KR20100115582A - Conversion reactor for making trichlorosilane gas - Google Patents

Abstract

PURPOSE: A reactor for making a trichlorosilane gas is provided to minimize a relative temperature for a heater about mixed gases of a trichlorosilane gas and a hydrogen gas to remove an additional reaction of the hydrogen gas about the heater, thereby manufacturing highly pure trichlorosilane. CONSTITUTION: A reactor for making a trichlorosilane gas includes a cylindrical casing(43), a heater(71), a guide heating unit(49), a heating medium(51), and a nozzle(69). The cylindrical casing provides a sealed internal space, transfers a trichlorosilane gas and a hydrogen gas to the bottom and guides them upward. The heater is installed inside the casing and is heated by magnetic energy transferred from the outside to heat the casing. The guide heating unit is installed outside the casing and generates a magnetic force varied by a current change applied from the outside to guide and heat the heater.

Description

Reactor for producing trichlorosilane gas {Conversion reactor for making trichlorosilane gas}

The present invention relates to a reactor for producing trichlorosilane gas.

The process of manufacturing polysilicon includes a process of reducing gaseous trichlorosilane in an atmosphere of hydrogen gas and depositing it on a heated element surface. However, a large amount of trichlorosilane gas during the deposition process has a problem that the gas is changed to by-products such as gaseous tetrachloride as it is dehydrogenated before hydrogen is lost.

It is preferable to recycle the by-products generated by the dehydrogenation, ie, tetrachlorosilane gas, to trichlorosilane gas and recycle it to the polysilicon production process. As a method for converting silane tetrachloride gas into trichlorosilane gas, a technique for mixing silane tetrachloride gas with hydrogen gas and applying high temperature heat in the state has been proposed.

1 is a view showing for explaining the configuration and problems of a conventional reaction apparatus for producing trichlorosilane.

As shown in the drawing, the conventional trichlorosilane production apparatus 11 includes a heat exchanger 27 accommodating heat exchange means therein and a sealed shell mounted on an upper portion of the heat exchanger 27 to provide a sealed space. (13), a heat insulation cover 15 installed inside the sealed shell 13, and a heating element positioned inside the heat insulation cover 15 and receiving heat from the outside through an electrode 25 to generate heat. (19).

In addition, inside the heating element 19, reaction zones 21a and 21b, which are composed of induction pipes 31a and 31b and end plates 23, are provided. The reaction zones 21a and 21b are spaces in which tetrachloride silane gas and hydrogen gas are mixed and heated.

The induction pipes 31a and 31b are two pipes having different diameters and are perpendicular to the top of the heat exchanger 27. Among the two guide pipes 31a and 31b, the guide pipe 31a having a smaller diameter is fitted inside the other guide pipe 31b, and the upper end of the outer guide pipe 31b is blocked by the end plate 23. Therefore, a reaction zone 21a is formed between the inner circumferential surface of the outer induction pipe 31b and the outer circumferential surface of the inner induction pipe 31a. The reaction zone 21a communicates with the inner reaction zone 21b located in the induction pipe 31a.

Therefore, the tetrasilane silane gas and hydrogen gas introduced through the pipe (not shown) provided in the heat exchanger 27 move the outer reaction zone 21a upward along the arrow a direction, and then into the inner reaction zone 21b. After entering and descending, exit out. The gas is heated while passing through the reaction zones 21a and 21b so that the tetrachlorosilane gas is converted into trichlorosilane gas.

On the other hand, the heating element 19 is a plate-shaped member made of a carbon fiber composite material, the heat generated by the electricity transmitted from the outside to pass through the reaction zone (21a, 21b) silane tetrachloride and hydrogen gas 800 ℃ to 1200 Heat to about ℃.

Therefore, the mixed gas of silane tetrachloride and hydrogen gas passing through the reaction zones 21a and 21b is heated by the heat of the heating element 19 to convert a portion of the tetrachlorosilane gas into trichlorosilane gas.

Reference numeral 29 is an insulator. The insulator 29 is made of quartz, glass, silicon nitride, or the like, and prevents electricity or heat transmitted to the heating element 19 from flowing to the outside. The insulator also serves to seal the inner space of the heating element 19. That is, the gas passing through the reaction zones 21a and 21b does not leak out of the heating element 19.

