WO2010103632A1

WO2010103632A1 - Apparatus for producing trichlorosilane

Info

Publication number: WO2010103632A1
Application number: PCT/JP2009/054665
Authority: WO
Inventors: 靖史松尾; 晃一竹村; 誠松倉; 裕介和久田
Original assignee: 電気化学工業株式会社
Priority date: 2009-03-11
Filing date: 2009-03-11
Publication date: 2010-09-16
Also published as: TW201034954A; JP5442715B2; JPWO2010103632A1

Abstract

Disclosed is an apparatus for producing trichlorosilane, which comprises a reactor that is provided with a generally cylindrical reaction chamber wherein a reaction product gas containing trichlorosilane and hydrogen chloride is produced from a raw material gas containing tetrachlorosilane and hydrogen, a heater for heating the reaction chamber, and an outer cylindrical case which houses the reaction chamber and the heater and is in contact with the reaction chamber only at the bottom of the reaction chamber; a quenching tower for cooling the reaction product gas; a connection cylinder for connecting the reactor and the quenching tower; an extraction pipe generally perpendicularly connected to the outer circumferential surface of the reaction chamber and so arranged as to reach the quenching tower through inside of the connection cylinder for the purpose of guiding the reaction product gas from the reactor to the quenching tower; and a bellows pipe arranged substantially coaxially with the extraction pipe within the connection cylinder so as to cover the extraction pipe, while having one end joined to the inner circumferential surface of the connection cylinder and the other end joined to the outer circumferential surface of the extraction pipe.

Description

Trichlorosilane production equipment

The present invention is a trichlorosilane production apparatus that reacts tetrachlorosilane with hydrogen to convert to trichlorosilane, and is particularly resistant to distortion and breakage due to thermal expansion, excellent in recovery efficiency of trichlorosilane, and in conversion efficiency. Also relates to an excellent trichlorosilane production apparatus.

Trichlorosilane (SiHCl ₃ ) is a special material gas used for manufacturing semiconductors, liquid crystal panels, solar cells, and the like. In recent years, demand has been steadily expanding, and growth is expected as a CVD material widely used in the electronics field.

Trichlorosilane is produced by contacting tetrachlorosilane (SiCl ₄ ) and hydrogen (H ₂ ) to achieve the following thermal equilibrium state.
SiCl ₄ + H ₂ ⇔SiHCl ₃ + HCl (1)
This reaction is performed by heating a raw material gas composed of gasified tetrachlorosilane and hydrogen to 800 ° C. to 1300 ° C. in a reaction vessel.

The high temperature reaction product gas discharged from the reaction vessel contains a large amount of unreacted tetrachlorosilane and hydrogen in addition to the generated trichlorosilane and hydrogen chloride. In order to extract trichlorosilane from the reaction product gas, a method of condensing in a distillation column using the difference in boiling point between tetrachlorosilane and trichlorosilane is used. Specifically, in the condenser, it is divided into a chlorosilane that is a condensed component and hydrogen chloride, hydrogen, and an uncondensed chlorosilane that is an uncondensed component, and further cooled to about −70 ° C. by deep-cooling separation, and then trichlorosilane from the condensed component Isolate.

When separating the target trichlorosilane from the reaction product gas, if the high-temperature reaction product gas just introduced from the reaction vessel is suddenly introduced into the distillation column, an excessive load is applied to the distillation column. Before the reaction product gas is introduced into the distillation tower, it is necessary to preliminarily cool it in the quenching tower.

However, even if it is preliminary cooling, if the cooling power is insufficient, the equilibrium is inclined to the tetrachlorosilane side, and once generated trichlorosilane returns to tetrachlorosilane again. Therefore, in order to improve the recovery efficiency of trichlorosilane, it is necessary to cool the reaction product gas to a predetermined temperature as quickly as possible when the equilibrium has sufficiently reached the trichlorosilane side and freeze the equilibrium. In order to instantly freeze the equilibrium state, it is typically necessary to rapidly cool the reaction product gas to about 600 ° C. in less than one second.

As a reaction vessel equipped with a mechanism for reacting tetrachlorosilane with hydrogen to convert to trichlorosilane and further cooling the reaction product gas, there is one described in Patent Document 1, for example. According to the reactor described in this document, a heat exchanger is connected to the bottom of the reactor, and a raw material gas composed of hydrogen and chlorosilane preheated in the heat exchanger is supplied to the reactor. The supplied raw material gas moves up the outer chamber provided in the reactor and is heated by a heating element installed in the reactor. The gas generated by the heating is changed in the traveling direction by a diverter provided at the top of the reactor, proceeds through the inner chamber in the reactor toward the bottom, flows into the heat exchanger again, and in the heat exchanger, Heat is transferred from the heated reaction product gas to the raw material gas supplied into the reactor. As a result, the reaction product gas is cooled and the raw material gas is preheated.

Still another example is described in Patent Document 2. In this document, a supply gas containing tetrachlorosilane and hydrogen is supplied to generate a reaction product gas containing trichlorosilane and hydrogen chloride, a heating mechanism for heating the inside of the reaction vessel, A storage container for storing the reaction container and the heating mechanism, a gas supply inner cylinder for supplying a supply gas into the reaction container, an outer peripheral surface of the gas supply inner cylinder, and a self-inside of the gas supply inner cylinder. A gas exhaust outer cylinder in which an exhaust flow path for reaction product gas is formed between the peripheral surface and a cooling cylinder in which a refrigerant path for supporting the gas exhaust outer cylinder on the inside and through which a refrigerant flows is formed. A chlorosilane production apparatus has been proposed. In this trichlorosilane production apparatus, when the reaction product gas in a high temperature state is cooled from the outside by the refrigerant flowing in the cooling cylinder provided outside the gas exhaust outer cylinder when discharged through the exhaust passage. The gas supply inner cylinder provided inside the gas exhaust outer cylinder is cooled by exchanging heat with the supply gas flowing toward the inside of the reaction vessel. That is, the cooling efficiency is improved by simultaneously cooling from the inside and outside of the gas exhaust outer cylinder.

