CN212581530U - Silicon tetrachloride cold hydrogenation system - Google Patents
Silicon tetrachloride cold hydrogenation system Download PDFInfo
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- CN212581530U CN212581530U CN202021786071.6U CN202021786071U CN212581530U CN 212581530 U CN212581530 U CN 212581530U CN 202021786071 U CN202021786071 U CN 202021786071U CN 212581530 U CN212581530 U CN 212581530U
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Abstract
The utility model discloses a cold hydrogenation system of silicon tetrachloride. The silicon tetrachloride cold hydrogenation system comprises: a silicon tetrachloride evaporator; a mixed gas superheater; a gas-gas heat exchanger having a first syngas inlet and a first syngas outlet; a mixed gas heater; and a hydrogenation reactor, the hydrogenation reactor comprising: the body is provided with a reaction cavity, a silicon powder inlet, a fourth mixed gas inlet and a second synthesis gas outlet, and the second synthesis gas outlet is communicated with the first synthesis gas inlet; the gas distributor is arranged in the reaction cavity, is positioned between the fourth mixed gas inlet and the silicon powder inlet and is provided with a plurality of gas distribution holes; the nozzles are arranged in the gas distribution holes in a one-to-one correspondence mode, and an outlet of each nozzle faces upwards. According to the utility model discloses silicon tetrachloride cold hydrogenation system has that the energy consumption is low, the running cost is low, reaction conversion is high, hydrogenation reactor's export is difficult for advantages such as blockking up.
Description
Technical Field
The utility model relates to a silicon tetrachloride cold hydrogenation system.
Background
In the process of producing polysilicon by the modified siemens process, approximately 20 tons of silicon tetrachloride by-product are produced per 1 ton of polysilicon produced. A 2000 ton polysilicon plant produces 40000 tons of silicon tetrachloride each year. Silicon tetrachloride is liquid at normal temperature, and is not suitable for storage and transportation. Meanwhile, the market capacity of the silicon tetrachloride is limited, which causes the situation that the silicon tetrachloride is difficult to treat.
There are two mainstream techniques for treating silicon tetrachloride in the related art, wherein the silicon tetrachloride is mainly converted into trichlorosilane by a cold hydrogenation technique of silicon tetrachloride. In the technology, the main reactants are silicon tetrachloride, silicon powder and hydrogen, and the temperature is controlled to be between 450 and 500 ℃. Before the reaction, the hydrogen and the gaseous silicon tetrachloride need to be heated to a higher temperature, resulting in a higher heat consumption. Moreover, the reaction conversion rate is low and the dust content at the outlet of the hydrogenation reactor is high in the related technology.
SUMMERY OF THE UTILITY MODEL
The present invention aims at solving at least one of the technical problems in the related art to a certain extent. Therefore, the utility model provides a silicon tetrachloride cold hydrogenation system.
According to the utility model discloses a silicon tetrachloride cold hydrogenation system includes: the system comprises a silicon tetrachloride evaporator, a first hydrogen inlet and a first mixed gas outlet, wherein the silicon tetrachloride evaporator is provided with a silicon tetrachloride inlet, a first hydrogen inlet and a first mixed gas outlet; the mixed gas superheater is provided with 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; the gas-gas heat exchanger is provided with a second mixed gas inlet, a third mixed gas outlet, a first synthetic gas inlet and a first synthetic gas outlet, and the second mixed gas inlet is communicated with the second mixed gas outlet; the mixed gas heater is provided with a third mixed gas inlet and a fourth mixed gas outlet, and the third mixed gas inlet is communicated with the third mixed gas outlet; and a hydrogenation reactor, the hydrogenation reactor comprising: the reaction chamber is communicated with each of the silicon powder inlet, the fourth gas mixture inlet and the second synthesis gas outlet, the silicon powder inlet is positioned above the fourth gas mixture inlet, the second synthesis gas outlet is positioned above the silicon powder inlet, and the second synthesis gas outlet is communicated with the first synthesis gas inlet; the gas distributor is arranged in the reaction cavity, is positioned between the fourth mixed gas inlet and the silicon powder inlet in the vertical direction and is provided with a plurality of gas distribution holes; the nozzles are arranged in the gas distribution holes in a one-to-one correspondence mode, and an outlet of each nozzle faces upwards; and the cyclone separator is arranged in the reaction cavity, is positioned between the silicon powder inlet and the second synthetic gas outlet in the vertical direction, is adjacent to the second synthetic gas outlet in the vertical direction, is provided with a gas-solid mixture inlet, a solid outlet and a gas outlet, and is communicated with the second synthetic gas outlet.
