KR20170032553A - Process for producing trichlorosilane - Google Patents

Abstract

The present invention relates to a method for producing trichlorosilane by using a gas-liquid-solid three-phase reaction. In a tubular reactor which alternately passes through a low temperature region and a high temperature region, a liquid silane-based compound containing tetrachlorosilane Is injected together with hydrogen or hydrogen and hydrogen chloride to react to produce trichlorosilane.

Description

{PROCESS FOR PRODUCING TRICHLOROSILANE}

The present invention relates to a process for producing trichlorosilane, and more particularly to a process for efficiently producing trichlorosilane from tetrachlorosilane by using a gas-liquid-solid three-phase reaction.

Trichlorosilane (SiHCl ₃ : TCS) is a compound useful as a raw material for producing a high-purity polycrystalline silicon (also referred to as polysilicon), and is used for precipitating high-purity polysilicon by reacting with hydrogen at a high temperature of 1000 ° C. or higher. This reaction is mainly represented by the following reaction formulas (1) and (2).

₄ SiHCl ₃ ? Si + ₃ SiCl ₄ + 2H ₂ (1)

SiHCl ₃ + H ₂ ? Si + 3HCl (2)

The trichlorosilane used in the polysilicon precipitation reaction is generally prepared by the reaction of metal silicon with hydrogen chloride. For example, Patent Document 1 discloses a method of producing trichlorosilane by a reaction of the following reaction formula (3) by reacting metal silicon and hydrogen chloride in the presence of an iron- and aluminum-containing catalyst using a fluidized bed reactor .

Si + 3HCl -> SiHCl ₃ + H ₂ (3)

The gas produced by the reaction of metal silicon with hydrogen chloride is cooled to below -10 ° C to condense and separate trichlorosilane, which contains other byproducts of chlorosilane in addition to trichlorosilane. Trichlorosilane is separated and recovered from the condensate containing these chlorosilanes by distillation and used as raw materials for producing polysilicon. Further, tetrachlorosilane (SiCl ₄ : STC) separated by distillation is mainly converted to trichlorosilane (TCS) by the reaction of the following formula (4) and reused for the production of polysilicon.

3 SiCl ₄ + 2H ₂ + Si? 4 SiHCl ₃ (4)

On the other hand, in Patent Document 2, metal silicon particles, hydrogen chloride, tetrachlorosilane and hydrogen having a size of about 100 to 300 탆 are supplied into a fluidized bed reactor filled with metal silicon particles, and trichloro The production of trichlorosilane (the reaction of the formula (3)) and the reaction of the production of the siloxane (reaction of the formula (3)) and the reaction of the production of the trichlorosilane by the reaction of the metal silicon, tetrachlorosilane and hydrogen (See FIG. 1). In the above method, since the size of the metal silicon particles gradually decreases as the reaction progresses, it is necessary to replenish the metal silicon particles. However, since the replenishment timing is determined based on the temperature change of the raw material, the reaction temperature is not constant and fluctuates, resulting in a problem that the quality of the product is uneven depending on the reaction time.

In addition, the conventional process using a fluidized bed reactor (FBR) is a simple solid-gas phase reaction process in which solid metal silicon reacts with liquid tetrachlorosilane, and thus there is a limit to improvement in conversion rate.

Therefore, there is a demand for a method capable of converting chlorosilanes, particularly tetrachlorosilane, into trichlorosilane in the exhaust gas of the process for producing polysilicon from trichlorosilane to be more efficiently reused.

Japanese Patent No. 3324922 Japanese Patent Laid-Open No. 56-73617

An object of the present invention is to provide a method for efficiently converting chlorosilanes, especially tetrachlorosilane, into trichlorosilane in the exhaust gas in the step of producing polysilicon from trichlorosilane.

Also, an apparatus for producing trichlorosilane capable of implementing the above method is provided.