By the way, the conventional reaction apparatus for producing trichlorosilane gas has a problem in that mixing of silane tetrachloride gas and hydrogen gas is insufficient, and in particular, a short time for passing through the reaction zones 21a and 21b is very inefficient. In fact, since the tetrasilane silane gas and hydrogen gas pass through the heat exchanger 27 in a separate line, enter the reaction zone 21a, and are mixed while passing through the reaction zone, the molecular distribution evenly distributed inside the reaction zones 21a and 21b. There is a limit to having.

In addition, as described above, the silane tetrachloride gas and the hydrogen gas pass through the reaction zones 21a and 21b in the arrow a and b directions, but do not stay inside the reaction zone, and thus cannot receive heat efficiently from the heating element 19. The reaction is inefficient. Moreover, silane tetrachloride and hydrogen gas are in contact with the induction pipes 31a and 31b heated by the heating element 19, and the contact area with the induction pipes 31a and 31b is narrow so that the heat transfer efficiency is further increased. Insufficient

In addition, since the heating element 19 is spaced apart from the reaction zones 21a and 21b, in order to maintain the temperature inside the reaction zones 21a and 21b at 800 ° C to 1200 ° C, the heating element 19 is at least 1600 ° C or more. Must be heated to temperature. Maintaining the heating element 19 at the above temperature causes a chemical side reaction.

The chemical side reaction is a reaction that proceeds when hydrogen gas passing through the reaction zone 21a leaks out of the reaction zone 21a and comes into contact with the high temperature heating element 19. When hydrogen gas comes into contact with a heating element 19 made of a high temperature carbon fiber composite material or recrystallized hydrocarbon, a chemical reaction occurs to generate methane gas. The methane gas is mixed with the trichlorosilane gas after the reaction is completed, thereby reducing the purity of the trichlorosilane gas. Accordingly, a process of separating methane gas from trichlorosilane gas may be added.

On the other hand, the insulator 29 coupled to the upper and lower ends of the heating element 19 has a problem that the longer the use, the finer it can be opened from the heating element 19 by the expansion and contraction of the heating element. If a gap occurs between the heating element 19 and the insulator 29, hydrogen gas may leak out between the gaps.

Hydrogen gas leaked between the gaps in contact with the heat insulation cover 15 generates methane gas and of course corrodes the heat insulation cover itself. According to the corrosion, the thickness of the heat insulation cover 15 becomes thin.

In addition, when the leaked hydrogen gas is filled in the space 17 between the heat insulating cover 15 and the sealing shell 13 beyond the heat insulating cover 15, the heat inside the heat insulating cover 15 passes through the hydrogen gas having a high heat transfer rate. It may be lost outside the sealing shell 13 and the temperature of the sealing shell 13 is raised to be dangerous.

The present invention has been made to solve the above problems, the mixture of silane tetrachloride and hydrogen gas is very uniform, as well as excellent heat transfer efficiency overall high operating efficiency and low operating cost, silane tetrachloride and hydrogen gas It is an object of the present invention to provide a reaction apparatus for producing trichlorosilane gas having high purity of trichlorosilane produced because the side temperature of the heating element with respect to the mixed gas can be minimized so that the side reaction of hydrogen gas to the heating element hardly occurs.

Reactor for producing trichlorosilane gas of the present invention for achieving the above object,

Silane tetrachloride gas and hydrogen gas supplied from the outside are passed through therein to be mixed and heated to obtain silane trichloride gas through a conversion reaction. A cylindrical casing leading upwardly; A heating element installed inside the casing and heated by magnetic energy transferred from the outside to heat the casing; An induction heating unit installed outside the casing and inducing heating of the heating element by generating a magnetic force that is time-varying by a current change applied from the outside; A heating medium composed of inert inorganic particles introduced into the casing and heated by heat induced by the induction heating unit, and inert inorganic particles that heat the gas while flowing by an upward flow pressure of silane tetrachloride and hydrogen gas; Located in the lower portion of the casing and characterized in that it comprises a plurality of nozzles for ejecting the silane tetrachloride gas and hydrogen gas into the casing.

