TWI681817B - Fluidized bed reactor for composing trichlorosilane - Google Patents

Abstract

A fluidized bed reactor for synthesizing trichlorosilane includes: a reactor setting an internal space in which that metal grade silicon reacts with feed gas to produce trichlorosilane gas by a hydrochlorination reaction and a direct chlorination reaction; a cyclone capturing fine particles micronized from the metal grade silicon to rise in the internal space of the reactor; a bypass line connected to the reactor so as to discharge the fine particles to the outside of the reactor; a bypass valve provided in the bypass line; and a separator connected to the bypass valve to separate and treat the fine particles from discharge gas discharged from the reactor.

Description

Fluidized bed reactor for synthesizing trichlorosilane

The invention provides a fluidized bed reactor for synthesizing trichlorosilane, which can use metallurgical grade silicon and generate trichlorosilane gas through hydrochlorination reaction and direct chlorination reaction.

In the known technology, when metallurgical grade silicon has a purity of 98% to 99%, it can be subjected to hydrochlorination reaction and direct chlorination reaction to produce trichlorosilane. Using Siemens chemical vapor deposition reaction (Siemens chemical vapor deposition reaction), trichlorosilane is used to produce high-purity polycrystalline silicon with a purity of 9N to 11N or higher.

Fluidized bed reactors can be used to synthesize trichlorosilane gas. The fluidized bed reactor has the advantages of being able to use the flow of particles to keep the internal temperature constant and to increase the yield by increasing the contact between solids and gases. However, the fluidized bed reactor has the disadvantage that it is not easy to operate and maintain.

When the metallurgical grade silicon and the feed gas complete the reaction in the reactor, trichlorosilane is produced. At this point, metallurgical grade silicon will be micronized with time and accumulate in the reactor.

A small amount of fine particles has a positive effect on the smooth flow characteristics of metallurgical grade silicon in the reactor, but when excessive accumulation of fine particles, channeling or slugging may occur.

When the phenomenon of channel flow or plug flow occurs, the contact efficiency between gas and solid will decrease, which will have a negative effect on the reactivity. Furthermore, when fine particles that are not reactive accumulate in the reactor, the yield of trichlorosilane will cause problems.

In this regard, it is necessary to remove fine particles accumulated in the reactor. However, due to the characteristic of the reactor that the feed gas is injected from the lower part of the reactor, the fine particles with small size will be lifted to the upper part of the reactor and collected again by the cyclone separator, and then by the feeder ( dipleg) Return to the reactor.

A small amount of fine particles not collected by the reactor will be discharged out of the reactor, but the amount of fine particles discharged from the reactor will be smaller than the amount of fine particles accumulated in the reactor. That is to say, because fine particles will accumulate in the reactor, the longer the operating time of the reactor, the worse the stability of the fluidized bed reactor.

Therefore, in order to remove the fine particles accumulated in the reactor, it is necessary to stop the operation of the fluidized bed reactor, resulting in a decrease in productivity and economic loss. In order to be able to remove the fine particles while avoiding the above-mentioned losses, in addition to the cyclone, it is necessary to additionally provide a device for discharging and controlling the fine particles and a device for separating and processing the discharged fine particles.

The present invention is to provide a fluidized bed reactor for synthesizing trichlorosilane, which has the advantage of producing hydrochlorochlorination reaction and direct chlorination reaction of metallurgical grade silicon to produce trichlorosilane.

Furthermore, the present invention provides a fluidized bed reactor for synthesizing trichlorosilane, which has the advantage of being able to remove fine particles generated in the reactor to the outside of the reactor when synthesizing trichlorosilane.

An embodiment of the present invention provides a fluidized bed reactor for synthesizing trichlorosilane, which includes: a reactor having an internal space in which metallurgical grade silicon reacts with feed gas through hydrogen chloride Chemical reaction and direct chlorination reaction to produce trichlorosilane gas; cyclone separator, used to collect fine particles from metallurgical grade silicon granulated and lifted in the internal space of the reactor; bypass line, connected to the reactor, Used to discharge the fine particles to the outside of the reactor; a bypass valve provided in the bypass line; and a separator connected to the bypass valve for discharging the fine particles from the reactor Gas separation and treatment.

The bypass valve can adjust the opening degree of the bypass line.