According to an aspect of the present invention,

In a tubular reactor passing alternately between a low temperature zone and a high temperature zone,

There is provided a process for producing trichlorosilane, which comprises reacting a mixture of metal silicon particles dispersed in a liquid silane compound containing tetrachlorosilane together with hydrogen or hydrogen and hydrogen chloride to produce trichlorosilane .

The tetrachlorosilane reacts in a liquid state in the low-temperature region, and the tetrachlorosilane reacts in a gaseous state in the high-temperature region.

The low-temperature region reaction can be carried out at a pressure of not less than 100 ° C and not more than 320 ° C and not less than 10 bar and not more than 550 bar.

The high temperature region reaction can be carried out at a temperature of 300 ° C or more and 600 ° C or less, and a pressure of 10 bar or more and 550 bar or less.

The metal silicon particles preferably have a weight average particle diameter of about 35 microns or less.

The weight ratio of the metal silicon particles to the liquid silane compound may be about 1:20 to about 1: 200.

The liquid silane compound may be a by-product of the polysilicon precipitation process by thermal decomposition of trichlorosilane.

The reaction may be carried out at a weight ratio of hydrogen to tetrachlorosilane of 1:20 to 1: 200.

The reaction may also be carried out at a weight ratio of hydrogen chloride to tetrachlorosilane of 1: 0 to 1: 10.

According to one embodiment, it may further comprise separating the silicon particles remaining in the product after the reaction.

According to another embodiment, the metal silicon particles may be depleted in the reaction so that they do not remain in the product after the reaction.

Can be used in the step of pyrolysis of trichlorosilane produced according to the above-mentioned method to precipitate polysilicon.

The present invention also provides a method of manufacturing a semiconductor device,

Silane-based compound supply means comprising liquid tetrachlorosilane;

Optionally, hydrogen chloride supply means;

An apparatus for mixing a silane-based compound supplied from each of the supply means with hydrogen chloride to form a liquid mixture;

Metal silicon particle supplying means for supplying and dispersing metal silicon particles to the liquid mixture;

A tubular reactor supplied with a mixture of dispersed metal silicon particles and designed to alternate between a low-temperature region and a high-temperature region;

Hydrogen gas supply means for supplying hydrogen gas to the reactor; And

And means for recovering trichlorosilane from the product discharged from the tubular reactor.

According to one embodiment, the metal silicon particles may be supplied in a dispersed state in a liquid silane compound.

In addition, the apparatus may further comprise a raw material storage tank equipped with a stirrer for storing a mixed solution in which metal silicon particles are dispersed.

According to one embodiment, the linear velocity at which the mixed solution in which the metal silicon particles are dispersed is supplied to the tubular reactor may be adjusted to such an extent that precipitation of the metal silicon particles does not occur.

According to the present invention, in a continuous process using a tubular reactor, the reaction temperature and the pressure are adjusted to phase-change the tetrachlorosilane to the liquid phase or the gas phase, thereby enabling both the liquid-solid region or the gas- The productivity of trichlorosilane can be improved. In addition, since a micro-tubular reactor is used instead of a fluidized bed reactor, heat control is facilitated, so that side reactions can be minimized and product quality and productivity can be improved.

1 is a schematic view of a fluidized bed process according to the prior art.
2 is a graph showing the relationship between boiling point and vapor pressure of tetrachlorosilane (STC) and trichlorosilane (TCS).
3 schematically illustrates the reaction principle of metal silicon particles and tetrachlorosilane in the low temperature region and the high temperature region.
4 is a schematic flow chart of a process for producing trichlorosilane according to the present invention.
FIG. 5 schematically shows the reaction in the low-temperature region and the high-temperature region of the tubular reactor shown in FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a process for producing a trichloro compound by injecting a mixture in which a metal silicon particle is dispersed in a liquid silane compound containing tetrachlorosilane together with hydrogen or hydrogen and hydrogen chloride in a tubular reactor alternately passing through a low temperature region and a high temperature region, To produce a siloxane of formula < RTI ID = 0.0 > (I) < / RTI >

In other words, the present invention is a system in which the phase transition (liquid-gas) of the liquid raw material is generated by dividing the temperature region into the low-temperature region and the high-temperature region in the continuous process tubular reactor.