However, in the reactor described in Patent Document 1, since the cooling of the reaction product gas is left only to heat exchange with the adjacent raw material gas, the reaction product gas reaching 1000 ° C. or higher. It is difficult to cool the water to about 600 ° C. instantaneously. Therefore, until the reaction product gas is discharged, the above-mentioned equilibrium gradually tilts toward the tetrachlorosilane side, and a part of the trichlorosilane that has been generated is lost. Moreover, in the apparatus described in Patent Document 2, although a cooling cylinder having a refrigerant path formed around the gas exhaust outer cylinder is provided, in this case as well, the reaction product gas is cooled by the gas exhaust outer cylinder. Since it is entrusted to heat exchange via the inner wall and the outer wall, it is not necessarily sufficient in terms of cooling rate and capacity.

Furthermore, in the apparatus described in Patent Document 2, the bottom of the reaction vessel is closed by a lower support disc, and the lower support disc is a bottom support member that constitutes the bottom plate of the storage vessel only at the center thereof. Since it is supported by a support column member protruding upward from the center of the reaction tube, even if the reaction cylinder wall constituting the reaction vessel is thermally expanded, the lower support disk can be bent and deformed around the support column member, The stress can be absorbed. However, in the upper part of the reaction vessel, although the gas exhaust outer cylinder and the gas exhaust pipe through which the high-temperature reaction product gas passes are arranged, the upper part of the reaction vessel has the upper support disk, the gas supply inner cylinder and the upper part. It is supported and fixed in contact with the storage container by an annular plate and a gas exhaust outer cylinder. In other words, the gas exhaust outer cylinder and gas exhaust pipe through which high-temperature gas flows are supported and fixed to the storage container, top plate section, cooling cylinder, supply gas introduction section, etc., reducing stress concentration due to thermal expansion of the members It is not possible to cause distortion and breakage. In addition, since a low-temperature cooling cylinder is provided adjacent to the outer side of the gas exhaust outer cylinder, if the cooling capacity is increased too much, an excessive temperature difference is locally generated in each member constituting the part, and stress is reduced. Concentration may cause damage.

Therefore, as a method of cooling the reaction product gas more powerfully and instantaneously than the cooling method via the inner wall or outer wall of such an exhaust pipe, the reaction product gas is led out from the high-temperature reaction vessel to the quenching tower, where the reaction product gas A method has been proposed in which the coolant is brought into direct contact with the reaction product gas by using latent heat of vaporization when the coolant evaporates.

For example, Patent Document 3 discloses that a reaction product gas containing trichlorosilane and hydrogen chloride is obtained by introducing tetrachlorosilane and hydrogen into a reaction chamber and performing a conversion reaction at a temperature of 600 ° C. to 1200 ° C., and then from the reaction chamber. There has been proposed an apparatus provided with a cooling means for bringing the derived reaction product gas into contact with a chlorosilane mixture cooled to room temperature by spraying and rapidly cooling to 300 ° C. or less within 1 second.

JP-A-6-293511 JP 2008-133175 A Japanese Patent Publication No.57-38524

Summary of the Invention

By the way, in the apparatus described in Patent Document 3, the reaction furnace and the quenching tower are connected via a connection pipe provided on the side of the quenching tower, and the junction between the connection pipe and the reaction furnace is closed. An end is formed. Then, a sound is passed through the closed end, and the reaction gas generated in the reaction furnace is led to the quenching chamber through the sound.

However, the reactor wall that reaches the high temperature and the low-temperature quenching chamber are blocked by the closed end wall at the junction between the connecting pipe and the reactor, and therefore the end wall that blocks the quenching tower and the reactor. There is a large temperature difference locally in the vicinity of it. As a result, stress due to thermal expansion concentrates on the part, which may cause distortion or breakage. Moreover, even if the sound that penetrates and is fixed to the end wall surface is thermally expanded, stress may be concentrated on the joint between the sound and the end wall surface, resulting in distortion or breakage.

In other words, a system in which cooling liquid is directly sprayed on the reaction product gas to cool it instantaneously is excellent in quenching efficiency, but a large temperature difference is locally applied to the device, so how to avoid stress concentration due to thermal expansion. Is a problem. Nevertheless, Patent Document 3 does not mention any means for absorbing or alleviating the stress.

The present invention has been made in view of the above circumstances, and provides a trichlorosilane production apparatus that is less likely to be distorted or damaged due to thermal expansion, is excellent in trichlorosilane recovery efficiency, and is also excellent in trichlorosilane conversion efficiency. For the purpose.

The present invention employs the following configuration in order to solve the above problems. That is, the trichlorosilane production apparatus of the present invention is
A substantially cylindrical reaction vessel that generates a reaction product gas containing trichlorosilane and hydrogen chloride from a raw material gas containing tetrachlorosilane and hydrogen, a heater that heats the reaction vessel, the reaction vessel and a heater that contain the heater, and A reaction furnace comprising a reaction vessel and an outer cylindrical container that contacts only at the bottom of the reaction vessel;
A quenching tower for cooling the reaction product gas;
A connecting cylinder connecting the reactor and the quenching tower;
An extraction pipe connected to the outer peripheral surface of the reaction vessel substantially perpendicularly and arranged to reach the quenching tower through the inside of the connecting cylinder, and leading the reaction product gas from the reaction furnace to the quenching tower;
A bellows pipe disposed substantially coaxially so as to cover the extraction pipe inside the connection cylinder, having one end joined to the inner periphery of the connection cylinder and the other end joined to the outer periphery of the extraction pipe. It is characterized by.

