silicon tetrachloride evaporator 11 has a silicon tetrachloride inlet 111 , a first hydrogen inlet 112 and a first mixed gas outlet 113 . The mixed gas superheater 12 has a first mixed gas inlet 121 and a second mixed gas outlet 122 , and the first mixed gas inlet 121 communicates with the first mixed gas outlet 113 . The gas-gas heat exchanger 13 has a second mixture inlet 131 , a third mixture outlet 132 , a first synthesis gas inlet 133 and a first synthesis gas outlet 134 , and the second mixture inlet 131 communicates with the second mixture outlet 122 . The mixed gas heater 14 has a third mixed gas inlet 141 and a fourth mixed gas outlet 142 , and the third mixed gas inlet 141 communicates with the third mixed gas outlet 132 .

The hydrogenation reactor 2 includes a body 21 , a gas distributor 22 , a cyclone 24 and a plurality of nozzles 23 . The body 21 has a reaction chamber 211 , a silicon powder inlet 212 , a fourth mixed gas inlet 213 and a second synthesis gas outlet 214 , each of the silicon powder inlet 212 , the fourth mixed gas inlet 213 and the second synthesis gas outlet 214 is connected to The reaction chamber 211 is in communication. The silicon powder inlet 212 is located above the fourth mixed gas inlet 213, and the second synthesis gas outlet 214 is located above the silicon powder inlet 212, that is, the silicon powder inlet 212 is located at the fourth mixed gas inlet 213 and the second synthesis gas outlet in the up-down direction. between 214. The second syngas outlet 214 communicates with the first syngas inlet 133 .

The gas distributor 22 is arranged in the reaction chamber 211, and the gas distributor 22 is located between the fourth mixed gas inlet 213 and the silicon powder inlet 212 in the up-down direction, and the gas distributor 22 has a plurality of gas distribution holes. The plurality of nozzles 23 are provided in the plurality of gas distribution holes in a one-to-one correspondence. In other words, the number of nozzles 23 may be equal to the number of gas distribution holes, and each gas distribution hole is provided with one nozzle 23 . The outlet of each nozzle 23 faces upwards. The cyclone separator 24 is arranged in the reaction chamber 211 , the cyclone separator 24 is located between the silicon powder inlet 212 and the second synthesis gas outlet 214 in the up-down direction, and the cyclone separator 24 is adjacent to the second synthesis gas outlet 214 in the up-down direction. The cyclone 24 has a gas-solid mixture inlet 241 , a solids outlet 242 and a gas outlet which communicates with the second syngas outlet 214 .

The silicon powder, hydrogen and gaseous silicon tetrachloride react in the reaction chamber 211 of the hydrogenation reactor 2 to obtain high-temperature synthesis gas (trichlorosilane). The silicon tetrachloride cold hydrogenation system 100 according to the embodiment of the present application makes the second synthesis gas outlet 214 communicate with the first synthesis gas inlet 133, so that the mixed gas of hydrogen and gaseous silicon tetrachloride can be heated by using the high temperature synthesis gas . As a result, the energy consumption for heating the mixed gas can be reduced, so that the operating cost of the silicon tetrachloride cold hydrogenation system 100 can be reduced.

According to the silicon tetrachloride cold hydrogenation system 100 according to the embodiment of the present application, the gas distributor 22 is arranged between the fourth mixed gas inlet 213 and the silicon powder inlet 212, so that the mixed gas of hydrogen and gaseous silicon tetrachloride can be The cross section of the reaction chamber 211 can be uniformly distributed. Thereby, the mixed gas can be fully contacted with the silicon powder and the catalyst, thereby reducing the dead space and improving the reaction conversion rate.

The silicon tetrachloride cold hydrogenation system 100 according to the embodiment of the present application disposes the nozzles 23 in the gas distribution holes, thereby preventing the gas distribution holes (distribution holes) of the gas distributor 22 from being blocked by particles and improving the fluidization quality.

The silicon tetrachloride cold hydrogenation system 100 according to the embodiment of the present application can effectively reduce the dust content of the synthesis gas by disposing the cyclone separator 24 in communication with the second synthesis gas outlet 214, so as to effectively reduce the downstream solid separation load of the device.