According to the utility model discloses a silicon tetrachloride cold hydrogenation system 100 has the energy consumption and hangs down, the running cost is low, reaction conversion is high, the gas distribution hole of gas distributor 22 is difficult for blockking up, the advantage that the dust content of synthetic gas 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 discharge port located between the silicon powder inlet and the gas distributor in the up-down direction, the discharge port is adjacent to the gas distributor in the up-down direction, the diameter of the body is 2000mm to 5000mm, the height of the body is 16000mm to 30000mm, the nozzle is a straight nozzle or has a hood, and the hydrogenation reactor further includes: a Johnson mesh disposed within the reaction chamber, the Johnson mesh being located between the fourth mixture gas inlet and the gas distributor in an up-down direction; the foam breaking grid mesh is arranged in the reaction cavity and is positioned between the gas distributor and the silicon powder inlet in the vertical direction; the temperature sensors are arranged on the body at intervals along the vertical direction; and the pressure sensors are arranged on the body at intervals along the vertical direction, and the pressure sensors and the temperature sensors are opposite to each other in the radial direction of the body one by one.
Optionally, the cold hydrogenation system for silicon tetrachloride further comprises a venturi scrubber having a second syngas inlet, a third syngas outlet, a first condensate inlet, and a scrubbing liquid outlet, the second syngas inlet being in communication with the first syngas outlet.
Optionally, the silicon tetrachloride cold hydrogenation system further comprises a quenching tower, the quenching tower is provided with 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 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 scrubbing liquid inlet.
Optionally, the silicon tetrachloride cold hydrogenation system further comprises: the first-stage condenser is provided with a fourth synthesis gas inlet, a fifth synthesis gas outlet and a second condensate outlet, and the fourth synthesis gas inlet is communicated with the fourth synthesis gas outlet; the second-stage condenser is provided with 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 pressurization device having a second hydrogen inlet in communication with the first hydrogen outlet and a second hydrogen outlet in communication with the first hydrogen inlet; and a condensate collection tank having a second condensate inlet in communication with each of the second and third condensate outlets and a fourth condensate outlet in communication with the cooling medium inlet.
Optionally, the silicon tetrachloride cold hydrogenation system further comprises: the flash tank is provided with a slag slurry inlet, a gas phase outlet and a first liquid phase outlet, and the slag slurry inlet is communicated with the slag slurry outlet; the vacuum filter device is provided with 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, a filter layer is arranged in the vacuum filter device, the filter layer comprises filter cloth and a precoating layer arranged on the filter cloth, and the precoating layer is made of uniformly mixed chlorosilane and diatomite; a coarse product tank having a first filtrate inlet in communication with the first filtrate outlet; and a vacuum pump having a first gas inlet and a second gas outlet, the first gas inlet being in communication with the first gas outlet.
Optionally, the crude product tank has a second filtrate outlet, and the cold hydrogenation system for silicon tetrachloride further comprises: the concentrating tower is provided with a gas phase inlet, a second filtrate inlet, a chlorosilane outlet, a first waste gas outlet and a high-boiling residue outlet, the gas phase inlet is communicated with the gas phase outlet, and the second filtrate inlet is communicated with the second filtrate outlet; and the tail gas leaching tower is provided with a waste gas inlet, and the waste gas inlet is communicated with the first waste gas outlet.
Optionally, the silicon tetrachloride cold hydrogenation system further comprises: a buffer tank having a second liquid phase inlet in communication with the first liquid phase outlet and a second liquid phase outlet in communication with the first liquid phase inlet; the vacuum filter device comprises a precoating tank, a vacuum filter, a control device and a control device, wherein the precoating tank is provided with a precoating outlet, the vacuum filter is provided with a precoating inlet, and the precoating inlet is communicated with the precoating outlet; and the condenser is provided with a second gas inlet, a third gas outlet and a fourth gas outlet, the vacuum filtering device is provided with a carrier gas inlet, the second gas inlet is communicated with the second gas outlet, the third gas outlet is communicated with the carrier gas inlet, and the fourth gas outlet is communicated with the waste gas inlet.
Optionally, the cold hydrogenation system of silicon tetrachloride further includes the jar of hydrolysising, the jar of hydrolysising has second exhaust outlet, the import of high boiling thing raffinate and the import of solid filter residue, the import of high boiling thing raffinate with the export intercommunication of high boiling thing raffinate, the top of jar of hydrolysising is equipped with the shower, the exhaust gas import with second exhaust outlet intercommunication.
