JP7605752B2 - Trichlorosilane manufacturing method and trichlorosilane manufacturing apparatus - Google Patents

Description

The present invention relates to a method for producing trichlorosilane and an apparatus for producing trichlorosilane.

Conventionally, ball valves with a ball-shaped valve body are known as valves that open and close flow paths. However, with this ball valve, the valve body rotates while in contact with the seat member, which causes wear on the seat member and makes it impossible to ensure permanent sealing. To solve this problem, for example, Patent Document 1 discloses a non-sliding valve that is configured so that the valve body rotates without contacting the seat member, and then displaces toward the seat member to come into close contact with the seat member, thereby blocking the flow path.

Japanese Patent Application Publication No. 2008-95811

In the technology disclosed in Patent Document 1, by using a non-sliding valve to block the flow path through which the powder flows, the durability of the non-sliding valve can be improved and the replacement frequency of the non-sliding valve can be reduced. However, there has been a demand for further improvement in the durability of the non-sliding valve and further reduction in the replacement frequency. One aspect of the present invention aims to further improve the durability of the non-sliding valve and further reduce the replacement frequency of the non-sliding valve compared to conventional trichlorosilane production methods and production apparatuses.

In order to solve the above problems, a manufacturing method according to one embodiment of the present invention is a method for manufacturing trichlorosilane, in which a flow path through which metal silicon powder flows in the trichlorosilane production system is opened and closed using a non-sliding valve having a valve body that is rotatably mounted without contacting a valve seat, and gas is blown into the space formed between the valve seat and the valve body from an outlet located within the flow path.

In order to solve the above problems, a manufacturing apparatus according to one embodiment of the present invention is a trichlorosilane manufacturing apparatus comprising a pipe through which metal silicon powder flows, and a non-sliding valve provided in the pipe in the trichlorosilane manufacturing system, which opens and closes a flow path of the pipe and has a valve body that is rotatably provided without contacting a valve seat, and an outlet for blowing gas into a space formed between the valve seat and the valve body is disposed in the flow path.

According to one aspect of the present invention, the durability of the non-sliding valve can be further improved and the replacement frequency of the non-sliding valve can be further reduced compared to conventional trichlorosilane manufacturing methods and manufacturing apparatus.

1 is a schematic diagram showing an example of a configuration of a manufacturing apparatus according to a first embodiment of the present invention. 2 is a diagram showing the operation of a non-sliding valve provided in the manufacturing apparatus shown in FIG. 1 when the non-sliding valve is closed. FIG. 2 is a diagram showing the operation of a non-sliding valve provided in the manufacturing apparatus shown in FIG. 1 when the non-sliding valve is opened. FIG. 2 is a diagram showing a structure in the vicinity of a discharge port disposed in a flow path through which metal silicon powder flows in the manufacturing apparatus shown in FIG. 1. FIG. FIG. 5 is a schematic diagram showing an example of the configuration of a manufacturing apparatus according to a second embodiment of the present invention.

[Embodiment 1]
(Configuration of manufacturing apparatus 1)
FIG. 1 is a schematic diagram showing an example of the configuration of a manufacturing apparatus 1 according to the first embodiment of the present invention. In this specification, the manufacturing apparatus 1 is not particularly limited as long as it is a trichlorosilane manufacturing apparatus that uses metal silicon powder to manufacture trichlorosilane. For example, the manufacturing apparatus 1 may be a fluidized bed type reactor. By using the fluidized bed type reactor, it is possible to continuously supply metal silicon powder and hydrogen chloride to continuously synthesize trichlorosilane. Note that trichlorosilane is also referred to as _SiHCl3 or TCS.

In the reaction between metal silicon powder and hydrogen chloride, a large amount of metal silicon is used, and the metal silicon powder is likely to get caught in a valve installed in the flow path through which the metal silicon powder flows, causing damage to the valve seat. Therefore, a non-sliding valve is installed in the flow path through which the metal silicon powder flows, and gas is sprayed into the space formed between the valve seat and the valve body. As a result, the effect of one aspect of the present invention, which is to suppress damage to the valve seat, is particularly pronounced in the reaction between metal silicon powder and hydrogen chloride.

In addition, unless otherwise specified in this specification, "A to B" representing a numerical range means "A or more (including A and larger than A) and B or less (including B and smaller than B)." In addition, in the following, an example will be described using the device in Figure 1 that reacts metal silicon powder with hydrogen chloride to produce trichlorosilane, but other devices that produce trichlorosilane using metal silicon powder may also be used.