Figure 2 representatively shows the relationship between the boiling point and the vapor pressure of tetrachlorosilane (STC) and trichlorosilane (TCS). As can be seen from FIG. 2, it can be seen that the liquid phase reaction material containing tetrachlorosilane can be changed over by appropriately adjusting the reaction temperature and pressure. For example, assuming that the internal pressure of the reactor is 200 bar, when the temperature is lower than 400 ° C, the tetrachlorosilane (STC) becomes a liquid and the silicon powder can be transferred. On the contrary, when the temperature is higher than 400 ° C, tetrachlorosilane becomes a gas, so tetrachlorosilane which is wetted on the surface of the silicon powder is vaporized, so that the silicon powder becomes surface contact with hydrogen chloride gas or hydrogen gas, so that the reactivity of the silicon powder becomes high.

The reaction raw material is a mixture of solid (metal silicon particles), liquid (tetrachlorosilane-containing silane compound), gas (hydrogen or hydrogen chloride) And serves as a fluid conveyance.

The conversion reaction according to the present invention can be carried out as follows.

3SiCl ₄ (l) + 2H ₂ (g) + Si (s) -> 4SiHCl ₃ (l) + H ₂ (g) + HCl (g)

Fig. 3 schematically shows the reaction principle in the low-temperature region and the high-temperature region.

First, in the low-temperature region, the liquid raw material is transferred to the surface of the solid raw material in a wet state, and the product, trichlorosilane, is present in the liquid phase and can be fed at the same time.

According to the present invention, since the entire system is a continuous tubular reactor, the reaction must be continuously carried out while the reaction is being carried out. If all of the reactants are in the form of gas and solid (silicon powder), it is impossible to transfer between the gas and the solid. Therefore, in order to transfer the solid silicon powder, tetrachlorosilane having a relatively low vapor pressure in the gas is liquefied to transfer the silicon powder . That is, the liquid phase tetrachlorosilane in the low temperature region and the tetrachlorosilane in the gaseous phase in the high temperature region completely change the role in the tubular reactor.

After being transferred to the high temperature region, tetrachlorosilane (STC) wetted with the metal silicon particles is vaporized to react with other reaction gases (hydrogen or hydrogen chloride) on the metal silicon particles.

The low-temperature region should be at least 100 ° C and the high-temperature region should be at most 600 ° C. If the temperature difference between the high-temperature region and the low-temperature region is too large, the temperature boundary between the two regions widens, and the effect of each region may be deteriorated. The low-temperature region and the high-temperature region may vary depending on the reaction pressure inside the reaction tube. For example, if the pressure inside the reaction tube is 50 bar, the low-temperature region is at least 100 ° C and less than 220 ° C, and the high-temperature region is at least 260 ° C and less than 600 ° C. If the pressure inside the reaction tube is 100 bar, the low temperature region is at least 100 ° C and less than 270 ° C, and the high temperature region is at least 320 ° C and less than 600 ° C. If the pressure inside the reaction tube is 150 bar, the temperature range is from 100 ° C to less than 320 ° C, and the high temperature range is from 370 ° C to less than 600 ° C.

The region of the reaction temperature with more detailed pressure depends on the vapor pressure curve of the tetrachlorosilane and trichlorosilane of FIG. The low-temperature region follows the vapor pressure curve of trichlorosilane, in which both the reactant tetrachlorosilane and the product trichlorosilane can become liquids, and the high temperature region follows the vapor pressure curve of tetrachlorosilane with a relatively low vapor pressure.

The gas-liquid-solid three-phase reaction is difficult because the contact site of the solid surface is blocked by the liquid. By regulating the reaction conditions, the liquid is vaporized and the solid-gas reaction is induced to increase the reaction efficiency .

Hereinafter, each reactant will be described in more detail.