Drawings
Figure 1 is a schematic view of a partial structure of a silicon tetrachloride cold hydrogenation system according to an embodiment of the present invention;
figure 2 is a schematic view of a partial structure of a silicon tetrachloride cold hydrogenation system according to an embodiment of the present invention;
figure 3 is a schematic structural diagram of a hydrogenation reactor of a silicon tetrachloride cold hydrogenation system according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.
A silicon tetrachloride cold hydrogenation system 100 according to an embodiment of the present invention is described below with reference to the drawings. As shown in fig. 1-3, a silicon tetrachloride cold hydrogenation system 100 according to an embodiment of the present invention 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. The mixture superheater 12 has a first mixture inlet 121 and a second mixture outlet 122, and the first mixture inlet 121 communicates with the first mixture outlet 113. The gas-gas heat exchanger 13 has a second mixture inlet 131, a third mixture outlet 132, a first syngas inlet 133 and a first syngas outlet 134, the second mixture inlet 131 being in communication with the second mixture outlet 122. The mixture heater 14 has a third mixture inlet 141 and a fourth mixture outlet 142, and the third mixture inlet 141 communicates with the third mixture outlet 132.
The hydrogenation reactor 2 comprises 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 mixture inlet 213, and a second syngas outlet 214, each of the silicon powder inlet 212, the fourth mixture inlet 213, and the second syngas outlet 214 communicating with the reaction chamber 211. Silicon powder inlet 212 is located above fourth mixed gas inlet 213, and second syngas outlet 214 is located above silicon powder inlet 212, i.e. silicon powder inlet 212 is located between fourth mixed gas inlet 213 and second syngas outlet 214 in the up-down direction. The second syngas outlet 214 is in communication with the first syngas inlet 133.
The silicon powder, the hydrogen and the gaseous silicon tetrachloride react in the reaction cavity 211 of the hydrogenation reactor 2 to obtain high-temperature synthesis gas (trichlorosilane). According to the utility model discloses cold hydrogenation of silicon tetrachloride system 100 is through making second syngas export 214 and first syngas import 133 intercommunication to can utilize the syngas of high temperature to heat hydrogen and gaseous silicon tetrachloride's mist. Therefore, the energy consumption for heating the mixed gas can be reduced, and the operation cost of the silicon tetrachloride cold hydrogenation system 100 can be reduced.
According to the utility model discloses cold hydrogenation of silicon tetrachloride system 100 is through setting up gas distributor 22 between fourth mist import 213 and silicon powder import 212 to can make the mist of hydrogen and gaseous silicon tetrachloride distribute evenly on reaction chamber 211's cross section. Therefore, the mixed gas can be fully contacted with the silicon powder and the catalyst, dead zones are reduced, and the reaction conversion rate is improved.
According to the utility model discloses cold hydrogenation system of silicon tetrachloride 100 is through setting up nozzle 23 in gas distribution hole to avoid gas distributor 22's gas distribution hole (distribution punchhole) to be blockked up by the particulate matter, improve fluidization quality.
According to the utility model discloses silicon tetrachloride cold hydrogenation system 100 is through setting up cyclone 24 with second synthesis gas export 214 intercommunication to can reduce the dust content of this synthesis gas effectively, so that reduce the load of solid separator in low reaches effectively.
Therefore, the silicon tetrachloride cold hydrogenation system 100 according to the embodiment of the present invention has the advantages of low energy consumption, low operation cost, high reaction conversion rate, difficult blockage of the gas distribution holes of the gas distributor 22, low dust content of the synthesis gas, etc.
As shown in fig. 1-3, the silicon tetrachloride cold hydrogenation system 100 comprises 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 the silicon tetrachloride evaporator 11 through the silicon tetrachloride inlet 111, and hydrogen can enter the silicon tetrachloride evaporator 11 through the first hydrogen inlet 112. The hydrogen and the silicon tetrachloride can be heated by the steam, so that the consumption of electric energy can be reduced. Wherein, hydrogen can enter into silicon tetrachloride evaporimeter 11 from silicon tetrachloride evaporimeter 11's bottom uniformly, and hydrogen and silicon tetrachloride carry out the mixture of certain concentration, can adjust silicon tetrachloride's gasification temperature, reduce dirt thermal resistance simultaneously, improve heat exchange efficiency.
A mixed gas of hydrogen and gaseous silicon tetrachloride may leave the silicon tetrachloride evaporator 11 from a first mixed gas outlet 113.
The mixture superheater 12 has a first mixture inlet 121 and a second mixture outlet 122, and the first mixture inlet 121 communicates with the first mixture outlet 113. The mixture can thus enter the mixture superheater 12 from the first mixture inlet 121, and the mixture is further heated in the mixture superheater 12. The mixture gas superheater 12 may be an electric heater. The mixed gas exits the mixed gas superheater 12 from the second mixed gas outlet 122.