In this specification, "metal silicon powder" refers to a solid substance containing silicon element in a metallic state, such as metallurgical metal silicon, ferrosilicone, or polysilicon, and any known substance may be used without any restrictions. Furthermore, such metal silicon powder may contain impurities such as iron compounds, and there are no particular restrictions on the components and content thereof. Such metal silicon powder is usually used in the form of a fine powder with an average particle size of about 150 to 350 μm.

As shown in Figure 1, the manufacturing apparatus 1 includes compressors 2 and 11, a reaction vessel 3, coolers 4, 7 and 9, a filter 5, a storage tank 6, a heat medium drum 8, a condenser 10, a distillation column 13 and non-sliding valves b1 to b4. These components of the manufacturing apparatus 1 are connected to each other by piping.

The manufacturing apparatus 1 also includes a pipe through which metal silicon powder flows, and produces trichlorosilane. The pipe through which metal silicon powder flows is the pipe of the flow path through which metal silicon powder flows in the trichlorosilane production system. The pipe of the flow path through which metal silicon powder flows is, for example, the pipe of the inlet flow path f1, the outlet flow path f2, the exhaust flow path f31, and the exhaust flow path f32 described below. The trichlorosilane production system refers to the entire manufacturing apparatus that produces trichlorosilane, and for example refers to at least one of the entire manufacturing apparatus 1 and the entire manufacturing apparatus 1A described below.

In the method for producing trichlorosilane using the production apparatus 1, the flow paths through which the metal silicon powder flows in the trichlorosilane production system are opened and closed using non-sliding valves b1 to b4. The flow paths through which the metal silicon powder flows in the trichlorosilane production system are, for example, the inlet flow path f1, outlet flow path f2, exhaust flow path f31, and exhaust flow path f32 described below.

The compressor 2 is provided in a pipe through which hydrogen chloride flows, compresses the hydrogen chloride flowing inside the pipe, and supplies the hydrogen chloride to the reaction vessel 3. The reaction vessel 3 contains metal silicon powder and hydrogen chloride supplied from the outside, and reacts the metal silicon powder with the hydrogen chloride to produce trichlorosilane. Inside the reaction vessel 3, reactions mainly occur as shown in the following formulas (1) and (2).
Metal silicon powder (Si) + 3HCl → SiHCl ₃ + H ₂ ... (1)
Metal silicon powder (Si) + 4HCl → _SiCl4 + 2H2 _... (2)

There is no particular limitation on the shape of the reaction vessel 3 (in other words, the shape of the sidewall of the reaction vessel 3). For example, the sidewall of the reaction vessel 3 surrounding the fluidized bed (not shown) may have a shape (not shown) in which the cross-sectional area of a cut surface perpendicular to the height direction of the reaction vessel 3 is constant, or may have a tapered shape (not shown) that increases toward the top.

A non-sliding valve b1 is provided in the piping of the inlet flow path f1 that introduces metal silicon powder from outside the reaction vessel 3 to the reaction vessel 3. As shown in FIG. 2, the non-sliding valve b1 includes stems 31, 32, a valve body 33, valve seats 35, 36, and a main body 40. The non-sliding valve b1 opens and closes the inlet flow path f1. The inlet flow path f1 is part of the flow path through which metal silicon powder flows in the trichlorosilane production system.

Because the particle size of the metal silicon powder is small, even if the sliding part of a conventional valve is made as small as possible, the metal silicon powder will get into the valve when it slides, and the valve seat will be damaged by the metal silicon powder. For this reason, it is preferable to use a non-sliding valve b1 that does not have a sliding part.

In particular, in the reaction of producing trichlorosilane by reacting metal silicon powder with hydrogen chloride, a large amount of metal silicon is used, so the valve provided in the inlet flow path f1 is opened and closed frequently. Therefore, by providing the non-sliding valve b1 in the inlet flow path f1, the effect of suppressing damage to the valve seats 35, 36 is particularly remarkable in the reaction of producing trichlorosilane by reacting metal silicon powder with hydrogen chloride. The operation of the non-sliding valve b1 will be described in detail later.

A heat medium pipe 15 for circulating a heat medium is provided inside the reaction vessel 3. The heat medium pipe 15 connects the cooler 7 and the heat medium drum 8. The cooler 7 lowers the temperature of the heat medium circulating inside the heat medium pipe 15, and the heat medium drum 8 stores the heat medium.

A non-sliding valve b2 is provided in the piping of the outlet flow path f2 through which the metal silicon powder extracted from the bottom of the reaction vessel 3 flows. The non-sliding valve b2 opens and closes the outlet flow path f2. The outlet flow path f2 is located between the reaction vessel 3 and the storage tank 6 that stores the metal silicon powder extracted from the bottom of the reaction vessel 3. The outlet flow path f2 is part of the flow path through which the metal silicon powder flows in the trichlorosilane production system.