Therefore, the silicon tetrachloride cold hydrogenation system 100 according to the embodiment of the present application has the advantages of low energy consumption, low operation cost, high reaction conversion rate, the gas distribution holes of the gas distributor 22 are not easily blocked, and the dust content of the synthesis gas is low. .

As shown in FIGS. 1-3 , the silicon tetrachloride cold hydrogenation system 100 includes a silicon tetrachloride evaporator 11 , a mixed gas superheater 12 , a gas-gas heat exchanger 13 , a mixed gas heater 14 and a hydrogenation reactor 2 .

The silicon tetrachloride evaporator 11 has a silicon tetrachloride inlet 111 , a first hydrogen inlet 112 and a first mixed gas outlet 113 . Silicon tetrachloride can enter into the silicon tetrachloride evaporator 11 through the silicon tetrachloride inlet 111 , and hydrogen can enter into the silicon tetrachloride evaporator 11 through the first hydrogen inlet 112 . Hydrogen and silicon tetrachloride can be heated with steam, thereby reducing power consumption. Wherein, the hydrogen can enter into the silicon tetrachloride evaporator 11 uniformly from the bottom of the silicon tetrachloride evaporator 11, and the hydrogen and silicon tetrachloride are mixed with a certain concentration to adjust the vaporization temperature of the silicon tetrachloride, At the same time, the fouling thermal resistance is reduced and the heat exchange efficiency is improved.

The mixed gas of hydrogen and gaseous silicon tetrachloride can leave the silicon tetrachloride vaporizer 11 from the first mixed gas outlet 113 .

The mixed gas superheater 12 has a first mixed gas inlet 121 and a second mixed gas outlet 122 , and the first mixed gas inlet 121 communicates with the first mixed gas outlet 113 . As a result, the mixed gas can enter the mixed gas superheater 12 from the first mixed gas inlet 121 , and the mixed gas is further heated in the mixed gas superheater 12 . The gas mixture superheater 12 may be an electric heater. The mixed gas leaves the mixed gas superheater 12 from the second mixed gas outlet 122 .

The gas-gas heat exchanger 13 has a second mixed gas inlet 131 , a third mixed gas outlet 132 , a first synthesis gas inlet 133 and a first synthesis gas outlet 134 . The second mixed gas inlet 131 communicates with the second mixed gas outlet 122 . Therefore, the mixed gas can enter into the gas-gas heat exchanger 13 from the second mixed gas inlet 131 .

Since the first synthesis gas inlet 133 is communicated with the second synthesis gas outlet 214 of the hydrogenation reactor 2, the high-temperature synthesis gas (trichlorosilane) generated in the hydrogenation reactor 2 can enter the gas from the first synthesis gas inlet 133. gas heat exchanger 13. Thereby, the high-temperature synthesis gas can be used to heat the mixed gas, so that the heat of the synthesis gas can be fully utilized to heat the mixed gas, so as to realize comprehensive utilization of energy and reduce energy consumption. The mixed gas leaves the gas-gas heat exchanger 13 from the third mixed gas outlet 132 .

The mixed gas heater 14 has a third mixed gas inlet 141 and a fourth mixed gas outlet 142 , and the third mixed gas inlet 141 communicates with the third mixed gas outlet 132 . Thus, the mixed gas enters the mixed gas heater 14 from the third mixed gas inlet 141 , and the mixed gas is further heated in the mixed gas heater 14 . The air-fuel mixture heater 14 is an electric heater. The mixed gas leaves the mixed gas heater 14 from the fourth mixed gas outlet 142 .

That is to say, the mixed gas is successively heated to 500°C-850°C through the mixed gas superheater 12 , the gas-gas heat exchanger 13 and the mixed gas heater 14 , and then enters the hydrogenation reactor 2 for hydrogenation reaction.