The gas-gas heat exchanger 13 has a second mixture inlet 131, a third mixture outlet 132, a first syngas inlet 133 and a first syngas outlet 134. The second mixture inlet 131 communicates with the second mixture outlet 122. Whereby the mixed gas can enter 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-gas heat exchanger 13 from the first synthesis gas inlet 133. Therefore, the high-temperature synthesis gas can be used for heating the mixed gas, so that the heat of the synthesis gas can be fully utilized for heating the mixed gas, the comprehensive utilization of energy is realized, and the energy consumption is reduced. The mixed gas exits the gas-gas heat exchanger 13 from the third mixed gas outlet 132.
The mixture heater 14 has a third mixture inlet 141 and a fourth mixture outlet 142, and the third mixture inlet 141 communicates with the third mixture outlet 132. The mixed gas is thus introduced into 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 mixture heater 14 is an electric heater. The mixed gas exits the mixed gas heater 14 from the fourth mixed gas outlet 142.
That is, the mixed gas passes through the mixed gas superheater 12, the gas-gas heat exchanger 13 and the mixed gas heater 14 in sequence, is heated to 500 ℃ to 850 ℃ in a stepwise manner, and then enters the hydrogenation reactor 2 for hydrogenation reaction.
The hydrogenation reactor 2 comprises a body 21, a gas distributor 22, a cyclone 24, a johnson mesh 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-30000 mm. The body 21 has a reaction chamber 211, a silicon powder inlet 212, a fourth mixture inlet 213, a discharge port 215, and a second syngas outlet 214. The mixed gas may be introduced into the reaction chamber 211 from the fourth mixed gas inlet 213. Discharge port 215 is located between silicon powder inlet 212 and gas distributor 22 in the up-down direction, and discharge port 215 is adjacent to gas distributor 22 in the up-down direction.
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. The mixed gas enters the reaction chamber 211 through the fourth mixed gas inlet 213, passes through the johnson screen 25, and is then sprayed upward through the plurality of nozzles 23, so that the mixed gas can be uniformly distributed over the cross-section of the reaction chamber 211. The nozzle 23 is a straight nozzle 23 or the nozzle 23 has a hood.
The mixture of silicon powder and catalyst can be delivered from silicon powder inlet 212 into reaction chamber 211 using a high pressure gas. The catalyst can be 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 produce synthesis gas (trichlorosilane). The foam breaking grid 26 is arranged in the reaction cavity 211, and the foam breaking grid 26 is positioned between the gas distributor 22 and the silicon powder inlet 212 in the vertical direction. The opening direction of the foam breaking grid mesh 26 is adjustable, and the foam breaking grid mesh 26 can effectively break mixed bubbles with larger size formed in the reaction process.
As shown in FIG. 3, a cyclone 24 is disposed in the reaction chamber 211, the cyclone 24 is located between the silicon powder inlet 212 and the second syngas outlet 214 in the up-down direction, and the cyclone 24 is adjacent to the second syngas outlet 214 in the up-down direction. The cyclone separator 24 has a gas-solids 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 react in the reaction cavity 211, a gas-solid mixture is obtained, which includes the synthesis gas and the solid material. The gas-solid mixture flows upwards and the average flow rate of the gas-solid mixture is reduced. The solids-solids mixture then enters the cyclone 24 along the solids-solids mixture inlet 241 (tangential inlet) of the cyclone 24. In the cyclone 24, the gas-solid mixture makes a downward spiral motion, passing through the cone section and the transition section of the cyclone 24 in sequence. After gas-solid separation is achieved, the syngas is discharged through the gas outlet and the second syngas outlet 214 in sequence. As mentioned above, the synthesis gas leaving the hydrogenation reactor 2 enters the gas-gas heat exchanger 13 to heat the mixed gas.
As shown in fig. 3, a plurality of temperature sensors 27 are provided on the body 21 at intervals in the up-down direction, and a plurality of pressure sensors 28 are provided on the body 21 at intervals in the up-down direction. The plurality of pressure sensors 28 and the plurality of temperature sensors 27 are opposed one by one in the radial direction of the body 21. That is, the number of the temperature sensors 27 and the number of the pressure sensors 28 may be equal, each of the temperature sensors 27 is opposed to one of the pressure sensors 28 in the radial direction of the body 21, and each of the pressure sensors 28 is opposed to one of the temperature sensors 27 in the radial direction of the body 21. The pressure and temperature at different locations of the hydrogenation reactor 2 can thus be detected and read. The vertical direction is shown by an arrow a in fig. 3.