In particular, in the reaction of producing trichlorosilane by reacting metal silicon powder with hydrogen chloride, a large amount of metal silicon is used, and therefore a large amount of metal silicon powder is extracted from the bottom of the reaction vessel 3. Therefore, by providing a non-sliding valve b2 in the outlet flow path f2, the effect of suppressing damage to the valve seat is particularly pronounced in the reaction of producing trichlorosilane by reacting metal silicon powder with hydrogen chloride.

The discharge flow path f3, through which the metal silicon powder discharged from the top of the reaction vessel 3 flows, is a flow path from the reaction vessel 3 to the storage tank 6. A non-sliding valve b3 is provided in the piping of the discharge flow path f31 of the discharge flow path f3. The non-sliding valve b3 opens and closes the discharge flow path f31, and is located between the cooler 4 and the filter 5. The discharge flow path f31 is located between the reaction vessel 3 and the filter 5 that removes the metal silicon powder. The discharge flow path f31 is part of the flow path through which the metal silicon powder flows in the trichlorosilane production system. The non-sliding valve b3 may be located between the reaction vessel 3 and the cooler 4.

Of the discharge flow paths f3, discharge flow path f32 carries the metal silicon powder removed by the filter 5. A non-sliding valve b4 is provided in the piping of the discharge flow path f32. The non-sliding valve b4 opens and closes the discharge flow path f32. The discharge flow path f32 is located between the filter 5 and the storage tank 6. The discharge flow path f32 is part of the flow path through which the metal silicon powder flows in the trichlorosilane production system.

Hydrogen, trichlorosilane, tetrachlorosilane, etc. generated in the reaction vessel 3 flow through the discharge flow path f31. A cooler 4 is provided in the piping of the discharge flow path f31. The cooler 4 cools the metal silicon powder, hydrogen, trichlorosilane, tetrachlorosilane, etc. flowing through the discharge flow path f31. Tetrachlorosilane is also referred to as _SiCl4 or STC.

The filter 5 removes the metal silicon powder from the metal silicon powder, hydrogen, trichlorosilane, tetrachlorosilane, etc. cooled by the cooler 4. The filter 5 discharges the removed metal silicon powder into the storage tank 6 and supplies the hydrogen, trichlorosilane, tetrachlorosilane, etc. to the cooler 9. The cooler 9 cools the hydrogen, trichlorosilane, tetrachlorosilane, etc. with cooling water and supplies the cooled hydrogen, trichlorosilane, tetrachlorosilane, etc. to the condenser 10.

The condenser 10 separates hydrogen, trichlorosilane, tetrachlorosilane, etc. into gas and liquid, supplies hydrogen to the compressor 11, and supplies trichlorosilane, tetrachlorosilane, etc. to the distillation column 13. The distillation column 13 recovers trichlorosilane and tetrachlorosilane by distillation.

The compressor 11 is provided in a pipe through which hydrogen flows, and compresses the hydrogen flowing inside the pipe. The compressor 11 supplies compressed hydrogen to a downstream component. A pipe P2 branches off from a pipe P1 connected between the compressor 11 and the downstream component, and is connected to the nozzles 54 of each of the non-sliding valves b1 to b4. The nozzles 54 will be described later. Hydrogen flows inside the pipe P2. A valve may be provided in the pipe P2.

(Non-sliding valve operation)
Fig. 2 is a diagram showing the operation of the non-sliding valve b1 when the non-sliding valve b1 provided in the manufacturing apparatus 1 shown in Fig. 1 is closed. Fig. 3 is a diagram showing the operation of the non-sliding valve b1 when the non-sliding valve b1 provided in the manufacturing apparatus 1 shown in Fig. 1 is opened.

The pipe 34 is an inlet flow path f1 pipe provided with a non-sliding valve b1. The diagram indicated by 101 in FIG. 2 shows the state in which the non-sliding valve b1 is fully open. An opening 37 is formed in the valve body 33. The metal silicon powder flowing inside the pipe 34 passes through the space surrounded by the opening 37. The direction in which the metal silicon powder flows is from the inlet 38 to the outlet 39 of the non-sliding valve b1.