<Preventing damage due to thermal expansion>
In this trichlorosilane production apparatus according to the present invention, the reaction vessel is stably housed in the reaction furnace with only the bottom thereof being in contact with the bottom of the outer tube vessel. Here, one end of the extraction tube is connected to the outer peripheral surface of the reaction vessel, but the extraction tube is held by a bellows tube that can be expanded and contracted inside the connecting cylinder, so that the reaction vessel is substantially fixed. It does not contribute and does not put excessive pressure on the reaction vessel. That is, the reaction container is housed in the outer cylinder container in a state where only the bottom part is in contact with the outer cylinder container, and is stably fixed to the bottom part of the outer cylinder container only by its own weight without using any fixing means. Therefore, stress concentration does not occur even if thermal expansion occurs due to heating.

Further, since the extraction pipe is held in a stretchable manner by a bellows pipe disposed substantially coaxially between the extraction pipe and the connection cylinder in the connection cylinder, the extraction pipe is heated and heated by the passage of the reaction product gas. Even if the bellows tube expands, the bellows tube expands and contracts following this, so that stress concentration can be avoided.

In addition, the bellows tube is configured not only to thermally expand the extraction tube but also to the reaction vessel by supporting the reaction vessel with its own weight only at its bottom while holding one end of the extraction tube in a stretchable manner. It can also be deformed following the thermal expansion. For this reason, it can deform | transform suitably also with respect to the thermal expansion of both reaction container and an extraction pipe, can absorb stress, and can protect the whole apparatus from a distortion and a failure | damage.

The bellows tube also serves as a blocking member that blocks the space inside the reactor and the space inside the quenching tower, but it can be freely deformed so that the airtight state between both towers can be maintained more stably. can do.

Further, in this trichlorosilane production apparatus, in order to lead the reaction product gas generated in the reaction vessel in the reaction furnace to the quenching tower through an extraction pipe connected substantially perpendicularly to the outer peripheral surface of the reaction vessel, The reaction vessel and quenching tower can be connected in a straight line with the shortest distance. Therefore, the extraction tube may be a substantially straight hollow tube, and does not need to have a complicated shape, and thus has excellent heat resistance. That is, even when the extraction tube is held by a bellows tube, if the extraction tube is bent, depending on the expansion and contraction strength of the bellows tube, the bent portion of the extraction tube or the connection portion with the reaction vessel However, in this trichlorosilane production apparatus, since the extraction pipe can be made to be a simple substantially straight line, local excessive stress is not applied to the extraction pipe. .

Furthermore, since the bellows pipe is arranged so as to cover the extraction pipe inside the connecting cylinder, an intermediate temperature band between both spaces can be formed in the region. That is, an intermediate temperature zone that gradually falls from the outer cylinder side to the quenching tower side is formed in the connecting cylinder, and the thermal load applied to the extraction pipe can be dispersed. Therefore, it is possible to prevent a large stress from being locally generated in the extraction pipe.

In this way, one end of the extraction pipe is held in a stretchable manner by the bellows pipe, and the reaction vessel is supported only by its own weight at the bottom thereof, so that both the reaction vessel and the extraction pipe exposed to high temperature It can freely expand or contract to avoid stress concentration and protect the entire device from distortion and breakage.

<Improvement of collection efficiency>
As described above, since the trichlorosilane manufacturing apparatus according to the present invention has extremely excellent resistance to the generation of stress, it can be used in combination with a quenching system with high cooling efficiency. Therefore, for example, it is particularly suitable for a rapid cooling system in which the coolant is directly sprayed on the reaction product gas taken into the quenching tower, and the heat is instantly removed using the latent heat of vaporization when the coolant is vaporized. ing. In this case, since the latent heat of vaporization accompanying the vaporization of the coolant is used, it is much more efficient than heat exchange with the refrigerant and supply gas through the wall forming the exhaust flow path of the reaction product gas. And it can cool economically.

In addition, the distance from the reaction vessel to the quenching tower can be minimized by connecting the extraction pipe substantially perpendicularly to the outer peripheral surface of the reaction vessel and arranging it straight as it is to reach the quenching tower. it can. For this reason, it can be supplied to the quenching tower in a short time while the equilibrium is inclined to the trichlorosilane side, and the amount of trichlorosilane lost by being cooled while the reaction product gas flows through the extraction pipe can be reduced.

Further, by adopting such a configuration, since the extraction tube is inserted into the quenching tower substantially horizontally, the reaction product gas is also ejected substantially horizontally. In general, in the method of spraying the cooling liquid on the reaction product gas, the cooling liquid is sprayed from the upper side of the quenching tower to the lower side. A circulation system is used that is pumped up to the top of the cooling tower and used again for spraying. In this trichlorosilane manufacturing apparatus, since the reaction product gas can be ejected substantially horizontally where the coolant is sprayed from the upper side to the lower side of the cooling tower, the reaction product gas and the coolant are substantially vertical. It can be made to collide. As a result, both can be mixed reliably and can be cooled efficiently. In addition, since the spraying direction of the cooling liquid is substantially perpendicular to the axial direction of the extraction pipe, the sprayed cooling liquid is less likely to flow into the extraction pipe. Can also be protected from corrosion.
Thus, since the reaction product gas in which the equilibrium is inclined to trichlorosilane can be instantaneously and efficiently cooled, the recovery efficiency of trichlorosilane can be greatly improved.

