JP5206479B2 - Polycrystalline silicon production equipment - Google Patents

Description

  The present invention relates to a polycrystalline silicon production apparatus for producing polycrystalline silicon rods by depositing polycrystalline silicon on the surface of a silicon core rod heated in a reaction furnace, and in particular, a pipe penetration portion in a bottom plate portion of the reaction furnace. Relates to the cooling structure.

  As this type of polycrystalline silicon manufacturing apparatus, a manufacturing apparatus based on the Siemens method is known. In this polycrystalline silicon manufacturing apparatus, a large number of silicon core rods serving as seed rods are disposed and heated in the reaction furnace, and a raw material gas containing chlorosilane gas and hydrogen gas is supplied to the reaction furnace, It is brought into contact with a heated silicon core rod, and polycrystalline silicon generated by thermal decomposition of the source gas and hydrogen reduction is deposited on the surface thereof.

  In such a polycrystalline silicon manufacturing apparatus, a silicon core rod serving as a seed rod is fixed in an upright state to an electrode disposed on a bottom plate portion of a reaction furnace, and the upper end portions thereof are paired by a short connecting member. By being connected one by one, it is fixed so as to form a square shape. A plurality of source gas jets are provided in the bottom plate portion of the reactor, and are arranged so as to be distributed among a plurality of standing silicon core rods. Then, the silicon core rod is energized from the electrode, the silicon core rod generates heat by its resistance, and the raw material gas ejected from below is brought into contact with the surface of the silicon core rod to deposit polycrystalline silicon. The silicon rod is obtained by growing it around. A plurality of exhaust gas exhaust pipes for exhausting the exhaust gas after the reaction from the reaction furnace are also provided at appropriate intervals on the bottom plate portion of the reaction furnace (see Patent Documents 1 to 3).

In the production of polycrystalline silicon by the Siemens method, since the reaction is generally performed at a high temperature of about 1000 ° C., the reactor itself and its internal atmosphere are also in a high temperature state, so cooling is performed using a jacket method or the like. Often, it is maintained below a certain temperature. For this reason, the walls and bottom plate of the reactor have a double structure so that cooling water can be circulated, and the source gas supply pipe and the exhaust gas discharge pipe penetrate through the double structure bottom plate and react. It arrange | positions so that an upper end may face the inner bottom part of a furnace. These raw material supply pipes and exhaust gas discharge pipes are also formed in a double tubular shape, and cooling water is circulated between the double pipes, but the cooling water is sufficiently distributed to the upper end facing the reactor. It is necessary to make it.
In the case where the cooling water is circulated to the upper end portion of the pipe along the vertical direction, for example, in Patent Document 4, a thin tube is provided at the upper end portion of the pipe, the air vent valve connected to the thin tube is opened, and the upper end of the pipe is opened. The air accumulated in the section is allowed to flow out from the narrow tube.

JP 2006-206387 A Japanese Patent No. 2001-278611 Japanese Patent No. 2867306 Japanese Utility Model Publication No. 52-140121

  However, during operation, the inside of the reaction furnace is in a high temperature state of, for example, 1000 ° C., and a plurality of electrodes are arranged on the inner bottom of the reaction furnace, together with the ejection nozzle and the exhaust gas discharge port for supplying the raw material gas, Each electrode is provided with a polycrystalline silicon rod along the vertical direction. Therefore, it is impossible to provide a narrow pipe for venting air at the upper end of the pipe that penetrates the bottom plate of the reactor because it is a pipe in a limited space under the high temperature environment. is there.

  The present invention has been made in view of such circumstances, and reliably eliminates air accumulation in the double pipes of the source gas supply pipe and the exhaust gas discharge pipe, and the upper ends of these pipes exposed in the reaction furnace. It is an object of the present invention to provide a polycrystalline silicon manufacturing apparatus capable of effectively cooling a part.