A stem 31 is attached to the upper end of the valve body 33, and a stem 32 is attached to the lower end of the valve body 33. A valve seat 35 is provided at the boundary between the upper recess 41 formed in the main body 40 and the inlet 38, and a valve seat 36 is provided at the boundary between the lower recess 42 formed in the main body 40 and the inlet 38. The valve seats 35, 36 are for maintaining the airtightness of the non-sliding valve b1. The material of the valve seats 35, 36 may be, for example, carbon, Teflon (registered trademark), other resin products, or metal.

As shown by 101 in Figure 2, when the stem 32 is rotated clockwise as viewed from below the non-sliding valve b1, the valve body 33 rotates in the closing direction. When the valve body 33 rotates, it does so without coming into contact with the valve seats 35, 36. When the stem 32 is rotated 90° clockwise, the valve body 33 is in a closed state as shown by 102 in Figure 2. However, the non-sliding valve b1 is not in a completely closed state. Simply rotating the stem 32 90° clockwise does not cause the valve body 33 to come into contact with the valve seats 35, 36.

After the stem 32 has been rotated 90° clockwise, as shown in 103 in Fig. 2, when the stem 31 is rotated clockwise as viewed from above the non-sliding valve b1, the valve body 33 tilts with the stem 31 as the fulcrum. Then, as shown in 104 in Fig. 2, the valve body 33 comes into contact with the valve seats 35, 36. When the stem 31 has finished rotating clockwise, the valve body 33 is pressed against the valve seats 35, 36, and the non-sliding valve b1 is completely closed. In other words, the flow of metal silicon powder inside the pipe 34 is stopped.

Also, the diagram indicated by 201 in Figure 3 shows the state in which the non-sliding valve b1 is completely closed. As indicated by 202 in Figure 3, when viewed from above the non-sliding valve b1, rotating the stem 31 counterclockwise causes the valve body 33 to move in a direction away from the valve seats 35, 36, with the stem 31 as a fulcrum. As indicated by 203 in Figure 3, when the stem 31 has finished rotating counterclockwise, the valve body 33 has completely separated from the valve seats 35, 36.

After the stem 31 has been rotated counterclockwise, as shown by 203 in Figure 3, when the stem 32 is rotated counterclockwise as viewed from below the non-sliding valve b1, the valve body 33 rotates in the opening direction. When the valve body 33 rotates, it does not come into contact with the valve seats 35, 36. When the stem 32 is rotated counterclockwise by 90°, the non-sliding valve b1 is fully open as shown by 204 in Figure 3.

Therefore, the non-sliding valve b1 has a valve body 33 that is rotatably mounted in a non-contact state with respect to the valve seats 35, 36. The non-sliding valve b1 is also mounted in the pipe 34 and opens and closes the flow path of the pipe 34.

The non-sliding valve b1 may also have a structure in which the valve body 33 and the valve seats 35, 36 are in metal contact. Metal touch means that two metal objects come into contact with each other. In other words, the valve body 33 and the valve seats 35, 36 are made of metal, and when the stem 31 is rotated clockwise, the valve body 33 and the valve seats 35, 36 come into contact with each other. As a result, when the non-sliding valve b1 is closed, the valve body 33 and the valve seats 35, 36 come into metal contact. Therefore, since the heat resistance temperature of the non-sliding valve b1 exceeds 200°C, the non-sliding valve b1 can be used at temperatures exceeding 200°C.

The non-sliding valves b2 to b4 and the non-sliding valves b5 to b8 described below have the same structure as the non-sliding valve b1. The structure of the non-sliding valves b1 to b8 is not limited to the structure described here, and is not particularly limited as long as the valve body and the valve seat do not slide.

(Structure of outlet)
Fig. 4 is a diagram showing the structure of the vicinity of a discharge port 51 arranged in a flow path through which metal silicon powder flows in the manufacturing apparatus 1 shown in Fig. 1. Here, for example, the structure of the discharge port 51 arranged inside the non-sliding valve b1 will be described. As shown in Fig. 4, a nozzle 54 is attached to the outside of the non-sliding valve b1. Specifically, the nozzle 54 is attached to the side of the main body 40 opposite to the side on which the valve seat 35 is provided. In addition, the discharge port 51 is arranged inside the non-sliding valve b1.

Between the discharge port 51 and the nozzle 54, paths 52 and 53 through which gas flows are formed. The path 52 is formed in the valve seat 35, and the path 53 is formed in the main body 40. The aforementioned pipe P2 is connected to the nozzle 54, so that hydrogen flows through the nozzle 54. The hydrogen flows through the paths 52 and 53 and is discharged from the discharge port 51.

In this way, the nozzle 54 is for circulating the gas to the discharge port 51 and is provided in the manufacturing apparatus 1. According to the above configuration, the nozzle 54 having an appropriate nozzle diameter can be provided outside the non-sliding valve b1 so that the desired linear velocity of the gas discharged from the discharge port 51 can be obtained.