<Improvement of conversion efficiency>
In addition, since the reaction in which trichlorosilane is generated from tetrachlorosilane and hydrogen in the above formula (1) is an endothermic reaction, in order to improve the conversion efficiency of trichlorosilane, the heat inside the reaction vessel does not escape to any extent. It is necessary to do so.

In the trichlorosilane production apparatus according to the present invention, since the reaction vessel in which the conversion reaction of trichlorosilane is performed is in contact with the outer cylinder container only at the bottom of the reaction container, the contact area between the reaction container and the outer cylinder container is kept small. Can do. As a result, the transfer of heat from the reaction container to the outer cylinder container can be suppressed, and the escape of heat to the outside can be suppressed. For this reason, the conversion efficiency from tetrachlorosilane to trichlorosilane can be improved.

Thus, according to the trichlorosilane manufacturing apparatus according to the present invention, the reaction vessel is configured such that one end of the extraction tube is stretchably held by the bellows tube and the reaction vessel is supported only by its own weight at the bottom. And the extraction tube can freely expand or contract to avoid stress concentration, and the entire apparatus can be protected from distortion and breakage.

Therefore, it can be used together with a rapid cooling system with high cooling efficiency as the heat resistance is improved, and trichlorosilane can be recovered much more efficiently than before without damaging the equipment. Furthermore, by adopting the above configuration, heat leakage from the reaction vessel to the outside is suppressed, so that the conversion efficiency of trichlorosilane can be improved.
Thus, the productivity of trichlorosilane can be improved by simultaneously improving the heat resistance stability, recovery efficiency, and conversion efficiency.

It is explanatory drawing of the trichlorosilane manufacturing apparatus which is embodiment of this invention. It is a schematic longitudinal cross-sectional view of the connection cylinder periphery of the trichlorosilane manufacturing apparatus which is embodiment of this invention. It is a schematic longitudinal cross-sectional view which shows one embodiment of the reaction container which can be used by this invention.

Explanation of symbols

1: Reaction furnace 2: Extraction pipe 3: Connecting cylinder 4: Rapid cooling tower 10: Reaction vessel 11: Heater 12: Outer cylinder vessel 13: Raw material gas inlet 14: Reaction product gas outlet 15: Heating element 16: Electrode 17 : Raw material gas introduction opening 18: Reaction product gas extraction opening 19: Tubular protrusion 21: First member 22: Second member 23: Third member 24: Reaction product gas blowing part 25: Projection 30: Bellows tube 31: Plate material 40: Metal container 41: Spray nozzle 42: Reaction product gas introduction opening 51: Substantially cylindrical body 52: Ring

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

FIG. 1 schematically shows an embodiment of a trichlorosilane production apparatus according to the present invention. FIG. 2 schematically shows a cross section around the connecting cylinder of the trichlorosilane production apparatus.

As shown in FIG. 1 and FIG. 2, the trichlorosilane production apparatus of this embodiment is
A substantially cylindrical reaction vessel 10 for generating a reaction product gas containing trichlorosilane and hydrogen chloride from a raw material gas containing tetrachlorosilane and hydrogen, a heater 11 for heating the reaction vessel 10, the reaction vessel 10 and the heater A reaction furnace 1 comprising an outer cylindrical container 12 that contains 11 and contacts the reaction container 10 only at the bottom of the reaction container 10;
A quenching tower 4 for cooling the reaction product gas;
A connecting cylinder 3 connecting the reactor 1 and the quenching tower 4;
An extraction pipe 2 connected substantially perpendicularly to the outer peripheral surface of the reaction vessel 10 and arranged to reach the quenching tower 4 through the connecting cylinder 3 and leads the reaction product gas from the reaction furnace 1 to the quenching tower 4. When,
A bellows pipe 30 disposed substantially coaxially in the connecting cylinder 3 so as to cover the extraction pipe 2, one end joined to the inner periphery of the connection cylinder 3, and the other end joined to the outer periphery of the extraction pipe 2; It has.

<Reactor>
The reaction furnace 1 includes a reaction vessel 10, a long heater 11 disposed so as to surround the outside of the reaction vessel 10, and the outer vessel 12 that accommodates the reaction vessel 10 and the heater 11. By heating the outer wall of the reaction vessel 10 with the heater 11 inside the heat-insulated outer cylinder 12, the inside of the reaction vessel 10 is kept at a high temperature of about 800 ° C. to about 1300 ° C., and the raw material gas provided at the bottom of the reaction vessel 10 A mixed gas of tetrachlorosilane and hydrogen supplied from the inlet 13 is reacted inside the reaction vessel 10 to generate a reaction product gas containing trichlorosilane and hydrogen chloride.

<Reaction vessel>
The reaction vessel 10 is a substantially cylindrical vessel for reacting tetrachlorosilane and hydrogen in a high temperature environment, and is connected to a raw material gas inlet 13 for taking in a raw material gas and an extraction pipe 2 described later. A reaction product gas outlet 14 for deriving the reaction product gas; In the present embodiment, the raw material gas inlet 13 is provided in the center of the bottom of the reaction vessel 10, and the reaction product gas outlet 14 is provided on the outer peripheral surface above the reaction vessel 10.
The source gas inlet 13 has a configuration in which the periphery of the opening extends substantially perpendicularly from the bottom to form a tubular projecting portion 19 and is fitted to a source gas introduction opening 17 provided at the bottom of the outer cylinder container 12 to be described later. Has been.