The hydrogenation reactor 2 includes a body 21 , a gas distributor 22 , a cyclone 24 , a Johnson grid 25 , a bubble breaking grid 26 , a plurality of temperature sensors 27 , a plurality of pressure sensors 28 and a plurality of nozzles 23 . The diameter of the body 21 is 2000mm-5000mm, and the height of the body 21 is 16000mm-30000mm. The body 21 has a reaction chamber 211 , a silicon powder inlet 212 , a fourth mixed gas inlet 213 , a discharge port 215 and a second synthesis gas outlet 214 . The mixed gas can enter the reaction chamber 211 from the fourth mixed gas inlet 213 . The relief port 215 is located between the silicon powder inlet 212 and the gas distributor 22 in the up-down direction, and the relief port 215 is adjacent to the gas distributor 22 in the up-down direction.

The gas distributor 22 is arranged in the reaction chamber 211 , and the gas distributor 22 is located between the fourth mixed gas inlet 213 and the silicon powder inlet 212 in the up-down direction. The Johnson net 25 is arranged in the reaction chamber 211 , and the Johnson net 25 is located between the fourth mixed gas inlet 213 and the gas distributor 22 in the up-down direction. By setting the Johnson net 25, the accumulation of silicon powder can be effectively avoided.

The gas distributor 22 has a plurality of gas distribution holes. The plurality of nozzles 23 are provided in the plurality of gas distribution holes in a one-to-one correspondence. After the mixed gas enters the reaction chamber 211 from the fourth mixed gas inlet 213 , it first passes through the Johnson mesh 25 , and then is sprayed upward through a plurality of nozzles 23 , so that the mixed gas can be uniformly distributed on the cross section of the reaction chamber 211 . The nozzle 23 is a straight-through nozzle 23 or the nozzle 23 has a hood.

The mixture of silicon powder and catalyst can be transported from the silicon powder inlet 212 into the reaction chamber 211 by using high pressure gas. The catalyst can be a copper-nickel alloy, and the mass content of nickel in the copper-nickel alloy can be 10%-35%. The mixed gas and the mixture react in the reaction chamber 211 to generate synthesis gas (trichlorosilane). The bubble breaking grid 26 is arranged in the reaction chamber 211 , and the bubble breaking grid 26 is located between the gas distributor 22 and the silicon powder inlet 212 in the up-down direction. The opening direction of the bubble breaking grid 26 is adjustable, and the foam breaking grid 26 can effectively destroy the large-scale mixed bubbles formed in the reaction process.

As shown in FIG. 3 , the cyclone separator 24 is arranged in the reaction chamber 211, and the cyclone separator 24 is located between the silicon powder inlet 212 and the second synthesis gas outlet 214 in the vertical direction, and the cyclone separator 24 is adjacent to the first synthesis gas outlet 214 in the vertical direction. Two syngas outlets 214 . The cyclone 24 has a gas-solid mixture inlet 241 , a solids outlet 242 and a gas outlet which communicates with the second syngas outlet 214 .

After the mixed gas and the mixture are reacted in the reaction chamber 211, a gas-solid mixture is obtained, and the gas-solid mixture includes the synthesis gas and solid materials. The gas-solid mixture flows upward, and the average flow rate of the gas-solid mixture decreases. Then, the gas-solid mixture enters the cyclone separator 24 along the gas-solid mixture inlet 241 (tangential inlet) of the cyclone separator 24 . In the cyclone separator 24 , the gas-solid mixture performs a downward spiral motion and passes through the cone section and the transition section of the cyclone separator 24 in sequence. After the gas-solid separation is achieved, the synthesis gas is discharged through the gas outlet and the second synthesis gas outlet 214 in sequence. As described above, the synthesis gas leaving the hydrogenation reactor 2 enters the gas-to-gas heat exchanger 13 to heat the mixed gas.

As shown in FIG. 3 , the plurality of temperature sensors 27 are provided on the main body 21 at intervals in the up-down direction, and the plurality of pressure sensors 28 are provided in the main body 21 at intervals in the up-down direction. The plurality of pressure sensors 28 and the plurality of temperature sensors 27 face each other in the radial direction of the body 21 . That is to say, the number of temperature sensors 27 and the number of pressure sensors 28 may be equal, each temperature sensor 27 and one pressure sensor 28 are opposite to one pressure sensor 28 in the radial direction of the body 21 , and each pressure sensor 28 and one temperature sensor 27 are located in the body 21 . radially opposite. Thereby, the pressure and temperature at different positions of the hydrogenation reactor 2 can be detected and read. Among them, the up-down direction is shown by the arrow A in FIG. 3 .