As shown in fig. 1, the cold hydrogenation system 100 for silicon tetrachloride further comprises a venturi scrubber 3, the venturi scrubber 3 having a second syngas inlet 31, a third syngas outlet 32, a first condensate inlet 33 and a scrubbing liquid outlet 34. The second syngas inlet 31 is in communication with the first syngas outlet 134, and the syngas after heat exchange with the mixed gas enters the venturi scrubber 3 from the second syngas inlet 31. The synthesis gas entering the venturi scrubber 3 can thus be scrubbed with condensate entering the venturi scrubber 3 in order to remove the silicon powder particles from the synthesis gas, which enter the condensate. Wherein the synthesis gas leaving the gas-gas heat exchanger 13 has a temperature of about 200 ℃ to 350 ℃.
In the related technology, the silicon powder particles in the synthesis gas are removed by using a filtering mode, and the temperature and the pressure of the synthesis gas are very high, so the material requirement on the filter material of the filter is strict, the cost of the subcooler is high, the filter is easy to block, frequent cleaning and maintenance are needed, and the production is inconvenient. By removing the silicon powder particles in the synthesis gas by the Venturi scrubber 3, the silicon powder particles in the synthesis gas can be effectively removed, the synthesis gas can be cooled, and the requirements on equipment and the operation and maintenance frequency can be reduced.
As shown in fig. 1, the cold hydrogenation system 100 for silicon tetrachloride further comprises a quenching tower 4, wherein the quenching tower 4 is provided with a third synthesis gas inlet 41, a fourth synthesis gas outlet 42, a cooling medium inlet 43, a first condensate outlet 44, a scrubbing liquid inlet 45 and a slurry outlet 46.
The third syngas inlet 41 is in communication with the third syngas outlet 32 and the syngas exiting the venturi scrubber 3 enters the quench tower 4 from the third syngas inlet 41. The synthesis gas entering the quenching tower 4 is contacted with the condensate (liquid chlorosilane) for heat exchange so as to cool the synthesis gas to 120-160 ℃.
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 scrubbing liquid outlet 34 is in communication with a scrubbing liquid inlet 45, and scrubbing liquid (i.e., condensate containing the silicon powder particles) exiting the venturi scrubber 3 enters the quench tower 4 through the scrubbing liquid inlet 45.
As shown in fig. 1, the system 100 for cold hydrogenation of silicon tetrachloride further comprises a primary condenser 51, a secondary condenser 52, a pressurizing device 53 and a condensate collecting 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 syngas inlet 511 is in communication with the fourth syngas outlet 42, whereby the syngas exiting the quench tower 4 enters the first-stage condenser 51 from the fourth syngas inlet 511. The synthesis gas is condensed in a primary condenser 51 to obtain hydrogen and a condensate (liquid chlorosilane). The uncondensed syngas exits the primary condenser 51 at a 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 exiting the primary condenser 51 enters the secondary condenser 52 from a fifth syngas inlet 521. The synthesis gas is condensed in a secondary condenser 52 to obtain hydrogen and a condensate (liquid chlorosilanes). Hydrogen exits secondary condenser 52 from first hydrogen outlet 522 and condensate exits secondary condenser 52 from 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 communicating with the first hydrogen outlet 522, and the second hydrogen outlet 532 communicating with the first hydrogen inlet 112. The pressurizing device 53 pressurizes the hydrogen leaving the secondary condenser 52, and the pressurized hydrogen is conveyed to the silicon tetrachloride evaporator 11, so that the hydrogen can be recycled.
The condensate collection tank 54 has a second condensate inlet 541 and a fourth condensate outlet 542, the second condensate inlet 541 being in communication with each of the second condensate outlet 513 and the third condensate outlet 523. The condensate thus leaving the primary and secondary condensers 51, 52 enters a condensate collection tank 54. The fourth condensate outlet 542 is in communication with the cooling medium inlet 43, whereby condensate leaving the condensate collection canister 54 enters the quench tower 4 as cooling medium.
As shown in fig. 2, the cold hydrogenation system 100 for silicon tetrachloride further comprises a flash tank 61, a buffer tank 67, a pre-coating tank 68, a vacuum filtration device 62, a vacuum pump 64, a crude product tank 63 and a condenser 69.