  The polycrystalline silicon manufacturing apparatus of the present invention heats a plurality of silicon core rods in a reaction furnace, and deposits polycrystalline silicon around the silicon core rods by reaction of a source gas supplied from a source gas supply pipe. In the polycrystalline silicon manufacturing apparatus that exhausts the exhaust gas after the reaction from the exhaust gas discharge pipe to the outside of the reaction furnace, the source gas supply pipe and the exhaust gas discharge pipe are provided in a state of penetrating the bottom plate portion of the reaction furnace, The upper end exposed in the reactor is a double-pipe structure consisting of an inner pipe through which source gas or exhaust gas flows and an outer pipe that forms a ring-shaped space for circulating cooling water around the inner pipe. An end plate that closes the ring-shaped space is provided at a portion, and a circulation channel that guides cooling water along the circumferential direction on the back side of the end plate is provided between the end plate and the ring-shaped space. Ward Guide means for forming is provided on the outer pipe, wherein the outlet is formed for discharging the cooling water passing through the circulation flow path from the outer pipe.

  In this polycrystalline silicon manufacturing apparatus, the cooling water supplied from the lower side to the upper side in the ring-shaped space between the inner pipe and the outer pipe is guided into the circulation channel by the guide means, and the circulation channel Wrap around in contact with the back of the end plate. Therefore, no air pocket is formed below the end plate, and the end plate and the upper end portions of both pipes are effectively cooled by the cooling water that is always circulated.

Further, in the polycrystalline silicon manufacturing apparatus of the present invention, the guide means includes an arc plate disposed in the ring-shaped space at a distance from the end plate along the circumferential direction, one end of the arc plate, and the A partition member that is closed between the end plate and spaced from the other end of the arc plate, and is surrounded by the end plate and the arc plate The said discharge port is good to open to the path.
The circular flow path is formed by an arc plate and a partition member below the end plate, and with an extremely simple structure, the cooling water is circulated to reliably cool the upper ends of the source gas supply pipe and the exhaust gas discharge pipe. be able to.

In the polycrystalline silicon manufacturing apparatus of the present invention, the bottom plate portion of the reactor is formed in a double structure in which an upper plate and a lower plate are arranged with a space between each other, and cooling water is provided between these two plates. It is preferable that a circulating furnace bottom space is formed and the discharge port is opened in the furnace bottom space.
Since the cooling water also circulates in the bottom plate part through which the raw material gas supply pipe and the exhaust gas discharge pipe penetrate, it is possible to prevent heat from being transmitted from the bottom plate part to the raw material gas supply pipe and the exhaust gas discharge pipe. Cooling water passing through the double pipe is discharged to the furnace bottom space in the bottom plate and can be used for cooling the bottom plate.

Further, in the polycrystalline silicon manufacturing apparatus of the present invention, an outer discharge port for discharging cooling water from the furnace bottom space portion to the outside is provided on the outer peripheral portion of the bottom plate portion, and the discharge port of the circulation channel is It is good to arrange | position toward the radial direction inner side of the said baseplate part.
In the furnace bottom space in the bottom plate portion, the cooling water is once circulated radially inward, and then flows radially outward and is discharged to the outside from the outer furnace outlet of the outer periphery. Therefore, the cooling water spreads to every corner including the central portion in the bottom plate portion, and the cooling effect of the bottom plate portion can be further enhanced.

  According to the polycrystalline silicon manufacturing apparatus of the present invention, the circulating flow by the guide means between the inner pipe and the upper end of the outer pipe in the source gas supply pipe and the exhaust gas discharge pipe and the end plate that closes the ring-shaped space therebetween. Since the path is formed and the cooling water that has been supplied upward from below is circulated while contacting the back surface of the end plate in the circulation channel, no air pocket is formed below the end plate, The end plates and the upper end portions of both pipes are effectively cooled by the cooling water that always flows.

It is a perspective view which notches and shows a part of upper end part of the raw material gas supply pipe (or exhaust gas discharge pipe) in the polycrystalline silicon manufacturing apparatus of one Embodiment of this invention. It is a perspective view in the state where a bell jar of a reaction furnace in a polycrystalline silicon manufacturing device of one embodiment was partially cut off. It is a longitudinal cross-sectional view which expands and shows the baseplate part of the reaction furnace of FIG. FIG. 4 is an enlarged longitudinal sectional view showing a pipe penetration part of the bottom plate part of FIG. 3. It is a top view which shows the distribution | circulation direction of the cooling water in the furnace bottom space part of the bottom plate part of FIG.