In addition, the lower portion of the casing is provided with a chamber for receiving the silane tetrachloride gas and hydrogen gas supplied from the outside therein, the nozzle is located between the chamber and the casing and the gas supplied to the chamber to the casing side upwards It is characterized by ejecting.

In addition, the outer side of the heating element is characterized in that it is further provided with a heat insulating material surrounding the heating element.

In addition, the upper portion of the casing is provided with an outlet for discharging the heated gas passing through the inside of the casing to the outside of the casing, characterized in that the outlet is provided with a filter for passing the gas.

In addition, the heating element is in the form of a cylinder, it characterized in that the graphite, silicon carbide coated graphite, quartz is made of one selected from graphite lined graphite.

In addition, the heating medium is made of any one of silicon oxide, silicon carbide, zirconium oxide, zirconium silicon composite oxide, or is characterized in that composed of two or more selected.

The reaction apparatus for producing trichlorosilane gas of the present invention made as described above has a very uniform mixing of silane tetrachloride gas and hydrogen gas, and in particular, has excellent heat transfer efficiency, high overall operating efficiency and low operating cost, and Since the relative temperature of the heating element to the mixed gas mixed with hydrogen gas can be minimized, the side reaction of the hydrogen gas to the heating element hardly occurs, so that the trichlorosilane with high purity can be produced.

Hereinafter, one embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a view showing the overall structure of changing the tetrachloride silane to trichlorosilane using a reaction apparatus for producing trichlorosilane gas according to an embodiment of the present invention.

As shown in the drawing, the reactor 41 for producing trichlorosilane gas according to the present embodiment converts the silane tetrachloride gas into trichlorosilane gas by heating by passing the silane tetrachloride gas and hydrogen gas delivered from the outside therein, It serves to deliver the internal gas after the conversion to the external hydrogen separator (61).

In the reactor 41 for producing trichlorosilane gas, an induction heating part 49 is used as a heating means. The induction heating unit 49 is connected to the external power source 59 through the controller 57 and is supplied with power from the power source to generate a time-varying magnetic force to generate a heating element to be described later.

In addition, the hydrogen separator 61 passes a gas discharged from the reactor 41 and serves to separate hydrogen in the gas. The hydrogen gas is separated by the hydrogen separator 61 and the remaining gas moves to the distillation column 63. The distillation column 63 separates trichlorosilane gas and tetrachlorosilane gas, and sends trichlorosilane gas to the storage tank 65. The trichlorosilane gas stored in the storage tank 65 is introduced into the silicon manufacturing process. In addition, the tetrachlorosilane gas stored in the other reservoir 67 is moved to the reaction apparatus 41 side and heated.

3 is a view for explaining the configuration and operation of the reaction apparatus 41 for producing trichlorosilane gas according to an embodiment of the present invention.

Referring to the drawings, the reaction apparatus 41 for producing trichlorosilane gas according to the present embodiment includes a casing 43 having an inner space and having a cylindrical shape, and having an upper and lower end blocked, and mounted inside the casing 43. Cylindrical heating element 71, a chamber 53 which is located below the casing 43 and temporarily stores the silane tetrachloride gas and hydrogen gas supplied from the outside, and between the chamber 53 and the casing 43 It is positioned and includes a plurality of nozzles 69 for injecting the gas inside the chamber 53 upward into the heating element (71).

In addition, a heating medium 51 is introduced into the heating element 71. The heating medium 51 is an inorganic particle having a large heat capacity and is mixed with the inside of the casing 43 by the flow pressure of the gas injected upward through the nozzle 69. The heating medium 51 transfers heat to the gas moving upward while performing the above-mentioned flow in the casing 43. The heat means heat that the heating medium 51 receives from the heating element 71. As the type of the heating medium 51, for example, silicon oxide, silicon carbide, zirconium oxide, zirconium silicon composite oxide, etc. may be selectively used.

A plurality of filters 55 are provided below the upper portion of the casing 43. The filter 55 is fixed to the outlet 43a provided on the upper surface of the casing 43, and serves to filter impurities of the gas discharged from the casing 43 to the outside.

In addition, the heat insulator 45 is provided outside the heating element 71. The heat insulating material 45 surrounds the heating element 71 and blocks the heat of the heating element 71 from being transferred to the outside.