The flash tank 61 has a slurry inlet in communication with the slurry outlet 46, a gas phase outlet 612 and a first liquid phase outlet 613. At the bottom of the quench tower 4 there is a slurry containing a significant amount of solid particles which exits the quench tower 4 at slurry outlet 46. The slurry leaving the quench tower 4 enters the flash tank 61 from a slurry inlet. The slurry is flashed in a flash tank 61 to obtain slurry (liquid phase) and chlorosilane (gas phase) with low boiling point, and the slurry obtained by flashing contains 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 flash resulting slurry (liquid phase) exits 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 filtering 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 is in communication with the first liquid phase inlet 622 whereby the slurry in the buffer tank 67 exits the buffer tank 67 from the second liquid phase outlet 672 and enters the vacuum filtration device 62 from the first liquid phase inlet 622. A filter layer is provided in the vacuum filter 62, and the filter layer includes a filter cloth and a precoat layer provided on the filter cloth, the precoat layer being made of uniformly mixed chlorosilane and diatomaceous earth.
The vacuum pump 64 has a first gas inlet 641 and a second gas outlet 642, the first gas inlet 641 being in communication with the first gas outlet 621. Before the filtration operation, the vacuum pump 64 is turned on to make the inside of the vacuum filtration apparatus 62 a negative pressure environment. The inside of the vacuum filter device 62 is negative pressure, nitrogen is introduced to the outside to maintain a certain pressure, and the solid-liquid separation is performed on the slurry by utilizing the pressure difference, so that filtrate and solid filter residue are obtained.
The raw product tank 63 has a first filtrate inlet 631, and the first filtrate inlet 631 communicates with the first filtrate outlet 623. The filtrate may thus exit the vacuum filtration device 62 from the first filtrate outlet 623 and enter the raw product tank 63 from the first filtrate inlet 631. The solid filter residue is scraped off by a scraper and conveyed to the hydrolysis tank 7.
The precoat tank 68 has a precoat outlet 681, and the vacuum filter 62 has a precoat inlet communicating with the precoat outlet 681. After chlorosilane and diatomaceous earth are uniformly mixed in the precoat tank 68, they are sent to the vacuum filter 62, where the precoat 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 through the second gas inlet 691. The gas exiting the vacuum pump 64 is condensed in a condenser 69 for further recovery of the useful components of the filtrate vapor.
The third gas outlet 692 is in communication with the carrier gas inlet 624 and the fourth gas outlet is in communication with the waste gas inlet 661. A part of the non-condensable gas is returned to the vacuum filtering device 62 as a carrier gas sequentially through the third gas outlet 692 and the carrier gas inlet 624, and the remaining part of the non-condensable gas is discharged to the off-gas eluting column 66 sequentially through the fourth gas outlet and the off-gas inlet 661.
As shown in fig. 2, the crude product tank 63 has a second filtrate outlet 632, and the cold hydrogenation system of silicon tetrachloride 100 further comprises a concentration tower 65 and a tail gas elution tower 66. The concentration tower 65 has a gas phase inlet 651, a second filtrate inlet 652, a chlorosilane outlet, a first off-gas outlet 654, and a high-boiling residue outlet 655.
A gas phase inlet 651 is in communication with the gas phase outlet 612, and low boiling chlorosilanes (gas phase) exit the flash tank 61 from the gas phase outlet 612, and enter the concentration tower 65 from the gas phase inlet 651. The second filtrate inlet 652 is communicated with the second filtrate outlet 632, and the filtrate in the crude product tank 63 sequentially passes through the second filtrate outlet 632 and the second filtrate inlet 652 and enters the concentration tower 65. The concentration column 65 has a bottom reboiler and an overhead condenser, and uses steam or heat transfer oil as a heat source. Chlorosilane rich in silicon tetrachloride is obtained at the top of the concentration tower 65, and high-boiling residue residual liquid at the bottom of the concentration tower 65 enters the hydrolysis tank 7.
The offgas scrubber 66 has an offgas inlet 661, and the offgas inlet 661 communicates with the first offgas outlet 654. The non-condensable gas in the concentrating tower 65 sequentially passes through the first waste gas outlet 654 and the waste gas inlet 661 to enter the off-gas eluting tower 66.
In the related technology, the slag slurry is treated by a direct hydrolysis method or a drying method, and the two methods have the advantages of low recovery rate, high comprehensive energy consumption, low product purity and large sewage quantity and bring great harm to the environment.
According to the utility model discloses cold hydrogenation system of silicon tetrachloride 100 is through setting up flash tank 61, vacuum filter 62 and concentrated tower 65 to can carry out the flash distillation, filter and concentrate to this sediment thick liquid, the rate of recovery of silicon tetrachloride in this sediment thick liquid can reach more than 99%, has improved silicon tetrachloride's rate of recovery and purity greatly, and the energy consumption is low, and the sewage volume is few.
