JPWO2010116500A1 - Trichlorosilane cooling tower and method for producing trichlorosilane using the same - Google Patents

Abstract

The present invention relates to a trichlorosilane cooling tower capable of reducing the amount of high-boiling point polymer contained in a reaction product gas after cooling without reducing the recovery rate of trichlorosilane, and a raw material containing tetrachlorosilane and hydrogen A spraying means for spraying a cooling liquid to a reaction product gas containing trichlorosilane obtained by reacting a gas at a temperature in the range of 700 to 1400 ° C. to cool it to a temperature range of 70 to 600 ° C., and a reaction after cooling Injection means for bringing hydrogen chloride gas into contact with the product gas.

Description

  The present invention relates to a trichlorosilane cooling tower used when producing trichlorosilane from tetrachlorosilane and hydrogen, and a method for producing trichlorosilane using the trichlorosilane cooling tower.

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 bringing vaporized tetrachlorosilane (SiCl ₄ ) and hydrogen (H ₂ ) into contact in a reaction furnace 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 in a reaction furnace to 700 to 1400 ° C.

  Since the reaction of trichlorosilane produced from tetrachlorosilane and hydrogen is an endothermic reaction, according to Le Chatelier's principle, cooling the reaction product gas will counteract the temperature drop due to cooling, that is, trichlorosilane and chloride. The equilibrium is tilted in the direction of producing tetrachlorosilane from hydrogen.

  Therefore, in order to efficiently recover trichlorosilane, as shown in Patent Document 1, after reaching the thermal equilibrium state of the above formula (1), the reaction is performed so that once generated trichlorosilane does not return to tetrachlorosilane again. It is necessary to cool the product gas to a predetermined temperature as quickly as possible to freeze the equilibrium. In order to instantly freeze the equilibrium state, Patent Document 1 describes that the reaction product gas is rapidly cooled to 300 ° C. or less in less than 1 second.

However, when the reaction product gas is rapidly cooled, high-boiling polymers such as Si ₂ Cl ₆ , Si ₃ Cl ₈ , and Si ₂ H ₂ Cl ₄ are liable to be by-produced. Since these high-boiling-point polymers may adhere to the wall of the pipe in the plant and block the pipe and hinder continuous operation of the plant, it is preferable to suppress the generation thereof.

  In the method described in Patent Document 1, a reaction product gas is led out from a high-temperature reactor to a cooling tower, where a coolant is directly sprayed on the reaction product gas, and reaction is performed using latent heat of vaporization when the coolant is vaporized. It has excellent cooling efficiency in that it takes heat away from the product gas. However, Patent Document 1 does not specifically disclose a means for suppressing the formation of a high-boiling polymer that accompanies rapid cooling.

In the method described in Patent Document 1, the produced trichlorosilane is mainly condensed in the quenching chamber and collected in a receiver provided below the quenching chamber. Therefore, a large amount of high boiling point polymers such as Si ₂ Cl ₆ , Si ₃ Cl ₈ , and Si ₂ H ₂ Cl _{4 having} a higher boiling point are mixed in the acceptor together with trichlorosilane, and from the recovered chlorosilane mixture, The load for the work of fractionating only the target trichlorosilane is increased.

Japanese Patent Publication No.57-38524

  The present invention has been made in view of the above circumstances, and a trichlorosilane cooling tower capable of suppressing by-product formation of a high boiling point polymer without reducing the recovery rate of trichlorosilane and a method for producing trichlorosilane using the same. The purpose is to provide.