It is preferable that the inner peripheral surface and / or the outer peripheral surface of the reaction vessel 10 is treated with a silicon carbide coating. Since the silicon carbide coating has a very high resistance to chemical degradation, chemical erosion of the carbon structure can be prevented. Therefore, the surface of the reaction vessel 10 can be protected from corrosion by performing the silicon carbide coating treatment.

<Heater>
The heater 11 includes a plurality of elongated carbon heating elements 15 extending in the vertical direction and an electrode 16 connected to one end of the heating element 15 for supplying power to the heating element 15. The heater 11 is arranged so as to surround the reaction vessel 10 in a plurality, and controls the temperature inside the reaction vessel 10 from the outside of the reaction vessel 10 by controlling the amount of power supplied.

<Outer cylinder container>
The outer cylinder container 12 is a substantially cylindrical container whose outer side is made of a metal such as stainless steel and whose inner side is covered with a heat insulating material such as a carbon board, a refractory brick, or a heat insulating brick. The outer cylinder container 12 accommodates the reaction container 10 and the heater 11 and insulates them from the outside. When the reaction vessel 10 is accommodated in the outer cylinder vessel 12, the source gas introduction opening 17 and the reaction product gas extraction opening 18 are respectively located at positions corresponding to the source gas introduction port 13 and the reaction product gas extraction port 14. Is provided. The reaction product gas extraction opening 18 is provided with joint means such as a flange, and can be connected to a connecting cylinder 3 described later.

The diameter of the source gas introduction opening 17 is substantially the same as the outer diameter of the tubular projection 19 so that the tubular projection 19 formed as the source gas introduction port 13 is fitted to the bottom of the reaction vessel 10. .
When the reaction container 10 is accommodated in the outer cylinder container 12, the tubular protrusion 19 provided at the bottom of the reaction container 10 is fitted into the source gas introduction opening 17 provided at the bottom of the outer cylinder container 12. The reaction vessel 10 is positioned so as to secure an inflow path for the source gas, and at the same time, the reaction vessel 10 is stably fixed to the bottom of the outer cylinder vessel 12 by its own weight.

<Connecting cylinder>
The connecting cylinder 3 has joint means connected to the reaction furnace 1 at one end and joint means connected to the quenching tower 4 at the other end. The connection cylinder 3 according to the present embodiment is made of a metal such as stainless steel, and has a flange that can be connected to the reaction product gas extraction opening 18 of the outer cylinder container 12 at one end as shown in FIG. Has a flange for connection to a reaction product gas introduction opening 42 of the quenching tower 4 to be described later.

<Quenching tower>
The quenching tower 4 includes a cylindrical metal container 40, a spray nozzle 41 that is installed in the container and sprays the coolant in the container, and the coolant accumulated in the bottom of the container is taken out and circulated to the spray nozzle 41. A pump (not shown) for cooling, a cooling device (not shown) for cooling the coolant, and a conduit (not shown) for taking out the reaction product gas after cooling from the top of the quenching tower 4. A reaction product gas introduction opening 42 for connecting the connecting cylinder 3 is provided on the side wall of the quenching tower 4. The reaction product gas introduction opening 42 has a flange or the like for connecting to the connection cylinder 3. Joint means are provided. The spray nozzle 41 is installed in the vicinity of the upper part of the reaction product gas introduction opening 42 so that the coolant can be sprayed from above to the reaction product gas introduced into the quenching tower 4.

The cooling liquid used for cooling the reaction product gas is composed of, for example, a mixed liquid of trichlorosilane and tetrachlorosilane, and the ratio of tetrachlorosilane to the total amount of tetrachlorosilane and trichlorosilane should be 1 to 0.5. it can. The temperature is preferably 60 ° C. or lower. For example, a tetrachlorosilane: trichlorosilane composition ratio of 85:15 and a temperature of about 40 ° C. can be preferably used.

The cooled reaction product gas taken out from the top of the quenching tower 4 is further sent to a distillation tower through a conduit, and the target trichlorosilane is separated.

<Extraction pipe>
The extraction pipe 2 is a linear tubular member made of carbon that connects the inside of the reaction vessel 10 and the inside of the quenching tower 4 via the inside of the connecting cylinder 3, and the reaction product gas in the reaction vessel 10 is led to the quenching tower 4. To do.

The material constituting the extraction pipe 2 is a graphite material having excellent airtightness, and particularly has high strength due to the fine particle structure, and has the same characteristics such as thermal expansion in any direction. It is preferable to use isotropic high-purity graphite that is also excellent in corrosion resistance.

In particular, it is preferable that the inner peripheral surface and / or the outer peripheral surface of the extraction pipe 2 is treated with a silicon carbide coating, and that the silicon carbide coating is formed with a thickness of 10 to 500 μm by a CVD method. Since the silicon carbide coating has a very high resistance to chemical degradation, chemical erosion of the carbon structure can be prevented. Therefore, the surface of the extraction pipe 2 can be protected from corrosion by performing the silicon carbide coating treatment.

The extraction pipe 2 of the present embodiment is composed of a plurality of members, and when the apparatus is assembled, the first member 21 mainly located in the reaction furnace 1 and the second member mainly located in the connecting cylinder 3. 22 and a third member 23 mainly located in the cooling tower. That is, the first member 21 has a connecting portion with one end of the reaction product gas outlet 14 of the reaction vessel 10 at one end and a joint means for connecting the second member 22 at the other end. The joint member for connecting the first member 21 or the third member 23 is connected to both ends, and the third member 23 has the joint means for connecting the second member 22 to one end, and the reaction is generated at the other end. A gas blowing part 24 is provided.