Tetrachlorosilane

The tetrachlorosilane used in the reaction according to the present invention is not particularly limited, but in order to make effective use of tetrachlorosilane as a by-product in the production process of polysilicon and the like, tetrachlorosilane produced as a by- Silane can be used.

Metal silicon particles

By controlling the size of the metal silicon particles to 35 microns or less, the contact area between tetrachlorosilane and silicon particles is increased and the reaction sites are increased, so that the reaction rate is increased and the productivity of trichlorosilane can be increased. Since the size of the metal silicon particles gradually decreases, the silicon particles may be completely exhausted after a certain reaction time.

In the present invention, metal silicon particle particles are used to uniformly disperse silicon metal particles in liquid tetrachlorosilane to prevent aggregation and precipitation, and to increase the contact area between silicon metal particles and tetrachlorosilane.

The metal silicon used in the above reaction is a solid particle material containing a metal element silicon such as metal silicon, iron silicon, or polysilicon, which is a metallurgical agent. There are no particular restrictions on the content or content of impurities such as iron compounds contained in the metal silicon. However, in the present invention, the metal silicon particles or powder are referred to as particles having a weight average particle diameter of about 35 microns or less. The average particle size of the metal silicon may be about 30 microns or less, or about 25 microns or less, or about 10 microns or less, or about 5 microns or less, about 0.1 microns or more, or about 0.5 microns or more.

The mixing ratio of metal silicon particles to tetrachlorosilane may be about 200 parts by weight or less, about 150 parts by weight or less, about 20 parts by weight or about 50 parts by weight or more, based on 1 part by weight of the metal silicon particles.

The amount of the metal silicon particles to be injected can be appropriately selected within a range such that the distance between the metal silicon particles dispersed in tetrachlorosilane is about 1000 nm or less, about 500 nm or less, about 10 nm or more, or about 50 nm or more.

Preferably, the step of separating the metal silicon of the fine particles used in the reaction and separating the remaining metal silicon from the reaction product can be omitted by preventing the metal silicon particles from being used and remaining in the reaction.

Hydrogen

Hydrogen in the reaction according to the invention helps to react with tetrachlorosilane to form trichlorosilane. As the source of hydrogen, various industrially available hydrogen may be used, and hydrogen or the like discharged during the production of polysilicon may be appropriately purified and used.

The weight ratio of hydrogen to tetrachlorosilane can be 1:20 to 200, preferably 1:50 to 100.

Alternatively, it may be in the range of 5 moles or less of hydrogen, 4 moles or less, or 3 moles or less based on 1 mole of tetrachlorosilane, and may be 1 mole or more, but the present invention is not limited thereto. It can be set in an appropriate range depending on the type and size of the reaction apparatus.

Hydrogen chloride

Hydrogen chloride used in the reaction with the metal silicon can be selectively added, and even if hydrogen or the like is mixed, it is used without any limitation. However, in general, chlorosilanes such as trichlorosilane, tetrachlorosilane, and dichlorosilane react with moisture because of high hydrolysis ability. Therefore, if water is contained in the hydrogen chloride, the yield of the produced trichlorosilane may be lowered. Therefore, it is preferable that the hydrogen chloride is in a dry state. Since the hydrogen chloride is dispersed in the molecular unit, it can be sufficiently distributed around the silicon nanoparticles dispersed in the liquid reaction product, thereby increasing the reaction efficiency.

The weight ratio of hydrogen chloride and tetrachlorosilane may be 1: 0 to 10 or less, preferably 1: 0 to 5 or less.

Or about 1 mole or less, or about 0.8 mole or less, or about 0.5 mole or less, relative to 1 mole of tetrachlorosilane, and more preferably about 0.1 mole or more, or about 0.2 mole or more, Speed, and can be set in an appropriate range depending on the type and size of the reaction apparatus.