As shown in FIG. 1 , the silicon tetrachloride cold hydrogenation system 100 further includes a venturi scrubber 3 having a second syngas inlet 31 , a third syngas outlet 32 , a first condensate inlet 33 and a scrubber Liquid outlet 34. The second synthesis gas inlet 31 is communicated with the first synthesis gas outlet 134 , and the synthesis gas after heat exchange with the mixed gas enters the venturi scrubber 3 from the second synthesis gas inlet 31 . Thereby, the syngas entering the venturi scrubber 3 can be scrubbed with the condensate entering the venturi scrubber 3 in order to remove the silicon powder particles in the syngas, the silicon powder particles entering the condensate in liquid. Therein, the temperature of the syngas leaving the gas-gas heat exchanger 13 is about 200°C-350°C.

In the related art, the silicon powder particles in the synthesis gas are removed by means of filtration. Because the temperature and pressure of the synthesis gas are very high, the material requirements for the filter material of the filter are strict, resulting in high cost of the subcooler, and filtration. The device is easy to block and requires frequent cleaning and maintenance, which is inconvenient for production. By using the venturi scrubber 3 to remove the silicon powder particles in the syngas, not only can the silicon powder particles in the syngas be effectively removed, but also the temperature of the syngas can be lowered, and the equipment requirements and operations can be reduced. Maintenance frequency.

As shown in FIG. 1, the silicon tetrachloride cold hydrogenation system 100 further includes a quench tower 4, and the quench tower 4 has a third synthesis gas inlet 41, a fourth synthesis gas outlet 42, a cooling medium inlet 43, a first condensate outlet 44, Washing liquid inlet 45 and slurry outlet 46.

The third synthesis gas inlet 41 communicates with the third synthesis gas outlet 32 , and the synthesis gas leaving the venturi scrubber 3 enters the quench tower 4 from the third synthesis gas inlet 41 . The syngas entering the quench tower 4 is contacted with the condensate (liquid chlorosilane) for heat exchange, so as to cool the syngas to 120°C-160°C.

The first condensate outlet 44 communicates with the first condensate inlet 33 , and the condensate leaving the quench tower 4 enters the venturi scrubber 3 from the first condensate inlet 33 . The washing liquid outlet 34 communicates with the washing liquid inlet 45 , and the washing liquid leaving the venturi scrubber 3 (ie, the condensate containing the silicon powder particles) enters the quenching tower 4 from the washing liquid inlet 45 .

As shown in FIG. 1 , the silicon tetrachloride cold hydrogenation system 100 further includes a primary condenser 51 , a secondary condenser 52 , a pressurizing device 53 and a condensate collection tank 54 . The primary condenser 51 has a fourth syngas inlet 511 , a fifth syngas outlet 512 and a second condensate outlet 513 . The fourth synthesis gas inlet 511 communicates with the fourth synthesis gas outlet 42 , whereby the synthesis gas leaving the quench tower 4 enters the primary condenser 51 from the fourth synthesis gas inlet 511 . The syngas is condensed in the primary condenser 51 to obtain hydrogen gas and a condensate (liquid chlorosilane). The uncondensed syngas leaves the primary condenser 51 from the fifth syngas outlet 512 .

The secondary condenser 6952 has a fifth synthesis gas inlet 521 , a first hydrogen outlet 522 and a third condensate outlet 523 , and the fifth synthesis gas inlet 521 communicates with the fifth synthesis gas outlet 512 . The syngas leaving the primary condenser 51 enters the secondary condenser 52 from the fifth syngas inlet 521 . The syngas is condensed in a secondary condenser 52 to obtain hydrogen gas and a condensate (liquid chlorosilane). Hydrogen leaves the secondary condenser 52 from the first hydrogen outlet 522, and condensate leaves the secondary condenser 52 from the third condensate outlet 523.

The pressurizing device 53 has a second hydrogen inlet 531 and a second hydrogen outlet 532 , the second hydrogen inlet 531 communicates with the first hydrogen outlet 522 , and the second hydrogen outlet 532 communicates with the first hydrogen inlet 112 . In this way, the pressurizing device 53 pressurizes the hydrogen gas leaving the secondary condenser 52, so that the pressurized hydrogen gas is transported into the silicon tetrachloride evaporator 11, so as to realize the recycling use of the hydrogen gas.