In addition, an outlet 51 for blowing gas into the space SP formed between the valve seat 35 and the valve body 33 is disposed in the flow path through which the metal silicon powder flows. In other words, gas is blown into the space SP from the outlet 51 disposed in the flow path through which the metal silicon powder flows.

According to the above configuration, the metal silicon powder adhering to the valve seat 35 and valve body 33 can be blown away by gas. This improves the sealing performance between the valve seat 35 and valve body 33 when the flow path is blocked by the non-sliding valve b1. This further improves the durability of the non-sliding valve b1 and further reduces the frequency of replacement of the non-sliding valve b1 compared to conventional manufacturing methods. By blowing gas into the space SP, the gas can be blown onto both the valve seat 35 and the valve body 33.

In addition, the discharge port 51 may also be formed in the valve seat 36, and a nozzle 54 may also be attached to the side of the main body 40 opposite to the side where the valve seat 36 is provided. In other words, gas may also be blown into the space formed between the valve seat 36 and the valve body 33. In addition, two discharge ports 51 may be arranged symmetrically with respect to the valve body 33, or three or more discharge ports 51 may be arranged at equal intervals around the valve body 33. In this case, a nozzle 54 is attached to the side of the main body 40 opposite to the side where each discharge port 51 is arranged.

The gas is blown into the space SP immediately before the stem 31 is rotated clockwise in the diagram indicated by 103 in Figure 2. In other words, when the non-sliding valve b1 is closed, the gas is blown into the space SP immediately before the valve body 33 comes into contact with the valve seats 35, 36.

Furthermore, because hydrogen flows through the nozzle 54, hydrogen is used as the gas to be sprayed into the space SP. With the above configuration, it is possible to easily realize a structure in which hydrogen, which is a gas that circulates in the trichlorosilane production system, is used to spray gas into the space SP formed between the valve seat 35 and the valve body 33.

Hydrogen generated in the reaction vessel 3 flows through the pipe P2, and the hydrogen flowing through the pipe P2 is discharged from the discharge port 51, so that the hydrogen sprayed into the space SP becomes hydrogen circulating in the manufacturing apparatus 1. In this way, hydrogen circulating in the trichlorosilane manufacturing system is used as the gas sprayed into the space SP.

According to the above configuration, by using hydrogen circulating in the trichlorosilane production system, it is not necessary to mix gases not used in the trichlorosilane production system into the flow path through which the metal silicon powder flows. This makes it possible to avoid the burden of processing to remove the gas in a subsequent process in the trichlorosilane production system. In addition, since the hydrogen circulating in the trichlorosilane production system can be reused as hydrogen to be sprayed into the space SP, the cost of producing trichlorosilane can be reduced.

The amount of gas sprayed into the space SP is, for example, 50 to 200 L per nozzle 54. When gas is sprayed into the space SP, the number of times the gas is sprayed is, for example, one time. In other words, by closing the non-sliding valve b1 while gas is being sprayed into the space SP within a specified gas spraying period, the number of times the gas is sprayed is set to one time.

It is also preferable to blow the gas into the space SP at a linear velocity of 30 m/s to 300 m/s for a period of 5 seconds to 50 seconds. Here, the range in which the linear velocity of the gas is 30 m/s to 300 m/s and the blowing time of the gas is 5 seconds to 50 seconds is referred to as range R1.

As shown in Table 1 below, when pressure was applied to the outlet 39 of the non-sliding valve b1 after the non-sliding valve b1 was closed, the pressure changed slightly when it was below range R1, and did not change when it was within range R1 or above range R1. The change in pressure indicates that metal silicon powder has adhered to the valve seat 35 or valve body 33 and that gas leakage has occurred. The pressure was observed by visually observing the pressure gauge that measures the pressure.

In addition, in the gas spraying operation, the amount of gas used per nozzle 54 is 20 L or less when it is below range R1, 50 to 200 L when it is within range R1, and 250 L or more when it is above range R1. Therefore, when it is within range R1, the metal silicon powder adhering to the valve seat 35 and valve body 33 can be sufficiently blown away by the gas, and the amount of gas used can be reduced, thereby reducing costs. Also, examples of why it is preferable to be within range R1 are shown in Examples 1 and 2 described below.

The non-sliding valves b2 to b4 and the non-sliding valves b5 to b8 described below have the same structure as the non-sliding valve b1. Therefore, with regard to the structure near the discharge port 51 shown in Figure 4, the structures of the non-sliding valves b2 to b4 and the non-sliding valves b5 to b8 are the same as the structure of the non-sliding valve b1.