The present invention employs the following configuration in order to solve the above problems.
That is, the trichlorosilane cooling tower of the present invention is
A coolant is sprayed on a reaction product gas containing trichlorosilane obtained by reacting a raw material gas containing tetrachlorosilane and hydrogen at a temperature in the range of 700 to 1400 ° C., and cooled to a temperature range of 70 to 600 ° C. Spraying means to
Injection means for bringing hydrogen chloride gas into contact with the reaction product gas after cooling;
Have

In addition, the method for producing trichlorosilane of the present invention includes:
A coolant is sprayed on a reaction product gas containing trichlorosilane obtained by reacting a raw material gas containing tetrachlorosilane and hydrogen at a temperature in the range of 700 to 1400 ° C., and cooled to a temperature range of 70 to 600 ° C. And a process of
A step of bringing hydrogen chloride gas into contact with the reaction product gas after cooling;
Have

<Reduction of high boiling point polymer and improvement of trichlorosilane recovery>
As a result of intensive studies, the inventors of the present invention have reduced the recovery rate of trichlorosilane by spraying a cooling liquid on the reaction product gas and freezing the equilibrium, and then bringing hydrogen chloride gas into contact with the reaction product gas after cooling. The present inventors have found that the amount of high-boiling point polymer produced as a by-product can be reduced.

  By directly spraying the coolant on the reaction product gas, heat can be efficiently and instantly removed from the reaction product gas using latent heat of vaporization when the coolant is vaporized. Therefore, the equilibrium can be instantly and efficiently frozen, and loss of trichlorosilane due to the generated trichlorosilane returning to tetrachlorosilane can be reduced.

On the other hand, with the rapid cooling of the reaction product gas, a large amount of high boiling point polymer is also produced as a by-product. By bringing hydrogen chloride gas into contact with the reaction product gas after equilibrium freezing, the following reaction formula (2 ) To (4) can decompose the high-boiling point polymer and, at the same time, derive trichlorosilane from the high-boiling point polymer.
Si ₂ Cl ₆ + HCl → SiHCl ₃ + SiCl ₄ (2)
Si ₃ Cl ₈ + 2HCl → 2SiHCl ₃ + SiCl ₄ (3)
Si ₂ H ₂ Cl ₄ + 2HCl → 2SiHCl ₃ (4)
The decomposition reaction can be sufficiently carried out even in the temperature range of the reaction product gas immediately after freezing the equilibrium. Moreover, since hydrogen chloride gas is injected into the reaction product gas after freezing the equilibrium, the balance of the above formula (1) is inclined to the tetrachlorosilane side due to the presence of a large amount of hydrogen chloride, and the loss of trichlorosilane is reduced. There will be no increase.

  Thus, according to the trichlorosilane cooling tower and the trichlorosilane production method using the same according to the present invention, the amount of the high boiling point polymer contained in the reaction product gas after cooling is reduced without reducing the recovery rate of trichlorosilane. Can be reduced. Therefore, the productivity of trichlorosilane can be greatly improved, the operation efficiency of the plant can be increased, and continuous operation can be performed.

It is explanatory drawing of the apparatus for implementing the trichlorosilane cooling tower which is one Embodiment of this invention, and the trichlorosilane manufacturing method using the same.

100 Trichlorosilane cooling tower 101 Metal container 102 Primary spray nozzle 103 Secondary spray nozzle 104 Primary coolant supply pipe 105 Secondary coolant supply pipe 106 Quench pipe 107 Filling member 108 Reaction product gas introduction opening 109 Cooling tower gas component exhausted Outlet pipe 110 Cooling tower liquid component extraction pipe 111 Inlet opening 112 Outlet opening 113 Hydrogen chloride gas injection nozzle 114 Hydrogen chloride gas supply pipe 200 Raw material gas supply pipe 201 Reactor 202 Heater 203 Reactor gas extraction pipe 300 Condenser 301 Storage Tank 400 Circulating Fluid Tank 401 Prepared Solution Supply Pipe 402 Pump 403 Heat Exchanger