The condensate collection tank 54 has a second condensate inlet 541 and a fourth condensate outlet 542 communicating with each of the second condensate outlet 513 and the third condensate outlet 523 . Thereby, the condensate leaving the primary condenser 51 and the secondary condenser 52 enters the condensate collection tank 54 . The fourth condensate outlet 542 is communicated with the cooling medium inlet 43, whereby the condensate leaving the condensate collecting tank 54 enters the quenching tower 4 as a cooling medium.

As shown in FIG. 2 , the silicon tetrachloride cold hydrogenation system 100 further includes a flash tank 61 , a buffer tank 67 , a precoat tank 68 , a vacuum filter device 62 , a vacuum pump 64 , a crude product tank 63 and a condenser 69 .

The flash tank 61 has a slurry inlet, a gas phase outlet 612 and a first liquid phase outlet 613 , and the slurry inlet communicates with the slurry outlet 46 . At the bottom of the quench tower 4 there is a slurry containing a large amount of solid particles which leaves the quench tower 4 from the slurry outlet 46 . The slurry leaving the quench tower 4 enters the flash tank 61 from the slurry inlet. The slurry is flashed in a flash tank 61 to obtain a slurry (liquid phase) and a low-boiling chlorosilane (gas phase), the resulting slurry containing silicon tetrachloride and solid particles.

The buffer tank 67 has a second liquid phase inlet 671 and a second liquid phase outlet 672 . The second liquid phase inlet 671 communicates with the first liquid phase outlet 613 . The slurry (liquid phase) obtained by flashing leaves the flash tank 61 from the first liquid phase outlet 613 and enters the buffer tank 67 from the second liquid phase inlet 671 .

The vacuum filter device 62 has a first gas outlet 621 , a first liquid phase inlet 622 and a first filtrate outlet 623 . The second liquid phase outlet 672 communicates with the first liquid phase inlet 622 , so that the slurry in the buffer tank 67 leaves the buffer tank 67 from the second liquid phase outlet 672 and enters the vacuum filtration device from the first liquid phase inlet 622 within 62. The vacuum filter device 62 is provided with a filter layer, and the filter layer includes a filter cloth and a pre-coat layer provided on the filter cloth, and the pre-coat layer is made of uniformly mixed chlorosilane and diatomaceous earth.

The vacuum pump 64 has a first gas inlet 641 and a second gas outlet 642 , and the first gas inlet 641 communicates with the first gas outlet 621 . Before the filtration operation, turn on the vacuum pump 64 to make the inside of the vacuum filtration device 62 a negative pressure environment. The inside of the vacuum filtration device 62 is under negative pressure, and nitrogen is introduced into the outside to maintain a certain pressure, and the slurry is separated into solid and liquid by means of the pressure difference, so as to obtain filtrate and solid filter residue.

The crude product tank 63 has a first filtrate inlet 631 that communicates with the first filtrate outlet 623 . Thus, the filtrate can leave the vacuum filtration device 62 from the first filtrate outlet 623 and enter the crude product tank 63 from the first filtrate inlet 631 . The solid filter residue is scraped off by a scraper and sent to the hydrolysis tank 7 .

The precoat tank 68 has a precoat outlet 681, and the vacuum filter device 62 has a precoat inlet which communicates with the precoat outlet 681. After the chlorosilane and diatomaceous earth are mixed uniformly in the precoating tank 68, they are sent to the vacuum filtration device 62, and the precoating layer is formed on the filter cloth.

The condenser 69 has a second gas inlet 691 , a third gas outlet 692 and a fourth gas outlet, and the vacuum filter device 62 has a carrier gas inlet 624 . The second gas inlet 691 communicates with the second gas outlet 642 , and the gas discharged from the vacuum pump 64 enters the condenser 69 from the second gas inlet 691 . The gas discharged from the vacuum pump 64 is condensed in the condenser 69 for further recovery of useful components in the filtrate vapor.