Reactor

Since the reaction according to the present invention proceeds in a liquid phase, it is preferable to use a tubular reactor, particularly a microtubular reactor, as the reactor. The microtubular reactors are preferred for ensuring a uniform dispersion of the reactants and a sufficient residence time that the tubular inner diameter is in the range of about 10 mm or less or about 1 mm or more and the length is about 10 cm or more or about 500 cm or less . The ratio of diameter to length of the microtubular reactor may be from 1:10 to 5000, more preferably from 1:20 to 500.

The reaction temperature may be suitably determined in consideration of the material and the capability of the production apparatus. However, if the reaction temperature is higher than necessary, the selectivity of trichlorosilane is lowered and chlorosilane other than trichlorosilane such as tetrachlorosilane or dichlorosilane The amount of silane byproduct is increased. Direct chlorination (Si + 3HCl → SiHCl ₃ + H ₂ ) is an exothermic reaction. The reaction in which tetrachlorosilane reacts with hydrogen in the same reactor to form trichlorosilane is an endothermic reaction. Therefore, the reaction temperature can be set variously considering the conditions of these two reactions.

Particularly, in the present invention, since it is necessary to induce the phase change of the liquid reaction material, it is important that the tubular reactor alternately pass the high temperature region and the low temperature region.

The low temperature region is generally set to a range of 320 DEG C or less. Preferably 300 DEG C or lower, and may be set to a temperature of 100 DEG C or higher, or 150 DEG C or higher, but is not limited thereto. As the pressure of the reactor increases, the selectivity of trichlorosilane increases and the reactivity of tetrachlorosilane also increases. It is set at a pressure of about 10 bar or more, or about 550 bar or less.

The STC should be in the vapor phase and the reaction condition should be below the STC vapor pressure because the STC should be in the vapor phase. . If the STC is in a liquid state, the surface of the silicon powder is in a wet state, and hydrogen chloride can not react with the silicon surface. Therefore, all STC in liquid state should be vaporized.

Since the apparatus according to the present invention is a continuous tubular reactor, the pressures in the high-temperature region and the low-temperature region become equal unless a special pressure control apparatus (for example, a back pressure regulator) is separately installed. Therefore, STC can be divided into a low-temperature region (liquid phase) and a high-temperature region (gaseous phase) depending on the vapor pressure condition of the STC since the only variable capable of phase- For example, when the internal pressure of the tubular reactor is 200 bar, the temperature at which the phase transition of the STC is represented by about 400 ° C., the temperature in the high temperature region may be higher than 400 ° C., and the low temperature region may be 400 ° C. or lower . It is preferable to control the temperature of the high temperature region to 450 deg. C or more, and the temperature of the low temperature region to 350 deg. C or less so that the reaction temperature of the high temperature region and the low temperature region may differ by a predetermined temperature or more. However, if the temperature difference between the two areas is too large, temperature control will be difficult and the durability of the equipment will be affected. Therefore, it is necessary to set the temperature considering all the conditions as well as the reactivity. For example, the reaction temperature in the high temperature range is suitably from about 300 ° C to about 600 ° C, more preferably from about 350 ° C to 500 ° C.

Reaction catalyst

In the process according to the present invention, a catalyst may be used to enhance the reaction efficiency but it is not necessarily used. The present invention enables an efficient reaction without a catalyst.

As the catalyst, any known catalyst component in the reaction of metallic silicon and hydrogen chloride can be used without limitation. Specific examples of such a catalyst component include a metal or a chloride of a Group VIII element such as iron, cobalt, nickel, palladium, and platinum, and a metal or a chloride such as aluminum, copper, or titanium. These catalysts may be used alone or in combination of a plurality of catalysts. The amount of the catalyst component to be used is not particularly limited as far as the trichlorosilane is used in an amount sufficient to improve the production efficiency, and may be suitably determined in consideration of the capability of the production apparatus.

The catalyst component may be present by adding it to the reaction system, but when the metal silicon to be used contains a catalyst component such as an iron compound as an impurity, this impurity can be effectively used as a catalyst component. Needless to say, even when metal silicon containing a catalyst component as an impurity is used, there is no problem even if a catalyst component is further added into the reaction system in order to enhance reactivity between metal silicon and hydrogen chloride.