<Explanation of terms>
In this specification, “primary cooling” refers to cooling intended to freeze the equilibrium reaction of the above formula (1) by instantaneously reducing the temperature of the reaction product gas to a temperature range of 70 to 600 ° C.
In the present specification, “secondary cooling” refers to auxiliary cooling for the purpose of further reducing the temperature of the reaction product gas after the primary cooling as necessary.
Although the temperature of the reaction product gas can be reduced by bringing the hydrogen chloride gas into contact with the reaction product gas after the primary cooling, the main purpose of bringing the hydrogen chloride gas into contact with the reaction product gas in the present invention is the high boiling point polymer. In the following, because of the decomposition, cooling of the reaction product gas caused by contact with hydrogen chloride gas is not included in the concept of “secondary cooling”.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1. Trichlorosilane Cooling Tower FIG. 1 schematically shows an apparatus for carrying out a trichlorosilane cooling tower of this embodiment and a method for producing trichlorosilane using the same.
The trichlorosilane cooling tower 100 of the present embodiment includes a substantially cylindrical metal container 101, a primary spray nozzle 102 and a secondary spray nozzle 103 that are means for spraying a cooling liquid into the metal container 101, and the primary spray. Rapid cooling provided to accommodate the primary spray nozzle 102 inside the metal container 101 and the primary coolant supply pipe 104 and the secondary coolant supply pipe 105 that supply the coolant to the nozzle 102 and the secondary spray nozzle 103, respectively. A pipe 106, a filling member 107 installed between the primary spray nozzle 102 and the secondary spray nozzle 103, a hydrogen chloride gas injection nozzle 113 for injecting hydrogen chloride gas into the metal container 101, and the hydrogen chloride gas A hydrogen chloride gas supply pipe 114 for supplying hydrogen chloride gas to the injection nozzle 113 is provided.

<Metal container>
The metal container 101 is not particularly limited as long as it is a material that does not react with the reaction product gas, and can typically be made of a metal such as stainless steel. A reaction product gas introduction opening 108 for taking in the reaction product gas is provided on the side wall of the metal container 101. A cooling tower gas component extraction pipe 109 for extracting a gas component of the cooled reaction product gas is connected to the top of the metal container 101, and the bottom of the metal container 101 was used for cooling. A cooling tower liquid component extraction pipe 110 is connected to extract the cooling liquid and the condensed liquid component generated by cooling.

<Quenching tube>
The quenching tube 106 is not particularly limited as long as it does not react with the reaction product gas, and can typically be composed of a metal such as stainless steel.
The quench pipe 106 is provided with an introduction opening 111 for taking in the reaction product gas at a position corresponding to the reaction product gas introduction opening 108 of the metal container 101. Further, the bottom of the quench pipe 106 is open on the entire surface, and a discharge opening 112 for discharging the cooled reaction product gas is formed.

<Cooling liquid spraying means>
In this embodiment, a two-stage cooling liquid spraying means including a primary spray nozzle 102 and a secondary spray nozzle 103 is employed as a means for spraying the cooling liquid into the metal container 101. By providing the cooling liquid spraying means in multiple stages, the primary cooling by the primary spray nozzle 102 rapidly quenches the reaction product gas to a temperature sufficient to freeze the equilibrium, and the secondary cooling by the secondary spray nozzle 103 Cooling according to the purpose can be realized such that the reaction product gas is gently cooled exclusively to condense the high-boiling point polymer. By setting the purpose of primary cooling to equilibrium freezing, it is possible to avoid excessive cooling enough to condense to trichlorosilane in addition to the high-boiling point polymer, and the trichlorosilane together with the high-boiling point polymer and the cooling liquid of the trichlorosilane cooling tower 100 It can prevent flowing down to the bottom side. Further, by secondary cooling of the reaction product gas after the equilibrium freezing, the high boiling point polymer in the reaction product gas is condensed and allowed to flow down to the bottom side of the trichlorosilane cooling tower 100 together with the cooling liquid. The amount of the high boiling point polymer contained in the gas component taken out from the top of the can be reduced.
Of course, as long as the equilibrium of the reaction product gas can be frozen by the coolant spraying means, the coolant spraying means may consist only of primary cooling.