The ratio of the opening area (OA) of the bypass valve to the inlet area (IA) of the cyclone separator (OA: IA) is one of 1 to 1, 1 to 5 and 1 to 10 (OA: IA=1:1, 1:5 or 1:10). The material of the bypass line and the bypass valve has high corrosion resistance and can be selected from one of Incoloy 800 alloy, Incoloy 800H alloy and Hastelloy alloy.

The separator may include: a cavity connected to the bypass line; a cyclone separator provided in the cavity; and a filter provided in a feed line of the cyclone separator. The separator contains The filter can be selected from one of a vertical filter, a horizontal filter, and a ceramic membrane.

The material of the separator has high corrosion resistance and is selected from one of Incoloy 800 alloy, Incoloy 800H alloy and Hastelloy alloy.

According to an embodiment of the present invention, when trichlorosilane is synthesized, the fine particles that are micronized from metallurgical grade silicon in the internal space of the reactor are discharged to the outside of the reactor, thereby removing the fine particles, so that the flow can be stabilized Fluidized bed reactor. In addition, it is possible to avoid stopping the operation of the fluidized bed reactor, whereby the operation time can be extended, the yield of trichlorosilane gas and the flow characteristics of metallurgical grade silicon can be improved, and the cost can also be reduced. Furthermore, problems that may arise due to the presence of fine particles in the reactor during the subsequent process stages can also be avoided.

10‧‧‧Reactor

20‧‧‧Cyclone

21‧‧‧ Feeding line

30‧‧‧Bypass line

40‧‧‧Bypass valve

50‧‧‧separator

51‧‧‧ Cavity

52‧‧‧Cyclone

53‧‧‧filter

60‧‧‧ heat exchanger

61‧‧‧ First discharge line

62‧‧‧Second discharge line

63‧‧‧Anti-return valve

64‧‧‧Pump

IA‧‧‧ Feeding area

OA‧‧‧Opening area

P‧‧‧fine particles

FIG. 1 is a schematic structural diagram of a fluidized bed reactor for synthesizing trichlorosilane according to an exemplary embodiment of the present invention.

The embodiments of the present invention are listed in detail below, and detailed descriptions are provided in conjunction with the accompanying drawings, so that those with ordinary knowledge in the technical field can implement the present invention accordingly. Those of ordinary skill in the art should understand that several of the embodiments of the present invention can be adjusted in different ways to achieve the present invention without departing from the spirit of the present disclosure.

It should be noted that the drawings are simplified schematic diagrams, which do not limit the present invention. and, In the drawings, symbols are used to describe various components described in the specification.

In addition, for convenience of description, the size and thickness of various components are not drawn in equal proportions in the drawings of the present invention, and the content of the present invention is not limited to the content shown in the drawings.

When it is said in this specification that a component is connected to another component, it includes the case where these components are directly connected to each other, and may also include the case where these components are still indirectly connected with other elements. In addition, in this description room, when there is no other contrary situation specifically described, "including/including any device/component" can be understood as the existence of these devices/components, but the existence of other devices/components is not excluded.

FIG. 1 is a schematic structural diagram of a fluidized bed reactor for synthesizing trichlorosilane according to an exemplary embodiment of the present invention. As shown in FIG. 1, a fluidized bed reactor for synthesizing trichlorosilane (hereinafter referred to as fluidized bed reactor) according to an exemplary embodiment of the present invention includes a reactor 10, a cyclone separator 20, and a bypass Line 30, bypass valve 40, and separator 50.

The reactor 10 has an internal space in which the reaction takes place. Metallurgical-grade silicon and feed gas will generate trichlorosilane gas through the hydrochlorination reaction and direct chlorination reaction in the internal space, and generate micronized fine particles P with time.

For example, metallurgical grade silicon is supplied into the internal space of the reactor 10 (not shown), and feed gas for fluidizing metallurgical grade silicon is supplied into the reactor 10. The feed gas system is supplied upward from the lower part of the reactor 10 to fluidize the metallurgical grade silicon.

When trichlorosilane is synthesized, the fine particles P in the inner space of the reactor 10 will be lifted. A cyclone separator 20 is provided in the inner space of the reactor 10 to collect the lifted fine particles P in the inner space, and part of the fine particles P that have not been collected are discharged to the heat exchanger 60 through the first discharge line 61.