The joint means of the extraction pipe 2 is formed with a protruding portion 25 on the outer peripheral side of the extraction pipe 2 so that a bellows pipe 30 described later can be joined. As a joint means for forming such a protrusion 25, a flange can be typically used. Alternatively, a substantially cylindrical tubular member may be used and the butted end portion may be screwed and fastened from the outside with a ring. In this case, the ring forms a protrusion 25 for joining the bellows tube 30.

<Bellows tube>
The bellows tube 30 is a member having a bellows structure made of metal, and can be expanded and contracted in the axial direction and can also be deformed in the radial direction. The bellows tube 30 may be made of metal, but is more preferably made of stainless steel, and may be made of austenitic stainless steel or ferritic stainless steel.

The bellows pipe 30 preferably has a mountain height of about 2 to 10% of the inlet diameter and a distance between the mountains of about 2 to 8% of the total length. Further, it is preferable that the amount of displacement in the axial direction is 3 to 10% of the inlet diameter, and the amount of displacement in the direction perpendicular to the shaft is about 2 to 5% of the total length. Further, the intervals and heights of the peaks may be uniform or non-uniform.

The bellows pipe 30 is arranged substantially coaxially so as to cover the outside of the extraction pipe 2 inside the connection cylinder 3, one end is joined to the inner periphery of the connection cylinder 3, and the other end is connected to the outer periphery of the extraction pipe 2. Be joined.
In the present embodiment, the connection between the bellows tube 30 and the inner periphery of the connecting cylinder 3 is performed between the joint means provided in the reaction product gas extraction opening 18 of the outer cylinder container 12 and the joint means provided in the connecting cylinder 3. The doughnut-shaped plate material 31 is sandwiched between them, and one end of the bellows tube 30 is fixed to a portion of the plate material 31 protruding into the connecting tube 3. In addition, the connection between the bellows pipe 30 and the outer periphery of the extraction pipe 2 is to fix one end of the bellows pipe 30 to the flange used to connect the second member 22 and the third member 23 that constitute the extraction pipe 2. Is done by.
The bellows pipe 30 holds the extraction pipe 2 in an extendable manner, and hermetically blocks the high temperature space inside the reaction furnace 1 and the low temperature space inside the quenching tower 4.

<Production and recovery of trichlorosilane>
In the trichlorosilane production apparatus of the present embodiment, a raw material gas composed of tetrachlorosilane and hydrogen is supplied to the reaction vessel 10 through a raw material gas inlet 13 located at the bottom of the reaction furnace 1, where about 800 to 1300 ° C. To be converted into trichlorosilane and hydrogen chloride. The reaction product gas containing trichlorosilane is led out to the quenching tower 4 through the extraction pipe 2 connected to the reaction product gas outlet 14 of the reaction vessel 10 and directly contacts the coolant sprayed from above the quenching tower 4. -It is mixed and the latent heat of vaporization accompanying the evaporation of the coolant is taken away, and it is instantly cooled to about 600 ° C. Thereafter, the reaction product gas is further cooled as necessary, and then taken out from the head of the quenching tower 4 and subjected to separation of trichlorosilane.

In the present embodiment, the reaction vessel 10 is housed in the outer tube vessel 12 with only the bottom thereof in contact with the outer tube vessel 12, and is fixed to the bottom of the outer tube vessel 12 only by its own weight. It can be freely expanded without restriction. Further, since the extraction pipe 2 is held in a stretchable manner by a bellows pipe 30 disposed between the extraction pipe 2 and the connection cylinder 3 in the connection cylinder 3 so as to be substantially coaxial therewith, the expansion pipe 2 is freely thermally expanded. can do.

Further, the bellows tube 30 is not only the extractor tube 2 but also has a structure in which one end of the extractor tube 2 is stretchably held by the bellows tube 30 and the reaction vessel 10 is supported only by its own weight at the bottom thereof. The reaction vessel 10 can expand and contract following the thermal expansion. For this reason, the bellows tube 30 can absorb any stress generated in the reaction vessel 10 and the extraction tube 2, and can protect the entire apparatus from distortion and breakage.

Further, since the bellows tube 30 blocks the space inside the reactor 1 and the space inside the quenching tower 4, the blocking member is not distorted or damaged due to thermal expansion, and the airtight state between both towers is maintained more stably. can do.
Furthermore, the bellows pipe 30 is arranged inside the connecting cylinder 3 so as to cover the extraction pipe 2, and the space in the high temperature outer cylinder container 12 and the space in the low temperature quenching tower 4 are connected via the bellows pipe 30. Therefore, an intermediate temperature zone can be formed in the connecting cylinder 3 along the bellows tube 30. Therefore, the thermal load applied to the extraction pipe 2 can be dispersed, and it is possible to prevent a large stress from being locally generated in the extraction pipe 2.

Further, in the present embodiment, as described above, since it has extremely excellent resistance to the generation of stress, the apparatus is hardly damaged even when used in combination with a rapid cooling system having a high cooling efficiency. Further, since the extraction pipe 2 linearly connects the reaction vessel 10 to the quenching tower 4 at the shortest distance, the reaction product gas can be fed into the quenching tower 4 while the equilibrium is inclined to the trichlorosilane side. The disappearance of trichlorosilane can be suppressed. In particular, since the reaction product gas can be applied substantially perpendicularly to the coolant to be sprayed, the reaction product gas can be instantaneously and efficiently cooled.