[Embodiment 2]
A second embodiment of the present invention will be described below. For convenience of explanation, the same reference numerals are used for members having the same functions as those described in the first embodiment, and the explanations thereof will not be repeated. Fig. 5 is a schematic diagram showing an example of the configuration of a manufacturing apparatus 1A according to the second embodiment of the present invention.

5, the manufacturing apparatus 1A includes a heat exchanger 21, a heater 22, a second reaction vessel 23, a second filter 24, a second storage tank 25, a cooler 26, a condenser 27, a compressor 28, a distillation column 29, and non-sliding valves b5 to b8. These components of the manufacturing apparatus 1A are connected to each other by piping. In this embodiment, the flow paths through which the metal silicon powder flows in the trichlorosilane manufacturing system are the second inlet flow path f5, the second outlet flow path f61, the second outlet flow path f62, and the second outlet flow path f8.

Hydrogen and tetrachlorosilane are supplied to the heat exchanger 21. The hydrogen is supplied from the compressor 28, and the tetrachlorosilane is supplied from the distillation column 29. The tetrachlorosilane may be, for example, generated as a side reaction by the reaction vessel 3 described above. The heat exchanger 21 exchanges heat between the metal silicon powder, hydrogen, and trichlorosilane that have passed through the second reaction vessel 23 and the hydrogen and tetrachlorosilane. The heat exchanger 21 supplies the hydrogen and tetrachlorosilane to the heater 22.

The heater 22 heats tetrachlorosilane and hydrogen and supplies the tetrachlorosilane and hydrogen to the second reaction vessel 23. The second reaction vessel 23 contains tetrachlorosilane, hydrogen, and metal silicon powder supplied from the outside, and reacts the tetrachlorosilane, hydrogen, and metal silicon powder to generate trichlorosilane. Inside the second reaction vessel 23, the reaction shown in the following formula (3) mainly occurs. The second reaction vessel 23 supplies the metal silicon powder, hydrogen, trichlorosilane, and unreacted tetrachlorosilane to the second filter 24 via the heat exchanger 21.
Metal silicon powder (Si) + _3SiCl4 + _2H2 → 4SiHCl3 _... (3)

The second filter 24 removes the metal silicon powder from the metal silicon powder, hydrogen, trichlorosilane, and unreacted tetrachlorosilane supplied from the second reaction vessel 23 via the heat exchanger 21. The second filter 24 supplies the removed metal silicon powder to the second storage tank 25.

A non-sliding valve b5 is provided in the piping of the second inlet flow path f5, which introduces the metal silicon powder from outside the second reaction vessel 23 to the second reaction vessel 23. The non-sliding valve b5 opens and closes the second inlet flow path f5. The second inlet flow path f5 is part of the flow path through which the metal silicon powder flows in the trichlorosilane production system.

The second discharge flow path f6, through which the metal silicon powder discharged from the second reaction vessel 23 flows, is a flow path from the second reaction vessel 23 to the second storage tank 25. A non-sliding valve b6 is provided in the piping of the second discharge flow path f61 of the second discharge flow path f6. The non-sliding valve b6 opens and closes the second discharge flow path f61, and is located between the heat exchanger 21 and the second filter 24.

The second exhaust flow path f61 is located between the second reaction vessel 23 and the second filter 24 that removes the metal silicon powder. The second exhaust flow path f61 is part of the flow path through which the metal silicon powder flows in the trichlorosilane production system. The non-sliding valve b6 may be located between the second reaction vessel 23 and the heat exchanger 21.

The metal silicon powder removed by the second filter 24 flows through the second discharge flow path f62 of the second discharge flow path f6. A non-sliding valve b7 is provided in the piping of the second discharge flow path f62. The non-sliding valve b7 opens and closes the second discharge flow path f62. The second discharge flow path f62 is located between the second filter 24 and the second storage tank 25. The second discharge flow path f62 is part of the flow path through which the metal silicon powder flows in the trichlorosilane production system.

A non-sliding valve b8 is provided in the piping of the second outlet flow path f8 through which the metal silicon powder extracted from the bottom of the second reaction vessel 23 flows. The non-sliding valve b8 opens and closes the second outlet flow path f8. The second outlet flow path f8 is located between the second reaction vessel 23 and the second storage tank 25 that contains the metal silicon powder extracted from the bottom of the second reaction vessel 23. The second outlet flow path f8 is part of the flow path through which the metal silicon powder flows in the trichlorosilane production system.