Hereinafter, an embodiment of a polycrystalline silicon production apparatus of the present invention will be described with reference to FIGS.
FIG. 2 is an overall view of the polycrystalline silicon manufacturing apparatus. A reaction furnace 1 of the polycrystalline silicon manufacturing apparatus includes a bottom plate portion 2 constituting a furnace bottom, and a bell mounted on the bottom plate portion 2 in a detachable manner. And a shaped bell jar 3.
The bottom plate portion 2 includes a plurality of electrodes 5 to which a silicon core rod 4 serving as a seed rod for polycrystalline silicon is attached, and an ejection nozzle 6 for ejecting a source gas containing chlorosilane gas and hydrogen gas into the furnace. A plurality of raw material gas supply pipes 7 (see FIG. 3) and a plurality of exhaust gas discharge pipes 9 each provided with a discharge port 8 for discharging the reacted gas outside the furnace are provided. In FIG. 3, the code | symbol 10 has shown the support member of the electrode 5 provided in the bottom plate part 2 in the penetration state. In FIG. 3, only one raw material gas supply pipe 7, exhaust gas discharge pipe 9, and support member 10 are shown for simplification.

  In addition, the source gas ejection nozzles 6 are dispersed over almost the entire upper surface of the bottom plate portion 2 of the reaction furnace 1 so as to supply the source gas uniformly to the silicon core rods 4 at appropriate intervals. There are multiple installations. These ejection nozzles 6 are connected to a source gas supply system 11 outside the reactor 1 via a source gas supply pipe 7. Further, a plurality of discharge ports 8 are installed in the vicinity of the outer peripheral portion of the bottom plate portion 2 with appropriate intervals, and are connected to an external exhaust gas treatment system 12 via an exhaust gas discharge pipe 9.

  Each electrode 5 is arranged substantially concentrically at a predetermined interval on the bottom plate portion 2, and is erected vertically in the support member 10 of the bottom plate portion 2, and is connected to an external power source 13. Has been. Each electrode 5 is formed with a hole (not shown) along the vertical direction, and the lower end portion of the silicon core rod 4 is attached to the hole in the inserted state. Note that the two silicon core rods 4 are assembled at the upper end portion by the same silicon connecting member 14 and assembled in the shape of a letter.

As shown in FIG. 3, the bottom plate portion 2 is a double plate in which a furnace bottom space portion 17 having a predetermined height is formed between an upper plate 15 and a lower plate 16 that are spaced apart from each other and provided substantially horizontally. A cooling water is circulated in the furnace bottom space 17 as will be described later. Further, as described above, the raw material gas supply pipe 7 and the exhaust gas discharge pipe 9 are provided in the bottom plate portion 2 together with the support member 10 of the electrode 5 in a penetrating state.
Hereinafter, although the structure of the penetration part of these source gas supply pipes 7 and exhaust gas discharge pipes 9 will be described, both the source gas supply pipe 7 and the exhaust gas discharge pipe 9 have substantially the same basic structure for the penetration parts. Hereinafter, these through portions will be described with reference to the same drawings (FIGS. 1 and 4).

As shown in FIGS. 1 and 4, the raw material gas supply pipe 7 and the exhaust gas discharge pipe 9 are formed in a double tubular shape including an inner pipe 21 and an outer pipe 22 having the same axis, and the raw material gas is supplied to the inner pipe 21. Gas flows, and cooling water is supplied and circulated in a ring-shaped space 23 between the inner pipe 21 and the outer pipe 22 from a cooling water supply system 24 (see FIG. 3) connected to the outer pipe 22. It is a configuration. A ring-shaped end plate 25 that closes the ring-shaped space 23 is provided on the upper end surface between the inner pipe 21 and the outer pipe 22, and the upper end projects from the upper surface of the bottom plate 2. Exposed to the state.
A guide means 26 is provided in the ring-shaped space 23 between the pipes 21 and 22 to guide the cooling water rising from below along the circumferential direction of the ring-shaped space 23 at a position below the end plate 25. ing.

The guide means 26 is arranged along a circumferential direction in a part of the ring-shaped space 23 and forms a circular flow path 27 between the end plate 25 and an end connected to one end of the arc plate 28. A guide box 30 is provided which forms a lead-out flow path 29 that is bent downward from the circular flow path 27 while closing the space between the plate 25 and the plate 25.
The arc plate 28 has a form in which a part of the ring plate is cut out, and an inner peripheral edge thereof is bonded to the outer peripheral surface of the inner pipe 21 and an outer peripheral edge is bonded to the inner peripheral surface of the outer pipe 22. A guide box (corresponding to a partition member of the present invention) 30 is between a vertical plate 31 extending vertically and radially so as to bend downward from one end of the arc plate 28 and both ends of the arc plate 28. A partition plate 32 arranged in the vertical direction and along the radial direction and having an upper end in contact with the back surface of the end plate 25 and a lower ring-shaped space 23 connected to each other by connecting the lower ends of the vertical plate 31 and the partition plate 32 to each other. It is composed of a horizontal plate 33 that partitions the outlet channel 29.