Polysilicon manufacturing

The trichlorosilane prepared from tetrachlorosilane according to the present invention can be used as a raw material for producing a high-purity polycrystalline silicon (aka polysilicon). As shown in the following reaction formula, trichlorosilane is pyrolyzed at a high temperature of 1000 占 폚 or higher and precipitated as polysilicon. In some cases, it may be desirable to pyrolyze in the presence of hydrogen.

₄ SiHCl ₃ ? Si + ₃ SiCl ₄ + 2H ₂ (1)

SiHCl ₃ + H ₂ ? Si + 3HCl (2)

Polysilicon precipitation reaction using trichlorosilane is well known in the art, and therefore, description of specific process conditions is omitted.

The apparatus for producing trichlorosilane according to the present invention comprises

Silane-based compound supply means comprising liquid tetrachlorosilane;

Optionally, hydrogen chloride supply means;

An apparatus for mixing a silane-based compound supplied from each of the supply means with hydrogen chloride to form a liquid mixture;

Metal silicon particle supplying means for supplying and dispersing metal silicon particles to the liquid mixture;

A tubular reactor supplied with a mixture of dispersed metal silicon particles and designed to alternate between a high temperature region and a low temperature region;

Hydrogen gas supply means for supplying hydrogen gas to the reactor; And

And means for recovering trichlorosilane from the product discharged from the tubular reactor.

More specifically, in the hydrogen gas supply means, the hydrogen gas flow rate can be controlled by an MFC (Mass Flow Controller). The hydrogen gas discharged by the pressure of the hydrogen raw material bottle is supplied to the reactor after the flow rate is controlled through the MFC.

In the hydrogen chloride supplying means, the hydrogen chloride gas can be controlled by the MFC. The hydrogen chloride gas discharged by the pressure of the hydrogen chloride bomb is dissolved in the tetrachlorosilane solution and supplied to the reactor together with the tetrachlorosilane solution.

According to one embodiment, the tetrachlorosilane solution in which the hydrogen chloride is dissolved can be stored in the raw material storage tank.

The raw material storage tank is preferably made of a double jacket so as to maintain a temperature of 10 ° C or less in consideration of the boiling point of the raw material, so that the low temperature is maintained by the cooler.

A device capable of adding silicon powder is mounted on the upper part of the tank, and silicon powder can be injected and dispersed in the tetrachlorosilane solution.

The tank may be provided with a space for preventing external air from entering into the container, and the space of the space is connected to a vacuum pump to prevent the inflow of external oxygen and moisture when the silicon powder is injected.

In order to maintain the uniform dispersion state of the silicon particles, it is preferable that the raw material storage tank is equipped with a stirrer. The stirrer rotates from about 50 rpm to about 500 rpm and inhibits precipitation of silicon particles.

There may be two or more of these raw material storage tanks, and when the raw materials stored in the first tank are exhausted, the pipes are connected so that they can be continuously injected in the second tank.

The mixture in which the silicon particles are dispersed is continuously injected into the tubular reactor from the raw material storage tank by the liquid transfer pump. The liquid transfer pump may have a discharge pressure of about 100 bar or more, more preferably about 200 bar or more. Solid silicon powder should also be transported with the solution, and a specific type of pump (high pressure pump) is suitable considering the reactivity of the tetrachlorosilane solution with water and oxygen.

The raw material injected into the tubular reactor using the high pressure pump is reacted through the tubular reactor passing alternately through the low temperature region and the high temperature region. In this case, the reaction temperature in the low-temperature region is suitably selected from the range of about 100 ° C to about 320 ° C, and more preferably about 150 ° C to 300 ° C. The reaction temperature in the high temperature region is suitably selected in the range of about 300 캜 to about 600 캜, and more preferably about 350 캜 to 500 캜.

After completion of the reaction, the product is cooled to not more than 10 캜 of the tubular reactor, and then, the product is in a liquid state and recovered to the collecting device. At this time, the unreacted hydrogen, hydrogen chloride gas and chlorine gas are separated from the liquid by the collecting device, and the liquid is transferred to another storage container through another transfer device.