As shown in FIG. 2, the cold hydrogenation system 100 for silicon tetrachloride further comprises a hydrolysis tank 7, wherein the hydrolysis tank 7 is provided with a second waste gas outlet, a high-boiling residue inlet 72 and a solid residue inlet 73.
As mentioned above, the solid residue may enter the hydrolysis tank 7 through the solid residue inlet 73. The high-boiling residue inlet 72 is communicated with the high-boiling residue outlet 655, and the high-boiling residue in the concentration tower 65 sequentially passes through the high-boiling residue outlet 655 and the high-boiling residue inlet 72 and enters the hydrolysis tank 7.
The solid filter residue and the high-boiling residue are reacted with alkali liquor in a hydrolysis tank 7 for hydrolysis so as to remove a small amount of chlorosilane components. As the hydrolysis reaction process can generate hydrogen chloride gas, in order to prevent the hydrogen chloride gas from entering a downstream device, a spray pipe is arranged at the top of the hydrolysis tank 7 so as to absorb the hydrogen chloride component in the discharged gas.
The waste gas inlet 661 is communicated with the second waste gas outlet so as to discharge the non-condensable gas in the hydrolysis tank 7 to the off-gas leaching tower 66. The wastewater in the hydrolysis tank 7 is discharged to a sewage treatment system.
In the description of the present invention, it is to 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", "radial", "circumferential", and the like, indicate the orientation or positional relationship indicated based on the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.
In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the present disclosure, the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer 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, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art without departing from the scope of the present invention.
Claims (10)
1. A silicon tetrachloride cold hydrogenation system is characterized by comprising:
the system comprises a silicon tetrachloride evaporator, a first hydrogen inlet and a first mixed gas outlet, wherein the silicon tetrachloride evaporator is provided with a silicon tetrachloride inlet, a first hydrogen inlet and a first mixed gas outlet;
the mixed gas superheater is provided with 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;
the gas-gas heat exchanger is provided with a second mixed gas inlet, a third mixed gas outlet, a first synthetic gas inlet and a first synthetic gas outlet, and the second mixed gas inlet is communicated with the second mixed gas outlet;
the mixed gas heater is provided with a third mixed gas inlet and a fourth mixed gas outlet, and the third mixed gas inlet is communicated with the third mixed gas outlet; and
a hydrogenation reactor, the hydrogenation reactor comprising:
the reaction chamber is communicated with each of the silicon powder inlet, the fourth gas mixture inlet and the second synthesis gas outlet, the silicon powder inlet is positioned above the fourth gas mixture inlet, the second synthesis gas outlet is positioned above the silicon powder inlet, and the second synthesis gas outlet is communicated with the first synthesis gas inlet;
the gas distributor is arranged in the reaction cavity, is positioned between the fourth mixed gas inlet and the silicon powder inlet in the vertical direction and is provided with a plurality of gas distribution holes;
the nozzles are arranged in the gas distribution holes in a one-to-one correspondence mode, and an outlet of each nozzle faces upwards; and
the cyclone separator is arranged in the reaction cavity, is positioned between the silicon powder inlet and the second synthetic gas outlet in the vertical direction, is adjacent to the second synthetic gas outlet in the vertical direction, and is provided with a gas-solid mixture inlet, a solid outlet and a gas outlet, and the gas outlet is communicated with the second synthetic gas outlet.
2. A cold hydrogenation system for silicon tetrachloride according to claim 1, wherein the mixed gas superheater is an electric heater and the mixed gas heater is an electric heater.
3. A silicon tetrachloride cold hydrogenation system according to claim 1, wherein the body has a discharge port between the silicon powder inlet and the gas distributor in the up-down direction, the discharge port is adjacent to the gas distributor in the up-down direction, the diameter of the body is 2000mm to 5000mm, the height of the body is 16000mm to 30000mm, the nozzle is a straight nozzle or the nozzle has a hood, and the hydrogenation reactor further comprises:
a Johnson mesh disposed within the reaction chamber, the Johnson mesh being located between the fourth mixture gas inlet and the gas distributor in an up-down direction;
the foam breaking grid mesh is arranged in the reaction cavity and is positioned between the gas distributor and the silicon powder inlet in the vertical direction;
the temperature sensors are arranged on the body at intervals along the vertical direction; and
the pressure sensors are arranged on the body at intervals along the vertical direction, and the pressure sensors and the temperature sensors are opposite to each other in the radial direction of the body.
4. A system for cold hydrogenation of silicon tetrachloride according to claim 1, further comprising a venturi scrubber having a second syngas inlet, a third syngas outlet, a first condensate inlet, and a scrubbing liquid outlet, the second syngas inlet in communication with the first syngas outlet.