The fine particles P collected through the feed line 21 of the cyclone 20 will be sent back to the internal space of the reactor 10 through the feeder 22 connected to the cyclone 20, so these fine particles P can be reused Silicon is fluidized.

The bypass line 30 is connected to the upper part of the reactor 10 to discharge the fine particles P lifted up in the internal space out of the reactor 10. That is, when trichlorosilane is synthesized, the bypass line 30 and the cyclone 20 can collect the fine particles P in the upper part of the reactor 10 to remove the fine particles P.

A bypass valve 40 is provided in the bypass line 30, whereby when the fine particles P need to be discharged, the opening/closing of the bypass line 30 can be adjusted and the opening/closing operation and the opening degree adjustment operation can be adjusted. Opening degree. Thereby, the fine particles P can be continuously discharged without stopping the operation of the reactor 10.

Therefore, the operation time of the reactor 10 for synthesizing trichlorosilane can be extended, the yield of trichlorosilane can be increased, and the cost can also be reduced.

For example, the bypass line 30 and the bypass valve 40 may be made of Incoloy 800 alloy, Incoloy 800H alloy, or Hastelloy alloy with high corrosion resistance. Therefore, it is possible to effectively prevent the exhaust gas and fine particles from corroding the bypass line 30 and the bypass valve 40.

At the same time, the ratio of the opening area (OA) of the bypass valve 40 to the inlet area (IA) of the cyclone 20 (OA: IA) is 1 to 1, 1 to 5 and 1 to 10. One of them.

That is, the fine particles P may be introduced into the cyclone 20 or be removed to the upper bypass valve 40. Most of the fine particles P introduced into the feed line 21 of the cyclone 20 will be collected and sent back to the reactor 10, but part of the fine particles P will not be collected and lost, so it will pass through the first discharge line 61 And discharged. At the same time, the fine particles P moved to the upper bypass valve 40 can be discharged to the outside of the reactor 10 via the bypass line 30. The separator 50 is connected to the bypass valve 40 to separate and process the fine particles P in the exhaust gas discharged from the reactor 10.

The bypass line 30 and the bypass valve 40 in the internal space of the reactor 10 may be provided separately from the cyclone 20 to adjust the discharge amount of the fine particles P discharged from the reactor 10. That is, the bypass valve 40 can adjust the discharge rate of the fine particles P to be greater than the accumulation rate of the fine particles P in the reactor 10.

As mentioned above, since the bypass line 30, the bypass valve 40 and the separator 50 can remove the fine particles P, the fine particles P will cause the flow characteristics of the metallurgical grade silicon in the internal space of the reactor 10 to be unstable and not reactive Therefore, the operation of the reactor 10 can be extended without stopping the operation. Thereby, the economic loss caused by stopping the operation of the reactor 10 can be avoided.

By adjusting the opening degree to control the discharge rate of the fine particles P, the bypass valve 40 can stabilize the flow characteristics of the metallurgical grade silicon in the internal space of the reactor 10. Therefore, unnecessary loss of productivity can be reduced by controlling the discharge rate of the fine particles P.

For example, the separator 50 may include a cavity 51 connected to the bypass line 30, a cyclone separator 52 provided in the cavity 51, and a filter 53 provided in the feed line of the cyclone separator 52.

Therefore, the fine particles P contained in the exhaust gas and introduced into the separator 50 through the bypass line 30 are filtered by the filter 53 provided in the feed line of the cyclone 52 and collected in the cavity 51 .

For example, the filter 53 may be composed of a vertical filter, a horizontal filter, or a ceramic membrane, depending on the position of the feed line of the cyclone 52.

For example, the separator 50 has high corrosion resistance and is made of Incoloy 800 alloy, Incoloy 800H alloy, or Hastelloy alloy. Therefore, corrosion of the separator 50 by the exhaust gas and the fine particles P can be effectively prevented.

The discharge of the fine particles P formed from metallurgical grade silicon and formed in the internal space of the reactor 10 can be determined by controlling the opening area of the bypass valve 40. Therefore, the fine particles P having no reactivity will not accumulate in the internal space of the reactor 10, or the accumulated fine particles P are within the range where the flow characteristics of metallurgical grade silicon are not suppressed.

According to an exemplary embodiment of the present invention, the fluidized bed reactor further includes a heat exchanger 60 connected to the cyclone 20 and the separator 50 in the internal space of the reactor 10.