Hereinafter, an embodiment according to the method of the present invention will be described in more detail with reference to the drawings.

Figures 4 and 5 schematically illustrate an apparatus according to one embodiment of the present invention.

As shown in FIG. 4, the gaseous tetrachlorosilane (1) passes through the cooler (10) and is converted into liquid tetrachlorosilane (2). Liquid tetrachlorosilane (2) is combined with hydrogen chloride (4), and hydrogen chloride is dissolved in tetrachlorosilane to form a liquid phase. And the metal silicon particles 6 are added to the mixture. But may be pressurized by pump 20 as needed before it is combined with the metal silicon particles.

The hydrogen gas may be added to any of the steps described above. For example, the liquid tetrachlorosilane (2) may be added before or after compounding with hydrogen chloride (4), or before or after dispersing the metal silicon particles.

The liquid tetrachlorosilane / hydrogen chloride mixed solution 7 in which the metal silicon particles are dispersed is injected into the tubular reactor 30 and the reaction proceeds. Although not shown in the figure, the mixed liquid may be stored in a raw material storage tank equipped with a stirrer as described above. The reactor 30 is provided with heating means (not shown) for providing an optimum reaction temperature and can be designed to provide sufficient residence time and contact area.

As shown in Fig. 5, the tubular reactor is designed to alternate between the low-temperature region and the high-temperature region.

The liquid metal raw material (solid), tetrachlorosilane (liquid or gas), hydrogen (gas) and hydrogen chloride (gas) injected as a reaction raw material are solid-liquid-gas mixtures, The silicon particles are impregnated and transferred to the high temperature region. In the high temperature region, the solid phase-gas phase reaction can proceed while the liquid reaction material wetted on the surface of the metal silicon particles is vaporized. Thereafter, the liquid reaction material is again wetted to the solid phase reaction raw material while being moved to the low temperature region, and the reaction is carried out again to the high temperature region. By repeating this process, the conversion efficiency can be increased.

Further, the silicon particles dispersed in tetrachlorosilane precipitate because of high density. Therefore, the linear velocity at which the silicon-dispersed silane solution passes through the tubular reactor should be higher than the deposition rate of silicon. For example, in the case of 10 μm silicon particles, the settling rate in a tetrachlorosilane solution is about 10 mm per second. To pass the solution through a tubular reactor with an inner diameter of 10 mm without precipitation, the linear velocity of the solution is at least 10 mm Or more. Therefore, the length and the inner diameter of the tubular reactor can be determined according to the size of the silicon powder and the settling velocity.

According to a preferred embodiment, the metal silicon particle particles can be exhausted to the reaction, in which case a process (for example a filtering process) for separating the remaining metallic silicon particles after the reaction can be omitted.

The effluent 8 from the reactor 3 is present in a liquid state by the pressure in the reactor and a pressurized or reduced pressure distillation apparatus can be used to separate the trichlorosilane and hydrogen chloride / hydrogen in the liquid reaction product. However, Liquid trichlorosilane can be easily obtained by using trichlorosilane, hydrogen chloride, and hydrogen, which are present in a liquid state immediately after the reaction, in a state in which the silane is a liquid and hydrogen chloride and hydrogen are gases.

The process according to the present invention proceeds in a liquid phase reaction using a tubular reactor using liquid tetrachlorosilane and reacts with metallic silicon particles, so that reactants can be uniformly mixed, the reaction surface area is increased, and the reaction temperature is easily controlled So that the production efficiency can be maximized.

Hereinafter, a specific embodiment of the present invention will be described. However, the following examples are only illustrative of the present invention, and the scope of the present invention is not limited thereto.