<Primary spray nozzle>
The primary spray nozzle 102 is installed from the canopy portion of the quench pipe 106 toward the inside of the quench pipe 106, and is connected to the primary coolant supply pipe 104. The primary spray nozzle 102 sprays the cooling liquid toward the reaction product gas introduced from the introduction opening 111 of the quench pipe 106, so that the coolant and the reaction product gas are contained in a narrow space in the quench pipe 106. It is made to contact efficiently and is rapidly cooled to 70 to 600 ° C., more preferably to 500 to 600 ° C. where the equilibrium of the above formula (1) freezes.

  Although various types of nozzles can be used as the primary spray nozzle 102, a full-cone nozzle capable of realizing an even flow distribution over the entire spray region is preferable. In particular, it is preferable that the cooling liquid sprayed from the primary spray nozzle 102 can be sprayed in an average droplet particle diameter range of 2000 μm or less. The average droplet particle size depends not only on the nozzle characteristics but also on the spraying conditions. In this embodiment, the spray amount is 0.1 to 0.3 l / min, the spray pressure is 0.1 to 0.2 MPa, When a mixed liquid composed of tetrachlorosilane and trichlorosilane having a mixing ratio, which will be described later, is used as the cooling liquid, one that can realize an average droplet diameter of 2000 μm or less is preferable.

<Average droplet particle size>
The average droplet particle diameter used here is a value obtained by measuring the ni [particle] particle diameter Di [μm] by a liquid immersion method or a laser method and calculating the Sauter average particle size of the following equation.
Average particle diameter = Σni · Di ³ / Σni · Di ²
(Ni is the number of spray droplets of coolant having particle diameter Di)

<Filling member>
The filling member 107 is arbitrarily installed above the primary spray nozzle 102. The filling member 107 is provided with a gas passage so that the reaction product gas that is primarily cooled in the quench pipe 106 and pushed out from the discharge opening 112 of the quench pipe 106 is disturbed in its straight travel when rising inside the trichlorosilane cooling tower 100. Any form can be used as long as it is formed. For example, it may be a form in which small blocks such as chips or blocks are packed irregularly, or a plurality of plate-like members provided with a large number of holes arranged at intervals.
The filling member 107 is not particularly limited as long as it does not react with the reaction product gas, and can typically be made of a metal such as stainless steel.

<Secondary spray nozzle>
The secondary spray nozzle 103 is arbitrarily installed further above the primary spray nozzle 102 and the filling member 107 and is connected to the secondary coolant supply pipe 105. The secondary spray nozzle 103 is sprayed from the discharge opening 112 of the quench pipe 106 and sprays the coolant toward the reaction product gas that rises inside the trichlorosilane cooling tower 100 and passes through the filling member 107. While condensing the boiling point polymer, the temperature of the reaction product gas is gently cooled to the range of 30-60 ° C. The coolant sprayed from the secondary spray nozzle 103 also has a function of lowering the temperature inside the trichlorosilane cooling tower 100 and preventing the coolant from being vaporized before coming into contact with the reaction product gas.

  The secondary spray nozzle 103 is not particularly limited, and various types of nozzles can be used. In particular, a full-cone nozzle that can achieve a uniform flow distribution over the entire spray region is preferred. The average droplet diameter of the cooling liquid sprayed from the secondary spray nozzle 103 is not particularly limited, but is preferably in the range of 2000 μm or less, as in the case of the primary spray nozzle 102, because the cooling efficiency is excellent.

<Cooling liquid>
As the cooling liquid, a mixed liquid composed of tetrachlorosilane and trichlorosilane is preferably used, and the content of tetrachlorosilane in the mixed liquid is preferably 80 to 100 mol%, more preferably 85 to 95 mol%. By using the cooling liquid having such a specific composition, the reaction can be frozen while the equilibrium of the above formula (1) is sufficiently moved to the right side, and trichlorosilane can be recovered with a high yield.
The temperature of the coolant is preferably adjusted to 50 ° C. or lower. If the temperature of the cooling liquid is adjusted to 50 ° C. or less, the temperature of the reaction product gas can be rapidly cooled in a short time, so that the state of being sufficiently moved to the right side in the above equation (1) is maintained. The equilibrium can be frozen.