The third gas outlet 692 communicates with the carrier gas inlet 624 , and the fourth gas outlet communicates with the exhaust gas inlet 661 . As a result, a part of the non-condensable gas is returned to the vacuum filter device 62 as a carrier gas through the third gas outlet 692 and the carrier gas inlet 624 in sequence, and the rest of the non-condensable gas is discharged to the exhaust gas rinsing through the fourth gas outlet and the exhaust gas inlet 661 in sequence. Tower 66.

As shown in FIG. 2 , the crude product tank 63 has a second filtrate outlet 632 , and the silicon tetrachloride cold hydrogenation system 100 further includes a concentration tower 65 and a tail gas washing tower 66 . The concentration tower 65 has a gas phase inlet 651 , a second filtrate inlet 652 , a chlorosilane outlet, a first waste gas outlet 654 and a high boiler raffinate outlet 655 .

The gas phase inlet 651 is communicated with the gas phase outlet 612 , the low boiling point chlorosilane (gas phase) leaves the flash tank 61 from the gas phase outlet 612 , and the chlorosilane enters the concentration tower 65 from the gas phase inlet 651 . The second filtrate inlet 652 communicates with the second filtrate outlet 632 , and the filtrate in the crude product tank 63 enters the concentration tower 65 through the second filtrate outlet 632 and the second filtrate inlet 652 in sequence. The concentration tower 65 has a bottom reboiler and an overhead condenser, and uses steam or heat transfer oil as a heat source. The tower top of the concentration tower 65 obtains the chlorosilane rich in silicon tetrachloride, and the high boiler raffinate of the tower kettle of the concentration tower 65 enters the hydrolysis tank 7.

The exhaust gas washing tower 66 has an exhaust gas inlet 661 , and the exhaust gas inlet 661 communicates with the first exhaust gas outlet 654 . The non-condensable gas in the concentration tower 65 enters the tail gas washing tower 66 through the first exhaust gas outlet 654 and the exhaust gas inlet 661 in sequence.

The related art uses direct hydrolysis or drying to process the slurry, which either have low recovery rate, high comprehensive energy consumption, low product purity and large amount of sewage, which bring great harm to the environment.

The silicon tetrachloride cold hydrogenation system 100 according to the embodiment of the present application is provided with a flash tank 61, a vacuum filtration device 62 and a concentration tower 65, so that the slurry can be flashed, filtered and concentrated. The recovery rate of silicon chloride can reach more than 99%, which greatly improves the recovery rate and purity of silicon tetrachloride, and has low energy consumption and less sewage.

As shown in FIG. 2 , the silicon tetrachloride cold hydrogenation system 100 further includes a hydrolysis tank 7 , and the hydrolysis tank 7 has a second exhaust gas outlet, a high boiler residual liquid inlet 72 and a solid filter residue inlet 73 .

As mentioned above, the solid filter residue can enter the hydrolysis tank 7 through the solid filter residue inlet 73 . The high-boiler raffinate inlet 72 is communicated with the high-boiler raffinate outlet 655, and the high-boiler raffinate in the concentration tower 65 enters the hydrolysis tank 7 through the high-boiler raffinate outlet 655 and the high-boiler raffinate inlet 72 successively. .

The solid filter residue and the high boiler residue are reacted with alkali solution in the hydrolysis tank 7 for hydrolysis, so as to remove a small amount of chlorosilane components. Since hydrogen chloride gas will be generated during the hydrolysis reaction, in order to prevent the hydrogen chloride gas from entering the downstream device, a spray pipe is arranged on the top of the hydrolysis tank 7 to absorb the hydrogen chloride component in the exhaust gas.

The exhaust gas inlet 661 is communicated with the second exhaust gas outlet, so as to discharge the non-condensable gas in the hydrolysis tank 7 to the exhaust gas washing tower 66 . The waste water in the hydrolysis tank 7 is discharged to the sewage treatment system.

In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " Rear, Left, Right, Vertical, Horizontal, Top, Bottom, Inner, Outer, Clockwise, Counterclockwise, Axial, The orientations or positional relationships indicated by "radial direction", "circumferential direction", etc. are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying the indicated devices or elements. It must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as a limitation of the present application.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless expressly and specifically defined otherwise.