In addition, the induction heating unit 49 is installed outside the casing 41. The induction heating unit 49 generates a time-varying magnetic force by the power delivered from the power source 59 so that the heating element 71 is induction heated.

The casing 43 takes the form of a cylinder and passes the gas to be treated therein. The gas to be treated is injected upward through the nozzle 69 and then moved upward to exit through the filter 55. In this embodiment, the casing 43 takes the form of a cylinder, but the type of the casing can be variously changed as necessary.

The heating element 71 installed inside the casing 43 is a cylindrical member having a predetermined thickness, and the heating element 71 is heated by the induction heating unit 49 and emits heat into the casing 43.

In particular, the maximum temperature of the heating element 71 is significantly lower than the heating element 19 of the conventional reactor (11 in FIG. 1), and is only 50 than the temperature required for the tetrasilane silane gas to react with hydrogen gas and convert to trichlorosilane. ℃ high. For example, if the ambient temperature required for the conversion reaction is 800 ℃ to 1200 ℃ the heating element 71 is to be maintained at 850 ℃ to 1250 ℃.

The material of the heating element 71 may selectively use graphite, graphite coated with silicon carbide, graphite lined with quartz.

In addition, the heating medium 51 is a series of inorganic particles that do not cause a chemical reaction by heat or gas. For example, silicon oxide, silicon carbide, zirconium oxide, zirconium silicon composite oxide, etc. may be selectively used. The particle size of the heating medium 51 may vary depending on the case, but if the average diameter is approximately 2mm or less. In addition, the input amount of the heating medium 51 introduced into the casing 43 is 1/10 to 3/5 of the height of the heating element 71 in a state in which the heating medium 51 is stacked inside the casing 43. Good enough.

On the other hand, as described above, the chamber 53 is provided below the casing 43. The chamber 53 is separated from the inner space of the casing 43 as a space for temporarily receiving gas such as hydrogen gas and tetrachlorosilane gas supplied from the outside. Hydrogen gas and tetrachlorosilane gas introduced into the chamber 53 are primarily mixed in the chamber 53 and then ejected upward into the casing 43 through the plurality of nozzles 69.

The chamber 53 is sealed to the outside. Accordingly, the hydrogen gas and the tetrasilane silane gas supplied into the chamber 53 through the hydrogen gas supply pipe 77 and the silane tetrachloride gas supply pipe 79 by the gas compressors 73 and 75 are the gas compressors 73 and 75. It is kept compressed under the ejection pressure of. The gas pumps 73 and 75 are pumps for supplying hydrogen gas and tetrachlorosilane gas to the chamber 53.

In some cases, the chamber 53 is not provided separately, and the hydrogen gas supply pipe 77 is directly connected to the nozzle 69 of about half, and the tetrachlorosilane gas supply pipe 79 is directly connected to the remaining nozzles 69. Of course you can.

The nozzle 69 serves to eject hydrogen gas and tetrachlorosilane gas supplied from the outside into the casing 43, and a plurality of nozzles 69 are regularly arranged at the bottom of the casing 43.

In particular, each nozzle 69 is provided with a nozzle tip 69a that allows the gas ejected upward from the nozzle 69 to rise in a tornado. By the action of the nozzle tip 69a, hydrogen gas and silane tetrachloride have a high pressure and high speed cyclone pattern flow. The heating medium 51 is swung in the casing 43 by the ejection energy of the hydrogen gas and the tetrasilane silane gas, and transfers heat of the heating element 71 to the mixed gas.

The hydrogen gas and the tetrachlorosilane gas may be heated by the heating medium 51, but may be heated in direct contact with the heating element 71 or by radiant heat emitted from the heating element 71.

In any case, the hydrogen gas and the silane tetrachloride have a strong cyclone flow by the action of the nozzle 69 and are perfectly mixed and heated in direct contact with the heating medium 51 to be heated rapidly. In particular, since a large number of particles constituting the heating medium 51 are in direct contact with the gas, the heat transfer area is so large that the gas can be quickly heated to the required temperature. In other words, the working time is very short.

The induction heating unit 49 provided on the outside of the casing 43 uses electromagnetic induction principle of high frequency current and has a plurality of coils 49a and receives power from an external power source 59 to form the inside of the casing 43. The heat generating element 71 is to generate heat. Of course, the controller 57 should be provided to control the operation of the induction heating unit 49. The controller 57 determines the magnetic force change characteristic of the induction heating unit 49 and serves to create the best reaction conditions.