<Hydrogen chloride gas injection nozzle>
The hydrogen chloride gas injection nozzle 113 is installed at an arbitrary position where hydrogen chloride gas can be injected toward the reaction product gas cooled by the primary spray nozzle 102 and / or the secondary spray nozzle 103. Connected to the supply pipe 114. Since the high boiling point polymer decomposition reaction of the above formulas (2) to (4) is promoted at an ambient temperature of 500 to 600 ° C., the hydrogen chloride gas injection nozzle 113 is a reaction immediately after the equilibrium is frozen by the primary spray nozzle 102. It is particularly preferable to provide a position where hydrogen chloride gas can be injected toward the product gas. For this reason, in the present embodiment, the hydrogen chloride gas injection nozzle 113 is provided in the vicinity of the discharge opening 112 of the quench pipe 106, whereby the hydrogen chloride gas is efficiently brought into contact with the reaction product gas after the primary cooling and injected. When the hydrogen chloride gas rises inside the trichlorosilane cooling tower 100 and exits to the cooling tower gas component extraction pipe 109, the reaction product gas after the secondary cooling can be contacted.

<Hydrogen chloride gas>
The hydrogen chloride gas supplied to the hydrogen chloride gas injection nozzle 113 needs to have a temperature that does not increase the temperature of the reaction product gas after the primary cooling. Further, when low-temperature hydrogen chloride gas is used, not only the high boiling point polymer is decomposed, but also the effect of cooling the reaction product gas can be obtained.
In the present embodiment, hydrogen chloride generated by the reaction of the above formula (1) is taken out and supplied directly to the hydrogen chloride gas injection nozzle 113 to be used as hydrogen chloride gas. That is, the reaction product gas generated by the above formula (1) is cooled by the condenser 300 described later from the cooling tower gas component extraction pipe 109 together with the generated trichlorosilane, unreacted tetrachlorosilane, hydrogen, etc. It is separated into chlorosilanes having a high boiling point and hydrogen chloride and hydrogen having a low boiling point. Since the hydrogen chloride obtained at this time is cooled to at least normal temperature or less in the condenser, it can be supplied to the hydrogen chloride gas injection nozzle 113 without further cooling.

  In addition, when hydrogen chloride is extracted from the reaction product gas and used, unreacted hydrogen or low-boiling chlorosilanes such as monochlorosilane may be mixed in the hydrogen chloride gas, but the equilibrium of formula (1) Is already frozen, it comes into contact with the reaction product gas as hydrogen chloride gas, so these mixed components do not affect the recovery rate of trichlorosilane. Therefore, it is not always necessary to isolate and purify hydrogen chloride.

2. Next, a method for producing trichlorosilane using the above-described trichlorosilane cooling tower will be described with reference to FIG.
First, a raw material gas in which gasified tetrachlorosilane and hydrogen are mixed is supplied to the bottom of the reaction furnace 201 through a raw material gas supply pipe 200.

  The reaction furnace 201 is made of graphite, and can be maintained in a state in which the interior of the reaction furnace 201 exceeds 700 ° C. and is not higher than 1400 ° C. by heating with a heater 202 provided in the periphery. If the reaction temperature is 700 ° C. or higher, the equilibrium of the above formula (1) is sufficiently tilted to the right, and if it is 1400 ° C. or lower, it is preferable because the phenomenon that metal silicon precipitates and leads to blockage of the apparatus can be suppressed.