In addition, since the reaction vessel 10 in which the conversion reaction of trichlorosilane is performed is in contact with the outer cylinder vessel 12 only at the bottom of the reaction vessel 10, the contact area between the reaction vessel 10 and the outer cylinder vessel 12 can be kept small. For this reason, the transmission of heat from the reaction vessel 10 to the outer cylinder vessel 12 can be suppressed, the escape of heat to the outside can be suppressed, and the conversion efficiency from tetrachlorosilane to trichlorosilane can be improved. .

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, the reaction vessel 10 is preferably integrally formed in order to achieve excellent durability and heat transfer efficiency. However, due to problems in manufacturing technology, a plurality of substantially cylindrical bodies are connected and integrated. May be used. As the reaction vessel 10 in which a plurality of substantially cylindrical bodies are connected and integrated, in particular, as shown in FIG. 3, a plurality of substantially cylindrical bodies 51 are arranged substantially coaxially up and down with their ends abutting each other. What is screwed and fastened with the ring 52 from the outside is preferable. By adopting such a structure, the structure of the substantially cylindrical body 51 can be simplified, and since a thin portion is not formed, it has excellent resistance to physical impact. In addition, since the end of one substantially cylindrical body 51 does not fit into the end of the other substantially cylindrical body 51 in the connecting portion, the substantially cylindrical body 51 is thermally expanded when used in a high temperature environment. Even so, it is possible to suppress cracks and cracks in the connecting portion that are caused by differences in the thermal expansion coefficients of the individual substantially cylindrical bodies 51. Therefore, the frequency of replacing the constituent members of the reaction vessel 10 is reduced, and the working efficiency of the apparatus can be improved.

Moreover, in the said embodiment, although it comprised so that the reaction furnace 1 side edge part of the bellows pipe | tube 30 might be connected to the connection cylinder 3, and the quenching tower 4 side edge part might be connected to the extraction pipe | tube 2, this was connected reversely It doesn't matter. That is, the connection between the bellows pipe 30 and the inside of the connecting cylinder 3 is performed between the joint means provided in the reaction product gas introduction opening 42 of the quenching tower 4 and the joint means provided in the connecting cylinder 3. 31 is sandwiched, and one end of the bellows tube 30 is fixed to a portion of the plate member 31 that protrudes into the connecting cylinder 3, and the connection between the bellows tube 30 and the outside of the extraction tube 2 constitutes the extraction tube 2. You may carry out by fixing the end of the bellows pipe | tube 30 to the protrusion part 25 formed in the connection part of the 1st member 21 and the 2nd member 22. FIG.

Furthermore, in the said embodiment, although the extraction pipe 2 is comprised from three members, if it consists of a single member, since it is excellent in heat resistance and physical strength, it is preferable. Further, depending on the scale of the apparatus, etc., it may be composed of more members.

Moreover, it is preferable that the connecting cylinder 3 that connects the reaction furnace 1 and the quenching tower 4 includes a bellows pipe having a bellows structure. In this case, the stress generated in the connecting cylinder 3 can be absorbed by the change in the shape of the bellows tube 30. Therefore, damage due to thermal expansion of the connecting cylinder 3 can be prevented, and the stability and safety of the device can be further enhanced.

Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto.

Example 1
Trichlorosilane was produced using the trichlorosilane production apparatus shown in FIGS. 1 to 3, and the presence or absence of distortion or breakage in the reaction vessel and the extraction tube was examined.

<Device description>
The following members were used for this apparatus.
Reaction vessel:
A substantially cylindrical carbon cylinder made of isotropic graphite having an outer diameter of 15 cm, a height of 10 cm, and a thickness of 3 cm. The outer peripheral surface extends 3.5 cm from the upper end and the outer peripheral surface extends 3.5 cm from the lower end. A plurality of carbon substantially cylindrical bodies provided with screw portions were prepared. Similarly, a male screw portion was provided on the outer peripheral surface of the end portion on the connection side for the upper end side substantially cylindrical body constituting the canopy portion of the reaction vessel and the lower end side substantially cylindrical body constituting the bottom plate portion of the reaction vessel.
Furthermore, a source gas introduction port having a diameter of 2.5 cm and a height of a tubular protrusion around the opening of 10 cm is provided at the center of the bottom plate of the substantially cylindrical body on the lower end side, and one substantially cylinder disposed above the body part of the reaction vessel. A reaction product gas outlet having a diameter of 1.6 cm was provided on the outer peripheral surface of the body.

Next, in order to form a silicon carbide coating on the inner and outer peripheral surfaces of these carbon cylinders, the carbon cylinders were installed in a CVD reactor, and the inside of the apparatus was replaced with argon gas. Heated to 1200 ° C. A mixed gas of trichloromethylsilane and hydrogen (molar ratio 1: 5) was introduced into the CVD reactor, and a silicon carbide film having a thickness of 200 μm was formed on the entire surface of the substantially carbon cylinder by the CVD method.

Next, a carbon ring made of isotropic graphite having an inner diameter of 15 cm, a vertical width of 7.5 cm, and a radial thickness of 3.6 cm, the male ring formed on the inner peripheral surface of the carbon substantially cylindrical body. A plurality of carbon rings each having a female thread portion to be screwed with the thread portion were prepared, and a silicon carbide coating was applied to the entire surface in the same manner as described above.
A reaction vessel was constructed using these carbon substantially cylindrical body and carbon ring.

Extraction pipe:
A carbon extraction tube constituted by linearly connecting three hollow tubes having flanges at the connecting end portions was used. For the carbon extraction tube, a silicon carbide coating was applied to the entire surface in the same manner as described above.
The assembled extraction tube had a total length of 40 cm and an outer diameter of 3 cm.