5. A silicon tetrachloride cold hydrogenation system according to claim 4 further comprising a quench tower having a third syngas inlet, a fourth syngas outlet, a cooling medium inlet, a first condensate outlet, a scrub liquid inlet and a slurry outlet, the third syngas inlet communicating with the third syngas outlet, the first condensate outlet communicating with the first condensate inlet, the scrub liquid outlet communicating with the scrub liquid inlet.
6. A silicon tetrachloride cold hydrogenation system according to claim 5, further comprising:
the first-stage condenser is provided with a fourth synthesis gas inlet, a fifth synthesis gas outlet and a second condensate outlet, and the fourth synthesis gas inlet is communicated with the fourth synthesis gas outlet;
the second-stage condenser is provided with 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 pressurization device having a second hydrogen inlet in communication with the first hydrogen outlet and a second hydrogen outlet in communication with the first hydrogen inlet; and
a condensate collection canister having a second condensate inlet in communication with each of the second and third condensate outlets and a fourth condensate outlet in communication with the cooling medium inlet.
7. A silicon tetrachloride cold hydrogenation system according to claim 5, further comprising:
the flash tank is provided with a slag slurry inlet, a gas phase outlet and a first liquid phase outlet, and the slag slurry inlet is communicated with the slag slurry outlet;
the vacuum filter device is provided with 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, a filter layer is arranged in the vacuum filter device, the filter layer comprises filter cloth and a precoating layer arranged on the filter cloth, and the precoating layer is made of uniformly mixed chlorosilane and diatomite;
a coarse product tank having a first filtrate inlet in communication with the first filtrate outlet; and
a vacuum pump having a first gas inlet and a second gas outlet, the first gas inlet in communication with the first gas outlet.
8. A cold hydrogenation system of silicon tetrachloride according to claim 7, wherein the crude product tank has a second filtrate outlet, and the cold hydrogenation system of silicon tetrachloride further comprises:
the concentrating tower is provided with a gas phase inlet, a second filtrate inlet, a chlorosilane outlet, a first waste gas outlet and a high-boiling residue outlet, the gas phase inlet is communicated with the gas phase outlet, and the second filtrate inlet is communicated with the second filtrate outlet; and
and the tail gas leaching tower is provided with a waste gas inlet, and the waste gas inlet is communicated with the first waste gas outlet.
9. A silicon tetrachloride cold hydrogenation system according to claim 8, further comprising:
a buffer tank having a second liquid phase inlet in communication with the first liquid phase outlet and a second liquid phase outlet in communication with the first liquid phase inlet;
the vacuum filter device comprises a precoating tank, a vacuum filter, a control device and a control device, wherein the precoating tank is provided with a precoating outlet, the vacuum filter is provided with a precoating inlet, and the precoating inlet is communicated with the precoating outlet; and
the condenser is provided with a second gas inlet, a third gas outlet and a fourth gas outlet, the vacuum filtering device is provided with a carrier gas inlet, the second gas inlet is communicated with the second gas outlet, the third gas outlet is communicated with the carrier gas inlet, and the fourth gas outlet is communicated with the waste gas inlet.
10. The cold hydrogenation system of silicon tetrachloride according to claim 8, further comprising a hydrolysis tank, wherein the hydrolysis tank is provided with a second waste gas outlet, a high-boiling residue inlet and a solid residue inlet, the high-boiling residue inlet is communicated with the high-boiling residue outlet, a spray pipe is arranged at the top of the hydrolysis tank, and the waste gas inlet is communicated with the second waste gas outlet.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021786071.6U CN212581530U (en) | 2020-08-24 | 2020-08-24 | Silicon tetrachloride cold hydrogenation system |
| PCT/CN2021/081895 WO2022041699A1 (en) | 2020-08-24 | 2021-03-19 | Silicon tetrachloride cold hydrogenation system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202021786071.6U CN212581530U (en) | 2020-08-24 | 2020-08-24 | Silicon tetrachloride cold hydrogenation system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112158848A (en) * | 2020-08-24 | 2021-01-01 | 中国恩菲工程技术有限公司 | Silicon tetrachloride cold hydrogenation system |
| WO2022041699A1 (en) * | 2020-08-24 | 2022-03-03 | 中国恩菲工程技术有限公司 | Silicon tetrachloride cold hydrogenation system |
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2020
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112158848A (en) * | 2020-08-24 | 2021-01-01 | 中国恩菲工程技术有限公司 | Silicon tetrachloride cold hydrogenation system |
| WO2022041699A1 (en) * | 2020-08-24 | 2022-03-03 | 中国恩菲工程技术有限公司 | Silicon tetrachloride cold hydrogenation system |
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