Therefore, the cyclone 20 is connected to the heat exchanger 60 via the first discharge line 61. After the fine particles P are collected by the cyclone 20, the high temperature containing part of the fine particles P that are not collected The exhaust gas is exhausted to the heat exchanger 60 through the first exhaust line 61.

The separator 50 is connected to the heat exchanger 60 via the second discharge line 62. After the fine particles P are separated and processed by the separator 50, the high-temperature exhaust gas is exhausted to the heat exchanger 60 through the second exhaust line 62.

The second exhaust line 62 is provided with a backflow prevention valve 63. Therefore, when high-temperature exhaust gas is exhausted to the second exhaust line 62, high-temperature exhaust gas from the first exhaust line 61 and the heat exchanger 60 can be avoided倒流到第二排线62。 The reverse flow to the second discharge line 62.

In addition, the pump 64 is connected to the end of the heat exchanger 60. When the high-temperature exhaust gas passes through the first exhaust line 61, the second exhaust line 62, and the heat exchanger 60, the pump 64 exhausts the quenching gas cooled from the high-temperature exhaust gas.

As described above, since the fine particles P are processed separately in the separator 50, problems that may be caused by the fine particles P in the subsequent process stage structure of the reactor 10 (such as the heat exchanger 60 and the pump 64, etc.) can be avoided .

For example, according to an exemplary embodiment, when trichlorosilane is synthesized in a fluidized bed reactor, the upper part of the internal space of the reactor 10 is bound to have scattered fine particles P. In this case, the amount of fine particles P discharged from the bypass line 30 of the reactor 10 is adjusted by adjusting the opening area of the bypass valve 40. The above description can be verified by the following experiment.

Please refer to the first experimental example, when the metallurgical grade silicon and the feed in the internal space of the reactor 10 When the flow rate of the gas is 0.1 m/s, and the area ratio (OA:IA) of the opening area (OA) of the bypass valve 40 to the feeding area (IA) of the cyclone 20 is 1:1, the fine particles P The discharge rate through the bypass valve 40 was 8.75 g/min.

Please refer to the second experimental example, when the flow rate of the metallurgical grade silicon and the feed gas in the internal space of the reactor 10 is 0.1 m/s, and the opening area of the bypass valve 40 is the area of the feed area of the cyclone separator When the ratio (OA:IA) is 1:5, the discharge rate of the fine particles P through the bypass valve 40 is 1.67 g/min.

Please refer to the third experimental example, when the flow rate of the metallurgical grade silicon and the feed gas in the internal space of the reactor 10 is 0.1 m/s, and the opening area of the bypass valve 40 is the area of the feed area of the cyclone separator When the ratio (OA:IA) is 1:10, the discharge rate of the fine particles P through the bypass valve 40 is 0.3 g/min.

With reference to the first to third experimental examples, it can be understood that at the same flow rate (0.1 m/s), when the area ratio (OA: IA) increases, compared to the feed area (IA), the opening area ( OA) will decrease, and the discharge rate of fine particles P through the bypass valve 40 will decrease.

Please refer to the fourth experimental example, when the flow rate of the metallurgical grade silicon and the feed gas in the internal space of the reactor 10 is 0.15 m/s, and the opening area of the bypass valve 40 is the area of the feed area of the cyclone separator When the ratio (OA:IA) is 1:1, the discharge rate of the fine particles P through the bypass valve 40 is 25 g/min.

Please refer to the fifth experimental example, when the flow rate of the metallurgical grade silicon and the feed gas in the internal space of the reactor 10 is 0.15 m/s, and the opening area of the bypass valve 40 is the area of the feed area of the cyclone separator When the ratio (OA:IA) is 1:5, the discharge rate of the fine particles P through the bypass valve 40 is 8.33 g/min.

Please refer to the sixth experimental example, when the flow rate of the metallurgical grade silicon and the feed gas in the internal space of the reactor 10 is 0.15 m/s, and the opening area of the bypass valve 40 is the area of the feed area of the cyclone separator When the ratio (OA:IA) is 1:1, the discharge rate of the fine particles P through the bypass valve 40 is 1.6 g/min.