Bellows tube:
A stainless steel bellows tube having a total length of 11 cm, an inlet diameter of 4 cm, an axial displacement of 5%, and an axial displacement of 4% was used.

<Assembly of the device>
A tubular protrusion of the raw material gas inlet of the reaction vessel is provided in the outer cylindrical container provided with a heater inside and provided with a raw material gas introduction opening and a reaction gas extraction opening on the bottom and outer peripheral surface, respectively. The reaction container was accommodated so that the reaction product gas outlet of the reaction container and the reaction gas outlet opening of the outer cylinder could coincide with each other. Next, one end of the extraction pipe is inserted from the reaction gas extraction opening of the outer cylinder container, connected to the reaction product gas extraction outlet of the reaction container, one end of the bellows pipe is joined to the outer periphery of the extraction pipe, and the other end is connected It joined to the inner periphery of a connection pipe | tube, one end of the connection pipe | tube was connected to the reaction gas extraction opening part of an outer cylinder container, and the other end was connected to the reaction product gas introduction opening part of a quenching tower.

<Experimental conditions>
Using the above apparatus, the reaction gas of tetrachlorosilane and hydrogen (mole = 1: 1) is reacted at normal pressure at a reaction temperature of 1100 ° C. in the reaction furnace, and the reaction product gas is quenched through an extraction pipe. And cooled rapidly by spraying a coolant whose temperature was adjusted to 20 ° C. (trichlorosilane concentration: 20%). The temperature of the reaction product gas after cooling derived from the quenching tower was 30 ° C.

<Experimental result>
After this trichlorosilane production apparatus was continuously operated for 2000 hours, the apparatus was disassembled and the reaction vessel, the extraction pipe and the connecting cylinder were observed, and no distortion or breakage was observed in any of the members.

Comparative Example 1
A trichlorosilane production apparatus was prepared in the same manner as in Example 1 except that a cylindrical member (thickness: 2 mm) having no bellows structure was disposed instead of the bellows tube. This cylindrical member is made of the same material as the bellows pipe used in Example 1, and the joining method with the connecting cylinder or the extraction pipe is the same as that of Example 1.

When this trichlorosilane production apparatus was operated in the same manner as in Example 1, the apparatus was disassembled and the reaction vessel, the extraction pipe, the connecting cylinder, and the cylindrical member were observed. As a result, the extraction pipe and the cylindrical member were distorted. Admitted.

Comparative Example 2
The space on the reactor side and the space on the quenching tower side were blocked near the center of the connecting cylinder using a flat plate-like member (thickness: 2 mm) having an opening through which the extraction tube can penetrate instead of the bellows tube. Except for the above, a trichlorosilane production apparatus was prepared in the same manner as in Example 1 above. This flat plate member is made of the same material as the bellows tube used in the first embodiment.

When this trichlorosilane production apparatus was operated in the same manner as in Example 1, the apparatus was disassembled, and the reaction vessel, the extraction tube, the connecting cylinder, and the flat plate member were observed. The tube was distorted.

Comparative Example 3
The apparatus for producing trichlorosilane was the same as in Example 1 except that the heat insulating material of the outer cylinder container ceiling was thickly arranged so that the canopy of the reaction container was fixed in contact with the ceiling of the outer cylinder container. Arranged.

When this trichlorosilane production apparatus was operated in the same manner as in Example 1, the temperature of the outer surface of the ceiling portion of the outer cylinder vessel was increased by 30% compared to the case of Example 1, and the heat of the reaction vessel was exposed to the outside. It was confirmed that there was a leak. In addition, cracks were observed in the reaction vessel, and operation became impossible before reaching 2000 hours.

<Experimental considerations>
As is clear from the above comparative experiment, the entire end of the extraction tube is held by a bellows tube, and the reaction vessel is supported at its bottom by its own weight, thereby protecting the entire device from distortion and damage. We were able to. Moreover, since the contact area between the reaction vessel and the outer tube vessel is reduced, heat leakage from the reaction vessel to the outside can be suppressed, and the production efficiency of trichlorosilane can be improved.

In the above, this invention was demonstrated based on the Example. It is to be understood by those skilled in the art that this embodiment is merely an example, and that various modifications are possible and that such modifications are within the scope of the present invention.

Claims

A substantially cylindrical reaction vessel for producing a reaction product gas containing trichlorosilane and hydrogen chloride from a raw material gas containing tetrachlorosilane and hydrogen; a heater for heating the reaction vessel; and a reaction vessel containing the reaction vessel and the heater; Is a reaction furnace comprising an outer tube container that contacts only at the bottom of the reaction vessel;
A quenching tower for cooling the reaction product gas;
A connecting cylinder connecting the reactor and the quenching tower;
An extraction pipe connected substantially perpendicularly to the outer peripheral surface of the reaction vessel and arranged to reach the quenching tower through the inside of the connecting cylinder, and for extracting the reaction product gas from the reaction furnace to the quenching tower;
An apparatus for producing trichlorosilane, comprising: a bellows pipe disposed substantially coaxially so as to cover the extraction pipe inside the connection cylinder, one end joined to the inner periphery of the connection cylinder, and the other end joined to the outer periphery of the extraction pipe.
The apparatus for producing trichlorosilane according to claim 1, wherein a cooling liquid is sprayed on the reaction product gas in the quenching tower.
The apparatus for producing trichlorosilane according to claim 2, wherein the coolant is sprayed substantially perpendicularly to the reaction product gas.
4. A trichlorosilane production apparatus according to claim 1, wherein the extraction pipe is substantially linear.