  Therefore, the guide box 30 has the partition plate 32 disposed with a gap between the other end of the arc plate 28, so that the gap portion serves as an inlet 34 to the circulation channel 27. A portion surrounded by the vertical plate 31, the partition plate 32, and the horizontal plate 33 of the guide box 30 is a lead-out flow path 29, and a cooling water discharge port is formed on the tube wall of the outer pipe 22 facing the lead-out flow path 29. 35 is formed. The discharge port 35 is disposed in the furnace bottom space portion 17 between the upper plate 15 and the lower plate 16 of the bottom plate portion 2 at a position below the upper end of the outer pipe 22 and opens toward substantially the center of the bottom plate portion 2. The cooling water is discharged radially inward of the bottom plate portion 2.

  By configuring the guide means 26 in this manner, the cooling water that has risen in the ring-shaped space 23 enters the circulation channel 27 from the introduction port 34, flows through the circulation channel 27 in the circumferential direction, and then guides. The radial direction of the bottom plate portion 2 is guided to the lead-out flow path 29 of the box 30 and enters the furnace bottom space portion 17 between the upper plate 15 and the lower plate 16 of the bottom plate portion 2 from the discharge port 35 of the lead-out flow passage 29. It is discharged inward.

Further, as described above, the pipe penetration parts of the source gas supply pipe 7 and the exhaust gas discharge pipe 9 in the bottom plate part 2 of the reactor 1 have the same structure as described above, but the outlet 35 of each pipe penetration part. Are arranged toward the substantially center of the bottom plate portion 2 in the furnace bottom space portion 17 between the upper plate 15 and the lower plate 16 of the bottom plate portion 2. For this reason, as shown in FIG. 5, the cooling water is discharged from each discharge port 35 toward the center of the bottom plate portion 2.
On the other hand, as shown in FIGS. 3, 4 and 5, the outer peripheral wall of the bottom plate portion 2 is connected to an outside discharge port 36 for discharging cooling water from the inside of the furnace bottom space portion 17 to the outside. .

  In the polycrystalline silicon manufacturing apparatus configured as described above, the silicon core rod 4 disposed in the reaction furnace 1 is heated, and the source gas is supplied from the source gas supply pipe 7 to the surface of the silicon core rod 4. While depositing polycrystalline silicon, the exhaust gas after reaction is discharged out of the reaction furnace 1 from the exhaust gas discharge pipe 9. During the production of the polycrystalline silicon, cooling water is supplied from the cooling water supply system 24 to the ring-shaped space 23 between the inner pipe 21 and the outer pipe 22 of the source gas supply pipe 7 and the exhaust gas discharge pipe 9. The cooling water rises while cooling both the pipes 21 and 22 through the ring-shaped space 23, and then is introduced between the arc plate 28 of the guide means 26 and the guide box 30 at the upper ends of the pipes 21 and 22. As shown by the arrow A in FIG. In the circulation channel 27, cooling water flows in the circumferential direction between the circular arc plate 28 and the end plate 25, and the upper ends of both the pipes 21 and 22 including the end plate 25 are cooled therebetween. In this case, since the cooling water circulates in contact with the back surface of the end plate 25, no air pool is formed on the back side of the end plate 25, and the cooling water is always filled with the circulating cooling water. The upper end part of 22 can be cooled effectively.