In addition, the second filter 24 supplies hydrogen, trichlorosilane, and unreacted tetrachlorosilane to the cooler 26. The cooler 26 cools the hydrogen, trichlorosilane, and unreacted tetrachlorosilane with cooling water, and supplies the cooled hydrogen, trichlorosilane, and unreacted tetrachlorosilane to the condenser 27.

The condenser 27 separates hydrogen, trichlorosilane, and unreacted tetrachlorosilane into gas and liquid, supplies hydrogen to the compressor 28, and supplies trichlorosilane and tetrachlorosilane to the distillation column 29. The distillation column 29 recovers trichlorosilane and tetrachlorosilane by distillation. The distillation column 29 supplies the recovered tetrachlorosilane to the heat exchanger 21.

The compressor 28 is provided in the piping through which hydrogen flows, and compresses the hydrogen flowing inside the piping. The compressor 28 supplies compressed hydrogen to the heat exchanger 21. Pipe P4, which branches off from pipe P3 connected between the compressor 28 and the heat exchanger 21, is connected to the nozzles 54 of each of the non-sliding valves b5 to b8. Hydrogen flows inside pipe P4. Hydrogen generated in the second reaction vessel 23 flows through pipe P4, and the hydrogen flowing through pipe P4 is discharged from the discharge port 51, so that the hydrogen sprayed into the space becomes hydrogen circulating in the production apparatus 1A.

〔summary〕
A manufacturing method according to one aspect of the present invention is a method for manufacturing trichlorosilane, in which a flow path through which metal silicon powder flows in a trichlorosilane production system is opened and closed using a non-sliding valve having a valve body that is rotatably mounted without contacting a valve seat, and gas is blown from an outlet located in the flow path into a space formed between the valve seat and the valve body.

According to the above configuration, metal silicon powder adhering to the valve seat and valve body can be blown away by gas. This improves the sealing performance between the valve seat and valve body when the flow path is blocked by the non-sliding valve. This further improves the durability of the non-sliding valve and further reduces the frequency of replacement of the non-sliding valve compared to conventional manufacturing methods.

In the manufacturing method, hydrogen may be used as the gas to be sprayed into the space. According to the configuration, a structure in which hydrogen, which is a gas circulating in a trichlorosilane manufacturing system, is used to spray gas into the space formed between the valve seat and the valve body can be easily realized.

In the manufacturing method, hydrogen circulating in the trichlorosilane manufacturing system may be used as the gas to be sprayed into the space. According to the configuration, by using hydrogen circulating in the trichlorosilane manufacturing system, it is not necessary to mix gas not used in the trichlorosilane manufacturing system into the flow path through which the metal silicon powder flows. This makes it possible to avoid the burden of a process for removing the gas in a subsequent process of the trichlorosilane manufacturing system. In addition, since the hydrogen circulating in the trichlorosilane manufacturing system can be reused as hydrogen to be sprayed into the space, the cost of manufacturing trichlorosilane can be reduced.

In the manufacturing method, the gas may be sprayed into the space at a linear velocity of 30 m/s to 300 m/s for a period of 5 to 50 seconds. According to the configuration, the metal silicon powder adhering to the valve seat and the valve body can be sufficiently blown away by the gas, and the amount of gas used can be reduced, thereby reducing costs.

A manufacturing apparatus according to one embodiment of the present invention is a trichlorosilane manufacturing apparatus comprising a pipe through which metal silicon powder flows, and a non-sliding valve provided in the pipe in the trichlorosilane manufacturing system, which opens and closes a flow path of the pipe and has a valve body that is rotatably provided without contacting a valve seat, and an outlet for blowing gas into a space formed between the valve seat and the valve body is disposed in the flow path.

The manufacturing apparatus may further include a nozzle attached to the outside of the non-sliding valve for circulating gas to the discharge port. According to the above configuration, a nozzle having an appropriate nozzle diameter can be provided on the outside of the non-sliding valve so that the desired linear velocity of the gas discharged from the discharge port can be obtained.

The present invention is not limited to the above-described embodiments, but various modifications are possible within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

The present invention will be described in more detail below with reference to Example 1, but the present invention is not limited to Example 1. For the structure of the non-sliding valve, refer to Figures 2 and 4. A non-sliding valve with a nozzle attached was installed on the line through which metal silicon powder was fed into the reactor. The line through which the metal silicon powder passed was a pipe with an inner diameter of 100 mm, and an opening 37 with an inner diameter of 100 mm was formed in the valve body 33 in the non-sliding valve.