With reference to the fourth to sixth experimental examples, it can be understood that at the same flow rate (0.1 m/s), when the area ratio (OA: IA) increases, the opening area is (compared to the feed area (IA)) OA) ratio will decrease, and the discharge rate of fine particles P through the bypass valve 40 will decrease.

In the first to third experimental examples, the flow rate is 0.1 m/s, and in the fourth to sixth experimental examples, the flow rate is 0.15 m/s. From the above, it can be understood that when the flow rate increases, the discharge rate of the fine particles P is significantly different.

Under normal operation of the fluidized bed reactor, the state in which the anti-backflow valve 63 and the bypass valve 40 are simultaneously closed is maintained. The separator 50 maintains the same internal pressure as the reactor 10. That is, when there is no need to discharge the fine particles P, most of the fine particles P collected by the cyclone 20 will be re-circulated in the internal space.

When it is not necessary to discharge the fine particles P, the bypass valve 40 and the anti-backflow valve 63 of the reactor 10 are simultaneously opened, thereby exhausting the gas to form a fluid flowing to the separator 50. Therefore, the fine particles P are discharged to the outside of the reactor 10.

Here, the heat exchanger 60 is operated at a pressure lower than the reactor 10 by about 1 to 2 bar. Therefore, the high-temperature exhaust gas discharged to the separator 50 is supplied to the heat exchanger 60 through the second discharge line 62 and the backflow prevention valve 63. Pump 64 is operated at a pressure less than heat exchanger 60 by about 1 to 2 bar Make. Depending on the driving of the pump 64, the quenching gas cooled in the heat exchanger 60 may be discharged from the heat exchanger 60.

After the fine particles P are completely discharged from the reactor 10 to the separator 50, they are discharged by closing the anti-backflow valve to block the discharged gas. Next, the bypass valve 40 of the reactor 10 is closed to block the exhaust gas and the fine particles P from being discharged.

The above are only exemplary embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

10‧‧‧Reactor

20‧‧‧Cyclone

21‧‧‧ Feeding line

30‧‧‧Bypass line

40‧‧‧Bypass valve

50‧‧‧separator

51‧‧‧ Cavity

52‧‧‧Cyclone

53‧‧‧filter

60‧‧‧ heat exchanger

61‧‧‧ First discharge line

62‧‧‧Second discharge line

63‧‧‧Anti-return valve

64‧‧‧Pump

IA‧‧‧ Feeding area

OA‧‧‧Opening area

P‧‧‧fine particles

Claims (6)

A fluidized bed reactor for synthesizing trichlorosilane (trichlorosilane). The fluidized bed reactor includes: a reactor having an internal space for metallurgical grade silicon to react with feed gas therein , Through a hydrochlorination reaction (hydrochlorination reaction) and direct chlorination reaction (direct chlorination reaction) to produce trichlorosilane gas; a cyclone (cyclone), used to collect the metallurgical grade silicon particles and in the reaction Fine particles whose internal space of the reactor is lifted; a bypass line connected from the outside of the reactor to the reactor for discharging the fine particles to the outside of the reactor; a bypass valve provided on the bypass In the circuit; and a separator, which is provided outside the reactor and connected to the bypass valve, for separating and treating the exhaust gas of the fine particles discharged from the reactor, and wherein the bypass valve The opening/closing and opening degree of the bypass line can be adjusted to control the amount of the exhaust gas discharged from the reactor to the separator. The fluidized bed reactor according to claim 1, wherein the ratio of an opening area (OA) of the bypass valve to an inlet area (IA) of the cyclone separator (OA: IA ) Is one of 1 to 1, 1 to 5 and 1 to 10. The fluidized bed reactor according to claim 1, wherein materials of the bypass line and the bypass valve have high corrosion resistance and are made of one of Incoloy 800 alloy, Incoloy 800H alloy, and Hastelloy alloy. The fluidized bed reactor according to claim 1, wherein the separator includes: a cavity connected to the bypass line; a cyclone separator disposed in the cavity; and a filter disposed in the cyclone separator One feed line. The fluidized bed reactor according to claim 1, wherein the separator includes a filter, and the filter is selected from one of a vertical filter, a horizontal filter, and a ceramic membrane. The fluidized bed reactor according to claim 1, wherein the material of the separator has high corrosion resistance and is made of one of Incoloy 800 alloy, Incoloy 800H alloy, and Hastelloy alloy.

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