  The cooling water that has circulated in the circulation channel 27 is then guided to the outlet channel 29 from the end of the circular arc plate 28 as shown by the arrow B in FIG. It is discharged radially inward into the furnace bottom space 17 between the plate 15 and the lower plate 16. When the cooling water is discharged from the discharge port 35 of each pipe penetration portion toward the inside in the radial direction of the bottom plate portion 2, the cooling water is circulated in the furnace bottom space portion 17 while the other pipe penetration portion ( The material gas supply pipe 7 or the exhaust gas discharge pipe 9) and the support member 10 of the electrode 5 are pushed to the outer peripheral portion of the bottom plate portion 2 while colliding with the support member 10, and are discharged out of the furnace through the outer discharge port 36 on the outer peripheral wall of the bottom plate portion 2. The

  As described above, in this polycrystalline silicon manufacturing apparatus, the source gas supply pipe 7 and the exhaust gas discharge pipe 9 that penetrate the bottom plate portion 2 of the reaction furnace 1 have a double-pipe structure, and an end plate 25 is provided at the upper end portion thereof. Since the circulation channel 27 is formed between the end plate 25 and the back surface of the end plate 25 is filled with cooling water, the upper end portion exposed in the reaction furnace 1 is effectively cooled without generating an air pocket. Can do. Further, the cooling water that has passed through the raw material gas supply pipe 7 and the exhaust gas discharge pipe 9 is discharged radially inward into the furnace bottom space 17 and circulated in the furnace bottom space 17. Therefore, the cooling water spreads to every corner including the central part in the furnace bottom space 17, and the cooling effect of the bottom plate part 2 can be enhanced.

  In addition, this invention is not limited to the thing of the structure of the said embodiment, In a detailed structure, a various change can be added in the range which does not deviate from the meaning of this invention. For example, in the above embodiment, the outlet channel is formed so as to be bent from the circulation channel by the guide box. However, the outlet channel may be omitted and the cooling water may be discharged from the end of the circulation channel. . In that case, what is necessary is just to block | close between the one end and end plate of a circular arc plate with a plate-shaped partition member.

DESCRIPTION OF SYMBOLS 1 Reactor 2 Bottom plate part 3 Berja 4 Silicon core rod 5 Electrode 6 Injection nozzle 7 Material gas supply pipe 8 Discharge port 9 Exhaust gas discharge rod 10 Support member 11 Material gas supply system 12 Exhaust gas treatment system 13 Power supply 14 Connection member 15 Upper plate 16 Lower plate 17 Furnace bottom space 21 Inner piping 22 Outer piping 23 Ring-shaped space 24 Cooling water supply system 25 End plate 26 Guide means 27 Circulating channel 28 Circular plate 29 Derived channel 30 Guide box (partition member)
31 Vertical plate 32 Partition plate 33 Horizontal plate 34 Inlet 35 Outlet 36 Out-of-furnace outlet

Claims (4)

A plurality of silicon core rods are heated in the reaction furnace, and polycrystalline silicon is precipitated around the silicon core rods by reaction of the source gas supplied from the source gas supply pipe, and the exhaust gas after the reaction is discharged into the exhaust gas discharge pipe. In the polycrystalline silicon production equipment that discharges from the reactor to the outside,
The source gas supply pipe and the exhaust gas discharge pipe are provided in a state of penetrating the bottom plate portion of the reactor, and an inner pipe through which the source gas or the exhaust gas flows and a ring for circulating cooling water around the inner pipe And an end plate that closes the ring-shaped space is provided at an upper end portion exposed in the reaction furnace, and the end plate is provided in the ring-shaped space. Guiding means for partitioning and forming a circulation channel for guiding cooling water along the circumferential direction on the back side of the plate is provided between the end plate, and the cooling water passing through the circulation channel is supplied to the outer pipe. An apparatus for producing polycrystalline silicon, wherein a discharge port for discharging from an outer pipe is formed.   The guide means closes the arc plate disposed in the ring-shaped space along the circumferential direction with a gap from the end plate, and closes between one end of the arc plate and the end plate. A partition member disposed with a gap between the other end of the first and second ends, and the discharge port is open in the circulation channel surrounded by the partition member, the end plate and the arc plate The polycrystalline silicon manufacturing apparatus according to claim 1.   The bottom plate portion of the reactor is formed in a double structure in which an upper plate and a lower plate are arranged with a space between each other, and a furnace bottom space portion through which cooling water flows is formed between these both plates, 3. The polycrystalline silicon manufacturing apparatus according to claim 1, wherein the discharge port is opened in the furnace bottom space. An outer discharge port for discharging cooling water from the furnace bottom space portion to the outside is provided on the outer peripheral portion of the bottom plate portion, and the discharge port of the circulation channel is arranged inward in the radial direction of the bottom plate portion. The polycrystalline silicon manufacturing apparatus according to claim 3, wherein the apparatus is a polycrystalline silicon manufacturing apparatus.

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