The operation of the reaction apparatus 41 for producing trichlorosilane gas of the present embodiment having the above configuration is performed as follows. First, the controller 57 is controlled to cause the heating element 71 to emit heat at a temperature required for the conversion reaction.

In this state, the tetrasilane silane gas to be treated is blown into the casing 43 through the nozzle 69 together with the hydrogen gas. The gas ejected upward by the nozzle 69 flows the heating medium 51 and receives heat from the heating element 71 through the heating medium 51, or directly receives heat from the heating element 71. Reaction is converted into trichlorosilane gas.

The trichlorosilane gas and the part of the tetrachlorosilane gas and the surplus hydrogen gas which are not converted by the above process are blown out through the filter 55 to the outside of the casing 43, and the hydrogen separator (61 of FIG. 2) Pass through the distillation column (63 in FIG. 2). Hydrogen gas and tetrachlorosilane gas not converted through the above process is moved back to the reactor 41 and the above process is repeated.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

1 is a view showing for explaining the configuration and problems of a conventional reaction apparatus for producing trichlorosilane.

2 is a view showing the overall structure of changing the tetrachloride silane to trichlorosilane using a reaction apparatus for producing trichlorosilane gas according to an embodiment of the present invention.

3 is a view for explaining the configuration and operation of the reaction apparatus for producing trichlorosilane gas according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

11, 41: reactor 13: airtight shell 15: insulation cover

17: interspace 19: heating elements 21a, 21b: reaction zone

23: end plate 25: electrode 27: heat exchanger

29: insulator 31a, 31b: induction pipe 43: casing

43a: outlet 45: insulation 49: induction heating portion

49a: coil 51: heating medium 53: chamber

55: filter 57: controller 59: power

61: hydrogen separator 63: distillation tower 65,67: reservoir

69: nozzle 69a: nozzle tip 71: heating element

73, 75: gas pump 77: hydrogen gas supply pipe

79: silane tetrachloride gas supply pipe

Claims (6)

Silane tetrachloride gas and hydrogen gas supplied from the outside are passed through therein to be mixed and heated to obtain trichlorosilane gas through a conversion reaction, providing a sealed inner space and receiving the silane tetrachloride gas and hydrogen gas as a lower portion. A cylindrical casing leading upwardly; A heating element installed inside the casing and heated by magnetic energy transferred from the outside to apply heat to the casing; An induction heating unit installed outside the casing and inducing heating of the heating element by generating a magnetic force that is time-varying by a current change applied from the outside; A heating medium composed of inert inorganic particles introduced into the casing and heated by heat induced by the induction heating unit, and inert inorganic particles that heat the gas while flowing by an upward flow pressure of silane tetrachloride and hydrogen gas; Reaction apparatus for producing trichlorosilane gas located in the lower portion of the casing, comprising a plurality of nozzles for ejecting the silane tetrachloride gas and hydrogen gas into the casing. The method of claim 1, The lower portion of the casing is provided with a chamber for accommodating silane tetrachloride gas and hydrogen gas supplied from the outside therein, the nozzle is located between the chamber and the casing and to eject the gas supplied to the chamber upward to the casing side Reactor for producing trichlorosilane gas, characterized in that. The method according to claim 1 or 2, Reaction apparatus for producing trichlorosilane gas, characterized in that the outer portion of the heating element is further provided with a heat insulating material surrounding the heating element. The method according to claim 1 or 2, Reaction apparatus for producing trichlorosilane gas, characterized in that the upper portion of the casing is provided with a discharge port for passing the inside of the casing and discharge the heated gas to the outside of the casing, the discharge port is provided with a filter for passing the gas. The method of claim 1, The heating element takes the form of a cylinder, the reaction apparatus for producing trichlorosilane gas, characterized in that made of graphite, silicon carbide coated graphite, quartz-lined graphite selected from one of the selected. The method of claim 1, The heating medium is made of any one of silicon oxide, silicon carbide, zirconium oxide, zirconium silicon composite oxide, or a reaction apparatus for producing trichlorosilane gas, characterized in that composed of two or more selected.

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