The structure of the non-sliding valve is such that by rotating the valve body 33, the flow path through which the metal silicon powder and gas passing through the line is blocked. When the non-sliding valve is completely closed, the valve body 33 comes into contact with the valve seat 35. Before the non-sliding valve is completely closed, one gas line is provided that includes a nozzle 54 for spraying gas into the space SP formed between the valve seat 35 and the valve body 33. The gas line is connected to a hydrogen supply line.

When the non-sliding valve is completely closed, an orifice is provided at the boundary between the nozzle 54 and the main body 40 of the non-sliding valve, and the linear velocity of hydrogen at the discharge port 51 is set to 60 m/sec. By setting the diameter of the orifice to 2-5 mm, the linear velocity of hydrogen was set to 80 m/sec, and the frequency of replacement of the non-sliding valve was dramatically reduced. In this way, by providing a function to blow gas into the space SP formed between the valve seat 35 and the valve body 33, it has become possible to operate the non-sliding valve year-round without replacing it.

The method of operating the non-sliding valve is described below. First, the non-sliding valve is closed. After the non-sliding valve is closed, metal silicon powder is poured into the inlet 38 of the non-sliding valve. After the metal silicon powder is poured, the non-sliding valve is opened and the metal silicon powder is discharged from the outlet 39 of the non-sliding valve. Hydrogen is sprayed from the nozzle 54 onto the valve body 33 at a linear velocity of 60 m/sec for 10 seconds. The operation described here is repeated three times.

With the non-slide valve closed, hydrogen was applied to the outlet 39 of the non-slide valve to check the amount of hydrogen leakage. A stainless steel valve body 33 and a stainless steel or Viton (registered trademark) valve seat 35 were used, and the results are shown in Table 2.

In Table 2, "0.85 MPa" indicates that the hydrogen pressure at the outlet 39 of the non-sliding valve is 0.85 MPa, and "0.15 MPa" indicates that the hydrogen pressure at the outlet 39 of the non-sliding valve is 0.15 MPa. As shown in Table 2, when hydrogen was sprayed on both the stainless steel valve seat 35 and the Viton valve seat 35, the amount of hydrogen leakage was drastically reduced. In particular, when the Viton valve seat 35 was used, no hydrogen leakage occurred.

The present invention will be described in more detail below with reference to Example 2, but the present invention is not limited to Example 2. In Example 2, two gas lines including nozzles 54 for spraying gas into the space SP formed between the valve seat 35 and the valve body 33 before the non-sliding valve is completely closed are provided. The nozzles 54 of the two gas lines are arranged symmetrically with respect to the valve body 33. A test was conducted similarly to Example 1, except that two gas lines were provided and the linear velocity of the hydrogen was changed, and the results are shown in Table 3.

In Table 3, "0.85 MPa" indicates that the hydrogen pressure at the outlet 39 of the non-sliding valve is 0.85 MPa, and "0.15 MPa" indicates that the hydrogen pressure at the outlet 39 of the non-sliding valve is 0.15 MPa. As shown in Table 3, when the linear velocity of hydrogen was 15 m/sec, hydrogen leakage occurred, but when the linear velocity of hydrogen was 30 m/sec, no hydrogen leakage occurred.

The present invention can be used for the production of trichlorosilane.

1, 1A Manufacturing device 33 Valve body 35, 36 Valve seat 51 Discharge port 54 Nozzle b1 to b8 Non-sliding valve SP Space formed between valve seat and valve body

Claims (3)

A method for producing trichlorosilane, comprising the steps of:
In the trichlorosilane production system, a flow path through which the metal silicon powder flows is opened and closed by using a non-sliding valve having a valve body that is rotatably provided in a non-contact state with respect to a valve seat made of resin ,
a discharge port disposed within the flow path, into a space formed between the valve seat and the valve body , and the hydrogen is produced when the metal silicon powder and hydrogen chloride are reacted to produce the trichlorosilane, and the hydrogen is circulated in a production system for the trichlorosilane . 2. The method according to claim 1 , wherein the hydrogen is sprayed into the space at a linear velocity of 30 m/sec to 300 m/sec for a period of 5 seconds to 50 seconds. An apparatus for producing trichlorosilane, comprising:
A pipe through which metal silicon powder flows;
a non-sliding valve provided in the piping in the trichlorosilane production system, for opening and closing a flow path of the piping, and having a valve body rotatably provided in a non-contact state with respect to a valve seat made of resin ;
a discharge port is disposed in the flow path for spraying hydrogen, which is obtained when the metal silicon powder and hydrogen chloride are reacted to produce the trichlorosilane and which circulates in a production system for the trichlorosilane, into a space formed between the valve seat and the valve body.

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