In this application, unless otherwise expressly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrated; it can be a mechanical connection or an electrical connection or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two components or the interaction relationship between the two components, unless otherwise expressly qualified. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

In this application, unless otherwise expressly stated and defined, a first feature "on" or "under" a second feature may be in direct contact with the first and second features, or the first and second features indirectly through an intermediary touch. Also, the first feature being "above", "over" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., mean the specific features, structures, materials, or characteristics described in connection with the embodiment or example. Features are included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations to the present application. Embodiments are subject to variations, modifications, substitutions and variations.

Claims

A silicon tetrachloride cold hydrogenation system, characterized in that, comprising:

A silicon tetrachloride evaporator, the silicon tetrachloride evaporator has a silicon tetrachloride inlet, a first hydrogen inlet and a first mixed gas outlet;

a mixed gas superheater, the mixed gas superheater has a first mixed gas inlet and a second mixed gas outlet, and the first mixed gas inlet is communicated with the first mixed gas outlet;

A gas-to-gas heat exchanger, the gas-to-gas heat exchanger has a second mixed gas inlet, a third mixed gas outlet, a first synthesis gas inlet and a first synthesis gas outlet, the second mixed gas inlet and the second mixed gas inlet The mixed gas outlet is connected;

a mixed gas heater having a third mixed gas inlet and a fourth mixed gas outlet, the third mixed gas inlet being in communication with the third mixed gas outlet; and

A hydrogenation reactor, the hydrogenation reactor comprising:

a body having a reaction chamber, a silicon powder inlet, a fourth mixture inlet and a second synthesis gas outlet, each of the silicon powder inlet, the fourth mixture inlet and the second synthesis gas outlet The first one is in communication with the reaction chamber, the silicon powder inlet is located above the fourth mixed gas inlet, and the second synthesis gas outlet is located above the silicon powder inlet, wherein the second synthesis gas outlet is connected to the the first synthesis gas inlet is communicated;

A gas distributor, the gas distributor is arranged in the reaction chamber, the gas distributor is located between the fourth mixed gas inlet and the silicon powder inlet in the up-down direction, and the gas distributor has multiple gas distribution holes;

a plurality of nozzles, the nozzles are disposed in the gas distribution holes in a one-to-one correspondence, and the outlet of each of the nozzles faces upward; and

A cyclone separator, the cyclone separator is arranged in the reaction chamber, the cyclone separator is located between the silicon powder inlet and the second synthesis gas outlet in the up-down direction, and the cyclone separator is up and down Directionally adjacent to the second syngas outlet, the cyclone has a gas-solid mixture inlet, a solids outlet, and a gas outlet, the gas outlet communicating with the second syngas outlet.
The silicon tetrachloride cold hydrogenation system according to claim 1, wherein the gas mixture superheater is an electric heater, and the gas mixture heater is an electric heater.
The silicon tetrachloride cold hydrogenation system according to claim 1 or 2, wherein the main body has a relief port, and the relief port is located between the silicon powder inlet and the gas distributor in the up-down direction. In between, the discharge port is adjacent to the gas distributor in the up-down direction, the diameter of the body is 2000mm-5000mm, the height of the body is 16000mm-30000mm, and the nozzle is a straight-through nozzle or the nozzle Having a hood, the hydrogenation reactor further comprises:

Johnson net, the Johnson net is arranged in the reaction chamber, and the Johnson net is located between the fourth mixed gas inlet and the gas distributor in the up-down direction;

a foam breaking grid, the foam breaking grid is arranged in the reaction chamber, and the foam breaking grid is located between the gas distributor and the silicon powder inlet in the up-down direction;

a plurality of temperature sensors, the plurality of temperature sensors are provided on the body at intervals in the up-down direction; and