Example 1

A microtubular reaction tube with four SUS316 reaction tubes having an inner diameter of 4 mm and a length of 300 mm was heated at a reaction temperature of 350 ° C and an internal pressure of 160 bar, 3 mu m) was dispersed in tetrachlorosilane at 1 wt%, hydrogen chloride, and hydrogen were introduced at the flow rates shown in Table 1, respectively. The temperature of the low temperature region and the high temperature region and the pressure inside the reaction tube were as follows.

Low temperature region: 260 DEG C, 100 bar

High temperature zone: 360 ° C, 100 bar

Example 2

The low-temperature zone reaction temperature was 210 ° C. The reaction was carried out in the same manner as in Example 1-1 except that the reaction temperature in the high temperature region was set to 300 ° C and the pressure in the reaction tube was set to 80 bar to make the STC liquid phase even in the high temperature region. Mol%.

Comparative Example 1

The reaction was carried out in the same manner as in Example 1-1, except that the reaction temperature in the low-temperature region was 320 ° C. and the reaction temperature in the high-temperature region was 400 ° C., and the pressure inside the reaction tube was 60 bar, The TCS content of the resultant was 7 mol%, but the reaction product, silicon, was entrained in the tubular reactor and the continuous process was impossible.

10. Cooler
20. Pump
30. Tubular Reactor

Claims (16)

In a tubular reactor passing alternately between a low temperature zone and a high temperature zone,
Characterized in that trichlorosilane is produced by reacting a mixture of metal silicon particles dispersed in a liquid silane compound containing tetrachlorosilane with hydrogen or hydrogen and hydrogen chloride. The method according to claim 1,
Wherein the tetrachlorosilane reacts in a liquid state in the low-temperature region, and the tetrachlorosilane reacts in a gaseous state in the high-temperature region, The method according to claim 1,
Wherein the low-temperature region reaction is carried out at a temperature of 100 ° C or more and 320 ° C or less, and a pressure of 10 bar or more and 550 bar or less. The method according to claim 1,
Wherein the high-temperature region reaction is carried out at a temperature of not less than 300 DEG C and not more than 600 DEG C, and a pressure of not less than 10 bar and not more than 550 bar. The method according to claim 1,
Wherein the metal silicon particles have a weight average particle size of 35 microns or less. The method according to claim 1,
Wherein the weight ratio of the metal silicon particles to the liquid silane compound is from 1:20 to 1: 200. The method according to claim 1,
Wherein said liquid silane compound is a by-product of a polysilicon precipitation process by thermal decomposition of trichlorosilane. The method according to claim 1,
Wherein the weight ratio of hydrogen to tetrachlorosilane is from 1:20 to 200. The method according to claim 1,
Wherein the weight ratio of hydrogen chloride to tetrachlorosilane is 1: 0 to 10. The method according to claim 1,
Further comprising separating the silicon particles remaining in the product after the reaction. The method according to claim 1,
Wherein the metal silicon particles are consumed in the reaction and do not remain in the product after the reaction. A process for producing polysilicon, comprising the step of pyrolyzing trichlorosilane produced by any one of claims 1 to 11 to precipitate polysilicon. Silane-based compound supply means comprising liquid tetrachlorosilane;
Optionally, hydrogen chloride supply means;
An apparatus for mixing a silane-based compound supplied from each of the supply means with hydrogen chloride to form a liquid mixture;
Metal silicon particle supplying means for supplying and dispersing metal silicon particles to the liquid mixture;
A tubular reactor supplied with a mixture of dispersed metal silicon particles and designed to pass alternately through the low temperature region and the high temperature region;
Hydrogen gas supply means for supplying hydrogen gas to the reactor; And
And means for recovering trichlorosilane from the product discharged from said tubular reactor. 14. The method of claim 13,
Wherein the metal silicon particles are supplied in a form dispersed in a liquid silane compound. 14. The method of claim 13,
And a raw material storage tank equipped with an agitator for storing a mixed solution in which the metal silicon particles are dispersed. 14. The method of claim 13,
Wherein the linear velocity at which the mixed solution in which the metal silicon particles are dispersed is supplied to the tubular reactor is adjusted to a range that does not cause precipitation of the metal silicon particles.

Images