  The reaction product gas that has been heated in the reaction furnace 201 and has reached the thermal equilibrium state shown in the above formula (1) moves to the upper side of the reaction furnace 201 and maintains a temperature of 700 ° C. or higher in the reaction gas extraction pipe. 203 is introduced into the trichlorosilane cooling tower 100.

The reactor gas extraction pipe 203 passes through the side wall of the trichlorosilane cooling tower 100 and the side wall of the quench pipe 106 and reaches the inside of the quench pipe 106.
Next, a coolant is sprayed from the primary spray nozzle 102 connected to the primary coolant supply pipe 104 to the reaction product gas introduced into the quenching pipe 106, and instantaneously reaches a range of 70 to 600 ° C. where the equilibrium is frozen. Cool rapidly. At this time, the reaction product gas and the liquid droplets in the form of fine droplets are mixed in the narrow quenching tube 106 so that they are more reliably brought into contact with each other by utilizing the latent heat of vaporization when the cooling liquid evaporates. Heat can be taken from the produced gas instantly and efficiently. Thus, the equilibrium state between the substances in the reaction product gas is frozen.

The reaction product gas primarily cooled in the quench pipe 106 is pushed out from the discharge opening 112 at the bottom of the quench pipe 106. Here, with respect to the reaction product gas, hydrogen chloride gas is injected from the hydrogen chloride gas injection nozzle 113 connected to the hydrogen chloride gas supply pipe 114, and the high boiling point polymer contained in the reaction product gas is decomposed.
Next, the reaction product gas rises in the trichlorosilane cooling tower 100 together with the hydrogen chloride gas, and passes through the filling member 107. Here, the coolant is further sprayed from the secondary spray nozzle 103 connected to the secondary coolant supply pipe 105 to condense the high-boiling point polymer remaining in the reaction product gas, and the temperature of the reaction product gas is set to 30. Cool gently to a range of ~ 60 ° C.

The gas component that is still in a gaseous state even when cooled to the range of 30 to 60 ° C. is extracted from the cooling tower gas component extraction pipe 109 and cooled by the condenser 300, where a large amount of chlorosilane in the gas is obtained. The portion is condensed and collected in the storage tank 301. The chlorosilane collected in the storage tank 301 is further sent to a distillation tower (not shown) and separated into trichlorosilane and unreacted tetrachlorosilane.
The hydrogen chloride taken out from the condenser 300 as an uncondensed portion remains in the form of a mixture with other low-boiling substances such as hydrogen, or after isolation and purification, the hydrogen chloride is passed through the hydrogen chloride gas supply pipe 114 as hydrogen chloride gas. And supplied to the hydrogen chloride gas injection nozzle 113.

  On the other hand, a condensed liquid component such as a high boiling point polymer that condenses in the temperature range of 30 to 60 ° C. flows down to the bottom of the trichlorosilane cooling tower 100 together with the cooling liquid, and is extracted from the cooling tower liquid component extraction pipe 110. It is.

  The cooling liquid used for cooling and the condensed matter condensed by cooling are collected in the circulating liquid tank 400 via the cooling tower liquid component extraction pipe 110. Further, a preparation liquid made of tetrachlorosilane and / or trichlorosilane is supplied to the circulating liquid tank 400 through the preparation liquid supply pipe 401 in order to keep the concentration of tetrachlorosilane in the cooling liquid constant.

  The cooling liquid prepared in the circulating liquid tank 400 is extracted by the pump 402, cooled by the heat exchanger 403, and supplied again to the trichlorosilane cooling tower 100 through the primary cooling liquid supply pipe 104 and the secondary cooling liquid supply pipe 105. The

  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, in the above embodiment, the hydrogen chloride gas is jetted upward from the bottom of the quench pipe, but if the hydrogen chloride gas can be brought into contact with the reaction product gas after the primary cooling, the recovery rate of trichlorosilane Since the amount of the high-boiling point polymer contained in the reaction product gas after cooling can be reduced without lowering the temperature, the position and direction of injecting the hydrogen chloride gas can be changed as appropriate. Further, the reaction product gas and hydrogen chloride gas may be brought into contact with the reaction product gas extracted from the trichlorosilane cooling tower.