A plurality of pressure sensors, the plurality of pressure sensors are arranged on the main body at intervals along the up-down direction, and the plurality of the pressure sensors and the plurality of the temperature sensors face each other in the radial direction of the main body.
The silicon tetrachloride cold hydrogenation system according to any one of claims 1-3, further comprising a venturi scrubber having a second synthesis gas inlet and a third synthesis gas outlet , a first condensate inlet and a scrubbing liquid outlet, and the second synthesis gas inlet communicates with the first synthesis gas outlet.
The silicon tetrachloride cold hydrogenation system according to claim 4, characterized in that, further comprising a quenching tower, the quenching tower has a third synthesis gas inlet, a fourth synthesis gas outlet, a cooling medium inlet, and a first condensate outlet , a scrubbing liquid inlet and a slurry outlet, the third synthesis gas inlet is communicated with the third synthesis gas outlet, the first condensate outlet is communicated with the first condensate inlet, and the scrubbing liquid outlet is communicated with the third synthesis gas outlet. The washing liquid inlet is connected.
Silicon tetrachloride cold hydrogenation system according to claim 5, is characterized in that, further comprises:

a primary condenser, the primary condenser has a fourth synthesis gas inlet, a fifth synthesis gas outlet and a second condensate outlet, the fourth synthesis gas inlet is communicated with the fourth synthesis gas outlet;

a secondary condenser, the secondary condenser has a fifth synthesis gas inlet, a first hydrogen outlet and a third condensate outlet, and the fifth synthesis gas inlet is communicated with the fifth synthesis gas outlet;

a pressurizing device, the pressurizing device has a second hydrogen inlet and a second hydrogen outlet, the second hydrogen inlet is communicated with the first hydrogen outlet, and the second hydrogen outlet is communicated with the first hydrogen inlet; and

A condensate collection tank, the condensate collection tank has a second condensate inlet and a fourth condensate outlet, the second condensate inlet and each of the second condensate outlet and the third condensate outlet; One is in communication, and the fourth condensate outlet is in communication with the cooling medium inlet.
Silicon tetrachloride cold hydrogenation system according to claim 5 or 6, is characterized in that, further comprises:

a flash tank, the flash tank has a slurry inlet, a gas phase outlet and a first liquid phase outlet, and the slurry inlet is communicated with the slurry outlet;

A vacuum filter device, the vacuum filter device has a first gas outlet, a first liquid phase inlet and a first filtrate outlet, the first liquid phase inlet is communicated with the first liquid phase outlet, and the inside of the vacuum filter device A filter layer is provided, the filter layer includes a filter cloth and a precoat layer arranged on the filter cloth, and the precoat layer is made of uniformly mixed chlorosilane and diatomaceous earth;

a crude product tank having a first filtrate inlet in communication with the first filtrate outlet; and

The vacuum pump has a first gas inlet and a second gas outlet, and the first gas inlet communicates with the first gas outlet.
The silicon tetrachloride cold hydrogenation system according to claim 7, wherein the crude product tank has a second filtrate outlet, and the silicon tetrachloride cold hydrogenation system further comprises:

A concentration tower, the concentration tower has a gas phase inlet, a second filtrate inlet, a chlorosilane outlet, a first waste gas outlet and a high boiler raffinate outlet, the gas phase inlet is communicated with the gas phase outlet, and the second filtrate the inlet is in communication with the second filtrate outlet; and

The tail gas washing tower has an exhaust gas inlet, and the exhaust gas inlet is communicated with the first exhaust gas outlet.
Silicon tetrachloride cold hydrogenation system according to claim 8, is characterized in that, further comprises:

a buffer tank, the buffer tank has a second liquid-phase inlet and a second liquid-phase outlet, the second liquid-phase inlet is communicated with the first liquid-phase outlet, and the second liquid-phase outlet is connected with the first liquid-phase outlet connected to the inlet;

a pre-coating tank having a pre-coating outlet, the vacuum filtering device having a pre-coating inlet communicating with the pre-coating outlet; and

A condenser, the condenser has a second gas inlet, a third gas outlet and a fourth gas outlet, the vacuum filter device has a carrier gas inlet, wherein the second gas inlet is communicated with the second gas outlet, so The third gas outlet communicates with the carrier gas inlet, and the fourth gas outlet communicates with the exhaust gas inlet.
The silicon tetrachloride cold hydrogenation system according to claim 8 or 9, further comprising a hydrolysis tank, the hydrolysis tank has a second exhaust gas outlet, a high boiler residual liquid inlet and a solid filter residue inlet, the high boiler The boiler residue inlet is communicated with the high boiler residue outlet, the top of the hydrolysis tank is provided with a spray pipe, and the waste gas inlet is communicated with the second waste gas outlet.