<Examples 1 and 2>
In both Examples 1 and 2, the apparatus shown in FIG. 1 was used. In Examples 1 and 2, the primary spray nozzle 102 and the secondary spray nozzle 103 capable of spraying the coolant with different average droplet particle sizes were used.
The reaction furnace 201 has an inner diameter of 50 mm and a length of 800 mm, and is heated by the heater 202. The reaction furnace 201 was heated so that the central portion of the reaction furnace 201 was 1300 ° C. The metal container 101 was provided with a quenching tube 106 having an inner diameter of 140 mm and a length of 1300 mm, and an inner diameter of 35 mm and a length of 420 mm and having a bottom opened.

  A raw material gas composed of tetrachlorosilane and hydrogen previously heated to 600 ° C. is continuously supplied to the reaction furnace 201 through the raw material gas supply pipe 200 at a flow rate of 27 mol / hour, and the gas reacted in the reaction furnace 201 is further supplied to the reaction furnace. The gas was supplied to the quenching pipe 106 installed inside the metal container 101 through the gas extraction pipe 203. The raw material tetrachlorosilane was 33 mol% with respect to the total of tetrachlorosilane and hydrogen.

  On the other hand, the circulating liquid tank 400 is previously filled with 13 moles of a cooling liquid composed of a mixture of trichlorosilane and tetrachlorosilane (molar ratio = 85: 15), and the heat exchanger 403 is cooled with cooling water at 20 ° C. 402 was driven, and the coolant in the circulating fluid tank 400 was sprayed continuously into the quench pipe 106 and the metal container 101 through the primary spray nozzle 102 and the secondary spray nozzle 103, respectively.

In both cases of Examples 1 and 2, the coolant supplied through the primary spray nozzle 102 has a spray amount of 0.1 l / min and a spray pressure of 0.15 MPa, and passes through the secondary spray nozzle 103. The supplied coolant was sprayed with a spray amount of 0.6 l / min and a spray pressure of 0.15 MPa.
The temperature of the cooling liquid was kept at 30 ° C. by passing through the heat exchanger 403. The coolant extracted from the bottom of the metal vessel 101 was collected in the circulating fluid tank 400 and used continuously. If necessary, the cooling liquid was continuously supplemented with tetrachlorosilane through the preparation liquid supply pipe 401 to keep the tetrachlorosilane concentration constant.

The gas component taken out from the top of the trichlorosilane cooling tower 100 is divided into a condensate containing chlorosilanes and an uncondensed gas component containing hydrogen chloride and hydrogen in the condenser 300, and the non-condensed gas component is supplied with hydrogen chloride gas. It was supplied to the hydrogen chloride gas injection nozzle 113 through the pipe 114, and was injected as hydrogen chloride gas into the trichlorosilane cooling tower 100 under the conditions of an injection amount of 20 l / min and an injection pressure of 0.1 MPa. The temperature of hydrogen chloride gas at the time of injection was 20 ° C.
On the other hand, the condensate containing chlorosilanes was temporarily stored in the storage tank 301 and then led to a distillation column (not shown), where trichlorosilane was separated and recovered.

<Comparative Example 1>
In Comparative Example 1, the same apparatus as in Example 1 was used except that hydrogen chloride gas was not injected into the trichlorosilane cooling tower 100.

<Comparative example 2>
In Comparative Example 2, the same apparatus as in Example 2 was used except that hydrogen chloride gas was not injected into the trichlorosilane cooling tower 100.

<Comparative Example 3>
Comparative Example 3 is the same as Example 1 except that an injection nozzle similar to the hydrogen chloride gas injection nozzle 113 is installed instead of the primary spray nozzle 102, and a hydrogen chloride gas supply pipe 114 is branched and connected thereto. A device was used. As a result, in Comparative Example 3, primary cooling of the reaction product gas in the quench pipe 106 was performed by mixing with hydrogen chloride gas.

  For each of Examples 1-2 and Comparative Examples 1-3, the reaction product gas temperature immediately after the primary cooling (the temperature of the reaction product gas passing through the discharge opening 112 of the quench pipe 106), the final temperature of the reaction product gas ( The temperature of the reaction product gas immediately after being extracted from the top of the trichlorosilane cooling tower 100), the high-boiling polymer content in the reaction product gas (the amount of high-boiling polymer condensed in the trichlorosilane cooling tower 100), In addition, the recovered amount of trichlorosilane condensed from the reaction product gas through the condenser 300 was examined. The results are shown in Table 1 below.

<Consideration of results>
From the comparison between Example 1 and Comparative Example 1, it is confirmed that the content of the high-boiling point polymer in the reaction product gas can be reduced to 1/90 or less by injecting hydrogen chloride gas into the reaction product gas after the primary cooling. It was done. Similarly, from the comparison between Example 2 and Comparative Example 2, the content of the high boiling point polymer in the reaction product gas is reduced to about 1/6 by injecting hydrogen chloride gas into the reaction product gas after the primary cooling. It was confirmed that it can be reduced. On the other hand, from the comparison between Example 1 and Comparative Example 3, it was confirmed that when the primary cooling of the reaction product gas was performed by contact with hydrogen chloride gas, the amount of trichlorosilane recovered was reduced by nearly 20%. It was. This is probably because a large amount of hydrogen chloride was introduced when the reaction product gas was in an equilibrium state, so that the hydrogen chloride concentration in the reaction system increased and the equilibrium was pushed back to the tetrachlorosilane side. Further, from the comparison between Example 1 and Example 2, by reducing the average droplet diameter of the cooling liquid, the recovery amount of the target trichlorosilane is improved, but the content of the high boiling point polymer is increased. Confirmed to do. This is because the cooling efficiency has been improved by reducing the average droplet diameter of the cooling liquid. As a result, the equilibrium can be frozen more instantly and the loss of trichlorosilane can be reduced, while the amount of by-product of high-boiling polymer increases. In addition, it is conceivable that the reaction product gas after the primary cooling was cooled to below the optimum decomposition temperature of the high boiling point polymer.

  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 (7)

A coolant is sprayed on a reaction product gas containing trichlorosilane obtained by reacting a raw material gas containing tetrachlorosilane and hydrogen at a temperature in the range of 700 to 1400 ° C., and cooled to a temperature range of 70 to 600 ° C. Spraying means to
Injection means for bringing hydrogen chloride gas into contact with the reaction product gas after cooling;
A trichlorosilane cooling tower.   The trichlorosilane cooling tower according to claim 1, wherein the spraying means cools the reaction product gas containing trichlorosilane to a temperature range of 500 to 600 ° C.   The trichlorosilane cooling tower according to claim 1, wherein the spraying means sprays a coolant having an average droplet particle size of 2000 μm or less.   The trichlorosilane cooling tower according to claim 1, further comprising a secondary cooling means for spraying a cooling liquid on the reaction product gas after cooling to cool to a temperature range of 30 to 60 ° C.   The trichlorosilane cooling tower according to claim 4, wherein the secondary cooling means sprays a cooling liquid having an average droplet particle size of 2000 μm or less.   The trichlorosilane cooling tower according to claim 1, wherein the hydrogen chloride gas is separated from the reaction product gas. A coolant is sprayed on a reaction product gas containing trichlorosilane obtained by reacting a raw material gas containing tetrachlorosilane and hydrogen at a temperature in the range of 700 to 1400 ° C., and cooled to a temperature range of 70 to 600 ° C. And a process of
A step of bringing hydrogen chloride gas into contact with the reaction product gas after cooling;
A method for producing trichlorosilane.

Images